drivers/md/raid5.c

0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /*
0003  * raid5.c : Multiple Devices driver for Linux
0004  *     Copyright (C) 1996, 1997 Ingo Molnar, Miguel de Icaza, Gadi Oxman
0005  *     Copyright (C) 1999, 2000 Ingo Molnar
0006  *     Copyright (C) 2002, 2003 H. Peter Anvin
0007  *
0008  * RAID-4/5/6 management functions.
0009  * Thanks to Penguin Computing for making the RAID-6 development possible
0010  * by donating a test server!
0011  */
0012
0013 /*
0014  * BITMAP UNPLUGGING:
0015  *
0016  * The sequencing for updating the bitmap reliably is a little
0017  * subtle (and I got it wrong the first time) so it deserves some
0018  * explanation.
0019  *
0020  * We group bitmap updates into batches.  Each batch has a number.
0021  * We may write out several batches at once, but that isn't very important.
0022  * conf->seq_write is the number of the last batch successfully written.
0023  * conf->seq_flush is the number of the last batch that was closed to
0024  *    new additions.
0025  * When we discover that we will need to write to any block in a stripe
0026  * (in add_stripe_bio) we update the in-memory bitmap and record in sh->bm_seq
0027  * the number of the batch it will be in. This is seq_flush+1.
0028  * When we are ready to do a write, if that batch hasn't been written yet,
0029  *   we plug the array and queue the stripe for later.
0030  * When an unplug happens, we increment bm_flush, thus closing the current
0031  *   batch.
0032  * When we notice that bm_flush > bm_write, we write out all pending updates
0033  * to the bitmap, and advance bm_write to where bm_flush was.
0034  * This may occasionally write a bit out twice, but is sure never to
0035  * miss any bits.
0036  */
0037
0038 #include <linux/blkdev.h>
0039 #include <linux/kthread.h>
0040 #include <linux/raid/pq.h>
0041 #include <linux/async_tx.h>
0042 #include <linux/module.h>
0043 #include <linux/async.h>
0044 #include <linux/seq_file.h>
0045 #include <linux/cpu.h>
0046 #include <linux/slab.h>
0047 #include <linux/ratelimit.h>
0048 #include <linux/nodemask.h>
0049
0050 #include <trace/events/block.h>
0051 #include <linux/list_sort.h>
0052
0053 #include "md.h"
0054 #include "raid5.h"
0055 #include "raid0.h"
0056 #include "md-bitmap.h"
0057 #include "raid5-log.h"
0058
0059 #define UNSUPPORTED_MDDEV_FLAGS (1L << MD_FAILFAST_SUPPORTED)
0060
0061 #define cpu_to_group(cpu) cpu_to_node(cpu)
0062 #define ANY_GROUP NUMA_NO_NODE
0063
0064 #define RAID5_MAX_REQ_STRIPES 256
0065
0066 static bool devices_handle_discard_safely = false;
0067 module_param(devices_handle_discard_safely, bool, 0644);
0068 MODULE_PARM_DESC(devices_handle_discard_safely,
0069          "Set to Y if all devices in each array reliably return zeroes on reads from discarded regions");
0070 static struct workqueue_struct *raid5_wq;
0071
0072 static inline struct hlist_head *stripe_hash(struct r5conf *conf, sector_t sect)
0073 {
0074     int hash = (sect >> RAID5_STRIPE_SHIFT(conf)) & HASH_MASK;
0075     return &conf->stripe_hashtbl[hash];
0076 }
0077
0078 static inline int stripe_hash_locks_hash(struct r5conf *conf, sector_t sect)
0079 {
0080     return (sect >> RAID5_STRIPE_SHIFT(conf)) & STRIPE_HASH_LOCKS_MASK;
0081 }
0082
0083 static inline void lock_device_hash_lock(struct r5conf *conf, int hash)
0084     __acquires(&conf->device_lock)
0085 {
0086     spin_lock_irq(conf->hash_locks + hash);
0087     spin_lock(&conf->device_lock);
0088 }
0089
0090 static inline void unlock_device_hash_lock(struct r5conf *conf, int hash)
0091     __releases(&conf->device_lock)
0092 {
0093     spin_unlock(&conf->device_lock);
0094     spin_unlock_irq(conf->hash_locks + hash);
0095 }
0096
0097 static inline void lock_all_device_hash_locks_irq(struct r5conf *conf)
0098     __acquires(&conf->device_lock)
0099 {
0100     int i;
0101     spin_lock_irq(conf->hash_locks);
0102     for (i = 1; i < NR_STRIPE_HASH_LOCKS; i++)
0103         spin_lock_nest_lock(conf->hash_locks + i, conf->hash_locks);
0104     spin_lock(&conf->device_lock);
0105 }
0106
0107 static inline void unlock_all_device_hash_locks_irq(struct r5conf *conf)
0108     __releases(&conf->device_lock)
0109 {
0110     int i;
0111     spin_unlock(&conf->device_lock);
0112     for (i = NR_STRIPE_HASH_LOCKS - 1; i; i--)
0113         spin_unlock(conf->hash_locks + i);
0114     spin_unlock_irq(conf->hash_locks);
0115 }
0116
0117 /* Find first data disk in a raid6 stripe */
0118 static inline int raid6_d0(struct stripe_head *sh)
0119 {
0120     if (sh->ddf_layout)
0121         /* ddf always start from first device */
0122         return 0;
0123     /* md starts just after Q block */
0124     if (sh->qd_idx == sh->disks - 1)
0125         return 0;
0126     else
0127         return sh->qd_idx + 1;
0128 }
0129 static inline int raid6_next_disk(int disk, int raid_disks)
0130 {
0131     disk++;
0132     return (disk < raid_disks) ? disk : 0;
0133 }
0134
0135 /* When walking through the disks in a raid5, starting at raid6_d0,
0136  * We need to map each disk to a 'slot', where the data disks are slot
0137  * 0 .. raid_disks-3, the parity disk is raid_disks-2 and the Q disk
0138  * is raid_disks-1.  This help does that mapping.
0139  */
0140 static int raid6_idx_to_slot(int idx, struct stripe_head *sh,
0141                  int *count, int syndrome_disks)
0142 {
0143     int slot = *count;
0144
0145     if (sh->ddf_layout)
0146         (*count)++;
0147     if (idx == sh->pd_idx)
0148         return syndrome_disks;
0149     if (idx == sh->qd_idx)
0150         return syndrome_disks + 1;
0151     if (!sh->ddf_layout)
0152         (*count)++;
0153     return slot;
0154 }
0155
0156 static void print_raid5_conf (struct r5conf *conf);
0157
0158 static int stripe_operations_active(struct stripe_head *sh)
0159 {
0160     return sh->check_state || sh->reconstruct_state ||
0161            test_bit(STRIPE_BIOFILL_RUN, &sh->state) ||
0162            test_bit(STRIPE_COMPUTE_RUN, &sh->state);
0163 }
0164
0165 static bool stripe_is_lowprio(struct stripe_head *sh)
0166 {
0167     return (test_bit(STRIPE_R5C_FULL_STRIPE, &sh->state) ||
0168         test_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state)) &&
0169            !test_bit(STRIPE_R5C_CACHING, &sh->state);
0170 }
0171
0172 static void raid5_wakeup_stripe_thread(struct stripe_head *sh)
0173     __must_hold(&sh->raid_conf->device_lock)
0174 {
0175     struct r5conf *conf = sh->raid_conf;
0176     struct r5worker_group *group;
0177     int thread_cnt;
0178     int i, cpu = sh->cpu;
0179
0180     if (!cpu_online(cpu)) {
0181         cpu = cpumask_any(cpu_online_mask);
0182         sh->cpu = cpu;
0183     }
0184
0185     if (list_empty(&sh->lru)) {
0186         struct r5worker_group *group;
0187         group = conf->worker_groups + cpu_to_group(cpu);
0188         if (stripe_is_lowprio(sh))
0189             list_add_tail(&sh->lru, &group->loprio_list);
0190         else
0191             list_add_tail(&sh->lru, &group->handle_list);
0192         group->stripes_cnt++;
0193         sh->group = group;
0194     }
0195
0196     if (conf->worker_cnt_per_group == 0) {
0197         md_wakeup_thread(conf->mddev->thread);
0198         return;
0199     }
0200
0201     group = conf->worker_groups + cpu_to_group(sh->cpu);
0202
0203     group->workers[0].working = true;
0204     /* at least one worker should run to avoid race */
0205     queue_work_on(sh->cpu, raid5_wq, &group->workers[0].work);
0206
0207     thread_cnt = group->stripes_cnt / MAX_STRIPE_BATCH - 1;
0208     /* wakeup more workers */
0209     for (i = 1; i < conf->worker_cnt_per_group && thread_cnt > 0; i++) {
0210         if (group->workers[i].working == false) {
0211             group->workers[i].working = true;
0212             queue_work_on(sh->cpu, raid5_wq,
0213                       &group->workers[i].work);
0214             thread_cnt--;
0215         }
0216     }
0217 }
0218
0219 static void do_release_stripe(struct r5conf *conf, struct stripe_head *sh,
0220                   struct list_head *temp_inactive_list)
0221     __must_hold(&conf->device_lock)
0222 {
0223     int i;
0224     int injournal = 0;  /* number of date pages with R5_InJournal */
0225
0226     BUG_ON(!list_empty(&sh->lru));
0227     BUG_ON(atomic_read(&conf->active_stripes)==0);
0228
0229     if (r5c_is_writeback(conf->log))
0230         for (i = sh->disks; i--; )
0231             if (test_bit(R5_InJournal, &sh->dev[i].flags))
0232                 injournal++;
0233     /*
0234      * In the following cases, the stripe cannot be released to cached
0235      * lists. Therefore, we make the stripe write out and set
0236      * STRIPE_HANDLE:
0237      *   1. when quiesce in r5c write back;
0238      *   2. when resync is requested fot the stripe.
0239      */
0240     if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state) ||
0241         (conf->quiesce && r5c_is_writeback(conf->log) &&
0242          !test_bit(STRIPE_HANDLE, &sh->state) && injournal != 0)) {
0243         if (test_bit(STRIPE_R5C_CACHING, &sh->state))
0244             r5c_make_stripe_write_out(sh);
0245         set_bit(STRIPE_HANDLE, &sh->state);
0246     }
0247
0248     if (test_bit(STRIPE_HANDLE, &sh->state)) {
0249         if (test_bit(STRIPE_DELAYED, &sh->state) &&
0250             !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
0251             list_add_tail(&sh->lru, &conf->delayed_list);
0252         else if (test_bit(STRIPE_BIT_DELAY, &sh->state) &&
0253                sh->bm_seq - conf->seq_write > 0)
0254             list_add_tail(&sh->lru, &conf->bitmap_list);
0255         else {
0256             clear_bit(STRIPE_DELAYED, &sh->state);
0257             clear_bit(STRIPE_BIT_DELAY, &sh->state);
0258             if (conf->worker_cnt_per_group == 0) {
0259                 if (stripe_is_lowprio(sh))
0260                     list_add_tail(&sh->lru,
0261                             &conf->loprio_list);
0262                 else
0263                     list_add_tail(&sh->lru,
0264                             &conf->handle_list);
0265             } else {
0266                 raid5_wakeup_stripe_thread(sh);
0267                 return;
0268             }
0269         }
0270         md_wakeup_thread(conf->mddev->thread);
0271     } else {
0272         BUG_ON(stripe_operations_active(sh));
0273         if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
0274             if (atomic_dec_return(&conf->preread_active_stripes)
0275                 < IO_THRESHOLD)
0276                 md_wakeup_thread(conf->mddev->thread);
0277         atomic_dec(&conf->active_stripes);
0278         if (!test_bit(STRIPE_EXPANDING, &sh->state)) {
0279             if (!r5c_is_writeback(conf->log))
0280                 list_add_tail(&sh->lru, temp_inactive_list);
0281             else {
0282                 WARN_ON(test_bit(R5_InJournal, &sh->dev[sh->pd_idx].flags));
0283                 if (injournal == 0)
0284                     list_add_tail(&sh->lru, temp_inactive_list);
0285                 else if (injournal == conf->raid_disks - conf->max_degraded) {
0286                     /* full stripe */
0287                     if (!test_and_set_bit(STRIPE_R5C_FULL_STRIPE, &sh->state))
0288                         atomic_inc(&conf->r5c_cached_full_stripes);
0289                     if (test_and_clear_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state))
0290                         atomic_dec(&conf->r5c_cached_partial_stripes);
0291                     list_add_tail(&sh->lru, &conf->r5c_full_stripe_list);
0292                     r5c_check_cached_full_stripe(conf);
0293                 } else
0294                     /*
0295                      * STRIPE_R5C_PARTIAL_STRIPE is set in
0296                      * r5c_try_caching_write(). No need to
0297                      * set it again.
0298                      */
0299                     list_add_tail(&sh->lru, &conf->r5c_partial_stripe_list);
0300             }
0301         }
0302     }
0303 }
0304
0305 static void __release_stripe(struct r5conf *conf, struct stripe_head *sh,
0306                  struct list_head *temp_inactive_list)
0307     __must_hold(&conf->device_lock)
0308 {
0309     if (atomic_dec_and_test(&sh->count))
0310         do_release_stripe(conf, sh, temp_inactive_list);
0311 }
0312
0313 /*
0314  * @hash could be NR_STRIPE_HASH_LOCKS, then we have a list of inactive_list
0315  *
0316  * Be careful: Only one task can add/delete stripes from temp_inactive_list at
0317  * given time. Adding stripes only takes device lock, while deleting stripes
0318  * only takes hash lock.
0319  */
0320 static void release_inactive_stripe_list(struct r5conf *conf,
0321                      struct list_head *temp_inactive_list,
0322                      int hash)
0323 {
0324     int size;
0325     bool do_wakeup = false;
0326     unsigned long flags;
0327
0328     if (hash == NR_STRIPE_HASH_LOCKS) {
0329         size = NR_STRIPE_HASH_LOCKS;
0330         hash = NR_STRIPE_HASH_LOCKS - 1;
0331     } else
0332         size = 1;
0333     while (size) {
0334         struct list_head *list = &temp_inactive_list[size - 1];
0335
0336         /*
0337          * We don't hold any lock here yet, raid5_get_active_stripe() might
0338          * remove stripes from the list
0339          */
0340         if (!list_empty_careful(list)) {
0341             spin_lock_irqsave(conf->hash_locks + hash, flags);
0342             if (list_empty(conf->inactive_list + hash) &&
0343                 !list_empty(list))
0344                 atomic_dec(&conf->empty_inactive_list_nr);
0345             list_splice_tail_init(list, conf->inactive_list + hash);
0346             do_wakeup = true;
0347             spin_unlock_irqrestore(conf->hash_locks + hash, flags);
0348         }
0349         size--;
0350         hash--;
0351     }
0352
0353     if (do_wakeup) {
0354         wake_up(&conf->wait_for_stripe);
0355         if (atomic_read(&conf->active_stripes) == 0)
0356             wake_up(&conf->wait_for_quiescent);
0357         if (conf->retry_read_aligned)
0358             md_wakeup_thread(conf->mddev->thread);
0359     }
0360 }
0361
0362 static int release_stripe_list(struct r5conf *conf,
0363                    struct list_head *temp_inactive_list)
0364     __must_hold(&conf->device_lock)
0365 {
0366     struct stripe_head *sh, *t;
0367     int count = 0;
0368     struct llist_node *head;
0369
0370     head = llist_del_all(&conf->released_stripes);
0371     head = llist_reverse_order(head);
0372     llist_for_each_entry_safe(sh, t, head, release_list) {
0373         int hash;
0374
0375         /* sh could be readded after STRIPE_ON_RELEASE_LIST is cleard */
0376         smp_mb();
0377         clear_bit(STRIPE_ON_RELEASE_LIST, &sh->state);
0378         /*
0379          * Don't worry the bit is set here, because if the bit is set
0380          * again, the count is always > 1. This is true for
0381          * STRIPE_ON_UNPLUG_LIST bit too.
0382          */
0383         hash = sh->hash_lock_index;
0384         __release_stripe(conf, sh, &temp_inactive_list[hash]);
0385         count++;
0386     }
0387
0388     return count;
0389 }
0390
0391 void raid5_release_stripe(struct stripe_head *sh)
0392 {
0393     struct r5conf *conf = sh->raid_conf;
0394     unsigned long flags;
0395     struct list_head list;
0396     int hash;
0397     bool wakeup;
0398
0399     /* Avoid release_list until the last reference.
0400      */
0401     if (atomic_add_unless(&sh->count, -1, 1))
0402         return;
0403
0404     if (unlikely(!conf->mddev->thread) ||
0405         test_and_set_bit(STRIPE_ON_RELEASE_LIST, &sh->state))
0406         goto slow_path;
0407     wakeup = llist_add(&sh->release_list, &conf->released_stripes);
0408     if (wakeup)
0409         md_wakeup_thread(conf->mddev->thread);
0410     return;
0411 slow_path:
0412     /* we are ok here if STRIPE_ON_RELEASE_LIST is set or not */
0413     if (atomic_dec_and_lock_irqsave(&sh->count, &conf->device_lock, flags)) {
0414         INIT_LIST_HEAD(&list);
0415         hash = sh->hash_lock_index;
0416         do_release_stripe(conf, sh, &list);
0417         spin_unlock_irqrestore(&conf->device_lock, flags);
0418         release_inactive_stripe_list(conf, &list, hash);
0419     }
0420 }
0421
0422 static inline void remove_hash(struct stripe_head *sh)
0423 {
0424     pr_debug("remove_hash(), stripe %llu\n",
0425         (unsigned long long)sh->sector);
0426
0427     hlist_del_init(&sh->hash);
0428 }
0429
0430 static inline void insert_hash(struct r5conf *conf, struct stripe_head *sh)
0431 {
0432     struct hlist_head *hp = stripe_hash(conf, sh->sector);
0433
0434     pr_debug("insert_hash(), stripe %llu\n",
0435         (unsigned long long)sh->sector);
0436
0437     hlist_add_head(&sh->hash, hp);
0438 }
0439
0440 /* find an idle stripe, make sure it is unhashed, and return it. */
0441 static struct stripe_head *get_free_stripe(struct r5conf *conf, int hash)
0442 {
0443     struct stripe_head *sh = NULL;
0444     struct list_head *first;
0445
0446     if (list_empty(conf->inactive_list + hash))
0447         goto out;
0448     first = (conf->inactive_list + hash)->next;
0449     sh = list_entry(first, struct stripe_head, lru);
0450     list_del_init(first);
0451     remove_hash(sh);
0452     atomic_inc(&conf->active_stripes);
0453     BUG_ON(hash != sh->hash_lock_index);
0454     if (list_empty(conf->inactive_list + hash))
0455         atomic_inc(&conf->empty_inactive_list_nr);
0456 out:
0457     return sh;
0458 }
0459
0460 #if PAGE_SIZE != DEFAULT_STRIPE_SIZE
0461 static void free_stripe_pages(struct stripe_head *sh)
0462 {
0463     int i;
0464     struct page *p;
0465
0466     /* Have not allocate page pool */
0467     if (!sh->pages)
0468         return;
0469
0470     for (i = 0; i < sh->nr_pages; i++) {
0471         p = sh->pages[i];
0472         if (p)
0473             put_page(p);
0474         sh->pages[i] = NULL;
0475     }
0476 }
0477
0478 static int alloc_stripe_pages(struct stripe_head *sh, gfp_t gfp)
0479 {
0480     int i;
0481     struct page *p;
0482
0483     for (i = 0; i < sh->nr_pages; i++) {
0484         /* The page have allocated. */
0485         if (sh->pages[i])
0486             continue;
0487
0488         p = alloc_page(gfp);
0489         if (!p) {
0490             free_stripe_pages(sh);
0491             return -ENOMEM;
0492         }
0493         sh->pages[i] = p;
0494     }
0495     return 0;
0496 }
0497
0498 static int
0499 init_stripe_shared_pages(struct stripe_head *sh, struct r5conf *conf, int disks)
0500 {
0501     int nr_pages, cnt;
0502
0503     if (sh->pages)
0504         return 0;
0505
0506     /* Each of the sh->dev[i] need one conf->stripe_size */
0507     cnt = PAGE_SIZE / conf->stripe_size;
0508     nr_pages = (disks + cnt - 1) / cnt;
0509
0510     sh->pages = kcalloc(nr_pages, sizeof(struct page *), GFP_KERNEL);
0511     if (!sh->pages)
0512         return -ENOMEM;
0513     sh->nr_pages = nr_pages;
0514     sh->stripes_per_page = cnt;
0515     return 0;
0516 }
0517 #endif
0518
0519 static void shrink_buffers(struct stripe_head *sh)
0520 {
0521     int i;
0522     int num = sh->raid_conf->pool_size;
0523
0524 #if PAGE_SIZE == DEFAULT_STRIPE_SIZE
0525     for (i = 0; i < num ; i++) {
0526         struct page *p;
0527
0528         WARN_ON(sh->dev[i].page != sh->dev[i].orig_page);
0529         p = sh->dev[i].page;
0530         if (!p)
0531             continue;
0532         sh->dev[i].page = NULL;
0533         put_page(p);
0534     }
0535 #else
0536     for (i = 0; i < num; i++)
0537         sh->dev[i].page = NULL;
0538     free_stripe_pages(sh); /* Free pages */
0539 #endif
0540 }
0541
0542 static int grow_buffers(struct stripe_head *sh, gfp_t gfp)
0543 {
0544     int i;
0545     int num = sh->raid_conf->pool_size;
0546
0547 #if PAGE_SIZE == DEFAULT_STRIPE_SIZE
0548     for (i = 0; i < num; i++) {
0549         struct page *page;
0550
0551         if (!(page = alloc_page(gfp))) {
0552             return 1;
0553         }
0554         sh->dev[i].page = page;
0555         sh->dev[i].orig_page = page;
0556         sh->dev[i].offset = 0;
0557     }
0558 #else
0559     if (alloc_stripe_pages(sh, gfp))
0560         return -ENOMEM;
0561
0562     for (i = 0; i < num; i++) {
0563         sh->dev[i].page = raid5_get_dev_page(sh, i);
0564         sh->dev[i].orig_page = sh->dev[i].page;
0565         sh->dev[i].offset = raid5_get_page_offset(sh, i);
0566     }
0567 #endif
0568     return 0;
0569 }
0570
0571 static void stripe_set_idx(sector_t stripe, struct r5conf *conf, int previous,
0572                 struct stripe_head *sh);
0573
0574 static void init_stripe(struct stripe_head *sh, sector_t sector, int previous)
0575 {
0576     struct r5conf *conf = sh->raid_conf;
0577     int i, seq;
0578
0579     BUG_ON(atomic_read(&sh->count) != 0);
0580     BUG_ON(test_bit(STRIPE_HANDLE, &sh->state));
0581     BUG_ON(stripe_operations_active(sh));
0582     BUG_ON(sh->batch_head);
0583
0584     pr_debug("init_stripe called, stripe %llu\n",
0585         (unsigned long long)sector);
0586 retry:
0587     seq = read_seqcount_begin(&conf->gen_lock);
0588     sh->generation = conf->generation - previous;
0589     sh->disks = previous ? conf->previous_raid_disks : conf->raid_disks;
0590     sh->sector = sector;
0591     stripe_set_idx(sector, conf, previous, sh);
0592     sh->state = 0;
0593
0594     for (i = sh->disks; i--; ) {
0595         struct r5dev *dev = &sh->dev[i];
0596
0597         if (dev->toread || dev->read || dev->towrite || dev->written ||
0598             test_bit(R5_LOCKED, &dev->flags)) {
0599             pr_err("sector=%llx i=%d %p %p %p %p %d\n",
0600                    (unsigned long long)sh->sector, i, dev->toread,
0601                    dev->read, dev->towrite, dev->written,
0602                    test_bit(R5_LOCKED, &dev->flags));
0603             WARN_ON(1);
0604         }
0605         dev->flags = 0;
0606         dev->sector = raid5_compute_blocknr(sh, i, previous);
0607     }
0608     if (read_seqcount_retry(&conf->gen_lock, seq))
0609         goto retry;
0610     sh->overwrite_disks = 0;
0611     insert_hash(conf, sh);
0612     sh->cpu = smp_processor_id();
0613     set_bit(STRIPE_BATCH_READY, &sh->state);
0614 }
0615
0616 static struct stripe_head *__find_stripe(struct r5conf *conf, sector_t sector,
0617                      short generation)
0618 {
0619     struct stripe_head *sh;
0620
0621     pr_debug("__find_stripe, sector %llu\n", (unsigned long long)sector);
0622     hlist_for_each_entry(sh, stripe_hash(conf, sector), hash)
0623         if (sh->sector == sector && sh->generation == generation)
0624             return sh;
0625     pr_debug("__stripe %llu not in cache\n", (unsigned long long)sector);
0626     return NULL;
0627 }
0628
0629 static struct stripe_head *find_get_stripe(struct r5conf *conf,
0630         sector_t sector, short generation, int hash)
0631 {
0632     int inc_empty_inactive_list_flag;
0633     struct stripe_head *sh;
0634
0635     sh = __find_stripe(conf, sector, generation);
0636     if (!sh)
0637         return NULL;
0638
0639     if (atomic_inc_not_zero(&sh->count))
0640         return sh;
0641
0642     /*
0643      * Slow path. The reference count is zero which means the stripe must
0644      * be on a list (sh->lru). Must remove the stripe from the list that
0645      * references it with the device_lock held.
0646      */
0647
0648     spin_lock(&conf->device_lock);
0649     if (!atomic_read(&sh->count)) {
0650         if (!test_bit(STRIPE_HANDLE, &sh->state))
0651             atomic_inc(&conf->active_stripes);
0652         BUG_ON(list_empty(&sh->lru) &&
0653                !test_bit(STRIPE_EXPANDING, &sh->state));
0654         inc_empty_inactive_list_flag = 0;
0655         if (!list_empty(conf->inactive_list + hash))
0656             inc_empty_inactive_list_flag = 1;
0657         list_del_init(&sh->lru);
0658         if (list_empty(conf->inactive_list + hash) &&
0659             inc_empty_inactive_list_flag)
0660             atomic_inc(&conf->empty_inactive_list_nr);
0661         if (sh->group) {
0662             sh->group->stripes_cnt--;
0663             sh->group = NULL;
0664         }
0665     }
0666     atomic_inc(&sh->count);
0667     spin_unlock(&conf->device_lock);
0668
0669     return sh;
0670 }
0671
0672 /*
0673  * Need to check if array has failed when deciding whether to:
0674  *  - start an array
0675  *  - remove non-faulty devices
0676  *  - add a spare
0677  *  - allow a reshape
0678  * This determination is simple when no reshape is happening.
0679  * However if there is a reshape, we need to carefully check
0680  * both the before and after sections.
0681  * This is because some failed devices may only affect one
0682  * of the two sections, and some non-in_sync devices may
0683  * be insync in the section most affected by failed devices.
0684  *
0685  * Most calls to this function hold &conf->device_lock. Calls
0686  * in raid5_run() do not require the lock as no other threads
0687  * have been started yet.
0688  */
0689 int raid5_calc_degraded(struct r5conf *conf)
0690 {
0691     int degraded, degraded2;
0692     int i;
0693
0694     rcu_read_lock();
0695     degraded = 0;
0696     for (i = 0; i < conf->previous_raid_disks; i++) {
0697         struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
0698         if (rdev && test_bit(Faulty, &rdev->flags))
0699             rdev = rcu_dereference(conf->disks[i].replacement);
0700         if (!rdev || test_bit(Faulty, &rdev->flags))
0701             degraded++;
0702         else if (test_bit(In_sync, &rdev->flags))
0703             ;
0704         else
0705             /* not in-sync or faulty.
0706              * If the reshape increases the number of devices,
0707              * this is being recovered by the reshape, so
0708              * this 'previous' section is not in_sync.
0709              * If the number of devices is being reduced however,
0710              * the device can only be part of the array if
0711              * we are reverting a reshape, so this section will
0712              * be in-sync.
0713              */
0714             if (conf->raid_disks >= conf->previous_raid_disks)
0715                 degraded++;
0716     }
0717     rcu_read_unlock();
0718     if (conf->raid_disks == conf->previous_raid_disks)
0719         return degraded;
0720     rcu_read_lock();
0721     degraded2 = 0;
0722     for (i = 0; i < conf->raid_disks; i++) {
0723         struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
0724         if (rdev && test_bit(Faulty, &rdev->flags))
0725             rdev = rcu_dereference(conf->disks[i].replacement);
0726         if (!rdev || test_bit(Faulty, &rdev->flags))
0727             degraded2++;
0728         else if (test_bit(In_sync, &rdev->flags))
0729             ;
0730         else
0731             /* not in-sync or faulty.
0732              * If reshape increases the number of devices, this
0733              * section has already been recovered, else it
0734              * almost certainly hasn't.
0735              */
0736             if (conf->raid_disks <= conf->previous_raid_disks)
0737                 degraded2++;
0738     }
0739     rcu_read_unlock();
0740     if (degraded2 > degraded)
0741         return degraded2;
0742     return degraded;
0743 }
0744
0745 static bool has_failed(struct r5conf *conf)
0746 {
0747     int degraded = conf->mddev->degraded;
0748
0749     if (test_bit(MD_BROKEN, &conf->mddev->flags))
0750         return true;
0751
0752     if (conf->mddev->reshape_position != MaxSector)
0753         degraded = raid5_calc_degraded(conf);
0754
0755     return degraded > conf->max_degraded;
0756 }
0757
0758 enum stripe_result {
0759     STRIPE_SUCCESS = 0,
0760     STRIPE_RETRY,
0761     STRIPE_SCHEDULE_AND_RETRY,
0762     STRIPE_FAIL,
0763 };
0764
0765 struct stripe_request_ctx {
0766     /* a reference to the last stripe_head for batching */
0767     struct stripe_head *batch_last;
0768
0769     /* first sector in the request */
0770     sector_t first_sector;
0771
0772     /* last sector in the request */
0773     sector_t last_sector;
0774
0775     /*
0776      * bitmap to track stripe sectors that have been added to stripes
0777      * add one to account for unaligned requests
0778      */
0779     DECLARE_BITMAP(sectors_to_do, RAID5_MAX_REQ_STRIPES + 1);
0780
0781     /* the request had REQ_PREFLUSH, cleared after the first stripe_head */
0782     bool do_flush;
0783 };
0784
0785 /*
0786  * Block until another thread clears R5_INACTIVE_BLOCKED or
0787  * there are fewer than 3/4 the maximum number of active stripes
0788  * and there is an inactive stripe available.
0789  */
0790 static bool is_inactive_blocked(struct r5conf *conf, int hash)
0791 {
0792     int active = atomic_read(&conf->active_stripes);
0793
0794     if (list_empty(conf->inactive_list + hash))
0795         return false;
0796
0797     if (!test_bit(R5_INACTIVE_BLOCKED, &conf->cache_state))
0798         return true;
0799
0800     return active < (conf->max_nr_stripes * 3 / 4);
0801 }
0802
0803 static struct stripe_head *__raid5_get_active_stripe(struct r5conf *conf,
0804         struct stripe_request_ctx *ctx, sector_t sector,
0805         bool previous, bool noblock, bool noquiesce)
0806 {
0807     struct stripe_head *sh;
0808     int hash = stripe_hash_locks_hash(conf, sector);
0809
0810     pr_debug("get_stripe, sector %llu\n", (unsigned long long)sector);
0811
0812     spin_lock_irq(conf->hash_locks + hash);
0813
0814 retry:
0815     if (!noquiesce && conf->quiesce) {
0816         /*
0817          * Must release the reference to batch_last before waiting,
0818          * on quiesce, otherwise the batch_last will hold a reference
0819          * to a stripe and raid5_quiesce() will deadlock waiting for
0820          * active_stripes to go to zero.
0821          */
0822         if (ctx && ctx->batch_last) {
0823             raid5_release_stripe(ctx->batch_last);
0824             ctx->batch_last = NULL;
0825         }
0826
0827         wait_event_lock_irq(conf->wait_for_quiescent, !conf->quiesce,
0828                     *(conf->hash_locks + hash));
0829     }
0830
0831     sh = find_get_stripe(conf, sector, conf->generation - previous, hash);
0832     if (sh)
0833         goto out;
0834
0835     if (test_bit(R5_INACTIVE_BLOCKED, &conf->cache_state))
0836         goto wait_for_stripe;
0837
0838     sh = get_free_stripe(conf, hash);
0839     if (sh) {
0840         r5c_check_stripe_cache_usage(conf);
0841         init_stripe(sh, sector, previous);
0842         atomic_inc(&sh->count);
0843         goto out;
0844     }
0845
0846     if (!test_bit(R5_DID_ALLOC, &conf->cache_state))
0847         set_bit(R5_ALLOC_MORE, &conf->cache_state);
0848
0849 wait_for_stripe:
0850     if (noblock)
0851         goto out;
0852
0853     set_bit(R5_INACTIVE_BLOCKED, &conf->cache_state);
0854     r5l_wake_reclaim(conf->log, 0);
0855     wait_event_lock_irq(conf->wait_for_stripe,
0856                 is_inactive_blocked(conf, hash),
0857                 *(conf->hash_locks + hash));
0858     clear_bit(R5_INACTIVE_BLOCKED, &conf->cache_state);
0859     goto retry;
0860
0861 out:
0862     spin_unlock_irq(conf->hash_locks + hash);
0863     return sh;
0864 }
0865
0866 struct stripe_head *raid5_get_active_stripe(struct r5conf *conf,
0867         sector_t sector, bool previous, bool noblock, bool noquiesce)
0868 {
0869     return __raid5_get_active_stripe(conf, NULL, sector, previous, noblock,
0870                      noquiesce);
0871 }
0872
0873 static bool is_full_stripe_write(struct stripe_head *sh)
0874 {
0875     BUG_ON(sh->overwrite_disks > (sh->disks - sh->raid_conf->max_degraded));
0876     return sh->overwrite_disks == (sh->disks - sh->raid_conf->max_degraded);
0877 }
0878
0879 static void lock_two_stripes(struct stripe_head *sh1, struct stripe_head *sh2)
0880         __acquires(&sh1->stripe_lock)
0881         __acquires(&sh2->stripe_lock)
0882 {
0883     if (sh1 > sh2) {
0884         spin_lock_irq(&sh2->stripe_lock);
0885         spin_lock_nested(&sh1->stripe_lock, 1);
0886     } else {
0887         spin_lock_irq(&sh1->stripe_lock);
0888         spin_lock_nested(&sh2->stripe_lock, 1);
0889     }
0890 }
0891
0892 static void unlock_two_stripes(struct stripe_head *sh1, struct stripe_head *sh2)
0893         __releases(&sh1->stripe_lock)
0894         __releases(&sh2->stripe_lock)
0895 {
0896     spin_unlock(&sh1->stripe_lock);
0897     spin_unlock_irq(&sh2->stripe_lock);
0898 }
0899
0900 /* Only freshly new full stripe normal write stripe can be added to a batch list */
0901 static bool stripe_can_batch(struct stripe_head *sh)
0902 {
0903     struct r5conf *conf = sh->raid_conf;
0904
0905     if (raid5_has_log(conf) || raid5_has_ppl(conf))
0906         return false;
0907     return test_bit(STRIPE_BATCH_READY, &sh->state) &&
0908         !test_bit(STRIPE_BITMAP_PENDING, &sh->state) &&
0909         is_full_stripe_write(sh);
0910 }
0911
0912 /* we only do back search */
0913 static void stripe_add_to_batch_list(struct r5conf *conf,
0914         struct stripe_head *sh, struct stripe_head *last_sh)
0915 {
0916     struct stripe_head *head;
0917     sector_t head_sector, tmp_sec;
0918     int hash;
0919     int dd_idx;
0920
0921     /* Don't cross chunks, so stripe pd_idx/qd_idx is the same */
0922     tmp_sec = sh->sector;
0923     if (!sector_div(tmp_sec, conf->chunk_sectors))
0924         return;
0925     head_sector = sh->sector - RAID5_STRIPE_SECTORS(conf);
0926
0927     if (last_sh && head_sector == last_sh->sector) {
0928         head = last_sh;
0929         atomic_inc(&head->count);
0930     } else {
0931         hash = stripe_hash_locks_hash(conf, head_sector);
0932         spin_lock_irq(conf->hash_locks + hash);
0933         head = find_get_stripe(conf, head_sector, conf->generation,
0934                        hash);
0935         spin_unlock_irq(conf->hash_locks + hash);
0936         if (!head)
0937             return;
0938         if (!stripe_can_batch(head))
0939             goto out;
0940     }
0941
0942     lock_two_stripes(head, sh);
0943     /* clear_batch_ready clear the flag */
0944     if (!stripe_can_batch(head) || !stripe_can_batch(sh))
0945         goto unlock_out;
0946
0947     if (sh->batch_head)
0948         goto unlock_out;
0949
0950     dd_idx = 0;
0951     while (dd_idx == sh->pd_idx || dd_idx == sh->qd_idx)
0952         dd_idx++;
0953     if (head->dev[dd_idx].towrite->bi_opf != sh->dev[dd_idx].towrite->bi_opf ||
0954         bio_op(head->dev[dd_idx].towrite) != bio_op(sh->dev[dd_idx].towrite))
0955         goto unlock_out;
0956
0957     if (head->batch_head) {
0958         spin_lock(&head->batch_head->batch_lock);
0959         /* This batch list is already running */
0960         if (!stripe_can_batch(head)) {
0961             spin_unlock(&head->batch_head->batch_lock);
0962             goto unlock_out;
0963         }
0964         /*
0965          * We must assign batch_head of this stripe within the
0966          * batch_lock, otherwise clear_batch_ready of batch head
0967          * stripe could clear BATCH_READY bit of this stripe and
0968          * this stripe->batch_head doesn't get assigned, which
0969          * could confuse clear_batch_ready for this stripe
0970          */
0971         sh->batch_head = head->batch_head;
0972
0973         /*
0974          * at this point, head's BATCH_READY could be cleared, but we
0975          * can still add the stripe to batch list
0976          */
0977         list_add(&sh->batch_list, &head->batch_list);
0978         spin_unlock(&head->batch_head->batch_lock);
0979     } else {
0980         head->batch_head = head;
0981         sh->batch_head = head->batch_head;
0982         spin_lock(&head->batch_lock);
0983         list_add_tail(&sh->batch_list, &head->batch_list);
0984         spin_unlock(&head->batch_lock);
0985     }
0986
0987     if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
0988         if (atomic_dec_return(&conf->preread_active_stripes)
0989             < IO_THRESHOLD)
0990             md_wakeup_thread(conf->mddev->thread);
0991
0992     if (test_and_clear_bit(STRIPE_BIT_DELAY, &sh->state)) {
0993         int seq = sh->bm_seq;
0994         if (test_bit(STRIPE_BIT_DELAY, &sh->batch_head->state) &&
0995             sh->batch_head->bm_seq > seq)
0996             seq = sh->batch_head->bm_seq;
0997         set_bit(STRIPE_BIT_DELAY, &sh->batch_head->state);
0998         sh->batch_head->bm_seq = seq;
0999     }
1000
1001     atomic_inc(&sh->count);
1002 unlock_out:
1003     unlock_two_stripes(head, sh);
1004 out:
1005     raid5_release_stripe(head);
1006 }
1007
1008 /* Determine if 'data_offset' or 'new_data_offset' should be used
1009  * in this stripe_head.
1010  */
1011 static int use_new_offset(struct r5conf *conf, struct stripe_head *sh)
1012 {
1013     sector_t progress = conf->reshape_progress;
1014     /* Need a memory barrier to make sure we see the value
1015      * of conf->generation, or ->data_offset that was set before
1016      * reshape_progress was updated.
1017      */
1018     smp_rmb();
1019     if (progress == MaxSector)
1020         return 0;
1021     if (sh->generation == conf->generation - 1)
1022         return 0;
1023     /* We are in a reshape, and this is a new-generation stripe,
1024      * so use new_data_offset.
1025      */
1026     return 1;
1027 }
1028
1029 static void dispatch_bio_list(struct bio_list *tmp)
1030 {
1031     struct bio *bio;
1032
1033     while ((bio = bio_list_pop(tmp)))
1034         submit_bio_noacct(bio);
1035 }
1036
1037 static int cmp_stripe(void *priv, const struct list_head *a,
1038               const struct list_head *b)
1039 {
1040     const struct r5pending_data *da = list_entry(a,
1041                 struct r5pending_data, sibling);
1042     const struct r5pending_data *db = list_entry(b,
1043                 struct r5pending_data, sibling);
1044     if (da->sector > db->sector)
1045         return 1;
1046     if (da->sector < db->sector)
1047         return -1;
1048     return 0;
1049 }
1050
1051 static void dispatch_defer_bios(struct r5conf *conf, int target,
1052                 struct bio_list *list)
1053 {
1054     struct r5pending_data *data;
1055     struct list_head *first, *next = NULL;
1056     int cnt = 0;
1057
1058     if (conf->pending_data_cnt == 0)
1059         return;
1060
1061     list_sort(NULL, &conf->pending_list, cmp_stripe);
1062
1063     first = conf->pending_list.next;
1064
1065     /* temporarily move the head */
1066     if (conf->next_pending_data)
1067         list_move_tail(&conf->pending_list,
1068                 &conf->next_pending_data->sibling);
1069
1070     while (!list_empty(&conf->pending_list)) {
1071         data = list_first_entry(&conf->pending_list,
1072             struct r5pending_data, sibling);
1073         if (&data->sibling == first)
1074             first = data->sibling.next;
1075         next = data->sibling.next;
1076
1077         bio_list_merge(list, &data->bios);
1078         list_move(&data->sibling, &conf->free_list);
1079         cnt++;
1080         if (cnt >= target)
1081             break;
1082     }
1083     conf->pending_data_cnt -= cnt;
1084     BUG_ON(conf->pending_data_cnt < 0 || cnt < target);
1085
1086     if (next != &conf->pending_list)
1087         conf->next_pending_data = list_entry(next,
1088                 struct r5pending_data, sibling);
1089     else
1090         conf->next_pending_data = NULL;
1091     /* list isn't empty */
1092     if (first != &conf->pending_list)
1093         list_move_tail(&conf->pending_list, first);
1094 }
1095
1096 static void flush_deferred_bios(struct r5conf *conf)
1097 {
1098     struct bio_list tmp = BIO_EMPTY_LIST;
1099
1100     if (conf->pending_data_cnt == 0)
1101         return;
1102
1103     spin_lock(&conf->pending_bios_lock);
1104     dispatch_defer_bios(conf, conf->pending_data_cnt, &tmp);
1105     BUG_ON(conf->pending_data_cnt != 0);
1106     spin_unlock(&conf->pending_bios_lock);
1107
1108     dispatch_bio_list(&tmp);
1109 }
1110
1111 static void defer_issue_bios(struct r5conf *conf, sector_t sector,
1112                 struct bio_list *bios)
1113 {
1114     struct bio_list tmp = BIO_EMPTY_LIST;
1115     struct r5pending_data *ent;
1116
1117     spin_lock(&conf->pending_bios_lock);
1118     ent = list_first_entry(&conf->free_list, struct r5pending_data,
1119                             sibling);
1120     list_move_tail(&ent->sibling, &conf->pending_list);
1121     ent->sector = sector;
1122     bio_list_init(&ent->bios);
1123     bio_list_merge(&ent->bios, bios);
1124     conf->pending_data_cnt++;
1125     if (conf->pending_data_cnt >= PENDING_IO_MAX)
1126         dispatch_defer_bios(conf, PENDING_IO_ONE_FLUSH, &tmp);
1127
1128     spin_unlock(&conf->pending_bios_lock);
1129
1130     dispatch_bio_list(&tmp);
1131 }
1132
1133 static void
1134 raid5_end_read_request(struct bio *bi);
1135 static void
1136 raid5_end_write_request(struct bio *bi);
1137
1138 static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s)
1139 {
1140     struct r5conf *conf = sh->raid_conf;
1141     int i, disks = sh->disks;
1142     struct stripe_head *head_sh = sh;
1143     struct bio_list pending_bios = BIO_EMPTY_LIST;
1144     struct r5dev *dev;
1145     bool should_defer;
1146
1147     might_sleep();
1148
1149     if (log_stripe(sh, s) == 0)
1150         return;
1151
1152     should_defer = conf->batch_bio_dispatch && conf->group_cnt;
1153
1154     for (i = disks; i--; ) {
1155         enum req_op op;
1156         blk_opf_t op_flags = 0;
1157         int replace_only = 0;
1158         struct bio *bi, *rbi;
1159         struct md_rdev *rdev, *rrdev = NULL;
1160
1161         sh = head_sh;
1162         if (test_and_clear_bit(R5_Wantwrite, &sh->dev[i].flags)) {
1163             op = REQ_OP_WRITE;
1164             if (test_and_clear_bit(R5_WantFUA, &sh->dev[i].flags))
1165                 op_flags = REQ_FUA;
1166             if (test_bit(R5_Discard, &sh->dev[i].flags))
1167                 op = REQ_OP_DISCARD;
1168         } else if (test_and_clear_bit(R5_Wantread, &sh->dev[i].flags))
1169             op = REQ_OP_READ;
1170         else if (test_and_clear_bit(R5_WantReplace,
1171                         &sh->dev[i].flags)) {
1172             op = REQ_OP_WRITE;
1173             replace_only = 1;
1174         } else
1175             continue;
1176         if (test_and_clear_bit(R5_SyncIO, &sh->dev[i].flags))
1177             op_flags |= REQ_SYNC;
1178
1179 again:
1180         dev = &sh->dev[i];
1181         bi = &dev->req;
1182         rbi = &dev->rreq; /* For writing to replacement */
1183
1184         rcu_read_lock();
1185         rrdev = rcu_dereference(conf->disks[i].replacement);
1186         smp_mb(); /* Ensure that if rrdev is NULL, rdev won't be */
1187         rdev = rcu_dereference(conf->disks[i].rdev);
1188         if (!rdev) {
1189             rdev = rrdev;
1190             rrdev = NULL;
1191         }
1192         if (op_is_write(op)) {
1193             if (replace_only)
1194                 rdev = NULL;
1195             if (rdev == rrdev)
1196                 /* We raced and saw duplicates */
1197                 rrdev = NULL;
1198         } else {
1199             if (test_bit(R5_ReadRepl, &head_sh->dev[i].flags) && rrdev)
1200                 rdev = rrdev;
1201             rrdev = NULL;
1202         }
1203
1204         if (rdev && test_bit(Faulty, &rdev->flags))
1205             rdev = NULL;
1206         if (rdev)
1207             atomic_inc(&rdev->nr_pending);
1208         if (rrdev && test_bit(Faulty, &rrdev->flags))
1209             rrdev = NULL;
1210         if (rrdev)
1211             atomic_inc(&rrdev->nr_pending);
1212         rcu_read_unlock();
1213
1214         /* We have already checked bad blocks for reads.  Now
1215          * need to check for writes.  We never accept write errors
1216          * on the replacement, so we don't to check rrdev.
1217          */
1218         while (op_is_write(op) && rdev &&
1219                test_bit(WriteErrorSeen, &rdev->flags)) {
1220             sector_t first_bad;
1221             int bad_sectors;
1222             int bad = is_badblock(rdev, sh->sector, RAID5_STRIPE_SECTORS(conf),
1223                           &first_bad, &bad_sectors);
1224             if (!bad)
1225                 break;
1226
1227             if (bad < 0) {
1228                 set_bit(BlockedBadBlocks, &rdev->flags);
1229                 if (!conf->mddev->external &&
1230                     conf->mddev->sb_flags) {
1231                     /* It is very unlikely, but we might
1232                      * still need to write out the
1233                      * bad block log - better give it
1234                      * a chance*/
1235                     md_check_recovery(conf->mddev);
1236                 }
1237                 /*
1238                  * Because md_wait_for_blocked_rdev
1239                  * will dec nr_pending, we must
1240                  * increment it first.
1241                  */
1242                 atomic_inc(&rdev->nr_pending);
1243                 md_wait_for_blocked_rdev(rdev, conf->mddev);
1244             } else {
1245                 /* Acknowledged bad block - skip the write */
1246                 rdev_dec_pending(rdev, conf->mddev);
1247                 rdev = NULL;
1248             }
1249         }
1250
1251         if (rdev) {
1252             if (s->syncing || s->expanding || s->expanded
1253                 || s->replacing)
1254                 md_sync_acct(rdev->bdev, RAID5_STRIPE_SECTORS(conf));
1255
1256             set_bit(STRIPE_IO_STARTED, &sh->state);
1257
1258             bio_init(bi, rdev->bdev, &dev->vec, 1, op | op_flags);
1259             bi->bi_end_io = op_is_write(op)
1260                 ? raid5_end_write_request
1261                 : raid5_end_read_request;
1262             bi->bi_private = sh;
1263
1264             pr_debug("%s: for %llu schedule op %d on disc %d\n",
1265                 __func__, (unsigned long long)sh->sector,
1266                 bi->bi_opf, i);
1267             atomic_inc(&sh->count);
1268             if (sh != head_sh)
1269                 atomic_inc(&head_sh->count);
1270             if (use_new_offset(conf, sh))
1271                 bi->bi_iter.bi_sector = (sh->sector
1272                          + rdev->new_data_offset);
1273             else
1274                 bi->bi_iter.bi_sector = (sh->sector
1275                          + rdev->data_offset);
1276             if (test_bit(R5_ReadNoMerge, &head_sh->dev[i].flags))
1277                 bi->bi_opf |= REQ_NOMERGE;
1278
1279             if (test_bit(R5_SkipCopy, &sh->dev[i].flags))
1280                 WARN_ON(test_bit(R5_UPTODATE, &sh->dev[i].flags));
1281
1282             if (!op_is_write(op) &&
1283                 test_bit(R5_InJournal, &sh->dev[i].flags))
1284                 /*
1285                  * issuing read for a page in journal, this
1286                  * must be preparing for prexor in rmw; read
1287                  * the data into orig_page
1288                  */
1289                 sh->dev[i].vec.bv_page = sh->dev[i].orig_page;
1290             else
1291                 sh->dev[i].vec.bv_page = sh->dev[i].page;
1292             bi->bi_vcnt = 1;
1293             bi->bi_io_vec[0].bv_len = RAID5_STRIPE_SIZE(conf);
1294             bi->bi_io_vec[0].bv_offset = sh->dev[i].offset;
1295             bi->bi_iter.bi_size = RAID5_STRIPE_SIZE(conf);
1296             /*
1297              * If this is discard request, set bi_vcnt 0. We don't
1298              * want to confuse SCSI because SCSI will replace payload
1299              */
1300             if (op == REQ_OP_DISCARD)
1301                 bi->bi_vcnt = 0;
1302             if (rrdev)
1303                 set_bit(R5_DOUBLE_LOCKED, &sh->dev[i].flags);
1304
1305             if (conf->mddev->gendisk)
1306                 trace_block_bio_remap(bi,
1307                         disk_devt(conf->mddev->gendisk),
1308                         sh->dev[i].sector);
1309             if (should_defer && op_is_write(op))
1310                 bio_list_add(&pending_bios, bi);
1311             else
1312                 submit_bio_noacct(bi);
1313         }
1314         if (rrdev) {
1315             if (s->syncing || s->expanding || s->expanded
1316                 || s->replacing)
1317                 md_sync_acct(rrdev->bdev, RAID5_STRIPE_SECTORS(conf));
1318
1319             set_bit(STRIPE_IO_STARTED, &sh->state);
1320
1321             bio_init(rbi, rrdev->bdev, &dev->rvec, 1, op | op_flags);
1322             BUG_ON(!op_is_write(op));
1323             rbi->bi_end_io = raid5_end_write_request;
1324             rbi->bi_private = sh;
1325
1326             pr_debug("%s: for %llu schedule op %d on "
1327                  "replacement disc %d\n",
1328                 __func__, (unsigned long long)sh->sector,
1329                 rbi->bi_opf, i);
1330             atomic_inc(&sh->count);
1331             if (sh != head_sh)
1332                 atomic_inc(&head_sh->count);
1333             if (use_new_offset(conf, sh))
1334                 rbi->bi_iter.bi_sector = (sh->sector
1335                           + rrdev->new_data_offset);
1336             else
1337                 rbi->bi_iter.bi_sector = (sh->sector
1338                           + rrdev->data_offset);
1339             if (test_bit(R5_SkipCopy, &sh->dev[i].flags))
1340                 WARN_ON(test_bit(R5_UPTODATE, &sh->dev[i].flags));
1341             sh->dev[i].rvec.bv_page = sh->dev[i].page;
1342             rbi->bi_vcnt = 1;
1343             rbi->bi_io_vec[0].bv_len = RAID5_STRIPE_SIZE(conf);
1344             rbi->bi_io_vec[0].bv_offset = sh->dev[i].offset;
1345             rbi->bi_iter.bi_size = RAID5_STRIPE_SIZE(conf);
1346             /*
1347              * If this is discard request, set bi_vcnt 0. We don't
1348              * want to confuse SCSI because SCSI will replace payload
1349              */
1350             if (op == REQ_OP_DISCARD)
1351                 rbi->bi_vcnt = 0;
1352             if (conf->mddev->gendisk)
1353                 trace_block_bio_remap(rbi,
1354                         disk_devt(conf->mddev->gendisk),
1355                         sh->dev[i].sector);
1356             if (should_defer && op_is_write(op))
1357                 bio_list_add(&pending_bios, rbi);
1358             else
1359                 submit_bio_noacct(rbi);
1360         }
1361         if (!rdev && !rrdev) {
1362             if (op_is_write(op))
1363                 set_bit(STRIPE_DEGRADED, &sh->state);
1364             pr_debug("skip op %d on disc %d for sector %llu\n",
1365                 bi->bi_opf, i, (unsigned long long)sh->sector);
1366             clear_bit(R5_LOCKED, &sh->dev[i].flags);
1367             set_bit(STRIPE_HANDLE, &sh->state);
1368         }
1369
1370         if (!head_sh->batch_head)
1371             continue;
1372         sh = list_first_entry(&sh->batch_list, struct stripe_head,
1373                       batch_list);
1374         if (sh != head_sh)
1375             goto again;
1376     }
1377
1378     if (should_defer && !bio_list_empty(&pending_bios))
1379         defer_issue_bios(conf, head_sh->sector, &pending_bios);
1380 }
1381
1382 static struct dma_async_tx_descriptor *
1383 async_copy_data(int frombio, struct bio *bio, struct page **page,
1384     unsigned int poff, sector_t sector, struct dma_async_tx_descriptor *tx,
1385     struct stripe_head *sh, int no_skipcopy)
1386 {
1387     struct bio_vec bvl;
1388     struct bvec_iter iter;
1389     struct page *bio_page;
1390     int page_offset;
1391     struct async_submit_ctl submit;
1392     enum async_tx_flags flags = 0;
1393     struct r5conf *conf = sh->raid_conf;
1394
1395     if (bio->bi_iter.bi_sector >= sector)
1396         page_offset = (signed)(bio->bi_iter.bi_sector - sector) * 512;
1397     else
1398         page_offset = (signed)(sector - bio->bi_iter.bi_sector) * -512;
1399
1400     if (frombio)
1401         flags |= ASYNC_TX_FENCE;
1402     init_async_submit(&submit, flags, tx, NULL, NULL, NULL);
1403
1404     bio_for_each_segment(bvl, bio, iter) {
1405         int len = bvl.bv_len;
1406         int clen;
1407         int b_offset = 0;
1408
1409         if (page_offset < 0) {
1410             b_offset = -page_offset;
1411             page_offset += b_offset;
1412             len -= b_offset;
1413         }
1414
1415         if (len > 0 && page_offset + len > RAID5_STRIPE_SIZE(conf))
1416             clen = RAID5_STRIPE_SIZE(conf) - page_offset;
1417         else
1418             clen = len;
1419
1420         if (clen > 0) {
1421             b_offset += bvl.bv_offset;
1422             bio_page = bvl.bv_page;
1423             if (frombio) {
1424                 if (conf->skip_copy &&
1425                     b_offset == 0 && page_offset == 0 &&
1426                     clen == RAID5_STRIPE_SIZE(conf) &&
1427                     !no_skipcopy)
1428                     *page = bio_page;
1429                 else
1430                     tx = async_memcpy(*page, bio_page, page_offset + poff,
1431                           b_offset, clen, &submit);
1432             } else
1433                 tx = async_memcpy(bio_page, *page, b_offset,
1434                           page_offset + poff, clen, &submit);
1435         }
1436         /* chain the operations */
1437         submit.depend_tx = tx;
1438
1439         if (clen < len) /* hit end of page */
1440             break;
1441         page_offset +=  len;
1442     }
1443
1444     return tx;
1445 }
1446
1447 static void ops_complete_biofill(void *stripe_head_ref)
1448 {
1449     struct stripe_head *sh = stripe_head_ref;
1450     int i;
1451     struct r5conf *conf = sh->raid_conf;
1452
1453     pr_debug("%s: stripe %llu\n", __func__,
1454         (unsigned long long)sh->sector);
1455
1456     /* clear completed biofills */
1457     for (i = sh->disks; i--; ) {
1458         struct r5dev *dev = &sh->dev[i];
1459
1460         /* acknowledge completion of a biofill operation */
1461         /* and check if we need to reply to a read request,
1462          * new R5_Wantfill requests are held off until
1463          * !STRIPE_BIOFILL_RUN
1464          */
1465         if (test_and_clear_bit(R5_Wantfill, &dev->flags)) {
1466             struct bio *rbi, *rbi2;
1467
1468             BUG_ON(!dev->read);
1469             rbi = dev->read;
1470             dev->read = NULL;
1471             while (rbi && rbi->bi_iter.bi_sector <
1472                 dev->sector + RAID5_STRIPE_SECTORS(conf)) {
1473                 rbi2 = r5_next_bio(conf, rbi, dev->sector);
1474                 bio_endio(rbi);
1475                 rbi = rbi2;
1476             }
1477         }
1478     }
1479     clear_bit(STRIPE_BIOFILL_RUN, &sh->state);
1480
1481     set_bit(STRIPE_HANDLE, &sh->state);
1482     raid5_release_stripe(sh);
1483 }
1484
1485 static void ops_run_biofill(struct stripe_head *sh)
1486 {
1487     struct dma_async_tx_descriptor *tx = NULL;
1488     struct async_submit_ctl submit;
1489     int i;
1490     struct r5conf *conf = sh->raid_conf;
1491
1492     BUG_ON(sh->batch_head);
1493     pr_debug("%s: stripe %llu\n", __func__,
1494         (unsigned long long)sh->sector);
1495
1496     for (i = sh->disks; i--; ) {
1497         struct r5dev *dev = &sh->dev[i];
1498         if (test_bit(R5_Wantfill, &dev->flags)) {
1499             struct bio *rbi;
1500             spin_lock_irq(&sh->stripe_lock);
1501             dev->read = rbi = dev->toread;
1502             dev->toread = NULL;
1503             spin_unlock_irq(&sh->stripe_lock);
1504             while (rbi && rbi->bi_iter.bi_sector <
1505                 dev->sector + RAID5_STRIPE_SECTORS(conf)) {
1506                 tx = async_copy_data(0, rbi, &dev->page,
1507                              dev->offset,
1508                              dev->sector, tx, sh, 0);
1509                 rbi = r5_next_bio(conf, rbi, dev->sector);
1510             }
1511         }
1512     }
1513
1514     atomic_inc(&sh->count);
1515     init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_biofill, sh, NULL);
1516     async_trigger_callback(&submit);
1517 }
1518
1519 static void mark_target_uptodate(struct stripe_head *sh, int target)
1520 {
1521     struct r5dev *tgt;
1522
1523     if (target < 0)
1524         return;
1525
1526     tgt = &sh->dev[target];
1527     set_bit(R5_UPTODATE, &tgt->flags);
1528     BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1529     clear_bit(R5_Wantcompute, &tgt->flags);
1530 }
1531
1532 static void ops_complete_compute(void *stripe_head_ref)
1533 {
1534     struct stripe_head *sh = stripe_head_ref;
1535
1536     pr_debug("%s: stripe %llu\n", __func__,
1537         (unsigned long long)sh->sector);
1538
1539     /* mark the computed target(s) as uptodate */
1540     mark_target_uptodate(sh, sh->ops.target);
1541     mark_target_uptodate(sh, sh->ops.target2);
1542
1543     clear_bit(STRIPE_COMPUTE_RUN, &sh->state);
1544     if (sh->check_state == check_state_compute_run)
1545         sh->check_state = check_state_compute_result;
1546     set_bit(STRIPE_HANDLE, &sh->state);
1547     raid5_release_stripe(sh);
1548 }
1549
1550 /* return a pointer to the address conversion region of the scribble buffer */
1551 static struct page **to_addr_page(struct raid5_percpu *percpu, int i)
1552 {
1553     return percpu->scribble + i * percpu->scribble_obj_size;
1554 }
1555
1556 /* return a pointer to the address conversion region of the scribble buffer */
1557 static addr_conv_t *to_addr_conv(struct stripe_head *sh,
1558                  struct raid5_percpu *percpu, int i)
1559 {
1560     return (void *) (to_addr_page(percpu, i) + sh->disks + 2);
1561 }
1562
1563 /*
1564  * Return a pointer to record offset address.
1565  */
1566 static unsigned int *
1567 to_addr_offs(struct stripe_head *sh, struct raid5_percpu *percpu)
1568 {
1569     return (unsigned int *) (to_addr_conv(sh, percpu, 0) + sh->disks + 2);
1570 }
1571
1572 static struct dma_async_tx_descriptor *
1573 ops_run_compute5(struct stripe_head *sh, struct raid5_percpu *percpu)
1574 {
1575     int disks = sh->disks;
1576     struct page **xor_srcs = to_addr_page(percpu, 0);
1577     unsigned int *off_srcs = to_addr_offs(sh, percpu);
1578     int target = sh->ops.target;
1579     struct r5dev *tgt = &sh->dev[target];
1580     struct page *xor_dest = tgt->page;
1581     unsigned int off_dest = tgt->offset;
1582     int count = 0;
1583     struct dma_async_tx_descriptor *tx;
1584     struct async_submit_ctl submit;
1585     int i;
1586
1587     BUG_ON(sh->batch_head);
1588
1589     pr_debug("%s: stripe %llu block: %d\n",
1590         __func__, (unsigned long long)sh->sector, target);
1591     BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1592
1593     for (i = disks; i--; ) {
1594         if (i != target) {
1595             off_srcs[count] = sh->dev[i].offset;
1596             xor_srcs[count++] = sh->dev[i].page;
1597         }
1598     }
1599
1600     atomic_inc(&sh->count);
1601
1602     init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST, NULL,
1603               ops_complete_compute, sh, to_addr_conv(sh, percpu, 0));
1604     if (unlikely(count == 1))
1605         tx = async_memcpy(xor_dest, xor_srcs[0], off_dest, off_srcs[0],
1606                 RAID5_STRIPE_SIZE(sh->raid_conf), &submit);
1607     else
1608         tx = async_xor_offs(xor_dest, off_dest, xor_srcs, off_srcs, count,
1609                 RAID5_STRIPE_SIZE(sh->raid_conf), &submit);
1610
1611     return tx;
1612 }
1613
1614 /* set_syndrome_sources - populate source buffers for gen_syndrome
1615  * @srcs - (struct page *) array of size sh->disks
1616  * @offs - (unsigned int) array of offset for each page
1617  * @sh - stripe_head to parse
1618  *
1619  * Populates srcs in proper layout order for the stripe and returns the
1620  * 'count' of sources to be used in a call to async_gen_syndrome.  The P
1621  * destination buffer is recorded in srcs[count] and the Q destination
1622  * is recorded in srcs[count+1]].
1623  */
1624 static int set_syndrome_sources(struct page **srcs,
1625                 unsigned int *offs,
1626                 struct stripe_head *sh,
1627                 int srctype)
1628 {
1629     int disks = sh->disks;
1630     int syndrome_disks = sh->ddf_layout ? disks : (disks - 2);
1631     int d0_idx = raid6_d0(sh);
1632     int count;
1633     int i;
1634
1635     for (i = 0; i < disks; i++)
1636         srcs[i] = NULL;
1637
1638     count = 0;
1639     i = d0_idx;
1640     do {
1641         int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks);
1642         struct r5dev *dev = &sh->dev[i];
1643
1644         if (i == sh->qd_idx || i == sh->pd_idx ||
1645             (srctype == SYNDROME_SRC_ALL) ||
1646             (srctype == SYNDROME_SRC_WANT_DRAIN &&
1647              (test_bit(R5_Wantdrain, &dev->flags) ||
1648               test_bit(R5_InJournal, &dev->flags))) ||
1649             (srctype == SYNDROME_SRC_WRITTEN &&
1650              (dev->written ||
1651               test_bit(R5_InJournal, &dev->flags)))) {
1652             if (test_bit(R5_InJournal, &dev->flags))
1653                 srcs[slot] = sh->dev[i].orig_page;
1654             else
1655                 srcs[slot] = sh->dev[i].page;
1656             /*
1657              * For R5_InJournal, PAGE_SIZE must be 4KB and will
1658              * not shared page. In that case, dev[i].offset
1659              * is 0.
1660              */
1661             offs[slot] = sh->dev[i].offset;
1662         }
1663         i = raid6_next_disk(i, disks);
1664     } while (i != d0_idx);
1665
1666     return syndrome_disks;
1667 }
1668
1669 static struct dma_async_tx_descriptor *
1670 ops_run_compute6_1(struct stripe_head *sh, struct raid5_percpu *percpu)
1671 {
1672     int disks = sh->disks;
1673     struct page **blocks = to_addr_page(percpu, 0);
1674     unsigned int *offs = to_addr_offs(sh, percpu);
1675     int target;
1676     int qd_idx = sh->qd_idx;
1677     struct dma_async_tx_descriptor *tx;
1678     struct async_submit_ctl submit;
1679     struct r5dev *tgt;
1680     struct page *dest;
1681     unsigned int dest_off;
1682     int i;
1683     int count;
1684
1685     BUG_ON(sh->batch_head);
1686     if (sh->ops.target < 0)
1687         target = sh->ops.target2;
1688     else if (sh->ops.target2 < 0)
1689         target = sh->ops.target;
1690     else
1691         /* we should only have one valid target */
1692         BUG();
1693     BUG_ON(target < 0);
1694     pr_debug("%s: stripe %llu block: %d\n",
1695         __func__, (unsigned long long)sh->sector, target);
1696
1697     tgt = &sh->dev[target];
1698     BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1699     dest = tgt->page;
1700     dest_off = tgt->offset;
1701
1702     atomic_inc(&sh->count);
1703
1704     if (target == qd_idx) {
1705         count = set_syndrome_sources(blocks, offs, sh, SYNDROME_SRC_ALL);
1706         blocks[count] = NULL; /* regenerating p is not necessary */
1707         BUG_ON(blocks[count+1] != dest); /* q should already be set */
1708         init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
1709                   ops_complete_compute, sh,
1710                   to_addr_conv(sh, percpu, 0));
1711         tx = async_gen_syndrome(blocks, offs, count+2,
1712                 RAID5_STRIPE_SIZE(sh->raid_conf), &submit);
1713     } else {
1714         /* Compute any data- or p-drive using XOR */
1715         count = 0;
1716         for (i = disks; i-- ; ) {
1717             if (i == target || i == qd_idx)
1718                 continue;
1719             offs[count] = sh->dev[i].offset;
1720             blocks[count++] = sh->dev[i].page;
1721         }
1722
1723         init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST,
1724                   NULL, ops_complete_compute, sh,
1725                   to_addr_conv(sh, percpu, 0));
1726         tx = async_xor_offs(dest, dest_off, blocks, offs, count,
1727                 RAID5_STRIPE_SIZE(sh->raid_conf), &submit);
1728     }
1729
1730     return tx;
1731 }
1732
1733 static struct dma_async_tx_descriptor *
1734 ops_run_compute6_2(struct stripe_head *sh, struct raid5_percpu *percpu)
1735 {
1736     int i, count, disks = sh->disks;
1737     int syndrome_disks = sh->ddf_layout ? disks : disks-2;
1738     int d0_idx = raid6_d0(sh);
1739     int faila = -1, failb = -1;
1740     int target = sh->ops.target;
1741     int target2 = sh->ops.target2;
1742     struct r5dev *tgt = &sh->dev[target];
1743     struct r5dev *tgt2 = &sh->dev[target2];
1744     struct dma_async_tx_descriptor *tx;
1745     struct page **blocks = to_addr_page(percpu, 0);
1746     unsigned int *offs = to_addr_offs(sh, percpu);
1747     struct async_submit_ctl submit;
1748
1749     BUG_ON(sh->batch_head);
1750     pr_debug("%s: stripe %llu block1: %d block2: %d\n",
1751          __func__, (unsigned long long)sh->sector, target, target2);
1752     BUG_ON(target < 0 || target2 < 0);
1753     BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1754     BUG_ON(!test_bit(R5_Wantcompute, &tgt2->flags));
1755
1756     /* we need to open-code set_syndrome_sources to handle the
1757      * slot number conversion for 'faila' and 'failb'
1758      */
1759     for (i = 0; i < disks ; i++) {
1760         offs[i] = 0;
1761         blocks[i] = NULL;
1762     }
1763     count = 0;
1764     i = d0_idx;
1765     do {
1766         int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks);
1767
1768         offs[slot] = sh->dev[i].offset;
1769         blocks[slot] = sh->dev[i].page;
1770
1771         if (i == target)
1772             faila = slot;
1773         if (i == target2)
1774             failb = slot;
1775         i = raid6_next_disk(i, disks);
1776     } while (i != d0_idx);
1777
1778     BUG_ON(faila == failb);
1779     if (failb < faila)
1780         swap(faila, failb);
1781     pr_debug("%s: stripe: %llu faila: %d failb: %d\n",
1782          __func__, (unsigned long long)sh->sector, faila, failb);
1783
1784     atomic_inc(&sh->count);
1785
1786     if (failb == syndrome_disks+1) {
1787         /* Q disk is one of the missing disks */
1788         if (faila == syndrome_disks) {
1789             /* Missing P+Q, just recompute */
1790             init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
1791                       ops_complete_compute, sh,
1792                       to_addr_conv(sh, percpu, 0));
1793             return async_gen_syndrome(blocks, offs, syndrome_disks+2,
1794                           RAID5_STRIPE_SIZE(sh->raid_conf),
1795                           &submit);
1796         } else {
1797             struct page *dest;
1798             unsigned int dest_off;
1799             int data_target;
1800             int qd_idx = sh->qd_idx;
1801
1802             /* Missing D+Q: recompute D from P, then recompute Q */
1803             if (target == qd_idx)
1804                 data_target = target2;
1805             else
1806                 data_target = target;
1807
1808             count = 0;
1809             for (i = disks; i-- ; ) {
1810                 if (i == data_target || i == qd_idx)
1811                     continue;
1812                 offs[count] = sh->dev[i].offset;
1813                 blocks[count++] = sh->dev[i].page;
1814             }
1815             dest = sh->dev[data_target].page;
1816             dest_off = sh->dev[data_target].offset;
1817             init_async_submit(&submit,
1818                       ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST,
1819                       NULL, NULL, NULL,
1820                       to_addr_conv(sh, percpu, 0));
1821             tx = async_xor_offs(dest, dest_off, blocks, offs, count,
1822                        RAID5_STRIPE_SIZE(sh->raid_conf),
1823                        &submit);
1824
1825             count = set_syndrome_sources(blocks, offs, sh, SYNDROME_SRC_ALL);
1826             init_async_submit(&submit, ASYNC_TX_FENCE, tx,
1827                       ops_complete_compute, sh,
1828                       to_addr_conv(sh, percpu, 0));
1829             return async_gen_syndrome(blocks, offs, count+2,
1830                           RAID5_STRIPE_SIZE(sh->raid_conf),
1831                           &submit);
1832         }
1833     } else {
1834         init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
1835                   ops_complete_compute, sh,
1836                   to_addr_conv(sh, percpu, 0));
1837         if (failb == syndrome_disks) {
1838             /* We're missing D+P. */
1839             return async_raid6_datap_recov(syndrome_disks+2,
1840                         RAID5_STRIPE_SIZE(sh->raid_conf),
1841                         faila,
1842                         blocks, offs, &submit);
1843         } else {
1844             /* We're missing D+D. */
1845             return async_raid6_2data_recov(syndrome_disks+2,
1846                         RAID5_STRIPE_SIZE(sh->raid_conf),
1847                         faila, failb,
1848                         blocks, offs, &submit);
1849         }
1850     }
1851 }
1852
1853 static void ops_complete_prexor(void *stripe_head_ref)
1854 {
1855     struct stripe_head *sh = stripe_head_ref;
1856
1857     pr_debug("%s: stripe %llu\n", __func__,
1858         (unsigned long long)sh->sector);
1859
1860     if (r5c_is_writeback(sh->raid_conf->log))
1861         /*
1862          * raid5-cache write back uses orig_page during prexor.
1863          * After prexor, it is time to free orig_page
1864          */
1865         r5c_release_extra_page(sh);
1866 }
1867
1868 static struct dma_async_tx_descriptor *
1869 ops_run_prexor5(struct stripe_head *sh, struct raid5_percpu *percpu,
1870         struct dma_async_tx_descriptor *tx)
1871 {
1872     int disks = sh->disks;
1873     struct page **xor_srcs = to_addr_page(percpu, 0);
1874     unsigned int *off_srcs = to_addr_offs(sh, percpu);
1875     int count = 0, pd_idx = sh->pd_idx, i;
1876     struct async_submit_ctl submit;
1877
1878     /* existing parity data subtracted */
1879     unsigned int off_dest = off_srcs[count] = sh->dev[pd_idx].offset;
1880     struct page *xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page;
1881
1882     BUG_ON(sh->batch_head);
1883     pr_debug("%s: stripe %llu\n", __func__,
1884         (unsigned long long)sh->sector);
1885
1886     for (i = disks; i--; ) {
1887         struct r5dev *dev = &sh->dev[i];
1888         /* Only process blocks that are known to be uptodate */
1889         if (test_bit(R5_InJournal, &dev->flags)) {
1890             /*
1891              * For this case, PAGE_SIZE must be equal to 4KB and
1892              * page offset is zero.
1893              */
1894             off_srcs[count] = dev->offset;
1895             xor_srcs[count++] = dev->orig_page;
1896         } else if (test_bit(R5_Wantdrain, &dev->flags)) {
1897             off_srcs[count] = dev->offset;
1898             xor_srcs[count++] = dev->page;
1899         }
1900     }
1901
1902     init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx,
1903               ops_complete_prexor, sh, to_addr_conv(sh, percpu, 0));
1904     tx = async_xor_offs(xor_dest, off_dest, xor_srcs, off_srcs, count,
1905             RAID5_STRIPE_SIZE(sh->raid_conf), &submit);
1906
1907     return tx;
1908 }
1909
1910 static struct dma_async_tx_descriptor *
1911 ops_run_prexor6(struct stripe_head *sh, struct raid5_percpu *percpu,
1912         struct dma_async_tx_descriptor *tx)
1913 {
1914     struct page **blocks = to_addr_page(percpu, 0);
1915     unsigned int *offs = to_addr_offs(sh, percpu);
1916     int count;
1917     struct async_submit_ctl submit;
1918
1919     pr_debug("%s: stripe %llu\n", __func__,
1920         (unsigned long long)sh->sector);
1921
1922     count = set_syndrome_sources(blocks, offs, sh, SYNDROME_SRC_WANT_DRAIN);
1923
1924     init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_PQ_XOR_DST, tx,
1925               ops_complete_prexor, sh, to_addr_conv(sh, percpu, 0));
1926     tx = async_gen_syndrome(blocks, offs, count+2,
1927             RAID5_STRIPE_SIZE(sh->raid_conf), &submit);
1928
1929     return tx;
1930 }
1931
1932 static struct dma_async_tx_descriptor *
1933 ops_run_biodrain(struct stripe_head *sh, struct dma_async_tx_descriptor *tx)
1934 {
1935     struct r5conf *conf = sh->raid_conf;
1936     int disks = sh->disks;
1937     int i;
1938     struct stripe_head *head_sh = sh;
1939
1940     pr_debug("%s: stripe %llu\n", __func__,
1941         (unsigned long long)sh->sector);
1942
1943     for (i = disks; i--; ) {
1944         struct r5dev *dev;
1945         struct bio *chosen;
1946
1947         sh = head_sh;
1948         if (test_and_clear_bit(R5_Wantdrain, &head_sh->dev[i].flags)) {
1949             struct bio *wbi;
1950
1951 again:
1952             dev = &sh->dev[i];
1953             /*
1954              * clear R5_InJournal, so when rewriting a page in
1955              * journal, it is not skipped by r5l_log_stripe()
1956              */
1957             clear_bit(R5_InJournal, &dev->flags);
1958             spin_lock_irq(&sh->stripe_lock);
1959             chosen = dev->towrite;
1960             dev->towrite = NULL;
1961             sh->overwrite_disks = 0;
1962             BUG_ON(dev->written);
1963             wbi = dev->written = chosen;
1964             spin_unlock_irq(&sh->stripe_lock);
1965             WARN_ON(dev->page != dev->orig_page);
1966
1967             while (wbi && wbi->bi_iter.bi_sector <
1968                 dev->sector + RAID5_STRIPE_SECTORS(conf)) {
1969                 if (wbi->bi_opf & REQ_FUA)
1970                     set_bit(R5_WantFUA, &dev->flags);
1971                 if (wbi->bi_opf & REQ_SYNC)
1972                     set_bit(R5_SyncIO, &dev->flags);
1973                 if (bio_op(wbi) == REQ_OP_DISCARD)
1974                     set_bit(R5_Discard, &dev->flags);
1975                 else {
1976                     tx = async_copy_data(1, wbi, &dev->page,
1977                                  dev->offset,
1978                                  dev->sector, tx, sh,
1979                                  r5c_is_writeback(conf->log));
1980                     if (dev->page != dev->orig_page &&
1981                         !r5c_is_writeback(conf->log)) {
1982                         set_bit(R5_SkipCopy, &dev->flags);
1983                         clear_bit(R5_UPTODATE, &dev->flags);
1984                         clear_bit(R5_OVERWRITE, &dev->flags);
1985                     }
1986                 }
1987                 wbi = r5_next_bio(conf, wbi, dev->sector);
1988             }
1989
1990             if (head_sh->batch_head) {
1991                 sh = list_first_entry(&sh->batch_list,
1992                               struct stripe_head,
1993                               batch_list);
1994                 if (sh == head_sh)
1995                     continue;
1996                 goto again;
1997             }
1998         }
1999     }
2000
2001     return tx;
2002 }
2003
2004 static void ops_complete_reconstruct(void *stripe_head_ref)
2005 {
2006     struct stripe_head *sh = stripe_head_ref;
2007     int disks = sh->disks;
2008     int pd_idx = sh->pd_idx;
2009     int qd_idx = sh->qd_idx;
2010     int i;
2011     bool fua = false, sync = false, discard = false;
2012
2013     pr_debug("%s: stripe %llu\n", __func__,
2014         (unsigned long long)sh->sector);
2015
2016     for (i = disks; i--; ) {
2017         fua |= test_bit(R5_WantFUA, &sh->dev[i].flags);
2018         sync |= test_bit(R5_SyncIO, &sh->dev[i].flags);
2019         discard |= test_bit(R5_Discard, &sh->dev[i].flags);
2020     }
2021
2022     for (i = disks; i--; ) {
2023         struct r5dev *dev = &sh->dev[i];
2024
2025         if (dev->written || i == pd_idx || i == qd_idx) {
2026             if (!discard && !test_bit(R5_SkipCopy, &dev->flags)) {
2027                 set_bit(R5_UPTODATE, &dev->flags);
2028                 if (test_bit(STRIPE_EXPAND_READY, &sh->state))
2029                     set_bit(R5_Expanded, &dev->flags);
2030             }
2031             if (fua)
2032                 set_bit(R5_WantFUA, &dev->flags);
2033             if (sync)
2034                 set_bit(R5_SyncIO, &dev->flags);
2035         }
2036     }
2037
2038     if (sh->reconstruct_state == reconstruct_state_drain_run)
2039         sh->reconstruct_state = reconstruct_state_drain_result;
2040     else if (sh->reconstruct_state == reconstruct_state_prexor_drain_run)
2041         sh->reconstruct_state = reconstruct_state_prexor_drain_result;
2042     else {
2043         BUG_ON(sh->reconstruct_state != reconstruct_state_run);
2044         sh->reconstruct_state = reconstruct_state_result;
2045     }
2046
2047     set_bit(STRIPE_HANDLE, &sh->state);
2048     raid5_release_stripe(sh);
2049 }
2050
2051 static void
2052 ops_run_reconstruct5(struct stripe_head *sh, struct raid5_percpu *percpu,
2053              struct dma_async_tx_descriptor *tx)
2054 {
2055     int disks = sh->disks;
2056     struct page **xor_srcs;
2057     unsigned int *off_srcs;
2058     struct async_submit_ctl submit;
2059     int count, pd_idx = sh->pd_idx, i;
2060     struct page *xor_dest;
2061     unsigned int off_dest;
2062     int prexor = 0;
2063     unsigned long flags;
2064     int j = 0;
2065     struct stripe_head *head_sh = sh;
2066     int last_stripe;
2067
2068     pr_debug("%s: stripe %llu\n", __func__,
2069         (unsigned long long)sh->sector);
2070
2071     for (i = 0; i < sh->disks; i++) {
2072         if (pd_idx == i)
2073             continue;
2074         if (!test_bit(R5_Discard, &sh->dev[i].flags))
2075             break;
2076     }
2077     if (i >= sh->disks) {
2078         atomic_inc(&sh->count);
2079         set_bit(R5_Discard, &sh->dev[pd_idx].flags);
2080         ops_complete_reconstruct(sh);
2081         return;
2082     }
2083 again:
2084     count = 0;
2085     xor_srcs = to_addr_page(percpu, j);
2086     off_srcs = to_addr_offs(sh, percpu);
2087     /* check if prexor is active which means only process blocks
2088      * that are part of a read-modify-write (written)
2089      */
2090     if (head_sh->reconstruct_state == reconstruct_state_prexor_drain_run) {
2091         prexor = 1;
2092         off_dest = off_srcs[count] = sh->dev[pd_idx].offset;
2093         xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page;
2094         for (i = disks; i--; ) {
2095             struct r5dev *dev = &sh->dev[i];
2096             if (head_sh->dev[i].written ||
2097                 test_bit(R5_InJournal, &head_sh->dev[i].flags)) {
2098                 off_srcs[count] = dev->offset;
2099                 xor_srcs[count++] = dev->page;
2100             }
2101         }
2102     } else {
2103         xor_dest = sh->dev[pd_idx].page;
2104         off_dest = sh->dev[pd_idx].offset;
2105         for (i = disks; i--; ) {
2106             struct r5dev *dev = &sh->dev[i];
2107             if (i != pd_idx) {
2108                 off_srcs[count] = dev->offset;
2109                 xor_srcs[count++] = dev->page;
2110             }
2111         }
2112     }
2113
2114     /* 1/ if we prexor'd then the dest is reused as a source
2115      * 2/ if we did not prexor then we are redoing the parity
2116      * set ASYNC_TX_XOR_DROP_DST and ASYNC_TX_XOR_ZERO_DST
2117      * for the synchronous xor case
2118      */
2119     last_stripe = !head_sh->batch_head ||
2120         list_first_entry(&sh->batch_list,
2121                  struct stripe_head, batch_list) == head_sh;
2122     if (last_stripe) {
2123         flags = ASYNC_TX_ACK |
2124             (prexor ? ASYNC_TX_XOR_DROP_DST : ASYNC_TX_XOR_ZERO_DST);
2125
2126         atomic_inc(&head_sh->count);
2127         init_async_submit(&submit, flags, tx, ops_complete_reconstruct, head_sh,
2128                   to_addr_conv(sh, percpu, j));
2129     } else {
2130         flags = prexor ? ASYNC_TX_XOR_DROP_DST : ASYNC_TX_XOR_ZERO_DST;
2131         init_async_submit(&submit, flags, tx, NULL, NULL,
2132                   to_addr_conv(sh, percpu, j));
2133     }
2134
2135     if (unlikely(count == 1))
2136         tx = async_memcpy(xor_dest, xor_srcs[0], off_dest, off_srcs[0],
2137                 RAID5_STRIPE_SIZE(sh->raid_conf), &submit);
2138     else
2139         tx = async_xor_offs(xor_dest, off_dest, xor_srcs, off_srcs, count,
2140                 RAID5_STRIPE_SIZE(sh->raid_conf), &submit);
2141     if (!last_stripe) {
2142         j++;
2143         sh = list_first_entry(&sh->batch_list, struct stripe_head,
2144                       batch_list);
2145         goto again;
2146     }
2147 }
2148
2149 static void
2150 ops_run_reconstruct6(struct stripe_head *sh, struct raid5_percpu *percpu,
2151              struct dma_async_tx_descriptor *tx)
2152 {
2153     struct async_submit_ctl submit;
2154     struct page **blocks;
2155     unsigned int *offs;
2156     int count, i, j = 0;
2157     struct stripe_head *head_sh = sh;
2158     int last_stripe;
2159     int synflags;
2160     unsigned long txflags;
2161
2162     pr_debug("%s: stripe %llu\n", __func__, (unsigned long long)sh->sector);
2163
2164     for (i = 0; i < sh->disks; i++) {
2165         if (sh->pd_idx == i || sh->qd_idx == i)
2166             continue;
2167         if (!test_bit(R5_Discard, &sh->dev[i].flags))
2168             break;
2169     }
2170     if (i >= sh->disks) {
2171         atomic_inc(&sh->count);
2172         set_bit(R5_Discard, &sh->dev[sh->pd_idx].flags);
2173         set_bit(R5_Discard, &sh->dev[sh->qd_idx].flags);
2174         ops_complete_reconstruct(sh);
2175         return;
2176     }
2177
2178 again:
2179     blocks = to_addr_page(percpu, j);
2180     offs = to_addr_offs(sh, percpu);
2181
2182     if (sh->reconstruct_state == reconstruct_state_prexor_drain_run) {
2183         synflags = SYNDROME_SRC_WRITTEN;
2184         txflags = ASYNC_TX_ACK | ASYNC_TX_PQ_XOR_DST;
2185     } else {
2186         synflags = SYNDROME_SRC_ALL;
2187         txflags = ASYNC_TX_ACK;
2188     }
2189
2190     count = set_syndrome_sources(blocks, offs, sh, synflags);
2191     last_stripe = !head_sh->batch_head ||
2192         list_first_entry(&sh->batch_list,
2193                  struct stripe_head, batch_list) == head_sh;
2194
2195     if (last_stripe) {
2196         atomic_inc(&head_sh->count);
2197         init_async_submit(&submit, txflags, tx, ops_complete_reconstruct,
2198                   head_sh, to_addr_conv(sh, percpu, j));
2199     } else
2200         init_async_submit(&submit, 0, tx, NULL, NULL,
2201                   to_addr_conv(sh, percpu, j));
2202     tx = async_gen_syndrome(blocks, offs, count+2,
2203             RAID5_STRIPE_SIZE(sh->raid_conf),  &submit);
2204     if (!last_stripe) {
2205         j++;
2206         sh = list_first_entry(&sh->batch_list, struct stripe_head,
2207                       batch_list);
2208         goto again;
2209     }
2210 }
2211
2212 static void ops_complete_check(void *stripe_head_ref)
2213 {
2214     struct stripe_head *sh = stripe_head_ref;
2215
2216     pr_debug("%s: stripe %llu\n", __func__,
2217         (unsigned long long)sh->sector);
2218
2219     sh->check_state = check_state_check_result;
2220     set_bit(STRIPE_HANDLE, &sh->state);
2221     raid5_release_stripe(sh);
2222 }
2223
2224 static void ops_run_check_p(struct stripe_head *sh, struct raid5_percpu *percpu)
2225 {
2226     int disks = sh->disks;
2227     int pd_idx = sh->pd_idx;
2228     int qd_idx = sh->qd_idx;
2229     struct page *xor_dest;
2230     unsigned int off_dest;
2231     struct page **xor_srcs = to_addr_page(percpu, 0);
2232     unsigned int *off_srcs = to_addr_offs(sh, percpu);
2233     struct dma_async_tx_descriptor *tx;
2234     struct async_submit_ctl submit;
2235     int count;
2236     int i;
2237
2238     pr_debug("%s: stripe %llu\n", __func__,
2239         (unsigned long long)sh->sector);
2240
2241     BUG_ON(sh->batch_head);
2242     count = 0;
2243     xor_dest = sh->dev[pd_idx].page;
2244     off_dest = sh->dev[pd_idx].offset;
2245     off_srcs[count] = off_dest;
2246     xor_srcs[count++] = xor_dest;
2247     for (i = disks; i--; ) {
2248         if (i == pd_idx || i == qd_idx)
2249             continue;
2250         off_srcs[count] = sh->dev[i].offset;
2251         xor_srcs[count++] = sh->dev[i].page;
2252     }
2253
2254     init_async_submit(&submit, 0, NULL, NULL, NULL,
2255               to_addr_conv(sh, percpu, 0));
2256     tx = async_xor_val_offs(xor_dest, off_dest, xor_srcs, off_srcs, count,
2257                RAID5_STRIPE_SIZE(sh->raid_conf),
2258                &sh->ops.zero_sum_result, &submit);
2259
2260     atomic_inc(&sh->count);
2261     init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_check, sh, NULL);
2262     tx = async_trigger_callback(&submit);
2263 }
2264
2265 static void ops_run_check_pq(struct stripe_head *sh, struct raid5_percpu *percpu, int checkp)
2266 {
2267     struct page **srcs = to_addr_page(percpu, 0);
2268     unsigned int *offs = to_addr_offs(sh, percpu);
2269     struct async_submit_ctl submit;
2270     int count;
2271
2272     pr_debug("%s: stripe %llu checkp: %d\n", __func__,
2273         (unsigned long long)sh->sector, checkp);
2274
2275     BUG_ON(sh->batch_head);
2276     count = set_syndrome_sources(srcs, offs, sh, SYNDROME_SRC_ALL);
2277     if (!checkp)
2278         srcs[count] = NULL;
2279
2280     atomic_inc(&sh->count);
2281     init_async_submit(&submit, ASYNC_TX_ACK, NULL, ops_complete_check,
2282               sh, to_addr_conv(sh, percpu, 0));
2283     async_syndrome_val(srcs, offs, count+2,
2284                RAID5_STRIPE_SIZE(sh->raid_conf),
2285                &sh->ops.zero_sum_result, percpu->spare_page, 0, &submit);
2286 }
2287
2288 static void raid_run_ops(struct stripe_head *sh, unsigned long ops_request)
2289 {
2290     int overlap_clear = 0, i, disks = sh->disks;
2291     struct dma_async_tx_descriptor *tx = NULL;
2292     struct r5conf *conf = sh->raid_conf;
2293     int level = conf->level;
2294     struct raid5_percpu *percpu;
2295
2296     local_lock(&conf->percpu->lock);
2297     percpu = this_cpu_ptr(conf->percpu);
2298     if (test_bit(STRIPE_OP_BIOFILL, &ops_request)) {
2299         ops_run_biofill(sh);
2300         overlap_clear++;
2301     }
2302
2303     if (test_bit(STRIPE_OP_COMPUTE_BLK, &ops_request)) {
2304         if (level < 6)
2305             tx = ops_run_compute5(sh, percpu);
2306         else {
2307             if (sh->ops.target2 < 0 || sh->ops.target < 0)
2308                 tx = ops_run_compute6_1(sh, percpu);
2309             else
2310                 tx = ops_run_compute6_2(sh, percpu);
2311         }
2312         /* terminate the chain if reconstruct is not set to be run */
2313         if (tx && !test_bit(STRIPE_OP_RECONSTRUCT, &ops_request))
2314             async_tx_ack(tx);
2315     }
2316
2317     if (test_bit(STRIPE_OP_PREXOR, &ops_request)) {
2318         if (level < 6)
2319             tx = ops_run_prexor5(sh, percpu, tx);
2320         else
2321             tx = ops_run_prexor6(sh, percpu, tx);
2322     }
2323
2324     if (test_bit(STRIPE_OP_PARTIAL_PARITY, &ops_request))
2325         tx = ops_run_partial_parity(sh, percpu, tx);
2326
2327     if (test_bit(STRIPE_OP_BIODRAIN, &ops_request)) {
2328         tx = ops_run_biodrain(sh, tx);
2329         overlap_clear++;
2330     }
2331
2332     if (test_bit(STRIPE_OP_RECONSTRUCT, &ops_request)) {
2333         if (level < 6)
2334             ops_run_reconstruct5(sh, percpu, tx);
2335         else
2336             ops_run_reconstruct6(sh, percpu, tx);
2337     }
2338
2339     if (test_bit(STRIPE_OP_CHECK, &ops_request)) {
2340         if (sh->check_state == check_state_run)
2341             ops_run_check_p(sh, percpu);
2342         else if (sh->check_state == check_state_run_q)
2343             ops_run_check_pq(sh, percpu, 0);
2344         else if (sh->check_state == check_state_run_pq)
2345             ops_run_check_pq(sh, percpu, 1);
2346         else
2347             BUG();
2348     }
2349
2350     if (overlap_clear && !sh->batch_head) {
2351         for (i = disks; i--; ) {
2352             struct r5dev *dev = &sh->dev[i];
2353             if (test_and_clear_bit(R5_Overlap, &dev->flags))
2354                 wake_up(&sh->raid_conf->wait_for_overlap);
2355         }
2356     }
2357     local_unlock(&conf->percpu->lock);
2358 }
2359
2360 static void free_stripe(struct kmem_cache *sc, struct stripe_head *sh)
2361 {
2362 #if PAGE_SIZE != DEFAULT_STRIPE_SIZE
2363     kfree(sh->pages);
2364 #endif
2365     if (sh->ppl_page)
2366         __free_page(sh->ppl_page);
2367     kmem_cache_free(sc, sh);
2368 }
2369
2370 static struct stripe_head *alloc_stripe(struct kmem_cache *sc, gfp_t gfp,
2371     int disks, struct r5conf *conf)
2372 {
2373     struct stripe_head *sh;
2374
2375     sh = kmem_cache_zalloc(sc, gfp);
2376     if (sh) {
2377         spin_lock_init(&sh->stripe_lock);
2378         spin_lock_init(&sh->batch_lock);
2379         INIT_LIST_HEAD(&sh->batch_list);
2380         INIT_LIST_HEAD(&sh->lru);
2381         INIT_LIST_HEAD(&sh->r5c);
2382         INIT_LIST_HEAD(&sh->log_list);
2383         atomic_set(&sh->count, 1);
2384         sh->raid_conf = conf;
2385         sh->log_start = MaxSector;
2386
2387         if (raid5_has_ppl(conf)) {
2388             sh->ppl_page = alloc_page(gfp);
2389             if (!sh->ppl_page) {
2390                 free_stripe(sc, sh);
2391                 return NULL;
2392             }
2393         }
2394 #if PAGE_SIZE != DEFAULT_STRIPE_SIZE
2395         if (init_stripe_shared_pages(sh, conf, disks)) {
2396             free_stripe(sc, sh);
2397             return NULL;
2398         }
2399 #endif
2400     }
2401     return sh;
2402 }
2403 static int grow_one_stripe(struct r5conf *conf, gfp_t gfp)
2404 {
2405     struct stripe_head *sh;
2406
2407     sh = alloc_stripe(conf->slab_cache, gfp, conf->pool_size, conf);
2408     if (!sh)
2409         return 0;
2410
2411     if (grow_buffers(sh, gfp)) {
2412         shrink_buffers(sh);
2413         free_stripe(conf->slab_cache, sh);
2414         return 0;
2415     }
2416     sh->hash_lock_index =
2417         conf->max_nr_stripes % NR_STRIPE_HASH_LOCKS;
2418     /* we just created an active stripe so... */
2419     atomic_inc(&conf->active_stripes);
2420
2421     raid5_release_stripe(sh);
2422     conf->max_nr_stripes++;
2423     return 1;
2424 }
2425
2426 static int grow_stripes(struct r5conf *conf, int num)
2427 {
2428     struct kmem_cache *sc;
2429     size_t namelen = sizeof(conf->cache_name[0]);
2430     int devs = max(conf->raid_disks, conf->previous_raid_disks);
2431
2432     if (conf->mddev->gendisk)
2433         snprintf(conf->cache_name[0], namelen,
2434             "raid%d-%s", conf->level, mdname(conf->mddev));
2435     else
2436         snprintf(conf->cache_name[0], namelen,
2437             "raid%d-%p", conf->level, conf->mddev);
2438     snprintf(conf->cache_name[1], namelen, "%.27s-alt", conf->cache_name[0]);
2439
2440     conf->active_name = 0;
2441     sc = kmem_cache_create(conf->cache_name[conf->active_name],
2442                    sizeof(struct stripe_head)+(devs-1)*sizeof(struct r5dev),
2443                    0, 0, NULL);
2444     if (!sc)
2445         return 1;
2446     conf->slab_cache = sc;
2447     conf->pool_size = devs;
2448     while (num--)
2449         if (!grow_one_stripe(conf, GFP_KERNEL))
2450             return 1;
2451
2452     return 0;
2453 }
2454
2455 /**
2456  * scribble_alloc - allocate percpu scribble buffer for required size
2457  *          of the scribble region
2458  * @percpu: from for_each_present_cpu() of the caller
2459  * @num: total number of disks in the array
2460  * @cnt: scribble objs count for required size of the scribble region
2461  *
2462  * The scribble buffer size must be enough to contain:
2463  * 1/ a struct page pointer for each device in the array +2
2464  * 2/ room to convert each entry in (1) to its corresponding dma
2465  *    (dma_map_page()) or page (page_address()) address.
2466  *
2467  * Note: the +2 is for the destination buffers of the ddf/raid6 case where we
2468  * calculate over all devices (not just the data blocks), using zeros in place
2469  * of the P and Q blocks.
2470  */
2471 static int scribble_alloc(struct raid5_percpu *percpu,
2472               int num, int cnt)
2473 {
2474     size_t obj_size =
2475         sizeof(struct page *) * (num + 2) +
2476         sizeof(addr_conv_t) * (num + 2) +
2477         sizeof(unsigned int) * (num + 2);
2478     void *scribble;
2479
2480     /*
2481      * If here is in raid array suspend context, it is in memalloc noio
2482      * context as well, there is no potential recursive memory reclaim
2483      * I/Os with the GFP_KERNEL flag.
2484      */
2485     scribble = kvmalloc_array(cnt, obj_size, GFP_KERNEL);
2486     if (!scribble)
2487         return -ENOMEM;
2488
2489     kvfree(percpu->scribble);
2490
2491     percpu->scribble = scribble;
2492     percpu->scribble_obj_size = obj_size;
2493     return 0;
2494 }
2495
2496 static int resize_chunks(struct r5conf *conf, int new_disks, int new_sectors)
2497 {
2498     unsigned long cpu;
2499     int err = 0;
2500
2501     /*
2502      * Never shrink. And mddev_suspend() could deadlock if this is called
2503      * from raid5d. In that case, scribble_disks and scribble_sectors
2504      * should equal to new_disks and new_sectors
2505      */
2506     if (conf->scribble_disks >= new_disks &&
2507         conf->scribble_sectors >= new_sectors)
2508         return 0;
2509     mddev_suspend(conf->mddev);
2510     cpus_read_lock();
2511
2512     for_each_present_cpu(cpu) {
2513         struct raid5_percpu *percpu;
2514
2515         percpu = per_cpu_ptr(conf->percpu, cpu);
2516         err = scribble_alloc(percpu, new_disks,
2517                      new_sectors / RAID5_STRIPE_SECTORS(conf));
2518         if (err)
2519             break;
2520     }
2521
2522     cpus_read_unlock();
2523     mddev_resume(conf->mddev);
2524     if (!err) {
2525         conf->scribble_disks = new_disks;
2526         conf->scribble_sectors = new_sectors;
2527     }
2528     return err;
2529 }
2530
2531 static int resize_stripes(struct r5conf *conf, int newsize)
2532 {
2533     /* Make all the stripes able to hold 'newsize' devices.
2534      * New slots in each stripe get 'page' set to a new page.
2535      *
2536      * This happens in stages:
2537      * 1/ create a new kmem_cache and allocate the required number of
2538      *    stripe_heads.
2539      * 2/ gather all the old stripe_heads and transfer the pages across
2540      *    to the new stripe_heads.  This will have the side effect of
2541      *    freezing the array as once all stripe_heads have been collected,
2542      *    no IO will be possible.  Old stripe heads are freed once their
2543      *    pages have been transferred over, and the old kmem_cache is
2544      *    freed when all stripes are done.
2545      * 3/ reallocate conf->disks to be suitable bigger.  If this fails,
2546      *    we simple return a failure status - no need to clean anything up.
2547      * 4/ allocate new pages for the new slots in the new stripe_heads.
2548      *    If this fails, we don't bother trying the shrink the
2549      *    stripe_heads down again, we just leave them as they are.
2550      *    As each stripe_head is processed the new one is released into
2551      *    active service.
2552      *
2553      * Once step2 is started, we cannot afford to wait for a write,
2554      * so we use GFP_NOIO allocations.
2555      */
2556     struct stripe_head *osh, *nsh;
2557     LIST_HEAD(newstripes);
2558     struct disk_info *ndisks;
2559     int err = 0;
2560     struct kmem_cache *sc;
2561     int i;
2562     int hash, cnt;
2563
2564     md_allow_write(conf->mddev);
2565
2566     /* Step 1 */
2567     sc = kmem_cache_create(conf->cache_name[1-conf->active_name],
2568                    sizeof(struct stripe_head)+(newsize-1)*sizeof(struct r5dev),
2569                    0, 0, NULL);
2570     if (!sc)
2571         return -ENOMEM;
2572
2573     /* Need to ensure auto-resizing doesn't interfere */
2574     mutex_lock(&conf->cache_size_mutex);
2575
2576     for (i = conf->max_nr_stripes; i; i--) {
2577         nsh = alloc_stripe(sc, GFP_KERNEL, newsize, conf);
2578         if (!nsh)
2579             break;
2580
2581         list_add(&nsh->lru, &newstripes);
2582     }
2583     if (i) {
2584         /* didn't get enough, give up */
2585         while (!list_empty(&newstripes)) {
2586             nsh = list_entry(newstripes.next, struct stripe_head, lru);
2587             list_del(&nsh->lru);
2588             free_stripe(sc, nsh);
2589         }
2590         kmem_cache_destroy(sc);
2591         mutex_unlock(&conf->cache_size_mutex);
2592         return -ENOMEM;
2593     }
2594     /* Step 2 - Must use GFP_NOIO now.
2595      * OK, we have enough stripes, start collecting inactive
2596      * stripes and copying them over
2597      */
2598     hash = 0;
2599     cnt = 0;
2600     list_for_each_entry(nsh, &newstripes, lru) {
2601         lock_device_hash_lock(conf, hash);
2602         wait_event_cmd(conf->wait_for_stripe,
2603                     !list_empty(conf->inactive_list + hash),
2604                     unlock_device_hash_lock(conf, hash),
2605                     lock_device_hash_lock(conf, hash));
2606         osh = get_free_stripe(conf, hash);
2607         unlock_device_hash_lock(conf, hash);
2608
2609 #if PAGE_SIZE != DEFAULT_STRIPE_SIZE
2610     for (i = 0; i < osh->nr_pages; i++) {
2611         nsh->pages[i] = osh->pages[i];
2612         osh->pages[i] = NULL;
2613     }
2614 #endif
2615         for(i=0; i<conf->pool_size; i++) {
2616             nsh->dev[i].page = osh->dev[i].page;
2617             nsh->dev[i].orig_page = osh->dev[i].page;
2618             nsh->dev[i].offset = osh->dev[i].offset;
2619         }
2620         nsh->hash_lock_index = hash;
2621         free_stripe(conf->slab_cache, osh);
2622         cnt++;
2623         if (cnt >= conf->max_nr_stripes / NR_STRIPE_HASH_LOCKS +
2624             !!((conf->max_nr_stripes % NR_STRIPE_HASH_LOCKS) > hash)) {
2625             hash++;
2626             cnt = 0;
2627         }
2628     }
2629     kmem_cache_destroy(conf->slab_cache);
2630
2631     /* Step 3.
2632      * At this point, we are holding all the stripes so the array
2633      * is completely stalled, so now is a good time to resize
2634      * conf->disks and the scribble region
2635      */
2636     ndisks = kcalloc(newsize, sizeof(struct disk_info), GFP_NOIO);
2637     if (ndisks) {
2638         for (i = 0; i < conf->pool_size; i++)
2639             ndisks[i] = conf->disks[i];
2640
2641         for (i = conf->pool_size; i < newsize; i++) {
2642             ndisks[i].extra_page = alloc_page(GFP_NOIO);
2643             if (!ndisks[i].extra_page)
2644                 err = -ENOMEM;
2645         }
2646
2647         if (err) {
2648             for (i = conf->pool_size; i < newsize; i++)
2649                 if (ndisks[i].extra_page)
2650                     put_page(ndisks[i].extra_page);
2651             kfree(ndisks);
2652         } else {
2653             kfree(conf->disks);
2654             conf->disks = ndisks;
2655         }
2656     } else
2657         err = -ENOMEM;
2658
2659     conf->slab_cache = sc;
2660     conf->active_name = 1-conf->active_name;
2661
2662     /* Step 4, return new stripes to service */
2663     while(!list_empty(&newstripes)) {
2664         nsh = list_entry(newstripes.next, struct stripe_head, lru);
2665         list_del_init(&nsh->lru);
2666
2667 #if PAGE_SIZE != DEFAULT_STRIPE_SIZE
2668         for (i = 0; i < nsh->nr_pages; i++) {
2669             if (nsh->pages[i])
2670                 continue;
2671             nsh->pages[i] = alloc_page(GFP_NOIO);
2672             if (!nsh->pages[i])
2673                 err = -ENOMEM;
2674         }
2675
2676         for (i = conf->raid_disks; i < newsize; i++) {
2677             if (nsh->dev[i].page)
2678                 continue;
2679             nsh->dev[i].page = raid5_get_dev_page(nsh, i);
2680             nsh->dev[i].orig_page = nsh->dev[i].page;
2681             nsh->dev[i].offset = raid5_get_page_offset(nsh, i);
2682         }
2683 #else
2684         for (i=conf->raid_disks; i < newsize; i++)
2685             if (nsh->dev[i].page == NULL) {
2686                 struct page *p = alloc_page(GFP_NOIO);
2687                 nsh->dev[i].page = p;
2688                 nsh->dev[i].orig_page = p;
2689                 nsh->dev[i].offset = 0;
2690                 if (!p)
2691                     err = -ENOMEM;
2692             }
2693 #endif
2694         raid5_release_stripe(nsh);
2695     }
2696     /* critical section pass, GFP_NOIO no longer needed */
2697
2698     if (!err)
2699         conf->pool_size = newsize;
2700     mutex_unlock(&conf->cache_size_mutex);
2701
2702     return err;
2703 }
2704
2705 static int drop_one_stripe(struct r5conf *conf)
2706 {
2707     struct stripe_head *sh;
2708     int hash = (conf->max_nr_stripes - 1) & STRIPE_HASH_LOCKS_MASK;
2709
2710     spin_lock_irq(conf->hash_locks + hash);
2711     sh = get_free_stripe(conf, hash);
2712     spin_unlock_irq(conf->hash_locks + hash);
2713     if (!sh)
2714         return 0;
2715     BUG_ON(atomic_read(&sh->count));
2716     shrink_buffers(sh);
2717     free_stripe(conf->slab_cache, sh);
2718     atomic_dec(&conf->active_stripes);
2719     conf->max_nr_stripes--;
2720     return 1;
2721 }
2722
2723 static void shrink_stripes(struct r5conf *conf)
2724 {
2725     while (conf->max_nr_stripes &&
2726            drop_one_stripe(conf))
2727         ;
2728
2729     kmem_cache_destroy(conf->slab_cache);
2730     conf->slab_cache = NULL;
2731 }
2732
2733 /*
2734  * This helper wraps rcu_dereference_protected() and can be used when
2735  * it is known that the nr_pending of the rdev is elevated.
2736  */
2737 static struct md_rdev *rdev_pend_deref(struct md_rdev __rcu *rdev)
2738 {
2739     return rcu_dereference_protected(rdev,
2740             atomic_read(&rcu_access_pointer(rdev)->nr_pending));
2741 }
2742
2743 /*
2744  * This helper wraps rcu_dereference_protected() and should be used
2745  * when it is known that the mddev_lock() is held. This is safe
2746  * seeing raid5_remove_disk() has the same lock held.
2747  */
2748 static struct md_rdev *rdev_mdlock_deref(struct mddev *mddev,
2749                      struct md_rdev __rcu *rdev)
2750 {
2751     return rcu_dereference_protected(rdev,
2752             lockdep_is_held(&mddev->reconfig_mutex));
2753 }
2754
2755 static void raid5_end_read_request(struct bio * bi)
2756 {
2757     struct stripe_head *sh = bi->bi_private;
2758     struct r5conf *conf = sh->raid_conf;
2759     int disks = sh->disks, i;
2760     struct md_rdev *rdev = NULL;
2761     sector_t s;
2762
2763     for (i=0 ; i<disks; i++)
2764         if (bi == &sh->dev[i].req)
2765             break;
2766
2767     pr_debug("end_read_request %llu/%d, count: %d, error %d.\n",
2768         (unsigned long long)sh->sector, i, atomic_read(&sh->count),
2769         bi->bi_status);
2770     if (i == disks) {
2771         BUG();
2772         return;
2773     }
2774     if (test_bit(R5_ReadRepl, &sh->dev[i].flags))
2775         /* If replacement finished while this request was outstanding,
2776          * 'replacement' might be NULL already.
2777          * In that case it moved down to 'rdev'.
2778          * rdev is not removed until all requests are finished.
2779          */
2780         rdev = rdev_pend_deref(conf->disks[i].replacement);
2781     if (!rdev)
2782         rdev = rdev_pend_deref(conf->disks[i].rdev);
2783
2784     if (use_new_offset(conf, sh))
2785         s = sh->sector + rdev->new_data_offset;
2786     else
2787         s = sh->sector + rdev->data_offset;
2788     if (!bi->bi_status) {
2789         set_bit(R5_UPTODATE, &sh->dev[i].flags);
2790         if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
2791             /* Note that this cannot happen on a
2792              * replacement device.  We just fail those on
2793              * any error
2794              */
2795             pr_info_ratelimited(
2796                 "md/raid:%s: read error corrected (%lu sectors at %llu on %pg)\n",
2797                 mdname(conf->mddev), RAID5_STRIPE_SECTORS(conf),
2798                 (unsigned long long)s,
2799                 rdev->bdev);
2800             atomic_add(RAID5_STRIPE_SECTORS(conf), &rdev->corrected_errors);
2801             clear_bit(R5_ReadError, &sh->dev[i].flags);
2802             clear_bit(R5_ReWrite, &sh->dev[i].flags);
2803         } else if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags))
2804             clear_bit(R5_ReadNoMerge, &sh->dev[i].flags);
2805
2806         if (test_bit(R5_InJournal, &sh->dev[i].flags))
2807             /*
2808              * end read for a page in journal, this
2809              * must be preparing for prexor in rmw
2810              */
2811             set_bit(R5_OrigPageUPTDODATE, &sh->dev[i].flags);
2812
2813         if (atomic_read(&rdev->read_errors))
2814             atomic_set(&rdev->read_errors, 0);
2815     } else {
2816         int retry = 0;
2817         int set_bad = 0;
2818
2819         clear_bit(R5_UPTODATE, &sh->dev[i].flags);
2820         if (!(bi->bi_status == BLK_STS_PROTECTION))
2821             atomic_inc(&rdev->read_errors);
2822         if (test_bit(R5_ReadRepl, &sh->dev[i].flags))
2823             pr_warn_ratelimited(
2824                 "md/raid:%s: read error on replacement device (sector %llu on %pg).\n",
2825                 mdname(conf->mddev),
2826                 (unsigned long long)s,
2827                 rdev->bdev);
2828         else if (conf->mddev->degraded >= conf->max_degraded) {
2829             set_bad = 1;
2830             pr_warn_ratelimited(
2831                 "md/raid:%s: read error not correctable (sector %llu on %pg).\n",
2832                 mdname(conf->mddev),
2833                 (unsigned long long)s,
2834                 rdev->bdev);
2835         } else if (test_bit(R5_ReWrite, &sh->dev[i].flags)) {
2836             /* Oh, no!!! */
2837             set_bad = 1;
2838             pr_warn_ratelimited(
2839                 "md/raid:%s: read error NOT corrected!! (sector %llu on %pg).\n",
2840                 mdname(conf->mddev),
2841                 (unsigned long long)s,
2842                 rdev->bdev);
2843         } else if (atomic_read(&rdev->read_errors)
2844              > conf->max_nr_stripes) {
2845             if (!test_bit(Faulty, &rdev->flags)) {
2846                 pr_warn("md/raid:%s: %d read_errors > %d stripes\n",
2847                     mdname(conf->mddev),
2848                     atomic_read(&rdev->read_errors),
2849                     conf->max_nr_stripes);
2850                 pr_warn("md/raid:%s: Too many read errors, failing device %pg.\n",
2851                     mdname(conf->mddev), rdev->bdev);
2852             }
2853         } else
2854             retry = 1;
2855         if (set_bad && test_bit(In_sync, &rdev->flags)
2856             && !test_bit(R5_ReadNoMerge, &sh->dev[i].flags))
2857             retry = 1;
2858         if (retry)
2859             if (sh->qd_idx >= 0 && sh->pd_idx == i)
2860                 set_bit(R5_ReadError, &sh->dev[i].flags);
2861             else if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags)) {
2862                 set_bit(R5_ReadError, &sh->dev[i].flags);
2863                 clear_bit(R5_ReadNoMerge, &sh->dev[i].flags);
2864             } else
2865                 set_bit(R5_ReadNoMerge, &sh->dev[i].flags);
2866         else {
2867             clear_bit(R5_ReadError, &sh->dev[i].flags);
2868             clear_bit(R5_ReWrite, &sh->dev[i].flags);
2869             if (!(set_bad
2870                   && test_bit(In_sync, &rdev->flags)
2871                   && rdev_set_badblocks(
2872                       rdev, sh->sector, RAID5_STRIPE_SECTORS(conf), 0)))
2873                 md_error(conf->mddev, rdev);
2874         }
2875     }
2876     rdev_dec_pending(rdev, conf->mddev);
2877     bio_uninit(bi);
2878     clear_bit(R5_LOCKED, &sh->dev[i].flags);
2879     set_bit(STRIPE_HANDLE, &sh->state);
2880     raid5_release_stripe(sh);
2881 }
2882
2883 static void raid5_end_write_request(struct bio *bi)
2884 {
2885     struct stripe_head *sh = bi->bi_private;
2886     struct r5conf *conf = sh->raid_conf;
2887     int disks = sh->disks, i;
2888     struct md_rdev *rdev;
2889     sector_t first_bad;
2890     int bad_sectors;
2891     int replacement = 0;
2892
2893     for (i = 0 ; i < disks; i++) {
2894         if (bi == &sh->dev[i].req) {
2895             rdev = rdev_pend_deref(conf->disks[i].rdev);
2896             break;
2897         }
2898         if (bi == &sh->dev[i].rreq) {
2899             rdev = rdev_pend_deref(conf->disks[i].replacement);
2900             if (rdev)
2901                 replacement = 1;
2902             else
2903                 /* rdev was removed and 'replacement'
2904                  * replaced it.  rdev is not removed
2905                  * until all requests are finished.
2906                  */
2907                 rdev = rdev_pend_deref(conf->disks[i].rdev);
2908             break;
2909         }
2910     }
2911     pr_debug("end_write_request %llu/%d, count %d, error: %d.\n",
2912         (unsigned long long)sh->sector, i, atomic_read(&sh->count),
2913         bi->bi_status);
2914     if (i == disks) {
2915         BUG();
2916         return;
2917     }
2918
2919     if (replacement) {
2920         if (bi->bi_status)
2921             md_error(conf->mddev, rdev);
2922         else if (is_badblock(rdev, sh->sector,
2923                      RAID5_STRIPE_SECTORS(conf),
2924                      &first_bad, &bad_sectors))
2925             set_bit(R5_MadeGoodRepl, &sh->dev[i].flags);
2926     } else {
2927         if (bi->bi_status) {
2928             set_bit(STRIPE_DEGRADED, &sh->state);
2929             set_bit(WriteErrorSeen, &rdev->flags);
2930             set_bit(R5_WriteError, &sh->dev[i].flags);
2931             if (!test_and_set_bit(WantReplacement, &rdev->flags))
2932                 set_bit(MD_RECOVERY_NEEDED,
2933                     &rdev->mddev->recovery);
2934         } else if (is_badblock(rdev, sh->sector,
2935                        RAID5_STRIPE_SECTORS(conf),
2936                        &first_bad, &bad_sectors)) {
2937             set_bit(R5_MadeGood, &sh->dev[i].flags);
2938             if (test_bit(R5_ReadError, &sh->dev[i].flags))
2939                 /* That was a successful write so make
2940                  * sure it looks like we already did
2941                  * a re-write.
2942                  */
2943                 set_bit(R5_ReWrite, &sh->dev[i].flags);
2944         }
2945     }
2946     rdev_dec_pending(rdev, conf->mddev);
2947
2948     if (sh->batch_head && bi->bi_status && !replacement)
2949         set_bit(STRIPE_BATCH_ERR, &sh->batch_head->state);
2950
2951     bio_uninit(bi);
2952     if (!test_and_clear_bit(R5_DOUBLE_LOCKED, &sh->dev[i].flags))
2953         clear_bit(R5_LOCKED, &sh->dev[i].flags);
2954     set_bit(STRIPE_HANDLE, &sh->state);
2955
2956     if (sh->batch_head && sh != sh->batch_head)
2957         raid5_release_stripe(sh->batch_head);
2958     raid5_release_stripe(sh);
2959 }
2960
2961 static void raid5_error(struct mddev *mddev, struct md_rdev *rdev)
2962 {
2963     struct r5conf *conf = mddev->private;
2964     unsigned long flags;
2965     pr_debug("raid456: error called\n");
2966
2967     pr_crit("md/raid:%s: Disk failure on %pg, disabling device.\n",
2968         mdname(mddev), rdev->bdev);
2969
2970     spin_lock_irqsave(&conf->device_lock, flags);
2971     set_bit(Faulty, &rdev->flags);
2972     clear_bit(In_sync, &rdev->flags);
2973     mddev->degraded = raid5_calc_degraded(conf);
2974
2975     if (has_failed(conf)) {
2976         set_bit(MD_BROKEN, &conf->mddev->flags);
2977         conf->recovery_disabled = mddev->recovery_disabled;
2978
2979         pr_crit("md/raid:%s: Cannot continue operation (%d/%d failed).\n",
2980             mdname(mddev), mddev->degraded, conf->raid_disks);
2981     } else {
2982         pr_crit("md/raid:%s: Operation continuing on %d devices.\n",
2983             mdname(mddev), conf->raid_disks - mddev->degraded);
2984     }
2985
2986     spin_unlock_irqrestore(&conf->device_lock, flags);
2987     set_bit(MD_RECOVERY_INTR, &mddev->recovery);
2988
2989     set_bit(Blocked, &rdev->flags);
2990     set_mask_bits(&mddev->sb_flags, 0,
2991               BIT(MD_SB_CHANGE_DEVS) | BIT(MD_SB_CHANGE_PENDING));
2992     r5c_update_on_rdev_error(mddev, rdev);
2993 }
2994
2995 /*
2996  * Input: a 'big' sector number,
2997  * Output: index of the data and parity disk, and the sector # in them.
2998  */
2999 sector_t raid5_compute_sector(struct r5conf *conf, sector_t r_sector,
3000                   int previous, int *dd_idx,
3001                   struct stripe_head *sh)
3002 {
3003     sector_t stripe, stripe2;
3004     sector_t chunk_number;
3005     unsigned int chunk_offset;
3006     int pd_idx, qd_idx;
3007     int ddf_layout = 0;
3008     sector_t new_sector;
3009     int algorithm = previous ? conf->prev_algo
3010                  : conf->algorithm;
3011     int sectors_per_chunk = previous ? conf->prev_chunk_sectors
3012                      : conf->chunk_sectors;
3013     int raid_disks = previous ? conf->previous_raid_disks
3014                   : conf->raid_disks;
3015     int data_disks = raid_disks - conf->max_degraded;
3016
3017     /* First compute the information on this sector */
3018
3019     /*
3020      * Compute the chunk number and the sector offset inside the chunk
3021      */
3022     chunk_offset = sector_div(r_sector, sectors_per_chunk);
3023     chunk_number = r_sector;
3024
3025     /*
3026      * Compute the stripe number
3027      */
3028     stripe = chunk_number;
3029     *dd_idx = sector_div(stripe, data_disks);
3030     stripe2 = stripe;
3031     /*
3032      * Select the parity disk based on the user selected algorithm.
3033      */
3034     pd_idx = qd_idx = -1;
3035     switch(conf->level) {
3036     case 4:
3037         pd_idx = data_disks;
3038         break;
3039     case 5:
3040         switch (algorithm) {
3041         case ALGORITHM_LEFT_ASYMMETRIC:
3042             pd_idx = data_disks - sector_div(stripe2, raid_disks);
3043             if (*dd_idx >= pd_idx)
3044                 (*dd_idx)++;
3045             break;
3046         case ALGORITHM_RIGHT_ASYMMETRIC:
3047             pd_idx = sector_div(stripe2, raid_disks);
3048             if (*dd_idx >= pd_idx)
3049                 (*dd_idx)++;
3050             break;
3051         case ALGORITHM_LEFT_SYMMETRIC:
3052             pd_idx = data_disks - sector_div(stripe2, raid_disks);
3053             *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
3054             break;
3055         case ALGORITHM_RIGHT_SYMMETRIC:
3056             pd_idx = sector_div(stripe2, raid_disks);
3057             *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
3058             break;
3059         case ALGORITHM_PARITY_0:
3060             pd_idx = 0;
3061             (*dd_idx)++;
3062             break;
3063         case ALGORITHM_PARITY_N:
3064             pd_idx = data_disks;
3065             break;
3066         default:
3067             BUG();
3068         }
3069         break;
3070     case 6:
3071
3072         switch (algorithm) {
3073         case ALGORITHM_LEFT_ASYMMETRIC:
3074             pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
3075             qd_idx = pd_idx + 1;
3076             if (pd_idx == raid_disks-1) {
3077                 (*dd_idx)++;    /* Q D D D P */
3078                 qd_idx = 0;
3079             } else if (*dd_idx >= pd_idx)
3080                 (*dd_idx) += 2; /* D D P Q D */
3081             break;
3082         case ALGORITHM_RIGHT_ASYMMETRIC:
3083             pd_idx = sector_div(stripe2, raid_disks);
3084             qd_idx = pd_idx + 1;
3085             if (pd_idx == raid_disks-1) {
3086                 (*dd_idx)++;    /* Q D D D P */
3087                 qd_idx = 0;
3088             } else if (*dd_idx >= pd_idx)
3089                 (*dd_idx) += 2; /* D D P Q D */
3090             break;
3091         case ALGORITHM_LEFT_SYMMETRIC:
3092             pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
3093             qd_idx = (pd_idx + 1) % raid_disks;
3094             *dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks;
3095             break;
3096         case ALGORITHM_RIGHT_SYMMETRIC:
3097             pd_idx = sector_div(stripe2, raid_disks);
3098             qd_idx = (pd_idx + 1) % raid_disks;
3099             *dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks;
3100             break;
3101
3102         case ALGORITHM_PARITY_0:
3103             pd_idx = 0;
3104             qd_idx = 1;
3105             (*dd_idx) += 2;
3106             break;
3107         case ALGORITHM_PARITY_N:
3108             pd_idx = data_disks;
3109             qd_idx = data_disks + 1;
3110             break;
3111
3112         case ALGORITHM_ROTATING_ZERO_RESTART:
3113             /* Exactly the same as RIGHT_ASYMMETRIC, but or
3114              * of blocks for computing Q is different.
3115              */
3116             pd_idx = sector_div(stripe2, raid_disks);
3117             qd_idx = pd_idx + 1;
3118             if (pd_idx == raid_disks-1) {
3119                 (*dd_idx)++;    /* Q D D D P */
3120                 qd_idx = 0;
3121             } else if (*dd_idx >= pd_idx)
3122                 (*dd_idx) += 2; /* D D P Q D */
3123             ddf_layout = 1;
3124             break;
3125
3126         case ALGORITHM_ROTATING_N_RESTART:
3127             /* Same a left_asymmetric, by first stripe is
3128              * D D D P Q  rather than
3129              * Q D D D P
3130              */
3131             stripe2 += 1;
3132             pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
3133             qd_idx = pd_idx + 1;
3134             if (pd_idx == raid_disks-1) {
3135                 (*dd_idx)++;    /* Q D D D P */
3136                 qd_idx = 0;
3137             } else if (*dd_idx >= pd_idx)
3138                 (*dd_idx) += 2; /* D D P Q D */
3139             ddf_layout = 1;
3140             break;
3141
3142         case ALGORITHM_ROTATING_N_CONTINUE:
3143             /* Same as left_symmetric but Q is before P */
3144             pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
3145             qd_idx = (pd_idx + raid_disks - 1) % raid_disks;
3146             *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
3147             ddf_layout = 1;
3148             break;
3149
3150         case ALGORITHM_LEFT_ASYMMETRIC_6:
3151             /* RAID5 left_asymmetric, with Q on last device */
3152             pd_idx = data_disks - sector_div(stripe2, raid_disks-1);
3153             if (*dd_idx >= pd_idx)
3154                 (*dd_idx)++;
3155             qd_idx = raid_disks - 1;
3156             break;
3157
3158         case ALGORITHM_RIGHT_ASYMMETRIC_6:
3159             pd_idx = sector_div(stripe2, raid_disks-1);
3160             if (*dd_idx >= pd_idx)
3161                 (*dd_idx)++;
3162             qd_idx = raid_disks - 1;
3163             break;
3164
3165         case ALGORITHM_LEFT_SYMMETRIC_6:
3166             pd_idx = data_disks - sector_div(stripe2, raid_disks-1);
3167             *dd_idx = (pd_idx + 1 + *dd_idx) % (raid_disks-1);
3168             qd_idx = raid_disks - 1;
3169             break;
3170
3171         case ALGORITHM_RIGHT_SYMMETRIC_6:
3172             pd_idx = sector_div(stripe2, raid_disks-1);
3173             *dd_idx = (pd_idx + 1 + *dd_idx) % (raid_disks-1);
3174             qd_idx = raid_disks - 1;
3175             break;
3176
3177         case ALGORITHM_PARITY_0_6:
3178             pd_idx = 0;
3179             (*dd_idx)++;
3180             qd_idx = raid_disks - 1;
3181             break;
3182
3183         default:
3184             BUG();
3185         }
3186         break;
3187     }
3188
3189     if (sh) {
3190         sh->pd_idx = pd_idx;
3191         sh->qd_idx = qd_idx;
3192         sh->ddf_layout = ddf_layout;
3193     }
3194     /*
3195      * Finally, compute the new sector number
3196      */
3197     new_sector = (sector_t)stripe * sectors_per_chunk + chunk_offset;
3198     return new_sector;
3199 }
3200
3201 sector_t raid5_compute_blocknr(struct stripe_head *sh, int i, int previous)
3202 {
3203     struct r5conf *conf = sh->raid_conf;
3204     int raid_disks = sh->disks;
3205     int data_disks = raid_disks - conf->max_degraded;
3206     sector_t new_sector = sh->sector, check;
3207     int sectors_per_chunk = previous ? conf->prev_chunk_sectors
3208                      : conf->chunk_sectors;
3209     int algorithm = previous ? conf->prev_algo
3210                  : conf->algorithm;
3211     sector_t stripe;
3212     int chunk_offset;
3213     sector_t chunk_number;
3214     int dummy1, dd_idx = i;
3215     sector_t r_sector;
3216     struct stripe_head sh2;
3217
3218     chunk_offset = sector_div(new_sector, sectors_per_chunk);
3219     stripe = new_sector;
3220
3221     if (i == sh->pd_idx)
3222         return 0;
3223     switch(conf->level) {
3224     case 4: break;
3225     case 5:
3226         switch (algorithm) {
3227         case ALGORITHM_LEFT_ASYMMETRIC:
3228         case ALGORITHM_RIGHT_ASYMMETRIC:
3229             if (i > sh->pd_idx)
3230                 i--;
3231             break;
3232         case ALGORITHM_LEFT_SYMMETRIC:
3233         case ALGORITHM_RIGHT_SYMMETRIC:
3234             if (i < sh->pd_idx)
3235                 i += raid_disks;
3236             i -= (sh->pd_idx + 1);
3237             break;
3238         case ALGORITHM_PARITY_0:
3239             i -= 1;
3240             break;
3241         case ALGORITHM_PARITY_N:
3242             break;
3243         default:
3244             BUG();
3245         }
3246         break;
3247     case 6:
3248         if (i == sh->qd_idx)
3249             return 0; /* It is the Q disk */
3250         switch (algorithm) {
3251         case ALGORITHM_LEFT_ASYMMETRIC:
3252         case ALGORITHM_RIGHT_ASYMMETRIC:
3253         case ALGORITHM_ROTATING_ZERO_RESTART:
3254         case ALGORITHM_ROTATING_N_RESTART:
3255             if (sh->pd_idx == raid_disks-1)
3256                 i--;    /* Q D D D P */
3257             else if (i > sh->pd_idx)
3258                 i -= 2; /* D D P Q D */
3259             break;
3260         case ALGORITHM_LEFT_SYMMETRIC:
3261         case ALGORITHM_RIGHT_SYMMETRIC:
3262             if (sh->pd_idx == raid_disks-1)
3263                 i--; /* Q D D D P */
3264             else {
3265                 /* D D P Q D */
3266                 if (i < sh->pd_idx)
3267                     i += raid_disks;
3268                 i -= (sh->pd_idx + 2);
3269             }
3270             break;
3271         case ALGORITHM_PARITY_0:
3272             i -= 2;
3273             break;
3274         case ALGORITHM_PARITY_N:
3275             break;
3276         case ALGORITHM_ROTATING_N_CONTINUE:
3277             /* Like left_symmetric, but P is before Q */
3278             if (sh->pd_idx == 0)
3279                 i--;    /* P D D D Q */
3280             else {
3281                 /* D D Q P D */
3282                 if (i < sh->pd_idx)
3283                     i += raid_disks;
3284                 i -= (sh->pd_idx + 1);
3285             }
3286             break;
3287         case ALGORITHM_LEFT_ASYMMETRIC_6:
3288         case ALGORITHM_RIGHT_ASYMMETRIC_6:
3289             if (i > sh->pd_idx)
3290                 i--;
3291             break;
3292         case ALGORITHM_LEFT_SYMMETRIC_6:
3293         case ALGORITHM_RIGHT_SYMMETRIC_6:
3294             if (i < sh->pd_idx)
3295                 i += data_disks + 1;
3296             i -= (sh->pd_idx + 1);
3297             break;
3298         case ALGORITHM_PARITY_0_6:
3299             i -= 1;
3300             break;
3301         default:
3302             BUG();
3303         }
3304         break;
3305     }
3306
3307     chunk_number = stripe * data_disks + i;
3308     r_sector = chunk_number * sectors_per_chunk + chunk_offset;
3309
3310     check = raid5_compute_sector(conf, r_sector,
3311                      previous, &dummy1, &sh2);
3312     if (check != sh->sector || dummy1 != dd_idx || sh2.pd_idx != sh->pd_idx
3313         || sh2.qd_idx != sh->qd_idx) {
3314         pr_warn("md/raid:%s: compute_blocknr: map not correct\n",
3315             mdname(conf->mddev));
3316         return 0;
3317     }
3318     return r_sector;
3319 }
3320
3321 /*
3322  * There are cases where we want handle_stripe_dirtying() and
3323  * schedule_reconstruction() to delay towrite to some dev of a stripe.
3324  *
3325  * This function checks whether we want to delay the towrite. Specifically,
3326  * we delay the towrite when:
3327  *
3328  *   1. degraded stripe has a non-overwrite to the missing dev, AND this
3329  *      stripe has data in journal (for other devices).
3330  *
3331  *      In this case, when reading data for the non-overwrite dev, it is
3332  *      necessary to handle complex rmw of write back cache (prexor with
3333  *      orig_page, and xor with page). To keep read path simple, we would
3334  *      like to flush data in journal to RAID disks first, so complex rmw
3335  *      is handled in the write patch (handle_stripe_dirtying).
3336  *
3337  *   2. when journal space is critical (R5C_LOG_CRITICAL=1)
3338  *
3339  *      It is important to be able to flush all stripes in raid5-cache.
3340  *      Therefore, we need reserve some space on the journal device for
3341  *      these flushes. If flush operation includes pending writes to the
3342  *      stripe, we need to reserve (conf->raid_disk + 1) pages per stripe
3343  *      for the flush out. If we exclude these pending writes from flush
3344  *      operation, we only need (conf->max_degraded + 1) pages per stripe.
3345  *      Therefore, excluding pending writes in these cases enables more
3346  *      efficient use of the journal device.
3347  *
3348  *      Note: To make sure the stripe makes progress, we only delay
3349  *      towrite for stripes with data already in journal (injournal > 0).
3350  *      When LOG_CRITICAL, stripes with injournal == 0 will be sent to
3351  *      no_space_stripes list.
3352  *
3353  *   3. during journal failure
3354  *      In journal failure, we try to flush all cached data to raid disks
3355  *      based on data in stripe cache. The array is read-only to upper
3356  *      layers, so we would skip all pending writes.
3357  *
3358  */
3359 static inline bool delay_towrite(struct r5conf *conf,
3360                  struct r5dev *dev,
3361                  struct stripe_head_state *s)
3362 {
3363     /* case 1 above */
3364     if (!test_bit(R5_OVERWRITE, &dev->flags) &&
3365         !test_bit(R5_Insync, &dev->flags) && s->injournal)
3366         return true;
3367     /* case 2 above */
3368     if (test_bit(R5C_LOG_CRITICAL, &conf->cache_state) &&
3369         s->injournal > 0)
3370         return true;
3371     /* case 3 above */
3372     if (s->log_failed && s->injournal)
3373         return true;
3374     return false;
3375 }
3376
3377 static void
3378 schedule_reconstruction(struct stripe_head *sh, struct stripe_head_state *s,
3379              int rcw, int expand)
3380 {
3381     int i, pd_idx = sh->pd_idx, qd_idx = sh->qd_idx, disks = sh->disks;
3382     struct r5conf *conf = sh->raid_conf;
3383     int level = conf->level;
3384
3385     if (rcw) {
3386         /*
3387          * In some cases, handle_stripe_dirtying initially decided to
3388          * run rmw and allocates extra page for prexor. However, rcw is
3389          * cheaper later on. We need to free the extra page now,
3390          * because we won't be able to do that in ops_complete_prexor().
3391          */
3392         r5c_release_extra_page(sh);
3393
3394         for (i = disks; i--; ) {
3395             struct r5dev *dev = &sh->dev[i];
3396
3397             if (dev->towrite && !delay_towrite(conf, dev, s)) {
3398                 set_bit(R5_LOCKED, &dev->flags);
3399                 set_bit(R5_Wantdrain, &dev->flags);
3400                 if (!expand)
3401                     clear_bit(R5_UPTODATE, &dev->flags);
3402                 s->locked++;
3403             } else if (test_bit(R5_InJournal, &dev->flags)) {
3404                 set_bit(R5_LOCKED, &dev->flags);
3405                 s->locked++;
3406             }
3407         }
3408         /* if we are not expanding this is a proper write request, and
3409          * there will be bios with new data to be drained into the
3410          * stripe cache
3411          */
3412         if (!expand) {
3413             if (!s->locked)
3414                 /* False alarm, nothing to do */
3415                 return;
3416             sh->reconstruct_state = reconstruct_state_drain_run;
3417             set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
3418         } else
3419             sh->reconstruct_state = reconstruct_state_run;
3420
3421         set_bit(STRIPE_OP_RECONSTRUCT, &s->ops_request);
3422
3423         if (s->locked + conf->max_degraded == disks)
3424             if (!test_and_set_bit(STRIPE_FULL_WRITE, &sh->state))
3425                 atomic_inc(&conf->pending_full_writes);
3426     } else {
3427         BUG_ON(!(test_bit(R5_UPTODATE, &sh->dev[pd_idx].flags) ||
3428             test_bit(R5_Wantcompute, &sh->dev[pd_idx].flags)));
3429         BUG_ON(level == 6 &&
3430             (!(test_bit(R5_UPTODATE, &sh->dev[qd_idx].flags) ||
3431                test_bit(R5_Wantcompute, &sh->dev[qd_idx].flags))));
3432
3433         for (i = disks; i--; ) {
3434             struct r5dev *dev = &sh->dev[i];
3435             if (i == pd_idx || i == qd_idx)
3436                 continue;
3437
3438             if (dev->towrite &&
3439                 (test_bit(R5_UPTODATE, &dev->flags) ||
3440                  test_bit(R5_Wantcompute, &dev->flags))) {
3441                 set_bit(R5_Wantdrain, &dev->flags);
3442                 set_bit(R5_LOCKED, &dev->flags);
3443                 clear_bit(R5_UPTODATE, &dev->flags);
3444                 s->locked++;
3445             } else if (test_bit(R5_InJournal, &dev->flags)) {
3446                 set_bit(R5_LOCKED, &dev->flags);
3447                 s->locked++;
3448             }
3449         }
3450         if (!s->locked)
3451             /* False alarm - nothing to do */
3452             return;
3453         sh->reconstruct_state = reconstruct_state_prexor_drain_run;
3454         set_bit(STRIPE_OP_PREXOR, &s->ops_request);
3455         set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
3456         set_bit(STRIPE_OP_RECONSTRUCT, &s->ops_request);
3457     }
3458
3459     /* keep the parity disk(s) locked while asynchronous operations
3460      * are in flight
3461      */
3462     set_bit(R5_LOCKED, &sh->dev[pd_idx].flags);
3463     clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
3464     s->locked++;
3465
3466     if (level == 6) {
3467         int qd_idx = sh->qd_idx;
3468         struct r5dev *dev = &sh->dev[qd_idx];
3469
3470         set_bit(R5_LOCKED, &dev->flags);
3471         clear_bit(R5_UPTODATE, &dev->flags);
3472         s->locked++;
3473     }
3474
3475     if (raid5_has_ppl(sh->raid_conf) && sh->ppl_page &&
3476         test_bit(STRIPE_OP_BIODRAIN, &s->ops_request) &&
3477         !test_bit(STRIPE_FULL_WRITE, &sh->state) &&
3478         test_bit(R5_Insync, &sh->dev[pd_idx].flags))
3479         set_bit(STRIPE_OP_PARTIAL_PARITY, &s->ops_request);
3480
3481     pr_debug("%s: stripe %llu locked: %d ops_request: %lx\n",
3482         __func__, (unsigned long long)sh->sector,
3483         s->locked, s->ops_request);
3484 }
3485
3486 static bool stripe_bio_overlaps(struct stripe_head *sh, struct bio *bi,
3487                 int dd_idx, int forwrite)
3488 {
3489     struct r5conf *conf = sh->raid_conf;
3490     struct bio **bip;
3491
3492     pr_debug("checking bi b#%llu to stripe s#%llu\n",
3493          bi->bi_iter.bi_sector, sh->sector);
3494
3495     /* Don't allow new IO added to stripes in batch list */
3496     if (sh->batch_head)
3497         return true;
3498
3499     if (forwrite)
3500         bip = &sh->dev[dd_idx].towrite;
3501     else
3502         bip = &sh->dev[dd_idx].toread;
3503
3504     while (*bip && (*bip)->bi_iter.bi_sector < bi->bi_iter.bi_sector) {
3505         if (bio_end_sector(*bip) > bi->bi_iter.bi_sector)
3506             return true;
3507         bip = &(*bip)->bi_next;
3508     }
3509
3510     if (*bip && (*bip)->bi_iter.bi_sector < bio_end_sector(bi))
3511         return true;
3512
3513     if (forwrite && raid5_has_ppl(conf)) {
3514         /*
3515          * With PPL only writes to consecutive data chunks within a
3516          * stripe are allowed because for a single stripe_head we can
3517          * only have one PPL entry at a time, which describes one data
3518          * range. Not really an overlap, but wait_for_overlap can be
3519          * used to handle this.
3520          */
3521         sector_t sector;
3522         sector_t first = 0;
3523         sector_t last = 0;
3524         int count = 0;
3525         int i;
3526
3527         for (i = 0; i < sh->disks; i++) {
3528             if (i != sh->pd_idx &&
3529                 (i == dd_idx || sh->dev[i].towrite)) {
3530                 sector = sh->dev[i].sector;
3531                 if (count == 0 || sector < first)
3532                     first = sector;
3533                 if (sector > last)
3534                     last = sector;
3535                 count++;
3536             }
3537         }
3538
3539         if (first + conf->chunk_sectors * (count - 1) != last)
3540             return true;
3541     }
3542
3543     return false;
3544 }
3545
3546 static void __add_stripe_bio(struct stripe_head *sh, struct bio *bi,
3547                  int dd_idx, int forwrite, int previous)
3548 {
3549     struct r5conf *conf = sh->raid_conf;
3550     struct bio **bip;
3551     int firstwrite = 0;
3552
3553     if (forwrite) {
3554         bip = &sh->dev[dd_idx].towrite;
3555         if (!*bip)
3556             firstwrite = 1;
3557     } else {
3558         bip = &sh->dev[dd_idx].toread;
3559     }
3560
3561     while (*bip && (*bip)->bi_iter.bi_sector < bi->bi_iter.bi_sector)
3562         bip = &(*bip)->bi_next;
3563
3564     if (!forwrite || previous)
3565         clear_bit(STRIPE_BATCH_READY, &sh->state);
3566
3567     BUG_ON(*bip && bi->bi_next && (*bip) != bi->bi_next);
3568     if (*bip)
3569         bi->bi_next = *bip;
3570     *bip = bi;
3571     bio_inc_remaining(bi);
3572     md_write_inc(conf->mddev, bi);
3573
3574     if (forwrite) {
3575         /* check if page is covered */
3576         sector_t sector = sh->dev[dd_idx].sector;
3577         for (bi=sh->dev[dd_idx].towrite;
3578              sector < sh->dev[dd_idx].sector + RAID5_STRIPE_SECTORS(conf) &&
3579                  bi && bi->bi_iter.bi_sector <= sector;
3580              bi = r5_next_bio(conf, bi, sh->dev[dd_idx].sector)) {
3581             if (bio_end_sector(bi) >= sector)
3582                 sector = bio_end_sector(bi);
3583         }
3584         if (sector >= sh->dev[dd_idx].sector + RAID5_STRIPE_SECTORS(conf))
3585             if (!test_and_set_bit(R5_OVERWRITE, &sh->dev[dd_idx].flags))
3586                 sh->overwrite_disks++;
3587     }
3588
3589     pr_debug("added bi b#%llu to stripe s#%llu, disk %d, logical %llu\n",
3590          (*bip)->bi_iter.bi_sector, sh->sector, dd_idx,
3591          sh->dev[dd_idx].sector);
3592
3593     if (conf->mddev->bitmap && firstwrite) {
3594         /* Cannot hold spinlock over bitmap_startwrite,
3595          * but must ensure this isn't added to a batch until
3596          * we have added to the bitmap and set bm_seq.
3597          * So set STRIPE_BITMAP_PENDING to prevent
3598          * batching.
3599          * If multiple __add_stripe_bio() calls race here they
3600          * much all set STRIPE_BITMAP_PENDING.  So only the first one
3601          * to complete "bitmap_startwrite" gets to set
3602          * STRIPE_BIT_DELAY.  This is important as once a stripe
3603          * is added to a batch, STRIPE_BIT_DELAY cannot be changed
3604          * any more.
3605          */
3606         set_bit(STRIPE_BITMAP_PENDING, &sh->state);
3607         spin_unlock_irq(&sh->stripe_lock);
3608         md_bitmap_startwrite(conf->mddev->bitmap, sh->sector,
3609                      RAID5_STRIPE_SECTORS(conf), 0);
3610         spin_lock_irq(&sh->stripe_lock);
3611         clear_bit(STRIPE_BITMAP_PENDING, &sh->state);
3612         if (!sh->batch_head) {
3613             sh->bm_seq = conf->seq_flush+1;
3614             set_bit(STRIPE_BIT_DELAY, &sh->state);
3615         }
3616     }
3617 }
3618
3619 /*
3620  * Each stripe/dev can have one or more bios attached.
3621  * toread/towrite point to the first in a chain.
3622  * The bi_next chain must be in order.
3623  */
3624 static bool add_stripe_bio(struct stripe_head *sh, struct bio *bi,
3625                int dd_idx, int forwrite, int previous)
3626 {
3627     spin_lock_irq(&sh->stripe_lock);
3628
3629     if (stripe_bio_overlaps(sh, bi, dd_idx, forwrite)) {
3630         set_bit(R5_Overlap, &sh->dev[dd_idx].flags);
3631         spin_unlock_irq(&sh->stripe_lock);
3632         return false;
3633     }
3634
3635     __add_stripe_bio(sh, bi, dd_idx, forwrite, previous);
3636     spin_unlock_irq(&sh->stripe_lock);
3637     return true;
3638 }
3639
3640 static void end_reshape(struct r5conf *conf);
3641
3642 static void stripe_set_idx(sector_t stripe, struct r5conf *conf, int previous,
3643                 struct stripe_head *sh)
3644 {
3645     int sectors_per_chunk =
3646         previous ? conf->prev_chunk_sectors : conf->chunk_sectors;
3647     int dd_idx;
3648     int chunk_offset = sector_div(stripe, sectors_per_chunk);
3649     int disks = previous ? conf->previous_raid_disks : conf->raid_disks;
3650
3651     raid5_compute_sector(conf,
3652                  stripe * (disks - conf->max_degraded)
3653                  *sectors_per_chunk + chunk_offset,
3654                  previous,
3655                  &dd_idx, sh);
3656 }
3657
3658 static void
3659 handle_failed_stripe(struct r5conf *conf, struct stripe_head *sh,
3660              struct stripe_head_state *s, int disks)
3661 {
3662     int i;
3663     BUG_ON(sh->batch_head);
3664     for (i = disks; i--; ) {
3665         struct bio *bi;
3666         int bitmap_end = 0;
3667
3668         if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
3669             struct md_rdev *rdev;
3670             rcu_read_lock();
3671             rdev = rcu_dereference(conf->disks[i].rdev);
3672             if (rdev && test_bit(In_sync, &rdev->flags) &&
3673                 !test_bit(Faulty, &rdev->flags))
3674                 atomic_inc(&rdev->nr_pending);
3675             else
3676                 rdev = NULL;
3677             rcu_read_unlock();
3678             if (rdev) {
3679                 if (!rdev_set_badblocks(
3680                         rdev,
3681                         sh->sector,
3682                         RAID5_STRIPE_SECTORS(conf), 0))
3683                     md_error(conf->mddev, rdev);
3684                 rdev_dec_pending(rdev, conf->mddev);
3685             }
3686         }
3687         spin_lock_irq(&sh->stripe_lock);
3688         /* fail all writes first */
3689         bi = sh->dev[i].towrite;
3690         sh->dev[i].towrite = NULL;
3691         sh->overwrite_disks = 0;
3692         spin_unlock_irq(&sh->stripe_lock);
3693         if (bi)
3694             bitmap_end = 1;
3695
3696         log_stripe_write_finished(sh);
3697
3698         if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
3699             wake_up(&conf->wait_for_overlap);
3700
3701         while (bi && bi->bi_iter.bi_sector <
3702             sh->dev[i].sector + RAID5_STRIPE_SECTORS(conf)) {
3703             struct bio *nextbi = r5_next_bio(conf, bi, sh->dev[i].sector);
3704
3705             md_write_end(conf->mddev);
3706             bio_io_error(bi);
3707             bi = nextbi;
3708         }
3709         if (bitmap_end)
3710             md_bitmap_endwrite(conf->mddev->bitmap, sh->sector,
3711                        RAID5_STRIPE_SECTORS(conf), 0, 0);
3712         bitmap_end = 0;
3713         /* and fail all 'written' */
3714         bi = sh->dev[i].written;
3715         sh->dev[i].written = NULL;
3716         if (test_and_clear_bit(R5_SkipCopy, &sh->dev[i].flags)) {
3717             WARN_ON(test_bit(R5_UPTODATE, &sh->dev[i].flags));
3718             sh->dev[i].page = sh->dev[i].orig_page;
3719         }
3720
3721         if (bi) bitmap_end = 1;
3722         while (bi && bi->bi_iter.bi_sector <
3723                sh->dev[i].sector + RAID5_STRIPE_SECTORS(conf)) {
3724             struct bio *bi2 = r5_next_bio(conf, bi, sh->dev[i].sector);
3725
3726             md_write_end(conf->mddev);
3727             bio_io_error(bi);
3728             bi = bi2;
3729         }
3730
3731         /* fail any reads if this device is non-operational and
3732          * the data has not reached the cache yet.
3733          */
3734         if (!test_bit(R5_Wantfill, &sh->dev[i].flags) &&
3735             s->failed > conf->max_degraded &&
3736             (!test_bit(R5_Insync, &sh->dev[i].flags) ||
3737               test_bit(R5_ReadError, &sh->dev[i].flags))) {
3738             spin_lock_irq(&sh->stripe_lock);
3739             bi = sh->dev[i].toread;
3740             sh->dev[i].toread = NULL;
3741             spin_unlock_irq(&sh->stripe_lock);
3742             if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
3743                 wake_up(&conf->wait_for_overlap);
3744             if (bi)
3745                 s->to_read--;
3746             while (bi && bi->bi_iter.bi_sector <
3747                    sh->dev[i].sector + RAID5_STRIPE_SECTORS(conf)) {
3748                 struct bio *nextbi =
3749                     r5_next_bio(conf, bi, sh->dev[i].sector);
3750
3751                 bio_io_error(bi);
3752                 bi = nextbi;
3753             }
3754         }
3755         if (bitmap_end)
3756             md_bitmap_endwrite(conf->mddev->bitmap, sh->sector,
3757                        RAID5_STRIPE_SECTORS(conf), 0, 0);
3758         /* If we were in the middle of a write the parity block might
3759          * still be locked - so just clear all R5_LOCKED flags
3760          */
3761         clear_bit(R5_LOCKED, &sh->dev[i].flags);
3762     }
3763     s->to_write = 0;
3764     s->written = 0;
3765
3766     if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state))
3767         if (atomic_dec_and_test(&conf->pending_full_writes))
3768             md_wakeup_thread(conf->mddev->thread);
3769 }
3770
3771 static void
3772 handle_failed_sync(struct r5conf *conf, struct stripe_head *sh,
3773            struct stripe_head_state *s)
3774 {
3775     int abort = 0;
3776     int i;
3777
3778     BUG_ON(sh->batch_head);
3779     clear_bit(STRIPE_SYNCING, &sh->state);
3780     if (test_and_clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags))
3781         wake_up(&conf->wait_for_overlap);
3782     s->syncing = 0;
3783     s->replacing = 0;
3784     /* There is nothing more to do for sync/check/repair.
3785      * Don't even need to abort as that is handled elsewhere
3786      * if needed, and not always wanted e.g. if there is a known
3787      * bad block here.
3788      * For recover/replace we need to record a bad block on all
3789      * non-sync devices, or abort the recovery
3790      */
3791     if (test_bit(MD_RECOVERY_RECOVER, &conf->mddev->recovery)) {
3792         /* During recovery devices cannot be removed, so
3793          * locking and refcounting of rdevs is not needed
3794          */
3795         rcu_read_lock();
3796         for (i = 0; i < conf->raid_disks; i++) {
3797             struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
3798             if (rdev
3799                 && !test_bit(Faulty, &rdev->flags)
3800                 && !test_bit(In_sync, &rdev->flags)
3801                 && !rdev_set_badblocks(rdev, sh->sector,
3802                            RAID5_STRIPE_SECTORS(conf), 0))
3803                 abort = 1;
3804             rdev = rcu_dereference(conf->disks[i].replacement);
3805             if (rdev
3806                 && !test_bit(Faulty, &rdev->flags)
3807                 && !test_bit(In_sync, &rdev->flags)
3808                 && !rdev_set_badblocks(rdev, sh->sector,
3809                            RAID5_STRIPE_SECTORS(conf), 0))
3810                 abort = 1;
3811         }
3812         rcu_read_unlock();
3813         if (abort)
3814             conf->recovery_disabled =
3815                 conf->mddev->recovery_disabled;
3816     }
3817     md_done_sync(conf->mddev, RAID5_STRIPE_SECTORS(conf), !abort);
3818 }
3819
3820 static int want_replace(struct stripe_head *sh, int disk_idx)
3821 {
3822     struct md_rdev *rdev;
3823     int rv = 0;
3824
3825     rcu_read_lock();
3826     rdev = rcu_dereference(sh->raid_conf->disks[disk_idx].replacement);
3827     if (rdev
3828         && !test_bit(Faulty, &rdev->flags)
3829         && !test_bit(In_sync, &rdev->flags)
3830         && (rdev->recovery_offset <= sh->sector
3831         || rdev->mddev->recovery_cp <= sh->sector))
3832         rv = 1;
3833     rcu_read_unlock();
3834     return rv;
3835 }
3836
3837 static int need_this_block(struct stripe_head *sh, struct stripe_head_state *s,
3838                int disk_idx, int disks)
3839 {
3840     struct r5dev *dev = &sh->dev[disk_idx];
3841     struct r5dev *fdev[2] = { &sh->dev[s->failed_num[0]],
3842                   &sh->dev[s->failed_num[1]] };
3843     int i;
3844     bool force_rcw = (sh->raid_conf->rmw_level == PARITY_DISABLE_RMW);
3845
3846
3847     if (test_bit(R5_LOCKED, &dev->flags) ||
3848         test_bit(R5_UPTODATE, &dev->flags))
3849         /* No point reading this as we already have it or have
3850          * decided to get it.
3851          */
3852         return 0;
3853
3854     if (dev->toread ||
3855         (dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags)))
3856         /* We need this block to directly satisfy a request */
3857         return 1;
3858
3859     if (s->syncing || s->expanding ||
3860         (s->replacing && want_replace(sh, disk_idx)))
3861         /* When syncing, or expanding we read everything.
3862          * When replacing, we need the replaced block.
3863          */
3864         return 1;
3865
3866     if ((s->failed >= 1 && fdev[0]->toread) ||
3867         (s->failed >= 2 && fdev[1]->toread))
3868         /* If we want to read from a failed device, then
3869          * we need to actually read every other device.
3870          */
3871         return 1;
3872
3873     /* Sometimes neither read-modify-write nor reconstruct-write
3874      * cycles can work.  In those cases we read every block we
3875      * can.  Then the parity-update is certain to have enough to
3876      * work with.
3877      * This can only be a problem when we need to write something,
3878      * and some device has failed.  If either of those tests
3879      * fail we need look no further.
3880      */
3881     if (!s->failed || !s->to_write)
3882         return 0;
3883
3884     if (test_bit(R5_Insync, &dev->flags) &&
3885         !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
3886         /* Pre-reads at not permitted until after short delay
3887          * to gather multiple requests.  However if this
3888          * device is no Insync, the block could only be computed
3889          * and there is no need to delay that.
3890          */
3891         return 0;
3892
3893     for (i = 0; i < s->failed && i < 2; i++) {
3894         if (fdev[i]->towrite &&
3895             !test_bit(R5_UPTODATE, &fdev[i]->flags) &&
3896             !test_bit(R5_OVERWRITE, &fdev[i]->flags))
3897             /* If we have a partial write to a failed
3898              * device, then we will need to reconstruct
3899              * the content of that device, so all other
3900              * devices must be read.
3901              */
3902             return 1;
3903
3904         if (s->failed >= 2 &&
3905             (fdev[i]->towrite ||
3906              s->failed_num[i] == sh->pd_idx ||
3907              s->failed_num[i] == sh->qd_idx) &&
3908             !test_bit(R5_UPTODATE, &fdev[i]->flags))
3909             /* In max degraded raid6, If the failed disk is P, Q,
3910              * or we want to read the failed disk, we need to do
3911              * reconstruct-write.
3912              */
3913             force_rcw = true;
3914     }
3915
3916     /* If we are forced to do a reconstruct-write, because parity
3917      * cannot be trusted and we are currently recovering it, there
3918      * is extra need to be careful.
3919      * If one of the devices that we would need to read, because
3920      * it is not being overwritten (and maybe not written at all)
3921      * is missing/faulty, then we need to read everything we can.
3922      */
3923     if (!force_rcw &&
3924         sh->sector < sh->raid_conf->mddev->recovery_cp)
3925         /* reconstruct-write isn't being forced */
3926         return 0;
3927     for (i = 0; i < s->failed && i < 2; i++) {
3928         if (s->failed_num[i] != sh->pd_idx &&
3929             s->failed_num[i] != sh->qd_idx &&
3930             !test_bit(R5_UPTODATE, &fdev[i]->flags) &&
3931             !test_bit(R5_OVERWRITE, &fdev[i]->flags))
3932             return 1;
3933     }
3934
3935     return 0;
3936 }
3937
3938 /* fetch_block - checks the given member device to see if its data needs
3939  * to be read or computed to satisfy a request.
3940  *
3941  * Returns 1 when no more member devices need to be checked, otherwise returns
3942  * 0 to tell the loop in handle_stripe_fill to continue
3943  */
3944 static int fetch_block(struct stripe_head *sh, struct stripe_head_state *s,
3945                int disk_idx, int disks)
3946 {
3947     struct r5dev *dev = &sh->dev[disk_idx];
3948
3949     /* is the data in this block needed, and can we get it? */
3950     if (need_this_block(sh, s, disk_idx, disks)) {
3951         /* we would like to get this block, possibly by computing it,
3952          * otherwise read it if the backing disk is insync
3953          */
3954         BUG_ON(test_bit(R5_Wantcompute, &dev->flags));
3955         BUG_ON(test_bit(R5_Wantread, &dev->flags));
3956         BUG_ON(sh->batch_head);
3957
3958         /*
3959          * In the raid6 case if the only non-uptodate disk is P
3960          * then we already trusted P to compute the other failed
3961          * drives. It is safe to compute rather than re-read P.
3962          * In other cases we only compute blocks from failed
3963          * devices, otherwise check/repair might fail to detect
3964          * a real inconsistency.
3965          */
3966
3967         if ((s->uptodate == disks - 1) &&
3968             ((sh->qd_idx >= 0 && sh->pd_idx == disk_idx) ||
3969             (s->failed && (disk_idx == s->failed_num[0] ||
3970                    disk_idx == s->failed_num[1])))) {
3971             /* have disk failed, and we're requested to fetch it;
3972              * do compute it
3973              */
3974             pr_debug("Computing stripe %llu block %d\n",
3975                    (unsigned long long)sh->sector, disk_idx);
3976             set_bit(STRIPE_COMPUTE_RUN, &sh->state);
3977             set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
3978             set_bit(R5_Wantcompute, &dev->flags);
3979             sh->ops.target = disk_idx;
3980             sh->ops.target2 = -1; /* no 2nd target */
3981             s->req_compute = 1;
3982             /* Careful: from this point on 'uptodate' is in the eye
3983              * of raid_run_ops which services 'compute' operations
3984              * before writes. R5_Wantcompute flags a block that will
3985              * be R5_UPTODATE by the time it is needed for a
3986              * subsequent operation.
3987              */
3988             s->uptodate++;
3989             return 1;
3990         } else if (s->uptodate == disks-2 && s->failed >= 2) {
3991             /* Computing 2-failure is *very* expensive; only
3992              * do it if failed >= 2
3993              */
3994             int other;
3995             for (other = disks; other--; ) {
3996                 if (other == disk_idx)
3997                     continue;
3998                 if (!test_bit(R5_UPTODATE,
3999                       &sh->dev[other].flags))
4000                     break;
4001             }
4002             BUG_ON(other < 0);
4003             pr_debug("Computing stripe %llu blocks %d,%d\n",
4004                    (unsigned long long)sh->sector,
4005                    disk_idx, other);
4006             set_bit(STRIPE_COMPUTE_RUN, &sh->state);
4007             set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
4008             set_bit(R5_Wantcompute, &sh->dev[disk_idx].flags);
4009             set_bit(R5_Wantcompute, &sh->dev[other].flags);
4010             sh->ops.target = disk_idx;
4011             sh->ops.target2 = other;
4012             s->uptodate += 2;
4013             s->req_compute = 1;
4014             return 1;
4015         } else if (test_bit(R5_Insync, &dev->flags)) {
4016             set_bit(R5_LOCKED, &dev->flags);
4017             set_bit(R5_Wantread, &dev->flags);
4018             s->locked++;
4019             pr_debug("Reading block %d (sync=%d)\n",
4020                 disk_idx, s->syncing);
4021         }
4022     }
4023
4024     return 0;
4025 }
4026
4027 /*
4028  * handle_stripe_fill - read or compute data to satisfy pending requests.
4029  */
4030 static void handle_stripe_fill(struct stripe_head *sh,
4031                    struct stripe_head_state *s,
4032                    int disks)
4033 {
4034     int i;
4035
4036     /* look for blocks to read/compute, skip this if a compute
4037      * is already in flight, or if the stripe contents are in the
4038      * midst of changing due to a write
4039      */
4040     if (!test_bit(STRIPE_COMPUTE_RUN, &sh->state) && !sh->check_state &&
4041         !sh->reconstruct_state) {
4042
4043         /*
4044          * For degraded stripe with data in journal, do not handle
4045          * read requests yet, instead, flush the stripe to raid
4046          * disks first, this avoids handling complex rmw of write
4047          * back cache (prexor with orig_page, and then xor with
4048          * page) in the read path
4049          */
4050         if (s->injournal && s->failed) {
4051             if (test_bit(STRIPE_R5C_CACHING, &sh->state))
4052                 r5c_make_stripe_write_out(sh);
4053             goto out;
4054         }
4055
4056         for (i = disks; i--; )
4057             if (fetch_block(sh, s, i, disks))
4058                 break;
4059     }
4060 out:
4061     set_bit(STRIPE_HANDLE, &sh->state);
4062 }
4063
4064 static void break_stripe_batch_list(struct stripe_head *head_sh,
4065                     unsigned long handle_flags);
4066 /* handle_stripe_clean_event
4067  * any written block on an uptodate or failed drive can be returned.
4068  * Note that if we 'wrote' to a failed drive, it will be UPTODATE, but
4069  * never LOCKED, so we don't need to test 'failed' directly.
4070  */
4071 static void handle_stripe_clean_event(struct r5conf *conf,
4072     struct stripe_head *sh, int disks)
4073 {
4074     int i;
4075     struct r5dev *dev;
4076     int discard_pending = 0;
4077     struct stripe_head *head_sh = sh;
4078     bool do_endio = false;
4079
4080     for (i = disks; i--; )
4081         if (sh->dev[i].written) {
4082             dev = &sh->dev[i];
4083             if (!test_bit(R5_LOCKED, &dev->flags) &&
4084                 (test_bit(R5_UPTODATE, &dev->flags) ||
4085                  test_bit(R5_Discard, &dev->flags) ||
4086                  test_bit(R5_SkipCopy, &dev->flags))) {
4087                 /* We can return any write requests */
4088                 struct bio *wbi, *wbi2;
4089                 pr_debug("Return write for disc %d\n", i);
4090                 if (test_and_clear_bit(R5_Discard, &dev->flags))
4091                     clear_bit(R5_UPTODATE, &dev->flags);
4092                 if (test_and_clear_bit(R5_SkipCopy, &dev->flags)) {
4093                     WARN_ON(test_bit(R5_UPTODATE, &dev->flags));
4094                 }
4095                 do_endio = true;
4096
4097 returnbi:
4098                 dev->page = dev->orig_page;
4099                 wbi = dev->written;
4100                 dev->written = NULL;
4101                 while (wbi && wbi->bi_iter.bi_sector <
4102                     dev->sector + RAID5_STRIPE_SECTORS(conf)) {
4103                     wbi2 = r5_next_bio(conf, wbi, dev->sector);
4104                     md_write_end(conf->mddev);
4105                     bio_endio(wbi);
4106                     wbi = wbi2;
4107                 }
4108                 md_bitmap_endwrite(conf->mddev->bitmap, sh->sector,
4109                            RAID5_STRIPE_SECTORS(conf),
4110                            !test_bit(STRIPE_DEGRADED, &sh->state),
4111                            0);
4112                 if (head_sh->batch_head) {
4113                     sh = list_first_entry(&sh->batch_list,
4114                                   struct stripe_head,
4115                                   batch_list);
4116                     if (sh != head_sh) {
4117                         dev = &sh->dev[i];
4118                         goto returnbi;
4119                     }
4120                 }
4121                 sh = head_sh;
4122                 dev = &sh->dev[i];
4123             } else if (test_bit(R5_Discard, &dev->flags))
4124                 discard_pending = 1;
4125         }
4126
4127     log_stripe_write_finished(sh);
4128
4129     if (!discard_pending &&
4130         test_bit(R5_Discard, &sh->dev[sh->pd_idx].flags)) {
4131         int hash;
4132         clear_bit(R5_Discard, &sh->dev[sh->pd_idx].flags);
4133         clear_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags);
4134         if (sh->qd_idx >= 0) {
4135             clear_bit(R5_Discard, &sh->dev[sh->qd_idx].flags);
4136             clear_bit(R5_UPTODATE, &sh->dev[sh->qd_idx].flags);
4137         }
4138         /* now that discard is done we can proceed with any sync */
4139         clear_bit(STRIPE_DISCARD, &sh->state);
4140         /*
4141          * SCSI discard will change some bio fields and the stripe has
4142          * no updated data, so remove it from hash list and the stripe
4143          * will be reinitialized
4144          */
4145 unhash:
4146         hash = sh->hash_lock_index;
4147         spin_lock_irq(conf->hash_locks + hash);
4148         remove_hash(sh);
4149         spin_unlock_irq(conf->hash_locks + hash);
4150         if (head_sh->batch_head) {
4151             sh = list_first_entry(&sh->batch_list,
4152                           struct stripe_head, batch_list);
4153             if (sh != head_sh)
4154                     goto unhash;
4155         }
4156         sh = head_sh;
4157
4158         if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state))
4159             set_bit(STRIPE_HANDLE, &sh->state);
4160
4161     }
4162
4163     if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state))
4164         if (atomic_dec_and_test(&conf->pending_full_writes))
4165             md_wakeup_thread(conf->mddev->thread);
4166
4167     if (head_sh->batch_head && do_endio)
4168         break_stripe_batch_list(head_sh, STRIPE_EXPAND_SYNC_FLAGS);
4169 }
4170
4171 /*
4172  * For RMW in write back cache, we need extra page in prexor to store the
4173  * old data. This page is stored in dev->orig_page.
4174  *
4175  * This function checks whether we have data for prexor. The exact logic
4176  * is:
4177  *       R5_UPTODATE && (!R5_InJournal || R5_OrigPageUPTDODATE)
4178  */
4179 static inline bool uptodate_for_rmw(struct r5dev *dev)
4180 {
4181     return (test_bit(R5_UPTODATE, &dev->flags)) &&
4182         (!test_bit(R5_InJournal, &dev->flags) ||
4183          test_bit(R5_OrigPageUPTDODATE, &dev->flags));
4184 }
4185
4186 static int handle_stripe_dirtying(struct r5conf *conf,
4187                   struct stripe_head *sh,
4188                   struct stripe_head_state *s,
4189                   int disks)
4190 {
4191     int rmw = 0, rcw = 0, i;
4192     sector_t recovery_cp = conf->mddev->recovery_cp;
4193
4194     /* Check whether resync is now happening or should start.
4195      * If yes, then the array is dirty (after unclean shutdown or
4196      * initial creation), so parity in some stripes might be inconsistent.
4197      * In this case, we need to always do reconstruct-write, to ensure
4198      * that in case of drive failure or read-error correction, we
4199      * generate correct data from the parity.
4200      */
4201     if (conf->rmw_level == PARITY_DISABLE_RMW ||
4202         (recovery_cp < MaxSector && sh->sector >= recovery_cp &&
4203          s->failed == 0)) {
4204         /* Calculate the real rcw later - for now make it
4205          * look like rcw is cheaper
4206          */
4207         rcw = 1; rmw = 2;
4208         pr_debug("force RCW rmw_level=%u, recovery_cp=%llu sh->sector=%llu\n",
4209              conf->rmw_level, (unsigned long long)recovery_cp,
4210              (unsigned long long)sh->sector);
4211     } else for (i = disks; i--; ) {
4212         /* would I have to read this buffer for read_modify_write */
4213         struct r5dev *dev = &sh->dev[i];
4214         if (((dev->towrite && !delay_towrite(conf, dev, s)) ||
4215              i == sh->pd_idx || i == sh->qd_idx ||
4216              test_bit(R5_InJournal, &dev->flags)) &&
4217             !test_bit(R5_LOCKED, &dev->flags) &&
4218             !(uptodate_for_rmw(dev) ||
4219               test_bit(R5_Wantcompute, &dev->flags))) {
4220             if (test_bit(R5_Insync, &dev->flags))
4221                 rmw++;
4222             else
4223                 rmw += 2*disks;  /* cannot read it */
4224         }
4225         /* Would I have to read this buffer for reconstruct_write */
4226         if (!test_bit(R5_OVERWRITE, &dev->flags) &&
4227             i != sh->pd_idx && i != sh->qd_idx &&
4228             !test_bit(R5_LOCKED, &dev->flags) &&
4229             !(test_bit(R5_UPTODATE, &dev->flags) ||
4230               test_bit(R5_Wantcompute, &dev->flags))) {
4231             if (test_bit(R5_Insync, &dev->flags))
4232                 rcw++;
4233             else
4234                 rcw += 2*disks;
4235         }
4236     }
4237
4238     pr_debug("for sector %llu state 0x%lx, rmw=%d rcw=%d\n",
4239          (unsigned long long)sh->sector, sh->state, rmw, rcw);
4240     set_bit(STRIPE_HANDLE, &sh->state);
4241     if ((rmw < rcw || (rmw == rcw && conf->rmw_level == PARITY_PREFER_RMW)) && rmw > 0) {
4242         /* prefer read-modify-write, but need to get some data */
4243         if (conf->mddev->queue)
4244             blk_add_trace_msg(conf->mddev->queue,
4245                       "raid5 rmw %llu %d",
4246                       (unsigned long long)sh->sector, rmw);
4247         for (i = disks; i--; ) {
4248             struct r5dev *dev = &sh->dev[i];
4249             if (test_bit(R5_InJournal, &dev->flags) &&
4250                 dev->page == dev->orig_page &&
4251                 !test_bit(R5_LOCKED, &sh->dev[sh->pd_idx].flags)) {
4252                 /* alloc page for prexor */
4253                 struct page *p = alloc_page(GFP_NOIO);
4254
4255                 if (p) {
4256                     dev->orig_page = p;
4257                     continue;
4258                 }
4259
4260                 /*
4261                  * alloc_page() failed, try use
4262                  * disk_info->extra_page
4263                  */
4264                 if (!test_and_set_bit(R5C_EXTRA_PAGE_IN_USE,
4265                               &conf->cache_state)) {
4266                     r5c_use_extra_page(sh);
4267                     break;
4268                 }
4269
4270                 /* extra_page in use, add to delayed_list */
4271                 set_bit(STRIPE_DELAYED, &sh->state);
4272                 s->waiting_extra_page = 1;
4273                 return -EAGAIN;
4274             }
4275         }
4276
4277         for (i = disks; i--; ) {
4278             struct r5dev *dev = &sh->dev[i];
4279             if (((dev->towrite && !delay_towrite(conf, dev, s)) ||
4280                  i == sh->pd_idx || i == sh->qd_idx ||
4281                  test_bit(R5_InJournal, &dev->flags)) &&
4282                 !test_bit(R5_LOCKED, &dev->flags) &&
4283                 !(uptodate_for_rmw(dev) ||
4284                   test_bit(R5_Wantcompute, &dev->flags)) &&
4285                 test_bit(R5_Insync, &dev->flags)) {
4286                 if (test_bit(STRIPE_PREREAD_ACTIVE,
4287                          &sh->state)) {
4288                     pr_debug("Read_old block %d for r-m-w\n",
4289                          i);
4290                     set_bit(R5_LOCKED, &dev->flags);
4291                     set_bit(R5_Wantread, &dev->flags);
4292                     s->locked++;
4293                 } else
4294                     set_bit(STRIPE_DELAYED, &sh->state);
4295             }
4296         }
4297     }
4298     if ((rcw < rmw || (rcw == rmw && conf->rmw_level != PARITY_PREFER_RMW)) && rcw > 0) {
4299         /* want reconstruct write, but need to get some data */
4300         int qread =0;
4301         rcw = 0;
4302         for (i = disks; i--; ) {
4303             struct r5dev *dev = &sh->dev[i];
4304             if (!test_bit(R5_OVERWRITE, &dev->flags) &&
4305                 i != sh->pd_idx && i != sh->qd_idx &&
4306                 !test_bit(R5_LOCKED, &dev->flags) &&
4307                 !(test_bit(R5_UPTODATE, &dev->flags) ||
4308                   test_bit(R5_Wantcompute, &dev->flags))) {
4309                 rcw++;
4310                 if (test_bit(R5_Insync, &dev->flags) &&
4311                     test_bit(STRIPE_PREREAD_ACTIVE,
4312                          &sh->state)) {
4313                     pr_debug("Read_old block "
4314                         "%d for Reconstruct\n", i);
4315                     set_bit(R5_LOCKED, &dev->flags);
4316                     set_bit(R5_Wantread, &dev->flags);
4317                     s->locked++;
4318                     qread++;
4319                 } else
4320                     set_bit(STRIPE_DELAYED, &sh->state);
4321             }
4322         }
4323         if (rcw && conf->mddev->queue)
4324             blk_add_trace_msg(conf->mddev->queue, "raid5 rcw %llu %d %d %d",
4325                       (unsigned long long)sh->sector,
4326                       rcw, qread, test_bit(STRIPE_DELAYED, &sh->state));
4327     }
4328
4329     if (rcw > disks && rmw > disks &&
4330         !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
4331         set_bit(STRIPE_DELAYED, &sh->state);
4332
4333     /* now if nothing is locked, and if we have enough data,
4334      * we can start a write request
4335      */
4336     /* since handle_stripe can be called at any time we need to handle the
4337      * case where a compute block operation has been submitted and then a
4338      * subsequent call wants to start a write request.  raid_run_ops only
4339      * handles the case where compute block and reconstruct are requested
4340      * simultaneously.  If this is not the case then new writes need to be
4341      * held off until the compute completes.
4342      */
4343     if ((s->req_compute || !test_bit(STRIPE_COMPUTE_RUN, &sh->state)) &&
4344         (s->locked == 0 && (rcw == 0 || rmw == 0) &&
4345          !test_bit(STRIPE_BIT_DELAY, &sh->state)))
4346         schedule_reconstruction(sh, s, rcw == 0, 0);
4347     return 0;
4348 }
4349
4350 static void handle_parity_checks5(struct r5conf *conf, struct stripe_head *sh,
4351                 struct stripe_head_state *s, int disks)
4352 {
4353     struct r5dev *dev = NULL;
4354
4355     BUG_ON(sh->batch_head);
4356     set_bit(STRIPE_HANDLE, &sh->state);
4357
4358     switch (sh->check_state) {
4359     case check_state_idle:
4360         /* start a new check operation if there are no failures */
4361         if (s->failed == 0) {
4362             BUG_ON(s->uptodate != disks);
4363             sh->check_state = check_state_run;
4364             set_bit(STRIPE_OP_CHECK, &s->ops_request);
4365             clear_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags);
4366             s->uptodate--;
4367             break;
4368         }
4369         dev = &sh->dev[s->failed_num[0]];
4370         fallthrough;
4371     case check_state_compute_result:
4372         sh->check_state = check_state_idle;
4373         if (!dev)
4374             dev = &sh->dev[sh->pd_idx];
4375
4376         /* check that a write has not made the stripe insync */
4377         if (test_bit(STRIPE_INSYNC, &sh->state))
4378             break;
4379
4380         /* either failed parity check, or recovery is happening */
4381         BUG_ON(!test_bit(R5_UPTODATE, &dev->flags));
4382         BUG_ON(s->uptodate != disks);
4383
4384         set_bit(R5_LOCKED, &dev->flags);
4385         s->locked++;
4386         set_bit(R5_Wantwrite, &dev->flags);
4387
4388         clear_bit(STRIPE_DEGRADED, &sh->state);
4389         set_bit(STRIPE_INSYNC, &sh->state);
4390         break;
4391     case check_state_run:
4392         break; /* we will be called again upon completion */
4393     case check_state_check_result:
4394         sh->check_state = check_state_idle;
4395
4396         /* if a failure occurred during the check operation, leave
4397          * STRIPE_INSYNC not set and let the stripe be handled again
4398          */
4399         if (s->failed)
4400             break;
4401
4402         /* handle a successful check operation, if parity is correct
4403          * we are done.  Otherwise update the mismatch count and repair
4404          * parity if !MD_RECOVERY_CHECK
4405          */
4406         if ((sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) == 0)
4407             /* parity is correct (on disc,
4408              * not in buffer any more)
4409              */
4410             set_bit(STRIPE_INSYNC, &sh->state);
4411         else {
4412             atomic64_add(RAID5_STRIPE_SECTORS(conf), &conf->mddev->resync_mismatches);
4413             if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery)) {
4414                 /* don't try to repair!! */
4415                 set_bit(STRIPE_INSYNC, &sh->state);
4416                 pr_warn_ratelimited("%s: mismatch sector in range "
4417                             "%llu-%llu\n", mdname(conf->mddev),
4418                             (unsigned long long) sh->sector,
4419                             (unsigned long long) sh->sector +
4420                             RAID5_STRIPE_SECTORS(conf));
4421             } else {
4422                 sh->check_state = check_state_compute_run;
4423                 set_bit(STRIPE_COMPUTE_RUN, &sh->state);
4424                 set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
4425                 set_bit(R5_Wantcompute,
4426                     &sh->dev[sh->pd_idx].flags);
4427                 sh->ops.target = sh->pd_idx;
4428                 sh->ops.target2 = -1;
4429                 s->uptodate++;
4430             }
4431         }
4432         break;
4433     case check_state_compute_run:
4434         break;
4435     default:
4436         pr_err("%s: unknown check_state: %d sector: %llu\n",
4437                __func__, sh->check_state,
4438                (unsigned long long) sh->sector);
4439         BUG();
4440     }
4441 }
4442
4443 static void handle_parity_checks6(struct r5conf *conf, struct stripe_head *sh,
4444                   struct stripe_head_state *s,
4445                   int disks)
4446 {
4447     int pd_idx = sh->pd_idx;
4448     int qd_idx = sh->qd_idx;
4449     struct r5dev *dev;
4450
4451     BUG_ON(sh->batch_head);
4452     set_bit(STRIPE_HANDLE, &sh->state);
4453
4454     BUG_ON(s->failed > 2);
4455
4456     /* Want to check and possibly repair P and Q.
4457      * However there could be one 'failed' device, in which
4458      * case we can only check one of them, possibly using the
4459      * other to generate missing data
4460      */
4461
4462     switch (sh->check_state) {
4463     case check_state_idle:
4464         /* start a new check operation if there are < 2 failures */
4465         if (s->failed == s->q_failed) {
4466             /* The only possible failed device holds Q, so it
4467              * makes sense to check P (If anything else were failed,
4468              * we would have used P to recreate it).
4469              */
4470             sh->check_state = check_state_run;
4471         }
4472         if (!s->q_failed && s->failed < 2) {
4473             /* Q is not failed, and we didn't use it to generate
4474              * anything, so it makes sense to check it
4475              */
4476             if (sh->check_state == check_state_run)
4477                 sh->check_state = check_state_run_pq;
4478             else
4479                 sh->check_state = check_state_run_q;
4480         }
4481
4482         /* discard potentially stale zero_sum_result */
4483         sh->ops.zero_sum_result = 0;
4484
4485         if (sh->check_state == check_state_run) {
4486             /* async_xor_zero_sum destroys the contents of P */
4487             clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
4488             s->uptodate--;
4489         }
4490         if (sh->check_state >= check_state_run &&
4491             sh->check_state <= check_state_run_pq) {
4492             /* async_syndrome_zero_sum preserves P and Q, so
4493              * no need to mark them !uptodate here
4494              */
4495             set_bit(STRIPE_OP_CHECK, &s->ops_request);
4496             break;
4497         }
4498
4499         /* we have 2-disk failure */
4500         BUG_ON(s->failed != 2);
4501         fallthrough;
4502     case check_state_compute_result:
4503         sh->check_state = check_state_idle;
4504
4505         /* check that a write has not made the stripe insync */
4506         if (test_bit(STRIPE_INSYNC, &sh->state))
4507             break;
4508
4509         /* now write out any block on a failed drive,
4510          * or P or Q if they were recomputed
4511          */
4512         dev = NULL;
4513         if (s->failed == 2) {
4514             dev = &sh->dev[s->failed_num[1]];
4515             s->locked++;
4516             set_bit(R5_LOCKED, &dev->flags);
4517             set_bit(R5_Wantwrite, &dev->flags);
4518         }
4519         if (s->failed >= 1) {
4520             dev = &sh->dev[s->failed_num[0]];
4521             s->locked++;
4522             set_bit(R5_LOCKED, &dev->flags);
4523             set_bit(R5_Wantwrite, &dev->flags);
4524         }
4525         if (sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) {
4526             dev = &sh->dev[pd_idx];
4527             s->locked++;
4528             set_bit(R5_LOCKED, &dev->flags);
4529             set_bit(R5_Wantwrite, &dev->flags);
4530         }
4531         if (sh->ops.zero_sum_result & SUM_CHECK_Q_RESULT) {
4532             dev = &sh->dev[qd_idx];
4533             s->locked++;
4534             set_bit(R5_LOCKED, &dev->flags);
4535             set_bit(R5_Wantwrite, &dev->flags);
4536         }
4537         if (WARN_ONCE(dev && !test_bit(R5_UPTODATE, &dev->flags),
4538                   "%s: disk%td not up to date\n",
4539                   mdname(conf->mddev),
4540                   dev - (struct r5dev *) &sh->dev)) {
4541             clear_bit(R5_LOCKED, &dev->flags);
4542             clear_bit(R5_Wantwrite, &dev->flags);
4543             s->locked--;
4544         }
4545         clear_bit(STRIPE_DEGRADED, &sh->state);
4546
4547         set_bit(STRIPE_INSYNC, &sh->state);
4548         break;
4549     case check_state_run:
4550     case check_state_run_q:
4551     case check_state_run_pq:
4552         break; /* we will be called again upon completion */
4553     case check_state_check_result:
4554         sh->check_state = check_state_idle;
4555
4556         /* handle a successful check operation, if parity is correct
4557          * we are done.  Otherwise update the mismatch count and repair
4558          * parity if !MD_RECOVERY_CHECK
4559          */
4560         if (sh->ops.zero_sum_result == 0) {
4561             /* both parities are correct */
4562             if (!s->failed)
4563                 set_bit(STRIPE_INSYNC, &sh->state);
4564             else {
4565                 /* in contrast to the raid5 case we can validate
4566                  * parity, but still have a failure to write
4567                  * back
4568                  */
4569                 sh->check_state = check_state_compute_result;
4570                 /* Returning at this point means that we may go
4571                  * off and bring p and/or q uptodate again so
4572                  * we make sure to check zero_sum_result again
4573                  * to verify if p or q need writeback
4574                  */
4575             }
4576         } else {
4577             atomic64_add(RAID5_STRIPE_SECTORS(conf), &conf->mddev->resync_mismatches);
4578             if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery)) {
4579                 /* don't try to repair!! */
4580                 set_bit(STRIPE_INSYNC, &sh->state);
4581                 pr_warn_ratelimited("%s: mismatch sector in range "
4582                             "%llu-%llu\n", mdname(conf->mddev),
4583                             (unsigned long long) sh->sector,
4584                             (unsigned long long) sh->sector +
4585                             RAID5_STRIPE_SECTORS(conf));
4586             } else {
4587                 int *target = &sh->ops.target;
4588
4589                 sh->ops.target = -1;
4590                 sh->ops.target2 = -1;
4591                 sh->check_state = check_state_compute_run;
4592                 set_bit(STRIPE_COMPUTE_RUN, &sh->state);
4593                 set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
4594                 if (sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) {
4595                     set_bit(R5_Wantcompute,
4596                         &sh->dev[pd_idx].flags);
4597                     *target = pd_idx;
4598                     target = &sh->ops.target2;
4599                     s->uptodate++;
4600                 }
4601                 if (sh->ops.zero_sum_result & SUM_CHECK_Q_RESULT) {
4602                     set_bit(R5_Wantcompute,
4603                         &sh->dev[qd_idx].flags);
4604                     *target = qd_idx;
4605                     s->uptodate++;
4606                 }
4607             }
4608         }
4609         break;
4610     case check_state_compute_run:
4611         break;
4612     default:
4613         pr_warn("%s: unknown check_state: %d sector: %llu\n",
4614             __func__, sh->check_state,
4615             (unsigned long long) sh->sector);
4616         BUG();
4617     }
4618 }
4619
4620 static void handle_stripe_expansion(struct r5conf *conf, struct stripe_head *sh)
4621 {
4622     int i;
4623
4624     /* We have read all the blocks in this stripe and now we need to
4625      * copy some of them into a target stripe for expand.
4626      */
4627     struct dma_async_tx_descriptor *tx = NULL;
4628     BUG_ON(sh->batch_head);
4629     clear_bit(STRIPE_EXPAND_SOURCE, &sh->state);
4630     for (i = 0; i < sh->disks; i++)
4631         if (i != sh->pd_idx && i != sh->qd_idx) {
4632             int dd_idx, j;
4633             struct stripe_head *sh2;
4634             struct async_submit_ctl submit;
4635
4636             sector_t bn = raid5_compute_blocknr(sh, i, 1);
4637             sector_t s = raid5_compute_sector(conf, bn, 0,
4638                               &dd_idx, NULL);
4639             sh2 = raid5_get_active_stripe(conf, s, 0, 1, 1);
4640             if (sh2 == NULL)
4641                 /* so far only the early blocks of this stripe
4642                  * have been requested.  When later blocks
4643                  * get requested, we will try again
4644                  */
4645                 continue;
4646             if (!test_bit(STRIPE_EXPANDING, &sh2->state) ||
4647                test_bit(R5_Expanded, &sh2->dev[dd_idx].flags)) {
4648                 /* must have already done this block */
4649                 raid5_release_stripe(sh2);
4650                 continue;
4651             }
4652
4653             /* place all the copies on one channel */
4654             init_async_submit(&submit, 0, tx, NULL, NULL, NULL);
4655             tx = async_memcpy(sh2->dev[dd_idx].page,
4656                       sh->dev[i].page, sh2->dev[dd_idx].offset,
4657                       sh->dev[i].offset, RAID5_STRIPE_SIZE(conf),
4658                       &submit);
4659
4660             set_bit(R5_Expanded, &sh2->dev[dd_idx].flags);
4661             set_bit(R5_UPTODATE, &sh2->dev[dd_idx].flags);
4662             for (j = 0; j < conf->raid_disks; j++)
4663                 if (j != sh2->pd_idx &&
4664                     j != sh2->qd_idx &&
4665                     !test_bit(R5_Expanded, &sh2->dev[j].flags))
4666                     break;
4667             if (j == conf->raid_disks) {
4668                 set_bit(STRIPE_EXPAND_READY, &sh2->state);
4669                 set_bit(STRIPE_HANDLE, &sh2->state);
4670             }
4671             raid5_release_stripe(sh2);
4672
4673         }
4674     /* done submitting copies, wait for them to complete */
4675     async_tx_quiesce(&tx);
4676 }
4677
4678 /*
4679  * handle_stripe - do things to a stripe.
4680  *
4681  * We lock the stripe by setting STRIPE_ACTIVE and then examine the
4682  * state of various bits to see what needs to be done.
4683  * Possible results:
4684  *    return some read requests which now have data
4685  *    return some write requests which are safely on storage
4686  *    schedule a read on some buffers
4687  *    schedule a write of some buffers
4688  *    return confirmation of parity correctness
4689  *
4690  */
4691
4692 static void analyse_stripe(struct stripe_head *sh, struct stripe_head_state *s)
4693 {
4694     struct r5conf *conf = sh->raid_conf;
4695     int disks = sh->disks;
4696     struct r5dev *dev;
4697     int i;
4698     int do_recovery = 0;
4699
4700     memset(s, 0, sizeof(*s));
4701
4702     s->expanding = test_bit(STRIPE_EXPAND_SOURCE, &sh->state) && !sh->batch_head;
4703     s->expanded = test_bit(STRIPE_EXPAND_READY, &sh->state) && !sh->batch_head;
4704     s->failed_num[0] = -1;
4705     s->failed_num[1] = -1;
4706     s->log_failed = r5l_log_disk_error(conf);
4707
4708     /* Now to look around and see what can be done */
4709     rcu_read_lock();
4710     for (i=disks; i--; ) {
4711         struct md_rdev *rdev;
4712         sector_t first_bad;
4713         int bad_sectors;
4714         int is_bad = 0;
4715
4716         dev = &sh->dev[i];
4717
4718         pr_debug("check %d: state 0x%lx read %p write %p written %p\n",
4719              i, dev->flags,
4720              dev->toread, dev->towrite, dev->written);
4721         /* maybe we can reply to a read
4722          *
4723          * new wantfill requests are only permitted while
4724          * ops_complete_biofill is guaranteed to be inactive
4725          */
4726         if (test_bit(R5_UPTODATE, &dev->flags) && dev->toread &&
4727             !test_bit(STRIPE_BIOFILL_RUN, &sh->state))
4728             set_bit(R5_Wantfill, &dev->flags);
4729
4730         /* now count some things */
4731         if (test_bit(R5_LOCKED, &dev->flags))
4732             s->locked++;
4733         if (test_bit(R5_UPTODATE, &dev->flags))
4734             s->uptodate++;
4735         if (test_bit(R5_Wantcompute, &dev->flags)) {
4736             s->compute++;
4737             BUG_ON(s->compute > 2);
4738         }
4739
4740         if (test_bit(R5_Wantfill, &dev->flags))
4741             s->to_fill++;
4742         else if (dev->toread)
4743             s->to_read++;
4744         if (dev->towrite) {
4745             s->to_write++;
4746             if (!test_bit(R5_OVERWRITE, &dev->flags))
4747                 s->non_overwrite++;
4748         }
4749         if (dev->written)
4750             s->written++;
4751         /* Prefer to use the replacement for reads, but only
4752          * if it is recovered enough and has no bad blocks.
4753          */
4754         rdev = rcu_dereference(conf->disks[i].replacement);
4755         if (rdev && !test_bit(Faulty, &rdev->flags) &&
4756             rdev->recovery_offset >= sh->sector + RAID5_STRIPE_SECTORS(conf) &&
4757             !is_badblock(rdev, sh->sector, RAID5_STRIPE_SECTORS(conf),
4758                  &first_bad, &bad_sectors))
4759             set_bit(R5_ReadRepl, &dev->flags);
4760         else {
4761             if (rdev && !test_bit(Faulty, &rdev->flags))
4762                 set_bit(R5_NeedReplace, &dev->flags);
4763             else
4764                 clear_bit(R5_NeedReplace, &dev->flags);
4765             rdev = rcu_dereference(conf->disks[i].rdev);
4766             clear_bit(R5_ReadRepl, &dev->flags);
4767         }
4768         if (rdev && test_bit(Faulty, &rdev->flags))
4769             rdev = NULL;
4770         if (rdev) {
4771             is_bad = is_badblock(rdev, sh->sector, RAID5_STRIPE_SECTORS(conf),
4772                          &first_bad, &bad_sectors);
4773             if (s->blocked_rdev == NULL
4774                 && (test_bit(Blocked, &rdev->flags)
4775                 || is_bad < 0)) {
4776                 if (is_bad < 0)
4777                     set_bit(BlockedBadBlocks,
4778                         &rdev->flags);
4779                 s->blocked_rdev = rdev;
4780                 atomic_inc(&rdev->nr_pending);
4781             }
4782         }
4783         clear_bit(R5_Insync, &dev->flags);
4784         if (!rdev)
4785             /* Not in-sync */;
4786         else if (is_bad) {
4787             /* also not in-sync */
4788             if (!test_bit(WriteErrorSeen, &rdev->flags) &&
4789                 test_bit(R5_UPTODATE, &dev->flags)) {
4790                 /* treat as in-sync, but with a read error
4791                  * which we can now try to correct
4792                  */
4793                 set_bit(R5_Insync, &dev->flags);
4794                 set_bit(R5_ReadError, &dev->flags);
4795             }
4796         } else if (test_bit(In_sync, &rdev->flags))
4797             set_bit(R5_Insync, &dev->flags);
4798         else if (sh->sector + RAID5_STRIPE_SECTORS(conf) <= rdev->recovery_offset)
4799             /* in sync if before recovery_offset */
4800             set_bit(R5_Insync, &dev->flags);
4801         else if (test_bit(R5_UPTODATE, &dev->flags) &&
4802              test_bit(R5_Expanded, &dev->flags))
4803             /* If we've reshaped into here, we assume it is Insync.
4804              * We will shortly update recovery_offset to make
4805              * it official.
4806              */
4807             set_bit(R5_Insync, &dev->flags);
4808
4809         if (test_bit(R5_WriteError, &dev->flags)) {
4810             /* This flag does not apply to '.replacement'
4811              * only to .rdev, so make sure to check that*/
4812             struct md_rdev *rdev2 = rcu_dereference(
4813                 conf->disks[i].rdev);
4814             if (rdev2 == rdev)
4815                 clear_bit(R5_Insync, &dev->flags);
4816             if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
4817                 s->handle_bad_blocks = 1;
4818                 atomic_inc(&rdev2->nr_pending);
4819             } else
4820                 clear_bit(R5_WriteError, &dev->flags);
4821         }
4822         if (test_bit(R5_MadeGood, &dev->flags)) {
4823             /* This flag does not apply to '.replacement'
4824              * only to .rdev, so make sure to check that*/
4825             struct md_rdev *rdev2 = rcu_dereference(
4826                 conf->disks[i].rdev);
4827             if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
4828                 s->handle_bad_blocks = 1;
4829                 atomic_inc(&rdev2->nr_pending);
4830             } else
4831                 clear_bit(R5_MadeGood, &dev->flags);
4832         }
4833         if (test_bit(R5_MadeGoodRepl, &dev->flags)) {
4834             struct md_rdev *rdev2 = rcu_dereference(
4835                 conf->disks[i].replacement);
4836             if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
4837                 s->handle_bad_blocks = 1;
4838                 atomic_inc(&rdev2->nr_pending);
4839             } else
4840                 clear_bit(R5_MadeGoodRepl, &dev->flags);
4841         }
4842         if (!test_bit(R5_Insync, &dev->flags)) {
4843             /* The ReadError flag will just be confusing now */
4844             clear_bit(R5_ReadError, &dev->flags);
4845             clear_bit(R5_ReWrite, &dev->flags);
4846         }
4847         if (test_bit(R5_ReadError, &dev->flags))
4848             clear_bit(R5_Insync, &dev->flags);
4849         if (!test_bit(R5_Insync, &dev->flags)) {
4850             if (s->failed < 2)
4851                 s->failed_num[s->failed] = i;
4852             s->failed++;
4853             if (rdev && !test_bit(Faulty, &rdev->flags))
4854                 do_recovery = 1;
4855             else if (!rdev) {
4856                 rdev = rcu_dereference(
4857                     conf->disks[i].replacement);
4858                 if (rdev && !test_bit(Faulty, &rdev->flags))
4859                     do_recovery = 1;
4860             }
4861         }
4862
4863         if (test_bit(R5_InJournal, &dev->flags))
4864             s->injournal++;
4865         if (test_bit(R5_InJournal, &dev->flags) && dev->written)
4866             s->just_cached++;
4867     }
4868     if (test_bit(STRIPE_SYNCING, &sh->state)) {
4869         /* If there is a failed device being replaced,
4870          *     we must be recovering.
4871          * else if we are after recovery_cp, we must be syncing
4872          * else if MD_RECOVERY_REQUESTED is set, we also are syncing.
4873          * else we can only be replacing
4874          * sync and recovery both need to read all devices, and so
4875          * use the same flag.
4876          */
4877         if (do_recovery ||
4878             sh->sector >= conf->mddev->recovery_cp ||
4879             test_bit(MD_RECOVERY_REQUESTED, &(conf->mddev->recovery)))
4880             s->syncing = 1;
4881         else
4882             s->replacing = 1;
4883     }
4884     rcu_read_unlock();
4885 }
4886
4887 /*
4888  * Return '1' if this is a member of batch, or '0' if it is a lone stripe or
4889  * a head which can now be handled.
4890  */
4891 static int clear_batch_ready(struct stripe_head *sh)
4892 {
4893     struct stripe_head *tmp;
4894     if (!test_and_clear_bit(STRIPE_BATCH_READY, &sh->state))
4895         return (sh->batch_head && sh->batch_head != sh);
4896     spin_lock(&sh->stripe_lock);
4897     if (!sh->batch_head) {
4898         spin_unlock(&sh->stripe_lock);
4899         return 0;
4900     }
4901
4902     /*
4903      * this stripe could be added to a batch list before we check
4904      * BATCH_READY, skips it
4905      */
4906     if (sh->batch_head != sh) {
4907         spin_unlock(&sh->stripe_lock);
4908         return 1;
4909     }
4910     spin_lock(&sh->batch_lock);
4911     list_for_each_entry(tmp, &sh->batch_list, batch_list)
4912         clear_bit(STRIPE_BATCH_READY, &tmp->state);
4913     spin_unlock(&sh->batch_lock);
4914     spin_unlock(&sh->stripe_lock);
4915
4916     /*
4917      * BATCH_READY is cleared, no new stripes can be added.
4918      * batch_list can be accessed without lock
4919      */
4920     return 0;
4921 }
4922
4923 static void break_stripe_batch_list(struct stripe_head *head_sh,
4924                     unsigned long handle_flags)
4925 {
4926     struct stripe_head *sh, *next;
4927     int i;
4928     int do_wakeup = 0;
4929
4930     list_for_each_entry_safe(sh, next, &head_sh->batch_list, batch_list) {
4931
4932         list_del_init(&sh->batch_list);
4933
4934         WARN_ONCE(sh->state & ((1 << STRIPE_ACTIVE) |
4935                       (1 << STRIPE_SYNCING) |
4936                       (1 << STRIPE_REPLACED) |
4937                       (1 << STRIPE_DELAYED) |
4938                       (1 << STRIPE_BIT_DELAY) |
4939                       (1 << STRIPE_FULL_WRITE) |
4940                       (1 << STRIPE_BIOFILL_RUN) |
4941                       (1 << STRIPE_COMPUTE_RUN)  |
4942                       (1 << STRIPE_DISCARD) |
4943                       (1 << STRIPE_BATCH_READY) |
4944                       (1 << STRIPE_BATCH_ERR) |
4945                       (1 << STRIPE_BITMAP_PENDING)),
4946             "stripe state: %lx\n", sh->state);
4947         WARN_ONCE(head_sh->state & ((1 << STRIPE_DISCARD) |
4948                           (1 << STRIPE_REPLACED)),
4949             "head stripe state: %lx\n", head_sh->state);
4950
4951         set_mask_bits(&sh->state, ~(STRIPE_EXPAND_SYNC_FLAGS |
4952                         (1 << STRIPE_PREREAD_ACTIVE) |
4953                         (1 << STRIPE_DEGRADED) |
4954                         (1 << STRIPE_ON_UNPLUG_LIST)),
4955                   head_sh->state & (1 << STRIPE_INSYNC));
4956
4957         sh->check_state = head_sh->check_state;
4958         sh->reconstruct_state = head_sh->reconstruct_state;
4959         spin_lock_irq(&sh->stripe_lock);
4960         sh->batch_head = NULL;
4961         spin_unlock_irq(&sh->stripe_lock);
4962         for (i = 0; i < sh->disks; i++) {
4963             if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
4964                 do_wakeup = 1;
4965             sh->dev[i].flags = head_sh->dev[i].flags &
4966                 (~((1 << R5_WriteError) | (1 << R5_Overlap)));
4967         }
4968         if (handle_flags == 0 ||
4969             sh->state & handle_flags)
4970             set_bit(STRIPE_HANDLE, &sh->state);
4971         raid5_release_stripe(sh);
4972     }
4973     spin_lock_irq(&head_sh->stripe_lock);
4974     head_sh->batch_head = NULL;
4975     spin_unlock_irq(&head_sh->stripe_lock);
4976     for (i = 0; i < head_sh->disks; i++)
4977         if (test_and_clear_bit(R5_Overlap, &head_sh->dev[i].flags))
4978             do_wakeup = 1;
4979     if (head_sh->state & handle_flags)
4980         set_bit(STRIPE_HANDLE, &head_sh->state);
4981
4982     if (do_wakeup)
4983         wake_up(&head_sh->raid_conf->wait_for_overlap);
4984 }
4985
4986 static void handle_stripe(struct stripe_head *sh)
4987 {
4988     struct stripe_head_state s;
4989     struct r5conf *conf = sh->raid_conf;
4990     int i;
4991     int prexor;
4992     int disks = sh->disks;
4993     struct r5dev *pdev, *qdev;
4994
4995     clear_bit(STRIPE_HANDLE, &sh->state);
4996
4997     /*
4998      * handle_stripe should not continue handle the batched stripe, only
4999      * the head of batch list or lone stripe can continue. Otherwise we
5000      * could see break_stripe_batch_list warns about the STRIPE_ACTIVE
5001      * is set for the batched stripe.
5002      */
5003     if (clear_batch_ready(sh))
5004         return;
5005
5006     if (test_and_set_bit_lock(STRIPE_ACTIVE, &sh->state)) {
5007         /* already being handled, ensure it gets handled
5008          * again when current action finishes */
5009         set_bit(STRIPE_HANDLE, &sh->state);
5010         return;
5011     }
5012
5013     if (test_and_clear_bit(STRIPE_BATCH_ERR, &sh->state))
5014         break_stripe_batch_list(sh, 0);
5015
5016     if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state) && !sh->batch_head) {
5017         spin_lock(&sh->stripe_lock);
5018         /*
5019          * Cannot process 'sync' concurrently with 'discard'.
5020          * Flush data in r5cache before 'sync'.
5021          */
5022         if (!test_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state) &&
5023             !test_bit(STRIPE_R5C_FULL_STRIPE, &sh->state) &&
5024             !test_bit(STRIPE_DISCARD, &sh->state) &&
5025             test_and_clear_bit(STRIPE_SYNC_REQUESTED, &sh->state)) {
5026             set_bit(STRIPE_SYNCING, &sh->state);
5027             clear_bit(STRIPE_INSYNC, &sh->state);
5028             clear_bit(STRIPE_REPLACED, &sh->state);
5029         }
5030         spin_unlock(&sh->stripe_lock);
5031     }
5032     clear_bit(STRIPE_DELAYED, &sh->state);
5033
5034     pr_debug("handling stripe %llu, state=%#lx cnt=%d, "
5035         "pd_idx=%d, qd_idx=%d\n, check:%d, reconstruct:%d\n",
5036            (unsigned long long)sh->sector, sh->state,
5037            atomic_read(&sh->count), sh->pd_idx, sh->qd_idx,
5038            sh->check_state, sh->reconstruct_state);
5039
5040     analyse_stripe(sh, &s);
5041
5042     if (test_bit(STRIPE_LOG_TRAPPED, &sh->state))
5043         goto finish;
5044
5045     if (s.handle_bad_blocks ||
5046         test_bit(MD_SB_CHANGE_PENDING, &conf->mddev->sb_flags)) {
5047         set_bit(STRIPE_HANDLE, &sh->state);
5048         goto finish;
5049     }
5050
5051     if (unlikely(s.blocked_rdev)) {
5052         if (s.syncing || s.expanding || s.expanded ||
5053             s.replacing || s.to_write || s.written) {
5054             set_bit(STRIPE_HANDLE, &sh->state);
5055             goto finish;
5056         }
5057         /* There is nothing for the blocked_rdev to block */
5058         rdev_dec_pending(s.blocked_rdev, conf->mddev);
5059         s.blocked_rdev = NULL;
5060     }
5061
5062     if (s.to_fill && !test_bit(STRIPE_BIOFILL_RUN, &sh->state)) {
5063         set_bit(STRIPE_OP_BIOFILL, &s.ops_request);
5064         set_bit(STRIPE_BIOFILL_RUN, &sh->state);
5065     }
5066
5067     pr_debug("locked=%d uptodate=%d to_read=%d"
5068            " to_write=%d failed=%d failed_num=%d,%d\n",
5069            s.locked, s.uptodate, s.to_read, s.to_write, s.failed,
5070            s.failed_num[0], s.failed_num[1]);
5071     /*
5072      * check if the array has lost more than max_degraded devices and,
5073      * if so, some requests might need to be failed.
5074      *
5075      * When journal device failed (log_failed), we will only process
5076      * the stripe if there is data need write to raid disks
5077      */
5078     if (s.failed > conf->max_degraded ||
5079         (s.log_failed && s.injournal == 0)) {
5080         sh->check_state = 0;
5081         sh->reconstruct_state = 0;
5082         break_stripe_batch_list(sh, 0);
5083         if (s.to_read+s.to_write+s.written)
5084             handle_failed_stripe(conf, sh, &s, disks);
5085         if (s.syncing + s.replacing)
5086             handle_failed_sync(conf, sh, &s);
5087     }
5088
5089     /* Now we check to see if any write operations have recently
5090      * completed
5091      */
5092     prexor = 0;
5093     if (sh->reconstruct_state == reconstruct_state_prexor_drain_result)
5094         prexor = 1;
5095     if (sh->reconstruct_state == reconstruct_state_drain_result ||
5096         sh->reconstruct_state == reconstruct_state_prexor_drain_result) {
5097         sh->reconstruct_state = reconstruct_state_idle;
5098
5099         /* All the 'written' buffers and the parity block are ready to
5100          * be written back to disk
5101          */
5102         BUG_ON(!test_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags) &&
5103                !test_bit(R5_Discard, &sh->dev[sh->pd_idx].flags));
5104         BUG_ON(sh->qd_idx >= 0 &&
5105                !test_bit(R5_UPTODATE, &sh->dev[sh->qd_idx].flags) &&
5106                !test_bit(R5_Discard, &sh->dev[sh->qd_idx].flags));
5107         for (i = disks; i--; ) {
5108             struct r5dev *dev = &sh->dev[i];
5109             if (test_bit(R5_LOCKED, &dev->flags) &&
5110                 (i == sh->pd_idx || i == sh->qd_idx ||
5111                  dev->written || test_bit(R5_InJournal,
5112                               &dev->flags))) {
5113                 pr_debug("Writing block %d\n", i);
5114                 set_bit(R5_Wantwrite, &dev->flags);
5115                 if (prexor)
5116                     continue;
5117                 if (s.failed > 1)
5118                     continue;
5119                 if (!test_bit(R5_Insync, &dev->flags) ||
5120                     ((i == sh->pd_idx || i == sh->qd_idx)  &&
5121                      s.failed == 0))
5122                     set_bit(STRIPE_INSYNC, &sh->state);
5123             }
5124         }
5125         if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
5126             s.dec_preread_active = 1;
5127     }
5128
5129     /*
5130      * might be able to return some write requests if the parity blocks
5131      * are safe, or on a failed drive
5132      */
5133     pdev = &sh->dev[sh->pd_idx];
5134     s.p_failed = (s.failed >= 1 && s.failed_num[0] == sh->pd_idx)
5135         || (s.failed >= 2 && s.failed_num[1] == sh->pd_idx);
5136     qdev = &sh->dev[sh->qd_idx];
5137     s.q_failed = (s.failed >= 1 && s.failed_num[0] == sh->qd_idx)
5138         || (s.failed >= 2 && s.failed_num[1] == sh->qd_idx)
5139         || conf->level < 6;
5140
5141     if (s.written &&
5142         (s.p_failed || ((test_bit(R5_Insync, &pdev->flags)
5143                  && !test_bit(R5_LOCKED, &pdev->flags)
5144                  && (test_bit(R5_UPTODATE, &pdev->flags) ||
5145                  test_bit(R5_Discard, &pdev->flags))))) &&
5146         (s.q_failed || ((test_bit(R5_Insync, &qdev->flags)
5147                  && !test_bit(R5_LOCKED, &qdev->flags)
5148                  && (test_bit(R5_UPTODATE, &qdev->flags) ||
5149                  test_bit(R5_Discard, &qdev->flags))))))
5150         handle_stripe_clean_event(conf, sh, disks);
5151
5152     if (s.just_cached)
5153         r5c_handle_cached_data_endio(conf, sh, disks);
5154     log_stripe_write_finished(sh);
5155
5156     /* Now we might consider reading some blocks, either to check/generate
5157      * parity, or to satisfy requests
5158      * or to load a block that is being partially written.
5159      */
5160     if (s.to_read || s.non_overwrite
5161         || (s.to_write && s.failed)
5162         || (s.syncing && (s.uptodate + s.compute < disks))
5163         || s.replacing
5164         || s.expanding)
5165         handle_stripe_fill(sh, &s, disks);
5166
5167     /*
5168      * When the stripe finishes full journal write cycle (write to journal
5169      * and raid disk), this is the clean up procedure so it is ready for
5170      * next operation.
5171      */
5172     r5c_finish_stripe_write_out(conf, sh, &s);
5173
5174     /*
5175      * Now to consider new write requests, cache write back and what else,
5176      * if anything should be read.  We do not handle new writes when:
5177      * 1/ A 'write' operation (copy+xor) is already in flight.
5178      * 2/ A 'check' operation is in flight, as it may clobber the parity
5179      *    block.
5180      * 3/ A r5c cache log write is in flight.
5181      */
5182
5183     if (!sh->reconstruct_state && !sh->check_state && !sh->log_io) {
5184         if (!r5c_is_writeback(conf->log)) {
5185             if (s.to_write)
5186                 handle_stripe_dirtying(conf, sh, &s, disks);
5187         } else { /* write back cache */
5188             int ret = 0;
5189
5190             /* First, try handle writes in caching phase */
5191             if (s.to_write)
5192                 ret = r5c_try_caching_write(conf, sh, &s,
5193                                 disks);
5194             /*
5195              * If caching phase failed: ret == -EAGAIN
5196              *    OR
5197              * stripe under reclaim: !caching && injournal
5198              *
5199              * fall back to handle_stripe_dirtying()
5200              */
5201             if (ret == -EAGAIN ||
5202                 /* stripe under reclaim: !caching && injournal */
5203                 (!test_bit(STRIPE_R5C_CACHING, &sh->state) &&
5204                  s.injournal > 0)) {
5205                 ret = handle_stripe_dirtying(conf, sh, &s,
5206                                  disks);
5207                 if (ret == -EAGAIN)
5208                     goto finish;
5209             }
5210         }
5211     }
5212
5213     /* maybe we need to check and possibly fix the parity for this stripe
5214      * Any reads will already have been scheduled, so we just see if enough
5215      * data is available.  The parity check is held off while parity
5216      * dependent operations are in flight.
5217      */
5218     if (sh->check_state ||
5219         (s.syncing && s.locked == 0 &&
5220          !test_bit(STRIPE_COMPUTE_RUN, &sh->state) &&
5221          !test_bit(STRIPE_INSYNC, &sh->state))) {
5222         if (conf->level == 6)
5223             handle_parity_checks6(conf, sh, &s, disks);
5224         else
5225             handle_parity_checks5(conf, sh, &s, disks);
5226     }
5227
5228     if ((s.replacing || s.syncing) && s.locked == 0
5229         && !test_bit(STRIPE_COMPUTE_RUN, &sh->state)
5230         && !test_bit(STRIPE_REPLACED, &sh->state)) {
5231         /* Write out to replacement devices where possible */
5232         for (i = 0; i < conf->raid_disks; i++)
5233             if (test_bit(R5_NeedReplace, &sh->dev[i].flags)) {
5234                 WARN_ON(!test_bit(R5_UPTODATE, &sh->dev[i].flags));
5235                 set_bit(R5_WantReplace, &sh->dev[i].flags);
5236                 set_bit(R5_LOCKED, &sh->dev[i].flags);
5237                 s.locked++;
5238             }
5239         if (s.replacing)
5240             set_bit(STRIPE_INSYNC, &sh->state);
5241         set_bit(STRIPE_REPLACED, &sh->state);
5242     }
5243     if ((s.syncing || s.replacing) && s.locked == 0 &&
5244         !test_bit(STRIPE_COMPUTE_RUN, &sh->state) &&
5245         test_bit(STRIPE_INSYNC, &sh->state)) {
5246         md_done_sync(conf->mddev, RAID5_STRIPE_SECTORS(conf), 1);
5247         clear_bit(STRIPE_SYNCING, &sh->state);
5248         if (test_and_clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags))
5249             wake_up(&conf->wait_for_overlap);
5250     }
5251
5252     /* If the failed drives are just a ReadError, then we might need
5253      * to progress the repair/check process
5254      */
5255     if (s.failed <= conf->max_degraded && !conf->mddev->ro)
5256         for (i = 0; i < s.failed; i++) {
5257             struct r5dev *dev = &sh->dev[s.failed_num[i]];
5258             if (test_bit(R5_ReadError, &dev->flags)
5259                 && !test_bit(R5_LOCKED, &dev->flags)
5260                 && test_bit(R5_UPTODATE, &dev->flags)
5261                 ) {
5262                 if (!test_bit(R5_ReWrite, &dev->flags)) {
5263                     set_bit(R5_Wantwrite, &dev->flags);
5264                     set_bit(R5_ReWrite, &dev->flags);
5265                 } else
5266                     /* let's read it back */
5267                     set_bit(R5_Wantread, &dev->flags);
5268                 set_bit(R5_LOCKED, &dev->flags);
5269                 s.locked++;
5270             }
5271         }
5272
5273     /* Finish reconstruct operations initiated by the expansion process */
5274     if (sh->reconstruct_state == reconstruct_state_result) {
5275         struct stripe_head *sh_src
5276             = raid5_get_active_stripe(conf, sh->sector, 1, 1, 1);
5277         if (sh_src && test_bit(STRIPE_EXPAND_SOURCE, &sh_src->state)) {
5278             /* sh cannot be written until sh_src has been read.
5279              * so arrange for sh to be delayed a little
5280              */
5281             set_bit(STRIPE_DELAYED, &sh->state);
5282             set_bit(STRIPE_HANDLE, &sh->state);
5283             if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE,
5284                           &sh_src->state))
5285                 atomic_inc(&conf->preread_active_stripes);
5286             raid5_release_stripe(sh_src);
5287             goto finish;
5288         }
5289         if (sh_src)
5290             raid5_release_stripe(sh_src);
5291
5292         sh->reconstruct_state = reconstruct_state_idle;
5293         clear_bit(STRIPE_EXPANDING, &sh->state);
5294         for (i = conf->raid_disks; i--; ) {
5295             set_bit(R5_Wantwrite, &sh->dev[i].flags);
5296             set_bit(R5_LOCKED, &sh->dev[i].flags);
5297             s.locked++;
5298         }
5299     }
5300
5301     if (s.expanded && test_bit(STRIPE_EXPANDING, &sh->state) &&
5302         !sh->reconstruct_state) {
5303         /* Need to write out all blocks after computing parity */
5304         sh->disks = conf->raid_disks;
5305         stripe_set_idx(sh->sector, conf, 0, sh);
5306         schedule_reconstruction(sh, &s, 1, 1);
5307     } else if (s.expanded && !sh->reconstruct_state && s.locked == 0) {
5308         clear_bit(STRIPE_EXPAND_READY, &sh->state);
5309         atomic_dec(&conf->reshape_stripes);
5310         wake_up(&conf->wait_for_overlap);
5311         md_done_sync(conf->mddev, RAID5_STRIPE_SECTORS(conf), 1);
5312     }
5313
5314     if (s.expanding && s.locked == 0 &&
5315         !test_bit(STRIPE_COMPUTE_RUN, &sh->state))
5316         handle_stripe_expansion(conf, sh);
5317
5318 finish:
5319     /* wait for this device to become unblocked */
5320     if (unlikely(s.blocked_rdev)) {
5321         if (conf->mddev->external)
5322             md_wait_for_blocked_rdev(s.blocked_rdev,
5323                          conf->mddev);
5324         else
5325             /* Internal metadata will immediately
5326              * be written by raid5d, so we don't
5327              * need to wait here.
5328              */
5329             rdev_dec_pending(s.blocked_rdev,
5330                      conf->mddev);
5331     }
5332
5333     if (s.handle_bad_blocks)
5334         for (i = disks; i--; ) {
5335             struct md_rdev *rdev;
5336             struct r5dev *dev = &sh->dev[i];
5337             if (test_and_clear_bit(R5_WriteError, &dev->flags)) {
5338                 /* We own a safe reference to the rdev */
5339                 rdev = rdev_pend_deref(conf->disks[i].rdev);
5340                 if (!rdev_set_badblocks(rdev, sh->sector,
5341                             RAID5_STRIPE_SECTORS(conf), 0))
5342                     md_error(conf->mddev, rdev);
5343                 rdev_dec_pending(rdev, conf->mddev);
5344             }
5345             if (test_and_clear_bit(R5_MadeGood, &dev->flags)) {
5346                 rdev = rdev_pend_deref(conf->disks[i].rdev);
5347                 rdev_clear_badblocks(rdev, sh->sector,
5348                              RAID5_STRIPE_SECTORS(conf), 0);
5349                 rdev_dec_pending(rdev, conf->mddev);
5350             }
5351             if (test_and_clear_bit(R5_MadeGoodRepl, &dev->flags)) {
5352                 rdev = rdev_pend_deref(conf->disks[i].replacement);
5353                 if (!rdev)
5354                     /* rdev have been moved down */
5355                     rdev = rdev_pend_deref(conf->disks[i].rdev);
5356                 rdev_clear_badblocks(rdev, sh->sector,
5357                              RAID5_STRIPE_SECTORS(conf), 0);
5358                 rdev_dec_pending(rdev, conf->mddev);
5359             }
5360         }
5361
5362     if (s.ops_request)
5363         raid_run_ops(sh, s.ops_request);
5364
5365     ops_run_io(sh, &s);
5366
5367     if (s.dec_preread_active) {
5368         /* We delay this until after ops_run_io so that if make_request
5369          * is waiting on a flush, it won't continue until the writes
5370          * have actually been submitted.
5371          */
5372         atomic_dec(&conf->preread_active_stripes);
5373         if (atomic_read(&conf->preread_active_stripes) <
5374             IO_THRESHOLD)
5375             md_wakeup_thread(conf->mddev->thread);
5376     }
5377
5378     clear_bit_unlock(STRIPE_ACTIVE, &sh->state);
5379 }
5380
5381 static void raid5_activate_delayed(struct r5conf *conf)
5382     __must_hold(&conf->device_lock)
5383 {
5384     if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD) {
5385         while (!list_empty(&conf->delayed_list)) {
5386             struct list_head *l = conf->delayed_list.next;
5387             struct stripe_head *sh;
5388             sh = list_entry(l, struct stripe_head, lru);
5389             list_del_init(l);
5390             clear_bit(STRIPE_DELAYED, &sh->state);
5391             if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
5392                 atomic_inc(&conf->preread_active_stripes);
5393             list_add_tail(&sh->lru, &conf->hold_list);
5394             raid5_wakeup_stripe_thread(sh);
5395         }
5396     }
5397 }
5398
5399 static void activate_bit_delay(struct r5conf *conf,
5400         struct list_head *temp_inactive_list)
5401     __must_hold(&conf->device_lock)
5402 {
5403     struct list_head head;
5404     list_add(&head, &conf->bitmap_list);
5405     list_del_init(&conf->bitmap_list);
5406     while (!list_empty(&head)) {
5407         struct stripe_head *sh = list_entry(head.next, struct stripe_head, lru);
5408         int hash;
5409         list_del_init(&sh->lru);
5410         atomic_inc(&sh->count);
5411         hash = sh->hash_lock_index;
5412         __release_stripe(conf, sh, &temp_inactive_list[hash]);
5413     }
5414 }
5415
5416 static int in_chunk_boundary(struct mddev *mddev, struct bio *bio)
5417 {
5418     struct r5conf *conf = mddev->private;
5419     sector_t sector = bio->bi_iter.bi_sector;
5420     unsigned int chunk_sectors;
5421     unsigned int bio_sectors = bio_sectors(bio);
5422
5423     chunk_sectors = min(conf->chunk_sectors, conf->prev_chunk_sectors);
5424     return  chunk_sectors >=
5425         ((sector & (chunk_sectors - 1)) + bio_sectors);
5426 }
5427
5428 /*
5429  *  add bio to the retry LIFO  ( in O(1) ... we are in interrupt )
5430  *  later sampled by raid5d.
5431  */
5432 static void add_bio_to_retry(struct bio *bi,struct r5conf *conf)
5433 {
5434     unsigned long flags;
5435
5436     spin_lock_irqsave(&conf->device_lock, flags);
5437
5438     bi->bi_next = conf->retry_read_aligned_list;
5439     conf->retry_read_aligned_list = bi;
5440
5441     spin_unlock_irqrestore(&conf->device_lock, flags);
5442     md_wakeup_thread(conf->mddev->thread);
5443 }
5444
5445 static struct bio *remove_bio_from_retry(struct r5conf *conf,
5446                      unsigned int *offset)
5447 {
5448     struct bio *bi;
5449
5450     bi = conf->retry_read_aligned;
5451     if (bi) {
5452         *offset = conf->retry_read_offset;
5453         conf->retry_read_aligned = NULL;
5454         return bi;
5455     }
5456     bi = conf->retry_read_aligned_list;
5457     if(bi) {
5458         conf->retry_read_aligned_list = bi->bi_next;
5459         bi->bi_next = NULL;
5460         *offset = 0;
5461     }
5462
5463     return bi;
5464 }
5465
5466 /*
5467  *  The "raid5_align_endio" should check if the read succeeded and if it
5468  *  did, call bio_endio on the original bio (having bio_put the new bio
5469  *  first).
5470  *  If the read failed..
5471  */
5472 static void raid5_align_endio(struct bio *bi)
5473 {
5474     struct md_io_acct *md_io_acct = bi->bi_private;
5475     struct bio *raid_bi = md_io_acct->orig_bio;
5476     struct mddev *mddev;
5477     struct r5conf *conf;
5478     struct md_rdev *rdev;
5479     blk_status_t error = bi->bi_status;
5480     unsigned long start_time = md_io_acct->start_time;
5481
5482     bio_put(bi);
5483
5484     rdev = (void*)raid_bi->bi_next;
5485     raid_bi->bi_next = NULL;
5486     mddev = rdev->mddev;
5487     conf = mddev->private;
5488
5489     rdev_dec_pending(rdev, conf->mddev);
5490
5491     if (!error) {
5492         if (blk_queue_io_stat(raid_bi->bi_bdev->bd_disk->queue))
5493             bio_end_io_acct(raid_bi, start_time);
5494         bio_endio(raid_bi);
5495         if (atomic_dec_and_test(&conf->active_aligned_reads))
5496             wake_up(&conf->wait_for_quiescent);
5497         return;
5498     }
5499
5500     pr_debug("raid5_align_endio : io error...handing IO for a retry\n");
5501
5502     add_bio_to_retry(raid_bi, conf);
5503 }
5504
5505 static int raid5_read_one_chunk(struct mddev *mddev, struct bio *raid_bio)
5506 {
5507     struct r5conf *conf = mddev->private;
5508     struct bio *align_bio;
5509     struct md_rdev *rdev;
5510     sector_t sector, end_sector, first_bad;
5511     int bad_sectors, dd_idx;
5512     struct md_io_acct *md_io_acct;
5513     bool did_inc;
5514
5515     if (!in_chunk_boundary(mddev, raid_bio)) {
5516         pr_debug("%s: non aligned\n", __func__);
5517         return 0;
5518     }
5519
5520     sector = raid5_compute_sector(conf, raid_bio->bi_iter.bi_sector, 0,
5521                       &dd_idx, NULL);
5522     end_sector = bio_end_sector(raid_bio);
5523
5524     rcu_read_lock();
5525     if (r5c_big_stripe_cached(conf, sector))
5526         goto out_rcu_unlock;
5527
5528     rdev = rcu_dereference(conf->disks[dd_idx].replacement);
5529     if (!rdev || test_bit(Faulty, &rdev->flags) ||
5530         rdev->recovery_offset < end_sector) {
5531         rdev = rcu_dereference(conf->disks[dd_idx].rdev);
5532         if (!rdev)
5533             goto out_rcu_unlock;
5534         if (test_bit(Faulty, &rdev->flags) ||
5535             !(test_bit(In_sync, &rdev->flags) ||
5536               rdev->recovery_offset >= end_sector))
5537             goto out_rcu_unlock;
5538     }
5539
5540     atomic_inc(&rdev->nr_pending);
5541     rcu_read_unlock();
5542
5543     if (is_badblock(rdev, sector, bio_sectors(raid_bio), &first_bad,
5544             &bad_sectors)) {
5545         bio_put(raid_bio);
5546         rdev_dec_pending(rdev, mddev);
5547         return 0;
5548     }
5549
5550     align_bio = bio_alloc_clone(rdev->bdev, raid_bio, GFP_NOIO,
5551                     &mddev->io_acct_set);
5552     md_io_acct = container_of(align_bio, struct md_io_acct, bio_clone);
5553     raid_bio->bi_next = (void *)rdev;
5554     if (blk_queue_io_stat(raid_bio->bi_bdev->bd_disk->queue))
5555         md_io_acct->start_time = bio_start_io_acct(raid_bio);
5556     md_io_acct->orig_bio = raid_bio;
5557
5558     align_bio->bi_end_io = raid5_align_endio;
5559     align_bio->bi_private = md_io_acct;
5560     align_bio->bi_iter.bi_sector = sector;
5561
5562     /* No reshape active, so we can trust rdev->data_offset */
5563     align_bio->bi_iter.bi_sector += rdev->data_offset;
5564
5565     did_inc = false;
5566     if (conf->quiesce == 0) {
5567         atomic_inc(&conf->active_aligned_reads);
5568         did_inc = true;
5569     }
5570     /* need a memory barrier to detect the race with raid5_quiesce() */
5571     if (!did_inc || smp_load_acquire(&conf->quiesce) != 0) {
5572         /* quiesce is in progress, so we need to undo io activation and wait
5573          * for it to finish
5574          */
5575         if (did_inc && atomic_dec_and_test(&conf->active_aligned_reads))
5576             wake_up(&conf->wait_for_quiescent);
5577         spin_lock_irq(&conf->device_lock);
5578         wait_event_lock_irq(conf->wait_for_quiescent, conf->quiesce == 0,
5579                     conf->device_lock);
5580         atomic_inc(&conf->active_aligned_reads);
5581         spin_unlock_irq(&conf->device_lock);
5582     }
5583
5584     if (mddev->gendisk)
5585         trace_block_bio_remap(align_bio, disk_devt(mddev->gendisk),
5586                       raid_bio->bi_iter.bi_sector);
5587     submit_bio_noacct(align_bio);
5588     return 1;
5589
5590 out_rcu_unlock:
5591     rcu_read_unlock();
5592     return 0;
5593 }
5594
5595 static struct bio *chunk_aligned_read(struct mddev *mddev, struct bio *raid_bio)
5596 {
5597     struct bio *split;
5598     sector_t sector = raid_bio->bi_iter.bi_sector;
5599     unsigned chunk_sects = mddev->chunk_sectors;
5600     unsigned sectors = chunk_sects - (sector & (chunk_sects-1));
5601
5602     if (sectors < bio_sectors(raid_bio)) {
5603         struct r5conf *conf = mddev->private;
5604         split = bio_split(raid_bio, sectors, GFP_NOIO, &conf->bio_split);
5605         bio_chain(split, raid_bio);
5606         submit_bio_noacct(raid_bio);
5607         raid_bio = split;
5608     }
5609
5610     if (!raid5_read_one_chunk(mddev, raid_bio))
5611         return raid_bio;
5612
5613     return NULL;
5614 }
5615
5616 /* __get_priority_stripe - get the next stripe to process
5617  *
5618  * Full stripe writes are allowed to pass preread active stripes up until
5619  * the bypass_threshold is exceeded.  In general the bypass_count
5620  * increments when the handle_list is handled before the hold_list; however, it
5621  * will not be incremented when STRIPE_IO_STARTED is sampled set signifying a
5622  * stripe with in flight i/o.  The bypass_count will be reset when the
5623  * head of the hold_list has changed, i.e. the head was promoted to the
5624  * handle_list.
5625  */
5626 static struct stripe_head *__get_priority_stripe(struct r5conf *conf, int group)
5627     __must_hold(&conf->device_lock)
5628 {
5629     struct stripe_head *sh, *tmp;
5630     struct list_head *handle_list = NULL;
5631     struct r5worker_group *wg;
5632     bool second_try = !r5c_is_writeback(conf->log) &&
5633         !r5l_log_disk_error(conf);
5634     bool try_loprio = test_bit(R5C_LOG_TIGHT, &conf->cache_state) ||
5635         r5l_log_disk_error(conf);
5636
5637 again:
5638     wg = NULL;
5639     sh = NULL;
5640     if (conf->worker_cnt_per_group == 0) {
5641         handle_list = try_loprio ? &conf->loprio_list :
5642                     &conf->handle_list;
5643     } else if (group != ANY_GROUP) {
5644         handle_list = try_loprio ? &conf->worker_groups[group].loprio_list :
5645                 &conf->worker_groups[group].handle_list;
5646         wg = &conf->worker_groups[group];
5647     } else {
5648         int i;
5649         for (i = 0; i < conf->group_cnt; i++) {
5650             handle_list = try_loprio ? &conf->worker_groups[i].loprio_list :
5651                 &conf->worker_groups[i].handle_list;
5652             wg = &conf->worker_groups[i];
5653             if (!list_empty(handle_list))
5654                 break;
5655         }
5656     }
5657
5658     pr_debug("%s: handle: %s hold: %s full_writes: %d bypass_count: %d\n",
5659           __func__,
5660           list_empty(handle_list) ? "empty" : "busy",
5661           list_empty(&conf->hold_list) ? "empty" : "busy",
5662           atomic_read(&conf->pending_full_writes), conf->bypass_count);
5663
5664     if (!list_empty(handle_list)) {
5665         sh = list_entry(handle_list->next, typeof(*sh), lru);
5666
5667         if (list_empty(&conf->hold_list))
5668             conf->bypass_count = 0;
5669         else if (!test_bit(STRIPE_IO_STARTED, &sh->state)) {
5670             if (conf->hold_list.next == conf->last_hold)
5671                 conf->bypass_count++;
5672             else {
5673                 conf->last_hold = conf->hold_list.next;
5674                 conf->bypass_count -= conf->bypass_threshold;
5675                 if (conf->bypass_count < 0)
5676                     conf->bypass_count = 0;
5677             }
5678         }
5679     } else if (!list_empty(&conf->hold_list) &&
5680            ((conf->bypass_threshold &&
5681              conf->bypass_count > conf->bypass_threshold) ||
5682             atomic_read(&conf->pending_full_writes) == 0)) {
5683
5684         list_for_each_entry(tmp, &conf->hold_list,  lru) {
5685             if (conf->worker_cnt_per_group == 0 ||
5686                 group == ANY_GROUP ||
5687                 !cpu_online(tmp->cpu) ||
5688                 cpu_to_group(tmp->cpu) == group) {
5689                 sh = tmp;
5690                 break;
5691             }
5692         }
5693
5694         if (sh) {
5695             conf->bypass_count -= conf->bypass_threshold;
5696             if (conf->bypass_count < 0)
5697                 conf->bypass_count = 0;
5698         }
5699         wg = NULL;
5700     }
5701
5702     if (!sh) {
5703         if (second_try)
5704             return NULL;
5705         second_try = true;
5706         try_loprio = !try_loprio;
5707         goto again;
5708     }
5709
5710     if (wg) {
5711         wg->stripes_cnt--;
5712         sh->group = NULL;
5713     }
5714     list_del_init(&sh->lru);
5715     BUG_ON(atomic_inc_return(&sh->count) != 1);
5716     return sh;
5717 }
5718
5719 struct raid5_plug_cb {
5720     struct blk_plug_cb  cb;
5721     struct list_head    list;
5722     struct list_head    temp_inactive_list[NR_STRIPE_HASH_LOCKS];
5723 };
5724
5725 static void raid5_unplug(struct blk_plug_cb *blk_cb, bool from_schedule)
5726 {
5727     struct raid5_plug_cb *cb = container_of(
5728         blk_cb, struct raid5_plug_cb, cb);
5729     struct stripe_head *sh;
5730     struct mddev *mddev = cb->cb.data;
5731     struct r5conf *conf = mddev->private;
5732     int cnt = 0;
5733     int hash;
5734
5735     if (cb->list.next && !list_empty(&cb->list)) {
5736         spin_lock_irq(&conf->device_lock);
5737         while (!list_empty(&cb->list)) {
5738             sh = list_first_entry(&cb->list, struct stripe_head, lru);
5739             list_del_init(&sh->lru);
5740             /*
5741              * avoid race release_stripe_plug() sees
5742              * STRIPE_ON_UNPLUG_LIST clear but the stripe
5743              * is still in our list
5744              */
5745             smp_mb__before_atomic();
5746             clear_bit(STRIPE_ON_UNPLUG_LIST, &sh->state);
5747             /*
5748              * STRIPE_ON_RELEASE_LIST could be set here. In that
5749              * case, the count is always > 1 here
5750              */
5751             hash = sh->hash_lock_index;
5752             __release_stripe(conf, sh, &cb->temp_inactive_list[hash]);
5753             cnt++;
5754         }
5755         spin_unlock_irq(&conf->device_lock);
5756     }
5757     release_inactive_stripe_list(conf, cb->temp_inactive_list,
5758                      NR_STRIPE_HASH_LOCKS);
5759     if (mddev->queue)
5760         trace_block_unplug(mddev->queue, cnt, !from_schedule);
5761     kfree(cb);
5762 }
5763
5764 static void release_stripe_plug(struct mddev *mddev,
5765                 struct stripe_head *sh)
5766 {
5767     struct blk_plug_cb *blk_cb = blk_check_plugged(
5768         raid5_unplug, mddev,
5769         sizeof(struct raid5_plug_cb));
5770     struct raid5_plug_cb *cb;
5771
5772     if (!blk_cb) {
5773         raid5_release_stripe(sh);
5774         return;
5775     }
5776
5777     cb = container_of(blk_cb, struct raid5_plug_cb, cb);
5778
5779     if (cb->list.next == NULL) {
5780         int i;
5781         INIT_LIST_HEAD(&cb->list);
5782         for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
5783             INIT_LIST_HEAD(cb->temp_inactive_list + i);
5784     }
5785
5786     if (!test_and_set_bit(STRIPE_ON_UNPLUG_LIST, &sh->state))
5787         list_add_tail(&sh->lru, &cb->list);
5788     else
5789         raid5_release_stripe(sh);
5790 }
5791
5792 static void make_discard_request(struct mddev *mddev, struct bio *bi)
5793 {
5794     struct r5conf *conf = mddev->private;
5795     sector_t logical_sector, last_sector;
5796     struct stripe_head *sh;
5797     int stripe_sectors;
5798
5799     /* We need to handle this when io_uring supports discard/trim */
5800     if (WARN_ON_ONCE(bi->bi_opf & REQ_NOWAIT))
5801         return;
5802
5803     if (mddev->reshape_position != MaxSector)
5804         /* Skip discard while reshape is happening */
5805         return;
5806
5807     logical_sector = bi->bi_iter.bi_sector & ~((sector_t)RAID5_STRIPE_SECTORS(conf)-1);
5808     last_sector = bio_end_sector(bi);
5809
5810     bi->bi_next = NULL;
5811
5812     stripe_sectors = conf->chunk_sectors *
5813         (conf->raid_disks - conf->max_degraded);
5814     logical_sector = DIV_ROUND_UP_SECTOR_T(logical_sector,
5815                            stripe_sectors);
5816     sector_div(last_sector, stripe_sectors);
5817
5818     logical_sector *= conf->chunk_sectors;
5819     last_sector *= conf->chunk_sectors;
5820
5821     for (; logical_sector < last_sector;
5822          logical_sector += RAID5_STRIPE_SECTORS(conf)) {
5823         DEFINE_WAIT(w);
5824         int d;
5825     again:
5826         sh = raid5_get_active_stripe(conf, logical_sector, 0, 0, 0);
5827         prepare_to_wait(&conf->wait_for_overlap, &w,
5828                 TASK_UNINTERRUPTIBLE);
5829         set_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags);
5830         if (test_bit(STRIPE_SYNCING, &sh->state)) {
5831             raid5_release_stripe(sh);
5832             schedule();
5833             goto again;
5834         }
5835         clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags);
5836         spin_lock_irq(&sh->stripe_lock);
5837         for (d = 0; d < conf->raid_disks; d++) {
5838             if (d == sh->pd_idx || d == sh->qd_idx)
5839                 continue;
5840             if (sh->dev[d].towrite || sh->dev[d].toread) {
5841                 set_bit(R5_Overlap, &sh->dev[d].flags);
5842                 spin_unlock_irq(&sh->stripe_lock);
5843                 raid5_release_stripe(sh);
5844                 schedule();
5845                 goto again;
5846             }
5847         }
5848         set_bit(STRIPE_DISCARD, &sh->state);
5849         finish_wait(&conf->wait_for_overlap, &w);
5850         sh->overwrite_disks = 0;
5851         for (d = 0; d < conf->raid_disks; d++) {
5852             if (d == sh->pd_idx || d == sh->qd_idx)
5853                 continue;
5854             sh->dev[d].towrite = bi;
5855             set_bit(R5_OVERWRITE, &sh->dev[d].flags);
5856             bio_inc_remaining(bi);
5857             md_write_inc(mddev, bi);
5858             sh->overwrite_disks++;
5859         }
5860         spin_unlock_irq(&sh->stripe_lock);
5861         if (conf->mddev->bitmap) {
5862             for (d = 0;
5863                  d < conf->raid_disks - conf->max_degraded;
5864                  d++)
5865                 md_bitmap_startwrite(mddev->bitmap,
5866                              sh->sector,
5867                              RAID5_STRIPE_SECTORS(conf),
5868                              0);
5869             sh->bm_seq = conf->seq_flush + 1;
5870             set_bit(STRIPE_BIT_DELAY, &sh->state);
5871         }
5872
5873         set_bit(STRIPE_HANDLE, &sh->state);
5874         clear_bit(STRIPE_DELAYED, &sh->state);
5875         if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
5876             atomic_inc(&conf->preread_active_stripes);
5877         release_stripe_plug(mddev, sh);
5878     }
5879
5880     bio_endio(bi);
5881 }
5882
5883 static bool ahead_of_reshape(struct mddev *mddev, sector_t sector,
5884                  sector_t reshape_sector)
5885 {
5886     return mddev->reshape_backwards ? sector < reshape_sector :
5887                       sector >= reshape_sector;
5888 }
5889
5890 static bool range_ahead_of_reshape(struct mddev *mddev, sector_t min,
5891                    sector_t max, sector_t reshape_sector)
5892 {
5893     return mddev->reshape_backwards ? max < reshape_sector :
5894                       min >= reshape_sector;
5895 }
5896
5897 static bool stripe_ahead_of_reshape(struct mddev *mddev, struct r5conf *conf,
5898                     struct stripe_head *sh)
5899 {
5900     sector_t max_sector = 0, min_sector = MaxSector;
5901     bool ret = false;
5902     int dd_idx;
5903
5904     for (dd_idx = 0; dd_idx < sh->disks; dd_idx++) {
5905         if (dd_idx == sh->pd_idx)
5906             continue;
5907
5908         min_sector = min(min_sector, sh->dev[dd_idx].sector);
5909         max_sector = min(max_sector, sh->dev[dd_idx].sector);
5910     }
5911
5912     spin_lock_irq(&conf->device_lock);
5913
5914     if (!range_ahead_of_reshape(mddev, min_sector, max_sector,
5915                      conf->reshape_progress))
5916         /* mismatch, need to try again */
5917         ret = true;
5918
5919     spin_unlock_irq(&conf->device_lock);
5920
5921     return ret;
5922 }
5923
5924 static int add_all_stripe_bios(struct r5conf *conf,
5925         struct stripe_request_ctx *ctx, struct stripe_head *sh,
5926         struct bio *bi, int forwrite, int previous)
5927 {
5928     int dd_idx;
5929     int ret = 1;
5930
5931     spin_lock_irq(&sh->stripe_lock);
5932
5933     for (dd_idx = 0; dd_idx < sh->disks; dd_idx++) {
5934         struct r5dev *dev = &sh->dev[dd_idx];
5935
5936         if (dd_idx == sh->pd_idx || dd_idx == sh->qd_idx)
5937             continue;
5938
5939         if (dev->sector < ctx->first_sector ||
5940             dev->sector >= ctx->last_sector)
5941             continue;
5942
5943         if (stripe_bio_overlaps(sh, bi, dd_idx, forwrite)) {
5944             set_bit(R5_Overlap, &dev->flags);
5945             ret = 0;
5946             continue;
5947         }
5948     }
5949
5950     if (!ret)
5951         goto out;
5952
5953     for (dd_idx = 0; dd_idx < sh->disks; dd_idx++) {
5954         struct r5dev *dev = &sh->dev[dd_idx];
5955
5956         if (dd_idx == sh->pd_idx || dd_idx == sh->qd_idx)
5957             continue;
5958
5959         if (dev->sector < ctx->first_sector ||
5960             dev->sector >= ctx->last_sector)
5961             continue;
5962
5963         __add_stripe_bio(sh, bi, dd_idx, forwrite, previous);
5964         clear_bit((dev->sector - ctx->first_sector) >>
5965               RAID5_STRIPE_SHIFT(conf), ctx->sectors_to_do);
5966     }
5967
5968 out:
5969     spin_unlock_irq(&sh->stripe_lock);
5970     return ret;
5971 }
5972
5973 static enum stripe_result make_stripe_request(struct mddev *mddev,
5974         struct r5conf *conf, struct stripe_request_ctx *ctx,
5975         sector_t logical_sector, struct bio *bi)
5976 {
5977     const int rw = bio_data_dir(bi);
5978     enum stripe_result ret;
5979     struct stripe_head *sh;
5980     sector_t new_sector;
5981     int previous = 0;
5982     int seq, dd_idx;
5983
5984     seq = read_seqcount_begin(&conf->gen_lock);
5985
5986     if (unlikely(conf->reshape_progress != MaxSector)) {
5987         /*
5988          * Spinlock is needed as reshape_progress may be
5989          * 64bit on a 32bit platform, and so it might be
5990          * possible to see a half-updated value
5991          * Of course reshape_progress could change after
5992          * the lock is dropped, so once we get a reference
5993          * to the stripe that we think it is, we will have
5994          * to check again.
5995          */
5996         spin_lock_irq(&conf->device_lock);
5997         if (ahead_of_reshape(mddev, logical_sector,
5998                      conf->reshape_progress)) {
5999             previous = 1;
6000         } else {
6001             if (ahead_of_reshape(mddev, logical_sector,
6002                          conf->reshape_safe)) {
6003                 spin_unlock_irq(&conf->device_lock);
6004                 return STRIPE_SCHEDULE_AND_RETRY;
6005             }
6006         }
6007         spin_unlock_irq(&conf->device_lock);
6008     }
6009
6010     new_sector = raid5_compute_sector(conf, logical_sector, previous,
6011                       &dd_idx, NULL);
6012     pr_debug("raid456: %s, sector %llu logical %llu\n", __func__,
6013          new_sector, logical_sector);
6014
6015     sh = __raid5_get_active_stripe(conf, ctx, new_sector, previous,
6016                        (bi->bi_opf & REQ_RAHEAD), 0);
6017     if (unlikely(!sh)) {
6018         /* cannot get stripe, just give-up */
6019         bi->bi_status = BLK_STS_IOERR;
6020         return STRIPE_FAIL;
6021     }
6022
6023     if (unlikely(previous) &&
6024         stripe_ahead_of_reshape(mddev, conf, sh)) {
6025         /*
6026          * Expansion moved on while waiting for a stripe.
6027          * Expansion could still move past after this
6028          * test, but as we are holding a reference to
6029          * 'sh', we know that if that happens,
6030          *  STRIPE_EXPANDING will get set and the expansion
6031          * won't proceed until we finish with the stripe.
6032          */
6033         ret = STRIPE_SCHEDULE_AND_RETRY;
6034         goto out_release;
6035     }
6036
6037     if (read_seqcount_retry(&conf->gen_lock, seq)) {
6038         /* Might have got the wrong stripe_head by accident */
6039         ret = STRIPE_RETRY;
6040         goto out_release;
6041     }
6042
6043     if (test_bit(STRIPE_EXPANDING, &sh->state) ||
6044         !add_all_stripe_bios(conf, ctx, sh, bi, rw, previous)) {
6045         /*
6046          * Stripe is busy expanding or add failed due to
6047          * overlap. Flush everything and wait a while.
6048          */
6049         md_wakeup_thread(mddev->thread);
6050         ret = STRIPE_SCHEDULE_AND_RETRY;
6051         goto out_release;
6052     }
6053
6054     if (stripe_can_batch(sh)) {
6055         stripe_add_to_batch_list(conf, sh, ctx->batch_last);
6056         if (ctx->batch_last)
6057             raid5_release_stripe(ctx->batch_last);
6058         atomic_inc(&sh->count);
6059         ctx->batch_last = sh;
6060     }
6061
6062     if (ctx->do_flush) {
6063         set_bit(STRIPE_R5C_PREFLUSH, &sh->state);
6064         /* we only need flush for one stripe */
6065         ctx->do_flush = false;
6066     }
6067
6068     set_bit(STRIPE_HANDLE, &sh->state);
6069     clear_bit(STRIPE_DELAYED, &sh->state);
6070     if ((!sh->batch_head || sh == sh->batch_head) &&
6071         (bi->bi_opf & REQ_SYNC) &&
6072         !test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
6073         atomic_inc(&conf->preread_active_stripes);
6074
6075     release_stripe_plug(mddev, sh);
6076     return STRIPE_SUCCESS;
6077
6078 out_release:
6079     raid5_release_stripe(sh);
6080     return ret;
6081 }
6082
6083 static bool raid5_make_request(struct mddev *mddev, struct bio * bi)
6084 {
6085     DEFINE_WAIT_FUNC(wait, woken_wake_function);
6086     struct r5conf *conf = mddev->private;
6087     sector_t logical_sector;
6088     struct stripe_request_ctx ctx = {};
6089     const int rw = bio_data_dir(bi);
6090     enum stripe_result res;
6091     int s, stripe_cnt;
6092
6093     if (unlikely(bi->bi_opf & REQ_PREFLUSH)) {
6094         int ret = log_handle_flush_request(conf, bi);
6095
6096         if (ret == 0)
6097             return true;
6098         if (ret == -ENODEV) {
6099             if (md_flush_request(mddev, bi))
6100                 return true;
6101         }
6102         /* ret == -EAGAIN, fallback */
6103         /*
6104          * if r5l_handle_flush_request() didn't clear REQ_PREFLUSH,
6105          * we need to flush journal device
6106          */
6107         ctx.do_flush = bi->bi_opf & REQ_PREFLUSH;
6108     }
6109
6110     if (!md_write_start(mddev, bi))
6111         return false;
6112     /*
6113      * If array is degraded, better not do chunk aligned read because
6114      * later we might have to read it again in order to reconstruct
6115      * data on failed drives.
6116      */
6117     if (rw == READ && mddev->degraded == 0 &&
6118         mddev->reshape_position == MaxSector) {
6119         bi = chunk_aligned_read(mddev, bi);
6120         if (!bi)
6121             return true;
6122     }
6123
6124     if (unlikely(bio_op(bi) == REQ_OP_DISCARD)) {
6125         make_discard_request(mddev, bi);
6126         md_write_end(mddev);
6127         return true;
6128     }
6129
6130     logical_sector = bi->bi_iter.bi_sector & ~((sector_t)RAID5_STRIPE_SECTORS(conf)-1);
6131     ctx.first_sector = logical_sector;
6132     ctx.last_sector = bio_end_sector(bi);
6133     bi->bi_next = NULL;
6134
6135     stripe_cnt = DIV_ROUND_UP_SECTOR_T(ctx.last_sector - logical_sector,
6136                        RAID5_STRIPE_SECTORS(conf));
6137     bitmap_set(ctx.sectors_to_do, 0, stripe_cnt);
6138
6139     pr_debug("raid456: %s, logical %llu to %llu\n", __func__,
6140          bi->bi_iter.bi_sector, ctx.last_sector);
6141
6142     /* Bail out if conflicts with reshape and REQ_NOWAIT is set */
6143     if ((bi->bi_opf & REQ_NOWAIT) &&
6144         (conf->reshape_progress != MaxSector) &&
6145         !ahead_of_reshape(mddev, logical_sector, conf->reshape_progress) &&
6146         ahead_of_reshape(mddev, logical_sector, conf->reshape_safe)) {
6147         bio_wouldblock_error(bi);
6148         if (rw == WRITE)
6149             md_write_end(mddev);
6150         return true;
6151     }
6152     md_account_bio(mddev, &bi);
6153
6154     add_wait_queue(&conf->wait_for_overlap, &wait);
6155     while (1) {
6156         res = make_stripe_request(mddev, conf, &ctx, logical_sector,
6157                       bi);
6158         if (res == STRIPE_FAIL)
6159             break;
6160
6161         if (res == STRIPE_RETRY)
6162             continue;
6163
6164         if (res == STRIPE_SCHEDULE_AND_RETRY) {
6165             /*
6166              * Must release the reference to batch_last before
6167              * scheduling and waiting for work to be done,
6168              * otherwise the batch_last stripe head could prevent
6169              * raid5_activate_delayed() from making progress
6170              * and thus deadlocking.
6171              */
6172             if (ctx.batch_last) {
6173                 raid5_release_stripe(ctx.batch_last);
6174                 ctx.batch_last = NULL;
6175             }
6176
6177             wait_woken(&wait, TASK_UNINTERRUPTIBLE,
6178                    MAX_SCHEDULE_TIMEOUT);
6179             continue;
6180         }
6181
6182         s = find_first_bit(ctx.sectors_to_do, stripe_cnt);
6183         if (s == stripe_cnt)
6184             break;
6185
6186         logical_sector = ctx.first_sector +
6187             (s << RAID5_STRIPE_SHIFT(conf));
6188     }
6189     remove_wait_queue(&conf->wait_for_overlap, &wait);
6190
6191     if (ctx.batch_last)
6192         raid5_release_stripe(ctx.batch_last);
6193
6194     if (rw == WRITE)
6195         md_write_end(mddev);
6196     bio_endio(bi);
6197     return true;
6198 }
6199
6200 static sector_t raid5_size(struct mddev *mddev, sector_t sectors, int raid_disks);
6201
6202 static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr, int *skipped)
6203 {
6204     /* reshaping is quite different to recovery/resync so it is
6205      * handled quite separately ... here.
6206      *
6207      * On each call to sync_request, we gather one chunk worth of
6208      * destination stripes and flag them as expanding.
6209      * Then we find all the source stripes and request reads.
6210      * As the reads complete, handle_stripe will copy the data
6211      * into the destination stripe and release that stripe.
6212      */
6213     struct r5conf *conf = mddev->private;
6214     struct stripe_head *sh;
6215     struct md_rdev *rdev;
6216     sector_t first_sector, last_sector;
6217     int raid_disks = conf->previous_raid_disks;
6218     int data_disks = raid_disks - conf->max_degraded;
6219     int new_data_disks = conf->raid_disks - conf->max_degraded;
6220     int i;
6221     int dd_idx;
6222     sector_t writepos, readpos, safepos;
6223     sector_t stripe_addr;
6224     int reshape_sectors;
6225     struct list_head stripes;
6226     sector_t retn;
6227
6228     if (sector_nr == 0) {
6229         /* If restarting in the middle, skip the initial sectors */
6230         if (mddev->reshape_backwards &&
6231             conf->reshape_progress < raid5_size(mddev, 0, 0)) {
6232             sector_nr = raid5_size(mddev, 0, 0)
6233                 - conf->reshape_progress;
6234         } else if (mddev->reshape_backwards &&
6235                conf->reshape_progress == MaxSector) {
6236             /* shouldn't happen, but just in case, finish up.*/
6237             sector_nr = MaxSector;
6238         } else if (!mddev->reshape_backwards &&
6239                conf->reshape_progress > 0)
6240             sector_nr = conf->reshape_progress;
6241         sector_div(sector_nr, new_data_disks);
6242         if (sector_nr) {
6243             mddev->curr_resync_completed = sector_nr;
6244             sysfs_notify_dirent_safe(mddev->sysfs_completed);
6245             *skipped = 1;
6246             retn = sector_nr;
6247             goto finish;
6248         }
6249     }
6250
6251     /* We need to process a full chunk at a time.
6252      * If old and new chunk sizes differ, we need to process the
6253      * largest of these
6254      */
6255
6256     reshape_sectors = max(conf->chunk_sectors, conf->prev_chunk_sectors);
6257
6258     /* We update the metadata at least every 10 seconds, or when
6259      * the data about to be copied would over-write the source of
6260      * the data at the front of the range.  i.e. one new_stripe
6261      * along from reshape_progress new_maps to after where
6262      * reshape_safe old_maps to
6263      */
6264     writepos = conf->reshape_progress;
6265     sector_div(writepos, new_data_disks);
6266     readpos = conf->reshape_progress;
6267     sector_div(readpos, data_disks);
6268     safepos = conf->reshape_safe;
6269     sector_div(safepos, data_disks);
6270     if (mddev->reshape_backwards) {
6271         BUG_ON(writepos < reshape_sectors);
6272         writepos -= reshape_sectors;
6273         readpos += reshape_sectors;
6274         safepos += reshape_sectors;
6275     } else {
6276         writepos += reshape_sectors;
6277         /* readpos and safepos are worst-case calculations.
6278          * A negative number is overly pessimistic, and causes
6279          * obvious problems for unsigned storage.  So clip to 0.
6280          */
6281         readpos -= min_t(sector_t, reshape_sectors, readpos);
6282         safepos -= min_t(sector_t, reshape_sectors, safepos);
6283     }
6284
6285     /* Having calculated the 'writepos' possibly use it
6286      * to set 'stripe_addr' which is where we will write to.
6287      */
6288     if (mddev->reshape_backwards) {
6289         BUG_ON(conf->reshape_progress == 0);
6290         stripe_addr = writepos;
6291         BUG_ON((mddev->dev_sectors &
6292             ~((sector_t)reshape_sectors - 1))
6293                - reshape_sectors - stripe_addr
6294                != sector_nr);
6295     } else {
6296         BUG_ON(writepos != sector_nr + reshape_sectors);
6297         stripe_addr = sector_nr;
6298     }
6299
6300     /* 'writepos' is the most advanced device address we might write.
6301      * 'readpos' is the least advanced device address we might read.
6302      * 'safepos' is the least address recorded in the metadata as having
6303      *     been reshaped.
6304      * If there is a min_offset_diff, these are adjusted either by
6305      * increasing the safepos/readpos if diff is negative, or
6306      * increasing writepos if diff is positive.
6307      * If 'readpos' is then behind 'writepos', there is no way that we can
6308      * ensure safety in the face of a crash - that must be done by userspace
6309      * making a backup of the data.  So in that case there is no particular
6310      * rush to update metadata.
6311      * Otherwise if 'safepos' is behind 'writepos', then we really need to
6312      * update the metadata to advance 'safepos' to match 'readpos' so that
6313      * we can be safe in the event of a crash.
6314      * So we insist on updating metadata if safepos is behind writepos and
6315      * readpos is beyond writepos.
6316      * In any case, update the metadata every 10 seconds.
6317      * Maybe that number should be configurable, but I'm not sure it is
6318      * worth it.... maybe it could be a multiple of safemode_delay???
6319      */
6320     if (conf->min_offset_diff < 0) {
6321         safepos += -conf->min_offset_diff;
6322         readpos += -conf->min_offset_diff;
6323     } else
6324         writepos += conf->min_offset_diff;
6325
6326     if ((mddev->reshape_backwards
6327          ? (safepos > writepos && readpos < writepos)
6328          : (safepos < writepos && readpos > writepos)) ||
6329         time_after(jiffies, conf->reshape_checkpoint + 10*HZ)) {
6330         /* Cannot proceed until we've updated the superblock... */
6331         wait_event(conf->wait_for_overlap,
6332                atomic_read(&conf->reshape_stripes)==0
6333                || test_bit(MD_RECOVERY_INTR, &mddev->recovery));
6334         if (atomic_read(&conf->reshape_stripes) != 0)
6335             return 0;
6336         mddev->reshape_position = conf->reshape_progress;
6337         mddev->curr_resync_completed = sector_nr;
6338         if (!mddev->reshape_backwards)
6339             /* Can update recovery_offset */
6340             rdev_for_each(rdev, mddev)
6341                 if (rdev->raid_disk >= 0 &&
6342                     !test_bit(Journal, &rdev->flags) &&
6343                     !test_bit(In_sync, &rdev->flags) &&
6344                     rdev->recovery_offset < sector_nr)
6345                     rdev->recovery_offset = sector_nr;
6346
6347         conf->reshape_checkpoint = jiffies;
6348         set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
6349         md_wakeup_thread(mddev->thread);
6350         wait_event(mddev->sb_wait, mddev->sb_flags == 0 ||
6351                test_bit(MD_RECOVERY_INTR, &mddev->recovery));
6352         if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
6353             return 0;
6354         spin_lock_irq(&conf->device_lock);
6355         conf->reshape_safe = mddev->reshape_position;
6356         spin_unlock_irq(&conf->device_lock);
6357         wake_up(&conf->wait_for_overlap);
6358         sysfs_notify_dirent_safe(mddev->sysfs_completed);
6359     }
6360
6361     INIT_LIST_HEAD(&stripes);
6362     for (i = 0; i < reshape_sectors; i += RAID5_STRIPE_SECTORS(conf)) {
6363         int j;
6364         int skipped_disk = 0;
6365         sh = raid5_get_active_stripe(conf, stripe_addr+i, 0, 0, 1);
6366         set_bit(STRIPE_EXPANDING, &sh->state);
6367         atomic_inc(&conf->reshape_stripes);
6368         /* If any of this stripe is beyond the end of the old
6369          * array, then we need to zero those blocks
6370          */
6371         for (j=sh->disks; j--;) {
6372             sector_t s;
6373             if (j == sh->pd_idx)
6374                 continue;
6375             if (conf->level == 6 &&
6376                 j == sh->qd_idx)
6377                 continue;
6378             s = raid5_compute_blocknr(sh, j, 0);
6379             if (s < raid5_size(mddev, 0, 0)) {
6380                 skipped_disk = 1;
6381                 continue;
6382             }
6383             memset(page_address(sh->dev[j].page), 0, RAID5_STRIPE_SIZE(conf));
6384             set_bit(R5_Expanded, &sh->dev[j].flags);
6385             set_bit(R5_UPTODATE, &sh->dev[j].flags);
6386         }
6387         if (!skipped_disk) {
6388             set_bit(STRIPE_EXPAND_READY, &sh->state);
6389             set_bit(STRIPE_HANDLE, &sh->state);
6390         }
6391         list_add(&sh->lru, &stripes);
6392     }
6393     spin_lock_irq(&conf->device_lock);
6394     if (mddev->reshape_backwards)
6395         conf->reshape_progress -= reshape_sectors * new_data_disks;
6396     else
6397         conf->reshape_progress += reshape_sectors * new_data_disks;
6398     spin_unlock_irq(&conf->device_lock);
6399     /* Ok, those stripe are ready. We can start scheduling
6400      * reads on the source stripes.
6401      * The source stripes are determined by mapping the first and last
6402      * block on the destination stripes.
6403      */
6404     first_sector =
6405         raid5_compute_sector(conf, stripe_addr*(new_data_disks),
6406                      1, &dd_idx, NULL);
6407     last_sector =
6408         raid5_compute_sector(conf, ((stripe_addr+reshape_sectors)
6409                         * new_data_disks - 1),
6410                      1, &dd_idx, NULL);
6411     if (last_sector >= mddev->dev_sectors)
6412         last_sector = mddev->dev_sectors - 1;
6413     while (first_sector <= last_sector) {
6414         sh = raid5_get_active_stripe(conf, first_sector, 1, 0, 1);
6415         set_bit(STRIPE_EXPAND_SOURCE, &sh->state);
6416         set_bit(STRIPE_HANDLE, &sh->state);
6417         raid5_release_stripe(sh);
6418         first_sector += RAID5_STRIPE_SECTORS(conf);
6419     }
6420     /* Now that the sources are clearly marked, we can release
6421      * the destination stripes
6422      */
6423     while (!list_empty(&stripes)) {
6424         sh = list_entry(stripes.next, struct stripe_head, lru);
6425         list_del_init(&sh->lru);
6426         raid5_release_stripe(sh);
6427     }
6428     /* If this takes us to the resync_max point where we have to pause,
6429      * then we need to write out the superblock.
6430      */
6431     sector_nr += reshape_sectors;
6432     retn = reshape_sectors;
6433 finish:
6434     if (mddev->curr_resync_completed > mddev->resync_max ||
6435         (sector_nr - mddev->curr_resync_completed) * 2
6436         >= mddev->resync_max - mddev->curr_resync_completed) {
6437         /* Cannot proceed until we've updated the superblock... */
6438         wait_event(conf->wait_for_overlap,
6439                atomic_read(&conf->reshape_stripes) == 0
6440                || test_bit(MD_RECOVERY_INTR, &mddev->recovery));
6441         if (atomic_read(&conf->reshape_stripes) != 0)
6442             goto ret;
6443         mddev->reshape_position = conf->reshape_progress;
6444         mddev->curr_resync_completed = sector_nr;
6445         if (!mddev->reshape_backwards)
6446             /* Can update recovery_offset */
6447             rdev_for_each(rdev, mddev)
6448                 if (rdev->raid_disk >= 0 &&
6449                     !test_bit(Journal, &rdev->flags) &&
6450                     !test_bit(In_sync, &rdev->flags) &&
6451                     rdev->recovery_offset < sector_nr)
6452                     rdev->recovery_offset = sector_nr;
6453         conf->reshape_checkpoint = jiffies;
6454         set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
6455         md_wakeup_thread(mddev->thread);
6456         wait_event(mddev->sb_wait,
6457                !test_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags)
6458                || test_bit(MD_RECOVERY_INTR, &mddev->recovery));
6459         if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
6460             goto ret;
6461         spin_lock_irq(&conf->device_lock);
6462         conf->reshape_safe = mddev->reshape_position;
6463         spin_unlock_irq(&conf->device_lock);
6464         wake_up(&conf->wait_for_overlap);
6465         sysfs_notify_dirent_safe(mddev->sysfs_completed);
6466     }
6467 ret:
6468     return retn;
6469 }
6470
6471 static inline sector_t raid5_sync_request(struct mddev *mddev, sector_t sector_nr,
6472                       int *skipped)
6473 {
6474     struct r5conf *conf = mddev->private;
6475     struct stripe_head *sh;
6476     sector_t max_sector = mddev->dev_sectors;
6477     sector_t sync_blocks;
6478     int still_degraded = 0;
6479     int i;
6480
6481     if (sector_nr >= max_sector) {
6482         /* just being told to finish up .. nothing much to do */
6483
6484         if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) {
6485             end_reshape(conf);
6486             return 0;
6487         }
6488
6489         if (mddev->curr_resync < max_sector) /* aborted */
6490             md_bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
6491                        &sync_blocks, 1);
6492         else /* completed sync */
6493             conf->fullsync = 0;
6494         md_bitmap_close_sync(mddev->bitmap);
6495
6496         return 0;
6497     }
6498
6499     /* Allow raid5_quiesce to complete */
6500     wait_event(conf->wait_for_overlap, conf->quiesce != 2);
6501
6502     if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
6503         return reshape_request(mddev, sector_nr, skipped);
6504
6505     /* No need to check resync_max as we never do more than one
6506      * stripe, and as resync_max will always be on a chunk boundary,
6507      * if the check in md_do_sync didn't fire, there is no chance
6508      * of overstepping resync_max here
6509      */
6510
6511     /* if there is too many failed drives and we are trying
6512      * to resync, then assert that we are finished, because there is
6513      * nothing we can do.
6514      */
6515     if (mddev->degraded >= conf->max_degraded &&
6516         test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
6517         sector_t rv = mddev->dev_sectors - sector_nr;
6518         *skipped = 1;
6519         return rv;
6520     }
6521     if (!test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
6522         !conf->fullsync &&
6523         !md_bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
6524         sync_blocks >= RAID5_STRIPE_SECTORS(conf)) {
6525         /* we can skip this block, and probably more */
6526         do_div(sync_blocks, RAID5_STRIPE_SECTORS(conf));
6527         *skipped = 1;
6528         /* keep things rounded to whole stripes */
6529         return sync_blocks * RAID5_STRIPE_SECTORS(conf);
6530     }
6531
6532     md_bitmap_cond_end_sync(mddev->bitmap, sector_nr, false);
6533
6534     sh = raid5_get_active_stripe(conf, sector_nr, 0, 1, 0);
6535     if (sh == NULL) {
6536         sh = raid5_get_active_stripe(conf, sector_nr, 0, 0, 0);
6537         /* make sure we don't swamp the stripe cache if someone else
6538          * is trying to get access
6539          */
6540         schedule_timeout_uninterruptible(1);
6541     }
6542     /* Need to check if array will still be degraded after recovery/resync
6543      * Note in case of > 1 drive failures it's possible we're rebuilding
6544      * one drive while leaving another faulty drive in array.
6545      */
6546     rcu_read_lock();
6547     for (i = 0; i < conf->raid_disks; i++) {
6548         struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
6549
6550         if (rdev == NULL || test_bit(Faulty, &rdev->flags))
6551             still_degraded = 1;
6552     }
6553     rcu_read_unlock();
6554
6555     md_bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, still_degraded);
6556
6557     set_bit(STRIPE_SYNC_REQUESTED, &sh->state);
6558     set_bit(STRIPE_HANDLE, &sh->state);
6559
6560     raid5_release_stripe(sh);
6561
6562     return RAID5_STRIPE_SECTORS(conf);
6563 }
6564
6565 static int  retry_aligned_read(struct r5conf *conf, struct bio *raid_bio,
6566                    unsigned int offset)
6567 {
6568     /* We may not be able to submit a whole bio at once as there
6569      * may not be enough stripe_heads available.
6570      * We cannot pre-allocate enough stripe_heads as we may need
6571      * more than exist in the cache (if we allow ever large chunks).
6572      * So we do one stripe head at a time and record in
6573      * ->bi_hw_segments how many have been done.
6574      *
6575      * We *know* that this entire raid_bio is in one chunk, so
6576      * it will be only one 'dd_idx' and only need one call to raid5_compute_sector.
6577      */
6578     struct stripe_head *sh;
6579     int dd_idx;
6580     sector_t sector, logical_sector, last_sector;
6581     int scnt = 0;
6582     int handled = 0;
6583
6584     logical_sector = raid_bio->bi_iter.bi_sector &
6585         ~((sector_t)RAID5_STRIPE_SECTORS(conf)-1);
6586     sector = raid5_compute_sector(conf, logical_sector,
6587                       0, &dd_idx, NULL);
6588     last_sector = bio_end_sector(raid_bio);
6589
6590     for (; logical_sector < last_sector;
6591          logical_sector += RAID5_STRIPE_SECTORS(conf),
6592              sector += RAID5_STRIPE_SECTORS(conf),
6593              scnt++) {
6594
6595         if (scnt < offset)
6596             /* already done this stripe */
6597             continue;
6598
6599         sh = raid5_get_active_stripe(conf, sector, 0, 1, 1);
6600
6601         if (!sh) {
6602             /* failed to get a stripe - must wait */
6603             conf->retry_read_aligned = raid_bio;
6604             conf->retry_read_offset = scnt;
6605             return handled;
6606         }
6607
6608         if (!add_stripe_bio(sh, raid_bio, dd_idx, 0, 0)) {
6609             raid5_release_stripe(sh);
6610             conf->retry_read_aligned = raid_bio;
6611             conf->retry_read_offset = scnt;
6612             return handled;
6613         }
6614
6615         set_bit(R5_ReadNoMerge, &sh->dev[dd_idx].flags);
6616         handle_stripe(sh);
6617         raid5_release_stripe(sh);
6618         handled++;
6619     }
6620
6621     bio_endio(raid_bio);
6622
6623     if (atomic_dec_and_test(&conf->active_aligned_reads))
6624         wake_up(&conf->wait_for_quiescent);
6625     return handled;
6626 }
6627
6628 static int handle_active_stripes(struct r5conf *conf, int group,
6629                  struct r5worker *worker,
6630                  struct list_head *temp_inactive_list)
6631         __must_hold(&conf->device_lock)
6632 {
6633     struct stripe_head *batch[MAX_STRIPE_BATCH], *sh;
6634     int i, batch_size = 0, hash;
6635     bool release_inactive = false;
6636
6637     while (batch_size < MAX_STRIPE_BATCH &&
6638             (sh = __get_priority_stripe(conf, group)) != NULL)
6639         batch[batch_size++] = sh;
6640
6641     if (batch_size == 0) {
6642         for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
6643             if (!list_empty(temp_inactive_list + i))
6644                 break;
6645         if (i == NR_STRIPE_HASH_LOCKS) {
6646             spin_unlock_irq(&conf->device_lock);
6647             log_flush_stripe_to_raid(conf);
6648             spin_lock_irq(&conf->device_lock);
6649             return batch_size;
6650         }
6651         release_inactive = true;
6652     }
6653     spin_unlock_irq(&conf->device_lock);
6654
6655     release_inactive_stripe_list(conf, temp_inactive_list,
6656                      NR_STRIPE_HASH_LOCKS);
6657
6658     r5l_flush_stripe_to_raid(conf->log);
6659     if (release_inactive) {
6660         spin_lock_irq(&conf->device_lock);
6661         return 0;
6662     }
6663
6664     for (i = 0; i < batch_size; i++)
6665         handle_stripe(batch[i]);
6666     log_write_stripe_run(conf);
6667
6668     cond_resched();
6669
6670     spin_lock_irq(&conf->device_lock);
6671     for (i = 0; i < batch_size; i++) {
6672         hash = batch[i]->hash_lock_index;
6673         __release_stripe(conf, batch[i], &temp_inactive_list[hash]);
6674     }
6675     return batch_size;
6676 }
6677
6678 static void raid5_do_work(struct work_struct *work)
6679 {
6680     struct r5worker *worker = container_of(work, struct r5worker, work);
6681     struct r5worker_group *group = worker->group;
6682     struct r5conf *conf = group->conf;
6683     struct mddev *mddev = conf->mddev;
6684     int group_id = group - conf->worker_groups;
6685     int handled;
6686     struct blk_plug plug;
6687
6688     pr_debug("+++ raid5worker active\n");
6689
6690     blk_start_plug(&plug);
6691     handled = 0;
6692     spin_lock_irq(&conf->device_lock);
6693     while (1) {
6694         int batch_size, released;
6695
6696         released = release_stripe_list(conf, worker->temp_inactive_list);
6697
6698         batch_size = handle_active_stripes(conf, group_id, worker,
6699                            worker->temp_inactive_list);
6700         worker->working = false;
6701         if (!batch_size && !released)
6702             break;
6703         handled += batch_size;
6704         wait_event_lock_irq(mddev->sb_wait,
6705             !test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags),
6706             conf->device_lock);
6707     }
6708     pr_debug("%d stripes handled\n", handled);
6709
6710     spin_unlock_irq(&conf->device_lock);
6711
6712     flush_deferred_bios(conf);
6713
6714     r5l_flush_stripe_to_raid(conf->log);
6715
6716     async_tx_issue_pending_all();
6717     blk_finish_plug(&plug);
6718
6719     pr_debug("--- raid5worker inactive\n");
6720 }
6721
6722 /*
6723  * This is our raid5 kernel thread.
6724  *
6725  * We scan the hash table for stripes which can be handled now.
6726  * During the scan, completed stripes are saved for us by the interrupt
6727  * handler, so that they will not have to wait for our next wakeup.
6728  */
6729 static void raid5d(struct md_thread *thread)
6730 {
6731     struct mddev *mddev = thread->mddev;
6732     struct r5conf *conf = mddev->private;
6733     int handled;
6734     struct blk_plug plug;
6735
6736     pr_debug("+++ raid5d active\n");
6737
6738     md_check_recovery(mddev);
6739
6740     blk_start_plug(&plug);
6741     handled = 0;
6742     spin_lock_irq(&conf->device_lock);
6743     while (1) {
6744         struct bio *bio;
6745         int batch_size, released;
6746         unsigned int offset;
6747
6748         released = release_stripe_list(conf, conf->temp_inactive_list);
6749         if (released)
6750             clear_bit(R5_DID_ALLOC, &conf->cache_state);
6751
6752         if (
6753             !list_empty(&conf->bitmap_list)) {
6754             /* Now is a good time to flush some bitmap updates */
6755             conf->seq_flush++;
6756             spin_unlock_irq(&conf->device_lock);
6757             md_bitmap_unplug(mddev->bitmap);
6758             spin_lock_irq(&conf->device_lock);
6759             conf->seq_write = conf->seq_flush;
6760             activate_bit_delay(conf, conf->temp_inactive_list);
6761         }
6762         raid5_activate_delayed(conf);
6763
6764         while ((bio = remove_bio_from_retry(conf, &offset))) {
6765             int ok;
6766             spin_unlock_irq(&conf->device_lock);
6767             ok = retry_aligned_read(conf, bio, offset);
6768             spin_lock_irq(&conf->device_lock);
6769             if (!ok)
6770                 break;
6771             handled++;
6772         }
6773
6774         batch_size = handle_active_stripes(conf, ANY_GROUP, NULL,
6775                            conf->temp_inactive_list);
6776         if (!batch_size && !released)
6777             break;
6778         handled += batch_size;
6779
6780         if (mddev->sb_flags & ~(1 << MD_SB_CHANGE_PENDING)) {
6781             spin_unlock_irq(&conf->device_lock);
6782             md_check_recovery(mddev);
6783             spin_lock_irq(&conf->device_lock);
6784         }
6785     }
6786     pr_debug("%d stripes handled\n", handled);
6787
6788     spin_unlock_irq(&conf->device_lock);
6789     if (test_and_clear_bit(R5_ALLOC_MORE, &conf->cache_state) &&
6790         mutex_trylock(&conf->cache_size_mutex)) {
6791         grow_one_stripe(conf, __GFP_NOWARN);
6792         /* Set flag even if allocation failed.  This helps
6793          * slow down allocation requests when mem is short
6794          */
6795         set_bit(R5_DID_ALLOC, &conf->cache_state);
6796         mutex_unlock(&conf->cache_size_mutex);
6797     }
6798
6799     flush_deferred_bios(conf);
6800
6801     r5l_flush_stripe_to_raid(conf->log);
6802
6803     async_tx_issue_pending_all();
6804     blk_finish_plug(&plug);
6805
6806     pr_debug("--- raid5d inactive\n");
6807 }
6808
6809 static ssize_t
6810 raid5_show_stripe_cache_size(struct mddev *mddev, char *page)
6811 {
6812     struct r5conf *conf;
6813     int ret = 0;
6814     spin_lock(&mddev->lock);
6815     conf = mddev->private;
6816     if (conf)
6817         ret = sprintf(page, "%d\n", conf->min_nr_stripes);
6818     spin_unlock(&mddev->lock);
6819     return ret;
6820 }
6821
6822 int
6823 raid5_set_cache_size(struct mddev *mddev, int size)
6824 {
6825     int result = 0;
6826     struct r5conf *conf = mddev->private;
6827
6828     if (size <= 16 || size > 32768)
6829         return -EINVAL;
6830
6831     conf->min_nr_stripes = size;
6832     mutex_lock(&conf->cache_size_mutex);
6833     while (size < conf->max_nr_stripes &&
6834            drop_one_stripe(conf))
6835         ;
6836     mutex_unlock(&conf->cache_size_mutex);
6837
6838     md_allow_write(mddev);
6839
6840     mutex_lock(&conf->cache_size_mutex);
6841     while (size > conf->max_nr_stripes)
6842         if (!grow_one_stripe(conf, GFP_KERNEL)) {
6843             conf->min_nr_stripes = conf->max_nr_stripes;
6844             result = -ENOMEM;
6845             break;
6846         }
6847     mutex_unlock(&conf->cache_size_mutex);
6848
6849     return result;
6850 }
6851 EXPORT_SYMBOL(raid5_set_cache_size);
6852
6853 static ssize_t
6854 raid5_store_stripe_cache_size(struct mddev *mddev, const char *page, size_t len)
6855 {
6856     struct r5conf *conf;
6857     unsigned long new;
6858     int err;
6859
6860     if (len >= PAGE_SIZE)
6861         return -EINVAL;
6862     if (kstrtoul(page, 10, &new))
6863         return -EINVAL;
6864     err = mddev_lock(mddev);
6865     if (err)
6866         return err;
6867     conf = mddev->private;
6868     if (!conf)
6869         err = -ENODEV;
6870     else
6871         err = raid5_set_cache_size(mddev, new);
6872     mddev_unlock(mddev);
6873
6874     return err ?: len;
6875 }
6876
6877 static struct md_sysfs_entry
6878 raid5_stripecache_size = __ATTR(stripe_cache_size, S_IRUGO | S_IWUSR,
6879                 raid5_show_stripe_cache_size,
6880                 raid5_store_stripe_cache_size);
6881
6882 static ssize_t
6883 raid5_show_rmw_level(struct mddev  *mddev, char *page)
6884 {
6885     struct r5conf *conf = mddev->private;
6886     if (conf)
6887         return sprintf(page, "%d\n", conf->rmw_level);
6888     else
6889         return 0;
6890 }
6891
6892 static ssize_t
6893 raid5_store_rmw_level(struct mddev  *mddev, const char *page, size_t len)
6894 {
6895     struct r5conf *conf = mddev->private;
6896     unsigned long new;
6897
6898     if (!conf)
6899         return -ENODEV;
6900
6901     if (len >= PAGE_SIZE)
6902         return -EINVAL;
6903
6904     if (kstrtoul(page, 10, &new))
6905         return -EINVAL;
6906
6907     if (new != PARITY_DISABLE_RMW && !raid6_call.xor_syndrome)
6908         return -EINVAL;
6909
6910     if (new != PARITY_DISABLE_RMW &&
6911         new != PARITY_ENABLE_RMW &&
6912         new != PARITY_PREFER_RMW)
6913         return -EINVAL;
6914
6915     conf->rmw_level = new;
6916     return len;
6917 }
6918
6919 static struct md_sysfs_entry
6920 raid5_rmw_level = __ATTR(rmw_level, S_IRUGO | S_IWUSR,
6921              raid5_show_rmw_level,
6922              raid5_store_rmw_level);
6923
6924 static ssize_t
6925 raid5_show_stripe_size(struct mddev  *mddev, char *page)
6926 {
6927     struct r5conf *conf;
6928     int ret = 0;
6929
6930     spin_lock(&mddev->lock);
6931     conf = mddev->private;
6932     if (conf)
6933         ret = sprintf(page, "%lu\n", RAID5_STRIPE_SIZE(conf));
6934     spin_unlock(&mddev->lock);
6935     return ret;
6936 }
6937
6938 #if PAGE_SIZE != DEFAULT_STRIPE_SIZE
6939 static ssize_t
6940 raid5_store_stripe_size(struct mddev  *mddev, const char *page, size_t len)
6941 {
6942     struct r5conf *conf;
6943     unsigned long new;
6944     int err;
6945     int size;
6946
6947     if (len >= PAGE_SIZE)
6948         return -EINVAL;
6949     if (kstrtoul(page, 10, &new))
6950         return -EINVAL;
6951
6952     /*
6953      * The value should not be bigger than PAGE_SIZE. It requires to
6954      * be multiple of DEFAULT_STRIPE_SIZE and the value should be power
6955      * of two.
6956      */
6957     if (new % DEFAULT_STRIPE_SIZE != 0 ||
6958             new > PAGE_SIZE || new == 0 ||
6959             new != roundup_pow_of_two(new))
6960         return -EINVAL;
6961
6962     err = mddev_lock(mddev);
6963     if (err)
6964         return err;
6965
6966     conf = mddev->private;
6967     if (!conf) {
6968         err = -ENODEV;
6969         goto out_unlock;
6970     }
6971
6972     if (new == conf->stripe_size)
6973         goto out_unlock;
6974
6975     pr_debug("md/raid: change stripe_size from %lu to %lu\n",
6976             conf->stripe_size, new);
6977
6978     if (mddev->sync_thread ||
6979         test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
6980         mddev->reshape_position != MaxSector ||
6981         mddev->sysfs_active) {
6982         err = -EBUSY;
6983         goto out_unlock;
6984     }
6985
6986     mddev_suspend(mddev);
6987     mutex_lock(&conf->cache_size_mutex);
6988     size = conf->max_nr_stripes;
6989
6990     shrink_stripes(conf);
6991
6992     conf->stripe_size = new;
6993     conf->stripe_shift = ilog2(new) - 9;
6994     conf->stripe_sectors = new >> 9;
6995     if (grow_stripes(conf, size)) {
6996         pr_warn("md/raid:%s: couldn't allocate buffers\n",
6997                 mdname(mddev));
6998         err = -ENOMEM;
6999     }
7000     mutex_unlock(&conf->cache_size_mutex);
7001     mddev_resume(mddev);
7002
7003 out_unlock:
7004     mddev_unlock(mddev);
7005     return err ?: len;
7006 }
7007
7008 static struct md_sysfs_entry
7009 raid5_stripe_size = __ATTR(stripe_size, 0644,
7010              raid5_show_stripe_size,
7011              raid5_store_stripe_size);
7012 #else
7013 static struct md_sysfs_entry
7014 raid5_stripe_size = __ATTR(stripe_size, 0444,
7015              raid5_show_stripe_size,
7016              NULL);
7017 #endif
7018
7019 static ssize_t
7020 raid5_show_preread_threshold(struct mddev *mddev, char *page)
7021 {
7022     struct r5conf *conf;
7023     int ret = 0;
7024     spin_lock(&mddev->lock);
7025     conf = mddev->private;
7026     if (conf)
7027         ret = sprintf(page, "%d\n", conf->bypass_threshold);
7028     spin_unlock(&mddev->lock);
7029     return ret;
7030 }
7031
7032 static ssize_t
7033 raid5_store_preread_threshold(struct mddev *mddev, const char *page, size_t len)
7034 {
7035     struct r5conf *conf;
7036     unsigned long new;
7037     int err;
7038
7039     if (len >= PAGE_SIZE)
7040         return -EINVAL;
7041     if (kstrtoul(page, 10, &new))
7042         return -EINVAL;
7043
7044     err = mddev_lock(mddev);
7045     if (err)
7046         return err;
7047     conf = mddev->private;
7048     if (!conf)
7049         err = -ENODEV;
7050     else if (new > conf->min_nr_stripes)
7051         err = -EINVAL;
7052     else
7053         conf->bypass_threshold = new;
7054     mddev_unlock(mddev);
7055     return err ?: len;
7056 }
7057
7058 static struct md_sysfs_entry
7059 raid5_preread_bypass_threshold = __ATTR(preread_bypass_threshold,
7060                     S_IRUGO | S_IWUSR,
7061                     raid5_show_preread_threshold,
7062                     raid5_store_preread_threshold);
7063
7064 static ssize_t
7065 raid5_show_skip_copy(struct mddev *mddev, char *page)
7066 {
7067     struct r5conf *conf;
7068     int ret = 0;
7069     spin_lock(&mddev->lock);
7070     conf = mddev->private;
7071     if (conf)
7072         ret = sprintf(page, "%d\n", conf->skip_copy);
7073     spin_unlock(&mddev->lock);
7074     return ret;
7075 }
7076
7077 static ssize_t
7078 raid5_store_skip_copy(struct mddev *mddev, const char *page, size_t len)
7079 {
7080     struct r5conf *conf;
7081     unsigned long new;
7082     int err;
7083
7084     if (len >= PAGE_SIZE)
7085         return -EINVAL;
7086     if (kstrtoul(page, 10, &new))
7087         return -EINVAL;
7088     new = !!new;
7089
7090     err = mddev_lock(mddev);
7091     if (err)
7092         return err;
7093     conf = mddev->private;
7094     if (!conf)
7095         err = -ENODEV;
7096     else if (new != conf->skip_copy) {
7097         struct request_queue *q = mddev->queue;
7098
7099         mddev_suspend(mddev);
7100         conf->skip_copy = new;
7101         if (new)
7102             blk_queue_flag_set(QUEUE_FLAG_STABLE_WRITES, q);
7103         else
7104             blk_queue_flag_clear(QUEUE_FLAG_STABLE_WRITES, q);
7105         mddev_resume(mddev);
7106     }
7107     mddev_unlock(mddev);
7108     return err ?: len;
7109 }
7110
7111 static struct md_sysfs_entry
7112 raid5_skip_copy = __ATTR(skip_copy, S_IRUGO | S_IWUSR,
7113                     raid5_show_skip_copy,
7114                     raid5_store_skip_copy);
7115
7116 static ssize_t
7117 stripe_cache_active_show(struct mddev *mddev, char *page)
7118 {
7119     struct r5conf *conf = mddev->private;
7120     if (conf)
7121         return sprintf(page, "%d\n", atomic_read(&conf->active_stripes));
7122     else
7123         return 0;
7124 }
7125
7126 static struct md_sysfs_entry
7127 raid5_stripecache_active = __ATTR_RO(stripe_cache_active);
7128
7129 static ssize_t
7130 raid5_show_group_thread_cnt(struct mddev *mddev, char *page)
7131 {
7132     struct r5conf *conf;
7133     int ret = 0;
7134     spin_lock(&mddev->lock);
7135     conf = mddev->private;
7136     if (conf)
7137         ret = sprintf(page, "%d\n", conf->worker_cnt_per_group);
7138     spin_unlock(&mddev->lock);
7139     return ret;
7140 }
7141
7142 static int alloc_thread_groups(struct r5conf *conf, int cnt,
7143                    int *group_cnt,
7144                    struct r5worker_group **worker_groups);
7145 static ssize_t
7146 raid5_store_group_thread_cnt(struct mddev *mddev, const char *page, size_t len)
7147 {
7148     struct r5conf *conf;
7149     unsigned int new;
7150     int err;
7151     struct r5worker_group *new_groups, *old_groups;
7152     int group_cnt;
7153
7154     if (len >= PAGE_SIZE)
7155         return -EINVAL;
7156     if (kstrtouint(page, 10, &new))
7157         return -EINVAL;
7158     /* 8192 should be big enough */
7159     if (new > 8192)
7160         return -EINVAL;
7161
7162     err = mddev_lock(mddev);
7163     if (err)
7164         return err;
7165     conf = mddev->private;
7166     if (!conf)
7167         err = -ENODEV;
7168     else if (new != conf->worker_cnt_per_group) {
7169         mddev_suspend(mddev);
7170
7171         old_groups = conf->worker_groups;
7172         if (old_groups)
7173             flush_workqueue(raid5_wq);
7174
7175         err = alloc_thread_groups(conf, new, &group_cnt, &new_groups);
7176         if (!err) {
7177             spin_lock_irq(&conf->device_lock);
7178             conf->group_cnt = group_cnt;
7179             conf->worker_cnt_per_group = new;
7180             conf->worker_groups = new_groups;
7181             spin_unlock_irq(&conf->device_lock);
7182
7183             if (old_groups)
7184                 kfree(old_groups[0].workers);
7185             kfree(old_groups);
7186         }
7187         mddev_resume(mddev);
7188     }
7189     mddev_unlock(mddev);
7190
7191     return err ?: len;
7192 }
7193
7194 static struct md_sysfs_entry
7195 raid5_group_thread_cnt = __ATTR(group_thread_cnt, S_IRUGO | S_IWUSR,
7196                 raid5_show_group_thread_cnt,
7197                 raid5_store_group_thread_cnt);
7198
7199 static struct attribute *raid5_attrs[] =  {
7200     &raid5_stripecache_size.attr,
7201     &raid5_stripecache_active.attr,
7202     &raid5_preread_bypass_threshold.attr,
7203     &raid5_group_thread_cnt.attr,
7204     &raid5_skip_copy.attr,
7205     &raid5_rmw_level.attr,
7206     &raid5_stripe_size.attr,
7207     &r5c_journal_mode.attr,
7208     &ppl_write_hint.attr,
7209     NULL,
7210 };
7211 static const struct attribute_group raid5_attrs_group = {
7212     .name = NULL,
7213     .attrs = raid5_attrs,
7214 };
7215
7216 static int alloc_thread_groups(struct r5conf *conf, int cnt, int *group_cnt,
7217                    struct r5worker_group **worker_groups)
7218 {
7219     int i, j, k;
7220     ssize_t size;
7221     struct r5worker *workers;
7222
7223     if (cnt == 0) {
7224         *group_cnt = 0;
7225         *worker_groups = NULL;
7226         return 0;
7227     }
7228     *group_cnt = num_possible_nodes();
7229     size = sizeof(struct r5worker) * cnt;
7230     workers = kcalloc(size, *group_cnt, GFP_NOIO);
7231     *worker_groups = kcalloc(*group_cnt, sizeof(struct r5worker_group),
7232                  GFP_NOIO);
7233     if (!*worker_groups || !workers) {
7234         kfree(workers);
7235         kfree(*worker_groups);
7236         return -ENOMEM;
7237     }
7238
7239     for (i = 0; i < *group_cnt; i++) {
7240         struct r5worker_group *group;
7241
7242         group = &(*worker_groups)[i];
7243         INIT_LIST_HEAD(&group->handle_list);
7244         INIT_LIST_HEAD(&group->loprio_list);
7245         group->conf = conf;
7246         group->workers = workers + i * cnt;
7247
7248         for (j = 0; j < cnt; j++) {
7249             struct r5worker *worker = group->workers + j;
7250             worker->group = group;
7251             INIT_WORK(&worker->work, raid5_do_work);
7252
7253             for (k = 0; k < NR_STRIPE_HASH_LOCKS; k++)
7254                 INIT_LIST_HEAD(worker->temp_inactive_list + k);
7255         }
7256     }
7257
7258     return 0;
7259 }
7260
7261 static void free_thread_groups(struct r5conf *conf)
7262 {
7263     if (conf->worker_groups)
7264         kfree(conf->worker_groups[0].workers);
7265     kfree(conf->worker_groups);
7266     conf->worker_groups = NULL;
7267 }
7268
7269 static sector_t
7270 raid5_size(struct mddev *mddev, sector_t sectors, int raid_disks)
7271 {
7272     struct r5conf *conf = mddev->private;
7273
7274     if (!sectors)
7275         sectors = mddev->dev_sectors;
7276     if (!raid_disks)
7277         /* size is defined by the smallest of previous and new size */
7278         raid_disks = min(conf->raid_disks, conf->previous_raid_disks);
7279
7280     sectors &= ~((sector_t)conf->chunk_sectors - 1);
7281     sectors &= ~((sector_t)conf->prev_chunk_sectors - 1);
7282     return sectors * (raid_disks - conf->max_degraded);
7283 }
7284
7285 static void free_scratch_buffer(struct r5conf *conf, struct raid5_percpu *percpu)
7286 {
7287     safe_put_page(percpu->spare_page);
7288     percpu->spare_page = NULL;
7289     kvfree(percpu->scribble);
7290     percpu->scribble = NULL;
7291 }
7292
7293 static int alloc_scratch_buffer(struct r5conf *conf, struct raid5_percpu *percpu)
7294 {
7295     if (conf->level == 6 && !percpu->spare_page) {
7296         percpu->spare_page = alloc_page(GFP_KERNEL);
7297         if (!percpu->spare_page)
7298             return -ENOMEM;
7299     }
7300
7301     if (scribble_alloc(percpu,
7302                max(conf->raid_disks,
7303                    conf->previous_raid_disks),
7304                max(conf->chunk_sectors,
7305                    conf->prev_chunk_sectors)
7306                / RAID5_STRIPE_SECTORS(conf))) {
7307         free_scratch_buffer(conf, percpu);
7308         return -ENOMEM;
7309     }
7310
7311     local_lock_init(&percpu->lock);
7312     return 0;
7313 }
7314
7315 static int raid456_cpu_dead(unsigned int cpu, struct hlist_node *node)
7316 {
7317     struct r5conf *conf = hlist_entry_safe(node, struct r5conf, node);
7318
7319     free_scratch_buffer(conf, per_cpu_ptr(conf->percpu, cpu));
7320     return 0;
7321 }
7322
7323 static void raid5_free_percpu(struct r5conf *conf)
7324 {
7325     if (!conf->percpu)
7326         return;
7327
7328     cpuhp_state_remove_instance(CPUHP_MD_RAID5_PREPARE, &conf->node);
7329     free_percpu(conf->percpu);
7330 }
7331
7332 static void free_conf(struct r5conf *conf)
7333 {
7334     int i;
7335
7336     log_exit(conf);
7337
7338     unregister_shrinker(&conf->shrinker);
7339     free_thread_groups(conf);
7340     shrink_stripes(conf);
7341     raid5_free_percpu(conf);
7342     for (i = 0; i < conf->pool_size; i++)
7343         if (conf->disks[i].extra_page)
7344             put_page(conf->disks[i].extra_page);
7345     kfree(conf->disks);
7346     bioset_exit(&conf->bio_split);
7347     kfree(conf->stripe_hashtbl);
7348     kfree(conf->pending_data);
7349     kfree(conf);
7350 }
7351
7352 static int raid456_cpu_up_prepare(unsigned int cpu, struct hlist_node *node)
7353 {
7354     struct r5conf *conf = hlist_entry_safe(node, struct r5conf, node);
7355     struct raid5_percpu *percpu = per_cpu_ptr(conf->percpu, cpu);
7356
7357     if (alloc_scratch_buffer(conf, percpu)) {
7358         pr_warn("%s: failed memory allocation for cpu%u\n",
7359             __func__, cpu);
7360         return -ENOMEM;
7361     }
7362     return 0;
7363 }
7364
7365 static int raid5_alloc_percpu(struct r5conf *conf)
7366 {
7367     int err = 0;
7368
7369     conf->percpu = alloc_percpu(struct raid5_percpu);
7370     if (!conf->percpu)
7371         return -ENOMEM;
7372
7373     err = cpuhp_state_add_instance(CPUHP_MD_RAID5_PREPARE, &conf->node);
7374     if (!err) {
7375         conf->scribble_disks = max(conf->raid_disks,
7376             conf->previous_raid_disks);
7377         conf->scribble_sectors = max(conf->chunk_sectors,
7378             conf->prev_chunk_sectors);
7379     }
7380     return err;
7381 }
7382
7383 static unsigned long raid5_cache_scan(struct shrinker *shrink,
7384                       struct shrink_control *sc)
7385 {
7386     struct r5conf *conf = container_of(shrink, struct r5conf, shrinker);
7387     unsigned long ret = SHRINK_STOP;
7388
7389     if (mutex_trylock(&conf->cache_size_mutex)) {
7390         ret= 0;
7391         while (ret < sc->nr_to_scan &&
7392                conf->max_nr_stripes > conf->min_nr_stripes) {
7393             if (drop_one_stripe(conf) == 0) {
7394                 ret = SHRINK_STOP;
7395                 break;
7396             }
7397             ret++;
7398         }
7399         mutex_unlock(&conf->cache_size_mutex);
7400     }
7401     return ret;
7402 }
7403
7404 static unsigned long raid5_cache_count(struct shrinker *shrink,
7405                        struct shrink_control *sc)
7406 {
7407     struct r5conf *conf = container_of(shrink, struct r5conf, shrinker);
7408
7409     if (conf->max_nr_stripes < conf->min_nr_stripes)
7410         /* unlikely, but not impossible */
7411         return 0;
7412     return conf->max_nr_stripes - conf->min_nr_stripes;
7413 }
7414
7415 static struct r5conf *setup_conf(struct mddev *mddev)
7416 {
7417     struct r5conf *conf;
7418     int raid_disk, memory, max_disks;
7419     struct md_rdev *rdev;
7420     struct disk_info *disk;
7421     char pers_name[6];
7422     int i;
7423     int group_cnt;
7424     struct r5worker_group *new_group;
7425     int ret = -ENOMEM;
7426
7427     if (mddev->new_level != 5
7428         && mddev->new_level != 4
7429         && mddev->new_level != 6) {
7430         pr_warn("md/raid:%s: raid level not set to 4/5/6 (%d)\n",
7431             mdname(mddev), mddev->new_level);
7432         return ERR_PTR(-EIO);
7433     }
7434     if ((mddev->new_level == 5
7435          && !algorithm_valid_raid5(mddev->new_layout)) ||
7436         (mddev->new_level == 6
7437          && !algorithm_valid_raid6(mddev->new_layout))) {
7438         pr_warn("md/raid:%s: layout %d not supported\n",
7439             mdname(mddev), mddev->new_layout);
7440         return ERR_PTR(-EIO);
7441     }
7442     if (mddev->new_level == 6 && mddev->raid_disks < 4) {
7443         pr_warn("md/raid:%s: not enough configured devices (%d, minimum 4)\n",
7444             mdname(mddev), mddev->raid_disks);
7445         return ERR_PTR(-EINVAL);
7446     }
7447
7448     if (!mddev->new_chunk_sectors ||
7449         (mddev->new_chunk_sectors << 9) % PAGE_SIZE ||
7450         !is_power_of_2(mddev->new_chunk_sectors)) {
7451         pr_warn("md/raid:%s: invalid chunk size %d\n",
7452             mdname(mddev), mddev->new_chunk_sectors << 9);
7453         return ERR_PTR(-EINVAL);
7454     }
7455
7456     conf = kzalloc(sizeof(struct r5conf), GFP_KERNEL);
7457     if (conf == NULL)
7458         goto abort;
7459
7460 #if PAGE_SIZE != DEFAULT_STRIPE_SIZE
7461     conf->stripe_size = DEFAULT_STRIPE_SIZE;
7462     conf->stripe_shift = ilog2(DEFAULT_STRIPE_SIZE) - 9;
7463     conf->stripe_sectors = DEFAULT_STRIPE_SIZE >> 9;
7464 #endif
7465     INIT_LIST_HEAD(&conf->free_list);
7466     INIT_LIST_HEAD(&conf->pending_list);
7467     conf->pending_data = kcalloc(PENDING_IO_MAX,
7468                      sizeof(struct r5pending_data),
7469                      GFP_KERNEL);
7470     if (!conf->pending_data)
7471         goto abort;
7472     for (i = 0; i < PENDING_IO_MAX; i++)
7473         list_add(&conf->pending_data[i].sibling, &conf->free_list);
7474     /* Don't enable multi-threading by default*/
7475     if (!alloc_thread_groups(conf, 0, &group_cnt, &new_group)) {
7476         conf->group_cnt = group_cnt;
7477         conf->worker_cnt_per_group = 0;
7478         conf->worker_groups = new_group;
7479     } else
7480         goto abort;
7481     spin_lock_init(&conf->device_lock);
7482     seqcount_spinlock_init(&conf->gen_lock, &conf->device_lock);
7483     mutex_init(&conf->cache_size_mutex);
7484
7485     init_waitqueue_head(&conf->wait_for_quiescent);
7486     init_waitqueue_head(&conf->wait_for_stripe);
7487     init_waitqueue_head(&conf->wait_for_overlap);
7488     INIT_LIST_HEAD(&conf->handle_list);
7489     INIT_LIST_HEAD(&conf->loprio_list);
7490     INIT_LIST_HEAD(&conf->hold_list);
7491     INIT_LIST_HEAD(&conf->delayed_list);
7492     INIT_LIST_HEAD(&conf->bitmap_list);
7493     init_llist_head(&conf->released_stripes);
7494     atomic_set(&conf->active_stripes, 0);
7495     atomic_set(&conf->preread_active_stripes, 0);
7496     atomic_set(&conf->active_aligned_reads, 0);
7497     spin_lock_init(&conf->pending_bios_lock);
7498     conf->batch_bio_dispatch = true;
7499     rdev_for_each(rdev, mddev) {
7500         if (test_bit(Journal, &rdev->flags))
7501             continue;
7502         if (bdev_nonrot(rdev->bdev)) {
7503             conf->batch_bio_dispatch = false;
7504             break;
7505         }
7506     }
7507
7508     conf->bypass_threshold = BYPASS_THRESHOLD;
7509     conf->recovery_disabled = mddev->recovery_disabled - 1;
7510
7511     conf->raid_disks = mddev->raid_disks;
7512     if (mddev->reshape_position == MaxSector)
7513         conf->previous_raid_disks = mddev->raid_disks;
7514     else
7515         conf->previous_raid_disks = mddev->raid_disks - mddev->delta_disks;
7516     max_disks = max(conf->raid_disks, conf->previous_raid_disks);
7517
7518     conf->disks = kcalloc(max_disks, sizeof(struct disk_info),
7519                   GFP_KERNEL);
7520
7521     if (!conf->disks)
7522         goto abort;
7523
7524     for (i = 0; i < max_disks; i++) {
7525         conf->disks[i].extra_page = alloc_page(GFP_KERNEL);
7526         if (!conf->disks[i].extra_page)
7527             goto abort;
7528     }
7529
7530     ret = bioset_init(&conf->bio_split, BIO_POOL_SIZE, 0, 0);
7531     if (ret)
7532         goto abort;
7533     conf->mddev = mddev;
7534
7535     ret = -ENOMEM;
7536     conf->stripe_hashtbl = kzalloc(PAGE_SIZE, GFP_KERNEL);
7537     if (!conf->stripe_hashtbl)
7538         goto abort;
7539
7540     /* We init hash_locks[0] separately to that it can be used
7541      * as the reference lock in the spin_lock_nest_lock() call
7542      * in lock_all_device_hash_locks_irq in order to convince
7543      * lockdep that we know what we are doing.
7544      */
7545     spin_lock_init(conf->hash_locks);
7546     for (i = 1; i < NR_STRIPE_HASH_LOCKS; i++)
7547         spin_lock_init(conf->hash_locks + i);
7548
7549     for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
7550         INIT_LIST_HEAD(conf->inactive_list + i);
7551
7552     for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
7553         INIT_LIST_HEAD(conf->temp_inactive_list + i);
7554
7555     atomic_set(&conf->r5c_cached_full_stripes, 0);
7556     INIT_LIST_HEAD(&conf->r5c_full_stripe_list);
7557     atomic_set(&conf->r5c_cached_partial_stripes, 0);
7558     INIT_LIST_HEAD(&conf->r5c_partial_stripe_list);
7559     atomic_set(&conf->r5c_flushing_full_stripes, 0);
7560     atomic_set(&conf->r5c_flushing_partial_stripes, 0);
7561
7562     conf->level = mddev->new_level;
7563     conf->chunk_sectors = mddev->new_chunk_sectors;
7564     ret = raid5_alloc_percpu(conf);
7565     if (ret)
7566         goto abort;
7567
7568     pr_debug("raid456: run(%s) called.\n", mdname(mddev));
7569
7570     ret = -EIO;
7571     rdev_for_each(rdev, mddev) {
7572         raid_disk = rdev->raid_disk;
7573         if (raid_disk >= max_disks
7574             || raid_disk < 0 || test_bit(Journal, &rdev->flags))
7575             continue;
7576         disk = conf->disks + raid_disk;
7577
7578         if (test_bit(Replacement, &rdev->flags)) {
7579             if (disk->replacement)
7580                 goto abort;
7581             RCU_INIT_POINTER(disk->replacement, rdev);
7582         } else {
7583             if (disk->rdev)
7584                 goto abort;
7585             RCU_INIT_POINTER(disk->rdev, rdev);
7586         }
7587
7588         if (test_bit(In_sync, &rdev->flags)) {
7589             pr_info("md/raid:%s: device %pg operational as raid disk %d\n",
7590                 mdname(mddev), rdev->bdev, raid_disk);
7591         } else if (rdev->saved_raid_disk != raid_disk)
7592             /* Cannot rely on bitmap to complete recovery */
7593             conf->fullsync = 1;
7594     }
7595
7596     conf->level = mddev->new_level;
7597     if (conf->level == 6) {
7598         conf->max_degraded = 2;
7599         if (raid6_call.xor_syndrome)
7600             conf->rmw_level = PARITY_ENABLE_RMW;
7601         else
7602             conf->rmw_level = PARITY_DISABLE_RMW;
7603     } else {
7604         conf->max_degraded = 1;
7605         conf->rmw_level = PARITY_ENABLE_RMW;
7606     }
7607     conf->algorithm = mddev->new_layout;
7608     conf->reshape_progress = mddev->reshape_position;
7609     if (conf->reshape_progress != MaxSector) {
7610         conf->prev_chunk_sectors = mddev->chunk_sectors;
7611         conf->prev_algo = mddev->layout;
7612     } else {
7613         conf->prev_chunk_sectors = conf->chunk_sectors;
7614         conf->prev_algo = conf->algorithm;
7615     }
7616
7617     conf->min_nr_stripes = NR_STRIPES;
7618     if (mddev->reshape_position != MaxSector) {
7619         int stripes = max_t(int,
7620             ((mddev->chunk_sectors << 9) / RAID5_STRIPE_SIZE(conf)) * 4,
7621             ((mddev->new_chunk_sectors << 9) / RAID5_STRIPE_SIZE(conf)) * 4);
7622         conf->min_nr_stripes = max(NR_STRIPES, stripes);
7623         if (conf->min_nr_stripes != NR_STRIPES)
7624             pr_info("md/raid:%s: force stripe size %d for reshape\n",
7625                 mdname(mddev), conf->min_nr_stripes);
7626     }
7627     memory = conf->min_nr_stripes * (sizeof(struct stripe_head) +
7628          max_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024;
7629     atomic_set(&conf->empty_inactive_list_nr, NR_STRIPE_HASH_LOCKS);
7630     if (grow_stripes(conf, conf->min_nr_stripes)) {
7631         pr_warn("md/raid:%s: couldn't allocate %dkB for buffers\n",
7632             mdname(mddev), memory);
7633         ret = -ENOMEM;
7634         goto abort;
7635     } else
7636         pr_debug("md/raid:%s: allocated %dkB\n", mdname(mddev), memory);
7637     /*
7638      * Losing a stripe head costs more than the time to refill it,
7639      * it reduces the queue depth and so can hurt throughput.
7640      * So set it rather large, scaled by number of devices.
7641      */
7642     conf->shrinker.seeks = DEFAULT_SEEKS * conf->raid_disks * 4;
7643     conf->shrinker.scan_objects = raid5_cache_scan;
7644     conf->shrinker.count_objects = raid5_cache_count;
7645     conf->shrinker.batch = 128;
7646     conf->shrinker.flags = 0;
7647     ret = register_shrinker(&conf->shrinker, "md-raid5:%s", mdname(mddev));
7648     if (ret) {
7649         pr_warn("md/raid:%s: couldn't register shrinker.\n",
7650             mdname(mddev));
7651         goto abort;
7652     }
7653
7654     sprintf(pers_name, "raid%d", mddev->new_level);
7655     conf->thread = md_register_thread(raid5d, mddev, pers_name);
7656     if (!conf->thread) {
7657         pr_warn("md/raid:%s: couldn't allocate thread.\n",
7658             mdname(mddev));
7659         ret = -ENOMEM;
7660         goto abort;
7661     }
7662
7663     return conf;
7664
7665  abort:
7666     if (conf)
7667         free_conf(conf);
7668     return ERR_PTR(ret);
7669 }
7670
7671 static int only_parity(int raid_disk, int algo, int raid_disks, int max_degraded)
7672 {
7673     switch (algo) {
7674     case ALGORITHM_PARITY_0:
7675         if (raid_disk < max_degraded)
7676             return 1;
7677         break;
7678     case ALGORITHM_PARITY_N:
7679         if (raid_disk >= raid_disks - max_degraded)
7680             return 1;
7681         break;
7682     case ALGORITHM_PARITY_0_6:
7683         if (raid_disk == 0 ||
7684             raid_disk == raid_disks - 1)
7685             return 1;
7686         break;
7687     case ALGORITHM_LEFT_ASYMMETRIC_6:
7688     case ALGORITHM_RIGHT_ASYMMETRIC_6:
7689     case ALGORITHM_LEFT_SYMMETRIC_6:
7690     case ALGORITHM_RIGHT_SYMMETRIC_6:
7691         if (raid_disk == raid_disks - 1)
7692             return 1;
7693     }
7694     return 0;
7695 }
7696
7697 static void raid5_set_io_opt(struct r5conf *conf)
7698 {
7699     blk_queue_io_opt(conf->mddev->queue, (conf->chunk_sectors << 9) *
7700              (conf->raid_disks - conf->max_degraded));
7701 }
7702
7703 static int raid5_run(struct mddev *mddev)
7704 {
7705     struct r5conf *conf;
7706     int working_disks = 0;
7707     int dirty_parity_disks = 0;
7708     struct md_rdev *rdev;
7709     struct md_rdev *journal_dev = NULL;
7710     sector_t reshape_offset = 0;
7711     int i, ret = 0;
7712     long long min_offset_diff = 0;
7713     int first = 1;
7714
7715     if (acct_bioset_init(mddev)) {
7716         pr_err("md/raid456:%s: alloc acct bioset failed.\n", mdname(mddev));
7717         return -ENOMEM;
7718     }
7719
7720     if (mddev_init_writes_pending(mddev) < 0) {
7721         ret = -ENOMEM;
7722         goto exit_acct_set;
7723     }
7724
7725     if (mddev->recovery_cp != MaxSector)
7726         pr_notice("md/raid:%s: not clean -- starting background reconstruction\n",
7727               mdname(mddev));
7728
7729     rdev_for_each(rdev, mddev) {
7730         long long diff;
7731
7732         if (test_bit(Journal, &rdev->flags)) {
7733             journal_dev = rdev;
7734             continue;
7735         }
7736         if (rdev->raid_disk < 0)
7737             continue;
7738         diff = (rdev->new_data_offset - rdev->data_offset);
7739         if (first) {
7740             min_offset_diff = diff;
7741             first = 0;
7742         } else if (mddev->reshape_backwards &&
7743              diff < min_offset_diff)
7744             min_offset_diff = diff;
7745         else if (!mddev->reshape_backwards &&
7746              diff > min_offset_diff)
7747             min_offset_diff = diff;
7748     }
7749
7750     if ((test_bit(MD_HAS_JOURNAL, &mddev->flags) || journal_dev) &&
7751         (mddev->bitmap_info.offset || mddev->bitmap_info.file)) {
7752         pr_notice("md/raid:%s: array cannot have both journal and bitmap\n",
7753               mdname(mddev));
7754         ret = -EINVAL;
7755         goto exit_acct_set;
7756     }
7757
7758     if (mddev->reshape_position != MaxSector) {
7759         /* Check that we can continue the reshape.
7760          * Difficulties arise if the stripe we would write to
7761          * next is at or after the stripe we would read from next.
7762          * For a reshape that changes the number of devices, this
7763          * is only possible for a very short time, and mdadm makes
7764          * sure that time appears to have past before assembling
7765          * the array.  So we fail if that time hasn't passed.
7766          * For a reshape that keeps the number of devices the same
7767          * mdadm must be monitoring the reshape can keeping the
7768          * critical areas read-only and backed up.  It will start
7769          * the array in read-only mode, so we check for that.
7770          */
7771         sector_t here_new, here_old;
7772         int old_disks;
7773         int max_degraded = (mddev->level == 6 ? 2 : 1);
7774         int chunk_sectors;
7775         int new_data_disks;
7776
7777         if (journal_dev) {
7778             pr_warn("md/raid:%s: don't support reshape with journal - aborting.\n",
7779                 mdname(mddev));
7780             ret = -EINVAL;
7781             goto exit_acct_set;
7782         }
7783
7784         if (mddev->new_level != mddev->level) {
7785             pr_warn("md/raid:%s: unsupported reshape required - aborting.\n",
7786                 mdname(mddev));
7787             ret = -EINVAL;
7788             goto exit_acct_set;
7789         }
7790         old_disks = mddev->raid_disks - mddev->delta_disks;
7791         /* reshape_position must be on a new-stripe boundary, and one
7792          * further up in new geometry must map after here in old
7793          * geometry.
7794          * If the chunk sizes are different, then as we perform reshape
7795          * in units of the largest of the two, reshape_position needs
7796          * be a multiple of the largest chunk size times new data disks.
7797          */
7798         here_new = mddev->reshape_position;
7799         chunk_sectors = max(mddev->chunk_sectors, mddev->new_chunk_sectors);
7800         new_data_disks = mddev->raid_disks - max_degraded;
7801         if (sector_div(here_new, chunk_sectors * new_data_disks)) {
7802             pr_warn("md/raid:%s: reshape_position not on a stripe boundary\n",
7803                 mdname(mddev));
7804             ret = -EINVAL;
7805             goto exit_acct_set;
7806         }
7807         reshape_offset = here_new * chunk_sectors;
7808         /* here_new is the stripe we will write to */
7809         here_old = mddev->reshape_position;
7810         sector_div(here_old, chunk_sectors * (old_disks-max_degraded));
7811         /* here_old is the first stripe that we might need to read
7812          * from */
7813         if (mddev->delta_disks == 0) {
7814             /* We cannot be sure it is safe to start an in-place
7815              * reshape.  It is only safe if user-space is monitoring
7816              * and taking constant backups.
7817              * mdadm always starts a situation like this in
7818              * readonly mode so it can take control before
7819              * allowing any writes.  So just check for that.
7820              */
7821             if (abs(min_offset_diff) >= mddev->chunk_sectors &&
7822                 abs(min_offset_diff) >= mddev->new_chunk_sectors)
7823                 /* not really in-place - so OK */;
7824             else if (mddev->ro == 0) {
7825                 pr_warn("md/raid:%s: in-place reshape must be started in read-only mode - aborting\n",
7826                     mdname(mddev));
7827                 ret = -EINVAL;
7828                 goto exit_acct_set;
7829             }
7830         } else if (mddev->reshape_backwards
7831             ? (here_new * chunk_sectors + min_offset_diff <=
7832                here_old * chunk_sectors)
7833             : (here_new * chunk_sectors >=
7834                here_old * chunk_sectors + (-min_offset_diff))) {
7835             /* Reading from the same stripe as writing to - bad */
7836             pr_warn("md/raid:%s: reshape_position too early for auto-recovery - aborting.\n",
7837                 mdname(mddev));
7838             ret = -EINVAL;
7839             goto exit_acct_set;
7840         }
7841         pr_debug("md/raid:%s: reshape will continue\n", mdname(mddev));
7842         /* OK, we should be able to continue; */
7843     } else {
7844         BUG_ON(mddev->level != mddev->new_level);
7845         BUG_ON(mddev->layout != mddev->new_layout);
7846         BUG_ON(mddev->chunk_sectors != mddev->new_chunk_sectors);
7847         BUG_ON(mddev->delta_disks != 0);
7848     }
7849
7850     if (test_bit(MD_HAS_JOURNAL, &mddev->flags) &&
7851         test_bit(MD_HAS_PPL, &mddev->flags)) {
7852         pr_warn("md/raid:%s: using journal device and PPL not allowed - disabling PPL\n",
7853             mdname(mddev));
7854         clear_bit(MD_HAS_PPL, &mddev->flags);
7855         clear_bit(MD_HAS_MULTIPLE_PPLS, &mddev->flags);
7856     }
7857
7858     if (mddev->private == NULL)
7859         conf = setup_conf(mddev);
7860     else
7861         conf = mddev->private;
7862
7863     if (IS_ERR(conf)) {
7864         ret = PTR_ERR(conf);
7865         goto exit_acct_set;
7866     }
7867
7868     if (test_bit(MD_HAS_JOURNAL, &mddev->flags)) {
7869         if (!journal_dev) {
7870             pr_warn("md/raid:%s: journal disk is missing, force array readonly\n",
7871                 mdname(mddev));
7872             mddev->ro = 1;
7873             set_disk_ro(mddev->gendisk, 1);
7874         } else if (mddev->recovery_cp == MaxSector)
7875             set_bit(MD_JOURNAL_CLEAN, &mddev->flags);
7876     }
7877
7878     conf->min_offset_diff = min_offset_diff;
7879     mddev->thread = conf->thread;
7880     conf->thread = NULL;
7881     mddev->private = conf;
7882
7883     for (i = 0; i < conf->raid_disks && conf->previous_raid_disks;
7884          i++) {
7885         rdev = rdev_mdlock_deref(mddev, conf->disks[i].rdev);
7886         if (!rdev && conf->disks[i].replacement) {
7887             /* The replacement is all we have yet */
7888             rdev = rdev_mdlock_deref(mddev,
7889                          conf->disks[i].replacement);
7890             conf->disks[i].replacement = NULL;
7891             clear_bit(Replacement, &rdev->flags);
7892             rcu_assign_pointer(conf->disks[i].rdev, rdev);
7893         }
7894         if (!rdev)
7895             continue;
7896         if (rcu_access_pointer(conf->disks[i].replacement) &&
7897             conf->reshape_progress != MaxSector) {
7898             /* replacements and reshape simply do not mix. */
7899             pr_warn("md: cannot handle concurrent replacement and reshape.\n");
7900             goto abort;
7901         }
7902         if (test_bit(In_sync, &rdev->flags)) {
7903             working_disks++;
7904             continue;
7905         }
7906         /* This disc is not fully in-sync.  However if it
7907          * just stored parity (beyond the recovery_offset),
7908          * when we don't need to be concerned about the
7909          * array being dirty.
7910          * When reshape goes 'backwards', we never have
7911          * partially completed devices, so we only need
7912          * to worry about reshape going forwards.
7913          */
7914         /* Hack because v0.91 doesn't store recovery_offset properly. */
7915         if (mddev->major_version == 0 &&
7916             mddev->minor_version > 90)
7917             rdev->recovery_offset = reshape_offset;
7918
7919         if (rdev->recovery_offset < reshape_offset) {
7920             /* We need to check old and new layout */
7921             if (!only_parity(rdev->raid_disk,
7922                      conf->algorithm,
7923                      conf->raid_disks,
7924                      conf->max_degraded))
7925                 continue;
7926         }
7927         if (!only_parity(rdev->raid_disk,
7928                  conf->prev_algo,
7929                  conf->previous_raid_disks,
7930                  conf->max_degraded))
7931             continue;
7932         dirty_parity_disks++;
7933     }
7934
7935     /*
7936      * 0 for a fully functional array, 1 or 2 for a degraded array.
7937      */
7938     mddev->degraded = raid5_calc_degraded(conf);
7939
7940     if (has_failed(conf)) {
7941         pr_crit("md/raid:%s: not enough operational devices (%d/%d failed)\n",
7942             mdname(mddev), mddev->degraded, conf->raid_disks);
7943         goto abort;
7944     }
7945
7946     /* device size must be a multiple of chunk size */
7947     mddev->dev_sectors &= ~((sector_t)mddev->chunk_sectors - 1);
7948     mddev->resync_max_sectors = mddev->dev_sectors;
7949
7950     if (mddev->degraded > dirty_parity_disks &&
7951         mddev->recovery_cp != MaxSector) {
7952         if (test_bit(MD_HAS_PPL, &mddev->flags))
7953             pr_crit("md/raid:%s: starting dirty degraded array with PPL.\n",
7954                 mdname(mddev));
7955         else if (mddev->ok_start_degraded)
7956             pr_crit("md/raid:%s: starting dirty degraded array - data corruption possible.\n",
7957                 mdname(mddev));
7958         else {
7959             pr_crit("md/raid:%s: cannot start dirty degraded array.\n",
7960                 mdname(mddev));
7961             goto abort;
7962         }
7963     }
7964
7965     pr_info("md/raid:%s: raid level %d active with %d out of %d devices, algorithm %d\n",
7966         mdname(mddev), conf->level,
7967         mddev->raid_disks-mddev->degraded, mddev->raid_disks,
7968         mddev->new_layout);
7969
7970     print_raid5_conf(conf);
7971
7972     if (conf->reshape_progress != MaxSector) {
7973         conf->reshape_safe = conf->reshape_progress;
7974         atomic_set(&conf->reshape_stripes, 0);
7975         clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
7976         clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
7977         set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
7978         set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
7979         mddev->sync_thread = md_register_thread(md_do_sync, mddev,
7980                             "reshape");
7981         if (!mddev->sync_thread)
7982             goto abort;
7983     }
7984
7985     /* Ok, everything is just fine now */
7986     if (mddev->to_remove == &raid5_attrs_group)
7987         mddev->to_remove = NULL;
7988     else if (mddev->kobj.sd &&
7989         sysfs_create_group(&mddev->kobj, &raid5_attrs_group))
7990         pr_warn("raid5: failed to create sysfs attributes for %s\n",
7991             mdname(mddev));
7992     md_set_array_sectors(mddev, raid5_size(mddev, 0, 0));
7993
7994     if (mddev->queue) {
7995         int chunk_size;
7996         /* read-ahead size must cover two whole stripes, which
7997          * is 2 * (datadisks) * chunksize where 'n' is the
7998          * number of raid devices
7999          */
8000         int data_disks = conf->previous_raid_disks - conf->max_degraded;
8001         int stripe = data_disks *
8002             ((mddev->chunk_sectors << 9) / PAGE_SIZE);
8003
8004         chunk_size = mddev->chunk_sectors << 9;
8005         blk_queue_io_min(mddev->queue, chunk_size);
8006         raid5_set_io_opt(conf);
8007         mddev->queue->limits.raid_partial_stripes_expensive = 1;
8008         /*
8009          * We can only discard a whole stripe. It doesn't make sense to
8010          * discard data disk but write parity disk
8011          */
8012         stripe = stripe * PAGE_SIZE;
8013         stripe = roundup_pow_of_two(stripe);
8014         mddev->queue->limits.discard_granularity = stripe;
8015
8016         blk_queue_max_write_zeroes_sectors(mddev->queue, 0);
8017
8018         rdev_for_each(rdev, mddev) {
8019             disk_stack_limits(mddev->gendisk, rdev->bdev,
8020                       rdev->data_offset << 9);
8021             disk_stack_limits(mddev->gendisk, rdev->bdev,
8022                       rdev->new_data_offset << 9);
8023         }
8024
8025         /*
8026          * zeroing is required, otherwise data
8027          * could be lost. Consider a scenario: discard a stripe
8028          * (the stripe could be inconsistent if
8029          * discard_zeroes_data is 0); write one disk of the
8030          * stripe (the stripe could be inconsistent again
8031          * depending on which disks are used to calculate
8032          * parity); the disk is broken; The stripe data of this
8033          * disk is lost.
8034          *
8035          * We only allow DISCARD if the sysadmin has confirmed that
8036          * only safe devices are in use by setting a module parameter.
8037          * A better idea might be to turn DISCARD into WRITE_ZEROES
8038          * requests, as that is required to be safe.
8039          */
8040         if (!devices_handle_discard_safely ||
8041             mddev->queue->limits.max_discard_sectors < (stripe >> 9) ||
8042             mddev->queue->limits.discard_granularity < stripe)
8043             blk_queue_max_discard_sectors(mddev->queue, 0);
8044
8045         /*
8046          * Requests require having a bitmap for each stripe.
8047          * Limit the max sectors based on this.
8048          */
8049         blk_queue_max_hw_sectors(mddev->queue,
8050             RAID5_MAX_REQ_STRIPES << RAID5_STRIPE_SHIFT(conf));
8051
8052         /* No restrictions on the number of segments in the request */
8053         blk_queue_max_segments(mddev->queue, USHRT_MAX);
8054     }
8055
8056     if (log_init(conf, journal_dev, raid5_has_ppl(conf)))
8057         goto abort;
8058
8059     return 0;
8060 abort:
8061     md_unregister_thread(&mddev->thread);
8062     print_raid5_conf(conf);
8063     free_conf(conf);
8064     mddev->private = NULL;
8065     pr_warn("md/raid:%s: failed to run raid set.\n", mdname(mddev));
8066     ret = -EIO;
8067 exit_acct_set:
8068     acct_bioset_exit(mddev);
8069     return ret;
8070 }
8071
8072 static void raid5_free(struct mddev *mddev, void *priv)
8073 {
8074     struct r5conf *conf = priv;
8075
8076     free_conf(conf);
8077     acct_bioset_exit(mddev);
8078     mddev->to_remove = &raid5_attrs_group;
8079 }
8080
8081 static void raid5_status(struct seq_file *seq, struct mddev *mddev)
8082 {
8083     struct r5conf *conf = mddev->private;
8084     int i;
8085
8086     seq_printf(seq, " level %d, %dk chunk, algorithm %d", mddev->level,
8087         conf->chunk_sectors / 2, mddev->layout);
8088     seq_printf (seq, " [%d/%d] [", conf->raid_disks, conf->raid_disks - mddev->degraded);
8089     rcu_read_lock();
8090     for (i = 0; i < conf->raid_disks; i++) {
8091         struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
8092         seq_printf (seq, "%s", rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_");
8093     }
8094     rcu_read_unlock();
8095     seq_printf (seq, "]");
8096 }
8097
8098 static void print_raid5_conf (struct r5conf *conf)
8099 {
8100     struct md_rdev *rdev;
8101     int i;
8102
8103     pr_debug("RAID conf printout:\n");
8104     if (!conf) {
8105         pr_debug("(conf==NULL)\n");
8106         return;
8107     }
8108     pr_debug(" --- level:%d rd:%d wd:%d\n", conf->level,
8109            conf->raid_disks,
8110            conf->raid_disks - conf->mddev->degraded);
8111
8112     rcu_read_lock();
8113     for (i = 0; i < conf->raid_disks; i++) {
8114         rdev = rcu_dereference(conf->disks[i].rdev);
8115         if (rdev)
8116             pr_debug(" disk %d, o:%d, dev:%pg\n",
8117                    i, !test_bit(Faulty, &rdev->flags),
8118                    rdev->bdev);
8119     }
8120     rcu_read_unlock();
8121 }
8122
8123 static int raid5_spare_active(struct mddev *mddev)
8124 {
8125     int i;
8126     struct r5conf *conf = mddev->private;
8127     struct md_rdev *rdev, *replacement;
8128     int count = 0;
8129     unsigned long flags;
8130
8131     for (i = 0; i < conf->raid_disks; i++) {
8132         rdev = rdev_mdlock_deref(mddev, conf->disks[i].rdev);
8133         replacement = rdev_mdlock_deref(mddev,
8134                         conf->disks[i].replacement);
8135         if (replacement
8136             && replacement->recovery_offset == MaxSector
8137             && !test_bit(Faulty, &replacement->flags)
8138             && !test_and_set_bit(In_sync, &replacement->flags)) {
8139             /* Replacement has just become active. */
8140             if (!rdev
8141                 || !test_and_clear_bit(In_sync, &rdev->flags))
8142                 count++;
8143             if (rdev) {
8144                 /* Replaced device not technically faulty,
8145                  * but we need to be sure it gets removed
8146                  * and never re-added.
8147                  */
8148                 set_bit(Faulty, &rdev->flags);
8149                 sysfs_notify_dirent_safe(
8150                     rdev->sysfs_state);
8151             }
8152             sysfs_notify_dirent_safe(replacement->sysfs_state);
8153         } else if (rdev
8154             && rdev->recovery_offset == MaxSector
8155             && !test_bit(Faulty, &rdev->flags)
8156             && !test_and_set_bit(In_sync, &rdev->flags)) {
8157             count++;
8158             sysfs_notify_dirent_safe(rdev->sysfs_state);
8159         }
8160     }
8161     spin_lock_irqsave(&conf->device_lock, flags);
8162     mddev->degraded = raid5_calc_degraded(conf);
8163     spin_unlock_irqrestore(&conf->device_lock, flags);
8164     print_raid5_conf(conf);
8165     return count;
8166 }
8167
8168 static int raid5_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
8169 {
8170     struct r5conf *conf = mddev->private;
8171     int err = 0;
8172     int number = rdev->raid_disk;
8173     struct md_rdev __rcu **rdevp;
8174     struct disk_info *p;
8175     struct md_rdev *tmp;
8176
8177     print_raid5_conf(conf);
8178     if (test_bit(Journal, &rdev->flags) && conf->log) {
8179         /*
8180          * we can't wait pending write here, as this is called in
8181          * raid5d, wait will deadlock.
8182          * neilb: there is no locking about new writes here,
8183          * so this cannot be safe.
8184          */
8185         if (atomic_read(&conf->active_stripes) ||
8186             atomic_read(&conf->r5c_cached_full_stripes) ||
8187             atomic_read(&conf->r5c_cached_partial_stripes)) {
8188             return -EBUSY;
8189         }
8190         log_exit(conf);
8191         return 0;
8192     }
8193     if (unlikely(number >= conf->pool_size))
8194         return 0;
8195     p = conf->disks + number;
8196     if (rdev == rcu_access_pointer(p->rdev))
8197         rdevp = &p->rdev;
8198     else if (rdev == rcu_access_pointer(p->replacement))
8199         rdevp = &p->replacement;
8200     else
8201         return 0;
8202
8203     if (number >= conf->raid_disks &&
8204         conf->reshape_progress == MaxSector)
8205         clear_bit(In_sync, &rdev->flags);
8206
8207     if (test_bit(In_sync, &rdev->flags) ||
8208         atomic_read(&rdev->nr_pending)) {
8209         err = -EBUSY;
8210         goto abort;
8211     }
8212     /* Only remove non-faulty devices if recovery
8213      * isn't possible.
8214      */
8215     if (!test_bit(Faulty, &rdev->flags) &&
8216         mddev->recovery_disabled != conf->recovery_disabled &&
8217         !has_failed(conf) &&
8218         (!rcu_access_pointer(p->replacement) ||
8219          rcu_access_pointer(p->replacement) == rdev) &&
8220         number < conf->raid_disks) {
8221         err = -EBUSY;
8222         goto abort;
8223     }
8224     *rdevp = NULL;
8225     if (!test_bit(RemoveSynchronized, &rdev->flags)) {
8226         lockdep_assert_held(&mddev->reconfig_mutex);
8227         synchronize_rcu();
8228         if (atomic_read(&rdev->nr_pending)) {
8229             /* lost the race, try later */
8230             err = -EBUSY;
8231             rcu_assign_pointer(*rdevp, rdev);
8232         }
8233     }
8234     if (!err) {
8235         err = log_modify(conf, rdev, false);
8236         if (err)
8237             goto abort;
8238     }
8239
8240     tmp = rcu_access_pointer(p->replacement);
8241     if (tmp) {
8242         /* We must have just cleared 'rdev' */
8243         rcu_assign_pointer(p->rdev, tmp);
8244         clear_bit(Replacement, &tmp->flags);
8245         smp_mb(); /* Make sure other CPUs may see both as identical
8246                * but will never see neither - if they are careful
8247                */
8248         rcu_assign_pointer(p->replacement, NULL);
8249
8250         if (!err)
8251             err = log_modify(conf, tmp, true);
8252     }
8253
8254     clear_bit(WantReplacement, &rdev->flags);
8255 abort:
8256
8257     print_raid5_conf(conf);
8258     return err;
8259 }
8260
8261 static int raid5_add_disk(struct mddev *mddev, struct md_rdev *rdev)
8262 {
8263     struct r5conf *conf = mddev->private;
8264     int ret, err = -EEXIST;
8265     int disk;
8266     struct disk_info *p;
8267     struct md_rdev *tmp;
8268     int first = 0;
8269     int last = conf->raid_disks - 1;
8270
8271     if (test_bit(Journal, &rdev->flags)) {
8272         if (conf->log)
8273             return -EBUSY;
8274
8275         rdev->raid_disk = 0;
8276         /*
8277          * The array is in readonly mode if journal is missing, so no
8278          * write requests running. We should be safe
8279          */
8280         ret = log_init(conf, rdev, false);
8281         if (ret)
8282             return ret;
8283
8284         ret = r5l_start(conf->log);
8285         if (ret)
8286             return ret;
8287
8288         return 0;
8289     }
8290     if (mddev->recovery_disabled == conf->recovery_disabled)
8291         return -EBUSY;
8292
8293     if (rdev->saved_raid_disk < 0 && has_failed(conf))
8294         /* no point adding a device */
8295         return -EINVAL;
8296
8297     if (rdev->raid_disk >= 0)
8298         first = last = rdev->raid_disk;
8299
8300     /*
8301      * find the disk ... but prefer rdev->saved_raid_disk
8302      * if possible.
8303      */
8304     if (rdev->saved_raid_disk >= first &&
8305         rdev->saved_raid_disk <= last &&
8306         conf->disks[rdev->saved_raid_disk].rdev == NULL)
8307         first = rdev->saved_raid_disk;
8308
8309     for (disk = first; disk <= last; disk++) {
8310         p = conf->disks + disk;
8311         if (p->rdev == NULL) {
8312             clear_bit(In_sync, &rdev->flags);
8313             rdev->raid_disk = disk;
8314             if (rdev->saved_raid_disk != disk)
8315                 conf->fullsync = 1;
8316             rcu_assign_pointer(p->rdev, rdev);
8317
8318             err = log_modify(conf, rdev, true);
8319
8320             goto out;
8321         }
8322     }
8323     for (disk = first; disk <= last; disk++) {
8324         p = conf->disks + disk;
8325         tmp = rdev_mdlock_deref(mddev, p->rdev);
8326         if (test_bit(WantReplacement, &tmp->flags) &&
8327             p->replacement == NULL) {
8328             clear_bit(In_sync, &rdev->flags);
8329             set_bit(Replacement, &rdev->flags);
8330             rdev->raid_disk = disk;
8331             err = 0;
8332             conf->fullsync = 1;
8333             rcu_assign_pointer(p->replacement, rdev);
8334             break;
8335         }
8336     }
8337 out:
8338     print_raid5_conf(conf);
8339     return err;
8340 }
8341
8342 static int raid5_resize(struct mddev *mddev, sector_t sectors)
8343 {
8344     /* no resync is happening, and there is enough space
8345      * on all devices, so we can resize.
8346      * We need to make sure resync covers any new space.
8347      * If the array is shrinking we should possibly wait until
8348      * any io in the removed space completes, but it hardly seems
8349      * worth it.
8350      */
8351     sector_t newsize;
8352     struct r5conf *conf = mddev->private;
8353
8354     if (raid5_has_log(conf) || raid5_has_ppl(conf))
8355         return -EINVAL;
8356     sectors &= ~((sector_t)conf->chunk_sectors - 1);
8357     newsize = raid5_size(mddev, sectors, mddev->raid_disks);
8358     if (mddev->external_size &&
8359         mddev->array_sectors > newsize)
8360         return -EINVAL;
8361     if (mddev->bitmap) {
8362         int ret = md_bitmap_resize(mddev->bitmap, sectors, 0, 0);
8363         if (ret)
8364             return ret;
8365     }
8366     md_set_array_sectors(mddev, newsize);
8367     if (sectors > mddev->dev_sectors &&
8368         mddev->recovery_cp > mddev->dev_sectors) {
8369         mddev->recovery_cp = mddev->dev_sectors;
8370         set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
8371     }
8372     mddev->dev_sectors = sectors;
8373     mddev->resync_max_sectors = sectors;
8374     return 0;
8375 }
8376
8377 static int check_stripe_cache(struct mddev *mddev)
8378 {
8379     /* Can only proceed if there are plenty of stripe_heads.
8380      * We need a minimum of one full stripe,, and for sensible progress
8381      * it is best to have about 4 times that.
8382      * If we require 4 times, then the default 256 4K stripe_heads will
8383      * allow for chunk sizes up to 256K, which is probably OK.
8384      * If the chunk size is greater, user-space should request more
8385      * stripe_heads first.
8386      */
8387     struct r5conf *conf = mddev->private;
8388     if (((mddev->chunk_sectors << 9) / RAID5_STRIPE_SIZE(conf)) * 4
8389         > conf->min_nr_stripes ||
8390         ((mddev->new_chunk_sectors << 9) / RAID5_STRIPE_SIZE(conf)) * 4
8391         > conf->min_nr_stripes) {
8392         pr_warn("md/raid:%s: reshape: not enough stripes.  Needed %lu\n",
8393             mdname(mddev),
8394             ((max(mddev->chunk_sectors, mddev->new_chunk_sectors) << 9)
8395              / RAID5_STRIPE_SIZE(conf))*4);
8396         return 0;
8397     }
8398     return 1;
8399 }
8400
8401 static int check_reshape(struct mddev *mddev)
8402 {
8403     struct r5conf *conf = mddev->private;
8404
8405     if (raid5_has_log(conf) || raid5_has_ppl(conf))
8406         return -EINVAL;
8407     if (mddev->delta_disks == 0 &&
8408         mddev->new_layout == mddev->layout &&
8409         mddev->new_chunk_sectors == mddev->chunk_sectors)
8410         return 0; /* nothing to do */
8411     if (has_failed(conf))
8412         return -EINVAL;
8413     if (mddev->delta_disks < 0 && mddev->reshape_position == MaxSector) {
8414         /* We might be able to shrink, but the devices must
8415          * be made bigger first.
8416          * For raid6, 4 is the minimum size.
8417          * Otherwise 2 is the minimum
8418          */
8419         int min = 2;
8420         if (mddev->level == 6)
8421             min = 4;
8422         if (mddev->raid_disks + mddev->delta_disks < min)
8423             return -EINVAL;
8424     }
8425
8426     if (!check_stripe_cache(mddev))
8427         return -ENOSPC;
8428
8429     if (mddev->new_chunk_sectors > mddev->chunk_sectors ||
8430         mddev->delta_disks > 0)
8431         if (resize_chunks(conf,
8432                   conf->previous_raid_disks
8433                   + max(0, mddev->delta_disks),
8434                   max(mddev->new_chunk_sectors,
8435                       mddev->chunk_sectors)
8436                 ) < 0)
8437             return -ENOMEM;
8438
8439     if (conf->previous_raid_disks + mddev->delta_disks <= conf->pool_size)
8440         return 0; /* never bother to shrink */
8441     return resize_stripes(conf, (conf->previous_raid_disks
8442                      + mddev->delta_disks));
8443 }
8444
8445 static int raid5_start_reshape(struct mddev *mddev)
8446 {
8447     struct r5conf *conf = mddev->private;
8448     struct md_rdev *rdev;
8449     int spares = 0;
8450     unsigned long flags;
8451
8452     if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
8453         return -EBUSY;
8454
8455     if (!check_stripe_cache(mddev))
8456         return -ENOSPC;
8457
8458     if (has_failed(conf))
8459         return -EINVAL;
8460
8461     rdev_for_each(rdev, mddev) {
8462         if (!test_bit(In_sync, &rdev->flags)
8463             && !test_bit(Faulty, &rdev->flags))
8464             spares++;
8465     }
8466
8467     if (spares - mddev->degraded < mddev->delta_disks - conf->max_degraded)
8468         /* Not enough devices even to make a degraded array
8469          * of that size
8470          */
8471         return -EINVAL;
8472
8473     /* Refuse to reduce size of the array.  Any reductions in
8474      * array size must be through explicit setting of array_size
8475      * attribute.
8476      */
8477     if (raid5_size(mddev, 0, conf->raid_disks + mddev->delta_disks)
8478         < mddev->array_sectors) {
8479         pr_warn("md/raid:%s: array size must be reduced before number of disks\n",
8480             mdname(mddev));
8481         return -EINVAL;
8482     }
8483
8484     atomic_set(&conf->reshape_stripes, 0);
8485     spin_lock_irq(&conf->device_lock);
8486     write_seqcount_begin(&conf->gen_lock);
8487     conf->previous_raid_disks = conf->raid_disks;
8488     conf->raid_disks += mddev->delta_disks;
8489     conf->prev_chunk_sectors = conf->chunk_sectors;
8490     conf->chunk_sectors = mddev->new_chunk_sectors;
8491     conf->prev_algo = conf->algorithm;
8492     conf->algorithm = mddev->new_layout;
8493     conf->generation++;
8494     /* Code that selects data_offset needs to see the generation update
8495      * if reshape_progress has been set - so a memory barrier needed.
8496      */
8497     smp_mb();
8498     if (mddev->reshape_backwards)
8499         conf->reshape_progress = raid5_size(mddev, 0, 0);
8500     else
8501         conf->reshape_progress = 0;
8502     conf->reshape_safe = conf->reshape_progress;
8503     write_seqcount_end(&conf->gen_lock);
8504     spin_unlock_irq(&conf->device_lock);
8505
8506     /* Now make sure any requests that proceeded on the assumption
8507      * the reshape wasn't running - like Discard or Read - have
8508      * completed.
8509      */
8510     mddev_suspend(mddev);
8511     mddev_resume(mddev);
8512
8513     /* Add some new drives, as many as will fit.
8514      * We know there are enough to make the newly sized array work.
8515      * Don't add devices if we are reducing the number of
8516      * devices in the array.  This is because it is not possible
8517      * to correctly record the "partially reconstructed" state of
8518      * such devices during the reshape and confusion could result.
8519      */
8520     if (mddev->delta_disks >= 0) {
8521         rdev_for_each(rdev, mddev)
8522             if (rdev->raid_disk < 0 &&
8523                 !test_bit(Faulty, &rdev->flags)) {
8524                 if (raid5_add_disk(mddev, rdev) == 0) {
8525                     if (rdev->raid_disk
8526                         >= conf->previous_raid_disks)
8527                         set_bit(In_sync, &rdev->flags);
8528                     else
8529                         rdev->recovery_offset = 0;
8530
8531                     /* Failure here is OK */
8532                     sysfs_link_rdev(mddev, rdev);
8533                 }
8534             } else if (rdev->raid_disk >= conf->previous_raid_disks
8535                    && !test_bit(Faulty, &rdev->flags)) {
8536                 /* This is a spare that was manually added */
8537                 set_bit(In_sync, &rdev->flags);
8538             }
8539
8540         /* When a reshape changes the number of devices,
8541          * ->degraded is measured against the larger of the
8542          * pre and post number of devices.
8543          */
8544         spin_lock_irqsave(&conf->device_lock, flags);
8545         mddev->degraded = raid5_calc_degraded(conf);
8546         spin_unlock_irqrestore(&conf->device_lock, flags);
8547     }
8548     mddev->raid_disks = conf->raid_disks;
8549     mddev->reshape_position = conf->reshape_progress;
8550     set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
8551
8552     clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
8553     clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
8554     clear_bit(MD_RECOVERY_DONE, &mddev->recovery);
8555     set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
8556     set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
8557     mddev->sync_thread = md_register_thread(md_do_sync, mddev,
8558                         "reshape");
8559     if (!mddev->sync_thread) {
8560         mddev->recovery = 0;
8561         spin_lock_irq(&conf->device_lock);
8562         write_seqcount_begin(&conf->gen_lock);
8563         mddev->raid_disks = conf->raid_disks = conf->previous_raid_disks;
8564         mddev->new_chunk_sectors =
8565             conf->chunk_sectors = conf->prev_chunk_sectors;
8566         mddev->new_layout = conf->algorithm = conf->prev_algo;
8567         rdev_for_each(rdev, mddev)
8568             rdev->new_data_offset = rdev->data_offset;
8569         smp_wmb();
8570         conf->generation --;
8571         conf->reshape_progress = MaxSector;
8572         mddev->reshape_position = MaxSector;
8573         write_seqcount_end(&conf->gen_lock);
8574         spin_unlock_irq(&conf->device_lock);
8575         return -EAGAIN;
8576     }
8577     conf->reshape_checkpoint = jiffies;
8578     md_wakeup_thread(mddev->sync_thread);
8579     md_new_event();
8580     return 0;
8581 }
8582
8583 /* This is called from the reshape thread and should make any
8584  * changes needed in 'conf'
8585  */
8586 static void end_reshape(struct r5conf *conf)
8587 {
8588
8589     if (!test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery)) {
8590         struct md_rdev *rdev;
8591
8592         spin_lock_irq(&conf->device_lock);
8593         conf->previous_raid_disks = conf->raid_disks;
8594         md_finish_reshape(conf->mddev);
8595         smp_wmb();
8596         conf->reshape_progress = MaxSector;
8597         conf->mddev->reshape_position = MaxSector;
8598         rdev_for_each(rdev, conf->mddev)
8599             if (rdev->raid_disk >= 0 &&
8600                 !test_bit(Journal, &rdev->flags) &&
8601                 !test_bit(In_sync, &rdev->flags))
8602                 rdev->recovery_offset = MaxSector;
8603         spin_unlock_irq(&conf->device_lock);
8604         wake_up(&conf->wait_for_overlap);
8605
8606         if (conf->mddev->queue)
8607             raid5_set_io_opt(conf);
8608     }
8609 }
8610
8611 /* This is called from the raid5d thread with mddev_lock held.
8612  * It makes config changes to the device.
8613  */
8614 static void raid5_finish_reshape(struct mddev *mddev)
8615 {
8616     struct r5conf *conf = mddev->private;
8617     struct md_rdev *rdev;
8618
8619     if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
8620
8621         if (mddev->delta_disks <= 0) {
8622             int d;
8623             spin_lock_irq(&conf->device_lock);
8624             mddev->degraded = raid5_calc_degraded(conf);
8625             spin_unlock_irq(&conf->device_lock);
8626             for (d = conf->raid_disks ;
8627                  d < conf->raid_disks - mddev->delta_disks;
8628                  d++) {
8629                 rdev = rdev_mdlock_deref(mddev,
8630                              conf->disks[d].rdev);
8631                 if (rdev)
8632                     clear_bit(In_sync, &rdev->flags);
8633                 rdev = rdev_mdlock_deref(mddev,
8634                         conf->disks[d].replacement);
8635                 if (rdev)
8636                     clear_bit(In_sync, &rdev->flags);
8637             }
8638         }
8639         mddev->layout = conf->algorithm;
8640         mddev->chunk_sectors = conf->chunk_sectors;
8641         mddev->reshape_position = MaxSector;
8642         mddev->delta_disks = 0;
8643         mddev->reshape_backwards = 0;
8644     }
8645 }
8646
8647 static void raid5_quiesce(struct mddev *mddev, int quiesce)
8648 {
8649     struct r5conf *conf = mddev->private;
8650
8651     if (quiesce) {
8652         /* stop all writes */
8653         lock_all_device_hash_locks_irq(conf);
8654         /* '2' tells resync/reshape to pause so that all
8655          * active stripes can drain
8656          */
8657         r5c_flush_cache(conf, INT_MAX);
8658         /* need a memory barrier to make sure read_one_chunk() sees
8659          * quiesce started and reverts to slow (locked) path.
8660          */
8661         smp_store_release(&conf->quiesce, 2);
8662         wait_event_cmd(conf->wait_for_quiescent,
8663                     atomic_read(&conf->active_stripes) == 0 &&
8664                     atomic_read(&conf->active_aligned_reads) == 0,
8665                     unlock_all_device_hash_locks_irq(conf),
8666                     lock_all_device_hash_locks_irq(conf));
8667         conf->quiesce = 1;
8668         unlock_all_device_hash_locks_irq(conf);
8669         /* allow reshape to continue */
8670         wake_up(&conf->wait_for_overlap);
8671     } else {
8672         /* re-enable writes */
8673         lock_all_device_hash_locks_irq(conf);
8674         conf->quiesce = 0;
8675         wake_up(&conf->wait_for_quiescent);
8676         wake_up(&conf->wait_for_overlap);
8677         unlock_all_device_hash_locks_irq(conf);
8678     }
8679     log_quiesce(conf, quiesce);
8680 }
8681
8682 static void *raid45_takeover_raid0(struct mddev *mddev, int level)
8683 {
8684     struct r0conf *raid0_conf = mddev->private;
8685     sector_t sectors;
8686
8687     /* for raid0 takeover only one zone is supported */
8688     if (raid0_conf->nr_strip_zones > 1) {
8689         pr_warn("md/raid:%s: cannot takeover raid0 with more than one zone.\n",
8690             mdname(mddev));
8691         return ERR_PTR(-EINVAL);
8692     }
8693
8694     sectors = raid0_conf->strip_zone[0].zone_end;
8695     sector_div(sectors, raid0_conf->strip_zone[0].nb_dev);
8696     mddev->dev_sectors = sectors;
8697     mddev->new_level = level;
8698     mddev->new_layout = ALGORITHM_PARITY_N;
8699     mddev->new_chunk_sectors = mddev->chunk_sectors;
8700     mddev->raid_disks += 1;
8701     mddev->delta_disks = 1;
8702     /* make sure it will be not marked as dirty */
8703     mddev->recovery_cp = MaxSector;
8704
8705     return setup_conf(mddev);
8706 }
8707
8708 static void *raid5_takeover_raid1(struct mddev *mddev)
8709 {
8710     int chunksect;
8711     void *ret;
8712
8713     if (mddev->raid_disks != 2 ||
8714         mddev->degraded > 1)
8715         return ERR_PTR(-EINVAL);
8716
8717     /* Should check if there are write-behind devices? */
8718
8719     chunksect = 64*2; /* 64K by default */
8720
8721     /* The array must be an exact multiple of chunksize */
8722     while (chunksect && (mddev->array_sectors & (chunksect-1)))
8723         chunksect >>= 1;
8724
8725     if ((chunksect<<9) < RAID5_STRIPE_SIZE((struct r5conf *)mddev->private))
8726         /* array size does not allow a suitable chunk size */
8727         return ERR_PTR(-EINVAL);
8728
8729     mddev->new_level = 5;
8730     mddev->new_layout = ALGORITHM_LEFT_SYMMETRIC;
8731     mddev->new_chunk_sectors = chunksect;
8732
8733     ret = setup_conf(mddev);
8734     if (!IS_ERR(ret))
8735         mddev_clear_unsupported_flags(mddev,
8736             UNSUPPORTED_MDDEV_FLAGS);
8737     return ret;
8738 }
8739
8740 static void *raid5_takeover_raid6(struct mddev *mddev)
8741 {
8742     int new_layout;
8743
8744     switch (mddev->layout) {
8745     case ALGORITHM_LEFT_ASYMMETRIC_6:
8746         new_layout = ALGORITHM_LEFT_ASYMMETRIC;
8747         break;
8748     case ALGORITHM_RIGHT_ASYMMETRIC_6:
8749         new_layout = ALGORITHM_RIGHT_ASYMMETRIC;
8750         break;
8751     case ALGORITHM_LEFT_SYMMETRIC_6:
8752         new_layout = ALGORITHM_LEFT_SYMMETRIC;
8753         break;
8754     case ALGORITHM_RIGHT_SYMMETRIC_6:
8755         new_layout = ALGORITHM_RIGHT_SYMMETRIC;
8756         break;
8757     case ALGORITHM_PARITY_0_6:
8758         new_layout = ALGORITHM_PARITY_0;
8759         break;
8760     case ALGORITHM_PARITY_N:
8761         new_layout = ALGORITHM_PARITY_N;
8762         break;
8763     default:
8764         return ERR_PTR(-EINVAL);
8765     }
8766     mddev->new_level = 5;
8767     mddev->new_layout = new_layout;
8768     mddev->delta_disks = -1;
8769     mddev->raid_disks -= 1;
8770     return setup_conf(mddev);
8771 }
8772
8773 static int raid5_check_reshape(struct mddev *mddev)
8774 {
8775     /* For a 2-drive array, the layout and chunk size can be changed
8776      * immediately as not restriping is needed.
8777      * For larger arrays we record the new value - after validation
8778      * to be used by a reshape pass.
8779      */
8780     struct r5conf *conf = mddev->private;
8781     int new_chunk = mddev->new_chunk_sectors;
8782
8783     if (mddev->new_layout >= 0 && !algorithm_valid_raid5(mddev->new_layout))
8784         return -EINVAL;
8785     if (new_chunk > 0) {
8786         if (!is_power_of_2(new_chunk))
8787             return -EINVAL;
8788         if (new_chunk < (PAGE_SIZE>>9))
8789             return -EINVAL;
8790         if (mddev->array_sectors & (new_chunk-1))
8791             /* not factor of array size */
8792             return -EINVAL;
8793     }
8794
8795     /* They look valid */
8796
8797     if (mddev->raid_disks == 2) {
8798         /* can make the change immediately */
8799         if (mddev->new_layout >= 0) {
8800             conf->algorithm = mddev->new_layout;
8801             mddev->layout = mddev->new_layout;
8802         }
8803         if (new_chunk > 0) {
8804             conf->chunk_sectors = new_chunk ;
8805             mddev->chunk_sectors = new_chunk;
8806         }
8807         set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
8808         md_wakeup_thread(mddev->thread);
8809     }
8810     return check_reshape(mddev);
8811 }
8812
8813 static int raid6_check_reshape(struct mddev *mddev)
8814 {
8815     int new_chunk = mddev->new_chunk_sectors;
8816
8817     if (mddev->new_layout >= 0 && !algorithm_valid_raid6(mddev->new_layout))
8818         return -EINVAL;
8819     if (new_chunk > 0) {
8820         if (!is_power_of_2(new_chunk))
8821             return -EINVAL;
8822         if (new_chunk < (PAGE_SIZE >> 9))
8823             return -EINVAL;
8824         if (mddev->array_sectors & (new_chunk-1))
8825             /* not factor of array size */
8826             return -EINVAL;
8827     }
8828
8829     /* They look valid */
8830     return check_reshape(mddev);
8831 }
8832
8833 static void *raid5_takeover(struct mddev *mddev)
8834 {
8835     /* raid5 can take over:
8836      *  raid0 - if there is only one strip zone - make it a raid4 layout
8837      *  raid1 - if there are two drives.  We need to know the chunk size
8838      *  raid4 - trivial - just use a raid4 layout.
8839      *  raid6 - Providing it is a *_6 layout
8840      */
8841     if (mddev->level == 0)
8842         return raid45_takeover_raid0(mddev, 5);
8843     if (mddev->level == 1)
8844         return raid5_takeover_raid1(mddev);
8845     if (mddev->level == 4) {
8846         mddev->new_layout = ALGORITHM_PARITY_N;
8847         mddev->new_level = 5;
8848         return setup_conf(mddev);
8849     }
8850     if (mddev->level == 6)
8851         return raid5_takeover_raid6(mddev);
8852
8853     return ERR_PTR(-EINVAL);
8854 }
8855
8856 static void *raid4_takeover(struct mddev *mddev)
8857 {
8858     /* raid4 can take over:
8859      *  raid0 - if there is only one strip zone
8860      *  raid5 - if layout is right
8861      */
8862     if (mddev->level == 0)
8863         return raid45_takeover_raid0(mddev, 4);
8864     if (mddev->level == 5 &&
8865         mddev->layout == ALGORITHM_PARITY_N) {
8866         mddev->new_layout = 0;
8867         mddev->new_level = 4;
8868         return setup_conf(mddev);
8869     }
8870     return ERR_PTR(-EINVAL);
8871 }
8872
8873 static struct md_personality raid5_personality;
8874
8875 static void *raid6_takeover(struct mddev *mddev)
8876 {
8877     /* Currently can only take over a raid5.  We map the
8878      * personality to an equivalent raid6 personality
8879      * with the Q block at the end.
8880      */
8881     int new_layout;
8882
8883     if (mddev->pers != &raid5_personality)
8884         return ERR_PTR(-EINVAL);
8885     if (mddev->degraded > 1)
8886         return ERR_PTR(-EINVAL);
8887     if (mddev->raid_disks > 253)
8888         return ERR_PTR(-EINVAL);
8889     if (mddev->raid_disks < 3)
8890         return ERR_PTR(-EINVAL);
8891
8892     switch (mddev->layout) {
8893     case ALGORITHM_LEFT_ASYMMETRIC:
8894         new_layout = ALGORITHM_LEFT_ASYMMETRIC_6;
8895         break;
8896     case ALGORITHM_RIGHT_ASYMMETRIC:
8897         new_layout = ALGORITHM_RIGHT_ASYMMETRIC_6;
8898         break;
8899     case ALGORITHM_LEFT_SYMMETRIC:
8900         new_layout = ALGORITHM_LEFT_SYMMETRIC_6;
8901         break;
8902     case ALGORITHM_RIGHT_SYMMETRIC:
8903         new_layout = ALGORITHM_RIGHT_SYMMETRIC_6;
8904         break;
8905     case ALGORITHM_PARITY_0:
8906         new_layout = ALGORITHM_PARITY_0_6;
8907         break;
8908     case ALGORITHM_PARITY_N:
8909         new_layout = ALGORITHM_PARITY_N;
8910         break;
8911     default:
8912         return ERR_PTR(-EINVAL);
8913     }
8914     mddev->new_level = 6;
8915     mddev->new_layout = new_layout;
8916     mddev->delta_disks = 1;
8917     mddev->raid_disks += 1;
8918     return setup_conf(mddev);
8919 }
8920
8921 static int raid5_change_consistency_policy(struct mddev *mddev, const char *buf)
8922 {
8923     struct r5conf *conf;
8924     int err;
8925
8926     err = mddev_lock(mddev);
8927     if (err)
8928         return err;
8929     conf = mddev->private;
8930     if (!conf) {
8931         mddev_unlock(mddev);
8932         return -ENODEV;
8933     }
8934
8935     if (strncmp(buf, "ppl", 3) == 0) {
8936         /* ppl only works with RAID 5 */
8937         if (!raid5_has_ppl(conf) && conf->level == 5) {
8938             err = log_init(conf, NULL, true);
8939             if (!err) {
8940                 err = resize_stripes(conf, conf->pool_size);
8941                 if (err) {
8942                     mddev_suspend(mddev);
8943                     log_exit(conf);
8944                     mddev_resume(mddev);
8945                 }
8946             }
8947         } else
8948             err = -EINVAL;
8949     } else if (strncmp(buf, "resync", 6) == 0) {
8950         if (raid5_has_ppl(conf)) {
8951             mddev_suspend(mddev);
8952             log_exit(conf);
8953             mddev_resume(mddev);
8954             err = resize_stripes(conf, conf->pool_size);
8955         } else if (test_bit(MD_HAS_JOURNAL, &conf->mddev->flags) &&
8956                r5l_log_disk_error(conf)) {
8957             bool journal_dev_exists = false;
8958             struct md_rdev *rdev;
8959
8960             rdev_for_each(rdev, mddev)
8961                 if (test_bit(Journal, &rdev->flags)) {
8962                     journal_dev_exists = true;
8963                     break;
8964                 }
8965
8966             if (!journal_dev_exists) {
8967                 mddev_suspend(mddev);
8968                 clear_bit(MD_HAS_JOURNAL, &mddev->flags);
8969                 mddev_resume(mddev);
8970             } else  /* need remove journal device first */
8971                 err = -EBUSY;
8972         } else
8973             err = -EINVAL;
8974     } else {
8975         err = -EINVAL;
8976     }
8977
8978     if (!err)
8979         md_update_sb(mddev, 1);
8980
8981     mddev_unlock(mddev);
8982
8983     return err;
8984 }
8985
8986 static int raid5_start(struct mddev *mddev)
8987 {
8988     struct r5conf *conf = mddev->private;
8989
8990     return r5l_start(conf->log);
8991 }
8992
8993 static struct md_personality raid6_personality =
8994 {
8995     .name       = "raid6",
8996     .level      = 6,
8997     .owner      = THIS_MODULE,
8998     .make_request   = raid5_make_request,
8999     .run        = raid5_run,
9000     .start      = raid5_start,
9001     .free       = raid5_free,
9002     .status     = raid5_status,
9003     .error_handler  = raid5_error,
9004     .hot_add_disk   = raid5_add_disk,
9005     .hot_remove_disk= raid5_remove_disk,
9006     .spare_active   = raid5_spare_active,
9007     .sync_request   = raid5_sync_request,
9008     .resize     = raid5_resize,
9009     .size       = raid5_size,
9010     .check_reshape  = raid6_check_reshape,
9011     .start_reshape  = raid5_start_reshape,
9012     .finish_reshape = raid5_finish_reshape,
9013     .quiesce    = raid5_quiesce,
9014     .takeover   = raid6_takeover,
9015     .change_consistency_policy = raid5_change_consistency_policy,
9016 };
9017 static struct md_personality raid5_personality =
9018 {
9019     .name       = "raid5",
9020     .level      = 5,
9021     .owner      = THIS_MODULE,
9022     .make_request   = raid5_make_request,
9023     .run        = raid5_run,
9024     .start      = raid5_start,
9025     .free       = raid5_free,
9026     .status     = raid5_status,
9027     .error_handler  = raid5_error,
9028     .hot_add_disk   = raid5_add_disk,
9029     .hot_remove_disk= raid5_remove_disk,
9030     .spare_active   = raid5_spare_active,
9031     .sync_request   = raid5_sync_request,
9032     .resize     = raid5_resize,
9033     .size       = raid5_size,
9034     .check_reshape  = raid5_check_reshape,
9035     .start_reshape  = raid5_start_reshape,
9036     .finish_reshape = raid5_finish_reshape,
9037     .quiesce    = raid5_quiesce,
9038     .takeover   = raid5_takeover,
9039     .change_consistency_policy = raid5_change_consistency_policy,
9040 };
9041
9042 static struct md_personality raid4_personality =
9043 {
9044     .name       = "raid4",
9045     .level      = 4,
9046     .owner      = THIS_MODULE,
9047     .make_request   = raid5_make_request,
9048     .run        = raid5_run,
9049     .start      = raid5_start,
9050     .free       = raid5_free,
9051     .status     = raid5_status,
9052     .error_handler  = raid5_error,
9053     .hot_add_disk   = raid5_add_disk,
9054     .hot_remove_disk= raid5_remove_disk,
9055     .spare_active   = raid5_spare_active,
9056     .sync_request   = raid5_sync_request,
9057     .resize     = raid5_resize,
9058     .size       = raid5_size,
9059     .check_reshape  = raid5_check_reshape,
9060     .start_reshape  = raid5_start_reshape,
9061     .finish_reshape = raid5_finish_reshape,
9062     .quiesce    = raid5_quiesce,
9063     .takeover   = raid4_takeover,
9064     .change_consistency_policy = raid5_change_consistency_policy,
9065 };
9066
9067 static int __init raid5_init(void)
9068 {
9069     int ret;
9070
9071     raid5_wq = alloc_workqueue("raid5wq",
9072         WQ_UNBOUND|WQ_MEM_RECLAIM|WQ_CPU_INTENSIVE|WQ_SYSFS, 0);
9073     if (!raid5_wq)
9074         return -ENOMEM;
9075
9076     ret = cpuhp_setup_state_multi(CPUHP_MD_RAID5_PREPARE,
9077                       "md/raid5:prepare",
9078                       raid456_cpu_up_prepare,
9079                       raid456_cpu_dead);
9080     if (ret) {
9081         destroy_workqueue(raid5_wq);
9082         return ret;
9083     }
9084     register_md_personality(&raid6_personality);
9085     register_md_personality(&raid5_personality);
9086     register_md_personality(&raid4_personality);
9087     return 0;
9088 }
9089
9090 static void raid5_exit(void)
9091 {
9092     unregister_md_personality(&raid6_personality);
9093     unregister_md_personality(&raid5_personality);
9094     unregister_md_personality(&raid4_personality);
9095     cpuhp_remove_multi_state(CPUHP_MD_RAID5_PREPARE);
9096     destroy_workqueue(raid5_wq);
9097 }
9098
9099 module_init(raid5_init);
9100 module_exit(raid5_exit);
9101 MODULE_LICENSE("GPL");
9102 MODULE_DESCRIPTION("RAID4/5/6 (striping with parity) personality for MD");
9103 MODULE_ALIAS("md-personality-4"); /* RAID5 */
9104 MODULE_ALIAS("md-raid5");
9105 MODULE_ALIAS("md-raid4");
9106 MODULE_ALIAS("md-level-5");
9107 MODULE_ALIAS("md-level-4");
9108 MODULE_ALIAS("md-personality-8"); /* RAID6 */
9109 MODULE_ALIAS("md-raid6");
9110 MODULE_ALIAS("md-level-6");
9111
9112 /* This used to be two separate modules, they were: */
9113 MODULE_ALIAS("raid5");
9114 MODULE_ALIAS("raid6");