OSCL-LXR linux-6.0.1/​drivers/​block/​drbd/​drbd_actlog.c	Source navigation Diff markup Identifier search General search
	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
    drbd_actlog.c
 
    This file is part of DRBD by Philipp Reisner and Lars Ellenberg.
 
    Copyright (C) 2003-2008, LINBIT Information Technologies GmbH.
    Copyright (C) 2003-2008, Philipp Reisner <philipp.reisner@linbit.com>.
    Copyright (C) 2003-2008, Lars Ellenberg <lars.ellenberg@linbit.com>.
 
 
  */
 
 #include <linux/slab.h>
 #include <linux/crc32c.h>
 #include <linux/drbd.h>
 #include <linux/drbd_limits.h>
 #include "drbd_int.h"
 
 
 enum al_transaction_types {
     AL_TR_UPDATE = 0,
     AL_TR_INITIALIZED = 0xffff
 };
 /* all fields on disc in big endian */
 struct __packed al_transaction_on_disk {
     /* don't we all like magic */
     __be32  magic;
 
     /* to identify the most recent transaction block
      * in the on disk ring buffer */
     __be32  tr_number;
 
     /* checksum on the full 4k block, with this field set to 0. */
     __be32  crc32c;
 
     /* type of transaction, special transaction types like:
      * purge-all, set-all-idle, set-all-active, ... to-be-defined
      * see also enum al_transaction_types */
     __be16  transaction_type;
 
     /* we currently allow only a few thousand extents,
      * so 16bit will be enough for the slot number. */
 
     /* how many updates in this transaction */
     __be16  n_updates;
 
     /* maximum slot number, "al-extents" in drbd.conf speak.
      * Having this in each transaction should make reconfiguration
      * of that parameter easier. */
     __be16  context_size;
 
     /* slot number the context starts with */
     __be16  context_start_slot_nr;
 
     /* Some reserved bytes.  Expected usage is a 64bit counter of
      * sectors-written since device creation, and other data generation tag
      * supporting usage */
     __be32  __reserved[4];
 
     /* --- 36 byte used --- */
 
     /* Reserve space for up to AL_UPDATES_PER_TRANSACTION changes
      * in one transaction, then use the remaining byte in the 4k block for
      * context information.  "Flexible" number of updates per transaction
      * does not help, as we have to account for the case when all update
      * slots are used anyways, so it would only complicate code without
      * additional benefit.
      */
     __be16  update_slot_nr[AL_UPDATES_PER_TRANSACTION];
 
     /* but the extent number is 32bit, which at an extent size of 4 MiB
      * allows to cover device sizes of up to 2**54 Byte (16 PiB) */
     __be32  update_extent_nr[AL_UPDATES_PER_TRANSACTION];
 
     /* --- 420 bytes used (36 + 64*6) --- */
 
     /* 4096 - 420 = 3676 = 919 * 4 */
     __be32  context[AL_CONTEXT_PER_TRANSACTION];
 };
 
 void *drbd_md_get_buffer(struct drbd_device *device, const char *intent)
 {
     int r;
 
     wait_event(device->misc_wait,
            (r = atomic_cmpxchg(&device->md_io.in_use, 0, 1)) == 0 ||
            device->state.disk <= D_FAILED);
 
     if (r)
         return NULL;
 
     device->md_io.current_use = intent;
     device->md_io.start_jif = jiffies;
     device->md_io.submit_jif = device->md_io.start_jif - 1;
     return page_address(device->md_io.page);
 }
 
 void drbd_md_put_buffer(struct drbd_device *device)
 {
     if (atomic_dec_and_test(&device->md_io.in_use))
         wake_up(&device->misc_wait);
 }
 
 void wait_until_done_or_force_detached(struct drbd_device *device, struct drbd_backing_dev *bdev,
                      unsigned int *done)
 {
     long dt;
 
     rcu_read_lock();
     dt = rcu_dereference(bdev->disk_conf)->disk_timeout;
     rcu_read_unlock();
     dt = dt * HZ / 10;
     if (dt == 0)
         dt = MAX_SCHEDULE_TIMEOUT;
 
     dt = wait_event_timeout(device->misc_wait,
             *done || test_bit(FORCE_DETACH, &device->flags), dt);
     if (dt == 0) {
         drbd_err(device, "meta-data IO operation timed out\n");
         drbd_chk_io_error(device, 1, DRBD_FORCE_DETACH);
     }
 }
 
 static int _drbd_md_sync_page_io(struct drbd_device *device,
                  struct drbd_backing_dev *bdev,
                  sector_t sector, enum req_op op)
 {
     struct bio *bio;
     /* we do all our meta data IO in aligned 4k blocks. */
     const int size = 4096;
     int err;
     blk_opf_t op_flags = 0;
 
     device->md_io.done = 0;
     device->md_io.error = -ENODEV;
 
     if ((op == REQ_OP_WRITE) && !test_bit(MD_NO_FUA, &device->flags))
         op_flags |= REQ_FUA | REQ_PREFLUSH;
     op_flags |= REQ_SYNC;
 
     bio = bio_alloc_bioset(bdev->md_bdev, 1, op | op_flags, GFP_NOIO,
                    &drbd_md_io_bio_set);
     bio->bi_iter.bi_sector = sector;
     err = -EIO;
     if (bio_add_page(bio, device->md_io.page, size, 0) != size)
         goto out;
     bio->bi_private = device;
     bio->bi_end_io = drbd_md_endio;
 
     if (op != REQ_OP_WRITE && device->state.disk == D_DISKLESS && device->ldev == NULL)
         /* special case, drbd_md_read() during drbd_adm_attach(): no get_ldev */
         ;
     else if (!get_ldev_if_state(device, D_ATTACHING)) {
         /* Corresponding put_ldev in drbd_md_endio() */
         drbd_err(device, "ASSERT FAILED: get_ldev_if_state() == 1 in _drbd_md_sync_page_io()\n");
         err = -ENODEV;
         goto out;
     }
 
     bio_get(bio); /* one bio_put() is in the completion handler */
     atomic_inc(&device->md_io.in_use); /* drbd_md_put_buffer() is in the completion handler */
     device->md_io.submit_jif = jiffies;
     if (drbd_insert_fault(device, (op == REQ_OP_WRITE) ? DRBD_FAULT_MD_WR : DRBD_FAULT_MD_RD))
         bio_io_error(bio);
     else
         submit_bio(bio);
     wait_until_done_or_force_detached(device, bdev, &device->md_io.done);
     if (!bio->bi_status)
         err = device->md_io.error;
 
  out:
     bio_put(bio);
     return err;
 }
 
 int drbd_md_sync_page_io(struct drbd_device *device, struct drbd_backing_dev *bdev,
              sector_t sector, enum req_op op)
 {
     int err;
     D_ASSERT(device, atomic_read(&device->md_io.in_use) == 1);
 
     BUG_ON(!bdev->md_bdev);
 
     dynamic_drbd_dbg(device, "meta_data io: %s [%d]:%s(,%llus,%s) %pS\n",
          current->comm, current->pid, __func__,
          (unsigned long long)sector, (op == REQ_OP_WRITE) ? "WRITE" : "READ",
          (void*)_RET_IP_ );
 
     if (sector < drbd_md_first_sector(bdev) ||
         sector + 7 > drbd_md_last_sector(bdev))
         drbd_alert(device, "%s [%d]:%s(,%llus,%s) out of range md access!\n",
              current->comm, current->pid, __func__,
              (unsigned long long)sector,
              (op == REQ_OP_WRITE) ? "WRITE" : "READ");
 
     err = _drbd_md_sync_page_io(device, bdev, sector, op);
     if (err) {
         drbd_err(device, "drbd_md_sync_page_io(,%llus,%s) failed with error %d\n",
             (unsigned long long)sector,
             (op == REQ_OP_WRITE) ? "WRITE" : "READ", err);
     }
     return err;
 }
 
 static struct bm_extent *find_active_resync_extent(struct drbd_device *device, unsigned int enr)
 {
     struct lc_element *tmp;
     tmp = lc_find(device->resync, enr/AL_EXT_PER_BM_SECT);
     if (unlikely(tmp != NULL)) {
         struct bm_extent  *bm_ext = lc_entry(tmp, struct bm_extent, lce);
         if (test_bit(BME_NO_WRITES, &bm_ext->flags))
             return bm_ext;
     }
     return NULL;
 }
 
 static struct lc_element *_al_get(struct drbd_device *device, unsigned int enr, bool nonblock)
 {
     struct lc_element *al_ext;
     struct bm_extent *bm_ext;
     int wake;
 
     spin_lock_irq(&device->al_lock);
     bm_ext = find_active_resync_extent(device, enr);
     if (bm_ext) {
         wake = !test_and_set_bit(BME_PRIORITY, &bm_ext->flags);
         spin_unlock_irq(&device->al_lock);
         if (wake)
             wake_up(&device->al_wait);
         return NULL;
     }
     if (nonblock)
         al_ext = lc_try_get(device->act_log, enr);
     else
         al_ext = lc_get(device->act_log, enr);
     spin_unlock_irq(&device->al_lock);
     return al_ext;
 }
 
 bool drbd_al_begin_io_fastpath(struct drbd_device *device, struct drbd_interval *i)
 {
     /* for bios crossing activity log extent boundaries,
      * we may need to activate two extents in one go */
     unsigned first = i->sector >> (AL_EXTENT_SHIFT-9);
     unsigned last = i->size == 0 ? first : (i->sector + (i->size >> 9) - 1) >> (AL_EXTENT_SHIFT-9);
 
     D_ASSERT(device, first <= last);
     D_ASSERT(device, atomic_read(&device->local_cnt) > 0);
 
     /* FIXME figure out a fast path for bios crossing AL extent boundaries */
     if (first != last)
         return false;
 
     return _al_get(device, first, true);
 }
 
 bool drbd_al_begin_io_prepare(struct drbd_device *device, struct drbd_interval *i)
 {
     /* for bios crossing activity log extent boundaries,
      * we may need to activate two extents in one go */
     unsigned first = i->sector >> (AL_EXTENT_SHIFT-9);
     unsigned last = i->size == 0 ? first : (i->sector + (i->size >> 9) - 1) >> (AL_EXTENT_SHIFT-9);
     unsigned enr;
     bool need_transaction = false;
 
     D_ASSERT(device, first <= last);
     D_ASSERT(device, atomic_read(&device->local_cnt) > 0);
 
     for (enr = first; enr <= last; enr++) {
         struct lc_element *al_ext;
         wait_event(device->al_wait,
                 (al_ext = _al_get(device, enr, false)) != NULL);
         if (al_ext->lc_number != enr)
             need_transaction = true;
     }
     return need_transaction;
 }
 
 #if (PAGE_SHIFT + 3) < (AL_EXTENT_SHIFT - BM_BLOCK_SHIFT)
 /* Currently BM_BLOCK_SHIFT, BM_EXT_SHIFT and AL_EXTENT_SHIFT
  * are still coupled, or assume too much about their relation.
  * Code below will not work if this is violated.
  * Will be cleaned up with some followup patch.
  */
 # error FIXME
 #endif
 
 static unsigned int al_extent_to_bm_page(unsigned int al_enr)
 {
     return al_enr >>
         /* bit to page */
         ((PAGE_SHIFT + 3) -
         /* al extent number to bit */
          (AL_EXTENT_SHIFT - BM_BLOCK_SHIFT));
 }
 
 static sector_t al_tr_number_to_on_disk_sector(struct drbd_device *device)
 {
     const unsigned int stripes = device->ldev->md.al_stripes;
     const unsigned int stripe_size_4kB = device->ldev->md.al_stripe_size_4k;
 
     /* transaction number, modulo on-disk ring buffer wrap around */
     unsigned int t = device->al_tr_number % (device->ldev->md.al_size_4k);
 
     /* ... to aligned 4k on disk block */
     t = ((t % stripes) * stripe_size_4kB) + t/stripes;
 
     /* ... to 512 byte sector in activity log */
     t *= 8;
 
     /* ... plus offset to the on disk position */
     return device->ldev->md.md_offset + device->ldev->md.al_offset + t;
 }
 
 static int __al_write_transaction(struct drbd_device *device, struct al_transaction_on_disk *buffer)
 {
     struct lc_element *e;
     sector_t sector;
     int i, mx;
     unsigned extent_nr;
     unsigned crc = 0;
     int err = 0;
 
     memset(buffer, 0, sizeof(*buffer));
     buffer->magic = cpu_to_be32(DRBD_AL_MAGIC);
     buffer->tr_number = cpu_to_be32(device->al_tr_number);
 
     i = 0;
 
     drbd_bm_reset_al_hints(device);
 
     /* Even though no one can start to change this list
      * once we set the LC_LOCKED -- from drbd_al_begin_io(),
      * lc_try_lock_for_transaction() --, someone may still
      * be in the process of changing it. */
     spin_lock_irq(&device->al_lock);
     list_for_each_entry(e, &device->act_log->to_be_changed, list) {
         if (i == AL_UPDATES_PER_TRANSACTION) {
             i++;
             break;
         }
         buffer->update_slot_nr[i] = cpu_to_be16(e->lc_index);
         buffer->update_extent_nr[i] = cpu_to_be32(e->lc_new_number);
         if (e->lc_number != LC_FREE)
             drbd_bm_mark_for_writeout(device,
                     al_extent_to_bm_page(e->lc_number));
         i++;
     }
     spin_unlock_irq(&device->al_lock);
     BUG_ON(i > AL_UPDATES_PER_TRANSACTION);
 
     buffer->n_updates = cpu_to_be16(i);
     for ( ; i < AL_UPDATES_PER_TRANSACTION; i++) {
         buffer->update_slot_nr[i] = cpu_to_be16(-1);
         buffer->update_extent_nr[i] = cpu_to_be32(LC_FREE);
     }
 
     buffer->context_size = cpu_to_be16(device->act_log->nr_elements);
     buffer->context_start_slot_nr = cpu_to_be16(device->al_tr_cycle);
 
     mx = min_t(int, AL_CONTEXT_PER_TRANSACTION,
            device->act_log->nr_elements - device->al_tr_cycle);
     for (i = 0; i < mx; i++) {
         unsigned idx = device->al_tr_cycle + i;
         extent_nr = lc_element_by_index(device->act_log, idx)->lc_number;
         buffer->context[i] = cpu_to_be32(extent_nr);
     }
     for (; i < AL_CONTEXT_PER_TRANSACTION; i++)
         buffer->context[i] = cpu_to_be32(LC_FREE);
 
     device->al_tr_cycle += AL_CONTEXT_PER_TRANSACTION;
     if (device->al_tr_cycle >= device->act_log->nr_elements)
         device->al_tr_cycle = 0;
 
     sector = al_tr_number_to_on_disk_sector(device);
 
     crc = crc32c(0, buffer, 4096);
     buffer->crc32c = cpu_to_be32(crc);
 
     if (drbd_bm_write_hinted(device))
         err = -EIO;
     else {
         bool write_al_updates;
         rcu_read_lock();
         write_al_updates = rcu_dereference(device->ldev->disk_conf)->al_updates;
         rcu_read_unlock();
         if (write_al_updates) {
             if (drbd_md_sync_page_io(device, device->ldev, sector, REQ_OP_WRITE)) {
                 err = -EIO;
                 drbd_chk_io_error(device, 1, DRBD_META_IO_ERROR);
             } else {
                 device->al_tr_number++;
                 device->al_writ_cnt++;
             }
         }
     }
 
     return err;
 }
 
 static int al_write_transaction(struct drbd_device *device)
 {
     struct al_transaction_on_disk *buffer;
     int err;
 
     if (!get_ldev(device)) {
         drbd_err(device, "disk is %s, cannot start al transaction\n",
             drbd_disk_str(device->state.disk));
         return -EIO;
     }
 
     /* The bitmap write may have failed, causing a state change. */
     if (device->state.disk < D_INCONSISTENT) {
         drbd_err(device,
             "disk is %s, cannot write al transaction\n",
             drbd_disk_str(device->state.disk));
         put_ldev(device);
         return -EIO;
     }
 
     /* protects md_io_buffer, al_tr_cycle, ... */
     buffer = drbd_md_get_buffer(device, __func__);
     if (!buffer) {
         drbd_err(device, "disk failed while waiting for md_io buffer\n");
         put_ldev(device);
         return -ENODEV;
     }
 
     err = __al_write_transaction(device, buffer);
 
     drbd_md_put_buffer(device);
     put_ldev(device);
 
     return err;
 }
 
 
 void drbd_al_begin_io_commit(struct drbd_device *device)
 {
     bool locked = false;
 
     /* Serialize multiple transactions.
      * This uses test_and_set_bit, memory barrier is implicit.
      */
     wait_event(device->al_wait,
             device->act_log->pending_changes == 0 ||
             (locked = lc_try_lock_for_transaction(device->act_log)));
 
     if (locked) {
         /* Double check: it may have been committed by someone else,
          * while we have been waiting for the lock. */
         if (device->act_log->pending_changes) {
             bool write_al_updates;
 
             rcu_read_lock();
             write_al_updates = rcu_dereference(device->ldev->disk_conf)->al_updates;
             rcu_read_unlock();
 
             if (write_al_updates)
                 al_write_transaction(device);
             spin_lock_irq(&device->al_lock);
             /* FIXME
             if (err)
                 we need an "lc_cancel" here;
             */
             lc_committed(device->act_log);
             spin_unlock_irq(&device->al_lock);
         }
         lc_unlock(device->act_log);
         wake_up(&device->al_wait);
     }
 }
 
 /*
  * @delegate:   delegate activity log I/O to the worker thread
  */
 void drbd_al_begin_io(struct drbd_device *device, struct drbd_interval *i)
 {
     if (drbd_al_begin_io_prepare(device, i))
         drbd_al_begin_io_commit(device);
 }
 
 int drbd_al_begin_io_nonblock(struct drbd_device *device, struct drbd_interval *i)
 {
     struct lru_cache *al = device->act_log;
     /* for bios crossing activity log extent boundaries,
      * we may need to activate two extents in one go */
     unsigned first = i->sector >> (AL_EXTENT_SHIFT-9);
     unsigned last = i->size == 0 ? first : (i->sector + (i->size >> 9) - 1) >> (AL_EXTENT_SHIFT-9);
     unsigned nr_al_extents;
     unsigned available_update_slots;
     unsigned enr;
 
     D_ASSERT(device, first <= last);
 
     nr_al_extents = 1 + last - first; /* worst case: all touched extends are cold. */
     available_update_slots = min(al->nr_elements - al->used,
                 al->max_pending_changes - al->pending_changes);
 
     /* We want all necessary updates for a given request within the same transaction
      * We could first check how many updates are *actually* needed,
      * and use that instead of the worst-case nr_al_extents */
     if (available_update_slots < nr_al_extents) {
         /* Too many activity log extents are currently "hot".
          *
          * If we have accumulated pending changes already,
          * we made progress.
          *
          * If we cannot get even a single pending change through,
          * stop the fast path until we made some progress,
          * or requests to "cold" extents could be starved. */
         if (!al->pending_changes)
             __set_bit(__LC_STARVING, &device->act_log->flags);
         return -ENOBUFS;
     }
 
     /* Is resync active in this area? */
     for (enr = first; enr <= last; enr++) {
         struct lc_element *tmp;
         tmp = lc_find(device->resync, enr/AL_EXT_PER_BM_SECT);
         if (unlikely(tmp != NULL)) {
             struct bm_extent  *bm_ext = lc_entry(tmp, struct bm_extent, lce);
             if (test_bit(BME_NO_WRITES, &bm_ext->flags)) {
                 if (!test_and_set_bit(BME_PRIORITY, &bm_ext->flags))
                     return -EBUSY;
                 return -EWOULDBLOCK;
             }
         }
     }
 
     /* Checkout the refcounts.
      * Given that we checked for available elements and update slots above,
      * this has to be successful. */
     for (enr = first; enr <= last; enr++) {
         struct lc_element *al_ext;
         al_ext = lc_get_cumulative(device->act_log, enr);
         if (!al_ext)
             drbd_info(device, "LOGIC BUG for enr=%u\n", enr);
     }
     return 0;
 }
 
 void drbd_al_complete_io(struct drbd_device *device, struct drbd_interval *i)
 {
     /* for bios crossing activity log extent boundaries,
      * we may need to activate two extents in one go */
     unsigned first = i->sector >> (AL_EXTENT_SHIFT-9);
     unsigned last = i->size == 0 ? first : (i->sector + (i->size >> 9) - 1) >> (AL_EXTENT_SHIFT-9);
     unsigned enr;
     struct lc_element *extent;
     unsigned long flags;
 
     D_ASSERT(device, first <= last);
     spin_lock_irqsave(&device->al_lock, flags);
 
     for (enr = first; enr <= last; enr++) {
         extent = lc_find(device->act_log, enr);
         if (!extent) {
             drbd_err(device, "al_complete_io() called on inactive extent %u\n", enr);
             continue;
         }
         lc_put(device->act_log, extent);
     }
     spin_unlock_irqrestore(&device->al_lock, flags);
     wake_up(&device->al_wait);
 }
 
 static int _try_lc_del(struct drbd_device *device, struct lc_element *al_ext)
 {
     int rv;
 
     spin_lock_irq(&device->al_lock);
     rv = (al_ext->refcnt == 0);
     if (likely(rv))
         lc_del(device->act_log, al_ext);
     spin_unlock_irq(&device->al_lock);
 
     return rv;
 }
 
 /**
  * drbd_al_shrink() - Removes all active extents form the activity log
  * @device: DRBD device.
  *
  * Removes all active extents form the activity log, waiting until
  * the reference count of each entry dropped to 0 first, of course.
  *
  * You need to lock device->act_log with lc_try_lock() / lc_unlock()
  */
 void drbd_al_shrink(struct drbd_device *device)
 {
     struct lc_element *al_ext;
     int i;
 
     D_ASSERT(device, test_bit(__LC_LOCKED, &device->act_log->flags));
 
     for (i = 0; i < device->act_log->nr_elements; i++) {
         al_ext = lc_element_by_index(device->act_log, i);
         if (al_ext->lc_number == LC_FREE)
             continue;
         wait_event(device->al_wait, _try_lc_del(device, al_ext));
     }
 
     wake_up(&device->al_wait);
 }
 
 int drbd_al_initialize(struct drbd_device *device, void *buffer)
 {
     struct al_transaction_on_disk *al = buffer;
     struct drbd_md *md = &device->ldev->md;
     int al_size_4k = md->al_stripes * md->al_stripe_size_4k;
     int i;
 
     __al_write_transaction(device, al);
     /* There may or may not have been a pending transaction. */
     spin_lock_irq(&device->al_lock);
     lc_committed(device->act_log);
     spin_unlock_irq(&device->al_lock);
 
     /* The rest of the transactions will have an empty "updates" list, and
      * are written out only to provide the context, and to initialize the
      * on-disk ring buffer. */
     for (i = 1; i < al_size_4k; i++) {
         int err = __al_write_transaction(device, al);
         if (err)
             return err;
     }
     return 0;
 }
 
 static const char *drbd_change_sync_fname[] = {
     [RECORD_RS_FAILED] = "drbd_rs_failed_io",
     [SET_IN_SYNC] = "drbd_set_in_sync",
     [SET_OUT_OF_SYNC] = "drbd_set_out_of_sync"
 };
 
 /* ATTENTION. The AL's extents are 4MB each, while the extents in the
  * resync LRU-cache are 16MB each.
  * The caller of this function has to hold an get_ldev() reference.
  *
  * Adjusts the caching members ->rs_left (success) or ->rs_failed (!success),
  * potentially pulling in (and recounting the corresponding bits)
  * this resync extent into the resync extent lru cache.
  *
  * Returns whether all bits have been cleared for this resync extent,
  * precisely: (rs_left <= rs_failed)
  *
  * TODO will be obsoleted once we have a caching lru of the on disk bitmap
  */
 static bool update_rs_extent(struct drbd_device *device,
         unsigned int enr, int count,
         enum update_sync_bits_mode mode)
 {
     struct lc_element *e;
 
     D_ASSERT(device, atomic_read(&device->local_cnt));
 
     /* When setting out-of-sync bits,
      * we don't need it cached (lc_find).
      * But if it is present in the cache,
      * we should update the cached bit count.
      * Otherwise, that extent should be in the resync extent lru cache
      * already -- or we want to pull it in if necessary -- (lc_get),
      * then update and check rs_left and rs_failed. */
     if (mode == SET_OUT_OF_SYNC)
         e = lc_find(device->resync, enr);
     else
         e = lc_get(device->resync, enr);
     if (e) {
         struct bm_extent *ext = lc_entry(e, struct bm_extent, lce);
         if (ext->lce.lc_number == enr) {
             if (mode == SET_IN_SYNC)
                 ext->rs_left -= count;
             else if (mode == SET_OUT_OF_SYNC)
                 ext->rs_left += count;
             else
                 ext->rs_failed += count;
             if (ext->rs_left < ext->rs_failed) {
                 drbd_warn(device, "BAD! enr=%u rs_left=%d "
                     "rs_failed=%d count=%d cstate=%s\n",
                      ext->lce.lc_number, ext->rs_left,
                      ext->rs_failed, count,
                      drbd_conn_str(device->state.conn));
 
                 /* We don't expect to be able to clear more bits
                  * than have been set when we originally counted
                  * the set bits to cache that value in ext->rs_left.
                  * Whatever the reason (disconnect during resync,
                  * delayed local completion of an application write),
                  * try to fix it up by recounting here. */
                 ext->rs_left = drbd_bm_e_weight(device, enr);
             }
         } else {
             /* Normally this element should be in the cache,
              * since drbd_rs_begin_io() pulled it already in.
              *
              * But maybe an application write finished, and we set
              * something outside the resync lru_cache in sync.
              */
             int rs_left = drbd_bm_e_weight(device, enr);
             if (ext->flags != 0) {
                 drbd_warn(device, "changing resync lce: %d[%u;%02lx]"
                      " -> %d[%u;00]\n",
                      ext->lce.lc_number, ext->rs_left,
                      ext->flags, enr, rs_left);
                 ext->flags = 0;
             }
             if (ext->rs_failed) {
                 drbd_warn(device, "Kicking resync_lru element enr=%u "
                      "out with rs_failed=%d\n",
                      ext->lce.lc_number, ext->rs_failed);
             }
             ext->rs_left = rs_left;
             ext->rs_failed = (mode == RECORD_RS_FAILED) ? count : 0;
             /* we don't keep a persistent log of the resync lru,
              * we can commit any change right away. */
             lc_committed(device->resync);
         }
         if (mode != SET_OUT_OF_SYNC)
             lc_put(device->resync, &ext->lce);
         /* no race, we are within the al_lock! */
 
         if (ext->rs_left <= ext->rs_failed) {
             ext->rs_failed = 0;
             return true;
         }
     } else if (mode != SET_OUT_OF_SYNC) {
         /* be quiet if lc_find() did not find it. */
         drbd_err(device, "lc_get() failed! locked=%d/%d flags=%lu\n",
             device->resync_locked,
             device->resync->nr_elements,
             device->resync->flags);
     }
     return false;
 }
 
 void drbd_advance_rs_marks(struct drbd_device *device, unsigned long still_to_go)
 {
     unsigned long now = jiffies;
     unsigned long last = device->rs_mark_time[device->rs_last_mark];
     int next = (device->rs_last_mark + 1) % DRBD_SYNC_MARKS;
     if (time_after_eq(now, last + DRBD_SYNC_MARK_STEP)) {
         if (device->rs_mark_left[device->rs_last_mark] != still_to_go &&
             device->state.conn != C_PAUSED_SYNC_T &&
             device->state.conn != C_PAUSED_SYNC_S) {
             device->rs_mark_time[next] = now;
             device->rs_mark_left[next] = still_to_go;
             device->rs_last_mark = next;
         }
     }
 }
 
 /* It is called lazy update, so don't do write-out too often. */
 static bool lazy_bitmap_update_due(struct drbd_device *device)
 {
     return time_after(jiffies, device->rs_last_bcast + 2*HZ);
 }
 
 static void maybe_schedule_on_disk_bitmap_update(struct drbd_device *device, bool rs_done)
 {
     if (rs_done) {
         struct drbd_connection *connection = first_peer_device(device)->connection;
         if (connection->agreed_pro_version <= 95 ||
             is_sync_target_state(device->state.conn))
             set_bit(RS_DONE, &device->flags);
             /* and also set RS_PROGRESS below */
 
         /* Else: rather wait for explicit notification via receive_state,
          * to avoid uuids-rotated-too-fast causing full resync
          * in next handshake, in case the replication link breaks
          * at the most unfortunate time... */
     } else if (!lazy_bitmap_update_due(device))
         return;
 
     drbd_device_post_work(device, RS_PROGRESS);
 }
 
 static int update_sync_bits(struct drbd_device *device,
         unsigned long sbnr, unsigned long ebnr,
         enum update_sync_bits_mode mode)
 {
     /*
      * We keep a count of set bits per resync-extent in the ->rs_left
      * caching member, so we need to loop and work within the resync extent
      * alignment. Typically this loop will execute exactly once.
      */
     unsigned long flags;
     unsigned long count = 0;
     unsigned int cleared = 0;
     while (sbnr <= ebnr) {
         /* set temporary boundary bit number to last bit number within
          * the resync extent of the current start bit number,
          * but cap at provided end bit number */
         unsigned long tbnr = min(ebnr, sbnr | BM_BLOCKS_PER_BM_EXT_MASK);
         unsigned long c;
 
         if (mode == RECORD_RS_FAILED)
             /* Only called from drbd_rs_failed_io(), bits
              * supposedly still set.  Recount, maybe some
              * of the bits have been successfully cleared
              * by application IO meanwhile.
              */
             c = drbd_bm_count_bits(device, sbnr, tbnr);
         else if (mode == SET_IN_SYNC)
             c = drbd_bm_clear_bits(device, sbnr, tbnr);
         else /* if (mode == SET_OUT_OF_SYNC) */
             c = drbd_bm_set_bits(device, sbnr, tbnr);
 
         if (c) {
             spin_lock_irqsave(&device->al_lock, flags);
             cleared += update_rs_extent(device, BM_BIT_TO_EXT(sbnr), c, mode);
             spin_unlock_irqrestore(&device->al_lock, flags);
             count += c;
         }
         sbnr = tbnr + 1;
     }
     if (count) {
         if (mode == SET_IN_SYNC) {
             unsigned long still_to_go = drbd_bm_total_weight(device);
             bool rs_is_done = (still_to_go <= device->rs_failed);
             drbd_advance_rs_marks(device, still_to_go);
             if (cleared || rs_is_done)
                 maybe_schedule_on_disk_bitmap_update(device, rs_is_done);
         } else if (mode == RECORD_RS_FAILED)
             device->rs_failed += count;
         wake_up(&device->al_wait);
     }
     return count;
 }
 
 static bool plausible_request_size(int size)
 {
     return size > 0
         && size <= DRBD_MAX_BATCH_BIO_SIZE
         && IS_ALIGNED(size, 512);
 }
 
 /* clear the bit corresponding to the piece of storage in question:
  * size byte of data starting from sector.  Only clear a bits of the affected
  * one ore more _aligned_ BM_BLOCK_SIZE blocks.
  *
  * called by worker on C_SYNC_TARGET and receiver on SyncSource.
  *
  */
 int __drbd_change_sync(struct drbd_device *device, sector_t sector, int size,
         enum update_sync_bits_mode mode)
 {
     /* Is called from worker and receiver context _only_ */
     unsigned long sbnr, ebnr, lbnr;
     unsigned long count = 0;
     sector_t esector, nr_sectors;
 
     /* This would be an empty REQ_PREFLUSH, be silent. */
     if ((mode == SET_OUT_OF_SYNC) && size == 0)
         return 0;
 
     if (!plausible_request_size(size)) {
         drbd_err(device, "%s: sector=%llus size=%d nonsense!\n",
                 drbd_change_sync_fname[mode],
                 (unsigned long long)sector, size);
         return 0;
     }
 
     if (!get_ldev(device))
         return 0; /* no disk, no metadata, no bitmap to manipulate bits in */
 
     nr_sectors = get_capacity(device->vdisk);
     esector = sector + (size >> 9) - 1;
 
     if (!expect(sector < nr_sectors))
         goto out;
     if (!expect(esector < nr_sectors))
         esector = nr_sectors - 1;
 
     lbnr = BM_SECT_TO_BIT(nr_sectors-1);
 
     if (mode == SET_IN_SYNC) {
         /* Round up start sector, round down end sector.  We make sure
          * we only clear full, aligned, BM_BLOCK_SIZE blocks. */
         if (unlikely(esector < BM_SECT_PER_BIT-1))
             goto out;
         if (unlikely(esector == (nr_sectors-1)))
             ebnr = lbnr;
         else
             ebnr = BM_SECT_TO_BIT(esector - (BM_SECT_PER_BIT-1));
         sbnr = BM_SECT_TO_BIT(sector + BM_SECT_PER_BIT-1);
     } else {
         /* We set it out of sync, or record resync failure.
          * Should not round anything here. */
         sbnr = BM_SECT_TO_BIT(sector);
         ebnr = BM_SECT_TO_BIT(esector);
     }
 
     count = update_sync_bits(device, sbnr, ebnr, mode);
 out:
     put_ldev(device);
     return count;
 }
 
 static
 struct bm_extent *_bme_get(struct drbd_device *device, unsigned int enr)
 {
     struct lc_element *e;
     struct bm_extent *bm_ext;
     int wakeup = 0;
     unsigned long rs_flags;
 
     spin_lock_irq(&device->al_lock);
     if (device->resync_locked > device->resync->nr_elements/2) {
         spin_unlock_irq(&device->al_lock);
         return NULL;
     }
     e = lc_get(device->resync, enr);
     bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
     if (bm_ext) {
         if (bm_ext->lce.lc_number != enr) {
             bm_ext->rs_left = drbd_bm_e_weight(device, enr);
             bm_ext->rs_failed = 0;
             lc_committed(device->resync);
             wakeup = 1;
         }
         if (bm_ext->lce.refcnt == 1)
             device->resync_locked++;
         set_bit(BME_NO_WRITES, &bm_ext->flags);
     }
     rs_flags = device->resync->flags;
     spin_unlock_irq(&device->al_lock);
     if (wakeup)
         wake_up(&device->al_wait);
 
     if (!bm_ext) {
         if (rs_flags & LC_STARVING)
             drbd_warn(device, "Have to wait for element"
                  " (resync LRU too small?)\n");
         BUG_ON(rs_flags & LC_LOCKED);
     }
 
     return bm_ext;
 }
 
 static int _is_in_al(struct drbd_device *device, unsigned int enr)
 {
     int rv;
 
     spin_lock_irq(&device->al_lock);
     rv = lc_is_used(device->act_log, enr);
     spin_unlock_irq(&device->al_lock);
 
     return rv;
 }
 
 /**
  * drbd_rs_begin_io() - Gets an extent in the resync LRU cache and sets it to BME_LOCKED
  * @device: DRBD device.
  * @sector: The sector number.
  *
  * This functions sleeps on al_wait. Returns 0 on success, -EINTR if interrupted.
  */
 int drbd_rs_begin_io(struct drbd_device *device, sector_t sector)
 {
     unsigned int enr = BM_SECT_TO_EXT(sector);
     struct bm_extent *bm_ext;
     int i, sig;
     bool sa;
 
 retry:
     sig = wait_event_interruptible(device->al_wait,
             (bm_ext = _bme_get(device, enr)));
     if (sig)
         return -EINTR;
 
     if (test_bit(BME_LOCKED, &bm_ext->flags))
         return 0;
 
     /* step aside only while we are above c-min-rate; unless disabled. */
     sa = drbd_rs_c_min_rate_throttle(device);
 
     for (i = 0; i < AL_EXT_PER_BM_SECT; i++) {
         sig = wait_event_interruptible(device->al_wait,
                            !_is_in_al(device, enr * AL_EXT_PER_BM_SECT + i) ||
                            (sa && test_bit(BME_PRIORITY, &bm_ext->flags)));
 
         if (sig || (sa && test_bit(BME_PRIORITY, &bm_ext->flags))) {
             spin_lock_irq(&device->al_lock);
             if (lc_put(device->resync, &bm_ext->lce) == 0) {
                 bm_ext->flags = 0; /* clears BME_NO_WRITES and eventually BME_PRIORITY */
                 device->resync_locked--;
                 wake_up(&device->al_wait);
             }
             spin_unlock_irq(&device->al_lock);
             if (sig)
                 return -EINTR;
             if (schedule_timeout_interruptible(HZ/10))
                 return -EINTR;
             goto retry;
         }
     }
     set_bit(BME_LOCKED, &bm_ext->flags);
     return 0;
 }
 
 /**
  * drbd_try_rs_begin_io() - Gets an extent in the resync LRU cache, does not sleep
  * @device: DRBD device.
  * @sector: The sector number.
  *
  * Gets an extent in the resync LRU cache, sets it to BME_NO_WRITES, then
  * tries to set it to BME_LOCKED. Returns 0 upon success, and -EAGAIN
  * if there is still application IO going on in this area.
  */
 int drbd_try_rs_begin_io(struct drbd_device *device, sector_t sector)
 {
     unsigned int enr = BM_SECT_TO_EXT(sector);
     const unsigned int al_enr = enr*AL_EXT_PER_BM_SECT;
     struct lc_element *e;
     struct bm_extent *bm_ext;
     int i;
     bool throttle = drbd_rs_should_slow_down(device, sector, true);
 
     /* If we need to throttle, a half-locked (only marked BME_NO_WRITES,
      * not yet BME_LOCKED) extent needs to be kicked out explicitly if we
      * need to throttle. There is at most one such half-locked extent,
      * which is remembered in resync_wenr. */
 
     if (throttle && device->resync_wenr != enr)
         return -EAGAIN;
 
     spin_lock_irq(&device->al_lock);
     if (device->resync_wenr != LC_FREE && device->resync_wenr != enr) {
         /* in case you have very heavy scattered io, it may
          * stall the syncer undefined if we give up the ref count
          * when we try again and requeue.
          *
          * if we don't give up the refcount, but the next time
          * we are scheduled this extent has been "synced" by new
          * application writes, we'd miss the lc_put on the
          * extent we keep the refcount on.
          * so we remembered which extent we had to try again, and
          * if the next requested one is something else, we do
          * the lc_put here...
          * we also have to wake_up
          */
         e = lc_find(device->resync, device->resync_wenr);
         bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
         if (bm_ext) {
             D_ASSERT(device, !test_bit(BME_LOCKED, &bm_ext->flags));
             D_ASSERT(device, test_bit(BME_NO_WRITES, &bm_ext->flags));
             clear_bit(BME_NO_WRITES, &bm_ext->flags);
             device->resync_wenr = LC_FREE;
             if (lc_put(device->resync, &bm_ext->lce) == 0) {
                 bm_ext->flags = 0;
                 device->resync_locked--;
             }
             wake_up(&device->al_wait);
         } else {
             drbd_alert(device, "LOGIC BUG\n");
         }
     }
     /* TRY. */
     e = lc_try_get(device->resync, enr);
     bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
     if (bm_ext) {
         if (test_bit(BME_LOCKED, &bm_ext->flags))
             goto proceed;
         if (!test_and_set_bit(BME_NO_WRITES, &bm_ext->flags)) {
             device->resync_locked++;
         } else {
             /* we did set the BME_NO_WRITES,
              * but then could not set BME_LOCKED,
              * so we tried again.
              * drop the extra reference. */
             bm_ext->lce.refcnt--;
             D_ASSERT(device, bm_ext->lce.refcnt > 0);
         }
         goto check_al;
     } else {
         /* do we rather want to try later? */
         if (device->resync_locked > device->resync->nr_elements-3)
             goto try_again;
         /* Do or do not. There is no try. -- Yoda */
         e = lc_get(device->resync, enr);
         bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
         if (!bm_ext) {
             const unsigned long rs_flags = device->resync->flags;
             if (rs_flags & LC_STARVING)
                 drbd_warn(device, "Have to wait for element"
                      " (resync LRU too small?)\n");
             BUG_ON(rs_flags & LC_LOCKED);
             goto try_again;
         }
         if (bm_ext->lce.lc_number != enr) {
             bm_ext->rs_left = drbd_bm_e_weight(device, enr);
             bm_ext->rs_failed = 0;
             lc_committed(device->resync);
             wake_up(&device->al_wait);
             D_ASSERT(device, test_bit(BME_LOCKED, &bm_ext->flags) == 0);
         }
         set_bit(BME_NO_WRITES, &bm_ext->flags);
         D_ASSERT(device, bm_ext->lce.refcnt == 1);
         device->resync_locked++;
         goto check_al;
     }
 check_al:
     for (i = 0; i < AL_EXT_PER_BM_SECT; i++) {
         if (lc_is_used(device->act_log, al_enr+i))
             goto try_again;
     }
     set_bit(BME_LOCKED, &bm_ext->flags);
 proceed:
     device->resync_wenr = LC_FREE;
     spin_unlock_irq(&device->al_lock);
     return 0;
 
 try_again:
     if (bm_ext) {
         if (throttle) {
             D_ASSERT(device, !test_bit(BME_LOCKED, &bm_ext->flags));
             D_ASSERT(device, test_bit(BME_NO_WRITES, &bm_ext->flags));
             clear_bit(BME_NO_WRITES, &bm_ext->flags);
             device->resync_wenr = LC_FREE;
             if (lc_put(device->resync, &bm_ext->lce) == 0) {
                 bm_ext->flags = 0;
                 device->resync_locked--;
             }
             wake_up(&device->al_wait);
         } else
             device->resync_wenr = enr;
     }
     spin_unlock_irq(&device->al_lock);
     return -EAGAIN;
 }
 
 void drbd_rs_complete_io(struct drbd_device *device, sector_t sector)
 {
     unsigned int enr = BM_SECT_TO_EXT(sector);
     struct lc_element *e;
     struct bm_extent *bm_ext;
     unsigned long flags;
 
     spin_lock_irqsave(&device->al_lock, flags);
     e = lc_find(device->resync, enr);
     bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
     if (!bm_ext) {
         spin_unlock_irqrestore(&device->al_lock, flags);
         if (__ratelimit(&drbd_ratelimit_state))
             drbd_err(device, "drbd_rs_complete_io() called, but extent not found\n");
         return;
     }
 
     if (bm_ext->lce.refcnt == 0) {
         spin_unlock_irqrestore(&device->al_lock, flags);
         drbd_err(device, "drbd_rs_complete_io(,%llu [=%u]) called, "
             "but refcnt is 0!?\n",
             (unsigned long long)sector, enr);
         return;
     }
 
     if (lc_put(device->resync, &bm_ext->lce) == 0) {
         bm_ext->flags = 0; /* clear BME_LOCKED, BME_NO_WRITES and BME_PRIORITY */
         device->resync_locked--;
         wake_up(&device->al_wait);
     }
 
     spin_unlock_irqrestore(&device->al_lock, flags);
 }
 
 /**
  * drbd_rs_cancel_all() - Removes all extents from the resync LRU (even BME_LOCKED)
  * @device: DRBD device.
  */
 void drbd_rs_cancel_all(struct drbd_device *device)
 {
     spin_lock_irq(&device->al_lock);
 
     if (get_ldev_if_state(device, D_FAILED)) { /* Makes sure ->resync is there. */
         lc_reset(device->resync);
         put_ldev(device);
     }
     device->resync_locked = 0;
     device->resync_wenr = LC_FREE;
     spin_unlock_irq(&device->al_lock);
     wake_up(&device->al_wait);
 }
 
 /**
  * drbd_rs_del_all() - Gracefully remove all extents from the resync LRU
  * @device: DRBD device.
  *
  * Returns 0 upon success, -EAGAIN if at least one reference count was
  * not zero.
  */
 int drbd_rs_del_all(struct drbd_device *device)
 {
     struct lc_element *e;
     struct bm_extent *bm_ext;
     int i;
 
     spin_lock_irq(&device->al_lock);
 
     if (get_ldev_if_state(device, D_FAILED)) {
         /* ok, ->resync is there. */
         for (i = 0; i < device->resync->nr_elements; i++) {
             e = lc_element_by_index(device->resync, i);
             bm_ext = lc_entry(e, struct bm_extent, lce);
             if (bm_ext->lce.lc_number == LC_FREE)
                 continue;
             if (bm_ext->lce.lc_number == device->resync_wenr) {
                 drbd_info(device, "dropping %u in drbd_rs_del_all, apparently"
                      " got 'synced' by application io\n",
                      device->resync_wenr);
                 D_ASSERT(device, !test_bit(BME_LOCKED, &bm_ext->flags));
                 D_ASSERT(device, test_bit(BME_NO_WRITES, &bm_ext->flags));
                 clear_bit(BME_NO_WRITES, &bm_ext->flags);
                 device->resync_wenr = LC_FREE;
                 lc_put(device->resync, &bm_ext->lce);
             }
             if (bm_ext->lce.refcnt != 0) {
                 drbd_info(device, "Retrying drbd_rs_del_all() later. "
                      "refcnt=%d\n", bm_ext->lce.refcnt);
                 put_ldev(device);
                 spin_unlock_irq(&device->al_lock);
                 return -EAGAIN;
             }
             D_ASSERT(device, !test_bit(BME_LOCKED, &bm_ext->flags));
             D_ASSERT(device, !test_bit(BME_NO_WRITES, &bm_ext->flags));
             lc_del(device->resync, &bm_ext->lce);
         }
         D_ASSERT(device, device->resync->used == 0);
         put_ldev(device);
     }
     spin_unlock_irq(&device->al_lock);
     wake_up(&device->al_wait);
 
     return 0;
 }

This page was automatically generated by the 2.1.0 LXR engine. The LXR team