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	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
 /*
  * localalloc.c
  *
  * Node local data allocation
  *
  * Copyright (C) 2002, 2004 Oracle.  All rights reserved.
  */
 
 #include <linux/fs.h>
 #include <linux/types.h>
 #include <linux/slab.h>
 #include <linux/highmem.h>
 #include <linux/bitops.h>
 
 #include <cluster/masklog.h>
 
 #include "ocfs2.h"
 
 #include "alloc.h"
 #include "blockcheck.h"
 #include "dlmglue.h"
 #include "inode.h"
 #include "journal.h"
 #include "localalloc.h"
 #include "suballoc.h"
 #include "super.h"
 #include "sysfile.h"
 #include "ocfs2_trace.h"
 
 #include "buffer_head_io.h"
 
 #define OCFS2_LOCAL_ALLOC(dinode)   (&((dinode)->id2.i_lab))
 
 static u32 ocfs2_local_alloc_count_bits(struct ocfs2_dinode *alloc);
 
 static int ocfs2_local_alloc_find_clear_bits(struct ocfs2_super *osb,
                          struct ocfs2_dinode *alloc,
                          u32 *numbits,
                          struct ocfs2_alloc_reservation *resv);
 
 static void ocfs2_clear_local_alloc(struct ocfs2_dinode *alloc);
 
 static int ocfs2_sync_local_to_main(struct ocfs2_super *osb,
                     handle_t *handle,
                     struct ocfs2_dinode *alloc,
                     struct inode *main_bm_inode,
                     struct buffer_head *main_bm_bh);
 
 static int ocfs2_local_alloc_reserve_for_window(struct ocfs2_super *osb,
                         struct ocfs2_alloc_context **ac,
                         struct inode **bitmap_inode,
                         struct buffer_head **bitmap_bh);
 
 static int ocfs2_local_alloc_new_window(struct ocfs2_super *osb,
                     handle_t *handle,
                     struct ocfs2_alloc_context *ac);
 
 static int ocfs2_local_alloc_slide_window(struct ocfs2_super *osb,
                       struct inode *local_alloc_inode);
 
 /*
  * ocfs2_la_default_mb() - determine a default size, in megabytes of
  * the local alloc.
  *
  * Generally, we'd like to pick as large a local alloc as
  * possible. Performance on large workloads tends to scale
  * proportionally to la size. In addition to that, the reservations
  * code functions more efficiently as it can reserve more windows for
  * write.
  *
  * Some things work against us when trying to choose a large local alloc:
  *
  * - We need to ensure our sizing is picked to leave enough space in
  *   group descriptors for other allocations (such as block groups,
  *   etc). Picking default sizes which are a multiple of 4 could help
  *   - block groups are allocated in 2mb and 4mb chunks.
  *
  * - Likewise, we don't want to starve other nodes of bits on small
  *   file systems. This can easily be taken care of by limiting our
  *   default to a reasonable size (256M) on larger cluster sizes.
  *
  * - Some file systems can't support very large sizes - 4k and 8k in
  *   particular are limited to less than 128 and 256 megabytes respectively.
  *
  * The following reference table shows group descriptor and local
  * alloc maximums at various cluster sizes (4k blocksize)
  *
  * csize: 4K    group: 126M la: 121M
  * csize: 8K    group: 252M la: 243M
  * csize: 16K   group: 504M la: 486M
  * csize: 32K   group: 1008M    la: 972M
  * csize: 64K   group: 2016M    la: 1944M
  * csize: 128K  group: 4032M    la: 3888M
  * csize: 256K  group: 8064M    la: 7776M
  * csize: 512K  group: 16128M   la: 15552M
  * csize: 1024K group: 32256M   la: 31104M
  */
 #define OCFS2_LA_MAX_DEFAULT_MB 256
 #define OCFS2_LA_OLD_DEFAULT    8
 unsigned int ocfs2_la_default_mb(struct ocfs2_super *osb)
 {
     unsigned int la_mb;
     unsigned int gd_mb;
     unsigned int la_max_mb;
     unsigned int megs_per_slot;
     struct super_block *sb = osb->sb;
 
     gd_mb = ocfs2_clusters_to_megabytes(osb->sb,
         8 * ocfs2_group_bitmap_size(sb, 0, osb->s_feature_incompat));
 
     /*
      * This takes care of files systems with very small group
      * descriptors - 512 byte blocksize at cluster sizes lower
      * than 16K and also 1k blocksize with 4k cluster size.
      */
     if ((sb->s_blocksize == 512 && osb->s_clustersize <= 8192)
         || (sb->s_blocksize == 1024 && osb->s_clustersize == 4096))
         return OCFS2_LA_OLD_DEFAULT;
 
     /*
      * Leave enough room for some block groups and make the final
      * value we work from a multiple of 4.
      */
     gd_mb -= 16;
     gd_mb &= 0xFFFFFFFB;
 
     la_mb = gd_mb;
 
     /*
      * Keep window sizes down to a reasonable default
      */
     if (la_mb > OCFS2_LA_MAX_DEFAULT_MB) {
         /*
          * Some clustersize / blocksize combinations will have
          * given us a larger than OCFS2_LA_MAX_DEFAULT_MB
          * default size, but get poor distribution when
          * limited to exactly 256 megabytes.
          *
          * As an example, 16K clustersize at 4K blocksize
          * gives us a cluster group size of 504M. Paring the
          * local alloc size down to 256 however, would give us
          * only one window and around 200MB left in the
          * cluster group. Instead, find the first size below
          * 256 which would give us an even distribution.
          *
          * Larger cluster group sizes actually work out pretty
          * well when pared to 256, so we don't have to do this
          * for any group that fits more than two
          * OCFS2_LA_MAX_DEFAULT_MB windows.
          */
         if (gd_mb > (2 * OCFS2_LA_MAX_DEFAULT_MB))
             la_mb = 256;
         else {
             unsigned int gd_mult = gd_mb;
 
             while (gd_mult > 256)
                 gd_mult = gd_mult >> 1;
 
             la_mb = gd_mult;
         }
     }
 
     megs_per_slot = osb->osb_clusters_at_boot / osb->max_slots;
     megs_per_slot = ocfs2_clusters_to_megabytes(osb->sb, megs_per_slot);
     /* Too many nodes, too few disk clusters. */
     if (megs_per_slot < la_mb)
         la_mb = megs_per_slot;
 
     /* We can't store more bits than we can in a block. */
     la_max_mb = ocfs2_clusters_to_megabytes(osb->sb,
                         ocfs2_local_alloc_size(sb) * 8);
     if (la_mb > la_max_mb)
         la_mb = la_max_mb;
 
     return la_mb;
 }
 
 void ocfs2_la_set_sizes(struct ocfs2_super *osb, int requested_mb)
 {
     struct super_block *sb = osb->sb;
     unsigned int la_default_mb = ocfs2_la_default_mb(osb);
     unsigned int la_max_mb;
 
     la_max_mb = ocfs2_clusters_to_megabytes(sb,
                         ocfs2_local_alloc_size(sb) * 8);
 
     trace_ocfs2_la_set_sizes(requested_mb, la_max_mb, la_default_mb);
 
     if (requested_mb == -1) {
         /* No user request - use defaults */
         osb->local_alloc_default_bits =
             ocfs2_megabytes_to_clusters(sb, la_default_mb);
     } else if (requested_mb > la_max_mb) {
         /* Request is too big, we give the maximum available */
         osb->local_alloc_default_bits =
             ocfs2_megabytes_to_clusters(sb, la_max_mb);
     } else {
         osb->local_alloc_default_bits =
             ocfs2_megabytes_to_clusters(sb, requested_mb);
     }
 
     osb->local_alloc_bits = osb->local_alloc_default_bits;
 }
 
 static inline int ocfs2_la_state_enabled(struct ocfs2_super *osb)
 {
     return (osb->local_alloc_state == OCFS2_LA_THROTTLED ||
         osb->local_alloc_state == OCFS2_LA_ENABLED);
 }
 
 void ocfs2_local_alloc_seen_free_bits(struct ocfs2_super *osb,
                       unsigned int num_clusters)
 {
     spin_lock(&osb->osb_lock);
     if (osb->local_alloc_state == OCFS2_LA_DISABLED ||
         osb->local_alloc_state == OCFS2_LA_THROTTLED)
         if (num_clusters >= osb->local_alloc_default_bits) {
             cancel_delayed_work(&osb->la_enable_wq);
             osb->local_alloc_state = OCFS2_LA_ENABLED;
         }
     spin_unlock(&osb->osb_lock);
 }
 
 void ocfs2_la_enable_worker(struct work_struct *work)
 {
     struct ocfs2_super *osb =
         container_of(work, struct ocfs2_super,
                  la_enable_wq.work);
     spin_lock(&osb->osb_lock);
     osb->local_alloc_state = OCFS2_LA_ENABLED;
     spin_unlock(&osb->osb_lock);
 }
 
 /*
  * Tell us whether a given allocation should use the local alloc
  * file. Otherwise, it has to go to the main bitmap.
  *
  * This function does semi-dirty reads of local alloc size and state!
  * This is ok however, as the values are re-checked once under mutex.
  */
 int ocfs2_alloc_should_use_local(struct ocfs2_super *osb, u64 bits)
 {
     int ret = 0;
     int la_bits;
 
     spin_lock(&osb->osb_lock);
     la_bits = osb->local_alloc_bits;
 
     if (!ocfs2_la_state_enabled(osb))
         goto bail;
 
     /* la_bits should be at least twice the size (in clusters) of
      * a new block group. We want to be sure block group
      * allocations go through the local alloc, so allow an
      * allocation to take up to half the bitmap. */
     if (bits > (la_bits / 2))
         goto bail;
 
     ret = 1;
 bail:
     trace_ocfs2_alloc_should_use_local(
          (unsigned long long)bits, osb->local_alloc_state, la_bits, ret);
     spin_unlock(&osb->osb_lock);
     return ret;
 }
 
 int ocfs2_load_local_alloc(struct ocfs2_super *osb)
 {
     int status = 0;
     struct ocfs2_dinode *alloc = NULL;
     struct buffer_head *alloc_bh = NULL;
     u32 num_used;
     struct inode *inode = NULL;
     struct ocfs2_local_alloc *la;
 
     if (osb->local_alloc_bits == 0)
         goto bail;
 
     if (osb->local_alloc_bits >= osb->bitmap_cpg) {
         mlog(ML_NOTICE, "Requested local alloc window %d is larger "
              "than max possible %u. Using defaults.\n",
              osb->local_alloc_bits, (osb->bitmap_cpg - 1));
         osb->local_alloc_bits =
             ocfs2_megabytes_to_clusters(osb->sb,
                             ocfs2_la_default_mb(osb));
     }
 
     /* read the alloc off disk */
     inode = ocfs2_get_system_file_inode(osb, LOCAL_ALLOC_SYSTEM_INODE,
                         osb->slot_num);
     if (!inode) {
         status = -EINVAL;
         mlog_errno(status);
         goto bail;
     }
 
     status = ocfs2_read_inode_block_full(inode, &alloc_bh,
                          OCFS2_BH_IGNORE_CACHE);
     if (status < 0) {
         mlog_errno(status);
         goto bail;
     }
 
     alloc = (struct ocfs2_dinode *) alloc_bh->b_data;
     la = OCFS2_LOCAL_ALLOC(alloc);
 
     if (!(le32_to_cpu(alloc->i_flags) &
         (OCFS2_LOCAL_ALLOC_FL|OCFS2_BITMAP_FL))) {
         mlog(ML_ERROR, "Invalid local alloc inode, %llu\n",
              (unsigned long long)OCFS2_I(inode)->ip_blkno);
         status = -EINVAL;
         goto bail;
     }
 
     if ((la->la_size == 0) ||
         (le16_to_cpu(la->la_size) > ocfs2_local_alloc_size(inode->i_sb))) {
         mlog(ML_ERROR, "Local alloc size is invalid (la_size = %u)\n",
              le16_to_cpu(la->la_size));
         status = -EINVAL;
         goto bail;
     }
 
     /* do a little verification. */
     num_used = ocfs2_local_alloc_count_bits(alloc);
 
     /* hopefully the local alloc has always been recovered before
      * we load it. */
     if (num_used
         || alloc->id1.bitmap1.i_used
         || alloc->id1.bitmap1.i_total
         || la->la_bm_off) {
         mlog(ML_ERROR, "inconsistent detected, clean journal with"
              " unrecovered local alloc, please run fsck.ocfs2!\n"
              "found = %u, set = %u, taken = %u, off = %u\n",
              num_used, le32_to_cpu(alloc->id1.bitmap1.i_used),
              le32_to_cpu(alloc->id1.bitmap1.i_total),
              OCFS2_LOCAL_ALLOC(alloc)->la_bm_off);
 
         status = -EINVAL;
         goto bail;
     }
 
     osb->local_alloc_bh = alloc_bh;
     osb->local_alloc_state = OCFS2_LA_ENABLED;
 
 bail:
     if (status < 0)
         brelse(alloc_bh);
     iput(inode);
 
     trace_ocfs2_load_local_alloc(osb->local_alloc_bits);
 
     if (status)
         mlog_errno(status);
     return status;
 }
 
 /*
  * return any unused bits to the bitmap and write out a clean
  * local_alloc.
  *
  * local_alloc_bh is optional. If not passed, we will simply use the
  * one off osb. If you do pass it however, be warned that it *will* be
  * returned brelse'd and NULL'd out.*/
 void ocfs2_shutdown_local_alloc(struct ocfs2_super *osb)
 {
     int status;
     handle_t *handle;
     struct inode *local_alloc_inode = NULL;
     struct buffer_head *bh = NULL;
     struct buffer_head *main_bm_bh = NULL;
     struct inode *main_bm_inode = NULL;
     struct ocfs2_dinode *alloc_copy = NULL;
     struct ocfs2_dinode *alloc = NULL;
 
     cancel_delayed_work(&osb->la_enable_wq);
     if (osb->ocfs2_wq)
         flush_workqueue(osb->ocfs2_wq);
 
     if (osb->local_alloc_state == OCFS2_LA_UNUSED)
         goto out;
 
     local_alloc_inode =
         ocfs2_get_system_file_inode(osb,
                         LOCAL_ALLOC_SYSTEM_INODE,
                         osb->slot_num);
     if (!local_alloc_inode) {
         status = -ENOENT;
         mlog_errno(status);
         goto out;
     }
 
     osb->local_alloc_state = OCFS2_LA_DISABLED;
 
     ocfs2_resmap_uninit(&osb->osb_la_resmap);
 
     main_bm_inode = ocfs2_get_system_file_inode(osb,
                             GLOBAL_BITMAP_SYSTEM_INODE,
                             OCFS2_INVALID_SLOT);
     if (!main_bm_inode) {
         status = -EINVAL;
         mlog_errno(status);
         goto out;
     }
 
     inode_lock(main_bm_inode);
 
     status = ocfs2_inode_lock(main_bm_inode, &main_bm_bh, 1);
     if (status < 0) {
         mlog_errno(status);
         goto out_mutex;
     }
 
     /* WINDOW_MOVE_CREDITS is a bit heavy... */
     handle = ocfs2_start_trans(osb, OCFS2_WINDOW_MOVE_CREDITS);
     if (IS_ERR(handle)) {
         mlog_errno(PTR_ERR(handle));
         handle = NULL;
         goto out_unlock;
     }
 
     bh = osb->local_alloc_bh;
     alloc = (struct ocfs2_dinode *) bh->b_data;
 
     alloc_copy = kmemdup(alloc, bh->b_size, GFP_NOFS);
     if (!alloc_copy) {
         status = -ENOMEM;
         goto out_commit;
     }
 
     status = ocfs2_journal_access_di(handle, INODE_CACHE(local_alloc_inode),
                      bh, OCFS2_JOURNAL_ACCESS_WRITE);
     if (status < 0) {
         mlog_errno(status);
         goto out_commit;
     }
 
     ocfs2_clear_local_alloc(alloc);
     ocfs2_journal_dirty(handle, bh);
 
     brelse(bh);
     osb->local_alloc_bh = NULL;
     osb->local_alloc_state = OCFS2_LA_UNUSED;
 
     status = ocfs2_sync_local_to_main(osb, handle, alloc_copy,
                       main_bm_inode, main_bm_bh);
     if (status < 0)
         mlog_errno(status);
 
 out_commit:
     ocfs2_commit_trans(osb, handle);
 
 out_unlock:
     brelse(main_bm_bh);
 
     ocfs2_inode_unlock(main_bm_inode, 1);
 
 out_mutex:
     inode_unlock(main_bm_inode);
     iput(main_bm_inode);
 
 out:
     iput(local_alloc_inode);
 
     kfree(alloc_copy);
 }
 
 /*
  * We want to free the bitmap bits outside of any recovery context as
  * we'll need a cluster lock to do so, but we must clear the local
  * alloc before giving up the recovered nodes journal. To solve this,
  * we kmalloc a copy of the local alloc before it's change for the
  * caller to process with ocfs2_complete_local_alloc_recovery
  */
 int ocfs2_begin_local_alloc_recovery(struct ocfs2_super *osb,
                      int slot_num,
                      struct ocfs2_dinode **alloc_copy)
 {
     int status = 0;
     struct buffer_head *alloc_bh = NULL;
     struct inode *inode = NULL;
     struct ocfs2_dinode *alloc;
 
     trace_ocfs2_begin_local_alloc_recovery(slot_num);
 
     *alloc_copy = NULL;
 
     inode = ocfs2_get_system_file_inode(osb,
                         LOCAL_ALLOC_SYSTEM_INODE,
                         slot_num);
     if (!inode) {
         status = -EINVAL;
         mlog_errno(status);
         goto bail;
     }
 
     inode_lock(inode);
 
     status = ocfs2_read_inode_block_full(inode, &alloc_bh,
                          OCFS2_BH_IGNORE_CACHE);
     if (status < 0) {
         mlog_errno(status);
         goto bail;
     }
 
     *alloc_copy = kmalloc(alloc_bh->b_size, GFP_KERNEL);
     if (!(*alloc_copy)) {
         status = -ENOMEM;
         goto bail;
     }
     memcpy((*alloc_copy), alloc_bh->b_data, alloc_bh->b_size);
 
     alloc = (struct ocfs2_dinode *) alloc_bh->b_data;
     ocfs2_clear_local_alloc(alloc);
 
     ocfs2_compute_meta_ecc(osb->sb, alloc_bh->b_data, &alloc->i_check);
     status = ocfs2_write_block(osb, alloc_bh, INODE_CACHE(inode));
     if (status < 0)
         mlog_errno(status);
 
 bail:
     if (status < 0) {
         kfree(*alloc_copy);
         *alloc_copy = NULL;
     }
 
     brelse(alloc_bh);
 
     if (inode) {
         inode_unlock(inode);
         iput(inode);
     }
 
     if (status)
         mlog_errno(status);
     return status;
 }
 
 /*
  * Step 2: By now, we've completed the journal recovery, we've stamped
  * a clean local alloc on disk and dropped the node out of the
  * recovery map. Dlm locks will no longer stall, so lets clear out the
  * main bitmap.
  */
 int ocfs2_complete_local_alloc_recovery(struct ocfs2_super *osb,
                     struct ocfs2_dinode *alloc)
 {
     int status;
     handle_t *handle;
     struct buffer_head *main_bm_bh = NULL;
     struct inode *main_bm_inode;
 
     main_bm_inode = ocfs2_get_system_file_inode(osb,
                             GLOBAL_BITMAP_SYSTEM_INODE,
                             OCFS2_INVALID_SLOT);
     if (!main_bm_inode) {
         status = -EINVAL;
         mlog_errno(status);
         goto out;
     }
 
     inode_lock(main_bm_inode);
 
     status = ocfs2_inode_lock(main_bm_inode, &main_bm_bh, 1);
     if (status < 0) {
         mlog_errno(status);
         goto out_mutex;
     }
 
     handle = ocfs2_start_trans(osb, OCFS2_WINDOW_MOVE_CREDITS);
     if (IS_ERR(handle)) {
         status = PTR_ERR(handle);
         handle = NULL;
         mlog_errno(status);
         goto out_unlock;
     }
 
     /* we want the bitmap change to be recorded on disk asap */
     handle->h_sync = 1;
 
     status = ocfs2_sync_local_to_main(osb, handle, alloc,
                       main_bm_inode, main_bm_bh);
     if (status < 0)
         mlog_errno(status);
 
     ocfs2_commit_trans(osb, handle);
 
 out_unlock:
     ocfs2_inode_unlock(main_bm_inode, 1);
 
 out_mutex:
     inode_unlock(main_bm_inode);
 
     brelse(main_bm_bh);
 
     iput(main_bm_inode);
 
 out:
     if (!status)
         ocfs2_init_steal_slots(osb);
     if (status)
         mlog_errno(status);
     return status;
 }
 
 /*
  * make sure we've got at least bits_wanted contiguous bits in the
  * local alloc. You lose them when you drop i_rwsem.
  *
  * We will add ourselves to the transaction passed in, but may start
  * our own in order to shift windows.
  */
 int ocfs2_reserve_local_alloc_bits(struct ocfs2_super *osb,
                    u32 bits_wanted,
                    struct ocfs2_alloc_context *ac)
 {
     int status;
     struct ocfs2_dinode *alloc;
     struct inode *local_alloc_inode;
     unsigned int free_bits;
 
     BUG_ON(!ac);
 
     local_alloc_inode =
         ocfs2_get_system_file_inode(osb,
                         LOCAL_ALLOC_SYSTEM_INODE,
                         osb->slot_num);
     if (!local_alloc_inode) {
         status = -ENOENT;
         mlog_errno(status);
         goto bail;
     }
 
     inode_lock(local_alloc_inode);
 
     /*
      * We must double check state and allocator bits because
      * another process may have changed them while holding i_rwsem.
      */
     spin_lock(&osb->osb_lock);
     if (!ocfs2_la_state_enabled(osb) ||
         (bits_wanted > osb->local_alloc_bits)) {
         spin_unlock(&osb->osb_lock);
         status = -ENOSPC;
         goto bail;
     }
     spin_unlock(&osb->osb_lock);
 
     alloc = (struct ocfs2_dinode *) osb->local_alloc_bh->b_data;
 
 #ifdef CONFIG_OCFS2_DEBUG_FS
     if (le32_to_cpu(alloc->id1.bitmap1.i_used) !=
         ocfs2_local_alloc_count_bits(alloc)) {
         status = ocfs2_error(osb->sb, "local alloc inode %llu says it has %u used bits, but a count shows %u\n",
                 (unsigned long long)le64_to_cpu(alloc->i_blkno),
                 le32_to_cpu(alloc->id1.bitmap1.i_used),
                 ocfs2_local_alloc_count_bits(alloc));
         goto bail;
     }
 #endif
 
     free_bits = le32_to_cpu(alloc->id1.bitmap1.i_total) -
         le32_to_cpu(alloc->id1.bitmap1.i_used);
     if (bits_wanted > free_bits) {
         /* uhoh, window change time. */
         status =
             ocfs2_local_alloc_slide_window(osb, local_alloc_inode);
         if (status < 0) {
             if (status != -ENOSPC)
                 mlog_errno(status);
             goto bail;
         }
 
         /*
          * Under certain conditions, the window slide code
          * might have reduced the number of bits available or
          * disabled the local alloc entirely. Re-check
          * here and return -ENOSPC if necessary.
          */
         status = -ENOSPC;
         if (!ocfs2_la_state_enabled(osb))
             goto bail;
 
         free_bits = le32_to_cpu(alloc->id1.bitmap1.i_total) -
             le32_to_cpu(alloc->id1.bitmap1.i_used);
         if (bits_wanted > free_bits)
             goto bail;
     }
 
     ac->ac_inode = local_alloc_inode;
     /* We should never use localalloc from another slot */
     ac->ac_alloc_slot = osb->slot_num;
     ac->ac_which = OCFS2_AC_USE_LOCAL;
     get_bh(osb->local_alloc_bh);
     ac->ac_bh = osb->local_alloc_bh;
     status = 0;
 bail:
     if (status < 0 && local_alloc_inode) {
         inode_unlock(local_alloc_inode);
         iput(local_alloc_inode);
     }
 
     trace_ocfs2_reserve_local_alloc_bits(
         (unsigned long long)ac->ac_max_block,
         bits_wanted, osb->slot_num, status);
 
     if (status)
         mlog_errno(status);
     return status;
 }
 
 int ocfs2_claim_local_alloc_bits(struct ocfs2_super *osb,
                  handle_t *handle,
                  struct ocfs2_alloc_context *ac,
                  u32 bits_wanted,
                  u32 *bit_off,
                  u32 *num_bits)
 {
     int status, start;
     struct inode *local_alloc_inode;
     void *bitmap;
     struct ocfs2_dinode *alloc;
     struct ocfs2_local_alloc *la;
 
     BUG_ON(ac->ac_which != OCFS2_AC_USE_LOCAL);
 
     local_alloc_inode = ac->ac_inode;
     alloc = (struct ocfs2_dinode *) osb->local_alloc_bh->b_data;
     la = OCFS2_LOCAL_ALLOC(alloc);
 
     start = ocfs2_local_alloc_find_clear_bits(osb, alloc, &bits_wanted,
                           ac->ac_resv);
     if (start == -1) {
         /* TODO: Shouldn't we just BUG here? */
         status = -ENOSPC;
         mlog_errno(status);
         goto bail;
     }
 
     bitmap = la->la_bitmap;
     *bit_off = le32_to_cpu(la->la_bm_off) + start;
     *num_bits = bits_wanted;
 
     status = ocfs2_journal_access_di(handle,
                      INODE_CACHE(local_alloc_inode),
                      osb->local_alloc_bh,
                      OCFS2_JOURNAL_ACCESS_WRITE);
     if (status < 0) {
         mlog_errno(status);
         goto bail;
     }
 
     ocfs2_resmap_claimed_bits(&osb->osb_la_resmap, ac->ac_resv, start,
                   bits_wanted);
 
     while(bits_wanted--)
         ocfs2_set_bit(start++, bitmap);
 
     le32_add_cpu(&alloc->id1.bitmap1.i_used, *num_bits);
     ocfs2_journal_dirty(handle, osb->local_alloc_bh);
 
 bail:
     if (status)
         mlog_errno(status);
     return status;
 }
 
 int ocfs2_free_local_alloc_bits(struct ocfs2_super *osb,
                 handle_t *handle,
                 struct ocfs2_alloc_context *ac,
                 u32 bit_off,
                 u32 num_bits)
 {
     int status, start;
     u32 clear_bits;
     struct inode *local_alloc_inode;
     void *bitmap;
     struct ocfs2_dinode *alloc;
     struct ocfs2_local_alloc *la;
 
     BUG_ON(ac->ac_which != OCFS2_AC_USE_LOCAL);
 
     local_alloc_inode = ac->ac_inode;
     alloc = (struct ocfs2_dinode *) osb->local_alloc_bh->b_data;
     la = OCFS2_LOCAL_ALLOC(alloc);
 
     bitmap = la->la_bitmap;
     start = bit_off - le32_to_cpu(la->la_bm_off);
     clear_bits = num_bits;
 
     status = ocfs2_journal_access_di(handle,
             INODE_CACHE(local_alloc_inode),
             osb->local_alloc_bh,
             OCFS2_JOURNAL_ACCESS_WRITE);
     if (status < 0) {
         mlog_errno(status);
         goto bail;
     }
 
     while (clear_bits--)
         ocfs2_clear_bit(start++, bitmap);
 
     le32_add_cpu(&alloc->id1.bitmap1.i_used, -num_bits);
     ocfs2_journal_dirty(handle, osb->local_alloc_bh);
 
 bail:
     return status;
 }
 
 static u32 ocfs2_local_alloc_count_bits(struct ocfs2_dinode *alloc)
 {
     u32 count;
     struct ocfs2_local_alloc *la = OCFS2_LOCAL_ALLOC(alloc);
 
     count = memweight(la->la_bitmap, le16_to_cpu(la->la_size));
 
     trace_ocfs2_local_alloc_count_bits(count);
     return count;
 }
 
 static int ocfs2_local_alloc_find_clear_bits(struct ocfs2_super *osb,
                      struct ocfs2_dinode *alloc,
                      u32 *numbits,
                      struct ocfs2_alloc_reservation *resv)
 {
     int numfound = 0, bitoff, left, startoff;
     int local_resv = 0;
     struct ocfs2_alloc_reservation r;
     void *bitmap = NULL;
     struct ocfs2_reservation_map *resmap = &osb->osb_la_resmap;
 
     if (!alloc->id1.bitmap1.i_total) {
         bitoff = -1;
         goto bail;
     }
 
     if (!resv) {
         local_resv = 1;
         ocfs2_resv_init_once(&r);
         ocfs2_resv_set_type(&r, OCFS2_RESV_FLAG_TMP);
         resv = &r;
     }
 
     numfound = *numbits;
     if (ocfs2_resmap_resv_bits(resmap, resv, &bitoff, &numfound) == 0) {
         if (numfound < *numbits)
             *numbits = numfound;
         goto bail;
     }
 
     /*
      * Code error. While reservations are enabled, local
      * allocation should _always_ go through them.
      */
     BUG_ON(osb->osb_resv_level != 0);
 
     /*
      * Reservations are disabled. Handle this the old way.
      */
 
     bitmap = OCFS2_LOCAL_ALLOC(alloc)->la_bitmap;
 
     numfound = bitoff = startoff = 0;
     left = le32_to_cpu(alloc->id1.bitmap1.i_total);
     while ((bitoff = ocfs2_find_next_zero_bit(bitmap, left, startoff)) != -1) {
         if (bitoff == left) {
             /* mlog(0, "bitoff (%d) == left", bitoff); */
             break;
         }
         /* mlog(0, "Found a zero: bitoff = %d, startoff = %d, "
            "numfound = %d\n", bitoff, startoff, numfound);*/
 
         /* Ok, we found a zero bit... is it contig. or do we
          * start over?*/
         if (bitoff == startoff) {
             /* we found a zero */
             numfound++;
             startoff++;
         } else {
             /* got a zero after some ones */
             numfound = 1;
             startoff = bitoff+1;
         }
         /* we got everything we needed */
         if (numfound == *numbits) {
             /* mlog(0, "Found it all!\n"); */
             break;
         }
     }
 
     trace_ocfs2_local_alloc_find_clear_bits_search_bitmap(bitoff, numfound);
 
     if (numfound == *numbits)
         bitoff = startoff - numfound;
     else
         bitoff = -1;
 
 bail:
     if (local_resv)
         ocfs2_resv_discard(resmap, resv);
 
     trace_ocfs2_local_alloc_find_clear_bits(*numbits,
         le32_to_cpu(alloc->id1.bitmap1.i_total),
         bitoff, numfound);
 
     return bitoff;
 }
 
 static void ocfs2_clear_local_alloc(struct ocfs2_dinode *alloc)
 {
     struct ocfs2_local_alloc *la = OCFS2_LOCAL_ALLOC(alloc);
     int i;
 
     alloc->id1.bitmap1.i_total = 0;
     alloc->id1.bitmap1.i_used = 0;
     la->la_bm_off = 0;
     for(i = 0; i < le16_to_cpu(la->la_size); i++)
         la->la_bitmap[i] = 0;
 }
 
 #if 0
 /* turn this on and uncomment below to aid debugging window shifts. */
 static void ocfs2_verify_zero_bits(unsigned long *bitmap,
                    unsigned int start,
                    unsigned int count)
 {
     unsigned int tmp = count;
     while(tmp--) {
         if (ocfs2_test_bit(start + tmp, bitmap)) {
             printk("ocfs2_verify_zero_bits: start = %u, count = "
                    "%u\n", start, count);
             printk("ocfs2_verify_zero_bits: bit %u is set!",
                    start + tmp);
             BUG();
         }
     }
 }
 #endif
 
 /*
  * sync the local alloc to main bitmap.
  *
  * assumes you've already locked the main bitmap -- the bitmap inode
  * passed is used for caching.
  */
 static int ocfs2_sync_local_to_main(struct ocfs2_super *osb,
                     handle_t *handle,
                     struct ocfs2_dinode *alloc,
                     struct inode *main_bm_inode,
                     struct buffer_head *main_bm_bh)
 {
     int status = 0;
     int bit_off, left, count, start;
     u64 la_start_blk;
     u64 blkno;
     void *bitmap;
     struct ocfs2_local_alloc *la = OCFS2_LOCAL_ALLOC(alloc);
 
     trace_ocfs2_sync_local_to_main(
          le32_to_cpu(alloc->id1.bitmap1.i_total),
          le32_to_cpu(alloc->id1.bitmap1.i_used));
 
     if (!alloc->id1.bitmap1.i_total) {
         goto bail;
     }
 
     if (le32_to_cpu(alloc->id1.bitmap1.i_used) ==
         le32_to_cpu(alloc->id1.bitmap1.i_total)) {
         goto bail;
     }
 
     la_start_blk = ocfs2_clusters_to_blocks(osb->sb,
                         le32_to_cpu(la->la_bm_off));
     bitmap = la->la_bitmap;
     start = count = bit_off = 0;
     left = le32_to_cpu(alloc->id1.bitmap1.i_total);
 
     while ((bit_off = ocfs2_find_next_zero_bit(bitmap, left, start))
            != -1) {
         if ((bit_off < left) && (bit_off == start)) {
             count++;
             start++;
             continue;
         }
         if (count) {
             blkno = la_start_blk +
                 ocfs2_clusters_to_blocks(osb->sb,
                              start - count);
 
             trace_ocfs2_sync_local_to_main_free(
                  count, start - count,
                  (unsigned long long)la_start_blk,
                  (unsigned long long)blkno);
 
             status = ocfs2_release_clusters(handle,
                             main_bm_inode,
                             main_bm_bh, blkno,
                             count);
             if (status < 0) {
                 mlog_errno(status);
                 goto bail;
             }
         }
         if (bit_off >= left)
             break;
         count = 1;
         start = bit_off + 1;
     }
 
 bail:
     if (status)
         mlog_errno(status);
     return status;
 }
 
 enum ocfs2_la_event {
     OCFS2_LA_EVENT_SLIDE,       /* Normal window slide. */
     OCFS2_LA_EVENT_FRAGMENTED,  /* The global bitmap has
                      * enough bits theoretically
                      * free, but a contiguous
                      * allocation could not be
                      * found. */
     OCFS2_LA_EVENT_ENOSPC,      /* Global bitmap doesn't have
                      * enough bits free to satisfy
                      * our request. */
 };
 #define OCFS2_LA_ENABLE_INTERVAL (30 * HZ)
 /*
  * Given an event, calculate the size of our next local alloc window.
  *
  * This should always be called under i_rwsem of the local alloc inode
  * so that local alloc disabling doesn't race with processes trying to
  * use the allocator.
  *
  * Returns the state which the local alloc was left in. This value can
  * be ignored by some paths.
  */
 static int ocfs2_recalc_la_window(struct ocfs2_super *osb,
                   enum ocfs2_la_event event)
 {
     unsigned int bits;
     int state;
 
     spin_lock(&osb->osb_lock);
     if (osb->local_alloc_state == OCFS2_LA_DISABLED) {
         WARN_ON_ONCE(osb->local_alloc_state == OCFS2_LA_DISABLED);
         goto out_unlock;
     }
 
     /*
      * ENOSPC and fragmentation are treated similarly for now.
      */
     if (event == OCFS2_LA_EVENT_ENOSPC ||
         event == OCFS2_LA_EVENT_FRAGMENTED) {
         /*
          * We ran out of contiguous space in the primary
          * bitmap. Drastically reduce the number of bits used
          * by local alloc until we have to disable it.
          */
         bits = osb->local_alloc_bits >> 1;
         if (bits > ocfs2_megabytes_to_clusters(osb->sb, 1)) {
             /*
              * By setting state to THROTTLED, we'll keep
              * the number of local alloc bits used down
              * until an event occurs which would give us
              * reason to assume the bitmap situation might
              * have changed.
              */
             osb->local_alloc_state = OCFS2_LA_THROTTLED;
             osb->local_alloc_bits = bits;
         } else {
             osb->local_alloc_state = OCFS2_LA_DISABLED;
         }
         queue_delayed_work(osb->ocfs2_wq, &osb->la_enable_wq,
                    OCFS2_LA_ENABLE_INTERVAL);
         goto out_unlock;
     }
 
     /*
      * Don't increase the size of the local alloc window until we
      * know we might be able to fulfill the request. Otherwise, we
      * risk bouncing around the global bitmap during periods of
      * low space.
      */
     if (osb->local_alloc_state != OCFS2_LA_THROTTLED)
         osb->local_alloc_bits = osb->local_alloc_default_bits;
 
 out_unlock:
     state = osb->local_alloc_state;
     spin_unlock(&osb->osb_lock);
 
     return state;
 }
 
 static int ocfs2_local_alloc_reserve_for_window(struct ocfs2_super *osb,
                         struct ocfs2_alloc_context **ac,
                         struct inode **bitmap_inode,
                         struct buffer_head **bitmap_bh)
 {
     int status;
 
     *ac = kzalloc(sizeof(struct ocfs2_alloc_context), GFP_KERNEL);
     if (!(*ac)) {
         status = -ENOMEM;
         mlog_errno(status);
         goto bail;
     }
 
 retry_enospc:
     (*ac)->ac_bits_wanted = osb->local_alloc_bits;
     status = ocfs2_reserve_cluster_bitmap_bits(osb, *ac);
     if (status == -ENOSPC) {
         if (ocfs2_recalc_la_window(osb, OCFS2_LA_EVENT_ENOSPC) ==
             OCFS2_LA_DISABLED)
             goto bail;
 
         ocfs2_free_ac_resource(*ac);
         memset(*ac, 0, sizeof(struct ocfs2_alloc_context));
         goto retry_enospc;
     }
     if (status < 0) {
         mlog_errno(status);
         goto bail;
     }
 
     *bitmap_inode = (*ac)->ac_inode;
     igrab(*bitmap_inode);
     *bitmap_bh = (*ac)->ac_bh;
     get_bh(*bitmap_bh);
     status = 0;
 bail:
     if ((status < 0) && *ac) {
         ocfs2_free_alloc_context(*ac);
         *ac = NULL;
     }
 
     if (status)
         mlog_errno(status);
     return status;
 }
 
 /*
  * pass it the bitmap lock in lock_bh if you have it.
  */
 static int ocfs2_local_alloc_new_window(struct ocfs2_super *osb,
                     handle_t *handle,
                     struct ocfs2_alloc_context *ac)
 {
     int status = 0;
     u32 cluster_off, cluster_count;
     struct ocfs2_dinode *alloc = NULL;
     struct ocfs2_local_alloc *la;
 
     alloc = (struct ocfs2_dinode *) osb->local_alloc_bh->b_data;
     la = OCFS2_LOCAL_ALLOC(alloc);
 
     trace_ocfs2_local_alloc_new_window(
         le32_to_cpu(alloc->id1.bitmap1.i_total),
         osb->local_alloc_bits);
 
     /* Instruct the allocation code to try the most recently used
      * cluster group. We'll re-record the group used this pass
      * below. */
     ac->ac_last_group = osb->la_last_gd;
 
     /* we used the generic suballoc reserve function, but we set
      * everything up nicely, so there's no reason why we can't use
      * the more specific cluster api to claim bits. */
     status = ocfs2_claim_clusters(handle, ac, osb->local_alloc_bits,
                       &cluster_off, &cluster_count);
     if (status == -ENOSPC) {
 retry_enospc:
         /*
          * Note: We could also try syncing the journal here to
          * allow use of any free bits which the current
          * transaction can't give us access to. --Mark
          */
         if (ocfs2_recalc_la_window(osb, OCFS2_LA_EVENT_FRAGMENTED) ==
             OCFS2_LA_DISABLED)
             goto bail;
 
         ac->ac_bits_wanted = osb->local_alloc_bits;
         status = ocfs2_claim_clusters(handle, ac,
                           osb->local_alloc_bits,
                           &cluster_off,
                           &cluster_count);
         if (status == -ENOSPC)
             goto retry_enospc;
         /*
          * We only shrunk the *minimum* number of in our
          * request - it's entirely possible that the allocator
          * might give us more than we asked for.
          */
         if (status == 0) {
             spin_lock(&osb->osb_lock);
             osb->local_alloc_bits = cluster_count;
             spin_unlock(&osb->osb_lock);
         }
     }
     if (status < 0) {
         if (status != -ENOSPC)
             mlog_errno(status);
         goto bail;
     }
 
     osb->la_last_gd = ac->ac_last_group;
 
     la->la_bm_off = cpu_to_le32(cluster_off);
     alloc->id1.bitmap1.i_total = cpu_to_le32(cluster_count);
     /* just in case... In the future when we find space ourselves,
      * we don't have to get all contiguous -- but we'll have to
      * set all previously used bits in bitmap and update
      * la_bits_set before setting the bits in the main bitmap. */
     alloc->id1.bitmap1.i_used = 0;
     memset(OCFS2_LOCAL_ALLOC(alloc)->la_bitmap, 0,
            le16_to_cpu(la->la_size));
 
     ocfs2_resmap_restart(&osb->osb_la_resmap, cluster_count,
                  OCFS2_LOCAL_ALLOC(alloc)->la_bitmap);
 
     trace_ocfs2_local_alloc_new_window_result(
         OCFS2_LOCAL_ALLOC(alloc)->la_bm_off,
         le32_to_cpu(alloc->id1.bitmap1.i_total));
 
 bail:
     if (status)
         mlog_errno(status);
     return status;
 }
 
 /* Note that we do *NOT* lock the local alloc inode here as
  * it's been locked already for us. */
 static int ocfs2_local_alloc_slide_window(struct ocfs2_super *osb,
                       struct inode *local_alloc_inode)
 {
     int status = 0;
     struct buffer_head *main_bm_bh = NULL;
     struct inode *main_bm_inode = NULL;
     handle_t *handle = NULL;
     struct ocfs2_dinode *alloc;
     struct ocfs2_dinode *alloc_copy = NULL;
     struct ocfs2_alloc_context *ac = NULL;
 
     ocfs2_recalc_la_window(osb, OCFS2_LA_EVENT_SLIDE);
 
     /* This will lock the main bitmap for us. */
     status = ocfs2_local_alloc_reserve_for_window(osb,
                               &ac,
                               &main_bm_inode,
                               &main_bm_bh);
     if (status < 0) {
         if (status != -ENOSPC)
             mlog_errno(status);
         goto bail;
     }
 
     handle = ocfs2_start_trans(osb, OCFS2_WINDOW_MOVE_CREDITS);
     if (IS_ERR(handle)) {
         status = PTR_ERR(handle);
         handle = NULL;
         mlog_errno(status);
         goto bail;
     }
 
     alloc = (struct ocfs2_dinode *) osb->local_alloc_bh->b_data;
 
     /* We want to clear the local alloc before doing anything
      * else, so that if we error later during this operation,
      * local alloc shutdown won't try to double free main bitmap
      * bits. Make a copy so the sync function knows which bits to
      * free. */
     alloc_copy = kmemdup(alloc, osb->local_alloc_bh->b_size, GFP_NOFS);
     if (!alloc_copy) {
         status = -ENOMEM;
         mlog_errno(status);
         goto bail;
     }
 
     status = ocfs2_journal_access_di(handle,
                      INODE_CACHE(local_alloc_inode),
                      osb->local_alloc_bh,
                      OCFS2_JOURNAL_ACCESS_WRITE);
     if (status < 0) {
         mlog_errno(status);
         goto bail;
     }
 
     ocfs2_clear_local_alloc(alloc);
     ocfs2_journal_dirty(handle, osb->local_alloc_bh);
 
     status = ocfs2_sync_local_to_main(osb, handle, alloc_copy,
                       main_bm_inode, main_bm_bh);
     if (status < 0) {
         mlog_errno(status);
         goto bail;
     }
 
     status = ocfs2_local_alloc_new_window(osb, handle, ac);
     if (status < 0) {
         if (status != -ENOSPC)
             mlog_errno(status);
         goto bail;
     }
 
     atomic_inc(&osb->alloc_stats.moves);
 
 bail:
     if (handle)
         ocfs2_commit_trans(osb, handle);
 
     brelse(main_bm_bh);
 
     iput(main_bm_inode);
     kfree(alloc_copy);
 
     if (ac)
         ocfs2_free_alloc_context(ac);
 
     if (status)
         mlog_errno(status);
     return status;
 }
 

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