diff options
| -rw-r--r-- | fs/btrfs/block-group.c | 28 | ||||
| -rw-r--r-- | fs/btrfs/block-group.h | 6 |
2 files changed, 33 insertions, 1 deletions
diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c index b1f4acdeafb9..47461fd21975 100644 --- a/fs/btrfs/block-group.c +++ b/fs/btrfs/block-group.c @@ -2071,6 +2071,7 @@ static int read_one_block_group(struct btrfs_fs_info *info, cache->length = key->offset; cache->used = btrfs_stack_block_group_used(bgi); + cache->commit_used = cache->used; cache->flags = btrfs_stack_block_group_flags(bgi); cache->global_root_id = btrfs_stack_block_group_chunk_objectid(bgi); @@ -2762,6 +2763,25 @@ static int update_block_group_item(struct btrfs_trans_handle *trans, struct extent_buffer *leaf; struct btrfs_block_group_item bgi; struct btrfs_key key; + u64 old_commit_used; + u64 used; + + /* + * Block group items update can be triggered out of commit transaction + * critical section, thus we need a consistent view of used bytes. + * We cannot use cache->used directly outside of the spin lock, as it + * may be changed. + */ + spin_lock(&cache->lock); + old_commit_used = cache->commit_used; + used = cache->used; + /* No change in used bytes, can safely skip it. */ + if (cache->commit_used == used) { + spin_unlock(&cache->lock); + return 0; + } + cache->commit_used = used; + spin_unlock(&cache->lock); key.objectid = cache->start; key.type = BTRFS_BLOCK_GROUP_ITEM_KEY; @@ -2776,7 +2796,7 @@ static int update_block_group_item(struct btrfs_trans_handle *trans, leaf = path->nodes[0]; bi = btrfs_item_ptr_offset(leaf, path->slots[0]); - btrfs_set_stack_block_group_used(&bgi, cache->used); + btrfs_set_stack_block_group_used(&bgi, used); btrfs_set_stack_block_group_chunk_objectid(&bgi, cache->global_root_id); btrfs_set_stack_block_group_flags(&bgi, cache->flags); @@ -2784,6 +2804,12 @@ static int update_block_group_item(struct btrfs_trans_handle *trans, btrfs_mark_buffer_dirty(leaf); fail: btrfs_release_path(path); + /* We didn't update the block group item, need to revert @commit_used. */ + if (ret < 0) { + spin_lock(&cache->lock); + cache->commit_used = old_commit_used; + spin_unlock(&cache->lock); + } return ret; } diff --git a/fs/btrfs/block-group.h b/fs/btrfs/block-group.h index 39e79bed10ae..6c970a486b68 100644 --- a/fs/btrfs/block-group.h +++ b/fs/btrfs/block-group.h @@ -100,6 +100,12 @@ struct btrfs_block_group { u64 global_root_id; /* + * The last committed used bytes of this block group, if the above @used + * is still the same as @commit_used, we don't need to update block + * group item of this block group. + */ + u64 commit_used; + /* * If the free space extent count exceeds this number, convert the block * group to bitmaps. */ |