diff options
| author | Filipe Manana <fdmanana@suse.com> | 2024-07-08 15:42:45 +0100 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2024-07-11 16:50:54 +0200 |
| commit | 4484940514295b75389f94787f8e179ba6255353 (patch) | |
| tree | 68de671f64cdfaa2309c83e3d76e358acaa481b9 /fs/btrfs/disk-io.c | |
| parent | b3ebb9b7e92a928344a7a2c1f8514474bfa113cf (diff) | |
btrfs: avoid races when tracking progress for extent map shrinking
We store the progress (root and inode numbers) of the extent map shrinker
in fs_info without any synchronization but we can have multiple tasks
calling into the shrinker during memory allocations when there's enough
memory pressure for example.
This can result in a task A reading fs_info->extent_map_shrinker_last_ino
after another task B updates it, and task A reading
fs_info->extent_map_shrinker_last_root before task B updates it, making
task A see an odd state that isn't necessarily harmful but may make it
skip certain inode ranges or do more work than necessary by going over
the same inodes again. These unprotected accesses would also trigger
warnings from tools like KCSAN.
So add a lock to protect access to these progress fields.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs/disk-io.c')
| -rw-r--r-- | fs/btrfs/disk-io.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index 242ada7e47b4..1d93fb02fce2 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -2856,6 +2856,8 @@ static int init_mount_fs_info(struct btrfs_fs_info *fs_info, struct super_block if (ret) return ret; + spin_lock_init(&fs_info->extent_map_shrinker_lock); + ret = percpu_counter_init(&fs_info->dirty_metadata_bytes, 0, GFP_KERNEL); if (ret) return ret; |