diff options
| author | Filipe Manana <fdmanana@suse.com> | 2023-01-17 14:21:38 +0300 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2023-02-15 21:38:50 +0300 |
| commit | 4e4488d4efd56951e6c1c0f60f1fc8e0f93b7964 (patch) | |
| tree | 27f8320f6c8f194a26b81d2494ff2a73d0a15623 /fs/btrfs/backref.c | |
| parent | 2b5463fcbdfb24e898916bcae2b1359042d26963 (diff) | |
| download | linux-4e4488d4efd56951e6c1c0f60f1fc8e0f93b7964.tar.xz | |
btrfs: assert commit root semaphore is held when accessing backref cache
During fiemap, when accessing the cache that stores the sharedness of an
extent, we need to either be holding a transaction handle or the commit
root semaphore. I left comments about this in the comment that precedes
store_backref_shared_cache() and lookup_backref_shared_cache(), but have
actually not enforced it through assertions. So assert that the commit
root semaphore is held if we are not holding a transaction handle.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.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/backref.c')
| -rw-r--r-- | fs/btrfs/backref.c | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c index 46851511b661..f846fec08c86 100644 --- a/fs/btrfs/backref.c +++ b/fs/btrfs/backref.c @@ -1252,8 +1252,12 @@ static bool lookup_backref_shared_cache(struct btrfs_backref_share_check_ctx *ct struct btrfs_root *root, u64 bytenr, int level, bool *is_shared) { + const struct btrfs_fs_info *fs_info = root->fs_info; struct btrfs_backref_shared_cache_entry *entry; + if (!current->journal_info) + lockdep_assert_held(&fs_info->commit_root_sem); + if (!ctx->use_path_cache) return false; @@ -1288,7 +1292,7 @@ static bool lookup_backref_shared_cache(struct btrfs_backref_share_check_ctx *ct * could be a snapshot sharing this extent buffer. */ if (entry->is_shared && - entry->gen != btrfs_get_last_root_drop_gen(root->fs_info)) + entry->gen != btrfs_get_last_root_drop_gen(fs_info)) return false; *is_shared = entry->is_shared; @@ -1318,9 +1322,13 @@ static void store_backref_shared_cache(struct btrfs_backref_share_check_ctx *ctx struct btrfs_root *root, u64 bytenr, int level, bool is_shared) { + const struct btrfs_fs_info *fs_info = root->fs_info; struct btrfs_backref_shared_cache_entry *entry; u64 gen; + if (!current->journal_info) + lockdep_assert_held(&fs_info->commit_root_sem); + if (!ctx->use_path_cache) return; @@ -1336,7 +1344,7 @@ static void store_backref_shared_cache(struct btrfs_backref_share_check_ctx *ctx ASSERT(level >= 0); if (is_shared) - gen = btrfs_get_last_root_drop_gen(root->fs_info); + gen = btrfs_get_last_root_drop_gen(fs_info); else gen = btrfs_root_last_snapshot(&root->root_item); |