diff options
Diffstat (limited to 'fs/btrfs')
| -rw-r--r-- | fs/btrfs/backref.c | 25 | ||||
| -rw-r--r-- | fs/btrfs/backref.h | 1 |
2 files changed, 26 insertions, 0 deletions
diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c index 4e29ccb234c0..4ec18ceb2f21 100644 --- a/fs/btrfs/backref.c +++ b/fs/btrfs/backref.c @@ -1536,6 +1536,9 @@ static bool lookup_backref_shared_cache(struct btrfs_backref_shared_cache *cache { struct btrfs_backref_shared_cache_entry *entry; + if (!cache->use_cache) + return false; + if (WARN_ON_ONCE(level >= BTRFS_MAX_LEVEL)) return false; @@ -1600,6 +1603,9 @@ static void store_backref_shared_cache(struct btrfs_backref_shared_cache *cache, struct btrfs_backref_shared_cache_entry *entry; u64 gen; + if (!cache->use_cache) + return; + if (WARN_ON_ONCE(level >= BTRFS_MAX_LEVEL)) return; @@ -1697,6 +1703,7 @@ int btrfs_is_data_extent_shared(struct btrfs_root *root, u64 inum, u64 bytenr, /* -1 means we are in the bytenr of the data extent. */ level = -1; ULIST_ITER_INIT(&uiter); + cache->use_cache = true; while (1) { bool is_shared; bool cached; @@ -1726,6 +1733,24 @@ int btrfs_is_data_extent_shared(struct btrfs_root *root, u64 inum, u64 bytenr, extent_gen > btrfs_root_last_snapshot(&root->root_item)) break; + /* + * If our data extent was not directly shared (without multiple + * reference items), than it might have a single reference item + * with a count > 1 for the same offset, which means there are 2 + * (or more) file extent items that point to the data extent - + * this happens when a file extent item needs to be split and + * then one item gets moved to another leaf due to a b+tree leaf + * split when inserting some item. In this case the file extent + * items may be located in different leaves and therefore some + * of the leaves may be referenced through shared subtrees while + * others are not. Since our extent buffer cache only works for + * a single path (by far the most common case and simpler to + * deal with), we can not use it if we have multiple leaves + * (which implies multiple paths). + */ + if (level == -1 && tmp->nnodes > 1) + cache->use_cache = false; + if (level >= 0) store_backref_shared_cache(cache, root, bytenr, level, false); diff --git a/fs/btrfs/backref.h b/fs/btrfs/backref.h index 52ae6957b414..8e69584d538d 100644 --- a/fs/btrfs/backref.h +++ b/fs/btrfs/backref.h @@ -29,6 +29,7 @@ struct btrfs_backref_shared_cache { * a given data extent should never exceed the maximum b+tree height. */ struct btrfs_backref_shared_cache_entry entries[BTRFS_MAX_LEVEL]; + bool use_cache; }; typedef int (iterate_extent_inodes_t)(u64 inum, u64 offset, u64 root, |