[PATCH 6.19 16/86] btrfs: fix incorrect return value after changing leaf in lookup_extent_data_ref()

Greg Kroah-Hartman
2026-04-13T16:03:45Z

From: robbieko <robbieko@synology.com>

[ Upstream commit 316fb1b3169efb081d2db910cbbfef445afa03b9 ]

After commit 1618aa3c2e01 ("btrfs: simplify return variables in
lookup_extent_data_ref()"), the err and ret variables were merged into
a single ret variable. However, when btrfs_next_leaf() returns 0
(success), ret is overwritten from -ENOENT to 0. If the first key in
the next leaf does not match (different objectid or type), the function
returns 0 instead of -ENOENT, making the caller believe the lookup
succeeded when it did not. This can lead to operations on the wrong
extent tree item, potentially causing extent tree corruption.

Fix this by returning -ENOENT directly when the key does not match,
instead of relying on the ret variable.

Fixes: 1618aa3c2e01 ("btrfs: simplify return variables in lookup_extent_data_ref()")
CC: stable@vger.kernel.org # 6.12+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: robbieko <robbieko@synology.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/btrfs/extent-tree.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index f2b1bc2107539..f5ca544e35431 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -476,7 +476,7 @@ static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
if (key.objectid != bytenr ||
key.type != BTRFS_EXTENT_DATA_REF_KEY)
- return ret;
+ return -ENOENT;

ref = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_extent_data_ref);
--
2.53.0