Commit 316fb1b3 authored by robbieko's avatar robbieko Committed by David Sterba
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btrfs: fix incorrect return value after changing leaf in lookup_extent_data_ref() 



After commit 1618aa3c ("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: 1618aa3c ("btrfs: simplify return variables in lookup_extent_data_ref()")
CC: stable@vger.kernel.org # 6.12+
Reviewed-by: default avatarFilipe Manana <fdmanana@suse.com>
Signed-off-by: default avatarrobbieko <robbieko@synology.com>
Signed-off-by: default avatarFilipe Manana <fdmanana@suse.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 1c37d896

fs/btrfs/extent-tree.c

+1 −1
Original line number Diff line number Diff line
@@ -495,7 +495,7 @@ 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);