This is a note to let you know that I've just added the patch titled
btrfs: export: handle invalid inode or root reference in btrfs_get_parent()
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
btrfs-export-handle-invalid-inode-or-root-reference-.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 93d2be30751e74c97f2a3d93c7ed5116c9664a50
Author: David Sterba <dsterba@xxxxxxxx>
Date: Fri Jan 19 21:19:18 2024 +0100
btrfs: export: handle invalid inode or root reference in btrfs_get_parent()
[ Upstream commit 26b66d1d366a375745755ca7365f67110bbf6bd5 ]
The get_parent handler looks up a parent of a given dentry, this can be
either a subvolume or a directory. The search is set up with offset -1
but it's never expected to find such item, as it would break allowed
range of inode number or a root id. This means it's a corruption (ext4
also returns this error code).
Reviewed-by: Josef Bacik <josef@xxxxxxxxxxxxxx>
Reviewed-by: Anand Jain <anand.jain@xxxxxxxxxx>
Signed-off-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/btrfs/export.c b/fs/btrfs/export.c
index ecc33e3a3c063..01e9a5afc33bf 100644
--- a/fs/btrfs/export.c
+++ b/fs/btrfs/export.c
@@ -182,8 +182,15 @@ struct dentry *btrfs_get_parent(struct dentry *child)
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
if (ret < 0)
goto fail;
+ if (ret == 0) {
+ /*
+ * Key with offset of -1 found, there would have to exist an
+ * inode with such number or a root with such id.
+ */
+ ret = -EUCLEAN;
+ goto fail;
+ }
- BUG_ON(ret == 0); /* Key with offset of -1 found */
if (path->slots[0] == 0) {
ret = -ENOENT;
goto fail;
