[PATCH 01/20] btrfs: handle directory and dentry mismatch in btrfs_may_delete()

David Sterba
2024-01-24T21:18:14Z

The helper btrfs_may_delete() is a copy of generic fs/namei.c:may_delete()
to verify various conditions before deletion. There's a BUG_ON added
before linux.git started, we can turn it to a proper error handling
at least in our local helper. A mistmatch between directory and the
deleted dentry is clearly invalid.

This won't be probably ever hit due to the way how the parameters are
set from the caller btrfs_ioctl_snap_destroy(), using a VFS helper
lookup_one().

Signed-off-by: David Sterba <dsterba@suse.com>
---
fs/btrfs/ioctl.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 3d476decde52..845fdc5f2a99 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -910,7 +910,9 @@ static int btrfs_may_delete(struct mnt_idmap *idmap,
if (d_really_is_negative(victim))
return -ENOENT;

- BUG_ON(d_inode(victim->d_parent) != dir);
+ /* The @victim is not inside @dir. */
+ if (d_inode(victim->d_parent) != dir)
+ return -EINVAL;
audit_inode_child(dir, victim, AUDIT_TYPE_CHILD_DELETE);

error = inode_permission(idmap, dir, MAY_WRITE | MAY_EXEC);
--
2.42.1