ovl: fix BUG_ON() in may_delete() when called from ovl_cleanup()

commit 52d5a0c6bd8a89f460243ed937856354f8f253a3 upstream.

If function ovl_instantiate() returns an error, ovl_cleanup will be called
and try to remove newdentry from wdir, but the newdentry has been moved to
udir at this time.  This will causes BUG_ON(victim->d_parent->d_inode !=
dir) in fs/namei.c:may_delete.

Signed-off-by: chenying <chenying.kernel@bytedance.com>
Fixes: 01b39dcc9568 ("ovl: use inode_insert5() to hash a newly created inode")
Link: https://lore.kernel.org/linux-unionfs/e6496a94-a161-dc04-c38a-d2544633acb4@bytedance.com/
Cc: <stable@vger.kernel.org> # v4.18
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
index 25be2ab6ff6cc411a46d4e2df39855c271a70d36..0b4ee1ab25df078921e87fd861de208006782f57 100644 (file)
--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -517,8 +517,10 @@ static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode,
                        goto out_cleanup;
        }
        err = ovl_instantiate(dentry, inode, newdentry, hardlink);
-       if (err)
-               goto out_cleanup;
+       if (err) {
+               ovl_cleanup(udir, newdentry);
+               dput(newdentry);
+       }
 out_dput:
        dput(upper);
 out_unlock: