Btrfs: remove negative dentry when deleting subvolumne

The use of btrfs_dentry_delete is removing dentries from the
dcache when deleting subvolumne. btrfs_dentry_delete ignores
negative dentries. This is incorrect since if we don't remove
the negative dentry, its parent dentry can't be removed.

Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 7 insertions, 5 deletions

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index ccc4f1121210..d3585cb6483c 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -3629,12 +3629,14 @@ static int btrfs_dentry_delete(struct dentry *dentry)
 {
         struct btrfs_root *root;
 
-        if (!dentry->d_inode)
-                return 0;
+        if (!dentry->d_inode && !IS_ROOT(dentry))
+                dentry = dentry->d_parent;
 
-        root = BTRFS_I(dentry->d_inode)->root;
-        if (btrfs_root_refs(&root->root_item) == 0)
-                return 1;
+        if (dentry->d_inode) {
+                root = BTRFS_I(dentry->d_inode)->root;
+                if (btrfs_root_refs(&root->root_item) == 0)
+                        return 1;
+        }
         return 0;
 }