[PATCH v2] ovl: replace dget/dput with d_drop in ovl_cleanup()

[Miklos Szeredi <mszeredi@redhat.com>]

The reason for the dget/dput pair was to force the upperdentry to be
dropped from the cache instead of turning it negative and keeping it
cached.

Simpler and cleaner way to achieve the same effect is to just drop the
dentry after unlink/rmdir if it was turned negative.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
---
v2:
 - use d_drop()

 fs/overlayfs/dir.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
index ab65e98a1def..c7548c2bbc12 100644
--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -28,12 +28,14 @@ int ovl_cleanup(struct ovl_fs *ofs, struct inode *wdir, struct dentry *wdentry)
 {
 	int err;
 
-	dget(wdentry);
 	if (d_is_dir(wdentry))
 		err = ovl_do_rmdir(ofs, wdir, wdentry);
 	else
 		err = ovl_do_unlink(ofs, wdir, wdentry);
-	dput(wdentry);
+
+	/* A cached negative upper dentry is generally not useful, so drop it. */
+	if (d_is_negative(wdentry))
+		d_drop(wdentry);
 
 	if (err) {
 		pr_err("cleanup of '%pd2' failed (%i)\n",
-- 
2.47.0