From: Erez Zadok <ezk@cs.sunysb.edu>
Date: Tue, 12 Aug 2014 00:49:59 +0000 (-0400)
Subject: Unionfs: fix d_revalidate for corner case
X-Git-Url: https://git.fsl.cs.sunysb.edu/?a=commitdiff_plain;h=9227115777cbe85b80cef83f5be6e894340a466a;p=unionfs-3.15.y.git

Unionfs: fix d_revalidate for corner case

In some cases, lower_dentry may goes to NULL.  Return 0 here to mark it
as invalid dentry.

Signed-off-by: Erez Zadok <ezk@cs.sunysb.edu>
Signed-off-by: Mengyang Li <li.mengyang@stonybrook.edu>
---

diff --git a/fs/unionfs/dentry.c b/fs/unionfs/dentry.c
index a10c4fdb40d..318b3d53e67 100644
--- a/fs/unionfs/dentry.c
+++ b/fs/unionfs/dentry.c
@@ -312,6 +312,10 @@ static int unionfs_d_revalidate(struct dentry *dentry, unsigned int flags)
 	unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
 
 	lower_dentry = unionfs_lower_dentry(dentry);
+	if (!lower_dentry) {
+		err = 0;
+		goto out;
+	}
 	if (!(lower_dentry->d_flags & DCACHE_OP_REVALIDATE))
 		goto out;