eCryptfs: Clear i_nlink in rmdir

eCryptfs wasn't clearing the eCryptfs inode's i_nlink after a successful
vfs_rmdir() on the lower directory. This resulted in the inode evict and
destroy paths to be missed.

https://bugs.launchpad.net/ecryptfs/+bug/723518

Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
Cc: <stable@kernel.org>
diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
index 4d4cc6a..94ab3c0 100644
--- a/fs/ecryptfs/inode.c
+++ b/fs/ecryptfs/inode.c
@@ -527,6 +527,8 @@
 	dget(lower_dentry);
 	rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry);
 	dput(lower_dentry);
+	if (!rc && dentry->d_inode)
+		clear_nlink(dentry->d_inode);
 	fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
 	dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
 	unlock_dir(lower_dir_dentry);