[PATCH] ecryptfs: lower root result must be adirectory

- Currently after path_lookup succeed we dot't have any guarantie what
  it is DIR. This must be explicitly demanded.
- path_lookup can't return negative dentry, So inode check is useless.

Signed-off-by: Dmitriy Monakhov <dmonakhov@openvz.org>
Acked-by: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/ecryptfs/main.c

@@ -484,18 +484,12 @@ static int ecryptfs_read_super(struct super_block *sb, const char *dev_name)
 	struct vfsmount *lower_mnt;
 
 	memset(&nd, 0, sizeof(struct nameidata));
-	rc = path_lookup(dev_name, LOOKUP_FOLLOW, &nd);
+	rc = path_lookup(dev_name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &nd);
 	if (rc) {
 		ecryptfs_printk(KERN_WARNING, "path_lookup() failed\n");
 		goto out;
 	}
 	lower_root = nd.dentry;
-	if (!lower_root->d_inode) {
-		ecryptfs_printk(KERN_WARNING,
-				"No directory to interpose on\n");
-		rc = -ENOENT;
-		goto out_free;
-	}
 	lower_mnt = nd.mnt;
 	ecryptfs_set_superblock_lower(sb, lower_root->d_sb);
 	sb->s_maxbytes = lower_root->d_sb->s_maxbytes;