ext4: Fix potential memory leak in ext4_fill_super

Under heavy memory pressure we may hit out of memory
situation and as result kstrdup'ed options will not be
freed. Fix it.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

fs/ext4/super.c

@@ -2550,7 +2550,7 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 	struct inode *root;
 	char *cp;
 	const char *descr;
-	int ret = -EINVAL;
+	int ret = -ENOMEM;
 	int blocksize;
 	unsigned int db_count;
 	unsigned int i;
@@ -2561,13 +2561,13 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 
 	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 	if (!sbi)
-		return -ENOMEM;
+		goto out_free_orig;
 
 	sbi->s_blockgroup_lock =
 		kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL);
 	if (!sbi->s_blockgroup_lock) {
 		kfree(sbi);
-		return -ENOMEM;
+		goto out_free_orig;
 	}
 	sb->s_fs_info = sbi;
 	sbi->s_mount_opt = 0;
@@ -2584,6 +2584,7 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 	for (cp = sb->s_id; (cp = strchr(cp, '/'));)
 		*cp = '!';
 
+	ret = -EINVAL;
 	blocksize = sb_min_blocksize(sb, EXT4_MIN_BLOCK_SIZE);
 	if (!blocksize) {
 		ext4_msg(sb, KERN_ERR, "unable to set blocksize");
@@ -3190,6 +3191,7 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 	kfree(sbi->s_blockgroup_lock);
 	kfree(sbi);
 	lock_kernel();
+out_free_orig:
 	kfree(orig_data);
 	return ret;
 }