ovl: fix error for ovl_fill_super()

There are some places should return -EINVAL instead of -ENOMEM in
ovl_fill_super().

[Amir] Consistently set error before checking the error condition.

Signed-off-by: Chengguang Xu <cgxu519@mykernel.net>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

fs/overlayfs/super.c

@@ -1981,6 +1981,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
 	if (!ofs)
 		goto out;
 
+	err = -ENOMEM;
 	ofs->creator_cred = cred = prepare_creds();
 	if (!cred)
 		goto out_err;
@@ -2009,6 +2010,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
 	if (!splitlower)
 		goto out_err;
 
+	err = -EINVAL;
 	numlower = ovl_split_lowerdirs(splitlower);
 	if (numlower > OVL_MAX_STACK) {
 		pr_err("too many lower directories, limit is %d\n",
@@ -2016,6 +2018,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
 		goto out_err;
 	}
 
+	err = -ENOMEM;
 	layers = kcalloc(numlower + 1, sizeof(struct ovl_layer), GFP_KERNEL);
 	if (!layers)
 		goto out_err;
@@ -2042,6 +2045,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
 	if (ofs->config.upperdir) {
 		struct super_block *upper_sb;
 
+		err = -EINVAL;
 		if (!ofs->config.workdir) {
 			pr_err("missing 'workdir'\n");
 			goto out_err;