btrfs: use error code returned by btrfs_read_fs_root_no_name in search ioctl

btrfs_read_fs_root_no_name() may return ERR_PTR(-ENOENT) or
ERR_PTR(-ENOMEM) and therefore search_ioctl() and
btrfs_search_path_in_tree() should use PTR_ERR() instead of -ENOENT,
which all other callers of btrfs_read_fs_root_no_name() do.

Drop the error message as it would be confusing, the caller of ioctl
will likely interpret the error code and not look into the syslog.

Signed-off-by: Tomohiro Misono <misono.tomohiro@jp.fujitsu.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/ioctl.c

@@ -2155,7 +2155,7 @@ static noinline int search_ioctl(struct inode *inode,
 		root = btrfs_read_fs_root_no_name(info, &key);
 		if (IS_ERR(root)) {
 			btrfs_free_path(path);
-			return -ENOENT;
+			return PTR_ERR(root);
 		}
 	}
 
@@ -2289,8 +2289,7 @@ static noinline int btrfs_search_path_in_tree(struct btrfs_fs_info *info,
 	key.offset = (u64)-1;
 	root = btrfs_read_fs_root_no_name(info, &key);
 	if (IS_ERR(root)) {
-		btrfs_err(info, "could not find root %llu", tree_id);
+		ret = PTR_ERR(root);
-		ret = -ENOENT;
 		goto out;
 	}