Btrfs: reserve metadata space in btrfs_ioctl_setflags()

Check and reserve space for btrfs_update_inode().
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>

fs/btrfs/ioctl.c

@@ -254,7 +254,7 @@ static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
 		ip->flags &= ~(BTRFS_INODE_COMPRESS | BTRFS_INODE_NOCOMPRESS);
 	}
 
-	trans = btrfs_join_transaction(root);
+	trans = btrfs_start_transaction(root, 1);
 	if (IS_ERR(trans)) {
 		ret = PTR_ERR(trans);
 		goto out_drop;