报错：
[root@centos21 space]# resize2fs /dev/centos/root resize2fs 1.42.9 (28-Dec-2013) resize2fs: Bad magic number in super-block while trying to open /dev/centos/root Couldn't find valid filesystem superblock.
解决办法：
xfs文件系统需要使用xfs命令
[root@centos21 space]# xfs
xfs_admin xfsdump xfs_growfs xfs_logprint xfs_ncheck xfs_rtcp
xfs_bmap xfs_estimate xfs_info xfs_mdrestore xfs_quota
xfs_copy xfs_freeze xfsinvutil xfs_metadump xfs_repair
xfs_db xfs_fsr xfs_io xfs_mkfile xfsrestore
[root@centos21 space]# xfs_growfs /dev/mapper/centos-root