今天在进行lvm扩容之后，按照惯例进行 resize2fs 操作，发现报如下错误：

# 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.

检查 /dev/centos/root 文件系统，发现是xfs，如下;

# mount |grep root
/dev/mapper/centos-root on / type xfs (rw,relatime,attr2,inode64,noquota)

xfs的文件系统重新定义大小用如下命令：

# xfs_growfs /dev/mapper/centos-root 
meta-data=/dev/mapper/centos-root isize=256 agcount=4, agsize=3276800 blks
 = sectsz=512 attr=2, projid32bit=1
 = crc=0 finobt=0
data = bsize=4096 blocks=13107200, imaxpct=25
 = sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=0
log =internal bsize=4096 blocks=6400, version=2
 = sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
data blocks changed from 13107200 to 39336960

重新进行df -h查看挂载点，发现大小已经更改。