centos7.2 error: Input/output error - centos

Question

Our server runs Centos 7.2, today it seems to fail.
When I connect to it using ssh, I get
-bash: /share/home/MGI/.bash_profile: Input/output error
and log in like this:
-bash-4.2$
ls failed,
ls: cannot open directory .: Input/output error
Trying to edit a file with vi will get Permission denied
but cd and pwd is still of use.
I googled it and found the disk might be damaged, then I tried some suggestions. mount give me this:
sysfs on /sys type sysfs (rw,nosuid,nodev,noexec,relatime)
proc on /proc type proc (rw,nosuid,nodev,noexec,relatime)
devtmpfs on /dev type devtmpfs (rw,nosuid,size=32831312k,nr_inodes=8207828,mode=755)
securityfs on /sys/kernel/security type securityfs (rw,nosuid,nodev,noexec,relatime)
tmpfs on /dev/shm type tmpfs (rw,nosuid,nodev)
devpts on /dev/pts type devpts (rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=000)
tmpfs on /run type tmpfs (rw,nosuid,nodev,mode=755)
tmpfs on /sys/fs/cgroup type tmpfs (ro,nosuid,nodev,noexec,mode=755)
cgroup on /sys/fs/cgroup/systemd type cgroup (rw,nosuid,nodev,noexec,relatime,xattr,release_agent=/usr/lib/systemd/systemd-cgroups-agent,name=systemd)
pstore on /sys/fs/pstore type pstore (rw,nosuid,nodev,noexec,relatime)
cgroup on /sys/fs/cgroup/memory type cgroup (rw,nosuid,nodev,noexec,relatime,memory)
cgroup on /sys/fs/cgroup/devices type cgroup (rw,nosuid,nodev,noexec,relatime,devices)
cgroup on /sys/fs/cgroup/cpuset type cgroup (rw,nosuid,nodev,noexec,relatime,cpuset)
cgroup on /sys/fs/cgroup/cpu,cpuacct type cgroup (rw,nosuid,nodev,noexec,relatime,cpuacct,cpu)
cgroup on /sys/fs/cgroup/hugetlb type cgroup (rw,nosuid,nodev,noexec,relatime,hugetlb)
cgroup on /sys/fs/cgroup/perf_event type cgroup (rw,nosuid,nodev,noexec,relatime,perf_event)
cgroup on /sys/fs/cgroup/net_cls type cgroup (rw,nosuid,nodev,noexec,relatime,net_cls)
cgroup on /sys/fs/cgroup/freezer type cgroup (rw,nosuid,nodev,noexec,relatime,freezer)
cgroup on /sys/fs/cgroup/blkio type cgroup (rw,nosuid,nodev,noexec,relatime,blkio)
configfs on /sys/kernel/config type configfs (rw,relatime)
/dev/md126p2 on / type ext4 (rw,relatime,data=ordered)
mqueue on /dev/mqueue type mqueue (rw,relatime)
hugetlbfs on /dev/hugepages type hugetlbfs (rw,relatime)
debugfs on /sys/kernel/debug type debugfs (rw,relatime)
systemd-1 on /proc/sys/fs/binfmt_misc type autofs (rw,relatime,fd=35,pgrp=1,timeout=300,minproto=5,maxproto=5,direct)
sunrpc on /var/lib/nfs/rpc_pipefs type rpc_pipefs (rw,relatime)
nfsd on /proc/fs/nfsd type nfsd (rw,relatime)
/dev/mapper/mpatha1 on /share type xfs (rw,relatime,attr2,inode64,noquota)
/dev/md126p1 on /boot type ext4 (rw,relatime,data=ordered)
fusectl on /sys/fs/fuse/connections type fusectl (rw,relatime)
tmpfs on /run/user/1038 type tmpfs (rw,nosuid,nodev,relatime,size=6569364k,mode=700,uid=1038,gid=1039)
tmpfs on /run/user/1016 type tmpfs (rw,nosuid,nodev,relatime,size=6569364k,mode=700,uid=1016,gid=1016)
tmpfs on /run/user/1008 type tmpfs (rw,nosuid,nodev,relatime,size=6569364k,mode=700,uid=1008,gid=1008)
tmpfs on /run/user/0 type tmpfs (rw,nosuid,nodev,relatime,size=6569364k,mode=700)
gvfsd-fuse on /run/user/0/gvfs type fuse.gvfsd-fuse (rw,nosuid,nodev,relatime,user_id=0,group_id=0)
tmpfs on /run/user/1019 type tmpfs (rw,nosuid,nodev,relatime,size=6569364k,mode=700,uid=1019,gid=1020)
dmesg gives a long output and these two lines appear frequently:
XFS (dm-1): xfs_log_force: error -5 returned.
scsi 11:0:0:0: alua: rtpg failed with 8000002
What should I do now to find out what is actually going wrong and how can I fix it? Many thanks.