修复磁盘超级块

[root@localhost ~]# dd if=/dev/zero of=/dev/sdb1 bs=2M count=1
1+0 records in
1+0 records out
2097152 bytes (2.1 MB) copied, 0.0121084 s, 173 MB/s
[root@localhost ~]# blkid
/dev/sda1: UUID="78340f63-ea0d-4eca-a64d-807316c29ec9" TYPE="xfs"
/dev/sda2: UUID="3hqYtD-lKxZ-BxlK-tlox-SFOa-88pS-4meosd" TYPE="LVM2_member"
/dev/sdb1: PARTLABEL="dp1" PARTUUID="8c9692e3-9572-45b0-85d2-aa759fb1f39c"
/dev/sr0: UUID="2016-12-05-23-44-06-00" LABEL="CentOS 7 x86_64" TYPE="iso9660" PTTYPE="dos"
/dev/mapper/cl-root: UUID="d8352899-91cc-4be2-865a-0d11e4e0400d" TYPE="xfs"
/dev/mapper/cl-swap: UUID="d364b0db-7f72-42dc-bda8-1b1f99bc4a65" TYPE="swap"
/dev/sdb2: UUID="712bdda8-2675-491c-8bd7-4433b5edc78e" TYPE="ext4" PARTLABEL="dp2" PARTUUID="0247c597-e8e9-4427-8630-6358b8682c36"
[root@localhost ~]# mount /dev/sdb1 /mnt
mount: /dev/sdb1 is write-protected, mounting read-only
mount: unknown filesystem type '(null)'
[root@localhost ~]# mke2fs -n /dev/sdb1
mke2fs 1.42.9 (28-Dec-2013)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
610800 inodes, 2441402 blocks
122070 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=2503999488
75 block groups
32768 blocks per group, 32768 fragments per group
8144 inodes per group
Superblock backups stored on blocks:
    32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632

[root@localhost ~]# e2fsck -b 32768 /dev/sdb1
e2fsck 1.42.9 (28-Dec-2013)
/dev/sdb1 was not cleanly unmounted, check forced.
Resize inode not valid.  Recreate<y>? yes
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information
Free blocks count wrong for group #0 (23558, counted=23559).
Fix<y>? yes
Free blocks count wrong (2361059, counted=2361060).
Fix<y>? yes

/dev/sdb1: ***** FILE SYSTEM WAS MODIFIED *****
/dev/sdb1: 11/610800 files (0.0% non-contiguous), 80342/2441402 blocks
[root@localhost ~]# mount /dev/sdb1 /mnt
[root@localhost ~]# ls /mnt
lost+found