fsck -fy /dev/sda1
dumpe2fs /dev/sda1|grep superblock查看 备份的superblock
root@Defcon:/tmp# dumpe2fs /dev/sda1|grep super
dumpe2fs 1.42 (29-Nov-2011)
Filesystem features: ext_attr resize_inode dir_index filetype sparse_super
Primary superblock at 1, Group descriptors at 2-2
Backup superblock at 8193, Group descriptors at 8194-8194
Backup superblock at 24577, Group descriptors at 24578-24578
Backup superblock at 40961, Group descriptors at 40962-40962
Backup superblock at 57345, Group descriptors at 57346-57346
Backup superblock at 73729, Group descriptors at 73730-73730
Backup superblock at 204801, Group descriptors at 204802-204802
Backup superblock at 221185, Group descriptors at 221186-221186
然后执行 fsck -b 8193 /dev/sda1,如果成功，尝试mount 系统，如果失败，继续使用下一个备份superblock
mount sb=8193 /dev/sda1 /mnt
如果以上步骤都失败，需要用dd 备份坏掉的磁盘到新的硬盘上
dd conv=noerror if=/dev/sda of=/mnt/recovery/sdap_w_picpath.dd
然后执行
fsck /mnt/recovery/sdap_w_picpath.dd
如果是一个单独的分区，可以这样
mount -o loop /mnt/recovery/sdap_w_picpath.dd /mnt/sdap_w_picpath
如果是多个分区中的一个坏掉，可以这样
fdisk -lu /mnt/recovery/sdap_w_picpath.dd
如果是第二个分区柱面从80300开始，单位是512bit，那么总共是80300×512=4113600bit
那就要这样执行
mount -o loop,offset=41113600 /mnt/recover/sdap_w_picpath.raw /mnt/sdap_w_picpath
然后写一个新磁盘
dd if=/mnt/recovery/sdap_w_picpath.raw of=/dev/sdb
