我有一个包含 3 个磁盘的 raid 5 阵列，使用btrfs（由 raid 提供btrfs）其中一个磁盘已损坏，我通过以下方式更换了磁盘：
btrfs device add /dev/sdc /media/raid/
btrfs device delete missing /media/raid/
这迫使磁盘之间进行重新平衡，之后 FS 就正常了。
重启一次后：
[11152.188020] BTRFS info (device sdb): enabling auto defrag
[11152.188028] BTRFS info (device sdb): disk space caching is enabled
[11152.189762] BTRFS: failed to read chunk tree on sdb
[11152.196224] BTRFS: open_ctree failed
pc ~ # mount -a
mount: wrong fs type, bad option, bad superblock on /dev/sde,
missing codepage or helper program, or other error
syslog在某些情况下，可以在- 尝试
dmesg | tail左右找到有用的信息。
操作系统首先注释掉 中的该行fstab，之后我取消了该行的注释。
LABEL="raid" /media/raid btrfs compress=lzo,noatime,autodefrag
我使用的是 Gentoo Linux，内核 4.0.5。
这里是btrfs fi表演：
Label: 'raid' uuid: 906ed4e3-52c5-4eb7-bd06-4810c0b84902
Total devices 3 FS bytes used 775.29GiB
devid 1 size 931.51GiB used 390.06GiB path /dev/sdb
devid 3 size 931.51GiB used 390.04GiB path /dev/sde
devid 4 size 931.51GiB used 390.03GiB path /dev/sdc
pc / # btrfs-find-root /dev/sdc
Superblock thinks the generation is 1758
Superblock thinks the level is 0
Found tree root at 30818304 gen 1758 level 0
Well block 30457856(gen: 1757 level: 0) seems good, but generation/level doesn't match, want gen: 1758 level: 0
Well block 29753344(gen: 1590 level: 0) seems good, but generation/level doesn't match, want gen: 1758 level: 0
Well block 29507584(gen: 1589 level: 0) seems good, but generation/level doesn't match, want gen: 1758 level: 0
Well block 4243456(gen: 3 level: 0) seems good, but generation/level doesn't match, want gen: 1758 level: 0
Well block 4194304(gen: 2 level: 0) seems good, but generation/level doesn't match, want gen: 1758 level: 0
答案1
您是否尝试使用该选项安装卷recovery？
从man mount：
恢复：如果在安装时发现错误的树根，则启用自动恢复尝试。目前，它会扫描之前几个树根的列表，并尝试使用第一个可读的。
mount -o recovery /dev/sdb /media/raid