XFS problems post RAID crash

[Lonni J Friedman]

You never stated what kernel version you were using.  Anyway, if
you're able to mount the filesystem read only, then I'm unclear why
you can't make a copy of that data and use that?

On Wed, Jul 27, 2011 at 2:20 PM, sysadmin <sysadmin at insinc.com> wrote:
>
> Hey all,
>
> I had an Linux MD RAID 5 array that had 2 drives go offline due to bad
> sectors (no data scrubbing was being performed).
>
> I've managed to rebuild the array and can mount the XFS file system RO. Some
> of the files are missing/corrupt but I have managed to transfer many of them
> off to another system.
>
> Only trouble now is when I mount the file system RW I get problems such as
> "cannot allocate memory" doing an ls on a directory and other such strange
> problems.
>
> Running xfs_repair gives:
>
>  10:09 root at servername:~# xfs_repair /dev/md5
>  Phase 1 - find and verify superblock...
>  Phase 2 - using internal log
>         - zero log...
>         - scan filesystem freespace and inode maps...
>  bad magic # 0x20000000 in btbno block 5/1098
>  bad magic # 0 in btcnt block 6/5518
>  expected level 1 got 0 in btcnt block 6/5518
>  bad magic # 0 in btcnt block 7/5129
>  expected level 1 got 0 in btcnt block 7/5129
>  bad magic # 0x6e73745f in btbno block 8/218842
>  expected level 0 got 2354 in btbno block 8/218842
>  bad magic # 0x33340933 in btcnt block 8/218847
>  expected level 0 got 13104 in btcnt block 8/218847
>  bad magic # 0x28717476 in btbno block 10/13130259
>  expected level 1 got 25970 in btbno block 10/13130259
>  bad magic # 0x2f000000 in btbno block 13/31016602
>  bad magic # 0 in btcnt block 14/13717213
>  expected level 1 got 0 in btcnt block 14/13717213
>  bad magic # 0xf0980300 in btcnt block 15/1358720
>  bad magic # 0x2e323032 in btbno block 17/28998874
>  expected level 0 got 11825 in btbno block 17/28998874
>  bad magic # 0x36332e31 in btcnt block 17/28998875
>  expected level 0 got 14137 in btcnt block 17/28998875
>  bad magic # 0 in btbno block 19/91721
>  block (22,5084) multiply claimed by bno space tree, state - 2
>  block (22,5085) multiply claimed by bno space tree, state - 2
>  bcnt freespace btree block claimed (state 1), agno 23, bno 21801, suspect 0
>  bad magic # 0x2d313509 in btbno block 24/17051
>  expected level 1 got 12848 in btbno block 24/17051
>  block (25,22903) multiply claimed by bno space tree, state - 7
>  block (25,23312) multiply claimed by bno space tree, state - 2
>  block (25,23313) multiply claimed by bno space tree, state - 2
>  block (25,23314) multiply claimed by bno space tree, state - 2
>  block (25,23315) multiply claimed by bno space tree, state - 2
>  block (25,23316) multiply claimed by bno space tree, state - 2
>  block (25,23317) multiply claimed by bno space tree, state - 2
>  bno freespace btree block claimed (state 1), agno 25, bno 22902, suspect 0
>  bcnt freespace btree block claimed (state 1), agno 25, bno 23400, suspect 0
>  bad magic # 0x41425442 in btcnt block 27/1293
>  expected level 1 got 0 in btcnt block 27/1293
>  bad magic # 0x2000000 in btcnt block 27/16922334
>
> No matter the xfs_repair flags I use (even -d with the server booted in
> single user mode) the repair hangs at this point i.e. with this exact bad
> magic line:
>
>  bad magic # 0x2000000 in btcnt block 27/16922334
>
> Is there anything I can do to recover this file system ? Obviously a full
> recovery would be ideal but given the RAID crash likely impossible. At this
> stage I'd be happy if I could just get the file system to run on whatever
> data it's managed to retain. If I have to reformat and transfer data back
> onto the system the transfer will take days.
>
> I've hunted around on the web and found people having similar issues but not
> quite the same e.g. :
>
>  http://old.nabble.com/bad-magic-and-dubious-inode-td8785248.html#a8785248
>
> Any help appreciated.

-- 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
L. Friedman                                    netllama at gmail.com
LlamaLand                       https://netllama.linux-sxs.org