Re: XFS file system corruption, refuses to mount

[Luciano ES <lucmove@gmail.com>]

On Fri, 2 Aug 2019 18:11:06 -0700, Darrick J. Wong wrote:

> On Fri, Aug 02, 2019 at 09:53:56PM -0300, Luciano ES wrote:
> > I've had this internal disk running for a long time. I had to 
> > disconnect it from the SATA and power plugs for two days. 
> > Now it won't mount. 
> > 
> > mount: wrong fs type, bad option, bad superblock
> > on /dev/mapper/cab3, missing codepage or helper program, or other
> > error In some cases useful info is found in syslog - try
> >        dmesg | tail or so.
> > 
> > I get this in dmesg:
> > 
> > [   30.301450] XFS (dm-1): Mounting V5 Filesystem
> > [   30.426206] XFS (dm-1): Corruption warning: Metadata has LSN
> > (16:367696) ahead of current LSN (16:367520). Please unmount and run
> > xfs_repair (>= v4.3) to resolve.  
> 
> Hm, I think this means the superblock LSN is behind the log LSN, which
> could mean that... software is buggy?  The disk didn't flush its cache
> before it was unplugged?  Something else?
> 
> What kernel & xfsprogs?

Debian 4.9.0-3-amd64, xfsprogs 4.9.0.


> And how did you disconnect it from the power plugs?

I shut down the machine, opened the box's cover and disconnected the 
data and power cables. I used them on the CD/DVD drive, which I never 
use but this time I had to. The hard disk drive remained quiet in its 
bay. Then I shut down the machine and reconnected the cables to the 
hard disk and this problem came up. I also tried another cable and 
another SATA port, to no avail.


> > [   30.426209] XFS (dm-1): log mount/recovery failed: error -22
> > [   30.426310] XFS (dm-1): log mount failed
> > 
> > Note that the entire disk is encrypted with cryptsetup/LUKS, 
> > which is working fine. Wrong passwords fail. The right password 
> > opens it. But then it refuses to mount.
> > 
> > This has been happening a lot to me with XFS file systems. 
> > Why is this happening?
> > 
> > Is there something I can do to recover the data?  
> 
> Try xfs_repair -n to see what it would do if you ran repair?

I tried and got this output:


Phase 1 - find and verify superblock...
bad primary superblock - bad magic number !!!

attempting to find secondary superblock...


and it's been printing an endless stream of dots for a very long 
time. I'm about to go to bed and let this running overnight. 
It looks like it has a long way to go.

-- 
Luciano ES
>>