Re: XFS corruption after power surge/outage

[Eric Sandeen <sandeen@sandeen.net>]

On 2/12/24 3:06 PM, Dave Chinner wrote:
> That has the XFS_SB_FEAT_INCOMPAT_NEEDSREPAIR bit set...
> 
>> I wonder if that is because I tried a xfs_repair with a newer version...
> .... which is a result of xfs_repair 6.5.0 crashing mid way through
> repair of the filesystem. Your kernel is too old to recognise the
> NEEDSREPAIR bit. You can clear it with xfs_db like this:
> 
> Run this to get the current field value:
> 
> # xfs_db -c "sb 0" -c "p features_incompat" <dev>
> 
> Then subtract 0x10 from the value returned and run:
> 
> # xfs_db -c "sb 0" -c "write features_incompat <val>" <dev>
> 
> But that won't get you too far - the filesystem is still corrupt and
> inconsistent. By blowing away the log with xfs_repair before
> actually determining if the problem was caused by a RAID array
> issue, you've essentially forced yourself into a filesystem recovery
> situation.

Everything Dave said, yes. Depending on how bad the corruption is, you
*might* be able to do a readonly or readonly/norecovery mount and scrape
some data out.

Ideally the first thing to do would be to make a 1:1 dd image of the
device as a safe backup, but I understand it's 300T ...

-Eric