On Mon, May 23, 2011 at 02:39:39PM -0700, Nuno Subtil wrote:
> I have an MD RAID-1 array with two SATA drives, formatted as XFS.
Hi Nuno. it is probably best to say this at the start, too:
> This is on an ARM system running kernel 2.6.39.
So we know what platform this is occurring on.
> Occasionally, doing an umount followed by a mount causes the mount to
> fail with errors that strongly suggest some sort of filesystem
> corruption (usually 'bad clientid' with a seemingly arbitrary ID, but
> occasionally invalid log errors as well).
So reading back the journal is getting bad data?
>
> The one thing in common among all these failures is that they require
> xfs_repair -L to recover from. This has already caused a few
> lost+found entries (and data loss on recently written files). I
> originally noticed this bug because of mount failures at boot, but
> I've managed to repro it reliably with this script:
Yup, that's normal with recovery errors.
> while true; do
> mount /store
> (cd /store && tar xf test.tar)
> umount /store
> mount /store
> rm -rf /store/test-data
> umount /store
> done
Ok, so there's nothing here that actually says it's an unmount
error. More likely it is a vmap problem in log recovery resulting in
aliasing or some other stale data appearing in the buffer pages.
Can you add a 'xfs_logprint -t <device>' after the umount? You
should always see something like this telling you the log is clean:
$ xfs_logprint -t /dev/vdb
xfs_logprint:
data device: 0xfd10
log device: 0xfd10 daddr: 11534368 length: 20480
log tail: 51 head: 51 state: <CLEAN>
If the log is not clean on an unmount, then you may have an unmount
problem. If it is clean when the recovery error occurs, then it's
almost certainly a problem with you platform not implementing vmap
cache flushing correctly, not an XFS problem.
> I'm not entirely sure that this is XFS-specific, but the same script
> does run successfully overnight on the same MD array with ext3 on it.
ext3 doesn't use vmapped buffers at all, so won't show such a
proble,.
> Has something like this been seen before?
Every so often on ARM, MIPS, etc platforms that have virtually
indexed caches.
Cheers,
Dave.
--
Dave Chinner
david@xxxxxxxxxxxxx
_______________________________________________
xfs mailing list
xfs@xxxxxxxxxxx
http://oss.sgi.com/mailman/listinfo/xfs
