Re: WARNING: at fs/buffer.c:1186 mark_buffer_dirty+0x51/0x66()

[Nick Piggin <nickpiggin@yahoo.com.au>]

On Saturday 01 November 2008 05:11, Vladislav Bolkhovitin wrote:
> Nick Piggin wrote:
> > On Wednesday 29 October 2008 06:38, Vladislav Bolkhovitin wrote:
> >> Nick Piggin wrote:
> >>> On Saturday 25 October 2008 03:10, Vladislav Bolkhovitin wrote:
> >>>> Hi,
> >>>>
> >>>> During recent debugging session of my SCSI target SCST
> >>>> (http://scst.sf.net) I noticed many
> >>>>
> >>>> WARNING: at fs/buffer.c:1186 mark_buffer_dirty+0x51/0x66()
> >>>>
> >>>> messages in kernel log on the initiator. I attached the full log of
> >>>> several of them.
> >>>>
> >>>> My target was buggy and I was working on fixing it, but I suppose
> >>>> Linux should handle such failures more gracefully. In all the cases
> >>>> the target had one type of failure: it "ate" a SCSI command and never
> >>>> returned result of it.
> >>>
> >>> Right. This is one of the warnings I see in my fault-injection testing.
> >>> It is fixed by my patch to clean up and improve the page and buffer
> >>> error handling in the vm/fs.
> >>
> >> Can you specify which patch you referring? Is it in 2.6.27?
> >
> > It's just an RFC at the moment which I posted to fsdevel. Not in 2.6.27.
>
> I see. I'm looking forward to see it in 2.6.28 or .29. This is really a
> needed work.

Hopefully. Unfortunately it doesn't exactly make the filesystems
themselves more robust against failure. That needs to be done on
a case by case basis.


> BTW, have you even seen in your fault-injection testing that after
> receiving a failure from a SCSI device during heavy load ext3 file
> system mounted on it gets corrupted and journal replay on remount
> doesn't repair it, only manual e2fsck helps? I've many times seen that,
> including cases when the target was remaining up and fully functional.
> See, e.g., "MOANING MODE ON" part in
> http://marc.info/?l=linux-scsi&m=121932252324432&w=2. I haven't checked
> that case since then, although I see such corruptions quite often. But
> in all them I can't so clearly say that it isn't a target's failure.

I haven't seen that, but I'm not exactly testing for filesystem
robustness to errors, but more of core vm/fs layer robustness, so
I'm mainly trying to inject errors into data portion of inodes.

I think the ext3 development list should be interested in your
report.

Thanks,
Nick