From: Shlomi Fish <shlomif@iglu.org.il>
To: Nathan Scott <nathans@sgi.com>
Subject: Re: XFS Mount Hangs the Partition (on latest kernel + many old 2.6.x ones)
Date: Thu, 8 Dec 2005 17:55:57 +0200
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On Wednesday 07 December 2005 22:55, Nathan Scott wrote:
> On Wed, Dec 07, 2005 at 01:57:38PM +0200, Shlomi Fish wrote:
> > Hi all!
>
> Hi there,

Hi Mr. Scott (and all)!

>
> > (Please CC me on replies)
> >
> > I encountered a problem with the Linux kernel handling of XFS, in which
> > attempting to mount a certain XFS partition (but not a different one on
> > the same hard-disk) caused the mount process to hang, and all other
> > XFS-aware apps (like "xfs_check" or "xfs_repair") to hang too. However,
> > running xfs_check
> > or xfs_repair before the first mount (after a reboot) worked, and
> > eventually resolved this problem.
> >
> > I blogged about it (relatively incoherently) here:
> >
> > http://www.livejournal.com/~shlomif/7182.html?mode=reply
> > http://www.livejournal.com/~shlomif/7547.html?mode=reply
>
> Unfortunately there's not much information here in your mail or
> there that would help us to analyse this further.  If you see this
> behaviour again could you:
> - get sysrq-t information for all hung processes, esp. mount;
> - send xfs_info output for the filesystem in question;
> - dump the log (xfs_logprint -C) and send it to us.

Sure. But in what order should I do all that?

>
> > It all happened after I detected some problems on my Mandriva 2006 system
> > (that was using kernel 2.4.15-rc2 from Linus), and then rebooted twice,
> > thinking something went wrong. Then a loadlin-booted kernel was unable to
> > load the kernel.
> >
> > Knoppix ran fine, but it also hang up on attempting to mount the XFS
> > partition. It used a much older kernel. I then tried to boot Kubuntu
> > (which was on another XFS partition on the same disk) and it booted fine.
> > Still, it was unable to mount the partition. (It too had an older
> > kernel).
> >
> > After I compiled a 2.6.14.3 kernel, and booted Kubuntu with it, it again
> > could not mount the XFS partition, and after doing that xfs_check and
> > xfs_repair both hanged up as well. After a reboot, I tried running
> > xfs_check
>
> This was probably caused by the block device being held open
> exclusively by the stuck mount process.

I see.

>
> > right away on that partition and it worked. So I ran xfs_repair, and
> > after it finished, tried to mount the partition it worked. Then Mandriva
> > booted fine.
> >
> > I did not had any problems since then (I have an uptime of 11 days now
> > using kernel 2.6.14.3), and so it doesn't seem like a hard disk problem.
> > Something using kernel 2.6.15-rc2 caused the XFS partition to become
> > defected, and worse - something in all the kernels starting from that of
> > the first official Kubuntu release, (or the Knoppix I had), caused an
> > attempt to mount the Mandriva partition to hang the process, and
> > subsequent accesses to the partition by xfs_check and xfs_repair to fail
> > as well.
> >
> > I can no longer reproduce the problem, but it might be worth going over
> > the code. If it helps I can privately send a dump of the first
> > 131,072,000 bytes of the XFS partition to someone trustworthy.
>
> Thats unlikely to help now - repair will have wiped your log clean,
> so all evidence of the problem will be gone.

Yes. I thought one can try looking in the XFS mounting code for possible bugs.

Regards,

	Shlomi Fish

---------------------------------------------------------------------
Shlomi Fish      shlomif@iglu.org.il
Homepage:        http://www.shlomifish.org/

95% of the programmers consider 95% of the code they did not write, in the
bottom 5%.
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