From: Neil Brown <neilb@suse.de>
To: Francois Barre <francois.barre@gmail.com>
Cc: linux-raid <linux-raid@vger.kernel.org>
Subject: Re: Ooops on read-only raid5 while unmounting as xfs
Date: Tue, 23 Jan 2007 12:31:49 +1100 [thread overview]
Message-ID: <17845.25989.10063.901037@notabene.brown> (raw)
In-Reply-To: message from Francois Barre on Thursday January 18
On Thursday January 18, francois.barre@gmail.com wrote:
> Hi all,
>
> I've hit the following bug while unmounting a xfs partition
>
> ----------- [cut here ] --------- [please bite here ] ---------
> Kernel BUG at drivers/md/md.c:5035
....
>
> Kernel : stock-kernel 2.6.18.6, x86_64
> Setup : xfs on raid5, on 5 250Go ieee1394 drives
> Way to reproduce :
> 1. assemble the array
> 2. mount the xfs array
> 3. mark the array read-only (mdadm -o)
You shouldn't be able to do this. It should only be possible to set
an array to read-only when it is not in use. The fact that you cannot
suggests something else if wrong.
Are you able to stop the array (mdadm -S) while the xfs filesystem is
still mounte?d?
> 4. umount the xfs array...
>
> I guess the problem is hit in md.c: md_write_start(), at the
> BUG_ON(mddev->ro == 1). It is obvious that my mddev->ro is set to 1,
> because I set it read-only.
> Nowhere before md_write_start() the check on mddev->ro == 1 is done,
> so that the upper layer never sees that the underlying device is
> read-only. As a result, when xfs wishes to write to it, bad things
> happen.
>
> May it be possible to relax the BUG_ON() and be able to send to
> upper-layer a more gentle message ?
Maybe... but I think I would rather make sure that you cannot set to
read-only while mounted.
If there some particular reason you were doing this?
Thanks,
NeilBrown
next prev parent reply other threads:[~2007-01-23 1:31 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-01-18 10:18 Ooops on read-only raid5 while unmounting as xfs Francois Barre
2007-01-23 1:31 ` Neil Brown [this message]
2007-01-23 14:42 ` Francois Barre
2007-01-23 23:54 ` Neil Brown
2007-01-24 22:23 ` Nix
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