linux-kernel - Re: [PATCH] quota: Turn quotas off when remounting read-only

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Message-ID: <47AB5B9F.8090302@msgid.tls.msk.ru>
Date:	Thu, 07 Feb 2008 22:27:27 +0300
From:	Michael Tokarev <mjt@....msk.ru>
To:	Andrew Morton <akpm@...ux-foundation.org>
CC:	Jan Kara <jack@...e.cz>, linux-kernel@...r.kernel.org,
	stable@...nel.org
Subject: Re: [PATCH] quota: Turn quotas off when remounting read-only

Andrew Morton wrote:
> On Thu, 7 Feb 2008 15:37:21 +0100 Jan Kara <jack@...e.cz> wrote:
> 
>> Turn off quotas before filesystem is remounted read only. Otherwise quota will
>> try to write to read-only filesystem which does no good... We could also just
>> refuse to remount ro when quota is enabled but turning quota off is consistent
>> with what we do on umount.

[a nice one-liner snipped]

> Cool.  And this is applicable to 2.6.23, 2.6.22 and even earlier, isn't it?

Provided the amount of time this issue exists, I don't think it's worth
to push it to -stable.  It's an oooooooold, issue, which happens quite
rarely, and no one bothered to report it so far...  But it's not my
call... ;)

But...  I'm thinking about this scenario:

 # mount /data
 # quotaon /data
 (some maintenance stuff to be planned)
 # mount -o remount,ro /data
 (do backup etc)
 # mount -r remount,rw /data

at this point, it's expected that quota on /data is enabled.
After this patch, it's not anymore...

I think it's more usual scenario than mine (umount instead of
remount-rw).  And this change will break it.  So I'm not sure
what really to do here.  Probably refusing remount-ro if quota
is on is better...  it's annoying for sure, but at least it's
explicit, and avoids the handg too.

/mjt
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