linux-kernel - Re: [stable] [Stable-review] [116/165] ext4: dont return to userspace after freezing the fs with a mutex held

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Date:	Wed, 11 Aug 2010 08:20:55 -0400
From:	Eric Sandeen <sandeen@...hat.com>
To:	Stefan Bader <stefan.bader@...onical.com>
CC:	Greg KH <greg@...ah.com>,
	Henrique de Moraes Holschuh <hmh@....eng.br>,
	Greg KH <gregkh@...e.de>, linux-kernel@...r.kernel.org,
	stable@...nel.org, akpm@...ux-foundation.org,
	torvalds@...ux-foundation.org, stable-review@...nel.org,
	alan@...rguk.ukuu.org.uk
Subject: Re: [stable] [Stable-review] [116/165] ext4: dont return to userspace
 after freezing the fs with a mutex held

Stefan Bader wrote:
> On 08/10/2010 10:16 PM, Greg KH wrote:
>> On Mon, Aug 09, 2010 at 11:00:43AM +0200, Stefan Bader wrote:
>>> On 08/07/2010 03:38 PM, Eric Sandeen wrote:
>>>> Henrique de Moraes Holschuh wrote:
>>>>> On Mon, 02 Aug 2010, Greg KH wrote:
>>>>>> On Mon, Aug 02, 2010 at 12:02:45PM -0500, Eric Sandeen wrote:
>>>>>>> On 08/02/2010 07:04 AM, Stefan Bader wrote:
>>>>>>>> We have reports about this patch breaking lvm snapshhots. Eric, there is a patch
>>>>>>>> mentioned which is supposed to fix things but its not upstream, yet.
>>>>>>>> Do you know what happened to that?
>>>>>>> right, patch below is needed to fix things.
>>>>>>>
>>>>>>> Ted just acked it on the list recently; Greg, I'd either drop 116/165
>>>>>>> for now, or include the patch below which should be upstream soon...
>>>>>> I can't take anything that isn't upstream yet.
>>>>>>
>>>>>> And I just released with this patch in the kernel, should I do a revert
>>>>>> and do a new release?
>>>>> Any answers on this?
>>>>>
>>>> Yes, I'd revert it for now, I'm afraid, if the other patch isn't upstream
>>>> yet.
>>>>
>>>> Sorry about that,
>>>>
>>>> -Eric
>>> Upstream as of now (same SHA1 as in linux-next):
>>>
>>> >From 437f88cc031ffe7f37f3e705367f4fe1f4be8b0f Mon Sep 17 00:00:00 2001
>>> From: Eric Sandeen <sandeen@...deen.net>
>>> Date: Sun, 1 Aug 2010 17:33:29 -0400
>>> Subject: [PATCH] (pre-stable) ext4: fix freeze deadlock under IO
>> It looks like I can't drop the original one, as this patch builds on it.
>> So I'll just queue this one up.
>>
>> Should it also go into other -stable releases (like .35 and/or .34 -stable?)
>>
> 
> Final call would be Eric/Ted but as far as I can see:
> 
> .34: not for now (patch that causes regression not backported there (yet))
> .35: yes (offending patch has been in 2.6.35-rc1)

As long as the 2 patches go together it should be fine, I don't think there
are other significant dependencies.

It's also not really an urgent one to fix; returning to userspace w/ a lock
held is pretty icky but in practice has not been an actual problem AFAIK; most
people use lvm to freeze/unfreeze and it all gets cleaned up....

-Eric

> -Stefan
> 
>> thanks,
>>
>> greg k-h
> 

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