Re: [PATCH v2] Fix AFFS race condition.

From: Vladimir 'Ï-coder/phcoder' Serbinenko
Date: Mon May 14 2012 - 06:54:31 EST

On 14.05.2012 12:40, Marco Stornelli wrote:

> 2012/5/14 Jan Kara <jack@xxxxxxx>:
>> On Sun 13-05-12 15:44:33, Vladimir 'Ï-coder/phcoder' Serbinenko wrote:
>>> AFFS code preallocates several blocks as an optimisation. Unfortunately
>>> it's not protected by lock so the same blocks may end up allocated twice.
>>> Here is a fix.
>>> Signed-off-by: Vladimir Serbinenko <phcoder@xxxxxxxxx>
>> The patch looks good to me now. Thanks! You can add:
>> Reviewed-by: Jan Kara <jack@xxxxxxx>
>> Al, will you merge this patch through your tree? AFFS does not seem to
>> have a maintainer so you are a default fallback...
>> Honza
> I don't know the AFFS code, so only a question. Instead to use a spin
> lock, I think we can use a simple mutex. Or is the spin lock
> mandatory?

My first version used mutex. But then Jan suggested that since the
critical section is very short and doesn't contain any instructions
which might sleep, it's better for performance to use a spin lock.

Vladimir 'Ï-coder/phcoder' Serbinenko

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