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From: Shaohua Li <shli@kernel.org>
To: Dan Williams <dan.j.williams@intel.com>
Cc: linux-raid@vger.kernel.org, neilb@suse.de, axboe@kernel.dk,
	Shaohua Li <shli@fusionio.com>
Subject: Re: [RFC 1/2] MD: raid5 trim support
Date: Tue, 17 Apr 2012 23:07:10 +0800	[thread overview]
Message-ID: <4F8D871E.2050403@kernel.org> (raw)
In-Reply-To: <CABE8wwswKWQ=LDbx0ysTaZf2Hz0jD_q45FNF0jw96ZwZdJiHPw@mail.gmail.com>

Hi Dan,
On 4/17/12 10:46 PM, Dan Williams wrote:
> On Tue, Apr 17, 2012 at 1:35 AM, Shaohua Li<shli@kernel.org>  wrote:
>> Discard for raid4/5/6 has limitation. If discard request size is small, we do
>> discard for one disk, but we need calculate parity and write parity disk.  To
>> correctly calculate parity, zero_after_discard must be guaranteed.
>
> I'm wondering if we could use the new bad blocks facility to mark
> discarded ranges so we don't necessarily need determinate data after
> discard.

It would be great the limitation can be avoided and the code can be
simplified. I didn't follow linux-raid maillist, can you point me the url
of the new bad blocks facility please?

Thanks,
Shaohua

  reply	other threads:[~2012-04-17 15:07 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-04-17  8:35 [RFC 0/2] raid5 trim support Shaohua Li
2012-04-17  8:35 ` [RFC 1/2] MD: " Shaohua Li
2012-04-17 14:46   ` Dan Williams
2012-04-17 15:07     ` Shaohua Li [this message]
2012-04-17 18:16       ` Dan Williams
2012-04-17 20:26     ` NeilBrown
2012-04-18  0:58       ` Shaohua Li
2012-04-18  4:48         ` NeilBrown
2012-04-18  5:30           ` Shaohua Li
2012-04-18  5:57             ` NeilBrown
2012-04-18  6:34               ` Shaohua Li
2012-04-25  3:43                 ` Shaohua Li
2012-05-08 10:16                   ` Shaohua Li
2012-05-08 15:52                     ` Dan Williams
2012-05-09  3:12                       ` Shaohua Li
2012-05-08 20:17                     ` NeilBrown
2012-04-17  8:35 ` [RFC 2/2] MD: raid5 avoid unnecessary zero page for trim Shaohua Li

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