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From: NeilBrown <neilb@suse.de>
To: Shaohua Li <shli@fb.com>, linux-raid@vger.kernel.org
Cc: Kernel-team@fb.com, songliubraving@fb.com
Subject: Re: [PATCH 1/4] raid5-cache: use rcu api to access r5conf->log
Date: Wed, 06 Jan 2016 12:04:11 +1100	[thread overview]
Message-ID: <87fuyby0vo.fsf@notabene.neil.brown.name> (raw)
In-Reply-To: <b2e460b69224288a2b7dfc66f86672551cdb9319.1452028077.git.shli@fb.com>

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On Wed, Jan 06 2016, Shaohua Li wrote:

> If we add journal disk to an array which isn't created with journal, IO
> might be running in the array. We must be careful about the log checks
> to make sure log is fully initialized, which is the job of
> rcu_dereference(). Don't need rcu read lock protection here, as
> hotremove only happens when there is no write requests.

Very sensible, especially as conf->log is set using rcu_assign_ptr().

Applied, thanks
NeilBrown

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  reply	other threads:[~2016-01-06  1:04 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-01-05 21:26 [PATCH 0/4]raid5-cache: fix journal hotadd Shaohua Li
2016-01-05 21:26 ` [PATCH 1/4] raid5-cache: use rcu api to access r5conf->log Shaohua Li
2016-01-06  1:04   ` NeilBrown [this message]
2016-01-05 21:26 ` [PATCH 2/4] raid5-cache: avoid write failure for journal hotadd Shaohua Li
2016-01-06  1:03   ` NeilBrown
2016-01-05 21:26 ` [PATCH 3/4] raid5-cache: handle flush request " Shaohua Li
2016-01-06  1:12   ` NeilBrown
2016-01-06  1:47     ` Shaohua Li
2016-01-06  2:07       ` NeilBrown
2016-01-05 21:26 ` [PATCH 4/4] raid5-cache: handle batch stripe " Shaohua Li

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