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From: Bart Van Assche <Bart.VanAssche@wdc.com>
To: "shli@kernel.org" <shli@kernel.org>
Cc: "linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
	"jthumshirn@suse.de" <jthumshirn@suse.de>,
	"linux-raid@vger.kernel.org" <linux-raid@vger.kernel.org>,
	"hch@lst.de" <hch@lst.de>,
	"martin.petersen@oracle.com" <martin.petersen@oracle.com>,
	"axboe@kernel.dk" <axboe@kernel.dk>,
	"ming.lei@redhat.com" <ming.lei@redhat.com>,
	"linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
	"oleksandr@natalenko.name" <oleksandr@natalenko.name>,
	"hare@suse.com" <hare@suse.com>
Subject: Re: [PATCH v8 03/10] md: Neither resync nor reshape while the system is frozen
Date: Wed, 11 Oct 2017 17:17:56 +0000	[thread overview]
Message-ID: <1507742275.2477.20.camel@wdc.com> (raw)
In-Reply-To: <20171011014830.ps3v3yxny27wv7mc@kernel.org>

On Tue, 2017-10-10 at 18:48 -0700, Shaohua Li wrote:
> The problem is __md_stop_writes set some bit like MD_RECOVERY_FROZEN, which
> will prevent md_check_recovery restarting resync/reshape. I think we need
> preserve mddev->recovery in suspend prepare and restore after resume

Hello Shaohua,

As far as I can see __md_stop_writes() sets MD_RECOVERY_FROZEN and can set
MD_RECOVERY_INTR. Since md_check_recovery() clears MD_RECOVERY_INTR I think
it should be sufficient to save and restore the state of the
MD_RECOVERY_FROZEN flag. However, when I ran the following test:
* echo frozen > /sys/block/md0/md/sync_action
* cat /sys/block/md0/md/sync_action
* systemctl hibernate
* (power on system again)
* cat /sys/block/md0/md/sync_action

the output that appeared was as follows:

frozen
idle

Does that mean that a hibernate or suspend followed by a resume is sufficient
to clear the MD_RECOVERY_FROZEN flag for the md drivers and hence that the
patch at the start of this e-mail thread does not need any further
modifications?

Thanks,

Bart.

  reply	other threads:[~2017-10-11 17:17 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20171010210346.14574-1-bart.vanassche@wdc.com>
2017-10-10 21:03 ` [PATCH v8 01/10] md: Rename md_notifier into md_reboot_notifier Bart Van Assche
2017-10-10 21:03 ` [PATCH v8 02/10] md: Introduce md_stop_all_writes() Bart Van Assche
2017-10-10 21:03 ` [PATCH v8 03/10] md: Neither resync nor reshape while the system is frozen Bart Van Assche
2017-10-10 22:30   ` Shaohua Li
2017-10-10 23:33     ` Bart Van Assche
2017-10-11  1:48       ` Shaohua Li
2017-10-11 17:17         ` Bart Van Assche [this message]
2017-10-11 19:32           ` Shaohua Li
2017-10-12 16:59             ` Bart Van Assche
2017-10-12 17:45               ` Shaohua Li

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