From: Christoph Hellwig <hch@lst.de>
To: jiangyiwen <jiangyiwen@huawei.com>
Cc: wangyibin@huawei.com, dm-devel@redhat.com, hch@lst.de,
Mike Snitzer <snitzer@redhat.com>
Subject: Re: dm-mpath: Handling SCSI-3 PR RELEASE in multi-controller environment
Date: Mon, 26 Sep 2016 18:03:17 +0200 [thread overview]
Message-ID: <20160926160317.GA17796@lst.de> (raw)
In-Reply-To: <57E392FA.3080006@huawei.com>
On Thu, Sep 22, 2016 at 04:14:50PM +0800, jiangyiwen wrote:
> I briefly reviewed the PR API. If I understand correctly, a bunch of PR
> dedicated operations (pr_ops) are defined in block_device_operations, which
> includes register, reserve, release, preempt and clear operations. But among
> these operations, only register() calls dm_call_pr(), which in turns iterates
> over the device for each path and does the registeration.
Register and unregister in fact, but they both multiple throught the
same method.
> My point is, we also need to do this in release operation, so that we can
> eliminate the possibility of trying to release the reservation on the wrong
> controller and get a fake success.
dm_grab_bdev_for_ioctl ensures that we have a working path. At least
that's the theory and my testing confirms it. If you know a case where
the release doesn't work using this path we'll need to fix.
next prev parent reply other threads:[~2016-09-26 16:03 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-21 9:14 dm-mpath: Handling SCSI-3 PR RELEASE in multi-controller environment jiangyiwen
2016-09-21 15:04 ` Mike Snitzer
2016-09-21 17:14 ` Christoph Hellwig
2016-09-22 8:14 ` jiangyiwen
2016-09-26 16:03 ` Christoph Hellwig [this message]
-- strict thread matches above, loose matches on Subject: below --
2016-10-09 13:12 wangyibin
2016-10-09 15:16 ` Christoph Hellwig
2016-10-13 9:19 ` Yibin Wang
2016-10-13 11:16 ` Yibin Wang
2016-10-14 13:48 ` Christoph Hellwig
2016-10-14 14:51 ` Christoph Hellwig
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