From: "Martin K. Petersen" <martin.petersen@oracle.com>
To: Mike Snitzer <snitzer@redhat.com>
Cc: axboe@kernel.dk, linux-kernel@vger.kernel.org,
martin.petersen@oracle.com, dm-devel@redhat.com
Subject: Re: [PATCH v2] block: fix alignment_offset math that assumes io_min is a power-of-2
Date: Wed, 08 Oct 2014 20:23:10 -0400 [thread overview]
Message-ID: <yq1iojudrbl.fsf@sermon.lab.mkp.net> (raw)
In-Reply-To: <1412807173-15541-1-git-send-email-snitzer@redhat.com> (Mike Snitzer's message of "Wed, 8 Oct 2014 18:26:13 -0400")
>>>>> "Mike" == Mike Snitzer <snitzer@redhat.com> writes:
Mike> The math in both blk_stack_limits() and
Mike> queue_limit_alignment_offset() assume that a block device's io_min
Mike> (aka minimum_io_size) is always a power-of-2. Fix the math such
Mike> that it works for non-power-of-2 io_min.
Mike> This issue (of alignment_offset != 0) became apparent when testing
Mike> dm-thinp with a thinp blocksize that matches a RAID6 stripesize of
Mike> 1280K. Commit fdfb4c8c1 ("dm thin: set minimum_io_size to pool's
Mike> data block size") unlocked the potential for alignment_offset != 0
Mike> due to the dm-thin-pool's io_min possibly being a non-power-of-2.
Looks good to me, Mike.
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
--
Martin K. Petersen Oracle Linux Engineering
prev parent reply other threads:[~2014-10-09 0:23 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <to=1412805952-15316-1-git-send-email-snitzer@redhat.com>
2014-10-08 22:26 ` Mike Snitzer
2014-10-09 0:23 ` Martin K. Petersen [this message]
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