From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Disseldorp Subject: [PATCH v2] rbd: set discard alignment to zero Date: Thu, 2 Nov 2017 01:05:11 +0100 Message-ID: <20171102000511.29106-1-ddiss@suse.de> References: <20171102004338.39d87dea@suse.de> Return-path: Received: from mx2.suse.de ([195.135.220.15]:42171 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752258AbdKBAF2 (ORCPT ); Wed, 1 Nov 2017 20:05:28 -0400 In-Reply-To: <20171102004338.39d87dea@suse.de> Sender: ceph-devel-owner@vger.kernel.org List-ID: To: ceph-devel@vger.kernel.org Cc: Mike Christie , Ilya Dryomov , David Disseldorp RBD devices are currently incorrectly initialised with the block queue discard_alignment set to the underlying RADOS object size. As per Documentation/ABI/testing/sysfs-block: The discard_alignment parameter indicates how many bytes the beginning of the device is offset from the internal allocation unit's natural alignment. Correcting the discard_alignment parameter from the RADOS object size to zero (the blk_set_default_limits() default) has no effect on how discard requests are propagated through the block layer - @alignment in __blkdev_issue_discard() remains zero. However, it does fix the UNMAP granularity alignment value advertised to SCSI initiators via the Block Limits VPD. Signed-off-by: David Disseldorp --- drivers/block/rbd.c | 1 - 1 file changed, 1 deletion(-) diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c index b640ad8a6d20..016542c75e1f 100644 --- a/drivers/block/rbd.c +++ b/drivers/block/rbd.c @@ -4423,7 +4423,6 @@ static int rbd_init_disk(struct rbd_device *rbd_dev) /* enable the discard support */ queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q); q->limits.discard_granularity = segment_size; - q->limits.discard_alignment = segment_size; blk_queue_max_discard_sectors(q, segment_size / SECTOR_SIZE); blk_queue_max_write_zeroes_sectors(q, segment_size / SECTOR_SIZE); -- 2.13.6