Jes Sorensen <Jes.Sorensen@xxxxxxxxxx> writes: > Neil Brown <neilb@xxxxxxx> writes: >> Jes Sorensen <Jes.Sorensen@xxxxxxxxxx> writes: >> >>> Hi Neil, >>> >>> I think we have some bad side effects with this patch: >>> >>> commit 199dc6ed5179251fa6158a461499c24bdd99c836 >>> Author: NeilBrown <neilb@xxxxxxxx> >>> Date: Mon Aug 3 13:11:47 2015 +1000 >>> >>> md/raid0: update queue parameter in a safer location. >>> >>> When a (e.g.) RAID5 array is reshaped to RAID0, the updating >>> of queue parameters (e.g. max number of sectors per bio) is >>> done in the wrong place. >>> It should be part of ->run, but it is actually part of ->takeover. >>> This means it happens before level_store() calls: >>> >>> blk_set_stacking_limits(&mddev->queue->limits); >>> >>> Running the '03r0assem' test suite fills my kernel log with output like >>> below. Yi Zhang also had issues where writes failed too. >>> >>> robably something we need to resolve for 4.2-final or revert the >>> offending patch. >>> >>> Cheers, >>> Jes >>> >>> md: bind<loop0> >>> md: bind<loop1> >>> md: bind<loop2> >>> md/raid0:md2: md_size is 116736 sectors. >>> md: RAID0 configuration for md2 - 1 zone >>> md: zone0=[loop0/loop1/loop2] >>> zone-offset= 0KB, device-offset= 0KB, size= 58368KB >>> >>> md2: detected capacity change from 0 to 59768832 >>> bio too big device loop0 (296 > 255) >>> bio too big device loop0 (272 > 255) >> >> 1/ Why do you blame that particular patch? >> >> 2/ Where is that error message coming from? I cannot find "bio too big" >> in the kernel (except in a comment). >> Commit: 54efd50bfd87 ("block: make generic_make_request handle >> arbitrarily sized bios") >> removed the only instance of the error message that I know of. >> >> Which kernel exactly are you testing? > > I blame it because of bisect - I revert that patch and the issue goes > away. > > I checked out 199dc6ed5179251fa6158a461499c24bdd99c836 in Linus' tree, > see the bio too large. I revert it and it goes away. Well that's pretty convincing - thanks. And as you say - it is tagged for -stable so really needs to be fixed. Stares at the code again. And again. Ahhh. that patch moved the blk_queue_max_hw_sectors(mddev->queue, mddev->chunk_sectors); to after disk_stack_limits(...); That is wrong. Could you confirm that this fixes your test? Thanks, NeilBrown diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c index 4a13c3cb940b..0875e5e7e09a 100644 --- a/drivers/md/raid0.c +++ b/drivers/md/raid0.c @@ -431,12 +431,6 @@ static int raid0_run(struct mddev *mddev) struct md_rdev *rdev; bool discard_supported = false; - rdev_for_each(rdev, mddev) { - disk_stack_limits(mddev->gendisk, rdev->bdev, - rdev->data_offset << 9); - if (blk_queue_discard(bdev_get_queue(rdev->bdev))) - discard_supported = true; - } blk_queue_max_hw_sectors(mddev->queue, mddev->chunk_sectors); blk_queue_max_write_same_sectors(mddev->queue, mddev->chunk_sectors); blk_queue_max_discard_sectors(mddev->queue, mddev->chunk_sectors); @@ -445,6 +439,12 @@ static int raid0_run(struct mddev *mddev) blk_queue_io_opt(mddev->queue, (mddev->chunk_sectors << 9) * mddev->raid_disks); + rdev_for_each(rdev, mddev) { + disk_stack_limits(mddev->gendisk, rdev->bdev, + rdev->data_offset << 9); + if (blk_queue_discard(bdev_get_queue(rdev->bdev))) + discard_supported = true; + } if (!discard_supported) queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, mddev->queue); else
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