On Mon, Feb 22, 2021 at 01:15:32PM -0500, Mikulas Patocka wrote: > > > ---------- Forwarded message ---------- > Date: Thu, 19 Nov 2020 15:36:51 -0500 (EST) > From: Mikulas Patocka <mpatocka@xxxxxxxxxx> > To: David Teigland <teigland@xxxxxxxxxx>, Jens Axboe <axboe@xxxxxxxxx> > Cc: heinzm@xxxxxxxxxx, Zdenek Kabelac <zkabelac@xxxxxxxxxx>, > Marian Csontos <mcsontos@xxxxxxxxxx>, linux-block@xxxxxxxxxxxxxxx, > dm-devel@xxxxxxxxxx > Subject: [PATCH] blk-settings: make sure that max_sectors is aligned on > "logical_block_size" boundary. > > We get these I/O errors when we run md-raid1 on the top of dm-integrity on > the top of ramdisk: > device-mapper: integrity: Bio not aligned on 8 sectors: 0xff00, 0xff > device-mapper: integrity: Bio not aligned on 8 sectors: 0xff00, 0xff > device-mapper: integrity: Bio not aligned on 8 sectors: 0xffff, 0x1 > device-mapper: integrity: Bio not aligned on 8 sectors: 0xffff, 0x1 > device-mapper: integrity: Bio not aligned on 8 sectors: 0x8048, 0xff > device-mapper: integrity: Bio not aligned on 8 sectors: 0x8147, 0xff > device-mapper: integrity: Bio not aligned on 8 sectors: 0x8246, 0xff > device-mapper: integrity: Bio not aligned on 8 sectors: 0x8345, 0xbb > > The ramdisk device has logical_block_size 512 and max_sectors 255. The > dm-integrity device uses logical_block_size 4096 and it doesn't affect the > "max_sectors" value - thus, it inherits 255 from the ramdisk. So, we have > a device with max_sectors not aligned on logical_block_size. > > The md-raid device sees that the underlying leg has max_sectors 255 and it > will split the bios on 255-sector boundary, making the bios unaligned on > logical_block_size. > > In order to fix the bug, we round down max_sectors to logical_block_size. > > Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx> > Cc: stable@xxxxxxxxxxxxxxx > > --- > block/blk-settings.c | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > Index: linux-2.6/block/blk-settings.c > =================================================================== > --- linux-2.6.orig/block/blk-settings.c 2020-10-29 12:20:46.000000000 +0100 > +++ linux-2.6/block/blk-settings.c 2020-11-19 21:20:18.000000000 +0100 > @@ -591,6 +591,16 @@ int blk_stack_limits(struct queue_limits > ret = -1; > } > > + t->max_sectors = round_down(t->max_sectors, t->logical_block_size / 512); > + if (t->max_sectors < PAGE_SIZE / 512) > + t->max_sectors = PAGE_SIZE / 512; > + t->max_hw_sectors = round_down(t->max_hw_sectors, t->logical_block_size / 512); > + if (t->max_sectors < PAGE_SIZE / 512) if (t->max_hw_sectors < PAGE_SIZE / 512) > + t->max_hw_sectors = PAGE_SIZE / 512; > + t->max_dev_sectors = round_down(t->max_dev_sectors, t->logical_block_size / 512); > + if (t->max_sectors < PAGE_SIZE / 512) if (t->max_dev_sectors < PAGE_SIZE / 512) > + t->max_dev_sectors = PAGE_SIZE / 512; I'd suggest to add a helper(such as, blk_round_down_sectors()) to round_down each one. -- Ming
