From: Mikulas Patocka mpatocka@redhat.com
commit 97f433c3601a24d3513d06f575a389a2ca4e11e4 upstream.
We get 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.
Cc: stable@vger.kernel.org Reviewed-by: Ming Lei ming.lei@redhat.com Signed-off-by: Mikulas Patocka mpatocka@redhat.com Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- block/blk-settings.c | 12 ++++++++++++ 1 file changed, 12 insertions(+)
--- a/block/blk-settings.c +++ b/block/blk-settings.c @@ -473,6 +473,14 @@ void blk_queue_stack_limits(struct reque } EXPORT_SYMBOL(blk_queue_stack_limits);
+static unsigned int blk_round_down_sectors(unsigned int sectors, unsigned int lbs) +{ + sectors = round_down(sectors, lbs >> SECTOR_SHIFT); + if (sectors < PAGE_SIZE >> SECTOR_SHIFT) + sectors = PAGE_SIZE >> SECTOR_SHIFT; + return sectors; +} + /** * blk_stack_limits - adjust queue_limits for stacked devices * @t: the stacking driver limits (top device) @@ -586,6 +594,10 @@ int blk_stack_limits(struct queue_limits ret = -1; }
+ t->max_sectors = blk_round_down_sectors(t->max_sectors, t->logical_block_size); + t->max_hw_sectors = blk_round_down_sectors(t->max_hw_sectors, t->logical_block_size); + t->max_dev_sectors = blk_round_down_sectors(t->max_dev_sectors, t->logical_block_size); + /* Discard alignment and granularity */ if (b->discard_granularity) { alignment = queue_limit_discard_alignment(b, start);