Commit 108d5817 authored Feb 23, 2021 by Mikulas Patocka Committed by Greg Kroah-Hartman Mar 04, 2021

blk-settings: align max_sectors on "logical_block_size" boundary



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>

parent 60ab88a4

block/blk-settings.c

+12 −0

Original line number	Diff line number	Diff line
		@@ -513,6 +513,14 @@ void blk_queue_io_opt(struct request_queue *q, unsigned int opt)
		}
		EXPORT_SYMBOL(blk_queue_io_opt);

		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_queue_stack_limits - inherit underlying queue limits for stacked drivers
		* @t: the stacking driver (top)
		@@ -639,6 +647,10 @@ int blk_stack_limits(struct queue_limits t, struct queue_limits b,
		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);