Commit fdfb4c8c authored Jul 18, 2014 by Mike Snitzer

dm thin: set minimum_io_size to pool's data block size

Before, if the block layer's limit stacking didn't establish an
optimal_io_size that was compatible with the thin-pool's data block size
we'd set optimal_io_size to the data block size and minimum_io_size to 0
(which the block layer adjusts to be physical_block_size).

Update pool_io_hints() to set both minimum_io_size and optimal_io_size
to the thin-pool's data block size.  This fixes an issue reported where
mkfs.xfs would create more XFS Allocation Groups on thinp volumes than
on a normal linear LV of comparable size, see:
https://bugzilla.redhat.com/show_bug.cgi?id=1003227



Reported-by: Chris Murphy <lists@colorremedies.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

parent 298a9fa0

drivers/md/dm-thin.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -3177,7 +3177,7 @@ static void pool_io_hints(struct dm_target ti, struct queue_limits limits)
		*/
		if (io_opt_sectors < pool->sectors_per_block \|\|
		do_div(io_opt_sectors, pool->sectors_per_block)) {
		blk_limits_io_min(limits, 0);
		blk_limits_io_min(limits, pool->sectors_per_block << SECTOR_SHIFT);
		blk_limits_io_opt(limits, pool->sectors_per_block << SECTOR_SHIFT);
		}

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