From 0cc67cd9c55c4b1f076abca06c922751088e6d86 Mon Sep 17 00:00:00 2001 From: Mike Snitzer Date: Tue, 20 Aug 2013 15:02:41 -0400 Subject: [PATCH] dm thin: fix stacking of geometry limits Do not blindly override the queue limits (specifically io_min and io_opt). Allow traditional stacking of these limits if io_opt is a factor of the thin-pool's data block size. Without this patch mkfs.xfs does not recognize the thin device's provided limits as a useful geometry (e.g. raid) so these hints are ignored. This was due to setting io_min to a useless value. Signed-off-by: Mike Snitzer Signed-off-by: Alasdair G Kergon Acked-by: Joe Thornber --- drivers/md/dm-thin.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c index 88f2f802d528..21328a371e58 100644 --- a/drivers/md/dm-thin.c +++ b/drivers/md/dm-thin.c @@ -2648,9 +2648,17 @@ static void pool_io_hints(struct dm_target *ti, struct queue_limits *limits) { struct pool_c *pt = ti->private; struct pool *pool = pt->pool; + uint64_t io_opt_sectors = limits->io_opt >> SECTOR_SHIFT; - blk_limits_io_min(limits, 0); - blk_limits_io_opt(limits, pool->sectors_per_block << SECTOR_SHIFT); + /* + * If the system-determined stacked limits are compatible with the + * pool's blocksize (io_opt is a factor) do not override them. + */ + 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_opt(limits, pool->sectors_per_block << SECTOR_SHIFT); + } /* * pt->adjusted_pf is a staging area for the actual features to use.