From f610937214e2ac8c4225df9a124ea0de1f030626 Mon Sep 17 00:00:00 2001 From: Mike Snitzer Date: Tue, 20 Aug 2013 15:02:41 -0400 Subject: dm cache: 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 cache's data block size. Without this patch mkfs.xfs does not recognize the cache 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 diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c index 31985ea..22ff650 100644 --- a/drivers/md/dm-cache-target.c +++ b/drivers/md/dm-cache-target.c @@ -2612,9 +2612,17 @@ static void set_discard_limits(struct cache *cache, struct queue_limits *limits) static void cache_io_hints(struct dm_target *ti, struct queue_limits *limits) { struct cache *cache = ti->private; + uint64_t io_opt_sectors = limits->io_opt >> SECTOR_SHIFT; - blk_limits_io_min(limits, 0); - blk_limits_io_opt(limits, cache->sectors_per_block << SECTOR_SHIFT); + /* + * If the system-determined stacked limits are compatible with the + * cache's blocksize (io_opt is a factor) do not override them. + */ + if (io_opt_sectors < cache->sectors_per_block || + do_div(io_opt_sectors, cache->sectors_per_block)) { + blk_limits_io_min(limits, 0); + blk_limits_io_opt(limits, cache->sectors_per_block << SECTOR_SHIFT); + } set_discard_limits(cache, limits); } -- cgit v0.10.2