From: Mikulas Patocka The kernel currently assumes that limits->discard_granularity is a power of two so the thin target can set this limit only if it uses a power of two block size. Signed-off-by: Mikulas Patocka Signed-off-by: Alasdair G Kergon --- drivers/md/dm-thin.c | 3 ++- drivers/md/dm-thin.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) Index: linux/drivers/md/dm-thin.c =================================================================== --- linux.orig/drivers/md/dm-thin.c +++ linux/drivers/md/dm-thin.c @@ -2498,7 +2498,8 @@ static void set_discard_limits(struct po * This is just a hint, and not enforced. We have to cope with * bios that overlap 2 blocks. */ - limits->discard_granularity = pool->sectors_per_block << SECTOR_SHIFT; + if (!(pool->sectors_per_block & (pool->sectors_per_block - 1))) + limits->discard_granularity = pool->sectors_per_block << SECTOR_SHIFT; limits->discard_zeroes_data = pool->pf.zero_new_blocks; }