From 09869de57ed2728ae3c619803932a86cb0e2c4f8 Mon Sep 17 00:00:00 2001 From: Lukas Czerner Date: Wed, 11 Jun 2014 12:28:43 -0400 Subject: [PATCH] dm thin: update discard_granularity to reflect the thin-pool blocksize DM thinp already checks whether the discard_granularity of the data device is a factor of the thin-pool block size. But when using the dm-thin-pool's discard passdown support, DM thinp was not selecting the max of the underlying data device's discard_granularity and the thin-pool's block size. Update set_discard_limits() to set discard_granularity to the max of these values. This enables blkdev_issue_discard() to properly align the discards that are sent to the DM thin device on a full block boundary. As such each discard will now cover an entire DM thin-pool block and the block will be reclaimed. Reported-by: Zdenek Kabelac Signed-off-by: Lukas Czerner Signed-off-by: Mike Snitzer Cc: stable@vger.kernel.org --- drivers/md/dm-thin.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c index a0bdd562e026..fc9c848a60c9 100644 --- a/drivers/md/dm-thin.c +++ b/drivers/md/dm-thin.c @@ -3094,7 +3094,8 @@ static void set_discard_limits(struct pool_c *pt, struct queue_limits *limits) */ if (pt->adjusted_pf.discard_passdown) { data_limits = &bdev_get_queue(pt->data_dev->bdev)->limits; - limits->discard_granularity = data_limits->discard_granularity; + limits->discard_granularity = max(data_limits->discard_granularity, + pool->sectors_per_block << SECTOR_SHIFT); } else limits->discard_granularity = pool->sectors_per_block << SECTOR_SHIFT; }