From 563d232b4c54c5c4433926ab299dfb729a283372 Mon Sep 17 00:00:00 2001
From: Lukas Czerner <lczerner@redhat.com>
Date: Wed, 11 Jun 2014 12:28:43 -0400
Subject: [PATCH] dm thin: update discard_granularity to reflect the thin-pool
blocksize
commit 09869de57ed2728ae3c619803932a86cb0e2c4f8 upstream.
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 <zkabelac@redhat.com>
Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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 7d0ac0a6e724..86a2a5e3b26b 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -2647,7 +2647,8 @@ 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;
}
--
2.34.1