kernel/dm-thin-update-discard_gran...

44 lines
1.7 KiB
Diff

Bugzilla: 1106856
Upstream-status: 3.16 and CC'd to stable
From 4adc9ea8915ff9904c3279b1b36478482d1c0825 Mon Sep 17 00:00:00 2001
From: Lukas Czerner <lczerner@redhat.com>
Date: Wed, 11 Jun 2014 12:28:43 -0400
Subject: 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 <zkabelac@redhat.com>
Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index a0bdd56..fc9c848 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;
}
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