Messages in this thread Patch in this message | | | From | Jiri Slaby <> | Subject | [PATCH 3.12 092/170] dm thin: update discard_granularity to reflect the thin-pool blocksize | Date | Fri, 18 Jul 2014 14:11:37 +0200 |
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From: Lukas Czerner <lczerner@redhat.com>
3.12-stable review patch. If anyone has any objections, please let me know.
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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: Jiri Slaby <jslaby@suse.cz> --- 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 e4cc196634c1..f8c36d30eca8 100644 --- a/drivers/md/dm-thin.c +++ b/drivers/md/dm-thin.c @@ -2695,7 +2695,8 @@ 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; } -- 2.0.0
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