| From | Kamal Mostafa <> | Subject | [PATCH 3.8 079/116] dm thin: update discard_granularity to reflect the thin-pool blocksize | Date | Tue, 22 Jul 2014 15:21:30 -0700 |
| |
3.8.13.27 -stable review patch. If anyone has any objections, please let me know.
------------------
From: Lukas Czerner <lczerner@redhat.com>
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: Kamal Mostafa <kamal@canonical.com> --- 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 ca954b1..3d183ca 100644 --- a/drivers/md/dm-thin.c +++ b/drivers/md/dm-thin.c @@ -2479,7 +2479,8 @@ 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 if (block_size_is_power_of_two(pool)) limits->discard_granularity = pool->sectors_per_block << SECTOR_SHIFT; else -- 1.9.1
|