From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Zdenek Kabelac , Lukas Czerner , Mike Snitzer Subject: [PATCH 3.15 064/122] dm thin: update discard_granularity to reflect the thin-pool blocksize Date: Mon, 7 Jul 2014 16:57:06 -0700 Message-Id: <20140707235736.192095368@linuxfoundation.org> In-Reply-To: <20140707235734.234226883@linuxfoundation.org> References: <20140707235734.234226883@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Lukas Czerner 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 Signed-off-by: Lukas Czerner Signed-off-by: Mike Snitzer Signed-off-by: Greg Kroah-Hartman --- drivers/md/dm-thin.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/drivers/md/dm-thin.c +++ b/drivers/md/dm-thin.c @@ -3068,7 +3068,8 @@ static void set_discard_limits(struct po */ 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; }