@@ -4334,10 +4334,9 @@ static void thin_io_hints(struct dm_target *ti, struct queue_limits *limits)
{
struct thin_c *tc = ti->private;
struct pool *pool = tc->pool;
- struct queue_limits *pool_limits = dm_get_queue_limits(pool->pool_md);
- if (!pool_limits->discard_granularity)
- return; /* pool's discard support is disabled */
+ if (!pool->pf.discard_enabled)
+ return;
limits->discard_granularity = pool->sectors_per_block << SECTOR_SHIFT;
limits->max_discard_sectors = 2048 * 1024 * 16; /* 16G */
This is a note to let you know that I have just added a patch titled dm thin: fix regression in advertised discard limits to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree which can be found at: http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-4.2.y-queue This patch is scheduled to be released in version 4.2.8-ckt2. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 4.2.y-ckt tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ---8<------------------------------------------------------------ From ecef95fe0ba4ae7b76d612990fd2acce57a0e28f Mon Sep 17 00:00:00 2001 From: Mike Snitzer <snitzer@redhat.com> Date: Mon, 23 Nov 2015 13:44:38 -0500 Subject: dm thin: fix regression in advertised discard limits commit 0fcb04d59351f790efb8da18edefd6ab4d9bbf3b upstream. When establishing a thin device's discard limits we cannot rely on the underlying thin-pool device's discard capabilities (which are inherited from the thin-pool's underlying data device) given that DM thin devices must provide discard support even when the thin-pool's underlying data device doesn't support discards. Users were exposed to this thin device discard limits regression if their thin-pool's underlying data device does _not_ support discards. This regression caused all upper-layers that called the blkdev_issue_discard() interface to not be able to issue discards to thin devices (because discard_granularity was 0). This regression wasn't caught earlier because the device-mapper-test-suite's extensive 'thin-provisioning' discard tests are only ever performed against thin-pool's with data devices that support discards. Fix is to have thin_io_hints() test the pool's 'discard_enabled' feature rather than inferring whether or not a thin device's discard support should be enabled by looking at the thin-pool's discard_granularity. Fixes: 216076705 ("dm thin: disable discard support for thin devices if pool's is disabled") Reported-by: Mike Gerber <mike@sprachgewalt.de> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- drivers/md/dm-thin.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) -- 1.9.1