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| author | Mike Snitzer <snitzer@redhat.com> | 2015-11-23 19:44:38 +0100 |
|---|---|---|
| committer | Mike Snitzer <snitzer@redhat.com> | 2015-11-23 20:54:46 +0100 |
| commit | 0fcb04d59351f790efb8da18edefd6ab4d9bbf3b (patch) | |
| tree | 49262cdba058160c53fe4a88e385f3ad037f883f /drivers | |
| parent | dm crypt: fix a possible hang due to race condition on exit (diff) | |
| download | linux-0fcb04d59351f790efb8da18edefd6ab4d9bbf3b.tar.xz linux-0fcb04d59351f790efb8da18edefd6ab4d9bbf3b.zip | |
dm thin: fix regression in advertised discard limits
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>
Cc: stable@vger.kernel.org # 4.1+
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/md/dm-thin.c | 5 |
1 files changed, 2 insertions, 3 deletions
diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c index 9f0b94fad361..63903a5a5d9e 100644 --- a/drivers/md/dm-thin.c +++ b/drivers/md/dm-thin.c @@ -4250,10 +4250,9 @@ 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 */ |