Feature flag BLK_FEAT_ATOMIC_WRITES is not being properly set for the
target queue limits, and this means that atomic writes are not being
enabled for any dm personalities.
When calling dm_set_device_limits() -> blk_stack_limits() ->
... -> blk_stack_atomic_writes_limits(), the bottom device limits
(which corresponds to intermediate target queue limits) does not have
BLK_FEAT_ATOMIC_WRITES set, and so atomic writes can never be enabled.
Typically such a flag would be inherited from the stacked device in
dm_set_device_limits() -> blk_stack_limits() via BLK_FEAT_INHERIT_MASK,
but BLK_FEAT_ATOMIC_WRITES is not inherited as it's preferred to manually
enable on a per-personality basis.
Set BLK_FEAT_ATOMIC_WRITES manually for the intermediate target queue
limits from the stacked device to get atomic writes working.
Fixes: 3194e36488e2 ("dm-table: atomic writes support")
Signed-off-by: John Garry <john.g.garry@xxxxxxxxxx>
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 9e175c5e0634..b35e48fed641 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -431,6 +431,12 @@ static int dm_set_device_limits(struct dm_target *ti, struct dm_dev *dev,
return 0;
}
+ /*
+ * BLK_FEAT_ATOMIC_WRITES is not inherited from the bottom device in
+ * blk_stack_limits(), so do it manually.
+ */
+ limits->features |= (q->limits.features & BLK_FEAT_ATOMIC_WRITES);
+
if (blk_stack_limits(limits, &q->limits,
get_start_sect(bdev) + start) < 0)
DMWARN("%s: adding target device %pg caused an alignment inconsistency: "
--
2.31.1
