From b7c18b17a173087ce97e809cefd55e581121f19e Mon Sep 17 00:00:00 2001 From: John Garry Date: Sun, 4 May 2025 11:26:45 +0200 Subject: [PATCH] dm-table: Set BLK_FEAT_ATOMIC_WRITES for target queue limits 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") Cc: stable@vger.kernel.org # v6.14 Signed-off-by: John Garry Signed-off-by: Mikulas Patocka --- drivers/md/dm-table.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c index a937e1e12482..9da5193e4ca9 100644 --- a/drivers/md/dm-table.c +++ b/drivers/md/dm-table.c @@ -430,6 +430,12 @@ 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); + mutex_lock(&q->limits_lock); if (blk_stack_limits(limits, &q->limits, get_start_sect(bdev) + start) < 0) -- 2.50.1