From 7fc8f632e68cd4db3bfee11ff7aa2ac731c5147a Mon Sep 17 00:00:00 2001 From: John Garry Date: Wed, 3 Sep 2025 16:10:52 +0000 Subject: [PATCH] md/md-linear: Enable atomic writes All the infrastructure has already been plumbed to support this for stacked devices, so just enable the request_queue limits features flag. A note about chunk sectors for linear arrays: While it is possible to set a chunk sectors param for building a linear array, this is for specifying the granularity at which data sectors from the device are used. It is not the same as a stripe size, like for RAID0. As such, it is not appropriate to set chunk_sectors request queue limit to the same value, as chunk_sectors request limit is a boundary for which requests cannot straddle. However, request_queue limit max_hw_sectors is set to chunk sectors, which almost has the same effect as setting chunk_sectors limit. Link: https://lore.kernel.org/linux-raid/20250903161052.3326176-1-john.g.garry@oracle.com Signed-off-by: John Garry Reviewed-by: Yu Kuai Signed-off-by: Yu Kuai --- drivers/md/md-linear.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/md/md-linear.c b/drivers/md/md-linear.c index 7033d982d3771..25a6ddedea658 100644 --- a/drivers/md/md-linear.c +++ b/drivers/md/md-linear.c @@ -75,6 +75,7 @@ static int linear_set_limits(struct mddev *mddev) lim.max_write_zeroes_sectors = mddev->chunk_sectors; lim.max_hw_wzeroes_unmap_sectors = mddev->chunk_sectors; lim.io_min = mddev->chunk_sectors << 9; + lim.features |= BLK_FEAT_ATOMIC_WRITES; err = mddev_stack_rdev_limits(mddev, &lim, MDDEV_STACK_INTEGRITY); if (err) return err; -- 2.47.3