[PATCH v2 5/5] md/raid10: Atomic write support

[John Garry]

Set BLK_FEAT_ATOMIC_WRITES_STACKED to enable atomic writes.

For an attempt to atomic write to a region which has bad blocks, error
the write as we just cannot do this. It is unlikely to find devices which
support atomic writes and bad blocks.

Signed-off-by: John Garry <john.g.garry@xxxxxxxxxx>
---
 drivers/md/raid10.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 9c56b27b754a..aacd8c3381f5 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -1454,6 +1454,13 @@ static void raid10_write_request(struct mddev *mddev, struct bio *bio,
 
 			is_bad = is_badblock(rdev, dev_sector, max_sectors,
 					     &first_bad, &bad_sectors);
+
+			if (is_bad && bio->bi_opf & REQ_ATOMIC) {
+				/* We just cannot atomically write this ... */
+				error = -EFAULT;
+				goto err_handle;
+			}
+
 			if (is_bad && first_bad <= dev_sector) {
 				/* Cannot write here at all */
 				bad_sectors -= (dev_sector - first_bad);
@@ -4029,6 +4036,7 @@ static int raid10_set_queue_limits(struct mddev *mddev)
 	lim.max_write_zeroes_sectors = 0;
 	lim.io_min = mddev->chunk_sectors << 9;
 	lim.io_opt = lim.io_min * raid10_nr_stripes(conf);
+	lim.features |= BLK_FEAT_ATOMIC_WRITES_STACKED;
 	err = mddev_stack_rdev_limits(mddev, &lim, MDDEV_STACK_INTEGRITY);
 	if (err) {
 		queue_limits_cancel_update(mddev->gendisk->queue);
-- 
2.31.1