dm-mirror: Support atomic writes

Support atomic writes by setting DM_TARGET_ATOMIC_WRITES for the target
type, and also unmasking REQ_ATOMIC from the submitted bio op flags.

Signed-off-by: John Garry <[email protected]>
Reviewed-by: Mike Snitzer <[email protected]>
Signed-off-by: Mikulas Patocka <[email protected]>

Author: johnpgarry

drivers/md/dm-raid1.c

@@ -656,7 +656,7 @@ static void do_write(struct mirror_set *ms, struct bio *bio)
 	unsigned int i;
 	struct dm_io_region io[MAX_NR_MIRRORS], *dest = io;
 	struct mirror *m;
-	blk_opf_t op_flags = bio->bi_opf & (REQ_FUA | REQ_PREFLUSH);
+	blk_opf_t op_flags = bio->bi_opf & (REQ_FUA | REQ_PREFLUSH | REQ_ATOMIC);
 	struct dm_io_request io_req = {
 		.bi_opf = REQ_OP_WRITE | op_flags,
 		.mem.type = DM_IO_BIO,
@@ -1483,8 +1483,9 @@ static int mirror_iterate_devices(struct dm_target *ti,
 
 static struct target_type mirror_target = {
 	.name	 = "mirror",
-	.version = {1, 14, 0},
+	.version = {1, 15, 0},
 	.module	 = THIS_MODULE,
+	.features = DM_TARGET_ATOMIC_WRITES,
 	.ctr	 = mirror_ctr,
 	.dtr	 = mirror_dtr,
 	.map	 = mirror_map,