raid5: set bio bi_vcnt 0 for discard request

SCSI layer will add new payload for discard request. If two bios are merged to one, the second bio has bi_vcnt 1 which is set in raid5. This will confuse SCSI and cause oops. Suitable for backport to 3.7+ Cc: [email protected] (v3.7+) Reported-by: Jes Sorensen <[email protected]> Signed-off-by: Shaohua Li <[email protected]> Signed-off-by: NeilBrown <[email protected]> Acked-by: Martin K. Petersen <[email protected]>
kishon · Oct 24, 2013 · 37c61ff · 37c61ff
1 parent 905b029
commit 37c61ff
Showing 1 changed file with 12 additions and 0 deletions.
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
@@ -778,6 +778,12 @@ static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s)
 			bi->bi_io_vec[0].bv_len = STRIPE_SIZE;
 			bi->bi_io_vec[0].bv_offset = 0;
 			bi->bi_size = STRIPE_SIZE;
+			/*
+			 * If this is discard request, set bi_vcnt 0. We don't
+			 * want to confuse SCSI because SCSI will replace payload
+			 */
+			if (rw & REQ_DISCARD)
+				bi->bi_vcnt = 0;
 			if (rrdev)
 				set_bit(R5_DOUBLE_LOCKED, &sh->dev[i].flags);
 
@@ -816,6 +822,12 @@ static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s)
 			rbi->bi_io_vec[0].bv_len = STRIPE_SIZE;
 			rbi->bi_io_vec[0].bv_offset = 0;
 			rbi->bi_size = STRIPE_SIZE;
+			/*
+			 * If this is discard request, set bi_vcnt 0. We don't
+			 * want to confuse SCSI because SCSI will replace payload
+			 */
+			if (rw & REQ_DISCARD)
+				rbi->bi_vcnt = 0;
 			if (conf->mddev->gendisk)
 				trace_block_bio_remap(bdev_get_queue(rbi->bi_bdev),
 						      rbi, disk_devt(conf->mddev->gendisk),