raid5: set bio bi_vcnt 0 for discard request
commit 37c61ff31e9b5e3fcf3cc6579f5c68f6ad40c4b1 upstream.
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+
Reported-by: Jes Sorensen <Jes.Sorensen@redhat.com>
Signed-off-by: Shaohua Li <shli@fusionio.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index a35b846..279dd99 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -668,6 +668,12 @@
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);
@@ -706,6 +712,12 @@
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),