[PATCH] md/raid1,raid10: don't pass down the REQ_RAHEAD flag

[Mikulas Patocka <mpatocka@redhat.com>]

The commit e879a0d9cb08 ("md/raid1,raid10: don't ignore IO flags") breaks
the lvm2 test shell/lvcreate-large-raid.sh. The commit changes raid1 and
raid10 to pass down all the flags from the incoming bio. The problem is
when we pass down the REQ_RAHEAD flag - bios with this flag may fail
anytime and md-raid is not prepared to handle this failure.

This commit fixes the code, so that the REQ_RAHEAD flag is not passed
down.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Fixes: e879a0d9cb08 ("md/raid1,raid10: don't ignore IO flags")

---
 drivers/md/raid1.c  |    1 +
 drivers/md/raid10.c |    1 +
 2 files changed, 2 insertions(+)

Index: linux-2.6/drivers/md/raid1.c
===================================================================
--- linux-2.6.orig/drivers/md/raid1.c
+++ linux-2.6/drivers/md/raid1.c
@@ -1404,6 +1404,7 @@ static void raid1_read_request(struct md
 	read_bio->bi_iter.bi_sector = r1_bio->sector +
 		mirror->rdev->data_offset;
 	read_bio->bi_end_io = raid1_end_read_request;
+	read_bio->bi_opf &= ~REQ_RAHEAD;
 	if (test_bit(FailFast, &mirror->rdev->flags) &&
 	    test_bit(R1BIO_FailFast, &r1_bio->state))
 	        read_bio->bi_opf |= MD_FAILFAST;
Index: linux-2.6/drivers/md/raid10.c
===================================================================
--- linux-2.6.orig/drivers/md/raid10.c
+++ linux-2.6/drivers/md/raid10.c
@@ -1263,6 +1263,7 @@ static void raid10_write_one_disk(struct
 	mbio->bi_iter.bi_sector	= (r10_bio->devs[n_copy].addr +
 				   choose_data_offset(r10_bio, rdev));
 	mbio->bi_end_io	= raid10_end_write_request;
+	mbio->bi_opf &= ~REQ_RAHEAD;
 	if (!replacement && test_bit(FailFast,
 				     &conf->mirrors[devnum].rdev->flags)
 			 && enough(conf, devnum))