From 3c0049a01b2176413696177f837b3ef33860ec13 Mon Sep 17 00:00:00 2001 From: Guoqing Jiang Date: Mon, 4 Oct 2021 23:34:48 +0800 Subject: [PATCH] md/raid1: only allocate write behind bio for WriteMostly device commit fd3b6975e9c11c4fa00965f82a0bfbb3b7b44101 upstream. Commit 6607cd319b6b91bff94e90f798a61c031650b514 ("raid1: ensure write behind bio has less than BIO_MAX_VECS sectors") tried to guarantee the size of behind bio is not bigger than BIO_MAX_VECS sectors. Unfortunately the same calltrace still could happen since an array could enable write-behind without write mostly device. To match the manpage of mdadm (which says "write-behind is only attempted on drives marked as write-mostly"), we need to check WriteMostly flag to avoid such unexpected behavior. [1]. https://bugzilla.kernel.org/show_bug.cgi?id=213181#c25 Cc: stable@vger.kernel.org # v5.12+ Cc: Jens Stutte Reported-by: Jens Stutte Signed-off-by: Guoqing Jiang Signed-off-by: Song Liu Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- drivers/md/raid1.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c index 19598bd..6ba12f0 100644 --- a/drivers/md/raid1.c +++ b/drivers/md/raid1.c @@ -1496,7 +1496,7 @@ static void raid1_write_request(struct mddev *mddev, struct bio *bio, if (!r1_bio->bios[i]) continue; - if (first_clone) { + if (first_clone && test_bit(WriteMostly, &rdev->flags)) { /* do behind I/O ? * Not if there are too many, or cannot * allocate memory, or a reader on WriteMostly -- 2.7.4