From: Shaohua Li <shli@xxxxxx> After bio is submitted, we should not clone it as its bi_iter might be invalid by driver. This is the case of behind_master_bio. In certain situration, we could dispatch behind_master_bio immediately for the first disk and then clone it for other disks. https://bugzilla.kernel.org/show_bug.cgi?id=196383 Reported-by: Markus <m4rkusxxl@xxxxxx> Cc: Ming Lei <tom.leiming@xxxxxxxxx> Fix: 841c1316c7da(md: raid1: improve write behind) Cc: stable@xxxxxxxxxxxxxxx (4.12+) Signed-off-by: Shaohua Li <shli@xxxxxx> --- drivers/md/raid1.c | 30 ++++++++++-------------------- 1 file changed, 10 insertions(+), 20 deletions(-) diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c index 8387eb1540cd..5622f521830b 100644 --- a/drivers/md/raid1.c +++ b/drivers/md/raid1.c @@ -484,10 +484,6 @@ static void raid1_end_write_request(struct bio *bio) } if (behind) { - /* we release behind master bio when all write are done */ - if (r1_bio->behind_master_bio == bio) - to_put = NULL; - if (test_bit(WriteMostly, &rdev->flags)) atomic_dec(&r1_bio->behind_remaining); @@ -1080,7 +1076,7 @@ static void unfreeze_array(struct r1conf *conf) wake_up(&conf->wait_barrier); } -static struct bio *alloc_behind_master_bio(struct r1bio *r1_bio, +static void alloc_behind_master_bio(struct r1bio *r1_bio, struct bio *bio) { int size = bio->bi_iter.bi_size; @@ -1090,7 +1086,7 @@ static struct bio *alloc_behind_master_bio(struct r1bio *r1_bio, behind_bio = bio_alloc_mddev(GFP_NOIO, vcnt, r1_bio->mddev); if (!behind_bio) - goto fail; + return; /* discard op, we don't support writezero/writesame yet */ if (!bio_has_data(bio)) @@ -1115,14 +1111,13 @@ static struct bio *alloc_behind_master_bio(struct r1bio *r1_bio, r1_bio->behind_master_bio = behind_bio;; set_bit(R1BIO_BehindIO, &r1_bio->state); - return behind_bio; + return; free_pages: pr_debug("%dB behind alloc failed, doing sync I/O\n", bio->bi_iter.bi_size); bio_free_pages(behind_bio); -fail: - return behind_bio; + bio_put(behind_bio); } struct raid1_plug_cb { @@ -1475,7 +1470,7 @@ static void raid1_write_request(struct mddev *mddev, struct bio *bio, (atomic_read(&bitmap->behind_writes) < mddev->bitmap_info.max_write_behind) && !waitqueue_active(&bitmap->behind_wait)) { - mbio = alloc_behind_master_bio(r1_bio, bio); + alloc_behind_master_bio(r1_bio, bio); } bitmap_startwrite(bitmap, r1_bio->sector, @@ -1485,14 +1480,11 @@ static void raid1_write_request(struct mddev *mddev, struct bio *bio, first_clone = 0; } - if (!mbio) { - if (r1_bio->behind_master_bio) - mbio = bio_clone_fast(r1_bio->behind_master_bio, - GFP_NOIO, - mddev->bio_set); - else - mbio = bio_clone_fast(bio, GFP_NOIO, mddev->bio_set); - } + if (r1_bio->behind_master_bio) + mbio = bio_clone_fast(r1_bio->behind_master_bio, + GFP_NOIO, mddev->bio_set); + else + mbio = bio_clone_fast(bio, GFP_NOIO, mddev->bio_set); if (r1_bio->behind_master_bio) { if (test_bit(WriteMostly, &conf->mirrors[i].rdev->flags)) @@ -2346,8 +2338,6 @@ static int narrow_write_error(struct r1bio *r1_bio, int i) wbio = bio_clone_fast(r1_bio->behind_master_bio, GFP_NOIO, mddev->bio_set); - /* We really need a _all clone */ - wbio->bi_iter = (struct bvec_iter){ 0 }; } else { wbio = bio_clone_fast(r1_bio->master_bio, GFP_NOIO, mddev->bio_set); -- 2.11.0 -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
