Commit 16d56e2f authored by Shaohua Li's avatar Shaohua Li
Browse files

md/raid1: fix writebehind bio clone 

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-and-tested-by: default avatarMarkus <m4rkusxxl@web.de>
Reviewed-by: default avatarMing Lei <ming.lei@redhat.com>
Fix: 841c1316(md: raid1: improve write behind)
Cc: stable@vger.kernel.org (4.12+)
Signed-off-by: default avatarShaohua Li <shli@fb.com>
parent be453e77

drivers/md/raid1.c

+13 −21
Original line number Diff line number Diff line
@@ -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;
@@ -1090,11 +1086,13 @@ 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))

	if (!bio_has_data(bio)) {

		behind_bio->bi_iter.bi_size = size;

		goto skip_copy;

	}



	while (i < vcnt && size) {

		struct page *page;
@@ -1115,14 +1113,13 @@ skip_copy: 
	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 +1472,7 @@ 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 +1482,11 @@ 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);

					      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 +2340,6 @@ 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);

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