FAILED: patch "[PATCH] drbd: correctly submit flush bio on barrier" failed to apply to 4.14-stable tree

The patch below does not apply to the 4.14-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-4.14.y
git checkout FETCH_HEAD
git cherry-pick -x 3899d94e3831ee07ea6821c032dc297aec80586a
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2023050713-unshaved-harmonica-4f00@gregkh' --subject-prefix 'PATCH 4.14.y' HEAD^..

Possible dependencies:

3899d94e3831 ("drbd: correctly submit flush bio on barrier") 07888c665b40 ("block: pass a block_device and opf to bio_alloc") b77c88c2100c ("block: pass a block_device and opf to bio_alloc_kiocb") 609be1066731 ("block: pass a block_device and opf to bio_alloc_bioset") 0a3140ea0fae ("block: pass a block_device and opf to blk_next_bio") 3b005bf6acf0 ("block: move blk_next_bio to bio.c") 7d8d0c658d48 ("xen-blkback: bio_alloc can't fail if it is allow to sleep") d7b78de2b155 ("rnbd-srv: remove struct rnbd_dev_blk_io") 1fe0640ff94f ("rnbd-srv: simplify bio mapping in process_rdma") 4b1dc86d1857 ("drbd: bio_alloc can't fail if it is allow to sleep") 3f868c09ea8f ("dm-crypt: remove clone_init")
53db984e004c ("dm: bio_alloc can't fail if it is allowed to sleep") 39146b6f66ba ("ntfs3: remove ntfs_alloc_bio")
5d2ca2132f88 ("nfs/blocklayout: remove bl_alloc_init_bio") f0d911927b3c ("nilfs2: remove nilfs_alloc_seg_bio") d5f68a42da7a ("fs: remove mpage_alloc")
ae4c81644e91 ("RDMA/rtrs-srv: Rename rtrs_srv_sess to rtrs_srv_path") d9372794717f ("RDMA/rtrs: Rename rtrs_sess to rtrs_path") 512b7931ad05 ("Merge branch 'akpm' (patches from Andrew)")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 3899d94e3831ee07ea6821c032dc297aec80586a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Christoph=20B=C3=B6hmwalder?=
<[email protected]>
Date: Wed, 3 May 2023 14:19:37 +0200
Subject: [PATCH] drbd: correctly submit flush bio on barrier
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

When we receive a flush command (or "barrier" in DRBD), we currently use a REQ_OP_FLUSH with the REQ_PREFLUSH flag set.

The correct way to submit a flush bio is by using a REQ_OP_WRITE without any data, and set the REQ_PREFLUSH flag.

Since commit b4a6bb3a67aa ("block: add a sanity check for non-write flush/fua bios"), this triggers a warning in the block layer, but this has been broken for quite some time before that.

So use the correct set of flags to actually make the flush happen.

index e54404c632e7..34b112752ab1 100644
@@ -1283,7 +1283,7 @@ static void one_flush_endio(struct bio *bio)
 static void submit_one_flush(struct drbd_device *device, struct issue_flush_context *ctx)
 {
 	struct bio *bio = bio_alloc(device->ldev->backing_bdev, 0,
-				    REQ_OP_FLUSH | REQ_PREFLUSH, GFP_NOIO);
+				    REQ_OP_WRITE | REQ_PREFLUSH, GFP_NOIO);
 	struct one_flush_context *octx = kmalloc(sizeof(*octx), GFP_NOIO);
 
 	if (!octx) {

When we receive a flush command (or "barrier" in DRBD), we currently use a REQ_OP_FLUSH with the REQ_PREFLUSH flag set.

The correct way to submit a flush bio is by using a REQ_OP_WRITE without any data, and set the REQ_PREFLUSH flag.

Since commit b4a6bb3a67aa ("block: add a sanity check for non-write flush/fua bios"), this triggers a warning in the block layer, but this has been broken for quite some time before that.

So use the correct set of flags to actually make the flush happen.

---
 drivers/block/drbd/drbd_receiver.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

index a7c180426c60..5a63010f2af3 100644
@@ -1309,7 +1309,7 @@ static void submit_one_flush(struct drbd_device *device, struct issue_flush_cont
 	bio_set_dev(bio, device->ldev->backing_bdev);
 	bio->bi_private = octx;
 	bio->bi_end_io = one_flush_endio;
-	bio->bi_opf = REQ_OP_FLUSH | REQ_PREFLUSH;
+	bio->bi_opf = REQ_OP_WRITE | REQ_PREFLUSH;
 
 	device->flush_jif = jiffies;
 	set_bit(FLUSH_PENDING, &device->flags);

2.39.2