From: Abd-Alrhman Masalkhi <abd.masalkhi@gmail.com>
Date: Fri, 1 May 2026 11:46:51 +0000 (+0200)
Subject: md/raid1,raid10: fix bio accounting for split md cloned bios
X-Git-Url: http://git.ipfire.org/gitweb/?a=commitdiff_plain;h=ba976e3501111d11c550848b3b7341a73035f582;p=thirdparty%2Fkernel%2Flinux.git

md/raid1,raid10: fix bio accounting for split md cloned bios

Use md_cloned_bio() to control bio accounting instead of relying
on r1bio_existed in raid1 or the io_accounting flag in raid10.

The previous logic does not reliably reflect whether a bio is an
md cloned bio. When a failed bio is split and resubmitted via
bio_submit_split_bioset() on the error path, this can lead to either
double accounting for md cloned bios, or missing accounting for bios
returned from bio_submit_split_bioset()

Fix this by using md_cloned_bio() to detect md cloned bios and
skip accounting accordingly.

Fixes: bb2a9acefaf9 ("md/raid1: switch to use md_account_bio() for io accounting")
Fixes: 820455238366 ("md/raid10: switch to use md_account_bio() for io accounting")
Signed-off-by: Abd-Alrhman Masalkhi <abd.masalkhi@gmail.com>
Reviewed-by: Xiao Ni <xiao@kernel.org>
Link: https://patch.msgid.link/20260501114652.590037-4-abd.masalkhi@gmail.com
Signed-off-by: Yu Kuai <yukuai@fygo.io>
---

diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 22458df5069e9..603aa09088f05 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -1418,7 +1418,7 @@ static void raid1_read_request(struct mddev *mddev, struct bio *bio,
 	}
 
 	r1_bio->read_disk = rdisk;
-	if (!r1bio_existed) {
+	if (likely(!md_cloned_bio(mddev, bio))) {
 		md_account_bio(mddev, &bio);
 		r1_bio->master_bio = bio;
 	}
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index b38a0ccd4661a..5bd7698e0a1b5 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -1146,7 +1146,7 @@ static bool regular_request_wait(struct mddev *mddev, struct r10conf *conf,
 }
 
 static void raid10_read_request(struct mddev *mddev, struct bio *bio,
-				struct r10bio *r10_bio, bool io_accounting)
+				struct r10bio *r10_bio)
 {
 	struct r10conf *conf = mddev->private;
 	struct bio *read_bio;
@@ -1226,7 +1226,7 @@ static void raid10_read_request(struct mddev *mddev, struct bio *bio,
 	}
 	slot = r10_bio->read_slot;
 
-	if (io_accounting) {
+	if (likely(!md_cloned_bio(mddev, bio))) {
 		md_account_bio(mddev, &bio);
 		r10_bio->master_bio = bio;
 	}
@@ -1552,7 +1552,7 @@ static void __make_request(struct mddev *mddev, struct bio *bio, int sectors)
 			conf->geo.raid_disks);
 
 	if (bio_data_dir(bio) == READ)
-		raid10_read_request(mddev, bio, r10_bio, true);
+		raid10_read_request(mddev, bio, r10_bio);
 	else
 		raid10_write_request(mddev, bio, r10_bio);
 }
@@ -2867,7 +2867,7 @@ static void handle_read_error(struct mddev *mddev, struct r10bio *r10_bio)
 
 	rdev_dec_pending(rdev, mddev);
 	r10_bio->state = 0;
-	raid10_read_request(mddev, r10_bio->master_bio, r10_bio, false);
+	raid10_read_request(mddev, r10_bio->master_bio, r10_bio);
 	/*
 	 * allow_barrier after re-submit to ensure no sync io
 	 * can be issued while regular io pending.