md/raid1: free r1_bio when REQ_NOWAIT is set and read would block on retry

When a read is retried, raid1_read_request() may be called with a
pre-allocated r1_bio. If wait_read_barrier() fails for a REQ_NOWAIT
read, the bio is completed and the function returns immediately. In this
case the existing r1_bio is leaked.

This fixes a leak of pre-allocated r1_bio structures for retried reads.

Fixes: 5aa705039c4f ("md: raid1 add nowait support")
Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Closes: https://sashiko.dev/#/patchset/20260611083514.754922-1-abd.masalkhi@gmail.com?part=1
Signed-off-by: Abd-Alrhman Masalkhi <abd.masalkhi@gmail.com>
Link: https://patch.msgid.link/20260611101350.759154-1-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 e2a50816e5a06de8693953790a0b4344a768bac2..41d9094fa50a7093c46e73da9c2acbebf880e220 100644 (file)
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -1363,6 +1363,12 @@ static void raid1_read_request(struct mddev *mddev, struct bio *bio,
         */
        if (!wait_read_barrier(conf, bio->bi_iter.bi_sector, nowait)) {
                bio_wouldblock_error(bio);
+
+               if (r1bio_existed) {
+                       set_bit(R1BIO_Returned, &r1_bio->state);
+                       raid_end_bio_io(r1_bio);
+               }
+
                return;
        }