md/raid10: fix leak of 'r10bio->remaining' for recovery

[ Upstream commit 26208a7cffd0c7cbf14237ccd20c7270b3ffeb7e ]

raid10_sync_request() will add 'r10bio->remaining' for both rdev and
replacement rdev. However, if the read io fails, recovery_request_write()
returns without issuing the write io, in this case, end_sync_request()
is only called once and 'remaining' is leaked, cause an io hang.

Fix the problem by decreasing 'remaining' according to if 'bio' and
'repl_bio' is valid.

Fixes: 24afd80d99f8 ("md/raid10: handle recovery of replacement devices.")
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20230310073855.1337560-5-yukuai1@huaweicloud.com
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index ab0eef8..e2bd0f8 100644 (file)
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -2613,11 +2613,22 @@ static void recovery_request_write(struct mddev *mddev, struct r10bio *r10_bio)
 {
        struct r10conf *conf = mddev->private;
        int d;
-       struct bio *wbio, *wbio2;
+       struct bio *wbio = r10_bio->devs[1].bio;
+       struct bio *wbio2 = r10_bio->devs[1].repl_bio;
+
+       /* Need to test wbio2->bi_end_io before we call
+        * submit_bio_noacct as if the former is NULL,
+        * the latter is free to free wbio2.
+        */
+       if (wbio2 && !wbio2->bi_end_io)
+               wbio2 = NULL;
 
        if (!test_bit(R10BIO_Uptodate, &r10_bio->state)) {
                fix_recovery_read_error(r10_bio);
-               end_sync_request(r10_bio);
+               if (wbio->bi_end_io)
+                       end_sync_request(r10_bio);
+               if (wbio2)
+                       end_sync_request(r10_bio);
                return;
        }
 
@@ -2626,14 +2637,6 @@ static void recovery_request_write(struct mddev *mddev, struct r10bio *r10_bio)
         * and submit the write request
         */
        d = r10_bio->devs[1].devnum;
-       wbio = r10_bio->devs[1].bio;
-       wbio2 = r10_bio->devs[1].repl_bio;
-       /* Need to test wbio2->bi_end_io before we call
-        * submit_bio_noacct as if the former is NULL,
-        * the latter is free to free wbio2.
-        */
-       if (wbio2 && !wbio2->bi_end_io)
-               wbio2 = NULL;
        if (wbio->bi_end_io) {
                atomic_inc(&conf->mirrors[d].rdev->nr_pending);
                md_sync_acct(conf->mirrors[d].rdev->bdev, bio_sectors(wbio));