[PATCH v2 3/4] md/raid10: fix writes_pending and barrier reference leaks on discard failures
From: Abd-Alrhman Masalkhi
Date: Sat Jun 13 2026 - 14:29:55 EST
raid10_make_request() acquires a writes_pending reference with
md_write_start() before calling raid10_handle_discard(). Several failure
paths in raid10_handle_discard() complete the bio and return without
releasing the corresponding reference, causing md_write_end() to be
skipped.
Call md_write_end() before returning from these failure paths to keep
writes_pending accounting balanced.
Additionally, discard split allocation failures can occur after
wait_barrier() succeeds. Those paths return without calling
allow_barrier(), leaking the associated barrier reference.
Release the barrier before returning from those paths.
Fixes: c9aa889b035f ("md: raid10 add nowait support")
Fixes: 4cf58d952909 ("md/raid10: Handle bio_split() errors")
Signed-off-by: Abd-Alrhman Masalkhi <abd.masalkhi@xxxxxxxxx>
---
Changes in v2:
- new patch.
---
drivers/md/raid10.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 5ad1b0c6207a..aacf160ee9f2 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -1639,6 +1639,7 @@ static int raid10_handle_discard(struct mddev *mddev, struct bio *bio)
if (!wait_barrier(conf, bio->bi_opf & REQ_NOWAIT)) {
bio_wouldblock_error(bio);
+ md_write_end(mddev);
return 0;
}
@@ -1681,6 +1682,8 @@ static int raid10_handle_discard(struct mddev *mddev, struct bio *bio)
if (IS_ERR(split)) {
bio->bi_status = errno_to_blk_status(PTR_ERR(split));
bio_endio(bio);
+ md_write_end(mddev);
+ allow_barrier(conf);
return 0;
}
@@ -1698,6 +1701,8 @@ static int raid10_handle_discard(struct mddev *mddev, struct bio *bio)
if (IS_ERR(split)) {
bio->bi_status = errno_to_blk_status(PTR_ERR(split));
bio_endio(bio);
+ md_write_end(mddev);
+ allow_barrier(conf);
return 0;
}
--
2.43.0