[PATCH 5.0 080/117] block: fix the return errno for direct IO

Greg Kroah-Hartman
2019-04-15T19:13:18Z

From: Jason Yan <yanaijie@huawei.com>

commit a89afe58f1a74aac768a5eb77af95ef4ee15beaa upstream.

If the last bio returned is not dio->bio, the status of the bio will
not assigned to dio->bio if it is error. This will cause the whole IO
status wrong.

ksoftirqd/21-117 [021] ..s. 4017.966090: 8,0 C N 4883648 [0]
<idle>-0 [018] ..s. 4017.970888: 8,0 C WS 4924800 + 1024 [0]
<idle>-0 [018] ..s. 4017.970909: 8,0 D WS 4935424 + 1024 [<idle>]
<idle>-0 [018] ..s. 4017.970924: 8,0 D WS 4936448 + 321 [<idle>]
ksoftirqd/21-117 [021] ..s. 4017.995033: 8,0 C R 4883648 + 336 [65475]
ksoftirqd/21-117 [021] d.s. 4018.001988: myprobe1: (blkdev_bio_end_io+0x0/0x168) bi_status=7
ksoftirqd/21-117 [021] d.s. 4018.001992: myprobe: (aio_complete_rw+0x0/0x148) x0=0xffff802f2595ad80 res=0x12a000 res2=0x0

We always have to assign bio->bi_status to dio->bio.bi_status because we
will only check dio->bio.bi_status when we return the whole IO to
the upper layer.

Fixes: 542ff7bf18c6 ("block: new direct I/O implementation")
Cc: stable@vger.kernel.org
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jason Yan <yanaijie@huawei.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
fs/block_dev.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -298,10 +298,10 @@ static void blkdev_bio_end_io(struct bio
struct blkdev_dio *dio = bio->bi_private;
bool should_dirty = dio->should_dirty;

- if (dio->multi_bio && !atomic_dec_and_test(&dio->ref)) {
- if (bio->bi_status && !dio->bio.bi_status)
- dio->bio.bi_status = bio->bi_status;
- } else {
+ if (bio->bi_status && !dio->bio.bi_status)
+ dio->bio.bi_status = bio->bi_status;
+
+ if (!dio->multi_bio || atomic_dec_and_test(&dio->ref)) {
if (!dio->is_sync) {
struct kiocb *iocb = dio->iocb;
ssize_t ret;