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authorYu Kuai <yukuai3@huawei.com>2024-05-22 04:03:08 +0800
committerJens Axboe <axboe@kernel.dk>2024-05-21 19:37:33 -0600
commit9a42891c35d50a8472b42c61256867b4dfcc1941 (patch)
treede574c834ac09c8009376e45c158bd82f09e8d72 /block
parentf0eab3e8d1530b87f3523cee060004dd513a6d2b (diff)
block: fix lost bio for plug enabled bio based device
With the following two conditions, bio will be lost: 1) blk plug is not enabled, for example, __blkdev_direct_IO_simple() and __blkdev_direct_IO_async(); 2) bio plug is enabled, for example write IO for raid1/raid10 while bitmap is enabled; Root cause is that blk_finish_plug() will add the bio to curent->bio_list, while such bio will not be handled: __submit_bio_noacct current->bio_list = bio_list_on_stack; blk_start_plug do { dm_submit_bio md_handle_request raid10_write_request -> generate new bio for underlying disks raid1_add_bio_to_plug -> bio is added to plug } while ((bio = bio_list_pop(&bio_list_on_stack[0]))) -> previous bio are all handled blk_finish_plug raid10_unplug raid1_submit_write submit_bio_noacct if (current->bio_list) bio_list_add(&current->bio_list[0], bio) -> add new bio current->bio_list = NULL -> new bio is lost Fix the problem by moving the plug into the while loop, so that current->bio_list will still be handled after blk_finish_plug(). By the way, enable plug for raid1/raid10 in this case will also prevent delay IO handling into daemon thread, which should also improve IO performance. Fixes: 060406c61c7c ("block: add plug while submitting IO") Reported-by: Changhui Zhong <czhong@redhat.com> Closes: https://lore.kernel.org/all/CAGVVp+Xsmzy2G9YuEatfMT6qv1M--YdOCQ0g7z7OVmcTbBxQAg@mail.gmail.com/ Signed-off-by: Yu Kuai <yukuai3@huawei.com> Tested-by: Changhui Zhong <czhong@redhat.com> Link: https://lore.kernel.org/r/20240521200308.983986-1-yukuai1@huaweicloud.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
-rw-r--r--block/blk-core.c13
1 files changed, 7 insertions, 6 deletions
diff --git a/block/blk-core.c b/block/blk-core.c
index 01186333c88e..dd29d5465af6 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -613,9 +613,14 @@ static inline blk_status_t blk_check_zone_append(struct request_queue *q,
static void __submit_bio(struct bio *bio)
{
+ /* If plug is not used, add new plug here to cache nsecs time. */
+ struct blk_plug plug;
+
if (unlikely(!blk_crypto_bio_prep(&bio)))
return;
+ blk_start_plug(&plug);
+
if (!bio->bi_bdev->bd_has_submit_bio) {
blk_mq_submit_bio(bio);
} else if (likely(bio_queue_enter(bio) == 0)) {
@@ -624,6 +629,8 @@ static void __submit_bio(struct bio *bio)
disk->fops->submit_bio(bio);
blk_queue_exit(disk->queue);
}
+
+ blk_finish_plug(&plug);
}
/*
@@ -648,13 +655,11 @@ static void __submit_bio(struct bio *bio)
static void __submit_bio_noacct(struct bio *bio)
{
struct bio_list bio_list_on_stack[2];
- struct blk_plug plug;
BUG_ON(bio->bi_next);
bio_list_init(&bio_list_on_stack[0]);
current->bio_list = bio_list_on_stack;
- blk_start_plug(&plug);
do {
struct request_queue *q = bdev_get_queue(bio->bi_bdev);
@@ -688,23 +693,19 @@ static void __submit_bio_noacct(struct bio *bio)
bio_list_merge(&bio_list_on_stack[0], &bio_list_on_stack[1]);
} while ((bio = bio_list_pop(&bio_list_on_stack[0])));
- blk_finish_plug(&plug);
current->bio_list = NULL;
}
static void __submit_bio_noacct_mq(struct bio *bio)
{
struct bio_list bio_list[2] = { };
- struct blk_plug plug;
current->bio_list = bio_list;
- blk_start_plug(&plug);
do {
__submit_bio(bio);
} while ((bio = bio_list_pop(&bio_list[0])));
- blk_finish_plug(&plug);
current->bio_list = NULL;
}