bcache: fix I/O accounting leak in detached_dev_do_request

When a bcache device is detached, discard requests are completed
immediately. However, the I/O accounting started in
cached_dev_make_request() is not ended, leading to 100% disk
utilization reports in iostat. Add the missing bio_end_io_acct() call.

Fixes: cafe563 ("bcache: A block layer cache")
Signed-off-by: Shida Zhang <[email protected]>
Acked-by: Coly Li <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>

Author: Shida Zhang

drivers/md/bcache/request.c

@@ -1107,6 +1107,7 @@ static void detached_dev_do_request(struct bcache_device *d,
 
 	if (bio_op(orig_bio) == REQ_OP_DISCARD &&
 	    !bdev_max_discard_sectors(dc->bdev)) {
+		bio_end_io_acct(orig_bio, start_time);
 		bio_endio(orig_bio);
 		return;
 	}