Commit d308ae0d authored by Ming Lei's avatar Ming Lei Committed by Jens Axboe
Browse files

block: drain queue after disk is removed from sysfs 



Before removing disk from sysfs, userspace still may change queue via
sysfs, such as switching elevator or setting wbt latency, both may
reinitialize wbt, then the warning in blk_free_queue_stats() will be
triggered since rq_qos_exit() is moved to del_gendisk().

Fixes the issue by moving draining queue & tearing down after disk is
removed from sysfs, at that time no one can come into queue's
store()/show().

Reported-by: default avatarYi Zhang <yi.zhang@redhat.com>
Tested-by: default avatarYi Zhang <yi.zhang@redhat.com>
Fixes: 8e141f9e ("block: drain file system I/O on del_gendisk")
Signed-off-by: default avatarMing Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20211026101204.2897166-1-ming.lei@redhat.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 9fbfabfd

block/genhd.c

+12 −10
Original line number Diff line number Diff line
@@ -588,16 +588,6 @@ void del_gendisk(struct gendisk *disk) 
	 * Prevent new I/O from crossing bio_queue_enter().

	 */

	blk_queue_start_drain(q);

	blk_mq_freeze_queue_wait(q);



	rq_qos_exit(q);

	blk_sync_queue(q);

	blk_flush_integrity();

	/*

	 * Allow using passthrough request again after the queue is torn down.

	 */

	blk_queue_flag_clear(QUEUE_FLAG_INIT_DONE, q);

	__blk_mq_unfreeze_queue(q, true);



	if (!(disk->flags & GENHD_FL_HIDDEN)) {

		sysfs_remove_link(&disk_to_dev(disk)->kobj, "bdi");
@@ -620,6 +610,18 @@ void del_gendisk(struct gendisk *disk) 
		sysfs_remove_link(block_depr, dev_name(disk_to_dev(disk)));

	pm_runtime_set_memalloc_noio(disk_to_dev(disk), false);

	device_del(disk_to_dev(disk));



	blk_mq_freeze_queue_wait(q);



	rq_qos_exit(q);

	blk_sync_queue(q);

	blk_flush_integrity();

	/*

	 * Allow using passthrough request again after the queue is torn down.

	 */

	blk_queue_flag_clear(QUEUE_FLAG_INIT_DONE, q);

	__blk_mq_unfreeze_queue(q, true);



}

EXPORT_SYMBOL(del_gendisk);