Commit 0e91d3a6 authored by Brian Foster's avatar Brian Foster Committed by Kent Overstreet
Browse files

bcachefs: fix odebug warn and lockdep splat due to on-stack rhashtable 



Guenter Roeck reports a lockdep splat and DEBUG_OBJECTS_WORK related
warning when bch2_copygc_thread() initializes its rhashtable. The
lockdep splat relates to a warning print caused by the fact that the
rhashtable exists on the stack but is not annotated as so. This is
something that could be addressed by INIT_WORK_ONSTACK(), but
rhashtable doesn't expose that control and probably isnt worth the
churn for just one user. Instead, dynamically allocate the
buckets_in_flight structure and avoid the splat that way.

Reported-by: default avatarGuenter Roeck <linux@roeck-us.net>
Tested-by: default avatarGuenter Roeck <linux@roeck-us.net>
Signed-off-by: default avatarBrian Foster <bfoster@redhat.com>
Signed-off-by: default avatarKent Overstreet <kent.overstreet@linux.dev>
parent e0fb0dcc

fs/bcachefs/movinggc.c

+14 −10
Original line number Diff line number Diff line
@@ -305,14 +305,16 @@ static int bch2_copygc_thread(void *arg) 
	struct moving_context ctxt;

	struct bch_move_stats move_stats;

	struct io_clock *clock = &c->io_clock[WRITE];

	struct buckets_in_flight buckets;

	struct buckets_in_flight *buckets;

	u64 last, wait;

	int ret = 0;



	memset(&buckets, 0, sizeof(buckets));



	ret = rhashtable_init(&buckets.table, &bch_move_bucket_params);

	buckets = kzalloc(sizeof(struct buckets_in_flight), GFP_KERNEL);

	if (!buckets)

		return -ENOMEM;

	ret = rhashtable_init(&buckets->table, &bch_move_bucket_params);

	if (ret) {

		kfree(buckets);

		bch_err_msg(c, ret, "allocating copygc buckets in flight");

		return ret;

	}
@@ -331,12 +333,12 @@ static int bch2_copygc_thread(void *arg) 
		cond_resched();



		if (!c->copy_gc_enabled) {

			move_buckets_wait(&ctxt, &buckets, true);

			move_buckets_wait(&ctxt, buckets, true);

			kthread_wait_freezable(c->copy_gc_enabled);

		}



		if (unlikely(freezing(current))) {

			move_buckets_wait(&ctxt, &buckets, true);

			move_buckets_wait(&ctxt, buckets, true);

			__refrigerator(false);

			continue;

		}
@@ -347,7 +349,7 @@ static int bch2_copygc_thread(void *arg) 
		if (wait > clock->max_slop) {

			c->copygc_wait_at = last;

			c->copygc_wait = last + wait;

			move_buckets_wait(&ctxt, &buckets, true);

			move_buckets_wait(&ctxt, buckets, true);

			trace_and_count(c, copygc_wait, c, wait, last + wait);

			bch2_kthread_io_clock_wait(clock, last + wait,

					MAX_SCHEDULE_TIMEOUT);
@@ -357,7 +359,7 @@ static int bch2_copygc_thread(void *arg) 
		c->copygc_wait = 0;



		c->copygc_running = true;

		ret = bch2_copygc(&ctxt, &buckets, &did_work);

		ret = bch2_copygc(&ctxt, buckets, &did_work);

		c->copygc_running = false;



		wake_up(&c->copygc_running_wq);
@@ -374,8 +376,10 @@ static int bch2_copygc_thread(void *arg) 
		}

	}



	move_buckets_wait(&ctxt, &buckets, true);

	rhashtable_destroy(&buckets.table);

	move_buckets_wait(&ctxt, buckets, true);



	rhashtable_destroy(&buckets->table);

	kfree(buckets);

	bch2_moving_ctxt_exit(&ctxt);

	bch2_move_stats_exit(&move_stats, c);