Commit 4c3f4838 authored by Mike Snitzer's avatar Mike Snitzer
Browse files

dm mpath: enhance queue_if_no_path debugging 



Add more DMDEBUG that shows arguments passed and caller, and another
that shows state of related flags at end of queue_if_no_path().

Also add queue_if_no_path DMDEBUG to multipath_resume().

Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
parent 553ec94c

drivers/md/dm-mpath.c

+23 −7
Original line number Diff line number Diff line
@@ -692,10 +692,14 @@ static void process_queued_bios(struct work_struct *work) 
 * If we run out of usable paths, should we queue I/O or error it?

 */

static int queue_if_no_path(struct multipath *m, bool queue_if_no_path,

			    bool save_old_value)

			    bool save_old_value, const char *caller)

{

	unsigned long flags;

	bool queue_if_no_path_bit, saved_queue_if_no_path_bit;

	const char *dm_dev_name = dm_device_name(dm_table_get_md(m->ti->table));



	DMDEBUG("%s: %s caller=%s queue_if_no_path=%d save_old_value=%d",

		dm_dev_name, __func__, caller, queue_if_no_path, save_old_value);



	spin_lock_irqsave(&m->lock, flags);
@@ -705,7 +709,7 @@ static int queue_if_no_path(struct multipath *m, bool queue_if_no_path, 
	if (save_old_value) {

		if (unlikely(!queue_if_no_path_bit && saved_queue_if_no_path_bit)) {

			DMERR("%s: QIFNP disabled but saved as enabled, saving again loses state, not saving!",

			      dm_device_name(dm_table_get_md(m->ti->table)));

			      dm_dev_name);

		} else

			assign_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &m->flags, queue_if_no_path_bit);

	} else if (!queue_if_no_path && saved_queue_if_no_path_bit) {
@@ -714,6 +718,12 @@ static int queue_if_no_path(struct multipath *m, bool queue_if_no_path, 
	}

	assign_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags, queue_if_no_path);



	DMDEBUG("%s: after %s changes; QIFNP = %d; SQIFNP = %d; DNFS = %d",

		dm_dev_name, __func__,

		test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags),

		test_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &m->flags),

		dm_noflush_suspending(m->ti));



	spin_unlock_irqrestore(&m->lock, flags);



	if (!queue_if_no_path) {
@@ -734,7 +744,7 @@ static void queue_if_no_path_timeout_work(struct timer_list *t) 
	struct mapped_device *md = dm_table_get_md(m->ti->table);



	DMWARN("queue_if_no_path timeout on %s, failing queued IO", dm_device_name(md));

	queue_if_no_path(m, false, false);

	queue_if_no_path(m, false, false, __func__);

}



/*
@@ -1074,7 +1084,7 @@ static int parse_features(struct dm_arg_set *as, struct multipath *m) 
		argc--;



		if (!strcasecmp(arg_name, "queue_if_no_path")) {

			r = queue_if_no_path(m, true, false);

			r = queue_if_no_path(m, true, false, __func__);

			continue;

		}
@@ -1678,7 +1688,7 @@ static void multipath_presuspend(struct dm_target *ti) 


	/* FIXME: bio-based shouldn't need to always disable queue_if_no_path */

	if (m->queue_mode == DM_TYPE_BIO_BASED || !dm_noflush_suspending(m->ti))

		queue_if_no_path(m, false, true);

		queue_if_no_path(m, false, true, __func__);

}



static void multipath_postsuspend(struct dm_target *ti)
@@ -1703,6 +1713,12 @@ static void multipath_resume(struct dm_target *ti) 
		set_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags);

		clear_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &m->flags);

	}



	DMDEBUG("%s: %s finished; QIFNP = %d; SQIFNP = %d",

		dm_device_name(dm_table_get_md(m->ti->table)), __func__,

		test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags),

		test_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &m->flags));



	spin_unlock_irqrestore(&m->lock, flags);

}
@@ -1862,13 +1878,13 @@ static int multipath_message(struct dm_target *ti, unsigned argc, char **argv, 


	if (argc == 1) {

		if (!strcasecmp(argv[0], "queue_if_no_path")) {

			r = queue_if_no_path(m, true, false);

			r = queue_if_no_path(m, true, false, __func__);

			spin_lock_irqsave(&m->lock, flags);

			enable_nopath_timeout(m);

			spin_unlock_irqrestore(&m->lock, flags);

			goto out;

		} else if (!strcasecmp(argv[0], "fail_if_no_path")) {

			r = queue_if_no_path(m, false, false);

			r = queue_if_no_path(m, false, false, __func__);

			disable_nopath_timeout(m);

			goto out;

		}