From 4c3f48380fedbd714fc95958f503c1b5adf3ee6b Mon Sep 17 00:00:00 2001 From: Mike Snitzer Date: Fri, 29 May 2020 15:59:13 -0400 Subject: [PATCH] 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: Mike Snitzer --- drivers/md/dm-mpath.c | 30 +++++++++++++++++++++++------- 1 file changed, 23 insertions(+), 7 deletions(-) diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c index bc846cf7b0d8..b17da3046611 100644 --- a/drivers/md/dm-mpath.c +++ b/drivers/md/dm-mpath.c @@ -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; }