diff options
| -rw-r--r-- | drivers/md/dm-mpath.c | 118 |
1 files changed, 78 insertions, 40 deletions
diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c index 53861ad5dd1d..12b7bcae490c 100644 --- a/drivers/md/dm-mpath.c +++ b/drivers/md/dm-mpath.c @@ -79,6 +79,7 @@ struct multipath { struct pgpath *current_pgpath; struct priority_group *current_pg; struct priority_group *next_pg; /* Switch to this PG if set */ + struct priority_group *last_probed_pg; atomic_t nr_valid_paths; /* Total number of usable paths */ unsigned int nr_priority_groups; @@ -87,6 +88,7 @@ struct multipath { const char *hw_handler_name; char *hw_handler_params; wait_queue_head_t pg_init_wait; /* Wait for pg_init completion */ + wait_queue_head_t probe_wait; /* Wait for probing paths */ unsigned int pg_init_retries; /* Number of times to retry pg_init */ unsigned int pg_init_delay_msecs; /* Number of msecs before pg_init retry */ atomic_t pg_init_in_progress; /* Only one pg_init allowed at once */ @@ -100,6 +102,7 @@ struct multipath { struct bio_list queued_bios; struct timer_list nopath_timer; /* Timeout for queue_if_no_path */ + bool is_suspending; }; /* @@ -132,6 +135,8 @@ static void queue_if_no_path_timeout_work(struct timer_list *t); #define MPATHF_PG_INIT_DISABLED 4 /* pg_init is not currently allowed */ #define MPATHF_PG_INIT_REQUIRED 5 /* pg_init needs calling? */ #define MPATHF_PG_INIT_DELAY_RETRY 6 /* Delay pg_init retry? */ +#define MPATHF_DELAY_PG_SWITCH 7 /* Delay switching pg if it still has paths */ +#define MPATHF_NEED_PG_SWITCH 8 /* Need to switch pgs after the delay has ended */ static bool mpath_double_check_test_bit(int MPATHF_bit, struct multipath *m) { @@ -254,6 +259,7 @@ static int alloc_multipath_stage2(struct dm_target *ti, struct multipath *m) atomic_set(&m->pg_init_count, 0); m->pg_init_delay_msecs = DM_PG_INIT_DELAY_DEFAULT; init_waitqueue_head(&m->pg_init_wait); + init_waitqueue_head(&m->probe_wait); return 0; } @@ -413,13 +419,21 @@ static struct pgpath *choose_pgpath(struct multipath *m, size_t nr_bytes) goto failed; } + /* Don't change PG until it has no remaining paths */ + pg = READ_ONCE(m->current_pg); + if (pg) { + pgpath = choose_path_in_pg(m, pg, nr_bytes); + if (!IS_ERR_OR_NULL(pgpath)) + return pgpath; + } + /* Were we instructed to switch PG? */ if (READ_ONCE(m->next_pg)) { spin_lock_irqsave(&m->lock, flags); pg = m->next_pg; if (!pg) { spin_unlock_irqrestore(&m->lock, flags); - goto check_current_pg; + goto check_all_pgs; } m->next_pg = NULL; spin_unlock_irqrestore(&m->lock, flags); @@ -427,16 +441,7 @@ static struct pgpath *choose_pgpath(struct multipath *m, size_t nr_bytes) if (!IS_ERR_OR_NULL(pgpath)) return pgpath; } - - /* Don't change PG until it has no remaining paths */ -check_current_pg: - pg = READ_ONCE(m->current_pg); - if (pg) { - pgpath = choose_path_in_pg(m, pg, nr_bytes); - if (!IS_ERR_OR_NULL(pgpath)) - return pgpath; - } - +check_all_pgs: /* * Loop through priority groups until we find a valid path. * First time we skip PGs marked 'bypassed'. @@ -1439,15 +1444,19 @@ static int action_dev(struct multipath *m, dev_t dev, action_fn action) * Temporarily try to avoid having to use the specified PG */ static void bypass_pg(struct multipath *m, struct priority_group *pg, - bool bypassed) + bool bypassed, bool can_be_delayed) { unsigned long flags; spin_lock_irqsave(&m->lock, flags); pg->bypassed = bypassed; - m->current_pgpath = NULL; - m->current_pg = NULL; + if (can_be_delayed && test_bit(MPATHF_DELAY_PG_SWITCH, &m->flags)) + set_bit(MPATHF_NEED_PG_SWITCH, &m->flags); + else { + m->current_pgpath = NULL; + m->current_pg = NULL; + } spin_unlock_irqrestore(&m->lock, flags); @@ -1476,8 +1485,12 @@ static int switch_pg_num(struct multipath *m, const char *pgstr) if (--pgnum) continue; - m->current_pgpath = NULL; - m->current_pg = NULL; + if (test_bit(MPATHF_DELAY_PG_SWITCH, &m->flags)) + set_bit(MPATHF_NEED_PG_SWITCH, &m->flags); + else { + m->current_pgpath = NULL; + m->current_pg = NULL; + } m->next_pg = pg; } spin_unlock_irqrestore(&m->lock, flags); @@ -1507,7 +1520,7 @@ static int bypass_pg_num(struct multipath *m, const char *pgstr, bool bypassed) break; } - bypass_pg(m, pg, bypassed); + bypass_pg(m, pg, bypassed, true); return 0; } @@ -1561,7 +1574,7 @@ static void pg_init_done(void *data, int errors) * Probably doing something like FW upgrade on the * controller so try the other pg. */ - bypass_pg(m, pg, true); + bypass_pg(m, pg, true, false); break; case SCSI_DH_RETRY: /* Wait before retrying. */ @@ -1741,7 +1754,11 @@ done: static void multipath_presuspend(struct dm_target *ti) { struct multipath *m = ti->private; + unsigned long flags; + spin_lock_irqsave(&m->lock, flags); + m->is_suspending = true; + spin_unlock_irqrestore(&m->lock, flags); /* 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, __func__); @@ -1765,6 +1782,7 @@ static void multipath_resume(struct dm_target *ti) unsigned long flags; spin_lock_irqsave(&m->lock, flags); + m->is_suspending = false; if (test_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &m->flags)) { set_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags); clear_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &m->flags); @@ -1845,10 +1863,10 @@ static void multipath_status(struct dm_target *ti, status_type_t type, DMEMIT("%u ", m->nr_priority_groups); - if (m->next_pg) - pg_num = m->next_pg->pg_num; - else if (m->current_pg) + if (m->current_pg) pg_num = m->current_pg->pg_num; + else if (m->next_pg) + pg_num = m->next_pg->pg_num; else pg_num = (m->nr_priority_groups ? 1 : 0); @@ -2077,35 +2095,55 @@ out: static int probe_active_paths(struct multipath *m) { struct pgpath *pgpath; - struct priority_group *pg; + struct priority_group *pg = NULL; unsigned long flags; int r = 0; - mutex_lock(&m->work_mutex); - spin_lock_irqsave(&m->lock, flags); - if (test_bit(MPATHF_QUEUE_IO, &m->flags)) - pg = NULL; - else - pg = m->current_pg; + if (test_bit(MPATHF_DELAY_PG_SWITCH, &m->flags)) { + wait_event_lock_irq(m->probe_wait, + !test_bit(MPATHF_DELAY_PG_SWITCH, &m->flags), + m->lock); + /* + * if we waited because a probe was already in progress, + * and it probed the current active pathgroup, don't + * reprobe. Just return the number of valid paths + */ + if (m->current_pg == m->last_probed_pg) + goto skip_probe; + } + if (!m->current_pg || m->is_suspending || + test_bit(MPATHF_QUEUE_IO, &m->flags)) + goto skip_probe; + set_bit(MPATHF_DELAY_PG_SWITCH, &m->flags); + pg = m->last_probed_pg = m->current_pg; spin_unlock_irqrestore(&m->lock, flags); - if (pg) { - list_for_each_entry(pgpath, &pg->pgpaths, list) { - if (!pgpath->is_active) - continue; + list_for_each_entry(pgpath, &pg->pgpaths, list) { + if (pg != READ_ONCE(m->current_pg) || + READ_ONCE(m->is_suspending)) + goto out; + if (!pgpath->is_active) + continue; - r = probe_path(pgpath); - if (r < 0) - goto out; - } + r = probe_path(pgpath); + if (r < 0) + goto out; } - if (!atomic_read(&m->nr_valid_paths)) - r = -ENOTCONN; - out: - mutex_unlock(&m->work_mutex); + spin_lock_irqsave(&m->lock, flags); + clear_bit(MPATHF_DELAY_PG_SWITCH, &m->flags); + if (test_and_clear_bit(MPATHF_NEED_PG_SWITCH, &m->flags)) { + m->current_pgpath = NULL; + m->current_pg = NULL; + } +skip_probe: + if (r == 0 && !atomic_read(&m->nr_valid_paths)) + r = -ENOTCONN; + spin_unlock_irqrestore(&m->lock, flags); + if (pg) + wake_up(&m->probe_wait); return r; } |