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- /*
- * Copyright (C) 2003 Sistina Software Limited.
- * Copyright (C) 2004-2005 Red Hat, Inc. All rights reserved.
- *
- * This file is released under the GPL.
- */
- #include <linux/device-mapper.h>
- #include "dm-rq.h"
- #include "dm-bio-record.h"
- #include "dm-path-selector.h"
- #include "dm-uevent.h"
- #include <linux/blkdev.h>
- #include <linux/ctype.h>
- #include <linux/init.h>
- #include <linux/mempool.h>
- #include <linux/module.h>
- #include <linux/pagemap.h>
- #include <linux/slab.h>
- #include <linux/time.h>
- #include <linux/timer.h>
- #include <linux/workqueue.h>
- #include <linux/delay.h>
- #include <scsi/scsi_dh.h>
- #include <linux/atomic.h>
- #include <linux/blk-mq.h>
- #define DM_MSG_PREFIX "multipath"
- #define DM_PG_INIT_DELAY_MSECS 2000
- #define DM_PG_INIT_DELAY_DEFAULT ((unsigned int) -1)
- #define QUEUE_IF_NO_PATH_TIMEOUT_DEFAULT 0
- static unsigned long queue_if_no_path_timeout_secs = QUEUE_IF_NO_PATH_TIMEOUT_DEFAULT;
- /* Path properties */
- struct pgpath {
- struct list_head list;
- struct priority_group *pg; /* Owning PG */
- unsigned int fail_count; /* Cumulative failure count */
- struct dm_path path;
- struct delayed_work activate_path;
- bool is_active:1; /* Path status */
- };
- #define path_to_pgpath(__pgp) container_of((__pgp), struct pgpath, path)
- /*
- * Paths are grouped into Priority Groups and numbered from 1 upwards.
- * Each has a path selector which controls which path gets used.
- */
- struct priority_group {
- struct list_head list;
- struct multipath *m; /* Owning multipath instance */
- struct path_selector ps;
- unsigned int pg_num; /* Reference number */
- unsigned int nr_pgpaths; /* Number of paths in PG */
- struct list_head pgpaths;
- bool bypassed:1; /* Temporarily bypass this PG? */
- };
- /* Multipath context */
- struct multipath {
- unsigned long flags; /* Multipath state flags */
- spinlock_t lock;
- enum dm_queue_mode queue_mode;
- struct pgpath *current_pgpath;
- struct priority_group *current_pg;
- struct priority_group *next_pg; /* Switch to this PG if set */
- atomic_t nr_valid_paths; /* Total number of usable paths */
- unsigned int nr_priority_groups;
- struct list_head priority_groups;
- const char *hw_handler_name;
- char *hw_handler_params;
- wait_queue_head_t pg_init_wait; /* Wait for pg_init completion */
- 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 */
- atomic_t pg_init_count; /* Number of times pg_init called */
- struct mutex work_mutex;
- struct work_struct trigger_event;
- struct dm_target *ti;
- struct work_struct process_queued_bios;
- struct bio_list queued_bios;
- struct timer_list nopath_timer; /* Timeout for queue_if_no_path */
- };
- /*
- * Context information attached to each io we process.
- */
- struct dm_mpath_io {
- struct pgpath *pgpath;
- size_t nr_bytes;
- u64 start_time_ns;
- };
- typedef int (*action_fn) (struct pgpath *pgpath);
- static struct workqueue_struct *kmultipathd, *kmpath_handlerd;
- static void trigger_event(struct work_struct *work);
- static void activate_or_offline_path(struct pgpath *pgpath);
- static void activate_path_work(struct work_struct *work);
- static void process_queued_bios(struct work_struct *work);
- static void queue_if_no_path_timeout_work(struct timer_list *t);
- /*-----------------------------------------------
- * Multipath state flags.
- *-----------------------------------------------*/
- #define MPATHF_QUEUE_IO 0 /* Must we queue all I/O? */
- #define MPATHF_QUEUE_IF_NO_PATH 1 /* Queue I/O if last path fails? */
- #define MPATHF_SAVED_QUEUE_IF_NO_PATH 2 /* Saved state during suspension */
- #define MPATHF_RETAIN_ATTACHED_HW_HANDLER 3 /* If there's already a hw_handler present, don't change it. */
- #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? */
- static bool mpath_double_check_test_bit(int MPATHF_bit, struct multipath *m)
- {
- bool r = test_bit(MPATHF_bit, &m->flags);
- if (r) {
- unsigned long flags;
- spin_lock_irqsave(&m->lock, flags);
- r = test_bit(MPATHF_bit, &m->flags);
- spin_unlock_irqrestore(&m->lock, flags);
- }
- return r;
- }
- /*-----------------------------------------------
- * Allocation routines
- *-----------------------------------------------*/
- static struct pgpath *alloc_pgpath(void)
- {
- struct pgpath *pgpath = kzalloc(sizeof(*pgpath), GFP_KERNEL);
- if (!pgpath)
- return NULL;
- pgpath->is_active = true;
- return pgpath;
- }
- static void free_pgpath(struct pgpath *pgpath)
- {
- kfree(pgpath);
- }
- static struct priority_group *alloc_priority_group(void)
- {
- struct priority_group *pg;
- pg = kzalloc(sizeof(*pg), GFP_KERNEL);
- if (pg)
- INIT_LIST_HEAD(&pg->pgpaths);
- return pg;
- }
- static void free_pgpaths(struct list_head *pgpaths, struct dm_target *ti)
- {
- struct pgpath *pgpath, *tmp;
- list_for_each_entry_safe(pgpath, tmp, pgpaths, list) {
- list_del(&pgpath->list);
- dm_put_device(ti, pgpath->path.dev);
- free_pgpath(pgpath);
- }
- }
- static void free_priority_group(struct priority_group *pg,
- struct dm_target *ti)
- {
- struct path_selector *ps = &pg->ps;
- if (ps->type) {
- ps->type->destroy(ps);
- dm_put_path_selector(ps->type);
- }
- free_pgpaths(&pg->pgpaths, ti);
- kfree(pg);
- }
- static struct multipath *alloc_multipath(struct dm_target *ti)
- {
- struct multipath *m;
- m = kzalloc(sizeof(*m), GFP_KERNEL);
- if (m) {
- INIT_LIST_HEAD(&m->priority_groups);
- spin_lock_init(&m->lock);
- atomic_set(&m->nr_valid_paths, 0);
- INIT_WORK(&m->trigger_event, trigger_event);
- mutex_init(&m->work_mutex);
- m->queue_mode = DM_TYPE_NONE;
- m->ti = ti;
- ti->private = m;
- timer_setup(&m->nopath_timer, queue_if_no_path_timeout_work, 0);
- }
- return m;
- }
- static int alloc_multipath_stage2(struct dm_target *ti, struct multipath *m)
- {
- if (m->queue_mode == DM_TYPE_NONE) {
- m->queue_mode = DM_TYPE_REQUEST_BASED;
- } else if (m->queue_mode == DM_TYPE_BIO_BASED) {
- INIT_WORK(&m->process_queued_bios, process_queued_bios);
- /*
- * bio-based doesn't support any direct scsi_dh management;
- * it just discovers if a scsi_dh is attached.
- */
- set_bit(MPATHF_RETAIN_ATTACHED_HW_HANDLER, &m->flags);
- }
- dm_table_set_type(ti->table, m->queue_mode);
- /*
- * Init fields that are only used when a scsi_dh is attached
- * - must do this unconditionally (really doesn't hurt non-SCSI uses)
- */
- set_bit(MPATHF_QUEUE_IO, &m->flags);
- atomic_set(&m->pg_init_in_progress, 0);
- atomic_set(&m->pg_init_count, 0);
- m->pg_init_delay_msecs = DM_PG_INIT_DELAY_DEFAULT;
- init_waitqueue_head(&m->pg_init_wait);
- return 0;
- }
- static void free_multipath(struct multipath *m)
- {
- struct priority_group *pg, *tmp;
- list_for_each_entry_safe(pg, tmp, &m->priority_groups, list) {
- list_del(&pg->list);
- free_priority_group(pg, m->ti);
- }
- kfree(m->hw_handler_name);
- kfree(m->hw_handler_params);
- mutex_destroy(&m->work_mutex);
- kfree(m);
- }
- static struct dm_mpath_io *get_mpio(union map_info *info)
- {
- return info->ptr;
- }
- static size_t multipath_per_bio_data_size(void)
- {
- return sizeof(struct dm_mpath_io) + sizeof(struct dm_bio_details);
- }
- static struct dm_mpath_io *get_mpio_from_bio(struct bio *bio)
- {
- return dm_per_bio_data(bio, multipath_per_bio_data_size());
- }
- static struct dm_bio_details *get_bio_details_from_mpio(struct dm_mpath_io *mpio)
- {
- /* dm_bio_details is immediately after the dm_mpath_io in bio's per-bio-data */
- void *bio_details = mpio + 1;
- return bio_details;
- }
- static void multipath_init_per_bio_data(struct bio *bio, struct dm_mpath_io **mpio_p)
- {
- struct dm_mpath_io *mpio = get_mpio_from_bio(bio);
- struct dm_bio_details *bio_details = get_bio_details_from_mpio(mpio);
- mpio->nr_bytes = bio->bi_iter.bi_size;
- mpio->pgpath = NULL;
- mpio->start_time_ns = 0;
- *mpio_p = mpio;
- dm_bio_record(bio_details, bio);
- }
- /*-----------------------------------------------
- * Path selection
- *-----------------------------------------------*/
- static int __pg_init_all_paths(struct multipath *m)
- {
- struct pgpath *pgpath;
- unsigned long pg_init_delay = 0;
- lockdep_assert_held(&m->lock);
- if (atomic_read(&m->pg_init_in_progress) || test_bit(MPATHF_PG_INIT_DISABLED, &m->flags))
- return 0;
- atomic_inc(&m->pg_init_count);
- clear_bit(MPATHF_PG_INIT_REQUIRED, &m->flags);
- /* Check here to reset pg_init_required */
- if (!m->current_pg)
- return 0;
- if (test_bit(MPATHF_PG_INIT_DELAY_RETRY, &m->flags))
- pg_init_delay = msecs_to_jiffies(m->pg_init_delay_msecs != DM_PG_INIT_DELAY_DEFAULT ?
- m->pg_init_delay_msecs : DM_PG_INIT_DELAY_MSECS);
- list_for_each_entry(pgpath, &m->current_pg->pgpaths, list) {
- /* Skip failed paths */
- if (!pgpath->is_active)
- continue;
- if (queue_delayed_work(kmpath_handlerd, &pgpath->activate_path,
- pg_init_delay))
- atomic_inc(&m->pg_init_in_progress);
- }
- return atomic_read(&m->pg_init_in_progress);
- }
- static int pg_init_all_paths(struct multipath *m)
- {
- int ret;
- unsigned long flags;
- spin_lock_irqsave(&m->lock, flags);
- ret = __pg_init_all_paths(m);
- spin_unlock_irqrestore(&m->lock, flags);
- return ret;
- }
- static void __switch_pg(struct multipath *m, struct priority_group *pg)
- {
- lockdep_assert_held(&m->lock);
- m->current_pg = pg;
- /* Must we initialise the PG first, and queue I/O till it's ready? */
- if (m->hw_handler_name) {
- set_bit(MPATHF_PG_INIT_REQUIRED, &m->flags);
- set_bit(MPATHF_QUEUE_IO, &m->flags);
- } else {
- clear_bit(MPATHF_PG_INIT_REQUIRED, &m->flags);
- clear_bit(MPATHF_QUEUE_IO, &m->flags);
- }
- atomic_set(&m->pg_init_count, 0);
- }
- static struct pgpath *choose_path_in_pg(struct multipath *m,
- struct priority_group *pg,
- size_t nr_bytes)
- {
- unsigned long flags;
- struct dm_path *path;
- struct pgpath *pgpath;
- path = pg->ps.type->select_path(&pg->ps, nr_bytes);
- if (!path)
- return ERR_PTR(-ENXIO);
- pgpath = path_to_pgpath(path);
- if (unlikely(READ_ONCE(m->current_pg) != pg)) {
- /* Only update current_pgpath if pg changed */
- spin_lock_irqsave(&m->lock, flags);
- m->current_pgpath = pgpath;
- __switch_pg(m, pg);
- spin_unlock_irqrestore(&m->lock, flags);
- }
- return pgpath;
- }
- static struct pgpath *choose_pgpath(struct multipath *m, size_t nr_bytes)
- {
- unsigned long flags;
- struct priority_group *pg;
- struct pgpath *pgpath;
- unsigned int bypassed = 1;
- if (!atomic_read(&m->nr_valid_paths)) {
- spin_lock_irqsave(&m->lock, flags);
- clear_bit(MPATHF_QUEUE_IO, &m->flags);
- spin_unlock_irqrestore(&m->lock, flags);
- goto failed;
- }
- /* 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;
- }
- m->next_pg = NULL;
- spin_unlock_irqrestore(&m->lock, flags);
- pgpath = choose_path_in_pg(m, pg, 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;
- }
- /*
- * Loop through priority groups until we find a valid path.
- * First time we skip PGs marked 'bypassed'.
- * Second time we only try the ones we skipped, but set
- * pg_init_delay_retry so we do not hammer controllers.
- */
- do {
- list_for_each_entry(pg, &m->priority_groups, list) {
- if (pg->bypassed == !!bypassed)
- continue;
- pgpath = choose_path_in_pg(m, pg, nr_bytes);
- if (!IS_ERR_OR_NULL(pgpath)) {
- if (!bypassed) {
- spin_lock_irqsave(&m->lock, flags);
- set_bit(MPATHF_PG_INIT_DELAY_RETRY, &m->flags);
- spin_unlock_irqrestore(&m->lock, flags);
- }
- return pgpath;
- }
- }
- } while (bypassed--);
- failed:
- spin_lock_irqsave(&m->lock, flags);
- m->current_pgpath = NULL;
- m->current_pg = NULL;
- spin_unlock_irqrestore(&m->lock, flags);
- return NULL;
- }
- /*
- * dm_report_EIO() is a macro instead of a function to make pr_debug_ratelimited()
- * report the function name and line number of the function from which
- * it has been invoked.
- */
- #define dm_report_EIO(m) \
- do { \
- DMDEBUG_LIMIT("%s: returning EIO; QIFNP = %d; SQIFNP = %d; DNFS = %d", \
- dm_table_device_name((m)->ti->table), \
- test_bit(MPATHF_QUEUE_IF_NO_PATH, &(m)->flags), \
- test_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &(m)->flags), \
- dm_noflush_suspending((m)->ti)); \
- } while (0)
- /*
- * Check whether bios must be queued in the device-mapper core rather
- * than here in the target.
- */
- static bool __must_push_back(struct multipath *m)
- {
- return dm_noflush_suspending(m->ti);
- }
- static bool must_push_back_rq(struct multipath *m)
- {
- unsigned long flags;
- bool ret;
- spin_lock_irqsave(&m->lock, flags);
- ret = (test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags) || __must_push_back(m));
- spin_unlock_irqrestore(&m->lock, flags);
- return ret;
- }
- /*
- * Map cloned requests (request-based multipath)
- */
- static int multipath_clone_and_map(struct dm_target *ti, struct request *rq,
- union map_info *map_context,
- struct request **__clone)
- {
- struct multipath *m = ti->private;
- size_t nr_bytes = blk_rq_bytes(rq);
- struct pgpath *pgpath;
- struct block_device *bdev;
- struct dm_mpath_io *mpio = get_mpio(map_context);
- struct request_queue *q;
- struct request *clone;
- /* Do we need to select a new pgpath? */
- pgpath = READ_ONCE(m->current_pgpath);
- if (!pgpath || !mpath_double_check_test_bit(MPATHF_QUEUE_IO, m))
- pgpath = choose_pgpath(m, nr_bytes);
- if (!pgpath) {
- if (must_push_back_rq(m))
- return DM_MAPIO_DELAY_REQUEUE;
- dm_report_EIO(m); /* Failed */
- return DM_MAPIO_KILL;
- } else if (mpath_double_check_test_bit(MPATHF_QUEUE_IO, m) ||
- mpath_double_check_test_bit(MPATHF_PG_INIT_REQUIRED, m)) {
- pg_init_all_paths(m);
- return DM_MAPIO_DELAY_REQUEUE;
- }
- mpio->pgpath = pgpath;
- mpio->nr_bytes = nr_bytes;
- bdev = pgpath->path.dev->bdev;
- q = bdev_get_queue(bdev);
- clone = blk_mq_alloc_request(q, rq->cmd_flags | REQ_NOMERGE,
- BLK_MQ_REQ_NOWAIT);
- if (IS_ERR(clone)) {
- /* EBUSY, ENODEV or EWOULDBLOCK: requeue */
- if (blk_queue_dying(q)) {
- atomic_inc(&m->pg_init_in_progress);
- activate_or_offline_path(pgpath);
- return DM_MAPIO_DELAY_REQUEUE;
- }
- /*
- * blk-mq's SCHED_RESTART can cover this requeue, so we
- * needn't deal with it by DELAY_REQUEUE. More importantly,
- * we have to return DM_MAPIO_REQUEUE so that blk-mq can
- * get the queue busy feedback (via BLK_STS_RESOURCE),
- * otherwise I/O merging can suffer.
- */
- return DM_MAPIO_REQUEUE;
- }
- clone->bio = clone->biotail = NULL;
- clone->cmd_flags |= REQ_FAILFAST_TRANSPORT;
- *__clone = clone;
- if (pgpath->pg->ps.type->start_io)
- pgpath->pg->ps.type->start_io(&pgpath->pg->ps,
- &pgpath->path,
- nr_bytes);
- return DM_MAPIO_REMAPPED;
- }
- static void multipath_release_clone(struct request *clone,
- union map_info *map_context)
- {
- if (unlikely(map_context)) {
- /*
- * non-NULL map_context means caller is still map
- * method; must undo multipath_clone_and_map()
- */
- struct dm_mpath_io *mpio = get_mpio(map_context);
- struct pgpath *pgpath = mpio->pgpath;
- if (pgpath && pgpath->pg->ps.type->end_io)
- pgpath->pg->ps.type->end_io(&pgpath->pg->ps,
- &pgpath->path,
- mpio->nr_bytes,
- clone->io_start_time_ns);
- }
- blk_mq_free_request(clone);
- }
- /*
- * Map cloned bios (bio-based multipath)
- */
- static void __multipath_queue_bio(struct multipath *m, struct bio *bio)
- {
- /* Queue for the daemon to resubmit */
- bio_list_add(&m->queued_bios, bio);
- if (!test_bit(MPATHF_QUEUE_IO, &m->flags))
- queue_work(kmultipathd, &m->process_queued_bios);
- }
- static void multipath_queue_bio(struct multipath *m, struct bio *bio)
- {
- unsigned long flags;
- spin_lock_irqsave(&m->lock, flags);
- __multipath_queue_bio(m, bio);
- spin_unlock_irqrestore(&m->lock, flags);
- }
- static struct pgpath *__map_bio(struct multipath *m, struct bio *bio)
- {
- struct pgpath *pgpath;
- unsigned long flags;
- /* Do we need to select a new pgpath? */
- pgpath = READ_ONCE(m->current_pgpath);
- if (!pgpath || !mpath_double_check_test_bit(MPATHF_QUEUE_IO, m))
- pgpath = choose_pgpath(m, bio->bi_iter.bi_size);
- if (!pgpath) {
- spin_lock_irqsave(&m->lock, flags);
- if (test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) {
- __multipath_queue_bio(m, bio);
- pgpath = ERR_PTR(-EAGAIN);
- }
- spin_unlock_irqrestore(&m->lock, flags);
- } else if (mpath_double_check_test_bit(MPATHF_QUEUE_IO, m) ||
- mpath_double_check_test_bit(MPATHF_PG_INIT_REQUIRED, m)) {
- multipath_queue_bio(m, bio);
- pg_init_all_paths(m);
- return ERR_PTR(-EAGAIN);
- }
- return pgpath;
- }
- static int __multipath_map_bio(struct multipath *m, struct bio *bio,
- struct dm_mpath_io *mpio)
- {
- struct pgpath *pgpath = __map_bio(m, bio);
- if (IS_ERR(pgpath))
- return DM_MAPIO_SUBMITTED;
- if (!pgpath) {
- if (__must_push_back(m))
- return DM_MAPIO_REQUEUE;
- dm_report_EIO(m);
- return DM_MAPIO_KILL;
- }
- mpio->pgpath = pgpath;
- if (dm_ps_use_hr_timer(pgpath->pg->ps.type))
- mpio->start_time_ns = ktime_get_ns();
- bio->bi_status = 0;
- bio_set_dev(bio, pgpath->path.dev->bdev);
- bio->bi_opf |= REQ_FAILFAST_TRANSPORT;
- if (pgpath->pg->ps.type->start_io)
- pgpath->pg->ps.type->start_io(&pgpath->pg->ps,
- &pgpath->path,
- mpio->nr_bytes);
- return DM_MAPIO_REMAPPED;
- }
- static int multipath_map_bio(struct dm_target *ti, struct bio *bio)
- {
- struct multipath *m = ti->private;
- struct dm_mpath_io *mpio = NULL;
- multipath_init_per_bio_data(bio, &mpio);
- return __multipath_map_bio(m, bio, mpio);
- }
- static void process_queued_io_list(struct multipath *m)
- {
- if (m->queue_mode == DM_TYPE_REQUEST_BASED)
- dm_mq_kick_requeue_list(dm_table_get_md(m->ti->table));
- else if (m->queue_mode == DM_TYPE_BIO_BASED)
- queue_work(kmultipathd, &m->process_queued_bios);
- }
- static void process_queued_bios(struct work_struct *work)
- {
- int r;
- unsigned long flags;
- struct bio *bio;
- struct bio_list bios;
- struct blk_plug plug;
- struct multipath *m =
- container_of(work, struct multipath, process_queued_bios);
- bio_list_init(&bios);
- spin_lock_irqsave(&m->lock, flags);
- if (bio_list_empty(&m->queued_bios)) {
- spin_unlock_irqrestore(&m->lock, flags);
- return;
- }
- bio_list_merge(&bios, &m->queued_bios);
- bio_list_init(&m->queued_bios);
- spin_unlock_irqrestore(&m->lock, flags);
- blk_start_plug(&plug);
- while ((bio = bio_list_pop(&bios))) {
- struct dm_mpath_io *mpio = get_mpio_from_bio(bio);
- dm_bio_restore(get_bio_details_from_mpio(mpio), bio);
- r = __multipath_map_bio(m, bio, mpio);
- switch (r) {
- case DM_MAPIO_KILL:
- bio->bi_status = BLK_STS_IOERR;
- bio_endio(bio);
- break;
- case DM_MAPIO_REQUEUE:
- bio->bi_status = BLK_STS_DM_REQUEUE;
- bio_endio(bio);
- break;
- case DM_MAPIO_REMAPPED:
- submit_bio_noacct(bio);
- break;
- case DM_MAPIO_SUBMITTED:
- break;
- default:
- WARN_ONCE(true, "__multipath_map_bio() returned %d\n", r);
- }
- }
- blk_finish_plug(&plug);
- }
- /*
- * 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, const char *caller)
- {
- unsigned long flags;
- bool queue_if_no_path_bit, saved_queue_if_no_path_bit;
- const char *dm_dev_name = dm_table_device_name(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);
- queue_if_no_path_bit = test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags);
- saved_queue_if_no_path_bit = test_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &m->flags);
- 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_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) {
- /* due to "fail_if_no_path" message, need to honor it. */
- clear_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &m->flags);
- }
- 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) {
- dm_table_run_md_queue_async(m->ti->table);
- process_queued_io_list(m);
- }
- return 0;
- }
- /*
- * If the queue_if_no_path timeout fires, turn off queue_if_no_path and
- * process any queued I/O.
- */
- static void queue_if_no_path_timeout_work(struct timer_list *t)
- {
- struct multipath *m = from_timer(m, t, nopath_timer);
- DMWARN("queue_if_no_path timeout on %s, failing queued IO",
- dm_table_device_name(m->ti->table));
- queue_if_no_path(m, false, false, __func__);
- }
- /*
- * Enable the queue_if_no_path timeout if necessary.
- * Called with m->lock held.
- */
- static void enable_nopath_timeout(struct multipath *m)
- {
- unsigned long queue_if_no_path_timeout =
- READ_ONCE(queue_if_no_path_timeout_secs) * HZ;
- lockdep_assert_held(&m->lock);
- if (queue_if_no_path_timeout > 0 &&
- atomic_read(&m->nr_valid_paths) == 0 &&
- test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) {
- mod_timer(&m->nopath_timer,
- jiffies + queue_if_no_path_timeout);
- }
- }
- static void disable_nopath_timeout(struct multipath *m)
- {
- del_timer_sync(&m->nopath_timer);
- }
- /*
- * An event is triggered whenever a path is taken out of use.
- * Includes path failure and PG bypass.
- */
- static void trigger_event(struct work_struct *work)
- {
- struct multipath *m =
- container_of(work, struct multipath, trigger_event);
- dm_table_event(m->ti->table);
- }
- /*-----------------------------------------------------------------
- * Constructor/argument parsing:
- * <#multipath feature args> [<arg>]*
- * <#hw_handler args> [hw_handler [<arg>]*]
- * <#priority groups>
- * <initial priority group>
- * [<selector> <#selector args> [<arg>]*
- * <#paths> <#per-path selector args>
- * [<path> [<arg>]* ]+ ]+
- *---------------------------------------------------------------*/
- static int parse_path_selector(struct dm_arg_set *as, struct priority_group *pg,
- struct dm_target *ti)
- {
- int r;
- struct path_selector_type *pst;
- unsigned int ps_argc;
- static const struct dm_arg _args[] = {
- {0, 1024, "invalid number of path selector args"},
- };
- pst = dm_get_path_selector(dm_shift_arg(as));
- if (!pst) {
- ti->error = "unknown path selector type";
- return -EINVAL;
- }
- r = dm_read_arg_group(_args, as, &ps_argc, &ti->error);
- if (r) {
- dm_put_path_selector(pst);
- return -EINVAL;
- }
- r = pst->create(&pg->ps, ps_argc, as->argv);
- if (r) {
- dm_put_path_selector(pst);
- ti->error = "path selector constructor failed";
- return r;
- }
- pg->ps.type = pst;
- dm_consume_args(as, ps_argc);
- return 0;
- }
- static int setup_scsi_dh(struct block_device *bdev, struct multipath *m,
- const char **attached_handler_name, char **error)
- {
- struct request_queue *q = bdev_get_queue(bdev);
- int r;
- if (mpath_double_check_test_bit(MPATHF_RETAIN_ATTACHED_HW_HANDLER, m)) {
- retain:
- if (*attached_handler_name) {
- /*
- * Clear any hw_handler_params associated with a
- * handler that isn't already attached.
- */
- if (m->hw_handler_name && strcmp(*attached_handler_name, m->hw_handler_name)) {
- kfree(m->hw_handler_params);
- m->hw_handler_params = NULL;
- }
- /*
- * Reset hw_handler_name to match the attached handler
- *
- * NB. This modifies the table line to show the actual
- * handler instead of the original table passed in.
- */
- kfree(m->hw_handler_name);
- m->hw_handler_name = *attached_handler_name;
- *attached_handler_name = NULL;
- }
- }
- if (m->hw_handler_name) {
- r = scsi_dh_attach(q, m->hw_handler_name);
- if (r == -EBUSY) {
- DMINFO("retaining handler on device %pg", bdev);
- goto retain;
- }
- if (r < 0) {
- *error = "error attaching hardware handler";
- return r;
- }
- if (m->hw_handler_params) {
- r = scsi_dh_set_params(q, m->hw_handler_params);
- if (r < 0) {
- *error = "unable to set hardware handler parameters";
- return r;
- }
- }
- }
- return 0;
- }
- static struct pgpath *parse_path(struct dm_arg_set *as, struct path_selector *ps,
- struct dm_target *ti)
- {
- int r;
- struct pgpath *p;
- struct multipath *m = ti->private;
- struct request_queue *q;
- const char *attached_handler_name = NULL;
- /* we need at least a path arg */
- if (as->argc < 1) {
- ti->error = "no device given";
- return ERR_PTR(-EINVAL);
- }
- p = alloc_pgpath();
- if (!p)
- return ERR_PTR(-ENOMEM);
- r = dm_get_device(ti, dm_shift_arg(as), dm_table_get_mode(ti->table),
- &p->path.dev);
- if (r) {
- ti->error = "error getting device";
- goto bad;
- }
- q = bdev_get_queue(p->path.dev->bdev);
- attached_handler_name = scsi_dh_attached_handler_name(q, GFP_KERNEL);
- if (attached_handler_name || m->hw_handler_name) {
- INIT_DELAYED_WORK(&p->activate_path, activate_path_work);
- r = setup_scsi_dh(p->path.dev->bdev, m, &attached_handler_name, &ti->error);
- kfree(attached_handler_name);
- if (r) {
- dm_put_device(ti, p->path.dev);
- goto bad;
- }
- }
- r = ps->type->add_path(ps, &p->path, as->argc, as->argv, &ti->error);
- if (r) {
- dm_put_device(ti, p->path.dev);
- goto bad;
- }
- return p;
- bad:
- free_pgpath(p);
- return ERR_PTR(r);
- }
- static struct priority_group *parse_priority_group(struct dm_arg_set *as,
- struct multipath *m)
- {
- static const struct dm_arg _args[] = {
- {1, 1024, "invalid number of paths"},
- {0, 1024, "invalid number of selector args"}
- };
- int r;
- unsigned int i, nr_selector_args, nr_args;
- struct priority_group *pg;
- struct dm_target *ti = m->ti;
- if (as->argc < 2) {
- as->argc = 0;
- ti->error = "not enough priority group arguments";
- return ERR_PTR(-EINVAL);
- }
- pg = alloc_priority_group();
- if (!pg) {
- ti->error = "couldn't allocate priority group";
- return ERR_PTR(-ENOMEM);
- }
- pg->m = m;
- r = parse_path_selector(as, pg, ti);
- if (r)
- goto bad;
- /*
- * read the paths
- */
- r = dm_read_arg(_args, as, &pg->nr_pgpaths, &ti->error);
- if (r)
- goto bad;
- r = dm_read_arg(_args + 1, as, &nr_selector_args, &ti->error);
- if (r)
- goto bad;
- nr_args = 1 + nr_selector_args;
- for (i = 0; i < pg->nr_pgpaths; i++) {
- struct pgpath *pgpath;
- struct dm_arg_set path_args;
- if (as->argc < nr_args) {
- ti->error = "not enough path parameters";
- r = -EINVAL;
- goto bad;
- }
- path_args.argc = nr_args;
- path_args.argv = as->argv;
- pgpath = parse_path(&path_args, &pg->ps, ti);
- if (IS_ERR(pgpath)) {
- r = PTR_ERR(pgpath);
- goto bad;
- }
- pgpath->pg = pg;
- list_add_tail(&pgpath->list, &pg->pgpaths);
- dm_consume_args(as, nr_args);
- }
- return pg;
- bad:
- free_priority_group(pg, ti);
- return ERR_PTR(r);
- }
- static int parse_hw_handler(struct dm_arg_set *as, struct multipath *m)
- {
- unsigned int hw_argc;
- int ret;
- struct dm_target *ti = m->ti;
- static const struct dm_arg _args[] = {
- {0, 1024, "invalid number of hardware handler args"},
- };
- if (dm_read_arg_group(_args, as, &hw_argc, &ti->error))
- return -EINVAL;
- if (!hw_argc)
- return 0;
- if (m->queue_mode == DM_TYPE_BIO_BASED) {
- dm_consume_args(as, hw_argc);
- DMERR("bio-based multipath doesn't allow hardware handler args");
- return 0;
- }
- m->hw_handler_name = kstrdup(dm_shift_arg(as), GFP_KERNEL);
- if (!m->hw_handler_name)
- return -EINVAL;
- if (hw_argc > 1) {
- char *p;
- int i, j, len = 4;
- for (i = 0; i <= hw_argc - 2; i++)
- len += strlen(as->argv[i]) + 1;
- p = m->hw_handler_params = kzalloc(len, GFP_KERNEL);
- if (!p) {
- ti->error = "memory allocation failed";
- ret = -ENOMEM;
- goto fail;
- }
- j = sprintf(p, "%d", hw_argc - 1);
- for (i = 0, p += j + 1; i <= hw_argc - 2; i++, p += j + 1)
- j = sprintf(p, "%s", as->argv[i]);
- }
- dm_consume_args(as, hw_argc - 1);
- return 0;
- fail:
- kfree(m->hw_handler_name);
- m->hw_handler_name = NULL;
- return ret;
- }
- static int parse_features(struct dm_arg_set *as, struct multipath *m)
- {
- int r;
- unsigned int argc;
- struct dm_target *ti = m->ti;
- const char *arg_name;
- static const struct dm_arg _args[] = {
- {0, 8, "invalid number of feature args"},
- {1, 50, "pg_init_retries must be between 1 and 50"},
- {0, 60000, "pg_init_delay_msecs must be between 0 and 60000"},
- };
- r = dm_read_arg_group(_args, as, &argc, &ti->error);
- if (r)
- return -EINVAL;
- if (!argc)
- return 0;
- do {
- arg_name = dm_shift_arg(as);
- argc--;
- if (!strcasecmp(arg_name, "queue_if_no_path")) {
- r = queue_if_no_path(m, true, false, __func__);
- continue;
- }
- if (!strcasecmp(arg_name, "retain_attached_hw_handler")) {
- set_bit(MPATHF_RETAIN_ATTACHED_HW_HANDLER, &m->flags);
- continue;
- }
- if (!strcasecmp(arg_name, "pg_init_retries") &&
- (argc >= 1)) {
- r = dm_read_arg(_args + 1, as, &m->pg_init_retries, &ti->error);
- argc--;
- continue;
- }
- if (!strcasecmp(arg_name, "pg_init_delay_msecs") &&
- (argc >= 1)) {
- r = dm_read_arg(_args + 2, as, &m->pg_init_delay_msecs, &ti->error);
- argc--;
- continue;
- }
- if (!strcasecmp(arg_name, "queue_mode") &&
- (argc >= 1)) {
- const char *queue_mode_name = dm_shift_arg(as);
- if (!strcasecmp(queue_mode_name, "bio"))
- m->queue_mode = DM_TYPE_BIO_BASED;
- else if (!strcasecmp(queue_mode_name, "rq") ||
- !strcasecmp(queue_mode_name, "mq"))
- m->queue_mode = DM_TYPE_REQUEST_BASED;
- else {
- ti->error = "Unknown 'queue_mode' requested";
- r = -EINVAL;
- }
- argc--;
- continue;
- }
- ti->error = "Unrecognised multipath feature request";
- r = -EINVAL;
- } while (argc && !r);
- return r;
- }
- static int multipath_ctr(struct dm_target *ti, unsigned int argc, char **argv)
- {
- /* target arguments */
- static const struct dm_arg _args[] = {
- {0, 1024, "invalid number of priority groups"},
- {0, 1024, "invalid initial priority group number"},
- };
- int r;
- struct multipath *m;
- struct dm_arg_set as;
- unsigned int pg_count = 0;
- unsigned int next_pg_num;
- unsigned long flags;
- as.argc = argc;
- as.argv = argv;
- m = alloc_multipath(ti);
- if (!m) {
- ti->error = "can't allocate multipath";
- return -EINVAL;
- }
- r = parse_features(&as, m);
- if (r)
- goto bad;
- r = alloc_multipath_stage2(ti, m);
- if (r)
- goto bad;
- r = parse_hw_handler(&as, m);
- if (r)
- goto bad;
- r = dm_read_arg(_args, &as, &m->nr_priority_groups, &ti->error);
- if (r)
- goto bad;
- r = dm_read_arg(_args + 1, &as, &next_pg_num, &ti->error);
- if (r)
- goto bad;
- if ((!m->nr_priority_groups && next_pg_num) ||
- (m->nr_priority_groups && !next_pg_num)) {
- ti->error = "invalid initial priority group";
- r = -EINVAL;
- goto bad;
- }
- /* parse the priority groups */
- while (as.argc) {
- struct priority_group *pg;
- unsigned int nr_valid_paths = atomic_read(&m->nr_valid_paths);
- pg = parse_priority_group(&as, m);
- if (IS_ERR(pg)) {
- r = PTR_ERR(pg);
- goto bad;
- }
- nr_valid_paths += pg->nr_pgpaths;
- atomic_set(&m->nr_valid_paths, nr_valid_paths);
- list_add_tail(&pg->list, &m->priority_groups);
- pg_count++;
- pg->pg_num = pg_count;
- if (!--next_pg_num)
- m->next_pg = pg;
- }
- if (pg_count != m->nr_priority_groups) {
- ti->error = "priority group count mismatch";
- r = -EINVAL;
- goto bad;
- }
- spin_lock_irqsave(&m->lock, flags);
- enable_nopath_timeout(m);
- spin_unlock_irqrestore(&m->lock, flags);
- ti->num_flush_bios = 1;
- ti->num_discard_bios = 1;
- ti->num_write_zeroes_bios = 1;
- if (m->queue_mode == DM_TYPE_BIO_BASED)
- ti->per_io_data_size = multipath_per_bio_data_size();
- else
- ti->per_io_data_size = sizeof(struct dm_mpath_io);
- return 0;
- bad:
- free_multipath(m);
- return r;
- }
- static void multipath_wait_for_pg_init_completion(struct multipath *m)
- {
- DEFINE_WAIT(wait);
- while (1) {
- prepare_to_wait(&m->pg_init_wait, &wait, TASK_UNINTERRUPTIBLE);
- if (!atomic_read(&m->pg_init_in_progress))
- break;
- io_schedule();
- }
- finish_wait(&m->pg_init_wait, &wait);
- }
- static void flush_multipath_work(struct multipath *m)
- {
- if (m->hw_handler_name) {
- unsigned long flags;
- if (!atomic_read(&m->pg_init_in_progress))
- goto skip;
- spin_lock_irqsave(&m->lock, flags);
- if (atomic_read(&m->pg_init_in_progress) &&
- !test_and_set_bit(MPATHF_PG_INIT_DISABLED, &m->flags)) {
- spin_unlock_irqrestore(&m->lock, flags);
- flush_workqueue(kmpath_handlerd);
- multipath_wait_for_pg_init_completion(m);
- spin_lock_irqsave(&m->lock, flags);
- clear_bit(MPATHF_PG_INIT_DISABLED, &m->flags);
- }
- spin_unlock_irqrestore(&m->lock, flags);
- }
- skip:
- if (m->queue_mode == DM_TYPE_BIO_BASED)
- flush_work(&m->process_queued_bios);
- flush_work(&m->trigger_event);
- }
- static void multipath_dtr(struct dm_target *ti)
- {
- struct multipath *m = ti->private;
- disable_nopath_timeout(m);
- flush_multipath_work(m);
- free_multipath(m);
- }
- /*
- * Take a path out of use.
- */
- static int fail_path(struct pgpath *pgpath)
- {
- unsigned long flags;
- struct multipath *m = pgpath->pg->m;
- spin_lock_irqsave(&m->lock, flags);
- if (!pgpath->is_active)
- goto out;
- DMWARN("%s: Failing path %s.",
- dm_table_device_name(m->ti->table),
- pgpath->path.dev->name);
- pgpath->pg->ps.type->fail_path(&pgpath->pg->ps, &pgpath->path);
- pgpath->is_active = false;
- pgpath->fail_count++;
- atomic_dec(&m->nr_valid_paths);
- if (pgpath == m->current_pgpath)
- m->current_pgpath = NULL;
- dm_path_uevent(DM_UEVENT_PATH_FAILED, m->ti,
- pgpath->path.dev->name, atomic_read(&m->nr_valid_paths));
- schedule_work(&m->trigger_event);
- enable_nopath_timeout(m);
- out:
- spin_unlock_irqrestore(&m->lock, flags);
- return 0;
- }
- /*
- * Reinstate a previously-failed path
- */
- static int reinstate_path(struct pgpath *pgpath)
- {
- int r = 0, run_queue = 0;
- unsigned long flags;
- struct multipath *m = pgpath->pg->m;
- unsigned int nr_valid_paths;
- spin_lock_irqsave(&m->lock, flags);
- if (pgpath->is_active)
- goto out;
- DMWARN("%s: Reinstating path %s.",
- dm_table_device_name(m->ti->table),
- pgpath->path.dev->name);
- r = pgpath->pg->ps.type->reinstate_path(&pgpath->pg->ps, &pgpath->path);
- if (r)
- goto out;
- pgpath->is_active = true;
- nr_valid_paths = atomic_inc_return(&m->nr_valid_paths);
- if (nr_valid_paths == 1) {
- m->current_pgpath = NULL;
- run_queue = 1;
- } else if (m->hw_handler_name && (m->current_pg == pgpath->pg)) {
- if (queue_work(kmpath_handlerd, &pgpath->activate_path.work))
- atomic_inc(&m->pg_init_in_progress);
- }
- dm_path_uevent(DM_UEVENT_PATH_REINSTATED, m->ti,
- pgpath->path.dev->name, nr_valid_paths);
- schedule_work(&m->trigger_event);
- out:
- spin_unlock_irqrestore(&m->lock, flags);
- if (run_queue) {
- dm_table_run_md_queue_async(m->ti->table);
- process_queued_io_list(m);
- }
- if (pgpath->is_active)
- disable_nopath_timeout(m);
- return r;
- }
- /*
- * Fail or reinstate all paths that match the provided struct dm_dev.
- */
- static int action_dev(struct multipath *m, struct dm_dev *dev,
- action_fn action)
- {
- int r = -EINVAL;
- struct pgpath *pgpath;
- struct priority_group *pg;
- list_for_each_entry(pg, &m->priority_groups, list) {
- list_for_each_entry(pgpath, &pg->pgpaths, list) {
- if (pgpath->path.dev == dev)
- r = action(pgpath);
- }
- }
- return r;
- }
- /*
- * Temporarily try to avoid having to use the specified PG
- */
- static void bypass_pg(struct multipath *m, struct priority_group *pg,
- bool bypassed)
- {
- unsigned long flags;
- spin_lock_irqsave(&m->lock, flags);
- pg->bypassed = bypassed;
- m->current_pgpath = NULL;
- m->current_pg = NULL;
- spin_unlock_irqrestore(&m->lock, flags);
- schedule_work(&m->trigger_event);
- }
- /*
- * Switch to using the specified PG from the next I/O that gets mapped
- */
- static int switch_pg_num(struct multipath *m, const char *pgstr)
- {
- struct priority_group *pg;
- unsigned int pgnum;
- unsigned long flags;
- char dummy;
- if (!pgstr || (sscanf(pgstr, "%u%c", &pgnum, &dummy) != 1) || !pgnum ||
- !m->nr_priority_groups || (pgnum > m->nr_priority_groups)) {
- DMWARN("invalid PG number supplied to switch_pg_num");
- return -EINVAL;
- }
- spin_lock_irqsave(&m->lock, flags);
- list_for_each_entry(pg, &m->priority_groups, list) {
- pg->bypassed = false;
- if (--pgnum)
- continue;
- m->current_pgpath = NULL;
- m->current_pg = NULL;
- m->next_pg = pg;
- }
- spin_unlock_irqrestore(&m->lock, flags);
- schedule_work(&m->trigger_event);
- return 0;
- }
- /*
- * Set/clear bypassed status of a PG.
- * PGs are numbered upwards from 1 in the order they were declared.
- */
- static int bypass_pg_num(struct multipath *m, const char *pgstr, bool bypassed)
- {
- struct priority_group *pg;
- unsigned int pgnum;
- char dummy;
- if (!pgstr || (sscanf(pgstr, "%u%c", &pgnum, &dummy) != 1) || !pgnum ||
- !m->nr_priority_groups || (pgnum > m->nr_priority_groups)) {
- DMWARN("invalid PG number supplied to bypass_pg");
- return -EINVAL;
- }
- list_for_each_entry(pg, &m->priority_groups, list) {
- if (!--pgnum)
- break;
- }
- bypass_pg(m, pg, bypassed);
- return 0;
- }
- /*
- * Should we retry pg_init immediately?
- */
- static bool pg_init_limit_reached(struct multipath *m, struct pgpath *pgpath)
- {
- unsigned long flags;
- bool limit_reached = false;
- spin_lock_irqsave(&m->lock, flags);
- if (atomic_read(&m->pg_init_count) <= m->pg_init_retries &&
- !test_bit(MPATHF_PG_INIT_DISABLED, &m->flags))
- set_bit(MPATHF_PG_INIT_REQUIRED, &m->flags);
- else
- limit_reached = true;
- spin_unlock_irqrestore(&m->lock, flags);
- return limit_reached;
- }
- static void pg_init_done(void *data, int errors)
- {
- struct pgpath *pgpath = data;
- struct priority_group *pg = pgpath->pg;
- struct multipath *m = pg->m;
- unsigned long flags;
- bool delay_retry = false;
- /* device or driver problems */
- switch (errors) {
- case SCSI_DH_OK:
- break;
- case SCSI_DH_NOSYS:
- if (!m->hw_handler_name) {
- errors = 0;
- break;
- }
- DMERR("Could not failover the device: Handler scsi_dh_%s "
- "Error %d.", m->hw_handler_name, errors);
- /*
- * Fail path for now, so we do not ping pong
- */
- fail_path(pgpath);
- break;
- case SCSI_DH_DEV_TEMP_BUSY:
- /*
- * Probably doing something like FW upgrade on the
- * controller so try the other pg.
- */
- bypass_pg(m, pg, true);
- break;
- case SCSI_DH_RETRY:
- /* Wait before retrying. */
- delay_retry = true;
- fallthrough;
- case SCSI_DH_IMM_RETRY:
- case SCSI_DH_RES_TEMP_UNAVAIL:
- if (pg_init_limit_reached(m, pgpath))
- fail_path(pgpath);
- errors = 0;
- break;
- case SCSI_DH_DEV_OFFLINED:
- default:
- /*
- * We probably do not want to fail the path for a device
- * error, but this is what the old dm did. In future
- * patches we can do more advanced handling.
- */
- fail_path(pgpath);
- }
- spin_lock_irqsave(&m->lock, flags);
- if (errors) {
- if (pgpath == m->current_pgpath) {
- DMERR("Could not failover device. Error %d.", errors);
- m->current_pgpath = NULL;
- m->current_pg = NULL;
- }
- } else if (!test_bit(MPATHF_PG_INIT_REQUIRED, &m->flags))
- pg->bypassed = false;
- if (atomic_dec_return(&m->pg_init_in_progress) > 0)
- /* Activations of other paths are still on going */
- goto out;
- if (test_bit(MPATHF_PG_INIT_REQUIRED, &m->flags)) {
- if (delay_retry)
- set_bit(MPATHF_PG_INIT_DELAY_RETRY, &m->flags);
- else
- clear_bit(MPATHF_PG_INIT_DELAY_RETRY, &m->flags);
- if (__pg_init_all_paths(m))
- goto out;
- }
- clear_bit(MPATHF_QUEUE_IO, &m->flags);
- process_queued_io_list(m);
- /*
- * Wake up any thread waiting to suspend.
- */
- wake_up(&m->pg_init_wait);
- out:
- spin_unlock_irqrestore(&m->lock, flags);
- }
- static void activate_or_offline_path(struct pgpath *pgpath)
- {
- struct request_queue *q = bdev_get_queue(pgpath->path.dev->bdev);
- if (pgpath->is_active && !blk_queue_dying(q))
- scsi_dh_activate(q, pg_init_done, pgpath);
- else
- pg_init_done(pgpath, SCSI_DH_DEV_OFFLINED);
- }
- static void activate_path_work(struct work_struct *work)
- {
- struct pgpath *pgpath =
- container_of(work, struct pgpath, activate_path.work);
- activate_or_offline_path(pgpath);
- }
- static int multipath_end_io(struct dm_target *ti, struct request *clone,
- blk_status_t error, union map_info *map_context)
- {
- struct dm_mpath_io *mpio = get_mpio(map_context);
- struct pgpath *pgpath = mpio->pgpath;
- int r = DM_ENDIO_DONE;
- /*
- * We don't queue any clone request inside the multipath target
- * during end I/O handling, since those clone requests don't have
- * bio clones. If we queue them inside the multipath target,
- * we need to make bio clones, that requires memory allocation.
- * (See drivers/md/dm-rq.c:end_clone_bio() about why the clone requests
- * don't have bio clones.)
- * Instead of queueing the clone request here, we queue the original
- * request into dm core, which will remake a clone request and
- * clone bios for it and resubmit it later.
- */
- if (error && blk_path_error(error)) {
- struct multipath *m = ti->private;
- if (error == BLK_STS_RESOURCE)
- r = DM_ENDIO_DELAY_REQUEUE;
- else
- r = DM_ENDIO_REQUEUE;
- if (pgpath)
- fail_path(pgpath);
- if (!atomic_read(&m->nr_valid_paths) &&
- !must_push_back_rq(m)) {
- if (error == BLK_STS_IOERR)
- dm_report_EIO(m);
- /* complete with the original error */
- r = DM_ENDIO_DONE;
- }
- }
- if (pgpath) {
- struct path_selector *ps = &pgpath->pg->ps;
- if (ps->type->end_io)
- ps->type->end_io(ps, &pgpath->path, mpio->nr_bytes,
- clone->io_start_time_ns);
- }
- return r;
- }
- static int multipath_end_io_bio(struct dm_target *ti, struct bio *clone,
- blk_status_t *error)
- {
- struct multipath *m = ti->private;
- struct dm_mpath_io *mpio = get_mpio_from_bio(clone);
- struct pgpath *pgpath = mpio->pgpath;
- unsigned long flags;
- int r = DM_ENDIO_DONE;
- if (!*error || !blk_path_error(*error))
- goto done;
- if (pgpath)
- fail_path(pgpath);
- if (!atomic_read(&m->nr_valid_paths)) {
- spin_lock_irqsave(&m->lock, flags);
- if (!test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) {
- if (__must_push_back(m)) {
- r = DM_ENDIO_REQUEUE;
- } else {
- dm_report_EIO(m);
- *error = BLK_STS_IOERR;
- }
- spin_unlock_irqrestore(&m->lock, flags);
- goto done;
- }
- spin_unlock_irqrestore(&m->lock, flags);
- }
- multipath_queue_bio(m, clone);
- r = DM_ENDIO_INCOMPLETE;
- done:
- if (pgpath) {
- struct path_selector *ps = &pgpath->pg->ps;
- if (ps->type->end_io)
- ps->type->end_io(ps, &pgpath->path, mpio->nr_bytes,
- (mpio->start_time_ns ?:
- dm_start_time_ns_from_clone(clone)));
- }
- return r;
- }
- /*
- * Suspend with flush can't complete until all the I/O is processed
- * so if the last path fails we must error any remaining I/O.
- * - Note that if the freeze_bdev fails while suspending, the
- * queue_if_no_path state is lost - userspace should reset it.
- * Otherwise, during noflush suspend, queue_if_no_path will not change.
- */
- static void multipath_presuspend(struct dm_target *ti)
- {
- struct multipath *m = ti->private;
- /* 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__);
- }
- static void multipath_postsuspend(struct dm_target *ti)
- {
- struct multipath *m = ti->private;
- mutex_lock(&m->work_mutex);
- flush_multipath_work(m);
- mutex_unlock(&m->work_mutex);
- }
- /*
- * Restore the queue_if_no_path setting.
- */
- static void multipath_resume(struct dm_target *ti)
- {
- struct multipath *m = ti->private;
- unsigned long flags;
- spin_lock_irqsave(&m->lock, flags);
- 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);
- }
- DMDEBUG("%s: %s finished; QIFNP = %d; SQIFNP = %d",
- dm_table_device_name(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);
- }
- /*
- * Info output has the following format:
- * num_multipath_feature_args [multipath_feature_args]*
- * num_handler_status_args [handler_status_args]*
- * num_groups init_group_number
- * [A|D|E num_ps_status_args [ps_status_args]*
- * num_paths num_selector_args
- * [path_dev A|F fail_count [selector_args]* ]+ ]+
- *
- * Table output has the following format (identical to the constructor string):
- * num_feature_args [features_args]*
- * num_handler_args hw_handler [hw_handler_args]*
- * num_groups init_group_number
- * [priority selector-name num_ps_args [ps_args]*
- * num_paths num_selector_args [path_dev [selector_args]* ]+ ]+
- */
- static void multipath_status(struct dm_target *ti, status_type_t type,
- unsigned int status_flags, char *result, unsigned int maxlen)
- {
- int sz = 0, pg_counter, pgpath_counter;
- unsigned long flags;
- struct multipath *m = ti->private;
- struct priority_group *pg;
- struct pgpath *p;
- unsigned int pg_num;
- char state;
- spin_lock_irqsave(&m->lock, flags);
- /* Features */
- if (type == STATUSTYPE_INFO)
- DMEMIT("2 %u %u ", test_bit(MPATHF_QUEUE_IO, &m->flags),
- atomic_read(&m->pg_init_count));
- else {
- DMEMIT("%u ", test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags) +
- (m->pg_init_retries > 0) * 2 +
- (m->pg_init_delay_msecs != DM_PG_INIT_DELAY_DEFAULT) * 2 +
- test_bit(MPATHF_RETAIN_ATTACHED_HW_HANDLER, &m->flags) +
- (m->queue_mode != DM_TYPE_REQUEST_BASED) * 2);
- if (test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags))
- DMEMIT("queue_if_no_path ");
- if (m->pg_init_retries)
- DMEMIT("pg_init_retries %u ", m->pg_init_retries);
- if (m->pg_init_delay_msecs != DM_PG_INIT_DELAY_DEFAULT)
- DMEMIT("pg_init_delay_msecs %u ", m->pg_init_delay_msecs);
- if (test_bit(MPATHF_RETAIN_ATTACHED_HW_HANDLER, &m->flags))
- DMEMIT("retain_attached_hw_handler ");
- if (m->queue_mode != DM_TYPE_REQUEST_BASED) {
- switch(m->queue_mode) {
- case DM_TYPE_BIO_BASED:
- DMEMIT("queue_mode bio ");
- break;
- default:
- WARN_ON_ONCE(true);
- break;
- }
- }
- }
- if (!m->hw_handler_name || type == STATUSTYPE_INFO)
- DMEMIT("0 ");
- else
- DMEMIT("1 %s ", m->hw_handler_name);
- DMEMIT("%u ", m->nr_priority_groups);
- if (m->next_pg)
- pg_num = m->next_pg->pg_num;
- else if (m->current_pg)
- pg_num = m->current_pg->pg_num;
- else
- pg_num = (m->nr_priority_groups ? 1 : 0);
- DMEMIT("%u ", pg_num);
- switch (type) {
- case STATUSTYPE_INFO:
- list_for_each_entry(pg, &m->priority_groups, list) {
- if (pg->bypassed)
- state = 'D'; /* Disabled */
- else if (pg == m->current_pg)
- state = 'A'; /* Currently Active */
- else
- state = 'E'; /* Enabled */
- DMEMIT("%c ", state);
- if (pg->ps.type->status)
- sz += pg->ps.type->status(&pg->ps, NULL, type,
- result + sz,
- maxlen - sz);
- else
- DMEMIT("0 ");
- DMEMIT("%u %u ", pg->nr_pgpaths,
- pg->ps.type->info_args);
- list_for_each_entry(p, &pg->pgpaths, list) {
- DMEMIT("%s %s %u ", p->path.dev->name,
- p->is_active ? "A" : "F",
- p->fail_count);
- if (pg->ps.type->status)
- sz += pg->ps.type->status(&pg->ps,
- &p->path, type, result + sz,
- maxlen - sz);
- }
- }
- break;
- case STATUSTYPE_TABLE:
- list_for_each_entry(pg, &m->priority_groups, list) {
- DMEMIT("%s ", pg->ps.type->name);
- if (pg->ps.type->status)
- sz += pg->ps.type->status(&pg->ps, NULL, type,
- result + sz,
- maxlen - sz);
- else
- DMEMIT("0 ");
- DMEMIT("%u %u ", pg->nr_pgpaths,
- pg->ps.type->table_args);
- list_for_each_entry(p, &pg->pgpaths, list) {
- DMEMIT("%s ", p->path.dev->name);
- if (pg->ps.type->status)
- sz += pg->ps.type->status(&pg->ps,
- &p->path, type, result + sz,
- maxlen - sz);
- }
- }
- break;
- case STATUSTYPE_IMA:
- sz = 0; /*reset the result pointer*/
- DMEMIT_TARGET_NAME_VERSION(ti->type);
- DMEMIT(",nr_priority_groups=%u", m->nr_priority_groups);
- pg_counter = 0;
- list_for_each_entry(pg, &m->priority_groups, list) {
- if (pg->bypassed)
- state = 'D'; /* Disabled */
- else if (pg == m->current_pg)
- state = 'A'; /* Currently Active */
- else
- state = 'E'; /* Enabled */
- DMEMIT(",pg_state_%d=%c", pg_counter, state);
- DMEMIT(",nr_pgpaths_%d=%u", pg_counter, pg->nr_pgpaths);
- DMEMIT(",path_selector_name_%d=%s", pg_counter, pg->ps.type->name);
- pgpath_counter = 0;
- list_for_each_entry(p, &pg->pgpaths, list) {
- DMEMIT(",path_name_%d_%d=%s,is_active_%d_%d=%c,fail_count_%d_%d=%u",
- pg_counter, pgpath_counter, p->path.dev->name,
- pg_counter, pgpath_counter, p->is_active ? 'A' : 'F',
- pg_counter, pgpath_counter, p->fail_count);
- if (pg->ps.type->status) {
- DMEMIT(",path_selector_status_%d_%d=",
- pg_counter, pgpath_counter);
- sz += pg->ps.type->status(&pg->ps, &p->path,
- type, result + sz,
- maxlen - sz);
- }
- pgpath_counter++;
- }
- pg_counter++;
- }
- DMEMIT(";");
- break;
- }
- spin_unlock_irqrestore(&m->lock, flags);
- }
- static int multipath_message(struct dm_target *ti, unsigned int argc, char **argv,
- char *result, unsigned int maxlen)
- {
- int r = -EINVAL;
- struct dm_dev *dev;
- struct multipath *m = ti->private;
- action_fn action;
- unsigned long flags;
- mutex_lock(&m->work_mutex);
- if (dm_suspended(ti)) {
- r = -EBUSY;
- goto out;
- }
- if (argc == 1) {
- if (!strcasecmp(argv[0], "queue_if_no_path")) {
- 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, __func__);
- disable_nopath_timeout(m);
- goto out;
- }
- }
- if (argc != 2) {
- DMWARN("Invalid multipath message arguments. Expected 2 arguments, got %d.", argc);
- goto out;
- }
- if (!strcasecmp(argv[0], "disable_group")) {
- r = bypass_pg_num(m, argv[1], true);
- goto out;
- } else if (!strcasecmp(argv[0], "enable_group")) {
- r = bypass_pg_num(m, argv[1], false);
- goto out;
- } else if (!strcasecmp(argv[0], "switch_group")) {
- r = switch_pg_num(m, argv[1]);
- goto out;
- } else if (!strcasecmp(argv[0], "reinstate_path"))
- action = reinstate_path;
- else if (!strcasecmp(argv[0], "fail_path"))
- action = fail_path;
- else {
- DMWARN("Unrecognised multipath message received: %s", argv[0]);
- goto out;
- }
- r = dm_get_device(ti, argv[1], dm_table_get_mode(ti->table), &dev);
- if (r) {
- DMWARN("message: error getting device %s",
- argv[1]);
- goto out;
- }
- r = action_dev(m, dev, action);
- dm_put_device(ti, dev);
- out:
- mutex_unlock(&m->work_mutex);
- return r;
- }
- static int multipath_prepare_ioctl(struct dm_target *ti,
- struct block_device **bdev)
- {
- struct multipath *m = ti->private;
- struct pgpath *pgpath;
- unsigned long flags;
- int r;
- pgpath = READ_ONCE(m->current_pgpath);
- if (!pgpath || !mpath_double_check_test_bit(MPATHF_QUEUE_IO, m))
- pgpath = choose_pgpath(m, 0);
- if (pgpath) {
- if (!mpath_double_check_test_bit(MPATHF_QUEUE_IO, m)) {
- *bdev = pgpath->path.dev->bdev;
- r = 0;
- } else {
- /* pg_init has not started or completed */
- r = -ENOTCONN;
- }
- } else {
- /* No path is available */
- r = -EIO;
- spin_lock_irqsave(&m->lock, flags);
- if (test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags))
- r = -ENOTCONN;
- spin_unlock_irqrestore(&m->lock, flags);
- }
- if (r == -ENOTCONN) {
- if (!READ_ONCE(m->current_pg)) {
- /* Path status changed, redo selection */
- (void) choose_pgpath(m, 0);
- }
- spin_lock_irqsave(&m->lock, flags);
- if (test_bit(MPATHF_PG_INIT_REQUIRED, &m->flags))
- (void) __pg_init_all_paths(m);
- spin_unlock_irqrestore(&m->lock, flags);
- dm_table_run_md_queue_async(m->ti->table);
- process_queued_io_list(m);
- }
- /*
- * Only pass ioctls through if the device sizes match exactly.
- */
- if (!r && ti->len != bdev_nr_sectors((*bdev)))
- return 1;
- return r;
- }
- static int multipath_iterate_devices(struct dm_target *ti,
- iterate_devices_callout_fn fn, void *data)
- {
- struct multipath *m = ti->private;
- struct priority_group *pg;
- struct pgpath *p;
- int ret = 0;
- list_for_each_entry(pg, &m->priority_groups, list) {
- list_for_each_entry(p, &pg->pgpaths, list) {
- ret = fn(ti, p->path.dev, ti->begin, ti->len, data);
- if (ret)
- goto out;
- }
- }
- out:
- return ret;
- }
- static int pgpath_busy(struct pgpath *pgpath)
- {
- struct request_queue *q = bdev_get_queue(pgpath->path.dev->bdev);
- return blk_lld_busy(q);
- }
- /*
- * We return "busy", only when we can map I/Os but underlying devices
- * are busy (so even if we map I/Os now, the I/Os will wait on
- * the underlying queue).
- * In other words, if we want to kill I/Os or queue them inside us
- * due to map unavailability, we don't return "busy". Otherwise,
- * dm core won't give us the I/Os and we can't do what we want.
- */
- static int multipath_busy(struct dm_target *ti)
- {
- bool busy = false, has_active = false;
- struct multipath *m = ti->private;
- struct priority_group *pg, *next_pg;
- struct pgpath *pgpath;
- /* pg_init in progress */
- if (atomic_read(&m->pg_init_in_progress))
- return true;
- /* no paths available, for blk-mq: rely on IO mapping to delay requeue */
- if (!atomic_read(&m->nr_valid_paths)) {
- unsigned long flags;
- spin_lock_irqsave(&m->lock, flags);
- if (test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) {
- spin_unlock_irqrestore(&m->lock, flags);
- return (m->queue_mode != DM_TYPE_REQUEST_BASED);
- }
- spin_unlock_irqrestore(&m->lock, flags);
- }
- /* Guess which priority_group will be used at next mapping time */
- pg = READ_ONCE(m->current_pg);
- next_pg = READ_ONCE(m->next_pg);
- if (unlikely(!READ_ONCE(m->current_pgpath) && next_pg))
- pg = next_pg;
- if (!pg) {
- /*
- * We don't know which pg will be used at next mapping time.
- * We don't call choose_pgpath() here to avoid to trigger
- * pg_init just by busy checking.
- * So we don't know whether underlying devices we will be using
- * at next mapping time are busy or not. Just try mapping.
- */
- return busy;
- }
- /*
- * If there is one non-busy active path at least, the path selector
- * will be able to select it. So we consider such a pg as not busy.
- */
- busy = true;
- list_for_each_entry(pgpath, &pg->pgpaths, list) {
- if (pgpath->is_active) {
- has_active = true;
- if (!pgpath_busy(pgpath)) {
- busy = false;
- break;
- }
- }
- }
- if (!has_active) {
- /*
- * No active path in this pg, so this pg won't be used and
- * the current_pg will be changed at next mapping time.
- * We need to try mapping to determine it.
- */
- busy = false;
- }
- return busy;
- }
- /*-----------------------------------------------------------------
- * Module setup
- *---------------------------------------------------------------*/
- static struct target_type multipath_target = {
- .name = "multipath",
- .version = {1, 14, 0},
- .features = DM_TARGET_SINGLETON | DM_TARGET_IMMUTABLE |
- DM_TARGET_PASSES_INTEGRITY,
- .module = THIS_MODULE,
- .ctr = multipath_ctr,
- .dtr = multipath_dtr,
- .clone_and_map_rq = multipath_clone_and_map,
- .release_clone_rq = multipath_release_clone,
- .rq_end_io = multipath_end_io,
- .map = multipath_map_bio,
- .end_io = multipath_end_io_bio,
- .presuspend = multipath_presuspend,
- .postsuspend = multipath_postsuspend,
- .resume = multipath_resume,
- .status = multipath_status,
- .message = multipath_message,
- .prepare_ioctl = multipath_prepare_ioctl,
- .iterate_devices = multipath_iterate_devices,
- .busy = multipath_busy,
- };
- static int __init dm_multipath_init(void)
- {
- int r;
- kmultipathd = alloc_workqueue("kmpathd", WQ_MEM_RECLAIM, 0);
- if (!kmultipathd) {
- DMERR("failed to create workqueue kmpathd");
- r = -ENOMEM;
- goto bad_alloc_kmultipathd;
- }
- /*
- * A separate workqueue is used to handle the device handlers
- * to avoid overloading existing workqueue. Overloading the
- * old workqueue would also create a bottleneck in the
- * path of the storage hardware device activation.
- */
- kmpath_handlerd = alloc_ordered_workqueue("kmpath_handlerd",
- WQ_MEM_RECLAIM);
- if (!kmpath_handlerd) {
- DMERR("failed to create workqueue kmpath_handlerd");
- r = -ENOMEM;
- goto bad_alloc_kmpath_handlerd;
- }
- r = dm_register_target(&multipath_target);
- if (r < 0) {
- DMERR("request-based register failed %d", r);
- r = -EINVAL;
- goto bad_register_target;
- }
- return 0;
- bad_register_target:
- destroy_workqueue(kmpath_handlerd);
- bad_alloc_kmpath_handlerd:
- destroy_workqueue(kmultipathd);
- bad_alloc_kmultipathd:
- return r;
- }
- static void __exit dm_multipath_exit(void)
- {
- destroy_workqueue(kmpath_handlerd);
- destroy_workqueue(kmultipathd);
- dm_unregister_target(&multipath_target);
- }
- module_init(dm_multipath_init);
- module_exit(dm_multipath_exit);
- module_param_named(queue_if_no_path_timeout_secs,
- queue_if_no_path_timeout_secs, ulong, S_IRUGO | S_IWUSR);
- MODULE_PARM_DESC(queue_if_no_path_timeout_secs, "No available paths queue IO timeout in seconds");
- MODULE_DESCRIPTION(DM_NAME " multipath target");
- MODULE_AUTHOR("Sistina Software <[email protected]>");
- MODULE_LICENSE("GPL");
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