| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Alasdair G. Kergon | 3515 | 38.19% | 16 | 9.41% |
| Mike Snitzer | 3143 | 34.15% | 52 | 30.59% |
| Chandra Seetharaman | 672 | 7.30% | 8 | 4.71% |
| Kiyoshi Ueda | 400 | 4.35% | 7 | 4.12% |
| Christoph Hellwig | 247 | 2.68% | 15 | 8.82% |
| Hannes Reinecke | 195 | 2.12% | 13 | 7.65% |
| Dave Wysochanski | 190 | 2.06% | 1 | 0.59% |
| Bart Van Assche | 176 | 1.91% | 12 | 7.06% |
| Mike Anderson | 155 | 1.68% | 2 | 1.18% |
| Milan Broz | 68 | 0.74% | 2 | 1.18% |
| tang.junhui | 46 | 0.50% | 3 | 1.76% |
| Mikulas Patocka | 46 | 0.50% | 8 | 4.71% |
| Jun'ichi Nomura | 44 | 0.48% | 3 | 1.76% |
| Benjamin Marzinski | 43 | 0.47% | 2 | 1.18% |
| Michał Mirosław | 41 | 0.45% | 2 | 1.18% |
| monty_pavel@sina.com | 37 | 0.40% | 1 | 0.59% |
| Johannes Thumshirn | 25 | 0.27% | 1 | 0.59% |
| wuzhouhui | 23 | 0.25% | 1 | 0.59% |
| Shiva Krishna Merla | 21 | 0.23% | 1 | 0.59% |
| Lukas Wunner | 18 | 0.20% | 1 | 0.59% |
| Keith Busch | 18 | 0.20% | 2 | 1.18% |
| David Howells | 13 | 0.14% | 1 | 0.59% |
| Michael Christie | 11 | 0.12% | 1 | 0.59% |
| Will Deacon | 10 | 0.11% | 1 | 0.59% |
| Jose Castillo | 9 | 0.10% | 1 | 0.59% |
| Tejun Heo | 8 | 0.09% | 1 | 0.59% |
| Ming Lei | 8 | 0.09% | 2 | 1.18% |
| Eric Biggers | 5 | 0.05% | 1 | 0.59% |
| Babu Moger | 5 | 0.05% | 2 | 1.18% |
| Steffen Maier | 3 | 0.03% | 1 | 0.59% |
| Josef 'Jeff' Sipek | 2 | 0.02% | 1 | 0.59% |
| Wei Yongjun | 2 | 0.02% | 1 | 0.59% |
| Jens Axboe | 1 | 0.01% | 1 | 0.59% |
| Arun Sharma | 1 | 0.01% | 1 | 0.59% |
| Wang Sheng-Hui | 1 | 0.01% | 1 | 0.59% |
| Dan Carpenter | 1 | 0.01% | 1 | 0.59% |
| Total | 9203 | 170 |
/* * 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/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) -1) /* Path properties */ struct pgpath { struct list_head list; struct priority_group *pg; /* Owning PG */ unsigned 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 pg_num; /* Reference number */ unsigned 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 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 pg_init_retries; /* Number of times to retry pg_init */ unsigned 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; }; /* * Context information attached to each io we process. */ struct dm_mpath_io { struct pgpath *pgpath; size_t nr_bytes; }; 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); /*----------------------------------------------- * 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? */ /*----------------------------------------------- * 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; } 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_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) { 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 bypassed = 1; if (!atomic_read(&m->nr_valid_paths)) { clear_bit(MPATHF_QUEUE_IO, &m->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) set_bit(MPATHF_PG_INIT_DELAY_RETRY, &m->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() * report the function name and line number of the function from which * it has been invoked. */ #define dm_report_EIO(m) \ do { \ struct mapped_device *md = dm_table_get_md((m)->ti->table); \ \ pr_debug("%s: returning EIO; QIFNP = %d; SQIFNP = %d; DNFS = %d\n", \ dm_device_name(md), \ 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. * * If MPATHF_QUEUE_IF_NO_PATH and MPATHF_SAVED_QUEUE_IF_NO_PATH hold * the same value then we are not between multipath_presuspend() * and multipath_resume() calls and we have no need to check * for the DMF_NOFLUSH_SUSPENDING flag. */ static bool __must_push_back(struct multipath *m, unsigned long flags) { return ((test_bit(MPATHF_QUEUE_IF_NO_PATH, &flags) != test_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &flags)) && dm_noflush_suspending(m->ti)); } /* * Following functions use READ_ONCE to get atomic access to * all m->flags to avoid taking spinlock */ static bool must_push_back_rq(struct multipath *m) { unsigned long flags = READ_ONCE(m->flags); return test_bit(MPATHF_QUEUE_IF_NO_PATH, &flags) || __must_push_back(m, flags); } static bool must_push_back_bio(struct multipath *m) { unsigned long flags = READ_ONCE(m->flags); return __must_push_back(m, flags); } /* * 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 || !test_bit(MPATHF_QUEUE_IO, &m->flags)) 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 (test_bit(MPATHF_QUEUE_IO, &m->flags) || test_bit(MPATHF_PG_INIT_REQUIRED, &m->flags)) { 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_get_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->rq_disk = bdev->bd_disk; 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) { blk_put_request(clone); } /* * Map cloned bios (bio-based multipath) */ static struct pgpath *__map_bio(struct multipath *m, struct bio *bio) { struct pgpath *pgpath; unsigned long flags; bool queue_io; /* Do we need to select a new pgpath? */ pgpath = READ_ONCE(m->current_pgpath); queue_io = test_bit(MPATHF_QUEUE_IO, &m->flags); if (!pgpath || !queue_io) pgpath = choose_pgpath(m, bio->bi_iter.bi_size); if ((pgpath && queue_io) || (!pgpath && test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags))) { /* Queue for the daemon to resubmit */ spin_lock_irqsave(&m->lock, flags); bio_list_add(&m->queued_bios, bio); spin_unlock_irqrestore(&m->lock, flags); /* PG_INIT_REQUIRED cannot be set without QUEUE_IO */ if (queue_io || test_bit(MPATHF_PG_INIT_REQUIRED, &m->flags)) pg_init_all_paths(m); else if (!queue_io) queue_work(kmultipathd, &m->process_queued_bios); return ERR_PTR(-EAGAIN); } return pgpath; } static struct pgpath *__map_bio_fast(struct multipath *m, struct bio *bio) { struct pgpath *pgpath; unsigned long flags; /* Do we need to select a new pgpath? */ /* * FIXME: currently only switching path if no path (due to failure, etc) * - which negates the point of using a path selector */ pgpath = READ_ONCE(m->current_pgpath); if (!pgpath) pgpath = choose_pgpath(m, bio->bi_iter.bi_size); if (!pgpath) { if (test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) { /* Queue for the daemon to resubmit */ spin_lock_irqsave(&m->lock, flags); bio_list_add(&m->queued_bios, bio); spin_unlock_irqrestore(&m->lock, flags); queue_work(kmultipathd, &m->process_queued_bios); return ERR_PTR(-EAGAIN); } return NULL; } return pgpath; } static int __multipath_map_bio(struct multipath *m, struct bio *bio, struct dm_mpath_io *mpio) { struct pgpath *pgpath; if (!m->hw_handler_name) pgpath = __map_bio_fast(m, bio); else pgpath = __map_bio(m, bio); if (IS_ERR(pgpath)) return DM_MAPIO_SUBMITTED; if (!pgpath) { if (must_push_back_bio(m)) return DM_MAPIO_REQUEUE; dm_report_EIO(m); return DM_MAPIO_KILL; } mpio->pgpath = pgpath; 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: generic_make_request(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) { unsigned long flags; spin_lock_irqsave(&m->lock, flags); assign_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &m->flags, (save_old_value && test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) || (!save_old_value && queue_if_no_path)); assign_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags, queue_if_no_path); 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; } /* * 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 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 (test_bit(MPATHF_RETAIN_ATTACHED_HW_HANDLER, &m->flags)) { 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) { char b[BDEVNAME_SIZE]; printk(KERN_INFO "dm-mpath: retaining handler on device %s\n", bdevname(bdev, b)); 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); 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: kfree(attached_handler_name); 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 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 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 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); 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 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 pg_count = 0; unsigned next_pg_num; 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 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; } ti->num_flush_bios = 1; ti->num_discard_bios = 1; ti->num_write_same_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) { set_bit(MPATHF_PG_INIT_DISABLED, &m->flags); smp_mb__after_atomic(); if (atomic_read(&m->pg_init_in_progress)) flush_workqueue(kmpath_handlerd); multipath_wait_for_pg_init_completion(m); clear_bit(MPATHF_PG_INIT_DISABLED, &m->flags); smp_mb__after_atomic(); } 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; 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("Failing path %s.", 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); 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 nr_valid_paths; spin_lock_irqsave(&m->lock, flags); if (pgpath->is_active) goto out; DMWARN("Reinstating path %s.", 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); } 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 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 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 = 1; /* fall through */ 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) == 0 && !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); } 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) == 0 && !test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) { if (must_push_back_bio(m)) { r = DM_ENDIO_REQUEUE; } else { dm_report_EIO(m); *error = BLK_STS_IOERR; } goto done; } spin_lock_irqsave(&m->lock, flags); bio_list_add(&m->queued_bios, clone); spin_unlock_irqrestore(&m->lock, flags); if (!test_bit(MPATHF_QUEUE_IO, &m->flags)) queue_work(kmultipathd, &m->process_queued_bios); 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); } return r; } /* * Suspend 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. */ static void multipath_presuspend(struct dm_target *ti) { struct multipath *m = ti->private; queue_if_no_path(m, false, true); } 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); assign_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 status_flags, char *result, unsigned maxlen) { int sz = 0; unsigned long flags; struct multipath *m = ti->private; struct priority_group *pg; struct pgpath *p; unsigned 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; } spin_unlock_irqrestore(&m->lock, flags); } static int multipath_message(struct dm_target *ti, unsigned argc, char **argv, char *result, unsigned maxlen) { int r = -EINVAL; struct dm_dev *dev; struct multipath *m = ti->private; action_fn action; 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); goto out; } else if (!strcasecmp(argv[0], "fail_if_no_path")) { r = queue_if_no_path(m, false, false); 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 *current_pgpath; int r; current_pgpath = READ_ONCE(m->current_pgpath); if (!current_pgpath) current_pgpath = choose_pgpath(m, 0); if (current_pgpath) { if (!test_bit(MPATHF_QUEUE_IO, &m->flags)) { *bdev = current_pgpath->path.dev->bdev; r = 0; } else { /* pg_init has not started or completed */ r = -ENOTCONN; } } else { /* No path is available */ if (test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) r = -ENOTCONN; else r = -EIO; } if (r == -ENOTCONN) { if (!READ_ONCE(m->current_pg)) { /* Path status changed, redo selection */ (void) choose_pgpath(m, 0); } if (test_bit(MPATHF_PG_INIT_REQUIRED, &m->flags)) pg_init_all_paths(m); 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 != i_size_read((*bdev)->bd_inode) >> SECTOR_SHIFT) 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) && test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) return (m->queue_mode != DM_TYPE_REQUEST_BASED); /* 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, 13, 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_DESCRIPTION(DM_NAME " multipath target"); MODULE_AUTHOR("Sistina Software <dm-devel@redhat.com>"); MODULE_LICENSE("GPL");
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