2 * Copyright (C) 2003 Sistina Software Limited.
3 * Copyright (C) 2004-2005 Red Hat, Inc. All rights reserved.
5 * This file is released under the GPL.
9 #include "dm-path-selector.h"
10 #include "dm-hw-handler.h"
11 #include "dm-bio-list.h"
12 #include "dm-bio-record.h"
14 #include <linux/ctype.h>
15 #include <linux/init.h>
16 #include <linux/mempool.h>
17 #include <linux/module.h>
18 #include <linux/pagemap.h>
19 #include <linux/slab.h>
20 #include <linux/time.h>
21 #include <linux/workqueue.h>
22 #include <asm/atomic.h>
24 #define MESG_STR(x) x, sizeof(x)
28 struct list_head list;
30 struct priority_group *pg; /* Owning PG */
31 unsigned fail_count; /* Cumulative failure count */
36 #define path_to_pgpath(__pgp) container_of((__pgp), struct pgpath, path)
39 * Paths are grouped into Priority Groups and numbered from 1 upwards.
40 * Each has a path selector which controls which path gets used.
42 struct priority_group {
43 struct list_head list;
45 struct multipath *m; /* Owning multipath instance */
46 struct path_selector ps;
48 unsigned pg_num; /* Reference number */
49 unsigned bypassed; /* Temporarily bypass this PG? */
51 unsigned nr_pgpaths; /* Number of paths in PG */
52 struct list_head pgpaths;
55 /* Multipath context */
57 struct list_head list;
62 struct hw_handler hw_handler;
63 unsigned nr_priority_groups;
64 struct list_head priority_groups;
65 unsigned pg_init_required; /* pg_init needs calling? */
67 unsigned nr_valid_paths; /* Total number of usable paths */
68 struct pgpath *current_pgpath;
69 struct priority_group *current_pg;
70 struct priority_group *next_pg; /* Switch to this PG if set */
71 unsigned repeat_count; /* I/Os left before calling PS again */
73 unsigned queue_io; /* Must we queue all I/O? */
74 unsigned queue_if_no_path; /* Queue I/O if last path fails? */
75 unsigned saved_queue_if_no_path;/* Saved state during suspension */
77 struct work_struct process_queued_ios;
78 struct bio_list queued_ios;
81 struct work_struct trigger_event;
84 * We must use a mempool of mpath_io structs so that we
85 * can resubmit bios on error.
91 * Context information attached to each bio we process.
94 struct pgpath *pgpath;
95 struct dm_bio_details details;
98 typedef int (*action_fn) (struct pgpath *pgpath);
100 #define MIN_IOS 256 /* Mempool size */
102 static kmem_cache_t *_mpio_cache;
104 struct workqueue_struct *kmultipathd;
105 static void process_queued_ios(void *data);
106 static void trigger_event(void *data);
109 /*-----------------------------------------------
110 * Allocation routines
111 *-----------------------------------------------*/
113 static struct pgpath *alloc_pgpath(void)
115 struct pgpath *pgpath = kmalloc(sizeof(*pgpath), GFP_KERNEL);
118 memset(pgpath, 0, sizeof(*pgpath));
119 pgpath->path.is_active = 1;
125 static inline void free_pgpath(struct pgpath *pgpath)
130 static struct priority_group *alloc_priority_group(void)
132 struct priority_group *pg;
134 pg = kmalloc(sizeof(*pg), GFP_KERNEL);
138 memset(pg, 0, sizeof(*pg));
139 INIT_LIST_HEAD(&pg->pgpaths);
144 static void free_pgpaths(struct list_head *pgpaths, struct dm_target *ti)
146 struct pgpath *pgpath, *tmp;
148 list_for_each_entry_safe(pgpath, tmp, pgpaths, list) {
149 list_del(&pgpath->list);
150 dm_put_device(ti, pgpath->path.dev);
155 static void free_priority_group(struct priority_group *pg,
156 struct dm_target *ti)
158 struct path_selector *ps = &pg->ps;
161 ps->type->destroy(ps);
162 dm_put_path_selector(ps->type);
165 free_pgpaths(&pg->pgpaths, ti);
169 static struct multipath *alloc_multipath(void)
173 m = kmalloc(sizeof(*m), GFP_KERNEL);
175 memset(m, 0, sizeof(*m));
176 INIT_LIST_HEAD(&m->priority_groups);
177 spin_lock_init(&m->lock);
179 INIT_WORK(&m->process_queued_ios, process_queued_ios, m);
180 INIT_WORK(&m->trigger_event, trigger_event, m);
181 m->mpio_pool = mempool_create(MIN_IOS, mempool_alloc_slab,
182 mempool_free_slab, _mpio_cache);
192 static void free_multipath(struct multipath *m)
194 struct priority_group *pg, *tmp;
195 struct hw_handler *hwh = &m->hw_handler;
197 list_for_each_entry_safe(pg, tmp, &m->priority_groups, list) {
199 free_priority_group(pg, m->ti);
203 hwh->type->destroy(hwh);
204 dm_put_hw_handler(hwh->type);
207 mempool_destroy(m->mpio_pool);
212 /*-----------------------------------------------
214 *-----------------------------------------------*/
216 static void __switch_pg(struct multipath *m, struct pgpath *pgpath)
218 struct hw_handler *hwh = &m->hw_handler;
220 m->current_pg = pgpath->pg;
222 /* Must we initialise the PG first, and queue I/O till it's ready? */
223 if (hwh->type && hwh->type->pg_init) {
224 m->pg_init_required = 1;
227 m->pg_init_required = 0;
232 static int __choose_path_in_pg(struct multipath *m, struct priority_group *pg)
236 path = pg->ps.type->select_path(&pg->ps, &m->repeat_count);
240 m->current_pgpath = path_to_pgpath(path);
242 if (m->current_pg != pg)
243 __switch_pg(m, m->current_pgpath);
248 static void __choose_pgpath(struct multipath *m)
250 struct priority_group *pg;
251 unsigned bypassed = 1;
253 if (!m->nr_valid_paths)
256 /* Were we instructed to switch PG? */
260 if (!__choose_path_in_pg(m, pg))
264 /* Don't change PG until it has no remaining paths */
265 if (m->current_pg && !__choose_path_in_pg(m, m->current_pg))
269 * Loop through priority groups until we find a valid path.
270 * First time we skip PGs marked 'bypassed'.
271 * Second time we only try the ones we skipped.
274 list_for_each_entry(pg, &m->priority_groups, list) {
275 if (pg->bypassed == bypassed)
277 if (!__choose_path_in_pg(m, pg))
280 } while (bypassed--);
283 m->current_pgpath = NULL;
284 m->current_pg = NULL;
287 static int map_io(struct multipath *m, struct bio *bio, struct mpath_io *mpio,
292 struct pgpath *pgpath;
294 spin_lock_irqsave(&m->lock, flags);
296 /* Do we need to select a new pgpath? */
297 if (!m->current_pgpath ||
298 (!m->queue_io && (m->repeat_count && --m->repeat_count == 0)))
301 pgpath = m->current_pgpath;
306 if ((pgpath && m->queue_io) ||
307 (!pgpath && m->queue_if_no_path)) {
308 /* Queue for the daemon to resubmit */
309 bio_list_add(&m->queued_ios, bio);
311 if (m->pg_init_required || !m->queue_io)
312 queue_work(kmultipathd, &m->process_queued_ios);
316 r = -EIO; /* Failed */
318 bio->bi_bdev = pgpath->path.dev->bdev;
320 mpio->pgpath = pgpath;
322 spin_unlock_irqrestore(&m->lock, flags);
328 * If we run out of usable paths, should we queue I/O or error it?
330 static int queue_if_no_path(struct multipath *m, unsigned queue_if_no_path)
334 spin_lock_irqsave(&m->lock, flags);
336 m->saved_queue_if_no_path = m->queue_if_no_path;
337 m->queue_if_no_path = queue_if_no_path;
338 if (!m->queue_if_no_path)
339 queue_work(kmultipathd, &m->process_queued_ios);
341 spin_unlock_irqrestore(&m->lock, flags);
346 /*-----------------------------------------------------------------
347 * The multipath daemon is responsible for resubmitting queued ios.
348 *---------------------------------------------------------------*/
350 static void dispatch_queued_ios(struct multipath *m)
354 struct bio *bio = NULL, *next;
355 struct mpath_io *mpio;
356 union map_info *info;
358 spin_lock_irqsave(&m->lock, flags);
359 bio = bio_list_get(&m->queued_ios);
360 spin_unlock_irqrestore(&m->lock, flags);
366 info = dm_get_mapinfo(bio);
369 r = map_io(m, bio, mpio, 1);
371 bio_endio(bio, bio->bi_size, r);
373 generic_make_request(bio);
379 static void process_queued_ios(void *data)
381 struct multipath *m = (struct multipath *) data;
382 struct hw_handler *hwh = &m->hw_handler;
383 struct pgpath *pgpath;
384 unsigned init_required, must_queue = 0;
387 spin_lock_irqsave(&m->lock, flags);
389 if (!m->current_pgpath)
392 pgpath = m->current_pgpath;
394 if ((pgpath && m->queue_io) ||
395 (!pgpath && m->queue_if_no_path))
398 init_required = m->pg_init_required;
400 m->pg_init_required = 0;
402 spin_unlock_irqrestore(&m->lock, flags);
405 hwh->type->pg_init(hwh, pgpath->pg->bypassed, &pgpath->path);
408 dispatch_queued_ios(m);
412 * An event is triggered whenever a path is taken out of use.
413 * Includes path failure and PG bypass.
415 static void trigger_event(void *data)
417 struct multipath *m = (struct multipath *) data;
419 dm_table_event(m->ti->table);
422 /*-----------------------------------------------------------------
423 * Constructor/argument parsing:
424 * <#multipath feature args> [<arg>]*
425 * <#hw_handler args> [hw_handler [<arg>]*]
427 * <initial priority group>
428 * [<selector> <#selector args> [<arg>]*
429 * <#paths> <#per-path selector args>
430 * [<path> [<arg>]* ]+ ]+
431 *---------------------------------------------------------------*/
438 #define ESTR(s) ("dm-multipath: " s)
440 static int read_param(struct param *param, char *str, unsigned *v, char **error)
443 (sscanf(str, "%u", v) != 1) ||
446 *error = param->error;
458 static char *shift(struct arg_set *as)
472 static void consume(struct arg_set *as, unsigned n)
474 BUG_ON (as->argc < n);
479 static int parse_path_selector(struct arg_set *as, struct priority_group *pg,
480 struct dm_target *ti)
483 struct path_selector_type *pst;
486 static struct param _params[] = {
487 {0, 1024, ESTR("invalid number of path selector args")},
490 pst = dm_get_path_selector(shift(as));
492 ti->error = ESTR("unknown path selector type");
496 r = read_param(_params, shift(as), &ps_argc, &ti->error);
500 r = pst->create(&pg->ps, ps_argc, as->argv);
502 dm_put_path_selector(pst);
503 ti->error = ESTR("path selector constructor failed");
508 consume(as, ps_argc);
513 static struct pgpath *parse_path(struct arg_set *as, struct path_selector *ps,
514 struct dm_target *ti)
519 /* we need at least a path arg */
521 ti->error = ESTR("no device given");
529 r = dm_get_device(ti, shift(as), ti->begin, ti->len,
530 dm_table_get_mode(ti->table), &p->path.dev);
532 ti->error = ESTR("error getting device");
536 r = ps->type->add_path(ps, &p->path, as->argc, as->argv, &ti->error);
538 dm_put_device(ti, p->path.dev);
549 static struct priority_group *parse_priority_group(struct arg_set *as,
551 struct dm_target *ti)
553 static struct param _params[] = {
554 {1, 1024, ESTR("invalid number of paths")},
555 {0, 1024, ESTR("invalid number of selector args")}
559 unsigned i, nr_selector_args, nr_params;
560 struct priority_group *pg;
564 ti->error = ESTR("not enough priority group aruments");
568 pg = alloc_priority_group();
570 ti->error = ESTR("couldn't allocate priority group");
575 r = parse_path_selector(as, pg, ti);
582 r = read_param(_params, shift(as), &pg->nr_pgpaths, &ti->error);
586 r = read_param(_params + 1, shift(as), &nr_selector_args, &ti->error);
590 nr_params = 1 + nr_selector_args;
591 for (i = 0; i < pg->nr_pgpaths; i++) {
592 struct pgpath *pgpath;
593 struct arg_set path_args;
595 if (as->argc < nr_params)
598 path_args.argc = nr_params;
599 path_args.argv = as->argv;
601 pgpath = parse_path(&path_args, &pg->ps, ti);
606 list_add_tail(&pgpath->list, &pg->pgpaths);
607 consume(as, nr_params);
613 free_priority_group(pg, ti);
617 static int parse_hw_handler(struct arg_set *as, struct multipath *m,
618 struct dm_target *ti)
621 struct hw_handler_type *hwht;
624 static struct param _params[] = {
625 {0, 1024, ESTR("invalid number of hardware handler args")},
628 r = read_param(_params, shift(as), &hw_argc, &ti->error);
635 hwht = dm_get_hw_handler(shift(as));
637 ti->error = ESTR("unknown hardware handler type");
641 r = hwht->create(&m->hw_handler, hw_argc - 1, as->argv);
643 dm_put_hw_handler(hwht);
644 ti->error = ESTR("hardware handler constructor failed");
648 m->hw_handler.type = hwht;
649 consume(as, hw_argc - 1);
654 static int parse_features(struct arg_set *as, struct multipath *m,
655 struct dm_target *ti)
660 static struct param _params[] = {
661 {0, 1, ESTR("invalid number of feature args")},
664 r = read_param(_params, shift(as), &argc, &ti->error);
671 if (!strnicmp(shift(as), MESG_STR("queue_if_no_path")))
672 return queue_if_no_path(m, 1);
674 ti->error = "Unrecognised multipath feature request";
679 static int multipath_ctr(struct dm_target *ti, unsigned int argc,
682 /* target parameters */
683 static struct param _params[] = {
684 {1, 1024, ESTR("invalid number of priority groups")},
685 {1, 1024, ESTR("invalid initial priority group number")},
691 unsigned pg_count = 0;
692 unsigned next_pg_num;
697 m = alloc_multipath();
699 ti->error = ESTR("can't allocate multipath");
703 r = parse_features(&as, m, ti);
707 r = parse_hw_handler(&as, m, ti);
711 r = read_param(_params, shift(&as), &m->nr_priority_groups, &ti->error);
715 r = read_param(_params + 1, shift(&as), &next_pg_num, &ti->error);
719 /* parse the priority groups */
721 struct priority_group *pg;
723 pg = parse_priority_group(&as, m, ti);
729 m->nr_valid_paths += pg->nr_pgpaths;
730 list_add_tail(&pg->list, &m->priority_groups);
732 pg->pg_num = pg_count;
737 if (pg_count != m->nr_priority_groups) {
738 ti->error = ESTR("priority group count mismatch");
753 static void multipath_dtr(struct dm_target *ti)
755 struct multipath *m = (struct multipath *) ti->private;
757 flush_workqueue(kmultipathd);
762 * Map bios, recording original fields for later in case we have to resubmit
764 static int multipath_map(struct dm_target *ti, struct bio *bio,
765 union map_info *map_context)
768 struct mpath_io *mpio;
769 struct multipath *m = (struct multipath *) ti->private;
771 if (bio_barrier(bio))
774 mpio = mempool_alloc(m->mpio_pool, GFP_NOIO);
775 dm_bio_record(&mpio->details, bio);
777 map_context->ptr = mpio;
778 bio->bi_rw |= (1 << BIO_RW_FAILFAST);
779 r = map_io(m, bio, mpio, 0);
781 mempool_free(mpio, m->mpio_pool);
787 * Take a path out of use.
789 static int fail_path(struct pgpath *pgpath)
792 struct multipath *m = pgpath->pg->m;
794 spin_lock_irqsave(&m->lock, flags);
796 if (!pgpath->path.is_active)
799 DMWARN("dm-multipath: Failing path %s.", pgpath->path.dev->name);
801 pgpath->pg->ps.type->fail_path(&pgpath->pg->ps, &pgpath->path);
802 pgpath->path.is_active = 0;
803 pgpath->fail_count++;
807 if (pgpath == m->current_pgpath)
808 m->current_pgpath = NULL;
810 queue_work(kmultipathd, &m->trigger_event);
813 spin_unlock_irqrestore(&m->lock, flags);
819 * Reinstate a previously-failed path
821 static int reinstate_path(struct pgpath *pgpath)
825 struct multipath *m = pgpath->pg->m;
827 spin_lock_irqsave(&m->lock, flags);
829 if (pgpath->path.is_active)
832 if (!pgpath->pg->ps.type) {
833 DMWARN("Reinstate path not supported by path selector %s",
834 pgpath->pg->ps.type->name);
839 r = pgpath->pg->ps.type->reinstate_path(&pgpath->pg->ps, &pgpath->path);
843 pgpath->path.is_active = 1;
845 m->current_pgpath = NULL;
846 if (!m->nr_valid_paths++)
847 queue_work(kmultipathd, &m->process_queued_ios);
849 queue_work(kmultipathd, &m->trigger_event);
852 spin_unlock_irqrestore(&m->lock, flags);
858 * Fail or reinstate all paths that match the provided struct dm_dev.
860 static int action_dev(struct multipath *m, struct dm_dev *dev,
864 struct pgpath *pgpath;
865 struct priority_group *pg;
867 list_for_each_entry(pg, &m->priority_groups, list) {
868 list_for_each_entry(pgpath, &pg->pgpaths, list) {
869 if (pgpath->path.dev == dev)
878 * Temporarily try to avoid having to use the specified PG
880 static void bypass_pg(struct multipath *m, struct priority_group *pg,
885 spin_lock_irqsave(&m->lock, flags);
887 pg->bypassed = bypassed;
888 m->current_pgpath = NULL;
889 m->current_pg = NULL;
891 spin_unlock_irqrestore(&m->lock, flags);
893 queue_work(kmultipathd, &m->trigger_event);
897 * Switch to using the specified PG from the next I/O that gets mapped
899 static int switch_pg_num(struct multipath *m, const char *pgstr)
901 struct priority_group *pg;
905 if (!pgstr || (sscanf(pgstr, "%u", &pgnum) != 1) || !pgnum ||
906 (pgnum > m->nr_priority_groups)) {
907 DMWARN("invalid PG number supplied to switch_pg_num");
911 spin_lock_irqsave(&m->lock, flags);
912 list_for_each_entry(pg, &m->priority_groups, list) {
917 m->current_pgpath = NULL;
918 m->current_pg = NULL;
921 spin_unlock_irqrestore(&m->lock, flags);
923 queue_work(kmultipathd, &m->trigger_event);
928 * Set/clear bypassed status of a PG.
929 * PGs are numbered upwards from 1 in the order they were declared.
931 static int bypass_pg_num(struct multipath *m, const char *pgstr, int bypassed)
933 struct priority_group *pg;
936 if (!pgstr || (sscanf(pgstr, "%u", &pgnum) != 1) || !pgnum ||
937 (pgnum > m->nr_priority_groups)) {
938 DMWARN("invalid PG number supplied to bypass_pg");
942 list_for_each_entry(pg, &m->priority_groups, list) {
947 bypass_pg(m, pg, bypassed);
952 * pg_init must call this when it has completed its initialisation
954 void dm_pg_init_complete(struct path *path, unsigned err_flags)
956 struct pgpath *pgpath = path_to_pgpath(path);
957 struct priority_group *pg = pgpath->pg;
958 struct multipath *m = pg->m;
961 /* We insist on failing the path if the PG is already bypassed. */
962 if (err_flags && pg->bypassed)
963 err_flags |= MP_FAIL_PATH;
965 if (err_flags & MP_FAIL_PATH)
968 if (err_flags & MP_BYPASS_PG)
971 spin_lock_irqsave(&m->lock, flags);
975 m->current_pgpath = NULL;
976 m->current_pg = NULL;
978 queue_work(kmultipathd, &m->process_queued_ios);
979 spin_unlock_irqrestore(&m->lock, flags);
985 static int do_end_io(struct multipath *m, struct bio *bio,
986 int error, struct mpath_io *mpio)
988 struct hw_handler *hwh = &m->hw_handler;
989 unsigned err_flags = MP_FAIL_PATH; /* Default behavior */
992 return 0; /* I/O complete */
994 if ((error == -EWOULDBLOCK) && bio_rw_ahead(bio))
997 if (error == -EOPNOTSUPP)
1000 spin_lock(&m->lock);
1001 if (!m->nr_valid_paths) {
1002 if (!m->queue_if_no_path) {
1003 spin_unlock(&m->lock);
1006 spin_unlock(&m->lock);
1010 spin_unlock(&m->lock);
1012 if (hwh->type && hwh->type->error)
1013 err_flags = hwh->type->error(hwh, bio);
1016 if (err_flags & MP_FAIL_PATH)
1017 fail_path(mpio->pgpath);
1019 if (err_flags & MP_BYPASS_PG)
1020 bypass_pg(m, mpio->pgpath->pg, 1);
1023 if (err_flags & MP_ERROR_IO)
1027 dm_bio_restore(&mpio->details, bio);
1029 /* queue for the daemon to resubmit or fail */
1030 spin_lock(&m->lock);
1031 bio_list_add(&m->queued_ios, bio);
1034 queue_work(kmultipathd, &m->process_queued_ios);
1035 spin_unlock(&m->lock);
1037 return 1; /* io not complete */
1040 static int multipath_end_io(struct dm_target *ti, struct bio *bio,
1041 int error, union map_info *map_context)
1043 struct multipath *m = (struct multipath *) ti->private;
1044 struct mpath_io *mpio = (struct mpath_io *) map_context->ptr;
1045 struct pgpath *pgpath = mpio->pgpath;
1046 struct path_selector *ps;
1049 r = do_end_io(m, bio, error, mpio);
1051 ps = &pgpath->pg->ps;
1052 if (ps->type->end_io)
1053 ps->type->end_io(ps, &pgpath->path);
1056 mempool_free(mpio, m->mpio_pool);
1062 * Suspend can't complete until all the I/O is processed so if
1063 * the last path fails we must error any remaining I/O.
1064 * Note that if the freeze_bdev fails while suspending, the
1065 * queue_if_no_path state is lost - userspace should reset it.
1067 static void multipath_presuspend(struct dm_target *ti)
1069 struct multipath *m = (struct multipath *) ti->private;
1071 queue_if_no_path(m, 0);
1075 * Restore the queue_if_no_path setting.
1077 static void multipath_resume(struct dm_target *ti)
1079 struct multipath *m = (struct multipath *) ti->private;
1080 unsigned long flags;
1082 spin_lock_irqsave(&m->lock, flags);
1083 m->queue_if_no_path = m->saved_queue_if_no_path;
1084 spin_unlock_irqrestore(&m->lock, flags);
1088 * Info output has the following format:
1089 * num_multipath_feature_args [multipath_feature_args]*
1090 * num_handler_status_args [handler_status_args]*
1091 * num_groups init_group_number
1092 * [A|D|E num_ps_status_args [ps_status_args]*
1093 * num_paths num_selector_args
1094 * [path_dev A|F fail_count [selector_args]* ]+ ]+
1096 * Table output has the following format (identical to the constructor string):
1097 * num_feature_args [features_args]*
1098 * num_handler_args hw_handler [hw_handler_args]*
1099 * num_groups init_group_number
1100 * [priority selector-name num_ps_args [ps_args]*
1101 * num_paths num_selector_args [path_dev [selector_args]* ]+ ]+
1103 static int multipath_status(struct dm_target *ti, status_type_t type,
1104 char *result, unsigned int maxlen)
1107 unsigned long flags;
1108 struct multipath *m = (struct multipath *) ti->private;
1109 struct hw_handler *hwh = &m->hw_handler;
1110 struct priority_group *pg;
1115 spin_lock_irqsave(&m->lock, flags);
1118 if (type == STATUSTYPE_INFO)
1119 DMEMIT("1 %u ", m->queue_size);
1120 else if (m->queue_if_no_path)
1121 DMEMIT("1 queue_if_no_path ");
1125 if (hwh->type && hwh->type->status)
1126 sz += hwh->type->status(hwh, type, result + sz, maxlen - sz);
1127 else if (!hwh->type || type == STATUSTYPE_INFO)
1130 DMEMIT("1 %s ", hwh->type->name);
1132 DMEMIT("%u ", m->nr_priority_groups);
1135 pg_num = m->next_pg->pg_num;
1136 else if (m->current_pg)
1137 pg_num = m->current_pg->pg_num;
1141 DMEMIT("%u ", pg_num);
1144 case STATUSTYPE_INFO:
1145 list_for_each_entry(pg, &m->priority_groups, list) {
1147 state = 'D'; /* Disabled */
1148 else if (pg == m->current_pg)
1149 state = 'A'; /* Currently Active */
1151 state = 'E'; /* Enabled */
1153 DMEMIT("%c ", state);
1155 if (pg->ps.type->status)
1156 sz += pg->ps.type->status(&pg->ps, NULL, type,
1162 DMEMIT("%u %u ", pg->nr_pgpaths,
1163 pg->ps.type->info_args);
1165 list_for_each_entry(p, &pg->pgpaths, list) {
1166 DMEMIT("%s %s %u ", p->path.dev->name,
1167 p->path.is_active ? "A" : "F",
1169 if (pg->ps.type->status)
1170 sz += pg->ps.type->status(&pg->ps,
1171 &p->path, type, result + sz,
1177 case STATUSTYPE_TABLE:
1178 list_for_each_entry(pg, &m->priority_groups, list) {
1179 DMEMIT("%s ", pg->ps.type->name);
1181 if (pg->ps.type->status)
1182 sz += pg->ps.type->status(&pg->ps, NULL, type,
1188 DMEMIT("%u %u ", pg->nr_pgpaths,
1189 pg->ps.type->table_args);
1191 list_for_each_entry(p, &pg->pgpaths, list) {
1192 DMEMIT("%s ", p->path.dev->name);
1193 if (pg->ps.type->status)
1194 sz += pg->ps.type->status(&pg->ps,
1195 &p->path, type, result + sz,
1202 spin_unlock_irqrestore(&m->lock, flags);
1207 static int multipath_message(struct dm_target *ti, unsigned argc, char **argv)
1211 struct multipath *m = (struct multipath *) ti->private;
1215 if (!strnicmp(argv[0], MESG_STR("queue_if_no_path")))
1216 return queue_if_no_path(m, 1);
1217 else if (!strnicmp(argv[0], MESG_STR("fail_if_no_path")))
1218 return queue_if_no_path(m, 0);
1224 if (!strnicmp(argv[0], MESG_STR("disable_group")))
1225 return bypass_pg_num(m, argv[1], 1);
1226 else if (!strnicmp(argv[0], MESG_STR("enable_group")))
1227 return bypass_pg_num(m, argv[1], 0);
1228 else if (!strnicmp(argv[0], MESG_STR("switch_group")))
1229 return switch_pg_num(m, argv[1]);
1230 else if (!strnicmp(argv[0], MESG_STR("reinstate_path")))
1231 action = reinstate_path;
1232 else if (!strnicmp(argv[0], MESG_STR("fail_path")))
1237 r = dm_get_device(ti, argv[1], ti->begin, ti->len,
1238 dm_table_get_mode(ti->table), &dev);
1240 DMWARN("dm-multipath message: error getting device %s",
1245 r = action_dev(m, dev, action);
1247 dm_put_device(ti, dev);
1252 DMWARN("Unrecognised multipath message received.");
1256 /*-----------------------------------------------------------------
1258 *---------------------------------------------------------------*/
1259 static struct target_type multipath_target = {
1260 .name = "multipath",
1261 .version = {1, 0, 4},
1262 .module = THIS_MODULE,
1263 .ctr = multipath_ctr,
1264 .dtr = multipath_dtr,
1265 .map = multipath_map,
1266 .end_io = multipath_end_io,
1267 .presuspend = multipath_presuspend,
1268 .resume = multipath_resume,
1269 .status = multipath_status,
1270 .message = multipath_message,
1273 static int __init dm_multipath_init(void)
1277 /* allocate a slab for the dm_ios */
1278 _mpio_cache = kmem_cache_create("dm_mpath", sizeof(struct mpath_io),
1283 r = dm_register_target(&multipath_target);
1285 DMERR("%s: register failed %d", multipath_target.name, r);
1286 kmem_cache_destroy(_mpio_cache);
1290 kmultipathd = create_workqueue("kmpathd");
1292 DMERR("%s: failed to create workqueue kmpathd",
1293 multipath_target.name);
1294 dm_unregister_target(&multipath_target);
1295 kmem_cache_destroy(_mpio_cache);
1299 DMINFO("dm-multipath version %u.%u.%u loaded",
1300 multipath_target.version[0], multipath_target.version[1],
1301 multipath_target.version[2]);
1306 static void __exit dm_multipath_exit(void)
1310 destroy_workqueue(kmultipathd);
1312 r = dm_unregister_target(&multipath_target);
1314 DMERR("%s: target unregister failed %d",
1315 multipath_target.name, r);
1316 kmem_cache_destroy(_mpio_cache);
1319 EXPORT_SYMBOL_GPL(dm_pg_init_complete);
1321 module_init(dm_multipath_init);
1322 module_exit(dm_multipath_exit);
1324 MODULE_DESCRIPTION(DM_NAME " multipath target");
1325 MODULE_AUTHOR("Sistina Software <dm-devel@redhat.com>");
1326 MODULE_LICENSE("GPL");