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 suspended; /* Has dm core suspended our I/O? */
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 && !m->suspended)) {
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->queue_if_no_path = queue_if_no_path;
337 if (!m->queue_if_no_path)
338 queue_work(kmultipathd, &m->process_queued_ios);
340 spin_unlock_irqrestore(&m->lock, flags);
345 /*-----------------------------------------------------------------
346 * The multipath daemon is responsible for resubmitting queued ios.
347 *---------------------------------------------------------------*/
349 static void dispatch_queued_ios(struct multipath *m)
353 struct bio *bio = NULL, *next;
354 struct mpath_io *mpio;
355 union map_info *info;
357 spin_lock_irqsave(&m->lock, flags);
358 bio = bio_list_get(&m->queued_ios);
359 spin_unlock_irqrestore(&m->lock, flags);
365 info = dm_get_mapinfo(bio);
368 r = map_io(m, bio, mpio, 1);
370 bio_endio(bio, bio->bi_size, r);
372 generic_make_request(bio);
378 static void process_queued_ios(void *data)
380 struct multipath *m = (struct multipath *) data;
381 struct hw_handler *hwh = &m->hw_handler;
382 struct pgpath *pgpath;
383 unsigned init_required, must_queue = 0;
386 spin_lock_irqsave(&m->lock, flags);
388 if (!m->current_pgpath)
391 pgpath = m->current_pgpath;
393 if ((pgpath && m->queue_io) ||
394 (!pgpath && m->queue_if_no_path && !m->suspended))
397 init_required = m->pg_init_required;
399 m->pg_init_required = 0;
401 spin_unlock_irqrestore(&m->lock, flags);
404 hwh->type->pg_init(hwh, pgpath->pg->bypassed, &pgpath->path);
407 dispatch_queued_ios(m);
411 * An event is triggered whenever a path is taken out of use.
412 * Includes path failure and PG bypass.
414 static void trigger_event(void *data)
416 struct multipath *m = (struct multipath *) data;
418 dm_table_event(m->ti->table);
421 /*-----------------------------------------------------------------
422 * Constructor/argument parsing:
423 * <#multipath feature args> [<arg>]*
424 * <#hw_handler args> [hw_handler [<arg>]*]
426 * <initial priority group>
427 * [<selector> <#selector args> [<arg>]*
428 * <#paths> <#per-path selector args>
429 * [<path> [<arg>]* ]+ ]+
430 *---------------------------------------------------------------*/
437 #define ESTR(s) ("dm-multipath: " s)
439 static int read_param(struct param *param, char *str, unsigned *v, char **error)
442 (sscanf(str, "%u", v) != 1) ||
445 *error = param->error;
457 static char *shift(struct arg_set *as)
471 static void consume(struct arg_set *as, unsigned n)
473 BUG_ON (as->argc < n);
478 static int parse_path_selector(struct arg_set *as, struct priority_group *pg,
479 struct dm_target *ti)
482 struct path_selector_type *pst;
485 static struct param _params[] = {
486 {0, 1024, ESTR("invalid number of path selector args")},
489 pst = dm_get_path_selector(shift(as));
491 ti->error = ESTR("unknown path selector type");
495 r = read_param(_params, shift(as), &ps_argc, &ti->error);
499 r = pst->create(&pg->ps, ps_argc, as->argv);
501 dm_put_path_selector(pst);
502 ti->error = ESTR("path selector constructor failed");
507 consume(as, ps_argc);
512 static struct pgpath *parse_path(struct arg_set *as, struct path_selector *ps,
513 struct dm_target *ti)
518 /* we need at least a path arg */
520 ti->error = ESTR("no device given");
528 r = dm_get_device(ti, shift(as), ti->begin, ti->len,
529 dm_table_get_mode(ti->table), &p->path.dev);
531 ti->error = ESTR("error getting device");
535 r = ps->type->add_path(ps, &p->path, as->argc, as->argv, &ti->error);
537 dm_put_device(ti, p->path.dev);
548 static struct priority_group *parse_priority_group(struct arg_set *as,
550 struct dm_target *ti)
552 static struct param _params[] = {
553 {1, 1024, ESTR("invalid number of paths")},
554 {0, 1024, ESTR("invalid number of selector args")}
558 unsigned i, nr_selector_args, nr_params;
559 struct priority_group *pg;
563 ti->error = ESTR("not enough priority group aruments");
567 pg = alloc_priority_group();
569 ti->error = ESTR("couldn't allocate priority group");
574 r = parse_path_selector(as, pg, ti);
581 r = read_param(_params, shift(as), &pg->nr_pgpaths, &ti->error);
585 r = read_param(_params + 1, shift(as), &nr_selector_args, &ti->error);
589 nr_params = 1 + nr_selector_args;
590 for (i = 0; i < pg->nr_pgpaths; i++) {
591 struct pgpath *pgpath;
592 struct arg_set path_args;
594 if (as->argc < nr_params)
597 path_args.argc = nr_params;
598 path_args.argv = as->argv;
600 pgpath = parse_path(&path_args, &pg->ps, ti);
605 list_add_tail(&pgpath->list, &pg->pgpaths);
606 consume(as, nr_params);
612 free_priority_group(pg, ti);
616 static int parse_hw_handler(struct arg_set *as, struct multipath *m,
617 struct dm_target *ti)
620 struct hw_handler_type *hwht;
623 static struct param _params[] = {
624 {0, 1024, ESTR("invalid number of hardware handler args")},
627 r = read_param(_params, shift(as), &hw_argc, &ti->error);
634 hwht = dm_get_hw_handler(shift(as));
636 ti->error = ESTR("unknown hardware handler type");
640 r = hwht->create(&m->hw_handler, hw_argc - 1, as->argv);
642 dm_put_hw_handler(hwht);
643 ti->error = ESTR("hardware handler constructor failed");
647 m->hw_handler.type = hwht;
648 consume(as, hw_argc - 1);
653 static int parse_features(struct arg_set *as, struct multipath *m,
654 struct dm_target *ti)
659 static struct param _params[] = {
660 {0, 1, ESTR("invalid number of feature args")},
663 r = read_param(_params, shift(as), &argc, &ti->error);
670 if (!strnicmp(shift(as), MESG_STR("queue_if_no_path")))
671 return queue_if_no_path(m, 1);
673 ti->error = "Unrecognised multipath feature request";
678 static int multipath_ctr(struct dm_target *ti, unsigned int argc,
681 /* target parameters */
682 static struct param _params[] = {
683 {1, 1024, ESTR("invalid number of priority groups")},
684 {1, 1024, ESTR("invalid initial priority group number")},
690 unsigned pg_count = 0;
691 unsigned next_pg_num;
696 m = alloc_multipath();
698 ti->error = ESTR("can't allocate multipath");
702 r = parse_features(&as, m, ti);
706 r = parse_hw_handler(&as, m, ti);
710 r = read_param(_params, shift(&as), &m->nr_priority_groups, &ti->error);
714 r = read_param(_params + 1, shift(&as), &next_pg_num, &ti->error);
718 /* parse the priority groups */
720 struct priority_group *pg;
722 pg = parse_priority_group(&as, m, ti);
728 m->nr_valid_paths += pg->nr_pgpaths;
729 list_add_tail(&pg->list, &m->priority_groups);
731 pg->pg_num = pg_count;
736 if (pg_count != m->nr_priority_groups) {
737 ti->error = ESTR("priority group count mismatch");
752 static void multipath_dtr(struct dm_target *ti)
754 struct multipath *m = (struct multipath *) ti->private;
756 flush_workqueue(kmultipathd);
761 * Map bios, recording original fields for later in case we have to resubmit
763 static int multipath_map(struct dm_target *ti, struct bio *bio,
764 union map_info *map_context)
767 struct mpath_io *mpio;
768 struct multipath *m = (struct multipath *) ti->private;
770 if (bio_barrier(bio))
773 mpio = mempool_alloc(m->mpio_pool, GFP_NOIO);
774 dm_bio_record(&mpio->details, bio);
776 map_context->ptr = mpio;
777 bio->bi_rw |= (1 << BIO_RW_FAILFAST);
778 r = map_io(m, bio, mpio, 0);
780 mempool_free(mpio, m->mpio_pool);
786 * Take a path out of use.
788 static int fail_path(struct pgpath *pgpath)
791 struct multipath *m = pgpath->pg->m;
793 spin_lock_irqsave(&m->lock, flags);
795 if (!pgpath->path.is_active)
798 DMWARN("dm-multipath: Failing path %s.", pgpath->path.dev->name);
800 pgpath->pg->ps.type->fail_path(&pgpath->pg->ps, &pgpath->path);
801 pgpath->path.is_active = 0;
802 pgpath->fail_count++;
806 if (pgpath == m->current_pgpath)
807 m->current_pgpath = NULL;
809 queue_work(kmultipathd, &m->trigger_event);
812 spin_unlock_irqrestore(&m->lock, flags);
818 * Reinstate a previously-failed path
820 static int reinstate_path(struct pgpath *pgpath)
824 struct multipath *m = pgpath->pg->m;
826 spin_lock_irqsave(&m->lock, flags);
828 if (pgpath->path.is_active)
831 if (!pgpath->pg->ps.type) {
832 DMWARN("Reinstate path not supported by path selector %s",
833 pgpath->pg->ps.type->name);
838 r = pgpath->pg->ps.type->reinstate_path(&pgpath->pg->ps, &pgpath->path);
842 pgpath->path.is_active = 1;
844 m->current_pgpath = NULL;
845 if (!m->nr_valid_paths++)
846 queue_work(kmultipathd, &m->process_queued_ios);
848 queue_work(kmultipathd, &m->trigger_event);
851 spin_unlock_irqrestore(&m->lock, flags);
857 * Fail or reinstate all paths that match the provided struct dm_dev.
859 static int action_dev(struct multipath *m, struct dm_dev *dev,
863 struct pgpath *pgpath;
864 struct priority_group *pg;
866 list_for_each_entry(pg, &m->priority_groups, list) {
867 list_for_each_entry(pgpath, &pg->pgpaths, list) {
868 if (pgpath->path.dev == dev)
877 * Temporarily try to avoid having to use the specified PG
879 static void bypass_pg(struct multipath *m, struct priority_group *pg,
884 spin_lock_irqsave(&m->lock, flags);
886 pg->bypassed = bypassed;
887 m->current_pgpath = NULL;
888 m->current_pg = NULL;
890 spin_unlock_irqrestore(&m->lock, flags);
892 queue_work(kmultipathd, &m->trigger_event);
896 * Switch to using the specified PG from the next I/O that gets mapped
898 static int switch_pg_num(struct multipath *m, const char *pgstr)
900 struct priority_group *pg;
904 if (!pgstr || (sscanf(pgstr, "%u", &pgnum) != 1) || !pgnum ||
905 (pgnum > m->nr_priority_groups)) {
906 DMWARN("invalid PG number supplied to switch_pg_num");
910 spin_lock_irqsave(&m->lock, flags);
911 list_for_each_entry(pg, &m->priority_groups, list) {
916 m->current_pgpath = NULL;
917 m->current_pg = NULL;
920 spin_unlock_irqrestore(&m->lock, flags);
922 queue_work(kmultipathd, &m->trigger_event);
927 * Set/clear bypassed status of a PG.
928 * PGs are numbered upwards from 1 in the order they were declared.
930 static int bypass_pg_num(struct multipath *m, const char *pgstr, int bypassed)
932 struct priority_group *pg;
935 if (!pgstr || (sscanf(pgstr, "%u", &pgnum) != 1) || !pgnum ||
936 (pgnum > m->nr_priority_groups)) {
937 DMWARN("invalid PG number supplied to bypass_pg");
941 list_for_each_entry(pg, &m->priority_groups, list) {
946 bypass_pg(m, pg, bypassed);
951 * pg_init must call this when it has completed its initialisation
953 void dm_pg_init_complete(struct path *path, unsigned err_flags)
955 struct pgpath *pgpath = path_to_pgpath(path);
956 struct priority_group *pg = pgpath->pg;
957 struct multipath *m = pg->m;
960 /* We insist on failing the path if the PG is already bypassed. */
961 if (err_flags && pg->bypassed)
962 err_flags |= MP_FAIL_PATH;
964 if (err_flags & MP_FAIL_PATH)
967 if (err_flags & MP_BYPASS_PG)
970 spin_lock_irqsave(&m->lock, flags);
974 m->current_pgpath = NULL;
975 m->current_pg = NULL;
977 queue_work(kmultipathd, &m->process_queued_ios);
978 spin_unlock_irqrestore(&m->lock, flags);
984 static int do_end_io(struct multipath *m, struct bio *bio,
985 int error, struct mpath_io *mpio)
987 struct hw_handler *hwh = &m->hw_handler;
988 unsigned err_flags = MP_FAIL_PATH; /* Default behavior */
991 return 0; /* I/O complete */
993 if ((error == -EWOULDBLOCK) && bio_rw_ahead(bio))
996 if (error == -EOPNOTSUPP)
1000 if (!m->nr_valid_paths) {
1001 if (!m->queue_if_no_path || m->suspended) {
1002 spin_unlock(&m->lock);
1005 spin_unlock(&m->lock);
1009 spin_unlock(&m->lock);
1011 if (hwh->type && hwh->type->error)
1012 err_flags = hwh->type->error(hwh, bio);
1015 if (err_flags & MP_FAIL_PATH)
1016 fail_path(mpio->pgpath);
1018 if (err_flags & MP_BYPASS_PG)
1019 bypass_pg(m, mpio->pgpath->pg, 1);
1022 if (err_flags & MP_ERROR_IO)
1026 dm_bio_restore(&mpio->details, bio);
1028 /* queue for the daemon to resubmit or fail */
1029 spin_lock(&m->lock);
1030 bio_list_add(&m->queued_ios, bio);
1033 queue_work(kmultipathd, &m->process_queued_ios);
1034 spin_unlock(&m->lock);
1036 return 1; /* io not complete */
1039 static int multipath_end_io(struct dm_target *ti, struct bio *bio,
1040 int error, union map_info *map_context)
1042 struct multipath *m = (struct multipath *) ti->private;
1043 struct mpath_io *mpio = (struct mpath_io *) map_context->ptr;
1044 struct pgpath *pgpath = mpio->pgpath;
1045 struct path_selector *ps;
1048 r = do_end_io(m, bio, error, mpio);
1050 ps = &pgpath->pg->ps;
1051 if (ps->type->end_io)
1052 ps->type->end_io(ps, &pgpath->path);
1055 mempool_free(mpio, m->mpio_pool);
1061 * Suspend can't complete until all the I/O is processed so if
1062 * the last path failed we will now error any queued I/O.
1064 static void multipath_presuspend(struct dm_target *ti)
1066 struct multipath *m = (struct multipath *) ti->private;
1067 unsigned long flags;
1069 spin_lock_irqsave(&m->lock, flags);
1071 if (m->queue_if_no_path)
1072 queue_work(kmultipathd, &m->process_queued_ios);
1073 spin_unlock_irqrestore(&m->lock, flags);
1076 static void multipath_resume(struct dm_target *ti)
1078 struct multipath *m = (struct multipath *) ti->private;
1079 unsigned long flags;
1081 spin_lock_irqsave(&m->lock, flags);
1083 spin_unlock_irqrestore(&m->lock, flags);
1087 * Info output has the following format:
1088 * num_multipath_feature_args [multipath_feature_args]*
1089 * num_handler_status_args [handler_status_args]*
1090 * num_groups init_group_number
1091 * [A|D|E num_ps_status_args [ps_status_args]*
1092 * num_paths num_selector_args
1093 * [path_dev A|F fail_count [selector_args]* ]+ ]+
1095 * Table output has the following format (identical to the constructor string):
1096 * num_feature_args [features_args]*
1097 * num_handler_args hw_handler [hw_handler_args]*
1098 * num_groups init_group_number
1099 * [priority selector-name num_ps_args [ps_args]*
1100 * num_paths num_selector_args [path_dev [selector_args]* ]+ ]+
1102 static int multipath_status(struct dm_target *ti, status_type_t type,
1103 char *result, unsigned int maxlen)
1106 unsigned long flags;
1107 struct multipath *m = (struct multipath *) ti->private;
1108 struct hw_handler *hwh = &m->hw_handler;
1109 struct priority_group *pg;
1114 spin_lock_irqsave(&m->lock, flags);
1117 if (type == STATUSTYPE_INFO)
1118 DMEMIT("1 %u ", m->queue_size);
1119 else if (m->queue_if_no_path)
1120 DMEMIT("1 queue_if_no_path ");
1124 if (hwh->type && hwh->type->status)
1125 sz += hwh->type->status(hwh, type, result + sz, maxlen - sz);
1126 else if (!hwh->type || type == STATUSTYPE_INFO)
1129 DMEMIT("1 %s ", hwh->type->name);
1131 DMEMIT("%u ", m->nr_priority_groups);
1134 pg_num = m->next_pg->pg_num;
1135 else if (m->current_pg)
1136 pg_num = m->current_pg->pg_num;
1140 DMEMIT("%u ", pg_num);
1143 case STATUSTYPE_INFO:
1144 list_for_each_entry(pg, &m->priority_groups, list) {
1146 state = 'D'; /* Disabled */
1147 else if (pg == m->current_pg)
1148 state = 'A'; /* Currently Active */
1150 state = 'E'; /* Enabled */
1152 DMEMIT("%c ", state);
1154 if (pg->ps.type->status)
1155 sz += pg->ps.type->status(&pg->ps, NULL, type,
1161 DMEMIT("%u %u ", pg->nr_pgpaths,
1162 pg->ps.type->info_args);
1164 list_for_each_entry(p, &pg->pgpaths, list) {
1165 DMEMIT("%s %s %u ", p->path.dev->name,
1166 p->path.is_active ? "A" : "F",
1168 if (pg->ps.type->status)
1169 sz += pg->ps.type->status(&pg->ps,
1170 &p->path, type, result + sz,
1176 case STATUSTYPE_TABLE:
1177 list_for_each_entry(pg, &m->priority_groups, list) {
1178 DMEMIT("%s ", pg->ps.type->name);
1180 if (pg->ps.type->status)
1181 sz += pg->ps.type->status(&pg->ps, NULL, type,
1187 DMEMIT("%u %u ", pg->nr_pgpaths,
1188 pg->ps.type->table_args);
1190 list_for_each_entry(p, &pg->pgpaths, list) {
1191 DMEMIT("%s ", p->path.dev->name);
1192 if (pg->ps.type->status)
1193 sz += pg->ps.type->status(&pg->ps,
1194 &p->path, type, result + sz,
1201 spin_unlock_irqrestore(&m->lock, flags);
1206 static int multipath_message(struct dm_target *ti, unsigned argc, char **argv)
1210 struct multipath *m = (struct multipath *) ti->private;
1214 if (!strnicmp(argv[0], MESG_STR("queue_if_no_path")))
1215 return queue_if_no_path(m, 1);
1216 else if (!strnicmp(argv[0], MESG_STR("fail_if_no_path")))
1217 return queue_if_no_path(m, 0);
1223 if (!strnicmp(argv[0], MESG_STR("disable_group")))
1224 return bypass_pg_num(m, argv[1], 1);
1225 else if (!strnicmp(argv[0], MESG_STR("enable_group")))
1226 return bypass_pg_num(m, argv[1], 0);
1227 else if (!strnicmp(argv[0], MESG_STR("switch_group")))
1228 return switch_pg_num(m, argv[1]);
1229 else if (!strnicmp(argv[0], MESG_STR("reinstate_path")))
1230 action = reinstate_path;
1231 else if (!strnicmp(argv[0], MESG_STR("fail_path")))
1236 r = dm_get_device(ti, argv[1], ti->begin, ti->len,
1237 dm_table_get_mode(ti->table), &dev);
1239 DMWARN("dm-multipath message: error getting device %s",
1244 r = action_dev(m, dev, action);
1246 dm_put_device(ti, dev);
1251 DMWARN("Unrecognised multipath message received.");
1255 /*-----------------------------------------------------------------
1257 *---------------------------------------------------------------*/
1258 static struct target_type multipath_target = {
1259 .name = "multipath",
1260 .version = {1, 0, 4},
1261 .module = THIS_MODULE,
1262 .ctr = multipath_ctr,
1263 .dtr = multipath_dtr,
1264 .map = multipath_map,
1265 .end_io = multipath_end_io,
1266 .presuspend = multipath_presuspend,
1267 .resume = multipath_resume,
1268 .status = multipath_status,
1269 .message = multipath_message,
1272 static int __init dm_multipath_init(void)
1276 /* allocate a slab for the dm_ios */
1277 _mpio_cache = kmem_cache_create("dm_mpath", sizeof(struct mpath_io),
1282 r = dm_register_target(&multipath_target);
1284 DMERR("%s: register failed %d", multipath_target.name, r);
1285 kmem_cache_destroy(_mpio_cache);
1289 kmultipathd = create_workqueue("kmpathd");
1291 DMERR("%s: failed to create workqueue kmpathd",
1292 multipath_target.name);
1293 dm_unregister_target(&multipath_target);
1294 kmem_cache_destroy(_mpio_cache);
1298 DMINFO("dm-multipath version %u.%u.%u loaded",
1299 multipath_target.version[0], multipath_target.version[1],
1300 multipath_target.version[2]);
1305 static void __exit dm_multipath_exit(void)
1309 destroy_workqueue(kmultipathd);
1311 r = dm_unregister_target(&multipath_target);
1313 DMERR("%s: target unregister failed %d",
1314 multipath_target.name, r);
1315 kmem_cache_destroy(_mpio_cache);
1318 EXPORT_SYMBOL_GPL(dm_pg_init_complete);
1320 module_init(dm_multipath_init);
1321 module_exit(dm_multipath_exit);
1323 MODULE_DESCRIPTION(DM_NAME " multipath target");
1324 MODULE_AUTHOR("Sistina Software <dm-devel@redhat.com>");
1325 MODULE_LICENSE("GPL");