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"
13 #include "dm-uevent.h"
15 #include <linux/ctype.h>
16 #include <linux/init.h>
17 #include <linux/mempool.h>
18 #include <linux/module.h>
19 #include <linux/pagemap.h>
20 #include <linux/slab.h>
21 #include <linux/time.h>
22 #include <linux/workqueue.h>
23 #include <scsi/scsi_dh.h>
24 #include <asm/atomic.h>
26 #define DM_MSG_PREFIX "multipath"
27 #define MESG_STR(x) x, sizeof(x)
31 struct list_head list;
33 struct priority_group *pg; /* Owning PG */
34 unsigned fail_count; /* Cumulative failure count */
39 #define path_to_pgpath(__pgp) container_of((__pgp), struct pgpath, path)
42 * Paths are grouped into Priority Groups and numbered from 1 upwards.
43 * Each has a path selector which controls which path gets used.
45 struct priority_group {
46 struct list_head list;
48 struct multipath *m; /* Owning multipath instance */
49 struct path_selector ps;
51 unsigned pg_num; /* Reference number */
52 unsigned bypassed; /* Temporarily bypass this PG? */
54 unsigned nr_pgpaths; /* Number of paths in PG */
55 struct list_head pgpaths;
58 /* Multipath context */
60 struct list_head list;
65 const char *hw_handler_name;
66 unsigned nr_priority_groups;
67 struct list_head priority_groups;
68 unsigned pg_init_required; /* pg_init needs calling? */
69 unsigned pg_init_in_progress; /* Only one pg_init allowed at once */
71 unsigned nr_valid_paths; /* Total number of usable paths */
72 struct pgpath *current_pgpath;
73 struct priority_group *current_pg;
74 struct priority_group *next_pg; /* Switch to this PG if set */
75 unsigned repeat_count; /* I/Os left before calling PS again */
77 unsigned queue_io; /* Must we queue all I/O? */
78 unsigned queue_if_no_path; /* Queue I/O if last path fails? */
79 unsigned saved_queue_if_no_path;/* Saved state during suspension */
80 unsigned pg_init_retries; /* Number of times to retry pg_init */
81 unsigned pg_init_count; /* Number of times pg_init called */
83 struct work_struct process_queued_ios;
84 struct bio_list queued_ios;
87 struct work_struct trigger_event;
90 * We must use a mempool of dm_mpath_io structs so that we
91 * can resubmit bios on error.
97 * Context information attached to each bio we process.
100 struct pgpath *pgpath;
101 struct dm_bio_details details;
104 typedef int (*action_fn) (struct pgpath *pgpath);
106 #define MIN_IOS 256 /* Mempool size */
108 static struct kmem_cache *_mpio_cache;
110 static struct workqueue_struct *kmultipathd;
111 static void process_queued_ios(struct work_struct *work);
112 static void trigger_event(struct work_struct *work);
113 static void pg_init_done(struct dm_path *, int);
116 /*-----------------------------------------------
117 * Allocation routines
118 *-----------------------------------------------*/
120 static struct pgpath *alloc_pgpath(void)
122 struct pgpath *pgpath = kzalloc(sizeof(*pgpath), GFP_KERNEL);
125 pgpath->path.is_active = 1;
130 static void free_pgpath(struct pgpath *pgpath)
135 static struct priority_group *alloc_priority_group(void)
137 struct priority_group *pg;
139 pg = kzalloc(sizeof(*pg), GFP_KERNEL);
142 INIT_LIST_HEAD(&pg->pgpaths);
147 static void free_pgpaths(struct list_head *pgpaths, struct dm_target *ti)
149 struct pgpath *pgpath, *tmp;
151 list_for_each_entry_safe(pgpath, tmp, pgpaths, list) {
152 list_del(&pgpath->list);
153 dm_put_device(ti, pgpath->path.dev);
158 static void free_priority_group(struct priority_group *pg,
159 struct dm_target *ti)
161 struct path_selector *ps = &pg->ps;
164 ps->type->destroy(ps);
165 dm_put_path_selector(ps->type);
168 free_pgpaths(&pg->pgpaths, ti);
172 static struct multipath *alloc_multipath(struct dm_target *ti)
176 m = kzalloc(sizeof(*m), GFP_KERNEL);
178 INIT_LIST_HEAD(&m->priority_groups);
179 spin_lock_init(&m->lock);
181 INIT_WORK(&m->process_queued_ios, process_queued_ios);
182 INIT_WORK(&m->trigger_event, trigger_event);
183 m->mpio_pool = mempool_create_slab_pool(MIN_IOS, _mpio_cache);
195 static void free_multipath(struct multipath *m)
197 struct priority_group *pg, *tmp;
199 list_for_each_entry_safe(pg, tmp, &m->priority_groups, list) {
201 free_priority_group(pg, m->ti);
204 kfree(m->hw_handler_name);
205 mempool_destroy(m->mpio_pool);
210 /*-----------------------------------------------
212 *-----------------------------------------------*/
214 static void __switch_pg(struct multipath *m, struct pgpath *pgpath)
216 m->current_pg = pgpath->pg;
218 /* Must we initialise the PG first, and queue I/O till it's ready? */
219 if (m->hw_handler_name) {
220 m->pg_init_required = 1;
223 m->pg_init_required = 0;
227 m->pg_init_count = 0;
230 static int __choose_path_in_pg(struct multipath *m, struct priority_group *pg)
232 struct dm_path *path;
234 path = pg->ps.type->select_path(&pg->ps, &m->repeat_count);
238 m->current_pgpath = path_to_pgpath(path);
240 if (m->current_pg != pg)
241 __switch_pg(m, m->current_pgpath);
246 static void __choose_pgpath(struct multipath *m)
248 struct priority_group *pg;
249 unsigned bypassed = 1;
251 if (!m->nr_valid_paths)
254 /* Were we instructed to switch PG? */
258 if (!__choose_path_in_pg(m, pg))
262 /* Don't change PG until it has no remaining paths */
263 if (m->current_pg && !__choose_path_in_pg(m, m->current_pg))
267 * Loop through priority groups until we find a valid path.
268 * First time we skip PGs marked 'bypassed'.
269 * Second time we only try the ones we skipped.
272 list_for_each_entry(pg, &m->priority_groups, list) {
273 if (pg->bypassed == bypassed)
275 if (!__choose_path_in_pg(m, pg))
278 } while (bypassed--);
281 m->current_pgpath = NULL;
282 m->current_pg = NULL;
286 * Check whether bios must be queued in the device-mapper core rather
287 * than here in the target.
289 * m->lock must be held on entry.
291 * If m->queue_if_no_path and m->saved_queue_if_no_path hold the
292 * same value then we are not between multipath_presuspend()
293 * and multipath_resume() calls and we have no need to check
294 * for the DMF_NOFLUSH_SUSPENDING flag.
296 static int __must_push_back(struct multipath *m)
298 return (m->queue_if_no_path != m->saved_queue_if_no_path &&
299 dm_noflush_suspending(m->ti));
302 static int map_io(struct multipath *m, struct bio *bio,
303 struct dm_mpath_io *mpio, unsigned was_queued)
305 int r = DM_MAPIO_REMAPPED;
307 struct pgpath *pgpath;
309 spin_lock_irqsave(&m->lock, flags);
311 /* Do we need to select a new pgpath? */
312 if (!m->current_pgpath ||
313 (!m->queue_io && (m->repeat_count && --m->repeat_count == 0)))
316 pgpath = m->current_pgpath;
321 if ((pgpath && m->queue_io) ||
322 (!pgpath && m->queue_if_no_path)) {
323 /* Queue for the daemon to resubmit */
324 bio_list_add(&m->queued_ios, bio);
326 if ((m->pg_init_required && !m->pg_init_in_progress) ||
328 queue_work(kmultipathd, &m->process_queued_ios);
330 r = DM_MAPIO_SUBMITTED;
332 bio->bi_bdev = pgpath->path.dev->bdev;
333 else if (__must_push_back(m))
334 r = DM_MAPIO_REQUEUE;
336 r = -EIO; /* Failed */
338 mpio->pgpath = pgpath;
340 spin_unlock_irqrestore(&m->lock, flags);
346 * If we run out of usable paths, should we queue I/O or error it?
348 static int queue_if_no_path(struct multipath *m, unsigned queue_if_no_path,
349 unsigned save_old_value)
353 spin_lock_irqsave(&m->lock, flags);
356 m->saved_queue_if_no_path = m->queue_if_no_path;
358 m->saved_queue_if_no_path = queue_if_no_path;
359 m->queue_if_no_path = queue_if_no_path;
360 if (!m->queue_if_no_path && m->queue_size)
361 queue_work(kmultipathd, &m->process_queued_ios);
363 spin_unlock_irqrestore(&m->lock, flags);
368 /*-----------------------------------------------------------------
369 * The multipath daemon is responsible for resubmitting queued ios.
370 *---------------------------------------------------------------*/
372 static void dispatch_queued_ios(struct multipath *m)
376 struct bio *bio = NULL, *next;
377 struct dm_mpath_io *mpio;
378 union map_info *info;
380 spin_lock_irqsave(&m->lock, flags);
381 bio = bio_list_get(&m->queued_ios);
382 spin_unlock_irqrestore(&m->lock, flags);
388 info = dm_get_mapinfo(bio);
391 r = map_io(m, bio, mpio, 1);
394 else if (r == DM_MAPIO_REMAPPED)
395 generic_make_request(bio);
396 else if (r == DM_MAPIO_REQUEUE)
397 bio_endio(bio, -EIO);
403 static void process_queued_ios(struct work_struct *work)
405 struct multipath *m =
406 container_of(work, struct multipath, process_queued_ios);
407 struct pgpath *pgpath = NULL;
408 unsigned init_required = 0, must_queue = 1;
411 spin_lock_irqsave(&m->lock, flags);
416 if (!m->current_pgpath)
419 pgpath = m->current_pgpath;
421 if ((pgpath && !m->queue_io) ||
422 (!pgpath && !m->queue_if_no_path))
425 if (m->pg_init_required && !m->pg_init_in_progress) {
427 m->pg_init_required = 0;
428 m->pg_init_in_progress = 1;
433 spin_unlock_irqrestore(&m->lock, flags);
436 struct dm_path *path = &pgpath->path;
437 int ret = scsi_dh_activate(bdev_get_queue(path->dev->bdev));
438 pg_init_done(path, ret);
442 dispatch_queued_ios(m);
446 * An event is triggered whenever a path is taken out of use.
447 * Includes path failure and PG bypass.
449 static void trigger_event(struct work_struct *work)
451 struct multipath *m =
452 container_of(work, struct multipath, trigger_event);
454 dm_table_event(m->ti->table);
457 /*-----------------------------------------------------------------
458 * Constructor/argument parsing:
459 * <#multipath feature args> [<arg>]*
460 * <#hw_handler args> [hw_handler [<arg>]*]
462 * <initial priority group>
463 * [<selector> <#selector args> [<arg>]*
464 * <#paths> <#per-path selector args>
465 * [<path> [<arg>]* ]+ ]+
466 *---------------------------------------------------------------*/
473 static int read_param(struct param *param, char *str, unsigned *v, char **error)
476 (sscanf(str, "%u", v) != 1) ||
479 *error = param->error;
491 static char *shift(struct arg_set *as)
505 static void consume(struct arg_set *as, unsigned n)
507 BUG_ON (as->argc < n);
512 static int parse_path_selector(struct arg_set *as, struct priority_group *pg,
513 struct dm_target *ti)
516 struct path_selector_type *pst;
519 static struct param _params[] = {
520 {0, 1024, "invalid number of path selector args"},
523 pst = dm_get_path_selector(shift(as));
525 ti->error = "unknown path selector type";
529 r = read_param(_params, shift(as), &ps_argc, &ti->error);
533 r = pst->create(&pg->ps, ps_argc, as->argv);
535 dm_put_path_selector(pst);
536 ti->error = "path selector constructor failed";
541 consume(as, ps_argc);
546 static struct pgpath *parse_path(struct arg_set *as, struct path_selector *ps,
547 struct dm_target *ti)
552 /* we need at least a path arg */
554 ti->error = "no device given";
562 r = dm_get_device(ti, shift(as), ti->begin, ti->len,
563 dm_table_get_mode(ti->table), &p->path.dev);
565 ti->error = "error getting device";
569 r = ps->type->add_path(ps, &p->path, as->argc, as->argv, &ti->error);
571 dm_put_device(ti, p->path.dev);
582 static struct priority_group *parse_priority_group(struct arg_set *as,
585 static struct param _params[] = {
586 {1, 1024, "invalid number of paths"},
587 {0, 1024, "invalid number of selector args"}
591 unsigned i, nr_selector_args, nr_params;
592 struct priority_group *pg;
593 struct dm_target *ti = m->ti;
597 ti->error = "not enough priority group aruments";
601 pg = alloc_priority_group();
603 ti->error = "couldn't allocate priority group";
608 r = parse_path_selector(as, pg, ti);
615 r = read_param(_params, shift(as), &pg->nr_pgpaths, &ti->error);
619 r = read_param(_params + 1, shift(as), &nr_selector_args, &ti->error);
623 nr_params = 1 + nr_selector_args;
624 for (i = 0; i < pg->nr_pgpaths; i++) {
625 struct pgpath *pgpath;
626 struct arg_set path_args;
628 if (as->argc < nr_params)
631 path_args.argc = nr_params;
632 path_args.argv = as->argv;
634 pgpath = parse_path(&path_args, &pg->ps, ti);
639 list_add_tail(&pgpath->list, &pg->pgpaths);
640 consume(as, nr_params);
646 free_priority_group(pg, ti);
650 static int parse_hw_handler(struct arg_set *as, struct multipath *m)
653 struct dm_target *ti = m->ti;
655 static struct param _params[] = {
656 {0, 1024, "invalid number of hardware handler args"},
659 if (read_param(_params, shift(as), &hw_argc, &ti->error))
665 m->hw_handler_name = kstrdup(shift(as), GFP_KERNEL);
666 request_module("scsi_dh_%s", m->hw_handler_name);
667 if (scsi_dh_handler_exist(m->hw_handler_name) == 0) {
668 ti->error = "unknown hardware handler type";
671 consume(as, hw_argc - 1);
676 static int parse_features(struct arg_set *as, struct multipath *m)
680 struct dm_target *ti = m->ti;
681 const char *param_name;
683 static struct param _params[] = {
684 {0, 3, "invalid number of feature args"},
685 {1, 50, "pg_init_retries must be between 1 and 50"},
688 r = read_param(_params, shift(as), &argc, &ti->error);
696 param_name = shift(as);
699 if (!strnicmp(param_name, MESG_STR("queue_if_no_path"))) {
700 r = queue_if_no_path(m, 1, 0);
704 if (!strnicmp(param_name, MESG_STR("pg_init_retries")) &&
706 r = read_param(_params + 1, shift(as),
707 &m->pg_init_retries, &ti->error);
712 ti->error = "Unrecognised multipath feature request";
714 } while (argc && !r);
719 static int multipath_ctr(struct dm_target *ti, unsigned int argc,
722 /* target parameters */
723 static struct param _params[] = {
724 {1, 1024, "invalid number of priority groups"},
725 {1, 1024, "invalid initial priority group number"},
731 unsigned pg_count = 0;
732 unsigned next_pg_num;
737 m = alloc_multipath(ti);
739 ti->error = "can't allocate multipath";
743 r = parse_features(&as, m);
747 r = parse_hw_handler(&as, m);
751 r = read_param(_params, shift(&as), &m->nr_priority_groups, &ti->error);
755 r = read_param(_params + 1, shift(&as), &next_pg_num, &ti->error);
759 /* parse the priority groups */
761 struct priority_group *pg;
763 pg = parse_priority_group(&as, m);
769 m->nr_valid_paths += pg->nr_pgpaths;
770 list_add_tail(&pg->list, &m->priority_groups);
772 pg->pg_num = pg_count;
777 if (pg_count != m->nr_priority_groups) {
778 ti->error = "priority group count mismatch";
790 static void multipath_dtr(struct dm_target *ti)
792 struct multipath *m = (struct multipath *) ti->private;
794 flush_workqueue(kmultipathd);
799 * Map bios, recording original fields for later in case we have to resubmit
801 static int multipath_map(struct dm_target *ti, struct bio *bio,
802 union map_info *map_context)
805 struct dm_mpath_io *mpio;
806 struct multipath *m = (struct multipath *) ti->private;
808 mpio = mempool_alloc(m->mpio_pool, GFP_NOIO);
809 dm_bio_record(&mpio->details, bio);
811 map_context->ptr = mpio;
812 bio->bi_rw |= (1 << BIO_RW_FAILFAST);
813 r = map_io(m, bio, mpio, 0);
814 if (r < 0 || r == DM_MAPIO_REQUEUE)
815 mempool_free(mpio, m->mpio_pool);
821 * Take a path out of use.
823 static int fail_path(struct pgpath *pgpath)
826 struct multipath *m = pgpath->pg->m;
828 spin_lock_irqsave(&m->lock, flags);
830 if (!pgpath->path.is_active)
833 DMWARN("Failing path %s.", pgpath->path.dev->name);
835 pgpath->pg->ps.type->fail_path(&pgpath->pg->ps, &pgpath->path);
836 pgpath->path.is_active = 0;
837 pgpath->fail_count++;
841 if (pgpath == m->current_pgpath)
842 m->current_pgpath = NULL;
844 dm_path_uevent(DM_UEVENT_PATH_FAILED, m->ti,
845 pgpath->path.dev->name, m->nr_valid_paths);
847 queue_work(kmultipathd, &m->trigger_event);
850 spin_unlock_irqrestore(&m->lock, flags);
856 * Reinstate a previously-failed path
858 static int reinstate_path(struct pgpath *pgpath)
862 struct multipath *m = pgpath->pg->m;
864 spin_lock_irqsave(&m->lock, flags);
866 if (pgpath->path.is_active)
869 if (!pgpath->pg->ps.type) {
870 DMWARN("Reinstate path not supported by path selector %s",
871 pgpath->pg->ps.type->name);
876 r = pgpath->pg->ps.type->reinstate_path(&pgpath->pg->ps, &pgpath->path);
880 pgpath->path.is_active = 1;
882 m->current_pgpath = NULL;
883 if (!m->nr_valid_paths++ && m->queue_size)
884 queue_work(kmultipathd, &m->process_queued_ios);
886 dm_path_uevent(DM_UEVENT_PATH_REINSTATED, m->ti,
887 pgpath->path.dev->name, m->nr_valid_paths);
889 queue_work(kmultipathd, &m->trigger_event);
892 spin_unlock_irqrestore(&m->lock, flags);
898 * Fail or reinstate all paths that match the provided struct dm_dev.
900 static int action_dev(struct multipath *m, struct dm_dev *dev,
904 struct pgpath *pgpath;
905 struct priority_group *pg;
907 list_for_each_entry(pg, &m->priority_groups, list) {
908 list_for_each_entry(pgpath, &pg->pgpaths, list) {
909 if (pgpath->path.dev == dev)
918 * Temporarily try to avoid having to use the specified PG
920 static void bypass_pg(struct multipath *m, struct priority_group *pg,
925 spin_lock_irqsave(&m->lock, flags);
927 pg->bypassed = bypassed;
928 m->current_pgpath = NULL;
929 m->current_pg = NULL;
931 spin_unlock_irqrestore(&m->lock, flags);
933 queue_work(kmultipathd, &m->trigger_event);
937 * Switch to using the specified PG from the next I/O that gets mapped
939 static int switch_pg_num(struct multipath *m, const char *pgstr)
941 struct priority_group *pg;
945 if (!pgstr || (sscanf(pgstr, "%u", &pgnum) != 1) || !pgnum ||
946 (pgnum > m->nr_priority_groups)) {
947 DMWARN("invalid PG number supplied to switch_pg_num");
951 spin_lock_irqsave(&m->lock, flags);
952 list_for_each_entry(pg, &m->priority_groups, list) {
957 m->current_pgpath = NULL;
958 m->current_pg = NULL;
961 spin_unlock_irqrestore(&m->lock, flags);
963 queue_work(kmultipathd, &m->trigger_event);
968 * Set/clear bypassed status of a PG.
969 * PGs are numbered upwards from 1 in the order they were declared.
971 static int bypass_pg_num(struct multipath *m, const char *pgstr, int bypassed)
973 struct priority_group *pg;
976 if (!pgstr || (sscanf(pgstr, "%u", &pgnum) != 1) || !pgnum ||
977 (pgnum > m->nr_priority_groups)) {
978 DMWARN("invalid PG number supplied to bypass_pg");
982 list_for_each_entry(pg, &m->priority_groups, list) {
987 bypass_pg(m, pg, bypassed);
992 * Should we retry pg_init immediately?
994 static int pg_init_limit_reached(struct multipath *m, struct pgpath *pgpath)
997 int limit_reached = 0;
999 spin_lock_irqsave(&m->lock, flags);
1001 if (m->pg_init_count <= m->pg_init_retries)
1002 m->pg_init_required = 1;
1006 spin_unlock_irqrestore(&m->lock, flags);
1008 return limit_reached;
1012 * pg_init must call this when it has completed its initialisation
1014 void dm_pg_init_complete(struct dm_path *path, unsigned err_flags)
1016 struct pgpath *pgpath = path_to_pgpath(path);
1017 struct priority_group *pg = pgpath->pg;
1018 struct multipath *m = pg->m;
1019 unsigned long flags;
1022 * If requested, retry pg_init until maximum number of retries exceeded.
1023 * If retry not requested and PG already bypassed, always fail the path.
1025 if (err_flags & MP_RETRY) {
1026 if (pg_init_limit_reached(m, pgpath))
1027 err_flags |= MP_FAIL_PATH;
1028 } else if (err_flags && pg->bypassed)
1029 err_flags |= MP_FAIL_PATH;
1031 if (err_flags & MP_FAIL_PATH)
1034 if (err_flags & MP_BYPASS_PG)
1035 bypass_pg(m, pg, 1);
1037 spin_lock_irqsave(&m->lock, flags);
1038 if (err_flags & ~MP_RETRY) {
1039 m->current_pgpath = NULL;
1040 m->current_pg = NULL;
1041 } else if (!m->pg_init_required)
1044 m->pg_init_in_progress = 0;
1045 queue_work(kmultipathd, &m->process_queued_ios);
1046 spin_unlock_irqrestore(&m->lock, flags);
1049 static void pg_init_done(struct dm_path *path, int errors)
1051 struct pgpath *pgpath = path_to_pgpath(path);
1052 struct priority_group *pg = pgpath->pg;
1053 struct multipath *m = pg->m;
1054 unsigned long flags;
1056 /* device or driver problems */
1061 if (!m->hw_handler_name) {
1065 DMERR("Cannot failover device because scsi_dh_%s was not "
1066 "loaded.", m->hw_handler_name);
1068 * Fail path for now, so we do not ping pong
1072 case SCSI_DH_DEV_TEMP_BUSY:
1074 * Probably doing something like FW upgrade on the
1075 * controller so try the other pg.
1077 bypass_pg(m, pg, 1);
1079 /* TODO: For SCSI_DH_RETRY we should wait a couple seconds */
1081 case SCSI_DH_IMM_RETRY:
1082 case SCSI_DH_RES_TEMP_UNAVAIL:
1083 if (pg_init_limit_reached(m, pgpath))
1089 * We probably do not want to fail the path for a device
1090 * error, but this is what the old dm did. In future
1091 * patches we can do more advanced handling.
1096 spin_lock_irqsave(&m->lock, flags);
1098 DMERR("Could not failover device. Error %d.", errors);
1099 m->current_pgpath = NULL;
1100 m->current_pg = NULL;
1101 } else if (!m->pg_init_required) {
1106 m->pg_init_in_progress = 0;
1107 queue_work(kmultipathd, &m->process_queued_ios);
1108 spin_unlock_irqrestore(&m->lock, flags);
1114 static int do_end_io(struct multipath *m, struct bio *bio,
1115 int error, struct dm_mpath_io *mpio)
1117 unsigned long flags;
1120 return 0; /* I/O complete */
1122 if ((error == -EWOULDBLOCK) && bio_rw_ahead(bio))
1125 if (error == -EOPNOTSUPP)
1128 spin_lock_irqsave(&m->lock, flags);
1129 if (!m->nr_valid_paths) {
1130 if (__must_push_back(m)) {
1131 spin_unlock_irqrestore(&m->lock, flags);
1132 return DM_ENDIO_REQUEUE;
1133 } else if (!m->queue_if_no_path) {
1134 spin_unlock_irqrestore(&m->lock, flags);
1137 spin_unlock_irqrestore(&m->lock, flags);
1141 spin_unlock_irqrestore(&m->lock, flags);
1144 fail_path(mpio->pgpath);
1147 dm_bio_restore(&mpio->details, bio);
1149 /* queue for the daemon to resubmit or fail */
1150 spin_lock_irqsave(&m->lock, flags);
1151 bio_list_add(&m->queued_ios, bio);
1154 queue_work(kmultipathd, &m->process_queued_ios);
1155 spin_unlock_irqrestore(&m->lock, flags);
1157 return DM_ENDIO_INCOMPLETE; /* io not complete */
1160 static int multipath_end_io(struct dm_target *ti, struct bio *bio,
1161 int error, union map_info *map_context)
1163 struct multipath *m = ti->private;
1164 struct dm_mpath_io *mpio = map_context->ptr;
1165 struct pgpath *pgpath = mpio->pgpath;
1166 struct path_selector *ps;
1169 r = do_end_io(m, bio, error, mpio);
1171 ps = &pgpath->pg->ps;
1172 if (ps->type->end_io)
1173 ps->type->end_io(ps, &pgpath->path);
1175 if (r != DM_ENDIO_INCOMPLETE)
1176 mempool_free(mpio, m->mpio_pool);
1182 * Suspend can't complete until all the I/O is processed so if
1183 * the last path fails we must error any remaining I/O.
1184 * Note that if the freeze_bdev fails while suspending, the
1185 * queue_if_no_path state is lost - userspace should reset it.
1187 static void multipath_presuspend(struct dm_target *ti)
1189 struct multipath *m = (struct multipath *) ti->private;
1191 queue_if_no_path(m, 0, 1);
1195 * Restore the queue_if_no_path setting.
1197 static void multipath_resume(struct dm_target *ti)
1199 struct multipath *m = (struct multipath *) ti->private;
1200 unsigned long flags;
1202 spin_lock_irqsave(&m->lock, flags);
1203 m->queue_if_no_path = m->saved_queue_if_no_path;
1204 spin_unlock_irqrestore(&m->lock, flags);
1208 * Info output has the following format:
1209 * num_multipath_feature_args [multipath_feature_args]*
1210 * num_handler_status_args [handler_status_args]*
1211 * num_groups init_group_number
1212 * [A|D|E num_ps_status_args [ps_status_args]*
1213 * num_paths num_selector_args
1214 * [path_dev A|F fail_count [selector_args]* ]+ ]+
1216 * Table output has the following format (identical to the constructor string):
1217 * num_feature_args [features_args]*
1218 * num_handler_args hw_handler [hw_handler_args]*
1219 * num_groups init_group_number
1220 * [priority selector-name num_ps_args [ps_args]*
1221 * num_paths num_selector_args [path_dev [selector_args]* ]+ ]+
1223 static int multipath_status(struct dm_target *ti, status_type_t type,
1224 char *result, unsigned int maxlen)
1227 unsigned long flags;
1228 struct multipath *m = (struct multipath *) ti->private;
1229 struct priority_group *pg;
1234 spin_lock_irqsave(&m->lock, flags);
1237 if (type == STATUSTYPE_INFO)
1238 DMEMIT("2 %u %u ", m->queue_size, m->pg_init_count);
1240 DMEMIT("%u ", m->queue_if_no_path +
1241 (m->pg_init_retries > 0) * 2);
1242 if (m->queue_if_no_path)
1243 DMEMIT("queue_if_no_path ");
1244 if (m->pg_init_retries)
1245 DMEMIT("pg_init_retries %u ", m->pg_init_retries);
1248 if (!m->hw_handler_name || type == STATUSTYPE_INFO)
1251 DMEMIT("1 %s ", m->hw_handler_name);
1253 DMEMIT("%u ", m->nr_priority_groups);
1256 pg_num = m->next_pg->pg_num;
1257 else if (m->current_pg)
1258 pg_num = m->current_pg->pg_num;
1262 DMEMIT("%u ", pg_num);
1265 case STATUSTYPE_INFO:
1266 list_for_each_entry(pg, &m->priority_groups, list) {
1268 state = 'D'; /* Disabled */
1269 else if (pg == m->current_pg)
1270 state = 'A'; /* Currently Active */
1272 state = 'E'; /* Enabled */
1274 DMEMIT("%c ", state);
1276 if (pg->ps.type->status)
1277 sz += pg->ps.type->status(&pg->ps, NULL, type,
1283 DMEMIT("%u %u ", pg->nr_pgpaths,
1284 pg->ps.type->info_args);
1286 list_for_each_entry(p, &pg->pgpaths, list) {
1287 DMEMIT("%s %s %u ", p->path.dev->name,
1288 p->path.is_active ? "A" : "F",
1290 if (pg->ps.type->status)
1291 sz += pg->ps.type->status(&pg->ps,
1292 &p->path, type, result + sz,
1298 case STATUSTYPE_TABLE:
1299 list_for_each_entry(pg, &m->priority_groups, list) {
1300 DMEMIT("%s ", pg->ps.type->name);
1302 if (pg->ps.type->status)
1303 sz += pg->ps.type->status(&pg->ps, NULL, type,
1309 DMEMIT("%u %u ", pg->nr_pgpaths,
1310 pg->ps.type->table_args);
1312 list_for_each_entry(p, &pg->pgpaths, list) {
1313 DMEMIT("%s ", p->path.dev->name);
1314 if (pg->ps.type->status)
1315 sz += pg->ps.type->status(&pg->ps,
1316 &p->path, type, result + sz,
1323 spin_unlock_irqrestore(&m->lock, flags);
1328 static int multipath_message(struct dm_target *ti, unsigned argc, char **argv)
1332 struct multipath *m = (struct multipath *) ti->private;
1336 if (!strnicmp(argv[0], MESG_STR("queue_if_no_path")))
1337 return queue_if_no_path(m, 1, 0);
1338 else if (!strnicmp(argv[0], MESG_STR("fail_if_no_path")))
1339 return queue_if_no_path(m, 0, 0);
1345 if (!strnicmp(argv[0], MESG_STR("disable_group")))
1346 return bypass_pg_num(m, argv[1], 1);
1347 else if (!strnicmp(argv[0], MESG_STR("enable_group")))
1348 return bypass_pg_num(m, argv[1], 0);
1349 else if (!strnicmp(argv[0], MESG_STR("switch_group")))
1350 return switch_pg_num(m, argv[1]);
1351 else if (!strnicmp(argv[0], MESG_STR("reinstate_path")))
1352 action = reinstate_path;
1353 else if (!strnicmp(argv[0], MESG_STR("fail_path")))
1358 r = dm_get_device(ti, argv[1], ti->begin, ti->len,
1359 dm_table_get_mode(ti->table), &dev);
1361 DMWARN("message: error getting device %s",
1366 r = action_dev(m, dev, action);
1368 dm_put_device(ti, dev);
1373 DMWARN("Unrecognised multipath message received.");
1377 static int multipath_ioctl(struct dm_target *ti, struct inode *inode,
1378 struct file *filp, unsigned int cmd,
1381 struct multipath *m = (struct multipath *) ti->private;
1382 struct block_device *bdev = NULL;
1383 unsigned long flags;
1384 struct file fake_file = {};
1385 struct dentry fake_dentry = {};
1388 fake_file.f_path.dentry = &fake_dentry;
1390 spin_lock_irqsave(&m->lock, flags);
1392 if (!m->current_pgpath)
1395 if (m->current_pgpath) {
1396 bdev = m->current_pgpath->path.dev->bdev;
1397 fake_dentry.d_inode = bdev->bd_inode;
1398 fake_file.f_mode = m->current_pgpath->path.dev->mode;
1406 spin_unlock_irqrestore(&m->lock, flags);
1408 return r ? : blkdev_driver_ioctl(bdev->bd_inode, &fake_file,
1409 bdev->bd_disk, cmd, arg);
1412 /*-----------------------------------------------------------------
1414 *---------------------------------------------------------------*/
1415 static struct target_type multipath_target = {
1416 .name = "multipath",
1417 .version = {1, 0, 5},
1418 .module = THIS_MODULE,
1419 .ctr = multipath_ctr,
1420 .dtr = multipath_dtr,
1421 .map = multipath_map,
1422 .end_io = multipath_end_io,
1423 .presuspend = multipath_presuspend,
1424 .resume = multipath_resume,
1425 .status = multipath_status,
1426 .message = multipath_message,
1427 .ioctl = multipath_ioctl,
1430 static int __init dm_multipath_init(void)
1434 /* allocate a slab for the dm_ios */
1435 _mpio_cache = KMEM_CACHE(dm_mpath_io, 0);
1439 r = dm_register_target(&multipath_target);
1441 DMERR("register failed %d", r);
1442 kmem_cache_destroy(_mpio_cache);
1446 kmultipathd = create_workqueue("kmpathd");
1448 DMERR("failed to create workqueue kmpathd");
1449 dm_unregister_target(&multipath_target);
1450 kmem_cache_destroy(_mpio_cache);
1454 DMINFO("version %u.%u.%u loaded",
1455 multipath_target.version[0], multipath_target.version[1],
1456 multipath_target.version[2]);
1461 static void __exit dm_multipath_exit(void)
1465 destroy_workqueue(kmultipathd);
1467 r = dm_unregister_target(&multipath_target);
1469 DMERR("target unregister failed %d", r);
1470 kmem_cache_destroy(_mpio_cache);
1473 EXPORT_SYMBOL_GPL(dm_pg_init_complete);
1475 module_init(dm_multipath_init);
1476 module_exit(dm_multipath_exit);
1478 MODULE_DESCRIPTION(DM_NAME " multipath target");
1479 MODULE_AUTHOR("Sistina Software <dm-devel@redhat.com>");
1480 MODULE_LICENSE("GPL");