Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * Copyright (C) 2003 Sistina Software Limited. | |
3 | * Copyright (C) 2004-2005 Red Hat, Inc. All rights reserved. | |
4 | * | |
5 | * This file is released under the GPL. | |
6 | */ | |
7 | ||
586e80e6 MP |
8 | #include <linux/device-mapper.h> |
9 | ||
1da177e4 | 10 | #include "dm-path-selector.h" |
b15546f9 | 11 | #include "dm-uevent.h" |
1da177e4 LT |
12 | |
13 | #include <linux/ctype.h> | |
14 | #include <linux/init.h> | |
15 | #include <linux/mempool.h> | |
16 | #include <linux/module.h> | |
17 | #include <linux/pagemap.h> | |
18 | #include <linux/slab.h> | |
19 | #include <linux/time.h> | |
20 | #include <linux/workqueue.h> | |
cfae5c9b | 21 | #include <scsi/scsi_dh.h> |
1da177e4 LT |
22 | #include <asm/atomic.h> |
23 | ||
72d94861 | 24 | #define DM_MSG_PREFIX "multipath" |
1da177e4 LT |
25 | #define MESG_STR(x) x, sizeof(x) |
26 | ||
27 | /* Path properties */ | |
28 | struct pgpath { | |
29 | struct list_head list; | |
30 | ||
31 | struct priority_group *pg; /* Owning PG */ | |
6680073d | 32 | unsigned is_active; /* Path status */ |
1da177e4 LT |
33 | unsigned fail_count; /* Cumulative failure count */ |
34 | ||
c922d5f7 | 35 | struct dm_path path; |
224cb3e9 | 36 | struct work_struct deactivate_path; |
e54f77dd | 37 | struct work_struct activate_path; |
1da177e4 LT |
38 | }; |
39 | ||
40 | #define path_to_pgpath(__pgp) container_of((__pgp), struct pgpath, path) | |
41 | ||
42 | /* | |
43 | * Paths are grouped into Priority Groups and numbered from 1 upwards. | |
44 | * Each has a path selector which controls which path gets used. | |
45 | */ | |
46 | struct priority_group { | |
47 | struct list_head list; | |
48 | ||
49 | struct multipath *m; /* Owning multipath instance */ | |
50 | struct path_selector ps; | |
51 | ||
52 | unsigned pg_num; /* Reference number */ | |
53 | unsigned bypassed; /* Temporarily bypass this PG? */ | |
54 | ||
55 | unsigned nr_pgpaths; /* Number of paths in PG */ | |
56 | struct list_head pgpaths; | |
57 | }; | |
58 | ||
59 | /* Multipath context */ | |
60 | struct multipath { | |
61 | struct list_head list; | |
62 | struct dm_target *ti; | |
63 | ||
64 | spinlock_t lock; | |
65 | ||
cfae5c9b | 66 | const char *hw_handler_name; |
1da177e4 LT |
67 | unsigned nr_priority_groups; |
68 | struct list_head priority_groups; | |
69 | unsigned pg_init_required; /* pg_init needs calling? */ | |
c3cd4f6b | 70 | unsigned pg_init_in_progress; /* Only one pg_init allowed at once */ |
1da177e4 LT |
71 | |
72 | unsigned nr_valid_paths; /* Total number of usable paths */ | |
73 | struct pgpath *current_pgpath; | |
74 | struct priority_group *current_pg; | |
75 | struct priority_group *next_pg; /* Switch to this PG if set */ | |
76 | unsigned repeat_count; /* I/Os left before calling PS again */ | |
77 | ||
78 | unsigned queue_io; /* Must we queue all I/O? */ | |
79 | unsigned queue_if_no_path; /* Queue I/O if last path fails? */ | |
436d4108 | 80 | unsigned saved_queue_if_no_path;/* Saved state during suspension */ |
c9e45581 DW |
81 | unsigned pg_init_retries; /* Number of times to retry pg_init */ |
82 | unsigned pg_init_count; /* Number of times pg_init called */ | |
1da177e4 LT |
83 | |
84 | struct work_struct process_queued_ios; | |
f40c67f0 | 85 | struct list_head queued_ios; |
1da177e4 LT |
86 | unsigned queue_size; |
87 | ||
88 | struct work_struct trigger_event; | |
89 | ||
90 | /* | |
028867ac | 91 | * We must use a mempool of dm_mpath_io structs so that we |
1da177e4 LT |
92 | * can resubmit bios on error. |
93 | */ | |
94 | mempool_t *mpio_pool; | |
95 | }; | |
96 | ||
97 | /* | |
98 | * Context information attached to each bio we process. | |
99 | */ | |
028867ac | 100 | struct dm_mpath_io { |
1da177e4 | 101 | struct pgpath *pgpath; |
02ab823f | 102 | size_t nr_bytes; |
1da177e4 LT |
103 | }; |
104 | ||
105 | typedef int (*action_fn) (struct pgpath *pgpath); | |
106 | ||
107 | #define MIN_IOS 256 /* Mempool size */ | |
108 | ||
e18b890b | 109 | static struct kmem_cache *_mpio_cache; |
1da177e4 | 110 | |
bab7cfc7 | 111 | static struct workqueue_struct *kmultipathd, *kmpath_handlerd; |
c4028958 DH |
112 | static void process_queued_ios(struct work_struct *work); |
113 | static void trigger_event(struct work_struct *work); | |
bab7cfc7 | 114 | static void activate_path(struct work_struct *work); |
224cb3e9 | 115 | static void deactivate_path(struct work_struct *work); |
1da177e4 LT |
116 | |
117 | ||
118 | /*----------------------------------------------- | |
119 | * Allocation routines | |
120 | *-----------------------------------------------*/ | |
121 | ||
122 | static struct pgpath *alloc_pgpath(void) | |
123 | { | |
e69fae56 | 124 | struct pgpath *pgpath = kzalloc(sizeof(*pgpath), GFP_KERNEL); |
1da177e4 | 125 | |
224cb3e9 | 126 | if (pgpath) { |
6680073d | 127 | pgpath->is_active = 1; |
224cb3e9 | 128 | INIT_WORK(&pgpath->deactivate_path, deactivate_path); |
e54f77dd | 129 | INIT_WORK(&pgpath->activate_path, activate_path); |
224cb3e9 | 130 | } |
1da177e4 LT |
131 | |
132 | return pgpath; | |
133 | } | |
134 | ||
028867ac | 135 | static void free_pgpath(struct pgpath *pgpath) |
1da177e4 LT |
136 | { |
137 | kfree(pgpath); | |
138 | } | |
139 | ||
224cb3e9 MA |
140 | static void deactivate_path(struct work_struct *work) |
141 | { | |
142 | struct pgpath *pgpath = | |
143 | container_of(work, struct pgpath, deactivate_path); | |
144 | ||
145 | blk_abort_queue(pgpath->path.dev->bdev->bd_disk->queue); | |
146 | } | |
147 | ||
1da177e4 LT |
148 | static struct priority_group *alloc_priority_group(void) |
149 | { | |
150 | struct priority_group *pg; | |
151 | ||
e69fae56 | 152 | pg = kzalloc(sizeof(*pg), GFP_KERNEL); |
1da177e4 | 153 | |
e69fae56 MM |
154 | if (pg) |
155 | INIT_LIST_HEAD(&pg->pgpaths); | |
1da177e4 LT |
156 | |
157 | return pg; | |
158 | } | |
159 | ||
160 | static void free_pgpaths(struct list_head *pgpaths, struct dm_target *ti) | |
161 | { | |
162 | struct pgpath *pgpath, *tmp; | |
ae11b1b3 | 163 | struct multipath *m = ti->private; |
1da177e4 LT |
164 | |
165 | list_for_each_entry_safe(pgpath, tmp, pgpaths, list) { | |
166 | list_del(&pgpath->list); | |
ae11b1b3 HR |
167 | if (m->hw_handler_name) |
168 | scsi_dh_detach(bdev_get_queue(pgpath->path.dev->bdev)); | |
1da177e4 LT |
169 | dm_put_device(ti, pgpath->path.dev); |
170 | free_pgpath(pgpath); | |
171 | } | |
172 | } | |
173 | ||
174 | static void free_priority_group(struct priority_group *pg, | |
175 | struct dm_target *ti) | |
176 | { | |
177 | struct path_selector *ps = &pg->ps; | |
178 | ||
179 | if (ps->type) { | |
180 | ps->type->destroy(ps); | |
181 | dm_put_path_selector(ps->type); | |
182 | } | |
183 | ||
184 | free_pgpaths(&pg->pgpaths, ti); | |
185 | kfree(pg); | |
186 | } | |
187 | ||
28f16c20 | 188 | static struct multipath *alloc_multipath(struct dm_target *ti) |
1da177e4 LT |
189 | { |
190 | struct multipath *m; | |
191 | ||
e69fae56 | 192 | m = kzalloc(sizeof(*m), GFP_KERNEL); |
1da177e4 | 193 | if (m) { |
1da177e4 | 194 | INIT_LIST_HEAD(&m->priority_groups); |
f40c67f0 | 195 | INIT_LIST_HEAD(&m->queued_ios); |
1da177e4 LT |
196 | spin_lock_init(&m->lock); |
197 | m->queue_io = 1; | |
c4028958 DH |
198 | INIT_WORK(&m->process_queued_ios, process_queued_ios); |
199 | INIT_WORK(&m->trigger_event, trigger_event); | |
93d2341c | 200 | m->mpio_pool = mempool_create_slab_pool(MIN_IOS, _mpio_cache); |
1da177e4 LT |
201 | if (!m->mpio_pool) { |
202 | kfree(m); | |
203 | return NULL; | |
204 | } | |
28f16c20 MM |
205 | m->ti = ti; |
206 | ti->private = m; | |
1da177e4 LT |
207 | } |
208 | ||
209 | return m; | |
210 | } | |
211 | ||
212 | static void free_multipath(struct multipath *m) | |
213 | { | |
214 | struct priority_group *pg, *tmp; | |
1da177e4 LT |
215 | |
216 | list_for_each_entry_safe(pg, tmp, &m->priority_groups, list) { | |
217 | list_del(&pg->list); | |
218 | free_priority_group(pg, m->ti); | |
219 | } | |
220 | ||
cfae5c9b | 221 | kfree(m->hw_handler_name); |
1da177e4 LT |
222 | mempool_destroy(m->mpio_pool); |
223 | kfree(m); | |
224 | } | |
225 | ||
226 | ||
227 | /*----------------------------------------------- | |
228 | * Path selection | |
229 | *-----------------------------------------------*/ | |
230 | ||
231 | static void __switch_pg(struct multipath *m, struct pgpath *pgpath) | |
232 | { | |
1da177e4 LT |
233 | m->current_pg = pgpath->pg; |
234 | ||
235 | /* Must we initialise the PG first, and queue I/O till it's ready? */ | |
cfae5c9b | 236 | if (m->hw_handler_name) { |
1da177e4 LT |
237 | m->pg_init_required = 1; |
238 | m->queue_io = 1; | |
239 | } else { | |
240 | m->pg_init_required = 0; | |
241 | m->queue_io = 0; | |
242 | } | |
c9e45581 DW |
243 | |
244 | m->pg_init_count = 0; | |
1da177e4 LT |
245 | } |
246 | ||
02ab823f KU |
247 | static int __choose_path_in_pg(struct multipath *m, struct priority_group *pg, |
248 | size_t nr_bytes) | |
1da177e4 | 249 | { |
c922d5f7 | 250 | struct dm_path *path; |
1da177e4 | 251 | |
02ab823f | 252 | path = pg->ps.type->select_path(&pg->ps, &m->repeat_count, nr_bytes); |
1da177e4 LT |
253 | if (!path) |
254 | return -ENXIO; | |
255 | ||
256 | m->current_pgpath = path_to_pgpath(path); | |
257 | ||
258 | if (m->current_pg != pg) | |
259 | __switch_pg(m, m->current_pgpath); | |
260 | ||
261 | return 0; | |
262 | } | |
263 | ||
02ab823f | 264 | static void __choose_pgpath(struct multipath *m, size_t nr_bytes) |
1da177e4 LT |
265 | { |
266 | struct priority_group *pg; | |
267 | unsigned bypassed = 1; | |
268 | ||
269 | if (!m->nr_valid_paths) | |
270 | goto failed; | |
271 | ||
272 | /* Were we instructed to switch PG? */ | |
273 | if (m->next_pg) { | |
274 | pg = m->next_pg; | |
275 | m->next_pg = NULL; | |
02ab823f | 276 | if (!__choose_path_in_pg(m, pg, nr_bytes)) |
1da177e4 LT |
277 | return; |
278 | } | |
279 | ||
280 | /* Don't change PG until it has no remaining paths */ | |
02ab823f | 281 | if (m->current_pg && !__choose_path_in_pg(m, m->current_pg, nr_bytes)) |
1da177e4 LT |
282 | return; |
283 | ||
284 | /* | |
285 | * Loop through priority groups until we find a valid path. | |
286 | * First time we skip PGs marked 'bypassed'. | |
287 | * Second time we only try the ones we skipped. | |
288 | */ | |
289 | do { | |
290 | list_for_each_entry(pg, &m->priority_groups, list) { | |
291 | if (pg->bypassed == bypassed) | |
292 | continue; | |
02ab823f | 293 | if (!__choose_path_in_pg(m, pg, nr_bytes)) |
1da177e4 LT |
294 | return; |
295 | } | |
296 | } while (bypassed--); | |
297 | ||
298 | failed: | |
299 | m->current_pgpath = NULL; | |
300 | m->current_pg = NULL; | |
301 | } | |
302 | ||
45e15720 KU |
303 | /* |
304 | * Check whether bios must be queued in the device-mapper core rather | |
305 | * than here in the target. | |
306 | * | |
307 | * m->lock must be held on entry. | |
308 | * | |
309 | * If m->queue_if_no_path and m->saved_queue_if_no_path hold the | |
310 | * same value then we are not between multipath_presuspend() | |
311 | * and multipath_resume() calls and we have no need to check | |
312 | * for the DMF_NOFLUSH_SUSPENDING flag. | |
313 | */ | |
314 | static int __must_push_back(struct multipath *m) | |
315 | { | |
316 | return (m->queue_if_no_path != m->saved_queue_if_no_path && | |
317 | dm_noflush_suspending(m->ti)); | |
318 | } | |
319 | ||
f40c67f0 | 320 | static int map_io(struct multipath *m, struct request *clone, |
028867ac | 321 | struct dm_mpath_io *mpio, unsigned was_queued) |
1da177e4 | 322 | { |
d2a7ad29 | 323 | int r = DM_MAPIO_REMAPPED; |
f40c67f0 | 324 | size_t nr_bytes = blk_rq_bytes(clone); |
1da177e4 LT |
325 | unsigned long flags; |
326 | struct pgpath *pgpath; | |
f40c67f0 | 327 | struct block_device *bdev; |
1da177e4 LT |
328 | |
329 | spin_lock_irqsave(&m->lock, flags); | |
330 | ||
331 | /* Do we need to select a new pgpath? */ | |
332 | if (!m->current_pgpath || | |
333 | (!m->queue_io && (m->repeat_count && --m->repeat_count == 0))) | |
02ab823f | 334 | __choose_pgpath(m, nr_bytes); |
1da177e4 LT |
335 | |
336 | pgpath = m->current_pgpath; | |
337 | ||
338 | if (was_queued) | |
339 | m->queue_size--; | |
340 | ||
341 | if ((pgpath && m->queue_io) || | |
436d4108 | 342 | (!pgpath && m->queue_if_no_path)) { |
1da177e4 | 343 | /* Queue for the daemon to resubmit */ |
f40c67f0 | 344 | list_add_tail(&clone->queuelist, &m->queued_ios); |
1da177e4 | 345 | m->queue_size++; |
c3cd4f6b AK |
346 | if ((m->pg_init_required && !m->pg_init_in_progress) || |
347 | !m->queue_io) | |
c557308e | 348 | queue_work(kmultipathd, &m->process_queued_ios); |
1da177e4 | 349 | pgpath = NULL; |
d2a7ad29 | 350 | r = DM_MAPIO_SUBMITTED; |
f40c67f0 KU |
351 | } else if (pgpath) { |
352 | bdev = pgpath->path.dev->bdev; | |
353 | clone->q = bdev_get_queue(bdev); | |
354 | clone->rq_disk = bdev->bd_disk; | |
355 | } else if (__must_push_back(m)) | |
45e15720 KU |
356 | r = DM_MAPIO_REQUEUE; |
357 | else | |
358 | r = -EIO; /* Failed */ | |
1da177e4 LT |
359 | |
360 | mpio->pgpath = pgpath; | |
02ab823f KU |
361 | mpio->nr_bytes = nr_bytes; |
362 | ||
363 | if (r == DM_MAPIO_REMAPPED && pgpath->pg->ps.type->start_io) | |
364 | pgpath->pg->ps.type->start_io(&pgpath->pg->ps, &pgpath->path, | |
365 | nr_bytes); | |
1da177e4 LT |
366 | |
367 | spin_unlock_irqrestore(&m->lock, flags); | |
368 | ||
369 | return r; | |
370 | } | |
371 | ||
372 | /* | |
373 | * If we run out of usable paths, should we queue I/O or error it? | |
374 | */ | |
485ef69e AK |
375 | static int queue_if_no_path(struct multipath *m, unsigned queue_if_no_path, |
376 | unsigned save_old_value) | |
1da177e4 LT |
377 | { |
378 | unsigned long flags; | |
379 | ||
380 | spin_lock_irqsave(&m->lock, flags); | |
381 | ||
485ef69e AK |
382 | if (save_old_value) |
383 | m->saved_queue_if_no_path = m->queue_if_no_path; | |
384 | else | |
385 | m->saved_queue_if_no_path = queue_if_no_path; | |
1da177e4 | 386 | m->queue_if_no_path = queue_if_no_path; |
c3cd4f6b | 387 | if (!m->queue_if_no_path && m->queue_size) |
c557308e | 388 | queue_work(kmultipathd, &m->process_queued_ios); |
1da177e4 LT |
389 | |
390 | spin_unlock_irqrestore(&m->lock, flags); | |
391 | ||
392 | return 0; | |
393 | } | |
394 | ||
395 | /*----------------------------------------------------------------- | |
396 | * The multipath daemon is responsible for resubmitting queued ios. | |
397 | *---------------------------------------------------------------*/ | |
398 | ||
399 | static void dispatch_queued_ios(struct multipath *m) | |
400 | { | |
401 | int r; | |
402 | unsigned long flags; | |
028867ac | 403 | struct dm_mpath_io *mpio; |
1da177e4 | 404 | union map_info *info; |
f40c67f0 KU |
405 | struct request *clone, *n; |
406 | LIST_HEAD(cl); | |
1da177e4 LT |
407 | |
408 | spin_lock_irqsave(&m->lock, flags); | |
f40c67f0 | 409 | list_splice_init(&m->queued_ios, &cl); |
1da177e4 LT |
410 | spin_unlock_irqrestore(&m->lock, flags); |
411 | ||
f40c67f0 KU |
412 | list_for_each_entry_safe(clone, n, &cl, queuelist) { |
413 | list_del_init(&clone->queuelist); | |
1da177e4 | 414 | |
f40c67f0 | 415 | info = dm_get_rq_mapinfo(clone); |
1da177e4 LT |
416 | mpio = info->ptr; |
417 | ||
f40c67f0 KU |
418 | r = map_io(m, clone, mpio, 1); |
419 | if (r < 0) { | |
420 | mempool_free(mpio, m->mpio_pool); | |
421 | dm_kill_unmapped_request(clone, r); | |
422 | } else if (r == DM_MAPIO_REMAPPED) | |
423 | dm_dispatch_request(clone); | |
424 | else if (r == DM_MAPIO_REQUEUE) { | |
425 | mempool_free(mpio, m->mpio_pool); | |
426 | dm_requeue_unmapped_request(clone); | |
427 | } | |
1da177e4 LT |
428 | } |
429 | } | |
430 | ||
c4028958 | 431 | static void process_queued_ios(struct work_struct *work) |
1da177e4 | 432 | { |
c4028958 DH |
433 | struct multipath *m = |
434 | container_of(work, struct multipath, process_queued_ios); | |
e54f77dd CS |
435 | struct pgpath *pgpath = NULL, *tmp; |
436 | unsigned must_queue = 1; | |
1da177e4 LT |
437 | unsigned long flags; |
438 | ||
439 | spin_lock_irqsave(&m->lock, flags); | |
440 | ||
c3cd4f6b AK |
441 | if (!m->queue_size) |
442 | goto out; | |
443 | ||
1da177e4 | 444 | if (!m->current_pgpath) |
02ab823f | 445 | __choose_pgpath(m, 0); |
1da177e4 LT |
446 | |
447 | pgpath = m->current_pgpath; | |
448 | ||
c3cd4f6b AK |
449 | if ((pgpath && !m->queue_io) || |
450 | (!pgpath && !m->queue_if_no_path)) | |
451 | must_queue = 0; | |
1da177e4 | 452 | |
b81aa1c7 | 453 | if (m->pg_init_required && !m->pg_init_in_progress && pgpath) { |
c9e45581 | 454 | m->pg_init_count++; |
1da177e4 | 455 | m->pg_init_required = 0; |
e54f77dd CS |
456 | list_for_each_entry(tmp, &pgpath->pg->pgpaths, list) { |
457 | if (queue_work(kmpath_handlerd, &tmp->activate_path)) | |
458 | m->pg_init_in_progress++; | |
459 | } | |
c3cd4f6b | 460 | } |
c3cd4f6b | 461 | out: |
1da177e4 | 462 | spin_unlock_irqrestore(&m->lock, flags); |
1da177e4 LT |
463 | if (!must_queue) |
464 | dispatch_queued_ios(m); | |
465 | } | |
466 | ||
467 | /* | |
468 | * An event is triggered whenever a path is taken out of use. | |
469 | * Includes path failure and PG bypass. | |
470 | */ | |
c4028958 | 471 | static void trigger_event(struct work_struct *work) |
1da177e4 | 472 | { |
c4028958 DH |
473 | struct multipath *m = |
474 | container_of(work, struct multipath, trigger_event); | |
1da177e4 LT |
475 | |
476 | dm_table_event(m->ti->table); | |
477 | } | |
478 | ||
479 | /*----------------------------------------------------------------- | |
480 | * Constructor/argument parsing: | |
481 | * <#multipath feature args> [<arg>]* | |
482 | * <#hw_handler args> [hw_handler [<arg>]*] | |
483 | * <#priority groups> | |
484 | * <initial priority group> | |
485 | * [<selector> <#selector args> [<arg>]* | |
486 | * <#paths> <#per-path selector args> | |
487 | * [<path> [<arg>]* ]+ ]+ | |
488 | *---------------------------------------------------------------*/ | |
489 | struct param { | |
490 | unsigned min; | |
491 | unsigned max; | |
492 | char *error; | |
493 | }; | |
494 | ||
1da177e4 LT |
495 | static int read_param(struct param *param, char *str, unsigned *v, char **error) |
496 | { | |
497 | if (!str || | |
498 | (sscanf(str, "%u", v) != 1) || | |
499 | (*v < param->min) || | |
500 | (*v > param->max)) { | |
501 | *error = param->error; | |
502 | return -EINVAL; | |
503 | } | |
504 | ||
505 | return 0; | |
506 | } | |
507 | ||
508 | struct arg_set { | |
509 | unsigned argc; | |
510 | char **argv; | |
511 | }; | |
512 | ||
513 | static char *shift(struct arg_set *as) | |
514 | { | |
515 | char *r; | |
516 | ||
517 | if (as->argc) { | |
518 | as->argc--; | |
519 | r = *as->argv; | |
520 | as->argv++; | |
521 | return r; | |
522 | } | |
523 | ||
524 | return NULL; | |
525 | } | |
526 | ||
527 | static void consume(struct arg_set *as, unsigned n) | |
528 | { | |
529 | BUG_ON (as->argc < n); | |
530 | as->argc -= n; | |
531 | as->argv += n; | |
532 | } | |
533 | ||
534 | static int parse_path_selector(struct arg_set *as, struct priority_group *pg, | |
535 | struct dm_target *ti) | |
536 | { | |
537 | int r; | |
538 | struct path_selector_type *pst; | |
539 | unsigned ps_argc; | |
540 | ||
541 | static struct param _params[] = { | |
72d94861 | 542 | {0, 1024, "invalid number of path selector args"}, |
1da177e4 LT |
543 | }; |
544 | ||
545 | pst = dm_get_path_selector(shift(as)); | |
546 | if (!pst) { | |
72d94861 | 547 | ti->error = "unknown path selector type"; |
1da177e4 LT |
548 | return -EINVAL; |
549 | } | |
550 | ||
551 | r = read_param(_params, shift(as), &ps_argc, &ti->error); | |
371b2e34 MP |
552 | if (r) { |
553 | dm_put_path_selector(pst); | |
1da177e4 | 554 | return -EINVAL; |
371b2e34 | 555 | } |
1da177e4 | 556 | |
0e0497c0 MP |
557 | if (ps_argc > as->argc) { |
558 | dm_put_path_selector(pst); | |
559 | ti->error = "not enough arguments for path selector"; | |
560 | return -EINVAL; | |
561 | } | |
562 | ||
1da177e4 LT |
563 | r = pst->create(&pg->ps, ps_argc, as->argv); |
564 | if (r) { | |
565 | dm_put_path_selector(pst); | |
72d94861 | 566 | ti->error = "path selector constructor failed"; |
1da177e4 LT |
567 | return r; |
568 | } | |
569 | ||
570 | pg->ps.type = pst; | |
571 | consume(as, ps_argc); | |
572 | ||
573 | return 0; | |
574 | } | |
575 | ||
576 | static struct pgpath *parse_path(struct arg_set *as, struct path_selector *ps, | |
577 | struct dm_target *ti) | |
578 | { | |
579 | int r; | |
580 | struct pgpath *p; | |
ae11b1b3 | 581 | struct multipath *m = ti->private; |
1da177e4 LT |
582 | |
583 | /* we need at least a path arg */ | |
584 | if (as->argc < 1) { | |
72d94861 | 585 | ti->error = "no device given"; |
01460f35 | 586 | return ERR_PTR(-EINVAL); |
1da177e4 LT |
587 | } |
588 | ||
589 | p = alloc_pgpath(); | |
590 | if (!p) | |
01460f35 | 591 | return ERR_PTR(-ENOMEM); |
1da177e4 LT |
592 | |
593 | r = dm_get_device(ti, shift(as), ti->begin, ti->len, | |
594 | dm_table_get_mode(ti->table), &p->path.dev); | |
595 | if (r) { | |
72d94861 | 596 | ti->error = "error getting device"; |
1da177e4 LT |
597 | goto bad; |
598 | } | |
599 | ||
ae11b1b3 | 600 | if (m->hw_handler_name) { |
a0cf7ea9 HR |
601 | struct request_queue *q = bdev_get_queue(p->path.dev->bdev); |
602 | ||
603 | r = scsi_dh_attach(q, m->hw_handler_name); | |
604 | if (r == -EBUSY) { | |
605 | /* | |
606 | * Already attached to different hw_handler, | |
607 | * try to reattach with correct one. | |
608 | */ | |
609 | scsi_dh_detach(q); | |
610 | r = scsi_dh_attach(q, m->hw_handler_name); | |
611 | } | |
612 | ||
ae11b1b3 | 613 | if (r < 0) { |
a0cf7ea9 | 614 | ti->error = "error attaching hardware handler"; |
ae11b1b3 HR |
615 | dm_put_device(ti, p->path.dev); |
616 | goto bad; | |
617 | } | |
618 | } | |
619 | ||
1da177e4 LT |
620 | r = ps->type->add_path(ps, &p->path, as->argc, as->argv, &ti->error); |
621 | if (r) { | |
622 | dm_put_device(ti, p->path.dev); | |
623 | goto bad; | |
624 | } | |
625 | ||
626 | return p; | |
627 | ||
628 | bad: | |
629 | free_pgpath(p); | |
01460f35 | 630 | return ERR_PTR(r); |
1da177e4 LT |
631 | } |
632 | ||
633 | static struct priority_group *parse_priority_group(struct arg_set *as, | |
28f16c20 | 634 | struct multipath *m) |
1da177e4 LT |
635 | { |
636 | static struct param _params[] = { | |
72d94861 AK |
637 | {1, 1024, "invalid number of paths"}, |
638 | {0, 1024, "invalid number of selector args"} | |
1da177e4 LT |
639 | }; |
640 | ||
641 | int r; | |
642 | unsigned i, nr_selector_args, nr_params; | |
643 | struct priority_group *pg; | |
28f16c20 | 644 | struct dm_target *ti = m->ti; |
1da177e4 LT |
645 | |
646 | if (as->argc < 2) { | |
647 | as->argc = 0; | |
01460f35 BM |
648 | ti->error = "not enough priority group arguments"; |
649 | return ERR_PTR(-EINVAL); | |
1da177e4 LT |
650 | } |
651 | ||
652 | pg = alloc_priority_group(); | |
653 | if (!pg) { | |
72d94861 | 654 | ti->error = "couldn't allocate priority group"; |
01460f35 | 655 | return ERR_PTR(-ENOMEM); |
1da177e4 LT |
656 | } |
657 | pg->m = m; | |
658 | ||
659 | r = parse_path_selector(as, pg, ti); | |
660 | if (r) | |
661 | goto bad; | |
662 | ||
663 | /* | |
664 | * read the paths | |
665 | */ | |
666 | r = read_param(_params, shift(as), &pg->nr_pgpaths, &ti->error); | |
667 | if (r) | |
668 | goto bad; | |
669 | ||
670 | r = read_param(_params + 1, shift(as), &nr_selector_args, &ti->error); | |
671 | if (r) | |
672 | goto bad; | |
673 | ||
674 | nr_params = 1 + nr_selector_args; | |
675 | for (i = 0; i < pg->nr_pgpaths; i++) { | |
676 | struct pgpath *pgpath; | |
677 | struct arg_set path_args; | |
678 | ||
148acff6 MP |
679 | if (as->argc < nr_params) { |
680 | ti->error = "not enough path parameters"; | |
1da177e4 | 681 | goto bad; |
148acff6 | 682 | } |
1da177e4 LT |
683 | |
684 | path_args.argc = nr_params; | |
685 | path_args.argv = as->argv; | |
686 | ||
687 | pgpath = parse_path(&path_args, &pg->ps, ti); | |
01460f35 BM |
688 | if (IS_ERR(pgpath)) { |
689 | r = PTR_ERR(pgpath); | |
1da177e4 | 690 | goto bad; |
01460f35 | 691 | } |
1da177e4 LT |
692 | |
693 | pgpath->pg = pg; | |
694 | list_add_tail(&pgpath->list, &pg->pgpaths); | |
695 | consume(as, nr_params); | |
696 | } | |
697 | ||
698 | return pg; | |
699 | ||
700 | bad: | |
701 | free_priority_group(pg, ti); | |
01460f35 | 702 | return ERR_PTR(r); |
1da177e4 LT |
703 | } |
704 | ||
28f16c20 | 705 | static int parse_hw_handler(struct arg_set *as, struct multipath *m) |
1da177e4 | 706 | { |
1da177e4 | 707 | unsigned hw_argc; |
28f16c20 | 708 | struct dm_target *ti = m->ti; |
1da177e4 LT |
709 | |
710 | static struct param _params[] = { | |
72d94861 | 711 | {0, 1024, "invalid number of hardware handler args"}, |
1da177e4 LT |
712 | }; |
713 | ||
cfae5c9b | 714 | if (read_param(_params, shift(as), &hw_argc, &ti->error)) |
1da177e4 LT |
715 | return -EINVAL; |
716 | ||
717 | if (!hw_argc) | |
718 | return 0; | |
719 | ||
e094f4f1 MP |
720 | if (hw_argc > as->argc) { |
721 | ti->error = "not enough arguments for hardware handler"; | |
722 | return -EINVAL; | |
723 | } | |
724 | ||
cfae5c9b CS |
725 | m->hw_handler_name = kstrdup(shift(as), GFP_KERNEL); |
726 | request_module("scsi_dh_%s", m->hw_handler_name); | |
727 | if (scsi_dh_handler_exist(m->hw_handler_name) == 0) { | |
72d94861 | 728 | ti->error = "unknown hardware handler type"; |
fe9233fb CS |
729 | kfree(m->hw_handler_name); |
730 | m->hw_handler_name = NULL; | |
1da177e4 LT |
731 | return -EINVAL; |
732 | } | |
14e98c5c CS |
733 | |
734 | if (hw_argc > 1) | |
735 | DMWARN("Ignoring user-specified arguments for " | |
736 | "hardware handler \"%s\"", m->hw_handler_name); | |
1da177e4 LT |
737 | consume(as, hw_argc - 1); |
738 | ||
739 | return 0; | |
740 | } | |
741 | ||
28f16c20 | 742 | static int parse_features(struct arg_set *as, struct multipath *m) |
1da177e4 LT |
743 | { |
744 | int r; | |
745 | unsigned argc; | |
28f16c20 | 746 | struct dm_target *ti = m->ti; |
c9e45581 | 747 | const char *param_name; |
1da177e4 LT |
748 | |
749 | static struct param _params[] = { | |
c9e45581 DW |
750 | {0, 3, "invalid number of feature args"}, |
751 | {1, 50, "pg_init_retries must be between 1 and 50"}, | |
1da177e4 LT |
752 | }; |
753 | ||
754 | r = read_param(_params, shift(as), &argc, &ti->error); | |
755 | if (r) | |
756 | return -EINVAL; | |
757 | ||
758 | if (!argc) | |
759 | return 0; | |
760 | ||
c9e45581 DW |
761 | do { |
762 | param_name = shift(as); | |
763 | argc--; | |
764 | ||
765 | if (!strnicmp(param_name, MESG_STR("queue_if_no_path"))) { | |
766 | r = queue_if_no_path(m, 1, 0); | |
767 | continue; | |
768 | } | |
769 | ||
770 | if (!strnicmp(param_name, MESG_STR("pg_init_retries")) && | |
771 | (argc >= 1)) { | |
772 | r = read_param(_params + 1, shift(as), | |
773 | &m->pg_init_retries, &ti->error); | |
774 | argc--; | |
775 | continue; | |
776 | } | |
777 | ||
1da177e4 | 778 | ti->error = "Unrecognised multipath feature request"; |
c9e45581 DW |
779 | r = -EINVAL; |
780 | } while (argc && !r); | |
781 | ||
782 | return r; | |
1da177e4 LT |
783 | } |
784 | ||
785 | static int multipath_ctr(struct dm_target *ti, unsigned int argc, | |
786 | char **argv) | |
787 | { | |
788 | /* target parameters */ | |
789 | static struct param _params[] = { | |
72d94861 AK |
790 | {1, 1024, "invalid number of priority groups"}, |
791 | {1, 1024, "invalid initial priority group number"}, | |
1da177e4 LT |
792 | }; |
793 | ||
794 | int r; | |
795 | struct multipath *m; | |
796 | struct arg_set as; | |
797 | unsigned pg_count = 0; | |
798 | unsigned next_pg_num; | |
799 | ||
800 | as.argc = argc; | |
801 | as.argv = argv; | |
802 | ||
28f16c20 | 803 | m = alloc_multipath(ti); |
1da177e4 | 804 | if (!m) { |
72d94861 | 805 | ti->error = "can't allocate multipath"; |
1da177e4 LT |
806 | return -EINVAL; |
807 | } | |
808 | ||
28f16c20 | 809 | r = parse_features(&as, m); |
1da177e4 LT |
810 | if (r) |
811 | goto bad; | |
812 | ||
28f16c20 | 813 | r = parse_hw_handler(&as, m); |
1da177e4 LT |
814 | if (r) |
815 | goto bad; | |
816 | ||
817 | r = read_param(_params, shift(&as), &m->nr_priority_groups, &ti->error); | |
818 | if (r) | |
819 | goto bad; | |
820 | ||
821 | r = read_param(_params + 1, shift(&as), &next_pg_num, &ti->error); | |
822 | if (r) | |
823 | goto bad; | |
824 | ||
825 | /* parse the priority groups */ | |
826 | while (as.argc) { | |
827 | struct priority_group *pg; | |
828 | ||
28f16c20 | 829 | pg = parse_priority_group(&as, m); |
01460f35 BM |
830 | if (IS_ERR(pg)) { |
831 | r = PTR_ERR(pg); | |
1da177e4 LT |
832 | goto bad; |
833 | } | |
834 | ||
835 | m->nr_valid_paths += pg->nr_pgpaths; | |
836 | list_add_tail(&pg->list, &m->priority_groups); | |
837 | pg_count++; | |
838 | pg->pg_num = pg_count; | |
839 | if (!--next_pg_num) | |
840 | m->next_pg = pg; | |
841 | } | |
842 | ||
843 | if (pg_count != m->nr_priority_groups) { | |
72d94861 | 844 | ti->error = "priority group count mismatch"; |
1da177e4 LT |
845 | r = -EINVAL; |
846 | goto bad; | |
847 | } | |
848 | ||
8627921f MP |
849 | ti->num_flush_requests = 1; |
850 | ||
1da177e4 LT |
851 | return 0; |
852 | ||
853 | bad: | |
854 | free_multipath(m); | |
855 | return r; | |
856 | } | |
857 | ||
858 | static void multipath_dtr(struct dm_target *ti) | |
859 | { | |
860 | struct multipath *m = (struct multipath *) ti->private; | |
a044d016 | 861 | |
bab7cfc7 | 862 | flush_workqueue(kmpath_handlerd); |
a044d016 | 863 | flush_workqueue(kmultipathd); |
53b351f9 | 864 | flush_scheduled_work(); |
1da177e4 LT |
865 | free_multipath(m); |
866 | } | |
867 | ||
868 | /* | |
f40c67f0 | 869 | * Map cloned requests |
1da177e4 | 870 | */ |
f40c67f0 | 871 | static int multipath_map(struct dm_target *ti, struct request *clone, |
1da177e4 LT |
872 | union map_info *map_context) |
873 | { | |
874 | int r; | |
028867ac | 875 | struct dm_mpath_io *mpio; |
1da177e4 LT |
876 | struct multipath *m = (struct multipath *) ti->private; |
877 | ||
f40c67f0 KU |
878 | mpio = mempool_alloc(m->mpio_pool, GFP_ATOMIC); |
879 | if (!mpio) | |
880 | /* ENOMEM, requeue */ | |
881 | return DM_MAPIO_REQUEUE; | |
882 | memset(mpio, 0, sizeof(*mpio)); | |
1da177e4 LT |
883 | |
884 | map_context->ptr = mpio; | |
f40c67f0 KU |
885 | clone->cmd_flags |= REQ_FAILFAST_TRANSPORT; |
886 | r = map_io(m, clone, mpio, 0); | |
45e15720 | 887 | if (r < 0 || r == DM_MAPIO_REQUEUE) |
1da177e4 LT |
888 | mempool_free(mpio, m->mpio_pool); |
889 | ||
890 | return r; | |
891 | } | |
892 | ||
893 | /* | |
894 | * Take a path out of use. | |
895 | */ | |
896 | static int fail_path(struct pgpath *pgpath) | |
897 | { | |
898 | unsigned long flags; | |
899 | struct multipath *m = pgpath->pg->m; | |
900 | ||
901 | spin_lock_irqsave(&m->lock, flags); | |
902 | ||
6680073d | 903 | if (!pgpath->is_active) |
1da177e4 LT |
904 | goto out; |
905 | ||
72d94861 | 906 | DMWARN("Failing path %s.", pgpath->path.dev->name); |
1da177e4 LT |
907 | |
908 | pgpath->pg->ps.type->fail_path(&pgpath->pg->ps, &pgpath->path); | |
6680073d | 909 | pgpath->is_active = 0; |
1da177e4 LT |
910 | pgpath->fail_count++; |
911 | ||
912 | m->nr_valid_paths--; | |
913 | ||
914 | if (pgpath == m->current_pgpath) | |
915 | m->current_pgpath = NULL; | |
916 | ||
b15546f9 MA |
917 | dm_path_uevent(DM_UEVENT_PATH_FAILED, m->ti, |
918 | pgpath->path.dev->name, m->nr_valid_paths); | |
919 | ||
fe9cf30e | 920 | schedule_work(&m->trigger_event); |
224cb3e9 | 921 | queue_work(kmultipathd, &pgpath->deactivate_path); |
1da177e4 LT |
922 | |
923 | out: | |
924 | spin_unlock_irqrestore(&m->lock, flags); | |
925 | ||
926 | return 0; | |
927 | } | |
928 | ||
929 | /* | |
930 | * Reinstate a previously-failed path | |
931 | */ | |
932 | static int reinstate_path(struct pgpath *pgpath) | |
933 | { | |
934 | int r = 0; | |
935 | unsigned long flags; | |
936 | struct multipath *m = pgpath->pg->m; | |
937 | ||
938 | spin_lock_irqsave(&m->lock, flags); | |
939 | ||
6680073d | 940 | if (pgpath->is_active) |
1da177e4 LT |
941 | goto out; |
942 | ||
def052d2 | 943 | if (!pgpath->pg->ps.type->reinstate_path) { |
1da177e4 LT |
944 | DMWARN("Reinstate path not supported by path selector %s", |
945 | pgpath->pg->ps.type->name); | |
946 | r = -EINVAL; | |
947 | goto out; | |
948 | } | |
949 | ||
950 | r = pgpath->pg->ps.type->reinstate_path(&pgpath->pg->ps, &pgpath->path); | |
951 | if (r) | |
952 | goto out; | |
953 | ||
6680073d | 954 | pgpath->is_active = 1; |
1da177e4 | 955 | |
e54f77dd CS |
956 | if (!m->nr_valid_paths++ && m->queue_size) { |
957 | m->current_pgpath = NULL; | |
c557308e | 958 | queue_work(kmultipathd, &m->process_queued_ios); |
e54f77dd CS |
959 | } else if (m->hw_handler_name && (m->current_pg == pgpath->pg)) { |
960 | if (queue_work(kmpath_handlerd, &pgpath->activate_path)) | |
961 | m->pg_init_in_progress++; | |
962 | } | |
1da177e4 | 963 | |
b15546f9 MA |
964 | dm_path_uevent(DM_UEVENT_PATH_REINSTATED, m->ti, |
965 | pgpath->path.dev->name, m->nr_valid_paths); | |
966 | ||
fe9cf30e | 967 | schedule_work(&m->trigger_event); |
1da177e4 LT |
968 | |
969 | out: | |
970 | spin_unlock_irqrestore(&m->lock, flags); | |
971 | ||
972 | return r; | |
973 | } | |
974 | ||
975 | /* | |
976 | * Fail or reinstate all paths that match the provided struct dm_dev. | |
977 | */ | |
978 | static int action_dev(struct multipath *m, struct dm_dev *dev, | |
979 | action_fn action) | |
980 | { | |
981 | int r = 0; | |
982 | struct pgpath *pgpath; | |
983 | struct priority_group *pg; | |
984 | ||
985 | list_for_each_entry(pg, &m->priority_groups, list) { | |
986 | list_for_each_entry(pgpath, &pg->pgpaths, list) { | |
987 | if (pgpath->path.dev == dev) | |
988 | r = action(pgpath); | |
989 | } | |
990 | } | |
991 | ||
992 | return r; | |
993 | } | |
994 | ||
995 | /* | |
996 | * Temporarily try to avoid having to use the specified PG | |
997 | */ | |
998 | static void bypass_pg(struct multipath *m, struct priority_group *pg, | |
999 | int bypassed) | |
1000 | { | |
1001 | unsigned long flags; | |
1002 | ||
1003 | spin_lock_irqsave(&m->lock, flags); | |
1004 | ||
1005 | pg->bypassed = bypassed; | |
1006 | m->current_pgpath = NULL; | |
1007 | m->current_pg = NULL; | |
1008 | ||
1009 | spin_unlock_irqrestore(&m->lock, flags); | |
1010 | ||
fe9cf30e | 1011 | schedule_work(&m->trigger_event); |
1da177e4 LT |
1012 | } |
1013 | ||
1014 | /* | |
1015 | * Switch to using the specified PG from the next I/O that gets mapped | |
1016 | */ | |
1017 | static int switch_pg_num(struct multipath *m, const char *pgstr) | |
1018 | { | |
1019 | struct priority_group *pg; | |
1020 | unsigned pgnum; | |
1021 | unsigned long flags; | |
1022 | ||
1023 | if (!pgstr || (sscanf(pgstr, "%u", &pgnum) != 1) || !pgnum || | |
1024 | (pgnum > m->nr_priority_groups)) { | |
1025 | DMWARN("invalid PG number supplied to switch_pg_num"); | |
1026 | return -EINVAL; | |
1027 | } | |
1028 | ||
1029 | spin_lock_irqsave(&m->lock, flags); | |
1030 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1031 | pg->bypassed = 0; | |
1032 | if (--pgnum) | |
1033 | continue; | |
1034 | ||
1035 | m->current_pgpath = NULL; | |
1036 | m->current_pg = NULL; | |
1037 | m->next_pg = pg; | |
1038 | } | |
1039 | spin_unlock_irqrestore(&m->lock, flags); | |
1040 | ||
fe9cf30e | 1041 | schedule_work(&m->trigger_event); |
1da177e4 LT |
1042 | return 0; |
1043 | } | |
1044 | ||
1045 | /* | |
1046 | * Set/clear bypassed status of a PG. | |
1047 | * PGs are numbered upwards from 1 in the order they were declared. | |
1048 | */ | |
1049 | static int bypass_pg_num(struct multipath *m, const char *pgstr, int bypassed) | |
1050 | { | |
1051 | struct priority_group *pg; | |
1052 | unsigned pgnum; | |
1053 | ||
1054 | if (!pgstr || (sscanf(pgstr, "%u", &pgnum) != 1) || !pgnum || | |
1055 | (pgnum > m->nr_priority_groups)) { | |
1056 | DMWARN("invalid PG number supplied to bypass_pg"); | |
1057 | return -EINVAL; | |
1058 | } | |
1059 | ||
1060 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1061 | if (!--pgnum) | |
1062 | break; | |
1063 | } | |
1064 | ||
1065 | bypass_pg(m, pg, bypassed); | |
1066 | return 0; | |
1067 | } | |
1068 | ||
c9e45581 DW |
1069 | /* |
1070 | * Should we retry pg_init immediately? | |
1071 | */ | |
1072 | static int pg_init_limit_reached(struct multipath *m, struct pgpath *pgpath) | |
1073 | { | |
1074 | unsigned long flags; | |
1075 | int limit_reached = 0; | |
1076 | ||
1077 | spin_lock_irqsave(&m->lock, flags); | |
1078 | ||
1079 | if (m->pg_init_count <= m->pg_init_retries) | |
1080 | m->pg_init_required = 1; | |
1081 | else | |
1082 | limit_reached = 1; | |
1083 | ||
1084 | spin_unlock_irqrestore(&m->lock, flags); | |
1085 | ||
1086 | return limit_reached; | |
1087 | } | |
1088 | ||
cfae5c9b CS |
1089 | static void pg_init_done(struct dm_path *path, int errors) |
1090 | { | |
1091 | struct pgpath *pgpath = path_to_pgpath(path); | |
1092 | struct priority_group *pg = pgpath->pg; | |
1093 | struct multipath *m = pg->m; | |
1094 | unsigned long flags; | |
1095 | ||
1096 | /* device or driver problems */ | |
1097 | switch (errors) { | |
1098 | case SCSI_DH_OK: | |
1099 | break; | |
1100 | case SCSI_DH_NOSYS: | |
1101 | if (!m->hw_handler_name) { | |
1102 | errors = 0; | |
1103 | break; | |
1104 | } | |
1105 | DMERR("Cannot failover device because scsi_dh_%s was not " | |
1106 | "loaded.", m->hw_handler_name); | |
1107 | /* | |
1108 | * Fail path for now, so we do not ping pong | |
1109 | */ | |
1110 | fail_path(pgpath); | |
1111 | break; | |
1112 | case SCSI_DH_DEV_TEMP_BUSY: | |
1113 | /* | |
1114 | * Probably doing something like FW upgrade on the | |
1115 | * controller so try the other pg. | |
1116 | */ | |
1117 | bypass_pg(m, pg, 1); | |
1118 | break; | |
1119 | /* TODO: For SCSI_DH_RETRY we should wait a couple seconds */ | |
1120 | case SCSI_DH_RETRY: | |
1121 | case SCSI_DH_IMM_RETRY: | |
1122 | case SCSI_DH_RES_TEMP_UNAVAIL: | |
1123 | if (pg_init_limit_reached(m, pgpath)) | |
1124 | fail_path(pgpath); | |
1125 | errors = 0; | |
1126 | break; | |
1127 | default: | |
1128 | /* | |
1129 | * We probably do not want to fail the path for a device | |
1130 | * error, but this is what the old dm did. In future | |
1131 | * patches we can do more advanced handling. | |
1132 | */ | |
1133 | fail_path(pgpath); | |
1134 | } | |
1135 | ||
1136 | spin_lock_irqsave(&m->lock, flags); | |
1137 | if (errors) { | |
e54f77dd CS |
1138 | if (pgpath == m->current_pgpath) { |
1139 | DMERR("Could not failover device. Error %d.", errors); | |
1140 | m->current_pgpath = NULL; | |
1141 | m->current_pg = NULL; | |
1142 | } | |
cfae5c9b CS |
1143 | } else if (!m->pg_init_required) { |
1144 | m->queue_io = 0; | |
1145 | pg->bypassed = 0; | |
1146 | } | |
1147 | ||
e54f77dd CS |
1148 | m->pg_init_in_progress--; |
1149 | if (!m->pg_init_in_progress) | |
1150 | queue_work(kmultipathd, &m->process_queued_ios); | |
cfae5c9b CS |
1151 | spin_unlock_irqrestore(&m->lock, flags); |
1152 | } | |
1153 | ||
bab7cfc7 CS |
1154 | static void activate_path(struct work_struct *work) |
1155 | { | |
1156 | int ret; | |
e54f77dd CS |
1157 | struct pgpath *pgpath = |
1158 | container_of(work, struct pgpath, activate_path); | |
bab7cfc7 | 1159 | |
e54f77dd CS |
1160 | ret = scsi_dh_activate(bdev_get_queue(pgpath->path.dev->bdev)); |
1161 | pg_init_done(&pgpath->path, ret); | |
bab7cfc7 CS |
1162 | } |
1163 | ||
1da177e4 LT |
1164 | /* |
1165 | * end_io handling | |
1166 | */ | |
f40c67f0 | 1167 | static int do_end_io(struct multipath *m, struct request *clone, |
028867ac | 1168 | int error, struct dm_mpath_io *mpio) |
1da177e4 | 1169 | { |
f40c67f0 KU |
1170 | /* |
1171 | * We don't queue any clone request inside the multipath target | |
1172 | * during end I/O handling, since those clone requests don't have | |
1173 | * bio clones. If we queue them inside the multipath target, | |
1174 | * we need to make bio clones, that requires memory allocation. | |
1175 | * (See drivers/md/dm.c:end_clone_bio() about why the clone requests | |
1176 | * don't have bio clones.) | |
1177 | * Instead of queueing the clone request here, we queue the original | |
1178 | * request into dm core, which will remake a clone request and | |
1179 | * clone bios for it and resubmit it later. | |
1180 | */ | |
1181 | int r = DM_ENDIO_REQUEUE; | |
640eb3b0 | 1182 | unsigned long flags; |
1da177e4 | 1183 | |
f40c67f0 | 1184 | if (!error && !clone->errors) |
1da177e4 LT |
1185 | return 0; /* I/O complete */ |
1186 | ||
f6a80ea8 AK |
1187 | if (error == -EOPNOTSUPP) |
1188 | return error; | |
1189 | ||
cfae5c9b CS |
1190 | if (mpio->pgpath) |
1191 | fail_path(mpio->pgpath); | |
1da177e4 | 1192 | |
640eb3b0 | 1193 | spin_lock_irqsave(&m->lock, flags); |
f40c67f0 KU |
1194 | if (!m->nr_valid_paths && !m->queue_if_no_path && !__must_push_back(m)) |
1195 | r = -EIO; | |
640eb3b0 | 1196 | spin_unlock_irqrestore(&m->lock, flags); |
1da177e4 | 1197 | |
f40c67f0 | 1198 | return r; |
1da177e4 LT |
1199 | } |
1200 | ||
f40c67f0 | 1201 | static int multipath_end_io(struct dm_target *ti, struct request *clone, |
1da177e4 LT |
1202 | int error, union map_info *map_context) |
1203 | { | |
028867ac AK |
1204 | struct multipath *m = ti->private; |
1205 | struct dm_mpath_io *mpio = map_context->ptr; | |
1da177e4 LT |
1206 | struct pgpath *pgpath = mpio->pgpath; |
1207 | struct path_selector *ps; | |
1208 | int r; | |
1209 | ||
f40c67f0 | 1210 | r = do_end_io(m, clone, error, mpio); |
1da177e4 LT |
1211 | if (pgpath) { |
1212 | ps = &pgpath->pg->ps; | |
1213 | if (ps->type->end_io) | |
02ab823f | 1214 | ps->type->end_io(ps, &pgpath->path, mpio->nr_bytes); |
1da177e4 | 1215 | } |
f40c67f0 | 1216 | mempool_free(mpio, m->mpio_pool); |
1da177e4 LT |
1217 | |
1218 | return r; | |
1219 | } | |
1220 | ||
1221 | /* | |
1222 | * Suspend can't complete until all the I/O is processed so if | |
436d4108 AK |
1223 | * the last path fails we must error any remaining I/O. |
1224 | * Note that if the freeze_bdev fails while suspending, the | |
1225 | * queue_if_no_path state is lost - userspace should reset it. | |
1da177e4 LT |
1226 | */ |
1227 | static void multipath_presuspend(struct dm_target *ti) | |
1228 | { | |
1229 | struct multipath *m = (struct multipath *) ti->private; | |
1da177e4 | 1230 | |
485ef69e | 1231 | queue_if_no_path(m, 0, 1); |
1da177e4 LT |
1232 | } |
1233 | ||
436d4108 AK |
1234 | /* |
1235 | * Restore the queue_if_no_path setting. | |
1236 | */ | |
1da177e4 LT |
1237 | static void multipath_resume(struct dm_target *ti) |
1238 | { | |
1239 | struct multipath *m = (struct multipath *) ti->private; | |
1240 | unsigned long flags; | |
1241 | ||
1242 | spin_lock_irqsave(&m->lock, flags); | |
436d4108 | 1243 | m->queue_if_no_path = m->saved_queue_if_no_path; |
1da177e4 LT |
1244 | spin_unlock_irqrestore(&m->lock, flags); |
1245 | } | |
1246 | ||
1247 | /* | |
1248 | * Info output has the following format: | |
1249 | * num_multipath_feature_args [multipath_feature_args]* | |
1250 | * num_handler_status_args [handler_status_args]* | |
1251 | * num_groups init_group_number | |
1252 | * [A|D|E num_ps_status_args [ps_status_args]* | |
1253 | * num_paths num_selector_args | |
1254 | * [path_dev A|F fail_count [selector_args]* ]+ ]+ | |
1255 | * | |
1256 | * Table output has the following format (identical to the constructor string): | |
1257 | * num_feature_args [features_args]* | |
1258 | * num_handler_args hw_handler [hw_handler_args]* | |
1259 | * num_groups init_group_number | |
1260 | * [priority selector-name num_ps_args [ps_args]* | |
1261 | * num_paths num_selector_args [path_dev [selector_args]* ]+ ]+ | |
1262 | */ | |
1263 | static int multipath_status(struct dm_target *ti, status_type_t type, | |
1264 | char *result, unsigned int maxlen) | |
1265 | { | |
1266 | int sz = 0; | |
1267 | unsigned long flags; | |
1268 | struct multipath *m = (struct multipath *) ti->private; | |
1da177e4 LT |
1269 | struct priority_group *pg; |
1270 | struct pgpath *p; | |
1271 | unsigned pg_num; | |
1272 | char state; | |
1273 | ||
1274 | spin_lock_irqsave(&m->lock, flags); | |
1275 | ||
1276 | /* Features */ | |
1277 | if (type == STATUSTYPE_INFO) | |
c9e45581 DW |
1278 | DMEMIT("2 %u %u ", m->queue_size, m->pg_init_count); |
1279 | else { | |
1280 | DMEMIT("%u ", m->queue_if_no_path + | |
1281 | (m->pg_init_retries > 0) * 2); | |
1282 | if (m->queue_if_no_path) | |
1283 | DMEMIT("queue_if_no_path "); | |
1284 | if (m->pg_init_retries) | |
1285 | DMEMIT("pg_init_retries %u ", m->pg_init_retries); | |
1286 | } | |
1da177e4 | 1287 | |
cfae5c9b | 1288 | if (!m->hw_handler_name || type == STATUSTYPE_INFO) |
1da177e4 LT |
1289 | DMEMIT("0 "); |
1290 | else | |
cfae5c9b | 1291 | DMEMIT("1 %s ", m->hw_handler_name); |
1da177e4 LT |
1292 | |
1293 | DMEMIT("%u ", m->nr_priority_groups); | |
1294 | ||
1295 | if (m->next_pg) | |
1296 | pg_num = m->next_pg->pg_num; | |
1297 | else if (m->current_pg) | |
1298 | pg_num = m->current_pg->pg_num; | |
1299 | else | |
1300 | pg_num = 1; | |
1301 | ||
1302 | DMEMIT("%u ", pg_num); | |
1303 | ||
1304 | switch (type) { | |
1305 | case STATUSTYPE_INFO: | |
1306 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1307 | if (pg->bypassed) | |
1308 | state = 'D'; /* Disabled */ | |
1309 | else if (pg == m->current_pg) | |
1310 | state = 'A'; /* Currently Active */ | |
1311 | else | |
1312 | state = 'E'; /* Enabled */ | |
1313 | ||
1314 | DMEMIT("%c ", state); | |
1315 | ||
1316 | if (pg->ps.type->status) | |
1317 | sz += pg->ps.type->status(&pg->ps, NULL, type, | |
1318 | result + sz, | |
1319 | maxlen - sz); | |
1320 | else | |
1321 | DMEMIT("0 "); | |
1322 | ||
1323 | DMEMIT("%u %u ", pg->nr_pgpaths, | |
1324 | pg->ps.type->info_args); | |
1325 | ||
1326 | list_for_each_entry(p, &pg->pgpaths, list) { | |
1327 | DMEMIT("%s %s %u ", p->path.dev->name, | |
6680073d | 1328 | p->is_active ? "A" : "F", |
1da177e4 LT |
1329 | p->fail_count); |
1330 | if (pg->ps.type->status) | |
1331 | sz += pg->ps.type->status(&pg->ps, | |
1332 | &p->path, type, result + sz, | |
1333 | maxlen - sz); | |
1334 | } | |
1335 | } | |
1336 | break; | |
1337 | ||
1338 | case STATUSTYPE_TABLE: | |
1339 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1340 | DMEMIT("%s ", pg->ps.type->name); | |
1341 | ||
1342 | if (pg->ps.type->status) | |
1343 | sz += pg->ps.type->status(&pg->ps, NULL, type, | |
1344 | result + sz, | |
1345 | maxlen - sz); | |
1346 | else | |
1347 | DMEMIT("0 "); | |
1348 | ||
1349 | DMEMIT("%u %u ", pg->nr_pgpaths, | |
1350 | pg->ps.type->table_args); | |
1351 | ||
1352 | list_for_each_entry(p, &pg->pgpaths, list) { | |
1353 | DMEMIT("%s ", p->path.dev->name); | |
1354 | if (pg->ps.type->status) | |
1355 | sz += pg->ps.type->status(&pg->ps, | |
1356 | &p->path, type, result + sz, | |
1357 | maxlen - sz); | |
1358 | } | |
1359 | } | |
1360 | break; | |
1361 | } | |
1362 | ||
1363 | spin_unlock_irqrestore(&m->lock, flags); | |
1364 | ||
1365 | return 0; | |
1366 | } | |
1367 | ||
1368 | static int multipath_message(struct dm_target *ti, unsigned argc, char **argv) | |
1369 | { | |
1370 | int r; | |
1371 | struct dm_dev *dev; | |
1372 | struct multipath *m = (struct multipath *) ti->private; | |
1373 | action_fn action; | |
1374 | ||
1375 | if (argc == 1) { | |
1376 | if (!strnicmp(argv[0], MESG_STR("queue_if_no_path"))) | |
485ef69e | 1377 | return queue_if_no_path(m, 1, 0); |
1da177e4 | 1378 | else if (!strnicmp(argv[0], MESG_STR("fail_if_no_path"))) |
485ef69e | 1379 | return queue_if_no_path(m, 0, 0); |
1da177e4 LT |
1380 | } |
1381 | ||
1382 | if (argc != 2) | |
1383 | goto error; | |
1384 | ||
1385 | if (!strnicmp(argv[0], MESG_STR("disable_group"))) | |
1386 | return bypass_pg_num(m, argv[1], 1); | |
1387 | else if (!strnicmp(argv[0], MESG_STR("enable_group"))) | |
1388 | return bypass_pg_num(m, argv[1], 0); | |
1389 | else if (!strnicmp(argv[0], MESG_STR("switch_group"))) | |
1390 | return switch_pg_num(m, argv[1]); | |
1391 | else if (!strnicmp(argv[0], MESG_STR("reinstate_path"))) | |
1392 | action = reinstate_path; | |
1393 | else if (!strnicmp(argv[0], MESG_STR("fail_path"))) | |
1394 | action = fail_path; | |
1395 | else | |
1396 | goto error; | |
1397 | ||
1398 | r = dm_get_device(ti, argv[1], ti->begin, ti->len, | |
1399 | dm_table_get_mode(ti->table), &dev); | |
1400 | if (r) { | |
72d94861 | 1401 | DMWARN("message: error getting device %s", |
1da177e4 LT |
1402 | argv[1]); |
1403 | return -EINVAL; | |
1404 | } | |
1405 | ||
1406 | r = action_dev(m, dev, action); | |
1407 | ||
1408 | dm_put_device(ti, dev); | |
1409 | ||
1410 | return r; | |
1411 | ||
1412 | error: | |
1413 | DMWARN("Unrecognised multipath message received."); | |
1414 | return -EINVAL; | |
1415 | } | |
1416 | ||
647b3d00 | 1417 | static int multipath_ioctl(struct dm_target *ti, unsigned int cmd, |
9af4aa30 MB |
1418 | unsigned long arg) |
1419 | { | |
1420 | struct multipath *m = (struct multipath *) ti->private; | |
1421 | struct block_device *bdev = NULL; | |
633a08b8 | 1422 | fmode_t mode = 0; |
9af4aa30 MB |
1423 | unsigned long flags; |
1424 | int r = 0; | |
1425 | ||
1426 | spin_lock_irqsave(&m->lock, flags); | |
1427 | ||
1428 | if (!m->current_pgpath) | |
02ab823f | 1429 | __choose_pgpath(m, 0); |
9af4aa30 | 1430 | |
e90dae1f | 1431 | if (m->current_pgpath) { |
9af4aa30 | 1432 | bdev = m->current_pgpath->path.dev->bdev; |
633a08b8 | 1433 | mode = m->current_pgpath->path.dev->mode; |
e90dae1f | 1434 | } |
9af4aa30 MB |
1435 | |
1436 | if (m->queue_io) | |
1437 | r = -EAGAIN; | |
1438 | else if (!bdev) | |
1439 | r = -EIO; | |
1440 | ||
1441 | spin_unlock_irqrestore(&m->lock, flags); | |
1442 | ||
633a08b8 | 1443 | return r ? : __blkdev_driver_ioctl(bdev, mode, cmd, arg); |
9af4aa30 MB |
1444 | } |
1445 | ||
af4874e0 MS |
1446 | static int multipath_iterate_devices(struct dm_target *ti, |
1447 | iterate_devices_callout_fn fn, void *data) | |
1448 | { | |
1449 | struct multipath *m = ti->private; | |
1450 | struct priority_group *pg; | |
1451 | struct pgpath *p; | |
1452 | int ret = 0; | |
1453 | ||
1454 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1455 | list_for_each_entry(p, &pg->pgpaths, list) { | |
5dea271b | 1456 | ret = fn(ti, p->path.dev, ti->begin, ti->len, data); |
af4874e0 MS |
1457 | if (ret) |
1458 | goto out; | |
1459 | } | |
1460 | } | |
1461 | ||
1462 | out: | |
1463 | return ret; | |
1464 | } | |
1465 | ||
f40c67f0 KU |
1466 | static int __pgpath_busy(struct pgpath *pgpath) |
1467 | { | |
1468 | struct request_queue *q = bdev_get_queue(pgpath->path.dev->bdev); | |
1469 | ||
1470 | return dm_underlying_device_busy(q); | |
1471 | } | |
1472 | ||
1473 | /* | |
1474 | * We return "busy", only when we can map I/Os but underlying devices | |
1475 | * are busy (so even if we map I/Os now, the I/Os will wait on | |
1476 | * the underlying queue). | |
1477 | * In other words, if we want to kill I/Os or queue them inside us | |
1478 | * due to map unavailability, we don't return "busy". Otherwise, | |
1479 | * dm core won't give us the I/Os and we can't do what we want. | |
1480 | */ | |
1481 | static int multipath_busy(struct dm_target *ti) | |
1482 | { | |
1483 | int busy = 0, has_active = 0; | |
1484 | struct multipath *m = ti->private; | |
1485 | struct priority_group *pg; | |
1486 | struct pgpath *pgpath; | |
1487 | unsigned long flags; | |
1488 | ||
1489 | spin_lock_irqsave(&m->lock, flags); | |
1490 | ||
1491 | /* Guess which priority_group will be used at next mapping time */ | |
1492 | if (unlikely(!m->current_pgpath && m->next_pg)) | |
1493 | pg = m->next_pg; | |
1494 | else if (likely(m->current_pg)) | |
1495 | pg = m->current_pg; | |
1496 | else | |
1497 | /* | |
1498 | * We don't know which pg will be used at next mapping time. | |
1499 | * We don't call __choose_pgpath() here to avoid to trigger | |
1500 | * pg_init just by busy checking. | |
1501 | * So we don't know whether underlying devices we will be using | |
1502 | * at next mapping time are busy or not. Just try mapping. | |
1503 | */ | |
1504 | goto out; | |
1505 | ||
1506 | /* | |
1507 | * If there is one non-busy active path at least, the path selector | |
1508 | * will be able to select it. So we consider such a pg as not busy. | |
1509 | */ | |
1510 | busy = 1; | |
1511 | list_for_each_entry(pgpath, &pg->pgpaths, list) | |
1512 | if (pgpath->is_active) { | |
1513 | has_active = 1; | |
1514 | ||
1515 | if (!__pgpath_busy(pgpath)) { | |
1516 | busy = 0; | |
1517 | break; | |
1518 | } | |
1519 | } | |
1520 | ||
1521 | if (!has_active) | |
1522 | /* | |
1523 | * No active path in this pg, so this pg won't be used and | |
1524 | * the current_pg will be changed at next mapping time. | |
1525 | * We need to try mapping to determine it. | |
1526 | */ | |
1527 | busy = 0; | |
1528 | ||
1529 | out: | |
1530 | spin_unlock_irqrestore(&m->lock, flags); | |
1531 | ||
1532 | return busy; | |
1533 | } | |
1534 | ||
1da177e4 LT |
1535 | /*----------------------------------------------------------------- |
1536 | * Module setup | |
1537 | *---------------------------------------------------------------*/ | |
1538 | static struct target_type multipath_target = { | |
1539 | .name = "multipath", | |
af4874e0 | 1540 | .version = {1, 1, 0}, |
1da177e4 LT |
1541 | .module = THIS_MODULE, |
1542 | .ctr = multipath_ctr, | |
1543 | .dtr = multipath_dtr, | |
f40c67f0 KU |
1544 | .map_rq = multipath_map, |
1545 | .rq_end_io = multipath_end_io, | |
1da177e4 LT |
1546 | .presuspend = multipath_presuspend, |
1547 | .resume = multipath_resume, | |
1548 | .status = multipath_status, | |
1549 | .message = multipath_message, | |
9af4aa30 | 1550 | .ioctl = multipath_ioctl, |
af4874e0 | 1551 | .iterate_devices = multipath_iterate_devices, |
f40c67f0 | 1552 | .busy = multipath_busy, |
1da177e4 LT |
1553 | }; |
1554 | ||
1555 | static int __init dm_multipath_init(void) | |
1556 | { | |
1557 | int r; | |
1558 | ||
1559 | /* allocate a slab for the dm_ios */ | |
028867ac | 1560 | _mpio_cache = KMEM_CACHE(dm_mpath_io, 0); |
1da177e4 LT |
1561 | if (!_mpio_cache) |
1562 | return -ENOMEM; | |
1563 | ||
1564 | r = dm_register_target(&multipath_target); | |
1565 | if (r < 0) { | |
0cd33124 | 1566 | DMERR("register failed %d", r); |
1da177e4 LT |
1567 | kmem_cache_destroy(_mpio_cache); |
1568 | return -EINVAL; | |
1569 | } | |
1570 | ||
c557308e AK |
1571 | kmultipathd = create_workqueue("kmpathd"); |
1572 | if (!kmultipathd) { | |
0cd33124 | 1573 | DMERR("failed to create workqueue kmpathd"); |
c557308e AK |
1574 | dm_unregister_target(&multipath_target); |
1575 | kmem_cache_destroy(_mpio_cache); | |
1576 | return -ENOMEM; | |
1577 | } | |
1578 | ||
bab7cfc7 CS |
1579 | /* |
1580 | * A separate workqueue is used to handle the device handlers | |
1581 | * to avoid overloading existing workqueue. Overloading the | |
1582 | * old workqueue would also create a bottleneck in the | |
1583 | * path of the storage hardware device activation. | |
1584 | */ | |
1585 | kmpath_handlerd = create_singlethread_workqueue("kmpath_handlerd"); | |
1586 | if (!kmpath_handlerd) { | |
1587 | DMERR("failed to create workqueue kmpath_handlerd"); | |
1588 | destroy_workqueue(kmultipathd); | |
1589 | dm_unregister_target(&multipath_target); | |
1590 | kmem_cache_destroy(_mpio_cache); | |
1591 | return -ENOMEM; | |
1592 | } | |
1593 | ||
72d94861 | 1594 | DMINFO("version %u.%u.%u loaded", |
1da177e4 LT |
1595 | multipath_target.version[0], multipath_target.version[1], |
1596 | multipath_target.version[2]); | |
1597 | ||
1598 | return r; | |
1599 | } | |
1600 | ||
1601 | static void __exit dm_multipath_exit(void) | |
1602 | { | |
bab7cfc7 | 1603 | destroy_workqueue(kmpath_handlerd); |
c557308e AK |
1604 | destroy_workqueue(kmultipathd); |
1605 | ||
10d3bd09 | 1606 | dm_unregister_target(&multipath_target); |
1da177e4 LT |
1607 | kmem_cache_destroy(_mpio_cache); |
1608 | } | |
1609 | ||
1da177e4 LT |
1610 | module_init(dm_multipath_init); |
1611 | module_exit(dm_multipath_exit); | |
1612 | ||
1613 | MODULE_DESCRIPTION(DM_NAME " multipath target"); | |
1614 | MODULE_AUTHOR("Sistina Software <dm-devel@redhat.com>"); | |
1615 | MODULE_LICENSE("GPL"); |