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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 | ||
8 | #include <linux/device-mapper.h> | |
9 | ||
10 | #include "dm-rq.h" | |
11 | #include "dm-bio-record.h" | |
12 | #include "dm-path-selector.h" | |
13 | #include "dm-uevent.h" | |
14 | ||
15 | #include <linux/blkdev.h> | |
16 | #include <linux/ctype.h> | |
17 | #include <linux/init.h> | |
18 | #include <linux/mempool.h> | |
19 | #include <linux/module.h> | |
20 | #include <linux/pagemap.h> | |
21 | #include <linux/slab.h> | |
22 | #include <linux/time.h> | |
23 | #include <linux/workqueue.h> | |
24 | #include <linux/delay.h> | |
25 | #include <scsi/scsi_dh.h> | |
26 | #include <linux/atomic.h> | |
27 | #include <linux/blk-mq.h> | |
28 | ||
29 | #define DM_MSG_PREFIX "multipath" | |
30 | #define DM_PG_INIT_DELAY_MSECS 2000 | |
31 | #define DM_PG_INIT_DELAY_DEFAULT ((unsigned) -1) | |
32 | ||
33 | /* Path properties */ | |
34 | struct pgpath { | |
35 | struct list_head list; | |
36 | ||
37 | struct priority_group *pg; /* Owning PG */ | |
38 | unsigned fail_count; /* Cumulative failure count */ | |
39 | ||
40 | struct dm_path path; | |
41 | struct delayed_work activate_path; | |
42 | ||
43 | bool is_active:1; /* Path status */ | |
44 | }; | |
45 | ||
46 | #define path_to_pgpath(__pgp) container_of((__pgp), struct pgpath, path) | |
47 | ||
48 | /* | |
49 | * Paths are grouped into Priority Groups and numbered from 1 upwards. | |
50 | * Each has a path selector which controls which path gets used. | |
51 | */ | |
52 | struct priority_group { | |
53 | struct list_head list; | |
54 | ||
55 | struct multipath *m; /* Owning multipath instance */ | |
56 | struct path_selector ps; | |
57 | ||
58 | unsigned pg_num; /* Reference number */ | |
59 | unsigned nr_pgpaths; /* Number of paths in PG */ | |
60 | struct list_head pgpaths; | |
61 | ||
62 | bool bypassed:1; /* Temporarily bypass this PG? */ | |
63 | }; | |
64 | ||
65 | /* Multipath context */ | |
66 | struct multipath { | |
67 | struct list_head list; | |
68 | struct dm_target *ti; | |
69 | ||
70 | const char *hw_handler_name; | |
71 | char *hw_handler_params; | |
72 | ||
73 | spinlock_t lock; | |
74 | ||
75 | unsigned nr_priority_groups; | |
76 | struct list_head priority_groups; | |
77 | ||
78 | wait_queue_head_t pg_init_wait; /* Wait for pg_init completion */ | |
79 | ||
80 | struct pgpath *current_pgpath; | |
81 | struct priority_group *current_pg; | |
82 | struct priority_group *next_pg; /* Switch to this PG if set */ | |
83 | ||
84 | unsigned long flags; /* Multipath state flags */ | |
85 | ||
86 | unsigned pg_init_retries; /* Number of times to retry pg_init */ | |
87 | unsigned pg_init_delay_msecs; /* Number of msecs before pg_init retry */ | |
88 | ||
89 | atomic_t nr_valid_paths; /* Total number of usable paths */ | |
90 | atomic_t pg_init_in_progress; /* Only one pg_init allowed at once */ | |
91 | atomic_t pg_init_count; /* Number of times pg_init called */ | |
92 | ||
93 | enum dm_queue_mode queue_mode; | |
94 | ||
95 | struct mutex work_mutex; | |
96 | struct work_struct trigger_event; | |
97 | ||
98 | struct work_struct process_queued_bios; | |
99 | struct bio_list queued_bios; | |
100 | }; | |
101 | ||
102 | /* | |
103 | * Context information attached to each io we process. | |
104 | */ | |
105 | struct dm_mpath_io { | |
106 | struct pgpath *pgpath; | |
107 | size_t nr_bytes; | |
108 | }; | |
109 | ||
110 | typedef int (*action_fn) (struct pgpath *pgpath); | |
111 | ||
112 | static struct workqueue_struct *kmultipathd, *kmpath_handlerd; | |
113 | static void trigger_event(struct work_struct *work); | |
114 | static void activate_or_offline_path(struct pgpath *pgpath); | |
115 | static void activate_path_work(struct work_struct *work); | |
116 | static void process_queued_bios(struct work_struct *work); | |
117 | ||
118 | /*----------------------------------------------- | |
119 | * Multipath state flags. | |
120 | *-----------------------------------------------*/ | |
121 | ||
122 | #define MPATHF_QUEUE_IO 0 /* Must we queue all I/O? */ | |
123 | #define MPATHF_QUEUE_IF_NO_PATH 1 /* Queue I/O if last path fails? */ | |
124 | #define MPATHF_SAVED_QUEUE_IF_NO_PATH 2 /* Saved state during suspension */ | |
125 | #define MPATHF_RETAIN_ATTACHED_HW_HANDLER 3 /* If there's already a hw_handler present, don't change it. */ | |
126 | #define MPATHF_PG_INIT_DISABLED 4 /* pg_init is not currently allowed */ | |
127 | #define MPATHF_PG_INIT_REQUIRED 5 /* pg_init needs calling? */ | |
128 | #define MPATHF_PG_INIT_DELAY_RETRY 6 /* Delay pg_init retry? */ | |
129 | ||
130 | /*----------------------------------------------- | |
131 | * Allocation routines | |
132 | *-----------------------------------------------*/ | |
133 | ||
134 | static struct pgpath *alloc_pgpath(void) | |
135 | { | |
136 | struct pgpath *pgpath = kzalloc(sizeof(*pgpath), GFP_KERNEL); | |
137 | ||
138 | if (pgpath) { | |
139 | pgpath->is_active = true; | |
140 | INIT_DELAYED_WORK(&pgpath->activate_path, activate_path_work); | |
141 | } | |
142 | ||
143 | return pgpath; | |
144 | } | |
145 | ||
146 | static void free_pgpath(struct pgpath *pgpath) | |
147 | { | |
148 | kfree(pgpath); | |
149 | } | |
150 | ||
151 | static struct priority_group *alloc_priority_group(void) | |
152 | { | |
153 | struct priority_group *pg; | |
154 | ||
155 | pg = kzalloc(sizeof(*pg), GFP_KERNEL); | |
156 | ||
157 | if (pg) | |
158 | INIT_LIST_HEAD(&pg->pgpaths); | |
159 | ||
160 | return pg; | |
161 | } | |
162 | ||
163 | static void free_pgpaths(struct list_head *pgpaths, struct dm_target *ti) | |
164 | { | |
165 | struct pgpath *pgpath, *tmp; | |
166 | ||
167 | list_for_each_entry_safe(pgpath, tmp, pgpaths, list) { | |
168 | list_del(&pgpath->list); | |
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 | ||
188 | static struct multipath *alloc_multipath(struct dm_target *ti) | |
189 | { | |
190 | struct multipath *m; | |
191 | ||
192 | m = kzalloc(sizeof(*m), GFP_KERNEL); | |
193 | if (m) { | |
194 | INIT_LIST_HEAD(&m->priority_groups); | |
195 | spin_lock_init(&m->lock); | |
196 | set_bit(MPATHF_QUEUE_IO, &m->flags); | |
197 | atomic_set(&m->nr_valid_paths, 0); | |
198 | atomic_set(&m->pg_init_in_progress, 0); | |
199 | atomic_set(&m->pg_init_count, 0); | |
200 | m->pg_init_delay_msecs = DM_PG_INIT_DELAY_DEFAULT; | |
201 | INIT_WORK(&m->trigger_event, trigger_event); | |
202 | init_waitqueue_head(&m->pg_init_wait); | |
203 | mutex_init(&m->work_mutex); | |
204 | ||
205 | m->queue_mode = DM_TYPE_NONE; | |
206 | ||
207 | m->ti = ti; | |
208 | ti->private = m; | |
209 | } | |
210 | ||
211 | return m; | |
212 | } | |
213 | ||
214 | static int alloc_multipath_stage2(struct dm_target *ti, struct multipath *m) | |
215 | { | |
216 | if (m->queue_mode == DM_TYPE_NONE) { | |
217 | /* | |
218 | * Default to request-based. | |
219 | */ | |
220 | if (dm_use_blk_mq(dm_table_get_md(ti->table))) | |
221 | m->queue_mode = DM_TYPE_MQ_REQUEST_BASED; | |
222 | else | |
223 | m->queue_mode = DM_TYPE_REQUEST_BASED; | |
224 | } else if (m->queue_mode == DM_TYPE_BIO_BASED) { | |
225 | INIT_WORK(&m->process_queued_bios, process_queued_bios); | |
226 | /* | |
227 | * bio-based doesn't support any direct scsi_dh management; | |
228 | * it just discovers if a scsi_dh is attached. | |
229 | */ | |
230 | set_bit(MPATHF_RETAIN_ATTACHED_HW_HANDLER, &m->flags); | |
231 | } | |
232 | ||
233 | dm_table_set_type(ti->table, m->queue_mode); | |
234 | ||
235 | return 0; | |
236 | } | |
237 | ||
238 | static void free_multipath(struct multipath *m) | |
239 | { | |
240 | struct priority_group *pg, *tmp; | |
241 | ||
242 | list_for_each_entry_safe(pg, tmp, &m->priority_groups, list) { | |
243 | list_del(&pg->list); | |
244 | free_priority_group(pg, m->ti); | |
245 | } | |
246 | ||
247 | kfree(m->hw_handler_name); | |
248 | kfree(m->hw_handler_params); | |
249 | kfree(m); | |
250 | } | |
251 | ||
252 | static struct dm_mpath_io *get_mpio(union map_info *info) | |
253 | { | |
254 | return info->ptr; | |
255 | } | |
256 | ||
257 | static size_t multipath_per_bio_data_size(void) | |
258 | { | |
259 | return sizeof(struct dm_mpath_io) + sizeof(struct dm_bio_details); | |
260 | } | |
261 | ||
262 | static struct dm_mpath_io *get_mpio_from_bio(struct bio *bio) | |
263 | { | |
264 | return dm_per_bio_data(bio, multipath_per_bio_data_size()); | |
265 | } | |
266 | ||
267 | static struct dm_bio_details *get_bio_details_from_bio(struct bio *bio) | |
268 | { | |
269 | /* dm_bio_details is immediately after the dm_mpath_io in bio's per-bio-data */ | |
270 | struct dm_mpath_io *mpio = get_mpio_from_bio(bio); | |
271 | void *bio_details = mpio + 1; | |
272 | ||
273 | return bio_details; | |
274 | } | |
275 | ||
276 | static void multipath_init_per_bio_data(struct bio *bio, struct dm_mpath_io **mpio_p, | |
277 | struct dm_bio_details **bio_details_p) | |
278 | { | |
279 | struct dm_mpath_io *mpio = get_mpio_from_bio(bio); | |
280 | struct dm_bio_details *bio_details = get_bio_details_from_bio(bio); | |
281 | ||
282 | memset(mpio, 0, sizeof(*mpio)); | |
283 | memset(bio_details, 0, sizeof(*bio_details)); | |
284 | dm_bio_record(bio_details, bio); | |
285 | ||
286 | if (mpio_p) | |
287 | *mpio_p = mpio; | |
288 | if (bio_details_p) | |
289 | *bio_details_p = bio_details; | |
290 | } | |
291 | ||
292 | /*----------------------------------------------- | |
293 | * Path selection | |
294 | *-----------------------------------------------*/ | |
295 | ||
296 | static int __pg_init_all_paths(struct multipath *m) | |
297 | { | |
298 | struct pgpath *pgpath; | |
299 | unsigned long pg_init_delay = 0; | |
300 | ||
301 | lockdep_assert_held(&m->lock); | |
302 | ||
303 | if (atomic_read(&m->pg_init_in_progress) || test_bit(MPATHF_PG_INIT_DISABLED, &m->flags)) | |
304 | return 0; | |
305 | ||
306 | atomic_inc(&m->pg_init_count); | |
307 | clear_bit(MPATHF_PG_INIT_REQUIRED, &m->flags); | |
308 | ||
309 | /* Check here to reset pg_init_required */ | |
310 | if (!m->current_pg) | |
311 | return 0; | |
312 | ||
313 | if (test_bit(MPATHF_PG_INIT_DELAY_RETRY, &m->flags)) | |
314 | pg_init_delay = msecs_to_jiffies(m->pg_init_delay_msecs != DM_PG_INIT_DELAY_DEFAULT ? | |
315 | m->pg_init_delay_msecs : DM_PG_INIT_DELAY_MSECS); | |
316 | list_for_each_entry(pgpath, &m->current_pg->pgpaths, list) { | |
317 | /* Skip failed paths */ | |
318 | if (!pgpath->is_active) | |
319 | continue; | |
320 | if (queue_delayed_work(kmpath_handlerd, &pgpath->activate_path, | |
321 | pg_init_delay)) | |
322 | atomic_inc(&m->pg_init_in_progress); | |
323 | } | |
324 | return atomic_read(&m->pg_init_in_progress); | |
325 | } | |
326 | ||
327 | static int pg_init_all_paths(struct multipath *m) | |
328 | { | |
329 | int ret; | |
330 | unsigned long flags; | |
331 | ||
332 | spin_lock_irqsave(&m->lock, flags); | |
333 | ret = __pg_init_all_paths(m); | |
334 | spin_unlock_irqrestore(&m->lock, flags); | |
335 | ||
336 | return ret; | |
337 | } | |
338 | ||
339 | static void __switch_pg(struct multipath *m, struct priority_group *pg) | |
340 | { | |
341 | m->current_pg = pg; | |
342 | ||
343 | /* Must we initialise the PG first, and queue I/O till it's ready? */ | |
344 | if (m->hw_handler_name) { | |
345 | set_bit(MPATHF_PG_INIT_REQUIRED, &m->flags); | |
346 | set_bit(MPATHF_QUEUE_IO, &m->flags); | |
347 | } else { | |
348 | clear_bit(MPATHF_PG_INIT_REQUIRED, &m->flags); | |
349 | clear_bit(MPATHF_QUEUE_IO, &m->flags); | |
350 | } | |
351 | ||
352 | atomic_set(&m->pg_init_count, 0); | |
353 | } | |
354 | ||
355 | static struct pgpath *choose_path_in_pg(struct multipath *m, | |
356 | struct priority_group *pg, | |
357 | size_t nr_bytes) | |
358 | { | |
359 | unsigned long flags; | |
360 | struct dm_path *path; | |
361 | struct pgpath *pgpath; | |
362 | ||
363 | path = pg->ps.type->select_path(&pg->ps, nr_bytes); | |
364 | if (!path) | |
365 | return ERR_PTR(-ENXIO); | |
366 | ||
367 | pgpath = path_to_pgpath(path); | |
368 | ||
369 | if (unlikely(READ_ONCE(m->current_pg) != pg)) { | |
370 | /* Only update current_pgpath if pg changed */ | |
371 | spin_lock_irqsave(&m->lock, flags); | |
372 | m->current_pgpath = pgpath; | |
373 | __switch_pg(m, pg); | |
374 | spin_unlock_irqrestore(&m->lock, flags); | |
375 | } | |
376 | ||
377 | return pgpath; | |
378 | } | |
379 | ||
380 | static struct pgpath *choose_pgpath(struct multipath *m, size_t nr_bytes) | |
381 | { | |
382 | unsigned long flags; | |
383 | struct priority_group *pg; | |
384 | struct pgpath *pgpath; | |
385 | unsigned bypassed = 1; | |
386 | ||
387 | if (!atomic_read(&m->nr_valid_paths)) { | |
388 | clear_bit(MPATHF_QUEUE_IO, &m->flags); | |
389 | goto failed; | |
390 | } | |
391 | ||
392 | /* Were we instructed to switch PG? */ | |
393 | if (READ_ONCE(m->next_pg)) { | |
394 | spin_lock_irqsave(&m->lock, flags); | |
395 | pg = m->next_pg; | |
396 | if (!pg) { | |
397 | spin_unlock_irqrestore(&m->lock, flags); | |
398 | goto check_current_pg; | |
399 | } | |
400 | m->next_pg = NULL; | |
401 | spin_unlock_irqrestore(&m->lock, flags); | |
402 | pgpath = choose_path_in_pg(m, pg, nr_bytes); | |
403 | if (!IS_ERR_OR_NULL(pgpath)) | |
404 | return pgpath; | |
405 | } | |
406 | ||
407 | /* Don't change PG until it has no remaining paths */ | |
408 | check_current_pg: | |
409 | pg = READ_ONCE(m->current_pg); | |
410 | if (pg) { | |
411 | pgpath = choose_path_in_pg(m, pg, nr_bytes); | |
412 | if (!IS_ERR_OR_NULL(pgpath)) | |
413 | return pgpath; | |
414 | } | |
415 | ||
416 | /* | |
417 | * Loop through priority groups until we find a valid path. | |
418 | * First time we skip PGs marked 'bypassed'. | |
419 | * Second time we only try the ones we skipped, but set | |
420 | * pg_init_delay_retry so we do not hammer controllers. | |
421 | */ | |
422 | do { | |
423 | list_for_each_entry(pg, &m->priority_groups, list) { | |
424 | if (pg->bypassed == !!bypassed) | |
425 | continue; | |
426 | pgpath = choose_path_in_pg(m, pg, nr_bytes); | |
427 | if (!IS_ERR_OR_NULL(pgpath)) { | |
428 | if (!bypassed) | |
429 | set_bit(MPATHF_PG_INIT_DELAY_RETRY, &m->flags); | |
430 | return pgpath; | |
431 | } | |
432 | } | |
433 | } while (bypassed--); | |
434 | ||
435 | failed: | |
436 | spin_lock_irqsave(&m->lock, flags); | |
437 | m->current_pgpath = NULL; | |
438 | m->current_pg = NULL; | |
439 | spin_unlock_irqrestore(&m->lock, flags); | |
440 | ||
441 | return NULL; | |
442 | } | |
443 | ||
444 | /* | |
445 | * dm_report_EIO() is a macro instead of a function to make pr_debug() | |
446 | * report the function name and line number of the function from which | |
447 | * it has been invoked. | |
448 | */ | |
449 | #define dm_report_EIO(m) \ | |
450 | do { \ | |
451 | struct mapped_device *md = dm_table_get_md((m)->ti->table); \ | |
452 | \ | |
453 | pr_debug("%s: returning EIO; QIFNP = %d; SQIFNP = %d; DNFS = %d\n", \ | |
454 | dm_device_name(md), \ | |
455 | test_bit(MPATHF_QUEUE_IF_NO_PATH, &(m)->flags), \ | |
456 | test_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &(m)->flags), \ | |
457 | dm_noflush_suspending((m)->ti)); \ | |
458 | } while (0) | |
459 | ||
460 | /* | |
461 | * Map cloned requests (request-based multipath) | |
462 | */ | |
463 | static int multipath_clone_and_map(struct dm_target *ti, struct request *rq, | |
464 | union map_info *map_context, | |
465 | struct request **__clone) | |
466 | { | |
467 | struct multipath *m = ti->private; | |
468 | size_t nr_bytes = blk_rq_bytes(rq); | |
469 | struct pgpath *pgpath; | |
470 | struct block_device *bdev; | |
471 | struct dm_mpath_io *mpio = get_mpio(map_context); | |
472 | struct request_queue *q; | |
473 | struct request *clone; | |
474 | ||
475 | /* Do we need to select a new pgpath? */ | |
476 | pgpath = READ_ONCE(m->current_pgpath); | |
477 | if (!pgpath || !test_bit(MPATHF_QUEUE_IO, &m->flags)) | |
478 | pgpath = choose_pgpath(m, nr_bytes); | |
479 | ||
480 | if (!pgpath) { | |
481 | if (test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) | |
482 | return DM_MAPIO_DELAY_REQUEUE; | |
483 | dm_report_EIO(m); /* Failed */ | |
484 | return DM_MAPIO_KILL; | |
485 | } else if (test_bit(MPATHF_QUEUE_IO, &m->flags) || | |
486 | test_bit(MPATHF_PG_INIT_REQUIRED, &m->flags)) { | |
487 | if (pg_init_all_paths(m)) | |
488 | return DM_MAPIO_DELAY_REQUEUE; | |
489 | return DM_MAPIO_REQUEUE; | |
490 | } | |
491 | ||
492 | memset(mpio, 0, sizeof(*mpio)); | |
493 | mpio->pgpath = pgpath; | |
494 | mpio->nr_bytes = nr_bytes; | |
495 | ||
496 | bdev = pgpath->path.dev->bdev; | |
497 | q = bdev_get_queue(bdev); | |
498 | clone = blk_get_request(q, rq->cmd_flags | REQ_NOMERGE, GFP_ATOMIC); | |
499 | if (IS_ERR(clone)) { | |
500 | /* EBUSY, ENODEV or EWOULDBLOCK: requeue */ | |
501 | bool queue_dying = blk_queue_dying(q); | |
502 | DMERR_LIMIT("blk_get_request() returned %ld%s - requeuing", | |
503 | PTR_ERR(clone), queue_dying ? " (path offline)" : ""); | |
504 | if (queue_dying) { | |
505 | atomic_inc(&m->pg_init_in_progress); | |
506 | activate_or_offline_path(pgpath); | |
507 | } | |
508 | return DM_MAPIO_DELAY_REQUEUE; | |
509 | } | |
510 | clone->bio = clone->biotail = NULL; | |
511 | clone->rq_disk = bdev->bd_disk; | |
512 | clone->cmd_flags |= REQ_FAILFAST_TRANSPORT; | |
513 | *__clone = clone; | |
514 | ||
515 | if (pgpath->pg->ps.type->start_io) | |
516 | pgpath->pg->ps.type->start_io(&pgpath->pg->ps, | |
517 | &pgpath->path, | |
518 | nr_bytes); | |
519 | return DM_MAPIO_REMAPPED; | |
520 | } | |
521 | ||
522 | static void multipath_release_clone(struct request *clone) | |
523 | { | |
524 | blk_put_request(clone); | |
525 | } | |
526 | ||
527 | /* | |
528 | * Map cloned bios (bio-based multipath) | |
529 | */ | |
530 | static int __multipath_map_bio(struct multipath *m, struct bio *bio, struct dm_mpath_io *mpio) | |
531 | { | |
532 | size_t nr_bytes = bio->bi_iter.bi_size; | |
533 | struct pgpath *pgpath; | |
534 | unsigned long flags; | |
535 | bool queue_io; | |
536 | ||
537 | /* Do we need to select a new pgpath? */ | |
538 | pgpath = READ_ONCE(m->current_pgpath); | |
539 | queue_io = test_bit(MPATHF_QUEUE_IO, &m->flags); | |
540 | if (!pgpath || !queue_io) | |
541 | pgpath = choose_pgpath(m, nr_bytes); | |
542 | ||
543 | if ((pgpath && queue_io) || | |
544 | (!pgpath && test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags))) { | |
545 | /* Queue for the daemon to resubmit */ | |
546 | spin_lock_irqsave(&m->lock, flags); | |
547 | bio_list_add(&m->queued_bios, bio); | |
548 | spin_unlock_irqrestore(&m->lock, flags); | |
549 | /* PG_INIT_REQUIRED cannot be set without QUEUE_IO */ | |
550 | if (queue_io || test_bit(MPATHF_PG_INIT_REQUIRED, &m->flags)) | |
551 | pg_init_all_paths(m); | |
552 | else if (!queue_io) | |
553 | queue_work(kmultipathd, &m->process_queued_bios); | |
554 | return DM_MAPIO_SUBMITTED; | |
555 | } | |
556 | ||
557 | if (!pgpath) { | |
558 | if (test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) | |
559 | return DM_MAPIO_REQUEUE; | |
560 | dm_report_EIO(m); | |
561 | return DM_MAPIO_KILL; | |
562 | } | |
563 | ||
564 | mpio->pgpath = pgpath; | |
565 | mpio->nr_bytes = nr_bytes; | |
566 | ||
567 | bio->bi_status = 0; | |
568 | bio->bi_bdev = pgpath->path.dev->bdev; | |
569 | bio->bi_opf |= REQ_FAILFAST_TRANSPORT; | |
570 | ||
571 | if (pgpath->pg->ps.type->start_io) | |
572 | pgpath->pg->ps.type->start_io(&pgpath->pg->ps, | |
573 | &pgpath->path, | |
574 | nr_bytes); | |
575 | return DM_MAPIO_REMAPPED; | |
576 | } | |
577 | ||
578 | static int multipath_map_bio(struct dm_target *ti, struct bio *bio) | |
579 | { | |
580 | struct multipath *m = ti->private; | |
581 | struct dm_mpath_io *mpio = NULL; | |
582 | ||
583 | multipath_init_per_bio_data(bio, &mpio, NULL); | |
584 | ||
585 | return __multipath_map_bio(m, bio, mpio); | |
586 | } | |
587 | ||
588 | static void process_queued_io_list(struct multipath *m) | |
589 | { | |
590 | if (m->queue_mode == DM_TYPE_MQ_REQUEST_BASED) | |
591 | dm_mq_kick_requeue_list(dm_table_get_md(m->ti->table)); | |
592 | else if (m->queue_mode == DM_TYPE_BIO_BASED) | |
593 | queue_work(kmultipathd, &m->process_queued_bios); | |
594 | } | |
595 | ||
596 | static void process_queued_bios(struct work_struct *work) | |
597 | { | |
598 | int r; | |
599 | unsigned long flags; | |
600 | struct bio *bio; | |
601 | struct bio_list bios; | |
602 | struct blk_plug plug; | |
603 | struct multipath *m = | |
604 | container_of(work, struct multipath, process_queued_bios); | |
605 | ||
606 | bio_list_init(&bios); | |
607 | ||
608 | spin_lock_irqsave(&m->lock, flags); | |
609 | ||
610 | if (bio_list_empty(&m->queued_bios)) { | |
611 | spin_unlock_irqrestore(&m->lock, flags); | |
612 | return; | |
613 | } | |
614 | ||
615 | bio_list_merge(&bios, &m->queued_bios); | |
616 | bio_list_init(&m->queued_bios); | |
617 | ||
618 | spin_unlock_irqrestore(&m->lock, flags); | |
619 | ||
620 | blk_start_plug(&plug); | |
621 | while ((bio = bio_list_pop(&bios))) { | |
622 | r = __multipath_map_bio(m, bio, get_mpio_from_bio(bio)); | |
623 | switch (r) { | |
624 | case DM_MAPIO_KILL: | |
625 | bio->bi_status = BLK_STS_IOERR; | |
626 | bio_endio(bio); | |
627 | break; | |
628 | case DM_MAPIO_REQUEUE: | |
629 | bio->bi_status = BLK_STS_DM_REQUEUE; | |
630 | bio_endio(bio); | |
631 | break; | |
632 | case DM_MAPIO_REMAPPED: | |
633 | generic_make_request(bio); | |
634 | break; | |
635 | } | |
636 | } | |
637 | blk_finish_plug(&plug); | |
638 | } | |
639 | ||
640 | static void assign_bit(bool value, long nr, unsigned long *addr) | |
641 | { | |
642 | if (value) | |
643 | set_bit(nr, addr); | |
644 | else | |
645 | clear_bit(nr, addr); | |
646 | } | |
647 | ||
648 | /* | |
649 | * If we run out of usable paths, should we queue I/O or error it? | |
650 | */ | |
651 | static int queue_if_no_path(struct multipath *m, bool queue_if_no_path, | |
652 | bool save_old_value) | |
653 | { | |
654 | unsigned long flags; | |
655 | ||
656 | spin_lock_irqsave(&m->lock, flags); | |
657 | assign_bit((save_old_value && test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) || | |
658 | (!save_old_value && queue_if_no_path), | |
659 | MPATHF_SAVED_QUEUE_IF_NO_PATH, &m->flags); | |
660 | assign_bit(queue_if_no_path || dm_noflush_suspending(m->ti), | |
661 | MPATHF_QUEUE_IF_NO_PATH, &m->flags); | |
662 | spin_unlock_irqrestore(&m->lock, flags); | |
663 | ||
664 | if (!queue_if_no_path) { | |
665 | dm_table_run_md_queue_async(m->ti->table); | |
666 | process_queued_io_list(m); | |
667 | } | |
668 | ||
669 | return 0; | |
670 | } | |
671 | ||
672 | /* | |
673 | * An event is triggered whenever a path is taken out of use. | |
674 | * Includes path failure and PG bypass. | |
675 | */ | |
676 | static void trigger_event(struct work_struct *work) | |
677 | { | |
678 | struct multipath *m = | |
679 | container_of(work, struct multipath, trigger_event); | |
680 | ||
681 | dm_table_event(m->ti->table); | |
682 | } | |
683 | ||
684 | /*----------------------------------------------------------------- | |
685 | * Constructor/argument parsing: | |
686 | * <#multipath feature args> [<arg>]* | |
687 | * <#hw_handler args> [hw_handler [<arg>]*] | |
688 | * <#priority groups> | |
689 | * <initial priority group> | |
690 | * [<selector> <#selector args> [<arg>]* | |
691 | * <#paths> <#per-path selector args> | |
692 | * [<path> [<arg>]* ]+ ]+ | |
693 | *---------------------------------------------------------------*/ | |
694 | static int parse_path_selector(struct dm_arg_set *as, struct priority_group *pg, | |
695 | struct dm_target *ti) | |
696 | { | |
697 | int r; | |
698 | struct path_selector_type *pst; | |
699 | unsigned ps_argc; | |
700 | ||
701 | static struct dm_arg _args[] = { | |
702 | {0, 1024, "invalid number of path selector args"}, | |
703 | }; | |
704 | ||
705 | pst = dm_get_path_selector(dm_shift_arg(as)); | |
706 | if (!pst) { | |
707 | ti->error = "unknown path selector type"; | |
708 | return -EINVAL; | |
709 | } | |
710 | ||
711 | r = dm_read_arg_group(_args, as, &ps_argc, &ti->error); | |
712 | if (r) { | |
713 | dm_put_path_selector(pst); | |
714 | return -EINVAL; | |
715 | } | |
716 | ||
717 | r = pst->create(&pg->ps, ps_argc, as->argv); | |
718 | if (r) { | |
719 | dm_put_path_selector(pst); | |
720 | ti->error = "path selector constructor failed"; | |
721 | return r; | |
722 | } | |
723 | ||
724 | pg->ps.type = pst; | |
725 | dm_consume_args(as, ps_argc); | |
726 | ||
727 | return 0; | |
728 | } | |
729 | ||
730 | static struct pgpath *parse_path(struct dm_arg_set *as, struct path_selector *ps, | |
731 | struct dm_target *ti) | |
732 | { | |
733 | int r; | |
734 | struct pgpath *p; | |
735 | struct multipath *m = ti->private; | |
736 | struct request_queue *q = NULL; | |
737 | const char *attached_handler_name; | |
738 | ||
739 | /* we need at least a path arg */ | |
740 | if (as->argc < 1) { | |
741 | ti->error = "no device given"; | |
742 | return ERR_PTR(-EINVAL); | |
743 | } | |
744 | ||
745 | p = alloc_pgpath(); | |
746 | if (!p) | |
747 | return ERR_PTR(-ENOMEM); | |
748 | ||
749 | r = dm_get_device(ti, dm_shift_arg(as), dm_table_get_mode(ti->table), | |
750 | &p->path.dev); | |
751 | if (r) { | |
752 | ti->error = "error getting device"; | |
753 | goto bad; | |
754 | } | |
755 | ||
756 | if (test_bit(MPATHF_RETAIN_ATTACHED_HW_HANDLER, &m->flags) || m->hw_handler_name) | |
757 | q = bdev_get_queue(p->path.dev->bdev); | |
758 | ||
759 | if (test_bit(MPATHF_RETAIN_ATTACHED_HW_HANDLER, &m->flags)) { | |
760 | retain: | |
761 | attached_handler_name = scsi_dh_attached_handler_name(q, GFP_KERNEL); | |
762 | if (attached_handler_name) { | |
763 | /* | |
764 | * Clear any hw_handler_params associated with a | |
765 | * handler that isn't already attached. | |
766 | */ | |
767 | if (m->hw_handler_name && strcmp(attached_handler_name, m->hw_handler_name)) { | |
768 | kfree(m->hw_handler_params); | |
769 | m->hw_handler_params = NULL; | |
770 | } | |
771 | ||
772 | /* | |
773 | * Reset hw_handler_name to match the attached handler | |
774 | * | |
775 | * NB. This modifies the table line to show the actual | |
776 | * handler instead of the original table passed in. | |
777 | */ | |
778 | kfree(m->hw_handler_name); | |
779 | m->hw_handler_name = attached_handler_name; | |
780 | } | |
781 | } | |
782 | ||
783 | if (m->hw_handler_name) { | |
784 | r = scsi_dh_attach(q, m->hw_handler_name); | |
785 | if (r == -EBUSY) { | |
786 | char b[BDEVNAME_SIZE]; | |
787 | ||
788 | printk(KERN_INFO "dm-mpath: retaining handler on device %s\n", | |
789 | bdevname(p->path.dev->bdev, b)); | |
790 | goto retain; | |
791 | } | |
792 | if (r < 0) { | |
793 | ti->error = "error attaching hardware handler"; | |
794 | dm_put_device(ti, p->path.dev); | |
795 | goto bad; | |
796 | } | |
797 | ||
798 | if (m->hw_handler_params) { | |
799 | r = scsi_dh_set_params(q, m->hw_handler_params); | |
800 | if (r < 0) { | |
801 | ti->error = "unable to set hardware " | |
802 | "handler parameters"; | |
803 | dm_put_device(ti, p->path.dev); | |
804 | goto bad; | |
805 | } | |
806 | } | |
807 | } | |
808 | ||
809 | r = ps->type->add_path(ps, &p->path, as->argc, as->argv, &ti->error); | |
810 | if (r) { | |
811 | dm_put_device(ti, p->path.dev); | |
812 | goto bad; | |
813 | } | |
814 | ||
815 | return p; | |
816 | ||
817 | bad: | |
818 | free_pgpath(p); | |
819 | return ERR_PTR(r); | |
820 | } | |
821 | ||
822 | static struct priority_group *parse_priority_group(struct dm_arg_set *as, | |
823 | struct multipath *m) | |
824 | { | |
825 | static struct dm_arg _args[] = { | |
826 | {1, 1024, "invalid number of paths"}, | |
827 | {0, 1024, "invalid number of selector args"} | |
828 | }; | |
829 | ||
830 | int r; | |
831 | unsigned i, nr_selector_args, nr_args; | |
832 | struct priority_group *pg; | |
833 | struct dm_target *ti = m->ti; | |
834 | ||
835 | if (as->argc < 2) { | |
836 | as->argc = 0; | |
837 | ti->error = "not enough priority group arguments"; | |
838 | return ERR_PTR(-EINVAL); | |
839 | } | |
840 | ||
841 | pg = alloc_priority_group(); | |
842 | if (!pg) { | |
843 | ti->error = "couldn't allocate priority group"; | |
844 | return ERR_PTR(-ENOMEM); | |
845 | } | |
846 | pg->m = m; | |
847 | ||
848 | r = parse_path_selector(as, pg, ti); | |
849 | if (r) | |
850 | goto bad; | |
851 | ||
852 | /* | |
853 | * read the paths | |
854 | */ | |
855 | r = dm_read_arg(_args, as, &pg->nr_pgpaths, &ti->error); | |
856 | if (r) | |
857 | goto bad; | |
858 | ||
859 | r = dm_read_arg(_args + 1, as, &nr_selector_args, &ti->error); | |
860 | if (r) | |
861 | goto bad; | |
862 | ||
863 | nr_args = 1 + nr_selector_args; | |
864 | for (i = 0; i < pg->nr_pgpaths; i++) { | |
865 | struct pgpath *pgpath; | |
866 | struct dm_arg_set path_args; | |
867 | ||
868 | if (as->argc < nr_args) { | |
869 | ti->error = "not enough path parameters"; | |
870 | r = -EINVAL; | |
871 | goto bad; | |
872 | } | |
873 | ||
874 | path_args.argc = nr_args; | |
875 | path_args.argv = as->argv; | |
876 | ||
877 | pgpath = parse_path(&path_args, &pg->ps, ti); | |
878 | if (IS_ERR(pgpath)) { | |
879 | r = PTR_ERR(pgpath); | |
880 | goto bad; | |
881 | } | |
882 | ||
883 | pgpath->pg = pg; | |
884 | list_add_tail(&pgpath->list, &pg->pgpaths); | |
885 | dm_consume_args(as, nr_args); | |
886 | } | |
887 | ||
888 | return pg; | |
889 | ||
890 | bad: | |
891 | free_priority_group(pg, ti); | |
892 | return ERR_PTR(r); | |
893 | } | |
894 | ||
895 | static int parse_hw_handler(struct dm_arg_set *as, struct multipath *m) | |
896 | { | |
897 | unsigned hw_argc; | |
898 | int ret; | |
899 | struct dm_target *ti = m->ti; | |
900 | ||
901 | static struct dm_arg _args[] = { | |
902 | {0, 1024, "invalid number of hardware handler args"}, | |
903 | }; | |
904 | ||
905 | if (dm_read_arg_group(_args, as, &hw_argc, &ti->error)) | |
906 | return -EINVAL; | |
907 | ||
908 | if (!hw_argc) | |
909 | return 0; | |
910 | ||
911 | if (m->queue_mode == DM_TYPE_BIO_BASED) { | |
912 | dm_consume_args(as, hw_argc); | |
913 | DMERR("bio-based multipath doesn't allow hardware handler args"); | |
914 | return 0; | |
915 | } | |
916 | ||
917 | m->hw_handler_name = kstrdup(dm_shift_arg(as), GFP_KERNEL); | |
918 | if (!m->hw_handler_name) | |
919 | return -EINVAL; | |
920 | ||
921 | if (hw_argc > 1) { | |
922 | char *p; | |
923 | int i, j, len = 4; | |
924 | ||
925 | for (i = 0; i <= hw_argc - 2; i++) | |
926 | len += strlen(as->argv[i]) + 1; | |
927 | p = m->hw_handler_params = kzalloc(len, GFP_KERNEL); | |
928 | if (!p) { | |
929 | ti->error = "memory allocation failed"; | |
930 | ret = -ENOMEM; | |
931 | goto fail; | |
932 | } | |
933 | j = sprintf(p, "%d", hw_argc - 1); | |
934 | for (i = 0, p+=j+1; i <= hw_argc - 2; i++, p+=j+1) | |
935 | j = sprintf(p, "%s", as->argv[i]); | |
936 | } | |
937 | dm_consume_args(as, hw_argc - 1); | |
938 | ||
939 | return 0; | |
940 | fail: | |
941 | kfree(m->hw_handler_name); | |
942 | m->hw_handler_name = NULL; | |
943 | return ret; | |
944 | } | |
945 | ||
946 | static int parse_features(struct dm_arg_set *as, struct multipath *m) | |
947 | { | |
948 | int r; | |
949 | unsigned argc; | |
950 | struct dm_target *ti = m->ti; | |
951 | const char *arg_name; | |
952 | ||
953 | static struct dm_arg _args[] = { | |
954 | {0, 8, "invalid number of feature args"}, | |
955 | {1, 50, "pg_init_retries must be between 1 and 50"}, | |
956 | {0, 60000, "pg_init_delay_msecs must be between 0 and 60000"}, | |
957 | }; | |
958 | ||
959 | r = dm_read_arg_group(_args, as, &argc, &ti->error); | |
960 | if (r) | |
961 | return -EINVAL; | |
962 | ||
963 | if (!argc) | |
964 | return 0; | |
965 | ||
966 | do { | |
967 | arg_name = dm_shift_arg(as); | |
968 | argc--; | |
969 | ||
970 | if (!strcasecmp(arg_name, "queue_if_no_path")) { | |
971 | r = queue_if_no_path(m, true, false); | |
972 | continue; | |
973 | } | |
974 | ||
975 | if (!strcasecmp(arg_name, "retain_attached_hw_handler")) { | |
976 | set_bit(MPATHF_RETAIN_ATTACHED_HW_HANDLER, &m->flags); | |
977 | continue; | |
978 | } | |
979 | ||
980 | if (!strcasecmp(arg_name, "pg_init_retries") && | |
981 | (argc >= 1)) { | |
982 | r = dm_read_arg(_args + 1, as, &m->pg_init_retries, &ti->error); | |
983 | argc--; | |
984 | continue; | |
985 | } | |
986 | ||
987 | if (!strcasecmp(arg_name, "pg_init_delay_msecs") && | |
988 | (argc >= 1)) { | |
989 | r = dm_read_arg(_args + 2, as, &m->pg_init_delay_msecs, &ti->error); | |
990 | argc--; | |
991 | continue; | |
992 | } | |
993 | ||
994 | if (!strcasecmp(arg_name, "queue_mode") && | |
995 | (argc >= 1)) { | |
996 | const char *queue_mode_name = dm_shift_arg(as); | |
997 | ||
998 | if (!strcasecmp(queue_mode_name, "bio")) | |
999 | m->queue_mode = DM_TYPE_BIO_BASED; | |
1000 | else if (!strcasecmp(queue_mode_name, "rq")) | |
1001 | m->queue_mode = DM_TYPE_REQUEST_BASED; | |
1002 | else if (!strcasecmp(queue_mode_name, "mq")) | |
1003 | m->queue_mode = DM_TYPE_MQ_REQUEST_BASED; | |
1004 | else { | |
1005 | ti->error = "Unknown 'queue_mode' requested"; | |
1006 | r = -EINVAL; | |
1007 | } | |
1008 | argc--; | |
1009 | continue; | |
1010 | } | |
1011 | ||
1012 | ti->error = "Unrecognised multipath feature request"; | |
1013 | r = -EINVAL; | |
1014 | } while (argc && !r); | |
1015 | ||
1016 | return r; | |
1017 | } | |
1018 | ||
1019 | static int multipath_ctr(struct dm_target *ti, unsigned argc, char **argv) | |
1020 | { | |
1021 | /* target arguments */ | |
1022 | static struct dm_arg _args[] = { | |
1023 | {0, 1024, "invalid number of priority groups"}, | |
1024 | {0, 1024, "invalid initial priority group number"}, | |
1025 | }; | |
1026 | ||
1027 | int r; | |
1028 | struct multipath *m; | |
1029 | struct dm_arg_set as; | |
1030 | unsigned pg_count = 0; | |
1031 | unsigned next_pg_num; | |
1032 | ||
1033 | as.argc = argc; | |
1034 | as.argv = argv; | |
1035 | ||
1036 | m = alloc_multipath(ti); | |
1037 | if (!m) { | |
1038 | ti->error = "can't allocate multipath"; | |
1039 | return -EINVAL; | |
1040 | } | |
1041 | ||
1042 | r = parse_features(&as, m); | |
1043 | if (r) | |
1044 | goto bad; | |
1045 | ||
1046 | r = alloc_multipath_stage2(ti, m); | |
1047 | if (r) | |
1048 | goto bad; | |
1049 | ||
1050 | r = parse_hw_handler(&as, m); | |
1051 | if (r) | |
1052 | goto bad; | |
1053 | ||
1054 | r = dm_read_arg(_args, &as, &m->nr_priority_groups, &ti->error); | |
1055 | if (r) | |
1056 | goto bad; | |
1057 | ||
1058 | r = dm_read_arg(_args + 1, &as, &next_pg_num, &ti->error); | |
1059 | if (r) | |
1060 | goto bad; | |
1061 | ||
1062 | if ((!m->nr_priority_groups && next_pg_num) || | |
1063 | (m->nr_priority_groups && !next_pg_num)) { | |
1064 | ti->error = "invalid initial priority group"; | |
1065 | r = -EINVAL; | |
1066 | goto bad; | |
1067 | } | |
1068 | ||
1069 | /* parse the priority groups */ | |
1070 | while (as.argc) { | |
1071 | struct priority_group *pg; | |
1072 | unsigned nr_valid_paths = atomic_read(&m->nr_valid_paths); | |
1073 | ||
1074 | pg = parse_priority_group(&as, m); | |
1075 | if (IS_ERR(pg)) { | |
1076 | r = PTR_ERR(pg); | |
1077 | goto bad; | |
1078 | } | |
1079 | ||
1080 | nr_valid_paths += pg->nr_pgpaths; | |
1081 | atomic_set(&m->nr_valid_paths, nr_valid_paths); | |
1082 | ||
1083 | list_add_tail(&pg->list, &m->priority_groups); | |
1084 | pg_count++; | |
1085 | pg->pg_num = pg_count; | |
1086 | if (!--next_pg_num) | |
1087 | m->next_pg = pg; | |
1088 | } | |
1089 | ||
1090 | if (pg_count != m->nr_priority_groups) { | |
1091 | ti->error = "priority group count mismatch"; | |
1092 | r = -EINVAL; | |
1093 | goto bad; | |
1094 | } | |
1095 | ||
1096 | ti->num_flush_bios = 1; | |
1097 | ti->num_discard_bios = 1; | |
1098 | ti->num_write_same_bios = 1; | |
1099 | ti->num_write_zeroes_bios = 1; | |
1100 | if (m->queue_mode == DM_TYPE_BIO_BASED) | |
1101 | ti->per_io_data_size = multipath_per_bio_data_size(); | |
1102 | else | |
1103 | ti->per_io_data_size = sizeof(struct dm_mpath_io); | |
1104 | ||
1105 | return 0; | |
1106 | ||
1107 | bad: | |
1108 | free_multipath(m); | |
1109 | return r; | |
1110 | } | |
1111 | ||
1112 | static void multipath_wait_for_pg_init_completion(struct multipath *m) | |
1113 | { | |
1114 | DEFINE_WAIT(wait); | |
1115 | ||
1116 | while (1) { | |
1117 | prepare_to_wait(&m->pg_init_wait, &wait, TASK_UNINTERRUPTIBLE); | |
1118 | ||
1119 | if (!atomic_read(&m->pg_init_in_progress)) | |
1120 | break; | |
1121 | ||
1122 | io_schedule(); | |
1123 | } | |
1124 | finish_wait(&m->pg_init_wait, &wait); | |
1125 | } | |
1126 | ||
1127 | static void flush_multipath_work(struct multipath *m) | |
1128 | { | |
1129 | set_bit(MPATHF_PG_INIT_DISABLED, &m->flags); | |
1130 | smp_mb__after_atomic(); | |
1131 | ||
1132 | flush_workqueue(kmpath_handlerd); | |
1133 | multipath_wait_for_pg_init_completion(m); | |
1134 | flush_workqueue(kmultipathd); | |
1135 | flush_work(&m->trigger_event); | |
1136 | ||
1137 | clear_bit(MPATHF_PG_INIT_DISABLED, &m->flags); | |
1138 | smp_mb__after_atomic(); | |
1139 | } | |
1140 | ||
1141 | static void multipath_dtr(struct dm_target *ti) | |
1142 | { | |
1143 | struct multipath *m = ti->private; | |
1144 | ||
1145 | flush_multipath_work(m); | |
1146 | free_multipath(m); | |
1147 | } | |
1148 | ||
1149 | /* | |
1150 | * Take a path out of use. | |
1151 | */ | |
1152 | static int fail_path(struct pgpath *pgpath) | |
1153 | { | |
1154 | unsigned long flags; | |
1155 | struct multipath *m = pgpath->pg->m; | |
1156 | ||
1157 | spin_lock_irqsave(&m->lock, flags); | |
1158 | ||
1159 | if (!pgpath->is_active) | |
1160 | goto out; | |
1161 | ||
1162 | DMWARN("Failing path %s.", pgpath->path.dev->name); | |
1163 | ||
1164 | pgpath->pg->ps.type->fail_path(&pgpath->pg->ps, &pgpath->path); | |
1165 | pgpath->is_active = false; | |
1166 | pgpath->fail_count++; | |
1167 | ||
1168 | atomic_dec(&m->nr_valid_paths); | |
1169 | ||
1170 | if (pgpath == m->current_pgpath) | |
1171 | m->current_pgpath = NULL; | |
1172 | ||
1173 | dm_path_uevent(DM_UEVENT_PATH_FAILED, m->ti, | |
1174 | pgpath->path.dev->name, atomic_read(&m->nr_valid_paths)); | |
1175 | ||
1176 | schedule_work(&m->trigger_event); | |
1177 | ||
1178 | out: | |
1179 | spin_unlock_irqrestore(&m->lock, flags); | |
1180 | ||
1181 | return 0; | |
1182 | } | |
1183 | ||
1184 | /* | |
1185 | * Reinstate a previously-failed path | |
1186 | */ | |
1187 | static int reinstate_path(struct pgpath *pgpath) | |
1188 | { | |
1189 | int r = 0, run_queue = 0; | |
1190 | unsigned long flags; | |
1191 | struct multipath *m = pgpath->pg->m; | |
1192 | unsigned nr_valid_paths; | |
1193 | ||
1194 | spin_lock_irqsave(&m->lock, flags); | |
1195 | ||
1196 | if (pgpath->is_active) | |
1197 | goto out; | |
1198 | ||
1199 | DMWARN("Reinstating path %s.", pgpath->path.dev->name); | |
1200 | ||
1201 | r = pgpath->pg->ps.type->reinstate_path(&pgpath->pg->ps, &pgpath->path); | |
1202 | if (r) | |
1203 | goto out; | |
1204 | ||
1205 | pgpath->is_active = true; | |
1206 | ||
1207 | nr_valid_paths = atomic_inc_return(&m->nr_valid_paths); | |
1208 | if (nr_valid_paths == 1) { | |
1209 | m->current_pgpath = NULL; | |
1210 | run_queue = 1; | |
1211 | } else if (m->hw_handler_name && (m->current_pg == pgpath->pg)) { | |
1212 | if (queue_work(kmpath_handlerd, &pgpath->activate_path.work)) | |
1213 | atomic_inc(&m->pg_init_in_progress); | |
1214 | } | |
1215 | ||
1216 | dm_path_uevent(DM_UEVENT_PATH_REINSTATED, m->ti, | |
1217 | pgpath->path.dev->name, nr_valid_paths); | |
1218 | ||
1219 | schedule_work(&m->trigger_event); | |
1220 | ||
1221 | out: | |
1222 | spin_unlock_irqrestore(&m->lock, flags); | |
1223 | if (run_queue) { | |
1224 | dm_table_run_md_queue_async(m->ti->table); | |
1225 | process_queued_io_list(m); | |
1226 | } | |
1227 | ||
1228 | return r; | |
1229 | } | |
1230 | ||
1231 | /* | |
1232 | * Fail or reinstate all paths that match the provided struct dm_dev. | |
1233 | */ | |
1234 | static int action_dev(struct multipath *m, struct dm_dev *dev, | |
1235 | action_fn action) | |
1236 | { | |
1237 | int r = -EINVAL; | |
1238 | struct pgpath *pgpath; | |
1239 | struct priority_group *pg; | |
1240 | ||
1241 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1242 | list_for_each_entry(pgpath, &pg->pgpaths, list) { | |
1243 | if (pgpath->path.dev == dev) | |
1244 | r = action(pgpath); | |
1245 | } | |
1246 | } | |
1247 | ||
1248 | return r; | |
1249 | } | |
1250 | ||
1251 | /* | |
1252 | * Temporarily try to avoid having to use the specified PG | |
1253 | */ | |
1254 | static void bypass_pg(struct multipath *m, struct priority_group *pg, | |
1255 | bool bypassed) | |
1256 | { | |
1257 | unsigned long flags; | |
1258 | ||
1259 | spin_lock_irqsave(&m->lock, flags); | |
1260 | ||
1261 | pg->bypassed = bypassed; | |
1262 | m->current_pgpath = NULL; | |
1263 | m->current_pg = NULL; | |
1264 | ||
1265 | spin_unlock_irqrestore(&m->lock, flags); | |
1266 | ||
1267 | schedule_work(&m->trigger_event); | |
1268 | } | |
1269 | ||
1270 | /* | |
1271 | * Switch to using the specified PG from the next I/O that gets mapped | |
1272 | */ | |
1273 | static int switch_pg_num(struct multipath *m, const char *pgstr) | |
1274 | { | |
1275 | struct priority_group *pg; | |
1276 | unsigned pgnum; | |
1277 | unsigned long flags; | |
1278 | char dummy; | |
1279 | ||
1280 | if (!pgstr || (sscanf(pgstr, "%u%c", &pgnum, &dummy) != 1) || !pgnum || | |
1281 | !m->nr_priority_groups || (pgnum > m->nr_priority_groups)) { | |
1282 | DMWARN("invalid PG number supplied to switch_pg_num"); | |
1283 | return -EINVAL; | |
1284 | } | |
1285 | ||
1286 | spin_lock_irqsave(&m->lock, flags); | |
1287 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1288 | pg->bypassed = false; | |
1289 | if (--pgnum) | |
1290 | continue; | |
1291 | ||
1292 | m->current_pgpath = NULL; | |
1293 | m->current_pg = NULL; | |
1294 | m->next_pg = pg; | |
1295 | } | |
1296 | spin_unlock_irqrestore(&m->lock, flags); | |
1297 | ||
1298 | schedule_work(&m->trigger_event); | |
1299 | return 0; | |
1300 | } | |
1301 | ||
1302 | /* | |
1303 | * Set/clear bypassed status of a PG. | |
1304 | * PGs are numbered upwards from 1 in the order they were declared. | |
1305 | */ | |
1306 | static int bypass_pg_num(struct multipath *m, const char *pgstr, bool bypassed) | |
1307 | { | |
1308 | struct priority_group *pg; | |
1309 | unsigned pgnum; | |
1310 | char dummy; | |
1311 | ||
1312 | if (!pgstr || (sscanf(pgstr, "%u%c", &pgnum, &dummy) != 1) || !pgnum || | |
1313 | !m->nr_priority_groups || (pgnum > m->nr_priority_groups)) { | |
1314 | DMWARN("invalid PG number supplied to bypass_pg"); | |
1315 | return -EINVAL; | |
1316 | } | |
1317 | ||
1318 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1319 | if (!--pgnum) | |
1320 | break; | |
1321 | } | |
1322 | ||
1323 | bypass_pg(m, pg, bypassed); | |
1324 | return 0; | |
1325 | } | |
1326 | ||
1327 | /* | |
1328 | * Should we retry pg_init immediately? | |
1329 | */ | |
1330 | static bool pg_init_limit_reached(struct multipath *m, struct pgpath *pgpath) | |
1331 | { | |
1332 | unsigned long flags; | |
1333 | bool limit_reached = false; | |
1334 | ||
1335 | spin_lock_irqsave(&m->lock, flags); | |
1336 | ||
1337 | if (atomic_read(&m->pg_init_count) <= m->pg_init_retries && | |
1338 | !test_bit(MPATHF_PG_INIT_DISABLED, &m->flags)) | |
1339 | set_bit(MPATHF_PG_INIT_REQUIRED, &m->flags); | |
1340 | else | |
1341 | limit_reached = true; | |
1342 | ||
1343 | spin_unlock_irqrestore(&m->lock, flags); | |
1344 | ||
1345 | return limit_reached; | |
1346 | } | |
1347 | ||
1348 | static void pg_init_done(void *data, int errors) | |
1349 | { | |
1350 | struct pgpath *pgpath = data; | |
1351 | struct priority_group *pg = pgpath->pg; | |
1352 | struct multipath *m = pg->m; | |
1353 | unsigned long flags; | |
1354 | bool delay_retry = false; | |
1355 | ||
1356 | /* device or driver problems */ | |
1357 | switch (errors) { | |
1358 | case SCSI_DH_OK: | |
1359 | break; | |
1360 | case SCSI_DH_NOSYS: | |
1361 | if (!m->hw_handler_name) { | |
1362 | errors = 0; | |
1363 | break; | |
1364 | } | |
1365 | DMERR("Could not failover the device: Handler scsi_dh_%s " | |
1366 | "Error %d.", m->hw_handler_name, errors); | |
1367 | /* | |
1368 | * Fail path for now, so we do not ping pong | |
1369 | */ | |
1370 | fail_path(pgpath); | |
1371 | break; | |
1372 | case SCSI_DH_DEV_TEMP_BUSY: | |
1373 | /* | |
1374 | * Probably doing something like FW upgrade on the | |
1375 | * controller so try the other pg. | |
1376 | */ | |
1377 | bypass_pg(m, pg, true); | |
1378 | break; | |
1379 | case SCSI_DH_RETRY: | |
1380 | /* Wait before retrying. */ | |
1381 | delay_retry = 1; | |
1382 | case SCSI_DH_IMM_RETRY: | |
1383 | case SCSI_DH_RES_TEMP_UNAVAIL: | |
1384 | if (pg_init_limit_reached(m, pgpath)) | |
1385 | fail_path(pgpath); | |
1386 | errors = 0; | |
1387 | break; | |
1388 | case SCSI_DH_DEV_OFFLINED: | |
1389 | default: | |
1390 | /* | |
1391 | * We probably do not want to fail the path for a device | |
1392 | * error, but this is what the old dm did. In future | |
1393 | * patches we can do more advanced handling. | |
1394 | */ | |
1395 | fail_path(pgpath); | |
1396 | } | |
1397 | ||
1398 | spin_lock_irqsave(&m->lock, flags); | |
1399 | if (errors) { | |
1400 | if (pgpath == m->current_pgpath) { | |
1401 | DMERR("Could not failover device. Error %d.", errors); | |
1402 | m->current_pgpath = NULL; | |
1403 | m->current_pg = NULL; | |
1404 | } | |
1405 | } else if (!test_bit(MPATHF_PG_INIT_REQUIRED, &m->flags)) | |
1406 | pg->bypassed = false; | |
1407 | ||
1408 | if (atomic_dec_return(&m->pg_init_in_progress) > 0) | |
1409 | /* Activations of other paths are still on going */ | |
1410 | goto out; | |
1411 | ||
1412 | if (test_bit(MPATHF_PG_INIT_REQUIRED, &m->flags)) { | |
1413 | if (delay_retry) | |
1414 | set_bit(MPATHF_PG_INIT_DELAY_RETRY, &m->flags); | |
1415 | else | |
1416 | clear_bit(MPATHF_PG_INIT_DELAY_RETRY, &m->flags); | |
1417 | ||
1418 | if (__pg_init_all_paths(m)) | |
1419 | goto out; | |
1420 | } | |
1421 | clear_bit(MPATHF_QUEUE_IO, &m->flags); | |
1422 | ||
1423 | process_queued_io_list(m); | |
1424 | ||
1425 | /* | |
1426 | * Wake up any thread waiting to suspend. | |
1427 | */ | |
1428 | wake_up(&m->pg_init_wait); | |
1429 | ||
1430 | out: | |
1431 | spin_unlock_irqrestore(&m->lock, flags); | |
1432 | } | |
1433 | ||
1434 | static void activate_or_offline_path(struct pgpath *pgpath) | |
1435 | { | |
1436 | struct request_queue *q = bdev_get_queue(pgpath->path.dev->bdev); | |
1437 | ||
1438 | if (pgpath->is_active && !blk_queue_dying(q)) | |
1439 | scsi_dh_activate(q, pg_init_done, pgpath); | |
1440 | else | |
1441 | pg_init_done(pgpath, SCSI_DH_DEV_OFFLINED); | |
1442 | } | |
1443 | ||
1444 | static void activate_path_work(struct work_struct *work) | |
1445 | { | |
1446 | struct pgpath *pgpath = | |
1447 | container_of(work, struct pgpath, activate_path.work); | |
1448 | ||
1449 | activate_or_offline_path(pgpath); | |
1450 | } | |
1451 | ||
1452 | static int noretry_error(blk_status_t error) | |
1453 | { | |
1454 | switch (error) { | |
1455 | case BLK_STS_NOTSUPP: | |
1456 | case BLK_STS_NOSPC: | |
1457 | case BLK_STS_TARGET: | |
1458 | case BLK_STS_NEXUS: | |
1459 | case BLK_STS_MEDIUM: | |
1460 | return 1; | |
1461 | } | |
1462 | ||
1463 | /* Anything else could be a path failure, so should be retried */ | |
1464 | return 0; | |
1465 | } | |
1466 | ||
1467 | static int multipath_end_io(struct dm_target *ti, struct request *clone, | |
1468 | blk_status_t error, union map_info *map_context) | |
1469 | { | |
1470 | struct dm_mpath_io *mpio = get_mpio(map_context); | |
1471 | struct pgpath *pgpath = mpio->pgpath; | |
1472 | int r = DM_ENDIO_DONE; | |
1473 | ||
1474 | /* | |
1475 | * We don't queue any clone request inside the multipath target | |
1476 | * during end I/O handling, since those clone requests don't have | |
1477 | * bio clones. If we queue them inside the multipath target, | |
1478 | * we need to make bio clones, that requires memory allocation. | |
1479 | * (See drivers/md/dm-rq.c:end_clone_bio() about why the clone requests | |
1480 | * don't have bio clones.) | |
1481 | * Instead of queueing the clone request here, we queue the original | |
1482 | * request into dm core, which will remake a clone request and | |
1483 | * clone bios for it and resubmit it later. | |
1484 | */ | |
1485 | if (error && !noretry_error(error)) { | |
1486 | struct multipath *m = ti->private; | |
1487 | ||
1488 | r = DM_ENDIO_REQUEUE; | |
1489 | ||
1490 | if (pgpath) | |
1491 | fail_path(pgpath); | |
1492 | ||
1493 | if (atomic_read(&m->nr_valid_paths) == 0 && | |
1494 | !test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) { | |
1495 | if (error == BLK_STS_IOERR) | |
1496 | dm_report_EIO(m); | |
1497 | /* complete with the original error */ | |
1498 | r = DM_ENDIO_DONE; | |
1499 | } | |
1500 | } | |
1501 | ||
1502 | if (pgpath) { | |
1503 | struct path_selector *ps = &pgpath->pg->ps; | |
1504 | ||
1505 | if (ps->type->end_io) | |
1506 | ps->type->end_io(ps, &pgpath->path, mpio->nr_bytes); | |
1507 | } | |
1508 | ||
1509 | return r; | |
1510 | } | |
1511 | ||
1512 | static int multipath_end_io_bio(struct dm_target *ti, struct bio *clone, | |
1513 | blk_status_t *error) | |
1514 | { | |
1515 | struct multipath *m = ti->private; | |
1516 | struct dm_mpath_io *mpio = get_mpio_from_bio(clone); | |
1517 | struct pgpath *pgpath = mpio->pgpath; | |
1518 | unsigned long flags; | |
1519 | int r = DM_ENDIO_DONE; | |
1520 | ||
1521 | if (!*error || noretry_error(*error)) | |
1522 | goto done; | |
1523 | ||
1524 | if (pgpath) | |
1525 | fail_path(pgpath); | |
1526 | ||
1527 | if (atomic_read(&m->nr_valid_paths) == 0 && | |
1528 | !test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) { | |
1529 | dm_report_EIO(m); | |
1530 | *error = BLK_STS_IOERR; | |
1531 | goto done; | |
1532 | } | |
1533 | ||
1534 | /* Queue for the daemon to resubmit */ | |
1535 | dm_bio_restore(get_bio_details_from_bio(clone), clone); | |
1536 | ||
1537 | spin_lock_irqsave(&m->lock, flags); | |
1538 | bio_list_add(&m->queued_bios, clone); | |
1539 | spin_unlock_irqrestore(&m->lock, flags); | |
1540 | if (!test_bit(MPATHF_QUEUE_IO, &m->flags)) | |
1541 | queue_work(kmultipathd, &m->process_queued_bios); | |
1542 | ||
1543 | r = DM_ENDIO_INCOMPLETE; | |
1544 | done: | |
1545 | if (pgpath) { | |
1546 | struct path_selector *ps = &pgpath->pg->ps; | |
1547 | ||
1548 | if (ps->type->end_io) | |
1549 | ps->type->end_io(ps, &pgpath->path, mpio->nr_bytes); | |
1550 | } | |
1551 | ||
1552 | return r; | |
1553 | } | |
1554 | ||
1555 | /* | |
1556 | * Suspend can't complete until all the I/O is processed so if | |
1557 | * the last path fails we must error any remaining I/O. | |
1558 | * Note that if the freeze_bdev fails while suspending, the | |
1559 | * queue_if_no_path state is lost - userspace should reset it. | |
1560 | */ | |
1561 | static void multipath_presuspend(struct dm_target *ti) | |
1562 | { | |
1563 | struct multipath *m = ti->private; | |
1564 | ||
1565 | queue_if_no_path(m, false, true); | |
1566 | } | |
1567 | ||
1568 | static void multipath_postsuspend(struct dm_target *ti) | |
1569 | { | |
1570 | struct multipath *m = ti->private; | |
1571 | ||
1572 | mutex_lock(&m->work_mutex); | |
1573 | flush_multipath_work(m); | |
1574 | mutex_unlock(&m->work_mutex); | |
1575 | } | |
1576 | ||
1577 | /* | |
1578 | * Restore the queue_if_no_path setting. | |
1579 | */ | |
1580 | static void multipath_resume(struct dm_target *ti) | |
1581 | { | |
1582 | struct multipath *m = ti->private; | |
1583 | unsigned long flags; | |
1584 | ||
1585 | spin_lock_irqsave(&m->lock, flags); | |
1586 | assign_bit(test_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &m->flags), | |
1587 | MPATHF_QUEUE_IF_NO_PATH, &m->flags); | |
1588 | spin_unlock_irqrestore(&m->lock, flags); | |
1589 | } | |
1590 | ||
1591 | /* | |
1592 | * Info output has the following format: | |
1593 | * num_multipath_feature_args [multipath_feature_args]* | |
1594 | * num_handler_status_args [handler_status_args]* | |
1595 | * num_groups init_group_number | |
1596 | * [A|D|E num_ps_status_args [ps_status_args]* | |
1597 | * num_paths num_selector_args | |
1598 | * [path_dev A|F fail_count [selector_args]* ]+ ]+ | |
1599 | * | |
1600 | * Table output has the following format (identical to the constructor string): | |
1601 | * num_feature_args [features_args]* | |
1602 | * num_handler_args hw_handler [hw_handler_args]* | |
1603 | * num_groups init_group_number | |
1604 | * [priority selector-name num_ps_args [ps_args]* | |
1605 | * num_paths num_selector_args [path_dev [selector_args]* ]+ ]+ | |
1606 | */ | |
1607 | static void multipath_status(struct dm_target *ti, status_type_t type, | |
1608 | unsigned status_flags, char *result, unsigned maxlen) | |
1609 | { | |
1610 | int sz = 0; | |
1611 | unsigned long flags; | |
1612 | struct multipath *m = ti->private; | |
1613 | struct priority_group *pg; | |
1614 | struct pgpath *p; | |
1615 | unsigned pg_num; | |
1616 | char state; | |
1617 | ||
1618 | spin_lock_irqsave(&m->lock, flags); | |
1619 | ||
1620 | /* Features */ | |
1621 | if (type == STATUSTYPE_INFO) | |
1622 | DMEMIT("2 %u %u ", test_bit(MPATHF_QUEUE_IO, &m->flags), | |
1623 | atomic_read(&m->pg_init_count)); | |
1624 | else { | |
1625 | DMEMIT("%u ", test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags) + | |
1626 | (m->pg_init_retries > 0) * 2 + | |
1627 | (m->pg_init_delay_msecs != DM_PG_INIT_DELAY_DEFAULT) * 2 + | |
1628 | test_bit(MPATHF_RETAIN_ATTACHED_HW_HANDLER, &m->flags) + | |
1629 | (m->queue_mode != DM_TYPE_REQUEST_BASED) * 2); | |
1630 | ||
1631 | if (test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) | |
1632 | DMEMIT("queue_if_no_path "); | |
1633 | if (m->pg_init_retries) | |
1634 | DMEMIT("pg_init_retries %u ", m->pg_init_retries); | |
1635 | if (m->pg_init_delay_msecs != DM_PG_INIT_DELAY_DEFAULT) | |
1636 | DMEMIT("pg_init_delay_msecs %u ", m->pg_init_delay_msecs); | |
1637 | if (test_bit(MPATHF_RETAIN_ATTACHED_HW_HANDLER, &m->flags)) | |
1638 | DMEMIT("retain_attached_hw_handler "); | |
1639 | if (m->queue_mode != DM_TYPE_REQUEST_BASED) { | |
1640 | switch(m->queue_mode) { | |
1641 | case DM_TYPE_BIO_BASED: | |
1642 | DMEMIT("queue_mode bio "); | |
1643 | break; | |
1644 | case DM_TYPE_MQ_REQUEST_BASED: | |
1645 | DMEMIT("queue_mode mq "); | |
1646 | break; | |
1647 | default: | |
1648 | WARN_ON_ONCE(true); | |
1649 | break; | |
1650 | } | |
1651 | } | |
1652 | } | |
1653 | ||
1654 | if (!m->hw_handler_name || type == STATUSTYPE_INFO) | |
1655 | DMEMIT("0 "); | |
1656 | else | |
1657 | DMEMIT("1 %s ", m->hw_handler_name); | |
1658 | ||
1659 | DMEMIT("%u ", m->nr_priority_groups); | |
1660 | ||
1661 | if (m->next_pg) | |
1662 | pg_num = m->next_pg->pg_num; | |
1663 | else if (m->current_pg) | |
1664 | pg_num = m->current_pg->pg_num; | |
1665 | else | |
1666 | pg_num = (m->nr_priority_groups ? 1 : 0); | |
1667 | ||
1668 | DMEMIT("%u ", pg_num); | |
1669 | ||
1670 | switch (type) { | |
1671 | case STATUSTYPE_INFO: | |
1672 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1673 | if (pg->bypassed) | |
1674 | state = 'D'; /* Disabled */ | |
1675 | else if (pg == m->current_pg) | |
1676 | state = 'A'; /* Currently Active */ | |
1677 | else | |
1678 | state = 'E'; /* Enabled */ | |
1679 | ||
1680 | DMEMIT("%c ", state); | |
1681 | ||
1682 | if (pg->ps.type->status) | |
1683 | sz += pg->ps.type->status(&pg->ps, NULL, type, | |
1684 | result + sz, | |
1685 | maxlen - sz); | |
1686 | else | |
1687 | DMEMIT("0 "); | |
1688 | ||
1689 | DMEMIT("%u %u ", pg->nr_pgpaths, | |
1690 | pg->ps.type->info_args); | |
1691 | ||
1692 | list_for_each_entry(p, &pg->pgpaths, list) { | |
1693 | DMEMIT("%s %s %u ", p->path.dev->name, | |
1694 | p->is_active ? "A" : "F", | |
1695 | p->fail_count); | |
1696 | if (pg->ps.type->status) | |
1697 | sz += pg->ps.type->status(&pg->ps, | |
1698 | &p->path, type, result + sz, | |
1699 | maxlen - sz); | |
1700 | } | |
1701 | } | |
1702 | break; | |
1703 | ||
1704 | case STATUSTYPE_TABLE: | |
1705 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1706 | DMEMIT("%s ", pg->ps.type->name); | |
1707 | ||
1708 | if (pg->ps.type->status) | |
1709 | sz += pg->ps.type->status(&pg->ps, NULL, type, | |
1710 | result + sz, | |
1711 | maxlen - sz); | |
1712 | else | |
1713 | DMEMIT("0 "); | |
1714 | ||
1715 | DMEMIT("%u %u ", pg->nr_pgpaths, | |
1716 | pg->ps.type->table_args); | |
1717 | ||
1718 | list_for_each_entry(p, &pg->pgpaths, list) { | |
1719 | DMEMIT("%s ", p->path.dev->name); | |
1720 | if (pg->ps.type->status) | |
1721 | sz += pg->ps.type->status(&pg->ps, | |
1722 | &p->path, type, result + sz, | |
1723 | maxlen - sz); | |
1724 | } | |
1725 | } | |
1726 | break; | |
1727 | } | |
1728 | ||
1729 | spin_unlock_irqrestore(&m->lock, flags); | |
1730 | } | |
1731 | ||
1732 | static int multipath_message(struct dm_target *ti, unsigned argc, char **argv) | |
1733 | { | |
1734 | int r = -EINVAL; | |
1735 | struct dm_dev *dev; | |
1736 | struct multipath *m = ti->private; | |
1737 | action_fn action; | |
1738 | ||
1739 | mutex_lock(&m->work_mutex); | |
1740 | ||
1741 | if (dm_suspended(ti)) { | |
1742 | r = -EBUSY; | |
1743 | goto out; | |
1744 | } | |
1745 | ||
1746 | if (argc == 1) { | |
1747 | if (!strcasecmp(argv[0], "queue_if_no_path")) { | |
1748 | r = queue_if_no_path(m, true, false); | |
1749 | goto out; | |
1750 | } else if (!strcasecmp(argv[0], "fail_if_no_path")) { | |
1751 | r = queue_if_no_path(m, false, false); | |
1752 | goto out; | |
1753 | } | |
1754 | } | |
1755 | ||
1756 | if (argc != 2) { | |
1757 | DMWARN("Invalid multipath message arguments. Expected 2 arguments, got %d.", argc); | |
1758 | goto out; | |
1759 | } | |
1760 | ||
1761 | if (!strcasecmp(argv[0], "disable_group")) { | |
1762 | r = bypass_pg_num(m, argv[1], true); | |
1763 | goto out; | |
1764 | } else if (!strcasecmp(argv[0], "enable_group")) { | |
1765 | r = bypass_pg_num(m, argv[1], false); | |
1766 | goto out; | |
1767 | } else if (!strcasecmp(argv[0], "switch_group")) { | |
1768 | r = switch_pg_num(m, argv[1]); | |
1769 | goto out; | |
1770 | } else if (!strcasecmp(argv[0], "reinstate_path")) | |
1771 | action = reinstate_path; | |
1772 | else if (!strcasecmp(argv[0], "fail_path")) | |
1773 | action = fail_path; | |
1774 | else { | |
1775 | DMWARN("Unrecognised multipath message received: %s", argv[0]); | |
1776 | goto out; | |
1777 | } | |
1778 | ||
1779 | r = dm_get_device(ti, argv[1], dm_table_get_mode(ti->table), &dev); | |
1780 | if (r) { | |
1781 | DMWARN("message: error getting device %s", | |
1782 | argv[1]); | |
1783 | goto out; | |
1784 | } | |
1785 | ||
1786 | r = action_dev(m, dev, action); | |
1787 | ||
1788 | dm_put_device(ti, dev); | |
1789 | ||
1790 | out: | |
1791 | mutex_unlock(&m->work_mutex); | |
1792 | return r; | |
1793 | } | |
1794 | ||
1795 | static int multipath_prepare_ioctl(struct dm_target *ti, | |
1796 | struct block_device **bdev, fmode_t *mode) | |
1797 | { | |
1798 | struct multipath *m = ti->private; | |
1799 | struct pgpath *current_pgpath; | |
1800 | int r; | |
1801 | ||
1802 | current_pgpath = READ_ONCE(m->current_pgpath); | |
1803 | if (!current_pgpath) | |
1804 | current_pgpath = choose_pgpath(m, 0); | |
1805 | ||
1806 | if (current_pgpath) { | |
1807 | if (!test_bit(MPATHF_QUEUE_IO, &m->flags)) { | |
1808 | *bdev = current_pgpath->path.dev->bdev; | |
1809 | *mode = current_pgpath->path.dev->mode; | |
1810 | r = 0; | |
1811 | } else { | |
1812 | /* pg_init has not started or completed */ | |
1813 | r = -ENOTCONN; | |
1814 | } | |
1815 | } else { | |
1816 | /* No path is available */ | |
1817 | if (test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) | |
1818 | r = -ENOTCONN; | |
1819 | else | |
1820 | r = -EIO; | |
1821 | } | |
1822 | ||
1823 | if (r == -ENOTCONN) { | |
1824 | if (!READ_ONCE(m->current_pg)) { | |
1825 | /* Path status changed, redo selection */ | |
1826 | (void) choose_pgpath(m, 0); | |
1827 | } | |
1828 | if (test_bit(MPATHF_PG_INIT_REQUIRED, &m->flags)) | |
1829 | pg_init_all_paths(m); | |
1830 | dm_table_run_md_queue_async(m->ti->table); | |
1831 | process_queued_io_list(m); | |
1832 | } | |
1833 | ||
1834 | /* | |
1835 | * Only pass ioctls through if the device sizes match exactly. | |
1836 | */ | |
1837 | if (!r && ti->len != i_size_read((*bdev)->bd_inode) >> SECTOR_SHIFT) | |
1838 | return 1; | |
1839 | return r; | |
1840 | } | |
1841 | ||
1842 | static int multipath_iterate_devices(struct dm_target *ti, | |
1843 | iterate_devices_callout_fn fn, void *data) | |
1844 | { | |
1845 | struct multipath *m = ti->private; | |
1846 | struct priority_group *pg; | |
1847 | struct pgpath *p; | |
1848 | int ret = 0; | |
1849 | ||
1850 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1851 | list_for_each_entry(p, &pg->pgpaths, list) { | |
1852 | ret = fn(ti, p->path.dev, ti->begin, ti->len, data); | |
1853 | if (ret) | |
1854 | goto out; | |
1855 | } | |
1856 | } | |
1857 | ||
1858 | out: | |
1859 | return ret; | |
1860 | } | |
1861 | ||
1862 | static int pgpath_busy(struct pgpath *pgpath) | |
1863 | { | |
1864 | struct request_queue *q = bdev_get_queue(pgpath->path.dev->bdev); | |
1865 | ||
1866 | return blk_lld_busy(q); | |
1867 | } | |
1868 | ||
1869 | /* | |
1870 | * We return "busy", only when we can map I/Os but underlying devices | |
1871 | * are busy (so even if we map I/Os now, the I/Os will wait on | |
1872 | * the underlying queue). | |
1873 | * In other words, if we want to kill I/Os or queue them inside us | |
1874 | * due to map unavailability, we don't return "busy". Otherwise, | |
1875 | * dm core won't give us the I/Os and we can't do what we want. | |
1876 | */ | |
1877 | static int multipath_busy(struct dm_target *ti) | |
1878 | { | |
1879 | bool busy = false, has_active = false; | |
1880 | struct multipath *m = ti->private; | |
1881 | struct priority_group *pg, *next_pg; | |
1882 | struct pgpath *pgpath; | |
1883 | ||
1884 | /* pg_init in progress */ | |
1885 | if (atomic_read(&m->pg_init_in_progress)) | |
1886 | return true; | |
1887 | ||
1888 | /* no paths available, for blk-mq: rely on IO mapping to delay requeue */ | |
1889 | if (!atomic_read(&m->nr_valid_paths) && test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) | |
1890 | return (m->queue_mode != DM_TYPE_MQ_REQUEST_BASED); | |
1891 | ||
1892 | /* Guess which priority_group will be used at next mapping time */ | |
1893 | pg = READ_ONCE(m->current_pg); | |
1894 | next_pg = READ_ONCE(m->next_pg); | |
1895 | if (unlikely(!READ_ONCE(m->current_pgpath) && next_pg)) | |
1896 | pg = next_pg; | |
1897 | ||
1898 | if (!pg) { | |
1899 | /* | |
1900 | * We don't know which pg will be used at next mapping time. | |
1901 | * We don't call choose_pgpath() here to avoid to trigger | |
1902 | * pg_init just by busy checking. | |
1903 | * So we don't know whether underlying devices we will be using | |
1904 | * at next mapping time are busy or not. Just try mapping. | |
1905 | */ | |
1906 | return busy; | |
1907 | } | |
1908 | ||
1909 | /* | |
1910 | * If there is one non-busy active path at least, the path selector | |
1911 | * will be able to select it. So we consider such a pg as not busy. | |
1912 | */ | |
1913 | busy = true; | |
1914 | list_for_each_entry(pgpath, &pg->pgpaths, list) { | |
1915 | if (pgpath->is_active) { | |
1916 | has_active = true; | |
1917 | if (!pgpath_busy(pgpath)) { | |
1918 | busy = false; | |
1919 | break; | |
1920 | } | |
1921 | } | |
1922 | } | |
1923 | ||
1924 | if (!has_active) { | |
1925 | /* | |
1926 | * No active path in this pg, so this pg won't be used and | |
1927 | * the current_pg will be changed at next mapping time. | |
1928 | * We need to try mapping to determine it. | |
1929 | */ | |
1930 | busy = false; | |
1931 | } | |
1932 | ||
1933 | return busy; | |
1934 | } | |
1935 | ||
1936 | /*----------------------------------------------------------------- | |
1937 | * Module setup | |
1938 | *---------------------------------------------------------------*/ | |
1939 | static struct target_type multipath_target = { | |
1940 | .name = "multipath", | |
1941 | .version = {1, 12, 0}, | |
1942 | .features = DM_TARGET_SINGLETON | DM_TARGET_IMMUTABLE, | |
1943 | .module = THIS_MODULE, | |
1944 | .ctr = multipath_ctr, | |
1945 | .dtr = multipath_dtr, | |
1946 | .clone_and_map_rq = multipath_clone_and_map, | |
1947 | .release_clone_rq = multipath_release_clone, | |
1948 | .rq_end_io = multipath_end_io, | |
1949 | .map = multipath_map_bio, | |
1950 | .end_io = multipath_end_io_bio, | |
1951 | .presuspend = multipath_presuspend, | |
1952 | .postsuspend = multipath_postsuspend, | |
1953 | .resume = multipath_resume, | |
1954 | .status = multipath_status, | |
1955 | .message = multipath_message, | |
1956 | .prepare_ioctl = multipath_prepare_ioctl, | |
1957 | .iterate_devices = multipath_iterate_devices, | |
1958 | .busy = multipath_busy, | |
1959 | }; | |
1960 | ||
1961 | static int __init dm_multipath_init(void) | |
1962 | { | |
1963 | int r; | |
1964 | ||
1965 | r = dm_register_target(&multipath_target); | |
1966 | if (r < 0) { | |
1967 | DMERR("request-based register failed %d", r); | |
1968 | r = -EINVAL; | |
1969 | goto bad_register_target; | |
1970 | } | |
1971 | ||
1972 | kmultipathd = alloc_workqueue("kmpathd", WQ_MEM_RECLAIM, 0); | |
1973 | if (!kmultipathd) { | |
1974 | DMERR("failed to create workqueue kmpathd"); | |
1975 | r = -ENOMEM; | |
1976 | goto bad_alloc_kmultipathd; | |
1977 | } | |
1978 | ||
1979 | /* | |
1980 | * A separate workqueue is used to handle the device handlers | |
1981 | * to avoid overloading existing workqueue. Overloading the | |
1982 | * old workqueue would also create a bottleneck in the | |
1983 | * path of the storage hardware device activation. | |
1984 | */ | |
1985 | kmpath_handlerd = alloc_ordered_workqueue("kmpath_handlerd", | |
1986 | WQ_MEM_RECLAIM); | |
1987 | if (!kmpath_handlerd) { | |
1988 | DMERR("failed to create workqueue kmpath_handlerd"); | |
1989 | r = -ENOMEM; | |
1990 | goto bad_alloc_kmpath_handlerd; | |
1991 | } | |
1992 | ||
1993 | return 0; | |
1994 | ||
1995 | bad_alloc_kmpath_handlerd: | |
1996 | destroy_workqueue(kmultipathd); | |
1997 | bad_alloc_kmultipathd: | |
1998 | dm_unregister_target(&multipath_target); | |
1999 | bad_register_target: | |
2000 | return r; | |
2001 | } | |
2002 | ||
2003 | static void __exit dm_multipath_exit(void) | |
2004 | { | |
2005 | destroy_workqueue(kmpath_handlerd); | |
2006 | destroy_workqueue(kmultipathd); | |
2007 | ||
2008 | dm_unregister_target(&multipath_target); | |
2009 | } | |
2010 | ||
2011 | module_init(dm_multipath_init); | |
2012 | module_exit(dm_multipath_exit); | |
2013 | ||
2014 | MODULE_DESCRIPTION(DM_NAME " multipath target"); | |
2015 | MODULE_AUTHOR("Sistina Software <dm-devel@redhat.com>"); | |
2016 | MODULE_LICENSE("GPL"); |