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> | |
35991652 | 21 | #include <linux/delay.h> |
cfae5c9b | 22 | #include <scsi/scsi_dh.h> |
60063497 | 23 | #include <linux/atomic.h> |
1da177e4 | 24 | |
72d94861 | 25 | #define DM_MSG_PREFIX "multipath" |
4e2d19e4 CS |
26 | #define DM_PG_INIT_DELAY_MSECS 2000 |
27 | #define DM_PG_INIT_DELAY_DEFAULT ((unsigned) -1) | |
1da177e4 LT |
28 | |
29 | /* Path properties */ | |
30 | struct pgpath { | |
31 | struct list_head list; | |
32 | ||
33 | struct priority_group *pg; /* Owning PG */ | |
6680073d | 34 | unsigned is_active; /* Path status */ |
1da177e4 LT |
35 | unsigned fail_count; /* Cumulative failure count */ |
36 | ||
c922d5f7 | 37 | struct dm_path path; |
4e2d19e4 | 38 | struct delayed_work activate_path; |
1da177e4 LT |
39 | }; |
40 | ||
41 | #define path_to_pgpath(__pgp) container_of((__pgp), struct pgpath, path) | |
42 | ||
43 | /* | |
44 | * Paths are grouped into Priority Groups and numbered from 1 upwards. | |
45 | * Each has a path selector which controls which path gets used. | |
46 | */ | |
47 | struct priority_group { | |
48 | struct list_head list; | |
49 | ||
50 | struct multipath *m; /* Owning multipath instance */ | |
51 | struct path_selector ps; | |
52 | ||
53 | unsigned pg_num; /* Reference number */ | |
54 | unsigned bypassed; /* Temporarily bypass this PG? */ | |
55 | ||
56 | unsigned nr_pgpaths; /* Number of paths in PG */ | |
57 | struct list_head pgpaths; | |
58 | }; | |
59 | ||
60 | /* Multipath context */ | |
61 | struct multipath { | |
62 | struct list_head list; | |
63 | struct dm_target *ti; | |
64 | ||
cfae5c9b | 65 | const char *hw_handler_name; |
2bfd2e13 | 66 | char *hw_handler_params; |
4e2d19e4 | 67 | |
1fbdd2b3 MS |
68 | spinlock_t lock; |
69 | ||
1da177e4 LT |
70 | unsigned nr_priority_groups; |
71 | struct list_head priority_groups; | |
4e2d19e4 CS |
72 | |
73 | wait_queue_head_t pg_init_wait; /* Wait for pg_init completion */ | |
74 | ||
1da177e4 | 75 | unsigned pg_init_required; /* pg_init needs calling? */ |
c3cd4f6b | 76 | unsigned pg_init_in_progress; /* Only one pg_init allowed at once */ |
4e2d19e4 | 77 | unsigned pg_init_delay_retry; /* Delay pg_init retry? */ |
1da177e4 LT |
78 | |
79 | unsigned nr_valid_paths; /* Total number of usable paths */ | |
80 | struct pgpath *current_pgpath; | |
81 | struct priority_group *current_pg; | |
82 | struct priority_group *next_pg; /* Switch to this PG if set */ | |
83 | unsigned repeat_count; /* I/Os left before calling PS again */ | |
84 | ||
1fbdd2b3 MS |
85 | unsigned queue_io:1; /* Must we queue all I/O? */ |
86 | unsigned queue_if_no_path:1; /* Queue I/O if last path fails? */ | |
87 | unsigned saved_queue_if_no_path:1; /* Saved state during suspension */ | |
88 | ||
c9e45581 DW |
89 | unsigned pg_init_retries; /* Number of times to retry pg_init */ |
90 | unsigned pg_init_count; /* Number of times pg_init called */ | |
4e2d19e4 | 91 | unsigned pg_init_delay_msecs; /* Number of msecs before pg_init retry */ |
1da177e4 | 92 | |
1fbdd2b3 | 93 | unsigned queue_size; |
1da177e4 | 94 | struct work_struct process_queued_ios; |
f40c67f0 | 95 | struct list_head queued_ios; |
1da177e4 LT |
96 | |
97 | struct work_struct trigger_event; | |
98 | ||
99 | /* | |
028867ac | 100 | * We must use a mempool of dm_mpath_io structs so that we |
1da177e4 LT |
101 | * can resubmit bios on error. |
102 | */ | |
103 | mempool_t *mpio_pool; | |
6380f26f MA |
104 | |
105 | struct mutex work_mutex; | |
1da177e4 LT |
106 | }; |
107 | ||
108 | /* | |
109 | * Context information attached to each bio we process. | |
110 | */ | |
028867ac | 111 | struct dm_mpath_io { |
1da177e4 | 112 | struct pgpath *pgpath; |
02ab823f | 113 | size_t nr_bytes; |
1da177e4 LT |
114 | }; |
115 | ||
116 | typedef int (*action_fn) (struct pgpath *pgpath); | |
117 | ||
118 | #define MIN_IOS 256 /* Mempool size */ | |
119 | ||
e18b890b | 120 | static struct kmem_cache *_mpio_cache; |
1da177e4 | 121 | |
bab7cfc7 | 122 | static struct workqueue_struct *kmultipathd, *kmpath_handlerd; |
c4028958 DH |
123 | static void process_queued_ios(struct work_struct *work); |
124 | static void trigger_event(struct work_struct *work); | |
bab7cfc7 | 125 | static void activate_path(struct work_struct *work); |
1da177e4 LT |
126 | |
127 | ||
128 | /*----------------------------------------------- | |
129 | * Allocation routines | |
130 | *-----------------------------------------------*/ | |
131 | ||
132 | static struct pgpath *alloc_pgpath(void) | |
133 | { | |
e69fae56 | 134 | struct pgpath *pgpath = kzalloc(sizeof(*pgpath), GFP_KERNEL); |
1da177e4 | 135 | |
224cb3e9 | 136 | if (pgpath) { |
6680073d | 137 | pgpath->is_active = 1; |
4e2d19e4 | 138 | INIT_DELAYED_WORK(&pgpath->activate_path, activate_path); |
224cb3e9 | 139 | } |
1da177e4 LT |
140 | |
141 | return pgpath; | |
142 | } | |
143 | ||
028867ac | 144 | static void free_pgpath(struct pgpath *pgpath) |
1da177e4 LT |
145 | { |
146 | kfree(pgpath); | |
147 | } | |
148 | ||
149 | static struct priority_group *alloc_priority_group(void) | |
150 | { | |
151 | struct priority_group *pg; | |
152 | ||
e69fae56 | 153 | pg = kzalloc(sizeof(*pg), GFP_KERNEL); |
1da177e4 | 154 | |
e69fae56 MM |
155 | if (pg) |
156 | INIT_LIST_HEAD(&pg->pgpaths); | |
1da177e4 LT |
157 | |
158 | return pg; | |
159 | } | |
160 | ||
161 | static void free_pgpaths(struct list_head *pgpaths, struct dm_target *ti) | |
162 | { | |
163 | struct pgpath *pgpath, *tmp; | |
ae11b1b3 | 164 | struct multipath *m = ti->private; |
1da177e4 LT |
165 | |
166 | list_for_each_entry_safe(pgpath, tmp, pgpaths, list) { | |
167 | list_del(&pgpath->list); | |
ae11b1b3 HR |
168 | if (m->hw_handler_name) |
169 | scsi_dh_detach(bdev_get_queue(pgpath->path.dev->bdev)); | |
1da177e4 LT |
170 | dm_put_device(ti, pgpath->path.dev); |
171 | free_pgpath(pgpath); | |
172 | } | |
173 | } | |
174 | ||
175 | static void free_priority_group(struct priority_group *pg, | |
176 | struct dm_target *ti) | |
177 | { | |
178 | struct path_selector *ps = &pg->ps; | |
179 | ||
180 | if (ps->type) { | |
181 | ps->type->destroy(ps); | |
182 | dm_put_path_selector(ps->type); | |
183 | } | |
184 | ||
185 | free_pgpaths(&pg->pgpaths, ti); | |
186 | kfree(pg); | |
187 | } | |
188 | ||
28f16c20 | 189 | static struct multipath *alloc_multipath(struct dm_target *ti) |
1da177e4 LT |
190 | { |
191 | struct multipath *m; | |
192 | ||
e69fae56 | 193 | m = kzalloc(sizeof(*m), GFP_KERNEL); |
1da177e4 | 194 | if (m) { |
1da177e4 | 195 | INIT_LIST_HEAD(&m->priority_groups); |
f40c67f0 | 196 | INIT_LIST_HEAD(&m->queued_ios); |
1da177e4 LT |
197 | spin_lock_init(&m->lock); |
198 | m->queue_io = 1; | |
4e2d19e4 | 199 | m->pg_init_delay_msecs = DM_PG_INIT_DELAY_DEFAULT; |
c4028958 DH |
200 | INIT_WORK(&m->process_queued_ios, process_queued_ios); |
201 | INIT_WORK(&m->trigger_event, trigger_event); | |
2bded7bd | 202 | init_waitqueue_head(&m->pg_init_wait); |
6380f26f | 203 | mutex_init(&m->work_mutex); |
93d2341c | 204 | m->mpio_pool = mempool_create_slab_pool(MIN_IOS, _mpio_cache); |
1da177e4 LT |
205 | if (!m->mpio_pool) { |
206 | kfree(m); | |
207 | return NULL; | |
208 | } | |
28f16c20 MM |
209 | m->ti = ti; |
210 | ti->private = m; | |
1da177e4 LT |
211 | } |
212 | ||
213 | return m; | |
214 | } | |
215 | ||
216 | static void free_multipath(struct multipath *m) | |
217 | { | |
218 | struct priority_group *pg, *tmp; | |
1da177e4 LT |
219 | |
220 | list_for_each_entry_safe(pg, tmp, &m->priority_groups, list) { | |
221 | list_del(&pg->list); | |
222 | free_priority_group(pg, m->ti); | |
223 | } | |
224 | ||
cfae5c9b | 225 | kfree(m->hw_handler_name); |
2bfd2e13 | 226 | kfree(m->hw_handler_params); |
1da177e4 LT |
227 | mempool_destroy(m->mpio_pool); |
228 | kfree(m); | |
229 | } | |
230 | ||
466891f9 JN |
231 | static int set_mapinfo(struct multipath *m, union map_info *info) |
232 | { | |
233 | struct dm_mpath_io *mpio; | |
234 | ||
235 | mpio = mempool_alloc(m->mpio_pool, GFP_ATOMIC); | |
236 | if (!mpio) | |
237 | return -ENOMEM; | |
238 | ||
239 | memset(mpio, 0, sizeof(*mpio)); | |
240 | info->ptr = mpio; | |
241 | ||
242 | return 0; | |
243 | } | |
244 | ||
245 | static void clear_mapinfo(struct multipath *m, union map_info *info) | |
246 | { | |
247 | struct dm_mpath_io *mpio = info->ptr; | |
248 | ||
249 | info->ptr = NULL; | |
250 | mempool_free(mpio, m->mpio_pool); | |
251 | } | |
1da177e4 LT |
252 | |
253 | /*----------------------------------------------- | |
254 | * Path selection | |
255 | *-----------------------------------------------*/ | |
256 | ||
fb612642 KU |
257 | static void __pg_init_all_paths(struct multipath *m) |
258 | { | |
259 | struct pgpath *pgpath; | |
4e2d19e4 | 260 | unsigned long pg_init_delay = 0; |
fb612642 KU |
261 | |
262 | m->pg_init_count++; | |
263 | m->pg_init_required = 0; | |
4e2d19e4 CS |
264 | if (m->pg_init_delay_retry) |
265 | pg_init_delay = msecs_to_jiffies(m->pg_init_delay_msecs != DM_PG_INIT_DELAY_DEFAULT ? | |
266 | m->pg_init_delay_msecs : DM_PG_INIT_DELAY_MSECS); | |
fb612642 KU |
267 | list_for_each_entry(pgpath, &m->current_pg->pgpaths, list) { |
268 | /* Skip failed paths */ | |
269 | if (!pgpath->is_active) | |
270 | continue; | |
4e2d19e4 CS |
271 | if (queue_delayed_work(kmpath_handlerd, &pgpath->activate_path, |
272 | pg_init_delay)) | |
fb612642 KU |
273 | m->pg_init_in_progress++; |
274 | } | |
275 | } | |
276 | ||
1da177e4 LT |
277 | static void __switch_pg(struct multipath *m, struct pgpath *pgpath) |
278 | { | |
1da177e4 LT |
279 | m->current_pg = pgpath->pg; |
280 | ||
281 | /* Must we initialise the PG first, and queue I/O till it's ready? */ | |
cfae5c9b | 282 | if (m->hw_handler_name) { |
1da177e4 LT |
283 | m->pg_init_required = 1; |
284 | m->queue_io = 1; | |
285 | } else { | |
286 | m->pg_init_required = 0; | |
287 | m->queue_io = 0; | |
288 | } | |
c9e45581 DW |
289 | |
290 | m->pg_init_count = 0; | |
1da177e4 LT |
291 | } |
292 | ||
02ab823f KU |
293 | static int __choose_path_in_pg(struct multipath *m, struct priority_group *pg, |
294 | size_t nr_bytes) | |
1da177e4 | 295 | { |
c922d5f7 | 296 | struct dm_path *path; |
1da177e4 | 297 | |
02ab823f | 298 | path = pg->ps.type->select_path(&pg->ps, &m->repeat_count, nr_bytes); |
1da177e4 LT |
299 | if (!path) |
300 | return -ENXIO; | |
301 | ||
302 | m->current_pgpath = path_to_pgpath(path); | |
303 | ||
304 | if (m->current_pg != pg) | |
305 | __switch_pg(m, m->current_pgpath); | |
306 | ||
307 | return 0; | |
308 | } | |
309 | ||
02ab823f | 310 | static void __choose_pgpath(struct multipath *m, size_t nr_bytes) |
1da177e4 LT |
311 | { |
312 | struct priority_group *pg; | |
313 | unsigned bypassed = 1; | |
314 | ||
315 | if (!m->nr_valid_paths) | |
316 | goto failed; | |
317 | ||
318 | /* Were we instructed to switch PG? */ | |
319 | if (m->next_pg) { | |
320 | pg = m->next_pg; | |
321 | m->next_pg = NULL; | |
02ab823f | 322 | if (!__choose_path_in_pg(m, pg, nr_bytes)) |
1da177e4 LT |
323 | return; |
324 | } | |
325 | ||
326 | /* Don't change PG until it has no remaining paths */ | |
02ab823f | 327 | if (m->current_pg && !__choose_path_in_pg(m, m->current_pg, nr_bytes)) |
1da177e4 LT |
328 | return; |
329 | ||
330 | /* | |
331 | * Loop through priority groups until we find a valid path. | |
332 | * First time we skip PGs marked 'bypassed'. | |
f220fd4e MC |
333 | * Second time we only try the ones we skipped, but set |
334 | * pg_init_delay_retry so we do not hammer controllers. | |
1da177e4 LT |
335 | */ |
336 | do { | |
337 | list_for_each_entry(pg, &m->priority_groups, list) { | |
338 | if (pg->bypassed == bypassed) | |
339 | continue; | |
f220fd4e MC |
340 | if (!__choose_path_in_pg(m, pg, nr_bytes)) { |
341 | if (!bypassed) | |
342 | m->pg_init_delay_retry = 1; | |
1da177e4 | 343 | return; |
f220fd4e | 344 | } |
1da177e4 LT |
345 | } |
346 | } while (bypassed--); | |
347 | ||
348 | failed: | |
349 | m->current_pgpath = NULL; | |
350 | m->current_pg = NULL; | |
351 | } | |
352 | ||
45e15720 KU |
353 | /* |
354 | * Check whether bios must be queued in the device-mapper core rather | |
355 | * than here in the target. | |
356 | * | |
357 | * m->lock must be held on entry. | |
358 | * | |
359 | * If m->queue_if_no_path and m->saved_queue_if_no_path hold the | |
360 | * same value then we are not between multipath_presuspend() | |
361 | * and multipath_resume() calls and we have no need to check | |
362 | * for the DMF_NOFLUSH_SUSPENDING flag. | |
363 | */ | |
364 | static int __must_push_back(struct multipath *m) | |
365 | { | |
366 | return (m->queue_if_no_path != m->saved_queue_if_no_path && | |
367 | dm_noflush_suspending(m->ti)); | |
368 | } | |
369 | ||
f40c67f0 | 370 | static int map_io(struct multipath *m, struct request *clone, |
466891f9 | 371 | union map_info *map_context, unsigned was_queued) |
1da177e4 | 372 | { |
d2a7ad29 | 373 | int r = DM_MAPIO_REMAPPED; |
f40c67f0 | 374 | size_t nr_bytes = blk_rq_bytes(clone); |
1da177e4 LT |
375 | unsigned long flags; |
376 | struct pgpath *pgpath; | |
f40c67f0 | 377 | struct block_device *bdev; |
466891f9 | 378 | struct dm_mpath_io *mpio = map_context->ptr; |
1da177e4 LT |
379 | |
380 | spin_lock_irqsave(&m->lock, flags); | |
381 | ||
382 | /* Do we need to select a new pgpath? */ | |
383 | if (!m->current_pgpath || | |
384 | (!m->queue_io && (m->repeat_count && --m->repeat_count == 0))) | |
02ab823f | 385 | __choose_pgpath(m, nr_bytes); |
1da177e4 LT |
386 | |
387 | pgpath = m->current_pgpath; | |
388 | ||
389 | if (was_queued) | |
390 | m->queue_size--; | |
391 | ||
392 | if ((pgpath && m->queue_io) || | |
436d4108 | 393 | (!pgpath && m->queue_if_no_path)) { |
1da177e4 | 394 | /* Queue for the daemon to resubmit */ |
f40c67f0 | 395 | list_add_tail(&clone->queuelist, &m->queued_ios); |
1da177e4 | 396 | m->queue_size++; |
c3cd4f6b AK |
397 | if ((m->pg_init_required && !m->pg_init_in_progress) || |
398 | !m->queue_io) | |
c557308e | 399 | queue_work(kmultipathd, &m->process_queued_ios); |
1da177e4 | 400 | pgpath = NULL; |
d2a7ad29 | 401 | r = DM_MAPIO_SUBMITTED; |
f40c67f0 KU |
402 | } else if (pgpath) { |
403 | bdev = pgpath->path.dev->bdev; | |
404 | clone->q = bdev_get_queue(bdev); | |
405 | clone->rq_disk = bdev->bd_disk; | |
406 | } else if (__must_push_back(m)) | |
45e15720 KU |
407 | r = DM_MAPIO_REQUEUE; |
408 | else | |
409 | r = -EIO; /* Failed */ | |
1da177e4 LT |
410 | |
411 | mpio->pgpath = pgpath; | |
02ab823f KU |
412 | mpio->nr_bytes = nr_bytes; |
413 | ||
414 | if (r == DM_MAPIO_REMAPPED && pgpath->pg->ps.type->start_io) | |
415 | pgpath->pg->ps.type->start_io(&pgpath->pg->ps, &pgpath->path, | |
416 | nr_bytes); | |
1da177e4 LT |
417 | |
418 | spin_unlock_irqrestore(&m->lock, flags); | |
419 | ||
420 | return r; | |
421 | } | |
422 | ||
423 | /* | |
424 | * If we run out of usable paths, should we queue I/O or error it? | |
425 | */ | |
485ef69e AK |
426 | static int queue_if_no_path(struct multipath *m, unsigned queue_if_no_path, |
427 | unsigned save_old_value) | |
1da177e4 LT |
428 | { |
429 | unsigned long flags; | |
430 | ||
431 | spin_lock_irqsave(&m->lock, flags); | |
432 | ||
485ef69e AK |
433 | if (save_old_value) |
434 | m->saved_queue_if_no_path = m->queue_if_no_path; | |
435 | else | |
436 | m->saved_queue_if_no_path = queue_if_no_path; | |
1da177e4 | 437 | m->queue_if_no_path = queue_if_no_path; |
c3cd4f6b | 438 | if (!m->queue_if_no_path && m->queue_size) |
c557308e | 439 | queue_work(kmultipathd, &m->process_queued_ios); |
1da177e4 LT |
440 | |
441 | spin_unlock_irqrestore(&m->lock, flags); | |
442 | ||
443 | return 0; | |
444 | } | |
445 | ||
446 | /*----------------------------------------------------------------- | |
447 | * The multipath daemon is responsible for resubmitting queued ios. | |
448 | *---------------------------------------------------------------*/ | |
449 | ||
450 | static void dispatch_queued_ios(struct multipath *m) | |
451 | { | |
452 | int r; | |
453 | unsigned long flags; | |
1da177e4 | 454 | union map_info *info; |
f40c67f0 KU |
455 | struct request *clone, *n; |
456 | LIST_HEAD(cl); | |
1da177e4 LT |
457 | |
458 | spin_lock_irqsave(&m->lock, flags); | |
f40c67f0 | 459 | list_splice_init(&m->queued_ios, &cl); |
1da177e4 LT |
460 | spin_unlock_irqrestore(&m->lock, flags); |
461 | ||
f40c67f0 KU |
462 | list_for_each_entry_safe(clone, n, &cl, queuelist) { |
463 | list_del_init(&clone->queuelist); | |
1da177e4 | 464 | |
f40c67f0 | 465 | info = dm_get_rq_mapinfo(clone); |
1da177e4 | 466 | |
466891f9 | 467 | r = map_io(m, clone, info, 1); |
f40c67f0 | 468 | if (r < 0) { |
466891f9 | 469 | clear_mapinfo(m, info); |
f40c67f0 KU |
470 | dm_kill_unmapped_request(clone, r); |
471 | } else if (r == DM_MAPIO_REMAPPED) | |
472 | dm_dispatch_request(clone); | |
473 | else if (r == DM_MAPIO_REQUEUE) { | |
466891f9 | 474 | clear_mapinfo(m, info); |
f40c67f0 KU |
475 | dm_requeue_unmapped_request(clone); |
476 | } | |
1da177e4 LT |
477 | } |
478 | } | |
479 | ||
c4028958 | 480 | static void process_queued_ios(struct work_struct *work) |
1da177e4 | 481 | { |
c4028958 DH |
482 | struct multipath *m = |
483 | container_of(work, struct multipath, process_queued_ios); | |
fb612642 | 484 | struct pgpath *pgpath = NULL; |
e54f77dd | 485 | unsigned must_queue = 1; |
1da177e4 LT |
486 | unsigned long flags; |
487 | ||
488 | spin_lock_irqsave(&m->lock, flags); | |
489 | ||
490 | if (!m->current_pgpath) | |
02ab823f | 491 | __choose_pgpath(m, 0); |
1da177e4 LT |
492 | |
493 | pgpath = m->current_pgpath; | |
494 | ||
c3cd4f6b AK |
495 | if ((pgpath && !m->queue_io) || |
496 | (!pgpath && !m->queue_if_no_path)) | |
497 | must_queue = 0; | |
1da177e4 | 498 | |
fb612642 KU |
499 | if (m->pg_init_required && !m->pg_init_in_progress && pgpath) |
500 | __pg_init_all_paths(m); | |
501 | ||
1da177e4 | 502 | spin_unlock_irqrestore(&m->lock, flags); |
1da177e4 LT |
503 | if (!must_queue) |
504 | dispatch_queued_ios(m); | |
505 | } | |
506 | ||
507 | /* | |
508 | * An event is triggered whenever a path is taken out of use. | |
509 | * Includes path failure and PG bypass. | |
510 | */ | |
c4028958 | 511 | static void trigger_event(struct work_struct *work) |
1da177e4 | 512 | { |
c4028958 DH |
513 | struct multipath *m = |
514 | container_of(work, struct multipath, trigger_event); | |
1da177e4 LT |
515 | |
516 | dm_table_event(m->ti->table); | |
517 | } | |
518 | ||
519 | /*----------------------------------------------------------------- | |
520 | * Constructor/argument parsing: | |
521 | * <#multipath feature args> [<arg>]* | |
522 | * <#hw_handler args> [hw_handler [<arg>]*] | |
523 | * <#priority groups> | |
524 | * <initial priority group> | |
525 | * [<selector> <#selector args> [<arg>]* | |
526 | * <#paths> <#per-path selector args> | |
527 | * [<path> [<arg>]* ]+ ]+ | |
528 | *---------------------------------------------------------------*/ | |
498f0103 | 529 | static int parse_path_selector(struct dm_arg_set *as, struct priority_group *pg, |
1da177e4 LT |
530 | struct dm_target *ti) |
531 | { | |
532 | int r; | |
533 | struct path_selector_type *pst; | |
534 | unsigned ps_argc; | |
535 | ||
498f0103 | 536 | static struct dm_arg _args[] = { |
72d94861 | 537 | {0, 1024, "invalid number of path selector args"}, |
1da177e4 LT |
538 | }; |
539 | ||
498f0103 | 540 | pst = dm_get_path_selector(dm_shift_arg(as)); |
1da177e4 | 541 | if (!pst) { |
72d94861 | 542 | ti->error = "unknown path selector type"; |
1da177e4 LT |
543 | return -EINVAL; |
544 | } | |
545 | ||
498f0103 | 546 | r = dm_read_arg_group(_args, as, &ps_argc, &ti->error); |
371b2e34 MP |
547 | if (r) { |
548 | dm_put_path_selector(pst); | |
1da177e4 | 549 | return -EINVAL; |
371b2e34 | 550 | } |
1da177e4 LT |
551 | |
552 | r = pst->create(&pg->ps, ps_argc, as->argv); | |
553 | if (r) { | |
554 | dm_put_path_selector(pst); | |
72d94861 | 555 | ti->error = "path selector constructor failed"; |
1da177e4 LT |
556 | return r; |
557 | } | |
558 | ||
559 | pg->ps.type = pst; | |
498f0103 | 560 | dm_consume_args(as, ps_argc); |
1da177e4 LT |
561 | |
562 | return 0; | |
563 | } | |
564 | ||
498f0103 | 565 | static struct pgpath *parse_path(struct dm_arg_set *as, struct path_selector *ps, |
1da177e4 LT |
566 | struct dm_target *ti) |
567 | { | |
568 | int r; | |
569 | struct pgpath *p; | |
ae11b1b3 | 570 | struct multipath *m = ti->private; |
1da177e4 LT |
571 | |
572 | /* we need at least a path arg */ | |
573 | if (as->argc < 1) { | |
72d94861 | 574 | ti->error = "no device given"; |
01460f35 | 575 | return ERR_PTR(-EINVAL); |
1da177e4 LT |
576 | } |
577 | ||
578 | p = alloc_pgpath(); | |
579 | if (!p) | |
01460f35 | 580 | return ERR_PTR(-ENOMEM); |
1da177e4 | 581 | |
498f0103 | 582 | r = dm_get_device(ti, dm_shift_arg(as), dm_table_get_mode(ti->table), |
8215d6ec | 583 | &p->path.dev); |
1da177e4 | 584 | if (r) { |
72d94861 | 585 | ti->error = "error getting device"; |
1da177e4 LT |
586 | goto bad; |
587 | } | |
588 | ||
ae11b1b3 | 589 | if (m->hw_handler_name) { |
a0cf7ea9 HR |
590 | struct request_queue *q = bdev_get_queue(p->path.dev->bdev); |
591 | ||
592 | r = scsi_dh_attach(q, m->hw_handler_name); | |
593 | if (r == -EBUSY) { | |
594 | /* | |
595 | * Already attached to different hw_handler, | |
596 | * try to reattach with correct one. | |
597 | */ | |
598 | scsi_dh_detach(q); | |
599 | r = scsi_dh_attach(q, m->hw_handler_name); | |
600 | } | |
601 | ||
ae11b1b3 | 602 | if (r < 0) { |
a0cf7ea9 | 603 | ti->error = "error attaching hardware handler"; |
ae11b1b3 HR |
604 | dm_put_device(ti, p->path.dev); |
605 | goto bad; | |
606 | } | |
2bfd2e13 CS |
607 | |
608 | if (m->hw_handler_params) { | |
609 | r = scsi_dh_set_params(q, m->hw_handler_params); | |
610 | if (r < 0) { | |
611 | ti->error = "unable to set hardware " | |
612 | "handler parameters"; | |
613 | scsi_dh_detach(q); | |
614 | dm_put_device(ti, p->path.dev); | |
615 | goto bad; | |
616 | } | |
617 | } | |
ae11b1b3 HR |
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 | ||
498f0103 | 633 | static struct priority_group *parse_priority_group(struct dm_arg_set *as, |
28f16c20 | 634 | struct multipath *m) |
1da177e4 | 635 | { |
498f0103 | 636 | static struct dm_arg _args[] = { |
72d94861 AK |
637 | {1, 1024, "invalid number of paths"}, |
638 | {0, 1024, "invalid number of selector args"} | |
1da177e4 LT |
639 | }; |
640 | ||
641 | int r; | |
498f0103 | 642 | unsigned i, nr_selector_args, nr_args; |
1da177e4 | 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 | */ | |
498f0103 | 666 | r = dm_read_arg(_args, as, &pg->nr_pgpaths, &ti->error); |
1da177e4 LT |
667 | if (r) |
668 | goto bad; | |
669 | ||
498f0103 | 670 | r = dm_read_arg(_args + 1, as, &nr_selector_args, &ti->error); |
1da177e4 LT |
671 | if (r) |
672 | goto bad; | |
673 | ||
498f0103 | 674 | nr_args = 1 + nr_selector_args; |
1da177e4 LT |
675 | for (i = 0; i < pg->nr_pgpaths; i++) { |
676 | struct pgpath *pgpath; | |
498f0103 | 677 | struct dm_arg_set path_args; |
1da177e4 | 678 | |
498f0103 | 679 | if (as->argc < nr_args) { |
148acff6 | 680 | ti->error = "not enough path parameters"; |
6bbf79a1 | 681 | r = -EINVAL; |
1da177e4 | 682 | goto bad; |
148acff6 | 683 | } |
1da177e4 | 684 | |
498f0103 | 685 | path_args.argc = nr_args; |
1da177e4 LT |
686 | path_args.argv = as->argv; |
687 | ||
688 | pgpath = parse_path(&path_args, &pg->ps, ti); | |
01460f35 BM |
689 | if (IS_ERR(pgpath)) { |
690 | r = PTR_ERR(pgpath); | |
1da177e4 | 691 | goto bad; |
01460f35 | 692 | } |
1da177e4 LT |
693 | |
694 | pgpath->pg = pg; | |
695 | list_add_tail(&pgpath->list, &pg->pgpaths); | |
498f0103 | 696 | dm_consume_args(as, nr_args); |
1da177e4 LT |
697 | } |
698 | ||
699 | return pg; | |
700 | ||
701 | bad: | |
702 | free_priority_group(pg, ti); | |
01460f35 | 703 | return ERR_PTR(r); |
1da177e4 LT |
704 | } |
705 | ||
498f0103 | 706 | static int parse_hw_handler(struct dm_arg_set *as, struct multipath *m) |
1da177e4 | 707 | { |
1da177e4 | 708 | unsigned hw_argc; |
2bfd2e13 | 709 | int ret; |
28f16c20 | 710 | struct dm_target *ti = m->ti; |
1da177e4 | 711 | |
498f0103 | 712 | static struct dm_arg _args[] = { |
72d94861 | 713 | {0, 1024, "invalid number of hardware handler args"}, |
1da177e4 LT |
714 | }; |
715 | ||
498f0103 | 716 | if (dm_read_arg_group(_args, as, &hw_argc, &ti->error)) |
1da177e4 LT |
717 | return -EINVAL; |
718 | ||
719 | if (!hw_argc) | |
720 | return 0; | |
721 | ||
498f0103 | 722 | m->hw_handler_name = kstrdup(dm_shift_arg(as), GFP_KERNEL); |
510193a2 MS |
723 | if (!try_then_request_module(scsi_dh_handler_exist(m->hw_handler_name), |
724 | "scsi_dh_%s", m->hw_handler_name)) { | |
72d94861 | 725 | ti->error = "unknown hardware handler type"; |
2bfd2e13 CS |
726 | ret = -EINVAL; |
727 | goto fail; | |
1da177e4 | 728 | } |
14e98c5c | 729 | |
2bfd2e13 CS |
730 | if (hw_argc > 1) { |
731 | char *p; | |
732 | int i, j, len = 4; | |
733 | ||
734 | for (i = 0; i <= hw_argc - 2; i++) | |
735 | len += strlen(as->argv[i]) + 1; | |
736 | p = m->hw_handler_params = kzalloc(len, GFP_KERNEL); | |
737 | if (!p) { | |
738 | ti->error = "memory allocation failed"; | |
739 | ret = -ENOMEM; | |
740 | goto fail; | |
741 | } | |
742 | j = sprintf(p, "%d", hw_argc - 1); | |
743 | for (i = 0, p+=j+1; i <= hw_argc - 2; i++, p+=j+1) | |
744 | j = sprintf(p, "%s", as->argv[i]); | |
745 | } | |
498f0103 | 746 | dm_consume_args(as, hw_argc - 1); |
1da177e4 LT |
747 | |
748 | return 0; | |
2bfd2e13 CS |
749 | fail: |
750 | kfree(m->hw_handler_name); | |
751 | m->hw_handler_name = NULL; | |
752 | return ret; | |
1da177e4 LT |
753 | } |
754 | ||
498f0103 | 755 | static int parse_features(struct dm_arg_set *as, struct multipath *m) |
1da177e4 LT |
756 | { |
757 | int r; | |
758 | unsigned argc; | |
28f16c20 | 759 | struct dm_target *ti = m->ti; |
498f0103 | 760 | const char *arg_name; |
1da177e4 | 761 | |
498f0103 | 762 | static struct dm_arg _args[] = { |
4e2d19e4 | 763 | {0, 5, "invalid number of feature args"}, |
c9e45581 | 764 | {1, 50, "pg_init_retries must be between 1 and 50"}, |
4e2d19e4 | 765 | {0, 60000, "pg_init_delay_msecs must be between 0 and 60000"}, |
1da177e4 LT |
766 | }; |
767 | ||
498f0103 | 768 | r = dm_read_arg_group(_args, as, &argc, &ti->error); |
1da177e4 LT |
769 | if (r) |
770 | return -EINVAL; | |
771 | ||
772 | if (!argc) | |
773 | return 0; | |
774 | ||
c9e45581 | 775 | do { |
498f0103 | 776 | arg_name = dm_shift_arg(as); |
c9e45581 DW |
777 | argc--; |
778 | ||
498f0103 | 779 | if (!strcasecmp(arg_name, "queue_if_no_path")) { |
c9e45581 DW |
780 | r = queue_if_no_path(m, 1, 0); |
781 | continue; | |
782 | } | |
783 | ||
498f0103 | 784 | if (!strcasecmp(arg_name, "pg_init_retries") && |
c9e45581 | 785 | (argc >= 1)) { |
498f0103 | 786 | r = dm_read_arg(_args + 1, as, &m->pg_init_retries, &ti->error); |
c9e45581 DW |
787 | argc--; |
788 | continue; | |
789 | } | |
790 | ||
498f0103 | 791 | if (!strcasecmp(arg_name, "pg_init_delay_msecs") && |
4e2d19e4 | 792 | (argc >= 1)) { |
498f0103 | 793 | r = dm_read_arg(_args + 2, as, &m->pg_init_delay_msecs, &ti->error); |
4e2d19e4 CS |
794 | argc--; |
795 | continue; | |
796 | } | |
797 | ||
1da177e4 | 798 | ti->error = "Unrecognised multipath feature request"; |
c9e45581 DW |
799 | r = -EINVAL; |
800 | } while (argc && !r); | |
801 | ||
802 | return r; | |
1da177e4 LT |
803 | } |
804 | ||
805 | static int multipath_ctr(struct dm_target *ti, unsigned int argc, | |
806 | char **argv) | |
807 | { | |
498f0103 MS |
808 | /* target arguments */ |
809 | static struct dm_arg _args[] = { | |
a490a07a MS |
810 | {0, 1024, "invalid number of priority groups"}, |
811 | {0, 1024, "invalid initial priority group number"}, | |
1da177e4 LT |
812 | }; |
813 | ||
814 | int r; | |
815 | struct multipath *m; | |
498f0103 | 816 | struct dm_arg_set as; |
1da177e4 LT |
817 | unsigned pg_count = 0; |
818 | unsigned next_pg_num; | |
819 | ||
820 | as.argc = argc; | |
821 | as.argv = argv; | |
822 | ||
28f16c20 | 823 | m = alloc_multipath(ti); |
1da177e4 | 824 | if (!m) { |
72d94861 | 825 | ti->error = "can't allocate multipath"; |
1da177e4 LT |
826 | return -EINVAL; |
827 | } | |
828 | ||
28f16c20 | 829 | r = parse_features(&as, m); |
1da177e4 LT |
830 | if (r) |
831 | goto bad; | |
832 | ||
28f16c20 | 833 | r = parse_hw_handler(&as, m); |
1da177e4 LT |
834 | if (r) |
835 | goto bad; | |
836 | ||
498f0103 | 837 | r = dm_read_arg(_args, &as, &m->nr_priority_groups, &ti->error); |
1da177e4 LT |
838 | if (r) |
839 | goto bad; | |
840 | ||
498f0103 | 841 | r = dm_read_arg(_args + 1, &as, &next_pg_num, &ti->error); |
1da177e4 LT |
842 | if (r) |
843 | goto bad; | |
844 | ||
a490a07a MS |
845 | if ((!m->nr_priority_groups && next_pg_num) || |
846 | (m->nr_priority_groups && !next_pg_num)) { | |
847 | ti->error = "invalid initial priority group"; | |
848 | r = -EINVAL; | |
849 | goto bad; | |
850 | } | |
851 | ||
1da177e4 LT |
852 | /* parse the priority groups */ |
853 | while (as.argc) { | |
854 | struct priority_group *pg; | |
855 | ||
28f16c20 | 856 | pg = parse_priority_group(&as, m); |
01460f35 BM |
857 | if (IS_ERR(pg)) { |
858 | r = PTR_ERR(pg); | |
1da177e4 LT |
859 | goto bad; |
860 | } | |
861 | ||
862 | m->nr_valid_paths += pg->nr_pgpaths; | |
863 | list_add_tail(&pg->list, &m->priority_groups); | |
864 | pg_count++; | |
865 | pg->pg_num = pg_count; | |
866 | if (!--next_pg_num) | |
867 | m->next_pg = pg; | |
868 | } | |
869 | ||
870 | if (pg_count != m->nr_priority_groups) { | |
72d94861 | 871 | ti->error = "priority group count mismatch"; |
1da177e4 LT |
872 | r = -EINVAL; |
873 | goto bad; | |
874 | } | |
875 | ||
8627921f | 876 | ti->num_flush_requests = 1; |
959eb4e5 | 877 | ti->num_discard_requests = 1; |
8627921f | 878 | |
1da177e4 LT |
879 | return 0; |
880 | ||
881 | bad: | |
882 | free_multipath(m); | |
883 | return r; | |
884 | } | |
885 | ||
2bded7bd KU |
886 | static void multipath_wait_for_pg_init_completion(struct multipath *m) |
887 | { | |
888 | DECLARE_WAITQUEUE(wait, current); | |
889 | unsigned long flags; | |
890 | ||
891 | add_wait_queue(&m->pg_init_wait, &wait); | |
892 | ||
893 | while (1) { | |
894 | set_current_state(TASK_UNINTERRUPTIBLE); | |
895 | ||
896 | spin_lock_irqsave(&m->lock, flags); | |
897 | if (!m->pg_init_in_progress) { | |
898 | spin_unlock_irqrestore(&m->lock, flags); | |
899 | break; | |
900 | } | |
901 | spin_unlock_irqrestore(&m->lock, flags); | |
902 | ||
903 | io_schedule(); | |
904 | } | |
905 | set_current_state(TASK_RUNNING); | |
906 | ||
907 | remove_wait_queue(&m->pg_init_wait, &wait); | |
908 | } | |
909 | ||
910 | static void flush_multipath_work(struct multipath *m) | |
1da177e4 | 911 | { |
bab7cfc7 | 912 | flush_workqueue(kmpath_handlerd); |
2bded7bd | 913 | multipath_wait_for_pg_init_completion(m); |
a044d016 | 914 | flush_workqueue(kmultipathd); |
d5ffa387 | 915 | flush_work_sync(&m->trigger_event); |
6df400ab KU |
916 | } |
917 | ||
918 | static void multipath_dtr(struct dm_target *ti) | |
919 | { | |
920 | struct multipath *m = ti->private; | |
921 | ||
2bded7bd | 922 | flush_multipath_work(m); |
1da177e4 LT |
923 | free_multipath(m); |
924 | } | |
925 | ||
926 | /* | |
f40c67f0 | 927 | * Map cloned requests |
1da177e4 | 928 | */ |
f40c67f0 | 929 | static int multipath_map(struct dm_target *ti, struct request *clone, |
1da177e4 LT |
930 | union map_info *map_context) |
931 | { | |
932 | int r; | |
1da177e4 LT |
933 | struct multipath *m = (struct multipath *) ti->private; |
934 | ||
466891f9 | 935 | if (set_mapinfo(m, map_context) < 0) |
f40c67f0 KU |
936 | /* ENOMEM, requeue */ |
937 | return DM_MAPIO_REQUEUE; | |
1da177e4 | 938 | |
f40c67f0 | 939 | clone->cmd_flags |= REQ_FAILFAST_TRANSPORT; |
466891f9 | 940 | r = map_io(m, clone, map_context, 0); |
45e15720 | 941 | if (r < 0 || r == DM_MAPIO_REQUEUE) |
466891f9 | 942 | clear_mapinfo(m, map_context); |
1da177e4 LT |
943 | |
944 | return r; | |
945 | } | |
946 | ||
947 | /* | |
948 | * Take a path out of use. | |
949 | */ | |
950 | static int fail_path(struct pgpath *pgpath) | |
951 | { | |
952 | unsigned long flags; | |
953 | struct multipath *m = pgpath->pg->m; | |
954 | ||
955 | spin_lock_irqsave(&m->lock, flags); | |
956 | ||
6680073d | 957 | if (!pgpath->is_active) |
1da177e4 LT |
958 | goto out; |
959 | ||
72d94861 | 960 | DMWARN("Failing path %s.", pgpath->path.dev->name); |
1da177e4 LT |
961 | |
962 | pgpath->pg->ps.type->fail_path(&pgpath->pg->ps, &pgpath->path); | |
6680073d | 963 | pgpath->is_active = 0; |
1da177e4 LT |
964 | pgpath->fail_count++; |
965 | ||
966 | m->nr_valid_paths--; | |
967 | ||
968 | if (pgpath == m->current_pgpath) | |
969 | m->current_pgpath = NULL; | |
970 | ||
b15546f9 MA |
971 | dm_path_uevent(DM_UEVENT_PATH_FAILED, m->ti, |
972 | pgpath->path.dev->name, m->nr_valid_paths); | |
973 | ||
fe9cf30e | 974 | schedule_work(&m->trigger_event); |
1da177e4 LT |
975 | |
976 | out: | |
977 | spin_unlock_irqrestore(&m->lock, flags); | |
978 | ||
979 | return 0; | |
980 | } | |
981 | ||
982 | /* | |
983 | * Reinstate a previously-failed path | |
984 | */ | |
985 | static int reinstate_path(struct pgpath *pgpath) | |
986 | { | |
987 | int r = 0; | |
988 | unsigned long flags; | |
989 | struct multipath *m = pgpath->pg->m; | |
990 | ||
991 | spin_lock_irqsave(&m->lock, flags); | |
992 | ||
6680073d | 993 | if (pgpath->is_active) |
1da177e4 LT |
994 | goto out; |
995 | ||
def052d2 | 996 | if (!pgpath->pg->ps.type->reinstate_path) { |
1da177e4 LT |
997 | DMWARN("Reinstate path not supported by path selector %s", |
998 | pgpath->pg->ps.type->name); | |
999 | r = -EINVAL; | |
1000 | goto out; | |
1001 | } | |
1002 | ||
1003 | r = pgpath->pg->ps.type->reinstate_path(&pgpath->pg->ps, &pgpath->path); | |
1004 | if (r) | |
1005 | goto out; | |
1006 | ||
6680073d | 1007 | pgpath->is_active = 1; |
1da177e4 | 1008 | |
e54f77dd CS |
1009 | if (!m->nr_valid_paths++ && m->queue_size) { |
1010 | m->current_pgpath = NULL; | |
c557308e | 1011 | queue_work(kmultipathd, &m->process_queued_ios); |
e54f77dd | 1012 | } else if (m->hw_handler_name && (m->current_pg == pgpath->pg)) { |
4e2d19e4 | 1013 | if (queue_work(kmpath_handlerd, &pgpath->activate_path.work)) |
e54f77dd CS |
1014 | m->pg_init_in_progress++; |
1015 | } | |
1da177e4 | 1016 | |
b15546f9 MA |
1017 | dm_path_uevent(DM_UEVENT_PATH_REINSTATED, m->ti, |
1018 | pgpath->path.dev->name, m->nr_valid_paths); | |
1019 | ||
fe9cf30e | 1020 | schedule_work(&m->trigger_event); |
1da177e4 LT |
1021 | |
1022 | out: | |
1023 | spin_unlock_irqrestore(&m->lock, flags); | |
1024 | ||
1025 | return r; | |
1026 | } | |
1027 | ||
1028 | /* | |
1029 | * Fail or reinstate all paths that match the provided struct dm_dev. | |
1030 | */ | |
1031 | static int action_dev(struct multipath *m, struct dm_dev *dev, | |
1032 | action_fn action) | |
1033 | { | |
19040c0b | 1034 | int r = -EINVAL; |
1da177e4 LT |
1035 | struct pgpath *pgpath; |
1036 | struct priority_group *pg; | |
1037 | ||
1038 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1039 | list_for_each_entry(pgpath, &pg->pgpaths, list) { | |
1040 | if (pgpath->path.dev == dev) | |
1041 | r = action(pgpath); | |
1042 | } | |
1043 | } | |
1044 | ||
1045 | return r; | |
1046 | } | |
1047 | ||
1048 | /* | |
1049 | * Temporarily try to avoid having to use the specified PG | |
1050 | */ | |
1051 | static void bypass_pg(struct multipath *m, struct priority_group *pg, | |
1052 | int bypassed) | |
1053 | { | |
1054 | unsigned long flags; | |
1055 | ||
1056 | spin_lock_irqsave(&m->lock, flags); | |
1057 | ||
1058 | pg->bypassed = bypassed; | |
1059 | m->current_pgpath = NULL; | |
1060 | m->current_pg = NULL; | |
1061 | ||
1062 | spin_unlock_irqrestore(&m->lock, flags); | |
1063 | ||
fe9cf30e | 1064 | schedule_work(&m->trigger_event); |
1da177e4 LT |
1065 | } |
1066 | ||
1067 | /* | |
1068 | * Switch to using the specified PG from the next I/O that gets mapped | |
1069 | */ | |
1070 | static int switch_pg_num(struct multipath *m, const char *pgstr) | |
1071 | { | |
1072 | struct priority_group *pg; | |
1073 | unsigned pgnum; | |
1074 | unsigned long flags; | |
31998ef1 | 1075 | char dummy; |
1da177e4 | 1076 | |
31998ef1 | 1077 | if (!pgstr || (sscanf(pgstr, "%u%c", &pgnum, &dummy) != 1) || !pgnum || |
1da177e4 LT |
1078 | (pgnum > m->nr_priority_groups)) { |
1079 | DMWARN("invalid PG number supplied to switch_pg_num"); | |
1080 | return -EINVAL; | |
1081 | } | |
1082 | ||
1083 | spin_lock_irqsave(&m->lock, flags); | |
1084 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1085 | pg->bypassed = 0; | |
1086 | if (--pgnum) | |
1087 | continue; | |
1088 | ||
1089 | m->current_pgpath = NULL; | |
1090 | m->current_pg = NULL; | |
1091 | m->next_pg = pg; | |
1092 | } | |
1093 | spin_unlock_irqrestore(&m->lock, flags); | |
1094 | ||
fe9cf30e | 1095 | schedule_work(&m->trigger_event); |
1da177e4 LT |
1096 | return 0; |
1097 | } | |
1098 | ||
1099 | /* | |
1100 | * Set/clear bypassed status of a PG. | |
1101 | * PGs are numbered upwards from 1 in the order they were declared. | |
1102 | */ | |
1103 | static int bypass_pg_num(struct multipath *m, const char *pgstr, int bypassed) | |
1104 | { | |
1105 | struct priority_group *pg; | |
1106 | unsigned pgnum; | |
31998ef1 | 1107 | char dummy; |
1da177e4 | 1108 | |
31998ef1 | 1109 | if (!pgstr || (sscanf(pgstr, "%u%c", &pgnum, &dummy) != 1) || !pgnum || |
1da177e4 LT |
1110 | (pgnum > m->nr_priority_groups)) { |
1111 | DMWARN("invalid PG number supplied to bypass_pg"); | |
1112 | return -EINVAL; | |
1113 | } | |
1114 | ||
1115 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1116 | if (!--pgnum) | |
1117 | break; | |
1118 | } | |
1119 | ||
1120 | bypass_pg(m, pg, bypassed); | |
1121 | return 0; | |
1122 | } | |
1123 | ||
c9e45581 DW |
1124 | /* |
1125 | * Should we retry pg_init immediately? | |
1126 | */ | |
1127 | static int pg_init_limit_reached(struct multipath *m, struct pgpath *pgpath) | |
1128 | { | |
1129 | unsigned long flags; | |
1130 | int limit_reached = 0; | |
1131 | ||
1132 | spin_lock_irqsave(&m->lock, flags); | |
1133 | ||
1134 | if (m->pg_init_count <= m->pg_init_retries) | |
1135 | m->pg_init_required = 1; | |
1136 | else | |
1137 | limit_reached = 1; | |
1138 | ||
1139 | spin_unlock_irqrestore(&m->lock, flags); | |
1140 | ||
1141 | return limit_reached; | |
1142 | } | |
1143 | ||
3ae31f6a | 1144 | static void pg_init_done(void *data, int errors) |
cfae5c9b | 1145 | { |
83c0d5d5 | 1146 | struct pgpath *pgpath = data; |
cfae5c9b CS |
1147 | struct priority_group *pg = pgpath->pg; |
1148 | struct multipath *m = pg->m; | |
1149 | unsigned long flags; | |
4e2d19e4 | 1150 | unsigned delay_retry = 0; |
cfae5c9b CS |
1151 | |
1152 | /* device or driver problems */ | |
1153 | switch (errors) { | |
1154 | case SCSI_DH_OK: | |
1155 | break; | |
1156 | case SCSI_DH_NOSYS: | |
1157 | if (!m->hw_handler_name) { | |
1158 | errors = 0; | |
1159 | break; | |
1160 | } | |
f7b934c8 MB |
1161 | DMERR("Could not failover the device: Handler scsi_dh_%s " |
1162 | "Error %d.", m->hw_handler_name, errors); | |
cfae5c9b CS |
1163 | /* |
1164 | * Fail path for now, so we do not ping pong | |
1165 | */ | |
1166 | fail_path(pgpath); | |
1167 | break; | |
1168 | case SCSI_DH_DEV_TEMP_BUSY: | |
1169 | /* | |
1170 | * Probably doing something like FW upgrade on the | |
1171 | * controller so try the other pg. | |
1172 | */ | |
1173 | bypass_pg(m, pg, 1); | |
1174 | break; | |
cfae5c9b | 1175 | case SCSI_DH_RETRY: |
4e2d19e4 CS |
1176 | /* Wait before retrying. */ |
1177 | delay_retry = 1; | |
cfae5c9b CS |
1178 | case SCSI_DH_IMM_RETRY: |
1179 | case SCSI_DH_RES_TEMP_UNAVAIL: | |
1180 | if (pg_init_limit_reached(m, pgpath)) | |
1181 | fail_path(pgpath); | |
1182 | errors = 0; | |
1183 | break; | |
1184 | default: | |
1185 | /* | |
1186 | * We probably do not want to fail the path for a device | |
1187 | * error, but this is what the old dm did. In future | |
1188 | * patches we can do more advanced handling. | |
1189 | */ | |
1190 | fail_path(pgpath); | |
1191 | } | |
1192 | ||
1193 | spin_lock_irqsave(&m->lock, flags); | |
1194 | if (errors) { | |
e54f77dd CS |
1195 | if (pgpath == m->current_pgpath) { |
1196 | DMERR("Could not failover device. Error %d.", errors); | |
1197 | m->current_pgpath = NULL; | |
1198 | m->current_pg = NULL; | |
1199 | } | |
d0259bf0 | 1200 | } else if (!m->pg_init_required) |
cfae5c9b | 1201 | pg->bypassed = 0; |
cfae5c9b | 1202 | |
d0259bf0 KU |
1203 | if (--m->pg_init_in_progress) |
1204 | /* Activations of other paths are still on going */ | |
1205 | goto out; | |
1206 | ||
1207 | if (!m->pg_init_required) | |
1208 | m->queue_io = 0; | |
1209 | ||
4e2d19e4 | 1210 | m->pg_init_delay_retry = delay_retry; |
d0259bf0 KU |
1211 | queue_work(kmultipathd, &m->process_queued_ios); |
1212 | ||
2bded7bd KU |
1213 | /* |
1214 | * Wake up any thread waiting to suspend. | |
1215 | */ | |
1216 | wake_up(&m->pg_init_wait); | |
1217 | ||
d0259bf0 | 1218 | out: |
cfae5c9b CS |
1219 | spin_unlock_irqrestore(&m->lock, flags); |
1220 | } | |
1221 | ||
bab7cfc7 CS |
1222 | static void activate_path(struct work_struct *work) |
1223 | { | |
e54f77dd | 1224 | struct pgpath *pgpath = |
4e2d19e4 | 1225 | container_of(work, struct pgpath, activate_path.work); |
bab7cfc7 | 1226 | |
3ae31f6a | 1227 | scsi_dh_activate(bdev_get_queue(pgpath->path.dev->bdev), |
83c0d5d5 | 1228 | pg_init_done, pgpath); |
bab7cfc7 CS |
1229 | } |
1230 | ||
1da177e4 LT |
1231 | /* |
1232 | * end_io handling | |
1233 | */ | |
f40c67f0 | 1234 | static int do_end_io(struct multipath *m, struct request *clone, |
028867ac | 1235 | int error, struct dm_mpath_io *mpio) |
1da177e4 | 1236 | { |
f40c67f0 KU |
1237 | /* |
1238 | * We don't queue any clone request inside the multipath target | |
1239 | * during end I/O handling, since those clone requests don't have | |
1240 | * bio clones. If we queue them inside the multipath target, | |
1241 | * we need to make bio clones, that requires memory allocation. | |
1242 | * (See drivers/md/dm.c:end_clone_bio() about why the clone requests | |
1243 | * don't have bio clones.) | |
1244 | * Instead of queueing the clone request here, we queue the original | |
1245 | * request into dm core, which will remake a clone request and | |
1246 | * clone bios for it and resubmit it later. | |
1247 | */ | |
1248 | int r = DM_ENDIO_REQUEUE; | |
640eb3b0 | 1249 | unsigned long flags; |
1da177e4 | 1250 | |
f40c67f0 | 1251 | if (!error && !clone->errors) |
1da177e4 LT |
1252 | return 0; /* I/O complete */ |
1253 | ||
6f13f6fb | 1254 | if (error == -EOPNOTSUPP || error == -EREMOTEIO || error == -EILSEQ) |
959eb4e5 MS |
1255 | return error; |
1256 | ||
cfae5c9b CS |
1257 | if (mpio->pgpath) |
1258 | fail_path(mpio->pgpath); | |
1da177e4 | 1259 | |
640eb3b0 | 1260 | spin_lock_irqsave(&m->lock, flags); |
751b2a7d HR |
1261 | if (!m->nr_valid_paths) { |
1262 | if (!m->queue_if_no_path) { | |
1263 | if (!__must_push_back(m)) | |
1264 | r = -EIO; | |
1265 | } else { | |
1266 | if (error == -EBADE) | |
1267 | r = error; | |
1268 | } | |
1269 | } | |
640eb3b0 | 1270 | spin_unlock_irqrestore(&m->lock, flags); |
1da177e4 | 1271 | |
f40c67f0 | 1272 | return r; |
1da177e4 LT |
1273 | } |
1274 | ||
f40c67f0 | 1275 | static int multipath_end_io(struct dm_target *ti, struct request *clone, |
1da177e4 LT |
1276 | int error, union map_info *map_context) |
1277 | { | |
028867ac AK |
1278 | struct multipath *m = ti->private; |
1279 | struct dm_mpath_io *mpio = map_context->ptr; | |
1da177e4 LT |
1280 | struct pgpath *pgpath = mpio->pgpath; |
1281 | struct path_selector *ps; | |
1282 | int r; | |
1283 | ||
466891f9 JN |
1284 | BUG_ON(!mpio); |
1285 | ||
f40c67f0 | 1286 | r = do_end_io(m, clone, error, mpio); |
1da177e4 LT |
1287 | if (pgpath) { |
1288 | ps = &pgpath->pg->ps; | |
1289 | if (ps->type->end_io) | |
02ab823f | 1290 | ps->type->end_io(ps, &pgpath->path, mpio->nr_bytes); |
1da177e4 | 1291 | } |
466891f9 | 1292 | clear_mapinfo(m, map_context); |
1da177e4 LT |
1293 | |
1294 | return r; | |
1295 | } | |
1296 | ||
1297 | /* | |
1298 | * Suspend can't complete until all the I/O is processed so if | |
436d4108 AK |
1299 | * the last path fails we must error any remaining I/O. |
1300 | * Note that if the freeze_bdev fails while suspending, the | |
1301 | * queue_if_no_path state is lost - userspace should reset it. | |
1da177e4 LT |
1302 | */ |
1303 | static void multipath_presuspend(struct dm_target *ti) | |
1304 | { | |
1305 | struct multipath *m = (struct multipath *) ti->private; | |
1da177e4 | 1306 | |
485ef69e | 1307 | queue_if_no_path(m, 0, 1); |
1da177e4 LT |
1308 | } |
1309 | ||
6df400ab KU |
1310 | static void multipath_postsuspend(struct dm_target *ti) |
1311 | { | |
6380f26f MA |
1312 | struct multipath *m = ti->private; |
1313 | ||
1314 | mutex_lock(&m->work_mutex); | |
2bded7bd | 1315 | flush_multipath_work(m); |
6380f26f | 1316 | mutex_unlock(&m->work_mutex); |
6df400ab KU |
1317 | } |
1318 | ||
436d4108 AK |
1319 | /* |
1320 | * Restore the queue_if_no_path setting. | |
1321 | */ | |
1da177e4 LT |
1322 | static void multipath_resume(struct dm_target *ti) |
1323 | { | |
1324 | struct multipath *m = (struct multipath *) ti->private; | |
1325 | unsigned long flags; | |
1326 | ||
1327 | spin_lock_irqsave(&m->lock, flags); | |
436d4108 | 1328 | m->queue_if_no_path = m->saved_queue_if_no_path; |
1da177e4 LT |
1329 | spin_unlock_irqrestore(&m->lock, flags); |
1330 | } | |
1331 | ||
1332 | /* | |
1333 | * Info output has the following format: | |
1334 | * num_multipath_feature_args [multipath_feature_args]* | |
1335 | * num_handler_status_args [handler_status_args]* | |
1336 | * num_groups init_group_number | |
1337 | * [A|D|E num_ps_status_args [ps_status_args]* | |
1338 | * num_paths num_selector_args | |
1339 | * [path_dev A|F fail_count [selector_args]* ]+ ]+ | |
1340 | * | |
1341 | * Table output has the following format (identical to the constructor string): | |
1342 | * num_feature_args [features_args]* | |
1343 | * num_handler_args hw_handler [hw_handler_args]* | |
1344 | * num_groups init_group_number | |
1345 | * [priority selector-name num_ps_args [ps_args]* | |
1346 | * num_paths num_selector_args [path_dev [selector_args]* ]+ ]+ | |
1347 | */ | |
1348 | static int multipath_status(struct dm_target *ti, status_type_t type, | |
1349 | char *result, unsigned int maxlen) | |
1350 | { | |
1351 | int sz = 0; | |
1352 | unsigned long flags; | |
1353 | struct multipath *m = (struct multipath *) ti->private; | |
1da177e4 LT |
1354 | struct priority_group *pg; |
1355 | struct pgpath *p; | |
1356 | unsigned pg_num; | |
1357 | char state; | |
1358 | ||
1359 | spin_lock_irqsave(&m->lock, flags); | |
1360 | ||
1361 | /* Features */ | |
1362 | if (type == STATUSTYPE_INFO) | |
c9e45581 DW |
1363 | DMEMIT("2 %u %u ", m->queue_size, m->pg_init_count); |
1364 | else { | |
1365 | DMEMIT("%u ", m->queue_if_no_path + | |
4e2d19e4 CS |
1366 | (m->pg_init_retries > 0) * 2 + |
1367 | (m->pg_init_delay_msecs != DM_PG_INIT_DELAY_DEFAULT) * 2); | |
c9e45581 DW |
1368 | if (m->queue_if_no_path) |
1369 | DMEMIT("queue_if_no_path "); | |
1370 | if (m->pg_init_retries) | |
1371 | DMEMIT("pg_init_retries %u ", m->pg_init_retries); | |
4e2d19e4 CS |
1372 | if (m->pg_init_delay_msecs != DM_PG_INIT_DELAY_DEFAULT) |
1373 | DMEMIT("pg_init_delay_msecs %u ", m->pg_init_delay_msecs); | |
c9e45581 | 1374 | } |
1da177e4 | 1375 | |
cfae5c9b | 1376 | if (!m->hw_handler_name || type == STATUSTYPE_INFO) |
1da177e4 LT |
1377 | DMEMIT("0 "); |
1378 | else | |
cfae5c9b | 1379 | DMEMIT("1 %s ", m->hw_handler_name); |
1da177e4 LT |
1380 | |
1381 | DMEMIT("%u ", m->nr_priority_groups); | |
1382 | ||
1383 | if (m->next_pg) | |
1384 | pg_num = m->next_pg->pg_num; | |
1385 | else if (m->current_pg) | |
1386 | pg_num = m->current_pg->pg_num; | |
1387 | else | |
a490a07a | 1388 | pg_num = (m->nr_priority_groups ? 1 : 0); |
1da177e4 LT |
1389 | |
1390 | DMEMIT("%u ", pg_num); | |
1391 | ||
1392 | switch (type) { | |
1393 | case STATUSTYPE_INFO: | |
1394 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1395 | if (pg->bypassed) | |
1396 | state = 'D'; /* Disabled */ | |
1397 | else if (pg == m->current_pg) | |
1398 | state = 'A'; /* Currently Active */ | |
1399 | else | |
1400 | state = 'E'; /* Enabled */ | |
1401 | ||
1402 | DMEMIT("%c ", state); | |
1403 | ||
1404 | if (pg->ps.type->status) | |
1405 | sz += pg->ps.type->status(&pg->ps, NULL, type, | |
1406 | result + sz, | |
1407 | maxlen - sz); | |
1408 | else | |
1409 | DMEMIT("0 "); | |
1410 | ||
1411 | DMEMIT("%u %u ", pg->nr_pgpaths, | |
1412 | pg->ps.type->info_args); | |
1413 | ||
1414 | list_for_each_entry(p, &pg->pgpaths, list) { | |
1415 | DMEMIT("%s %s %u ", p->path.dev->name, | |
6680073d | 1416 | p->is_active ? "A" : "F", |
1da177e4 LT |
1417 | p->fail_count); |
1418 | if (pg->ps.type->status) | |
1419 | sz += pg->ps.type->status(&pg->ps, | |
1420 | &p->path, type, result + sz, | |
1421 | maxlen - sz); | |
1422 | } | |
1423 | } | |
1424 | break; | |
1425 | ||
1426 | case STATUSTYPE_TABLE: | |
1427 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1428 | DMEMIT("%s ", pg->ps.type->name); | |
1429 | ||
1430 | if (pg->ps.type->status) | |
1431 | sz += pg->ps.type->status(&pg->ps, NULL, type, | |
1432 | result + sz, | |
1433 | maxlen - sz); | |
1434 | else | |
1435 | DMEMIT("0 "); | |
1436 | ||
1437 | DMEMIT("%u %u ", pg->nr_pgpaths, | |
1438 | pg->ps.type->table_args); | |
1439 | ||
1440 | list_for_each_entry(p, &pg->pgpaths, list) { | |
1441 | DMEMIT("%s ", p->path.dev->name); | |
1442 | if (pg->ps.type->status) | |
1443 | sz += pg->ps.type->status(&pg->ps, | |
1444 | &p->path, type, result + sz, | |
1445 | maxlen - sz); | |
1446 | } | |
1447 | } | |
1448 | break; | |
1449 | } | |
1450 | ||
1451 | spin_unlock_irqrestore(&m->lock, flags); | |
1452 | ||
1453 | return 0; | |
1454 | } | |
1455 | ||
1456 | static int multipath_message(struct dm_target *ti, unsigned argc, char **argv) | |
1457 | { | |
6380f26f | 1458 | int r = -EINVAL; |
1da177e4 LT |
1459 | struct dm_dev *dev; |
1460 | struct multipath *m = (struct multipath *) ti->private; | |
1461 | action_fn action; | |
1462 | ||
6380f26f MA |
1463 | mutex_lock(&m->work_mutex); |
1464 | ||
c2f3d24b KU |
1465 | if (dm_suspended(ti)) { |
1466 | r = -EBUSY; | |
1467 | goto out; | |
1468 | } | |
1469 | ||
1da177e4 | 1470 | if (argc == 1) { |
498f0103 | 1471 | if (!strcasecmp(argv[0], "queue_if_no_path")) { |
6380f26f MA |
1472 | r = queue_if_no_path(m, 1, 0); |
1473 | goto out; | |
498f0103 | 1474 | } else if (!strcasecmp(argv[0], "fail_if_no_path")) { |
6380f26f MA |
1475 | r = queue_if_no_path(m, 0, 0); |
1476 | goto out; | |
1477 | } | |
1da177e4 LT |
1478 | } |
1479 | ||
6380f26f MA |
1480 | if (argc != 2) { |
1481 | DMWARN("Unrecognised multipath message received."); | |
1482 | goto out; | |
1483 | } | |
1da177e4 | 1484 | |
498f0103 | 1485 | if (!strcasecmp(argv[0], "disable_group")) { |
6380f26f MA |
1486 | r = bypass_pg_num(m, argv[1], 1); |
1487 | goto out; | |
498f0103 | 1488 | } else if (!strcasecmp(argv[0], "enable_group")) { |
6380f26f MA |
1489 | r = bypass_pg_num(m, argv[1], 0); |
1490 | goto out; | |
498f0103 | 1491 | } else if (!strcasecmp(argv[0], "switch_group")) { |
6380f26f MA |
1492 | r = switch_pg_num(m, argv[1]); |
1493 | goto out; | |
498f0103 | 1494 | } else if (!strcasecmp(argv[0], "reinstate_path")) |
1da177e4 | 1495 | action = reinstate_path; |
498f0103 | 1496 | else if (!strcasecmp(argv[0], "fail_path")) |
1da177e4 | 1497 | action = fail_path; |
6380f26f MA |
1498 | else { |
1499 | DMWARN("Unrecognised multipath message received."); | |
1500 | goto out; | |
1501 | } | |
1da177e4 | 1502 | |
8215d6ec | 1503 | r = dm_get_device(ti, argv[1], dm_table_get_mode(ti->table), &dev); |
1da177e4 | 1504 | if (r) { |
72d94861 | 1505 | DMWARN("message: error getting device %s", |
1da177e4 | 1506 | argv[1]); |
6380f26f | 1507 | goto out; |
1da177e4 LT |
1508 | } |
1509 | ||
1510 | r = action_dev(m, dev, action); | |
1511 | ||
1512 | dm_put_device(ti, dev); | |
1513 | ||
6380f26f MA |
1514 | out: |
1515 | mutex_unlock(&m->work_mutex); | |
1da177e4 | 1516 | return r; |
1da177e4 LT |
1517 | } |
1518 | ||
647b3d00 | 1519 | static int multipath_ioctl(struct dm_target *ti, unsigned int cmd, |
9af4aa30 MB |
1520 | unsigned long arg) |
1521 | { | |
35991652 MP |
1522 | struct multipath *m = ti->private; |
1523 | struct block_device *bdev; | |
1524 | fmode_t mode; | |
9af4aa30 | 1525 | unsigned long flags; |
35991652 MP |
1526 | int r; |
1527 | ||
1528 | again: | |
1529 | bdev = NULL; | |
1530 | mode = 0; | |
1531 | r = 0; | |
9af4aa30 MB |
1532 | |
1533 | spin_lock_irqsave(&m->lock, flags); | |
1534 | ||
1535 | if (!m->current_pgpath) | |
02ab823f | 1536 | __choose_pgpath(m, 0); |
9af4aa30 | 1537 | |
e90dae1f | 1538 | if (m->current_pgpath) { |
9af4aa30 | 1539 | bdev = m->current_pgpath->path.dev->bdev; |
633a08b8 | 1540 | mode = m->current_pgpath->path.dev->mode; |
e90dae1f | 1541 | } |
9af4aa30 MB |
1542 | |
1543 | if (m->queue_io) | |
1544 | r = -EAGAIN; | |
1545 | else if (!bdev) | |
1546 | r = -EIO; | |
1547 | ||
1548 | spin_unlock_irqrestore(&m->lock, flags); | |
1549 | ||
ec8013be PB |
1550 | /* |
1551 | * Only pass ioctls through if the device sizes match exactly. | |
1552 | */ | |
1553 | if (!r && ti->len != i_size_read(bdev->bd_inode) >> SECTOR_SHIFT) | |
1554 | r = scsi_verify_blk_ioctl(NULL, cmd); | |
1555 | ||
35991652 MP |
1556 | if (r == -EAGAIN && !fatal_signal_pending(current)) { |
1557 | queue_work(kmultipathd, &m->process_queued_ios); | |
1558 | msleep(10); | |
1559 | goto again; | |
1560 | } | |
1561 | ||
633a08b8 | 1562 | return r ? : __blkdev_driver_ioctl(bdev, mode, cmd, arg); |
9af4aa30 MB |
1563 | } |
1564 | ||
af4874e0 MS |
1565 | static int multipath_iterate_devices(struct dm_target *ti, |
1566 | iterate_devices_callout_fn fn, void *data) | |
1567 | { | |
1568 | struct multipath *m = ti->private; | |
1569 | struct priority_group *pg; | |
1570 | struct pgpath *p; | |
1571 | int ret = 0; | |
1572 | ||
1573 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1574 | list_for_each_entry(p, &pg->pgpaths, list) { | |
5dea271b | 1575 | ret = fn(ti, p->path.dev, ti->begin, ti->len, data); |
af4874e0 MS |
1576 | if (ret) |
1577 | goto out; | |
1578 | } | |
1579 | } | |
1580 | ||
1581 | out: | |
1582 | return ret; | |
1583 | } | |
1584 | ||
f40c67f0 KU |
1585 | static int __pgpath_busy(struct pgpath *pgpath) |
1586 | { | |
1587 | struct request_queue *q = bdev_get_queue(pgpath->path.dev->bdev); | |
1588 | ||
1589 | return dm_underlying_device_busy(q); | |
1590 | } | |
1591 | ||
1592 | /* | |
1593 | * We return "busy", only when we can map I/Os but underlying devices | |
1594 | * are busy (so even if we map I/Os now, the I/Os will wait on | |
1595 | * the underlying queue). | |
1596 | * In other words, if we want to kill I/Os or queue them inside us | |
1597 | * due to map unavailability, we don't return "busy". Otherwise, | |
1598 | * dm core won't give us the I/Os and we can't do what we want. | |
1599 | */ | |
1600 | static int multipath_busy(struct dm_target *ti) | |
1601 | { | |
1602 | int busy = 0, has_active = 0; | |
1603 | struct multipath *m = ti->private; | |
1604 | struct priority_group *pg; | |
1605 | struct pgpath *pgpath; | |
1606 | unsigned long flags; | |
1607 | ||
1608 | spin_lock_irqsave(&m->lock, flags); | |
1609 | ||
1610 | /* Guess which priority_group will be used at next mapping time */ | |
1611 | if (unlikely(!m->current_pgpath && m->next_pg)) | |
1612 | pg = m->next_pg; | |
1613 | else if (likely(m->current_pg)) | |
1614 | pg = m->current_pg; | |
1615 | else | |
1616 | /* | |
1617 | * We don't know which pg will be used at next mapping time. | |
1618 | * We don't call __choose_pgpath() here to avoid to trigger | |
1619 | * pg_init just by busy checking. | |
1620 | * So we don't know whether underlying devices we will be using | |
1621 | * at next mapping time are busy or not. Just try mapping. | |
1622 | */ | |
1623 | goto out; | |
1624 | ||
1625 | /* | |
1626 | * If there is one non-busy active path at least, the path selector | |
1627 | * will be able to select it. So we consider such a pg as not busy. | |
1628 | */ | |
1629 | busy = 1; | |
1630 | list_for_each_entry(pgpath, &pg->pgpaths, list) | |
1631 | if (pgpath->is_active) { | |
1632 | has_active = 1; | |
1633 | ||
1634 | if (!__pgpath_busy(pgpath)) { | |
1635 | busy = 0; | |
1636 | break; | |
1637 | } | |
1638 | } | |
1639 | ||
1640 | if (!has_active) | |
1641 | /* | |
1642 | * No active path in this pg, so this pg won't be used and | |
1643 | * the current_pg will be changed at next mapping time. | |
1644 | * We need to try mapping to determine it. | |
1645 | */ | |
1646 | busy = 0; | |
1647 | ||
1648 | out: | |
1649 | spin_unlock_irqrestore(&m->lock, flags); | |
1650 | ||
1651 | return busy; | |
1652 | } | |
1653 | ||
1da177e4 LT |
1654 | /*----------------------------------------------------------------- |
1655 | * Module setup | |
1656 | *---------------------------------------------------------------*/ | |
1657 | static struct target_type multipath_target = { | |
1658 | .name = "multipath", | |
35991652 | 1659 | .version = {1, 4, 0}, |
1da177e4 LT |
1660 | .module = THIS_MODULE, |
1661 | .ctr = multipath_ctr, | |
1662 | .dtr = multipath_dtr, | |
f40c67f0 KU |
1663 | .map_rq = multipath_map, |
1664 | .rq_end_io = multipath_end_io, | |
1da177e4 | 1665 | .presuspend = multipath_presuspend, |
6df400ab | 1666 | .postsuspend = multipath_postsuspend, |
1da177e4 LT |
1667 | .resume = multipath_resume, |
1668 | .status = multipath_status, | |
1669 | .message = multipath_message, | |
9af4aa30 | 1670 | .ioctl = multipath_ioctl, |
af4874e0 | 1671 | .iterate_devices = multipath_iterate_devices, |
f40c67f0 | 1672 | .busy = multipath_busy, |
1da177e4 LT |
1673 | }; |
1674 | ||
1675 | static int __init dm_multipath_init(void) | |
1676 | { | |
1677 | int r; | |
1678 | ||
1679 | /* allocate a slab for the dm_ios */ | |
028867ac | 1680 | _mpio_cache = KMEM_CACHE(dm_mpath_io, 0); |
1da177e4 LT |
1681 | if (!_mpio_cache) |
1682 | return -ENOMEM; | |
1683 | ||
1684 | r = dm_register_target(&multipath_target); | |
1685 | if (r < 0) { | |
0cd33124 | 1686 | DMERR("register failed %d", r); |
1da177e4 LT |
1687 | kmem_cache_destroy(_mpio_cache); |
1688 | return -EINVAL; | |
1689 | } | |
1690 | ||
4d4d66ab | 1691 | kmultipathd = alloc_workqueue("kmpathd", WQ_MEM_RECLAIM, 0); |
c557308e | 1692 | if (!kmultipathd) { |
0cd33124 | 1693 | DMERR("failed to create workqueue kmpathd"); |
c557308e AK |
1694 | dm_unregister_target(&multipath_target); |
1695 | kmem_cache_destroy(_mpio_cache); | |
1696 | return -ENOMEM; | |
1697 | } | |
1698 | ||
bab7cfc7 CS |
1699 | /* |
1700 | * A separate workqueue is used to handle the device handlers | |
1701 | * to avoid overloading existing workqueue. Overloading the | |
1702 | * old workqueue would also create a bottleneck in the | |
1703 | * path of the storage hardware device activation. | |
1704 | */ | |
4d4d66ab TH |
1705 | kmpath_handlerd = alloc_ordered_workqueue("kmpath_handlerd", |
1706 | WQ_MEM_RECLAIM); | |
bab7cfc7 CS |
1707 | if (!kmpath_handlerd) { |
1708 | DMERR("failed to create workqueue kmpath_handlerd"); | |
1709 | destroy_workqueue(kmultipathd); | |
1710 | dm_unregister_target(&multipath_target); | |
1711 | kmem_cache_destroy(_mpio_cache); | |
1712 | return -ENOMEM; | |
1713 | } | |
1714 | ||
72d94861 | 1715 | DMINFO("version %u.%u.%u loaded", |
1da177e4 LT |
1716 | multipath_target.version[0], multipath_target.version[1], |
1717 | multipath_target.version[2]); | |
1718 | ||
1719 | return r; | |
1720 | } | |
1721 | ||
1722 | static void __exit dm_multipath_exit(void) | |
1723 | { | |
bab7cfc7 | 1724 | destroy_workqueue(kmpath_handlerd); |
c557308e AK |
1725 | destroy_workqueue(kmultipathd); |
1726 | ||
10d3bd09 | 1727 | dm_unregister_target(&multipath_target); |
1da177e4 LT |
1728 | kmem_cache_destroy(_mpio_cache); |
1729 | } | |
1730 | ||
1da177e4 LT |
1731 | module_init(dm_multipath_init); |
1732 | module_exit(dm_multipath_exit); | |
1733 | ||
1734 | MODULE_DESCRIPTION(DM_NAME " multipath target"); | |
1735 | MODULE_AUTHOR("Sistina Software <dm-devel@redhat.com>"); | |
1736 | MODULE_LICENSE("GPL"); |