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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * Copyright (C) 2003 Sistina Software Limited. | |
3 | * Copyright (C) 2004-2005 Red Hat, Inc. All rights reserved. | |
4 | * | |
5 | * This file is released under the GPL. | |
6 | */ | |
7 | ||
586e80e6 MP |
8 | #include <linux/device-mapper.h> |
9 | ||
1da177e4 | 10 | #include "dm-path-selector.h" |
b15546f9 | 11 | #include "dm-uevent.h" |
1da177e4 LT |
12 | |
13 | #include <linux/ctype.h> | |
14 | #include <linux/init.h> | |
15 | #include <linux/mempool.h> | |
16 | #include <linux/module.h> | |
17 | #include <linux/pagemap.h> | |
18 | #include <linux/slab.h> | |
19 | #include <linux/time.h> | |
20 | #include <linux/workqueue.h> | |
cfae5c9b | 21 | #include <scsi/scsi_dh.h> |
60063497 | 22 | #include <linux/atomic.h> |
1da177e4 | 23 | |
72d94861 | 24 | #define DM_MSG_PREFIX "multipath" |
4e2d19e4 CS |
25 | #define DM_PG_INIT_DELAY_MSECS 2000 |
26 | #define DM_PG_INIT_DELAY_DEFAULT ((unsigned) -1) | |
1da177e4 LT |
27 | |
28 | /* Path properties */ | |
29 | struct pgpath { | |
30 | struct list_head list; | |
31 | ||
32 | struct priority_group *pg; /* Owning PG */ | |
6680073d | 33 | unsigned is_active; /* Path status */ |
1da177e4 LT |
34 | unsigned fail_count; /* Cumulative failure count */ |
35 | ||
c922d5f7 | 36 | struct dm_path path; |
4e2d19e4 | 37 | struct delayed_work activate_path; |
1da177e4 LT |
38 | }; |
39 | ||
40 | #define path_to_pgpath(__pgp) container_of((__pgp), struct pgpath, path) | |
41 | ||
42 | /* | |
43 | * Paths are grouped into Priority Groups and numbered from 1 upwards. | |
44 | * Each has a path selector which controls which path gets used. | |
45 | */ | |
46 | struct priority_group { | |
47 | struct list_head list; | |
48 | ||
49 | struct multipath *m; /* Owning multipath instance */ | |
50 | struct path_selector ps; | |
51 | ||
52 | unsigned pg_num; /* Reference number */ | |
53 | unsigned bypassed; /* Temporarily bypass this PG? */ | |
54 | ||
55 | unsigned nr_pgpaths; /* Number of paths in PG */ | |
56 | struct list_head pgpaths; | |
57 | }; | |
58 | ||
59 | /* Multipath context */ | |
60 | struct multipath { | |
61 | struct list_head list; | |
62 | struct dm_target *ti; | |
63 | ||
cfae5c9b | 64 | const char *hw_handler_name; |
2bfd2e13 | 65 | char *hw_handler_params; |
4e2d19e4 | 66 | |
1fbdd2b3 MS |
67 | spinlock_t lock; |
68 | ||
1da177e4 LT |
69 | unsigned nr_priority_groups; |
70 | struct list_head priority_groups; | |
4e2d19e4 CS |
71 | |
72 | wait_queue_head_t pg_init_wait; /* Wait for pg_init completion */ | |
73 | ||
1da177e4 | 74 | unsigned pg_init_required; /* pg_init needs calling? */ |
c3cd4f6b | 75 | unsigned pg_init_in_progress; /* Only one pg_init allowed at once */ |
4e2d19e4 | 76 | unsigned pg_init_delay_retry; /* Delay pg_init retry? */ |
1da177e4 LT |
77 | |
78 | unsigned nr_valid_paths; /* Total number of usable paths */ | |
79 | struct pgpath *current_pgpath; | |
80 | struct priority_group *current_pg; | |
81 | struct priority_group *next_pg; /* Switch to this PG if set */ | |
82 | unsigned repeat_count; /* I/Os left before calling PS again */ | |
83 | ||
1fbdd2b3 MS |
84 | unsigned queue_io:1; /* Must we queue all I/O? */ |
85 | unsigned queue_if_no_path:1; /* Queue I/O if last path fails? */ | |
86 | unsigned saved_queue_if_no_path:1; /* Saved state during suspension */ | |
87 | ||
c9e45581 DW |
88 | unsigned pg_init_retries; /* Number of times to retry pg_init */ |
89 | unsigned pg_init_count; /* Number of times pg_init called */ | |
4e2d19e4 | 90 | unsigned pg_init_delay_msecs; /* Number of msecs before pg_init retry */ |
1da177e4 | 91 | |
1fbdd2b3 | 92 | unsigned queue_size; |
1da177e4 | 93 | struct work_struct process_queued_ios; |
f40c67f0 | 94 | struct list_head queued_ios; |
1da177e4 LT |
95 | |
96 | struct work_struct trigger_event; | |
97 | ||
98 | /* | |
028867ac | 99 | * We must use a mempool of dm_mpath_io structs so that we |
1da177e4 LT |
100 | * can resubmit bios on error. |
101 | */ | |
102 | mempool_t *mpio_pool; | |
6380f26f MA |
103 | |
104 | struct mutex work_mutex; | |
1da177e4 LT |
105 | }; |
106 | ||
107 | /* | |
108 | * Context information attached to each bio we process. | |
109 | */ | |
028867ac | 110 | struct dm_mpath_io { |
1da177e4 | 111 | struct pgpath *pgpath; |
02ab823f | 112 | size_t nr_bytes; |
1da177e4 LT |
113 | }; |
114 | ||
115 | typedef int (*action_fn) (struct pgpath *pgpath); | |
116 | ||
117 | #define MIN_IOS 256 /* Mempool size */ | |
118 | ||
e18b890b | 119 | static struct kmem_cache *_mpio_cache; |
1da177e4 | 120 | |
bab7cfc7 | 121 | static struct workqueue_struct *kmultipathd, *kmpath_handlerd; |
c4028958 DH |
122 | static void process_queued_ios(struct work_struct *work); |
123 | static void trigger_event(struct work_struct *work); | |
bab7cfc7 | 124 | static void activate_path(struct work_struct *work); |
1da177e4 LT |
125 | |
126 | ||
127 | /*----------------------------------------------- | |
128 | * Allocation routines | |
129 | *-----------------------------------------------*/ | |
130 | ||
131 | static struct pgpath *alloc_pgpath(void) | |
132 | { | |
e69fae56 | 133 | struct pgpath *pgpath = kzalloc(sizeof(*pgpath), GFP_KERNEL); |
1da177e4 | 134 | |
224cb3e9 | 135 | if (pgpath) { |
6680073d | 136 | pgpath->is_active = 1; |
4e2d19e4 | 137 | INIT_DELAYED_WORK(&pgpath->activate_path, activate_path); |
224cb3e9 | 138 | } |
1da177e4 LT |
139 | |
140 | return pgpath; | |
141 | } | |
142 | ||
028867ac | 143 | static void free_pgpath(struct pgpath *pgpath) |
1da177e4 LT |
144 | { |
145 | kfree(pgpath); | |
146 | } | |
147 | ||
148 | static struct priority_group *alloc_priority_group(void) | |
149 | { | |
150 | struct priority_group *pg; | |
151 | ||
e69fae56 | 152 | pg = kzalloc(sizeof(*pg), GFP_KERNEL); |
1da177e4 | 153 | |
e69fae56 MM |
154 | if (pg) |
155 | INIT_LIST_HEAD(&pg->pgpaths); | |
1da177e4 LT |
156 | |
157 | return pg; | |
158 | } | |
159 | ||
160 | static void free_pgpaths(struct list_head *pgpaths, struct dm_target *ti) | |
161 | { | |
162 | struct pgpath *pgpath, *tmp; | |
ae11b1b3 | 163 | struct multipath *m = ti->private; |
1da177e4 LT |
164 | |
165 | list_for_each_entry_safe(pgpath, tmp, pgpaths, list) { | |
166 | list_del(&pgpath->list); | |
ae11b1b3 HR |
167 | if (m->hw_handler_name) |
168 | scsi_dh_detach(bdev_get_queue(pgpath->path.dev->bdev)); | |
1da177e4 LT |
169 | dm_put_device(ti, pgpath->path.dev); |
170 | free_pgpath(pgpath); | |
171 | } | |
172 | } | |
173 | ||
174 | static void free_priority_group(struct priority_group *pg, | |
175 | struct dm_target *ti) | |
176 | { | |
177 | struct path_selector *ps = &pg->ps; | |
178 | ||
179 | if (ps->type) { | |
180 | ps->type->destroy(ps); | |
181 | dm_put_path_selector(ps->type); | |
182 | } | |
183 | ||
184 | free_pgpaths(&pg->pgpaths, ti); | |
185 | kfree(pg); | |
186 | } | |
187 | ||
28f16c20 | 188 | static struct multipath *alloc_multipath(struct dm_target *ti) |
1da177e4 LT |
189 | { |
190 | struct multipath *m; | |
191 | ||
e69fae56 | 192 | m = kzalloc(sizeof(*m), GFP_KERNEL); |
1da177e4 | 193 | if (m) { |
1da177e4 | 194 | INIT_LIST_HEAD(&m->priority_groups); |
f40c67f0 | 195 | INIT_LIST_HEAD(&m->queued_ios); |
1da177e4 LT |
196 | spin_lock_init(&m->lock); |
197 | m->queue_io = 1; | |
4e2d19e4 | 198 | m->pg_init_delay_msecs = DM_PG_INIT_DELAY_DEFAULT; |
c4028958 DH |
199 | INIT_WORK(&m->process_queued_ios, process_queued_ios); |
200 | INIT_WORK(&m->trigger_event, trigger_event); | |
2bded7bd | 201 | init_waitqueue_head(&m->pg_init_wait); |
6380f26f | 202 | mutex_init(&m->work_mutex); |
93d2341c | 203 | m->mpio_pool = mempool_create_slab_pool(MIN_IOS, _mpio_cache); |
1da177e4 LT |
204 | if (!m->mpio_pool) { |
205 | kfree(m); | |
206 | return NULL; | |
207 | } | |
28f16c20 MM |
208 | m->ti = ti; |
209 | ti->private = m; | |
1da177e4 LT |
210 | } |
211 | ||
212 | return m; | |
213 | } | |
214 | ||
215 | static void free_multipath(struct multipath *m) | |
216 | { | |
217 | struct priority_group *pg, *tmp; | |
1da177e4 LT |
218 | |
219 | list_for_each_entry_safe(pg, tmp, &m->priority_groups, list) { | |
220 | list_del(&pg->list); | |
221 | free_priority_group(pg, m->ti); | |
222 | } | |
223 | ||
cfae5c9b | 224 | kfree(m->hw_handler_name); |
2bfd2e13 | 225 | kfree(m->hw_handler_params); |
1da177e4 LT |
226 | mempool_destroy(m->mpio_pool); |
227 | kfree(m); | |
228 | } | |
229 | ||
466891f9 JN |
230 | static int set_mapinfo(struct multipath *m, union map_info *info) |
231 | { | |
232 | struct dm_mpath_io *mpio; | |
233 | ||
234 | mpio = mempool_alloc(m->mpio_pool, GFP_ATOMIC); | |
235 | if (!mpio) | |
236 | return -ENOMEM; | |
237 | ||
238 | memset(mpio, 0, sizeof(*mpio)); | |
239 | info->ptr = mpio; | |
240 | ||
241 | return 0; | |
242 | } | |
243 | ||
244 | static void clear_mapinfo(struct multipath *m, union map_info *info) | |
245 | { | |
246 | struct dm_mpath_io *mpio = info->ptr; | |
247 | ||
248 | info->ptr = NULL; | |
249 | mempool_free(mpio, m->mpio_pool); | |
250 | } | |
1da177e4 LT |
251 | |
252 | /*----------------------------------------------- | |
253 | * Path selection | |
254 | *-----------------------------------------------*/ | |
255 | ||
fb612642 KU |
256 | static void __pg_init_all_paths(struct multipath *m) |
257 | { | |
258 | struct pgpath *pgpath; | |
4e2d19e4 | 259 | unsigned long pg_init_delay = 0; |
fb612642 KU |
260 | |
261 | m->pg_init_count++; | |
262 | m->pg_init_required = 0; | |
4e2d19e4 CS |
263 | if (m->pg_init_delay_retry) |
264 | pg_init_delay = msecs_to_jiffies(m->pg_init_delay_msecs != DM_PG_INIT_DELAY_DEFAULT ? | |
265 | m->pg_init_delay_msecs : DM_PG_INIT_DELAY_MSECS); | |
fb612642 KU |
266 | list_for_each_entry(pgpath, &m->current_pg->pgpaths, list) { |
267 | /* Skip failed paths */ | |
268 | if (!pgpath->is_active) | |
269 | continue; | |
4e2d19e4 CS |
270 | if (queue_delayed_work(kmpath_handlerd, &pgpath->activate_path, |
271 | pg_init_delay)) | |
fb612642 KU |
272 | m->pg_init_in_progress++; |
273 | } | |
274 | } | |
275 | ||
1da177e4 LT |
276 | static void __switch_pg(struct multipath *m, struct pgpath *pgpath) |
277 | { | |
1da177e4 LT |
278 | m->current_pg = pgpath->pg; |
279 | ||
280 | /* Must we initialise the PG first, and queue I/O till it's ready? */ | |
cfae5c9b | 281 | if (m->hw_handler_name) { |
1da177e4 LT |
282 | m->pg_init_required = 1; |
283 | m->queue_io = 1; | |
284 | } else { | |
285 | m->pg_init_required = 0; | |
286 | m->queue_io = 0; | |
287 | } | |
c9e45581 DW |
288 | |
289 | m->pg_init_count = 0; | |
1da177e4 LT |
290 | } |
291 | ||
02ab823f KU |
292 | static int __choose_path_in_pg(struct multipath *m, struct priority_group *pg, |
293 | size_t nr_bytes) | |
1da177e4 | 294 | { |
c922d5f7 | 295 | struct dm_path *path; |
1da177e4 | 296 | |
02ab823f | 297 | path = pg->ps.type->select_path(&pg->ps, &m->repeat_count, nr_bytes); |
1da177e4 LT |
298 | if (!path) |
299 | return -ENXIO; | |
300 | ||
301 | m->current_pgpath = path_to_pgpath(path); | |
302 | ||
303 | if (m->current_pg != pg) | |
304 | __switch_pg(m, m->current_pgpath); | |
305 | ||
306 | return 0; | |
307 | } | |
308 | ||
02ab823f | 309 | static void __choose_pgpath(struct multipath *m, size_t nr_bytes) |
1da177e4 LT |
310 | { |
311 | struct priority_group *pg; | |
312 | unsigned bypassed = 1; | |
313 | ||
314 | if (!m->nr_valid_paths) | |
315 | goto failed; | |
316 | ||
317 | /* Were we instructed to switch PG? */ | |
318 | if (m->next_pg) { | |
319 | pg = m->next_pg; | |
320 | m->next_pg = NULL; | |
02ab823f | 321 | if (!__choose_path_in_pg(m, pg, nr_bytes)) |
1da177e4 LT |
322 | return; |
323 | } | |
324 | ||
325 | /* Don't change PG until it has no remaining paths */ | |
02ab823f | 326 | if (m->current_pg && !__choose_path_in_pg(m, m->current_pg, nr_bytes)) |
1da177e4 LT |
327 | return; |
328 | ||
329 | /* | |
330 | * Loop through priority groups until we find a valid path. | |
331 | * First time we skip PGs marked 'bypassed'. | |
f220fd4e MC |
332 | * Second time we only try the ones we skipped, but set |
333 | * pg_init_delay_retry so we do not hammer controllers. | |
1da177e4 LT |
334 | */ |
335 | do { | |
336 | list_for_each_entry(pg, &m->priority_groups, list) { | |
337 | if (pg->bypassed == bypassed) | |
338 | continue; | |
f220fd4e MC |
339 | if (!__choose_path_in_pg(m, pg, nr_bytes)) { |
340 | if (!bypassed) | |
341 | m->pg_init_delay_retry = 1; | |
1da177e4 | 342 | return; |
f220fd4e | 343 | } |
1da177e4 LT |
344 | } |
345 | } while (bypassed--); | |
346 | ||
347 | failed: | |
348 | m->current_pgpath = NULL; | |
349 | m->current_pg = NULL; | |
350 | } | |
351 | ||
45e15720 KU |
352 | /* |
353 | * Check whether bios must be queued in the device-mapper core rather | |
354 | * than here in the target. | |
355 | * | |
356 | * m->lock must be held on entry. | |
357 | * | |
358 | * If m->queue_if_no_path and m->saved_queue_if_no_path hold the | |
359 | * same value then we are not between multipath_presuspend() | |
360 | * and multipath_resume() calls and we have no need to check | |
361 | * for the DMF_NOFLUSH_SUSPENDING flag. | |
362 | */ | |
363 | static int __must_push_back(struct multipath *m) | |
364 | { | |
365 | return (m->queue_if_no_path != m->saved_queue_if_no_path && | |
366 | dm_noflush_suspending(m->ti)); | |
367 | } | |
368 | ||
f40c67f0 | 369 | static int map_io(struct multipath *m, struct request *clone, |
466891f9 | 370 | union map_info *map_context, unsigned was_queued) |
1da177e4 | 371 | { |
d2a7ad29 | 372 | int r = DM_MAPIO_REMAPPED; |
f40c67f0 | 373 | size_t nr_bytes = blk_rq_bytes(clone); |
1da177e4 LT |
374 | unsigned long flags; |
375 | struct pgpath *pgpath; | |
f40c67f0 | 376 | struct block_device *bdev; |
466891f9 | 377 | struct dm_mpath_io *mpio = map_context->ptr; |
1da177e4 LT |
378 | |
379 | spin_lock_irqsave(&m->lock, flags); | |
380 | ||
381 | /* Do we need to select a new pgpath? */ | |
382 | if (!m->current_pgpath || | |
383 | (!m->queue_io && (m->repeat_count && --m->repeat_count == 0))) | |
02ab823f | 384 | __choose_pgpath(m, nr_bytes); |
1da177e4 LT |
385 | |
386 | pgpath = m->current_pgpath; | |
387 | ||
388 | if (was_queued) | |
389 | m->queue_size--; | |
390 | ||
391 | if ((pgpath && m->queue_io) || | |
436d4108 | 392 | (!pgpath && m->queue_if_no_path)) { |
1da177e4 | 393 | /* Queue for the daemon to resubmit */ |
f40c67f0 | 394 | list_add_tail(&clone->queuelist, &m->queued_ios); |
1da177e4 | 395 | m->queue_size++; |
c3cd4f6b AK |
396 | if ((m->pg_init_required && !m->pg_init_in_progress) || |
397 | !m->queue_io) | |
c557308e | 398 | queue_work(kmultipathd, &m->process_queued_ios); |
1da177e4 | 399 | pgpath = NULL; |
d2a7ad29 | 400 | r = DM_MAPIO_SUBMITTED; |
f40c67f0 KU |
401 | } else if (pgpath) { |
402 | bdev = pgpath->path.dev->bdev; | |
403 | clone->q = bdev_get_queue(bdev); | |
404 | clone->rq_disk = bdev->bd_disk; | |
405 | } else if (__must_push_back(m)) | |
45e15720 KU |
406 | r = DM_MAPIO_REQUEUE; |
407 | else | |
408 | r = -EIO; /* Failed */ | |
1da177e4 LT |
409 | |
410 | mpio->pgpath = pgpath; | |
02ab823f KU |
411 | mpio->nr_bytes = nr_bytes; |
412 | ||
413 | if (r == DM_MAPIO_REMAPPED && pgpath->pg->ps.type->start_io) | |
414 | pgpath->pg->ps.type->start_io(&pgpath->pg->ps, &pgpath->path, | |
415 | nr_bytes); | |
1da177e4 LT |
416 | |
417 | spin_unlock_irqrestore(&m->lock, flags); | |
418 | ||
419 | return r; | |
420 | } | |
421 | ||
422 | /* | |
423 | * If we run out of usable paths, should we queue I/O or error it? | |
424 | */ | |
485ef69e AK |
425 | static int queue_if_no_path(struct multipath *m, unsigned queue_if_no_path, |
426 | unsigned save_old_value) | |
1da177e4 LT |
427 | { |
428 | unsigned long flags; | |
429 | ||
430 | spin_lock_irqsave(&m->lock, flags); | |
431 | ||
485ef69e AK |
432 | if (save_old_value) |
433 | m->saved_queue_if_no_path = m->queue_if_no_path; | |
434 | else | |
435 | m->saved_queue_if_no_path = queue_if_no_path; | |
1da177e4 | 436 | m->queue_if_no_path = queue_if_no_path; |
c3cd4f6b | 437 | if (!m->queue_if_no_path && m->queue_size) |
c557308e | 438 | queue_work(kmultipathd, &m->process_queued_ios); |
1da177e4 LT |
439 | |
440 | spin_unlock_irqrestore(&m->lock, flags); | |
441 | ||
442 | return 0; | |
443 | } | |
444 | ||
445 | /*----------------------------------------------------------------- | |
446 | * The multipath daemon is responsible for resubmitting queued ios. | |
447 | *---------------------------------------------------------------*/ | |
448 | ||
449 | static void dispatch_queued_ios(struct multipath *m) | |
450 | { | |
451 | int r; | |
452 | unsigned long flags; | |
1da177e4 | 453 | union map_info *info; |
f40c67f0 KU |
454 | struct request *clone, *n; |
455 | LIST_HEAD(cl); | |
1da177e4 LT |
456 | |
457 | spin_lock_irqsave(&m->lock, flags); | |
f40c67f0 | 458 | list_splice_init(&m->queued_ios, &cl); |
1da177e4 LT |
459 | spin_unlock_irqrestore(&m->lock, flags); |
460 | ||
f40c67f0 KU |
461 | list_for_each_entry_safe(clone, n, &cl, queuelist) { |
462 | list_del_init(&clone->queuelist); | |
1da177e4 | 463 | |
f40c67f0 | 464 | info = dm_get_rq_mapinfo(clone); |
1da177e4 | 465 | |
466891f9 | 466 | r = map_io(m, clone, info, 1); |
f40c67f0 | 467 | if (r < 0) { |
466891f9 | 468 | clear_mapinfo(m, info); |
f40c67f0 KU |
469 | dm_kill_unmapped_request(clone, r); |
470 | } else if (r == DM_MAPIO_REMAPPED) | |
471 | dm_dispatch_request(clone); | |
472 | else if (r == DM_MAPIO_REQUEUE) { | |
466891f9 | 473 | clear_mapinfo(m, info); |
f40c67f0 KU |
474 | dm_requeue_unmapped_request(clone); |
475 | } | |
1da177e4 LT |
476 | } |
477 | } | |
478 | ||
c4028958 | 479 | static void process_queued_ios(struct work_struct *work) |
1da177e4 | 480 | { |
c4028958 DH |
481 | struct multipath *m = |
482 | container_of(work, struct multipath, process_queued_ios); | |
fb612642 | 483 | struct pgpath *pgpath = NULL; |
e54f77dd | 484 | unsigned must_queue = 1; |
1da177e4 LT |
485 | unsigned long flags; |
486 | ||
487 | spin_lock_irqsave(&m->lock, flags); | |
488 | ||
c3cd4f6b AK |
489 | if (!m->queue_size) |
490 | goto out; | |
491 | ||
1da177e4 | 492 | if (!m->current_pgpath) |
02ab823f | 493 | __choose_pgpath(m, 0); |
1da177e4 LT |
494 | |
495 | pgpath = m->current_pgpath; | |
496 | ||
c3cd4f6b AK |
497 | if ((pgpath && !m->queue_io) || |
498 | (!pgpath && !m->queue_if_no_path)) | |
499 | must_queue = 0; | |
1da177e4 | 500 | |
fb612642 KU |
501 | if (m->pg_init_required && !m->pg_init_in_progress && pgpath) |
502 | __pg_init_all_paths(m); | |
503 | ||
c3cd4f6b | 504 | out: |
1da177e4 | 505 | spin_unlock_irqrestore(&m->lock, flags); |
1da177e4 LT |
506 | if (!must_queue) |
507 | dispatch_queued_ios(m); | |
508 | } | |
509 | ||
510 | /* | |
511 | * An event is triggered whenever a path is taken out of use. | |
512 | * Includes path failure and PG bypass. | |
513 | */ | |
c4028958 | 514 | static void trigger_event(struct work_struct *work) |
1da177e4 | 515 | { |
c4028958 DH |
516 | struct multipath *m = |
517 | container_of(work, struct multipath, trigger_event); | |
1da177e4 LT |
518 | |
519 | dm_table_event(m->ti->table); | |
520 | } | |
521 | ||
522 | /*----------------------------------------------------------------- | |
523 | * Constructor/argument parsing: | |
524 | * <#multipath feature args> [<arg>]* | |
525 | * <#hw_handler args> [hw_handler [<arg>]*] | |
526 | * <#priority groups> | |
527 | * <initial priority group> | |
528 | * [<selector> <#selector args> [<arg>]* | |
529 | * <#paths> <#per-path selector args> | |
530 | * [<path> [<arg>]* ]+ ]+ | |
531 | *---------------------------------------------------------------*/ | |
498f0103 | 532 | static int parse_path_selector(struct dm_arg_set *as, struct priority_group *pg, |
1da177e4 LT |
533 | struct dm_target *ti) |
534 | { | |
535 | int r; | |
536 | struct path_selector_type *pst; | |
537 | unsigned ps_argc; | |
538 | ||
498f0103 | 539 | static struct dm_arg _args[] = { |
72d94861 | 540 | {0, 1024, "invalid number of path selector args"}, |
1da177e4 LT |
541 | }; |
542 | ||
498f0103 | 543 | pst = dm_get_path_selector(dm_shift_arg(as)); |
1da177e4 | 544 | if (!pst) { |
72d94861 | 545 | ti->error = "unknown path selector type"; |
1da177e4 LT |
546 | return -EINVAL; |
547 | } | |
548 | ||
498f0103 | 549 | r = dm_read_arg_group(_args, as, &ps_argc, &ti->error); |
371b2e34 MP |
550 | if (r) { |
551 | dm_put_path_selector(pst); | |
1da177e4 | 552 | return -EINVAL; |
371b2e34 | 553 | } |
1da177e4 LT |
554 | |
555 | r = pst->create(&pg->ps, ps_argc, as->argv); | |
556 | if (r) { | |
557 | dm_put_path_selector(pst); | |
72d94861 | 558 | ti->error = "path selector constructor failed"; |
1da177e4 LT |
559 | return r; |
560 | } | |
561 | ||
562 | pg->ps.type = pst; | |
498f0103 | 563 | dm_consume_args(as, ps_argc); |
1da177e4 LT |
564 | |
565 | return 0; | |
566 | } | |
567 | ||
498f0103 | 568 | static struct pgpath *parse_path(struct dm_arg_set *as, struct path_selector *ps, |
1da177e4 LT |
569 | struct dm_target *ti) |
570 | { | |
571 | int r; | |
572 | struct pgpath *p; | |
ae11b1b3 | 573 | struct multipath *m = ti->private; |
1da177e4 LT |
574 | |
575 | /* we need at least a path arg */ | |
576 | if (as->argc < 1) { | |
72d94861 | 577 | ti->error = "no device given"; |
01460f35 | 578 | return ERR_PTR(-EINVAL); |
1da177e4 LT |
579 | } |
580 | ||
581 | p = alloc_pgpath(); | |
582 | if (!p) | |
01460f35 | 583 | return ERR_PTR(-ENOMEM); |
1da177e4 | 584 | |
498f0103 | 585 | r = dm_get_device(ti, dm_shift_arg(as), dm_table_get_mode(ti->table), |
8215d6ec | 586 | &p->path.dev); |
1da177e4 | 587 | if (r) { |
72d94861 | 588 | ti->error = "error getting device"; |
1da177e4 LT |
589 | goto bad; |
590 | } | |
591 | ||
ae11b1b3 | 592 | if (m->hw_handler_name) { |
a0cf7ea9 HR |
593 | struct request_queue *q = bdev_get_queue(p->path.dev->bdev); |
594 | ||
595 | r = scsi_dh_attach(q, m->hw_handler_name); | |
596 | if (r == -EBUSY) { | |
597 | /* | |
598 | * Already attached to different hw_handler, | |
599 | * try to reattach with correct one. | |
600 | */ | |
601 | scsi_dh_detach(q); | |
602 | r = scsi_dh_attach(q, m->hw_handler_name); | |
603 | } | |
604 | ||
ae11b1b3 | 605 | if (r < 0) { |
a0cf7ea9 | 606 | ti->error = "error attaching hardware handler"; |
ae11b1b3 HR |
607 | dm_put_device(ti, p->path.dev); |
608 | goto bad; | |
609 | } | |
2bfd2e13 CS |
610 | |
611 | if (m->hw_handler_params) { | |
612 | r = scsi_dh_set_params(q, m->hw_handler_params); | |
613 | if (r < 0) { | |
614 | ti->error = "unable to set hardware " | |
615 | "handler parameters"; | |
616 | scsi_dh_detach(q); | |
617 | dm_put_device(ti, p->path.dev); | |
618 | goto bad; | |
619 | } | |
620 | } | |
ae11b1b3 HR |
621 | } |
622 | ||
1da177e4 LT |
623 | r = ps->type->add_path(ps, &p->path, as->argc, as->argv, &ti->error); |
624 | if (r) { | |
625 | dm_put_device(ti, p->path.dev); | |
626 | goto bad; | |
627 | } | |
628 | ||
629 | return p; | |
630 | ||
631 | bad: | |
632 | free_pgpath(p); | |
01460f35 | 633 | return ERR_PTR(r); |
1da177e4 LT |
634 | } |
635 | ||
498f0103 | 636 | static struct priority_group *parse_priority_group(struct dm_arg_set *as, |
28f16c20 | 637 | struct multipath *m) |
1da177e4 | 638 | { |
498f0103 | 639 | static struct dm_arg _args[] = { |
72d94861 AK |
640 | {1, 1024, "invalid number of paths"}, |
641 | {0, 1024, "invalid number of selector args"} | |
1da177e4 LT |
642 | }; |
643 | ||
644 | int r; | |
498f0103 | 645 | unsigned i, nr_selector_args, nr_args; |
1da177e4 | 646 | struct priority_group *pg; |
28f16c20 | 647 | struct dm_target *ti = m->ti; |
1da177e4 LT |
648 | |
649 | if (as->argc < 2) { | |
650 | as->argc = 0; | |
01460f35 BM |
651 | ti->error = "not enough priority group arguments"; |
652 | return ERR_PTR(-EINVAL); | |
1da177e4 LT |
653 | } |
654 | ||
655 | pg = alloc_priority_group(); | |
656 | if (!pg) { | |
72d94861 | 657 | ti->error = "couldn't allocate priority group"; |
01460f35 | 658 | return ERR_PTR(-ENOMEM); |
1da177e4 LT |
659 | } |
660 | pg->m = m; | |
661 | ||
662 | r = parse_path_selector(as, pg, ti); | |
663 | if (r) | |
664 | goto bad; | |
665 | ||
666 | /* | |
667 | * read the paths | |
668 | */ | |
498f0103 | 669 | r = dm_read_arg(_args, as, &pg->nr_pgpaths, &ti->error); |
1da177e4 LT |
670 | if (r) |
671 | goto bad; | |
672 | ||
498f0103 | 673 | r = dm_read_arg(_args + 1, as, &nr_selector_args, &ti->error); |
1da177e4 LT |
674 | if (r) |
675 | goto bad; | |
676 | ||
498f0103 | 677 | nr_args = 1 + nr_selector_args; |
1da177e4 LT |
678 | for (i = 0; i < pg->nr_pgpaths; i++) { |
679 | struct pgpath *pgpath; | |
498f0103 | 680 | struct dm_arg_set path_args; |
1da177e4 | 681 | |
498f0103 | 682 | if (as->argc < nr_args) { |
148acff6 | 683 | ti->error = "not enough path parameters"; |
6bbf79a1 | 684 | r = -EINVAL; |
1da177e4 | 685 | goto bad; |
148acff6 | 686 | } |
1da177e4 | 687 | |
498f0103 | 688 | path_args.argc = nr_args; |
1da177e4 LT |
689 | path_args.argv = as->argv; |
690 | ||
691 | pgpath = parse_path(&path_args, &pg->ps, ti); | |
01460f35 BM |
692 | if (IS_ERR(pgpath)) { |
693 | r = PTR_ERR(pgpath); | |
1da177e4 | 694 | goto bad; |
01460f35 | 695 | } |
1da177e4 LT |
696 | |
697 | pgpath->pg = pg; | |
698 | list_add_tail(&pgpath->list, &pg->pgpaths); | |
498f0103 | 699 | dm_consume_args(as, nr_args); |
1da177e4 LT |
700 | } |
701 | ||
702 | return pg; | |
703 | ||
704 | bad: | |
705 | free_priority_group(pg, ti); | |
01460f35 | 706 | return ERR_PTR(r); |
1da177e4 LT |
707 | } |
708 | ||
498f0103 | 709 | static int parse_hw_handler(struct dm_arg_set *as, struct multipath *m) |
1da177e4 | 710 | { |
1da177e4 | 711 | unsigned hw_argc; |
2bfd2e13 | 712 | int ret; |
28f16c20 | 713 | struct dm_target *ti = m->ti; |
1da177e4 | 714 | |
498f0103 | 715 | static struct dm_arg _args[] = { |
72d94861 | 716 | {0, 1024, "invalid number of hardware handler args"}, |
1da177e4 LT |
717 | }; |
718 | ||
498f0103 | 719 | if (dm_read_arg_group(_args, as, &hw_argc, &ti->error)) |
1da177e4 LT |
720 | return -EINVAL; |
721 | ||
722 | if (!hw_argc) | |
723 | return 0; | |
724 | ||
498f0103 | 725 | m->hw_handler_name = kstrdup(dm_shift_arg(as), GFP_KERNEL); |
510193a2 MS |
726 | if (!try_then_request_module(scsi_dh_handler_exist(m->hw_handler_name), |
727 | "scsi_dh_%s", m->hw_handler_name)) { | |
72d94861 | 728 | ti->error = "unknown hardware handler type"; |
2bfd2e13 CS |
729 | ret = -EINVAL; |
730 | goto fail; | |
1da177e4 | 731 | } |
14e98c5c | 732 | |
2bfd2e13 CS |
733 | if (hw_argc > 1) { |
734 | char *p; | |
735 | int i, j, len = 4; | |
736 | ||
737 | for (i = 0; i <= hw_argc - 2; i++) | |
738 | len += strlen(as->argv[i]) + 1; | |
739 | p = m->hw_handler_params = kzalloc(len, GFP_KERNEL); | |
740 | if (!p) { | |
741 | ti->error = "memory allocation failed"; | |
742 | ret = -ENOMEM; | |
743 | goto fail; | |
744 | } | |
745 | j = sprintf(p, "%d", hw_argc - 1); | |
746 | for (i = 0, p+=j+1; i <= hw_argc - 2; i++, p+=j+1) | |
747 | j = sprintf(p, "%s", as->argv[i]); | |
748 | } | |
498f0103 | 749 | dm_consume_args(as, hw_argc - 1); |
1da177e4 LT |
750 | |
751 | return 0; | |
2bfd2e13 CS |
752 | fail: |
753 | kfree(m->hw_handler_name); | |
754 | m->hw_handler_name = NULL; | |
755 | return ret; | |
1da177e4 LT |
756 | } |
757 | ||
498f0103 | 758 | static int parse_features(struct dm_arg_set *as, struct multipath *m) |
1da177e4 LT |
759 | { |
760 | int r; | |
761 | unsigned argc; | |
28f16c20 | 762 | struct dm_target *ti = m->ti; |
498f0103 | 763 | const char *arg_name; |
1da177e4 | 764 | |
498f0103 | 765 | static struct dm_arg _args[] = { |
4e2d19e4 | 766 | {0, 5, "invalid number of feature args"}, |
c9e45581 | 767 | {1, 50, "pg_init_retries must be between 1 and 50"}, |
4e2d19e4 | 768 | {0, 60000, "pg_init_delay_msecs must be between 0 and 60000"}, |
1da177e4 LT |
769 | }; |
770 | ||
498f0103 | 771 | r = dm_read_arg_group(_args, as, &argc, &ti->error); |
1da177e4 LT |
772 | if (r) |
773 | return -EINVAL; | |
774 | ||
775 | if (!argc) | |
776 | return 0; | |
777 | ||
c9e45581 | 778 | do { |
498f0103 | 779 | arg_name = dm_shift_arg(as); |
c9e45581 DW |
780 | argc--; |
781 | ||
498f0103 | 782 | if (!strcasecmp(arg_name, "queue_if_no_path")) { |
c9e45581 DW |
783 | r = queue_if_no_path(m, 1, 0); |
784 | continue; | |
785 | } | |
786 | ||
498f0103 | 787 | if (!strcasecmp(arg_name, "pg_init_retries") && |
c9e45581 | 788 | (argc >= 1)) { |
498f0103 | 789 | r = dm_read_arg(_args + 1, as, &m->pg_init_retries, &ti->error); |
c9e45581 DW |
790 | argc--; |
791 | continue; | |
792 | } | |
793 | ||
498f0103 | 794 | if (!strcasecmp(arg_name, "pg_init_delay_msecs") && |
4e2d19e4 | 795 | (argc >= 1)) { |
498f0103 | 796 | r = dm_read_arg(_args + 2, as, &m->pg_init_delay_msecs, &ti->error); |
4e2d19e4 CS |
797 | argc--; |
798 | continue; | |
799 | } | |
800 | ||
1da177e4 | 801 | ti->error = "Unrecognised multipath feature request"; |
c9e45581 DW |
802 | r = -EINVAL; |
803 | } while (argc && !r); | |
804 | ||
805 | return r; | |
1da177e4 LT |
806 | } |
807 | ||
808 | static int multipath_ctr(struct dm_target *ti, unsigned int argc, | |
809 | char **argv) | |
810 | { | |
498f0103 MS |
811 | /* target arguments */ |
812 | static struct dm_arg _args[] = { | |
a490a07a MS |
813 | {0, 1024, "invalid number of priority groups"}, |
814 | {0, 1024, "invalid initial priority group number"}, | |
1da177e4 LT |
815 | }; |
816 | ||
817 | int r; | |
818 | struct multipath *m; | |
498f0103 | 819 | struct dm_arg_set as; |
1da177e4 LT |
820 | unsigned pg_count = 0; |
821 | unsigned next_pg_num; | |
822 | ||
823 | as.argc = argc; | |
824 | as.argv = argv; | |
825 | ||
28f16c20 | 826 | m = alloc_multipath(ti); |
1da177e4 | 827 | if (!m) { |
72d94861 | 828 | ti->error = "can't allocate multipath"; |
1da177e4 LT |
829 | return -EINVAL; |
830 | } | |
831 | ||
28f16c20 | 832 | r = parse_features(&as, m); |
1da177e4 LT |
833 | if (r) |
834 | goto bad; | |
835 | ||
28f16c20 | 836 | r = parse_hw_handler(&as, m); |
1da177e4 LT |
837 | if (r) |
838 | goto bad; | |
839 | ||
498f0103 | 840 | r = dm_read_arg(_args, &as, &m->nr_priority_groups, &ti->error); |
1da177e4 LT |
841 | if (r) |
842 | goto bad; | |
843 | ||
498f0103 | 844 | r = dm_read_arg(_args + 1, &as, &next_pg_num, &ti->error); |
1da177e4 LT |
845 | if (r) |
846 | goto bad; | |
847 | ||
a490a07a MS |
848 | if ((!m->nr_priority_groups && next_pg_num) || |
849 | (m->nr_priority_groups && !next_pg_num)) { | |
850 | ti->error = "invalid initial priority group"; | |
851 | r = -EINVAL; | |
852 | goto bad; | |
853 | } | |
854 | ||
1da177e4 LT |
855 | /* parse the priority groups */ |
856 | while (as.argc) { | |
857 | struct priority_group *pg; | |
858 | ||
28f16c20 | 859 | pg = parse_priority_group(&as, m); |
01460f35 BM |
860 | if (IS_ERR(pg)) { |
861 | r = PTR_ERR(pg); | |
1da177e4 LT |
862 | goto bad; |
863 | } | |
864 | ||
865 | m->nr_valid_paths += pg->nr_pgpaths; | |
866 | list_add_tail(&pg->list, &m->priority_groups); | |
867 | pg_count++; | |
868 | pg->pg_num = pg_count; | |
869 | if (!--next_pg_num) | |
870 | m->next_pg = pg; | |
871 | } | |
872 | ||
873 | if (pg_count != m->nr_priority_groups) { | |
72d94861 | 874 | ti->error = "priority group count mismatch"; |
1da177e4 LT |
875 | r = -EINVAL; |
876 | goto bad; | |
877 | } | |
878 | ||
8627921f | 879 | ti->num_flush_requests = 1; |
959eb4e5 | 880 | ti->num_discard_requests = 1; |
8627921f | 881 | |
1da177e4 LT |
882 | return 0; |
883 | ||
884 | bad: | |
885 | free_multipath(m); | |
886 | return r; | |
887 | } | |
888 | ||
2bded7bd KU |
889 | static void multipath_wait_for_pg_init_completion(struct multipath *m) |
890 | { | |
891 | DECLARE_WAITQUEUE(wait, current); | |
892 | unsigned long flags; | |
893 | ||
894 | add_wait_queue(&m->pg_init_wait, &wait); | |
895 | ||
896 | while (1) { | |
897 | set_current_state(TASK_UNINTERRUPTIBLE); | |
898 | ||
899 | spin_lock_irqsave(&m->lock, flags); | |
900 | if (!m->pg_init_in_progress) { | |
901 | spin_unlock_irqrestore(&m->lock, flags); | |
902 | break; | |
903 | } | |
904 | spin_unlock_irqrestore(&m->lock, flags); | |
905 | ||
906 | io_schedule(); | |
907 | } | |
908 | set_current_state(TASK_RUNNING); | |
909 | ||
910 | remove_wait_queue(&m->pg_init_wait, &wait); | |
911 | } | |
912 | ||
913 | static void flush_multipath_work(struct multipath *m) | |
1da177e4 | 914 | { |
bab7cfc7 | 915 | flush_workqueue(kmpath_handlerd); |
2bded7bd | 916 | multipath_wait_for_pg_init_completion(m); |
a044d016 | 917 | flush_workqueue(kmultipathd); |
d5ffa387 | 918 | flush_work_sync(&m->trigger_event); |
6df400ab KU |
919 | } |
920 | ||
921 | static void multipath_dtr(struct dm_target *ti) | |
922 | { | |
923 | struct multipath *m = ti->private; | |
924 | ||
2bded7bd | 925 | flush_multipath_work(m); |
1da177e4 LT |
926 | free_multipath(m); |
927 | } | |
928 | ||
929 | /* | |
f40c67f0 | 930 | * Map cloned requests |
1da177e4 | 931 | */ |
f40c67f0 | 932 | static int multipath_map(struct dm_target *ti, struct request *clone, |
1da177e4 LT |
933 | union map_info *map_context) |
934 | { | |
935 | int r; | |
1da177e4 LT |
936 | struct multipath *m = (struct multipath *) ti->private; |
937 | ||
466891f9 | 938 | if (set_mapinfo(m, map_context) < 0) |
f40c67f0 KU |
939 | /* ENOMEM, requeue */ |
940 | return DM_MAPIO_REQUEUE; | |
1da177e4 | 941 | |
f40c67f0 | 942 | clone->cmd_flags |= REQ_FAILFAST_TRANSPORT; |
466891f9 | 943 | r = map_io(m, clone, map_context, 0); |
45e15720 | 944 | if (r < 0 || r == DM_MAPIO_REQUEUE) |
466891f9 | 945 | clear_mapinfo(m, map_context); |
1da177e4 LT |
946 | |
947 | return r; | |
948 | } | |
949 | ||
950 | /* | |
951 | * Take a path out of use. | |
952 | */ | |
953 | static int fail_path(struct pgpath *pgpath) | |
954 | { | |
955 | unsigned long flags; | |
956 | struct multipath *m = pgpath->pg->m; | |
957 | ||
958 | spin_lock_irqsave(&m->lock, flags); | |
959 | ||
6680073d | 960 | if (!pgpath->is_active) |
1da177e4 LT |
961 | goto out; |
962 | ||
72d94861 | 963 | DMWARN("Failing path %s.", pgpath->path.dev->name); |
1da177e4 LT |
964 | |
965 | pgpath->pg->ps.type->fail_path(&pgpath->pg->ps, &pgpath->path); | |
6680073d | 966 | pgpath->is_active = 0; |
1da177e4 LT |
967 | pgpath->fail_count++; |
968 | ||
969 | m->nr_valid_paths--; | |
970 | ||
971 | if (pgpath == m->current_pgpath) | |
972 | m->current_pgpath = NULL; | |
973 | ||
b15546f9 MA |
974 | dm_path_uevent(DM_UEVENT_PATH_FAILED, m->ti, |
975 | pgpath->path.dev->name, m->nr_valid_paths); | |
976 | ||
fe9cf30e | 977 | schedule_work(&m->trigger_event); |
1da177e4 LT |
978 | |
979 | out: | |
980 | spin_unlock_irqrestore(&m->lock, flags); | |
981 | ||
982 | return 0; | |
983 | } | |
984 | ||
985 | /* | |
986 | * Reinstate a previously-failed path | |
987 | */ | |
988 | static int reinstate_path(struct pgpath *pgpath) | |
989 | { | |
990 | int r = 0; | |
991 | unsigned long flags; | |
992 | struct multipath *m = pgpath->pg->m; | |
993 | ||
994 | spin_lock_irqsave(&m->lock, flags); | |
995 | ||
6680073d | 996 | if (pgpath->is_active) |
1da177e4 LT |
997 | goto out; |
998 | ||
def052d2 | 999 | if (!pgpath->pg->ps.type->reinstate_path) { |
1da177e4 LT |
1000 | DMWARN("Reinstate path not supported by path selector %s", |
1001 | pgpath->pg->ps.type->name); | |
1002 | r = -EINVAL; | |
1003 | goto out; | |
1004 | } | |
1005 | ||
1006 | r = pgpath->pg->ps.type->reinstate_path(&pgpath->pg->ps, &pgpath->path); | |
1007 | if (r) | |
1008 | goto out; | |
1009 | ||
6680073d | 1010 | pgpath->is_active = 1; |
1da177e4 | 1011 | |
e54f77dd CS |
1012 | if (!m->nr_valid_paths++ && m->queue_size) { |
1013 | m->current_pgpath = NULL; | |
c557308e | 1014 | queue_work(kmultipathd, &m->process_queued_ios); |
e54f77dd | 1015 | } else if (m->hw_handler_name && (m->current_pg == pgpath->pg)) { |
4e2d19e4 | 1016 | if (queue_work(kmpath_handlerd, &pgpath->activate_path.work)) |
e54f77dd CS |
1017 | m->pg_init_in_progress++; |
1018 | } | |
1da177e4 | 1019 | |
b15546f9 MA |
1020 | dm_path_uevent(DM_UEVENT_PATH_REINSTATED, m->ti, |
1021 | pgpath->path.dev->name, m->nr_valid_paths); | |
1022 | ||
fe9cf30e | 1023 | schedule_work(&m->trigger_event); |
1da177e4 LT |
1024 | |
1025 | out: | |
1026 | spin_unlock_irqrestore(&m->lock, flags); | |
1027 | ||
1028 | return r; | |
1029 | } | |
1030 | ||
1031 | /* | |
1032 | * Fail or reinstate all paths that match the provided struct dm_dev. | |
1033 | */ | |
1034 | static int action_dev(struct multipath *m, struct dm_dev *dev, | |
1035 | action_fn action) | |
1036 | { | |
19040c0b | 1037 | int r = -EINVAL; |
1da177e4 LT |
1038 | struct pgpath *pgpath; |
1039 | struct priority_group *pg; | |
1040 | ||
1041 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1042 | list_for_each_entry(pgpath, &pg->pgpaths, list) { | |
1043 | if (pgpath->path.dev == dev) | |
1044 | r = action(pgpath); | |
1045 | } | |
1046 | } | |
1047 | ||
1048 | return r; | |
1049 | } | |
1050 | ||
1051 | /* | |
1052 | * Temporarily try to avoid having to use the specified PG | |
1053 | */ | |
1054 | static void bypass_pg(struct multipath *m, struct priority_group *pg, | |
1055 | int bypassed) | |
1056 | { | |
1057 | unsigned long flags; | |
1058 | ||
1059 | spin_lock_irqsave(&m->lock, flags); | |
1060 | ||
1061 | pg->bypassed = bypassed; | |
1062 | m->current_pgpath = NULL; | |
1063 | m->current_pg = NULL; | |
1064 | ||
1065 | spin_unlock_irqrestore(&m->lock, flags); | |
1066 | ||
fe9cf30e | 1067 | schedule_work(&m->trigger_event); |
1da177e4 LT |
1068 | } |
1069 | ||
1070 | /* | |
1071 | * Switch to using the specified PG from the next I/O that gets mapped | |
1072 | */ | |
1073 | static int switch_pg_num(struct multipath *m, const char *pgstr) | |
1074 | { | |
1075 | struct priority_group *pg; | |
1076 | unsigned pgnum; | |
1077 | unsigned long flags; | |
31998ef1 | 1078 | char dummy; |
1da177e4 | 1079 | |
31998ef1 | 1080 | if (!pgstr || (sscanf(pgstr, "%u%c", &pgnum, &dummy) != 1) || !pgnum || |
1da177e4 LT |
1081 | (pgnum > m->nr_priority_groups)) { |
1082 | DMWARN("invalid PG number supplied to switch_pg_num"); | |
1083 | return -EINVAL; | |
1084 | } | |
1085 | ||
1086 | spin_lock_irqsave(&m->lock, flags); | |
1087 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1088 | pg->bypassed = 0; | |
1089 | if (--pgnum) | |
1090 | continue; | |
1091 | ||
1092 | m->current_pgpath = NULL; | |
1093 | m->current_pg = NULL; | |
1094 | m->next_pg = pg; | |
1095 | } | |
1096 | spin_unlock_irqrestore(&m->lock, flags); | |
1097 | ||
fe9cf30e | 1098 | schedule_work(&m->trigger_event); |
1da177e4 LT |
1099 | return 0; |
1100 | } | |
1101 | ||
1102 | /* | |
1103 | * Set/clear bypassed status of a PG. | |
1104 | * PGs are numbered upwards from 1 in the order they were declared. | |
1105 | */ | |
1106 | static int bypass_pg_num(struct multipath *m, const char *pgstr, int bypassed) | |
1107 | { | |
1108 | struct priority_group *pg; | |
1109 | unsigned pgnum; | |
31998ef1 | 1110 | char dummy; |
1da177e4 | 1111 | |
31998ef1 | 1112 | if (!pgstr || (sscanf(pgstr, "%u%c", &pgnum, &dummy) != 1) || !pgnum || |
1da177e4 LT |
1113 | (pgnum > m->nr_priority_groups)) { |
1114 | DMWARN("invalid PG number supplied to bypass_pg"); | |
1115 | return -EINVAL; | |
1116 | } | |
1117 | ||
1118 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1119 | if (!--pgnum) | |
1120 | break; | |
1121 | } | |
1122 | ||
1123 | bypass_pg(m, pg, bypassed); | |
1124 | return 0; | |
1125 | } | |
1126 | ||
c9e45581 DW |
1127 | /* |
1128 | * Should we retry pg_init immediately? | |
1129 | */ | |
1130 | static int pg_init_limit_reached(struct multipath *m, struct pgpath *pgpath) | |
1131 | { | |
1132 | unsigned long flags; | |
1133 | int limit_reached = 0; | |
1134 | ||
1135 | spin_lock_irqsave(&m->lock, flags); | |
1136 | ||
1137 | if (m->pg_init_count <= m->pg_init_retries) | |
1138 | m->pg_init_required = 1; | |
1139 | else | |
1140 | limit_reached = 1; | |
1141 | ||
1142 | spin_unlock_irqrestore(&m->lock, flags); | |
1143 | ||
1144 | return limit_reached; | |
1145 | } | |
1146 | ||
3ae31f6a | 1147 | static void pg_init_done(void *data, int errors) |
cfae5c9b | 1148 | { |
83c0d5d5 | 1149 | struct pgpath *pgpath = data; |
cfae5c9b CS |
1150 | struct priority_group *pg = pgpath->pg; |
1151 | struct multipath *m = pg->m; | |
1152 | unsigned long flags; | |
4e2d19e4 | 1153 | unsigned delay_retry = 0; |
cfae5c9b CS |
1154 | |
1155 | /* device or driver problems */ | |
1156 | switch (errors) { | |
1157 | case SCSI_DH_OK: | |
1158 | break; | |
1159 | case SCSI_DH_NOSYS: | |
1160 | if (!m->hw_handler_name) { | |
1161 | errors = 0; | |
1162 | break; | |
1163 | } | |
f7b934c8 MB |
1164 | DMERR("Could not failover the device: Handler scsi_dh_%s " |
1165 | "Error %d.", m->hw_handler_name, errors); | |
cfae5c9b CS |
1166 | /* |
1167 | * Fail path for now, so we do not ping pong | |
1168 | */ | |
1169 | fail_path(pgpath); | |
1170 | break; | |
1171 | case SCSI_DH_DEV_TEMP_BUSY: | |
1172 | /* | |
1173 | * Probably doing something like FW upgrade on the | |
1174 | * controller so try the other pg. | |
1175 | */ | |
1176 | bypass_pg(m, pg, 1); | |
1177 | break; | |
cfae5c9b | 1178 | case SCSI_DH_RETRY: |
4e2d19e4 CS |
1179 | /* Wait before retrying. */ |
1180 | delay_retry = 1; | |
cfae5c9b CS |
1181 | case SCSI_DH_IMM_RETRY: |
1182 | case SCSI_DH_RES_TEMP_UNAVAIL: | |
1183 | if (pg_init_limit_reached(m, pgpath)) | |
1184 | fail_path(pgpath); | |
1185 | errors = 0; | |
1186 | break; | |
1187 | default: | |
1188 | /* | |
1189 | * We probably do not want to fail the path for a device | |
1190 | * error, but this is what the old dm did. In future | |
1191 | * patches we can do more advanced handling. | |
1192 | */ | |
1193 | fail_path(pgpath); | |
1194 | } | |
1195 | ||
1196 | spin_lock_irqsave(&m->lock, flags); | |
1197 | if (errors) { | |
e54f77dd CS |
1198 | if (pgpath == m->current_pgpath) { |
1199 | DMERR("Could not failover device. Error %d.", errors); | |
1200 | m->current_pgpath = NULL; | |
1201 | m->current_pg = NULL; | |
1202 | } | |
d0259bf0 | 1203 | } else if (!m->pg_init_required) |
cfae5c9b | 1204 | pg->bypassed = 0; |
cfae5c9b | 1205 | |
d0259bf0 KU |
1206 | if (--m->pg_init_in_progress) |
1207 | /* Activations of other paths are still on going */ | |
1208 | goto out; | |
1209 | ||
1210 | if (!m->pg_init_required) | |
1211 | m->queue_io = 0; | |
1212 | ||
4e2d19e4 | 1213 | m->pg_init_delay_retry = delay_retry; |
d0259bf0 KU |
1214 | queue_work(kmultipathd, &m->process_queued_ios); |
1215 | ||
2bded7bd KU |
1216 | /* |
1217 | * Wake up any thread waiting to suspend. | |
1218 | */ | |
1219 | wake_up(&m->pg_init_wait); | |
1220 | ||
d0259bf0 | 1221 | out: |
cfae5c9b CS |
1222 | spin_unlock_irqrestore(&m->lock, flags); |
1223 | } | |
1224 | ||
bab7cfc7 CS |
1225 | static void activate_path(struct work_struct *work) |
1226 | { | |
e54f77dd | 1227 | struct pgpath *pgpath = |
4e2d19e4 | 1228 | container_of(work, struct pgpath, activate_path.work); |
bab7cfc7 | 1229 | |
3ae31f6a | 1230 | scsi_dh_activate(bdev_get_queue(pgpath->path.dev->bdev), |
83c0d5d5 | 1231 | pg_init_done, pgpath); |
bab7cfc7 CS |
1232 | } |
1233 | ||
1da177e4 LT |
1234 | /* |
1235 | * end_io handling | |
1236 | */ | |
f40c67f0 | 1237 | static int do_end_io(struct multipath *m, struct request *clone, |
028867ac | 1238 | int error, struct dm_mpath_io *mpio) |
1da177e4 | 1239 | { |
f40c67f0 KU |
1240 | /* |
1241 | * We don't queue any clone request inside the multipath target | |
1242 | * during end I/O handling, since those clone requests don't have | |
1243 | * bio clones. If we queue them inside the multipath target, | |
1244 | * we need to make bio clones, that requires memory allocation. | |
1245 | * (See drivers/md/dm.c:end_clone_bio() about why the clone requests | |
1246 | * don't have bio clones.) | |
1247 | * Instead of queueing the clone request here, we queue the original | |
1248 | * request into dm core, which will remake a clone request and | |
1249 | * clone bios for it and resubmit it later. | |
1250 | */ | |
1251 | int r = DM_ENDIO_REQUEUE; | |
640eb3b0 | 1252 | unsigned long flags; |
1da177e4 | 1253 | |
f40c67f0 | 1254 | if (!error && !clone->errors) |
1da177e4 LT |
1255 | return 0; /* I/O complete */ |
1256 | ||
6f13f6fb | 1257 | if (error == -EOPNOTSUPP || error == -EREMOTEIO || error == -EILSEQ) |
959eb4e5 MS |
1258 | return error; |
1259 | ||
cfae5c9b CS |
1260 | if (mpio->pgpath) |
1261 | fail_path(mpio->pgpath); | |
1da177e4 | 1262 | |
640eb3b0 | 1263 | spin_lock_irqsave(&m->lock, flags); |
751b2a7d HR |
1264 | if (!m->nr_valid_paths) { |
1265 | if (!m->queue_if_no_path) { | |
1266 | if (!__must_push_back(m)) | |
1267 | r = -EIO; | |
1268 | } else { | |
1269 | if (error == -EBADE) | |
1270 | r = error; | |
1271 | } | |
1272 | } | |
640eb3b0 | 1273 | spin_unlock_irqrestore(&m->lock, flags); |
1da177e4 | 1274 | |
f40c67f0 | 1275 | return r; |
1da177e4 LT |
1276 | } |
1277 | ||
f40c67f0 | 1278 | static int multipath_end_io(struct dm_target *ti, struct request *clone, |
1da177e4 LT |
1279 | int error, union map_info *map_context) |
1280 | { | |
028867ac AK |
1281 | struct multipath *m = ti->private; |
1282 | struct dm_mpath_io *mpio = map_context->ptr; | |
1da177e4 LT |
1283 | struct pgpath *pgpath = mpio->pgpath; |
1284 | struct path_selector *ps; | |
1285 | int r; | |
1286 | ||
466891f9 JN |
1287 | BUG_ON(!mpio); |
1288 | ||
f40c67f0 | 1289 | r = do_end_io(m, clone, error, mpio); |
1da177e4 LT |
1290 | if (pgpath) { |
1291 | ps = &pgpath->pg->ps; | |
1292 | if (ps->type->end_io) | |
02ab823f | 1293 | ps->type->end_io(ps, &pgpath->path, mpio->nr_bytes); |
1da177e4 | 1294 | } |
466891f9 | 1295 | clear_mapinfo(m, map_context); |
1da177e4 LT |
1296 | |
1297 | return r; | |
1298 | } | |
1299 | ||
1300 | /* | |
1301 | * Suspend can't complete until all the I/O is processed so if | |
436d4108 AK |
1302 | * the last path fails we must error any remaining I/O. |
1303 | * Note that if the freeze_bdev fails while suspending, the | |
1304 | * queue_if_no_path state is lost - userspace should reset it. | |
1da177e4 LT |
1305 | */ |
1306 | static void multipath_presuspend(struct dm_target *ti) | |
1307 | { | |
1308 | struct multipath *m = (struct multipath *) ti->private; | |
1da177e4 | 1309 | |
485ef69e | 1310 | queue_if_no_path(m, 0, 1); |
1da177e4 LT |
1311 | } |
1312 | ||
6df400ab KU |
1313 | static void multipath_postsuspend(struct dm_target *ti) |
1314 | { | |
6380f26f MA |
1315 | struct multipath *m = ti->private; |
1316 | ||
1317 | mutex_lock(&m->work_mutex); | |
2bded7bd | 1318 | flush_multipath_work(m); |
6380f26f | 1319 | mutex_unlock(&m->work_mutex); |
6df400ab KU |
1320 | } |
1321 | ||
436d4108 AK |
1322 | /* |
1323 | * Restore the queue_if_no_path setting. | |
1324 | */ | |
1da177e4 LT |
1325 | static void multipath_resume(struct dm_target *ti) |
1326 | { | |
1327 | struct multipath *m = (struct multipath *) ti->private; | |
1328 | unsigned long flags; | |
1329 | ||
1330 | spin_lock_irqsave(&m->lock, flags); | |
436d4108 | 1331 | m->queue_if_no_path = m->saved_queue_if_no_path; |
1da177e4 LT |
1332 | spin_unlock_irqrestore(&m->lock, flags); |
1333 | } | |
1334 | ||
1335 | /* | |
1336 | * Info output has the following format: | |
1337 | * num_multipath_feature_args [multipath_feature_args]* | |
1338 | * num_handler_status_args [handler_status_args]* | |
1339 | * num_groups init_group_number | |
1340 | * [A|D|E num_ps_status_args [ps_status_args]* | |
1341 | * num_paths num_selector_args | |
1342 | * [path_dev A|F fail_count [selector_args]* ]+ ]+ | |
1343 | * | |
1344 | * Table output has the following format (identical to the constructor string): | |
1345 | * num_feature_args [features_args]* | |
1346 | * num_handler_args hw_handler [hw_handler_args]* | |
1347 | * num_groups init_group_number | |
1348 | * [priority selector-name num_ps_args [ps_args]* | |
1349 | * num_paths num_selector_args [path_dev [selector_args]* ]+ ]+ | |
1350 | */ | |
1351 | static int multipath_status(struct dm_target *ti, status_type_t type, | |
1352 | char *result, unsigned int maxlen) | |
1353 | { | |
1354 | int sz = 0; | |
1355 | unsigned long flags; | |
1356 | struct multipath *m = (struct multipath *) ti->private; | |
1da177e4 LT |
1357 | struct priority_group *pg; |
1358 | struct pgpath *p; | |
1359 | unsigned pg_num; | |
1360 | char state; | |
1361 | ||
1362 | spin_lock_irqsave(&m->lock, flags); | |
1363 | ||
1364 | /* Features */ | |
1365 | if (type == STATUSTYPE_INFO) | |
c9e45581 DW |
1366 | DMEMIT("2 %u %u ", m->queue_size, m->pg_init_count); |
1367 | else { | |
1368 | DMEMIT("%u ", m->queue_if_no_path + | |
4e2d19e4 CS |
1369 | (m->pg_init_retries > 0) * 2 + |
1370 | (m->pg_init_delay_msecs != DM_PG_INIT_DELAY_DEFAULT) * 2); | |
c9e45581 DW |
1371 | if (m->queue_if_no_path) |
1372 | DMEMIT("queue_if_no_path "); | |
1373 | if (m->pg_init_retries) | |
1374 | DMEMIT("pg_init_retries %u ", m->pg_init_retries); | |
4e2d19e4 CS |
1375 | if (m->pg_init_delay_msecs != DM_PG_INIT_DELAY_DEFAULT) |
1376 | DMEMIT("pg_init_delay_msecs %u ", m->pg_init_delay_msecs); | |
c9e45581 | 1377 | } |
1da177e4 | 1378 | |
cfae5c9b | 1379 | if (!m->hw_handler_name || type == STATUSTYPE_INFO) |
1da177e4 LT |
1380 | DMEMIT("0 "); |
1381 | else | |
cfae5c9b | 1382 | DMEMIT("1 %s ", m->hw_handler_name); |
1da177e4 LT |
1383 | |
1384 | DMEMIT("%u ", m->nr_priority_groups); | |
1385 | ||
1386 | if (m->next_pg) | |
1387 | pg_num = m->next_pg->pg_num; | |
1388 | else if (m->current_pg) | |
1389 | pg_num = m->current_pg->pg_num; | |
1390 | else | |
a490a07a | 1391 | pg_num = (m->nr_priority_groups ? 1 : 0); |
1da177e4 LT |
1392 | |
1393 | DMEMIT("%u ", pg_num); | |
1394 | ||
1395 | switch (type) { | |
1396 | case STATUSTYPE_INFO: | |
1397 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1398 | if (pg->bypassed) | |
1399 | state = 'D'; /* Disabled */ | |
1400 | else if (pg == m->current_pg) | |
1401 | state = 'A'; /* Currently Active */ | |
1402 | else | |
1403 | state = 'E'; /* Enabled */ | |
1404 | ||
1405 | DMEMIT("%c ", state); | |
1406 | ||
1407 | if (pg->ps.type->status) | |
1408 | sz += pg->ps.type->status(&pg->ps, NULL, type, | |
1409 | result + sz, | |
1410 | maxlen - sz); | |
1411 | else | |
1412 | DMEMIT("0 "); | |
1413 | ||
1414 | DMEMIT("%u %u ", pg->nr_pgpaths, | |
1415 | pg->ps.type->info_args); | |
1416 | ||
1417 | list_for_each_entry(p, &pg->pgpaths, list) { | |
1418 | DMEMIT("%s %s %u ", p->path.dev->name, | |
6680073d | 1419 | p->is_active ? "A" : "F", |
1da177e4 LT |
1420 | p->fail_count); |
1421 | if (pg->ps.type->status) | |
1422 | sz += pg->ps.type->status(&pg->ps, | |
1423 | &p->path, type, result + sz, | |
1424 | maxlen - sz); | |
1425 | } | |
1426 | } | |
1427 | break; | |
1428 | ||
1429 | case STATUSTYPE_TABLE: | |
1430 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1431 | DMEMIT("%s ", pg->ps.type->name); | |
1432 | ||
1433 | if (pg->ps.type->status) | |
1434 | sz += pg->ps.type->status(&pg->ps, NULL, type, | |
1435 | result + sz, | |
1436 | maxlen - sz); | |
1437 | else | |
1438 | DMEMIT("0 "); | |
1439 | ||
1440 | DMEMIT("%u %u ", pg->nr_pgpaths, | |
1441 | pg->ps.type->table_args); | |
1442 | ||
1443 | list_for_each_entry(p, &pg->pgpaths, list) { | |
1444 | DMEMIT("%s ", p->path.dev->name); | |
1445 | if (pg->ps.type->status) | |
1446 | sz += pg->ps.type->status(&pg->ps, | |
1447 | &p->path, type, result + sz, | |
1448 | maxlen - sz); | |
1449 | } | |
1450 | } | |
1451 | break; | |
1452 | } | |
1453 | ||
1454 | spin_unlock_irqrestore(&m->lock, flags); | |
1455 | ||
1456 | return 0; | |
1457 | } | |
1458 | ||
1459 | static int multipath_message(struct dm_target *ti, unsigned argc, char **argv) | |
1460 | { | |
6380f26f | 1461 | int r = -EINVAL; |
1da177e4 LT |
1462 | struct dm_dev *dev; |
1463 | struct multipath *m = (struct multipath *) ti->private; | |
1464 | action_fn action; | |
1465 | ||
6380f26f MA |
1466 | mutex_lock(&m->work_mutex); |
1467 | ||
c2f3d24b KU |
1468 | if (dm_suspended(ti)) { |
1469 | r = -EBUSY; | |
1470 | goto out; | |
1471 | } | |
1472 | ||
1da177e4 | 1473 | if (argc == 1) { |
498f0103 | 1474 | if (!strcasecmp(argv[0], "queue_if_no_path")) { |
6380f26f MA |
1475 | r = queue_if_no_path(m, 1, 0); |
1476 | goto out; | |
498f0103 | 1477 | } else if (!strcasecmp(argv[0], "fail_if_no_path")) { |
6380f26f MA |
1478 | r = queue_if_no_path(m, 0, 0); |
1479 | goto out; | |
1480 | } | |
1da177e4 LT |
1481 | } |
1482 | ||
6380f26f MA |
1483 | if (argc != 2) { |
1484 | DMWARN("Unrecognised multipath message received."); | |
1485 | goto out; | |
1486 | } | |
1da177e4 | 1487 | |
498f0103 | 1488 | if (!strcasecmp(argv[0], "disable_group")) { |
6380f26f MA |
1489 | r = bypass_pg_num(m, argv[1], 1); |
1490 | goto out; | |
498f0103 | 1491 | } else if (!strcasecmp(argv[0], "enable_group")) { |
6380f26f MA |
1492 | r = bypass_pg_num(m, argv[1], 0); |
1493 | goto out; | |
498f0103 | 1494 | } else if (!strcasecmp(argv[0], "switch_group")) { |
6380f26f MA |
1495 | r = switch_pg_num(m, argv[1]); |
1496 | goto out; | |
498f0103 | 1497 | } else if (!strcasecmp(argv[0], "reinstate_path")) |
1da177e4 | 1498 | action = reinstate_path; |
498f0103 | 1499 | else if (!strcasecmp(argv[0], "fail_path")) |
1da177e4 | 1500 | action = fail_path; |
6380f26f MA |
1501 | else { |
1502 | DMWARN("Unrecognised multipath message received."); | |
1503 | goto out; | |
1504 | } | |
1da177e4 | 1505 | |
8215d6ec | 1506 | r = dm_get_device(ti, argv[1], dm_table_get_mode(ti->table), &dev); |
1da177e4 | 1507 | if (r) { |
72d94861 | 1508 | DMWARN("message: error getting device %s", |
1da177e4 | 1509 | argv[1]); |
6380f26f | 1510 | goto out; |
1da177e4 LT |
1511 | } |
1512 | ||
1513 | r = action_dev(m, dev, action); | |
1514 | ||
1515 | dm_put_device(ti, dev); | |
1516 | ||
6380f26f MA |
1517 | out: |
1518 | mutex_unlock(&m->work_mutex); | |
1da177e4 | 1519 | return r; |
1da177e4 LT |
1520 | } |
1521 | ||
647b3d00 | 1522 | static int multipath_ioctl(struct dm_target *ti, unsigned int cmd, |
9af4aa30 MB |
1523 | unsigned long arg) |
1524 | { | |
1525 | struct multipath *m = (struct multipath *) ti->private; | |
1526 | struct block_device *bdev = NULL; | |
633a08b8 | 1527 | fmode_t mode = 0; |
9af4aa30 MB |
1528 | unsigned long flags; |
1529 | int r = 0; | |
1530 | ||
1531 | spin_lock_irqsave(&m->lock, flags); | |
1532 | ||
1533 | if (!m->current_pgpath) | |
02ab823f | 1534 | __choose_pgpath(m, 0); |
9af4aa30 | 1535 | |
e90dae1f | 1536 | if (m->current_pgpath) { |
9af4aa30 | 1537 | bdev = m->current_pgpath->path.dev->bdev; |
633a08b8 | 1538 | mode = m->current_pgpath->path.dev->mode; |
e90dae1f | 1539 | } |
9af4aa30 MB |
1540 | |
1541 | if (m->queue_io) | |
1542 | r = -EAGAIN; | |
1543 | else if (!bdev) | |
1544 | r = -EIO; | |
1545 | ||
1546 | spin_unlock_irqrestore(&m->lock, flags); | |
1547 | ||
ec8013be PB |
1548 | /* |
1549 | * Only pass ioctls through if the device sizes match exactly. | |
1550 | */ | |
1551 | if (!r && ti->len != i_size_read(bdev->bd_inode) >> SECTOR_SHIFT) | |
1552 | r = scsi_verify_blk_ioctl(NULL, cmd); | |
1553 | ||
633a08b8 | 1554 | return r ? : __blkdev_driver_ioctl(bdev, mode, cmd, arg); |
9af4aa30 MB |
1555 | } |
1556 | ||
af4874e0 MS |
1557 | static int multipath_iterate_devices(struct dm_target *ti, |
1558 | iterate_devices_callout_fn fn, void *data) | |
1559 | { | |
1560 | struct multipath *m = ti->private; | |
1561 | struct priority_group *pg; | |
1562 | struct pgpath *p; | |
1563 | int ret = 0; | |
1564 | ||
1565 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1566 | list_for_each_entry(p, &pg->pgpaths, list) { | |
5dea271b | 1567 | ret = fn(ti, p->path.dev, ti->begin, ti->len, data); |
af4874e0 MS |
1568 | if (ret) |
1569 | goto out; | |
1570 | } | |
1571 | } | |
1572 | ||
1573 | out: | |
1574 | return ret; | |
1575 | } | |
1576 | ||
f40c67f0 KU |
1577 | static int __pgpath_busy(struct pgpath *pgpath) |
1578 | { | |
1579 | struct request_queue *q = bdev_get_queue(pgpath->path.dev->bdev); | |
1580 | ||
1581 | return dm_underlying_device_busy(q); | |
1582 | } | |
1583 | ||
1584 | /* | |
1585 | * We return "busy", only when we can map I/Os but underlying devices | |
1586 | * are busy (so even if we map I/Os now, the I/Os will wait on | |
1587 | * the underlying queue). | |
1588 | * In other words, if we want to kill I/Os or queue them inside us | |
1589 | * due to map unavailability, we don't return "busy". Otherwise, | |
1590 | * dm core won't give us the I/Os and we can't do what we want. | |
1591 | */ | |
1592 | static int multipath_busy(struct dm_target *ti) | |
1593 | { | |
1594 | int busy = 0, has_active = 0; | |
1595 | struct multipath *m = ti->private; | |
1596 | struct priority_group *pg; | |
1597 | struct pgpath *pgpath; | |
1598 | unsigned long flags; | |
1599 | ||
1600 | spin_lock_irqsave(&m->lock, flags); | |
1601 | ||
1602 | /* Guess which priority_group will be used at next mapping time */ | |
1603 | if (unlikely(!m->current_pgpath && m->next_pg)) | |
1604 | pg = m->next_pg; | |
1605 | else if (likely(m->current_pg)) | |
1606 | pg = m->current_pg; | |
1607 | else | |
1608 | /* | |
1609 | * We don't know which pg will be used at next mapping time. | |
1610 | * We don't call __choose_pgpath() here to avoid to trigger | |
1611 | * pg_init just by busy checking. | |
1612 | * So we don't know whether underlying devices we will be using | |
1613 | * at next mapping time are busy or not. Just try mapping. | |
1614 | */ | |
1615 | goto out; | |
1616 | ||
1617 | /* | |
1618 | * If there is one non-busy active path at least, the path selector | |
1619 | * will be able to select it. So we consider such a pg as not busy. | |
1620 | */ | |
1621 | busy = 1; | |
1622 | list_for_each_entry(pgpath, &pg->pgpaths, list) | |
1623 | if (pgpath->is_active) { | |
1624 | has_active = 1; | |
1625 | ||
1626 | if (!__pgpath_busy(pgpath)) { | |
1627 | busy = 0; | |
1628 | break; | |
1629 | } | |
1630 | } | |
1631 | ||
1632 | if (!has_active) | |
1633 | /* | |
1634 | * No active path in this pg, so this pg won't be used and | |
1635 | * the current_pg will be changed at next mapping time. | |
1636 | * We need to try mapping to determine it. | |
1637 | */ | |
1638 | busy = 0; | |
1639 | ||
1640 | out: | |
1641 | spin_unlock_irqrestore(&m->lock, flags); | |
1642 | ||
1643 | return busy; | |
1644 | } | |
1645 | ||
1da177e4 LT |
1646 | /*----------------------------------------------------------------- |
1647 | * Module setup | |
1648 | *---------------------------------------------------------------*/ | |
1649 | static struct target_type multipath_target = { | |
1650 | .name = "multipath", | |
19040c0b | 1651 | .version = {1, 3, 0}, |
1da177e4 LT |
1652 | .module = THIS_MODULE, |
1653 | .ctr = multipath_ctr, | |
1654 | .dtr = multipath_dtr, | |
f40c67f0 KU |
1655 | .map_rq = multipath_map, |
1656 | .rq_end_io = multipath_end_io, | |
1da177e4 | 1657 | .presuspend = multipath_presuspend, |
6df400ab | 1658 | .postsuspend = multipath_postsuspend, |
1da177e4 LT |
1659 | .resume = multipath_resume, |
1660 | .status = multipath_status, | |
1661 | .message = multipath_message, | |
9af4aa30 | 1662 | .ioctl = multipath_ioctl, |
af4874e0 | 1663 | .iterate_devices = multipath_iterate_devices, |
f40c67f0 | 1664 | .busy = multipath_busy, |
1da177e4 LT |
1665 | }; |
1666 | ||
1667 | static int __init dm_multipath_init(void) | |
1668 | { | |
1669 | int r; | |
1670 | ||
1671 | /* allocate a slab for the dm_ios */ | |
028867ac | 1672 | _mpio_cache = KMEM_CACHE(dm_mpath_io, 0); |
1da177e4 LT |
1673 | if (!_mpio_cache) |
1674 | return -ENOMEM; | |
1675 | ||
1676 | r = dm_register_target(&multipath_target); | |
1677 | if (r < 0) { | |
0cd33124 | 1678 | DMERR("register failed %d", r); |
1da177e4 LT |
1679 | kmem_cache_destroy(_mpio_cache); |
1680 | return -EINVAL; | |
1681 | } | |
1682 | ||
4d4d66ab | 1683 | kmultipathd = alloc_workqueue("kmpathd", WQ_MEM_RECLAIM, 0); |
c557308e | 1684 | if (!kmultipathd) { |
0cd33124 | 1685 | DMERR("failed to create workqueue kmpathd"); |
c557308e AK |
1686 | dm_unregister_target(&multipath_target); |
1687 | kmem_cache_destroy(_mpio_cache); | |
1688 | return -ENOMEM; | |
1689 | } | |
1690 | ||
bab7cfc7 CS |
1691 | /* |
1692 | * A separate workqueue is used to handle the device handlers | |
1693 | * to avoid overloading existing workqueue. Overloading the | |
1694 | * old workqueue would also create a bottleneck in the | |
1695 | * path of the storage hardware device activation. | |
1696 | */ | |
4d4d66ab TH |
1697 | kmpath_handlerd = alloc_ordered_workqueue("kmpath_handlerd", |
1698 | WQ_MEM_RECLAIM); | |
bab7cfc7 CS |
1699 | if (!kmpath_handlerd) { |
1700 | DMERR("failed to create workqueue kmpath_handlerd"); | |
1701 | destroy_workqueue(kmultipathd); | |
1702 | dm_unregister_target(&multipath_target); | |
1703 | kmem_cache_destroy(_mpio_cache); | |
1704 | return -ENOMEM; | |
1705 | } | |
1706 | ||
72d94861 | 1707 | DMINFO("version %u.%u.%u loaded", |
1da177e4 LT |
1708 | multipath_target.version[0], multipath_target.version[1], |
1709 | multipath_target.version[2]); | |
1710 | ||
1711 | return r; | |
1712 | } | |
1713 | ||
1714 | static void __exit dm_multipath_exit(void) | |
1715 | { | |
bab7cfc7 | 1716 | destroy_workqueue(kmpath_handlerd); |
c557308e AK |
1717 | destroy_workqueue(kmultipathd); |
1718 | ||
10d3bd09 | 1719 | dm_unregister_target(&multipath_target); |
1da177e4 LT |
1720 | kmem_cache_destroy(_mpio_cache); |
1721 | } | |
1722 | ||
1da177e4 LT |
1723 | module_init(dm_multipath_init); |
1724 | module_exit(dm_multipath_exit); | |
1725 | ||
1726 | MODULE_DESCRIPTION(DM_NAME " multipath target"); | |
1727 | MODULE_AUTHOR("Sistina Software <dm-devel@redhat.com>"); | |
1728 | MODULE_LICENSE("GPL"); |