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 | ||
f4790826 | 10 | #include "dm.h" |
1da177e4 | 11 | #include "dm-path-selector.h" |
b15546f9 | 12 | #include "dm-uevent.h" |
1da177e4 LT |
13 | |
14 | #include <linux/ctype.h> | |
15 | #include <linux/init.h> | |
16 | #include <linux/mempool.h> | |
17 | #include <linux/module.h> | |
18 | #include <linux/pagemap.h> | |
19 | #include <linux/slab.h> | |
20 | #include <linux/time.h> | |
21 | #include <linux/workqueue.h> | |
35991652 | 22 | #include <linux/delay.h> |
cfae5c9b | 23 | #include <scsi/scsi_dh.h> |
60063497 | 24 | #include <linux/atomic.h> |
1da177e4 | 25 | |
72d94861 | 26 | #define DM_MSG_PREFIX "multipath" |
4e2d19e4 CS |
27 | #define DM_PG_INIT_DELAY_MSECS 2000 |
28 | #define DM_PG_INIT_DELAY_DEFAULT ((unsigned) -1) | |
1da177e4 LT |
29 | |
30 | /* Path properties */ | |
31 | struct pgpath { | |
32 | struct list_head list; | |
33 | ||
34 | struct priority_group *pg; /* Owning PG */ | |
6680073d | 35 | unsigned is_active; /* Path status */ |
1da177e4 LT |
36 | unsigned fail_count; /* Cumulative failure count */ |
37 | ||
c922d5f7 | 38 | struct dm_path path; |
4e2d19e4 | 39 | struct delayed_work activate_path; |
1da177e4 LT |
40 | }; |
41 | ||
42 | #define path_to_pgpath(__pgp) container_of((__pgp), struct pgpath, path) | |
43 | ||
44 | /* | |
45 | * Paths are grouped into Priority Groups and numbered from 1 upwards. | |
46 | * Each has a path selector which controls which path gets used. | |
47 | */ | |
48 | struct priority_group { | |
49 | struct list_head list; | |
50 | ||
51 | struct multipath *m; /* Owning multipath instance */ | |
52 | struct path_selector ps; | |
53 | ||
54 | unsigned pg_num; /* Reference number */ | |
55 | unsigned bypassed; /* Temporarily bypass this PG? */ | |
56 | ||
57 | unsigned nr_pgpaths; /* Number of paths in PG */ | |
58 | struct list_head pgpaths; | |
59 | }; | |
60 | ||
61 | /* Multipath context */ | |
62 | struct multipath { | |
63 | struct list_head list; | |
64 | struct dm_target *ti; | |
65 | ||
cfae5c9b | 66 | const char *hw_handler_name; |
2bfd2e13 | 67 | char *hw_handler_params; |
4e2d19e4 | 68 | |
1fbdd2b3 MS |
69 | spinlock_t lock; |
70 | ||
1da177e4 LT |
71 | unsigned nr_priority_groups; |
72 | struct list_head priority_groups; | |
4e2d19e4 CS |
73 | |
74 | wait_queue_head_t pg_init_wait; /* Wait for pg_init completion */ | |
75 | ||
1da177e4 | 76 | unsigned pg_init_required; /* pg_init needs calling? */ |
c3cd4f6b | 77 | unsigned pg_init_in_progress; /* Only one pg_init allowed at once */ |
4e2d19e4 | 78 | unsigned pg_init_delay_retry; /* Delay pg_init retry? */ |
1da177e4 LT |
79 | |
80 | unsigned nr_valid_paths; /* Total number of usable paths */ | |
81 | struct pgpath *current_pgpath; | |
82 | struct priority_group *current_pg; | |
83 | struct priority_group *next_pg; /* Switch to this PG if set */ | |
84 | unsigned repeat_count; /* I/Os left before calling PS again */ | |
85 | ||
1fbdd2b3 MS |
86 | unsigned queue_io:1; /* Must we queue all I/O? */ |
87 | unsigned queue_if_no_path:1; /* Queue I/O if last path fails? */ | |
88 | unsigned saved_queue_if_no_path:1; /* Saved state during suspension */ | |
a58a935d | 89 | unsigned retain_attached_hw_handler:1; /* If there's already a hw_handler present, don't change it. */ |
954a73d5 | 90 | unsigned pg_init_disabled:1; /* pg_init is not currently allowed */ |
1fbdd2b3 | 91 | |
c9e45581 DW |
92 | unsigned pg_init_retries; /* Number of times to retry pg_init */ |
93 | unsigned pg_init_count; /* Number of times pg_init called */ | |
4e2d19e4 | 94 | unsigned pg_init_delay_msecs; /* Number of msecs before pg_init retry */ |
1da177e4 | 95 | |
1fbdd2b3 | 96 | unsigned queue_size; |
1da177e4 | 97 | struct work_struct process_queued_ios; |
f40c67f0 | 98 | struct list_head queued_ios; |
1da177e4 LT |
99 | |
100 | struct work_struct trigger_event; | |
101 | ||
102 | /* | |
028867ac | 103 | * We must use a mempool of dm_mpath_io structs so that we |
1da177e4 LT |
104 | * can resubmit bios on error. |
105 | */ | |
106 | mempool_t *mpio_pool; | |
6380f26f MA |
107 | |
108 | struct mutex work_mutex; | |
1da177e4 LT |
109 | }; |
110 | ||
111 | /* | |
112 | * Context information attached to each bio we process. | |
113 | */ | |
028867ac | 114 | struct dm_mpath_io { |
1da177e4 | 115 | struct pgpath *pgpath; |
02ab823f | 116 | size_t nr_bytes; |
1da177e4 LT |
117 | }; |
118 | ||
119 | typedef int (*action_fn) (struct pgpath *pgpath); | |
120 | ||
e18b890b | 121 | static struct kmem_cache *_mpio_cache; |
1da177e4 | 122 | |
bab7cfc7 | 123 | static struct workqueue_struct *kmultipathd, *kmpath_handlerd; |
c4028958 DH |
124 | static void process_queued_ios(struct work_struct *work); |
125 | static void trigger_event(struct work_struct *work); | |
bab7cfc7 | 126 | static void activate_path(struct work_struct *work); |
1da177e4 LT |
127 | |
128 | ||
129 | /*----------------------------------------------- | |
130 | * Allocation routines | |
131 | *-----------------------------------------------*/ | |
132 | ||
133 | static struct pgpath *alloc_pgpath(void) | |
134 | { | |
e69fae56 | 135 | struct pgpath *pgpath = kzalloc(sizeof(*pgpath), GFP_KERNEL); |
1da177e4 | 136 | |
224cb3e9 | 137 | if (pgpath) { |
6680073d | 138 | pgpath->is_active = 1; |
4e2d19e4 | 139 | INIT_DELAYED_WORK(&pgpath->activate_path, activate_path); |
224cb3e9 | 140 | } |
1da177e4 LT |
141 | |
142 | return pgpath; | |
143 | } | |
144 | ||
028867ac | 145 | static void free_pgpath(struct pgpath *pgpath) |
1da177e4 LT |
146 | { |
147 | kfree(pgpath); | |
148 | } | |
149 | ||
150 | static struct priority_group *alloc_priority_group(void) | |
151 | { | |
152 | struct priority_group *pg; | |
153 | ||
e69fae56 | 154 | pg = kzalloc(sizeof(*pg), GFP_KERNEL); |
1da177e4 | 155 | |
e69fae56 MM |
156 | if (pg) |
157 | INIT_LIST_HEAD(&pg->pgpaths); | |
1da177e4 LT |
158 | |
159 | return pg; | |
160 | } | |
161 | ||
162 | static void free_pgpaths(struct list_head *pgpaths, struct dm_target *ti) | |
163 | { | |
164 | struct pgpath *pgpath, *tmp; | |
ae11b1b3 | 165 | struct multipath *m = ti->private; |
1da177e4 LT |
166 | |
167 | list_for_each_entry_safe(pgpath, tmp, pgpaths, list) { | |
168 | list_del(&pgpath->list); | |
ae11b1b3 HR |
169 | if (m->hw_handler_name) |
170 | scsi_dh_detach(bdev_get_queue(pgpath->path.dev->bdev)); | |
1da177e4 LT |
171 | dm_put_device(ti, pgpath->path.dev); |
172 | free_pgpath(pgpath); | |
173 | } | |
174 | } | |
175 | ||
176 | static void free_priority_group(struct priority_group *pg, | |
177 | struct dm_target *ti) | |
178 | { | |
179 | struct path_selector *ps = &pg->ps; | |
180 | ||
181 | if (ps->type) { | |
182 | ps->type->destroy(ps); | |
183 | dm_put_path_selector(ps->type); | |
184 | } | |
185 | ||
186 | free_pgpaths(&pg->pgpaths, ti); | |
187 | kfree(pg); | |
188 | } | |
189 | ||
28f16c20 | 190 | static struct multipath *alloc_multipath(struct dm_target *ti) |
1da177e4 LT |
191 | { |
192 | struct multipath *m; | |
f4790826 | 193 | unsigned min_ios = dm_get_reserved_rq_based_ios(); |
1da177e4 | 194 | |
e69fae56 | 195 | m = kzalloc(sizeof(*m), GFP_KERNEL); |
1da177e4 | 196 | if (m) { |
1da177e4 | 197 | INIT_LIST_HEAD(&m->priority_groups); |
f40c67f0 | 198 | INIT_LIST_HEAD(&m->queued_ios); |
1da177e4 LT |
199 | spin_lock_init(&m->lock); |
200 | m->queue_io = 1; | |
4e2d19e4 | 201 | m->pg_init_delay_msecs = DM_PG_INIT_DELAY_DEFAULT; |
c4028958 DH |
202 | INIT_WORK(&m->process_queued_ios, process_queued_ios); |
203 | INIT_WORK(&m->trigger_event, trigger_event); | |
2bded7bd | 204 | init_waitqueue_head(&m->pg_init_wait); |
6380f26f | 205 | mutex_init(&m->work_mutex); |
f4790826 | 206 | m->mpio_pool = mempool_create_slab_pool(min_ios, _mpio_cache); |
1da177e4 LT |
207 | if (!m->mpio_pool) { |
208 | kfree(m); | |
209 | return NULL; | |
210 | } | |
28f16c20 MM |
211 | m->ti = ti; |
212 | ti->private = m; | |
1da177e4 LT |
213 | } |
214 | ||
215 | return m; | |
216 | } | |
217 | ||
218 | static void free_multipath(struct multipath *m) | |
219 | { | |
220 | struct priority_group *pg, *tmp; | |
1da177e4 LT |
221 | |
222 | list_for_each_entry_safe(pg, tmp, &m->priority_groups, list) { | |
223 | list_del(&pg->list); | |
224 | free_priority_group(pg, m->ti); | |
225 | } | |
226 | ||
cfae5c9b | 227 | kfree(m->hw_handler_name); |
2bfd2e13 | 228 | kfree(m->hw_handler_params); |
1da177e4 LT |
229 | mempool_destroy(m->mpio_pool); |
230 | kfree(m); | |
231 | } | |
232 | ||
466891f9 JN |
233 | static int set_mapinfo(struct multipath *m, union map_info *info) |
234 | { | |
235 | struct dm_mpath_io *mpio; | |
236 | ||
237 | mpio = mempool_alloc(m->mpio_pool, GFP_ATOMIC); | |
238 | if (!mpio) | |
239 | return -ENOMEM; | |
240 | ||
241 | memset(mpio, 0, sizeof(*mpio)); | |
242 | info->ptr = mpio; | |
243 | ||
244 | return 0; | |
245 | } | |
246 | ||
247 | static void clear_mapinfo(struct multipath *m, union map_info *info) | |
248 | { | |
249 | struct dm_mpath_io *mpio = info->ptr; | |
250 | ||
251 | info->ptr = NULL; | |
252 | mempool_free(mpio, m->mpio_pool); | |
253 | } | |
1da177e4 LT |
254 | |
255 | /*----------------------------------------------- | |
256 | * Path selection | |
257 | *-----------------------------------------------*/ | |
258 | ||
fb612642 KU |
259 | static void __pg_init_all_paths(struct multipath *m) |
260 | { | |
261 | struct pgpath *pgpath; | |
4e2d19e4 | 262 | unsigned long pg_init_delay = 0; |
fb612642 KU |
263 | |
264 | m->pg_init_count++; | |
265 | m->pg_init_required = 0; | |
4e2d19e4 CS |
266 | if (m->pg_init_delay_retry) |
267 | pg_init_delay = msecs_to_jiffies(m->pg_init_delay_msecs != DM_PG_INIT_DELAY_DEFAULT ? | |
268 | m->pg_init_delay_msecs : DM_PG_INIT_DELAY_MSECS); | |
fb612642 KU |
269 | list_for_each_entry(pgpath, &m->current_pg->pgpaths, list) { |
270 | /* Skip failed paths */ | |
271 | if (!pgpath->is_active) | |
272 | continue; | |
4e2d19e4 CS |
273 | if (queue_delayed_work(kmpath_handlerd, &pgpath->activate_path, |
274 | pg_init_delay)) | |
fb612642 KU |
275 | m->pg_init_in_progress++; |
276 | } | |
277 | } | |
278 | ||
1da177e4 LT |
279 | static void __switch_pg(struct multipath *m, struct pgpath *pgpath) |
280 | { | |
1da177e4 LT |
281 | m->current_pg = pgpath->pg; |
282 | ||
283 | /* Must we initialise the PG first, and queue I/O till it's ready? */ | |
cfae5c9b | 284 | if (m->hw_handler_name) { |
1da177e4 LT |
285 | m->pg_init_required = 1; |
286 | m->queue_io = 1; | |
287 | } else { | |
288 | m->pg_init_required = 0; | |
289 | m->queue_io = 0; | |
290 | } | |
c9e45581 DW |
291 | |
292 | m->pg_init_count = 0; | |
1da177e4 LT |
293 | } |
294 | ||
02ab823f KU |
295 | static int __choose_path_in_pg(struct multipath *m, struct priority_group *pg, |
296 | size_t nr_bytes) | |
1da177e4 | 297 | { |
c922d5f7 | 298 | struct dm_path *path; |
1da177e4 | 299 | |
02ab823f | 300 | path = pg->ps.type->select_path(&pg->ps, &m->repeat_count, nr_bytes); |
1da177e4 LT |
301 | if (!path) |
302 | return -ENXIO; | |
303 | ||
304 | m->current_pgpath = path_to_pgpath(path); | |
305 | ||
306 | if (m->current_pg != pg) | |
307 | __switch_pg(m, m->current_pgpath); | |
308 | ||
309 | return 0; | |
310 | } | |
311 | ||
02ab823f | 312 | static void __choose_pgpath(struct multipath *m, size_t nr_bytes) |
1da177e4 LT |
313 | { |
314 | struct priority_group *pg; | |
315 | unsigned bypassed = 1; | |
316 | ||
317 | if (!m->nr_valid_paths) | |
318 | goto failed; | |
319 | ||
320 | /* Were we instructed to switch PG? */ | |
321 | if (m->next_pg) { | |
322 | pg = m->next_pg; | |
323 | m->next_pg = NULL; | |
02ab823f | 324 | if (!__choose_path_in_pg(m, pg, nr_bytes)) |
1da177e4 LT |
325 | return; |
326 | } | |
327 | ||
328 | /* Don't change PG until it has no remaining paths */ | |
02ab823f | 329 | if (m->current_pg && !__choose_path_in_pg(m, m->current_pg, nr_bytes)) |
1da177e4 LT |
330 | return; |
331 | ||
332 | /* | |
333 | * Loop through priority groups until we find a valid path. | |
334 | * First time we skip PGs marked 'bypassed'. | |
f220fd4e MC |
335 | * Second time we only try the ones we skipped, but set |
336 | * pg_init_delay_retry so we do not hammer controllers. | |
1da177e4 LT |
337 | */ |
338 | do { | |
339 | list_for_each_entry(pg, &m->priority_groups, list) { | |
340 | if (pg->bypassed == bypassed) | |
341 | continue; | |
f220fd4e MC |
342 | if (!__choose_path_in_pg(m, pg, nr_bytes)) { |
343 | if (!bypassed) | |
344 | m->pg_init_delay_retry = 1; | |
1da177e4 | 345 | return; |
f220fd4e | 346 | } |
1da177e4 LT |
347 | } |
348 | } while (bypassed--); | |
349 | ||
350 | failed: | |
351 | m->current_pgpath = NULL; | |
352 | m->current_pg = NULL; | |
353 | } | |
354 | ||
45e15720 KU |
355 | /* |
356 | * Check whether bios must be queued in the device-mapper core rather | |
357 | * than here in the target. | |
358 | * | |
359 | * m->lock must be held on entry. | |
360 | * | |
361 | * If m->queue_if_no_path and m->saved_queue_if_no_path hold the | |
362 | * same value then we are not between multipath_presuspend() | |
363 | * and multipath_resume() calls and we have no need to check | |
364 | * for the DMF_NOFLUSH_SUSPENDING flag. | |
365 | */ | |
366 | static int __must_push_back(struct multipath *m) | |
367 | { | |
368 | return (m->queue_if_no_path != m->saved_queue_if_no_path && | |
369 | dm_noflush_suspending(m->ti)); | |
370 | } | |
371 | ||
f40c67f0 | 372 | static int map_io(struct multipath *m, struct request *clone, |
466891f9 | 373 | union map_info *map_context, unsigned was_queued) |
1da177e4 | 374 | { |
d2a7ad29 | 375 | int r = DM_MAPIO_REMAPPED; |
f40c67f0 | 376 | size_t nr_bytes = blk_rq_bytes(clone); |
1da177e4 LT |
377 | unsigned long flags; |
378 | struct pgpath *pgpath; | |
f40c67f0 | 379 | struct block_device *bdev; |
466891f9 | 380 | struct dm_mpath_io *mpio = map_context->ptr; |
1da177e4 LT |
381 | |
382 | spin_lock_irqsave(&m->lock, flags); | |
383 | ||
384 | /* Do we need to select a new pgpath? */ | |
385 | if (!m->current_pgpath || | |
386 | (!m->queue_io && (m->repeat_count && --m->repeat_count == 0))) | |
02ab823f | 387 | __choose_pgpath(m, nr_bytes); |
1da177e4 LT |
388 | |
389 | pgpath = m->current_pgpath; | |
390 | ||
391 | if (was_queued) | |
392 | m->queue_size--; | |
393 | ||
b63349a7 HR |
394 | if (m->pg_init_required) { |
395 | if (!m->pg_init_in_progress) | |
396 | queue_work(kmultipathd, &m->process_queued_ios); | |
397 | r = DM_MAPIO_REQUEUE; | |
398 | } else if ((pgpath && m->queue_io) || | |
399 | (!pgpath && m->queue_if_no_path)) { | |
1da177e4 | 400 | /* Queue for the daemon to resubmit */ |
f40c67f0 | 401 | list_add_tail(&clone->queuelist, &m->queued_ios); |
1da177e4 | 402 | m->queue_size++; |
b63349a7 | 403 | if (!m->queue_io) |
c557308e | 404 | queue_work(kmultipathd, &m->process_queued_ios); |
1da177e4 | 405 | pgpath = NULL; |
d2a7ad29 | 406 | r = DM_MAPIO_SUBMITTED; |
f40c67f0 KU |
407 | } else if (pgpath) { |
408 | bdev = pgpath->path.dev->bdev; | |
409 | clone->q = bdev_get_queue(bdev); | |
410 | clone->rq_disk = bdev->bd_disk; | |
411 | } else if (__must_push_back(m)) | |
45e15720 KU |
412 | r = DM_MAPIO_REQUEUE; |
413 | else | |
414 | r = -EIO; /* Failed */ | |
1da177e4 LT |
415 | |
416 | mpio->pgpath = pgpath; | |
02ab823f KU |
417 | mpio->nr_bytes = nr_bytes; |
418 | ||
419 | if (r == DM_MAPIO_REMAPPED && pgpath->pg->ps.type->start_io) | |
420 | pgpath->pg->ps.type->start_io(&pgpath->pg->ps, &pgpath->path, | |
421 | nr_bytes); | |
1da177e4 LT |
422 | |
423 | spin_unlock_irqrestore(&m->lock, flags); | |
424 | ||
425 | return r; | |
426 | } | |
427 | ||
428 | /* | |
429 | * If we run out of usable paths, should we queue I/O or error it? | |
430 | */ | |
485ef69e AK |
431 | static int queue_if_no_path(struct multipath *m, unsigned queue_if_no_path, |
432 | unsigned save_old_value) | |
1da177e4 LT |
433 | { |
434 | unsigned long flags; | |
435 | ||
436 | spin_lock_irqsave(&m->lock, flags); | |
437 | ||
485ef69e AK |
438 | if (save_old_value) |
439 | m->saved_queue_if_no_path = m->queue_if_no_path; | |
440 | else | |
441 | m->saved_queue_if_no_path = queue_if_no_path; | |
1da177e4 | 442 | m->queue_if_no_path = queue_if_no_path; |
c3cd4f6b | 443 | if (!m->queue_if_no_path && m->queue_size) |
c557308e | 444 | queue_work(kmultipathd, &m->process_queued_ios); |
1da177e4 LT |
445 | |
446 | spin_unlock_irqrestore(&m->lock, flags); | |
447 | ||
448 | return 0; | |
449 | } | |
450 | ||
451 | /*----------------------------------------------------------------- | |
452 | * The multipath daemon is responsible for resubmitting queued ios. | |
453 | *---------------------------------------------------------------*/ | |
454 | ||
455 | static void dispatch_queued_ios(struct multipath *m) | |
456 | { | |
457 | int r; | |
458 | unsigned long flags; | |
1da177e4 | 459 | union map_info *info; |
f40c67f0 KU |
460 | struct request *clone, *n; |
461 | LIST_HEAD(cl); | |
1da177e4 LT |
462 | |
463 | spin_lock_irqsave(&m->lock, flags); | |
f40c67f0 | 464 | list_splice_init(&m->queued_ios, &cl); |
1da177e4 LT |
465 | spin_unlock_irqrestore(&m->lock, flags); |
466 | ||
f40c67f0 KU |
467 | list_for_each_entry_safe(clone, n, &cl, queuelist) { |
468 | list_del_init(&clone->queuelist); | |
1da177e4 | 469 | |
f40c67f0 | 470 | info = dm_get_rq_mapinfo(clone); |
1da177e4 | 471 | |
466891f9 | 472 | r = map_io(m, clone, info, 1); |
f40c67f0 | 473 | if (r < 0) { |
466891f9 | 474 | clear_mapinfo(m, info); |
f40c67f0 KU |
475 | dm_kill_unmapped_request(clone, r); |
476 | } else if (r == DM_MAPIO_REMAPPED) | |
477 | dm_dispatch_request(clone); | |
478 | else if (r == DM_MAPIO_REQUEUE) { | |
466891f9 | 479 | clear_mapinfo(m, info); |
f40c67f0 KU |
480 | dm_requeue_unmapped_request(clone); |
481 | } | |
1da177e4 LT |
482 | } |
483 | } | |
484 | ||
c4028958 | 485 | static void process_queued_ios(struct work_struct *work) |
1da177e4 | 486 | { |
c4028958 DH |
487 | struct multipath *m = |
488 | container_of(work, struct multipath, process_queued_ios); | |
fb612642 | 489 | struct pgpath *pgpath = NULL; |
e54f77dd | 490 | unsigned must_queue = 1; |
1da177e4 LT |
491 | unsigned long flags; |
492 | ||
493 | spin_lock_irqsave(&m->lock, flags); | |
494 | ||
495 | if (!m->current_pgpath) | |
02ab823f | 496 | __choose_pgpath(m, 0); |
1da177e4 LT |
497 | |
498 | pgpath = m->current_pgpath; | |
499 | ||
c3cd4f6b AK |
500 | if ((pgpath && !m->queue_io) || |
501 | (!pgpath && !m->queue_if_no_path)) | |
502 | must_queue = 0; | |
1da177e4 | 503 | |
954a73d5 SKM |
504 | if (m->pg_init_required && !m->pg_init_in_progress && pgpath && |
505 | !m->pg_init_disabled) | |
fb612642 KU |
506 | __pg_init_all_paths(m); |
507 | ||
1da177e4 | 508 | spin_unlock_irqrestore(&m->lock, flags); |
1da177e4 LT |
509 | if (!must_queue) |
510 | dispatch_queued_ios(m); | |
511 | } | |
512 | ||
513 | /* | |
514 | * An event is triggered whenever a path is taken out of use. | |
515 | * Includes path failure and PG bypass. | |
516 | */ | |
c4028958 | 517 | static void trigger_event(struct work_struct *work) |
1da177e4 | 518 | { |
c4028958 DH |
519 | struct multipath *m = |
520 | container_of(work, struct multipath, trigger_event); | |
1da177e4 LT |
521 | |
522 | dm_table_event(m->ti->table); | |
523 | } | |
524 | ||
525 | /*----------------------------------------------------------------- | |
526 | * Constructor/argument parsing: | |
527 | * <#multipath feature args> [<arg>]* | |
528 | * <#hw_handler args> [hw_handler [<arg>]*] | |
529 | * <#priority groups> | |
530 | * <initial priority group> | |
531 | * [<selector> <#selector args> [<arg>]* | |
532 | * <#paths> <#per-path selector args> | |
533 | * [<path> [<arg>]* ]+ ]+ | |
534 | *---------------------------------------------------------------*/ | |
498f0103 | 535 | static int parse_path_selector(struct dm_arg_set *as, struct priority_group *pg, |
1da177e4 LT |
536 | struct dm_target *ti) |
537 | { | |
538 | int r; | |
539 | struct path_selector_type *pst; | |
540 | unsigned ps_argc; | |
541 | ||
498f0103 | 542 | static struct dm_arg _args[] = { |
72d94861 | 543 | {0, 1024, "invalid number of path selector args"}, |
1da177e4 LT |
544 | }; |
545 | ||
498f0103 | 546 | pst = dm_get_path_selector(dm_shift_arg(as)); |
1da177e4 | 547 | if (!pst) { |
72d94861 | 548 | ti->error = "unknown path selector type"; |
1da177e4 LT |
549 | return -EINVAL; |
550 | } | |
551 | ||
498f0103 | 552 | r = dm_read_arg_group(_args, as, &ps_argc, &ti->error); |
371b2e34 MP |
553 | if (r) { |
554 | dm_put_path_selector(pst); | |
1da177e4 | 555 | return -EINVAL; |
371b2e34 | 556 | } |
1da177e4 LT |
557 | |
558 | r = pst->create(&pg->ps, ps_argc, as->argv); | |
559 | if (r) { | |
560 | dm_put_path_selector(pst); | |
72d94861 | 561 | ti->error = "path selector constructor failed"; |
1da177e4 LT |
562 | return r; |
563 | } | |
564 | ||
565 | pg->ps.type = pst; | |
498f0103 | 566 | dm_consume_args(as, ps_argc); |
1da177e4 LT |
567 | |
568 | return 0; | |
569 | } | |
570 | ||
498f0103 | 571 | static struct pgpath *parse_path(struct dm_arg_set *as, struct path_selector *ps, |
1da177e4 LT |
572 | struct dm_target *ti) |
573 | { | |
574 | int r; | |
575 | struct pgpath *p; | |
ae11b1b3 | 576 | struct multipath *m = ti->private; |
a58a935d MS |
577 | struct request_queue *q = NULL; |
578 | const char *attached_handler_name; | |
1da177e4 LT |
579 | |
580 | /* we need at least a path arg */ | |
581 | if (as->argc < 1) { | |
72d94861 | 582 | ti->error = "no device given"; |
01460f35 | 583 | return ERR_PTR(-EINVAL); |
1da177e4 LT |
584 | } |
585 | ||
586 | p = alloc_pgpath(); | |
587 | if (!p) | |
01460f35 | 588 | return ERR_PTR(-ENOMEM); |
1da177e4 | 589 | |
498f0103 | 590 | r = dm_get_device(ti, dm_shift_arg(as), dm_table_get_mode(ti->table), |
8215d6ec | 591 | &p->path.dev); |
1da177e4 | 592 | if (r) { |
72d94861 | 593 | ti->error = "error getting device"; |
1da177e4 LT |
594 | goto bad; |
595 | } | |
596 | ||
a58a935d MS |
597 | if (m->retain_attached_hw_handler || m->hw_handler_name) |
598 | q = bdev_get_queue(p->path.dev->bdev); | |
599 | ||
600 | if (m->retain_attached_hw_handler) { | |
601 | attached_handler_name = scsi_dh_attached_handler_name(q, GFP_KERNEL); | |
602 | if (attached_handler_name) { | |
603 | /* | |
604 | * Reset hw_handler_name to match the attached handler | |
605 | * and clear any hw_handler_params associated with the | |
606 | * ignored handler. | |
607 | * | |
608 | * NB. This modifies the table line to show the actual | |
609 | * handler instead of the original table passed in. | |
610 | */ | |
611 | kfree(m->hw_handler_name); | |
612 | m->hw_handler_name = attached_handler_name; | |
613 | ||
614 | kfree(m->hw_handler_params); | |
615 | m->hw_handler_params = NULL; | |
616 | } | |
617 | } | |
a0cf7ea9 | 618 | |
a58a935d MS |
619 | if (m->hw_handler_name) { |
620 | /* | |
621 | * Increments scsi_dh reference, even when using an | |
622 | * already-attached handler. | |
623 | */ | |
a0cf7ea9 HR |
624 | r = scsi_dh_attach(q, m->hw_handler_name); |
625 | if (r == -EBUSY) { | |
626 | /* | |
a58a935d | 627 | * Already attached to different hw_handler: |
a0cf7ea9 HR |
628 | * try to reattach with correct one. |
629 | */ | |
630 | scsi_dh_detach(q); | |
631 | r = scsi_dh_attach(q, m->hw_handler_name); | |
632 | } | |
633 | ||
ae11b1b3 | 634 | if (r < 0) { |
a0cf7ea9 | 635 | ti->error = "error attaching hardware handler"; |
ae11b1b3 HR |
636 | dm_put_device(ti, p->path.dev); |
637 | goto bad; | |
638 | } | |
2bfd2e13 CS |
639 | |
640 | if (m->hw_handler_params) { | |
641 | r = scsi_dh_set_params(q, m->hw_handler_params); | |
642 | if (r < 0) { | |
643 | ti->error = "unable to set hardware " | |
644 | "handler parameters"; | |
645 | scsi_dh_detach(q); | |
646 | dm_put_device(ti, p->path.dev); | |
647 | goto bad; | |
648 | } | |
649 | } | |
ae11b1b3 HR |
650 | } |
651 | ||
1da177e4 LT |
652 | r = ps->type->add_path(ps, &p->path, as->argc, as->argv, &ti->error); |
653 | if (r) { | |
654 | dm_put_device(ti, p->path.dev); | |
655 | goto bad; | |
656 | } | |
657 | ||
658 | return p; | |
659 | ||
660 | bad: | |
661 | free_pgpath(p); | |
01460f35 | 662 | return ERR_PTR(r); |
1da177e4 LT |
663 | } |
664 | ||
498f0103 | 665 | static struct priority_group *parse_priority_group(struct dm_arg_set *as, |
28f16c20 | 666 | struct multipath *m) |
1da177e4 | 667 | { |
498f0103 | 668 | static struct dm_arg _args[] = { |
72d94861 AK |
669 | {1, 1024, "invalid number of paths"}, |
670 | {0, 1024, "invalid number of selector args"} | |
1da177e4 LT |
671 | }; |
672 | ||
673 | int r; | |
498f0103 | 674 | unsigned i, nr_selector_args, nr_args; |
1da177e4 | 675 | struct priority_group *pg; |
28f16c20 | 676 | struct dm_target *ti = m->ti; |
1da177e4 LT |
677 | |
678 | if (as->argc < 2) { | |
679 | as->argc = 0; | |
01460f35 BM |
680 | ti->error = "not enough priority group arguments"; |
681 | return ERR_PTR(-EINVAL); | |
1da177e4 LT |
682 | } |
683 | ||
684 | pg = alloc_priority_group(); | |
685 | if (!pg) { | |
72d94861 | 686 | ti->error = "couldn't allocate priority group"; |
01460f35 | 687 | return ERR_PTR(-ENOMEM); |
1da177e4 LT |
688 | } |
689 | pg->m = m; | |
690 | ||
691 | r = parse_path_selector(as, pg, ti); | |
692 | if (r) | |
693 | goto bad; | |
694 | ||
695 | /* | |
696 | * read the paths | |
697 | */ | |
498f0103 | 698 | r = dm_read_arg(_args, as, &pg->nr_pgpaths, &ti->error); |
1da177e4 LT |
699 | if (r) |
700 | goto bad; | |
701 | ||
498f0103 | 702 | r = dm_read_arg(_args + 1, as, &nr_selector_args, &ti->error); |
1da177e4 LT |
703 | if (r) |
704 | goto bad; | |
705 | ||
498f0103 | 706 | nr_args = 1 + nr_selector_args; |
1da177e4 LT |
707 | for (i = 0; i < pg->nr_pgpaths; i++) { |
708 | struct pgpath *pgpath; | |
498f0103 | 709 | struct dm_arg_set path_args; |
1da177e4 | 710 | |
498f0103 | 711 | if (as->argc < nr_args) { |
148acff6 | 712 | ti->error = "not enough path parameters"; |
6bbf79a1 | 713 | r = -EINVAL; |
1da177e4 | 714 | goto bad; |
148acff6 | 715 | } |
1da177e4 | 716 | |
498f0103 | 717 | path_args.argc = nr_args; |
1da177e4 LT |
718 | path_args.argv = as->argv; |
719 | ||
720 | pgpath = parse_path(&path_args, &pg->ps, ti); | |
01460f35 BM |
721 | if (IS_ERR(pgpath)) { |
722 | r = PTR_ERR(pgpath); | |
1da177e4 | 723 | goto bad; |
01460f35 | 724 | } |
1da177e4 LT |
725 | |
726 | pgpath->pg = pg; | |
727 | list_add_tail(&pgpath->list, &pg->pgpaths); | |
498f0103 | 728 | dm_consume_args(as, nr_args); |
1da177e4 LT |
729 | } |
730 | ||
731 | return pg; | |
732 | ||
733 | bad: | |
734 | free_priority_group(pg, ti); | |
01460f35 | 735 | return ERR_PTR(r); |
1da177e4 LT |
736 | } |
737 | ||
498f0103 | 738 | static int parse_hw_handler(struct dm_arg_set *as, struct multipath *m) |
1da177e4 | 739 | { |
1da177e4 | 740 | unsigned hw_argc; |
2bfd2e13 | 741 | int ret; |
28f16c20 | 742 | struct dm_target *ti = m->ti; |
1da177e4 | 743 | |
498f0103 | 744 | static struct dm_arg _args[] = { |
72d94861 | 745 | {0, 1024, "invalid number of hardware handler args"}, |
1da177e4 LT |
746 | }; |
747 | ||
498f0103 | 748 | if (dm_read_arg_group(_args, as, &hw_argc, &ti->error)) |
1da177e4 LT |
749 | return -EINVAL; |
750 | ||
751 | if (!hw_argc) | |
752 | return 0; | |
753 | ||
498f0103 | 754 | m->hw_handler_name = kstrdup(dm_shift_arg(as), GFP_KERNEL); |
510193a2 MS |
755 | if (!try_then_request_module(scsi_dh_handler_exist(m->hw_handler_name), |
756 | "scsi_dh_%s", m->hw_handler_name)) { | |
72d94861 | 757 | ti->error = "unknown hardware handler type"; |
2bfd2e13 CS |
758 | ret = -EINVAL; |
759 | goto fail; | |
1da177e4 | 760 | } |
14e98c5c | 761 | |
2bfd2e13 CS |
762 | if (hw_argc > 1) { |
763 | char *p; | |
764 | int i, j, len = 4; | |
765 | ||
766 | for (i = 0; i <= hw_argc - 2; i++) | |
767 | len += strlen(as->argv[i]) + 1; | |
768 | p = m->hw_handler_params = kzalloc(len, GFP_KERNEL); | |
769 | if (!p) { | |
770 | ti->error = "memory allocation failed"; | |
771 | ret = -ENOMEM; | |
772 | goto fail; | |
773 | } | |
774 | j = sprintf(p, "%d", hw_argc - 1); | |
775 | for (i = 0, p+=j+1; i <= hw_argc - 2; i++, p+=j+1) | |
776 | j = sprintf(p, "%s", as->argv[i]); | |
777 | } | |
498f0103 | 778 | dm_consume_args(as, hw_argc - 1); |
1da177e4 LT |
779 | |
780 | return 0; | |
2bfd2e13 CS |
781 | fail: |
782 | kfree(m->hw_handler_name); | |
783 | m->hw_handler_name = NULL; | |
784 | return ret; | |
1da177e4 LT |
785 | } |
786 | ||
498f0103 | 787 | static int parse_features(struct dm_arg_set *as, struct multipath *m) |
1da177e4 LT |
788 | { |
789 | int r; | |
790 | unsigned argc; | |
28f16c20 | 791 | struct dm_target *ti = m->ti; |
498f0103 | 792 | const char *arg_name; |
1da177e4 | 793 | |
498f0103 | 794 | static struct dm_arg _args[] = { |
a58a935d | 795 | {0, 6, "invalid number of feature args"}, |
c9e45581 | 796 | {1, 50, "pg_init_retries must be between 1 and 50"}, |
4e2d19e4 | 797 | {0, 60000, "pg_init_delay_msecs must be between 0 and 60000"}, |
1da177e4 LT |
798 | }; |
799 | ||
498f0103 | 800 | r = dm_read_arg_group(_args, as, &argc, &ti->error); |
1da177e4 LT |
801 | if (r) |
802 | return -EINVAL; | |
803 | ||
804 | if (!argc) | |
805 | return 0; | |
806 | ||
c9e45581 | 807 | do { |
498f0103 | 808 | arg_name = dm_shift_arg(as); |
c9e45581 DW |
809 | argc--; |
810 | ||
498f0103 | 811 | if (!strcasecmp(arg_name, "queue_if_no_path")) { |
c9e45581 DW |
812 | r = queue_if_no_path(m, 1, 0); |
813 | continue; | |
814 | } | |
815 | ||
a58a935d MS |
816 | if (!strcasecmp(arg_name, "retain_attached_hw_handler")) { |
817 | m->retain_attached_hw_handler = 1; | |
818 | continue; | |
819 | } | |
820 | ||
498f0103 | 821 | if (!strcasecmp(arg_name, "pg_init_retries") && |
c9e45581 | 822 | (argc >= 1)) { |
498f0103 | 823 | r = dm_read_arg(_args + 1, as, &m->pg_init_retries, &ti->error); |
c9e45581 DW |
824 | argc--; |
825 | continue; | |
826 | } | |
827 | ||
498f0103 | 828 | if (!strcasecmp(arg_name, "pg_init_delay_msecs") && |
4e2d19e4 | 829 | (argc >= 1)) { |
498f0103 | 830 | r = dm_read_arg(_args + 2, as, &m->pg_init_delay_msecs, &ti->error); |
4e2d19e4 CS |
831 | argc--; |
832 | continue; | |
833 | } | |
834 | ||
1da177e4 | 835 | ti->error = "Unrecognised multipath feature request"; |
c9e45581 DW |
836 | r = -EINVAL; |
837 | } while (argc && !r); | |
838 | ||
839 | return r; | |
1da177e4 LT |
840 | } |
841 | ||
842 | static int multipath_ctr(struct dm_target *ti, unsigned int argc, | |
843 | char **argv) | |
844 | { | |
498f0103 MS |
845 | /* target arguments */ |
846 | static struct dm_arg _args[] = { | |
a490a07a MS |
847 | {0, 1024, "invalid number of priority groups"}, |
848 | {0, 1024, "invalid initial priority group number"}, | |
1da177e4 LT |
849 | }; |
850 | ||
851 | int r; | |
852 | struct multipath *m; | |
498f0103 | 853 | struct dm_arg_set as; |
1da177e4 LT |
854 | unsigned pg_count = 0; |
855 | unsigned next_pg_num; | |
856 | ||
857 | as.argc = argc; | |
858 | as.argv = argv; | |
859 | ||
28f16c20 | 860 | m = alloc_multipath(ti); |
1da177e4 | 861 | if (!m) { |
72d94861 | 862 | ti->error = "can't allocate multipath"; |
1da177e4 LT |
863 | return -EINVAL; |
864 | } | |
865 | ||
28f16c20 | 866 | r = parse_features(&as, m); |
1da177e4 LT |
867 | if (r) |
868 | goto bad; | |
869 | ||
28f16c20 | 870 | r = parse_hw_handler(&as, m); |
1da177e4 LT |
871 | if (r) |
872 | goto bad; | |
873 | ||
498f0103 | 874 | r = dm_read_arg(_args, &as, &m->nr_priority_groups, &ti->error); |
1da177e4 LT |
875 | if (r) |
876 | goto bad; | |
877 | ||
498f0103 | 878 | r = dm_read_arg(_args + 1, &as, &next_pg_num, &ti->error); |
1da177e4 LT |
879 | if (r) |
880 | goto bad; | |
881 | ||
a490a07a MS |
882 | if ((!m->nr_priority_groups && next_pg_num) || |
883 | (m->nr_priority_groups && !next_pg_num)) { | |
884 | ti->error = "invalid initial priority group"; | |
885 | r = -EINVAL; | |
886 | goto bad; | |
887 | } | |
888 | ||
1da177e4 LT |
889 | /* parse the priority groups */ |
890 | while (as.argc) { | |
891 | struct priority_group *pg; | |
892 | ||
28f16c20 | 893 | pg = parse_priority_group(&as, m); |
01460f35 BM |
894 | if (IS_ERR(pg)) { |
895 | r = PTR_ERR(pg); | |
1da177e4 LT |
896 | goto bad; |
897 | } | |
898 | ||
899 | m->nr_valid_paths += pg->nr_pgpaths; | |
900 | list_add_tail(&pg->list, &m->priority_groups); | |
901 | pg_count++; | |
902 | pg->pg_num = pg_count; | |
903 | if (!--next_pg_num) | |
904 | m->next_pg = pg; | |
905 | } | |
906 | ||
907 | if (pg_count != m->nr_priority_groups) { | |
72d94861 | 908 | ti->error = "priority group count mismatch"; |
1da177e4 LT |
909 | r = -EINVAL; |
910 | goto bad; | |
911 | } | |
912 | ||
55a62eef AK |
913 | ti->num_flush_bios = 1; |
914 | ti->num_discard_bios = 1; | |
042bcef8 | 915 | ti->num_write_same_bios = 1; |
8627921f | 916 | |
1da177e4 LT |
917 | return 0; |
918 | ||
919 | bad: | |
920 | free_multipath(m); | |
921 | return r; | |
922 | } | |
923 | ||
2bded7bd KU |
924 | static void multipath_wait_for_pg_init_completion(struct multipath *m) |
925 | { | |
926 | DECLARE_WAITQUEUE(wait, current); | |
927 | unsigned long flags; | |
928 | ||
929 | add_wait_queue(&m->pg_init_wait, &wait); | |
930 | ||
931 | while (1) { | |
932 | set_current_state(TASK_UNINTERRUPTIBLE); | |
933 | ||
934 | spin_lock_irqsave(&m->lock, flags); | |
935 | if (!m->pg_init_in_progress) { | |
936 | spin_unlock_irqrestore(&m->lock, flags); | |
937 | break; | |
938 | } | |
939 | spin_unlock_irqrestore(&m->lock, flags); | |
940 | ||
941 | io_schedule(); | |
942 | } | |
943 | set_current_state(TASK_RUNNING); | |
944 | ||
945 | remove_wait_queue(&m->pg_init_wait, &wait); | |
946 | } | |
947 | ||
948 | static void flush_multipath_work(struct multipath *m) | |
1da177e4 | 949 | { |
954a73d5 SKM |
950 | unsigned long flags; |
951 | ||
952 | spin_lock_irqsave(&m->lock, flags); | |
953 | m->pg_init_disabled = 1; | |
954 | spin_unlock_irqrestore(&m->lock, flags); | |
955 | ||
bab7cfc7 | 956 | flush_workqueue(kmpath_handlerd); |
2bded7bd | 957 | multipath_wait_for_pg_init_completion(m); |
a044d016 | 958 | flush_workqueue(kmultipathd); |
43829731 | 959 | flush_work(&m->trigger_event); |
954a73d5 SKM |
960 | |
961 | spin_lock_irqsave(&m->lock, flags); | |
962 | m->pg_init_disabled = 0; | |
963 | spin_unlock_irqrestore(&m->lock, flags); | |
6df400ab KU |
964 | } |
965 | ||
966 | static void multipath_dtr(struct dm_target *ti) | |
967 | { | |
968 | struct multipath *m = ti->private; | |
969 | ||
2bded7bd | 970 | flush_multipath_work(m); |
1da177e4 LT |
971 | free_multipath(m); |
972 | } | |
973 | ||
974 | /* | |
f40c67f0 | 975 | * Map cloned requests |
1da177e4 | 976 | */ |
f40c67f0 | 977 | static int multipath_map(struct dm_target *ti, struct request *clone, |
1da177e4 LT |
978 | union map_info *map_context) |
979 | { | |
980 | int r; | |
1da177e4 LT |
981 | struct multipath *m = (struct multipath *) ti->private; |
982 | ||
466891f9 | 983 | if (set_mapinfo(m, map_context) < 0) |
f40c67f0 KU |
984 | /* ENOMEM, requeue */ |
985 | return DM_MAPIO_REQUEUE; | |
1da177e4 | 986 | |
f40c67f0 | 987 | clone->cmd_flags |= REQ_FAILFAST_TRANSPORT; |
466891f9 | 988 | r = map_io(m, clone, map_context, 0); |
45e15720 | 989 | if (r < 0 || r == DM_MAPIO_REQUEUE) |
466891f9 | 990 | clear_mapinfo(m, map_context); |
1da177e4 LT |
991 | |
992 | return r; | |
993 | } | |
994 | ||
995 | /* | |
996 | * Take a path out of use. | |
997 | */ | |
998 | static int fail_path(struct pgpath *pgpath) | |
999 | { | |
1000 | unsigned long flags; | |
1001 | struct multipath *m = pgpath->pg->m; | |
1002 | ||
1003 | spin_lock_irqsave(&m->lock, flags); | |
1004 | ||
6680073d | 1005 | if (!pgpath->is_active) |
1da177e4 LT |
1006 | goto out; |
1007 | ||
72d94861 | 1008 | DMWARN("Failing path %s.", pgpath->path.dev->name); |
1da177e4 LT |
1009 | |
1010 | pgpath->pg->ps.type->fail_path(&pgpath->pg->ps, &pgpath->path); | |
6680073d | 1011 | pgpath->is_active = 0; |
1da177e4 LT |
1012 | pgpath->fail_count++; |
1013 | ||
1014 | m->nr_valid_paths--; | |
1015 | ||
1016 | if (pgpath == m->current_pgpath) | |
1017 | m->current_pgpath = NULL; | |
1018 | ||
b15546f9 MA |
1019 | dm_path_uevent(DM_UEVENT_PATH_FAILED, m->ti, |
1020 | pgpath->path.dev->name, m->nr_valid_paths); | |
1021 | ||
fe9cf30e | 1022 | schedule_work(&m->trigger_event); |
1da177e4 LT |
1023 | |
1024 | out: | |
1025 | spin_unlock_irqrestore(&m->lock, flags); | |
1026 | ||
1027 | return 0; | |
1028 | } | |
1029 | ||
1030 | /* | |
1031 | * Reinstate a previously-failed path | |
1032 | */ | |
1033 | static int reinstate_path(struct pgpath *pgpath) | |
1034 | { | |
1035 | int r = 0; | |
1036 | unsigned long flags; | |
1037 | struct multipath *m = pgpath->pg->m; | |
1038 | ||
1039 | spin_lock_irqsave(&m->lock, flags); | |
1040 | ||
6680073d | 1041 | if (pgpath->is_active) |
1da177e4 LT |
1042 | goto out; |
1043 | ||
def052d2 | 1044 | if (!pgpath->pg->ps.type->reinstate_path) { |
1da177e4 LT |
1045 | DMWARN("Reinstate path not supported by path selector %s", |
1046 | pgpath->pg->ps.type->name); | |
1047 | r = -EINVAL; | |
1048 | goto out; | |
1049 | } | |
1050 | ||
1051 | r = pgpath->pg->ps.type->reinstate_path(&pgpath->pg->ps, &pgpath->path); | |
1052 | if (r) | |
1053 | goto out; | |
1054 | ||
6680073d | 1055 | pgpath->is_active = 1; |
1da177e4 | 1056 | |
e54f77dd CS |
1057 | if (!m->nr_valid_paths++ && m->queue_size) { |
1058 | m->current_pgpath = NULL; | |
c557308e | 1059 | queue_work(kmultipathd, &m->process_queued_ios); |
e54f77dd | 1060 | } else if (m->hw_handler_name && (m->current_pg == pgpath->pg)) { |
4e2d19e4 | 1061 | if (queue_work(kmpath_handlerd, &pgpath->activate_path.work)) |
e54f77dd CS |
1062 | m->pg_init_in_progress++; |
1063 | } | |
1da177e4 | 1064 | |
b15546f9 MA |
1065 | dm_path_uevent(DM_UEVENT_PATH_REINSTATED, m->ti, |
1066 | pgpath->path.dev->name, m->nr_valid_paths); | |
1067 | ||
fe9cf30e | 1068 | schedule_work(&m->trigger_event); |
1da177e4 LT |
1069 | |
1070 | out: | |
1071 | spin_unlock_irqrestore(&m->lock, flags); | |
1072 | ||
1073 | return r; | |
1074 | } | |
1075 | ||
1076 | /* | |
1077 | * Fail or reinstate all paths that match the provided struct dm_dev. | |
1078 | */ | |
1079 | static int action_dev(struct multipath *m, struct dm_dev *dev, | |
1080 | action_fn action) | |
1081 | { | |
19040c0b | 1082 | int r = -EINVAL; |
1da177e4 LT |
1083 | struct pgpath *pgpath; |
1084 | struct priority_group *pg; | |
1085 | ||
1086 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1087 | list_for_each_entry(pgpath, &pg->pgpaths, list) { | |
1088 | if (pgpath->path.dev == dev) | |
1089 | r = action(pgpath); | |
1090 | } | |
1091 | } | |
1092 | ||
1093 | return r; | |
1094 | } | |
1095 | ||
1096 | /* | |
1097 | * Temporarily try to avoid having to use the specified PG | |
1098 | */ | |
1099 | static void bypass_pg(struct multipath *m, struct priority_group *pg, | |
1100 | int bypassed) | |
1101 | { | |
1102 | unsigned long flags; | |
1103 | ||
1104 | spin_lock_irqsave(&m->lock, flags); | |
1105 | ||
1106 | pg->bypassed = bypassed; | |
1107 | m->current_pgpath = NULL; | |
1108 | m->current_pg = NULL; | |
1109 | ||
1110 | spin_unlock_irqrestore(&m->lock, flags); | |
1111 | ||
fe9cf30e | 1112 | schedule_work(&m->trigger_event); |
1da177e4 LT |
1113 | } |
1114 | ||
1115 | /* | |
1116 | * Switch to using the specified PG from the next I/O that gets mapped | |
1117 | */ | |
1118 | static int switch_pg_num(struct multipath *m, const char *pgstr) | |
1119 | { | |
1120 | struct priority_group *pg; | |
1121 | unsigned pgnum; | |
1122 | unsigned long flags; | |
31998ef1 | 1123 | char dummy; |
1da177e4 | 1124 | |
31998ef1 | 1125 | if (!pgstr || (sscanf(pgstr, "%u%c", &pgnum, &dummy) != 1) || !pgnum || |
1da177e4 LT |
1126 | (pgnum > m->nr_priority_groups)) { |
1127 | DMWARN("invalid PG number supplied to switch_pg_num"); | |
1128 | return -EINVAL; | |
1129 | } | |
1130 | ||
1131 | spin_lock_irqsave(&m->lock, flags); | |
1132 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1133 | pg->bypassed = 0; | |
1134 | if (--pgnum) | |
1135 | continue; | |
1136 | ||
1137 | m->current_pgpath = NULL; | |
1138 | m->current_pg = NULL; | |
1139 | m->next_pg = pg; | |
1140 | } | |
1141 | spin_unlock_irqrestore(&m->lock, flags); | |
1142 | ||
fe9cf30e | 1143 | schedule_work(&m->trigger_event); |
1da177e4 LT |
1144 | return 0; |
1145 | } | |
1146 | ||
1147 | /* | |
1148 | * Set/clear bypassed status of a PG. | |
1149 | * PGs are numbered upwards from 1 in the order they were declared. | |
1150 | */ | |
1151 | static int bypass_pg_num(struct multipath *m, const char *pgstr, int bypassed) | |
1152 | { | |
1153 | struct priority_group *pg; | |
1154 | unsigned pgnum; | |
31998ef1 | 1155 | char dummy; |
1da177e4 | 1156 | |
31998ef1 | 1157 | if (!pgstr || (sscanf(pgstr, "%u%c", &pgnum, &dummy) != 1) || !pgnum || |
1da177e4 LT |
1158 | (pgnum > m->nr_priority_groups)) { |
1159 | DMWARN("invalid PG number supplied to bypass_pg"); | |
1160 | return -EINVAL; | |
1161 | } | |
1162 | ||
1163 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1164 | if (!--pgnum) | |
1165 | break; | |
1166 | } | |
1167 | ||
1168 | bypass_pg(m, pg, bypassed); | |
1169 | return 0; | |
1170 | } | |
1171 | ||
c9e45581 DW |
1172 | /* |
1173 | * Should we retry pg_init immediately? | |
1174 | */ | |
1175 | static int pg_init_limit_reached(struct multipath *m, struct pgpath *pgpath) | |
1176 | { | |
1177 | unsigned long flags; | |
1178 | int limit_reached = 0; | |
1179 | ||
1180 | spin_lock_irqsave(&m->lock, flags); | |
1181 | ||
954a73d5 | 1182 | if (m->pg_init_count <= m->pg_init_retries && !m->pg_init_disabled) |
c9e45581 DW |
1183 | m->pg_init_required = 1; |
1184 | else | |
1185 | limit_reached = 1; | |
1186 | ||
1187 | spin_unlock_irqrestore(&m->lock, flags); | |
1188 | ||
1189 | return limit_reached; | |
1190 | } | |
1191 | ||
3ae31f6a | 1192 | static void pg_init_done(void *data, int errors) |
cfae5c9b | 1193 | { |
83c0d5d5 | 1194 | struct pgpath *pgpath = data; |
cfae5c9b CS |
1195 | struct priority_group *pg = pgpath->pg; |
1196 | struct multipath *m = pg->m; | |
1197 | unsigned long flags; | |
4e2d19e4 | 1198 | unsigned delay_retry = 0; |
cfae5c9b CS |
1199 | |
1200 | /* device or driver problems */ | |
1201 | switch (errors) { | |
1202 | case SCSI_DH_OK: | |
1203 | break; | |
1204 | case SCSI_DH_NOSYS: | |
1205 | if (!m->hw_handler_name) { | |
1206 | errors = 0; | |
1207 | break; | |
1208 | } | |
f7b934c8 MB |
1209 | DMERR("Could not failover the device: Handler scsi_dh_%s " |
1210 | "Error %d.", m->hw_handler_name, errors); | |
cfae5c9b CS |
1211 | /* |
1212 | * Fail path for now, so we do not ping pong | |
1213 | */ | |
1214 | fail_path(pgpath); | |
1215 | break; | |
1216 | case SCSI_DH_DEV_TEMP_BUSY: | |
1217 | /* | |
1218 | * Probably doing something like FW upgrade on the | |
1219 | * controller so try the other pg. | |
1220 | */ | |
1221 | bypass_pg(m, pg, 1); | |
1222 | break; | |
cfae5c9b | 1223 | case SCSI_DH_RETRY: |
4e2d19e4 CS |
1224 | /* Wait before retrying. */ |
1225 | delay_retry = 1; | |
cfae5c9b CS |
1226 | case SCSI_DH_IMM_RETRY: |
1227 | case SCSI_DH_RES_TEMP_UNAVAIL: | |
1228 | if (pg_init_limit_reached(m, pgpath)) | |
1229 | fail_path(pgpath); | |
1230 | errors = 0; | |
1231 | break; | |
1232 | default: | |
1233 | /* | |
1234 | * We probably do not want to fail the path for a device | |
1235 | * error, but this is what the old dm did. In future | |
1236 | * patches we can do more advanced handling. | |
1237 | */ | |
1238 | fail_path(pgpath); | |
1239 | } | |
1240 | ||
1241 | spin_lock_irqsave(&m->lock, flags); | |
1242 | if (errors) { | |
e54f77dd CS |
1243 | if (pgpath == m->current_pgpath) { |
1244 | DMERR("Could not failover device. Error %d.", errors); | |
1245 | m->current_pgpath = NULL; | |
1246 | m->current_pg = NULL; | |
1247 | } | |
d0259bf0 | 1248 | } else if (!m->pg_init_required) |
cfae5c9b | 1249 | pg->bypassed = 0; |
cfae5c9b | 1250 | |
d0259bf0 KU |
1251 | if (--m->pg_init_in_progress) |
1252 | /* Activations of other paths are still on going */ | |
1253 | goto out; | |
1254 | ||
1255 | if (!m->pg_init_required) | |
1256 | m->queue_io = 0; | |
1257 | ||
4e2d19e4 | 1258 | m->pg_init_delay_retry = delay_retry; |
d0259bf0 KU |
1259 | queue_work(kmultipathd, &m->process_queued_ios); |
1260 | ||
2bded7bd KU |
1261 | /* |
1262 | * Wake up any thread waiting to suspend. | |
1263 | */ | |
1264 | wake_up(&m->pg_init_wait); | |
1265 | ||
d0259bf0 | 1266 | out: |
cfae5c9b CS |
1267 | spin_unlock_irqrestore(&m->lock, flags); |
1268 | } | |
1269 | ||
bab7cfc7 CS |
1270 | static void activate_path(struct work_struct *work) |
1271 | { | |
e54f77dd | 1272 | struct pgpath *pgpath = |
4e2d19e4 | 1273 | container_of(work, struct pgpath, activate_path.work); |
bab7cfc7 | 1274 | |
3ae31f6a | 1275 | scsi_dh_activate(bdev_get_queue(pgpath->path.dev->bdev), |
83c0d5d5 | 1276 | pg_init_done, pgpath); |
bab7cfc7 CS |
1277 | } |
1278 | ||
7e782af5 HR |
1279 | static int noretry_error(int error) |
1280 | { | |
1281 | switch (error) { | |
1282 | case -EOPNOTSUPP: | |
1283 | case -EREMOTEIO: | |
1284 | case -EILSEQ: | |
1285 | case -ENODATA: | |
cc9d3c38 | 1286 | case -ENOSPC: |
7e782af5 HR |
1287 | return 1; |
1288 | } | |
1289 | ||
1290 | /* Anything else could be a path failure, so should be retried */ | |
1291 | return 0; | |
1292 | } | |
1293 | ||
1da177e4 LT |
1294 | /* |
1295 | * end_io handling | |
1296 | */ | |
f40c67f0 | 1297 | static int do_end_io(struct multipath *m, struct request *clone, |
028867ac | 1298 | int error, struct dm_mpath_io *mpio) |
1da177e4 | 1299 | { |
f40c67f0 KU |
1300 | /* |
1301 | * We don't queue any clone request inside the multipath target | |
1302 | * during end I/O handling, since those clone requests don't have | |
1303 | * bio clones. If we queue them inside the multipath target, | |
1304 | * we need to make bio clones, that requires memory allocation. | |
1305 | * (See drivers/md/dm.c:end_clone_bio() about why the clone requests | |
1306 | * don't have bio clones.) | |
1307 | * Instead of queueing the clone request here, we queue the original | |
1308 | * request into dm core, which will remake a clone request and | |
1309 | * clone bios for it and resubmit it later. | |
1310 | */ | |
1311 | int r = DM_ENDIO_REQUEUE; | |
640eb3b0 | 1312 | unsigned long flags; |
1da177e4 | 1313 | |
f40c67f0 | 1314 | if (!error && !clone->errors) |
1da177e4 LT |
1315 | return 0; /* I/O complete */ |
1316 | ||
f84cb8a4 MS |
1317 | if (noretry_error(error)) { |
1318 | if ((clone->cmd_flags & REQ_WRITE_SAME) && | |
1319 | !clone->q->limits.max_write_same_sectors) { | |
1320 | struct queue_limits *limits; | |
1321 | ||
1322 | /* device doesn't really support WRITE SAME, disable it */ | |
1323 | limits = dm_get_queue_limits(dm_table_get_md(m->ti->table)); | |
1324 | limits->max_write_same_sectors = 0; | |
1325 | } | |
959eb4e5 | 1326 | return error; |
f84cb8a4 | 1327 | } |
959eb4e5 | 1328 | |
cfae5c9b CS |
1329 | if (mpio->pgpath) |
1330 | fail_path(mpio->pgpath); | |
1da177e4 | 1331 | |
640eb3b0 | 1332 | spin_lock_irqsave(&m->lock, flags); |
751b2a7d HR |
1333 | if (!m->nr_valid_paths) { |
1334 | if (!m->queue_if_no_path) { | |
1335 | if (!__must_push_back(m)) | |
1336 | r = -EIO; | |
1337 | } else { | |
1338 | if (error == -EBADE) | |
1339 | r = error; | |
1340 | } | |
1341 | } | |
640eb3b0 | 1342 | spin_unlock_irqrestore(&m->lock, flags); |
1da177e4 | 1343 | |
f40c67f0 | 1344 | return r; |
1da177e4 LT |
1345 | } |
1346 | ||
f40c67f0 | 1347 | static int multipath_end_io(struct dm_target *ti, struct request *clone, |
1da177e4 LT |
1348 | int error, union map_info *map_context) |
1349 | { | |
028867ac AK |
1350 | struct multipath *m = ti->private; |
1351 | struct dm_mpath_io *mpio = map_context->ptr; | |
a71a261f | 1352 | struct pgpath *pgpath; |
1da177e4 LT |
1353 | struct path_selector *ps; |
1354 | int r; | |
1355 | ||
466891f9 JN |
1356 | BUG_ON(!mpio); |
1357 | ||
f40c67f0 | 1358 | r = do_end_io(m, clone, error, mpio); |
a71a261f | 1359 | pgpath = mpio->pgpath; |
1da177e4 LT |
1360 | if (pgpath) { |
1361 | ps = &pgpath->pg->ps; | |
1362 | if (ps->type->end_io) | |
02ab823f | 1363 | ps->type->end_io(ps, &pgpath->path, mpio->nr_bytes); |
1da177e4 | 1364 | } |
466891f9 | 1365 | clear_mapinfo(m, map_context); |
1da177e4 LT |
1366 | |
1367 | return r; | |
1368 | } | |
1369 | ||
1370 | /* | |
1371 | * Suspend can't complete until all the I/O is processed so if | |
436d4108 AK |
1372 | * the last path fails we must error any remaining I/O. |
1373 | * Note that if the freeze_bdev fails while suspending, the | |
1374 | * queue_if_no_path state is lost - userspace should reset it. | |
1da177e4 LT |
1375 | */ |
1376 | static void multipath_presuspend(struct dm_target *ti) | |
1377 | { | |
1378 | struct multipath *m = (struct multipath *) ti->private; | |
1da177e4 | 1379 | |
485ef69e | 1380 | queue_if_no_path(m, 0, 1); |
1da177e4 LT |
1381 | } |
1382 | ||
6df400ab KU |
1383 | static void multipath_postsuspend(struct dm_target *ti) |
1384 | { | |
6380f26f MA |
1385 | struct multipath *m = ti->private; |
1386 | ||
1387 | mutex_lock(&m->work_mutex); | |
2bded7bd | 1388 | flush_multipath_work(m); |
6380f26f | 1389 | mutex_unlock(&m->work_mutex); |
6df400ab KU |
1390 | } |
1391 | ||
436d4108 AK |
1392 | /* |
1393 | * Restore the queue_if_no_path setting. | |
1394 | */ | |
1da177e4 LT |
1395 | static void multipath_resume(struct dm_target *ti) |
1396 | { | |
1397 | struct multipath *m = (struct multipath *) ti->private; | |
1398 | unsigned long flags; | |
1399 | ||
1400 | spin_lock_irqsave(&m->lock, flags); | |
436d4108 | 1401 | m->queue_if_no_path = m->saved_queue_if_no_path; |
1da177e4 LT |
1402 | spin_unlock_irqrestore(&m->lock, flags); |
1403 | } | |
1404 | ||
1405 | /* | |
1406 | * Info output has the following format: | |
1407 | * num_multipath_feature_args [multipath_feature_args]* | |
1408 | * num_handler_status_args [handler_status_args]* | |
1409 | * num_groups init_group_number | |
1410 | * [A|D|E num_ps_status_args [ps_status_args]* | |
1411 | * num_paths num_selector_args | |
1412 | * [path_dev A|F fail_count [selector_args]* ]+ ]+ | |
1413 | * | |
1414 | * Table output has the following format (identical to the constructor string): | |
1415 | * num_feature_args [features_args]* | |
1416 | * num_handler_args hw_handler [hw_handler_args]* | |
1417 | * num_groups init_group_number | |
1418 | * [priority selector-name num_ps_args [ps_args]* | |
1419 | * num_paths num_selector_args [path_dev [selector_args]* ]+ ]+ | |
1420 | */ | |
fd7c092e MP |
1421 | static void multipath_status(struct dm_target *ti, status_type_t type, |
1422 | unsigned status_flags, char *result, unsigned maxlen) | |
1da177e4 LT |
1423 | { |
1424 | int sz = 0; | |
1425 | unsigned long flags; | |
1426 | struct multipath *m = (struct multipath *) ti->private; | |
1da177e4 LT |
1427 | struct priority_group *pg; |
1428 | struct pgpath *p; | |
1429 | unsigned pg_num; | |
1430 | char state; | |
1431 | ||
1432 | spin_lock_irqsave(&m->lock, flags); | |
1433 | ||
1434 | /* Features */ | |
1435 | if (type == STATUSTYPE_INFO) | |
c9e45581 DW |
1436 | DMEMIT("2 %u %u ", m->queue_size, m->pg_init_count); |
1437 | else { | |
1438 | DMEMIT("%u ", m->queue_if_no_path + | |
4e2d19e4 | 1439 | (m->pg_init_retries > 0) * 2 + |
a58a935d MS |
1440 | (m->pg_init_delay_msecs != DM_PG_INIT_DELAY_DEFAULT) * 2 + |
1441 | m->retain_attached_hw_handler); | |
c9e45581 DW |
1442 | if (m->queue_if_no_path) |
1443 | DMEMIT("queue_if_no_path "); | |
1444 | if (m->pg_init_retries) | |
1445 | DMEMIT("pg_init_retries %u ", m->pg_init_retries); | |
4e2d19e4 CS |
1446 | if (m->pg_init_delay_msecs != DM_PG_INIT_DELAY_DEFAULT) |
1447 | DMEMIT("pg_init_delay_msecs %u ", m->pg_init_delay_msecs); | |
a58a935d MS |
1448 | if (m->retain_attached_hw_handler) |
1449 | DMEMIT("retain_attached_hw_handler "); | |
c9e45581 | 1450 | } |
1da177e4 | 1451 | |
cfae5c9b | 1452 | if (!m->hw_handler_name || type == STATUSTYPE_INFO) |
1da177e4 LT |
1453 | DMEMIT("0 "); |
1454 | else | |
cfae5c9b | 1455 | DMEMIT("1 %s ", m->hw_handler_name); |
1da177e4 LT |
1456 | |
1457 | DMEMIT("%u ", m->nr_priority_groups); | |
1458 | ||
1459 | if (m->next_pg) | |
1460 | pg_num = m->next_pg->pg_num; | |
1461 | else if (m->current_pg) | |
1462 | pg_num = m->current_pg->pg_num; | |
1463 | else | |
a490a07a | 1464 | pg_num = (m->nr_priority_groups ? 1 : 0); |
1da177e4 LT |
1465 | |
1466 | DMEMIT("%u ", pg_num); | |
1467 | ||
1468 | switch (type) { | |
1469 | case STATUSTYPE_INFO: | |
1470 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1471 | if (pg->bypassed) | |
1472 | state = 'D'; /* Disabled */ | |
1473 | else if (pg == m->current_pg) | |
1474 | state = 'A'; /* Currently Active */ | |
1475 | else | |
1476 | state = 'E'; /* Enabled */ | |
1477 | ||
1478 | DMEMIT("%c ", state); | |
1479 | ||
1480 | if (pg->ps.type->status) | |
1481 | sz += pg->ps.type->status(&pg->ps, NULL, type, | |
1482 | result + sz, | |
1483 | maxlen - sz); | |
1484 | else | |
1485 | DMEMIT("0 "); | |
1486 | ||
1487 | DMEMIT("%u %u ", pg->nr_pgpaths, | |
1488 | pg->ps.type->info_args); | |
1489 | ||
1490 | list_for_each_entry(p, &pg->pgpaths, list) { | |
1491 | DMEMIT("%s %s %u ", p->path.dev->name, | |
6680073d | 1492 | p->is_active ? "A" : "F", |
1da177e4 LT |
1493 | p->fail_count); |
1494 | if (pg->ps.type->status) | |
1495 | sz += pg->ps.type->status(&pg->ps, | |
1496 | &p->path, type, result + sz, | |
1497 | maxlen - sz); | |
1498 | } | |
1499 | } | |
1500 | break; | |
1501 | ||
1502 | case STATUSTYPE_TABLE: | |
1503 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1504 | DMEMIT("%s ", pg->ps.type->name); | |
1505 | ||
1506 | if (pg->ps.type->status) | |
1507 | sz += pg->ps.type->status(&pg->ps, NULL, type, | |
1508 | result + sz, | |
1509 | maxlen - sz); | |
1510 | else | |
1511 | DMEMIT("0 "); | |
1512 | ||
1513 | DMEMIT("%u %u ", pg->nr_pgpaths, | |
1514 | pg->ps.type->table_args); | |
1515 | ||
1516 | list_for_each_entry(p, &pg->pgpaths, list) { | |
1517 | DMEMIT("%s ", p->path.dev->name); | |
1518 | if (pg->ps.type->status) | |
1519 | sz += pg->ps.type->status(&pg->ps, | |
1520 | &p->path, type, result + sz, | |
1521 | maxlen - sz); | |
1522 | } | |
1523 | } | |
1524 | break; | |
1525 | } | |
1526 | ||
1527 | spin_unlock_irqrestore(&m->lock, flags); | |
1da177e4 LT |
1528 | } |
1529 | ||
1530 | static int multipath_message(struct dm_target *ti, unsigned argc, char **argv) | |
1531 | { | |
6380f26f | 1532 | int r = -EINVAL; |
1da177e4 LT |
1533 | struct dm_dev *dev; |
1534 | struct multipath *m = (struct multipath *) ti->private; | |
1535 | action_fn action; | |
1536 | ||
6380f26f MA |
1537 | mutex_lock(&m->work_mutex); |
1538 | ||
c2f3d24b KU |
1539 | if (dm_suspended(ti)) { |
1540 | r = -EBUSY; | |
1541 | goto out; | |
1542 | } | |
1543 | ||
1da177e4 | 1544 | if (argc == 1) { |
498f0103 | 1545 | if (!strcasecmp(argv[0], "queue_if_no_path")) { |
6380f26f MA |
1546 | r = queue_if_no_path(m, 1, 0); |
1547 | goto out; | |
498f0103 | 1548 | } else if (!strcasecmp(argv[0], "fail_if_no_path")) { |
6380f26f MA |
1549 | r = queue_if_no_path(m, 0, 0); |
1550 | goto out; | |
1551 | } | |
1da177e4 LT |
1552 | } |
1553 | ||
6380f26f MA |
1554 | if (argc != 2) { |
1555 | DMWARN("Unrecognised multipath message received."); | |
1556 | goto out; | |
1557 | } | |
1da177e4 | 1558 | |
498f0103 | 1559 | if (!strcasecmp(argv[0], "disable_group")) { |
6380f26f MA |
1560 | r = bypass_pg_num(m, argv[1], 1); |
1561 | goto out; | |
498f0103 | 1562 | } else if (!strcasecmp(argv[0], "enable_group")) { |
6380f26f MA |
1563 | r = bypass_pg_num(m, argv[1], 0); |
1564 | goto out; | |
498f0103 | 1565 | } else if (!strcasecmp(argv[0], "switch_group")) { |
6380f26f MA |
1566 | r = switch_pg_num(m, argv[1]); |
1567 | goto out; | |
498f0103 | 1568 | } else if (!strcasecmp(argv[0], "reinstate_path")) |
1da177e4 | 1569 | action = reinstate_path; |
498f0103 | 1570 | else if (!strcasecmp(argv[0], "fail_path")) |
1da177e4 | 1571 | action = fail_path; |
6380f26f MA |
1572 | else { |
1573 | DMWARN("Unrecognised multipath message received."); | |
1574 | goto out; | |
1575 | } | |
1da177e4 | 1576 | |
8215d6ec | 1577 | r = dm_get_device(ti, argv[1], dm_table_get_mode(ti->table), &dev); |
1da177e4 | 1578 | if (r) { |
72d94861 | 1579 | DMWARN("message: error getting device %s", |
1da177e4 | 1580 | argv[1]); |
6380f26f | 1581 | goto out; |
1da177e4 LT |
1582 | } |
1583 | ||
1584 | r = action_dev(m, dev, action); | |
1585 | ||
1586 | dm_put_device(ti, dev); | |
1587 | ||
6380f26f MA |
1588 | out: |
1589 | mutex_unlock(&m->work_mutex); | |
1da177e4 | 1590 | return r; |
1da177e4 LT |
1591 | } |
1592 | ||
647b3d00 | 1593 | static int multipath_ioctl(struct dm_target *ti, unsigned int cmd, |
9af4aa30 MB |
1594 | unsigned long arg) |
1595 | { | |
35991652 | 1596 | struct multipath *m = ti->private; |
7ba10aa6 | 1597 | struct pgpath *pgpath; |
35991652 MP |
1598 | struct block_device *bdev; |
1599 | fmode_t mode; | |
9af4aa30 | 1600 | unsigned long flags; |
35991652 MP |
1601 | int r; |
1602 | ||
35991652 MP |
1603 | bdev = NULL; |
1604 | mode = 0; | |
1605 | r = 0; | |
9af4aa30 MB |
1606 | |
1607 | spin_lock_irqsave(&m->lock, flags); | |
1608 | ||
1609 | if (!m->current_pgpath) | |
02ab823f | 1610 | __choose_pgpath(m, 0); |
9af4aa30 | 1611 | |
7ba10aa6 MS |
1612 | pgpath = m->current_pgpath; |
1613 | ||
1614 | if (pgpath) { | |
1615 | bdev = pgpath->path.dev->bdev; | |
1616 | mode = pgpath->path.dev->mode; | |
e90dae1f | 1617 | } |
9af4aa30 | 1618 | |
7ba10aa6 | 1619 | if ((pgpath && m->queue_io) || (!pgpath && m->queue_if_no_path)) |
6c182cd8 | 1620 | r = -ENOTCONN; |
9af4aa30 MB |
1621 | else if (!bdev) |
1622 | r = -EIO; | |
1623 | ||
1624 | spin_unlock_irqrestore(&m->lock, flags); | |
1625 | ||
ec8013be PB |
1626 | /* |
1627 | * Only pass ioctls through if the device sizes match exactly. | |
1628 | */ | |
1629 | if (!r && ti->len != i_size_read(bdev->bd_inode) >> SECTOR_SHIFT) | |
1630 | r = scsi_verify_blk_ioctl(NULL, cmd); | |
1631 | ||
6c182cd8 | 1632 | if (r == -ENOTCONN && !fatal_signal_pending(current)) |
35991652 | 1633 | queue_work(kmultipathd, &m->process_queued_ios); |
35991652 | 1634 | |
633a08b8 | 1635 | return r ? : __blkdev_driver_ioctl(bdev, mode, cmd, arg); |
9af4aa30 MB |
1636 | } |
1637 | ||
af4874e0 MS |
1638 | static int multipath_iterate_devices(struct dm_target *ti, |
1639 | iterate_devices_callout_fn fn, void *data) | |
1640 | { | |
1641 | struct multipath *m = ti->private; | |
1642 | struct priority_group *pg; | |
1643 | struct pgpath *p; | |
1644 | int ret = 0; | |
1645 | ||
1646 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1647 | list_for_each_entry(p, &pg->pgpaths, list) { | |
5dea271b | 1648 | ret = fn(ti, p->path.dev, ti->begin, ti->len, data); |
af4874e0 MS |
1649 | if (ret) |
1650 | goto out; | |
1651 | } | |
1652 | } | |
1653 | ||
1654 | out: | |
1655 | return ret; | |
1656 | } | |
1657 | ||
f40c67f0 KU |
1658 | static int __pgpath_busy(struct pgpath *pgpath) |
1659 | { | |
1660 | struct request_queue *q = bdev_get_queue(pgpath->path.dev->bdev); | |
1661 | ||
1662 | return dm_underlying_device_busy(q); | |
1663 | } | |
1664 | ||
1665 | /* | |
1666 | * We return "busy", only when we can map I/Os but underlying devices | |
1667 | * are busy (so even if we map I/Os now, the I/Os will wait on | |
1668 | * the underlying queue). | |
1669 | * In other words, if we want to kill I/Os or queue them inside us | |
1670 | * due to map unavailability, we don't return "busy". Otherwise, | |
1671 | * dm core won't give us the I/Os and we can't do what we want. | |
1672 | */ | |
1673 | static int multipath_busy(struct dm_target *ti) | |
1674 | { | |
1675 | int busy = 0, has_active = 0; | |
1676 | struct multipath *m = ti->private; | |
1677 | struct priority_group *pg; | |
1678 | struct pgpath *pgpath; | |
1679 | unsigned long flags; | |
1680 | ||
1681 | spin_lock_irqsave(&m->lock, flags); | |
1682 | ||
b63349a7 HR |
1683 | /* pg_init in progress, requeue until done */ |
1684 | if (m->pg_init_in_progress) { | |
1685 | busy = 1; | |
1686 | goto out; | |
1687 | } | |
f40c67f0 KU |
1688 | /* Guess which priority_group will be used at next mapping time */ |
1689 | if (unlikely(!m->current_pgpath && m->next_pg)) | |
1690 | pg = m->next_pg; | |
1691 | else if (likely(m->current_pg)) | |
1692 | pg = m->current_pg; | |
1693 | else | |
1694 | /* | |
1695 | * We don't know which pg will be used at next mapping time. | |
1696 | * We don't call __choose_pgpath() here to avoid to trigger | |
1697 | * pg_init just by busy checking. | |
1698 | * So we don't know whether underlying devices we will be using | |
1699 | * at next mapping time are busy or not. Just try mapping. | |
1700 | */ | |
1701 | goto out; | |
1702 | ||
1703 | /* | |
1704 | * If there is one non-busy active path at least, the path selector | |
1705 | * will be able to select it. So we consider such a pg as not busy. | |
1706 | */ | |
1707 | busy = 1; | |
1708 | list_for_each_entry(pgpath, &pg->pgpaths, list) | |
1709 | if (pgpath->is_active) { | |
1710 | has_active = 1; | |
1711 | ||
1712 | if (!__pgpath_busy(pgpath)) { | |
1713 | busy = 0; | |
1714 | break; | |
1715 | } | |
1716 | } | |
1717 | ||
1718 | if (!has_active) | |
1719 | /* | |
1720 | * No active path in this pg, so this pg won't be used and | |
1721 | * the current_pg will be changed at next mapping time. | |
1722 | * We need to try mapping to determine it. | |
1723 | */ | |
1724 | busy = 0; | |
1725 | ||
1726 | out: | |
1727 | spin_unlock_irqrestore(&m->lock, flags); | |
1728 | ||
1729 | return busy; | |
1730 | } | |
1731 | ||
1da177e4 LT |
1732 | /*----------------------------------------------------------------- |
1733 | * Module setup | |
1734 | *---------------------------------------------------------------*/ | |
1735 | static struct target_type multipath_target = { | |
1736 | .name = "multipath", | |
954a73d5 | 1737 | .version = {1, 6, 0}, |
1da177e4 LT |
1738 | .module = THIS_MODULE, |
1739 | .ctr = multipath_ctr, | |
1740 | .dtr = multipath_dtr, | |
f40c67f0 KU |
1741 | .map_rq = multipath_map, |
1742 | .rq_end_io = multipath_end_io, | |
1da177e4 | 1743 | .presuspend = multipath_presuspend, |
6df400ab | 1744 | .postsuspend = multipath_postsuspend, |
1da177e4 LT |
1745 | .resume = multipath_resume, |
1746 | .status = multipath_status, | |
1747 | .message = multipath_message, | |
9af4aa30 | 1748 | .ioctl = multipath_ioctl, |
af4874e0 | 1749 | .iterate_devices = multipath_iterate_devices, |
f40c67f0 | 1750 | .busy = multipath_busy, |
1da177e4 LT |
1751 | }; |
1752 | ||
1753 | static int __init dm_multipath_init(void) | |
1754 | { | |
1755 | int r; | |
1756 | ||
1757 | /* allocate a slab for the dm_ios */ | |
028867ac | 1758 | _mpio_cache = KMEM_CACHE(dm_mpath_io, 0); |
1da177e4 LT |
1759 | if (!_mpio_cache) |
1760 | return -ENOMEM; | |
1761 | ||
1762 | r = dm_register_target(&multipath_target); | |
1763 | if (r < 0) { | |
0cd33124 | 1764 | DMERR("register failed %d", r); |
1da177e4 LT |
1765 | kmem_cache_destroy(_mpio_cache); |
1766 | return -EINVAL; | |
1767 | } | |
1768 | ||
4d4d66ab | 1769 | kmultipathd = alloc_workqueue("kmpathd", WQ_MEM_RECLAIM, 0); |
c557308e | 1770 | if (!kmultipathd) { |
0cd33124 | 1771 | DMERR("failed to create workqueue kmpathd"); |
c557308e AK |
1772 | dm_unregister_target(&multipath_target); |
1773 | kmem_cache_destroy(_mpio_cache); | |
1774 | return -ENOMEM; | |
1775 | } | |
1776 | ||
bab7cfc7 CS |
1777 | /* |
1778 | * A separate workqueue is used to handle the device handlers | |
1779 | * to avoid overloading existing workqueue. Overloading the | |
1780 | * old workqueue would also create a bottleneck in the | |
1781 | * path of the storage hardware device activation. | |
1782 | */ | |
4d4d66ab TH |
1783 | kmpath_handlerd = alloc_ordered_workqueue("kmpath_handlerd", |
1784 | WQ_MEM_RECLAIM); | |
bab7cfc7 CS |
1785 | if (!kmpath_handlerd) { |
1786 | DMERR("failed to create workqueue kmpath_handlerd"); | |
1787 | destroy_workqueue(kmultipathd); | |
1788 | dm_unregister_target(&multipath_target); | |
1789 | kmem_cache_destroy(_mpio_cache); | |
1790 | return -ENOMEM; | |
1791 | } | |
1792 | ||
72d94861 | 1793 | DMINFO("version %u.%u.%u loaded", |
1da177e4 LT |
1794 | multipath_target.version[0], multipath_target.version[1], |
1795 | multipath_target.version[2]); | |
1796 | ||
1797 | return r; | |
1798 | } | |
1799 | ||
1800 | static void __exit dm_multipath_exit(void) | |
1801 | { | |
bab7cfc7 | 1802 | destroy_workqueue(kmpath_handlerd); |
c557308e AK |
1803 | destroy_workqueue(kmultipathd); |
1804 | ||
10d3bd09 | 1805 | dm_unregister_target(&multipath_target); |
1da177e4 LT |
1806 | kmem_cache_destroy(_mpio_cache); |
1807 | } | |
1808 | ||
1da177e4 LT |
1809 | module_init(dm_multipath_init); |
1810 | module_exit(dm_multipath_exit); | |
1811 | ||
1812 | MODULE_DESCRIPTION(DM_NAME " multipath target"); | |
1813 | MODULE_AUTHOR("Sistina Software <dm-devel@redhat.com>"); | |
1814 | MODULE_LICENSE("GPL"); |