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 | 13 | |
e5863d9a | 14 | #include <linux/blkdev.h> |
1da177e4 LT |
15 | #include <linux/ctype.h> |
16 | #include <linux/init.h> | |
17 | #include <linux/mempool.h> | |
18 | #include <linux/module.h> | |
19 | #include <linux/pagemap.h> | |
20 | #include <linux/slab.h> | |
21 | #include <linux/time.h> | |
22 | #include <linux/workqueue.h> | |
35991652 | 23 | #include <linux/delay.h> |
cfae5c9b | 24 | #include <scsi/scsi_dh.h> |
60063497 | 25 | #include <linux/atomic.h> |
1da177e4 | 26 | |
72d94861 | 27 | #define DM_MSG_PREFIX "multipath" |
4e2d19e4 CS |
28 | #define DM_PG_INIT_DELAY_MSECS 2000 |
29 | #define DM_PG_INIT_DELAY_DEFAULT ((unsigned) -1) | |
1da177e4 LT |
30 | |
31 | /* Path properties */ | |
32 | struct pgpath { | |
33 | struct list_head list; | |
34 | ||
35 | struct priority_group *pg; /* Owning PG */ | |
6680073d | 36 | unsigned is_active; /* Path status */ |
1da177e4 LT |
37 | unsigned fail_count; /* Cumulative failure count */ |
38 | ||
c922d5f7 | 39 | struct dm_path path; |
4e2d19e4 | 40 | struct delayed_work activate_path; |
1da177e4 LT |
41 | }; |
42 | ||
43 | #define path_to_pgpath(__pgp) container_of((__pgp), struct pgpath, path) | |
44 | ||
45 | /* | |
46 | * Paths are grouped into Priority Groups and numbered from 1 upwards. | |
47 | * Each has a path selector which controls which path gets used. | |
48 | */ | |
49 | struct priority_group { | |
50 | struct list_head list; | |
51 | ||
52 | struct multipath *m; /* Owning multipath instance */ | |
53 | struct path_selector ps; | |
54 | ||
55 | unsigned pg_num; /* Reference number */ | |
56 | unsigned bypassed; /* Temporarily bypass this PG? */ | |
57 | ||
58 | unsigned nr_pgpaths; /* Number of paths in PG */ | |
59 | struct list_head pgpaths; | |
60 | }; | |
61 | ||
62 | /* Multipath context */ | |
63 | struct multipath { | |
64 | struct list_head list; | |
65 | struct dm_target *ti; | |
66 | ||
cfae5c9b | 67 | const char *hw_handler_name; |
2bfd2e13 | 68 | char *hw_handler_params; |
4e2d19e4 | 69 | |
1fbdd2b3 MS |
70 | spinlock_t lock; |
71 | ||
1da177e4 LT |
72 | unsigned nr_priority_groups; |
73 | struct list_head priority_groups; | |
4e2d19e4 CS |
74 | |
75 | wait_queue_head_t pg_init_wait; /* Wait for pg_init completion */ | |
76 | ||
1da177e4 | 77 | unsigned pg_init_required; /* pg_init needs calling? */ |
c3cd4f6b | 78 | unsigned pg_init_in_progress; /* Only one pg_init allowed at once */ |
4e2d19e4 | 79 | unsigned pg_init_delay_retry; /* Delay pg_init retry? */ |
1da177e4 LT |
80 | |
81 | unsigned nr_valid_paths; /* Total number of usable paths */ | |
82 | struct pgpath *current_pgpath; | |
83 | struct priority_group *current_pg; | |
84 | struct priority_group *next_pg; /* Switch to this PG if set */ | |
85 | unsigned repeat_count; /* I/Os left before calling PS again */ | |
86 | ||
1fbdd2b3 MS |
87 | unsigned queue_io:1; /* Must we queue all I/O? */ |
88 | unsigned queue_if_no_path:1; /* Queue I/O if last path fails? */ | |
89 | unsigned saved_queue_if_no_path:1; /* Saved state during suspension */ | |
a58a935d | 90 | unsigned retain_attached_hw_handler:1; /* If there's already a hw_handler present, don't change it. */ |
954a73d5 | 91 | unsigned pg_init_disabled:1; /* pg_init is not currently allowed */ |
1fbdd2b3 | 92 | |
c9e45581 DW |
93 | unsigned pg_init_retries; /* Number of times to retry pg_init */ |
94 | unsigned pg_init_count; /* Number of times pg_init called */ | |
4e2d19e4 | 95 | unsigned pg_init_delay_msecs; /* Number of msecs before pg_init retry */ |
1da177e4 | 96 | |
1da177e4 LT |
97 | struct work_struct trigger_event; |
98 | ||
99 | /* | |
028867ac | 100 | * We must use a mempool of dm_mpath_io structs so that we |
1da177e4 LT |
101 | * can resubmit bios on error. |
102 | */ | |
103 | mempool_t *mpio_pool; | |
6380f26f MA |
104 | |
105 | struct mutex work_mutex; | |
1da177e4 LT |
106 | }; |
107 | ||
108 | /* | |
109 | * Context information attached to each bio we process. | |
110 | */ | |
028867ac | 111 | struct dm_mpath_io { |
1da177e4 | 112 | struct pgpath *pgpath; |
02ab823f | 113 | size_t nr_bytes; |
1da177e4 LT |
114 | }; |
115 | ||
116 | typedef int (*action_fn) (struct pgpath *pgpath); | |
117 | ||
e18b890b | 118 | static struct kmem_cache *_mpio_cache; |
1da177e4 | 119 | |
bab7cfc7 | 120 | static struct workqueue_struct *kmultipathd, *kmpath_handlerd; |
c4028958 | 121 | static void trigger_event(struct work_struct *work); |
bab7cfc7 | 122 | static void activate_path(struct work_struct *work); |
e8099177 | 123 | static int __pgpath_busy(struct pgpath *pgpath); |
1da177e4 LT |
124 | |
125 | ||
126 | /*----------------------------------------------- | |
127 | * Allocation routines | |
128 | *-----------------------------------------------*/ | |
129 | ||
130 | static struct pgpath *alloc_pgpath(void) | |
131 | { | |
e69fae56 | 132 | struct pgpath *pgpath = kzalloc(sizeof(*pgpath), GFP_KERNEL); |
1da177e4 | 133 | |
224cb3e9 | 134 | if (pgpath) { |
6680073d | 135 | pgpath->is_active = 1; |
4e2d19e4 | 136 | INIT_DELAYED_WORK(&pgpath->activate_path, activate_path); |
224cb3e9 | 137 | } |
1da177e4 LT |
138 | |
139 | return pgpath; | |
140 | } | |
141 | ||
028867ac | 142 | static void free_pgpath(struct pgpath *pgpath) |
1da177e4 LT |
143 | { |
144 | kfree(pgpath); | |
145 | } | |
146 | ||
147 | static struct priority_group *alloc_priority_group(void) | |
148 | { | |
149 | struct priority_group *pg; | |
150 | ||
e69fae56 | 151 | pg = kzalloc(sizeof(*pg), GFP_KERNEL); |
1da177e4 | 152 | |
e69fae56 MM |
153 | if (pg) |
154 | INIT_LIST_HEAD(&pg->pgpaths); | |
1da177e4 LT |
155 | |
156 | return pg; | |
157 | } | |
158 | ||
159 | static void free_pgpaths(struct list_head *pgpaths, struct dm_target *ti) | |
160 | { | |
161 | struct pgpath *pgpath, *tmp; | |
162 | ||
163 | list_for_each_entry_safe(pgpath, tmp, pgpaths, list) { | |
164 | list_del(&pgpath->list); | |
165 | dm_put_device(ti, pgpath->path.dev); | |
166 | free_pgpath(pgpath); | |
167 | } | |
168 | } | |
169 | ||
170 | static void free_priority_group(struct priority_group *pg, | |
171 | struct dm_target *ti) | |
172 | { | |
173 | struct path_selector *ps = &pg->ps; | |
174 | ||
175 | if (ps->type) { | |
176 | ps->type->destroy(ps); | |
177 | dm_put_path_selector(ps->type); | |
178 | } | |
179 | ||
180 | free_pgpaths(&pg->pgpaths, ti); | |
181 | kfree(pg); | |
182 | } | |
183 | ||
28f16c20 | 184 | static struct multipath *alloc_multipath(struct dm_target *ti) |
1da177e4 LT |
185 | { |
186 | struct multipath *m; | |
f4790826 | 187 | unsigned min_ios = dm_get_reserved_rq_based_ios(); |
1da177e4 | 188 | |
e69fae56 | 189 | m = kzalloc(sizeof(*m), GFP_KERNEL); |
1da177e4 | 190 | if (m) { |
1da177e4 LT |
191 | INIT_LIST_HEAD(&m->priority_groups); |
192 | spin_lock_init(&m->lock); | |
193 | m->queue_io = 1; | |
4e2d19e4 | 194 | m->pg_init_delay_msecs = DM_PG_INIT_DELAY_DEFAULT; |
c4028958 | 195 | INIT_WORK(&m->trigger_event, trigger_event); |
2bded7bd | 196 | init_waitqueue_head(&m->pg_init_wait); |
6380f26f | 197 | mutex_init(&m->work_mutex); |
f4790826 | 198 | m->mpio_pool = mempool_create_slab_pool(min_ios, _mpio_cache); |
1da177e4 LT |
199 | if (!m->mpio_pool) { |
200 | kfree(m); | |
201 | return NULL; | |
202 | } | |
28f16c20 MM |
203 | m->ti = ti; |
204 | ti->private = m; | |
1da177e4 LT |
205 | } |
206 | ||
207 | return m; | |
208 | } | |
209 | ||
210 | static void free_multipath(struct multipath *m) | |
211 | { | |
212 | struct priority_group *pg, *tmp; | |
1da177e4 LT |
213 | |
214 | list_for_each_entry_safe(pg, tmp, &m->priority_groups, list) { | |
215 | list_del(&pg->list); | |
216 | free_priority_group(pg, m->ti); | |
217 | } | |
218 | ||
cfae5c9b | 219 | kfree(m->hw_handler_name); |
2bfd2e13 | 220 | kfree(m->hw_handler_params); |
1da177e4 LT |
221 | mempool_destroy(m->mpio_pool); |
222 | kfree(m); | |
223 | } | |
224 | ||
466891f9 JN |
225 | static int set_mapinfo(struct multipath *m, union map_info *info) |
226 | { | |
227 | struct dm_mpath_io *mpio; | |
228 | ||
229 | mpio = mempool_alloc(m->mpio_pool, GFP_ATOMIC); | |
230 | if (!mpio) | |
231 | return -ENOMEM; | |
232 | ||
233 | memset(mpio, 0, sizeof(*mpio)); | |
234 | info->ptr = mpio; | |
235 | ||
236 | return 0; | |
237 | } | |
238 | ||
239 | static void clear_mapinfo(struct multipath *m, union map_info *info) | |
240 | { | |
241 | struct dm_mpath_io *mpio = info->ptr; | |
242 | ||
243 | info->ptr = NULL; | |
244 | mempool_free(mpio, m->mpio_pool); | |
245 | } | |
1da177e4 LT |
246 | |
247 | /*----------------------------------------------- | |
248 | * Path selection | |
249 | *-----------------------------------------------*/ | |
250 | ||
3e9f1be1 | 251 | static int __pg_init_all_paths(struct multipath *m) |
fb612642 KU |
252 | { |
253 | struct pgpath *pgpath; | |
4e2d19e4 | 254 | unsigned long pg_init_delay = 0; |
fb612642 | 255 | |
17f4ff45 | 256 | if (m->pg_init_in_progress || m->pg_init_disabled) |
3e9f1be1 | 257 | return 0; |
17f4ff45 | 258 | |
fb612642 KU |
259 | m->pg_init_count++; |
260 | m->pg_init_required = 0; | |
3e9f1be1 HR |
261 | |
262 | /* Check here to reset pg_init_required */ | |
263 | if (!m->current_pg) | |
264 | return 0; | |
265 | ||
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 | } | |
3e9f1be1 | 277 | return m->pg_init_in_progress; |
fb612642 KU |
278 | } |
279 | ||
1da177e4 LT |
280 | static void __switch_pg(struct multipath *m, struct pgpath *pgpath) |
281 | { | |
1da177e4 LT |
282 | m->current_pg = pgpath->pg; |
283 | ||
284 | /* Must we initialise the PG first, and queue I/O till it's ready? */ | |
cfae5c9b | 285 | if (m->hw_handler_name) { |
1da177e4 LT |
286 | m->pg_init_required = 1; |
287 | m->queue_io = 1; | |
288 | } else { | |
289 | m->pg_init_required = 0; | |
290 | m->queue_io = 0; | |
291 | } | |
c9e45581 DW |
292 | |
293 | m->pg_init_count = 0; | |
1da177e4 LT |
294 | } |
295 | ||
02ab823f KU |
296 | static int __choose_path_in_pg(struct multipath *m, struct priority_group *pg, |
297 | size_t nr_bytes) | |
1da177e4 | 298 | { |
c922d5f7 | 299 | struct dm_path *path; |
1da177e4 | 300 | |
02ab823f | 301 | path = pg->ps.type->select_path(&pg->ps, &m->repeat_count, nr_bytes); |
1da177e4 LT |
302 | if (!path) |
303 | return -ENXIO; | |
304 | ||
305 | m->current_pgpath = path_to_pgpath(path); | |
306 | ||
307 | if (m->current_pg != pg) | |
308 | __switch_pg(m, m->current_pgpath); | |
309 | ||
310 | return 0; | |
311 | } | |
312 | ||
02ab823f | 313 | static void __choose_pgpath(struct multipath *m, size_t nr_bytes) |
1da177e4 LT |
314 | { |
315 | struct priority_group *pg; | |
316 | unsigned bypassed = 1; | |
317 | ||
1f271972 BM |
318 | if (!m->nr_valid_paths) { |
319 | m->queue_io = 0; | |
1da177e4 | 320 | goto failed; |
1f271972 | 321 | } |
1da177e4 LT |
322 | |
323 | /* Were we instructed to switch PG? */ | |
324 | if (m->next_pg) { | |
325 | pg = m->next_pg; | |
326 | m->next_pg = NULL; | |
02ab823f | 327 | if (!__choose_path_in_pg(m, pg, nr_bytes)) |
1da177e4 LT |
328 | return; |
329 | } | |
330 | ||
331 | /* Don't change PG until it has no remaining paths */ | |
02ab823f | 332 | if (m->current_pg && !__choose_path_in_pg(m, m->current_pg, nr_bytes)) |
1da177e4 LT |
333 | return; |
334 | ||
335 | /* | |
336 | * Loop through priority groups until we find a valid path. | |
337 | * First time we skip PGs marked 'bypassed'. | |
f220fd4e MC |
338 | * Second time we only try the ones we skipped, but set |
339 | * pg_init_delay_retry so we do not hammer controllers. | |
1da177e4 LT |
340 | */ |
341 | do { | |
342 | list_for_each_entry(pg, &m->priority_groups, list) { | |
343 | if (pg->bypassed == bypassed) | |
344 | continue; | |
f220fd4e MC |
345 | if (!__choose_path_in_pg(m, pg, nr_bytes)) { |
346 | if (!bypassed) | |
347 | m->pg_init_delay_retry = 1; | |
1da177e4 | 348 | return; |
f220fd4e | 349 | } |
1da177e4 LT |
350 | } |
351 | } while (bypassed--); | |
352 | ||
353 | failed: | |
354 | m->current_pgpath = NULL; | |
355 | m->current_pg = NULL; | |
356 | } | |
357 | ||
45e15720 KU |
358 | /* |
359 | * Check whether bios must be queued in the device-mapper core rather | |
360 | * than here in the target. | |
361 | * | |
362 | * m->lock must be held on entry. | |
363 | * | |
364 | * If m->queue_if_no_path and m->saved_queue_if_no_path hold the | |
365 | * same value then we are not between multipath_presuspend() | |
366 | * and multipath_resume() calls and we have no need to check | |
367 | * for the DMF_NOFLUSH_SUSPENDING flag. | |
368 | */ | |
369 | static int __must_push_back(struct multipath *m) | |
370 | { | |
e8099177 HR |
371 | return (m->queue_if_no_path || |
372 | (m->queue_if_no_path != m->saved_queue_if_no_path && | |
373 | dm_noflush_suspending(m->ti))); | |
45e15720 KU |
374 | } |
375 | ||
36fcffcc HR |
376 | /* |
377 | * Map cloned requests | |
378 | */ | |
e5863d9a MS |
379 | static int __multipath_map(struct dm_target *ti, struct request *clone, |
380 | union map_info *map_context, | |
381 | struct request *rq, struct request **__clone) | |
1da177e4 | 382 | { |
36fcffcc | 383 | struct multipath *m = (struct multipath *) ti->private; |
e3bde04f | 384 | int r = DM_MAPIO_REQUEUE; |
e5863d9a | 385 | size_t nr_bytes = clone ? blk_rq_bytes(clone) : blk_rq_bytes(rq); |
1da177e4 | 386 | struct pgpath *pgpath; |
f40c67f0 | 387 | struct block_device *bdev; |
e3bde04f | 388 | struct dm_mpath_io *mpio; |
1da177e4 | 389 | |
2eb6e1e3 | 390 | spin_lock_irq(&m->lock); |
1da177e4 LT |
391 | |
392 | /* Do we need to select a new pgpath? */ | |
393 | if (!m->current_pgpath || | |
394 | (!m->queue_io && (m->repeat_count && --m->repeat_count == 0))) | |
02ab823f | 395 | __choose_pgpath(m, nr_bytes); |
1da177e4 LT |
396 | |
397 | pgpath = m->current_pgpath; | |
398 | ||
9bf59a61 MS |
399 | if (!pgpath) { |
400 | if (!__must_push_back(m)) | |
401 | r = -EIO; /* Failed */ | |
402 | goto out_unlock; | |
6afbc01d | 403 | } else if (m->queue_io || m->pg_init_required) { |
e3bde04f | 404 | __pg_init_all_paths(m); |
9bf59a61 MS |
405 | goto out_unlock; |
406 | } | |
6afbc01d | 407 | |
9bf59a61 MS |
408 | if (set_mapinfo(m, map_context) < 0) |
409 | /* ENOMEM, requeue */ | |
410 | goto out_unlock; | |
411 | ||
2eb6e1e3 KB |
412 | mpio = map_context->ptr; |
413 | mpio->pgpath = pgpath; | |
414 | mpio->nr_bytes = nr_bytes; | |
415 | ||
9bf59a61 | 416 | bdev = pgpath->path.dev->bdev; |
2eb6e1e3 | 417 | |
2eb6e1e3 KB |
418 | spin_unlock_irq(&m->lock); |
419 | ||
e5863d9a MS |
420 | if (clone) { |
421 | /* Old request-based interface: allocated clone is passed in */ | |
422 | clone->q = bdev_get_queue(bdev); | |
423 | clone->rq_disk = bdev->bd_disk; | |
424 | clone->cmd_flags |= REQ_FAILFAST_TRANSPORT; | |
425 | } else { | |
426 | /* blk-mq request-based interface */ | |
427 | *__clone = blk_get_request(bdev_get_queue(bdev), | |
02233342 | 428 | rq_data_dir(rq), GFP_ATOMIC); |
4c6dd53d | 429 | if (IS_ERR(*__clone)) { |
e5863d9a | 430 | /* ENOMEM, requeue */ |
4c6dd53d | 431 | clear_mapinfo(m, map_context); |
e5863d9a | 432 | return r; |
4c6dd53d | 433 | } |
e5863d9a MS |
434 | (*__clone)->bio = (*__clone)->biotail = NULL; |
435 | (*__clone)->rq_disk = bdev->bd_disk; | |
436 | (*__clone)->cmd_flags |= REQ_FAILFAST_TRANSPORT; | |
437 | } | |
438 | ||
9bf59a61 MS |
439 | if (pgpath->pg->ps.type->start_io) |
440 | pgpath->pg->ps.type->start_io(&pgpath->pg->ps, | |
441 | &pgpath->path, | |
442 | nr_bytes); | |
2eb6e1e3 | 443 | return DM_MAPIO_REMAPPED; |
1da177e4 | 444 | |
e3bde04f | 445 | out_unlock: |
2eb6e1e3 | 446 | spin_unlock_irq(&m->lock); |
1da177e4 LT |
447 | |
448 | return r; | |
449 | } | |
450 | ||
e5863d9a MS |
451 | static int multipath_map(struct dm_target *ti, struct request *clone, |
452 | union map_info *map_context) | |
453 | { | |
454 | return __multipath_map(ti, clone, map_context, NULL, NULL); | |
455 | } | |
456 | ||
457 | static int multipath_clone_and_map(struct dm_target *ti, struct request *rq, | |
458 | union map_info *map_context, | |
459 | struct request **clone) | |
460 | { | |
461 | return __multipath_map(ti, NULL, map_context, rq, clone); | |
462 | } | |
463 | ||
464 | static void multipath_release_clone(struct request *clone) | |
465 | { | |
466 | blk_put_request(clone); | |
467 | } | |
468 | ||
1da177e4 LT |
469 | /* |
470 | * If we run out of usable paths, should we queue I/O or error it? | |
471 | */ | |
485ef69e AK |
472 | static int queue_if_no_path(struct multipath *m, unsigned queue_if_no_path, |
473 | unsigned save_old_value) | |
1da177e4 LT |
474 | { |
475 | unsigned long flags; | |
476 | ||
477 | spin_lock_irqsave(&m->lock, flags); | |
478 | ||
485ef69e AK |
479 | if (save_old_value) |
480 | m->saved_queue_if_no_path = m->queue_if_no_path; | |
481 | else | |
482 | m->saved_queue_if_no_path = queue_if_no_path; | |
1da177e4 | 483 | m->queue_if_no_path = queue_if_no_path; |
1da177e4 LT |
484 | spin_unlock_irqrestore(&m->lock, flags); |
485 | ||
63d832c3 HR |
486 | if (!queue_if_no_path) |
487 | dm_table_run_md_queue_async(m->ti->table); | |
488 | ||
1da177e4 LT |
489 | return 0; |
490 | } | |
491 | ||
1da177e4 LT |
492 | /* |
493 | * An event is triggered whenever a path is taken out of use. | |
494 | * Includes path failure and PG bypass. | |
495 | */ | |
c4028958 | 496 | static void trigger_event(struct work_struct *work) |
1da177e4 | 497 | { |
c4028958 DH |
498 | struct multipath *m = |
499 | container_of(work, struct multipath, trigger_event); | |
1da177e4 LT |
500 | |
501 | dm_table_event(m->ti->table); | |
502 | } | |
503 | ||
504 | /*----------------------------------------------------------------- | |
505 | * Constructor/argument parsing: | |
506 | * <#multipath feature args> [<arg>]* | |
507 | * <#hw_handler args> [hw_handler [<arg>]*] | |
508 | * <#priority groups> | |
509 | * <initial priority group> | |
510 | * [<selector> <#selector args> [<arg>]* | |
511 | * <#paths> <#per-path selector args> | |
512 | * [<path> [<arg>]* ]+ ]+ | |
513 | *---------------------------------------------------------------*/ | |
498f0103 | 514 | static int parse_path_selector(struct dm_arg_set *as, struct priority_group *pg, |
1da177e4 LT |
515 | struct dm_target *ti) |
516 | { | |
517 | int r; | |
518 | struct path_selector_type *pst; | |
519 | unsigned ps_argc; | |
520 | ||
498f0103 | 521 | static struct dm_arg _args[] = { |
72d94861 | 522 | {0, 1024, "invalid number of path selector args"}, |
1da177e4 LT |
523 | }; |
524 | ||
498f0103 | 525 | pst = dm_get_path_selector(dm_shift_arg(as)); |
1da177e4 | 526 | if (!pst) { |
72d94861 | 527 | ti->error = "unknown path selector type"; |
1da177e4 LT |
528 | return -EINVAL; |
529 | } | |
530 | ||
498f0103 | 531 | r = dm_read_arg_group(_args, as, &ps_argc, &ti->error); |
371b2e34 MP |
532 | if (r) { |
533 | dm_put_path_selector(pst); | |
1da177e4 | 534 | return -EINVAL; |
371b2e34 | 535 | } |
1da177e4 LT |
536 | |
537 | r = pst->create(&pg->ps, ps_argc, as->argv); | |
538 | if (r) { | |
539 | dm_put_path_selector(pst); | |
72d94861 | 540 | ti->error = "path selector constructor failed"; |
1da177e4 LT |
541 | return r; |
542 | } | |
543 | ||
544 | pg->ps.type = pst; | |
498f0103 | 545 | dm_consume_args(as, ps_argc); |
1da177e4 LT |
546 | |
547 | return 0; | |
548 | } | |
549 | ||
498f0103 | 550 | static struct pgpath *parse_path(struct dm_arg_set *as, struct path_selector *ps, |
1da177e4 LT |
551 | struct dm_target *ti) |
552 | { | |
553 | int r; | |
554 | struct pgpath *p; | |
ae11b1b3 | 555 | struct multipath *m = ti->private; |
a58a935d MS |
556 | struct request_queue *q = NULL; |
557 | const char *attached_handler_name; | |
1da177e4 LT |
558 | |
559 | /* we need at least a path arg */ | |
560 | if (as->argc < 1) { | |
72d94861 | 561 | ti->error = "no device given"; |
01460f35 | 562 | return ERR_PTR(-EINVAL); |
1da177e4 LT |
563 | } |
564 | ||
565 | p = alloc_pgpath(); | |
566 | if (!p) | |
01460f35 | 567 | return ERR_PTR(-ENOMEM); |
1da177e4 | 568 | |
498f0103 | 569 | r = dm_get_device(ti, dm_shift_arg(as), dm_table_get_mode(ti->table), |
8215d6ec | 570 | &p->path.dev); |
1da177e4 | 571 | if (r) { |
72d94861 | 572 | ti->error = "error getting device"; |
1da177e4 LT |
573 | goto bad; |
574 | } | |
575 | ||
a58a935d MS |
576 | if (m->retain_attached_hw_handler || m->hw_handler_name) |
577 | q = bdev_get_queue(p->path.dev->bdev); | |
578 | ||
579 | if (m->retain_attached_hw_handler) { | |
1bab0de0 | 580 | retain: |
a58a935d MS |
581 | attached_handler_name = scsi_dh_attached_handler_name(q, GFP_KERNEL); |
582 | if (attached_handler_name) { | |
583 | /* | |
584 | * Reset hw_handler_name to match the attached handler | |
585 | * and clear any hw_handler_params associated with the | |
586 | * ignored handler. | |
587 | * | |
588 | * NB. This modifies the table line to show the actual | |
589 | * handler instead of the original table passed in. | |
590 | */ | |
591 | kfree(m->hw_handler_name); | |
592 | m->hw_handler_name = attached_handler_name; | |
593 | ||
594 | kfree(m->hw_handler_params); | |
595 | m->hw_handler_params = NULL; | |
596 | } | |
597 | } | |
a0cf7ea9 | 598 | |
a58a935d | 599 | if (m->hw_handler_name) { |
a0cf7ea9 HR |
600 | r = scsi_dh_attach(q, m->hw_handler_name); |
601 | if (r == -EBUSY) { | |
1bab0de0 | 602 | char b[BDEVNAME_SIZE]; |
a0cf7ea9 | 603 | |
1bab0de0 CH |
604 | printk(KERN_INFO "dm-mpath: retaining handler on device %s\n", |
605 | bdevname(p->path.dev->bdev, b)); | |
606 | goto retain; | |
607 | } | |
ae11b1b3 | 608 | if (r < 0) { |
a0cf7ea9 | 609 | ti->error = "error attaching hardware handler"; |
ae11b1b3 HR |
610 | dm_put_device(ti, p->path.dev); |
611 | goto bad; | |
612 | } | |
2bfd2e13 CS |
613 | |
614 | if (m->hw_handler_params) { | |
615 | r = scsi_dh_set_params(q, m->hw_handler_params); | |
616 | if (r < 0) { | |
617 | ti->error = "unable to set hardware " | |
618 | "handler parameters"; | |
2bfd2e13 CS |
619 | dm_put_device(ti, p->path.dev); |
620 | goto bad; | |
621 | } | |
622 | } | |
ae11b1b3 HR |
623 | } |
624 | ||
1da177e4 LT |
625 | r = ps->type->add_path(ps, &p->path, as->argc, as->argv, &ti->error); |
626 | if (r) { | |
627 | dm_put_device(ti, p->path.dev); | |
628 | goto bad; | |
629 | } | |
630 | ||
631 | return p; | |
632 | ||
633 | bad: | |
634 | free_pgpath(p); | |
01460f35 | 635 | return ERR_PTR(r); |
1da177e4 LT |
636 | } |
637 | ||
498f0103 | 638 | static struct priority_group *parse_priority_group(struct dm_arg_set *as, |
28f16c20 | 639 | struct multipath *m) |
1da177e4 | 640 | { |
498f0103 | 641 | static struct dm_arg _args[] = { |
72d94861 AK |
642 | {1, 1024, "invalid number of paths"}, |
643 | {0, 1024, "invalid number of selector args"} | |
1da177e4 LT |
644 | }; |
645 | ||
646 | int r; | |
498f0103 | 647 | unsigned i, nr_selector_args, nr_args; |
1da177e4 | 648 | struct priority_group *pg; |
28f16c20 | 649 | struct dm_target *ti = m->ti; |
1da177e4 LT |
650 | |
651 | if (as->argc < 2) { | |
652 | as->argc = 0; | |
01460f35 BM |
653 | ti->error = "not enough priority group arguments"; |
654 | return ERR_PTR(-EINVAL); | |
1da177e4 LT |
655 | } |
656 | ||
657 | pg = alloc_priority_group(); | |
658 | if (!pg) { | |
72d94861 | 659 | ti->error = "couldn't allocate priority group"; |
01460f35 | 660 | return ERR_PTR(-ENOMEM); |
1da177e4 LT |
661 | } |
662 | pg->m = m; | |
663 | ||
664 | r = parse_path_selector(as, pg, ti); | |
665 | if (r) | |
666 | goto bad; | |
667 | ||
668 | /* | |
669 | * read the paths | |
670 | */ | |
498f0103 | 671 | r = dm_read_arg(_args, as, &pg->nr_pgpaths, &ti->error); |
1da177e4 LT |
672 | if (r) |
673 | goto bad; | |
674 | ||
498f0103 | 675 | r = dm_read_arg(_args + 1, as, &nr_selector_args, &ti->error); |
1da177e4 LT |
676 | if (r) |
677 | goto bad; | |
678 | ||
498f0103 | 679 | nr_args = 1 + nr_selector_args; |
1da177e4 LT |
680 | for (i = 0; i < pg->nr_pgpaths; i++) { |
681 | struct pgpath *pgpath; | |
498f0103 | 682 | struct dm_arg_set path_args; |
1da177e4 | 683 | |
498f0103 | 684 | if (as->argc < nr_args) { |
148acff6 | 685 | ti->error = "not enough path parameters"; |
6bbf79a1 | 686 | r = -EINVAL; |
1da177e4 | 687 | goto bad; |
148acff6 | 688 | } |
1da177e4 | 689 | |
498f0103 | 690 | path_args.argc = nr_args; |
1da177e4 LT |
691 | path_args.argv = as->argv; |
692 | ||
693 | pgpath = parse_path(&path_args, &pg->ps, ti); | |
01460f35 BM |
694 | if (IS_ERR(pgpath)) { |
695 | r = PTR_ERR(pgpath); | |
1da177e4 | 696 | goto bad; |
01460f35 | 697 | } |
1da177e4 LT |
698 | |
699 | pgpath->pg = pg; | |
700 | list_add_tail(&pgpath->list, &pg->pgpaths); | |
498f0103 | 701 | dm_consume_args(as, nr_args); |
1da177e4 LT |
702 | } |
703 | ||
704 | return pg; | |
705 | ||
706 | bad: | |
707 | free_priority_group(pg, ti); | |
01460f35 | 708 | return ERR_PTR(r); |
1da177e4 LT |
709 | } |
710 | ||
498f0103 | 711 | static int parse_hw_handler(struct dm_arg_set *as, struct multipath *m) |
1da177e4 | 712 | { |
1da177e4 | 713 | unsigned hw_argc; |
2bfd2e13 | 714 | int ret; |
28f16c20 | 715 | struct dm_target *ti = m->ti; |
1da177e4 | 716 | |
498f0103 | 717 | static struct dm_arg _args[] = { |
72d94861 | 718 | {0, 1024, "invalid number of hardware handler args"}, |
1da177e4 LT |
719 | }; |
720 | ||
498f0103 | 721 | if (dm_read_arg_group(_args, as, &hw_argc, &ti->error)) |
1da177e4 LT |
722 | return -EINVAL; |
723 | ||
724 | if (!hw_argc) | |
725 | return 0; | |
726 | ||
498f0103 | 727 | m->hw_handler_name = kstrdup(dm_shift_arg(as), GFP_KERNEL); |
14e98c5c | 728 | |
2bfd2e13 CS |
729 | if (hw_argc > 1) { |
730 | char *p; | |
731 | int i, j, len = 4; | |
732 | ||
733 | for (i = 0; i <= hw_argc - 2; i++) | |
734 | len += strlen(as->argv[i]) + 1; | |
735 | p = m->hw_handler_params = kzalloc(len, GFP_KERNEL); | |
736 | if (!p) { | |
737 | ti->error = "memory allocation failed"; | |
738 | ret = -ENOMEM; | |
739 | goto fail; | |
740 | } | |
741 | j = sprintf(p, "%d", hw_argc - 1); | |
742 | for (i = 0, p+=j+1; i <= hw_argc - 2; i++, p+=j+1) | |
743 | j = sprintf(p, "%s", as->argv[i]); | |
744 | } | |
498f0103 | 745 | dm_consume_args(as, hw_argc - 1); |
1da177e4 LT |
746 | |
747 | return 0; | |
2bfd2e13 CS |
748 | fail: |
749 | kfree(m->hw_handler_name); | |
750 | m->hw_handler_name = NULL; | |
751 | return ret; | |
1da177e4 LT |
752 | } |
753 | ||
498f0103 | 754 | static int parse_features(struct dm_arg_set *as, struct multipath *m) |
1da177e4 LT |
755 | { |
756 | int r; | |
757 | unsigned argc; | |
28f16c20 | 758 | struct dm_target *ti = m->ti; |
498f0103 | 759 | const char *arg_name; |
1da177e4 | 760 | |
498f0103 | 761 | static struct dm_arg _args[] = { |
a58a935d | 762 | {0, 6, "invalid number of feature args"}, |
c9e45581 | 763 | {1, 50, "pg_init_retries must be between 1 and 50"}, |
4e2d19e4 | 764 | {0, 60000, "pg_init_delay_msecs must be between 0 and 60000"}, |
1da177e4 LT |
765 | }; |
766 | ||
498f0103 | 767 | r = dm_read_arg_group(_args, as, &argc, &ti->error); |
1da177e4 LT |
768 | if (r) |
769 | return -EINVAL; | |
770 | ||
771 | if (!argc) | |
772 | return 0; | |
773 | ||
c9e45581 | 774 | do { |
498f0103 | 775 | arg_name = dm_shift_arg(as); |
c9e45581 DW |
776 | argc--; |
777 | ||
498f0103 | 778 | if (!strcasecmp(arg_name, "queue_if_no_path")) { |
c9e45581 DW |
779 | r = queue_if_no_path(m, 1, 0); |
780 | continue; | |
781 | } | |
782 | ||
a58a935d MS |
783 | if (!strcasecmp(arg_name, "retain_attached_hw_handler")) { |
784 | m->retain_attached_hw_handler = 1; | |
785 | continue; | |
786 | } | |
787 | ||
498f0103 | 788 | if (!strcasecmp(arg_name, "pg_init_retries") && |
c9e45581 | 789 | (argc >= 1)) { |
498f0103 | 790 | r = dm_read_arg(_args + 1, as, &m->pg_init_retries, &ti->error); |
c9e45581 DW |
791 | argc--; |
792 | continue; | |
793 | } | |
794 | ||
498f0103 | 795 | if (!strcasecmp(arg_name, "pg_init_delay_msecs") && |
4e2d19e4 | 796 | (argc >= 1)) { |
498f0103 | 797 | r = dm_read_arg(_args + 2, as, &m->pg_init_delay_msecs, &ti->error); |
4e2d19e4 CS |
798 | argc--; |
799 | continue; | |
800 | } | |
801 | ||
1da177e4 | 802 | ti->error = "Unrecognised multipath feature request"; |
c9e45581 DW |
803 | r = -EINVAL; |
804 | } while (argc && !r); | |
805 | ||
806 | return r; | |
1da177e4 LT |
807 | } |
808 | ||
809 | static int multipath_ctr(struct dm_target *ti, unsigned int argc, | |
810 | char **argv) | |
811 | { | |
498f0103 MS |
812 | /* target arguments */ |
813 | static struct dm_arg _args[] = { | |
a490a07a MS |
814 | {0, 1024, "invalid number of priority groups"}, |
815 | {0, 1024, "invalid initial priority group number"}, | |
1da177e4 LT |
816 | }; |
817 | ||
818 | int r; | |
819 | struct multipath *m; | |
498f0103 | 820 | struct dm_arg_set as; |
1da177e4 LT |
821 | unsigned pg_count = 0; |
822 | unsigned next_pg_num; | |
823 | ||
824 | as.argc = argc; | |
825 | as.argv = argv; | |
826 | ||
28f16c20 | 827 | m = alloc_multipath(ti); |
1da177e4 | 828 | if (!m) { |
72d94861 | 829 | ti->error = "can't allocate multipath"; |
1da177e4 LT |
830 | return -EINVAL; |
831 | } | |
832 | ||
28f16c20 | 833 | r = parse_features(&as, m); |
1da177e4 LT |
834 | if (r) |
835 | goto bad; | |
836 | ||
28f16c20 | 837 | r = parse_hw_handler(&as, m); |
1da177e4 LT |
838 | if (r) |
839 | goto bad; | |
840 | ||
498f0103 | 841 | r = dm_read_arg(_args, &as, &m->nr_priority_groups, &ti->error); |
1da177e4 LT |
842 | if (r) |
843 | goto bad; | |
844 | ||
498f0103 | 845 | r = dm_read_arg(_args + 1, &as, &next_pg_num, &ti->error); |
1da177e4 LT |
846 | if (r) |
847 | goto bad; | |
848 | ||
a490a07a MS |
849 | if ((!m->nr_priority_groups && next_pg_num) || |
850 | (m->nr_priority_groups && !next_pg_num)) { | |
851 | ti->error = "invalid initial priority group"; | |
852 | r = -EINVAL; | |
853 | goto bad; | |
854 | } | |
855 | ||
1da177e4 LT |
856 | /* parse the priority groups */ |
857 | while (as.argc) { | |
858 | struct priority_group *pg; | |
859 | ||
28f16c20 | 860 | pg = parse_priority_group(&as, m); |
01460f35 BM |
861 | if (IS_ERR(pg)) { |
862 | r = PTR_ERR(pg); | |
1da177e4 LT |
863 | goto bad; |
864 | } | |
865 | ||
866 | m->nr_valid_paths += pg->nr_pgpaths; | |
867 | list_add_tail(&pg->list, &m->priority_groups); | |
868 | pg_count++; | |
869 | pg->pg_num = pg_count; | |
870 | if (!--next_pg_num) | |
871 | m->next_pg = pg; | |
872 | } | |
873 | ||
874 | if (pg_count != m->nr_priority_groups) { | |
72d94861 | 875 | ti->error = "priority group count mismatch"; |
1da177e4 LT |
876 | r = -EINVAL; |
877 | goto bad; | |
878 | } | |
879 | ||
55a62eef AK |
880 | ti->num_flush_bios = 1; |
881 | ti->num_discard_bios = 1; | |
042bcef8 | 882 | ti->num_write_same_bios = 1; |
8627921f | 883 | |
1da177e4 LT |
884 | return 0; |
885 | ||
886 | bad: | |
887 | free_multipath(m); | |
888 | return r; | |
889 | } | |
890 | ||
2bded7bd KU |
891 | static void multipath_wait_for_pg_init_completion(struct multipath *m) |
892 | { | |
893 | DECLARE_WAITQUEUE(wait, current); | |
894 | unsigned long flags; | |
895 | ||
896 | add_wait_queue(&m->pg_init_wait, &wait); | |
897 | ||
898 | while (1) { | |
899 | set_current_state(TASK_UNINTERRUPTIBLE); | |
900 | ||
901 | spin_lock_irqsave(&m->lock, flags); | |
902 | if (!m->pg_init_in_progress) { | |
903 | spin_unlock_irqrestore(&m->lock, flags); | |
904 | break; | |
905 | } | |
906 | spin_unlock_irqrestore(&m->lock, flags); | |
907 | ||
908 | io_schedule(); | |
909 | } | |
910 | set_current_state(TASK_RUNNING); | |
911 | ||
912 | remove_wait_queue(&m->pg_init_wait, &wait); | |
913 | } | |
914 | ||
915 | static void flush_multipath_work(struct multipath *m) | |
1da177e4 | 916 | { |
954a73d5 SKM |
917 | unsigned long flags; |
918 | ||
919 | spin_lock_irqsave(&m->lock, flags); | |
920 | m->pg_init_disabled = 1; | |
921 | spin_unlock_irqrestore(&m->lock, flags); | |
922 | ||
bab7cfc7 | 923 | flush_workqueue(kmpath_handlerd); |
2bded7bd | 924 | multipath_wait_for_pg_init_completion(m); |
a044d016 | 925 | flush_workqueue(kmultipathd); |
43829731 | 926 | flush_work(&m->trigger_event); |
954a73d5 SKM |
927 | |
928 | spin_lock_irqsave(&m->lock, flags); | |
929 | m->pg_init_disabled = 0; | |
930 | spin_unlock_irqrestore(&m->lock, flags); | |
6df400ab KU |
931 | } |
932 | ||
933 | static void multipath_dtr(struct dm_target *ti) | |
934 | { | |
935 | struct multipath *m = ti->private; | |
936 | ||
2bded7bd | 937 | flush_multipath_work(m); |
1da177e4 LT |
938 | free_multipath(m); |
939 | } | |
940 | ||
1da177e4 LT |
941 | /* |
942 | * Take a path out of use. | |
943 | */ | |
944 | static int fail_path(struct pgpath *pgpath) | |
945 | { | |
946 | unsigned long flags; | |
947 | struct multipath *m = pgpath->pg->m; | |
948 | ||
949 | spin_lock_irqsave(&m->lock, flags); | |
950 | ||
6680073d | 951 | if (!pgpath->is_active) |
1da177e4 LT |
952 | goto out; |
953 | ||
72d94861 | 954 | DMWARN("Failing path %s.", pgpath->path.dev->name); |
1da177e4 LT |
955 | |
956 | pgpath->pg->ps.type->fail_path(&pgpath->pg->ps, &pgpath->path); | |
6680073d | 957 | pgpath->is_active = 0; |
1da177e4 LT |
958 | pgpath->fail_count++; |
959 | ||
960 | m->nr_valid_paths--; | |
961 | ||
962 | if (pgpath == m->current_pgpath) | |
963 | m->current_pgpath = NULL; | |
964 | ||
b15546f9 MA |
965 | dm_path_uevent(DM_UEVENT_PATH_FAILED, m->ti, |
966 | pgpath->path.dev->name, m->nr_valid_paths); | |
967 | ||
fe9cf30e | 968 | schedule_work(&m->trigger_event); |
1da177e4 LT |
969 | |
970 | out: | |
971 | spin_unlock_irqrestore(&m->lock, flags); | |
972 | ||
973 | return 0; | |
974 | } | |
975 | ||
976 | /* | |
977 | * Reinstate a previously-failed path | |
978 | */ | |
979 | static int reinstate_path(struct pgpath *pgpath) | |
980 | { | |
63d832c3 | 981 | int r = 0, run_queue = 0; |
1da177e4 LT |
982 | unsigned long flags; |
983 | struct multipath *m = pgpath->pg->m; | |
984 | ||
985 | spin_lock_irqsave(&m->lock, flags); | |
986 | ||
6680073d | 987 | if (pgpath->is_active) |
1da177e4 LT |
988 | goto out; |
989 | ||
def052d2 | 990 | if (!pgpath->pg->ps.type->reinstate_path) { |
1da177e4 LT |
991 | DMWARN("Reinstate path not supported by path selector %s", |
992 | pgpath->pg->ps.type->name); | |
993 | r = -EINVAL; | |
994 | goto out; | |
995 | } | |
996 | ||
997 | r = pgpath->pg->ps.type->reinstate_path(&pgpath->pg->ps, &pgpath->path); | |
998 | if (r) | |
999 | goto out; | |
1000 | ||
6680073d | 1001 | pgpath->is_active = 1; |
1da177e4 | 1002 | |
e8099177 | 1003 | if (!m->nr_valid_paths++) { |
e54f77dd | 1004 | m->current_pgpath = NULL; |
63d832c3 | 1005 | run_queue = 1; |
e54f77dd | 1006 | } else if (m->hw_handler_name && (m->current_pg == pgpath->pg)) { |
4e2d19e4 | 1007 | if (queue_work(kmpath_handlerd, &pgpath->activate_path.work)) |
e54f77dd CS |
1008 | m->pg_init_in_progress++; |
1009 | } | |
1da177e4 | 1010 | |
b15546f9 MA |
1011 | dm_path_uevent(DM_UEVENT_PATH_REINSTATED, m->ti, |
1012 | pgpath->path.dev->name, m->nr_valid_paths); | |
1013 | ||
fe9cf30e | 1014 | schedule_work(&m->trigger_event); |
1da177e4 LT |
1015 | |
1016 | out: | |
1017 | spin_unlock_irqrestore(&m->lock, flags); | |
63d832c3 HR |
1018 | if (run_queue) |
1019 | dm_table_run_md_queue_async(m->ti->table); | |
1da177e4 LT |
1020 | |
1021 | return r; | |
1022 | } | |
1023 | ||
1024 | /* | |
1025 | * Fail or reinstate all paths that match the provided struct dm_dev. | |
1026 | */ | |
1027 | static int action_dev(struct multipath *m, struct dm_dev *dev, | |
1028 | action_fn action) | |
1029 | { | |
19040c0b | 1030 | int r = -EINVAL; |
1da177e4 LT |
1031 | struct pgpath *pgpath; |
1032 | struct priority_group *pg; | |
1033 | ||
1034 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1035 | list_for_each_entry(pgpath, &pg->pgpaths, list) { | |
1036 | if (pgpath->path.dev == dev) | |
1037 | r = action(pgpath); | |
1038 | } | |
1039 | } | |
1040 | ||
1041 | return r; | |
1042 | } | |
1043 | ||
1044 | /* | |
1045 | * Temporarily try to avoid having to use the specified PG | |
1046 | */ | |
1047 | static void bypass_pg(struct multipath *m, struct priority_group *pg, | |
1048 | int bypassed) | |
1049 | { | |
1050 | unsigned long flags; | |
1051 | ||
1052 | spin_lock_irqsave(&m->lock, flags); | |
1053 | ||
1054 | pg->bypassed = bypassed; | |
1055 | m->current_pgpath = NULL; | |
1056 | m->current_pg = NULL; | |
1057 | ||
1058 | spin_unlock_irqrestore(&m->lock, flags); | |
1059 | ||
fe9cf30e | 1060 | schedule_work(&m->trigger_event); |
1da177e4 LT |
1061 | } |
1062 | ||
1063 | /* | |
1064 | * Switch to using the specified PG from the next I/O that gets mapped | |
1065 | */ | |
1066 | static int switch_pg_num(struct multipath *m, const char *pgstr) | |
1067 | { | |
1068 | struct priority_group *pg; | |
1069 | unsigned pgnum; | |
1070 | unsigned long flags; | |
31998ef1 | 1071 | char dummy; |
1da177e4 | 1072 | |
31998ef1 | 1073 | if (!pgstr || (sscanf(pgstr, "%u%c", &pgnum, &dummy) != 1) || !pgnum || |
1da177e4 LT |
1074 | (pgnum > m->nr_priority_groups)) { |
1075 | DMWARN("invalid PG number supplied to switch_pg_num"); | |
1076 | return -EINVAL; | |
1077 | } | |
1078 | ||
1079 | spin_lock_irqsave(&m->lock, flags); | |
1080 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1081 | pg->bypassed = 0; | |
1082 | if (--pgnum) | |
1083 | continue; | |
1084 | ||
1085 | m->current_pgpath = NULL; | |
1086 | m->current_pg = NULL; | |
1087 | m->next_pg = pg; | |
1088 | } | |
1089 | spin_unlock_irqrestore(&m->lock, flags); | |
1090 | ||
fe9cf30e | 1091 | schedule_work(&m->trigger_event); |
1da177e4 LT |
1092 | return 0; |
1093 | } | |
1094 | ||
1095 | /* | |
1096 | * Set/clear bypassed status of a PG. | |
1097 | * PGs are numbered upwards from 1 in the order they were declared. | |
1098 | */ | |
1099 | static int bypass_pg_num(struct multipath *m, const char *pgstr, int bypassed) | |
1100 | { | |
1101 | struct priority_group *pg; | |
1102 | unsigned pgnum; | |
31998ef1 | 1103 | char dummy; |
1da177e4 | 1104 | |
31998ef1 | 1105 | if (!pgstr || (sscanf(pgstr, "%u%c", &pgnum, &dummy) != 1) || !pgnum || |
1da177e4 LT |
1106 | (pgnum > m->nr_priority_groups)) { |
1107 | DMWARN("invalid PG number supplied to bypass_pg"); | |
1108 | return -EINVAL; | |
1109 | } | |
1110 | ||
1111 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1112 | if (!--pgnum) | |
1113 | break; | |
1114 | } | |
1115 | ||
1116 | bypass_pg(m, pg, bypassed); | |
1117 | return 0; | |
1118 | } | |
1119 | ||
c9e45581 DW |
1120 | /* |
1121 | * Should we retry pg_init immediately? | |
1122 | */ | |
1123 | static int pg_init_limit_reached(struct multipath *m, struct pgpath *pgpath) | |
1124 | { | |
1125 | unsigned long flags; | |
1126 | int limit_reached = 0; | |
1127 | ||
1128 | spin_lock_irqsave(&m->lock, flags); | |
1129 | ||
954a73d5 | 1130 | if (m->pg_init_count <= m->pg_init_retries && !m->pg_init_disabled) |
c9e45581 DW |
1131 | m->pg_init_required = 1; |
1132 | else | |
1133 | limit_reached = 1; | |
1134 | ||
1135 | spin_unlock_irqrestore(&m->lock, flags); | |
1136 | ||
1137 | return limit_reached; | |
1138 | } | |
1139 | ||
3ae31f6a | 1140 | static void pg_init_done(void *data, int errors) |
cfae5c9b | 1141 | { |
83c0d5d5 | 1142 | struct pgpath *pgpath = data; |
cfae5c9b CS |
1143 | struct priority_group *pg = pgpath->pg; |
1144 | struct multipath *m = pg->m; | |
1145 | unsigned long flags; | |
4e2d19e4 | 1146 | unsigned delay_retry = 0; |
cfae5c9b CS |
1147 | |
1148 | /* device or driver problems */ | |
1149 | switch (errors) { | |
1150 | case SCSI_DH_OK: | |
1151 | break; | |
1152 | case SCSI_DH_NOSYS: | |
1153 | if (!m->hw_handler_name) { | |
1154 | errors = 0; | |
1155 | break; | |
1156 | } | |
f7b934c8 MB |
1157 | DMERR("Could not failover the device: Handler scsi_dh_%s " |
1158 | "Error %d.", m->hw_handler_name, errors); | |
cfae5c9b CS |
1159 | /* |
1160 | * Fail path for now, so we do not ping pong | |
1161 | */ | |
1162 | fail_path(pgpath); | |
1163 | break; | |
1164 | case SCSI_DH_DEV_TEMP_BUSY: | |
1165 | /* | |
1166 | * Probably doing something like FW upgrade on the | |
1167 | * controller so try the other pg. | |
1168 | */ | |
1169 | bypass_pg(m, pg, 1); | |
1170 | break; | |
cfae5c9b | 1171 | case SCSI_DH_RETRY: |
4e2d19e4 CS |
1172 | /* Wait before retrying. */ |
1173 | delay_retry = 1; | |
cfae5c9b CS |
1174 | case SCSI_DH_IMM_RETRY: |
1175 | case SCSI_DH_RES_TEMP_UNAVAIL: | |
1176 | if (pg_init_limit_reached(m, pgpath)) | |
1177 | fail_path(pgpath); | |
1178 | errors = 0; | |
1179 | break; | |
1180 | default: | |
1181 | /* | |
1182 | * We probably do not want to fail the path for a device | |
1183 | * error, but this is what the old dm did. In future | |
1184 | * patches we can do more advanced handling. | |
1185 | */ | |
1186 | fail_path(pgpath); | |
1187 | } | |
1188 | ||
1189 | spin_lock_irqsave(&m->lock, flags); | |
1190 | if (errors) { | |
e54f77dd CS |
1191 | if (pgpath == m->current_pgpath) { |
1192 | DMERR("Could not failover device. Error %d.", errors); | |
1193 | m->current_pgpath = NULL; | |
1194 | m->current_pg = NULL; | |
1195 | } | |
d0259bf0 | 1196 | } else if (!m->pg_init_required) |
cfae5c9b | 1197 | pg->bypassed = 0; |
cfae5c9b | 1198 | |
d0259bf0 KU |
1199 | if (--m->pg_init_in_progress) |
1200 | /* Activations of other paths are still on going */ | |
1201 | goto out; | |
1202 | ||
3e9f1be1 HR |
1203 | if (m->pg_init_required) { |
1204 | m->pg_init_delay_retry = delay_retry; | |
1205 | if (__pg_init_all_paths(m)) | |
1206 | goto out; | |
1207 | } | |
1208 | m->queue_io = 0; | |
d0259bf0 | 1209 | |
2bded7bd KU |
1210 | /* |
1211 | * Wake up any thread waiting to suspend. | |
1212 | */ | |
1213 | wake_up(&m->pg_init_wait); | |
1214 | ||
d0259bf0 | 1215 | out: |
cfae5c9b CS |
1216 | spin_unlock_irqrestore(&m->lock, flags); |
1217 | } | |
1218 | ||
bab7cfc7 CS |
1219 | static void activate_path(struct work_struct *work) |
1220 | { | |
e54f77dd | 1221 | struct pgpath *pgpath = |
4e2d19e4 | 1222 | container_of(work, struct pgpath, activate_path.work); |
bab7cfc7 | 1223 | |
3a017509 HR |
1224 | if (pgpath->is_active) |
1225 | scsi_dh_activate(bdev_get_queue(pgpath->path.dev->bdev), | |
1226 | pg_init_done, pgpath); | |
1227 | else | |
1228 | pg_init_done(pgpath, SCSI_DH_DEV_OFFLINED); | |
bab7cfc7 CS |
1229 | } |
1230 | ||
7e782af5 HR |
1231 | static int noretry_error(int error) |
1232 | { | |
1233 | switch (error) { | |
1234 | case -EOPNOTSUPP: | |
1235 | case -EREMOTEIO: | |
1236 | case -EILSEQ: | |
1237 | case -ENODATA: | |
cc9d3c38 | 1238 | case -ENOSPC: |
7e782af5 HR |
1239 | return 1; |
1240 | } | |
1241 | ||
1242 | /* Anything else could be a path failure, so should be retried */ | |
1243 | return 0; | |
1244 | } | |
1245 | ||
1da177e4 LT |
1246 | /* |
1247 | * end_io handling | |
1248 | */ | |
f40c67f0 | 1249 | static int do_end_io(struct multipath *m, struct request *clone, |
028867ac | 1250 | int error, struct dm_mpath_io *mpio) |
1da177e4 | 1251 | { |
f40c67f0 KU |
1252 | /* |
1253 | * We don't queue any clone request inside the multipath target | |
1254 | * during end I/O handling, since those clone requests don't have | |
1255 | * bio clones. If we queue them inside the multipath target, | |
1256 | * we need to make bio clones, that requires memory allocation. | |
1257 | * (See drivers/md/dm.c:end_clone_bio() about why the clone requests | |
1258 | * don't have bio clones.) | |
1259 | * Instead of queueing the clone request here, we queue the original | |
1260 | * request into dm core, which will remake a clone request and | |
1261 | * clone bios for it and resubmit it later. | |
1262 | */ | |
1263 | int r = DM_ENDIO_REQUEUE; | |
640eb3b0 | 1264 | unsigned long flags; |
1da177e4 | 1265 | |
f40c67f0 | 1266 | if (!error && !clone->errors) |
1da177e4 LT |
1267 | return 0; /* I/O complete */ |
1268 | ||
7eee4ae2 | 1269 | if (noretry_error(error)) |
959eb4e5 MS |
1270 | return error; |
1271 | ||
cfae5c9b CS |
1272 | if (mpio->pgpath) |
1273 | fail_path(mpio->pgpath); | |
1da177e4 | 1274 | |
640eb3b0 | 1275 | spin_lock_irqsave(&m->lock, flags); |
751b2a7d HR |
1276 | if (!m->nr_valid_paths) { |
1277 | if (!m->queue_if_no_path) { | |
1278 | if (!__must_push_back(m)) | |
1279 | r = -EIO; | |
1280 | } else { | |
1281 | if (error == -EBADE) | |
1282 | r = error; | |
1283 | } | |
1284 | } | |
640eb3b0 | 1285 | spin_unlock_irqrestore(&m->lock, flags); |
1da177e4 | 1286 | |
f40c67f0 | 1287 | return r; |
1da177e4 LT |
1288 | } |
1289 | ||
f40c67f0 | 1290 | static int multipath_end_io(struct dm_target *ti, struct request *clone, |
1da177e4 LT |
1291 | int error, union map_info *map_context) |
1292 | { | |
028867ac AK |
1293 | struct multipath *m = ti->private; |
1294 | struct dm_mpath_io *mpio = map_context->ptr; | |
a71a261f | 1295 | struct pgpath *pgpath; |
1da177e4 LT |
1296 | struct path_selector *ps; |
1297 | int r; | |
1298 | ||
466891f9 JN |
1299 | BUG_ON(!mpio); |
1300 | ||
f40c67f0 | 1301 | r = do_end_io(m, clone, error, mpio); |
a71a261f | 1302 | pgpath = mpio->pgpath; |
1da177e4 LT |
1303 | if (pgpath) { |
1304 | ps = &pgpath->pg->ps; | |
1305 | if (ps->type->end_io) | |
02ab823f | 1306 | ps->type->end_io(ps, &pgpath->path, mpio->nr_bytes); |
1da177e4 | 1307 | } |
466891f9 | 1308 | clear_mapinfo(m, map_context); |
1da177e4 LT |
1309 | |
1310 | return r; | |
1311 | } | |
1312 | ||
1313 | /* | |
1314 | * Suspend can't complete until all the I/O is processed so if | |
436d4108 AK |
1315 | * the last path fails we must error any remaining I/O. |
1316 | * Note that if the freeze_bdev fails while suspending, the | |
1317 | * queue_if_no_path state is lost - userspace should reset it. | |
1da177e4 LT |
1318 | */ |
1319 | static void multipath_presuspend(struct dm_target *ti) | |
1320 | { | |
1321 | struct multipath *m = (struct multipath *) ti->private; | |
1da177e4 | 1322 | |
485ef69e | 1323 | queue_if_no_path(m, 0, 1); |
1da177e4 LT |
1324 | } |
1325 | ||
6df400ab KU |
1326 | static void multipath_postsuspend(struct dm_target *ti) |
1327 | { | |
6380f26f MA |
1328 | struct multipath *m = ti->private; |
1329 | ||
1330 | mutex_lock(&m->work_mutex); | |
2bded7bd | 1331 | flush_multipath_work(m); |
6380f26f | 1332 | mutex_unlock(&m->work_mutex); |
6df400ab KU |
1333 | } |
1334 | ||
436d4108 AK |
1335 | /* |
1336 | * Restore the queue_if_no_path setting. | |
1337 | */ | |
1da177e4 LT |
1338 | static void multipath_resume(struct dm_target *ti) |
1339 | { | |
1340 | struct multipath *m = (struct multipath *) ti->private; | |
1341 | unsigned long flags; | |
1342 | ||
1343 | spin_lock_irqsave(&m->lock, flags); | |
436d4108 | 1344 | m->queue_if_no_path = m->saved_queue_if_no_path; |
1da177e4 LT |
1345 | spin_unlock_irqrestore(&m->lock, flags); |
1346 | } | |
1347 | ||
1348 | /* | |
1349 | * Info output has the following format: | |
1350 | * num_multipath_feature_args [multipath_feature_args]* | |
1351 | * num_handler_status_args [handler_status_args]* | |
1352 | * num_groups init_group_number | |
1353 | * [A|D|E num_ps_status_args [ps_status_args]* | |
1354 | * num_paths num_selector_args | |
1355 | * [path_dev A|F fail_count [selector_args]* ]+ ]+ | |
1356 | * | |
1357 | * Table output has the following format (identical to the constructor string): | |
1358 | * num_feature_args [features_args]* | |
1359 | * num_handler_args hw_handler [hw_handler_args]* | |
1360 | * num_groups init_group_number | |
1361 | * [priority selector-name num_ps_args [ps_args]* | |
1362 | * num_paths num_selector_args [path_dev [selector_args]* ]+ ]+ | |
1363 | */ | |
fd7c092e MP |
1364 | static void multipath_status(struct dm_target *ti, status_type_t type, |
1365 | unsigned status_flags, char *result, unsigned maxlen) | |
1da177e4 LT |
1366 | { |
1367 | int sz = 0; | |
1368 | unsigned long flags; | |
1369 | struct multipath *m = (struct multipath *) ti->private; | |
1da177e4 LT |
1370 | struct priority_group *pg; |
1371 | struct pgpath *p; | |
1372 | unsigned pg_num; | |
1373 | char state; | |
1374 | ||
1375 | spin_lock_irqsave(&m->lock, flags); | |
1376 | ||
1377 | /* Features */ | |
1378 | if (type == STATUSTYPE_INFO) | |
e8099177 | 1379 | DMEMIT("2 %u %u ", m->queue_io, m->pg_init_count); |
c9e45581 DW |
1380 | else { |
1381 | DMEMIT("%u ", m->queue_if_no_path + | |
4e2d19e4 | 1382 | (m->pg_init_retries > 0) * 2 + |
a58a935d MS |
1383 | (m->pg_init_delay_msecs != DM_PG_INIT_DELAY_DEFAULT) * 2 + |
1384 | m->retain_attached_hw_handler); | |
c9e45581 DW |
1385 | if (m->queue_if_no_path) |
1386 | DMEMIT("queue_if_no_path "); | |
1387 | if (m->pg_init_retries) | |
1388 | DMEMIT("pg_init_retries %u ", m->pg_init_retries); | |
4e2d19e4 CS |
1389 | if (m->pg_init_delay_msecs != DM_PG_INIT_DELAY_DEFAULT) |
1390 | DMEMIT("pg_init_delay_msecs %u ", m->pg_init_delay_msecs); | |
a58a935d MS |
1391 | if (m->retain_attached_hw_handler) |
1392 | DMEMIT("retain_attached_hw_handler "); | |
c9e45581 | 1393 | } |
1da177e4 | 1394 | |
cfae5c9b | 1395 | if (!m->hw_handler_name || type == STATUSTYPE_INFO) |
1da177e4 LT |
1396 | DMEMIT("0 "); |
1397 | else | |
cfae5c9b | 1398 | DMEMIT("1 %s ", m->hw_handler_name); |
1da177e4 LT |
1399 | |
1400 | DMEMIT("%u ", m->nr_priority_groups); | |
1401 | ||
1402 | if (m->next_pg) | |
1403 | pg_num = m->next_pg->pg_num; | |
1404 | else if (m->current_pg) | |
1405 | pg_num = m->current_pg->pg_num; | |
1406 | else | |
a490a07a | 1407 | pg_num = (m->nr_priority_groups ? 1 : 0); |
1da177e4 LT |
1408 | |
1409 | DMEMIT("%u ", pg_num); | |
1410 | ||
1411 | switch (type) { | |
1412 | case STATUSTYPE_INFO: | |
1413 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1414 | if (pg->bypassed) | |
1415 | state = 'D'; /* Disabled */ | |
1416 | else if (pg == m->current_pg) | |
1417 | state = 'A'; /* Currently Active */ | |
1418 | else | |
1419 | state = 'E'; /* Enabled */ | |
1420 | ||
1421 | DMEMIT("%c ", state); | |
1422 | ||
1423 | if (pg->ps.type->status) | |
1424 | sz += pg->ps.type->status(&pg->ps, NULL, type, | |
1425 | result + sz, | |
1426 | maxlen - sz); | |
1427 | else | |
1428 | DMEMIT("0 "); | |
1429 | ||
1430 | DMEMIT("%u %u ", pg->nr_pgpaths, | |
1431 | pg->ps.type->info_args); | |
1432 | ||
1433 | list_for_each_entry(p, &pg->pgpaths, list) { | |
1434 | DMEMIT("%s %s %u ", p->path.dev->name, | |
6680073d | 1435 | p->is_active ? "A" : "F", |
1da177e4 LT |
1436 | p->fail_count); |
1437 | if (pg->ps.type->status) | |
1438 | sz += pg->ps.type->status(&pg->ps, | |
1439 | &p->path, type, result + sz, | |
1440 | maxlen - sz); | |
1441 | } | |
1442 | } | |
1443 | break; | |
1444 | ||
1445 | case STATUSTYPE_TABLE: | |
1446 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1447 | DMEMIT("%s ", pg->ps.type->name); | |
1448 | ||
1449 | if (pg->ps.type->status) | |
1450 | sz += pg->ps.type->status(&pg->ps, NULL, type, | |
1451 | result + sz, | |
1452 | maxlen - sz); | |
1453 | else | |
1454 | DMEMIT("0 "); | |
1455 | ||
1456 | DMEMIT("%u %u ", pg->nr_pgpaths, | |
1457 | pg->ps.type->table_args); | |
1458 | ||
1459 | list_for_each_entry(p, &pg->pgpaths, list) { | |
1460 | DMEMIT("%s ", p->path.dev->name); | |
1461 | if (pg->ps.type->status) | |
1462 | sz += pg->ps.type->status(&pg->ps, | |
1463 | &p->path, type, result + sz, | |
1464 | maxlen - sz); | |
1465 | } | |
1466 | } | |
1467 | break; | |
1468 | } | |
1469 | ||
1470 | spin_unlock_irqrestore(&m->lock, flags); | |
1da177e4 LT |
1471 | } |
1472 | ||
1473 | static int multipath_message(struct dm_target *ti, unsigned argc, char **argv) | |
1474 | { | |
6380f26f | 1475 | int r = -EINVAL; |
1da177e4 LT |
1476 | struct dm_dev *dev; |
1477 | struct multipath *m = (struct multipath *) ti->private; | |
1478 | action_fn action; | |
1479 | ||
6380f26f MA |
1480 | mutex_lock(&m->work_mutex); |
1481 | ||
c2f3d24b KU |
1482 | if (dm_suspended(ti)) { |
1483 | r = -EBUSY; | |
1484 | goto out; | |
1485 | } | |
1486 | ||
1da177e4 | 1487 | if (argc == 1) { |
498f0103 | 1488 | if (!strcasecmp(argv[0], "queue_if_no_path")) { |
6380f26f MA |
1489 | r = queue_if_no_path(m, 1, 0); |
1490 | goto out; | |
498f0103 | 1491 | } else if (!strcasecmp(argv[0], "fail_if_no_path")) { |
6380f26f MA |
1492 | r = queue_if_no_path(m, 0, 0); |
1493 | goto out; | |
1494 | } | |
1da177e4 LT |
1495 | } |
1496 | ||
6380f26f | 1497 | if (argc != 2) { |
a356e426 | 1498 | DMWARN("Invalid multipath message arguments. Expected 2 arguments, got %d.", argc); |
6380f26f MA |
1499 | goto out; |
1500 | } | |
1da177e4 | 1501 | |
498f0103 | 1502 | if (!strcasecmp(argv[0], "disable_group")) { |
6380f26f MA |
1503 | r = bypass_pg_num(m, argv[1], 1); |
1504 | goto out; | |
498f0103 | 1505 | } else if (!strcasecmp(argv[0], "enable_group")) { |
6380f26f MA |
1506 | r = bypass_pg_num(m, argv[1], 0); |
1507 | goto out; | |
498f0103 | 1508 | } else if (!strcasecmp(argv[0], "switch_group")) { |
6380f26f MA |
1509 | r = switch_pg_num(m, argv[1]); |
1510 | goto out; | |
498f0103 | 1511 | } else if (!strcasecmp(argv[0], "reinstate_path")) |
1da177e4 | 1512 | action = reinstate_path; |
498f0103 | 1513 | else if (!strcasecmp(argv[0], "fail_path")) |
1da177e4 | 1514 | action = fail_path; |
6380f26f | 1515 | else { |
a356e426 | 1516 | DMWARN("Unrecognised multipath message received: %s", argv[0]); |
6380f26f MA |
1517 | goto out; |
1518 | } | |
1da177e4 | 1519 | |
8215d6ec | 1520 | r = dm_get_device(ti, argv[1], dm_table_get_mode(ti->table), &dev); |
1da177e4 | 1521 | if (r) { |
72d94861 | 1522 | DMWARN("message: error getting device %s", |
1da177e4 | 1523 | argv[1]); |
6380f26f | 1524 | goto out; |
1da177e4 LT |
1525 | } |
1526 | ||
1527 | r = action_dev(m, dev, action); | |
1528 | ||
1529 | dm_put_device(ti, dev); | |
1530 | ||
6380f26f MA |
1531 | out: |
1532 | mutex_unlock(&m->work_mutex); | |
1da177e4 | 1533 | return r; |
1da177e4 LT |
1534 | } |
1535 | ||
e56f81e0 CH |
1536 | static int multipath_prepare_ioctl(struct dm_target *ti, |
1537 | struct block_device **bdev, fmode_t *mode) | |
9af4aa30 | 1538 | { |
35991652 | 1539 | struct multipath *m = ti->private; |
7ba10aa6 | 1540 | struct pgpath *pgpath; |
9af4aa30 | 1541 | unsigned long flags; |
35991652 MP |
1542 | int r; |
1543 | ||
35991652 | 1544 | r = 0; |
9af4aa30 MB |
1545 | |
1546 | spin_lock_irqsave(&m->lock, flags); | |
1547 | ||
1548 | if (!m->current_pgpath) | |
02ab823f | 1549 | __choose_pgpath(m, 0); |
9af4aa30 | 1550 | |
7ba10aa6 MS |
1551 | pgpath = m->current_pgpath; |
1552 | ||
1553 | if (pgpath) { | |
e56f81e0 CH |
1554 | *bdev = pgpath->path.dev->bdev; |
1555 | *mode = pgpath->path.dev->mode; | |
e90dae1f | 1556 | } |
9af4aa30 | 1557 | |
7ba10aa6 | 1558 | if ((pgpath && m->queue_io) || (!pgpath && m->queue_if_no_path)) |
6c182cd8 | 1559 | r = -ENOTCONN; |
e56f81e0 | 1560 | else if (!*bdev) |
9af4aa30 MB |
1561 | r = -EIO; |
1562 | ||
1563 | spin_unlock_irqrestore(&m->lock, flags); | |
1564 | ||
3e9f1be1 HR |
1565 | if (r == -ENOTCONN && !fatal_signal_pending(current)) { |
1566 | spin_lock_irqsave(&m->lock, flags); | |
1567 | if (!m->current_pg) { | |
1568 | /* Path status changed, redo selection */ | |
1569 | __choose_pgpath(m, 0); | |
1570 | } | |
1571 | if (m->pg_init_required) | |
1572 | __pg_init_all_paths(m); | |
4cdd2ad7 | 1573 | spin_unlock_irqrestore(&m->lock, flags); |
63d832c3 | 1574 | dm_table_run_md_queue_async(m->ti->table); |
3e9f1be1 | 1575 | } |
35991652 | 1576 | |
e56f81e0 CH |
1577 | /* |
1578 | * Only pass ioctls through if the device sizes match exactly. | |
1579 | */ | |
1580 | if (!r && ti->len != i_size_read((*bdev)->bd_inode) >> SECTOR_SHIFT) | |
1581 | return 1; | |
1582 | return r; | |
9af4aa30 MB |
1583 | } |
1584 | ||
af4874e0 MS |
1585 | static int multipath_iterate_devices(struct dm_target *ti, |
1586 | iterate_devices_callout_fn fn, void *data) | |
1587 | { | |
1588 | struct multipath *m = ti->private; | |
1589 | struct priority_group *pg; | |
1590 | struct pgpath *p; | |
1591 | int ret = 0; | |
1592 | ||
1593 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1594 | list_for_each_entry(p, &pg->pgpaths, list) { | |
5dea271b | 1595 | ret = fn(ti, p->path.dev, ti->begin, ti->len, data); |
af4874e0 MS |
1596 | if (ret) |
1597 | goto out; | |
1598 | } | |
1599 | } | |
1600 | ||
1601 | out: | |
1602 | return ret; | |
1603 | } | |
1604 | ||
f40c67f0 KU |
1605 | static int __pgpath_busy(struct pgpath *pgpath) |
1606 | { | |
1607 | struct request_queue *q = bdev_get_queue(pgpath->path.dev->bdev); | |
1608 | ||
52b09914 | 1609 | return blk_lld_busy(q); |
f40c67f0 KU |
1610 | } |
1611 | ||
1612 | /* | |
1613 | * We return "busy", only when we can map I/Os but underlying devices | |
1614 | * are busy (so even if we map I/Os now, the I/Os will wait on | |
1615 | * the underlying queue). | |
1616 | * In other words, if we want to kill I/Os or queue them inside us | |
1617 | * due to map unavailability, we don't return "busy". Otherwise, | |
1618 | * dm core won't give us the I/Os and we can't do what we want. | |
1619 | */ | |
1620 | static int multipath_busy(struct dm_target *ti) | |
1621 | { | |
1622 | int busy = 0, has_active = 0; | |
1623 | struct multipath *m = ti->private; | |
1624 | struct priority_group *pg; | |
1625 | struct pgpath *pgpath; | |
1626 | unsigned long flags; | |
1627 | ||
1628 | spin_lock_irqsave(&m->lock, flags); | |
1629 | ||
7a7a3b45 JN |
1630 | /* pg_init in progress or no paths available */ |
1631 | if (m->pg_init_in_progress || | |
1632 | (!m->nr_valid_paths && m->queue_if_no_path)) { | |
b63349a7 HR |
1633 | busy = 1; |
1634 | goto out; | |
1635 | } | |
f40c67f0 KU |
1636 | /* Guess which priority_group will be used at next mapping time */ |
1637 | if (unlikely(!m->current_pgpath && m->next_pg)) | |
1638 | pg = m->next_pg; | |
1639 | else if (likely(m->current_pg)) | |
1640 | pg = m->current_pg; | |
1641 | else | |
1642 | /* | |
1643 | * We don't know which pg will be used at next mapping time. | |
1644 | * We don't call __choose_pgpath() here to avoid to trigger | |
1645 | * pg_init just by busy checking. | |
1646 | * So we don't know whether underlying devices we will be using | |
1647 | * at next mapping time are busy or not. Just try mapping. | |
1648 | */ | |
1649 | goto out; | |
1650 | ||
1651 | /* | |
1652 | * If there is one non-busy active path at least, the path selector | |
1653 | * will be able to select it. So we consider such a pg as not busy. | |
1654 | */ | |
1655 | busy = 1; | |
1656 | list_for_each_entry(pgpath, &pg->pgpaths, list) | |
1657 | if (pgpath->is_active) { | |
1658 | has_active = 1; | |
1659 | ||
1660 | if (!__pgpath_busy(pgpath)) { | |
1661 | busy = 0; | |
1662 | break; | |
1663 | } | |
1664 | } | |
1665 | ||
1666 | if (!has_active) | |
1667 | /* | |
1668 | * No active path in this pg, so this pg won't be used and | |
1669 | * the current_pg will be changed at next mapping time. | |
1670 | * We need to try mapping to determine it. | |
1671 | */ | |
1672 | busy = 0; | |
1673 | ||
1674 | out: | |
1675 | spin_unlock_irqrestore(&m->lock, flags); | |
1676 | ||
1677 | return busy; | |
1678 | } | |
1679 | ||
1da177e4 LT |
1680 | /*----------------------------------------------------------------- |
1681 | * Module setup | |
1682 | *---------------------------------------------------------------*/ | |
1683 | static struct target_type multipath_target = { | |
1684 | .name = "multipath", | |
bfebd1cd | 1685 | .version = {1, 9, 0}, |
1da177e4 LT |
1686 | .module = THIS_MODULE, |
1687 | .ctr = multipath_ctr, | |
1688 | .dtr = multipath_dtr, | |
f40c67f0 | 1689 | .map_rq = multipath_map, |
e5863d9a MS |
1690 | .clone_and_map_rq = multipath_clone_and_map, |
1691 | .release_clone_rq = multipath_release_clone, | |
f40c67f0 | 1692 | .rq_end_io = multipath_end_io, |
1da177e4 | 1693 | .presuspend = multipath_presuspend, |
6df400ab | 1694 | .postsuspend = multipath_postsuspend, |
1da177e4 LT |
1695 | .resume = multipath_resume, |
1696 | .status = multipath_status, | |
1697 | .message = multipath_message, | |
e56f81e0 | 1698 | .prepare_ioctl = multipath_prepare_ioctl, |
af4874e0 | 1699 | .iterate_devices = multipath_iterate_devices, |
f40c67f0 | 1700 | .busy = multipath_busy, |
1da177e4 LT |
1701 | }; |
1702 | ||
1703 | static int __init dm_multipath_init(void) | |
1704 | { | |
1705 | int r; | |
1706 | ||
1707 | /* allocate a slab for the dm_ios */ | |
028867ac | 1708 | _mpio_cache = KMEM_CACHE(dm_mpath_io, 0); |
1da177e4 LT |
1709 | if (!_mpio_cache) |
1710 | return -ENOMEM; | |
1711 | ||
1712 | r = dm_register_target(&multipath_target); | |
1713 | if (r < 0) { | |
0cd33124 | 1714 | DMERR("register failed %d", r); |
ff658e9c JT |
1715 | r = -EINVAL; |
1716 | goto bad_register_target; | |
1da177e4 LT |
1717 | } |
1718 | ||
4d4d66ab | 1719 | kmultipathd = alloc_workqueue("kmpathd", WQ_MEM_RECLAIM, 0); |
c557308e | 1720 | if (!kmultipathd) { |
0cd33124 | 1721 | DMERR("failed to create workqueue kmpathd"); |
ff658e9c JT |
1722 | r = -ENOMEM; |
1723 | goto bad_alloc_kmultipathd; | |
c557308e AK |
1724 | } |
1725 | ||
bab7cfc7 CS |
1726 | /* |
1727 | * A separate workqueue is used to handle the device handlers | |
1728 | * to avoid overloading existing workqueue. Overloading the | |
1729 | * old workqueue would also create a bottleneck in the | |
1730 | * path of the storage hardware device activation. | |
1731 | */ | |
4d4d66ab TH |
1732 | kmpath_handlerd = alloc_ordered_workqueue("kmpath_handlerd", |
1733 | WQ_MEM_RECLAIM); | |
bab7cfc7 CS |
1734 | if (!kmpath_handlerd) { |
1735 | DMERR("failed to create workqueue kmpath_handlerd"); | |
ff658e9c JT |
1736 | r = -ENOMEM; |
1737 | goto bad_alloc_kmpath_handlerd; | |
bab7cfc7 CS |
1738 | } |
1739 | ||
72d94861 | 1740 | DMINFO("version %u.%u.%u loaded", |
1da177e4 LT |
1741 | multipath_target.version[0], multipath_target.version[1], |
1742 | multipath_target.version[2]); | |
1743 | ||
ff658e9c JT |
1744 | return 0; |
1745 | ||
1746 | bad_alloc_kmpath_handlerd: | |
1747 | destroy_workqueue(kmultipathd); | |
1748 | bad_alloc_kmultipathd: | |
1749 | dm_unregister_target(&multipath_target); | |
1750 | bad_register_target: | |
1751 | kmem_cache_destroy(_mpio_cache); | |
1752 | ||
1da177e4 LT |
1753 | return r; |
1754 | } | |
1755 | ||
1756 | static void __exit dm_multipath_exit(void) | |
1757 | { | |
bab7cfc7 | 1758 | destroy_workqueue(kmpath_handlerd); |
c557308e AK |
1759 | destroy_workqueue(kmultipathd); |
1760 | ||
10d3bd09 | 1761 | dm_unregister_target(&multipath_target); |
1da177e4 LT |
1762 | kmem_cache_destroy(_mpio_cache); |
1763 | } | |
1764 | ||
1da177e4 LT |
1765 | module_init(dm_multipath_init); |
1766 | module_exit(dm_multipath_exit); | |
1767 | ||
1768 | MODULE_DESCRIPTION(DM_NAME " multipath target"); | |
1769 | MODULE_AUTHOR("Sistina Software <dm-devel@redhat.com>"); | |
1770 | MODULE_LICENSE("GPL"); |