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 | ||
4cc96131 | 10 | #include "dm-rq.h" |
76e33fe4 | 11 | #include "dm-bio-record.h" |
1da177e4 | 12 | #include "dm-path-selector.h" |
b15546f9 | 13 | #include "dm-uevent.h" |
1da177e4 | 14 | |
e5863d9a | 15 | #include <linux/blkdev.h> |
1da177e4 LT |
16 | #include <linux/ctype.h> |
17 | #include <linux/init.h> | |
18 | #include <linux/mempool.h> | |
19 | #include <linux/module.h> | |
20 | #include <linux/pagemap.h> | |
21 | #include <linux/slab.h> | |
22 | #include <linux/time.h> | |
23 | #include <linux/workqueue.h> | |
35991652 | 24 | #include <linux/delay.h> |
cfae5c9b | 25 | #include <scsi/scsi_dh.h> |
60063497 | 26 | #include <linux/atomic.h> |
78ce23b5 | 27 | #include <linux/blk-mq.h> |
1da177e4 | 28 | |
72d94861 | 29 | #define DM_MSG_PREFIX "multipath" |
4e2d19e4 CS |
30 | #define DM_PG_INIT_DELAY_MSECS 2000 |
31 | #define DM_PG_INIT_DELAY_DEFAULT ((unsigned) -1) | |
1da177e4 LT |
32 | |
33 | /* Path properties */ | |
34 | struct pgpath { | |
35 | struct list_head list; | |
36 | ||
37 | struct priority_group *pg; /* Owning PG */ | |
38 | unsigned fail_count; /* Cumulative failure count */ | |
39 | ||
c922d5f7 | 40 | struct dm_path path; |
4e2d19e4 | 41 | struct delayed_work activate_path; |
be7d31cc MS |
42 | |
43 | bool is_active:1; /* Path status */ | |
1da177e4 LT |
44 | }; |
45 | ||
46 | #define path_to_pgpath(__pgp) container_of((__pgp), struct pgpath, path) | |
47 | ||
48 | /* | |
49 | * Paths are grouped into Priority Groups and numbered from 1 upwards. | |
50 | * Each has a path selector which controls which path gets used. | |
51 | */ | |
52 | struct priority_group { | |
53 | struct list_head list; | |
54 | ||
55 | struct multipath *m; /* Owning multipath instance */ | |
56 | struct path_selector ps; | |
57 | ||
58 | unsigned pg_num; /* Reference number */ | |
1da177e4 LT |
59 | unsigned nr_pgpaths; /* Number of paths in PG */ |
60 | struct list_head pgpaths; | |
be7d31cc MS |
61 | |
62 | bool bypassed:1; /* Temporarily bypass this PG? */ | |
1da177e4 LT |
63 | }; |
64 | ||
65 | /* Multipath context */ | |
66 | struct multipath { | |
67 | struct list_head list; | |
68 | struct dm_target *ti; | |
69 | ||
cfae5c9b | 70 | const char *hw_handler_name; |
2bfd2e13 | 71 | char *hw_handler_params; |
4e2d19e4 | 72 | |
1fbdd2b3 MS |
73 | spinlock_t lock; |
74 | ||
1da177e4 LT |
75 | unsigned nr_priority_groups; |
76 | struct list_head priority_groups; | |
4e2d19e4 CS |
77 | |
78 | wait_queue_head_t pg_init_wait; /* Wait for pg_init completion */ | |
79 | ||
1da177e4 LT |
80 | struct pgpath *current_pgpath; |
81 | struct priority_group *current_pg; | |
82 | struct priority_group *next_pg; /* Switch to this PG if set */ | |
1da177e4 | 83 | |
518257b1 | 84 | unsigned long flags; /* Multipath state flags */ |
1fbdd2b3 | 85 | |
c9e45581 | 86 | unsigned pg_init_retries; /* Number of times to retry pg_init */ |
4e2d19e4 | 87 | unsigned pg_init_delay_msecs; /* Number of msecs before pg_init retry */ |
1da177e4 | 88 | |
91e968aa MS |
89 | atomic_t nr_valid_paths; /* Total number of usable paths */ |
90 | atomic_t pg_init_in_progress; /* Only one pg_init allowed at once */ | |
91 | atomic_t pg_init_count; /* Number of times pg_init called */ | |
92 | ||
e83068a5 MS |
93 | unsigned queue_mode; |
94 | ||
1da177e4 | 95 | /* |
028867ac | 96 | * We must use a mempool of dm_mpath_io structs so that we |
1da177e4 LT |
97 | * can resubmit bios on error. |
98 | */ | |
99 | mempool_t *mpio_pool; | |
6380f26f MA |
100 | |
101 | struct mutex work_mutex; | |
20800cb3 | 102 | struct work_struct trigger_event; |
76e33fe4 MS |
103 | |
104 | struct work_struct process_queued_bios; | |
105 | struct bio_list queued_bios; | |
1da177e4 LT |
106 | }; |
107 | ||
108 | /* | |
76e33fe4 | 109 | * Context information attached to each io we process. |
1da177e4 | 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); |
76e33fe4 | 123 | static void process_queued_bios(struct work_struct *work); |
1da177e4 | 124 | |
518257b1 MS |
125 | /*----------------------------------------------- |
126 | * Multipath state flags. | |
127 | *-----------------------------------------------*/ | |
128 | ||
129 | #define MPATHF_QUEUE_IO 0 /* Must we queue all I/O? */ | |
130 | #define MPATHF_QUEUE_IF_NO_PATH 1 /* Queue I/O if last path fails? */ | |
131 | #define MPATHF_SAVED_QUEUE_IF_NO_PATH 2 /* Saved state during suspension */ | |
132 | #define MPATHF_RETAIN_ATTACHED_HW_HANDLER 3 /* If there's already a hw_handler present, don't change it. */ | |
133 | #define MPATHF_PG_INIT_DISABLED 4 /* pg_init is not currently allowed */ | |
134 | #define MPATHF_PG_INIT_REQUIRED 5 /* pg_init needs calling? */ | |
135 | #define MPATHF_PG_INIT_DELAY_RETRY 6 /* Delay pg_init retry? */ | |
1da177e4 LT |
136 | |
137 | /*----------------------------------------------- | |
138 | * Allocation routines | |
139 | *-----------------------------------------------*/ | |
140 | ||
141 | static struct pgpath *alloc_pgpath(void) | |
142 | { | |
e69fae56 | 143 | struct pgpath *pgpath = kzalloc(sizeof(*pgpath), GFP_KERNEL); |
1da177e4 | 144 | |
224cb3e9 | 145 | if (pgpath) { |
be7d31cc | 146 | pgpath->is_active = true; |
4e2d19e4 | 147 | INIT_DELAYED_WORK(&pgpath->activate_path, activate_path); |
224cb3e9 | 148 | } |
1da177e4 LT |
149 | |
150 | return pgpath; | |
151 | } | |
152 | ||
028867ac | 153 | static void free_pgpath(struct pgpath *pgpath) |
1da177e4 LT |
154 | { |
155 | kfree(pgpath); | |
156 | } | |
157 | ||
158 | static struct priority_group *alloc_priority_group(void) | |
159 | { | |
160 | struct priority_group *pg; | |
161 | ||
e69fae56 | 162 | pg = kzalloc(sizeof(*pg), GFP_KERNEL); |
1da177e4 | 163 | |
e69fae56 MM |
164 | if (pg) |
165 | INIT_LIST_HEAD(&pg->pgpaths); | |
1da177e4 LT |
166 | |
167 | return pg; | |
168 | } | |
169 | ||
170 | static void free_pgpaths(struct list_head *pgpaths, struct dm_target *ti) | |
171 | { | |
172 | struct pgpath *pgpath, *tmp; | |
173 | ||
174 | list_for_each_entry_safe(pgpath, tmp, pgpaths, list) { | |
175 | list_del(&pgpath->list); | |
176 | dm_put_device(ti, pgpath->path.dev); | |
177 | free_pgpath(pgpath); | |
178 | } | |
179 | } | |
180 | ||
181 | static void free_priority_group(struct priority_group *pg, | |
182 | struct dm_target *ti) | |
183 | { | |
184 | struct path_selector *ps = &pg->ps; | |
185 | ||
186 | if (ps->type) { | |
187 | ps->type->destroy(ps); | |
188 | dm_put_path_selector(ps->type); | |
189 | } | |
190 | ||
191 | free_pgpaths(&pg->pgpaths, ti); | |
192 | kfree(pg); | |
193 | } | |
194 | ||
e83068a5 | 195 | static struct multipath *alloc_multipath(struct dm_target *ti) |
1da177e4 LT |
196 | { |
197 | struct multipath *m; | |
198 | ||
e69fae56 | 199 | m = kzalloc(sizeof(*m), GFP_KERNEL); |
1da177e4 | 200 | if (m) { |
1da177e4 LT |
201 | INIT_LIST_HEAD(&m->priority_groups); |
202 | spin_lock_init(&m->lock); | |
518257b1 | 203 | set_bit(MPATHF_QUEUE_IO, &m->flags); |
91e968aa MS |
204 | atomic_set(&m->nr_valid_paths, 0); |
205 | atomic_set(&m->pg_init_in_progress, 0); | |
206 | atomic_set(&m->pg_init_count, 0); | |
4e2d19e4 | 207 | m->pg_init_delay_msecs = DM_PG_INIT_DELAY_DEFAULT; |
c4028958 | 208 | INIT_WORK(&m->trigger_event, trigger_event); |
2bded7bd | 209 | init_waitqueue_head(&m->pg_init_wait); |
6380f26f | 210 | mutex_init(&m->work_mutex); |
8637a6bf MS |
211 | |
212 | m->mpio_pool = NULL; | |
e83068a5 | 213 | m->queue_mode = DM_TYPE_NONE; |
76e33fe4 | 214 | |
28f16c20 MM |
215 | m->ti = ti; |
216 | ti->private = m; | |
1da177e4 LT |
217 | } |
218 | ||
219 | return m; | |
220 | } | |
221 | ||
e83068a5 MS |
222 | static int alloc_multipath_stage2(struct dm_target *ti, struct multipath *m) |
223 | { | |
224 | if (m->queue_mode == DM_TYPE_NONE) { | |
225 | /* | |
226 | * Default to request-based. | |
227 | */ | |
228 | if (dm_use_blk_mq(dm_table_get_md(ti->table))) | |
229 | m->queue_mode = DM_TYPE_MQ_REQUEST_BASED; | |
230 | else | |
231 | m->queue_mode = DM_TYPE_REQUEST_BASED; | |
232 | } | |
233 | ||
234 | if (m->queue_mode == DM_TYPE_REQUEST_BASED) { | |
235 | unsigned min_ios = dm_get_reserved_rq_based_ios(); | |
236 | ||
237 | m->mpio_pool = mempool_create_slab_pool(min_ios, _mpio_cache); | |
238 | if (!m->mpio_pool) | |
239 | return -ENOMEM; | |
240 | } | |
241 | else if (m->queue_mode == DM_TYPE_BIO_BASED) { | |
242 | INIT_WORK(&m->process_queued_bios, process_queued_bios); | |
243 | /* | |
244 | * bio-based doesn't support any direct scsi_dh management; | |
245 | * it just discovers if a scsi_dh is attached. | |
246 | */ | |
247 | set_bit(MPATHF_RETAIN_ATTACHED_HW_HANDLER, &m->flags); | |
248 | } | |
249 | ||
250 | dm_table_set_type(ti->table, m->queue_mode); | |
251 | ||
252 | return 0; | |
253 | } | |
254 | ||
1da177e4 LT |
255 | static void free_multipath(struct multipath *m) |
256 | { | |
257 | struct priority_group *pg, *tmp; | |
1da177e4 LT |
258 | |
259 | list_for_each_entry_safe(pg, tmp, &m->priority_groups, list) { | |
260 | list_del(&pg->list); | |
261 | free_priority_group(pg, m->ti); | |
262 | } | |
263 | ||
cfae5c9b | 264 | kfree(m->hw_handler_name); |
2bfd2e13 | 265 | kfree(m->hw_handler_params); |
1da177e4 LT |
266 | mempool_destroy(m->mpio_pool); |
267 | kfree(m); | |
268 | } | |
269 | ||
2eff1924 MS |
270 | static struct dm_mpath_io *get_mpio(union map_info *info) |
271 | { | |
272 | return info->ptr; | |
273 | } | |
274 | ||
275 | static struct dm_mpath_io *set_mpio(struct multipath *m, union map_info *info) | |
466891f9 JN |
276 | { |
277 | struct dm_mpath_io *mpio; | |
278 | ||
8637a6bf MS |
279 | if (!m->mpio_pool) { |
280 | /* Use blk-mq pdu memory requested via per_io_data_size */ | |
2eff1924 | 281 | mpio = get_mpio(info); |
8637a6bf MS |
282 | memset(mpio, 0, sizeof(*mpio)); |
283 | return mpio; | |
284 | } | |
285 | ||
466891f9 JN |
286 | mpio = mempool_alloc(m->mpio_pool, GFP_ATOMIC); |
287 | if (!mpio) | |
2eff1924 | 288 | return NULL; |
466891f9 JN |
289 | |
290 | memset(mpio, 0, sizeof(*mpio)); | |
291 | info->ptr = mpio; | |
292 | ||
2eff1924 | 293 | return mpio; |
466891f9 JN |
294 | } |
295 | ||
2eff1924 | 296 | static void clear_request_fn_mpio(struct multipath *m, union map_info *info) |
466891f9 | 297 | { |
2eff1924 | 298 | /* Only needed for non blk-mq (.request_fn) multipath */ |
8637a6bf MS |
299 | if (m->mpio_pool) { |
300 | struct dm_mpath_io *mpio = info->ptr; | |
466891f9 | 301 | |
8637a6bf MS |
302 | info->ptr = NULL; |
303 | mempool_free(mpio, m->mpio_pool); | |
304 | } | |
466891f9 | 305 | } |
1da177e4 | 306 | |
bf661be1 MS |
307 | static size_t multipath_per_bio_data_size(void) |
308 | { | |
309 | return sizeof(struct dm_mpath_io) + sizeof(struct dm_bio_details); | |
310 | } | |
311 | ||
76e33fe4 MS |
312 | static struct dm_mpath_io *get_mpio_from_bio(struct bio *bio) |
313 | { | |
bf661be1 | 314 | return dm_per_bio_data(bio, multipath_per_bio_data_size()); |
76e33fe4 MS |
315 | } |
316 | ||
bf661be1 | 317 | static struct dm_bio_details *get_bio_details_from_bio(struct bio *bio) |
76e33fe4 | 318 | { |
bf661be1 | 319 | /* dm_bio_details is immediately after the dm_mpath_io in bio's per-bio-data */ |
76e33fe4 | 320 | struct dm_mpath_io *mpio = get_mpio_from_bio(bio); |
bf661be1 MS |
321 | void *bio_details = mpio + 1; |
322 | ||
323 | return bio_details; | |
324 | } | |
325 | ||
326 | static void multipath_init_per_bio_data(struct bio *bio, struct dm_mpath_io **mpio_p, | |
327 | struct dm_bio_details **bio_details_p) | |
328 | { | |
329 | struct dm_mpath_io *mpio = get_mpio_from_bio(bio); | |
330 | struct dm_bio_details *bio_details = get_bio_details_from_bio(bio); | |
76e33fe4 MS |
331 | |
332 | memset(mpio, 0, sizeof(*mpio)); | |
bf661be1 MS |
333 | memset(bio_details, 0, sizeof(*bio_details)); |
334 | dm_bio_record(bio_details, bio); | |
76e33fe4 | 335 | |
bf661be1 MS |
336 | if (mpio_p) |
337 | *mpio_p = mpio; | |
338 | if (bio_details_p) | |
339 | *bio_details_p = bio_details; | |
76e33fe4 MS |
340 | } |
341 | ||
1da177e4 LT |
342 | /*----------------------------------------------- |
343 | * Path selection | |
344 | *-----------------------------------------------*/ | |
345 | ||
3e9f1be1 | 346 | static int __pg_init_all_paths(struct multipath *m) |
fb612642 KU |
347 | { |
348 | struct pgpath *pgpath; | |
4e2d19e4 | 349 | unsigned long pg_init_delay = 0; |
fb612642 | 350 | |
91e968aa | 351 | if (atomic_read(&m->pg_init_in_progress) || test_bit(MPATHF_PG_INIT_DISABLED, &m->flags)) |
3e9f1be1 | 352 | return 0; |
17f4ff45 | 353 | |
91e968aa | 354 | atomic_inc(&m->pg_init_count); |
518257b1 | 355 | clear_bit(MPATHF_PG_INIT_REQUIRED, &m->flags); |
3e9f1be1 HR |
356 | |
357 | /* Check here to reset pg_init_required */ | |
358 | if (!m->current_pg) | |
359 | return 0; | |
360 | ||
518257b1 | 361 | if (test_bit(MPATHF_PG_INIT_DELAY_RETRY, &m->flags)) |
4e2d19e4 CS |
362 | pg_init_delay = msecs_to_jiffies(m->pg_init_delay_msecs != DM_PG_INIT_DELAY_DEFAULT ? |
363 | m->pg_init_delay_msecs : DM_PG_INIT_DELAY_MSECS); | |
fb612642 KU |
364 | list_for_each_entry(pgpath, &m->current_pg->pgpaths, list) { |
365 | /* Skip failed paths */ | |
366 | if (!pgpath->is_active) | |
367 | continue; | |
4e2d19e4 CS |
368 | if (queue_delayed_work(kmpath_handlerd, &pgpath->activate_path, |
369 | pg_init_delay)) | |
91e968aa | 370 | atomic_inc(&m->pg_init_in_progress); |
fb612642 | 371 | } |
91e968aa | 372 | return atomic_read(&m->pg_init_in_progress); |
fb612642 KU |
373 | } |
374 | ||
2da1610a | 375 | static int pg_init_all_paths(struct multipath *m) |
1da177e4 | 376 | { |
2da1610a MS |
377 | int r; |
378 | unsigned long flags; | |
379 | ||
380 | spin_lock_irqsave(&m->lock, flags); | |
381 | r = __pg_init_all_paths(m); | |
382 | spin_unlock_irqrestore(&m->lock, flags); | |
383 | ||
384 | return r; | |
385 | } | |
386 | ||
387 | static void __switch_pg(struct multipath *m, struct priority_group *pg) | |
388 | { | |
389 | m->current_pg = pg; | |
1da177e4 LT |
390 | |
391 | /* Must we initialise the PG first, and queue I/O till it's ready? */ | |
cfae5c9b | 392 | if (m->hw_handler_name) { |
518257b1 MS |
393 | set_bit(MPATHF_PG_INIT_REQUIRED, &m->flags); |
394 | set_bit(MPATHF_QUEUE_IO, &m->flags); | |
1da177e4 | 395 | } else { |
518257b1 MS |
396 | clear_bit(MPATHF_PG_INIT_REQUIRED, &m->flags); |
397 | clear_bit(MPATHF_QUEUE_IO, &m->flags); | |
1da177e4 | 398 | } |
c9e45581 | 399 | |
91e968aa | 400 | atomic_set(&m->pg_init_count, 0); |
1da177e4 LT |
401 | } |
402 | ||
2da1610a MS |
403 | static struct pgpath *choose_path_in_pg(struct multipath *m, |
404 | struct priority_group *pg, | |
405 | size_t nr_bytes) | |
1da177e4 | 406 | { |
2da1610a | 407 | unsigned long flags; |
c922d5f7 | 408 | struct dm_path *path; |
2da1610a | 409 | struct pgpath *pgpath; |
1da177e4 | 410 | |
90a4323c | 411 | path = pg->ps.type->select_path(&pg->ps, nr_bytes); |
1da177e4 | 412 | if (!path) |
2da1610a | 413 | return ERR_PTR(-ENXIO); |
1da177e4 | 414 | |
2da1610a | 415 | pgpath = path_to_pgpath(path); |
1da177e4 | 416 | |
2da1610a MS |
417 | if (unlikely(lockless_dereference(m->current_pg) != pg)) { |
418 | /* Only update current_pgpath if pg changed */ | |
419 | spin_lock_irqsave(&m->lock, flags); | |
420 | m->current_pgpath = pgpath; | |
421 | __switch_pg(m, pg); | |
422 | spin_unlock_irqrestore(&m->lock, flags); | |
423 | } | |
1da177e4 | 424 | |
2da1610a | 425 | return pgpath; |
1da177e4 LT |
426 | } |
427 | ||
2da1610a | 428 | static struct pgpath *choose_pgpath(struct multipath *m, size_t nr_bytes) |
1da177e4 | 429 | { |
2da1610a | 430 | unsigned long flags; |
1da177e4 | 431 | struct priority_group *pg; |
2da1610a | 432 | struct pgpath *pgpath; |
be7d31cc | 433 | bool bypassed = true; |
1da177e4 | 434 | |
91e968aa | 435 | if (!atomic_read(&m->nr_valid_paths)) { |
518257b1 | 436 | clear_bit(MPATHF_QUEUE_IO, &m->flags); |
1da177e4 | 437 | goto failed; |
1f271972 | 438 | } |
1da177e4 LT |
439 | |
440 | /* Were we instructed to switch PG? */ | |
2da1610a MS |
441 | if (lockless_dereference(m->next_pg)) { |
442 | spin_lock_irqsave(&m->lock, flags); | |
1da177e4 | 443 | pg = m->next_pg; |
2da1610a MS |
444 | if (!pg) { |
445 | spin_unlock_irqrestore(&m->lock, flags); | |
446 | goto check_current_pg; | |
447 | } | |
1da177e4 | 448 | m->next_pg = NULL; |
2da1610a MS |
449 | spin_unlock_irqrestore(&m->lock, flags); |
450 | pgpath = choose_path_in_pg(m, pg, nr_bytes); | |
451 | if (!IS_ERR_OR_NULL(pgpath)) | |
452 | return pgpath; | |
1da177e4 LT |
453 | } |
454 | ||
455 | /* Don't change PG until it has no remaining paths */ | |
2da1610a MS |
456 | check_current_pg: |
457 | pg = lockless_dereference(m->current_pg); | |
458 | if (pg) { | |
459 | pgpath = choose_path_in_pg(m, pg, nr_bytes); | |
460 | if (!IS_ERR_OR_NULL(pgpath)) | |
461 | return pgpath; | |
462 | } | |
1da177e4 LT |
463 | |
464 | /* | |
465 | * Loop through priority groups until we find a valid path. | |
466 | * First time we skip PGs marked 'bypassed'. | |
f220fd4e MC |
467 | * Second time we only try the ones we skipped, but set |
468 | * pg_init_delay_retry so we do not hammer controllers. | |
1da177e4 LT |
469 | */ |
470 | do { | |
471 | list_for_each_entry(pg, &m->priority_groups, list) { | |
472 | if (pg->bypassed == bypassed) | |
473 | continue; | |
2da1610a MS |
474 | pgpath = choose_path_in_pg(m, pg, nr_bytes); |
475 | if (!IS_ERR_OR_NULL(pgpath)) { | |
f220fd4e | 476 | if (!bypassed) |
518257b1 | 477 | set_bit(MPATHF_PG_INIT_DELAY_RETRY, &m->flags); |
2da1610a | 478 | return pgpath; |
f220fd4e | 479 | } |
1da177e4 LT |
480 | } |
481 | } while (bypassed--); | |
482 | ||
483 | failed: | |
2da1610a | 484 | spin_lock_irqsave(&m->lock, flags); |
1da177e4 LT |
485 | m->current_pgpath = NULL; |
486 | m->current_pg = NULL; | |
2da1610a MS |
487 | spin_unlock_irqrestore(&m->lock, flags); |
488 | ||
489 | return NULL; | |
1da177e4 LT |
490 | } |
491 | ||
45e15720 KU |
492 | /* |
493 | * Check whether bios must be queued in the device-mapper core rather | |
494 | * than here in the target. | |
495 | * | |
45e15720 KU |
496 | * If m->queue_if_no_path and m->saved_queue_if_no_path hold the |
497 | * same value then we are not between multipath_presuspend() | |
498 | * and multipath_resume() calls and we have no need to check | |
499 | * for the DMF_NOFLUSH_SUSPENDING flag. | |
500 | */ | |
76e33fe4 MS |
501 | static bool __must_push_back(struct multipath *m) |
502 | { | |
503 | return ((test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags) != | |
504 | test_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &m->flags)) && | |
505 | dm_noflush_suspending(m->ti)); | |
506 | } | |
507 | ||
508 | static bool must_push_back_rq(struct multipath *m) | |
45e15720 | 509 | { |
518257b1 | 510 | return (test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags) || |
76e33fe4 MS |
511 | __must_push_back(m)); |
512 | } | |
513 | ||
514 | static bool must_push_back_bio(struct multipath *m) | |
515 | { | |
516 | return __must_push_back(m); | |
45e15720 KU |
517 | } |
518 | ||
36fcffcc | 519 | /* |
76e33fe4 | 520 | * Map cloned requests (request-based multipath) |
36fcffcc | 521 | */ |
e5863d9a MS |
522 | static int __multipath_map(struct dm_target *ti, struct request *clone, |
523 | union map_info *map_context, | |
524 | struct request *rq, struct request **__clone) | |
1da177e4 | 525 | { |
7943bd6d | 526 | struct multipath *m = ti->private; |
e3bde04f | 527 | int r = DM_MAPIO_REQUEUE; |
e5863d9a | 528 | size_t nr_bytes = clone ? blk_rq_bytes(clone) : blk_rq_bytes(rq); |
1da177e4 | 529 | struct pgpath *pgpath; |
f40c67f0 | 530 | struct block_device *bdev; |
e3bde04f | 531 | struct dm_mpath_io *mpio; |
1da177e4 | 532 | |
1da177e4 | 533 | /* Do we need to select a new pgpath? */ |
2da1610a MS |
534 | pgpath = lockless_dereference(m->current_pgpath); |
535 | if (!pgpath || !test_bit(MPATHF_QUEUE_IO, &m->flags)) | |
536 | pgpath = choose_pgpath(m, nr_bytes); | |
1da177e4 | 537 | |
9bf59a61 | 538 | if (!pgpath) { |
76e33fe4 | 539 | if (!must_push_back_rq(m)) |
9bf59a61 | 540 | r = -EIO; /* Failed */ |
2da1610a | 541 | return r; |
518257b1 MS |
542 | } else if (test_bit(MPATHF_QUEUE_IO, &m->flags) || |
543 | test_bit(MPATHF_PG_INIT_REQUIRED, &m->flags)) { | |
2da1610a MS |
544 | pg_init_all_paths(m); |
545 | return r; | |
9bf59a61 | 546 | } |
6afbc01d | 547 | |
2eff1924 MS |
548 | mpio = set_mpio(m, map_context); |
549 | if (!mpio) | |
9bf59a61 | 550 | /* ENOMEM, requeue */ |
2da1610a | 551 | return r; |
9bf59a61 | 552 | |
2eb6e1e3 KB |
553 | mpio->pgpath = pgpath; |
554 | mpio->nr_bytes = nr_bytes; | |
555 | ||
9bf59a61 | 556 | bdev = pgpath->path.dev->bdev; |
2eb6e1e3 | 557 | |
e5863d9a | 558 | if (clone) { |
c5248f79 MS |
559 | /* |
560 | * Old request-based interface: allocated clone is passed in. | |
561 | * Used by: .request_fn stacked on .request_fn path(s). | |
562 | */ | |
e5863d9a MS |
563 | clone->q = bdev_get_queue(bdev); |
564 | clone->rq_disk = bdev->bd_disk; | |
565 | clone->cmd_flags |= REQ_FAILFAST_TRANSPORT; | |
566 | } else { | |
eca7ee6d MS |
567 | /* |
568 | * blk-mq request-based interface; used by both: | |
569 | * .request_fn stacked on blk-mq path(s) and | |
570 | * blk-mq stacked on blk-mq path(s). | |
571 | */ | |
78ce23b5 MS |
572 | *__clone = blk_mq_alloc_request(bdev_get_queue(bdev), |
573 | rq_data_dir(rq), BLK_MQ_REQ_NOWAIT); | |
4c6dd53d | 574 | if (IS_ERR(*__clone)) { |
e5863d9a | 575 | /* ENOMEM, requeue */ |
2eff1924 | 576 | clear_request_fn_mpio(m, map_context); |
e5863d9a | 577 | return r; |
4c6dd53d | 578 | } |
e5863d9a MS |
579 | (*__clone)->bio = (*__clone)->biotail = NULL; |
580 | (*__clone)->rq_disk = bdev->bd_disk; | |
581 | (*__clone)->cmd_flags |= REQ_FAILFAST_TRANSPORT; | |
582 | } | |
583 | ||
9bf59a61 MS |
584 | if (pgpath->pg->ps.type->start_io) |
585 | pgpath->pg->ps.type->start_io(&pgpath->pg->ps, | |
586 | &pgpath->path, | |
587 | nr_bytes); | |
2eb6e1e3 | 588 | return DM_MAPIO_REMAPPED; |
1da177e4 LT |
589 | } |
590 | ||
e5863d9a MS |
591 | static int multipath_map(struct dm_target *ti, struct request *clone, |
592 | union map_info *map_context) | |
593 | { | |
594 | return __multipath_map(ti, clone, map_context, NULL, NULL); | |
595 | } | |
596 | ||
597 | static int multipath_clone_and_map(struct dm_target *ti, struct request *rq, | |
598 | union map_info *map_context, | |
599 | struct request **clone) | |
600 | { | |
601 | return __multipath_map(ti, NULL, map_context, rq, clone); | |
602 | } | |
603 | ||
604 | static void multipath_release_clone(struct request *clone) | |
605 | { | |
78ce23b5 | 606 | blk_mq_free_request(clone); |
e5863d9a MS |
607 | } |
608 | ||
76e33fe4 MS |
609 | /* |
610 | * Map cloned bios (bio-based multipath) | |
611 | */ | |
612 | static int __multipath_map_bio(struct multipath *m, struct bio *bio, struct dm_mpath_io *mpio) | |
613 | { | |
614 | size_t nr_bytes = bio->bi_iter.bi_size; | |
615 | struct pgpath *pgpath; | |
616 | unsigned long flags; | |
617 | bool queue_io; | |
618 | ||
619 | /* Do we need to select a new pgpath? */ | |
620 | pgpath = lockless_dereference(m->current_pgpath); | |
621 | queue_io = test_bit(MPATHF_QUEUE_IO, &m->flags); | |
622 | if (!pgpath || !queue_io) | |
623 | pgpath = choose_pgpath(m, nr_bytes); | |
624 | ||
625 | if ((pgpath && queue_io) || | |
626 | (!pgpath && test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags))) { | |
627 | /* Queue for the daemon to resubmit */ | |
628 | spin_lock_irqsave(&m->lock, flags); | |
629 | bio_list_add(&m->queued_bios, bio); | |
630 | spin_unlock_irqrestore(&m->lock, flags); | |
631 | /* PG_INIT_REQUIRED cannot be set without QUEUE_IO */ | |
632 | if (queue_io || test_bit(MPATHF_PG_INIT_REQUIRED, &m->flags)) | |
633 | pg_init_all_paths(m); | |
634 | else if (!queue_io) | |
635 | queue_work(kmultipathd, &m->process_queued_bios); | |
636 | return DM_MAPIO_SUBMITTED; | |
637 | } | |
638 | ||
639 | if (!pgpath) { | |
640 | if (!must_push_back_bio(m)) | |
641 | return -EIO; | |
642 | return DM_MAPIO_REQUEUE; | |
643 | } | |
644 | ||
645 | mpio->pgpath = pgpath; | |
646 | mpio->nr_bytes = nr_bytes; | |
647 | ||
648 | bio->bi_error = 0; | |
649 | bio->bi_bdev = pgpath->path.dev->bdev; | |
650 | bio->bi_rw |= REQ_FAILFAST_TRANSPORT; | |
651 | ||
652 | if (pgpath->pg->ps.type->start_io) | |
653 | pgpath->pg->ps.type->start_io(&pgpath->pg->ps, | |
654 | &pgpath->path, | |
655 | nr_bytes); | |
656 | return DM_MAPIO_REMAPPED; | |
657 | } | |
658 | ||
659 | static int multipath_map_bio(struct dm_target *ti, struct bio *bio) | |
660 | { | |
661 | struct multipath *m = ti->private; | |
bf661be1 MS |
662 | struct dm_mpath_io *mpio = NULL; |
663 | ||
664 | multipath_init_per_bio_data(bio, &mpio, NULL); | |
76e33fe4 MS |
665 | |
666 | return __multipath_map_bio(m, bio, mpio); | |
667 | } | |
668 | ||
669 | static void process_queued_bios_list(struct multipath *m) | |
670 | { | |
e83068a5 | 671 | if (m->queue_mode == DM_TYPE_BIO_BASED) |
76e33fe4 MS |
672 | queue_work(kmultipathd, &m->process_queued_bios); |
673 | } | |
674 | ||
675 | static void process_queued_bios(struct work_struct *work) | |
676 | { | |
677 | int r; | |
678 | unsigned long flags; | |
679 | struct bio *bio; | |
680 | struct bio_list bios; | |
681 | struct blk_plug plug; | |
682 | struct multipath *m = | |
683 | container_of(work, struct multipath, process_queued_bios); | |
684 | ||
685 | bio_list_init(&bios); | |
686 | ||
687 | spin_lock_irqsave(&m->lock, flags); | |
688 | ||
689 | if (bio_list_empty(&m->queued_bios)) { | |
690 | spin_unlock_irqrestore(&m->lock, flags); | |
691 | return; | |
692 | } | |
693 | ||
694 | bio_list_merge(&bios, &m->queued_bios); | |
695 | bio_list_init(&m->queued_bios); | |
696 | ||
697 | spin_unlock_irqrestore(&m->lock, flags); | |
698 | ||
699 | blk_start_plug(&plug); | |
700 | while ((bio = bio_list_pop(&bios))) { | |
701 | r = __multipath_map_bio(m, bio, get_mpio_from_bio(bio)); | |
702 | if (r < 0 || r == DM_MAPIO_REQUEUE) { | |
703 | bio->bi_error = r; | |
704 | bio_endio(bio); | |
705 | } else if (r == DM_MAPIO_REMAPPED) | |
706 | generic_make_request(bio); | |
707 | } | |
708 | blk_finish_plug(&plug); | |
709 | } | |
710 | ||
1da177e4 LT |
711 | /* |
712 | * If we run out of usable paths, should we queue I/O or error it? | |
713 | */ | |
be7d31cc MS |
714 | static int queue_if_no_path(struct multipath *m, bool queue_if_no_path, |
715 | bool save_old_value) | |
1da177e4 LT |
716 | { |
717 | unsigned long flags; | |
718 | ||
719 | spin_lock_irqsave(&m->lock, flags); | |
720 | ||
518257b1 MS |
721 | if (save_old_value) { |
722 | if (test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) | |
723 | set_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &m->flags); | |
724 | else | |
725 | clear_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &m->flags); | |
726 | } else { | |
727 | if (queue_if_no_path) | |
728 | set_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &m->flags); | |
729 | else | |
730 | clear_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &m->flags); | |
731 | } | |
732 | if (queue_if_no_path) | |
733 | set_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags); | |
485ef69e | 734 | else |
518257b1 MS |
735 | clear_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags); |
736 | ||
1da177e4 LT |
737 | spin_unlock_irqrestore(&m->lock, flags); |
738 | ||
76e33fe4 | 739 | if (!queue_if_no_path) { |
63d832c3 | 740 | dm_table_run_md_queue_async(m->ti->table); |
76e33fe4 MS |
741 | process_queued_bios_list(m); |
742 | } | |
63d832c3 | 743 | |
1da177e4 LT |
744 | return 0; |
745 | } | |
746 | ||
1da177e4 LT |
747 | /* |
748 | * An event is triggered whenever a path is taken out of use. | |
749 | * Includes path failure and PG bypass. | |
750 | */ | |
c4028958 | 751 | static void trigger_event(struct work_struct *work) |
1da177e4 | 752 | { |
c4028958 DH |
753 | struct multipath *m = |
754 | container_of(work, struct multipath, trigger_event); | |
1da177e4 LT |
755 | |
756 | dm_table_event(m->ti->table); | |
757 | } | |
758 | ||
759 | /*----------------------------------------------------------------- | |
760 | * Constructor/argument parsing: | |
761 | * <#multipath feature args> [<arg>]* | |
762 | * <#hw_handler args> [hw_handler [<arg>]*] | |
763 | * <#priority groups> | |
764 | * <initial priority group> | |
765 | * [<selector> <#selector args> [<arg>]* | |
766 | * <#paths> <#per-path selector args> | |
767 | * [<path> [<arg>]* ]+ ]+ | |
768 | *---------------------------------------------------------------*/ | |
498f0103 | 769 | static int parse_path_selector(struct dm_arg_set *as, struct priority_group *pg, |
1da177e4 LT |
770 | struct dm_target *ti) |
771 | { | |
772 | int r; | |
773 | struct path_selector_type *pst; | |
774 | unsigned ps_argc; | |
775 | ||
498f0103 | 776 | static struct dm_arg _args[] = { |
72d94861 | 777 | {0, 1024, "invalid number of path selector args"}, |
1da177e4 LT |
778 | }; |
779 | ||
498f0103 | 780 | pst = dm_get_path_selector(dm_shift_arg(as)); |
1da177e4 | 781 | if (!pst) { |
72d94861 | 782 | ti->error = "unknown path selector type"; |
1da177e4 LT |
783 | return -EINVAL; |
784 | } | |
785 | ||
498f0103 | 786 | r = dm_read_arg_group(_args, as, &ps_argc, &ti->error); |
371b2e34 MP |
787 | if (r) { |
788 | dm_put_path_selector(pst); | |
1da177e4 | 789 | return -EINVAL; |
371b2e34 | 790 | } |
1da177e4 LT |
791 | |
792 | r = pst->create(&pg->ps, ps_argc, as->argv); | |
793 | if (r) { | |
794 | dm_put_path_selector(pst); | |
72d94861 | 795 | ti->error = "path selector constructor failed"; |
1da177e4 LT |
796 | return r; |
797 | } | |
798 | ||
799 | pg->ps.type = pst; | |
498f0103 | 800 | dm_consume_args(as, ps_argc); |
1da177e4 LT |
801 | |
802 | return 0; | |
803 | } | |
804 | ||
498f0103 | 805 | static struct pgpath *parse_path(struct dm_arg_set *as, struct path_selector *ps, |
1da177e4 LT |
806 | struct dm_target *ti) |
807 | { | |
808 | int r; | |
809 | struct pgpath *p; | |
ae11b1b3 | 810 | struct multipath *m = ti->private; |
a58a935d MS |
811 | struct request_queue *q = NULL; |
812 | const char *attached_handler_name; | |
1da177e4 LT |
813 | |
814 | /* we need at least a path arg */ | |
815 | if (as->argc < 1) { | |
72d94861 | 816 | ti->error = "no device given"; |
01460f35 | 817 | return ERR_PTR(-EINVAL); |
1da177e4 LT |
818 | } |
819 | ||
820 | p = alloc_pgpath(); | |
821 | if (!p) | |
01460f35 | 822 | return ERR_PTR(-ENOMEM); |
1da177e4 | 823 | |
498f0103 | 824 | r = dm_get_device(ti, dm_shift_arg(as), dm_table_get_mode(ti->table), |
8215d6ec | 825 | &p->path.dev); |
1da177e4 | 826 | if (r) { |
72d94861 | 827 | ti->error = "error getting device"; |
1da177e4 LT |
828 | goto bad; |
829 | } | |
830 | ||
518257b1 | 831 | if (test_bit(MPATHF_RETAIN_ATTACHED_HW_HANDLER, &m->flags) || m->hw_handler_name) |
a58a935d MS |
832 | q = bdev_get_queue(p->path.dev->bdev); |
833 | ||
518257b1 | 834 | if (test_bit(MPATHF_RETAIN_ATTACHED_HW_HANDLER, &m->flags)) { |
1bab0de0 | 835 | retain: |
a58a935d MS |
836 | attached_handler_name = scsi_dh_attached_handler_name(q, GFP_KERNEL); |
837 | if (attached_handler_name) { | |
838 | /* | |
839 | * Reset hw_handler_name to match the attached handler | |
840 | * and clear any hw_handler_params associated with the | |
841 | * ignored handler. | |
842 | * | |
843 | * NB. This modifies the table line to show the actual | |
844 | * handler instead of the original table passed in. | |
845 | */ | |
846 | kfree(m->hw_handler_name); | |
847 | m->hw_handler_name = attached_handler_name; | |
848 | ||
849 | kfree(m->hw_handler_params); | |
850 | m->hw_handler_params = NULL; | |
851 | } | |
852 | } | |
a0cf7ea9 | 853 | |
a58a935d | 854 | if (m->hw_handler_name) { |
a0cf7ea9 HR |
855 | r = scsi_dh_attach(q, m->hw_handler_name); |
856 | if (r == -EBUSY) { | |
1bab0de0 | 857 | char b[BDEVNAME_SIZE]; |
a0cf7ea9 | 858 | |
1bab0de0 CH |
859 | printk(KERN_INFO "dm-mpath: retaining handler on device %s\n", |
860 | bdevname(p->path.dev->bdev, b)); | |
861 | goto retain; | |
862 | } | |
ae11b1b3 | 863 | if (r < 0) { |
a0cf7ea9 | 864 | ti->error = "error attaching hardware handler"; |
ae11b1b3 HR |
865 | dm_put_device(ti, p->path.dev); |
866 | goto bad; | |
867 | } | |
2bfd2e13 CS |
868 | |
869 | if (m->hw_handler_params) { | |
870 | r = scsi_dh_set_params(q, m->hw_handler_params); | |
871 | if (r < 0) { | |
872 | ti->error = "unable to set hardware " | |
873 | "handler parameters"; | |
2bfd2e13 CS |
874 | dm_put_device(ti, p->path.dev); |
875 | goto bad; | |
876 | } | |
877 | } | |
ae11b1b3 HR |
878 | } |
879 | ||
1da177e4 LT |
880 | r = ps->type->add_path(ps, &p->path, as->argc, as->argv, &ti->error); |
881 | if (r) { | |
882 | dm_put_device(ti, p->path.dev); | |
883 | goto bad; | |
884 | } | |
885 | ||
886 | return p; | |
887 | ||
888 | bad: | |
889 | free_pgpath(p); | |
01460f35 | 890 | return ERR_PTR(r); |
1da177e4 LT |
891 | } |
892 | ||
498f0103 | 893 | static struct priority_group *parse_priority_group(struct dm_arg_set *as, |
28f16c20 | 894 | struct multipath *m) |
1da177e4 | 895 | { |
498f0103 | 896 | static struct dm_arg _args[] = { |
72d94861 AK |
897 | {1, 1024, "invalid number of paths"}, |
898 | {0, 1024, "invalid number of selector args"} | |
1da177e4 LT |
899 | }; |
900 | ||
901 | int r; | |
498f0103 | 902 | unsigned i, nr_selector_args, nr_args; |
1da177e4 | 903 | struct priority_group *pg; |
28f16c20 | 904 | struct dm_target *ti = m->ti; |
1da177e4 LT |
905 | |
906 | if (as->argc < 2) { | |
907 | as->argc = 0; | |
01460f35 BM |
908 | ti->error = "not enough priority group arguments"; |
909 | return ERR_PTR(-EINVAL); | |
1da177e4 LT |
910 | } |
911 | ||
912 | pg = alloc_priority_group(); | |
913 | if (!pg) { | |
72d94861 | 914 | ti->error = "couldn't allocate priority group"; |
01460f35 | 915 | return ERR_PTR(-ENOMEM); |
1da177e4 LT |
916 | } |
917 | pg->m = m; | |
918 | ||
919 | r = parse_path_selector(as, pg, ti); | |
920 | if (r) | |
921 | goto bad; | |
922 | ||
923 | /* | |
924 | * read the paths | |
925 | */ | |
498f0103 | 926 | r = dm_read_arg(_args, as, &pg->nr_pgpaths, &ti->error); |
1da177e4 LT |
927 | if (r) |
928 | goto bad; | |
929 | ||
498f0103 | 930 | r = dm_read_arg(_args + 1, as, &nr_selector_args, &ti->error); |
1da177e4 LT |
931 | if (r) |
932 | goto bad; | |
933 | ||
498f0103 | 934 | nr_args = 1 + nr_selector_args; |
1da177e4 LT |
935 | for (i = 0; i < pg->nr_pgpaths; i++) { |
936 | struct pgpath *pgpath; | |
498f0103 | 937 | struct dm_arg_set path_args; |
1da177e4 | 938 | |
498f0103 | 939 | if (as->argc < nr_args) { |
148acff6 | 940 | ti->error = "not enough path parameters"; |
6bbf79a1 | 941 | r = -EINVAL; |
1da177e4 | 942 | goto bad; |
148acff6 | 943 | } |
1da177e4 | 944 | |
498f0103 | 945 | path_args.argc = nr_args; |
1da177e4 LT |
946 | path_args.argv = as->argv; |
947 | ||
948 | pgpath = parse_path(&path_args, &pg->ps, ti); | |
01460f35 BM |
949 | if (IS_ERR(pgpath)) { |
950 | r = PTR_ERR(pgpath); | |
1da177e4 | 951 | goto bad; |
01460f35 | 952 | } |
1da177e4 LT |
953 | |
954 | pgpath->pg = pg; | |
955 | list_add_tail(&pgpath->list, &pg->pgpaths); | |
498f0103 | 956 | dm_consume_args(as, nr_args); |
1da177e4 LT |
957 | } |
958 | ||
959 | return pg; | |
960 | ||
961 | bad: | |
962 | free_priority_group(pg, ti); | |
01460f35 | 963 | return ERR_PTR(r); |
1da177e4 LT |
964 | } |
965 | ||
498f0103 | 966 | static int parse_hw_handler(struct dm_arg_set *as, struct multipath *m) |
1da177e4 | 967 | { |
1da177e4 | 968 | unsigned hw_argc; |
2bfd2e13 | 969 | int ret; |
28f16c20 | 970 | struct dm_target *ti = m->ti; |
1da177e4 | 971 | |
498f0103 | 972 | static struct dm_arg _args[] = { |
72d94861 | 973 | {0, 1024, "invalid number of hardware handler args"}, |
1da177e4 LT |
974 | }; |
975 | ||
498f0103 | 976 | if (dm_read_arg_group(_args, as, &hw_argc, &ti->error)) |
1da177e4 LT |
977 | return -EINVAL; |
978 | ||
979 | if (!hw_argc) | |
980 | return 0; | |
981 | ||
e83068a5 | 982 | if (m->queue_mode == DM_TYPE_BIO_BASED) { |
76e33fe4 MS |
983 | dm_consume_args(as, hw_argc); |
984 | DMERR("bio-based multipath doesn't allow hardware handler args"); | |
985 | return 0; | |
986 | } | |
987 | ||
498f0103 | 988 | m->hw_handler_name = kstrdup(dm_shift_arg(as), GFP_KERNEL); |
14e98c5c | 989 | |
2bfd2e13 CS |
990 | if (hw_argc > 1) { |
991 | char *p; | |
992 | int i, j, len = 4; | |
993 | ||
994 | for (i = 0; i <= hw_argc - 2; i++) | |
995 | len += strlen(as->argv[i]) + 1; | |
996 | p = m->hw_handler_params = kzalloc(len, GFP_KERNEL); | |
997 | if (!p) { | |
998 | ti->error = "memory allocation failed"; | |
999 | ret = -ENOMEM; | |
1000 | goto fail; | |
1001 | } | |
1002 | j = sprintf(p, "%d", hw_argc - 1); | |
1003 | for (i = 0, p+=j+1; i <= hw_argc - 2; i++, p+=j+1) | |
1004 | j = sprintf(p, "%s", as->argv[i]); | |
1005 | } | |
498f0103 | 1006 | dm_consume_args(as, hw_argc - 1); |
1da177e4 LT |
1007 | |
1008 | return 0; | |
2bfd2e13 CS |
1009 | fail: |
1010 | kfree(m->hw_handler_name); | |
1011 | m->hw_handler_name = NULL; | |
1012 | return ret; | |
1da177e4 LT |
1013 | } |
1014 | ||
498f0103 | 1015 | static int parse_features(struct dm_arg_set *as, struct multipath *m) |
1da177e4 LT |
1016 | { |
1017 | int r; | |
1018 | unsigned argc; | |
28f16c20 | 1019 | struct dm_target *ti = m->ti; |
498f0103 | 1020 | const char *arg_name; |
1da177e4 | 1021 | |
498f0103 | 1022 | static struct dm_arg _args[] = { |
e83068a5 | 1023 | {0, 8, "invalid number of feature args"}, |
c9e45581 | 1024 | {1, 50, "pg_init_retries must be between 1 and 50"}, |
4e2d19e4 | 1025 | {0, 60000, "pg_init_delay_msecs must be between 0 and 60000"}, |
1da177e4 LT |
1026 | }; |
1027 | ||
498f0103 | 1028 | r = dm_read_arg_group(_args, as, &argc, &ti->error); |
1da177e4 LT |
1029 | if (r) |
1030 | return -EINVAL; | |
1031 | ||
1032 | if (!argc) | |
1033 | return 0; | |
1034 | ||
c9e45581 | 1035 | do { |
498f0103 | 1036 | arg_name = dm_shift_arg(as); |
c9e45581 DW |
1037 | argc--; |
1038 | ||
498f0103 | 1039 | if (!strcasecmp(arg_name, "queue_if_no_path")) { |
be7d31cc | 1040 | r = queue_if_no_path(m, true, false); |
c9e45581 DW |
1041 | continue; |
1042 | } | |
1043 | ||
a58a935d | 1044 | if (!strcasecmp(arg_name, "retain_attached_hw_handler")) { |
518257b1 | 1045 | set_bit(MPATHF_RETAIN_ATTACHED_HW_HANDLER, &m->flags); |
a58a935d MS |
1046 | continue; |
1047 | } | |
1048 | ||
498f0103 | 1049 | if (!strcasecmp(arg_name, "pg_init_retries") && |
c9e45581 | 1050 | (argc >= 1)) { |
498f0103 | 1051 | r = dm_read_arg(_args + 1, as, &m->pg_init_retries, &ti->error); |
c9e45581 DW |
1052 | argc--; |
1053 | continue; | |
1054 | } | |
1055 | ||
498f0103 | 1056 | if (!strcasecmp(arg_name, "pg_init_delay_msecs") && |
4e2d19e4 | 1057 | (argc >= 1)) { |
498f0103 | 1058 | r = dm_read_arg(_args + 2, as, &m->pg_init_delay_msecs, &ti->error); |
4e2d19e4 CS |
1059 | argc--; |
1060 | continue; | |
1061 | } | |
1062 | ||
e83068a5 MS |
1063 | if (!strcasecmp(arg_name, "queue_mode") && |
1064 | (argc >= 1)) { | |
1065 | const char *queue_mode_name = dm_shift_arg(as); | |
1066 | ||
1067 | if (!strcasecmp(queue_mode_name, "bio")) | |
1068 | m->queue_mode = DM_TYPE_BIO_BASED; | |
1069 | else if (!strcasecmp(queue_mode_name, "rq")) | |
1070 | m->queue_mode = DM_TYPE_REQUEST_BASED; | |
1071 | else if (!strcasecmp(queue_mode_name, "mq")) | |
1072 | m->queue_mode = DM_TYPE_MQ_REQUEST_BASED; | |
1073 | else { | |
1074 | ti->error = "Unknown 'queue_mode' requested"; | |
1075 | r = -EINVAL; | |
1076 | } | |
1077 | argc--; | |
1078 | continue; | |
1079 | } | |
1080 | ||
1da177e4 | 1081 | ti->error = "Unrecognised multipath feature request"; |
c9e45581 DW |
1082 | r = -EINVAL; |
1083 | } while (argc && !r); | |
1084 | ||
1085 | return r; | |
1da177e4 LT |
1086 | } |
1087 | ||
e83068a5 | 1088 | static int multipath_ctr(struct dm_target *ti, unsigned argc, char **argv) |
1da177e4 | 1089 | { |
498f0103 MS |
1090 | /* target arguments */ |
1091 | static struct dm_arg _args[] = { | |
a490a07a MS |
1092 | {0, 1024, "invalid number of priority groups"}, |
1093 | {0, 1024, "invalid initial priority group number"}, | |
1da177e4 LT |
1094 | }; |
1095 | ||
1096 | int r; | |
1097 | struct multipath *m; | |
498f0103 | 1098 | struct dm_arg_set as; |
1da177e4 LT |
1099 | unsigned pg_count = 0; |
1100 | unsigned next_pg_num; | |
1101 | ||
1102 | as.argc = argc; | |
1103 | as.argv = argv; | |
1104 | ||
e83068a5 | 1105 | m = alloc_multipath(ti); |
1da177e4 | 1106 | if (!m) { |
72d94861 | 1107 | ti->error = "can't allocate multipath"; |
1da177e4 LT |
1108 | return -EINVAL; |
1109 | } | |
1110 | ||
28f16c20 | 1111 | r = parse_features(&as, m); |
1da177e4 LT |
1112 | if (r) |
1113 | goto bad; | |
1114 | ||
e83068a5 MS |
1115 | r = alloc_multipath_stage2(ti, m); |
1116 | if (r) | |
1117 | goto bad; | |
1118 | ||
28f16c20 | 1119 | r = parse_hw_handler(&as, m); |
1da177e4 LT |
1120 | if (r) |
1121 | goto bad; | |
1122 | ||
498f0103 | 1123 | r = dm_read_arg(_args, &as, &m->nr_priority_groups, &ti->error); |
1da177e4 LT |
1124 | if (r) |
1125 | goto bad; | |
1126 | ||
498f0103 | 1127 | r = dm_read_arg(_args + 1, &as, &next_pg_num, &ti->error); |
1da177e4 LT |
1128 | if (r) |
1129 | goto bad; | |
1130 | ||
a490a07a MS |
1131 | if ((!m->nr_priority_groups && next_pg_num) || |
1132 | (m->nr_priority_groups && !next_pg_num)) { | |
1133 | ti->error = "invalid initial priority group"; | |
1134 | r = -EINVAL; | |
1135 | goto bad; | |
1136 | } | |
1137 | ||
1da177e4 LT |
1138 | /* parse the priority groups */ |
1139 | while (as.argc) { | |
1140 | struct priority_group *pg; | |
91e968aa | 1141 | unsigned nr_valid_paths = atomic_read(&m->nr_valid_paths); |
1da177e4 | 1142 | |
28f16c20 | 1143 | pg = parse_priority_group(&as, m); |
01460f35 BM |
1144 | if (IS_ERR(pg)) { |
1145 | r = PTR_ERR(pg); | |
1da177e4 LT |
1146 | goto bad; |
1147 | } | |
1148 | ||
91e968aa MS |
1149 | nr_valid_paths += pg->nr_pgpaths; |
1150 | atomic_set(&m->nr_valid_paths, nr_valid_paths); | |
1151 | ||
1da177e4 LT |
1152 | list_add_tail(&pg->list, &m->priority_groups); |
1153 | pg_count++; | |
1154 | pg->pg_num = pg_count; | |
1155 | if (!--next_pg_num) | |
1156 | m->next_pg = pg; | |
1157 | } | |
1158 | ||
1159 | if (pg_count != m->nr_priority_groups) { | |
72d94861 | 1160 | ti->error = "priority group count mismatch"; |
1da177e4 LT |
1161 | r = -EINVAL; |
1162 | goto bad; | |
1163 | } | |
1164 | ||
55a62eef AK |
1165 | ti->num_flush_bios = 1; |
1166 | ti->num_discard_bios = 1; | |
042bcef8 | 1167 | ti->num_write_same_bios = 1; |
e83068a5 | 1168 | if (m->queue_mode == DM_TYPE_BIO_BASED) |
bf661be1 | 1169 | ti->per_io_data_size = multipath_per_bio_data_size(); |
e83068a5 | 1170 | else if (m->queue_mode == DM_TYPE_MQ_REQUEST_BASED) |
8637a6bf | 1171 | ti->per_io_data_size = sizeof(struct dm_mpath_io); |
8627921f | 1172 | |
1da177e4 LT |
1173 | return 0; |
1174 | ||
1175 | bad: | |
1176 | free_multipath(m); | |
1177 | return r; | |
1178 | } | |
1179 | ||
2bded7bd KU |
1180 | static void multipath_wait_for_pg_init_completion(struct multipath *m) |
1181 | { | |
1182 | DECLARE_WAITQUEUE(wait, current); | |
2bded7bd KU |
1183 | |
1184 | add_wait_queue(&m->pg_init_wait, &wait); | |
1185 | ||
1186 | while (1) { | |
1187 | set_current_state(TASK_UNINTERRUPTIBLE); | |
1188 | ||
91e968aa | 1189 | if (!atomic_read(&m->pg_init_in_progress)) |
2bded7bd | 1190 | break; |
2bded7bd KU |
1191 | |
1192 | io_schedule(); | |
1193 | } | |
1194 | set_current_state(TASK_RUNNING); | |
1195 | ||
1196 | remove_wait_queue(&m->pg_init_wait, &wait); | |
1197 | } | |
1198 | ||
1199 | static void flush_multipath_work(struct multipath *m) | |
1da177e4 | 1200 | { |
518257b1 MS |
1201 | set_bit(MPATHF_PG_INIT_DISABLED, &m->flags); |
1202 | smp_mb__after_atomic(); | |
954a73d5 | 1203 | |
bab7cfc7 | 1204 | flush_workqueue(kmpath_handlerd); |
2bded7bd | 1205 | multipath_wait_for_pg_init_completion(m); |
a044d016 | 1206 | flush_workqueue(kmultipathd); |
43829731 | 1207 | flush_work(&m->trigger_event); |
954a73d5 | 1208 | |
518257b1 MS |
1209 | clear_bit(MPATHF_PG_INIT_DISABLED, &m->flags); |
1210 | smp_mb__after_atomic(); | |
6df400ab KU |
1211 | } |
1212 | ||
1213 | static void multipath_dtr(struct dm_target *ti) | |
1214 | { | |
1215 | struct multipath *m = ti->private; | |
1216 | ||
2bded7bd | 1217 | flush_multipath_work(m); |
1da177e4 LT |
1218 | free_multipath(m); |
1219 | } | |
1220 | ||
1da177e4 LT |
1221 | /* |
1222 | * Take a path out of use. | |
1223 | */ | |
1224 | static int fail_path(struct pgpath *pgpath) | |
1225 | { | |
1226 | unsigned long flags; | |
1227 | struct multipath *m = pgpath->pg->m; | |
1228 | ||
1229 | spin_lock_irqsave(&m->lock, flags); | |
1230 | ||
6680073d | 1231 | if (!pgpath->is_active) |
1da177e4 LT |
1232 | goto out; |
1233 | ||
72d94861 | 1234 | DMWARN("Failing path %s.", pgpath->path.dev->name); |
1da177e4 LT |
1235 | |
1236 | pgpath->pg->ps.type->fail_path(&pgpath->pg->ps, &pgpath->path); | |
be7d31cc | 1237 | pgpath->is_active = false; |
1da177e4 LT |
1238 | pgpath->fail_count++; |
1239 | ||
91e968aa | 1240 | atomic_dec(&m->nr_valid_paths); |
1da177e4 LT |
1241 | |
1242 | if (pgpath == m->current_pgpath) | |
1243 | m->current_pgpath = NULL; | |
1244 | ||
b15546f9 | 1245 | dm_path_uevent(DM_UEVENT_PATH_FAILED, m->ti, |
91e968aa | 1246 | pgpath->path.dev->name, atomic_read(&m->nr_valid_paths)); |
b15546f9 | 1247 | |
fe9cf30e | 1248 | schedule_work(&m->trigger_event); |
1da177e4 LT |
1249 | |
1250 | out: | |
1251 | spin_unlock_irqrestore(&m->lock, flags); | |
1252 | ||
1253 | return 0; | |
1254 | } | |
1255 | ||
1256 | /* | |
1257 | * Reinstate a previously-failed path | |
1258 | */ | |
1259 | static int reinstate_path(struct pgpath *pgpath) | |
1260 | { | |
63d832c3 | 1261 | int r = 0, run_queue = 0; |
1da177e4 LT |
1262 | unsigned long flags; |
1263 | struct multipath *m = pgpath->pg->m; | |
91e968aa | 1264 | unsigned nr_valid_paths; |
1da177e4 LT |
1265 | |
1266 | spin_lock_irqsave(&m->lock, flags); | |
1267 | ||
6680073d | 1268 | if (pgpath->is_active) |
1da177e4 LT |
1269 | goto out; |
1270 | ||
ec31f3f7 | 1271 | DMWARN("Reinstating path %s.", pgpath->path.dev->name); |
1da177e4 LT |
1272 | |
1273 | r = pgpath->pg->ps.type->reinstate_path(&pgpath->pg->ps, &pgpath->path); | |
1274 | if (r) | |
1275 | goto out; | |
1276 | ||
be7d31cc | 1277 | pgpath->is_active = true; |
1da177e4 | 1278 | |
91e968aa MS |
1279 | nr_valid_paths = atomic_inc_return(&m->nr_valid_paths); |
1280 | if (nr_valid_paths == 1) { | |
e54f77dd | 1281 | m->current_pgpath = NULL; |
63d832c3 | 1282 | run_queue = 1; |
e54f77dd | 1283 | } else if (m->hw_handler_name && (m->current_pg == pgpath->pg)) { |
4e2d19e4 | 1284 | if (queue_work(kmpath_handlerd, &pgpath->activate_path.work)) |
91e968aa | 1285 | atomic_inc(&m->pg_init_in_progress); |
e54f77dd | 1286 | } |
1da177e4 | 1287 | |
b15546f9 | 1288 | dm_path_uevent(DM_UEVENT_PATH_REINSTATED, m->ti, |
91e968aa | 1289 | pgpath->path.dev->name, nr_valid_paths); |
b15546f9 | 1290 | |
fe9cf30e | 1291 | schedule_work(&m->trigger_event); |
1da177e4 LT |
1292 | |
1293 | out: | |
1294 | spin_unlock_irqrestore(&m->lock, flags); | |
76e33fe4 | 1295 | if (run_queue) { |
63d832c3 | 1296 | dm_table_run_md_queue_async(m->ti->table); |
76e33fe4 MS |
1297 | process_queued_bios_list(m); |
1298 | } | |
1da177e4 LT |
1299 | |
1300 | return r; | |
1301 | } | |
1302 | ||
1303 | /* | |
1304 | * Fail or reinstate all paths that match the provided struct dm_dev. | |
1305 | */ | |
1306 | static int action_dev(struct multipath *m, struct dm_dev *dev, | |
1307 | action_fn action) | |
1308 | { | |
19040c0b | 1309 | int r = -EINVAL; |
1da177e4 LT |
1310 | struct pgpath *pgpath; |
1311 | struct priority_group *pg; | |
1312 | ||
1313 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1314 | list_for_each_entry(pgpath, &pg->pgpaths, list) { | |
1315 | if (pgpath->path.dev == dev) | |
1316 | r = action(pgpath); | |
1317 | } | |
1318 | } | |
1319 | ||
1320 | return r; | |
1321 | } | |
1322 | ||
1323 | /* | |
1324 | * Temporarily try to avoid having to use the specified PG | |
1325 | */ | |
1326 | static void bypass_pg(struct multipath *m, struct priority_group *pg, | |
be7d31cc | 1327 | bool bypassed) |
1da177e4 LT |
1328 | { |
1329 | unsigned long flags; | |
1330 | ||
1331 | spin_lock_irqsave(&m->lock, flags); | |
1332 | ||
1333 | pg->bypassed = bypassed; | |
1334 | m->current_pgpath = NULL; | |
1335 | m->current_pg = NULL; | |
1336 | ||
1337 | spin_unlock_irqrestore(&m->lock, flags); | |
1338 | ||
fe9cf30e | 1339 | schedule_work(&m->trigger_event); |
1da177e4 LT |
1340 | } |
1341 | ||
1342 | /* | |
1343 | * Switch to using the specified PG from the next I/O that gets mapped | |
1344 | */ | |
1345 | static int switch_pg_num(struct multipath *m, const char *pgstr) | |
1346 | { | |
1347 | struct priority_group *pg; | |
1348 | unsigned pgnum; | |
1349 | unsigned long flags; | |
31998ef1 | 1350 | char dummy; |
1da177e4 | 1351 | |
31998ef1 | 1352 | if (!pgstr || (sscanf(pgstr, "%u%c", &pgnum, &dummy) != 1) || !pgnum || |
1da177e4 LT |
1353 | (pgnum > m->nr_priority_groups)) { |
1354 | DMWARN("invalid PG number supplied to switch_pg_num"); | |
1355 | return -EINVAL; | |
1356 | } | |
1357 | ||
1358 | spin_lock_irqsave(&m->lock, flags); | |
1359 | list_for_each_entry(pg, &m->priority_groups, list) { | |
be7d31cc | 1360 | pg->bypassed = false; |
1da177e4 LT |
1361 | if (--pgnum) |
1362 | continue; | |
1363 | ||
1364 | m->current_pgpath = NULL; | |
1365 | m->current_pg = NULL; | |
1366 | m->next_pg = pg; | |
1367 | } | |
1368 | spin_unlock_irqrestore(&m->lock, flags); | |
1369 | ||
fe9cf30e | 1370 | schedule_work(&m->trigger_event); |
1da177e4 LT |
1371 | return 0; |
1372 | } | |
1373 | ||
1374 | /* | |
1375 | * Set/clear bypassed status of a PG. | |
1376 | * PGs are numbered upwards from 1 in the order they were declared. | |
1377 | */ | |
be7d31cc | 1378 | static int bypass_pg_num(struct multipath *m, const char *pgstr, bool bypassed) |
1da177e4 LT |
1379 | { |
1380 | struct priority_group *pg; | |
1381 | unsigned pgnum; | |
31998ef1 | 1382 | char dummy; |
1da177e4 | 1383 | |
31998ef1 | 1384 | if (!pgstr || (sscanf(pgstr, "%u%c", &pgnum, &dummy) != 1) || !pgnum || |
1da177e4 LT |
1385 | (pgnum > m->nr_priority_groups)) { |
1386 | DMWARN("invalid PG number supplied to bypass_pg"); | |
1387 | return -EINVAL; | |
1388 | } | |
1389 | ||
1390 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1391 | if (!--pgnum) | |
1392 | break; | |
1393 | } | |
1394 | ||
1395 | bypass_pg(m, pg, bypassed); | |
1396 | return 0; | |
1397 | } | |
1398 | ||
c9e45581 DW |
1399 | /* |
1400 | * Should we retry pg_init immediately? | |
1401 | */ | |
be7d31cc | 1402 | static bool pg_init_limit_reached(struct multipath *m, struct pgpath *pgpath) |
c9e45581 DW |
1403 | { |
1404 | unsigned long flags; | |
be7d31cc | 1405 | bool limit_reached = false; |
c9e45581 DW |
1406 | |
1407 | spin_lock_irqsave(&m->lock, flags); | |
1408 | ||
91e968aa MS |
1409 | if (atomic_read(&m->pg_init_count) <= m->pg_init_retries && |
1410 | !test_bit(MPATHF_PG_INIT_DISABLED, &m->flags)) | |
518257b1 | 1411 | set_bit(MPATHF_PG_INIT_REQUIRED, &m->flags); |
c9e45581 | 1412 | else |
be7d31cc | 1413 | limit_reached = true; |
c9e45581 DW |
1414 | |
1415 | spin_unlock_irqrestore(&m->lock, flags); | |
1416 | ||
1417 | return limit_reached; | |
1418 | } | |
1419 | ||
3ae31f6a | 1420 | static void pg_init_done(void *data, int errors) |
cfae5c9b | 1421 | { |
83c0d5d5 | 1422 | struct pgpath *pgpath = data; |
cfae5c9b CS |
1423 | struct priority_group *pg = pgpath->pg; |
1424 | struct multipath *m = pg->m; | |
1425 | unsigned long flags; | |
be7d31cc | 1426 | bool delay_retry = false; |
cfae5c9b CS |
1427 | |
1428 | /* device or driver problems */ | |
1429 | switch (errors) { | |
1430 | case SCSI_DH_OK: | |
1431 | break; | |
1432 | case SCSI_DH_NOSYS: | |
1433 | if (!m->hw_handler_name) { | |
1434 | errors = 0; | |
1435 | break; | |
1436 | } | |
f7b934c8 MB |
1437 | DMERR("Could not failover the device: Handler scsi_dh_%s " |
1438 | "Error %d.", m->hw_handler_name, errors); | |
cfae5c9b CS |
1439 | /* |
1440 | * Fail path for now, so we do not ping pong | |
1441 | */ | |
1442 | fail_path(pgpath); | |
1443 | break; | |
1444 | case SCSI_DH_DEV_TEMP_BUSY: | |
1445 | /* | |
1446 | * Probably doing something like FW upgrade on the | |
1447 | * controller so try the other pg. | |
1448 | */ | |
be7d31cc | 1449 | bypass_pg(m, pg, true); |
cfae5c9b | 1450 | break; |
cfae5c9b | 1451 | case SCSI_DH_RETRY: |
4e2d19e4 CS |
1452 | /* Wait before retrying. */ |
1453 | delay_retry = 1; | |
cfae5c9b CS |
1454 | case SCSI_DH_IMM_RETRY: |
1455 | case SCSI_DH_RES_TEMP_UNAVAIL: | |
1456 | if (pg_init_limit_reached(m, pgpath)) | |
1457 | fail_path(pgpath); | |
1458 | errors = 0; | |
1459 | break; | |
ec31f3f7 | 1460 | case SCSI_DH_DEV_OFFLINED: |
cfae5c9b CS |
1461 | default: |
1462 | /* | |
1463 | * We probably do not want to fail the path for a device | |
1464 | * error, but this is what the old dm did. In future | |
1465 | * patches we can do more advanced handling. | |
1466 | */ | |
1467 | fail_path(pgpath); | |
1468 | } | |
1469 | ||
1470 | spin_lock_irqsave(&m->lock, flags); | |
1471 | if (errors) { | |
e54f77dd CS |
1472 | if (pgpath == m->current_pgpath) { |
1473 | DMERR("Could not failover device. Error %d.", errors); | |
1474 | m->current_pgpath = NULL; | |
1475 | m->current_pg = NULL; | |
1476 | } | |
518257b1 | 1477 | } else if (!test_bit(MPATHF_PG_INIT_REQUIRED, &m->flags)) |
be7d31cc | 1478 | pg->bypassed = false; |
cfae5c9b | 1479 | |
91e968aa | 1480 | if (atomic_dec_return(&m->pg_init_in_progress) > 0) |
d0259bf0 KU |
1481 | /* Activations of other paths are still on going */ |
1482 | goto out; | |
1483 | ||
518257b1 MS |
1484 | if (test_bit(MPATHF_PG_INIT_REQUIRED, &m->flags)) { |
1485 | if (delay_retry) | |
1486 | set_bit(MPATHF_PG_INIT_DELAY_RETRY, &m->flags); | |
1487 | else | |
1488 | clear_bit(MPATHF_PG_INIT_DELAY_RETRY, &m->flags); | |
1489 | ||
3e9f1be1 HR |
1490 | if (__pg_init_all_paths(m)) |
1491 | goto out; | |
1492 | } | |
518257b1 | 1493 | clear_bit(MPATHF_QUEUE_IO, &m->flags); |
d0259bf0 | 1494 | |
76e33fe4 MS |
1495 | process_queued_bios_list(m); |
1496 | ||
2bded7bd KU |
1497 | /* |
1498 | * Wake up any thread waiting to suspend. | |
1499 | */ | |
1500 | wake_up(&m->pg_init_wait); | |
1501 | ||
d0259bf0 | 1502 | out: |
cfae5c9b CS |
1503 | spin_unlock_irqrestore(&m->lock, flags); |
1504 | } | |
1505 | ||
bab7cfc7 CS |
1506 | static void activate_path(struct work_struct *work) |
1507 | { | |
e54f77dd | 1508 | struct pgpath *pgpath = |
4e2d19e4 | 1509 | container_of(work, struct pgpath, activate_path.work); |
bab7cfc7 | 1510 | |
3a017509 HR |
1511 | if (pgpath->is_active) |
1512 | scsi_dh_activate(bdev_get_queue(pgpath->path.dev->bdev), | |
1513 | pg_init_done, pgpath); | |
1514 | else | |
1515 | pg_init_done(pgpath, SCSI_DH_DEV_OFFLINED); | |
bab7cfc7 CS |
1516 | } |
1517 | ||
7e782af5 HR |
1518 | static int noretry_error(int error) |
1519 | { | |
1520 | switch (error) { | |
1521 | case -EOPNOTSUPP: | |
1522 | case -EREMOTEIO: | |
1523 | case -EILSEQ: | |
1524 | case -ENODATA: | |
cc9d3c38 | 1525 | case -ENOSPC: |
7e782af5 HR |
1526 | return 1; |
1527 | } | |
1528 | ||
1529 | /* Anything else could be a path failure, so should be retried */ | |
1530 | return 0; | |
1531 | } | |
1532 | ||
1da177e4 LT |
1533 | /* |
1534 | * end_io handling | |
1535 | */ | |
f40c67f0 | 1536 | static int do_end_io(struct multipath *m, struct request *clone, |
028867ac | 1537 | int error, struct dm_mpath_io *mpio) |
1da177e4 | 1538 | { |
f40c67f0 KU |
1539 | /* |
1540 | * We don't queue any clone request inside the multipath target | |
1541 | * during end I/O handling, since those clone requests don't have | |
1542 | * bio clones. If we queue them inside the multipath target, | |
1543 | * we need to make bio clones, that requires memory allocation. | |
4cc96131 | 1544 | * (See drivers/md/dm-rq.c:end_clone_bio() about why the clone requests |
f40c67f0 KU |
1545 | * don't have bio clones.) |
1546 | * Instead of queueing the clone request here, we queue the original | |
1547 | * request into dm core, which will remake a clone request and | |
1548 | * clone bios for it and resubmit it later. | |
1549 | */ | |
1550 | int r = DM_ENDIO_REQUEUE; | |
1da177e4 | 1551 | |
f40c67f0 | 1552 | if (!error && !clone->errors) |
1da177e4 LT |
1553 | return 0; /* I/O complete */ |
1554 | ||
7eee4ae2 | 1555 | if (noretry_error(error)) |
959eb4e5 MS |
1556 | return error; |
1557 | ||
cfae5c9b CS |
1558 | if (mpio->pgpath) |
1559 | fail_path(mpio->pgpath); | |
1da177e4 | 1560 | |
91e968aa | 1561 | if (!atomic_read(&m->nr_valid_paths)) { |
518257b1 | 1562 | if (!test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) { |
76e33fe4 | 1563 | if (!must_push_back_rq(m)) |
751b2a7d HR |
1564 | r = -EIO; |
1565 | } else { | |
1566 | if (error == -EBADE) | |
1567 | r = error; | |
1568 | } | |
1569 | } | |
1da177e4 | 1570 | |
f40c67f0 | 1571 | return r; |
1da177e4 LT |
1572 | } |
1573 | ||
f40c67f0 | 1574 | static int multipath_end_io(struct dm_target *ti, struct request *clone, |
1da177e4 LT |
1575 | int error, union map_info *map_context) |
1576 | { | |
028867ac | 1577 | struct multipath *m = ti->private; |
2eff1924 | 1578 | struct dm_mpath_io *mpio = get_mpio(map_context); |
a71a261f | 1579 | struct pgpath *pgpath; |
1da177e4 LT |
1580 | struct path_selector *ps; |
1581 | int r; | |
1582 | ||
466891f9 JN |
1583 | BUG_ON(!mpio); |
1584 | ||
2eff1924 | 1585 | r = do_end_io(m, clone, error, mpio); |
a71a261f | 1586 | pgpath = mpio->pgpath; |
1da177e4 LT |
1587 | if (pgpath) { |
1588 | ps = &pgpath->pg->ps; | |
1589 | if (ps->type->end_io) | |
02ab823f | 1590 | ps->type->end_io(ps, &pgpath->path, mpio->nr_bytes); |
1da177e4 | 1591 | } |
2eff1924 | 1592 | clear_request_fn_mpio(m, map_context); |
1da177e4 LT |
1593 | |
1594 | return r; | |
1595 | } | |
1596 | ||
76e33fe4 MS |
1597 | static int do_end_io_bio(struct multipath *m, struct bio *clone, |
1598 | int error, struct dm_mpath_io *mpio) | |
1599 | { | |
1600 | unsigned long flags; | |
1601 | ||
1602 | if (!error) | |
1603 | return 0; /* I/O complete */ | |
1604 | ||
1605 | if (noretry_error(error)) | |
1606 | return error; | |
1607 | ||
1608 | if (mpio->pgpath) | |
1609 | fail_path(mpio->pgpath); | |
1610 | ||
1611 | if (!atomic_read(&m->nr_valid_paths)) { | |
1612 | if (!test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) { | |
1613 | if (!must_push_back_bio(m)) | |
1614 | return -EIO; | |
1615 | return DM_ENDIO_REQUEUE; | |
1616 | } else { | |
1617 | if (error == -EBADE) | |
1618 | return error; | |
1619 | } | |
1620 | } | |
1621 | ||
1622 | /* Queue for the daemon to resubmit */ | |
bf661be1 | 1623 | dm_bio_restore(get_bio_details_from_bio(clone), clone); |
76e33fe4 MS |
1624 | |
1625 | spin_lock_irqsave(&m->lock, flags); | |
1626 | bio_list_add(&m->queued_bios, clone); | |
1627 | spin_unlock_irqrestore(&m->lock, flags); | |
1628 | if (!test_bit(MPATHF_QUEUE_IO, &m->flags)) | |
1629 | queue_work(kmultipathd, &m->process_queued_bios); | |
1630 | ||
1631 | return DM_ENDIO_INCOMPLETE; | |
1632 | } | |
1633 | ||
1634 | static int multipath_end_io_bio(struct dm_target *ti, struct bio *clone, int error) | |
1635 | { | |
1636 | struct multipath *m = ti->private; | |
1637 | struct dm_mpath_io *mpio = get_mpio_from_bio(clone); | |
1638 | struct pgpath *pgpath; | |
1639 | struct path_selector *ps; | |
1640 | int r; | |
1641 | ||
1642 | BUG_ON(!mpio); | |
1643 | ||
1644 | r = do_end_io_bio(m, clone, error, mpio); | |
1645 | pgpath = mpio->pgpath; | |
1646 | if (pgpath) { | |
1647 | ps = &pgpath->pg->ps; | |
1648 | if (ps->type->end_io) | |
1649 | ps->type->end_io(ps, &pgpath->path, mpio->nr_bytes); | |
1650 | } | |
1651 | ||
1652 | return r; | |
1653 | } | |
1654 | ||
1da177e4 LT |
1655 | /* |
1656 | * Suspend can't complete until all the I/O is processed so if | |
436d4108 AK |
1657 | * the last path fails we must error any remaining I/O. |
1658 | * Note that if the freeze_bdev fails while suspending, the | |
1659 | * queue_if_no_path state is lost - userspace should reset it. | |
1da177e4 LT |
1660 | */ |
1661 | static void multipath_presuspend(struct dm_target *ti) | |
1662 | { | |
7943bd6d | 1663 | struct multipath *m = ti->private; |
1da177e4 | 1664 | |
be7d31cc | 1665 | queue_if_no_path(m, false, true); |
1da177e4 LT |
1666 | } |
1667 | ||
6df400ab KU |
1668 | static void multipath_postsuspend(struct dm_target *ti) |
1669 | { | |
6380f26f MA |
1670 | struct multipath *m = ti->private; |
1671 | ||
1672 | mutex_lock(&m->work_mutex); | |
2bded7bd | 1673 | flush_multipath_work(m); |
6380f26f | 1674 | mutex_unlock(&m->work_mutex); |
6df400ab KU |
1675 | } |
1676 | ||
436d4108 AK |
1677 | /* |
1678 | * Restore the queue_if_no_path setting. | |
1679 | */ | |
1da177e4 LT |
1680 | static void multipath_resume(struct dm_target *ti) |
1681 | { | |
7943bd6d | 1682 | struct multipath *m = ti->private; |
1da177e4 | 1683 | |
518257b1 MS |
1684 | if (test_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &m->flags)) |
1685 | set_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags); | |
1686 | else | |
1687 | clear_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags); | |
1688 | smp_mb__after_atomic(); | |
1da177e4 LT |
1689 | } |
1690 | ||
1691 | /* | |
1692 | * Info output has the following format: | |
1693 | * num_multipath_feature_args [multipath_feature_args]* | |
1694 | * num_handler_status_args [handler_status_args]* | |
1695 | * num_groups init_group_number | |
1696 | * [A|D|E num_ps_status_args [ps_status_args]* | |
1697 | * num_paths num_selector_args | |
1698 | * [path_dev A|F fail_count [selector_args]* ]+ ]+ | |
1699 | * | |
1700 | * Table output has the following format (identical to the constructor string): | |
1701 | * num_feature_args [features_args]* | |
1702 | * num_handler_args hw_handler [hw_handler_args]* | |
1703 | * num_groups init_group_number | |
1704 | * [priority selector-name num_ps_args [ps_args]* | |
1705 | * num_paths num_selector_args [path_dev [selector_args]* ]+ ]+ | |
1706 | */ | |
fd7c092e MP |
1707 | static void multipath_status(struct dm_target *ti, status_type_t type, |
1708 | unsigned status_flags, char *result, unsigned maxlen) | |
1da177e4 LT |
1709 | { |
1710 | int sz = 0; | |
1711 | unsigned long flags; | |
7943bd6d | 1712 | struct multipath *m = ti->private; |
1da177e4 LT |
1713 | struct priority_group *pg; |
1714 | struct pgpath *p; | |
1715 | unsigned pg_num; | |
1716 | char state; | |
1717 | ||
1718 | spin_lock_irqsave(&m->lock, flags); | |
1719 | ||
1720 | /* Features */ | |
1721 | if (type == STATUSTYPE_INFO) | |
91e968aa MS |
1722 | DMEMIT("2 %u %u ", test_bit(MPATHF_QUEUE_IO, &m->flags), |
1723 | atomic_read(&m->pg_init_count)); | |
c9e45581 | 1724 | else { |
518257b1 | 1725 | DMEMIT("%u ", test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags) + |
4e2d19e4 | 1726 | (m->pg_init_retries > 0) * 2 + |
a58a935d | 1727 | (m->pg_init_delay_msecs != DM_PG_INIT_DELAY_DEFAULT) * 2 + |
e83068a5 MS |
1728 | test_bit(MPATHF_RETAIN_ATTACHED_HW_HANDLER, &m->flags) + |
1729 | (m->queue_mode != DM_TYPE_REQUEST_BASED) * 2); | |
1730 | ||
518257b1 | 1731 | if (test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) |
c9e45581 DW |
1732 | DMEMIT("queue_if_no_path "); |
1733 | if (m->pg_init_retries) | |
1734 | DMEMIT("pg_init_retries %u ", m->pg_init_retries); | |
4e2d19e4 CS |
1735 | if (m->pg_init_delay_msecs != DM_PG_INIT_DELAY_DEFAULT) |
1736 | DMEMIT("pg_init_delay_msecs %u ", m->pg_init_delay_msecs); | |
518257b1 | 1737 | if (test_bit(MPATHF_RETAIN_ATTACHED_HW_HANDLER, &m->flags)) |
a58a935d | 1738 | DMEMIT("retain_attached_hw_handler "); |
e83068a5 MS |
1739 | if (m->queue_mode != DM_TYPE_REQUEST_BASED) { |
1740 | switch(m->queue_mode) { | |
1741 | case DM_TYPE_BIO_BASED: | |
1742 | DMEMIT("queue_mode bio "); | |
1743 | break; | |
1744 | case DM_TYPE_MQ_REQUEST_BASED: | |
1745 | DMEMIT("queue_mode mq "); | |
1746 | break; | |
1747 | } | |
1748 | } | |
c9e45581 | 1749 | } |
1da177e4 | 1750 | |
cfae5c9b | 1751 | if (!m->hw_handler_name || type == STATUSTYPE_INFO) |
1da177e4 LT |
1752 | DMEMIT("0 "); |
1753 | else | |
cfae5c9b | 1754 | DMEMIT("1 %s ", m->hw_handler_name); |
1da177e4 LT |
1755 | |
1756 | DMEMIT("%u ", m->nr_priority_groups); | |
1757 | ||
1758 | if (m->next_pg) | |
1759 | pg_num = m->next_pg->pg_num; | |
1760 | else if (m->current_pg) | |
1761 | pg_num = m->current_pg->pg_num; | |
1762 | else | |
a490a07a | 1763 | pg_num = (m->nr_priority_groups ? 1 : 0); |
1da177e4 LT |
1764 | |
1765 | DMEMIT("%u ", pg_num); | |
1766 | ||
1767 | switch (type) { | |
1768 | case STATUSTYPE_INFO: | |
1769 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1770 | if (pg->bypassed) | |
1771 | state = 'D'; /* Disabled */ | |
1772 | else if (pg == m->current_pg) | |
1773 | state = 'A'; /* Currently Active */ | |
1774 | else | |
1775 | state = 'E'; /* Enabled */ | |
1776 | ||
1777 | DMEMIT("%c ", state); | |
1778 | ||
1779 | if (pg->ps.type->status) | |
1780 | sz += pg->ps.type->status(&pg->ps, NULL, type, | |
1781 | result + sz, | |
1782 | maxlen - sz); | |
1783 | else | |
1784 | DMEMIT("0 "); | |
1785 | ||
1786 | DMEMIT("%u %u ", pg->nr_pgpaths, | |
1787 | pg->ps.type->info_args); | |
1788 | ||
1789 | list_for_each_entry(p, &pg->pgpaths, list) { | |
1790 | DMEMIT("%s %s %u ", p->path.dev->name, | |
6680073d | 1791 | p->is_active ? "A" : "F", |
1da177e4 LT |
1792 | p->fail_count); |
1793 | if (pg->ps.type->status) | |
1794 | sz += pg->ps.type->status(&pg->ps, | |
1795 | &p->path, type, result + sz, | |
1796 | maxlen - sz); | |
1797 | } | |
1798 | } | |
1799 | break; | |
1800 | ||
1801 | case STATUSTYPE_TABLE: | |
1802 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1803 | DMEMIT("%s ", pg->ps.type->name); | |
1804 | ||
1805 | if (pg->ps.type->status) | |
1806 | sz += pg->ps.type->status(&pg->ps, NULL, type, | |
1807 | result + sz, | |
1808 | maxlen - sz); | |
1809 | else | |
1810 | DMEMIT("0 "); | |
1811 | ||
1812 | DMEMIT("%u %u ", pg->nr_pgpaths, | |
1813 | pg->ps.type->table_args); | |
1814 | ||
1815 | list_for_each_entry(p, &pg->pgpaths, list) { | |
1816 | DMEMIT("%s ", p->path.dev->name); | |
1817 | if (pg->ps.type->status) | |
1818 | sz += pg->ps.type->status(&pg->ps, | |
1819 | &p->path, type, result + sz, | |
1820 | maxlen - sz); | |
1821 | } | |
1822 | } | |
1823 | break; | |
1824 | } | |
1825 | ||
1826 | spin_unlock_irqrestore(&m->lock, flags); | |
1da177e4 LT |
1827 | } |
1828 | ||
1829 | static int multipath_message(struct dm_target *ti, unsigned argc, char **argv) | |
1830 | { | |
6380f26f | 1831 | int r = -EINVAL; |
1da177e4 | 1832 | struct dm_dev *dev; |
7943bd6d | 1833 | struct multipath *m = ti->private; |
1da177e4 LT |
1834 | action_fn action; |
1835 | ||
6380f26f MA |
1836 | mutex_lock(&m->work_mutex); |
1837 | ||
c2f3d24b KU |
1838 | if (dm_suspended(ti)) { |
1839 | r = -EBUSY; | |
1840 | goto out; | |
1841 | } | |
1842 | ||
1da177e4 | 1843 | if (argc == 1) { |
498f0103 | 1844 | if (!strcasecmp(argv[0], "queue_if_no_path")) { |
be7d31cc | 1845 | r = queue_if_no_path(m, true, false); |
6380f26f | 1846 | goto out; |
498f0103 | 1847 | } else if (!strcasecmp(argv[0], "fail_if_no_path")) { |
be7d31cc | 1848 | r = queue_if_no_path(m, false, false); |
6380f26f MA |
1849 | goto out; |
1850 | } | |
1da177e4 LT |
1851 | } |
1852 | ||
6380f26f | 1853 | if (argc != 2) { |
a356e426 | 1854 | DMWARN("Invalid multipath message arguments. Expected 2 arguments, got %d.", argc); |
6380f26f MA |
1855 | goto out; |
1856 | } | |
1da177e4 | 1857 | |
498f0103 | 1858 | if (!strcasecmp(argv[0], "disable_group")) { |
be7d31cc | 1859 | r = bypass_pg_num(m, argv[1], true); |
6380f26f | 1860 | goto out; |
498f0103 | 1861 | } else if (!strcasecmp(argv[0], "enable_group")) { |
be7d31cc | 1862 | r = bypass_pg_num(m, argv[1], false); |
6380f26f | 1863 | goto out; |
498f0103 | 1864 | } else if (!strcasecmp(argv[0], "switch_group")) { |
6380f26f MA |
1865 | r = switch_pg_num(m, argv[1]); |
1866 | goto out; | |
498f0103 | 1867 | } else if (!strcasecmp(argv[0], "reinstate_path")) |
1da177e4 | 1868 | action = reinstate_path; |
498f0103 | 1869 | else if (!strcasecmp(argv[0], "fail_path")) |
1da177e4 | 1870 | action = fail_path; |
6380f26f | 1871 | else { |
a356e426 | 1872 | DMWARN("Unrecognised multipath message received: %s", argv[0]); |
6380f26f MA |
1873 | goto out; |
1874 | } | |
1da177e4 | 1875 | |
8215d6ec | 1876 | r = dm_get_device(ti, argv[1], dm_table_get_mode(ti->table), &dev); |
1da177e4 | 1877 | if (r) { |
72d94861 | 1878 | DMWARN("message: error getting device %s", |
1da177e4 | 1879 | argv[1]); |
6380f26f | 1880 | goto out; |
1da177e4 LT |
1881 | } |
1882 | ||
1883 | r = action_dev(m, dev, action); | |
1884 | ||
1885 | dm_put_device(ti, dev); | |
1886 | ||
6380f26f MA |
1887 | out: |
1888 | mutex_unlock(&m->work_mutex); | |
1da177e4 | 1889 | return r; |
1da177e4 LT |
1890 | } |
1891 | ||
e56f81e0 CH |
1892 | static int multipath_prepare_ioctl(struct dm_target *ti, |
1893 | struct block_device **bdev, fmode_t *mode) | |
9af4aa30 | 1894 | { |
35991652 | 1895 | struct multipath *m = ti->private; |
2da1610a | 1896 | struct pgpath *current_pgpath; |
35991652 MP |
1897 | int r; |
1898 | ||
2da1610a MS |
1899 | current_pgpath = lockless_dereference(m->current_pgpath); |
1900 | if (!current_pgpath) | |
1901 | current_pgpath = choose_pgpath(m, 0); | |
9af4aa30 | 1902 | |
2da1610a | 1903 | if (current_pgpath) { |
518257b1 | 1904 | if (!test_bit(MPATHF_QUEUE_IO, &m->flags)) { |
2da1610a MS |
1905 | *bdev = current_pgpath->path.dev->bdev; |
1906 | *mode = current_pgpath->path.dev->mode; | |
43e43c9e JN |
1907 | r = 0; |
1908 | } else { | |
1909 | /* pg_init has not started or completed */ | |
1910 | r = -ENOTCONN; | |
1911 | } | |
1912 | } else { | |
1913 | /* No path is available */ | |
518257b1 | 1914 | if (test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) |
43e43c9e JN |
1915 | r = -ENOTCONN; |
1916 | else | |
1917 | r = -EIO; | |
e90dae1f | 1918 | } |
9af4aa30 | 1919 | |
5bbbfdf6 | 1920 | if (r == -ENOTCONN) { |
2da1610a | 1921 | if (!lockless_dereference(m->current_pg)) { |
3e9f1be1 | 1922 | /* Path status changed, redo selection */ |
2da1610a | 1923 | (void) choose_pgpath(m, 0); |
3e9f1be1 | 1924 | } |
518257b1 | 1925 | if (test_bit(MPATHF_PG_INIT_REQUIRED, &m->flags)) |
2da1610a | 1926 | pg_init_all_paths(m); |
63d832c3 | 1927 | dm_table_run_md_queue_async(m->ti->table); |
76e33fe4 | 1928 | process_queued_bios_list(m); |
3e9f1be1 | 1929 | } |
35991652 | 1930 | |
e56f81e0 CH |
1931 | /* |
1932 | * Only pass ioctls through if the device sizes match exactly. | |
1933 | */ | |
1934 | if (!r && ti->len != i_size_read((*bdev)->bd_inode) >> SECTOR_SHIFT) | |
1935 | return 1; | |
1936 | return r; | |
9af4aa30 MB |
1937 | } |
1938 | ||
af4874e0 MS |
1939 | static int multipath_iterate_devices(struct dm_target *ti, |
1940 | iterate_devices_callout_fn fn, void *data) | |
1941 | { | |
1942 | struct multipath *m = ti->private; | |
1943 | struct priority_group *pg; | |
1944 | struct pgpath *p; | |
1945 | int ret = 0; | |
1946 | ||
1947 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1948 | list_for_each_entry(p, &pg->pgpaths, list) { | |
5dea271b | 1949 | ret = fn(ti, p->path.dev, ti->begin, ti->len, data); |
af4874e0 MS |
1950 | if (ret) |
1951 | goto out; | |
1952 | } | |
1953 | } | |
1954 | ||
1955 | out: | |
1956 | return ret; | |
1957 | } | |
1958 | ||
9f54cec5 | 1959 | static int pgpath_busy(struct pgpath *pgpath) |
f40c67f0 KU |
1960 | { |
1961 | struct request_queue *q = bdev_get_queue(pgpath->path.dev->bdev); | |
1962 | ||
52b09914 | 1963 | return blk_lld_busy(q); |
f40c67f0 KU |
1964 | } |
1965 | ||
1966 | /* | |
1967 | * We return "busy", only when we can map I/Os but underlying devices | |
1968 | * are busy (so even if we map I/Os now, the I/Os will wait on | |
1969 | * the underlying queue). | |
1970 | * In other words, if we want to kill I/Os or queue them inside us | |
1971 | * due to map unavailability, we don't return "busy". Otherwise, | |
1972 | * dm core won't give us the I/Os and we can't do what we want. | |
1973 | */ | |
1974 | static int multipath_busy(struct dm_target *ti) | |
1975 | { | |
be7d31cc | 1976 | bool busy = false, has_active = false; |
f40c67f0 | 1977 | struct multipath *m = ti->private; |
2da1610a | 1978 | struct priority_group *pg, *next_pg; |
f40c67f0 | 1979 | struct pgpath *pgpath; |
f40c67f0 | 1980 | |
7a7a3b45 | 1981 | /* pg_init in progress or no paths available */ |
91e968aa | 1982 | if (atomic_read(&m->pg_init_in_progress) || |
2da1610a MS |
1983 | (!atomic_read(&m->nr_valid_paths) && test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags))) |
1984 | return true; | |
1985 | ||
f40c67f0 | 1986 | /* Guess which priority_group will be used at next mapping time */ |
2da1610a MS |
1987 | pg = lockless_dereference(m->current_pg); |
1988 | next_pg = lockless_dereference(m->next_pg); | |
1989 | if (unlikely(!lockless_dereference(m->current_pgpath) && next_pg)) | |
1990 | pg = next_pg; | |
1991 | ||
1992 | if (!pg) { | |
f40c67f0 KU |
1993 | /* |
1994 | * We don't know which pg will be used at next mapping time. | |
2da1610a | 1995 | * We don't call choose_pgpath() here to avoid to trigger |
f40c67f0 KU |
1996 | * pg_init just by busy checking. |
1997 | * So we don't know whether underlying devices we will be using | |
1998 | * at next mapping time are busy or not. Just try mapping. | |
1999 | */ | |
2da1610a MS |
2000 | return busy; |
2001 | } | |
f40c67f0 KU |
2002 | |
2003 | /* | |
2004 | * If there is one non-busy active path at least, the path selector | |
2005 | * will be able to select it. So we consider such a pg as not busy. | |
2006 | */ | |
be7d31cc | 2007 | busy = true; |
2da1610a | 2008 | list_for_each_entry(pgpath, &pg->pgpaths, list) { |
f40c67f0 | 2009 | if (pgpath->is_active) { |
be7d31cc | 2010 | has_active = true; |
9f54cec5 | 2011 | if (!pgpath_busy(pgpath)) { |
be7d31cc | 2012 | busy = false; |
f40c67f0 KU |
2013 | break; |
2014 | } | |
2015 | } | |
2da1610a | 2016 | } |
f40c67f0 | 2017 | |
2da1610a | 2018 | if (!has_active) { |
f40c67f0 KU |
2019 | /* |
2020 | * No active path in this pg, so this pg won't be used and | |
2021 | * the current_pg will be changed at next mapping time. | |
2022 | * We need to try mapping to determine it. | |
2023 | */ | |
be7d31cc | 2024 | busy = false; |
2da1610a | 2025 | } |
f40c67f0 KU |
2026 | |
2027 | return busy; | |
2028 | } | |
2029 | ||
1da177e4 LT |
2030 | /*----------------------------------------------------------------- |
2031 | * Module setup | |
2032 | *---------------------------------------------------------------*/ | |
2033 | static struct target_type multipath_target = { | |
2034 | .name = "multipath", | |
e83068a5 | 2035 | .version = {1, 12, 0}, |
16f12266 | 2036 | .features = DM_TARGET_SINGLETON | DM_TARGET_IMMUTABLE, |
1da177e4 LT |
2037 | .module = THIS_MODULE, |
2038 | .ctr = multipath_ctr, | |
2039 | .dtr = multipath_dtr, | |
f40c67f0 | 2040 | .map_rq = multipath_map, |
e5863d9a MS |
2041 | .clone_and_map_rq = multipath_clone_and_map, |
2042 | .release_clone_rq = multipath_release_clone, | |
f40c67f0 | 2043 | .rq_end_io = multipath_end_io, |
76e33fe4 MS |
2044 | .map = multipath_map_bio, |
2045 | .end_io = multipath_end_io_bio, | |
2046 | .presuspend = multipath_presuspend, | |
2047 | .postsuspend = multipath_postsuspend, | |
2048 | .resume = multipath_resume, | |
2049 | .status = multipath_status, | |
2050 | .message = multipath_message, | |
2051 | .prepare_ioctl = multipath_prepare_ioctl, | |
2052 | .iterate_devices = multipath_iterate_devices, | |
2053 | .busy = multipath_busy, | |
2054 | }; | |
2055 | ||
1da177e4 LT |
2056 | static int __init dm_multipath_init(void) |
2057 | { | |
2058 | int r; | |
2059 | ||
76e33fe4 | 2060 | /* allocate a slab for the dm_mpath_ios */ |
028867ac | 2061 | _mpio_cache = KMEM_CACHE(dm_mpath_io, 0); |
1da177e4 LT |
2062 | if (!_mpio_cache) |
2063 | return -ENOMEM; | |
2064 | ||
2065 | r = dm_register_target(&multipath_target); | |
2066 | if (r < 0) { | |
76e33fe4 | 2067 | DMERR("request-based register failed %d", r); |
ff658e9c JT |
2068 | r = -EINVAL; |
2069 | goto bad_register_target; | |
1da177e4 LT |
2070 | } |
2071 | ||
4d4d66ab | 2072 | kmultipathd = alloc_workqueue("kmpathd", WQ_MEM_RECLAIM, 0); |
c557308e | 2073 | if (!kmultipathd) { |
0cd33124 | 2074 | DMERR("failed to create workqueue kmpathd"); |
ff658e9c JT |
2075 | r = -ENOMEM; |
2076 | goto bad_alloc_kmultipathd; | |
c557308e AK |
2077 | } |
2078 | ||
bab7cfc7 CS |
2079 | /* |
2080 | * A separate workqueue is used to handle the device handlers | |
2081 | * to avoid overloading existing workqueue. Overloading the | |
2082 | * old workqueue would also create a bottleneck in the | |
2083 | * path of the storage hardware device activation. | |
2084 | */ | |
4d4d66ab TH |
2085 | kmpath_handlerd = alloc_ordered_workqueue("kmpath_handlerd", |
2086 | WQ_MEM_RECLAIM); | |
bab7cfc7 CS |
2087 | if (!kmpath_handlerd) { |
2088 | DMERR("failed to create workqueue kmpath_handlerd"); | |
ff658e9c JT |
2089 | r = -ENOMEM; |
2090 | goto bad_alloc_kmpath_handlerd; | |
bab7cfc7 CS |
2091 | } |
2092 | ||
ff658e9c JT |
2093 | return 0; |
2094 | ||
2095 | bad_alloc_kmpath_handlerd: | |
2096 | destroy_workqueue(kmultipathd); | |
2097 | bad_alloc_kmultipathd: | |
2098 | dm_unregister_target(&multipath_target); | |
2099 | bad_register_target: | |
2100 | kmem_cache_destroy(_mpio_cache); | |
2101 | ||
1da177e4 LT |
2102 | return r; |
2103 | } | |
2104 | ||
2105 | static void __exit dm_multipath_exit(void) | |
2106 | { | |
bab7cfc7 | 2107 | destroy_workqueue(kmpath_handlerd); |
c557308e AK |
2108 | destroy_workqueue(kmultipathd); |
2109 | ||
10d3bd09 | 2110 | dm_unregister_target(&multipath_target); |
1da177e4 LT |
2111 | kmem_cache_destroy(_mpio_cache); |
2112 | } | |
2113 | ||
1da177e4 LT |
2114 | module_init(dm_multipath_init); |
2115 | module_exit(dm_multipath_exit); | |
2116 | ||
2117 | MODULE_DESCRIPTION(DM_NAME " multipath target"); | |
2118 | MODULE_AUTHOR("Sistina Software <dm-devel@redhat.com>"); | |
2119 | MODULE_LICENSE("GPL"); |