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 | ||
4813577f | 375 | static void pg_init_all_paths(struct multipath *m) |
1da177e4 | 376 | { |
2da1610a MS |
377 | unsigned long flags; |
378 | ||
379 | spin_lock_irqsave(&m->lock, flags); | |
4813577f | 380 | __pg_init_all_paths(m); |
2da1610a | 381 | spin_unlock_irqrestore(&m->lock, flags); |
2da1610a MS |
382 | } |
383 | ||
384 | static void __switch_pg(struct multipath *m, struct priority_group *pg) | |
385 | { | |
386 | m->current_pg = pg; | |
1da177e4 LT |
387 | |
388 | /* Must we initialise the PG first, and queue I/O till it's ready? */ | |
cfae5c9b | 389 | if (m->hw_handler_name) { |
518257b1 MS |
390 | set_bit(MPATHF_PG_INIT_REQUIRED, &m->flags); |
391 | set_bit(MPATHF_QUEUE_IO, &m->flags); | |
1da177e4 | 392 | } else { |
518257b1 MS |
393 | clear_bit(MPATHF_PG_INIT_REQUIRED, &m->flags); |
394 | clear_bit(MPATHF_QUEUE_IO, &m->flags); | |
1da177e4 | 395 | } |
c9e45581 | 396 | |
91e968aa | 397 | atomic_set(&m->pg_init_count, 0); |
1da177e4 LT |
398 | } |
399 | ||
2da1610a MS |
400 | static struct pgpath *choose_path_in_pg(struct multipath *m, |
401 | struct priority_group *pg, | |
402 | size_t nr_bytes) | |
1da177e4 | 403 | { |
2da1610a | 404 | unsigned long flags; |
c922d5f7 | 405 | struct dm_path *path; |
2da1610a | 406 | struct pgpath *pgpath; |
1da177e4 | 407 | |
90a4323c | 408 | path = pg->ps.type->select_path(&pg->ps, nr_bytes); |
1da177e4 | 409 | if (!path) |
2da1610a | 410 | return ERR_PTR(-ENXIO); |
1da177e4 | 411 | |
2da1610a | 412 | pgpath = path_to_pgpath(path); |
1da177e4 | 413 | |
2da1610a MS |
414 | if (unlikely(lockless_dereference(m->current_pg) != pg)) { |
415 | /* Only update current_pgpath if pg changed */ | |
416 | spin_lock_irqsave(&m->lock, flags); | |
417 | m->current_pgpath = pgpath; | |
418 | __switch_pg(m, pg); | |
419 | spin_unlock_irqrestore(&m->lock, flags); | |
420 | } | |
1da177e4 | 421 | |
2da1610a | 422 | return pgpath; |
1da177e4 LT |
423 | } |
424 | ||
2da1610a | 425 | static struct pgpath *choose_pgpath(struct multipath *m, size_t nr_bytes) |
1da177e4 | 426 | { |
2da1610a | 427 | unsigned long flags; |
1da177e4 | 428 | struct priority_group *pg; |
2da1610a | 429 | struct pgpath *pgpath; |
be7d31cc | 430 | bool bypassed = true; |
1da177e4 | 431 | |
91e968aa | 432 | if (!atomic_read(&m->nr_valid_paths)) { |
518257b1 | 433 | clear_bit(MPATHF_QUEUE_IO, &m->flags); |
1da177e4 | 434 | goto failed; |
1f271972 | 435 | } |
1da177e4 LT |
436 | |
437 | /* Were we instructed to switch PG? */ | |
2da1610a MS |
438 | if (lockless_dereference(m->next_pg)) { |
439 | spin_lock_irqsave(&m->lock, flags); | |
1da177e4 | 440 | pg = m->next_pg; |
2da1610a MS |
441 | if (!pg) { |
442 | spin_unlock_irqrestore(&m->lock, flags); | |
443 | goto check_current_pg; | |
444 | } | |
1da177e4 | 445 | m->next_pg = NULL; |
2da1610a MS |
446 | spin_unlock_irqrestore(&m->lock, flags); |
447 | pgpath = choose_path_in_pg(m, pg, nr_bytes); | |
448 | if (!IS_ERR_OR_NULL(pgpath)) | |
449 | return pgpath; | |
1da177e4 LT |
450 | } |
451 | ||
452 | /* Don't change PG until it has no remaining paths */ | |
2da1610a MS |
453 | check_current_pg: |
454 | pg = lockless_dereference(m->current_pg); | |
455 | if (pg) { | |
456 | pgpath = choose_path_in_pg(m, pg, nr_bytes); | |
457 | if (!IS_ERR_OR_NULL(pgpath)) | |
458 | return pgpath; | |
459 | } | |
1da177e4 LT |
460 | |
461 | /* | |
462 | * Loop through priority groups until we find a valid path. | |
463 | * First time we skip PGs marked 'bypassed'. | |
f220fd4e MC |
464 | * Second time we only try the ones we skipped, but set |
465 | * pg_init_delay_retry so we do not hammer controllers. | |
1da177e4 LT |
466 | */ |
467 | do { | |
468 | list_for_each_entry(pg, &m->priority_groups, list) { | |
469 | if (pg->bypassed == bypassed) | |
470 | continue; | |
2da1610a MS |
471 | pgpath = choose_path_in_pg(m, pg, nr_bytes); |
472 | if (!IS_ERR_OR_NULL(pgpath)) { | |
f220fd4e | 473 | if (!bypassed) |
518257b1 | 474 | set_bit(MPATHF_PG_INIT_DELAY_RETRY, &m->flags); |
2da1610a | 475 | return pgpath; |
f220fd4e | 476 | } |
1da177e4 LT |
477 | } |
478 | } while (bypassed--); | |
479 | ||
480 | failed: | |
2da1610a | 481 | spin_lock_irqsave(&m->lock, flags); |
1da177e4 LT |
482 | m->current_pgpath = NULL; |
483 | m->current_pg = NULL; | |
2da1610a MS |
484 | spin_unlock_irqrestore(&m->lock, flags); |
485 | ||
486 | return NULL; | |
1da177e4 LT |
487 | } |
488 | ||
45e15720 KU |
489 | /* |
490 | * Check whether bios must be queued in the device-mapper core rather | |
491 | * than here in the target. | |
492 | * | |
45e15720 KU |
493 | * If m->queue_if_no_path and m->saved_queue_if_no_path hold the |
494 | * same value then we are not between multipath_presuspend() | |
495 | * and multipath_resume() calls and we have no need to check | |
496 | * for the DMF_NOFLUSH_SUSPENDING flag. | |
497 | */ | |
76e33fe4 MS |
498 | static bool __must_push_back(struct multipath *m) |
499 | { | |
500 | return ((test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags) != | |
501 | test_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &m->flags)) && | |
502 | dm_noflush_suspending(m->ti)); | |
503 | } | |
504 | ||
505 | static bool must_push_back_rq(struct multipath *m) | |
45e15720 | 506 | { |
1814f2e3 MS |
507 | bool r; |
508 | unsigned long flags; | |
509 | ||
510 | spin_lock_irqsave(&m->lock, flags); | |
511 | r = (test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags) || | |
512 | __must_push_back(m)); | |
513 | spin_unlock_irqrestore(&m->lock, flags); | |
514 | ||
515 | return r; | |
76e33fe4 MS |
516 | } |
517 | ||
518 | static bool must_push_back_bio(struct multipath *m) | |
519 | { | |
1814f2e3 MS |
520 | bool r; |
521 | unsigned long flags; | |
522 | ||
523 | spin_lock_irqsave(&m->lock, flags); | |
524 | r = __must_push_back(m); | |
525 | spin_unlock_irqrestore(&m->lock, flags); | |
526 | ||
527 | return r; | |
45e15720 KU |
528 | } |
529 | ||
36fcffcc | 530 | /* |
76e33fe4 | 531 | * Map cloned requests (request-based multipath) |
36fcffcc | 532 | */ |
e5863d9a MS |
533 | static int __multipath_map(struct dm_target *ti, struct request *clone, |
534 | union map_info *map_context, | |
535 | struct request *rq, struct request **__clone) | |
1da177e4 | 536 | { |
7943bd6d | 537 | struct multipath *m = ti->private; |
e3bde04f | 538 | int r = DM_MAPIO_REQUEUE; |
e5863d9a | 539 | size_t nr_bytes = clone ? blk_rq_bytes(clone) : blk_rq_bytes(rq); |
1da177e4 | 540 | struct pgpath *pgpath; |
f40c67f0 | 541 | struct block_device *bdev; |
e3bde04f | 542 | struct dm_mpath_io *mpio; |
1da177e4 | 543 | |
1da177e4 | 544 | /* Do we need to select a new pgpath? */ |
2da1610a MS |
545 | pgpath = lockless_dereference(m->current_pgpath); |
546 | if (!pgpath || !test_bit(MPATHF_QUEUE_IO, &m->flags)) | |
547 | pgpath = choose_pgpath(m, nr_bytes); | |
1da177e4 | 548 | |
9bf59a61 | 549 | if (!pgpath) { |
b88efd43 MS |
550 | if (must_push_back_rq(m)) |
551 | return DM_MAPIO_DELAY_REQUEUE; | |
552 | return -EIO; /* Failed */ | |
518257b1 MS |
553 | } else if (test_bit(MPATHF_QUEUE_IO, &m->flags) || |
554 | test_bit(MPATHF_PG_INIT_REQUIRED, &m->flags)) { | |
2da1610a MS |
555 | pg_init_all_paths(m); |
556 | return r; | |
9bf59a61 | 557 | } |
6afbc01d | 558 | |
2eff1924 MS |
559 | mpio = set_mpio(m, map_context); |
560 | if (!mpio) | |
9bf59a61 | 561 | /* ENOMEM, requeue */ |
2da1610a | 562 | return r; |
9bf59a61 | 563 | |
2eb6e1e3 KB |
564 | mpio->pgpath = pgpath; |
565 | mpio->nr_bytes = nr_bytes; | |
566 | ||
9bf59a61 | 567 | bdev = pgpath->path.dev->bdev; |
2eb6e1e3 | 568 | |
e5863d9a | 569 | if (clone) { |
c5248f79 MS |
570 | /* |
571 | * Old request-based interface: allocated clone is passed in. | |
572 | * Used by: .request_fn stacked on .request_fn path(s). | |
573 | */ | |
e5863d9a MS |
574 | clone->q = bdev_get_queue(bdev); |
575 | clone->rq_disk = bdev->bd_disk; | |
576 | clone->cmd_flags |= REQ_FAILFAST_TRANSPORT; | |
577 | } else { | |
eca7ee6d MS |
578 | /* |
579 | * blk-mq request-based interface; used by both: | |
580 | * .request_fn stacked on blk-mq path(s) and | |
581 | * blk-mq stacked on blk-mq path(s). | |
582 | */ | |
6599c84e BVA |
583 | clone = blk_mq_alloc_request(bdev_get_queue(bdev), |
584 | rq_data_dir(rq), BLK_MQ_REQ_NOWAIT); | |
585 | if (IS_ERR(clone)) { | |
586 | /* EBUSY, ENODEV or EWOULDBLOCK: requeue */ | |
2eff1924 | 587 | clear_request_fn_mpio(m, map_context); |
e5863d9a | 588 | return r; |
4c6dd53d | 589 | } |
6599c84e BVA |
590 | clone->bio = clone->biotail = NULL; |
591 | clone->rq_disk = bdev->bd_disk; | |
592 | clone->cmd_flags |= REQ_FAILFAST_TRANSPORT; | |
593 | *__clone = clone; | |
e5863d9a MS |
594 | } |
595 | ||
9bf59a61 MS |
596 | if (pgpath->pg->ps.type->start_io) |
597 | pgpath->pg->ps.type->start_io(&pgpath->pg->ps, | |
598 | &pgpath->path, | |
599 | nr_bytes); | |
2eb6e1e3 | 600 | return DM_MAPIO_REMAPPED; |
1da177e4 LT |
601 | } |
602 | ||
e5863d9a MS |
603 | static int multipath_map(struct dm_target *ti, struct request *clone, |
604 | union map_info *map_context) | |
605 | { | |
606 | return __multipath_map(ti, clone, map_context, NULL, NULL); | |
607 | } | |
608 | ||
609 | static int multipath_clone_and_map(struct dm_target *ti, struct request *rq, | |
610 | union map_info *map_context, | |
611 | struct request **clone) | |
612 | { | |
613 | return __multipath_map(ti, NULL, map_context, rq, clone); | |
614 | } | |
615 | ||
616 | static void multipath_release_clone(struct request *clone) | |
617 | { | |
78ce23b5 | 618 | blk_mq_free_request(clone); |
e5863d9a MS |
619 | } |
620 | ||
76e33fe4 MS |
621 | /* |
622 | * Map cloned bios (bio-based multipath) | |
623 | */ | |
624 | static int __multipath_map_bio(struct multipath *m, struct bio *bio, struct dm_mpath_io *mpio) | |
625 | { | |
626 | size_t nr_bytes = bio->bi_iter.bi_size; | |
627 | struct pgpath *pgpath; | |
628 | unsigned long flags; | |
629 | bool queue_io; | |
630 | ||
631 | /* Do we need to select a new pgpath? */ | |
632 | pgpath = lockless_dereference(m->current_pgpath); | |
633 | queue_io = test_bit(MPATHF_QUEUE_IO, &m->flags); | |
634 | if (!pgpath || !queue_io) | |
635 | pgpath = choose_pgpath(m, nr_bytes); | |
636 | ||
637 | if ((pgpath && queue_io) || | |
638 | (!pgpath && test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags))) { | |
639 | /* Queue for the daemon to resubmit */ | |
640 | spin_lock_irqsave(&m->lock, flags); | |
641 | bio_list_add(&m->queued_bios, bio); | |
642 | spin_unlock_irqrestore(&m->lock, flags); | |
643 | /* PG_INIT_REQUIRED cannot be set without QUEUE_IO */ | |
644 | if (queue_io || test_bit(MPATHF_PG_INIT_REQUIRED, &m->flags)) | |
645 | pg_init_all_paths(m); | |
646 | else if (!queue_io) | |
647 | queue_work(kmultipathd, &m->process_queued_bios); | |
648 | return DM_MAPIO_SUBMITTED; | |
649 | } | |
650 | ||
651 | if (!pgpath) { | |
652 | if (!must_push_back_bio(m)) | |
653 | return -EIO; | |
654 | return DM_MAPIO_REQUEUE; | |
655 | } | |
656 | ||
657 | mpio->pgpath = pgpath; | |
658 | mpio->nr_bytes = nr_bytes; | |
659 | ||
660 | bio->bi_error = 0; | |
661 | bio->bi_bdev = pgpath->path.dev->bdev; | |
1eff9d32 | 662 | bio->bi_opf |= REQ_FAILFAST_TRANSPORT; |
76e33fe4 MS |
663 | |
664 | if (pgpath->pg->ps.type->start_io) | |
665 | pgpath->pg->ps.type->start_io(&pgpath->pg->ps, | |
666 | &pgpath->path, | |
667 | nr_bytes); | |
668 | return DM_MAPIO_REMAPPED; | |
669 | } | |
670 | ||
671 | static int multipath_map_bio(struct dm_target *ti, struct bio *bio) | |
672 | { | |
673 | struct multipath *m = ti->private; | |
bf661be1 MS |
674 | struct dm_mpath_io *mpio = NULL; |
675 | ||
676 | multipath_init_per_bio_data(bio, &mpio, NULL); | |
76e33fe4 MS |
677 | |
678 | return __multipath_map_bio(m, bio, mpio); | |
679 | } | |
680 | ||
7e48c768 | 681 | static void process_queued_io_list(struct multipath *m) |
76e33fe4 | 682 | { |
7e48c768 MS |
683 | if (m->queue_mode == DM_TYPE_MQ_REQUEST_BASED) |
684 | dm_mq_kick_requeue_list(dm_table_get_md(m->ti->table)); | |
685 | else if (m->queue_mode == DM_TYPE_BIO_BASED) | |
76e33fe4 MS |
686 | queue_work(kmultipathd, &m->process_queued_bios); |
687 | } | |
688 | ||
689 | static void process_queued_bios(struct work_struct *work) | |
690 | { | |
691 | int r; | |
692 | unsigned long flags; | |
693 | struct bio *bio; | |
694 | struct bio_list bios; | |
695 | struct blk_plug plug; | |
696 | struct multipath *m = | |
697 | container_of(work, struct multipath, process_queued_bios); | |
698 | ||
699 | bio_list_init(&bios); | |
700 | ||
701 | spin_lock_irqsave(&m->lock, flags); | |
702 | ||
703 | if (bio_list_empty(&m->queued_bios)) { | |
704 | spin_unlock_irqrestore(&m->lock, flags); | |
705 | return; | |
706 | } | |
707 | ||
708 | bio_list_merge(&bios, &m->queued_bios); | |
709 | bio_list_init(&m->queued_bios); | |
710 | ||
711 | spin_unlock_irqrestore(&m->lock, flags); | |
712 | ||
713 | blk_start_plug(&plug); | |
714 | while ((bio = bio_list_pop(&bios))) { | |
715 | r = __multipath_map_bio(m, bio, get_mpio_from_bio(bio)); | |
716 | if (r < 0 || r == DM_MAPIO_REQUEUE) { | |
717 | bio->bi_error = r; | |
718 | bio_endio(bio); | |
719 | } else if (r == DM_MAPIO_REMAPPED) | |
720 | generic_make_request(bio); | |
721 | } | |
722 | blk_finish_plug(&plug); | |
723 | } | |
724 | ||
1da177e4 LT |
725 | /* |
726 | * If we run out of usable paths, should we queue I/O or error it? | |
727 | */ | |
be7d31cc MS |
728 | static int queue_if_no_path(struct multipath *m, bool queue_if_no_path, |
729 | bool save_old_value) | |
1da177e4 LT |
730 | { |
731 | unsigned long flags; | |
732 | ||
733 | spin_lock_irqsave(&m->lock, flags); | |
734 | ||
518257b1 MS |
735 | if (save_old_value) { |
736 | if (test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) | |
737 | set_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &m->flags); | |
738 | else | |
739 | clear_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &m->flags); | |
740 | } else { | |
741 | if (queue_if_no_path) | |
742 | set_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &m->flags); | |
743 | else | |
744 | clear_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &m->flags); | |
745 | } | |
746 | if (queue_if_no_path) | |
747 | set_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags); | |
485ef69e | 748 | else |
518257b1 MS |
749 | clear_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags); |
750 | ||
1da177e4 LT |
751 | spin_unlock_irqrestore(&m->lock, flags); |
752 | ||
76e33fe4 | 753 | if (!queue_if_no_path) { |
63d832c3 | 754 | dm_table_run_md_queue_async(m->ti->table); |
7e48c768 | 755 | process_queued_io_list(m); |
76e33fe4 | 756 | } |
63d832c3 | 757 | |
1da177e4 LT |
758 | return 0; |
759 | } | |
760 | ||
1da177e4 LT |
761 | /* |
762 | * An event is triggered whenever a path is taken out of use. | |
763 | * Includes path failure and PG bypass. | |
764 | */ | |
c4028958 | 765 | static void trigger_event(struct work_struct *work) |
1da177e4 | 766 | { |
c4028958 DH |
767 | struct multipath *m = |
768 | container_of(work, struct multipath, trigger_event); | |
1da177e4 LT |
769 | |
770 | dm_table_event(m->ti->table); | |
771 | } | |
772 | ||
773 | /*----------------------------------------------------------------- | |
774 | * Constructor/argument parsing: | |
775 | * <#multipath feature args> [<arg>]* | |
776 | * <#hw_handler args> [hw_handler [<arg>]*] | |
777 | * <#priority groups> | |
778 | * <initial priority group> | |
779 | * [<selector> <#selector args> [<arg>]* | |
780 | * <#paths> <#per-path selector args> | |
781 | * [<path> [<arg>]* ]+ ]+ | |
782 | *---------------------------------------------------------------*/ | |
498f0103 | 783 | static int parse_path_selector(struct dm_arg_set *as, struct priority_group *pg, |
1da177e4 LT |
784 | struct dm_target *ti) |
785 | { | |
786 | int r; | |
787 | struct path_selector_type *pst; | |
788 | unsigned ps_argc; | |
789 | ||
498f0103 | 790 | static struct dm_arg _args[] = { |
72d94861 | 791 | {0, 1024, "invalid number of path selector args"}, |
1da177e4 LT |
792 | }; |
793 | ||
498f0103 | 794 | pst = dm_get_path_selector(dm_shift_arg(as)); |
1da177e4 | 795 | if (!pst) { |
72d94861 | 796 | ti->error = "unknown path selector type"; |
1da177e4 LT |
797 | return -EINVAL; |
798 | } | |
799 | ||
498f0103 | 800 | r = dm_read_arg_group(_args, as, &ps_argc, &ti->error); |
371b2e34 MP |
801 | if (r) { |
802 | dm_put_path_selector(pst); | |
1da177e4 | 803 | return -EINVAL; |
371b2e34 | 804 | } |
1da177e4 LT |
805 | |
806 | r = pst->create(&pg->ps, ps_argc, as->argv); | |
807 | if (r) { | |
808 | dm_put_path_selector(pst); | |
72d94861 | 809 | ti->error = "path selector constructor failed"; |
1da177e4 LT |
810 | return r; |
811 | } | |
812 | ||
813 | pg->ps.type = pst; | |
498f0103 | 814 | dm_consume_args(as, ps_argc); |
1da177e4 LT |
815 | |
816 | return 0; | |
817 | } | |
818 | ||
498f0103 | 819 | static struct pgpath *parse_path(struct dm_arg_set *as, struct path_selector *ps, |
1da177e4 LT |
820 | struct dm_target *ti) |
821 | { | |
822 | int r; | |
823 | struct pgpath *p; | |
ae11b1b3 | 824 | struct multipath *m = ti->private; |
a58a935d MS |
825 | struct request_queue *q = NULL; |
826 | const char *attached_handler_name; | |
1da177e4 LT |
827 | |
828 | /* we need at least a path arg */ | |
829 | if (as->argc < 1) { | |
72d94861 | 830 | ti->error = "no device given"; |
01460f35 | 831 | return ERR_PTR(-EINVAL); |
1da177e4 LT |
832 | } |
833 | ||
834 | p = alloc_pgpath(); | |
835 | if (!p) | |
01460f35 | 836 | return ERR_PTR(-ENOMEM); |
1da177e4 | 837 | |
498f0103 | 838 | r = dm_get_device(ti, dm_shift_arg(as), dm_table_get_mode(ti->table), |
8215d6ec | 839 | &p->path.dev); |
1da177e4 | 840 | if (r) { |
72d94861 | 841 | ti->error = "error getting device"; |
1da177e4 LT |
842 | goto bad; |
843 | } | |
844 | ||
518257b1 | 845 | if (test_bit(MPATHF_RETAIN_ATTACHED_HW_HANDLER, &m->flags) || m->hw_handler_name) |
a58a935d MS |
846 | q = bdev_get_queue(p->path.dev->bdev); |
847 | ||
518257b1 | 848 | if (test_bit(MPATHF_RETAIN_ATTACHED_HW_HANDLER, &m->flags)) { |
1bab0de0 | 849 | retain: |
a58a935d MS |
850 | attached_handler_name = scsi_dh_attached_handler_name(q, GFP_KERNEL); |
851 | if (attached_handler_name) { | |
852 | /* | |
853 | * Reset hw_handler_name to match the attached handler | |
854 | * and clear any hw_handler_params associated with the | |
855 | * ignored handler. | |
856 | * | |
857 | * NB. This modifies the table line to show the actual | |
858 | * handler instead of the original table passed in. | |
859 | */ | |
860 | kfree(m->hw_handler_name); | |
861 | m->hw_handler_name = attached_handler_name; | |
862 | ||
863 | kfree(m->hw_handler_params); | |
864 | m->hw_handler_params = NULL; | |
865 | } | |
866 | } | |
a0cf7ea9 | 867 | |
a58a935d | 868 | if (m->hw_handler_name) { |
a0cf7ea9 HR |
869 | r = scsi_dh_attach(q, m->hw_handler_name); |
870 | if (r == -EBUSY) { | |
1bab0de0 | 871 | char b[BDEVNAME_SIZE]; |
a0cf7ea9 | 872 | |
1bab0de0 CH |
873 | printk(KERN_INFO "dm-mpath: retaining handler on device %s\n", |
874 | bdevname(p->path.dev->bdev, b)); | |
875 | goto retain; | |
876 | } | |
ae11b1b3 | 877 | if (r < 0) { |
a0cf7ea9 | 878 | ti->error = "error attaching hardware handler"; |
ae11b1b3 HR |
879 | dm_put_device(ti, p->path.dev); |
880 | goto bad; | |
881 | } | |
2bfd2e13 CS |
882 | |
883 | if (m->hw_handler_params) { | |
884 | r = scsi_dh_set_params(q, m->hw_handler_params); | |
885 | if (r < 0) { | |
886 | ti->error = "unable to set hardware " | |
887 | "handler parameters"; | |
2bfd2e13 CS |
888 | dm_put_device(ti, p->path.dev); |
889 | goto bad; | |
890 | } | |
891 | } | |
ae11b1b3 HR |
892 | } |
893 | ||
1da177e4 LT |
894 | r = ps->type->add_path(ps, &p->path, as->argc, as->argv, &ti->error); |
895 | if (r) { | |
896 | dm_put_device(ti, p->path.dev); | |
897 | goto bad; | |
898 | } | |
899 | ||
900 | return p; | |
901 | ||
902 | bad: | |
903 | free_pgpath(p); | |
01460f35 | 904 | return ERR_PTR(r); |
1da177e4 LT |
905 | } |
906 | ||
498f0103 | 907 | static struct priority_group *parse_priority_group(struct dm_arg_set *as, |
28f16c20 | 908 | struct multipath *m) |
1da177e4 | 909 | { |
498f0103 | 910 | static struct dm_arg _args[] = { |
72d94861 AK |
911 | {1, 1024, "invalid number of paths"}, |
912 | {0, 1024, "invalid number of selector args"} | |
1da177e4 LT |
913 | }; |
914 | ||
915 | int r; | |
498f0103 | 916 | unsigned i, nr_selector_args, nr_args; |
1da177e4 | 917 | struct priority_group *pg; |
28f16c20 | 918 | struct dm_target *ti = m->ti; |
1da177e4 LT |
919 | |
920 | if (as->argc < 2) { | |
921 | as->argc = 0; | |
01460f35 BM |
922 | ti->error = "not enough priority group arguments"; |
923 | return ERR_PTR(-EINVAL); | |
1da177e4 LT |
924 | } |
925 | ||
926 | pg = alloc_priority_group(); | |
927 | if (!pg) { | |
72d94861 | 928 | ti->error = "couldn't allocate priority group"; |
01460f35 | 929 | return ERR_PTR(-ENOMEM); |
1da177e4 LT |
930 | } |
931 | pg->m = m; | |
932 | ||
933 | r = parse_path_selector(as, pg, ti); | |
934 | if (r) | |
935 | goto bad; | |
936 | ||
937 | /* | |
938 | * read the paths | |
939 | */ | |
498f0103 | 940 | r = dm_read_arg(_args, as, &pg->nr_pgpaths, &ti->error); |
1da177e4 LT |
941 | if (r) |
942 | goto bad; | |
943 | ||
498f0103 | 944 | r = dm_read_arg(_args + 1, as, &nr_selector_args, &ti->error); |
1da177e4 LT |
945 | if (r) |
946 | goto bad; | |
947 | ||
498f0103 | 948 | nr_args = 1 + nr_selector_args; |
1da177e4 LT |
949 | for (i = 0; i < pg->nr_pgpaths; i++) { |
950 | struct pgpath *pgpath; | |
498f0103 | 951 | struct dm_arg_set path_args; |
1da177e4 | 952 | |
498f0103 | 953 | if (as->argc < nr_args) { |
148acff6 | 954 | ti->error = "not enough path parameters"; |
6bbf79a1 | 955 | r = -EINVAL; |
1da177e4 | 956 | goto bad; |
148acff6 | 957 | } |
1da177e4 | 958 | |
498f0103 | 959 | path_args.argc = nr_args; |
1da177e4 LT |
960 | path_args.argv = as->argv; |
961 | ||
962 | pgpath = parse_path(&path_args, &pg->ps, ti); | |
01460f35 BM |
963 | if (IS_ERR(pgpath)) { |
964 | r = PTR_ERR(pgpath); | |
1da177e4 | 965 | goto bad; |
01460f35 | 966 | } |
1da177e4 LT |
967 | |
968 | pgpath->pg = pg; | |
969 | list_add_tail(&pgpath->list, &pg->pgpaths); | |
498f0103 | 970 | dm_consume_args(as, nr_args); |
1da177e4 LT |
971 | } |
972 | ||
973 | return pg; | |
974 | ||
975 | bad: | |
976 | free_priority_group(pg, ti); | |
01460f35 | 977 | return ERR_PTR(r); |
1da177e4 LT |
978 | } |
979 | ||
498f0103 | 980 | static int parse_hw_handler(struct dm_arg_set *as, struct multipath *m) |
1da177e4 | 981 | { |
1da177e4 | 982 | unsigned hw_argc; |
2bfd2e13 | 983 | int ret; |
28f16c20 | 984 | struct dm_target *ti = m->ti; |
1da177e4 | 985 | |
498f0103 | 986 | static struct dm_arg _args[] = { |
72d94861 | 987 | {0, 1024, "invalid number of hardware handler args"}, |
1da177e4 LT |
988 | }; |
989 | ||
498f0103 | 990 | if (dm_read_arg_group(_args, as, &hw_argc, &ti->error)) |
1da177e4 LT |
991 | return -EINVAL; |
992 | ||
993 | if (!hw_argc) | |
994 | return 0; | |
995 | ||
e83068a5 | 996 | if (m->queue_mode == DM_TYPE_BIO_BASED) { |
76e33fe4 MS |
997 | dm_consume_args(as, hw_argc); |
998 | DMERR("bio-based multipath doesn't allow hardware handler args"); | |
999 | return 0; | |
1000 | } | |
1001 | ||
498f0103 | 1002 | m->hw_handler_name = kstrdup(dm_shift_arg(as), GFP_KERNEL); |
f97dc421 | 1003 | if (!m->hw_handler_name) |
1004 | return -EINVAL; | |
14e98c5c | 1005 | |
2bfd2e13 CS |
1006 | if (hw_argc > 1) { |
1007 | char *p; | |
1008 | int i, j, len = 4; | |
1009 | ||
1010 | for (i = 0; i <= hw_argc - 2; i++) | |
1011 | len += strlen(as->argv[i]) + 1; | |
1012 | p = m->hw_handler_params = kzalloc(len, GFP_KERNEL); | |
1013 | if (!p) { | |
1014 | ti->error = "memory allocation failed"; | |
1015 | ret = -ENOMEM; | |
1016 | goto fail; | |
1017 | } | |
1018 | j = sprintf(p, "%d", hw_argc - 1); | |
1019 | for (i = 0, p+=j+1; i <= hw_argc - 2; i++, p+=j+1) | |
1020 | j = sprintf(p, "%s", as->argv[i]); | |
1021 | } | |
498f0103 | 1022 | dm_consume_args(as, hw_argc - 1); |
1da177e4 LT |
1023 | |
1024 | return 0; | |
2bfd2e13 CS |
1025 | fail: |
1026 | kfree(m->hw_handler_name); | |
1027 | m->hw_handler_name = NULL; | |
1028 | return ret; | |
1da177e4 LT |
1029 | } |
1030 | ||
498f0103 | 1031 | static int parse_features(struct dm_arg_set *as, struct multipath *m) |
1da177e4 LT |
1032 | { |
1033 | int r; | |
1034 | unsigned argc; | |
28f16c20 | 1035 | struct dm_target *ti = m->ti; |
498f0103 | 1036 | const char *arg_name; |
1da177e4 | 1037 | |
498f0103 | 1038 | static struct dm_arg _args[] = { |
e83068a5 | 1039 | {0, 8, "invalid number of feature args"}, |
c9e45581 | 1040 | {1, 50, "pg_init_retries must be between 1 and 50"}, |
4e2d19e4 | 1041 | {0, 60000, "pg_init_delay_msecs must be between 0 and 60000"}, |
1da177e4 LT |
1042 | }; |
1043 | ||
498f0103 | 1044 | r = dm_read_arg_group(_args, as, &argc, &ti->error); |
1da177e4 LT |
1045 | if (r) |
1046 | return -EINVAL; | |
1047 | ||
1048 | if (!argc) | |
1049 | return 0; | |
1050 | ||
c9e45581 | 1051 | do { |
498f0103 | 1052 | arg_name = dm_shift_arg(as); |
c9e45581 DW |
1053 | argc--; |
1054 | ||
498f0103 | 1055 | if (!strcasecmp(arg_name, "queue_if_no_path")) { |
be7d31cc | 1056 | r = queue_if_no_path(m, true, false); |
c9e45581 DW |
1057 | continue; |
1058 | } | |
1059 | ||
a58a935d | 1060 | if (!strcasecmp(arg_name, "retain_attached_hw_handler")) { |
518257b1 | 1061 | set_bit(MPATHF_RETAIN_ATTACHED_HW_HANDLER, &m->flags); |
a58a935d MS |
1062 | continue; |
1063 | } | |
1064 | ||
498f0103 | 1065 | if (!strcasecmp(arg_name, "pg_init_retries") && |
c9e45581 | 1066 | (argc >= 1)) { |
498f0103 | 1067 | r = dm_read_arg(_args + 1, as, &m->pg_init_retries, &ti->error); |
c9e45581 DW |
1068 | argc--; |
1069 | continue; | |
1070 | } | |
1071 | ||
498f0103 | 1072 | if (!strcasecmp(arg_name, "pg_init_delay_msecs") && |
4e2d19e4 | 1073 | (argc >= 1)) { |
498f0103 | 1074 | r = dm_read_arg(_args + 2, as, &m->pg_init_delay_msecs, &ti->error); |
4e2d19e4 CS |
1075 | argc--; |
1076 | continue; | |
1077 | } | |
1078 | ||
e83068a5 MS |
1079 | if (!strcasecmp(arg_name, "queue_mode") && |
1080 | (argc >= 1)) { | |
1081 | const char *queue_mode_name = dm_shift_arg(as); | |
1082 | ||
1083 | if (!strcasecmp(queue_mode_name, "bio")) | |
1084 | m->queue_mode = DM_TYPE_BIO_BASED; | |
1085 | else if (!strcasecmp(queue_mode_name, "rq")) | |
1086 | m->queue_mode = DM_TYPE_REQUEST_BASED; | |
1087 | else if (!strcasecmp(queue_mode_name, "mq")) | |
1088 | m->queue_mode = DM_TYPE_MQ_REQUEST_BASED; | |
1089 | else { | |
1090 | ti->error = "Unknown 'queue_mode' requested"; | |
1091 | r = -EINVAL; | |
1092 | } | |
1093 | argc--; | |
1094 | continue; | |
1095 | } | |
1096 | ||
1da177e4 | 1097 | ti->error = "Unrecognised multipath feature request"; |
c9e45581 DW |
1098 | r = -EINVAL; |
1099 | } while (argc && !r); | |
1100 | ||
1101 | return r; | |
1da177e4 LT |
1102 | } |
1103 | ||
e83068a5 | 1104 | static int multipath_ctr(struct dm_target *ti, unsigned argc, char **argv) |
1da177e4 | 1105 | { |
498f0103 MS |
1106 | /* target arguments */ |
1107 | static struct dm_arg _args[] = { | |
a490a07a MS |
1108 | {0, 1024, "invalid number of priority groups"}, |
1109 | {0, 1024, "invalid initial priority group number"}, | |
1da177e4 LT |
1110 | }; |
1111 | ||
1112 | int r; | |
1113 | struct multipath *m; | |
498f0103 | 1114 | struct dm_arg_set as; |
1da177e4 LT |
1115 | unsigned pg_count = 0; |
1116 | unsigned next_pg_num; | |
1117 | ||
1118 | as.argc = argc; | |
1119 | as.argv = argv; | |
1120 | ||
e83068a5 | 1121 | m = alloc_multipath(ti); |
1da177e4 | 1122 | if (!m) { |
72d94861 | 1123 | ti->error = "can't allocate multipath"; |
1da177e4 LT |
1124 | return -EINVAL; |
1125 | } | |
1126 | ||
28f16c20 | 1127 | r = parse_features(&as, m); |
1da177e4 LT |
1128 | if (r) |
1129 | goto bad; | |
1130 | ||
e83068a5 MS |
1131 | r = alloc_multipath_stage2(ti, m); |
1132 | if (r) | |
1133 | goto bad; | |
1134 | ||
28f16c20 | 1135 | r = parse_hw_handler(&as, m); |
1da177e4 LT |
1136 | if (r) |
1137 | goto bad; | |
1138 | ||
498f0103 | 1139 | r = dm_read_arg(_args, &as, &m->nr_priority_groups, &ti->error); |
1da177e4 LT |
1140 | if (r) |
1141 | goto bad; | |
1142 | ||
498f0103 | 1143 | r = dm_read_arg(_args + 1, &as, &next_pg_num, &ti->error); |
1da177e4 LT |
1144 | if (r) |
1145 | goto bad; | |
1146 | ||
a490a07a MS |
1147 | if ((!m->nr_priority_groups && next_pg_num) || |
1148 | (m->nr_priority_groups && !next_pg_num)) { | |
1149 | ti->error = "invalid initial priority group"; | |
1150 | r = -EINVAL; | |
1151 | goto bad; | |
1152 | } | |
1153 | ||
1da177e4 LT |
1154 | /* parse the priority groups */ |
1155 | while (as.argc) { | |
1156 | struct priority_group *pg; | |
91e968aa | 1157 | unsigned nr_valid_paths = atomic_read(&m->nr_valid_paths); |
1da177e4 | 1158 | |
28f16c20 | 1159 | pg = parse_priority_group(&as, m); |
01460f35 BM |
1160 | if (IS_ERR(pg)) { |
1161 | r = PTR_ERR(pg); | |
1da177e4 LT |
1162 | goto bad; |
1163 | } | |
1164 | ||
91e968aa MS |
1165 | nr_valid_paths += pg->nr_pgpaths; |
1166 | atomic_set(&m->nr_valid_paths, nr_valid_paths); | |
1167 | ||
1da177e4 LT |
1168 | list_add_tail(&pg->list, &m->priority_groups); |
1169 | pg_count++; | |
1170 | pg->pg_num = pg_count; | |
1171 | if (!--next_pg_num) | |
1172 | m->next_pg = pg; | |
1173 | } | |
1174 | ||
1175 | if (pg_count != m->nr_priority_groups) { | |
72d94861 | 1176 | ti->error = "priority group count mismatch"; |
1da177e4 LT |
1177 | r = -EINVAL; |
1178 | goto bad; | |
1179 | } | |
1180 | ||
55a62eef AK |
1181 | ti->num_flush_bios = 1; |
1182 | ti->num_discard_bios = 1; | |
042bcef8 | 1183 | ti->num_write_same_bios = 1; |
e83068a5 | 1184 | if (m->queue_mode == DM_TYPE_BIO_BASED) |
bf661be1 | 1185 | ti->per_io_data_size = multipath_per_bio_data_size(); |
e83068a5 | 1186 | else if (m->queue_mode == DM_TYPE_MQ_REQUEST_BASED) |
8637a6bf | 1187 | ti->per_io_data_size = sizeof(struct dm_mpath_io); |
8627921f | 1188 | |
1da177e4 LT |
1189 | return 0; |
1190 | ||
1191 | bad: | |
1192 | free_multipath(m); | |
1193 | return r; | |
1194 | } | |
1195 | ||
2bded7bd KU |
1196 | static void multipath_wait_for_pg_init_completion(struct multipath *m) |
1197 | { | |
9f4c3f87 | 1198 | DEFINE_WAIT(wait); |
2bded7bd KU |
1199 | |
1200 | while (1) { | |
9f4c3f87 | 1201 | prepare_to_wait(&m->pg_init_wait, &wait, TASK_UNINTERRUPTIBLE); |
2bded7bd | 1202 | |
91e968aa | 1203 | if (!atomic_read(&m->pg_init_in_progress)) |
2bded7bd | 1204 | break; |
2bded7bd KU |
1205 | |
1206 | io_schedule(); | |
1207 | } | |
9f4c3f87 | 1208 | finish_wait(&m->pg_init_wait, &wait); |
2bded7bd KU |
1209 | } |
1210 | ||
1211 | static void flush_multipath_work(struct multipath *m) | |
1da177e4 | 1212 | { |
518257b1 MS |
1213 | set_bit(MPATHF_PG_INIT_DISABLED, &m->flags); |
1214 | smp_mb__after_atomic(); | |
954a73d5 | 1215 | |
bab7cfc7 | 1216 | flush_workqueue(kmpath_handlerd); |
2bded7bd | 1217 | multipath_wait_for_pg_init_completion(m); |
a044d016 | 1218 | flush_workqueue(kmultipathd); |
43829731 | 1219 | flush_work(&m->trigger_event); |
954a73d5 | 1220 | |
518257b1 MS |
1221 | clear_bit(MPATHF_PG_INIT_DISABLED, &m->flags); |
1222 | smp_mb__after_atomic(); | |
6df400ab KU |
1223 | } |
1224 | ||
1225 | static void multipath_dtr(struct dm_target *ti) | |
1226 | { | |
1227 | struct multipath *m = ti->private; | |
1228 | ||
2bded7bd | 1229 | flush_multipath_work(m); |
1da177e4 LT |
1230 | free_multipath(m); |
1231 | } | |
1232 | ||
1da177e4 LT |
1233 | /* |
1234 | * Take a path out of use. | |
1235 | */ | |
1236 | static int fail_path(struct pgpath *pgpath) | |
1237 | { | |
1238 | unsigned long flags; | |
1239 | struct multipath *m = pgpath->pg->m; | |
1240 | ||
1241 | spin_lock_irqsave(&m->lock, flags); | |
1242 | ||
6680073d | 1243 | if (!pgpath->is_active) |
1da177e4 LT |
1244 | goto out; |
1245 | ||
72d94861 | 1246 | DMWARN("Failing path %s.", pgpath->path.dev->name); |
1da177e4 LT |
1247 | |
1248 | pgpath->pg->ps.type->fail_path(&pgpath->pg->ps, &pgpath->path); | |
be7d31cc | 1249 | pgpath->is_active = false; |
1da177e4 LT |
1250 | pgpath->fail_count++; |
1251 | ||
91e968aa | 1252 | atomic_dec(&m->nr_valid_paths); |
1da177e4 LT |
1253 | |
1254 | if (pgpath == m->current_pgpath) | |
1255 | m->current_pgpath = NULL; | |
1256 | ||
b15546f9 | 1257 | dm_path_uevent(DM_UEVENT_PATH_FAILED, m->ti, |
91e968aa | 1258 | pgpath->path.dev->name, atomic_read(&m->nr_valid_paths)); |
b15546f9 | 1259 | |
fe9cf30e | 1260 | schedule_work(&m->trigger_event); |
1da177e4 LT |
1261 | |
1262 | out: | |
1263 | spin_unlock_irqrestore(&m->lock, flags); | |
1264 | ||
1265 | return 0; | |
1266 | } | |
1267 | ||
1268 | /* | |
1269 | * Reinstate a previously-failed path | |
1270 | */ | |
1271 | static int reinstate_path(struct pgpath *pgpath) | |
1272 | { | |
63d832c3 | 1273 | int r = 0, run_queue = 0; |
1da177e4 LT |
1274 | unsigned long flags; |
1275 | struct multipath *m = pgpath->pg->m; | |
91e968aa | 1276 | unsigned nr_valid_paths; |
1da177e4 LT |
1277 | |
1278 | spin_lock_irqsave(&m->lock, flags); | |
1279 | ||
6680073d | 1280 | if (pgpath->is_active) |
1da177e4 LT |
1281 | goto out; |
1282 | ||
ec31f3f7 | 1283 | DMWARN("Reinstating path %s.", pgpath->path.dev->name); |
1da177e4 LT |
1284 | |
1285 | r = pgpath->pg->ps.type->reinstate_path(&pgpath->pg->ps, &pgpath->path); | |
1286 | if (r) | |
1287 | goto out; | |
1288 | ||
be7d31cc | 1289 | pgpath->is_active = true; |
1da177e4 | 1290 | |
91e968aa MS |
1291 | nr_valid_paths = atomic_inc_return(&m->nr_valid_paths); |
1292 | if (nr_valid_paths == 1) { | |
e54f77dd | 1293 | m->current_pgpath = NULL; |
63d832c3 | 1294 | run_queue = 1; |
e54f77dd | 1295 | } else if (m->hw_handler_name && (m->current_pg == pgpath->pg)) { |
4e2d19e4 | 1296 | if (queue_work(kmpath_handlerd, &pgpath->activate_path.work)) |
91e968aa | 1297 | atomic_inc(&m->pg_init_in_progress); |
e54f77dd | 1298 | } |
1da177e4 | 1299 | |
b15546f9 | 1300 | dm_path_uevent(DM_UEVENT_PATH_REINSTATED, m->ti, |
91e968aa | 1301 | pgpath->path.dev->name, nr_valid_paths); |
b15546f9 | 1302 | |
fe9cf30e | 1303 | schedule_work(&m->trigger_event); |
1da177e4 LT |
1304 | |
1305 | out: | |
1306 | spin_unlock_irqrestore(&m->lock, flags); | |
76e33fe4 | 1307 | if (run_queue) { |
63d832c3 | 1308 | dm_table_run_md_queue_async(m->ti->table); |
7e48c768 | 1309 | process_queued_io_list(m); |
76e33fe4 | 1310 | } |
1da177e4 LT |
1311 | |
1312 | return r; | |
1313 | } | |
1314 | ||
1315 | /* | |
1316 | * Fail or reinstate all paths that match the provided struct dm_dev. | |
1317 | */ | |
1318 | static int action_dev(struct multipath *m, struct dm_dev *dev, | |
1319 | action_fn action) | |
1320 | { | |
19040c0b | 1321 | int r = -EINVAL; |
1da177e4 LT |
1322 | struct pgpath *pgpath; |
1323 | struct priority_group *pg; | |
1324 | ||
1325 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1326 | list_for_each_entry(pgpath, &pg->pgpaths, list) { | |
1327 | if (pgpath->path.dev == dev) | |
1328 | r = action(pgpath); | |
1329 | } | |
1330 | } | |
1331 | ||
1332 | return r; | |
1333 | } | |
1334 | ||
1335 | /* | |
1336 | * Temporarily try to avoid having to use the specified PG | |
1337 | */ | |
1338 | static void bypass_pg(struct multipath *m, struct priority_group *pg, | |
be7d31cc | 1339 | bool bypassed) |
1da177e4 LT |
1340 | { |
1341 | unsigned long flags; | |
1342 | ||
1343 | spin_lock_irqsave(&m->lock, flags); | |
1344 | ||
1345 | pg->bypassed = bypassed; | |
1346 | m->current_pgpath = NULL; | |
1347 | m->current_pg = NULL; | |
1348 | ||
1349 | spin_unlock_irqrestore(&m->lock, flags); | |
1350 | ||
fe9cf30e | 1351 | schedule_work(&m->trigger_event); |
1da177e4 LT |
1352 | } |
1353 | ||
1354 | /* | |
1355 | * Switch to using the specified PG from the next I/O that gets mapped | |
1356 | */ | |
1357 | static int switch_pg_num(struct multipath *m, const char *pgstr) | |
1358 | { | |
1359 | struct priority_group *pg; | |
1360 | unsigned pgnum; | |
1361 | unsigned long flags; | |
31998ef1 | 1362 | char dummy; |
1da177e4 | 1363 | |
31998ef1 | 1364 | if (!pgstr || (sscanf(pgstr, "%u%c", &pgnum, &dummy) != 1) || !pgnum || |
cc5bd925 | 1365 | !m->nr_priority_groups || (pgnum > m->nr_priority_groups)) { |
1da177e4 LT |
1366 | DMWARN("invalid PG number supplied to switch_pg_num"); |
1367 | return -EINVAL; | |
1368 | } | |
1369 | ||
1370 | spin_lock_irqsave(&m->lock, flags); | |
1371 | list_for_each_entry(pg, &m->priority_groups, list) { | |
be7d31cc | 1372 | pg->bypassed = false; |
1da177e4 LT |
1373 | if (--pgnum) |
1374 | continue; | |
1375 | ||
1376 | m->current_pgpath = NULL; | |
1377 | m->current_pg = NULL; | |
1378 | m->next_pg = pg; | |
1379 | } | |
1380 | spin_unlock_irqrestore(&m->lock, flags); | |
1381 | ||
fe9cf30e | 1382 | schedule_work(&m->trigger_event); |
1da177e4 LT |
1383 | return 0; |
1384 | } | |
1385 | ||
1386 | /* | |
1387 | * Set/clear bypassed status of a PG. | |
1388 | * PGs are numbered upwards from 1 in the order they were declared. | |
1389 | */ | |
be7d31cc | 1390 | static int bypass_pg_num(struct multipath *m, const char *pgstr, bool bypassed) |
1da177e4 LT |
1391 | { |
1392 | struct priority_group *pg; | |
1393 | unsigned pgnum; | |
31998ef1 | 1394 | char dummy; |
1da177e4 | 1395 | |
31998ef1 | 1396 | if (!pgstr || (sscanf(pgstr, "%u%c", &pgnum, &dummy) != 1) || !pgnum || |
cc5bd925 | 1397 | !m->nr_priority_groups || (pgnum > m->nr_priority_groups)) { |
1da177e4 LT |
1398 | DMWARN("invalid PG number supplied to bypass_pg"); |
1399 | return -EINVAL; | |
1400 | } | |
1401 | ||
1402 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1403 | if (!--pgnum) | |
1404 | break; | |
1405 | } | |
1406 | ||
1407 | bypass_pg(m, pg, bypassed); | |
1408 | return 0; | |
1409 | } | |
1410 | ||
c9e45581 DW |
1411 | /* |
1412 | * Should we retry pg_init immediately? | |
1413 | */ | |
be7d31cc | 1414 | static bool pg_init_limit_reached(struct multipath *m, struct pgpath *pgpath) |
c9e45581 DW |
1415 | { |
1416 | unsigned long flags; | |
be7d31cc | 1417 | bool limit_reached = false; |
c9e45581 DW |
1418 | |
1419 | spin_lock_irqsave(&m->lock, flags); | |
1420 | ||
91e968aa MS |
1421 | if (atomic_read(&m->pg_init_count) <= m->pg_init_retries && |
1422 | !test_bit(MPATHF_PG_INIT_DISABLED, &m->flags)) | |
518257b1 | 1423 | set_bit(MPATHF_PG_INIT_REQUIRED, &m->flags); |
c9e45581 | 1424 | else |
be7d31cc | 1425 | limit_reached = true; |
c9e45581 DW |
1426 | |
1427 | spin_unlock_irqrestore(&m->lock, flags); | |
1428 | ||
1429 | return limit_reached; | |
1430 | } | |
1431 | ||
3ae31f6a | 1432 | static void pg_init_done(void *data, int errors) |
cfae5c9b | 1433 | { |
83c0d5d5 | 1434 | struct pgpath *pgpath = data; |
cfae5c9b CS |
1435 | struct priority_group *pg = pgpath->pg; |
1436 | struct multipath *m = pg->m; | |
1437 | unsigned long flags; | |
be7d31cc | 1438 | bool delay_retry = false; |
cfae5c9b CS |
1439 | |
1440 | /* device or driver problems */ | |
1441 | switch (errors) { | |
1442 | case SCSI_DH_OK: | |
1443 | break; | |
1444 | case SCSI_DH_NOSYS: | |
1445 | if (!m->hw_handler_name) { | |
1446 | errors = 0; | |
1447 | break; | |
1448 | } | |
f7b934c8 MB |
1449 | DMERR("Could not failover the device: Handler scsi_dh_%s " |
1450 | "Error %d.", m->hw_handler_name, errors); | |
cfae5c9b CS |
1451 | /* |
1452 | * Fail path for now, so we do not ping pong | |
1453 | */ | |
1454 | fail_path(pgpath); | |
1455 | break; | |
1456 | case SCSI_DH_DEV_TEMP_BUSY: | |
1457 | /* | |
1458 | * Probably doing something like FW upgrade on the | |
1459 | * controller so try the other pg. | |
1460 | */ | |
be7d31cc | 1461 | bypass_pg(m, pg, true); |
cfae5c9b | 1462 | break; |
cfae5c9b | 1463 | case SCSI_DH_RETRY: |
4e2d19e4 CS |
1464 | /* Wait before retrying. */ |
1465 | delay_retry = 1; | |
cfae5c9b CS |
1466 | case SCSI_DH_IMM_RETRY: |
1467 | case SCSI_DH_RES_TEMP_UNAVAIL: | |
1468 | if (pg_init_limit_reached(m, pgpath)) | |
1469 | fail_path(pgpath); | |
1470 | errors = 0; | |
1471 | break; | |
ec31f3f7 | 1472 | case SCSI_DH_DEV_OFFLINED: |
cfae5c9b CS |
1473 | default: |
1474 | /* | |
1475 | * We probably do not want to fail the path for a device | |
1476 | * error, but this is what the old dm did. In future | |
1477 | * patches we can do more advanced handling. | |
1478 | */ | |
1479 | fail_path(pgpath); | |
1480 | } | |
1481 | ||
1482 | spin_lock_irqsave(&m->lock, flags); | |
1483 | if (errors) { | |
e54f77dd CS |
1484 | if (pgpath == m->current_pgpath) { |
1485 | DMERR("Could not failover device. Error %d.", errors); | |
1486 | m->current_pgpath = NULL; | |
1487 | m->current_pg = NULL; | |
1488 | } | |
518257b1 | 1489 | } else if (!test_bit(MPATHF_PG_INIT_REQUIRED, &m->flags)) |
be7d31cc | 1490 | pg->bypassed = false; |
cfae5c9b | 1491 | |
91e968aa | 1492 | if (atomic_dec_return(&m->pg_init_in_progress) > 0) |
d0259bf0 KU |
1493 | /* Activations of other paths are still on going */ |
1494 | goto out; | |
1495 | ||
518257b1 MS |
1496 | if (test_bit(MPATHF_PG_INIT_REQUIRED, &m->flags)) { |
1497 | if (delay_retry) | |
1498 | set_bit(MPATHF_PG_INIT_DELAY_RETRY, &m->flags); | |
1499 | else | |
1500 | clear_bit(MPATHF_PG_INIT_DELAY_RETRY, &m->flags); | |
1501 | ||
3e9f1be1 HR |
1502 | if (__pg_init_all_paths(m)) |
1503 | goto out; | |
1504 | } | |
518257b1 | 1505 | clear_bit(MPATHF_QUEUE_IO, &m->flags); |
d0259bf0 | 1506 | |
7e48c768 | 1507 | process_queued_io_list(m); |
76e33fe4 | 1508 | |
2bded7bd KU |
1509 | /* |
1510 | * Wake up any thread waiting to suspend. | |
1511 | */ | |
1512 | wake_up(&m->pg_init_wait); | |
1513 | ||
d0259bf0 | 1514 | out: |
cfae5c9b CS |
1515 | spin_unlock_irqrestore(&m->lock, flags); |
1516 | } | |
1517 | ||
bab7cfc7 CS |
1518 | static void activate_path(struct work_struct *work) |
1519 | { | |
e54f77dd | 1520 | struct pgpath *pgpath = |
4e2d19e4 | 1521 | container_of(work, struct pgpath, activate_path.work); |
f10e06b7 | 1522 | struct request_queue *q = bdev_get_queue(pgpath->path.dev->bdev); |
bab7cfc7 | 1523 | |
f10e06b7 MS |
1524 | if (pgpath->is_active && !blk_queue_dying(q)) |
1525 | scsi_dh_activate(q, pg_init_done, pgpath); | |
3a017509 HR |
1526 | else |
1527 | pg_init_done(pgpath, SCSI_DH_DEV_OFFLINED); | |
bab7cfc7 CS |
1528 | } |
1529 | ||
7e782af5 HR |
1530 | static int noretry_error(int error) |
1531 | { | |
1532 | switch (error) { | |
8ff232c1 HR |
1533 | case -EBADE: |
1534 | /* | |
1535 | * EBADE signals an reservation conflict. | |
1536 | * We shouldn't fail the path here as we can communicate with | |
1537 | * the target. We should failover to the next path, but in | |
1538 | * doing so we might be causing a ping-pong between paths. | |
1539 | * So just return the reservation conflict error. | |
1540 | */ | |
7e782af5 HR |
1541 | case -EOPNOTSUPP: |
1542 | case -EREMOTEIO: | |
1543 | case -EILSEQ: | |
1544 | case -ENODATA: | |
cc9d3c38 | 1545 | case -ENOSPC: |
7e782af5 HR |
1546 | return 1; |
1547 | } | |
1548 | ||
1549 | /* Anything else could be a path failure, so should be retried */ | |
1550 | return 0; | |
1551 | } | |
1552 | ||
1da177e4 LT |
1553 | /* |
1554 | * end_io handling | |
1555 | */ | |
f40c67f0 | 1556 | static int do_end_io(struct multipath *m, struct request *clone, |
028867ac | 1557 | int error, struct dm_mpath_io *mpio) |
1da177e4 | 1558 | { |
f40c67f0 KU |
1559 | /* |
1560 | * We don't queue any clone request inside the multipath target | |
1561 | * during end I/O handling, since those clone requests don't have | |
1562 | * bio clones. If we queue them inside the multipath target, | |
1563 | * we need to make bio clones, that requires memory allocation. | |
4cc96131 | 1564 | * (See drivers/md/dm-rq.c:end_clone_bio() about why the clone requests |
f40c67f0 KU |
1565 | * don't have bio clones.) |
1566 | * Instead of queueing the clone request here, we queue the original | |
1567 | * request into dm core, which will remake a clone request and | |
1568 | * clone bios for it and resubmit it later. | |
1569 | */ | |
1570 | int r = DM_ENDIO_REQUEUE; | |
1da177e4 | 1571 | |
f40c67f0 | 1572 | if (!error && !clone->errors) |
1da177e4 LT |
1573 | return 0; /* I/O complete */ |
1574 | ||
7eee4ae2 | 1575 | if (noretry_error(error)) |
959eb4e5 MS |
1576 | return error; |
1577 | ||
cfae5c9b CS |
1578 | if (mpio->pgpath) |
1579 | fail_path(mpio->pgpath); | |
1da177e4 | 1580 | |
91e968aa | 1581 | if (!atomic_read(&m->nr_valid_paths)) { |
518257b1 | 1582 | if (!test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) { |
76e33fe4 | 1583 | if (!must_push_back_rq(m)) |
751b2a7d | 1584 | r = -EIO; |
751b2a7d HR |
1585 | } |
1586 | } | |
1da177e4 | 1587 | |
f40c67f0 | 1588 | return r; |
1da177e4 LT |
1589 | } |
1590 | ||
f40c67f0 | 1591 | static int multipath_end_io(struct dm_target *ti, struct request *clone, |
1da177e4 LT |
1592 | int error, union map_info *map_context) |
1593 | { | |
028867ac | 1594 | struct multipath *m = ti->private; |
2eff1924 | 1595 | struct dm_mpath_io *mpio = get_mpio(map_context); |
a71a261f | 1596 | struct pgpath *pgpath; |
1da177e4 LT |
1597 | struct path_selector *ps; |
1598 | int r; | |
1599 | ||
466891f9 JN |
1600 | BUG_ON(!mpio); |
1601 | ||
2eff1924 | 1602 | r = do_end_io(m, clone, error, mpio); |
a71a261f | 1603 | pgpath = mpio->pgpath; |
1da177e4 LT |
1604 | if (pgpath) { |
1605 | ps = &pgpath->pg->ps; | |
1606 | if (ps->type->end_io) | |
02ab823f | 1607 | ps->type->end_io(ps, &pgpath->path, mpio->nr_bytes); |
1da177e4 | 1608 | } |
2eff1924 | 1609 | clear_request_fn_mpio(m, map_context); |
1da177e4 LT |
1610 | |
1611 | return r; | |
1612 | } | |
1613 | ||
76e33fe4 MS |
1614 | static int do_end_io_bio(struct multipath *m, struct bio *clone, |
1615 | int error, struct dm_mpath_io *mpio) | |
1616 | { | |
1617 | unsigned long flags; | |
1618 | ||
1619 | if (!error) | |
1620 | return 0; /* I/O complete */ | |
1621 | ||
1622 | if (noretry_error(error)) | |
1623 | return error; | |
1624 | ||
1625 | if (mpio->pgpath) | |
1626 | fail_path(mpio->pgpath); | |
1627 | ||
1628 | if (!atomic_read(&m->nr_valid_paths)) { | |
1629 | if (!test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) { | |
1630 | if (!must_push_back_bio(m)) | |
1631 | return -EIO; | |
1632 | return DM_ENDIO_REQUEUE; | |
76e33fe4 MS |
1633 | } |
1634 | } | |
1635 | ||
1636 | /* Queue for the daemon to resubmit */ | |
bf661be1 | 1637 | dm_bio_restore(get_bio_details_from_bio(clone), clone); |
76e33fe4 MS |
1638 | |
1639 | spin_lock_irqsave(&m->lock, flags); | |
1640 | bio_list_add(&m->queued_bios, clone); | |
1641 | spin_unlock_irqrestore(&m->lock, flags); | |
1642 | if (!test_bit(MPATHF_QUEUE_IO, &m->flags)) | |
1643 | queue_work(kmultipathd, &m->process_queued_bios); | |
1644 | ||
1645 | return DM_ENDIO_INCOMPLETE; | |
1646 | } | |
1647 | ||
1648 | static int multipath_end_io_bio(struct dm_target *ti, struct bio *clone, int error) | |
1649 | { | |
1650 | struct multipath *m = ti->private; | |
1651 | struct dm_mpath_io *mpio = get_mpio_from_bio(clone); | |
1652 | struct pgpath *pgpath; | |
1653 | struct path_selector *ps; | |
1654 | int r; | |
1655 | ||
1656 | BUG_ON(!mpio); | |
1657 | ||
1658 | r = do_end_io_bio(m, clone, error, mpio); | |
1659 | pgpath = mpio->pgpath; | |
1660 | if (pgpath) { | |
1661 | ps = &pgpath->pg->ps; | |
1662 | if (ps->type->end_io) | |
1663 | ps->type->end_io(ps, &pgpath->path, mpio->nr_bytes); | |
1664 | } | |
1665 | ||
1666 | return r; | |
1667 | } | |
1668 | ||
1da177e4 LT |
1669 | /* |
1670 | * Suspend can't complete until all the I/O is processed so if | |
436d4108 AK |
1671 | * the last path fails we must error any remaining I/O. |
1672 | * Note that if the freeze_bdev fails while suspending, the | |
1673 | * queue_if_no_path state is lost - userspace should reset it. | |
1da177e4 LT |
1674 | */ |
1675 | static void multipath_presuspend(struct dm_target *ti) | |
1676 | { | |
7943bd6d | 1677 | struct multipath *m = ti->private; |
1da177e4 | 1678 | |
be7d31cc | 1679 | queue_if_no_path(m, false, true); |
1da177e4 LT |
1680 | } |
1681 | ||
6df400ab KU |
1682 | static void multipath_postsuspend(struct dm_target *ti) |
1683 | { | |
6380f26f MA |
1684 | struct multipath *m = ti->private; |
1685 | ||
1686 | mutex_lock(&m->work_mutex); | |
2bded7bd | 1687 | flush_multipath_work(m); |
6380f26f | 1688 | mutex_unlock(&m->work_mutex); |
6df400ab KU |
1689 | } |
1690 | ||
436d4108 AK |
1691 | /* |
1692 | * Restore the queue_if_no_path setting. | |
1693 | */ | |
1da177e4 LT |
1694 | static void multipath_resume(struct dm_target *ti) |
1695 | { | |
7943bd6d | 1696 | struct multipath *m = ti->private; |
1814f2e3 | 1697 | unsigned long flags; |
1da177e4 | 1698 | |
1814f2e3 | 1699 | spin_lock_irqsave(&m->lock, flags); |
518257b1 MS |
1700 | if (test_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &m->flags)) |
1701 | set_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags); | |
1702 | else | |
1703 | clear_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags); | |
1814f2e3 | 1704 | spin_unlock_irqrestore(&m->lock, flags); |
1da177e4 LT |
1705 | } |
1706 | ||
1707 | /* | |
1708 | * Info output has the following format: | |
1709 | * num_multipath_feature_args [multipath_feature_args]* | |
1710 | * num_handler_status_args [handler_status_args]* | |
1711 | * num_groups init_group_number | |
1712 | * [A|D|E num_ps_status_args [ps_status_args]* | |
1713 | * num_paths num_selector_args | |
1714 | * [path_dev A|F fail_count [selector_args]* ]+ ]+ | |
1715 | * | |
1716 | * Table output has the following format (identical to the constructor string): | |
1717 | * num_feature_args [features_args]* | |
1718 | * num_handler_args hw_handler [hw_handler_args]* | |
1719 | * num_groups init_group_number | |
1720 | * [priority selector-name num_ps_args [ps_args]* | |
1721 | * num_paths num_selector_args [path_dev [selector_args]* ]+ ]+ | |
1722 | */ | |
fd7c092e MP |
1723 | static void multipath_status(struct dm_target *ti, status_type_t type, |
1724 | unsigned status_flags, char *result, unsigned maxlen) | |
1da177e4 LT |
1725 | { |
1726 | int sz = 0; | |
1727 | unsigned long flags; | |
7943bd6d | 1728 | struct multipath *m = ti->private; |
1da177e4 LT |
1729 | struct priority_group *pg; |
1730 | struct pgpath *p; | |
1731 | unsigned pg_num; | |
1732 | char state; | |
1733 | ||
1734 | spin_lock_irqsave(&m->lock, flags); | |
1735 | ||
1736 | /* Features */ | |
1737 | if (type == STATUSTYPE_INFO) | |
91e968aa MS |
1738 | DMEMIT("2 %u %u ", test_bit(MPATHF_QUEUE_IO, &m->flags), |
1739 | atomic_read(&m->pg_init_count)); | |
c9e45581 | 1740 | else { |
518257b1 | 1741 | DMEMIT("%u ", test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags) + |
4e2d19e4 | 1742 | (m->pg_init_retries > 0) * 2 + |
a58a935d | 1743 | (m->pg_init_delay_msecs != DM_PG_INIT_DELAY_DEFAULT) * 2 + |
e83068a5 MS |
1744 | test_bit(MPATHF_RETAIN_ATTACHED_HW_HANDLER, &m->flags) + |
1745 | (m->queue_mode != DM_TYPE_REQUEST_BASED) * 2); | |
1746 | ||
518257b1 | 1747 | if (test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) |
c9e45581 DW |
1748 | DMEMIT("queue_if_no_path "); |
1749 | if (m->pg_init_retries) | |
1750 | DMEMIT("pg_init_retries %u ", m->pg_init_retries); | |
4e2d19e4 CS |
1751 | if (m->pg_init_delay_msecs != DM_PG_INIT_DELAY_DEFAULT) |
1752 | DMEMIT("pg_init_delay_msecs %u ", m->pg_init_delay_msecs); | |
518257b1 | 1753 | if (test_bit(MPATHF_RETAIN_ATTACHED_HW_HANDLER, &m->flags)) |
a58a935d | 1754 | DMEMIT("retain_attached_hw_handler "); |
e83068a5 MS |
1755 | if (m->queue_mode != DM_TYPE_REQUEST_BASED) { |
1756 | switch(m->queue_mode) { | |
1757 | case DM_TYPE_BIO_BASED: | |
1758 | DMEMIT("queue_mode bio "); | |
1759 | break; | |
1760 | case DM_TYPE_MQ_REQUEST_BASED: | |
1761 | DMEMIT("queue_mode mq "); | |
1762 | break; | |
1763 | } | |
1764 | } | |
c9e45581 | 1765 | } |
1da177e4 | 1766 | |
cfae5c9b | 1767 | if (!m->hw_handler_name || type == STATUSTYPE_INFO) |
1da177e4 LT |
1768 | DMEMIT("0 "); |
1769 | else | |
cfae5c9b | 1770 | DMEMIT("1 %s ", m->hw_handler_name); |
1da177e4 LT |
1771 | |
1772 | DMEMIT("%u ", m->nr_priority_groups); | |
1773 | ||
1774 | if (m->next_pg) | |
1775 | pg_num = m->next_pg->pg_num; | |
1776 | else if (m->current_pg) | |
1777 | pg_num = m->current_pg->pg_num; | |
1778 | else | |
a490a07a | 1779 | pg_num = (m->nr_priority_groups ? 1 : 0); |
1da177e4 LT |
1780 | |
1781 | DMEMIT("%u ", pg_num); | |
1782 | ||
1783 | switch (type) { | |
1784 | case STATUSTYPE_INFO: | |
1785 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1786 | if (pg->bypassed) | |
1787 | state = 'D'; /* Disabled */ | |
1788 | else if (pg == m->current_pg) | |
1789 | state = 'A'; /* Currently Active */ | |
1790 | else | |
1791 | state = 'E'; /* Enabled */ | |
1792 | ||
1793 | DMEMIT("%c ", state); | |
1794 | ||
1795 | if (pg->ps.type->status) | |
1796 | sz += pg->ps.type->status(&pg->ps, NULL, type, | |
1797 | result + sz, | |
1798 | maxlen - sz); | |
1799 | else | |
1800 | DMEMIT("0 "); | |
1801 | ||
1802 | DMEMIT("%u %u ", pg->nr_pgpaths, | |
1803 | pg->ps.type->info_args); | |
1804 | ||
1805 | list_for_each_entry(p, &pg->pgpaths, list) { | |
1806 | DMEMIT("%s %s %u ", p->path.dev->name, | |
6680073d | 1807 | p->is_active ? "A" : "F", |
1da177e4 LT |
1808 | p->fail_count); |
1809 | if (pg->ps.type->status) | |
1810 | sz += pg->ps.type->status(&pg->ps, | |
1811 | &p->path, type, result + sz, | |
1812 | maxlen - sz); | |
1813 | } | |
1814 | } | |
1815 | break; | |
1816 | ||
1817 | case STATUSTYPE_TABLE: | |
1818 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1819 | DMEMIT("%s ", pg->ps.type->name); | |
1820 | ||
1821 | if (pg->ps.type->status) | |
1822 | sz += pg->ps.type->status(&pg->ps, NULL, type, | |
1823 | result + sz, | |
1824 | maxlen - sz); | |
1825 | else | |
1826 | DMEMIT("0 "); | |
1827 | ||
1828 | DMEMIT("%u %u ", pg->nr_pgpaths, | |
1829 | pg->ps.type->table_args); | |
1830 | ||
1831 | list_for_each_entry(p, &pg->pgpaths, list) { | |
1832 | DMEMIT("%s ", p->path.dev->name); | |
1833 | if (pg->ps.type->status) | |
1834 | sz += pg->ps.type->status(&pg->ps, | |
1835 | &p->path, type, result + sz, | |
1836 | maxlen - sz); | |
1837 | } | |
1838 | } | |
1839 | break; | |
1840 | } | |
1841 | ||
1842 | spin_unlock_irqrestore(&m->lock, flags); | |
1da177e4 LT |
1843 | } |
1844 | ||
1845 | static int multipath_message(struct dm_target *ti, unsigned argc, char **argv) | |
1846 | { | |
6380f26f | 1847 | int r = -EINVAL; |
1da177e4 | 1848 | struct dm_dev *dev; |
7943bd6d | 1849 | struct multipath *m = ti->private; |
1da177e4 LT |
1850 | action_fn action; |
1851 | ||
6380f26f MA |
1852 | mutex_lock(&m->work_mutex); |
1853 | ||
c2f3d24b KU |
1854 | if (dm_suspended(ti)) { |
1855 | r = -EBUSY; | |
1856 | goto out; | |
1857 | } | |
1858 | ||
1da177e4 | 1859 | if (argc == 1) { |
498f0103 | 1860 | if (!strcasecmp(argv[0], "queue_if_no_path")) { |
be7d31cc | 1861 | r = queue_if_no_path(m, true, false); |
6380f26f | 1862 | goto out; |
498f0103 | 1863 | } else if (!strcasecmp(argv[0], "fail_if_no_path")) { |
be7d31cc | 1864 | r = queue_if_no_path(m, false, false); |
6380f26f MA |
1865 | goto out; |
1866 | } | |
1da177e4 LT |
1867 | } |
1868 | ||
6380f26f | 1869 | if (argc != 2) { |
a356e426 | 1870 | DMWARN("Invalid multipath message arguments. Expected 2 arguments, got %d.", argc); |
6380f26f MA |
1871 | goto out; |
1872 | } | |
1da177e4 | 1873 | |
498f0103 | 1874 | if (!strcasecmp(argv[0], "disable_group")) { |
be7d31cc | 1875 | r = bypass_pg_num(m, argv[1], true); |
6380f26f | 1876 | goto out; |
498f0103 | 1877 | } else if (!strcasecmp(argv[0], "enable_group")) { |
be7d31cc | 1878 | r = bypass_pg_num(m, argv[1], false); |
6380f26f | 1879 | goto out; |
498f0103 | 1880 | } else if (!strcasecmp(argv[0], "switch_group")) { |
6380f26f MA |
1881 | r = switch_pg_num(m, argv[1]); |
1882 | goto out; | |
498f0103 | 1883 | } else if (!strcasecmp(argv[0], "reinstate_path")) |
1da177e4 | 1884 | action = reinstate_path; |
498f0103 | 1885 | else if (!strcasecmp(argv[0], "fail_path")) |
1da177e4 | 1886 | action = fail_path; |
6380f26f | 1887 | else { |
a356e426 | 1888 | DMWARN("Unrecognised multipath message received: %s", argv[0]); |
6380f26f MA |
1889 | goto out; |
1890 | } | |
1da177e4 | 1891 | |
8215d6ec | 1892 | r = dm_get_device(ti, argv[1], dm_table_get_mode(ti->table), &dev); |
1da177e4 | 1893 | if (r) { |
72d94861 | 1894 | DMWARN("message: error getting device %s", |
1da177e4 | 1895 | argv[1]); |
6380f26f | 1896 | goto out; |
1da177e4 LT |
1897 | } |
1898 | ||
1899 | r = action_dev(m, dev, action); | |
1900 | ||
1901 | dm_put_device(ti, dev); | |
1902 | ||
6380f26f MA |
1903 | out: |
1904 | mutex_unlock(&m->work_mutex); | |
1da177e4 | 1905 | return r; |
1da177e4 LT |
1906 | } |
1907 | ||
e56f81e0 CH |
1908 | static int multipath_prepare_ioctl(struct dm_target *ti, |
1909 | struct block_device **bdev, fmode_t *mode) | |
9af4aa30 | 1910 | { |
35991652 | 1911 | struct multipath *m = ti->private; |
2da1610a | 1912 | struct pgpath *current_pgpath; |
35991652 MP |
1913 | int r; |
1914 | ||
2da1610a MS |
1915 | current_pgpath = lockless_dereference(m->current_pgpath); |
1916 | if (!current_pgpath) | |
1917 | current_pgpath = choose_pgpath(m, 0); | |
9af4aa30 | 1918 | |
2da1610a | 1919 | if (current_pgpath) { |
518257b1 | 1920 | if (!test_bit(MPATHF_QUEUE_IO, &m->flags)) { |
2da1610a MS |
1921 | *bdev = current_pgpath->path.dev->bdev; |
1922 | *mode = current_pgpath->path.dev->mode; | |
43e43c9e JN |
1923 | r = 0; |
1924 | } else { | |
1925 | /* pg_init has not started or completed */ | |
1926 | r = -ENOTCONN; | |
1927 | } | |
1928 | } else { | |
1929 | /* No path is available */ | |
518257b1 | 1930 | if (test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) |
43e43c9e JN |
1931 | r = -ENOTCONN; |
1932 | else | |
1933 | r = -EIO; | |
e90dae1f | 1934 | } |
9af4aa30 | 1935 | |
5bbbfdf6 | 1936 | if (r == -ENOTCONN) { |
2da1610a | 1937 | if (!lockless_dereference(m->current_pg)) { |
3e9f1be1 | 1938 | /* Path status changed, redo selection */ |
2da1610a | 1939 | (void) choose_pgpath(m, 0); |
3e9f1be1 | 1940 | } |
518257b1 | 1941 | if (test_bit(MPATHF_PG_INIT_REQUIRED, &m->flags)) |
2da1610a | 1942 | pg_init_all_paths(m); |
63d832c3 | 1943 | dm_table_run_md_queue_async(m->ti->table); |
7e48c768 | 1944 | process_queued_io_list(m); |
3e9f1be1 | 1945 | } |
35991652 | 1946 | |
e56f81e0 CH |
1947 | /* |
1948 | * Only pass ioctls through if the device sizes match exactly. | |
1949 | */ | |
1950 | if (!r && ti->len != i_size_read((*bdev)->bd_inode) >> SECTOR_SHIFT) | |
1951 | return 1; | |
1952 | return r; | |
9af4aa30 MB |
1953 | } |
1954 | ||
af4874e0 MS |
1955 | static int multipath_iterate_devices(struct dm_target *ti, |
1956 | iterate_devices_callout_fn fn, void *data) | |
1957 | { | |
1958 | struct multipath *m = ti->private; | |
1959 | struct priority_group *pg; | |
1960 | struct pgpath *p; | |
1961 | int ret = 0; | |
1962 | ||
1963 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1964 | list_for_each_entry(p, &pg->pgpaths, list) { | |
5dea271b | 1965 | ret = fn(ti, p->path.dev, ti->begin, ti->len, data); |
af4874e0 MS |
1966 | if (ret) |
1967 | goto out; | |
1968 | } | |
1969 | } | |
1970 | ||
1971 | out: | |
1972 | return ret; | |
1973 | } | |
1974 | ||
9f54cec5 | 1975 | static int pgpath_busy(struct pgpath *pgpath) |
f40c67f0 KU |
1976 | { |
1977 | struct request_queue *q = bdev_get_queue(pgpath->path.dev->bdev); | |
1978 | ||
52b09914 | 1979 | return blk_lld_busy(q); |
f40c67f0 KU |
1980 | } |
1981 | ||
1982 | /* | |
1983 | * We return "busy", only when we can map I/Os but underlying devices | |
1984 | * are busy (so even if we map I/Os now, the I/Os will wait on | |
1985 | * the underlying queue). | |
1986 | * In other words, if we want to kill I/Os or queue them inside us | |
1987 | * due to map unavailability, we don't return "busy". Otherwise, | |
1988 | * dm core won't give us the I/Os and we can't do what we want. | |
1989 | */ | |
1990 | static int multipath_busy(struct dm_target *ti) | |
1991 | { | |
be7d31cc | 1992 | bool busy = false, has_active = false; |
f40c67f0 | 1993 | struct multipath *m = ti->private; |
2da1610a | 1994 | struct priority_group *pg, *next_pg; |
f40c67f0 | 1995 | struct pgpath *pgpath; |
f40c67f0 | 1996 | |
b88efd43 MS |
1997 | /* pg_init in progress */ |
1998 | if (atomic_read(&m->pg_init_in_progress)) | |
2da1610a MS |
1999 | return true; |
2000 | ||
b88efd43 MS |
2001 | /* no paths available, for blk-mq: rely on IO mapping to delay requeue */ |
2002 | if (!atomic_read(&m->nr_valid_paths) && test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) | |
2003 | return (m->queue_mode != DM_TYPE_MQ_REQUEST_BASED); | |
2004 | ||
f40c67f0 | 2005 | /* Guess which priority_group will be used at next mapping time */ |
2da1610a MS |
2006 | pg = lockless_dereference(m->current_pg); |
2007 | next_pg = lockless_dereference(m->next_pg); | |
2008 | if (unlikely(!lockless_dereference(m->current_pgpath) && next_pg)) | |
2009 | pg = next_pg; | |
2010 | ||
2011 | if (!pg) { | |
f40c67f0 KU |
2012 | /* |
2013 | * We don't know which pg will be used at next mapping time. | |
2da1610a | 2014 | * We don't call choose_pgpath() here to avoid to trigger |
f40c67f0 KU |
2015 | * pg_init just by busy checking. |
2016 | * So we don't know whether underlying devices we will be using | |
2017 | * at next mapping time are busy or not. Just try mapping. | |
2018 | */ | |
2da1610a MS |
2019 | return busy; |
2020 | } | |
f40c67f0 KU |
2021 | |
2022 | /* | |
2023 | * If there is one non-busy active path at least, the path selector | |
2024 | * will be able to select it. So we consider such a pg as not busy. | |
2025 | */ | |
be7d31cc | 2026 | busy = true; |
2da1610a | 2027 | list_for_each_entry(pgpath, &pg->pgpaths, list) { |
f40c67f0 | 2028 | if (pgpath->is_active) { |
be7d31cc | 2029 | has_active = true; |
9f54cec5 | 2030 | if (!pgpath_busy(pgpath)) { |
be7d31cc | 2031 | busy = false; |
f40c67f0 KU |
2032 | break; |
2033 | } | |
2034 | } | |
2da1610a | 2035 | } |
f40c67f0 | 2036 | |
2da1610a | 2037 | if (!has_active) { |
f40c67f0 KU |
2038 | /* |
2039 | * No active path in this pg, so this pg won't be used and | |
2040 | * the current_pg will be changed at next mapping time. | |
2041 | * We need to try mapping to determine it. | |
2042 | */ | |
be7d31cc | 2043 | busy = false; |
2da1610a | 2044 | } |
f40c67f0 KU |
2045 | |
2046 | return busy; | |
2047 | } | |
2048 | ||
1da177e4 LT |
2049 | /*----------------------------------------------------------------- |
2050 | * Module setup | |
2051 | *---------------------------------------------------------------*/ | |
2052 | static struct target_type multipath_target = { | |
2053 | .name = "multipath", | |
e83068a5 | 2054 | .version = {1, 12, 0}, |
16f12266 | 2055 | .features = DM_TARGET_SINGLETON | DM_TARGET_IMMUTABLE, |
1da177e4 LT |
2056 | .module = THIS_MODULE, |
2057 | .ctr = multipath_ctr, | |
2058 | .dtr = multipath_dtr, | |
f40c67f0 | 2059 | .map_rq = multipath_map, |
e5863d9a MS |
2060 | .clone_and_map_rq = multipath_clone_and_map, |
2061 | .release_clone_rq = multipath_release_clone, | |
f40c67f0 | 2062 | .rq_end_io = multipath_end_io, |
76e33fe4 MS |
2063 | .map = multipath_map_bio, |
2064 | .end_io = multipath_end_io_bio, | |
2065 | .presuspend = multipath_presuspend, | |
2066 | .postsuspend = multipath_postsuspend, | |
2067 | .resume = multipath_resume, | |
2068 | .status = multipath_status, | |
2069 | .message = multipath_message, | |
2070 | .prepare_ioctl = multipath_prepare_ioctl, | |
2071 | .iterate_devices = multipath_iterate_devices, | |
2072 | .busy = multipath_busy, | |
2073 | }; | |
2074 | ||
1da177e4 LT |
2075 | static int __init dm_multipath_init(void) |
2076 | { | |
2077 | int r; | |
2078 | ||
76e33fe4 | 2079 | /* allocate a slab for the dm_mpath_ios */ |
028867ac | 2080 | _mpio_cache = KMEM_CACHE(dm_mpath_io, 0); |
1da177e4 LT |
2081 | if (!_mpio_cache) |
2082 | return -ENOMEM; | |
2083 | ||
2084 | r = dm_register_target(&multipath_target); | |
2085 | if (r < 0) { | |
76e33fe4 | 2086 | DMERR("request-based register failed %d", r); |
ff658e9c JT |
2087 | r = -EINVAL; |
2088 | goto bad_register_target; | |
1da177e4 LT |
2089 | } |
2090 | ||
4d4d66ab | 2091 | kmultipathd = alloc_workqueue("kmpathd", WQ_MEM_RECLAIM, 0); |
c557308e | 2092 | if (!kmultipathd) { |
0cd33124 | 2093 | DMERR("failed to create workqueue kmpathd"); |
ff658e9c JT |
2094 | r = -ENOMEM; |
2095 | goto bad_alloc_kmultipathd; | |
c557308e AK |
2096 | } |
2097 | ||
bab7cfc7 CS |
2098 | /* |
2099 | * A separate workqueue is used to handle the device handlers | |
2100 | * to avoid overloading existing workqueue. Overloading the | |
2101 | * old workqueue would also create a bottleneck in the | |
2102 | * path of the storage hardware device activation. | |
2103 | */ | |
4d4d66ab TH |
2104 | kmpath_handlerd = alloc_ordered_workqueue("kmpath_handlerd", |
2105 | WQ_MEM_RECLAIM); | |
bab7cfc7 CS |
2106 | if (!kmpath_handlerd) { |
2107 | DMERR("failed to create workqueue kmpath_handlerd"); | |
ff658e9c JT |
2108 | r = -ENOMEM; |
2109 | goto bad_alloc_kmpath_handlerd; | |
bab7cfc7 CS |
2110 | } |
2111 | ||
ff658e9c JT |
2112 | return 0; |
2113 | ||
2114 | bad_alloc_kmpath_handlerd: | |
2115 | destroy_workqueue(kmultipathd); | |
2116 | bad_alloc_kmultipathd: | |
2117 | dm_unregister_target(&multipath_target); | |
2118 | bad_register_target: | |
2119 | kmem_cache_destroy(_mpio_cache); | |
2120 | ||
1da177e4 LT |
2121 | return r; |
2122 | } | |
2123 | ||
2124 | static void __exit dm_multipath_exit(void) | |
2125 | { | |
bab7cfc7 | 2126 | destroy_workqueue(kmpath_handlerd); |
c557308e AK |
2127 | destroy_workqueue(kmultipathd); |
2128 | ||
10d3bd09 | 2129 | dm_unregister_target(&multipath_target); |
1da177e4 LT |
2130 | kmem_cache_destroy(_mpio_cache); |
2131 | } | |
2132 | ||
1da177e4 LT |
2133 | module_init(dm_multipath_init); |
2134 | module_exit(dm_multipath_exit); | |
2135 | ||
2136 | MODULE_DESCRIPTION(DM_NAME " multipath target"); | |
2137 | MODULE_AUTHOR("Sistina Software <dm-devel@redhat.com>"); | |
2138 | MODULE_LICENSE("GPL"); |