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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * Copyright (C) 2003 Sistina Software Limited. | |
3 | * Copyright (C) 2004-2005 Red Hat, Inc. All rights reserved. | |
4 | * | |
5 | * This file is released under the GPL. | |
6 | */ | |
7 | ||
586e80e6 MP |
8 | #include <linux/device-mapper.h> |
9 | ||
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) { | |
54cd640d | 852 | /* |
853 | * Clear any hw_handler_params associated with a | |
854 | * handler that isn't already attached. | |
855 | */ | |
856 | if (m->hw_handler_name && strcmp(attached_handler_name, m->hw_handler_name)) { | |
857 | kfree(m->hw_handler_params); | |
858 | m->hw_handler_params = NULL; | |
859 | } | |
860 | ||
a58a935d MS |
861 | /* |
862 | * Reset hw_handler_name to match the attached handler | |
a58a935d MS |
863 | * |
864 | * NB. This modifies the table line to show the actual | |
865 | * handler instead of the original table passed in. | |
866 | */ | |
867 | kfree(m->hw_handler_name); | |
868 | m->hw_handler_name = attached_handler_name; | |
a58a935d MS |
869 | } |
870 | } | |
a0cf7ea9 | 871 | |
a58a935d | 872 | if (m->hw_handler_name) { |
a0cf7ea9 HR |
873 | r = scsi_dh_attach(q, m->hw_handler_name); |
874 | if (r == -EBUSY) { | |
1bab0de0 | 875 | char b[BDEVNAME_SIZE]; |
a0cf7ea9 | 876 | |
1bab0de0 CH |
877 | printk(KERN_INFO "dm-mpath: retaining handler on device %s\n", |
878 | bdevname(p->path.dev->bdev, b)); | |
879 | goto retain; | |
880 | } | |
ae11b1b3 | 881 | if (r < 0) { |
a0cf7ea9 | 882 | ti->error = "error attaching hardware handler"; |
ae11b1b3 HR |
883 | dm_put_device(ti, p->path.dev); |
884 | goto bad; | |
885 | } | |
2bfd2e13 CS |
886 | |
887 | if (m->hw_handler_params) { | |
888 | r = scsi_dh_set_params(q, m->hw_handler_params); | |
889 | if (r < 0) { | |
890 | ti->error = "unable to set hardware " | |
891 | "handler parameters"; | |
2bfd2e13 CS |
892 | dm_put_device(ti, p->path.dev); |
893 | goto bad; | |
894 | } | |
895 | } | |
ae11b1b3 HR |
896 | } |
897 | ||
1da177e4 LT |
898 | r = ps->type->add_path(ps, &p->path, as->argc, as->argv, &ti->error); |
899 | if (r) { | |
900 | dm_put_device(ti, p->path.dev); | |
901 | goto bad; | |
902 | } | |
903 | ||
904 | return p; | |
905 | ||
906 | bad: | |
907 | free_pgpath(p); | |
01460f35 | 908 | return ERR_PTR(r); |
1da177e4 LT |
909 | } |
910 | ||
498f0103 | 911 | static struct priority_group *parse_priority_group(struct dm_arg_set *as, |
28f16c20 | 912 | struct multipath *m) |
1da177e4 | 913 | { |
498f0103 | 914 | static struct dm_arg _args[] = { |
72d94861 AK |
915 | {1, 1024, "invalid number of paths"}, |
916 | {0, 1024, "invalid number of selector args"} | |
1da177e4 LT |
917 | }; |
918 | ||
919 | int r; | |
498f0103 | 920 | unsigned i, nr_selector_args, nr_args; |
1da177e4 | 921 | struct priority_group *pg; |
28f16c20 | 922 | struct dm_target *ti = m->ti; |
1da177e4 LT |
923 | |
924 | if (as->argc < 2) { | |
925 | as->argc = 0; | |
01460f35 BM |
926 | ti->error = "not enough priority group arguments"; |
927 | return ERR_PTR(-EINVAL); | |
1da177e4 LT |
928 | } |
929 | ||
930 | pg = alloc_priority_group(); | |
931 | if (!pg) { | |
72d94861 | 932 | ti->error = "couldn't allocate priority group"; |
01460f35 | 933 | return ERR_PTR(-ENOMEM); |
1da177e4 LT |
934 | } |
935 | pg->m = m; | |
936 | ||
937 | r = parse_path_selector(as, pg, ti); | |
938 | if (r) | |
939 | goto bad; | |
940 | ||
941 | /* | |
942 | * read the paths | |
943 | */ | |
498f0103 | 944 | r = dm_read_arg(_args, as, &pg->nr_pgpaths, &ti->error); |
1da177e4 LT |
945 | if (r) |
946 | goto bad; | |
947 | ||
498f0103 | 948 | r = dm_read_arg(_args + 1, as, &nr_selector_args, &ti->error); |
1da177e4 LT |
949 | if (r) |
950 | goto bad; | |
951 | ||
498f0103 | 952 | nr_args = 1 + nr_selector_args; |
1da177e4 LT |
953 | for (i = 0; i < pg->nr_pgpaths; i++) { |
954 | struct pgpath *pgpath; | |
498f0103 | 955 | struct dm_arg_set path_args; |
1da177e4 | 956 | |
498f0103 | 957 | if (as->argc < nr_args) { |
148acff6 | 958 | ti->error = "not enough path parameters"; |
6bbf79a1 | 959 | r = -EINVAL; |
1da177e4 | 960 | goto bad; |
148acff6 | 961 | } |
1da177e4 | 962 | |
498f0103 | 963 | path_args.argc = nr_args; |
1da177e4 LT |
964 | path_args.argv = as->argv; |
965 | ||
966 | pgpath = parse_path(&path_args, &pg->ps, ti); | |
01460f35 BM |
967 | if (IS_ERR(pgpath)) { |
968 | r = PTR_ERR(pgpath); | |
1da177e4 | 969 | goto bad; |
01460f35 | 970 | } |
1da177e4 LT |
971 | |
972 | pgpath->pg = pg; | |
973 | list_add_tail(&pgpath->list, &pg->pgpaths); | |
498f0103 | 974 | dm_consume_args(as, nr_args); |
1da177e4 LT |
975 | } |
976 | ||
977 | return pg; | |
978 | ||
979 | bad: | |
980 | free_priority_group(pg, ti); | |
01460f35 | 981 | return ERR_PTR(r); |
1da177e4 LT |
982 | } |
983 | ||
498f0103 | 984 | static int parse_hw_handler(struct dm_arg_set *as, struct multipath *m) |
1da177e4 | 985 | { |
1da177e4 | 986 | unsigned hw_argc; |
2bfd2e13 | 987 | int ret; |
28f16c20 | 988 | struct dm_target *ti = m->ti; |
1da177e4 | 989 | |
498f0103 | 990 | static struct dm_arg _args[] = { |
72d94861 | 991 | {0, 1024, "invalid number of hardware handler args"}, |
1da177e4 LT |
992 | }; |
993 | ||
498f0103 | 994 | if (dm_read_arg_group(_args, as, &hw_argc, &ti->error)) |
1da177e4 LT |
995 | return -EINVAL; |
996 | ||
997 | if (!hw_argc) | |
998 | return 0; | |
999 | ||
e83068a5 | 1000 | if (m->queue_mode == DM_TYPE_BIO_BASED) { |
76e33fe4 MS |
1001 | dm_consume_args(as, hw_argc); |
1002 | DMERR("bio-based multipath doesn't allow hardware handler args"); | |
1003 | return 0; | |
1004 | } | |
1005 | ||
498f0103 | 1006 | m->hw_handler_name = kstrdup(dm_shift_arg(as), GFP_KERNEL); |
f97dc421 | 1007 | if (!m->hw_handler_name) |
1008 | return -EINVAL; | |
14e98c5c | 1009 | |
2bfd2e13 CS |
1010 | if (hw_argc > 1) { |
1011 | char *p; | |
1012 | int i, j, len = 4; | |
1013 | ||
1014 | for (i = 0; i <= hw_argc - 2; i++) | |
1015 | len += strlen(as->argv[i]) + 1; | |
1016 | p = m->hw_handler_params = kzalloc(len, GFP_KERNEL); | |
1017 | if (!p) { | |
1018 | ti->error = "memory allocation failed"; | |
1019 | ret = -ENOMEM; | |
1020 | goto fail; | |
1021 | } | |
1022 | j = sprintf(p, "%d", hw_argc - 1); | |
1023 | for (i = 0, p+=j+1; i <= hw_argc - 2; i++, p+=j+1) | |
1024 | j = sprintf(p, "%s", as->argv[i]); | |
1025 | } | |
498f0103 | 1026 | dm_consume_args(as, hw_argc - 1); |
1da177e4 LT |
1027 | |
1028 | return 0; | |
2bfd2e13 CS |
1029 | fail: |
1030 | kfree(m->hw_handler_name); | |
1031 | m->hw_handler_name = NULL; | |
1032 | return ret; | |
1da177e4 LT |
1033 | } |
1034 | ||
498f0103 | 1035 | static int parse_features(struct dm_arg_set *as, struct multipath *m) |
1da177e4 LT |
1036 | { |
1037 | int r; | |
1038 | unsigned argc; | |
28f16c20 | 1039 | struct dm_target *ti = m->ti; |
498f0103 | 1040 | const char *arg_name; |
1da177e4 | 1041 | |
498f0103 | 1042 | static struct dm_arg _args[] = { |
e83068a5 | 1043 | {0, 8, "invalid number of feature args"}, |
c9e45581 | 1044 | {1, 50, "pg_init_retries must be between 1 and 50"}, |
4e2d19e4 | 1045 | {0, 60000, "pg_init_delay_msecs must be between 0 and 60000"}, |
1da177e4 LT |
1046 | }; |
1047 | ||
498f0103 | 1048 | r = dm_read_arg_group(_args, as, &argc, &ti->error); |
1da177e4 LT |
1049 | if (r) |
1050 | return -EINVAL; | |
1051 | ||
1052 | if (!argc) | |
1053 | return 0; | |
1054 | ||
c9e45581 | 1055 | do { |
498f0103 | 1056 | arg_name = dm_shift_arg(as); |
c9e45581 DW |
1057 | argc--; |
1058 | ||
498f0103 | 1059 | if (!strcasecmp(arg_name, "queue_if_no_path")) { |
be7d31cc | 1060 | r = queue_if_no_path(m, true, false); |
c9e45581 DW |
1061 | continue; |
1062 | } | |
1063 | ||
a58a935d | 1064 | if (!strcasecmp(arg_name, "retain_attached_hw_handler")) { |
518257b1 | 1065 | set_bit(MPATHF_RETAIN_ATTACHED_HW_HANDLER, &m->flags); |
a58a935d MS |
1066 | continue; |
1067 | } | |
1068 | ||
498f0103 | 1069 | if (!strcasecmp(arg_name, "pg_init_retries") && |
c9e45581 | 1070 | (argc >= 1)) { |
498f0103 | 1071 | r = dm_read_arg(_args + 1, as, &m->pg_init_retries, &ti->error); |
c9e45581 DW |
1072 | argc--; |
1073 | continue; | |
1074 | } | |
1075 | ||
498f0103 | 1076 | if (!strcasecmp(arg_name, "pg_init_delay_msecs") && |
4e2d19e4 | 1077 | (argc >= 1)) { |
498f0103 | 1078 | r = dm_read_arg(_args + 2, as, &m->pg_init_delay_msecs, &ti->error); |
4e2d19e4 CS |
1079 | argc--; |
1080 | continue; | |
1081 | } | |
1082 | ||
e83068a5 MS |
1083 | if (!strcasecmp(arg_name, "queue_mode") && |
1084 | (argc >= 1)) { | |
1085 | const char *queue_mode_name = dm_shift_arg(as); | |
1086 | ||
1087 | if (!strcasecmp(queue_mode_name, "bio")) | |
1088 | m->queue_mode = DM_TYPE_BIO_BASED; | |
1089 | else if (!strcasecmp(queue_mode_name, "rq")) | |
1090 | m->queue_mode = DM_TYPE_REQUEST_BASED; | |
1091 | else if (!strcasecmp(queue_mode_name, "mq")) | |
1092 | m->queue_mode = DM_TYPE_MQ_REQUEST_BASED; | |
1093 | else { | |
1094 | ti->error = "Unknown 'queue_mode' requested"; | |
1095 | r = -EINVAL; | |
1096 | } | |
1097 | argc--; | |
1098 | continue; | |
1099 | } | |
1100 | ||
1da177e4 | 1101 | ti->error = "Unrecognised multipath feature request"; |
c9e45581 DW |
1102 | r = -EINVAL; |
1103 | } while (argc && !r); | |
1104 | ||
1105 | return r; | |
1da177e4 LT |
1106 | } |
1107 | ||
e83068a5 | 1108 | static int multipath_ctr(struct dm_target *ti, unsigned argc, char **argv) |
1da177e4 | 1109 | { |
498f0103 MS |
1110 | /* target arguments */ |
1111 | static struct dm_arg _args[] = { | |
a490a07a MS |
1112 | {0, 1024, "invalid number of priority groups"}, |
1113 | {0, 1024, "invalid initial priority group number"}, | |
1da177e4 LT |
1114 | }; |
1115 | ||
1116 | int r; | |
1117 | struct multipath *m; | |
498f0103 | 1118 | struct dm_arg_set as; |
1da177e4 LT |
1119 | unsigned pg_count = 0; |
1120 | unsigned next_pg_num; | |
1121 | ||
1122 | as.argc = argc; | |
1123 | as.argv = argv; | |
1124 | ||
e83068a5 | 1125 | m = alloc_multipath(ti); |
1da177e4 | 1126 | if (!m) { |
72d94861 | 1127 | ti->error = "can't allocate multipath"; |
1da177e4 LT |
1128 | return -EINVAL; |
1129 | } | |
1130 | ||
28f16c20 | 1131 | r = parse_features(&as, m); |
1da177e4 LT |
1132 | if (r) |
1133 | goto bad; | |
1134 | ||
e83068a5 MS |
1135 | r = alloc_multipath_stage2(ti, m); |
1136 | if (r) | |
1137 | goto bad; | |
1138 | ||
28f16c20 | 1139 | r = parse_hw_handler(&as, m); |
1da177e4 LT |
1140 | if (r) |
1141 | goto bad; | |
1142 | ||
498f0103 | 1143 | r = dm_read_arg(_args, &as, &m->nr_priority_groups, &ti->error); |
1da177e4 LT |
1144 | if (r) |
1145 | goto bad; | |
1146 | ||
498f0103 | 1147 | r = dm_read_arg(_args + 1, &as, &next_pg_num, &ti->error); |
1da177e4 LT |
1148 | if (r) |
1149 | goto bad; | |
1150 | ||
a490a07a MS |
1151 | if ((!m->nr_priority_groups && next_pg_num) || |
1152 | (m->nr_priority_groups && !next_pg_num)) { | |
1153 | ti->error = "invalid initial priority group"; | |
1154 | r = -EINVAL; | |
1155 | goto bad; | |
1156 | } | |
1157 | ||
1da177e4 LT |
1158 | /* parse the priority groups */ |
1159 | while (as.argc) { | |
1160 | struct priority_group *pg; | |
91e968aa | 1161 | unsigned nr_valid_paths = atomic_read(&m->nr_valid_paths); |
1da177e4 | 1162 | |
28f16c20 | 1163 | pg = parse_priority_group(&as, m); |
01460f35 BM |
1164 | if (IS_ERR(pg)) { |
1165 | r = PTR_ERR(pg); | |
1da177e4 LT |
1166 | goto bad; |
1167 | } | |
1168 | ||
91e968aa MS |
1169 | nr_valid_paths += pg->nr_pgpaths; |
1170 | atomic_set(&m->nr_valid_paths, nr_valid_paths); | |
1171 | ||
1da177e4 LT |
1172 | list_add_tail(&pg->list, &m->priority_groups); |
1173 | pg_count++; | |
1174 | pg->pg_num = pg_count; | |
1175 | if (!--next_pg_num) | |
1176 | m->next_pg = pg; | |
1177 | } | |
1178 | ||
1179 | if (pg_count != m->nr_priority_groups) { | |
72d94861 | 1180 | ti->error = "priority group count mismatch"; |
1da177e4 LT |
1181 | r = -EINVAL; |
1182 | goto bad; | |
1183 | } | |
1184 | ||
55a62eef AK |
1185 | ti->num_flush_bios = 1; |
1186 | ti->num_discard_bios = 1; | |
042bcef8 | 1187 | ti->num_write_same_bios = 1; |
e83068a5 | 1188 | if (m->queue_mode == DM_TYPE_BIO_BASED) |
bf661be1 | 1189 | ti->per_io_data_size = multipath_per_bio_data_size(); |
e83068a5 | 1190 | else if (m->queue_mode == DM_TYPE_MQ_REQUEST_BASED) |
8637a6bf | 1191 | ti->per_io_data_size = sizeof(struct dm_mpath_io); |
8627921f | 1192 | |
1da177e4 LT |
1193 | return 0; |
1194 | ||
1195 | bad: | |
1196 | free_multipath(m); | |
1197 | return r; | |
1198 | } | |
1199 | ||
2bded7bd KU |
1200 | static void multipath_wait_for_pg_init_completion(struct multipath *m) |
1201 | { | |
9f4c3f87 | 1202 | DEFINE_WAIT(wait); |
2bded7bd KU |
1203 | |
1204 | while (1) { | |
9f4c3f87 | 1205 | prepare_to_wait(&m->pg_init_wait, &wait, TASK_UNINTERRUPTIBLE); |
2bded7bd | 1206 | |
91e968aa | 1207 | if (!atomic_read(&m->pg_init_in_progress)) |
2bded7bd | 1208 | break; |
2bded7bd KU |
1209 | |
1210 | io_schedule(); | |
1211 | } | |
9f4c3f87 | 1212 | finish_wait(&m->pg_init_wait, &wait); |
2bded7bd KU |
1213 | } |
1214 | ||
1215 | static void flush_multipath_work(struct multipath *m) | |
1da177e4 | 1216 | { |
518257b1 MS |
1217 | set_bit(MPATHF_PG_INIT_DISABLED, &m->flags); |
1218 | smp_mb__after_atomic(); | |
954a73d5 | 1219 | |
bab7cfc7 | 1220 | flush_workqueue(kmpath_handlerd); |
2bded7bd | 1221 | multipath_wait_for_pg_init_completion(m); |
a044d016 | 1222 | flush_workqueue(kmultipathd); |
43829731 | 1223 | flush_work(&m->trigger_event); |
954a73d5 | 1224 | |
518257b1 MS |
1225 | clear_bit(MPATHF_PG_INIT_DISABLED, &m->flags); |
1226 | smp_mb__after_atomic(); | |
6df400ab KU |
1227 | } |
1228 | ||
1229 | static void multipath_dtr(struct dm_target *ti) | |
1230 | { | |
1231 | struct multipath *m = ti->private; | |
1232 | ||
2bded7bd | 1233 | flush_multipath_work(m); |
1da177e4 LT |
1234 | free_multipath(m); |
1235 | } | |
1236 | ||
1da177e4 LT |
1237 | /* |
1238 | * Take a path out of use. | |
1239 | */ | |
1240 | static int fail_path(struct pgpath *pgpath) | |
1241 | { | |
1242 | unsigned long flags; | |
1243 | struct multipath *m = pgpath->pg->m; | |
1244 | ||
1245 | spin_lock_irqsave(&m->lock, flags); | |
1246 | ||
6680073d | 1247 | if (!pgpath->is_active) |
1da177e4 LT |
1248 | goto out; |
1249 | ||
72d94861 | 1250 | DMWARN("Failing path %s.", pgpath->path.dev->name); |
1da177e4 LT |
1251 | |
1252 | pgpath->pg->ps.type->fail_path(&pgpath->pg->ps, &pgpath->path); | |
be7d31cc | 1253 | pgpath->is_active = false; |
1da177e4 LT |
1254 | pgpath->fail_count++; |
1255 | ||
91e968aa | 1256 | atomic_dec(&m->nr_valid_paths); |
1da177e4 LT |
1257 | |
1258 | if (pgpath == m->current_pgpath) | |
1259 | m->current_pgpath = NULL; | |
1260 | ||
b15546f9 | 1261 | dm_path_uevent(DM_UEVENT_PATH_FAILED, m->ti, |
91e968aa | 1262 | pgpath->path.dev->name, atomic_read(&m->nr_valid_paths)); |
b15546f9 | 1263 | |
fe9cf30e | 1264 | schedule_work(&m->trigger_event); |
1da177e4 LT |
1265 | |
1266 | out: | |
1267 | spin_unlock_irqrestore(&m->lock, flags); | |
1268 | ||
1269 | return 0; | |
1270 | } | |
1271 | ||
1272 | /* | |
1273 | * Reinstate a previously-failed path | |
1274 | */ | |
1275 | static int reinstate_path(struct pgpath *pgpath) | |
1276 | { | |
63d832c3 | 1277 | int r = 0, run_queue = 0; |
1da177e4 LT |
1278 | unsigned long flags; |
1279 | struct multipath *m = pgpath->pg->m; | |
91e968aa | 1280 | unsigned nr_valid_paths; |
1da177e4 LT |
1281 | |
1282 | spin_lock_irqsave(&m->lock, flags); | |
1283 | ||
6680073d | 1284 | if (pgpath->is_active) |
1da177e4 LT |
1285 | goto out; |
1286 | ||
ec31f3f7 | 1287 | DMWARN("Reinstating path %s.", pgpath->path.dev->name); |
1da177e4 LT |
1288 | |
1289 | r = pgpath->pg->ps.type->reinstate_path(&pgpath->pg->ps, &pgpath->path); | |
1290 | if (r) | |
1291 | goto out; | |
1292 | ||
be7d31cc | 1293 | pgpath->is_active = true; |
1da177e4 | 1294 | |
91e968aa MS |
1295 | nr_valid_paths = atomic_inc_return(&m->nr_valid_paths); |
1296 | if (nr_valid_paths == 1) { | |
e54f77dd | 1297 | m->current_pgpath = NULL; |
63d832c3 | 1298 | run_queue = 1; |
e54f77dd | 1299 | } else if (m->hw_handler_name && (m->current_pg == pgpath->pg)) { |
4e2d19e4 | 1300 | if (queue_work(kmpath_handlerd, &pgpath->activate_path.work)) |
91e968aa | 1301 | atomic_inc(&m->pg_init_in_progress); |
e54f77dd | 1302 | } |
1da177e4 | 1303 | |
b15546f9 | 1304 | dm_path_uevent(DM_UEVENT_PATH_REINSTATED, m->ti, |
91e968aa | 1305 | pgpath->path.dev->name, nr_valid_paths); |
b15546f9 | 1306 | |
fe9cf30e | 1307 | schedule_work(&m->trigger_event); |
1da177e4 LT |
1308 | |
1309 | out: | |
1310 | spin_unlock_irqrestore(&m->lock, flags); | |
76e33fe4 | 1311 | if (run_queue) { |
63d832c3 | 1312 | dm_table_run_md_queue_async(m->ti->table); |
7e48c768 | 1313 | process_queued_io_list(m); |
76e33fe4 | 1314 | } |
1da177e4 LT |
1315 | |
1316 | return r; | |
1317 | } | |
1318 | ||
1319 | /* | |
1320 | * Fail or reinstate all paths that match the provided struct dm_dev. | |
1321 | */ | |
1322 | static int action_dev(struct multipath *m, struct dm_dev *dev, | |
1323 | action_fn action) | |
1324 | { | |
19040c0b | 1325 | int r = -EINVAL; |
1da177e4 LT |
1326 | struct pgpath *pgpath; |
1327 | struct priority_group *pg; | |
1328 | ||
1329 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1330 | list_for_each_entry(pgpath, &pg->pgpaths, list) { | |
1331 | if (pgpath->path.dev == dev) | |
1332 | r = action(pgpath); | |
1333 | } | |
1334 | } | |
1335 | ||
1336 | return r; | |
1337 | } | |
1338 | ||
1339 | /* | |
1340 | * Temporarily try to avoid having to use the specified PG | |
1341 | */ | |
1342 | static void bypass_pg(struct multipath *m, struct priority_group *pg, | |
be7d31cc | 1343 | bool bypassed) |
1da177e4 LT |
1344 | { |
1345 | unsigned long flags; | |
1346 | ||
1347 | spin_lock_irqsave(&m->lock, flags); | |
1348 | ||
1349 | pg->bypassed = bypassed; | |
1350 | m->current_pgpath = NULL; | |
1351 | m->current_pg = NULL; | |
1352 | ||
1353 | spin_unlock_irqrestore(&m->lock, flags); | |
1354 | ||
fe9cf30e | 1355 | schedule_work(&m->trigger_event); |
1da177e4 LT |
1356 | } |
1357 | ||
1358 | /* | |
1359 | * Switch to using the specified PG from the next I/O that gets mapped | |
1360 | */ | |
1361 | static int switch_pg_num(struct multipath *m, const char *pgstr) | |
1362 | { | |
1363 | struct priority_group *pg; | |
1364 | unsigned pgnum; | |
1365 | unsigned long flags; | |
31998ef1 | 1366 | char dummy; |
1da177e4 | 1367 | |
31998ef1 | 1368 | if (!pgstr || (sscanf(pgstr, "%u%c", &pgnum, &dummy) != 1) || !pgnum || |
cc5bd925 | 1369 | !m->nr_priority_groups || (pgnum > m->nr_priority_groups)) { |
1da177e4 LT |
1370 | DMWARN("invalid PG number supplied to switch_pg_num"); |
1371 | return -EINVAL; | |
1372 | } | |
1373 | ||
1374 | spin_lock_irqsave(&m->lock, flags); | |
1375 | list_for_each_entry(pg, &m->priority_groups, list) { | |
be7d31cc | 1376 | pg->bypassed = false; |
1da177e4 LT |
1377 | if (--pgnum) |
1378 | continue; | |
1379 | ||
1380 | m->current_pgpath = NULL; | |
1381 | m->current_pg = NULL; | |
1382 | m->next_pg = pg; | |
1383 | } | |
1384 | spin_unlock_irqrestore(&m->lock, flags); | |
1385 | ||
fe9cf30e | 1386 | schedule_work(&m->trigger_event); |
1da177e4 LT |
1387 | return 0; |
1388 | } | |
1389 | ||
1390 | /* | |
1391 | * Set/clear bypassed status of a PG. | |
1392 | * PGs are numbered upwards from 1 in the order they were declared. | |
1393 | */ | |
be7d31cc | 1394 | static int bypass_pg_num(struct multipath *m, const char *pgstr, bool bypassed) |
1da177e4 LT |
1395 | { |
1396 | struct priority_group *pg; | |
1397 | unsigned pgnum; | |
31998ef1 | 1398 | char dummy; |
1da177e4 | 1399 | |
31998ef1 | 1400 | if (!pgstr || (sscanf(pgstr, "%u%c", &pgnum, &dummy) != 1) || !pgnum || |
cc5bd925 | 1401 | !m->nr_priority_groups || (pgnum > m->nr_priority_groups)) { |
1da177e4 LT |
1402 | DMWARN("invalid PG number supplied to bypass_pg"); |
1403 | return -EINVAL; | |
1404 | } | |
1405 | ||
1406 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1407 | if (!--pgnum) | |
1408 | break; | |
1409 | } | |
1410 | ||
1411 | bypass_pg(m, pg, bypassed); | |
1412 | return 0; | |
1413 | } | |
1414 | ||
c9e45581 DW |
1415 | /* |
1416 | * Should we retry pg_init immediately? | |
1417 | */ | |
be7d31cc | 1418 | static bool pg_init_limit_reached(struct multipath *m, struct pgpath *pgpath) |
c9e45581 DW |
1419 | { |
1420 | unsigned long flags; | |
be7d31cc | 1421 | bool limit_reached = false; |
c9e45581 DW |
1422 | |
1423 | spin_lock_irqsave(&m->lock, flags); | |
1424 | ||
91e968aa MS |
1425 | if (atomic_read(&m->pg_init_count) <= m->pg_init_retries && |
1426 | !test_bit(MPATHF_PG_INIT_DISABLED, &m->flags)) | |
518257b1 | 1427 | set_bit(MPATHF_PG_INIT_REQUIRED, &m->flags); |
c9e45581 | 1428 | else |
be7d31cc | 1429 | limit_reached = true; |
c9e45581 DW |
1430 | |
1431 | spin_unlock_irqrestore(&m->lock, flags); | |
1432 | ||
1433 | return limit_reached; | |
1434 | } | |
1435 | ||
3ae31f6a | 1436 | static void pg_init_done(void *data, int errors) |
cfae5c9b | 1437 | { |
83c0d5d5 | 1438 | struct pgpath *pgpath = data; |
cfae5c9b CS |
1439 | struct priority_group *pg = pgpath->pg; |
1440 | struct multipath *m = pg->m; | |
1441 | unsigned long flags; | |
be7d31cc | 1442 | bool delay_retry = false; |
cfae5c9b CS |
1443 | |
1444 | /* device or driver problems */ | |
1445 | switch (errors) { | |
1446 | case SCSI_DH_OK: | |
1447 | break; | |
1448 | case SCSI_DH_NOSYS: | |
1449 | if (!m->hw_handler_name) { | |
1450 | errors = 0; | |
1451 | break; | |
1452 | } | |
f7b934c8 MB |
1453 | DMERR("Could not failover the device: Handler scsi_dh_%s " |
1454 | "Error %d.", m->hw_handler_name, errors); | |
cfae5c9b CS |
1455 | /* |
1456 | * Fail path for now, so we do not ping pong | |
1457 | */ | |
1458 | fail_path(pgpath); | |
1459 | break; | |
1460 | case SCSI_DH_DEV_TEMP_BUSY: | |
1461 | /* | |
1462 | * Probably doing something like FW upgrade on the | |
1463 | * controller so try the other pg. | |
1464 | */ | |
be7d31cc | 1465 | bypass_pg(m, pg, true); |
cfae5c9b | 1466 | break; |
cfae5c9b | 1467 | case SCSI_DH_RETRY: |
4e2d19e4 CS |
1468 | /* Wait before retrying. */ |
1469 | delay_retry = 1; | |
cfae5c9b CS |
1470 | case SCSI_DH_IMM_RETRY: |
1471 | case SCSI_DH_RES_TEMP_UNAVAIL: | |
1472 | if (pg_init_limit_reached(m, pgpath)) | |
1473 | fail_path(pgpath); | |
1474 | errors = 0; | |
1475 | break; | |
ec31f3f7 | 1476 | case SCSI_DH_DEV_OFFLINED: |
cfae5c9b CS |
1477 | default: |
1478 | /* | |
1479 | * We probably do not want to fail the path for a device | |
1480 | * error, but this is what the old dm did. In future | |
1481 | * patches we can do more advanced handling. | |
1482 | */ | |
1483 | fail_path(pgpath); | |
1484 | } | |
1485 | ||
1486 | spin_lock_irqsave(&m->lock, flags); | |
1487 | if (errors) { | |
e54f77dd CS |
1488 | if (pgpath == m->current_pgpath) { |
1489 | DMERR("Could not failover device. Error %d.", errors); | |
1490 | m->current_pgpath = NULL; | |
1491 | m->current_pg = NULL; | |
1492 | } | |
518257b1 | 1493 | } else if (!test_bit(MPATHF_PG_INIT_REQUIRED, &m->flags)) |
be7d31cc | 1494 | pg->bypassed = false; |
cfae5c9b | 1495 | |
91e968aa | 1496 | if (atomic_dec_return(&m->pg_init_in_progress) > 0) |
d0259bf0 KU |
1497 | /* Activations of other paths are still on going */ |
1498 | goto out; | |
1499 | ||
518257b1 MS |
1500 | if (test_bit(MPATHF_PG_INIT_REQUIRED, &m->flags)) { |
1501 | if (delay_retry) | |
1502 | set_bit(MPATHF_PG_INIT_DELAY_RETRY, &m->flags); | |
1503 | else | |
1504 | clear_bit(MPATHF_PG_INIT_DELAY_RETRY, &m->flags); | |
1505 | ||
3e9f1be1 HR |
1506 | if (__pg_init_all_paths(m)) |
1507 | goto out; | |
1508 | } | |
518257b1 | 1509 | clear_bit(MPATHF_QUEUE_IO, &m->flags); |
d0259bf0 | 1510 | |
7e48c768 | 1511 | process_queued_io_list(m); |
76e33fe4 | 1512 | |
2bded7bd KU |
1513 | /* |
1514 | * Wake up any thread waiting to suspend. | |
1515 | */ | |
1516 | wake_up(&m->pg_init_wait); | |
1517 | ||
d0259bf0 | 1518 | out: |
cfae5c9b CS |
1519 | spin_unlock_irqrestore(&m->lock, flags); |
1520 | } | |
1521 | ||
bab7cfc7 CS |
1522 | static void activate_path(struct work_struct *work) |
1523 | { | |
e54f77dd | 1524 | struct pgpath *pgpath = |
4e2d19e4 | 1525 | container_of(work, struct pgpath, activate_path.work); |
f10e06b7 | 1526 | struct request_queue *q = bdev_get_queue(pgpath->path.dev->bdev); |
bab7cfc7 | 1527 | |
f10e06b7 MS |
1528 | if (pgpath->is_active && !blk_queue_dying(q)) |
1529 | scsi_dh_activate(q, pg_init_done, pgpath); | |
3a017509 HR |
1530 | else |
1531 | pg_init_done(pgpath, SCSI_DH_DEV_OFFLINED); | |
bab7cfc7 CS |
1532 | } |
1533 | ||
7e782af5 HR |
1534 | static int noretry_error(int error) |
1535 | { | |
1536 | switch (error) { | |
8ff232c1 HR |
1537 | case -EBADE: |
1538 | /* | |
1539 | * EBADE signals an reservation conflict. | |
1540 | * We shouldn't fail the path here as we can communicate with | |
1541 | * the target. We should failover to the next path, but in | |
1542 | * doing so we might be causing a ping-pong between paths. | |
1543 | * So just return the reservation conflict error. | |
1544 | */ | |
7e782af5 HR |
1545 | case -EOPNOTSUPP: |
1546 | case -EREMOTEIO: | |
1547 | case -EILSEQ: | |
1548 | case -ENODATA: | |
cc9d3c38 | 1549 | case -ENOSPC: |
7e782af5 HR |
1550 | return 1; |
1551 | } | |
1552 | ||
1553 | /* Anything else could be a path failure, so should be retried */ | |
1554 | return 0; | |
1555 | } | |
1556 | ||
1da177e4 LT |
1557 | /* |
1558 | * end_io handling | |
1559 | */ | |
f40c67f0 | 1560 | static int do_end_io(struct multipath *m, struct request *clone, |
028867ac | 1561 | int error, struct dm_mpath_io *mpio) |
1da177e4 | 1562 | { |
f40c67f0 KU |
1563 | /* |
1564 | * We don't queue any clone request inside the multipath target | |
1565 | * during end I/O handling, since those clone requests don't have | |
1566 | * bio clones. If we queue them inside the multipath target, | |
1567 | * we need to make bio clones, that requires memory allocation. | |
4cc96131 | 1568 | * (See drivers/md/dm-rq.c:end_clone_bio() about why the clone requests |
f40c67f0 KU |
1569 | * don't have bio clones.) |
1570 | * Instead of queueing the clone request here, we queue the original | |
1571 | * request into dm core, which will remake a clone request and | |
1572 | * clone bios for it and resubmit it later. | |
1573 | */ | |
1574 | int r = DM_ENDIO_REQUEUE; | |
1da177e4 | 1575 | |
f40c67f0 | 1576 | if (!error && !clone->errors) |
1da177e4 LT |
1577 | return 0; /* I/O complete */ |
1578 | ||
7eee4ae2 | 1579 | if (noretry_error(error)) |
959eb4e5 MS |
1580 | return error; |
1581 | ||
cfae5c9b CS |
1582 | if (mpio->pgpath) |
1583 | fail_path(mpio->pgpath); | |
1da177e4 | 1584 | |
91e968aa | 1585 | if (!atomic_read(&m->nr_valid_paths)) { |
518257b1 | 1586 | if (!test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) { |
76e33fe4 | 1587 | if (!must_push_back_rq(m)) |
751b2a7d | 1588 | r = -EIO; |
751b2a7d HR |
1589 | } |
1590 | } | |
1da177e4 | 1591 | |
f40c67f0 | 1592 | return r; |
1da177e4 LT |
1593 | } |
1594 | ||
f40c67f0 | 1595 | static int multipath_end_io(struct dm_target *ti, struct request *clone, |
1da177e4 LT |
1596 | int error, union map_info *map_context) |
1597 | { | |
028867ac | 1598 | struct multipath *m = ti->private; |
2eff1924 | 1599 | struct dm_mpath_io *mpio = get_mpio(map_context); |
a71a261f | 1600 | struct pgpath *pgpath; |
1da177e4 LT |
1601 | struct path_selector *ps; |
1602 | int r; | |
1603 | ||
466891f9 JN |
1604 | BUG_ON(!mpio); |
1605 | ||
2eff1924 | 1606 | r = do_end_io(m, clone, error, mpio); |
a71a261f | 1607 | pgpath = mpio->pgpath; |
1da177e4 LT |
1608 | if (pgpath) { |
1609 | ps = &pgpath->pg->ps; | |
1610 | if (ps->type->end_io) | |
02ab823f | 1611 | ps->type->end_io(ps, &pgpath->path, mpio->nr_bytes); |
1da177e4 | 1612 | } |
2eff1924 | 1613 | clear_request_fn_mpio(m, map_context); |
1da177e4 LT |
1614 | |
1615 | return r; | |
1616 | } | |
1617 | ||
76e33fe4 MS |
1618 | static int do_end_io_bio(struct multipath *m, struct bio *clone, |
1619 | int error, struct dm_mpath_io *mpio) | |
1620 | { | |
1621 | unsigned long flags; | |
1622 | ||
1623 | if (!error) | |
1624 | return 0; /* I/O complete */ | |
1625 | ||
1626 | if (noretry_error(error)) | |
1627 | return error; | |
1628 | ||
1629 | if (mpio->pgpath) | |
1630 | fail_path(mpio->pgpath); | |
1631 | ||
1632 | if (!atomic_read(&m->nr_valid_paths)) { | |
1633 | if (!test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) { | |
1634 | if (!must_push_back_bio(m)) | |
1635 | return -EIO; | |
1636 | return DM_ENDIO_REQUEUE; | |
76e33fe4 MS |
1637 | } |
1638 | } | |
1639 | ||
1640 | /* Queue for the daemon to resubmit */ | |
bf661be1 | 1641 | dm_bio_restore(get_bio_details_from_bio(clone), clone); |
76e33fe4 MS |
1642 | |
1643 | spin_lock_irqsave(&m->lock, flags); | |
1644 | bio_list_add(&m->queued_bios, clone); | |
1645 | spin_unlock_irqrestore(&m->lock, flags); | |
1646 | if (!test_bit(MPATHF_QUEUE_IO, &m->flags)) | |
1647 | queue_work(kmultipathd, &m->process_queued_bios); | |
1648 | ||
1649 | return DM_ENDIO_INCOMPLETE; | |
1650 | } | |
1651 | ||
1652 | static int multipath_end_io_bio(struct dm_target *ti, struct bio *clone, int error) | |
1653 | { | |
1654 | struct multipath *m = ti->private; | |
1655 | struct dm_mpath_io *mpio = get_mpio_from_bio(clone); | |
1656 | struct pgpath *pgpath; | |
1657 | struct path_selector *ps; | |
1658 | int r; | |
1659 | ||
1660 | BUG_ON(!mpio); | |
1661 | ||
1662 | r = do_end_io_bio(m, clone, error, mpio); | |
1663 | pgpath = mpio->pgpath; | |
1664 | if (pgpath) { | |
1665 | ps = &pgpath->pg->ps; | |
1666 | if (ps->type->end_io) | |
1667 | ps->type->end_io(ps, &pgpath->path, mpio->nr_bytes); | |
1668 | } | |
1669 | ||
1670 | return r; | |
1671 | } | |
1672 | ||
1da177e4 LT |
1673 | /* |
1674 | * Suspend can't complete until all the I/O is processed so if | |
436d4108 AK |
1675 | * the last path fails we must error any remaining I/O. |
1676 | * Note that if the freeze_bdev fails while suspending, the | |
1677 | * queue_if_no_path state is lost - userspace should reset it. | |
1da177e4 LT |
1678 | */ |
1679 | static void multipath_presuspend(struct dm_target *ti) | |
1680 | { | |
7943bd6d | 1681 | struct multipath *m = ti->private; |
1da177e4 | 1682 | |
be7d31cc | 1683 | queue_if_no_path(m, false, true); |
1da177e4 LT |
1684 | } |
1685 | ||
6df400ab KU |
1686 | static void multipath_postsuspend(struct dm_target *ti) |
1687 | { | |
6380f26f MA |
1688 | struct multipath *m = ti->private; |
1689 | ||
1690 | mutex_lock(&m->work_mutex); | |
2bded7bd | 1691 | flush_multipath_work(m); |
6380f26f | 1692 | mutex_unlock(&m->work_mutex); |
6df400ab KU |
1693 | } |
1694 | ||
436d4108 AK |
1695 | /* |
1696 | * Restore the queue_if_no_path setting. | |
1697 | */ | |
1da177e4 LT |
1698 | static void multipath_resume(struct dm_target *ti) |
1699 | { | |
7943bd6d | 1700 | struct multipath *m = ti->private; |
1814f2e3 | 1701 | unsigned long flags; |
1da177e4 | 1702 | |
1814f2e3 | 1703 | spin_lock_irqsave(&m->lock, flags); |
518257b1 MS |
1704 | if (test_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &m->flags)) |
1705 | set_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags); | |
1706 | else | |
1707 | clear_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags); | |
1814f2e3 | 1708 | spin_unlock_irqrestore(&m->lock, flags); |
1da177e4 LT |
1709 | } |
1710 | ||
1711 | /* | |
1712 | * Info output has the following format: | |
1713 | * num_multipath_feature_args [multipath_feature_args]* | |
1714 | * num_handler_status_args [handler_status_args]* | |
1715 | * num_groups init_group_number | |
1716 | * [A|D|E num_ps_status_args [ps_status_args]* | |
1717 | * num_paths num_selector_args | |
1718 | * [path_dev A|F fail_count [selector_args]* ]+ ]+ | |
1719 | * | |
1720 | * Table output has the following format (identical to the constructor string): | |
1721 | * num_feature_args [features_args]* | |
1722 | * num_handler_args hw_handler [hw_handler_args]* | |
1723 | * num_groups init_group_number | |
1724 | * [priority selector-name num_ps_args [ps_args]* | |
1725 | * num_paths num_selector_args [path_dev [selector_args]* ]+ ]+ | |
1726 | */ | |
fd7c092e MP |
1727 | static void multipath_status(struct dm_target *ti, status_type_t type, |
1728 | unsigned status_flags, char *result, unsigned maxlen) | |
1da177e4 LT |
1729 | { |
1730 | int sz = 0; | |
1731 | unsigned long flags; | |
7943bd6d | 1732 | struct multipath *m = ti->private; |
1da177e4 LT |
1733 | struct priority_group *pg; |
1734 | struct pgpath *p; | |
1735 | unsigned pg_num; | |
1736 | char state; | |
1737 | ||
1738 | spin_lock_irqsave(&m->lock, flags); | |
1739 | ||
1740 | /* Features */ | |
1741 | if (type == STATUSTYPE_INFO) | |
91e968aa MS |
1742 | DMEMIT("2 %u %u ", test_bit(MPATHF_QUEUE_IO, &m->flags), |
1743 | atomic_read(&m->pg_init_count)); | |
c9e45581 | 1744 | else { |
518257b1 | 1745 | DMEMIT("%u ", test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags) + |
4e2d19e4 | 1746 | (m->pg_init_retries > 0) * 2 + |
a58a935d | 1747 | (m->pg_init_delay_msecs != DM_PG_INIT_DELAY_DEFAULT) * 2 + |
e83068a5 MS |
1748 | test_bit(MPATHF_RETAIN_ATTACHED_HW_HANDLER, &m->flags) + |
1749 | (m->queue_mode != DM_TYPE_REQUEST_BASED) * 2); | |
1750 | ||
518257b1 | 1751 | if (test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) |
c9e45581 DW |
1752 | DMEMIT("queue_if_no_path "); |
1753 | if (m->pg_init_retries) | |
1754 | DMEMIT("pg_init_retries %u ", m->pg_init_retries); | |
4e2d19e4 CS |
1755 | if (m->pg_init_delay_msecs != DM_PG_INIT_DELAY_DEFAULT) |
1756 | DMEMIT("pg_init_delay_msecs %u ", m->pg_init_delay_msecs); | |
518257b1 | 1757 | if (test_bit(MPATHF_RETAIN_ATTACHED_HW_HANDLER, &m->flags)) |
a58a935d | 1758 | DMEMIT("retain_attached_hw_handler "); |
e83068a5 MS |
1759 | if (m->queue_mode != DM_TYPE_REQUEST_BASED) { |
1760 | switch(m->queue_mode) { | |
1761 | case DM_TYPE_BIO_BASED: | |
1762 | DMEMIT("queue_mode bio "); | |
1763 | break; | |
1764 | case DM_TYPE_MQ_REQUEST_BASED: | |
1765 | DMEMIT("queue_mode mq "); | |
1766 | break; | |
1767 | } | |
1768 | } | |
c9e45581 | 1769 | } |
1da177e4 | 1770 | |
cfae5c9b | 1771 | if (!m->hw_handler_name || type == STATUSTYPE_INFO) |
1da177e4 LT |
1772 | DMEMIT("0 "); |
1773 | else | |
cfae5c9b | 1774 | DMEMIT("1 %s ", m->hw_handler_name); |
1da177e4 LT |
1775 | |
1776 | DMEMIT("%u ", m->nr_priority_groups); | |
1777 | ||
1778 | if (m->next_pg) | |
1779 | pg_num = m->next_pg->pg_num; | |
1780 | else if (m->current_pg) | |
1781 | pg_num = m->current_pg->pg_num; | |
1782 | else | |
a490a07a | 1783 | pg_num = (m->nr_priority_groups ? 1 : 0); |
1da177e4 LT |
1784 | |
1785 | DMEMIT("%u ", pg_num); | |
1786 | ||
1787 | switch (type) { | |
1788 | case STATUSTYPE_INFO: | |
1789 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1790 | if (pg->bypassed) | |
1791 | state = 'D'; /* Disabled */ | |
1792 | else if (pg == m->current_pg) | |
1793 | state = 'A'; /* Currently Active */ | |
1794 | else | |
1795 | state = 'E'; /* Enabled */ | |
1796 | ||
1797 | DMEMIT("%c ", state); | |
1798 | ||
1799 | if (pg->ps.type->status) | |
1800 | sz += pg->ps.type->status(&pg->ps, NULL, type, | |
1801 | result + sz, | |
1802 | maxlen - sz); | |
1803 | else | |
1804 | DMEMIT("0 "); | |
1805 | ||
1806 | DMEMIT("%u %u ", pg->nr_pgpaths, | |
1807 | pg->ps.type->info_args); | |
1808 | ||
1809 | list_for_each_entry(p, &pg->pgpaths, list) { | |
1810 | DMEMIT("%s %s %u ", p->path.dev->name, | |
6680073d | 1811 | p->is_active ? "A" : "F", |
1da177e4 LT |
1812 | p->fail_count); |
1813 | if (pg->ps.type->status) | |
1814 | sz += pg->ps.type->status(&pg->ps, | |
1815 | &p->path, type, result + sz, | |
1816 | maxlen - sz); | |
1817 | } | |
1818 | } | |
1819 | break; | |
1820 | ||
1821 | case STATUSTYPE_TABLE: | |
1822 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1823 | DMEMIT("%s ", pg->ps.type->name); | |
1824 | ||
1825 | if (pg->ps.type->status) | |
1826 | sz += pg->ps.type->status(&pg->ps, NULL, type, | |
1827 | result + sz, | |
1828 | maxlen - sz); | |
1829 | else | |
1830 | DMEMIT("0 "); | |
1831 | ||
1832 | DMEMIT("%u %u ", pg->nr_pgpaths, | |
1833 | pg->ps.type->table_args); | |
1834 | ||
1835 | list_for_each_entry(p, &pg->pgpaths, list) { | |
1836 | DMEMIT("%s ", p->path.dev->name); | |
1837 | if (pg->ps.type->status) | |
1838 | sz += pg->ps.type->status(&pg->ps, | |
1839 | &p->path, type, result + sz, | |
1840 | maxlen - sz); | |
1841 | } | |
1842 | } | |
1843 | break; | |
1844 | } | |
1845 | ||
1846 | spin_unlock_irqrestore(&m->lock, flags); | |
1da177e4 LT |
1847 | } |
1848 | ||
1849 | static int multipath_message(struct dm_target *ti, unsigned argc, char **argv) | |
1850 | { | |
6380f26f | 1851 | int r = -EINVAL; |
1da177e4 | 1852 | struct dm_dev *dev; |
7943bd6d | 1853 | struct multipath *m = ti->private; |
1da177e4 LT |
1854 | action_fn action; |
1855 | ||
6380f26f MA |
1856 | mutex_lock(&m->work_mutex); |
1857 | ||
c2f3d24b KU |
1858 | if (dm_suspended(ti)) { |
1859 | r = -EBUSY; | |
1860 | goto out; | |
1861 | } | |
1862 | ||
1da177e4 | 1863 | if (argc == 1) { |
498f0103 | 1864 | if (!strcasecmp(argv[0], "queue_if_no_path")) { |
be7d31cc | 1865 | r = queue_if_no_path(m, true, false); |
6380f26f | 1866 | goto out; |
498f0103 | 1867 | } else if (!strcasecmp(argv[0], "fail_if_no_path")) { |
be7d31cc | 1868 | r = queue_if_no_path(m, false, false); |
6380f26f MA |
1869 | goto out; |
1870 | } | |
1da177e4 LT |
1871 | } |
1872 | ||
6380f26f | 1873 | if (argc != 2) { |
a356e426 | 1874 | DMWARN("Invalid multipath message arguments. Expected 2 arguments, got %d.", argc); |
6380f26f MA |
1875 | goto out; |
1876 | } | |
1da177e4 | 1877 | |
498f0103 | 1878 | if (!strcasecmp(argv[0], "disable_group")) { |
be7d31cc | 1879 | r = bypass_pg_num(m, argv[1], true); |
6380f26f | 1880 | goto out; |
498f0103 | 1881 | } else if (!strcasecmp(argv[0], "enable_group")) { |
be7d31cc | 1882 | r = bypass_pg_num(m, argv[1], false); |
6380f26f | 1883 | goto out; |
498f0103 | 1884 | } else if (!strcasecmp(argv[0], "switch_group")) { |
6380f26f MA |
1885 | r = switch_pg_num(m, argv[1]); |
1886 | goto out; | |
498f0103 | 1887 | } else if (!strcasecmp(argv[0], "reinstate_path")) |
1da177e4 | 1888 | action = reinstate_path; |
498f0103 | 1889 | else if (!strcasecmp(argv[0], "fail_path")) |
1da177e4 | 1890 | action = fail_path; |
6380f26f | 1891 | else { |
a356e426 | 1892 | DMWARN("Unrecognised multipath message received: %s", argv[0]); |
6380f26f MA |
1893 | goto out; |
1894 | } | |
1da177e4 | 1895 | |
8215d6ec | 1896 | r = dm_get_device(ti, argv[1], dm_table_get_mode(ti->table), &dev); |
1da177e4 | 1897 | if (r) { |
72d94861 | 1898 | DMWARN("message: error getting device %s", |
1da177e4 | 1899 | argv[1]); |
6380f26f | 1900 | goto out; |
1da177e4 LT |
1901 | } |
1902 | ||
1903 | r = action_dev(m, dev, action); | |
1904 | ||
1905 | dm_put_device(ti, dev); | |
1906 | ||
6380f26f MA |
1907 | out: |
1908 | mutex_unlock(&m->work_mutex); | |
1da177e4 | 1909 | return r; |
1da177e4 LT |
1910 | } |
1911 | ||
e56f81e0 CH |
1912 | static int multipath_prepare_ioctl(struct dm_target *ti, |
1913 | struct block_device **bdev, fmode_t *mode) | |
9af4aa30 | 1914 | { |
35991652 | 1915 | struct multipath *m = ti->private; |
2da1610a | 1916 | struct pgpath *current_pgpath; |
35991652 MP |
1917 | int r; |
1918 | ||
2da1610a MS |
1919 | current_pgpath = lockless_dereference(m->current_pgpath); |
1920 | if (!current_pgpath) | |
1921 | current_pgpath = choose_pgpath(m, 0); | |
9af4aa30 | 1922 | |
2da1610a | 1923 | if (current_pgpath) { |
518257b1 | 1924 | if (!test_bit(MPATHF_QUEUE_IO, &m->flags)) { |
2da1610a MS |
1925 | *bdev = current_pgpath->path.dev->bdev; |
1926 | *mode = current_pgpath->path.dev->mode; | |
43e43c9e JN |
1927 | r = 0; |
1928 | } else { | |
1929 | /* pg_init has not started or completed */ | |
1930 | r = -ENOTCONN; | |
1931 | } | |
1932 | } else { | |
1933 | /* No path is available */ | |
518257b1 | 1934 | if (test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) |
43e43c9e JN |
1935 | r = -ENOTCONN; |
1936 | else | |
1937 | r = -EIO; | |
e90dae1f | 1938 | } |
9af4aa30 | 1939 | |
5bbbfdf6 | 1940 | if (r == -ENOTCONN) { |
2da1610a | 1941 | if (!lockless_dereference(m->current_pg)) { |
3e9f1be1 | 1942 | /* Path status changed, redo selection */ |
2da1610a | 1943 | (void) choose_pgpath(m, 0); |
3e9f1be1 | 1944 | } |
518257b1 | 1945 | if (test_bit(MPATHF_PG_INIT_REQUIRED, &m->flags)) |
2da1610a | 1946 | pg_init_all_paths(m); |
63d832c3 | 1947 | dm_table_run_md_queue_async(m->ti->table); |
7e48c768 | 1948 | process_queued_io_list(m); |
3e9f1be1 | 1949 | } |
35991652 | 1950 | |
e56f81e0 CH |
1951 | /* |
1952 | * Only pass ioctls through if the device sizes match exactly. | |
1953 | */ | |
1954 | if (!r && ti->len != i_size_read((*bdev)->bd_inode) >> SECTOR_SHIFT) | |
1955 | return 1; | |
1956 | return r; | |
9af4aa30 MB |
1957 | } |
1958 | ||
af4874e0 MS |
1959 | static int multipath_iterate_devices(struct dm_target *ti, |
1960 | iterate_devices_callout_fn fn, void *data) | |
1961 | { | |
1962 | struct multipath *m = ti->private; | |
1963 | struct priority_group *pg; | |
1964 | struct pgpath *p; | |
1965 | int ret = 0; | |
1966 | ||
1967 | list_for_each_entry(pg, &m->priority_groups, list) { | |
1968 | list_for_each_entry(p, &pg->pgpaths, list) { | |
5dea271b | 1969 | ret = fn(ti, p->path.dev, ti->begin, ti->len, data); |
af4874e0 MS |
1970 | if (ret) |
1971 | goto out; | |
1972 | } | |
1973 | } | |
1974 | ||
1975 | out: | |
1976 | return ret; | |
1977 | } | |
1978 | ||
9f54cec5 | 1979 | static int pgpath_busy(struct pgpath *pgpath) |
f40c67f0 KU |
1980 | { |
1981 | struct request_queue *q = bdev_get_queue(pgpath->path.dev->bdev); | |
1982 | ||
52b09914 | 1983 | return blk_lld_busy(q); |
f40c67f0 KU |
1984 | } |
1985 | ||
1986 | /* | |
1987 | * We return "busy", only when we can map I/Os but underlying devices | |
1988 | * are busy (so even if we map I/Os now, the I/Os will wait on | |
1989 | * the underlying queue). | |
1990 | * In other words, if we want to kill I/Os or queue them inside us | |
1991 | * due to map unavailability, we don't return "busy". Otherwise, | |
1992 | * dm core won't give us the I/Os and we can't do what we want. | |
1993 | */ | |
1994 | static int multipath_busy(struct dm_target *ti) | |
1995 | { | |
be7d31cc | 1996 | bool busy = false, has_active = false; |
f40c67f0 | 1997 | struct multipath *m = ti->private; |
2da1610a | 1998 | struct priority_group *pg, *next_pg; |
f40c67f0 | 1999 | struct pgpath *pgpath; |
f40c67f0 | 2000 | |
b88efd43 MS |
2001 | /* pg_init in progress */ |
2002 | if (atomic_read(&m->pg_init_in_progress)) | |
2da1610a MS |
2003 | return true; |
2004 | ||
b88efd43 MS |
2005 | /* no paths available, for blk-mq: rely on IO mapping to delay requeue */ |
2006 | if (!atomic_read(&m->nr_valid_paths) && test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) | |
2007 | return (m->queue_mode != DM_TYPE_MQ_REQUEST_BASED); | |
2008 | ||
f40c67f0 | 2009 | /* Guess which priority_group will be used at next mapping time */ |
2da1610a MS |
2010 | pg = lockless_dereference(m->current_pg); |
2011 | next_pg = lockless_dereference(m->next_pg); | |
2012 | if (unlikely(!lockless_dereference(m->current_pgpath) && next_pg)) | |
2013 | pg = next_pg; | |
2014 | ||
2015 | if (!pg) { | |
f40c67f0 KU |
2016 | /* |
2017 | * We don't know which pg will be used at next mapping time. | |
2da1610a | 2018 | * We don't call choose_pgpath() here to avoid to trigger |
f40c67f0 KU |
2019 | * pg_init just by busy checking. |
2020 | * So we don't know whether underlying devices we will be using | |
2021 | * at next mapping time are busy or not. Just try mapping. | |
2022 | */ | |
2da1610a MS |
2023 | return busy; |
2024 | } | |
f40c67f0 KU |
2025 | |
2026 | /* | |
2027 | * If there is one non-busy active path at least, the path selector | |
2028 | * will be able to select it. So we consider such a pg as not busy. | |
2029 | */ | |
be7d31cc | 2030 | busy = true; |
2da1610a | 2031 | list_for_each_entry(pgpath, &pg->pgpaths, list) { |
f40c67f0 | 2032 | if (pgpath->is_active) { |
be7d31cc | 2033 | has_active = true; |
9f54cec5 | 2034 | if (!pgpath_busy(pgpath)) { |
be7d31cc | 2035 | busy = false; |
f40c67f0 KU |
2036 | break; |
2037 | } | |
2038 | } | |
2da1610a | 2039 | } |
f40c67f0 | 2040 | |
2da1610a | 2041 | if (!has_active) { |
f40c67f0 KU |
2042 | /* |
2043 | * No active path in this pg, so this pg won't be used and | |
2044 | * the current_pg will be changed at next mapping time. | |
2045 | * We need to try mapping to determine it. | |
2046 | */ | |
be7d31cc | 2047 | busy = false; |
2da1610a | 2048 | } |
f40c67f0 KU |
2049 | |
2050 | return busy; | |
2051 | } | |
2052 | ||
1da177e4 LT |
2053 | /*----------------------------------------------------------------- |
2054 | * Module setup | |
2055 | *---------------------------------------------------------------*/ | |
2056 | static struct target_type multipath_target = { | |
2057 | .name = "multipath", | |
e83068a5 | 2058 | .version = {1, 12, 0}, |
16f12266 | 2059 | .features = DM_TARGET_SINGLETON | DM_TARGET_IMMUTABLE, |
1da177e4 LT |
2060 | .module = THIS_MODULE, |
2061 | .ctr = multipath_ctr, | |
2062 | .dtr = multipath_dtr, | |
f40c67f0 | 2063 | .map_rq = multipath_map, |
e5863d9a MS |
2064 | .clone_and_map_rq = multipath_clone_and_map, |
2065 | .release_clone_rq = multipath_release_clone, | |
f40c67f0 | 2066 | .rq_end_io = multipath_end_io, |
76e33fe4 MS |
2067 | .map = multipath_map_bio, |
2068 | .end_io = multipath_end_io_bio, | |
2069 | .presuspend = multipath_presuspend, | |
2070 | .postsuspend = multipath_postsuspend, | |
2071 | .resume = multipath_resume, | |
2072 | .status = multipath_status, | |
2073 | .message = multipath_message, | |
2074 | .prepare_ioctl = multipath_prepare_ioctl, | |
2075 | .iterate_devices = multipath_iterate_devices, | |
2076 | .busy = multipath_busy, | |
2077 | }; | |
2078 | ||
1da177e4 LT |
2079 | static int __init dm_multipath_init(void) |
2080 | { | |
2081 | int r; | |
2082 | ||
76e33fe4 | 2083 | /* allocate a slab for the dm_mpath_ios */ |
028867ac | 2084 | _mpio_cache = KMEM_CACHE(dm_mpath_io, 0); |
1da177e4 LT |
2085 | if (!_mpio_cache) |
2086 | return -ENOMEM; | |
2087 | ||
2088 | r = dm_register_target(&multipath_target); | |
2089 | if (r < 0) { | |
76e33fe4 | 2090 | DMERR("request-based register failed %d", r); |
ff658e9c JT |
2091 | r = -EINVAL; |
2092 | goto bad_register_target; | |
1da177e4 LT |
2093 | } |
2094 | ||
4d4d66ab | 2095 | kmultipathd = alloc_workqueue("kmpathd", WQ_MEM_RECLAIM, 0); |
c557308e | 2096 | if (!kmultipathd) { |
0cd33124 | 2097 | DMERR("failed to create workqueue kmpathd"); |
ff658e9c JT |
2098 | r = -ENOMEM; |
2099 | goto bad_alloc_kmultipathd; | |
c557308e AK |
2100 | } |
2101 | ||
bab7cfc7 CS |
2102 | /* |
2103 | * A separate workqueue is used to handle the device handlers | |
2104 | * to avoid overloading existing workqueue. Overloading the | |
2105 | * old workqueue would also create a bottleneck in the | |
2106 | * path of the storage hardware device activation. | |
2107 | */ | |
4d4d66ab TH |
2108 | kmpath_handlerd = alloc_ordered_workqueue("kmpath_handlerd", |
2109 | WQ_MEM_RECLAIM); | |
bab7cfc7 CS |
2110 | if (!kmpath_handlerd) { |
2111 | DMERR("failed to create workqueue kmpath_handlerd"); | |
ff658e9c JT |
2112 | r = -ENOMEM; |
2113 | goto bad_alloc_kmpath_handlerd; | |
bab7cfc7 CS |
2114 | } |
2115 | ||
ff658e9c JT |
2116 | return 0; |
2117 | ||
2118 | bad_alloc_kmpath_handlerd: | |
2119 | destroy_workqueue(kmultipathd); | |
2120 | bad_alloc_kmultipathd: | |
2121 | dm_unregister_target(&multipath_target); | |
2122 | bad_register_target: | |
2123 | kmem_cache_destroy(_mpio_cache); | |
2124 | ||
1da177e4 LT |
2125 | return r; |
2126 | } | |
2127 | ||
2128 | static void __exit dm_multipath_exit(void) | |
2129 | { | |
bab7cfc7 | 2130 | destroy_workqueue(kmpath_handlerd); |
c557308e AK |
2131 | destroy_workqueue(kmultipathd); |
2132 | ||
10d3bd09 | 2133 | dm_unregister_target(&multipath_target); |
1da177e4 LT |
2134 | kmem_cache_destroy(_mpio_cache); |
2135 | } | |
2136 | ||
1da177e4 LT |
2137 | module_init(dm_multipath_init); |
2138 | module_exit(dm_multipath_exit); | |
2139 | ||
2140 | MODULE_DESCRIPTION(DM_NAME " multipath target"); | |
2141 | MODULE_AUTHOR("Sistina Software <dm-devel@redhat.com>"); | |
2142 | MODULE_LICENSE("GPL"); |