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1da177e4 LT |
1 | /* |
2 | * Copyright (C) 2001, 2002 Sistina Software (UK) Limited. | |
3 | * Copyright (C) 2004 Red Hat, Inc. All rights reserved. | |
4 | * | |
5 | * This file is released under the GPL. | |
6 | */ | |
7 | ||
8 | #include "dm.h" | |
9 | #include "dm-bio-list.h" | |
10 | ||
11 | #include <linux/init.h> | |
12 | #include <linux/module.h> | |
13 | #include <linux/moduleparam.h> | |
14 | #include <linux/blkpg.h> | |
15 | #include <linux/bio.h> | |
16 | #include <linux/buffer_head.h> | |
17 | #include <linux/mempool.h> | |
18 | #include <linux/slab.h> | |
19 | #include <linux/idr.h> | |
20 | ||
21 | static const char *_name = DM_NAME; | |
22 | ||
23 | static unsigned int major = 0; | |
24 | static unsigned int _major = 0; | |
25 | ||
26 | /* | |
27 | * One of these is allocated per bio. | |
28 | */ | |
29 | struct dm_io { | |
30 | struct mapped_device *md; | |
31 | int error; | |
32 | struct bio *bio; | |
33 | atomic_t io_count; | |
3eaf840e | 34 | unsigned long start_time; |
1da177e4 LT |
35 | }; |
36 | ||
37 | /* | |
38 | * One of these is allocated per target within a bio. Hopefully | |
39 | * this will be simplified out one day. | |
40 | */ | |
41 | struct target_io { | |
42 | struct dm_io *io; | |
43 | struct dm_target *ti; | |
44 | union map_info info; | |
45 | }; | |
46 | ||
47 | union map_info *dm_get_mapinfo(struct bio *bio) | |
48 | { | |
49 | if (bio && bio->bi_private) | |
50 | return &((struct target_io *)bio->bi_private)->info; | |
51 | return NULL; | |
52 | } | |
53 | ||
54 | /* | |
55 | * Bits for the md->flags field. | |
56 | */ | |
57 | #define DMF_BLOCK_IO 0 | |
58 | #define DMF_SUSPENDED 1 | |
aa8d7c2f | 59 | #define DMF_FROZEN 2 |
1da177e4 LT |
60 | |
61 | struct mapped_device { | |
2ca3310e AK |
62 | struct rw_semaphore io_lock; |
63 | struct semaphore suspend_lock; | |
1da177e4 LT |
64 | rwlock_t map_lock; |
65 | atomic_t holders; | |
66 | ||
67 | unsigned long flags; | |
68 | ||
69 | request_queue_t *queue; | |
70 | struct gendisk *disk; | |
71 | ||
72 | void *interface_ptr; | |
73 | ||
74 | /* | |
75 | * A list of ios that arrived while we were suspended. | |
76 | */ | |
77 | atomic_t pending; | |
78 | wait_queue_head_t wait; | |
79 | struct bio_list deferred; | |
80 | ||
81 | /* | |
82 | * The current mapping. | |
83 | */ | |
84 | struct dm_table *map; | |
85 | ||
86 | /* | |
87 | * io objects are allocated from here. | |
88 | */ | |
89 | mempool_t *io_pool; | |
90 | mempool_t *tio_pool; | |
91 | ||
92 | /* | |
93 | * Event handling. | |
94 | */ | |
95 | atomic_t event_nr; | |
96 | wait_queue_head_t eventq; | |
97 | ||
98 | /* | |
99 | * freeze/thaw support require holding onto a super block | |
100 | */ | |
101 | struct super_block *frozen_sb; | |
e39e2e95 | 102 | struct block_device *suspended_bdev; |
1da177e4 LT |
103 | }; |
104 | ||
105 | #define MIN_IOS 256 | |
106 | static kmem_cache_t *_io_cache; | |
107 | static kmem_cache_t *_tio_cache; | |
108 | ||
109 | static struct bio_set *dm_set; | |
110 | ||
111 | static int __init local_init(void) | |
112 | { | |
113 | int r; | |
114 | ||
115 | dm_set = bioset_create(16, 16, 4); | |
116 | if (!dm_set) | |
117 | return -ENOMEM; | |
118 | ||
119 | /* allocate a slab for the dm_ios */ | |
120 | _io_cache = kmem_cache_create("dm_io", | |
121 | sizeof(struct dm_io), 0, 0, NULL, NULL); | |
122 | if (!_io_cache) | |
123 | return -ENOMEM; | |
124 | ||
125 | /* allocate a slab for the target ios */ | |
126 | _tio_cache = kmem_cache_create("dm_tio", sizeof(struct target_io), | |
127 | 0, 0, NULL, NULL); | |
128 | if (!_tio_cache) { | |
129 | kmem_cache_destroy(_io_cache); | |
130 | return -ENOMEM; | |
131 | } | |
132 | ||
133 | _major = major; | |
134 | r = register_blkdev(_major, _name); | |
135 | if (r < 0) { | |
136 | kmem_cache_destroy(_tio_cache); | |
137 | kmem_cache_destroy(_io_cache); | |
138 | return r; | |
139 | } | |
140 | ||
141 | if (!_major) | |
142 | _major = r; | |
143 | ||
144 | return 0; | |
145 | } | |
146 | ||
147 | static void local_exit(void) | |
148 | { | |
149 | kmem_cache_destroy(_tio_cache); | |
150 | kmem_cache_destroy(_io_cache); | |
151 | ||
152 | bioset_free(dm_set); | |
153 | ||
154 | if (unregister_blkdev(_major, _name) < 0) | |
155 | DMERR("devfs_unregister_blkdev failed"); | |
156 | ||
157 | _major = 0; | |
158 | ||
159 | DMINFO("cleaned up"); | |
160 | } | |
161 | ||
162 | int (*_inits[])(void) __initdata = { | |
163 | local_init, | |
164 | dm_target_init, | |
165 | dm_linear_init, | |
166 | dm_stripe_init, | |
167 | dm_interface_init, | |
168 | }; | |
169 | ||
170 | void (*_exits[])(void) = { | |
171 | local_exit, | |
172 | dm_target_exit, | |
173 | dm_linear_exit, | |
174 | dm_stripe_exit, | |
175 | dm_interface_exit, | |
176 | }; | |
177 | ||
178 | static int __init dm_init(void) | |
179 | { | |
180 | const int count = ARRAY_SIZE(_inits); | |
181 | ||
182 | int r, i; | |
183 | ||
184 | for (i = 0; i < count; i++) { | |
185 | r = _inits[i](); | |
186 | if (r) | |
187 | goto bad; | |
188 | } | |
189 | ||
190 | return 0; | |
191 | ||
192 | bad: | |
193 | while (i--) | |
194 | _exits[i](); | |
195 | ||
196 | return r; | |
197 | } | |
198 | ||
199 | static void __exit dm_exit(void) | |
200 | { | |
201 | int i = ARRAY_SIZE(_exits); | |
202 | ||
203 | while (i--) | |
204 | _exits[i](); | |
205 | } | |
206 | ||
207 | /* | |
208 | * Block device functions | |
209 | */ | |
210 | static int dm_blk_open(struct inode *inode, struct file *file) | |
211 | { | |
212 | struct mapped_device *md; | |
213 | ||
214 | md = inode->i_bdev->bd_disk->private_data; | |
215 | dm_get(md); | |
216 | return 0; | |
217 | } | |
218 | ||
219 | static int dm_blk_close(struct inode *inode, struct file *file) | |
220 | { | |
221 | struct mapped_device *md; | |
222 | ||
223 | md = inode->i_bdev->bd_disk->private_data; | |
224 | dm_put(md); | |
225 | return 0; | |
226 | } | |
227 | ||
228 | static inline struct dm_io *alloc_io(struct mapped_device *md) | |
229 | { | |
230 | return mempool_alloc(md->io_pool, GFP_NOIO); | |
231 | } | |
232 | ||
233 | static inline void free_io(struct mapped_device *md, struct dm_io *io) | |
234 | { | |
235 | mempool_free(io, md->io_pool); | |
236 | } | |
237 | ||
238 | static inline struct target_io *alloc_tio(struct mapped_device *md) | |
239 | { | |
240 | return mempool_alloc(md->tio_pool, GFP_NOIO); | |
241 | } | |
242 | ||
243 | static inline void free_tio(struct mapped_device *md, struct target_io *tio) | |
244 | { | |
245 | mempool_free(tio, md->tio_pool); | |
246 | } | |
247 | ||
3eaf840e JNN |
248 | static void start_io_acct(struct dm_io *io) |
249 | { | |
250 | struct mapped_device *md = io->md; | |
251 | ||
252 | io->start_time = jiffies; | |
253 | ||
254 | preempt_disable(); | |
255 | disk_round_stats(dm_disk(md)); | |
256 | preempt_enable(); | |
257 | dm_disk(md)->in_flight = atomic_inc_return(&md->pending); | |
258 | } | |
259 | ||
260 | static int end_io_acct(struct dm_io *io) | |
261 | { | |
262 | struct mapped_device *md = io->md; | |
263 | struct bio *bio = io->bio; | |
264 | unsigned long duration = jiffies - io->start_time; | |
265 | int pending; | |
266 | int rw = bio_data_dir(bio); | |
267 | ||
268 | preempt_disable(); | |
269 | disk_round_stats(dm_disk(md)); | |
270 | preempt_enable(); | |
271 | dm_disk(md)->in_flight = pending = atomic_dec_return(&md->pending); | |
272 | ||
273 | disk_stat_add(dm_disk(md), ticks[rw], duration); | |
274 | ||
275 | return !pending; | |
276 | } | |
277 | ||
1da177e4 LT |
278 | /* |
279 | * Add the bio to the list of deferred io. | |
280 | */ | |
281 | static int queue_io(struct mapped_device *md, struct bio *bio) | |
282 | { | |
2ca3310e | 283 | down_write(&md->io_lock); |
1da177e4 LT |
284 | |
285 | if (!test_bit(DMF_BLOCK_IO, &md->flags)) { | |
2ca3310e | 286 | up_write(&md->io_lock); |
1da177e4 LT |
287 | return 1; |
288 | } | |
289 | ||
290 | bio_list_add(&md->deferred, bio); | |
291 | ||
2ca3310e | 292 | up_write(&md->io_lock); |
1da177e4 LT |
293 | return 0; /* deferred successfully */ |
294 | } | |
295 | ||
296 | /* | |
297 | * Everyone (including functions in this file), should use this | |
298 | * function to access the md->map field, and make sure they call | |
299 | * dm_table_put() when finished. | |
300 | */ | |
301 | struct dm_table *dm_get_table(struct mapped_device *md) | |
302 | { | |
303 | struct dm_table *t; | |
304 | ||
305 | read_lock(&md->map_lock); | |
306 | t = md->map; | |
307 | if (t) | |
308 | dm_table_get(t); | |
309 | read_unlock(&md->map_lock); | |
310 | ||
311 | return t; | |
312 | } | |
313 | ||
314 | /*----------------------------------------------------------------- | |
315 | * CRUD START: | |
316 | * A more elegant soln is in the works that uses the queue | |
317 | * merge fn, unfortunately there are a couple of changes to | |
318 | * the block layer that I want to make for this. So in the | |
319 | * interests of getting something for people to use I give | |
320 | * you this clearly demarcated crap. | |
321 | *---------------------------------------------------------------*/ | |
322 | ||
323 | /* | |
324 | * Decrements the number of outstanding ios that a bio has been | |
325 | * cloned into, completing the original io if necc. | |
326 | */ | |
858119e1 | 327 | static void dec_pending(struct dm_io *io, int error) |
1da177e4 LT |
328 | { |
329 | if (error) | |
330 | io->error = error; | |
331 | ||
332 | if (atomic_dec_and_test(&io->io_count)) { | |
3eaf840e | 333 | if (end_io_acct(io)) |
1da177e4 LT |
334 | /* nudge anyone waiting on suspend queue */ |
335 | wake_up(&io->md->wait); | |
336 | ||
337 | bio_endio(io->bio, io->bio->bi_size, io->error); | |
338 | free_io(io->md, io); | |
339 | } | |
340 | } | |
341 | ||
342 | static int clone_endio(struct bio *bio, unsigned int done, int error) | |
343 | { | |
344 | int r = 0; | |
345 | struct target_io *tio = bio->bi_private; | |
346 | struct dm_io *io = tio->io; | |
347 | dm_endio_fn endio = tio->ti->type->end_io; | |
348 | ||
349 | if (bio->bi_size) | |
350 | return 1; | |
351 | ||
352 | if (!bio_flagged(bio, BIO_UPTODATE) && !error) | |
353 | error = -EIO; | |
354 | ||
355 | if (endio) { | |
356 | r = endio(tio->ti, bio, error, &tio->info); | |
357 | if (r < 0) | |
358 | error = r; | |
359 | ||
360 | else if (r > 0) | |
361 | /* the target wants another shot at the io */ | |
362 | return 1; | |
363 | } | |
364 | ||
365 | free_tio(io->md, tio); | |
366 | dec_pending(io, error); | |
367 | bio_put(bio); | |
368 | return r; | |
369 | } | |
370 | ||
371 | static sector_t max_io_len(struct mapped_device *md, | |
372 | sector_t sector, struct dm_target *ti) | |
373 | { | |
374 | sector_t offset = sector - ti->begin; | |
375 | sector_t len = ti->len - offset; | |
376 | ||
377 | /* | |
378 | * Does the target need to split even further ? | |
379 | */ | |
380 | if (ti->split_io) { | |
381 | sector_t boundary; | |
382 | boundary = ((offset + ti->split_io) & ~(ti->split_io - 1)) | |
383 | - offset; | |
384 | if (len > boundary) | |
385 | len = boundary; | |
386 | } | |
387 | ||
388 | return len; | |
389 | } | |
390 | ||
391 | static void __map_bio(struct dm_target *ti, struct bio *clone, | |
392 | struct target_io *tio) | |
393 | { | |
394 | int r; | |
395 | ||
396 | /* | |
397 | * Sanity checks. | |
398 | */ | |
399 | BUG_ON(!clone->bi_size); | |
400 | ||
401 | clone->bi_end_io = clone_endio; | |
402 | clone->bi_private = tio; | |
403 | ||
404 | /* | |
405 | * Map the clone. If r == 0 we don't need to do | |
406 | * anything, the target has assumed ownership of | |
407 | * this io. | |
408 | */ | |
409 | atomic_inc(&tio->io->io_count); | |
410 | r = ti->type->map(ti, clone, &tio->info); | |
411 | if (r > 0) | |
412 | /* the bio has been remapped so dispatch it */ | |
413 | generic_make_request(clone); | |
414 | ||
415 | else if (r < 0) { | |
416 | /* error the io and bail out */ | |
417 | struct dm_io *io = tio->io; | |
418 | free_tio(tio->io->md, tio); | |
f6a80ea8 | 419 | dec_pending(io, r); |
1da177e4 LT |
420 | bio_put(clone); |
421 | } | |
422 | } | |
423 | ||
424 | struct clone_info { | |
425 | struct mapped_device *md; | |
426 | struct dm_table *map; | |
427 | struct bio *bio; | |
428 | struct dm_io *io; | |
429 | sector_t sector; | |
430 | sector_t sector_count; | |
431 | unsigned short idx; | |
432 | }; | |
433 | ||
3676347a PO |
434 | static void dm_bio_destructor(struct bio *bio) |
435 | { | |
436 | bio_free(bio, dm_set); | |
437 | } | |
438 | ||
1da177e4 LT |
439 | /* |
440 | * Creates a little bio that is just does part of a bvec. | |
441 | */ | |
442 | static struct bio *split_bvec(struct bio *bio, sector_t sector, | |
443 | unsigned short idx, unsigned int offset, | |
444 | unsigned int len) | |
445 | { | |
446 | struct bio *clone; | |
447 | struct bio_vec *bv = bio->bi_io_vec + idx; | |
448 | ||
449 | clone = bio_alloc_bioset(GFP_NOIO, 1, dm_set); | |
3676347a | 450 | clone->bi_destructor = dm_bio_destructor; |
1da177e4 LT |
451 | *clone->bi_io_vec = *bv; |
452 | ||
453 | clone->bi_sector = sector; | |
454 | clone->bi_bdev = bio->bi_bdev; | |
455 | clone->bi_rw = bio->bi_rw; | |
456 | clone->bi_vcnt = 1; | |
457 | clone->bi_size = to_bytes(len); | |
458 | clone->bi_io_vec->bv_offset = offset; | |
459 | clone->bi_io_vec->bv_len = clone->bi_size; | |
460 | ||
461 | return clone; | |
462 | } | |
463 | ||
464 | /* | |
465 | * Creates a bio that consists of range of complete bvecs. | |
466 | */ | |
467 | static struct bio *clone_bio(struct bio *bio, sector_t sector, | |
468 | unsigned short idx, unsigned short bv_count, | |
469 | unsigned int len) | |
470 | { | |
471 | struct bio *clone; | |
472 | ||
473 | clone = bio_clone(bio, GFP_NOIO); | |
474 | clone->bi_sector = sector; | |
475 | clone->bi_idx = idx; | |
476 | clone->bi_vcnt = idx + bv_count; | |
477 | clone->bi_size = to_bytes(len); | |
478 | clone->bi_flags &= ~(1 << BIO_SEG_VALID); | |
479 | ||
480 | return clone; | |
481 | } | |
482 | ||
483 | static void __clone_and_map(struct clone_info *ci) | |
484 | { | |
485 | struct bio *clone, *bio = ci->bio; | |
486 | struct dm_target *ti = dm_table_find_target(ci->map, ci->sector); | |
487 | sector_t len = 0, max = max_io_len(ci->md, ci->sector, ti); | |
488 | struct target_io *tio; | |
489 | ||
490 | /* | |
491 | * Allocate a target io object. | |
492 | */ | |
493 | tio = alloc_tio(ci->md); | |
494 | tio->io = ci->io; | |
495 | tio->ti = ti; | |
496 | memset(&tio->info, 0, sizeof(tio->info)); | |
497 | ||
498 | if (ci->sector_count <= max) { | |
499 | /* | |
500 | * Optimise for the simple case where we can do all of | |
501 | * the remaining io with a single clone. | |
502 | */ | |
503 | clone = clone_bio(bio, ci->sector, ci->idx, | |
504 | bio->bi_vcnt - ci->idx, ci->sector_count); | |
505 | __map_bio(ti, clone, tio); | |
506 | ci->sector_count = 0; | |
507 | ||
508 | } else if (to_sector(bio->bi_io_vec[ci->idx].bv_len) <= max) { | |
509 | /* | |
510 | * There are some bvecs that don't span targets. | |
511 | * Do as many of these as possible. | |
512 | */ | |
513 | int i; | |
514 | sector_t remaining = max; | |
515 | sector_t bv_len; | |
516 | ||
517 | for (i = ci->idx; remaining && (i < bio->bi_vcnt); i++) { | |
518 | bv_len = to_sector(bio->bi_io_vec[i].bv_len); | |
519 | ||
520 | if (bv_len > remaining) | |
521 | break; | |
522 | ||
523 | remaining -= bv_len; | |
524 | len += bv_len; | |
525 | } | |
526 | ||
527 | clone = clone_bio(bio, ci->sector, ci->idx, i - ci->idx, len); | |
528 | __map_bio(ti, clone, tio); | |
529 | ||
530 | ci->sector += len; | |
531 | ci->sector_count -= len; | |
532 | ci->idx = i; | |
533 | ||
534 | } else { | |
535 | /* | |
536 | * Create two copy bios to deal with io that has | |
537 | * been split across a target. | |
538 | */ | |
539 | struct bio_vec *bv = bio->bi_io_vec + ci->idx; | |
540 | ||
541 | clone = split_bvec(bio, ci->sector, ci->idx, | |
542 | bv->bv_offset, max); | |
543 | __map_bio(ti, clone, tio); | |
544 | ||
545 | ci->sector += max; | |
546 | ci->sector_count -= max; | |
547 | ti = dm_table_find_target(ci->map, ci->sector); | |
548 | ||
549 | len = to_sector(bv->bv_len) - max; | |
550 | clone = split_bvec(bio, ci->sector, ci->idx, | |
551 | bv->bv_offset + to_bytes(max), len); | |
552 | tio = alloc_tio(ci->md); | |
553 | tio->io = ci->io; | |
554 | tio->ti = ti; | |
555 | memset(&tio->info, 0, sizeof(tio->info)); | |
556 | __map_bio(ti, clone, tio); | |
557 | ||
558 | ci->sector += len; | |
559 | ci->sector_count -= len; | |
560 | ci->idx++; | |
561 | } | |
562 | } | |
563 | ||
564 | /* | |
565 | * Split the bio into several clones. | |
566 | */ | |
567 | static void __split_bio(struct mapped_device *md, struct bio *bio) | |
568 | { | |
569 | struct clone_info ci; | |
570 | ||
571 | ci.map = dm_get_table(md); | |
572 | if (!ci.map) { | |
573 | bio_io_error(bio, bio->bi_size); | |
574 | return; | |
575 | } | |
576 | ||
577 | ci.md = md; | |
578 | ci.bio = bio; | |
579 | ci.io = alloc_io(md); | |
580 | ci.io->error = 0; | |
581 | atomic_set(&ci.io->io_count, 1); | |
582 | ci.io->bio = bio; | |
583 | ci.io->md = md; | |
584 | ci.sector = bio->bi_sector; | |
585 | ci.sector_count = bio_sectors(bio); | |
586 | ci.idx = bio->bi_idx; | |
587 | ||
3eaf840e | 588 | start_io_acct(ci.io); |
1da177e4 LT |
589 | while (ci.sector_count) |
590 | __clone_and_map(&ci); | |
591 | ||
592 | /* drop the extra reference count */ | |
593 | dec_pending(ci.io, 0); | |
594 | dm_table_put(ci.map); | |
595 | } | |
596 | /*----------------------------------------------------------------- | |
597 | * CRUD END | |
598 | *---------------------------------------------------------------*/ | |
599 | ||
600 | /* | |
601 | * The request function that just remaps the bio built up by | |
602 | * dm_merge_bvec. | |
603 | */ | |
604 | static int dm_request(request_queue_t *q, struct bio *bio) | |
605 | { | |
606 | int r; | |
12f03a49 | 607 | int rw = bio_data_dir(bio); |
1da177e4 LT |
608 | struct mapped_device *md = q->queuedata; |
609 | ||
2ca3310e | 610 | down_read(&md->io_lock); |
1da177e4 | 611 | |
12f03a49 KC |
612 | disk_stat_inc(dm_disk(md), ios[rw]); |
613 | disk_stat_add(dm_disk(md), sectors[rw], bio_sectors(bio)); | |
614 | ||
1da177e4 LT |
615 | /* |
616 | * If we're suspended we have to queue | |
617 | * this io for later. | |
618 | */ | |
619 | while (test_bit(DMF_BLOCK_IO, &md->flags)) { | |
2ca3310e | 620 | up_read(&md->io_lock); |
1da177e4 LT |
621 | |
622 | if (bio_rw(bio) == READA) { | |
623 | bio_io_error(bio, bio->bi_size); | |
624 | return 0; | |
625 | } | |
626 | ||
627 | r = queue_io(md, bio); | |
628 | if (r < 0) { | |
629 | bio_io_error(bio, bio->bi_size); | |
630 | return 0; | |
631 | ||
632 | } else if (r == 0) | |
633 | return 0; /* deferred successfully */ | |
634 | ||
635 | /* | |
636 | * We're in a while loop, because someone could suspend | |
637 | * before we get to the following read lock. | |
638 | */ | |
2ca3310e | 639 | down_read(&md->io_lock); |
1da177e4 LT |
640 | } |
641 | ||
642 | __split_bio(md, bio); | |
2ca3310e | 643 | up_read(&md->io_lock); |
1da177e4 LT |
644 | return 0; |
645 | } | |
646 | ||
647 | static int dm_flush_all(request_queue_t *q, struct gendisk *disk, | |
648 | sector_t *error_sector) | |
649 | { | |
650 | struct mapped_device *md = q->queuedata; | |
651 | struct dm_table *map = dm_get_table(md); | |
652 | int ret = -ENXIO; | |
653 | ||
654 | if (map) { | |
cf222b37 | 655 | ret = dm_table_flush_all(map); |
1da177e4 LT |
656 | dm_table_put(map); |
657 | } | |
658 | ||
659 | return ret; | |
660 | } | |
661 | ||
662 | static void dm_unplug_all(request_queue_t *q) | |
663 | { | |
664 | struct mapped_device *md = q->queuedata; | |
665 | struct dm_table *map = dm_get_table(md); | |
666 | ||
667 | if (map) { | |
668 | dm_table_unplug_all(map); | |
669 | dm_table_put(map); | |
670 | } | |
671 | } | |
672 | ||
673 | static int dm_any_congested(void *congested_data, int bdi_bits) | |
674 | { | |
675 | int r; | |
676 | struct mapped_device *md = (struct mapped_device *) congested_data; | |
677 | struct dm_table *map = dm_get_table(md); | |
678 | ||
679 | if (!map || test_bit(DMF_BLOCK_IO, &md->flags)) | |
680 | r = bdi_bits; | |
681 | else | |
682 | r = dm_table_any_congested(map, bdi_bits); | |
683 | ||
684 | dm_table_put(map); | |
685 | return r; | |
686 | } | |
687 | ||
688 | /*----------------------------------------------------------------- | |
689 | * An IDR is used to keep track of allocated minor numbers. | |
690 | *---------------------------------------------------------------*/ | |
691 | static DECLARE_MUTEX(_minor_lock); | |
692 | static DEFINE_IDR(_minor_idr); | |
693 | ||
694 | static void free_minor(unsigned int minor) | |
695 | { | |
696 | down(&_minor_lock); | |
697 | idr_remove(&_minor_idr, minor); | |
698 | up(&_minor_lock); | |
699 | } | |
700 | ||
701 | /* | |
702 | * See if the device with a specific minor # is free. | |
703 | */ | |
704 | static int specific_minor(struct mapped_device *md, unsigned int minor) | |
705 | { | |
706 | int r, m; | |
707 | ||
708 | if (minor >= (1 << MINORBITS)) | |
709 | return -EINVAL; | |
710 | ||
711 | down(&_minor_lock); | |
712 | ||
713 | if (idr_find(&_minor_idr, minor)) { | |
714 | r = -EBUSY; | |
715 | goto out; | |
716 | } | |
717 | ||
718 | r = idr_pre_get(&_minor_idr, GFP_KERNEL); | |
719 | if (!r) { | |
720 | r = -ENOMEM; | |
721 | goto out; | |
722 | } | |
723 | ||
724 | r = idr_get_new_above(&_minor_idr, md, minor, &m); | |
725 | if (r) { | |
726 | goto out; | |
727 | } | |
728 | ||
729 | if (m != minor) { | |
730 | idr_remove(&_minor_idr, m); | |
731 | r = -EBUSY; | |
732 | goto out; | |
733 | } | |
734 | ||
735 | out: | |
736 | up(&_minor_lock); | |
737 | return r; | |
738 | } | |
739 | ||
740 | static int next_free_minor(struct mapped_device *md, unsigned int *minor) | |
741 | { | |
742 | int r; | |
743 | unsigned int m; | |
744 | ||
745 | down(&_minor_lock); | |
746 | ||
747 | r = idr_pre_get(&_minor_idr, GFP_KERNEL); | |
748 | if (!r) { | |
749 | r = -ENOMEM; | |
750 | goto out; | |
751 | } | |
752 | ||
753 | r = idr_get_new(&_minor_idr, md, &m); | |
754 | if (r) { | |
755 | goto out; | |
756 | } | |
757 | ||
758 | if (m >= (1 << MINORBITS)) { | |
759 | idr_remove(&_minor_idr, m); | |
760 | r = -ENOSPC; | |
761 | goto out; | |
762 | } | |
763 | ||
764 | *minor = m; | |
765 | ||
766 | out: | |
767 | up(&_minor_lock); | |
768 | return r; | |
769 | } | |
770 | ||
771 | static struct block_device_operations dm_blk_dops; | |
772 | ||
773 | /* | |
774 | * Allocate and initialise a blank device with a given minor. | |
775 | */ | |
776 | static struct mapped_device *alloc_dev(unsigned int minor, int persistent) | |
777 | { | |
778 | int r; | |
779 | struct mapped_device *md = kmalloc(sizeof(*md), GFP_KERNEL); | |
780 | ||
781 | if (!md) { | |
782 | DMWARN("unable to allocate device, out of memory."); | |
783 | return NULL; | |
784 | } | |
785 | ||
786 | /* get a minor number for the dev */ | |
787 | r = persistent ? specific_minor(md, minor) : next_free_minor(md, &minor); | |
788 | if (r < 0) | |
789 | goto bad1; | |
790 | ||
791 | memset(md, 0, sizeof(*md)); | |
2ca3310e AK |
792 | init_rwsem(&md->io_lock); |
793 | init_MUTEX(&md->suspend_lock); | |
1da177e4 LT |
794 | rwlock_init(&md->map_lock); |
795 | atomic_set(&md->holders, 1); | |
796 | atomic_set(&md->event_nr, 0); | |
797 | ||
798 | md->queue = blk_alloc_queue(GFP_KERNEL); | |
799 | if (!md->queue) | |
800 | goto bad1; | |
801 | ||
802 | md->queue->queuedata = md; | |
803 | md->queue->backing_dev_info.congested_fn = dm_any_congested; | |
804 | md->queue->backing_dev_info.congested_data = md; | |
805 | blk_queue_make_request(md->queue, dm_request); | |
daef265f | 806 | blk_queue_bounce_limit(md->queue, BLK_BOUNCE_ANY); |
1da177e4 LT |
807 | md->queue->unplug_fn = dm_unplug_all; |
808 | md->queue->issue_flush_fn = dm_flush_all; | |
809 | ||
810 | md->io_pool = mempool_create(MIN_IOS, mempool_alloc_slab, | |
811 | mempool_free_slab, _io_cache); | |
812 | if (!md->io_pool) | |
813 | goto bad2; | |
814 | ||
815 | md->tio_pool = mempool_create(MIN_IOS, mempool_alloc_slab, | |
816 | mempool_free_slab, _tio_cache); | |
817 | if (!md->tio_pool) | |
818 | goto bad3; | |
819 | ||
820 | md->disk = alloc_disk(1); | |
821 | if (!md->disk) | |
822 | goto bad4; | |
823 | ||
824 | md->disk->major = _major; | |
825 | md->disk->first_minor = minor; | |
826 | md->disk->fops = &dm_blk_dops; | |
827 | md->disk->queue = md->queue; | |
828 | md->disk->private_data = md; | |
829 | sprintf(md->disk->disk_name, "dm-%d", minor); | |
830 | add_disk(md->disk); | |
831 | ||
832 | atomic_set(&md->pending, 0); | |
833 | init_waitqueue_head(&md->wait); | |
834 | init_waitqueue_head(&md->eventq); | |
835 | ||
836 | return md; | |
837 | ||
838 | bad4: | |
839 | mempool_destroy(md->tio_pool); | |
840 | bad3: | |
841 | mempool_destroy(md->io_pool); | |
842 | bad2: | |
843 | blk_put_queue(md->queue); | |
844 | free_minor(minor); | |
845 | bad1: | |
846 | kfree(md); | |
847 | return NULL; | |
848 | } | |
849 | ||
850 | static void free_dev(struct mapped_device *md) | |
851 | { | |
63d94e48 JN |
852 | unsigned int minor = md->disk->first_minor; |
853 | ||
d9dde59b JN |
854 | if (md->suspended_bdev) { |
855 | thaw_bdev(md->suspended_bdev, NULL); | |
856 | bdput(md->suspended_bdev); | |
857 | } | |
1da177e4 LT |
858 | mempool_destroy(md->tio_pool); |
859 | mempool_destroy(md->io_pool); | |
860 | del_gendisk(md->disk); | |
63d94e48 | 861 | free_minor(minor); |
1da177e4 LT |
862 | put_disk(md->disk); |
863 | blk_put_queue(md->queue); | |
864 | kfree(md); | |
865 | } | |
866 | ||
867 | /* | |
868 | * Bind a table to the device. | |
869 | */ | |
870 | static void event_callback(void *context) | |
871 | { | |
872 | struct mapped_device *md = (struct mapped_device *) context; | |
873 | ||
874 | atomic_inc(&md->event_nr); | |
875 | wake_up(&md->eventq); | |
876 | } | |
877 | ||
4e90188b | 878 | static void __set_size(struct mapped_device *md, sector_t size) |
1da177e4 | 879 | { |
4e90188b | 880 | set_capacity(md->disk, size); |
1da177e4 | 881 | |
1b1dcc1b | 882 | mutex_lock(&md->suspended_bdev->bd_inode->i_mutex); |
e39e2e95 | 883 | i_size_write(md->suspended_bdev->bd_inode, (loff_t)size << SECTOR_SHIFT); |
1b1dcc1b | 884 | mutex_unlock(&md->suspended_bdev->bd_inode->i_mutex); |
1da177e4 LT |
885 | } |
886 | ||
887 | static int __bind(struct mapped_device *md, struct dm_table *t) | |
888 | { | |
889 | request_queue_t *q = md->queue; | |
890 | sector_t size; | |
891 | ||
892 | size = dm_table_get_size(t); | |
4e90188b | 893 | __set_size(md, size); |
1da177e4 LT |
894 | if (size == 0) |
895 | return 0; | |
896 | ||
2ca3310e AK |
897 | dm_table_get(t); |
898 | dm_table_event_callback(t, event_callback, md); | |
899 | ||
1da177e4 LT |
900 | write_lock(&md->map_lock); |
901 | md->map = t; | |
2ca3310e | 902 | dm_table_set_restrictions(t, q); |
1da177e4 LT |
903 | write_unlock(&md->map_lock); |
904 | ||
1da177e4 LT |
905 | return 0; |
906 | } | |
907 | ||
908 | static void __unbind(struct mapped_device *md) | |
909 | { | |
910 | struct dm_table *map = md->map; | |
911 | ||
912 | if (!map) | |
913 | return; | |
914 | ||
915 | dm_table_event_callback(map, NULL, NULL); | |
916 | write_lock(&md->map_lock); | |
917 | md->map = NULL; | |
918 | write_unlock(&md->map_lock); | |
919 | dm_table_put(map); | |
920 | } | |
921 | ||
922 | /* | |
923 | * Constructor for a new device. | |
924 | */ | |
925 | static int create_aux(unsigned int minor, int persistent, | |
926 | struct mapped_device **result) | |
927 | { | |
928 | struct mapped_device *md; | |
929 | ||
930 | md = alloc_dev(minor, persistent); | |
931 | if (!md) | |
932 | return -ENXIO; | |
933 | ||
934 | *result = md; | |
935 | return 0; | |
936 | } | |
937 | ||
938 | int dm_create(struct mapped_device **result) | |
939 | { | |
940 | return create_aux(0, 0, result); | |
941 | } | |
942 | ||
943 | int dm_create_with_minor(unsigned int minor, struct mapped_device **result) | |
944 | { | |
945 | return create_aux(minor, 1, result); | |
946 | } | |
947 | ||
637842cf | 948 | static struct mapped_device *dm_find_md(dev_t dev) |
1da177e4 LT |
949 | { |
950 | struct mapped_device *md; | |
1da177e4 LT |
951 | unsigned minor = MINOR(dev); |
952 | ||
953 | if (MAJOR(dev) != _major || minor >= (1 << MINORBITS)) | |
954 | return NULL; | |
955 | ||
956 | down(&_minor_lock); | |
957 | ||
958 | md = idr_find(&_minor_idr, minor); | |
637842cf DT |
959 | if (!md || (dm_disk(md)->first_minor != minor)) |
960 | md = NULL; | |
1da177e4 LT |
961 | |
962 | up(&_minor_lock); | |
963 | ||
637842cf DT |
964 | return md; |
965 | } | |
966 | ||
d229a958 DT |
967 | struct mapped_device *dm_get_md(dev_t dev) |
968 | { | |
969 | struct mapped_device *md = dm_find_md(dev); | |
970 | ||
971 | if (md) | |
972 | dm_get(md); | |
973 | ||
974 | return md; | |
975 | } | |
976 | ||
637842cf DT |
977 | void *dm_get_mdptr(dev_t dev) |
978 | { | |
979 | struct mapped_device *md; | |
980 | void *mdptr = NULL; | |
981 | ||
982 | md = dm_find_md(dev); | |
983 | if (md) | |
984 | mdptr = md->interface_ptr; | |
1da177e4 LT |
985 | return mdptr; |
986 | } | |
987 | ||
988 | void dm_set_mdptr(struct mapped_device *md, void *ptr) | |
989 | { | |
990 | md->interface_ptr = ptr; | |
991 | } | |
992 | ||
993 | void dm_get(struct mapped_device *md) | |
994 | { | |
995 | atomic_inc(&md->holders); | |
996 | } | |
997 | ||
998 | void dm_put(struct mapped_device *md) | |
999 | { | |
1000 | struct dm_table *map = dm_get_table(md); | |
1001 | ||
1002 | if (atomic_dec_and_test(&md->holders)) { | |
cf222b37 | 1003 | if (!dm_suspended(md)) { |
1da177e4 LT |
1004 | dm_table_presuspend_targets(map); |
1005 | dm_table_postsuspend_targets(map); | |
1006 | } | |
1007 | __unbind(md); | |
1008 | free_dev(md); | |
1009 | } | |
1010 | ||
1011 | dm_table_put(map); | |
1012 | } | |
1013 | ||
1014 | /* | |
1015 | * Process the deferred bios | |
1016 | */ | |
1017 | static void __flush_deferred_io(struct mapped_device *md, struct bio *c) | |
1018 | { | |
1019 | struct bio *n; | |
1020 | ||
1021 | while (c) { | |
1022 | n = c->bi_next; | |
1023 | c->bi_next = NULL; | |
1024 | __split_bio(md, c); | |
1025 | c = n; | |
1026 | } | |
1027 | } | |
1028 | ||
1029 | /* | |
1030 | * Swap in a new table (destroying old one). | |
1031 | */ | |
1032 | int dm_swap_table(struct mapped_device *md, struct dm_table *table) | |
1033 | { | |
93c534ae | 1034 | int r = -EINVAL; |
1da177e4 | 1035 | |
2ca3310e | 1036 | down(&md->suspend_lock); |
1da177e4 LT |
1037 | |
1038 | /* device must be suspended */ | |
cf222b37 | 1039 | if (!dm_suspended(md)) |
93c534ae | 1040 | goto out; |
1da177e4 LT |
1041 | |
1042 | __unbind(md); | |
1043 | r = __bind(md, table); | |
1da177e4 | 1044 | |
93c534ae | 1045 | out: |
2ca3310e | 1046 | up(&md->suspend_lock); |
93c534ae | 1047 | return r; |
1da177e4 LT |
1048 | } |
1049 | ||
1050 | /* | |
1051 | * Functions to lock and unlock any filesystem running on the | |
1052 | * device. | |
1053 | */ | |
2ca3310e | 1054 | static int lock_fs(struct mapped_device *md) |
1da177e4 | 1055 | { |
e39e2e95 | 1056 | int r; |
1da177e4 LT |
1057 | |
1058 | WARN_ON(md->frozen_sb); | |
dfbe03f6 | 1059 | |
e39e2e95 | 1060 | md->frozen_sb = freeze_bdev(md->suspended_bdev); |
dfbe03f6 | 1061 | if (IS_ERR(md->frozen_sb)) { |
cf222b37 | 1062 | r = PTR_ERR(md->frozen_sb); |
e39e2e95 AK |
1063 | md->frozen_sb = NULL; |
1064 | return r; | |
dfbe03f6 AK |
1065 | } |
1066 | ||
aa8d7c2f AK |
1067 | set_bit(DMF_FROZEN, &md->flags); |
1068 | ||
1da177e4 | 1069 | /* don't bdput right now, we don't want the bdev |
e39e2e95 | 1070 | * to go away while it is locked. |
1da177e4 LT |
1071 | */ |
1072 | return 0; | |
1073 | } | |
1074 | ||
2ca3310e | 1075 | static void unlock_fs(struct mapped_device *md) |
1da177e4 | 1076 | { |
aa8d7c2f AK |
1077 | if (!test_bit(DMF_FROZEN, &md->flags)) |
1078 | return; | |
1079 | ||
e39e2e95 | 1080 | thaw_bdev(md->suspended_bdev, md->frozen_sb); |
1da177e4 | 1081 | md->frozen_sb = NULL; |
aa8d7c2f | 1082 | clear_bit(DMF_FROZEN, &md->flags); |
1da177e4 LT |
1083 | } |
1084 | ||
1085 | /* | |
1086 | * We need to be able to change a mapping table under a mounted | |
1087 | * filesystem. For example we might want to move some data in | |
1088 | * the background. Before the table can be swapped with | |
1089 | * dm_bind_table, dm_suspend must be called to flush any in | |
1090 | * flight bios and ensure that any further io gets deferred. | |
1091 | */ | |
aa8d7c2f | 1092 | int dm_suspend(struct mapped_device *md, int do_lockfs) |
1da177e4 | 1093 | { |
2ca3310e | 1094 | struct dm_table *map = NULL; |
1da177e4 | 1095 | DECLARE_WAITQUEUE(wait, current); |
cf222b37 | 1096 | int r = -EINVAL; |
1da177e4 | 1097 | |
2ca3310e AK |
1098 | down(&md->suspend_lock); |
1099 | ||
1100 | if (dm_suspended(md)) | |
1101 | goto out; | |
1da177e4 LT |
1102 | |
1103 | map = dm_get_table(md); | |
1da177e4 | 1104 | |
cf222b37 AK |
1105 | /* This does not get reverted if there's an error later. */ |
1106 | dm_table_presuspend_targets(map); | |
1107 | ||
e39e2e95 AK |
1108 | md->suspended_bdev = bdget_disk(md->disk, 0); |
1109 | if (!md->suspended_bdev) { | |
1110 | DMWARN("bdget failed in dm_suspend"); | |
1111 | r = -ENOMEM; | |
1112 | goto out; | |
1113 | } | |
1114 | ||
cf222b37 | 1115 | /* Flush I/O to the device. */ |
aa8d7c2f AK |
1116 | if (do_lockfs) { |
1117 | r = lock_fs(md); | |
1118 | if (r) | |
1119 | goto out; | |
1120 | } | |
1da177e4 LT |
1121 | |
1122 | /* | |
354e0071 | 1123 | * First we set the BLOCK_IO flag so no more ios will be mapped. |
1da177e4 | 1124 | */ |
2ca3310e AK |
1125 | down_write(&md->io_lock); |
1126 | set_bit(DMF_BLOCK_IO, &md->flags); | |
1da177e4 | 1127 | |
1da177e4 | 1128 | add_wait_queue(&md->wait, &wait); |
2ca3310e | 1129 | up_write(&md->io_lock); |
1da177e4 LT |
1130 | |
1131 | /* unplug */ | |
2ca3310e | 1132 | if (map) |
1da177e4 | 1133 | dm_table_unplug_all(map); |
1da177e4 LT |
1134 | |
1135 | /* | |
1136 | * Then we wait for the already mapped ios to | |
1137 | * complete. | |
1138 | */ | |
1139 | while (1) { | |
1140 | set_current_state(TASK_INTERRUPTIBLE); | |
1141 | ||
1142 | if (!atomic_read(&md->pending) || signal_pending(current)) | |
1143 | break; | |
1144 | ||
1145 | io_schedule(); | |
1146 | } | |
1147 | set_current_state(TASK_RUNNING); | |
1148 | ||
2ca3310e | 1149 | down_write(&md->io_lock); |
1da177e4 LT |
1150 | remove_wait_queue(&md->wait, &wait); |
1151 | ||
1152 | /* were we interrupted ? */ | |
cf222b37 | 1153 | r = -EINTR; |
2ca3310e AK |
1154 | if (atomic_read(&md->pending)) { |
1155 | up_write(&md->io_lock); | |
1156 | unlock_fs(md); | |
1157 | clear_bit(DMF_BLOCK_IO, &md->flags); | |
1158 | goto out; | |
1159 | } | |
1160 | up_write(&md->io_lock); | |
1da177e4 | 1161 | |
cf222b37 | 1162 | dm_table_postsuspend_targets(map); |
1da177e4 | 1163 | |
2ca3310e | 1164 | set_bit(DMF_SUSPENDED, &md->flags); |
b84b0287 | 1165 | |
2ca3310e | 1166 | r = 0; |
b84b0287 | 1167 | |
2ca3310e | 1168 | out: |
e39e2e95 AK |
1169 | if (r && md->suspended_bdev) { |
1170 | bdput(md->suspended_bdev); | |
1171 | md->suspended_bdev = NULL; | |
1172 | } | |
1173 | ||
2ca3310e AK |
1174 | dm_table_put(map); |
1175 | up(&md->suspend_lock); | |
cf222b37 | 1176 | return r; |
1da177e4 LT |
1177 | } |
1178 | ||
1179 | int dm_resume(struct mapped_device *md) | |
1180 | { | |
cf222b37 | 1181 | int r = -EINVAL; |
1da177e4 | 1182 | struct bio *def; |
cf222b37 | 1183 | struct dm_table *map = NULL; |
1da177e4 | 1184 | |
2ca3310e AK |
1185 | down(&md->suspend_lock); |
1186 | if (!dm_suspended(md)) | |
cf222b37 | 1187 | goto out; |
cf222b37 AK |
1188 | |
1189 | map = dm_get_table(md); | |
2ca3310e | 1190 | if (!map || !dm_table_get_size(map)) |
cf222b37 | 1191 | goto out; |
1da177e4 LT |
1192 | |
1193 | dm_table_resume_targets(map); | |
2ca3310e AK |
1194 | |
1195 | down_write(&md->io_lock); | |
1da177e4 LT |
1196 | clear_bit(DMF_BLOCK_IO, &md->flags); |
1197 | ||
1198 | def = bio_list_get(&md->deferred); | |
1199 | __flush_deferred_io(md, def); | |
2ca3310e AK |
1200 | up_write(&md->io_lock); |
1201 | ||
1202 | unlock_fs(md); | |
1203 | ||
e39e2e95 AK |
1204 | bdput(md->suspended_bdev); |
1205 | md->suspended_bdev = NULL; | |
1206 | ||
2ca3310e AK |
1207 | clear_bit(DMF_SUSPENDED, &md->flags); |
1208 | ||
1da177e4 | 1209 | dm_table_unplug_all(map); |
1da177e4 | 1210 | |
cf222b37 | 1211 | r = 0; |
2ca3310e | 1212 | |
cf222b37 AK |
1213 | out: |
1214 | dm_table_put(map); | |
2ca3310e AK |
1215 | up(&md->suspend_lock); |
1216 | ||
cf222b37 | 1217 | return r; |
1da177e4 LT |
1218 | } |
1219 | ||
1220 | /*----------------------------------------------------------------- | |
1221 | * Event notification. | |
1222 | *---------------------------------------------------------------*/ | |
1223 | uint32_t dm_get_event_nr(struct mapped_device *md) | |
1224 | { | |
1225 | return atomic_read(&md->event_nr); | |
1226 | } | |
1227 | ||
1228 | int dm_wait_event(struct mapped_device *md, int event_nr) | |
1229 | { | |
1230 | return wait_event_interruptible(md->eventq, | |
1231 | (event_nr != atomic_read(&md->event_nr))); | |
1232 | } | |
1233 | ||
1234 | /* | |
1235 | * The gendisk is only valid as long as you have a reference | |
1236 | * count on 'md'. | |
1237 | */ | |
1238 | struct gendisk *dm_disk(struct mapped_device *md) | |
1239 | { | |
1240 | return md->disk; | |
1241 | } | |
1242 | ||
1243 | int dm_suspended(struct mapped_device *md) | |
1244 | { | |
1245 | return test_bit(DMF_SUSPENDED, &md->flags); | |
1246 | } | |
1247 | ||
1248 | static struct block_device_operations dm_blk_dops = { | |
1249 | .open = dm_blk_open, | |
1250 | .release = dm_blk_close, | |
1251 | .owner = THIS_MODULE | |
1252 | }; | |
1253 | ||
1254 | EXPORT_SYMBOL(dm_get_mapinfo); | |
1255 | ||
1256 | /* | |
1257 | * module hooks | |
1258 | */ | |
1259 | module_init(dm_init); | |
1260 | module_exit(dm_exit); | |
1261 | ||
1262 | module_param(major, uint, 0); | |
1263 | MODULE_PARM_DESC(major, "The major number of the device mapper"); | |
1264 | MODULE_DESCRIPTION(DM_NAME " driver"); | |
1265 | MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>"); | |
1266 | MODULE_LICENSE("GPL"); |