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