blob: fc335e09d0727b8d62e7679459acbe3248012d38 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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
21static const char *_name = DM_NAME;
22
23static unsigned int major = 0;
24static unsigned int _major = 0;
25
26/*
27 * One of these is allocated per bio.
28 */
29struct 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 */
40struct target_io {
41 struct dm_io *io;
42 struct dm_target *ti;
43 union map_info info;
44};
45
46union 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
Linus Torvalds1da177e2005-04-16 15:20:36 -070058
59struct mapped_device {
Alasdair G Kergon2ca33102005-07-28 21:16:00 -070060 struct rw_semaphore io_lock;
61 struct semaphore suspend_lock;
Linus Torvalds1da177e2005-04-16 15:20:36 -070062 rwlock_t map_lock;
63 atomic_t holders;
64
65 unsigned long flags;
66
67 request_queue_t *queue;
68 struct gendisk *disk;
69
70 void *interface_ptr;
71
72 /*
73 * A list of ios that arrived while we were suspended.
74 */
75 atomic_t pending;
76 wait_queue_head_t wait;
77 struct bio_list deferred;
78
79 /*
80 * The current mapping.
81 */
82 struct dm_table *map;
83
84 /*
85 * io objects are allocated from here.
86 */
87 mempool_t *io_pool;
88 mempool_t *tio_pool;
89
90 /*
91 * Event handling.
92 */
93 atomic_t event_nr;
94 wait_queue_head_t eventq;
95
96 /*
97 * freeze/thaw support require holding onto a super block
98 */
99 struct super_block *frozen_sb;
Alasdair G Kergone39e2e92006-01-06 00:20:05 -0800100 struct block_device *suspended_bdev;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101};
102
103#define MIN_IOS 256
104static kmem_cache_t *_io_cache;
105static kmem_cache_t *_tio_cache;
106
107static struct bio_set *dm_set;
108
109static int __init local_init(void)
110{
111 int r;
112
113 dm_set = bioset_create(16, 16, 4);
114 if (!dm_set)
115 return -ENOMEM;
116
117 /* allocate a slab for the dm_ios */
118 _io_cache = kmem_cache_create("dm_io",
119 sizeof(struct dm_io), 0, 0, NULL, NULL);
120 if (!_io_cache)
121 return -ENOMEM;
122
123 /* allocate a slab for the target ios */
124 _tio_cache = kmem_cache_create("dm_tio", sizeof(struct target_io),
125 0, 0, NULL, NULL);
126 if (!_tio_cache) {
127 kmem_cache_destroy(_io_cache);
128 return -ENOMEM;
129 }
130
131 _major = major;
132 r = register_blkdev(_major, _name);
133 if (r < 0) {
134 kmem_cache_destroy(_tio_cache);
135 kmem_cache_destroy(_io_cache);
136 return r;
137 }
138
139 if (!_major)
140 _major = r;
141
142 return 0;
143}
144
145static void local_exit(void)
146{
147 kmem_cache_destroy(_tio_cache);
148 kmem_cache_destroy(_io_cache);
149
150 bioset_free(dm_set);
151
152 if (unregister_blkdev(_major, _name) < 0)
153 DMERR("devfs_unregister_blkdev failed");
154
155 _major = 0;
156
157 DMINFO("cleaned up");
158}
159
160int (*_inits[])(void) __initdata = {
161 local_init,
162 dm_target_init,
163 dm_linear_init,
164 dm_stripe_init,
165 dm_interface_init,
166};
167
168void (*_exits[])(void) = {
169 local_exit,
170 dm_target_exit,
171 dm_linear_exit,
172 dm_stripe_exit,
173 dm_interface_exit,
174};
175
176static int __init dm_init(void)
177{
178 const int count = ARRAY_SIZE(_inits);
179
180 int r, i;
181
182 for (i = 0; i < count; i++) {
183 r = _inits[i]();
184 if (r)
185 goto bad;
186 }
187
188 return 0;
189
190 bad:
191 while (i--)
192 _exits[i]();
193
194 return r;
195}
196
197static void __exit dm_exit(void)
198{
199 int i = ARRAY_SIZE(_exits);
200
201 while (i--)
202 _exits[i]();
203}
204
205/*
206 * Block device functions
207 */
208static int dm_blk_open(struct inode *inode, struct file *file)
209{
210 struct mapped_device *md;
211
212 md = inode->i_bdev->bd_disk->private_data;
213 dm_get(md);
214 return 0;
215}
216
217static int dm_blk_close(struct inode *inode, struct file *file)
218{
219 struct mapped_device *md;
220
221 md = inode->i_bdev->bd_disk->private_data;
222 dm_put(md);
223 return 0;
224}
225
226static inline struct dm_io *alloc_io(struct mapped_device *md)
227{
228 return mempool_alloc(md->io_pool, GFP_NOIO);
229}
230
231static inline void free_io(struct mapped_device *md, struct dm_io *io)
232{
233 mempool_free(io, md->io_pool);
234}
235
236static inline struct target_io *alloc_tio(struct mapped_device *md)
237{
238 return mempool_alloc(md->tio_pool, GFP_NOIO);
239}
240
241static inline void free_tio(struct mapped_device *md, struct target_io *tio)
242{
243 mempool_free(tio, md->tio_pool);
244}
245
246/*
247 * Add the bio to the list of deferred io.
248 */
249static int queue_io(struct mapped_device *md, struct bio *bio)
250{
Alasdair G Kergon2ca33102005-07-28 21:16:00 -0700251 down_write(&md->io_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700252
253 if (!test_bit(DMF_BLOCK_IO, &md->flags)) {
Alasdair G Kergon2ca33102005-07-28 21:16:00 -0700254 up_write(&md->io_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700255 return 1;
256 }
257
258 bio_list_add(&md->deferred, bio);
259
Alasdair G Kergon2ca33102005-07-28 21:16:00 -0700260 up_write(&md->io_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700261 return 0; /* deferred successfully */
262}
263
264/*
265 * Everyone (including functions in this file), should use this
266 * function to access the md->map field, and make sure they call
267 * dm_table_put() when finished.
268 */
269struct dm_table *dm_get_table(struct mapped_device *md)
270{
271 struct dm_table *t;
272
273 read_lock(&md->map_lock);
274 t = md->map;
275 if (t)
276 dm_table_get(t);
277 read_unlock(&md->map_lock);
278
279 return t;
280}
281
282/*-----------------------------------------------------------------
283 * CRUD START:
284 * A more elegant soln is in the works that uses the queue
285 * merge fn, unfortunately there are a couple of changes to
286 * the block layer that I want to make for this. So in the
287 * interests of getting something for people to use I give
288 * you this clearly demarcated crap.
289 *---------------------------------------------------------------*/
290
291/*
292 * Decrements the number of outstanding ios that a bio has been
293 * cloned into, completing the original io if necc.
294 */
295static inline void dec_pending(struct dm_io *io, int error)
296{
297 if (error)
298 io->error = error;
299
300 if (atomic_dec_and_test(&io->io_count)) {
301 if (atomic_dec_and_test(&io->md->pending))
302 /* nudge anyone waiting on suspend queue */
303 wake_up(&io->md->wait);
304
305 bio_endio(io->bio, io->bio->bi_size, io->error);
306 free_io(io->md, io);
307 }
308}
309
310static int clone_endio(struct bio *bio, unsigned int done, int error)
311{
312 int r = 0;
313 struct target_io *tio = bio->bi_private;
314 struct dm_io *io = tio->io;
315 dm_endio_fn endio = tio->ti->type->end_io;
316
317 if (bio->bi_size)
318 return 1;
319
320 if (!bio_flagged(bio, BIO_UPTODATE) && !error)
321 error = -EIO;
322
323 if (endio) {
324 r = endio(tio->ti, bio, error, &tio->info);
325 if (r < 0)
326 error = r;
327
328 else if (r > 0)
329 /* the target wants another shot at the io */
330 return 1;
331 }
332
333 free_tio(io->md, tio);
334 dec_pending(io, error);
335 bio_put(bio);
336 return r;
337}
338
339static sector_t max_io_len(struct mapped_device *md,
340 sector_t sector, struct dm_target *ti)
341{
342 sector_t offset = sector - ti->begin;
343 sector_t len = ti->len - offset;
344
345 /*
346 * Does the target need to split even further ?
347 */
348 if (ti->split_io) {
349 sector_t boundary;
350 boundary = ((offset + ti->split_io) & ~(ti->split_io - 1))
351 - offset;
352 if (len > boundary)
353 len = boundary;
354 }
355
356 return len;
357}
358
359static void __map_bio(struct dm_target *ti, struct bio *clone,
360 struct target_io *tio)
361{
362 int r;
363
364 /*
365 * Sanity checks.
366 */
367 BUG_ON(!clone->bi_size);
368
369 clone->bi_end_io = clone_endio;
370 clone->bi_private = tio;
371
372 /*
373 * Map the clone. If r == 0 we don't need to do
374 * anything, the target has assumed ownership of
375 * this io.
376 */
377 atomic_inc(&tio->io->io_count);
378 r = ti->type->map(ti, clone, &tio->info);
379 if (r > 0)
380 /* the bio has been remapped so dispatch it */
381 generic_make_request(clone);
382
383 else if (r < 0) {
384 /* error the io and bail out */
385 struct dm_io *io = tio->io;
386 free_tio(tio->io->md, tio);
Alasdair G Kergonf6a80ea2005-07-12 15:53:01 -0700387 dec_pending(io, r);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700388 bio_put(clone);
389 }
390}
391
392struct clone_info {
393 struct mapped_device *md;
394 struct dm_table *map;
395 struct bio *bio;
396 struct dm_io *io;
397 sector_t sector;
398 sector_t sector_count;
399 unsigned short idx;
400};
401
Peter Osterlund36763472005-09-06 15:16:42 -0700402static void dm_bio_destructor(struct bio *bio)
403{
404 bio_free(bio, dm_set);
405}
406
Linus Torvalds1da177e2005-04-16 15:20:36 -0700407/*
408 * Creates a little bio that is just does part of a bvec.
409 */
410static struct bio *split_bvec(struct bio *bio, sector_t sector,
411 unsigned short idx, unsigned int offset,
412 unsigned int len)
413{
414 struct bio *clone;
415 struct bio_vec *bv = bio->bi_io_vec + idx;
416
417 clone = bio_alloc_bioset(GFP_NOIO, 1, dm_set);
Peter Osterlund36763472005-09-06 15:16:42 -0700418 clone->bi_destructor = dm_bio_destructor;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700419 *clone->bi_io_vec = *bv;
420
421 clone->bi_sector = sector;
422 clone->bi_bdev = bio->bi_bdev;
423 clone->bi_rw = bio->bi_rw;
424 clone->bi_vcnt = 1;
425 clone->bi_size = to_bytes(len);
426 clone->bi_io_vec->bv_offset = offset;
427 clone->bi_io_vec->bv_len = clone->bi_size;
428
429 return clone;
430}
431
432/*
433 * Creates a bio that consists of range of complete bvecs.
434 */
435static struct bio *clone_bio(struct bio *bio, sector_t sector,
436 unsigned short idx, unsigned short bv_count,
437 unsigned int len)
438{
439 struct bio *clone;
440
441 clone = bio_clone(bio, GFP_NOIO);
442 clone->bi_sector = sector;
443 clone->bi_idx = idx;
444 clone->bi_vcnt = idx + bv_count;
445 clone->bi_size = to_bytes(len);
446 clone->bi_flags &= ~(1 << BIO_SEG_VALID);
447
448 return clone;
449}
450
451static void __clone_and_map(struct clone_info *ci)
452{
453 struct bio *clone, *bio = ci->bio;
454 struct dm_target *ti = dm_table_find_target(ci->map, ci->sector);
455 sector_t len = 0, max = max_io_len(ci->md, ci->sector, ti);
456 struct target_io *tio;
457
458 /*
459 * Allocate a target io object.
460 */
461 tio = alloc_tio(ci->md);
462 tio->io = ci->io;
463 tio->ti = ti;
464 memset(&tio->info, 0, sizeof(tio->info));
465
466 if (ci->sector_count <= max) {
467 /*
468 * Optimise for the simple case where we can do all of
469 * the remaining io with a single clone.
470 */
471 clone = clone_bio(bio, ci->sector, ci->idx,
472 bio->bi_vcnt - ci->idx, ci->sector_count);
473 __map_bio(ti, clone, tio);
474 ci->sector_count = 0;
475
476 } else if (to_sector(bio->bi_io_vec[ci->idx].bv_len) <= max) {
477 /*
478 * There are some bvecs that don't span targets.
479 * Do as many of these as possible.
480 */
481 int i;
482 sector_t remaining = max;
483 sector_t bv_len;
484
485 for (i = ci->idx; remaining && (i < bio->bi_vcnt); i++) {
486 bv_len = to_sector(bio->bi_io_vec[i].bv_len);
487
488 if (bv_len > remaining)
489 break;
490
491 remaining -= bv_len;
492 len += bv_len;
493 }
494
495 clone = clone_bio(bio, ci->sector, ci->idx, i - ci->idx, len);
496 __map_bio(ti, clone, tio);
497
498 ci->sector += len;
499 ci->sector_count -= len;
500 ci->idx = i;
501
502 } else {
503 /*
504 * Create two copy bios to deal with io that has
505 * been split across a target.
506 */
507 struct bio_vec *bv = bio->bi_io_vec + ci->idx;
508
509 clone = split_bvec(bio, ci->sector, ci->idx,
510 bv->bv_offset, max);
511 __map_bio(ti, clone, tio);
512
513 ci->sector += max;
514 ci->sector_count -= max;
515 ti = dm_table_find_target(ci->map, ci->sector);
516
517 len = to_sector(bv->bv_len) - max;
518 clone = split_bvec(bio, ci->sector, ci->idx,
519 bv->bv_offset + to_bytes(max), len);
520 tio = alloc_tio(ci->md);
521 tio->io = ci->io;
522 tio->ti = ti;
523 memset(&tio->info, 0, sizeof(tio->info));
524 __map_bio(ti, clone, tio);
525
526 ci->sector += len;
527 ci->sector_count -= len;
528 ci->idx++;
529 }
530}
531
532/*
533 * Split the bio into several clones.
534 */
535static void __split_bio(struct mapped_device *md, struct bio *bio)
536{
537 struct clone_info ci;
538
539 ci.map = dm_get_table(md);
540 if (!ci.map) {
541 bio_io_error(bio, bio->bi_size);
542 return;
543 }
544
545 ci.md = md;
546 ci.bio = bio;
547 ci.io = alloc_io(md);
548 ci.io->error = 0;
549 atomic_set(&ci.io->io_count, 1);
550 ci.io->bio = bio;
551 ci.io->md = md;
552 ci.sector = bio->bi_sector;
553 ci.sector_count = bio_sectors(bio);
554 ci.idx = bio->bi_idx;
555
556 atomic_inc(&md->pending);
557 while (ci.sector_count)
558 __clone_and_map(&ci);
559
560 /* drop the extra reference count */
561 dec_pending(ci.io, 0);
562 dm_table_put(ci.map);
563}
564/*-----------------------------------------------------------------
565 * CRUD END
566 *---------------------------------------------------------------*/
567
568/*
569 * The request function that just remaps the bio built up by
570 * dm_merge_bvec.
571 */
572static int dm_request(request_queue_t *q, struct bio *bio)
573{
574 int r;
575 struct mapped_device *md = q->queuedata;
576
Alasdair G Kergon2ca33102005-07-28 21:16:00 -0700577 down_read(&md->io_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700578
579 /*
580 * If we're suspended we have to queue
581 * this io for later.
582 */
583 while (test_bit(DMF_BLOCK_IO, &md->flags)) {
Alasdair G Kergon2ca33102005-07-28 21:16:00 -0700584 up_read(&md->io_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700585
586 if (bio_rw(bio) == READA) {
587 bio_io_error(bio, bio->bi_size);
588 return 0;
589 }
590
591 r = queue_io(md, bio);
592 if (r < 0) {
593 bio_io_error(bio, bio->bi_size);
594 return 0;
595
596 } else if (r == 0)
597 return 0; /* deferred successfully */
598
599 /*
600 * We're in a while loop, because someone could suspend
601 * before we get to the following read lock.
602 */
Alasdair G Kergon2ca33102005-07-28 21:16:00 -0700603 down_read(&md->io_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700604 }
605
606 __split_bio(md, bio);
Alasdair G Kergon2ca33102005-07-28 21:16:00 -0700607 up_read(&md->io_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700608 return 0;
609}
610
611static int dm_flush_all(request_queue_t *q, struct gendisk *disk,
612 sector_t *error_sector)
613{
614 struct mapped_device *md = q->queuedata;
615 struct dm_table *map = dm_get_table(md);
616 int ret = -ENXIO;
617
618 if (map) {
Alasdair G Kergoncf222b32005-07-28 21:15:57 -0700619 ret = dm_table_flush_all(map);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700620 dm_table_put(map);
621 }
622
623 return ret;
624}
625
626static void dm_unplug_all(request_queue_t *q)
627{
628 struct mapped_device *md = q->queuedata;
629 struct dm_table *map = dm_get_table(md);
630
631 if (map) {
632 dm_table_unplug_all(map);
633 dm_table_put(map);
634 }
635}
636
637static int dm_any_congested(void *congested_data, int bdi_bits)
638{
639 int r;
640 struct mapped_device *md = (struct mapped_device *) congested_data;
641 struct dm_table *map = dm_get_table(md);
642
643 if (!map || test_bit(DMF_BLOCK_IO, &md->flags))
644 r = bdi_bits;
645 else
646 r = dm_table_any_congested(map, bdi_bits);
647
648 dm_table_put(map);
649 return r;
650}
651
652/*-----------------------------------------------------------------
653 * An IDR is used to keep track of allocated minor numbers.
654 *---------------------------------------------------------------*/
655static DECLARE_MUTEX(_minor_lock);
656static DEFINE_IDR(_minor_idr);
657
658static void free_minor(unsigned int minor)
659{
660 down(&_minor_lock);
661 idr_remove(&_minor_idr, minor);
662 up(&_minor_lock);
663}
664
665/*
666 * See if the device with a specific minor # is free.
667 */
668static int specific_minor(struct mapped_device *md, unsigned int minor)
669{
670 int r, m;
671
672 if (minor >= (1 << MINORBITS))
673 return -EINVAL;
674
675 down(&_minor_lock);
676
677 if (idr_find(&_minor_idr, minor)) {
678 r = -EBUSY;
679 goto out;
680 }
681
682 r = idr_pre_get(&_minor_idr, GFP_KERNEL);
683 if (!r) {
684 r = -ENOMEM;
685 goto out;
686 }
687
688 r = idr_get_new_above(&_minor_idr, md, minor, &m);
689 if (r) {
690 goto out;
691 }
692
693 if (m != minor) {
694 idr_remove(&_minor_idr, m);
695 r = -EBUSY;
696 goto out;
697 }
698
699out:
700 up(&_minor_lock);
701 return r;
702}
703
704static int next_free_minor(struct mapped_device *md, unsigned int *minor)
705{
706 int r;
707 unsigned int m;
708
709 down(&_minor_lock);
710
711 r = idr_pre_get(&_minor_idr, GFP_KERNEL);
712 if (!r) {
713 r = -ENOMEM;
714 goto out;
715 }
716
717 r = idr_get_new(&_minor_idr, md, &m);
718 if (r) {
719 goto out;
720 }
721
722 if (m >= (1 << MINORBITS)) {
723 idr_remove(&_minor_idr, m);
724 r = -ENOSPC;
725 goto out;
726 }
727
728 *minor = m;
729
730out:
731 up(&_minor_lock);
732 return r;
733}
734
735static struct block_device_operations dm_blk_dops;
736
737/*
738 * Allocate and initialise a blank device with a given minor.
739 */
740static struct mapped_device *alloc_dev(unsigned int minor, int persistent)
741{
742 int r;
743 struct mapped_device *md = kmalloc(sizeof(*md), GFP_KERNEL);
744
745 if (!md) {
746 DMWARN("unable to allocate device, out of memory.");
747 return NULL;
748 }
749
750 /* get a minor number for the dev */
751 r = persistent ? specific_minor(md, minor) : next_free_minor(md, &minor);
752 if (r < 0)
753 goto bad1;
754
755 memset(md, 0, sizeof(*md));
Alasdair G Kergon2ca33102005-07-28 21:16:00 -0700756 init_rwsem(&md->io_lock);
757 init_MUTEX(&md->suspend_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700758 rwlock_init(&md->map_lock);
759 atomic_set(&md->holders, 1);
760 atomic_set(&md->event_nr, 0);
761
762 md->queue = blk_alloc_queue(GFP_KERNEL);
763 if (!md->queue)
764 goto bad1;
765
766 md->queue->queuedata = md;
767 md->queue->backing_dev_info.congested_fn = dm_any_congested;
768 md->queue->backing_dev_info.congested_data = md;
769 blk_queue_make_request(md->queue, dm_request);
770 md->queue->unplug_fn = dm_unplug_all;
771 md->queue->issue_flush_fn = dm_flush_all;
772
773 md->io_pool = mempool_create(MIN_IOS, mempool_alloc_slab,
774 mempool_free_slab, _io_cache);
775 if (!md->io_pool)
776 goto bad2;
777
778 md->tio_pool = mempool_create(MIN_IOS, mempool_alloc_slab,
779 mempool_free_slab, _tio_cache);
780 if (!md->tio_pool)
781 goto bad3;
782
783 md->disk = alloc_disk(1);
784 if (!md->disk)
785 goto bad4;
786
787 md->disk->major = _major;
788 md->disk->first_minor = minor;
789 md->disk->fops = &dm_blk_dops;
790 md->disk->queue = md->queue;
791 md->disk->private_data = md;
792 sprintf(md->disk->disk_name, "dm-%d", minor);
793 add_disk(md->disk);
794
795 atomic_set(&md->pending, 0);
796 init_waitqueue_head(&md->wait);
797 init_waitqueue_head(&md->eventq);
798
799 return md;
800
801 bad4:
802 mempool_destroy(md->tio_pool);
803 bad3:
804 mempool_destroy(md->io_pool);
805 bad2:
806 blk_put_queue(md->queue);
807 free_minor(minor);
808 bad1:
809 kfree(md);
810 return NULL;
811}
812
813static void free_dev(struct mapped_device *md)
814{
815 free_minor(md->disk->first_minor);
816 mempool_destroy(md->tio_pool);
817 mempool_destroy(md->io_pool);
818 del_gendisk(md->disk);
819 put_disk(md->disk);
820 blk_put_queue(md->queue);
821 kfree(md);
822}
823
824/*
825 * Bind a table to the device.
826 */
827static void event_callback(void *context)
828{
829 struct mapped_device *md = (struct mapped_device *) context;
830
831 atomic_inc(&md->event_nr);
832 wake_up(&md->eventq);
833}
834
Alasdair G Kergon4e901882005-07-28 21:15:59 -0700835static void __set_size(struct mapped_device *md, sector_t size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700836{
Alasdair G Kergon4e901882005-07-28 21:15:59 -0700837 set_capacity(md->disk, size);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700838
Alasdair G Kergone39e2e92006-01-06 00:20:05 -0800839 down(&md->suspended_bdev->bd_inode->i_sem);
840 i_size_write(md->suspended_bdev->bd_inode, (loff_t)size << SECTOR_SHIFT);
841 up(&md->suspended_bdev->bd_inode->i_sem);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700842}
843
844static int __bind(struct mapped_device *md, struct dm_table *t)
845{
846 request_queue_t *q = md->queue;
847 sector_t size;
848
849 size = dm_table_get_size(t);
Alasdair G Kergon4e901882005-07-28 21:15:59 -0700850 __set_size(md, size);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700851 if (size == 0)
852 return 0;
853
Linus Torvalds1da177e2005-04-16 15:20:36 -0700854 dm_table_get(t);
Alasdair G Kergoncf222b32005-07-28 21:15:57 -0700855 dm_table_event_callback(t, event_callback, md);
Alasdair G Kergon2ca33102005-07-28 21:16:00 -0700856
857 write_lock(&md->map_lock);
858 md->map = t;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700859 dm_table_set_restrictions(t, q);
Alasdair G Kergon2ca33102005-07-28 21:16:00 -0700860 write_unlock(&md->map_lock);
861
Linus Torvalds1da177e2005-04-16 15:20:36 -0700862 return 0;
863}
864
865static void __unbind(struct mapped_device *md)
866{
867 struct dm_table *map = md->map;
868
869 if (!map)
870 return;
871
872 dm_table_event_callback(map, NULL, NULL);
873 write_lock(&md->map_lock);
874 md->map = NULL;
875 write_unlock(&md->map_lock);
876 dm_table_put(map);
877}
878
879/*
880 * Constructor for a new device.
881 */
882static int create_aux(unsigned int minor, int persistent,
883 struct mapped_device **result)
884{
885 struct mapped_device *md;
886
887 md = alloc_dev(minor, persistent);
888 if (!md)
889 return -ENXIO;
890
891 *result = md;
892 return 0;
893}
894
895int dm_create(struct mapped_device **result)
896{
897 return create_aux(0, 0, result);
898}
899
900int dm_create_with_minor(unsigned int minor, struct mapped_device **result)
901{
902 return create_aux(minor, 1, result);
903}
904
David Teigland637842c2006-01-06 00:20:00 -0800905static struct mapped_device *dm_find_md(dev_t dev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700906{
907 struct mapped_device *md;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700908 unsigned minor = MINOR(dev);
909
910 if (MAJOR(dev) != _major || minor >= (1 << MINORBITS))
911 return NULL;
912
913 down(&_minor_lock);
914
915 md = idr_find(&_minor_idr, minor);
David Teigland637842c2006-01-06 00:20:00 -0800916 if (!md || (dm_disk(md)->first_minor != minor))
917 md = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700918
919 up(&_minor_lock);
920
David Teigland637842c2006-01-06 00:20:00 -0800921 return md;
922}
923
David Teiglandd229a952006-01-06 00:20:01 -0800924struct mapped_device *dm_get_md(dev_t dev)
925{
926 struct mapped_device *md = dm_find_md(dev);
927
928 if (md)
929 dm_get(md);
930
931 return md;
932}
933
David Teigland637842c2006-01-06 00:20:00 -0800934void *dm_get_mdptr(dev_t dev)
935{
936 struct mapped_device *md;
937 void *mdptr = NULL;
938
939 md = dm_find_md(dev);
940 if (md)
941 mdptr = md->interface_ptr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700942 return mdptr;
943}
944
945void dm_set_mdptr(struct mapped_device *md, void *ptr)
946{
947 md->interface_ptr = ptr;
948}
949
950void dm_get(struct mapped_device *md)
951{
952 atomic_inc(&md->holders);
953}
954
955void dm_put(struct mapped_device *md)
956{
957 struct dm_table *map = dm_get_table(md);
958
959 if (atomic_dec_and_test(&md->holders)) {
Alasdair G Kergoncf222b32005-07-28 21:15:57 -0700960 if (!dm_suspended(md)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700961 dm_table_presuspend_targets(map);
962 dm_table_postsuspend_targets(map);
963 }
964 __unbind(md);
965 free_dev(md);
966 }
967
968 dm_table_put(map);
969}
970
971/*
972 * Process the deferred bios
973 */
974static void __flush_deferred_io(struct mapped_device *md, struct bio *c)
975{
976 struct bio *n;
977
978 while (c) {
979 n = c->bi_next;
980 c->bi_next = NULL;
981 __split_bio(md, c);
982 c = n;
983 }
984}
985
986/*
987 * Swap in a new table (destroying old one).
988 */
989int dm_swap_table(struct mapped_device *md, struct dm_table *table)
990{
Alasdair G Kergon93c534a2005-07-12 15:53:05 -0700991 int r = -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700992
Alasdair G Kergon2ca33102005-07-28 21:16:00 -0700993 down(&md->suspend_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700994
995 /* device must be suspended */
Alasdair G Kergoncf222b32005-07-28 21:15:57 -0700996 if (!dm_suspended(md))
Alasdair G Kergon93c534a2005-07-12 15:53:05 -0700997 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700998
999 __unbind(md);
1000 r = __bind(md, table);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001001
Alasdair G Kergon93c534a2005-07-12 15:53:05 -07001002out:
Alasdair G Kergon2ca33102005-07-28 21:16:00 -07001003 up(&md->suspend_lock);
Alasdair G Kergon93c534a2005-07-12 15:53:05 -07001004 return r;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001005}
1006
1007/*
1008 * Functions to lock and unlock any filesystem running on the
1009 * device.
1010 */
Alasdair G Kergon2ca33102005-07-28 21:16:00 -07001011static int lock_fs(struct mapped_device *md)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001012{
Alasdair G Kergone39e2e92006-01-06 00:20:05 -08001013 int r;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001014
1015 WARN_ON(md->frozen_sb);
Alasdair G Kergondfbe03f2005-05-05 16:16:04 -07001016
Alasdair G Kergone39e2e92006-01-06 00:20:05 -08001017 md->frozen_sb = freeze_bdev(md->suspended_bdev);
Alasdair G Kergondfbe03f2005-05-05 16:16:04 -07001018 if (IS_ERR(md->frozen_sb)) {
Alasdair G Kergoncf222b32005-07-28 21:15:57 -07001019 r = PTR_ERR(md->frozen_sb);
Alasdair G Kergone39e2e92006-01-06 00:20:05 -08001020 md->frozen_sb = NULL;
1021 return r;
Alasdair G Kergondfbe03f2005-05-05 16:16:04 -07001022 }
1023
Linus Torvalds1da177e2005-04-16 15:20:36 -07001024 /* don't bdput right now, we don't want the bdev
Alasdair G Kergone39e2e92006-01-06 00:20:05 -08001025 * to go away while it is locked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001026 */
1027 return 0;
1028}
1029
Alasdair G Kergon2ca33102005-07-28 21:16:00 -07001030static void unlock_fs(struct mapped_device *md)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001031{
Alasdair G Kergone39e2e92006-01-06 00:20:05 -08001032 thaw_bdev(md->suspended_bdev, md->frozen_sb);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001033 md->frozen_sb = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001034}
1035
1036/*
1037 * We need to be able to change a mapping table under a mounted
1038 * filesystem. For example we might want to move some data in
1039 * the background. Before the table can be swapped with
1040 * dm_bind_table, dm_suspend must be called to flush any in
1041 * flight bios and ensure that any further io gets deferred.
1042 */
1043int dm_suspend(struct mapped_device *md)
1044{
Alasdair G Kergon2ca33102005-07-28 21:16:00 -07001045 struct dm_table *map = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001046 DECLARE_WAITQUEUE(wait, current);
Alasdair G Kergoncf222b32005-07-28 21:15:57 -07001047 int r = -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001048
Alasdair G Kergon2ca33102005-07-28 21:16:00 -07001049 down(&md->suspend_lock);
1050
1051 if (dm_suspended(md))
1052 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001053
1054 map = dm_get_table(md);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001055
Alasdair G Kergoncf222b32005-07-28 21:15:57 -07001056 /* This does not get reverted if there's an error later. */
1057 dm_table_presuspend_targets(map);
1058
Alasdair G Kergone39e2e92006-01-06 00:20:05 -08001059 md->suspended_bdev = bdget_disk(md->disk, 0);
1060 if (!md->suspended_bdev) {
1061 DMWARN("bdget failed in dm_suspend");
1062 r = -ENOMEM;
1063 goto out;
1064 }
1065
Alasdair G Kergoncf222b32005-07-28 21:15:57 -07001066 /* Flush I/O to the device. */
Alasdair G Kergon2ca33102005-07-28 21:16:00 -07001067 r = lock_fs(md);
1068 if (r)
1069 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001070
1071 /*
Alasdair G Kergon354e0072005-05-05 16:16:05 -07001072 * First we set the BLOCK_IO flag so no more ios will be mapped.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001073 */
Alasdair G Kergon2ca33102005-07-28 21:16:00 -07001074 down_write(&md->io_lock);
1075 set_bit(DMF_BLOCK_IO, &md->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001076
Linus Torvalds1da177e2005-04-16 15:20:36 -07001077 add_wait_queue(&md->wait, &wait);
Alasdair G Kergon2ca33102005-07-28 21:16:00 -07001078 up_write(&md->io_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001079
1080 /* unplug */
Alasdair G Kergon2ca33102005-07-28 21:16:00 -07001081 if (map)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001082 dm_table_unplug_all(map);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001083
1084 /*
1085 * Then we wait for the already mapped ios to
1086 * complete.
1087 */
1088 while (1) {
1089 set_current_state(TASK_INTERRUPTIBLE);
1090
1091 if (!atomic_read(&md->pending) || signal_pending(current))
1092 break;
1093
1094 io_schedule();
1095 }
1096 set_current_state(TASK_RUNNING);
1097
Alasdair G Kergon2ca33102005-07-28 21:16:00 -07001098 down_write(&md->io_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001099 remove_wait_queue(&md->wait, &wait);
1100
1101 /* were we interrupted ? */
Alasdair G Kergoncf222b32005-07-28 21:15:57 -07001102 r = -EINTR;
Alasdair G Kergon2ca33102005-07-28 21:16:00 -07001103 if (atomic_read(&md->pending)) {
1104 up_write(&md->io_lock);
1105 unlock_fs(md);
1106 clear_bit(DMF_BLOCK_IO, &md->flags);
1107 goto out;
1108 }
1109 up_write(&md->io_lock);
1110
1111 dm_table_postsuspend_targets(map);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001112
1113 set_bit(DMF_SUSPENDED, &md->flags);
1114
Alasdair G Kergon2ca33102005-07-28 21:16:00 -07001115 r = 0;
1116
1117out:
Alasdair G Kergone39e2e92006-01-06 00:20:05 -08001118 if (r && md->suspended_bdev) {
1119 bdput(md->suspended_bdev);
1120 md->suspended_bdev = NULL;
1121 }
1122
Linus Torvalds1da177e2005-04-16 15:20:36 -07001123 dm_table_put(map);
Alasdair G Kergon2ca33102005-07-28 21:16:00 -07001124 up(&md->suspend_lock);
Alasdair G Kergoncf222b32005-07-28 21:15:57 -07001125 return r;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001126}
1127
1128int dm_resume(struct mapped_device *md)
1129{
Alasdair G Kergoncf222b32005-07-28 21:15:57 -07001130 int r = -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001131 struct bio *def;
Alasdair G Kergoncf222b32005-07-28 21:15:57 -07001132 struct dm_table *map = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001133
Alasdair G Kergon2ca33102005-07-28 21:16:00 -07001134 down(&md->suspend_lock);
1135 if (!dm_suspended(md))
Alasdair G Kergoncf222b32005-07-28 21:15:57 -07001136 goto out;
Alasdair G Kergoncf222b32005-07-28 21:15:57 -07001137
1138 map = dm_get_table(md);
Alasdair G Kergon2ca33102005-07-28 21:16:00 -07001139 if (!map || !dm_table_get_size(map))
Alasdair G Kergoncf222b32005-07-28 21:15:57 -07001140 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001141
1142 dm_table_resume_targets(map);
Alasdair G Kergon2ca33102005-07-28 21:16:00 -07001143
1144 down_write(&md->io_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001145 clear_bit(DMF_BLOCK_IO, &md->flags);
1146
1147 def = bio_list_get(&md->deferred);
1148 __flush_deferred_io(md, def);
Alasdair G Kergon2ca33102005-07-28 21:16:00 -07001149 up_write(&md->io_lock);
1150
1151 unlock_fs(md);
1152
Alasdair G Kergone39e2e92006-01-06 00:20:05 -08001153 bdput(md->suspended_bdev);
1154 md->suspended_bdev = NULL;
1155
Alasdair G Kergon2ca33102005-07-28 21:16:00 -07001156 clear_bit(DMF_SUSPENDED, &md->flags);
1157
Linus Torvalds1da177e2005-04-16 15:20:36 -07001158 dm_table_unplug_all(map);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001159
Alasdair G Kergoncf222b32005-07-28 21:15:57 -07001160 r = 0;
Alasdair G Kergon2ca33102005-07-28 21:16:00 -07001161
Alasdair G Kergoncf222b32005-07-28 21:15:57 -07001162out:
1163 dm_table_put(map);
Alasdair G Kergon2ca33102005-07-28 21:16:00 -07001164 up(&md->suspend_lock);
1165
Alasdair G Kergoncf222b32005-07-28 21:15:57 -07001166 return r;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001167}
1168
1169/*-----------------------------------------------------------------
1170 * Event notification.
1171 *---------------------------------------------------------------*/
1172uint32_t dm_get_event_nr(struct mapped_device *md)
1173{
1174 return atomic_read(&md->event_nr);
1175}
1176
1177int dm_wait_event(struct mapped_device *md, int event_nr)
1178{
1179 return wait_event_interruptible(md->eventq,
1180 (event_nr != atomic_read(&md->event_nr)));
1181}
1182
1183/*
1184 * The gendisk is only valid as long as you have a reference
1185 * count on 'md'.
1186 */
1187struct gendisk *dm_disk(struct mapped_device *md)
1188{
1189 return md->disk;
1190}
1191
1192int dm_suspended(struct mapped_device *md)
1193{
1194 return test_bit(DMF_SUSPENDED, &md->flags);
1195}
1196
1197static struct block_device_operations dm_blk_dops = {
1198 .open = dm_blk_open,
1199 .release = dm_blk_close,
1200 .owner = THIS_MODULE
1201};
1202
1203EXPORT_SYMBOL(dm_get_mapinfo);
1204
1205/*
1206 * module hooks
1207 */
1208module_init(dm_init);
1209module_exit(dm_exit);
1210
1211module_param(major, uint, 0);
1212MODULE_PARM_DESC(major, "The major number of the device mapper");
1213MODULE_DESCRIPTION(DM_NAME " driver");
1214MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
1215MODULE_LICENSE("GPL");