blob: 737d38865b693fb0288306477587f4e0d52f6cfa [file] [log] [blame]
Joe Thornber991d9fa2011-10-31 20:21:18 +00001/*
2 * Copyright (C) 2011 Red Hat, Inc.
3 *
4 * This file is released under the GPL.
5 */
6
7#include "dm-thin-metadata.h"
8#include "persistent-data/dm-btree.h"
9#include "persistent-data/dm-space-map.h"
10#include "persistent-data/dm-space-map-disk.h"
11#include "persistent-data/dm-transaction-manager.h"
12
13#include <linux/list.h>
14#include <linux/device-mapper.h>
15#include <linux/workqueue.h>
16
17/*--------------------------------------------------------------------------
18 * As far as the metadata goes, there is:
19 *
20 * - A superblock in block zero, taking up fewer than 512 bytes for
21 * atomic writes.
22 *
23 * - A space map managing the metadata blocks.
24 *
25 * - A space map managing the data blocks.
26 *
27 * - A btree mapping our internal thin dev ids onto struct disk_device_details.
28 *
29 * - A hierarchical btree, with 2 levels which effectively maps (thin
30 * dev id, virtual block) -> block_time. Block time is a 64-bit
31 * field holding the time in the low 24 bits, and block in the top 48
32 * bits.
33 *
34 * BTrees consist solely of btree_nodes, that fill a block. Some are
35 * internal nodes, as such their values are a __le64 pointing to other
36 * nodes. Leaf nodes can store data of any reasonable size (ie. much
37 * smaller than the block size). The nodes consist of the header,
38 * followed by an array of keys, followed by an array of values. We have
39 * to binary search on the keys so they're all held together to help the
40 * cpu cache.
41 *
42 * Space maps have 2 btrees:
43 *
44 * - One maps a uint64_t onto a struct index_entry. Which points to a
45 * bitmap block, and has some details about how many free entries there
46 * are etc.
47 *
48 * - The bitmap blocks have a header (for the checksum). Then the rest
49 * of the block is pairs of bits. With the meaning being:
50 *
51 * 0 - ref count is 0
52 * 1 - ref count is 1
53 * 2 - ref count is 2
54 * 3 - ref count is higher than 2
55 *
56 * - If the count is higher than 2 then the ref count is entered in a
57 * second btree that directly maps the block_address to a uint32_t ref
58 * count.
59 *
60 * The space map metadata variant doesn't have a bitmaps btree. Instead
61 * it has one single blocks worth of index_entries. This avoids
62 * recursive issues with the bitmap btree needing to allocate space in
63 * order to insert. With a small data block size such as 64k the
64 * metadata support data devices that are hundreds of terrabytes.
65 *
66 * The space maps allocate space linearly from front to back. Space that
67 * is freed in a transaction is never recycled within that transaction.
68 * To try and avoid fragmenting _free_ space the allocator always goes
69 * back and fills in gaps.
70 *
71 * All metadata io is in THIN_METADATA_BLOCK_SIZE sized/aligned chunks
72 * from the block manager.
73 *--------------------------------------------------------------------------*/
74
75#define DM_MSG_PREFIX "thin metadata"
76
77#define THIN_SUPERBLOCK_MAGIC 27022010
78#define THIN_SUPERBLOCK_LOCATION 0
79#define THIN_VERSION 1
80#define THIN_METADATA_CACHE_SIZE 64
81#define SECTOR_TO_BLOCK_SHIFT 3
82
83/* This should be plenty */
84#define SPACE_MAP_ROOT_SIZE 128
85
86/*
87 * Little endian on-disk superblock and device details.
88 */
89struct thin_disk_superblock {
90 __le32 csum; /* Checksum of superblock except for this field. */
91 __le32 flags;
92 __le64 blocknr; /* This block number, dm_block_t. */
93
94 __u8 uuid[16];
95 __le64 magic;
96 __le32 version;
97 __le32 time;
98
99 __le64 trans_id;
100
101 /*
102 * Root held by userspace transactions.
103 */
104 __le64 held_root;
105
106 __u8 data_space_map_root[SPACE_MAP_ROOT_SIZE];
107 __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
108
109 /*
110 * 2-level btree mapping (dev_id, (dev block, time)) -> data block
111 */
112 __le64 data_mapping_root;
113
114 /*
115 * Device detail root mapping dev_id -> device_details
116 */
117 __le64 device_details_root;
118
119 __le32 data_block_size; /* In 512-byte sectors. */
120
121 __le32 metadata_block_size; /* In 512-byte sectors. */
122 __le64 metadata_nr_blocks;
123
124 __le32 compat_flags;
125 __le32 compat_ro_flags;
126 __le32 incompat_flags;
127} __packed;
128
129struct disk_device_details {
130 __le64 mapped_blocks;
131 __le64 transaction_id; /* When created. */
132 __le32 creation_time;
133 __le32 snapshotted_time;
134} __packed;
135
136struct dm_pool_metadata {
137 struct hlist_node hash;
138
139 struct block_device *bdev;
140 struct dm_block_manager *bm;
141 struct dm_space_map *metadata_sm;
142 struct dm_space_map *data_sm;
143 struct dm_transaction_manager *tm;
144 struct dm_transaction_manager *nb_tm;
145
146 /*
147 * Two-level btree.
148 * First level holds thin_dev_t.
149 * Second level holds mappings.
150 */
151 struct dm_btree_info info;
152
153 /*
154 * Non-blocking version of the above.
155 */
156 struct dm_btree_info nb_info;
157
158 /*
159 * Just the top level for deleting whole devices.
160 */
161 struct dm_btree_info tl_info;
162
163 /*
164 * Just the bottom level for creating new devices.
165 */
166 struct dm_btree_info bl_info;
167
168 /*
169 * Describes the device details btree.
170 */
171 struct dm_btree_info details_info;
172
173 struct rw_semaphore root_lock;
174 uint32_t time;
175 int need_commit;
176 dm_block_t root;
177 dm_block_t details_root;
178 struct list_head thin_devices;
179 uint64_t trans_id;
180 unsigned long flags;
181 sector_t data_block_size;
182};
183
184struct dm_thin_device {
185 struct list_head list;
186 struct dm_pool_metadata *pmd;
187 dm_thin_id id;
188
189 int open_count;
190 int changed;
191 uint64_t mapped_blocks;
192 uint64_t transaction_id;
193 uint32_t creation_time;
194 uint32_t snapshotted_time;
195};
196
197/*----------------------------------------------------------------
198 * superblock validator
199 *--------------------------------------------------------------*/
200
201#define SUPERBLOCK_CSUM_XOR 160774
202
203static void sb_prepare_for_write(struct dm_block_validator *v,
204 struct dm_block *b,
205 size_t block_size)
206{
207 struct thin_disk_superblock *disk_super = dm_block_data(b);
208
209 disk_super->blocknr = cpu_to_le64(dm_block_location(b));
210 disk_super->csum = cpu_to_le32(dm_bm_checksum(&disk_super->flags,
211 block_size - sizeof(__le32),
212 SUPERBLOCK_CSUM_XOR));
213}
214
215static int sb_check(struct dm_block_validator *v,
216 struct dm_block *b,
217 size_t block_size)
218{
219 struct thin_disk_superblock *disk_super = dm_block_data(b);
220 __le32 csum_le;
221
222 if (dm_block_location(b) != le64_to_cpu(disk_super->blocknr)) {
223 DMERR("sb_check failed: blocknr %llu: "
224 "wanted %llu", le64_to_cpu(disk_super->blocknr),
225 (unsigned long long)dm_block_location(b));
226 return -ENOTBLK;
227 }
228
229 if (le64_to_cpu(disk_super->magic) != THIN_SUPERBLOCK_MAGIC) {
230 DMERR("sb_check failed: magic %llu: "
231 "wanted %llu", le64_to_cpu(disk_super->magic),
232 (unsigned long long)THIN_SUPERBLOCK_MAGIC);
233 return -EILSEQ;
234 }
235
236 csum_le = cpu_to_le32(dm_bm_checksum(&disk_super->flags,
237 block_size - sizeof(__le32),
238 SUPERBLOCK_CSUM_XOR));
239 if (csum_le != disk_super->csum) {
240 DMERR("sb_check failed: csum %u: wanted %u",
241 le32_to_cpu(csum_le), le32_to_cpu(disk_super->csum));
242 return -EILSEQ;
243 }
244
245 return 0;
246}
247
248static struct dm_block_validator sb_validator = {
249 .name = "superblock",
250 .prepare_for_write = sb_prepare_for_write,
251 .check = sb_check
252};
253
254/*----------------------------------------------------------------
255 * Methods for the btree value types
256 *--------------------------------------------------------------*/
257
258static uint64_t pack_block_time(dm_block_t b, uint32_t t)
259{
260 return (b << 24) | t;
261}
262
263static void unpack_block_time(uint64_t v, dm_block_t *b, uint32_t *t)
264{
265 *b = v >> 24;
266 *t = v & ((1 << 24) - 1);
267}
268
269static void data_block_inc(void *context, void *value_le)
270{
271 struct dm_space_map *sm = context;
272 __le64 v_le;
273 uint64_t b;
274 uint32_t t;
275
276 memcpy(&v_le, value_le, sizeof(v_le));
277 unpack_block_time(le64_to_cpu(v_le), &b, &t);
278 dm_sm_inc_block(sm, b);
279}
280
281static void data_block_dec(void *context, void *value_le)
282{
283 struct dm_space_map *sm = context;
284 __le64 v_le;
285 uint64_t b;
286 uint32_t t;
287
288 memcpy(&v_le, value_le, sizeof(v_le));
289 unpack_block_time(le64_to_cpu(v_le), &b, &t);
290 dm_sm_dec_block(sm, b);
291}
292
293static int data_block_equal(void *context, void *value1_le, void *value2_le)
294{
295 __le64 v1_le, v2_le;
296 uint64_t b1, b2;
297 uint32_t t;
298
299 memcpy(&v1_le, value1_le, sizeof(v1_le));
300 memcpy(&v2_le, value2_le, sizeof(v2_le));
301 unpack_block_time(le64_to_cpu(v1_le), &b1, &t);
302 unpack_block_time(le64_to_cpu(v2_le), &b2, &t);
303
304 return b1 == b2;
305}
306
307static void subtree_inc(void *context, void *value)
308{
309 struct dm_btree_info *info = context;
310 __le64 root_le;
311 uint64_t root;
312
313 memcpy(&root_le, value, sizeof(root_le));
314 root = le64_to_cpu(root_le);
315 dm_tm_inc(info->tm, root);
316}
317
318static void subtree_dec(void *context, void *value)
319{
320 struct dm_btree_info *info = context;
321 __le64 root_le;
322 uint64_t root;
323
324 memcpy(&root_le, value, sizeof(root_le));
325 root = le64_to_cpu(root_le);
326 if (dm_btree_del(info, root))
327 DMERR("btree delete failed\n");
328}
329
330static int subtree_equal(void *context, void *value1_le, void *value2_le)
331{
332 __le64 v1_le, v2_le;
333 memcpy(&v1_le, value1_le, sizeof(v1_le));
334 memcpy(&v2_le, value2_le, sizeof(v2_le));
335
336 return v1_le == v2_le;
337}
338
339/*----------------------------------------------------------------*/
340
341static int superblock_all_zeroes(struct dm_block_manager *bm, int *result)
342{
343 int r;
344 unsigned i;
345 struct dm_block *b;
346 __le64 *data_le, zero = cpu_to_le64(0);
347 unsigned block_size = dm_bm_block_size(bm) / sizeof(__le64);
348
349 /*
350 * We can't use a validator here - it may be all zeroes.
351 */
352 r = dm_bm_read_lock(bm, THIN_SUPERBLOCK_LOCATION, NULL, &b);
353 if (r)
354 return r;
355
356 data_le = dm_block_data(b);
357 *result = 1;
358 for (i = 0; i < block_size; i++) {
359 if (data_le[i] != zero) {
360 *result = 0;
361 break;
362 }
363 }
364
365 return dm_bm_unlock(b);
366}
367
368static int init_pmd(struct dm_pool_metadata *pmd,
369 struct dm_block_manager *bm,
370 dm_block_t nr_blocks, int create)
371{
372 int r;
373 struct dm_space_map *sm, *data_sm;
374 struct dm_transaction_manager *tm;
375 struct dm_block *sblock;
376
377 if (create) {
378 r = dm_tm_create_with_sm(bm, THIN_SUPERBLOCK_LOCATION,
379 &sb_validator, &tm, &sm, &sblock);
380 if (r < 0) {
381 DMERR("tm_create_with_sm failed");
382 return r;
383 }
384
385 data_sm = dm_sm_disk_create(tm, nr_blocks);
386 if (IS_ERR(data_sm)) {
387 DMERR("sm_disk_create failed");
Joe Thornber4469a5f2012-03-07 19:09:43 +0000388 dm_tm_unlock(tm, sblock);
Joe Thornber991d9fa2011-10-31 20:21:18 +0000389 r = PTR_ERR(data_sm);
390 goto bad;
391 }
392 } else {
393 struct thin_disk_superblock *disk_super = NULL;
394 size_t space_map_root_offset =
395 offsetof(struct thin_disk_superblock, metadata_space_map_root);
396
397 r = dm_tm_open_with_sm(bm, THIN_SUPERBLOCK_LOCATION,
398 &sb_validator, space_map_root_offset,
399 SPACE_MAP_ROOT_SIZE, &tm, &sm, &sblock);
400 if (r < 0) {
401 DMERR("tm_open_with_sm failed");
402 return r;
403 }
404
405 disk_super = dm_block_data(sblock);
406 data_sm = dm_sm_disk_open(tm, disk_super->data_space_map_root,
407 sizeof(disk_super->data_space_map_root));
408 if (IS_ERR(data_sm)) {
409 DMERR("sm_disk_open failed");
410 r = PTR_ERR(data_sm);
411 goto bad;
412 }
413 }
414
415
416 r = dm_tm_unlock(tm, sblock);
417 if (r < 0) {
418 DMERR("couldn't unlock superblock");
419 goto bad_data_sm;
420 }
421
422 pmd->bm = bm;
423 pmd->metadata_sm = sm;
424 pmd->data_sm = data_sm;
425 pmd->tm = tm;
426 pmd->nb_tm = dm_tm_create_non_blocking_clone(tm);
427 if (!pmd->nb_tm) {
428 DMERR("could not create clone tm");
429 r = -ENOMEM;
430 goto bad_data_sm;
431 }
432
433 pmd->info.tm = tm;
434 pmd->info.levels = 2;
435 pmd->info.value_type.context = pmd->data_sm;
436 pmd->info.value_type.size = sizeof(__le64);
437 pmd->info.value_type.inc = data_block_inc;
438 pmd->info.value_type.dec = data_block_dec;
439 pmd->info.value_type.equal = data_block_equal;
440
441 memcpy(&pmd->nb_info, &pmd->info, sizeof(pmd->nb_info));
442 pmd->nb_info.tm = pmd->nb_tm;
443
444 pmd->tl_info.tm = tm;
445 pmd->tl_info.levels = 1;
446 pmd->tl_info.value_type.context = &pmd->info;
447 pmd->tl_info.value_type.size = sizeof(__le64);
448 pmd->tl_info.value_type.inc = subtree_inc;
449 pmd->tl_info.value_type.dec = subtree_dec;
450 pmd->tl_info.value_type.equal = subtree_equal;
451
452 pmd->bl_info.tm = tm;
453 pmd->bl_info.levels = 1;
454 pmd->bl_info.value_type.context = pmd->data_sm;
455 pmd->bl_info.value_type.size = sizeof(__le64);
456 pmd->bl_info.value_type.inc = data_block_inc;
457 pmd->bl_info.value_type.dec = data_block_dec;
458 pmd->bl_info.value_type.equal = data_block_equal;
459
460 pmd->details_info.tm = tm;
461 pmd->details_info.levels = 1;
462 pmd->details_info.value_type.context = NULL;
463 pmd->details_info.value_type.size = sizeof(struct disk_device_details);
464 pmd->details_info.value_type.inc = NULL;
465 pmd->details_info.value_type.dec = NULL;
466 pmd->details_info.value_type.equal = NULL;
467
468 pmd->root = 0;
469
470 init_rwsem(&pmd->root_lock);
471 pmd->time = 0;
472 pmd->need_commit = 0;
473 pmd->details_root = 0;
474 pmd->trans_id = 0;
475 pmd->flags = 0;
476 INIT_LIST_HEAD(&pmd->thin_devices);
477
478 return 0;
479
480bad_data_sm:
481 dm_sm_destroy(data_sm);
482bad:
483 dm_tm_destroy(tm);
484 dm_sm_destroy(sm);
485
486 return r;
487}
488
489static int __begin_transaction(struct dm_pool_metadata *pmd)
490{
491 int r;
492 u32 features;
493 struct thin_disk_superblock *disk_super;
494 struct dm_block *sblock;
495
496 /*
497 * __maybe_commit_transaction() resets these
498 */
499 WARN_ON(pmd->need_commit);
500
501 /*
502 * We re-read the superblock every time. Shouldn't need to do this
503 * really.
504 */
505 r = dm_bm_read_lock(pmd->bm, THIN_SUPERBLOCK_LOCATION,
506 &sb_validator, &sblock);
507 if (r)
508 return r;
509
510 disk_super = dm_block_data(sblock);
511 pmd->time = le32_to_cpu(disk_super->time);
512 pmd->root = le64_to_cpu(disk_super->data_mapping_root);
513 pmd->details_root = le64_to_cpu(disk_super->device_details_root);
514 pmd->trans_id = le64_to_cpu(disk_super->trans_id);
515 pmd->flags = le32_to_cpu(disk_super->flags);
516 pmd->data_block_size = le32_to_cpu(disk_super->data_block_size);
517
518 features = le32_to_cpu(disk_super->incompat_flags) & ~THIN_FEATURE_INCOMPAT_SUPP;
519 if (features) {
520 DMERR("could not access metadata due to "
521 "unsupported optional features (%lx).",
522 (unsigned long)features);
523 r = -EINVAL;
524 goto out;
525 }
526
527 /*
528 * Check for read-only metadata to skip the following RDWR checks.
529 */
530 if (get_disk_ro(pmd->bdev->bd_disk))
531 goto out;
532
533 features = le32_to_cpu(disk_super->compat_ro_flags) & ~THIN_FEATURE_COMPAT_RO_SUPP;
534 if (features) {
535 DMERR("could not access metadata RDWR due to "
536 "unsupported optional features (%lx).",
537 (unsigned long)features);
538 r = -EINVAL;
539 }
540
541out:
542 dm_bm_unlock(sblock);
543 return r;
544}
545
546static int __write_changed_details(struct dm_pool_metadata *pmd)
547{
548 int r;
549 struct dm_thin_device *td, *tmp;
550 struct disk_device_details details;
551 uint64_t key;
552
553 list_for_each_entry_safe(td, tmp, &pmd->thin_devices, list) {
554 if (!td->changed)
555 continue;
556
557 key = td->id;
558
559 details.mapped_blocks = cpu_to_le64(td->mapped_blocks);
560 details.transaction_id = cpu_to_le64(td->transaction_id);
561 details.creation_time = cpu_to_le32(td->creation_time);
562 details.snapshotted_time = cpu_to_le32(td->snapshotted_time);
563 __dm_bless_for_disk(&details);
564
565 r = dm_btree_insert(&pmd->details_info, pmd->details_root,
566 &key, &details, &pmd->details_root);
567 if (r)
568 return r;
569
570 if (td->open_count)
571 td->changed = 0;
572 else {
573 list_del(&td->list);
574 kfree(td);
575 }
576
577 pmd->need_commit = 1;
578 }
579
580 return 0;
581}
582
583static int __commit_transaction(struct dm_pool_metadata *pmd)
584{
585 /*
586 * FIXME: Associated pool should be made read-only on failure.
587 */
588 int r;
589 size_t metadata_len, data_len;
590 struct thin_disk_superblock *disk_super;
591 struct dm_block *sblock;
592
593 /*
594 * We need to know if the thin_disk_superblock exceeds a 512-byte sector.
595 */
596 BUILD_BUG_ON(sizeof(struct thin_disk_superblock) > 512);
597
598 r = __write_changed_details(pmd);
599 if (r < 0)
600 goto out;
601
602 if (!pmd->need_commit)
603 goto out;
604
605 r = dm_sm_commit(pmd->data_sm);
606 if (r < 0)
607 goto out;
608
609 r = dm_tm_pre_commit(pmd->tm);
610 if (r < 0)
611 goto out;
612
613 r = dm_sm_root_size(pmd->metadata_sm, &metadata_len);
614 if (r < 0)
615 goto out;
616
Joe Thornberfef838c2012-03-28 18:41:25 +0100617 r = dm_sm_root_size(pmd->data_sm, &data_len);
Joe Thornber991d9fa2011-10-31 20:21:18 +0000618 if (r < 0)
619 goto out;
620
621 r = dm_bm_write_lock(pmd->bm, THIN_SUPERBLOCK_LOCATION,
622 &sb_validator, &sblock);
623 if (r)
624 goto out;
625
626 disk_super = dm_block_data(sblock);
627 disk_super->time = cpu_to_le32(pmd->time);
628 disk_super->data_mapping_root = cpu_to_le64(pmd->root);
629 disk_super->device_details_root = cpu_to_le64(pmd->details_root);
630 disk_super->trans_id = cpu_to_le64(pmd->trans_id);
631 disk_super->flags = cpu_to_le32(pmd->flags);
632
633 r = dm_sm_copy_root(pmd->metadata_sm, &disk_super->metadata_space_map_root,
634 metadata_len);
635 if (r < 0)
636 goto out_locked;
637
638 r = dm_sm_copy_root(pmd->data_sm, &disk_super->data_space_map_root,
639 data_len);
640 if (r < 0)
641 goto out_locked;
642
643 r = dm_tm_commit(pmd->tm, sblock);
644 if (!r)
645 pmd->need_commit = 0;
646
647out:
648 return r;
649
650out_locked:
651 dm_bm_unlock(sblock);
652 return r;
653}
654
655struct dm_pool_metadata *dm_pool_metadata_open(struct block_device *bdev,
656 sector_t data_block_size)
657{
658 int r;
659 struct thin_disk_superblock *disk_super;
660 struct dm_pool_metadata *pmd;
661 sector_t bdev_size = i_size_read(bdev->bd_inode) >> SECTOR_SHIFT;
662 struct dm_block_manager *bm;
663 int create;
664 struct dm_block *sblock;
665
666 pmd = kmalloc(sizeof(*pmd), GFP_KERNEL);
667 if (!pmd) {
668 DMERR("could not allocate metadata struct");
669 return ERR_PTR(-ENOMEM);
670 }
671
672 /*
673 * Max hex locks:
674 * 3 for btree insert +
675 * 2 for btree lookup used within space map
676 */
677 bm = dm_block_manager_create(bdev, THIN_METADATA_BLOCK_SIZE,
678 THIN_METADATA_CACHE_SIZE, 5);
679 if (!bm) {
680 DMERR("could not create block manager");
681 kfree(pmd);
682 return ERR_PTR(-ENOMEM);
683 }
684
685 r = superblock_all_zeroes(bm, &create);
686 if (r) {
687 dm_block_manager_destroy(bm);
688 kfree(pmd);
689 return ERR_PTR(r);
690 }
691
692
693 r = init_pmd(pmd, bm, 0, create);
694 if (r) {
695 dm_block_manager_destroy(bm);
696 kfree(pmd);
697 return ERR_PTR(r);
698 }
699 pmd->bdev = bdev;
700
701 if (!create) {
702 r = __begin_transaction(pmd);
703 if (r < 0)
704 goto bad;
705 return pmd;
706 }
707
708 /*
709 * Create.
710 */
711 r = dm_bm_write_lock(pmd->bm, THIN_SUPERBLOCK_LOCATION,
712 &sb_validator, &sblock);
713 if (r)
714 goto bad;
715
Mike Snitzerc4a69ec2012-03-28 18:41:28 +0100716 if (bdev_size > THIN_METADATA_MAX_SECTORS)
717 bdev_size = THIN_METADATA_MAX_SECTORS;
718
Joe Thornber991d9fa2011-10-31 20:21:18 +0000719 disk_super = dm_block_data(sblock);
720 disk_super->magic = cpu_to_le64(THIN_SUPERBLOCK_MAGIC);
721 disk_super->version = cpu_to_le32(THIN_VERSION);
722 disk_super->time = 0;
723 disk_super->metadata_block_size = cpu_to_le32(THIN_METADATA_BLOCK_SIZE >> SECTOR_SHIFT);
724 disk_super->metadata_nr_blocks = cpu_to_le64(bdev_size >> SECTOR_TO_BLOCK_SHIFT);
725 disk_super->data_block_size = cpu_to_le32(data_block_size);
726
727 r = dm_bm_unlock(sblock);
728 if (r < 0)
729 goto bad;
730
731 r = dm_btree_empty(&pmd->info, &pmd->root);
732 if (r < 0)
733 goto bad;
734
735 r = dm_btree_empty(&pmd->details_info, &pmd->details_root);
736 if (r < 0) {
737 DMERR("couldn't create devices root");
738 goto bad;
739 }
740
741 pmd->flags = 0;
742 pmd->need_commit = 1;
743 r = dm_pool_commit_metadata(pmd);
744 if (r < 0) {
745 DMERR("%s: dm_pool_commit_metadata() failed, error = %d",
746 __func__, r);
747 goto bad;
748 }
749
750 return pmd;
751
752bad:
753 if (dm_pool_metadata_close(pmd) < 0)
754 DMWARN("%s: dm_pool_metadata_close() failed.", __func__);
755 return ERR_PTR(r);
756}
757
758int dm_pool_metadata_close(struct dm_pool_metadata *pmd)
759{
760 int r;
761 unsigned open_devices = 0;
762 struct dm_thin_device *td, *tmp;
763
764 down_read(&pmd->root_lock);
765 list_for_each_entry_safe(td, tmp, &pmd->thin_devices, list) {
766 if (td->open_count)
767 open_devices++;
768 else {
769 list_del(&td->list);
770 kfree(td);
771 }
772 }
773 up_read(&pmd->root_lock);
774
775 if (open_devices) {
776 DMERR("attempt to close pmd when %u device(s) are still open",
777 open_devices);
778 return -EBUSY;
779 }
780
781 r = __commit_transaction(pmd);
782 if (r < 0)
783 DMWARN("%s: __commit_transaction() failed, error = %d",
784 __func__, r);
785
786 dm_tm_destroy(pmd->tm);
787 dm_tm_destroy(pmd->nb_tm);
788 dm_block_manager_destroy(pmd->bm);
789 dm_sm_destroy(pmd->metadata_sm);
790 dm_sm_destroy(pmd->data_sm);
791 kfree(pmd);
792
793 return 0;
794}
795
Mike Snitzer1f3db252012-03-07 19:09:41 +0000796/*
797 * __open_device: Returns @td corresponding to device with id @dev,
798 * creating it if @create is set and incrementing @td->open_count.
799 * On failure, @td is undefined.
800 */
Joe Thornber991d9fa2011-10-31 20:21:18 +0000801static int __open_device(struct dm_pool_metadata *pmd,
802 dm_thin_id dev, int create,
803 struct dm_thin_device **td)
804{
805 int r, changed = 0;
806 struct dm_thin_device *td2;
807 uint64_t key = dev;
808 struct disk_device_details details_le;
809
810 /*
Mike Snitzer1f3db252012-03-07 19:09:41 +0000811 * If the device is already open, return it.
Joe Thornber991d9fa2011-10-31 20:21:18 +0000812 */
813 list_for_each_entry(td2, &pmd->thin_devices, list)
814 if (td2->id == dev) {
Mike Snitzer1f3db252012-03-07 19:09:41 +0000815 /*
816 * May not create an already-open device.
817 */
818 if (create)
819 return -EEXIST;
820
Joe Thornber991d9fa2011-10-31 20:21:18 +0000821 td2->open_count++;
822 *td = td2;
823 return 0;
824 }
825
826 /*
827 * Check the device exists.
828 */
829 r = dm_btree_lookup(&pmd->details_info, pmd->details_root,
830 &key, &details_le);
831 if (r) {
832 if (r != -ENODATA || !create)
833 return r;
834
Mike Snitzer1f3db252012-03-07 19:09:41 +0000835 /*
836 * Create new device.
837 */
Joe Thornber991d9fa2011-10-31 20:21:18 +0000838 changed = 1;
839 details_le.mapped_blocks = 0;
840 details_le.transaction_id = cpu_to_le64(pmd->trans_id);
841 details_le.creation_time = cpu_to_le32(pmd->time);
842 details_le.snapshotted_time = cpu_to_le32(pmd->time);
843 }
844
845 *td = kmalloc(sizeof(**td), GFP_NOIO);
846 if (!*td)
847 return -ENOMEM;
848
849 (*td)->pmd = pmd;
850 (*td)->id = dev;
851 (*td)->open_count = 1;
852 (*td)->changed = changed;
853 (*td)->mapped_blocks = le64_to_cpu(details_le.mapped_blocks);
854 (*td)->transaction_id = le64_to_cpu(details_le.transaction_id);
855 (*td)->creation_time = le32_to_cpu(details_le.creation_time);
856 (*td)->snapshotted_time = le32_to_cpu(details_le.snapshotted_time);
857
858 list_add(&(*td)->list, &pmd->thin_devices);
859
860 return 0;
861}
862
863static void __close_device(struct dm_thin_device *td)
864{
865 --td->open_count;
866}
867
868static int __create_thin(struct dm_pool_metadata *pmd,
869 dm_thin_id dev)
870{
871 int r;
872 dm_block_t dev_root;
873 uint64_t key = dev;
874 struct disk_device_details details_le;
875 struct dm_thin_device *td;
876 __le64 value;
877
878 r = dm_btree_lookup(&pmd->details_info, pmd->details_root,
879 &key, &details_le);
880 if (!r)
881 return -EEXIST;
882
883 /*
884 * Create an empty btree for the mappings.
885 */
886 r = dm_btree_empty(&pmd->bl_info, &dev_root);
887 if (r)
888 return r;
889
890 /*
891 * Insert it into the main mapping tree.
892 */
893 value = cpu_to_le64(dev_root);
894 __dm_bless_for_disk(&value);
895 r = dm_btree_insert(&pmd->tl_info, pmd->root, &key, &value, &pmd->root);
896 if (r) {
897 dm_btree_del(&pmd->bl_info, dev_root);
898 return r;
899 }
900
901 r = __open_device(pmd, dev, 1, &td);
902 if (r) {
Joe Thornber991d9fa2011-10-31 20:21:18 +0000903 dm_btree_remove(&pmd->tl_info, pmd->root, &key, &pmd->root);
904 dm_btree_del(&pmd->bl_info, dev_root);
905 return r;
906 }
Joe Thornber991d9fa2011-10-31 20:21:18 +0000907 __close_device(td);
908
909 return r;
910}
911
912int dm_pool_create_thin(struct dm_pool_metadata *pmd, dm_thin_id dev)
913{
914 int r;
915
916 down_write(&pmd->root_lock);
917 r = __create_thin(pmd, dev);
918 up_write(&pmd->root_lock);
919
920 return r;
921}
922
923static int __set_snapshot_details(struct dm_pool_metadata *pmd,
924 struct dm_thin_device *snap,
925 dm_thin_id origin, uint32_t time)
926{
927 int r;
928 struct dm_thin_device *td;
929
930 r = __open_device(pmd, origin, 0, &td);
931 if (r)
932 return r;
933
934 td->changed = 1;
935 td->snapshotted_time = time;
936
937 snap->mapped_blocks = td->mapped_blocks;
938 snap->snapshotted_time = time;
939 __close_device(td);
940
941 return 0;
942}
943
944static int __create_snap(struct dm_pool_metadata *pmd,
945 dm_thin_id dev, dm_thin_id origin)
946{
947 int r;
948 dm_block_t origin_root;
949 uint64_t key = origin, dev_key = dev;
950 struct dm_thin_device *td;
951 struct disk_device_details details_le;
952 __le64 value;
953
954 /* check this device is unused */
955 r = dm_btree_lookup(&pmd->details_info, pmd->details_root,
956 &dev_key, &details_le);
957 if (!r)
958 return -EEXIST;
959
960 /* find the mapping tree for the origin */
961 r = dm_btree_lookup(&pmd->tl_info, pmd->root, &key, &value);
962 if (r)
963 return r;
964 origin_root = le64_to_cpu(value);
965
966 /* clone the origin, an inc will do */
967 dm_tm_inc(pmd->tm, origin_root);
968
969 /* insert into the main mapping tree */
970 value = cpu_to_le64(origin_root);
971 __dm_bless_for_disk(&value);
972 key = dev;
973 r = dm_btree_insert(&pmd->tl_info, pmd->root, &key, &value, &pmd->root);
974 if (r) {
975 dm_tm_dec(pmd->tm, origin_root);
976 return r;
977 }
978
979 pmd->time++;
980
981 r = __open_device(pmd, dev, 1, &td);
982 if (r)
983 goto bad;
984
985 r = __set_snapshot_details(pmd, td, origin, pmd->time);
Mike Snitzer1f3db252012-03-07 19:09:41 +0000986 __close_device(td);
987
Joe Thornber991d9fa2011-10-31 20:21:18 +0000988 if (r)
989 goto bad;
990
Joe Thornber991d9fa2011-10-31 20:21:18 +0000991 return 0;
992
993bad:
Joe Thornber991d9fa2011-10-31 20:21:18 +0000994 dm_btree_remove(&pmd->tl_info, pmd->root, &key, &pmd->root);
995 dm_btree_remove(&pmd->details_info, pmd->details_root,
996 &key, &pmd->details_root);
997 return r;
998}
999
1000int dm_pool_create_snap(struct dm_pool_metadata *pmd,
1001 dm_thin_id dev,
1002 dm_thin_id origin)
1003{
1004 int r;
1005
1006 down_write(&pmd->root_lock);
1007 r = __create_snap(pmd, dev, origin);
1008 up_write(&pmd->root_lock);
1009
1010 return r;
1011}
1012
1013static int __delete_device(struct dm_pool_metadata *pmd, dm_thin_id dev)
1014{
1015 int r;
1016 uint64_t key = dev;
1017 struct dm_thin_device *td;
1018
1019 /* TODO: failure should mark the transaction invalid */
1020 r = __open_device(pmd, dev, 0, &td);
1021 if (r)
1022 return r;
1023
1024 if (td->open_count > 1) {
1025 __close_device(td);
1026 return -EBUSY;
1027 }
1028
1029 list_del(&td->list);
1030 kfree(td);
1031 r = dm_btree_remove(&pmd->details_info, pmd->details_root,
1032 &key, &pmd->details_root);
1033 if (r)
1034 return r;
1035
1036 r = dm_btree_remove(&pmd->tl_info, pmd->root, &key, &pmd->root);
1037 if (r)
1038 return r;
1039
1040 pmd->need_commit = 1;
1041
1042 return 0;
1043}
1044
1045int dm_pool_delete_thin_device(struct dm_pool_metadata *pmd,
1046 dm_thin_id dev)
1047{
1048 int r;
1049
1050 down_write(&pmd->root_lock);
1051 r = __delete_device(pmd, dev);
1052 up_write(&pmd->root_lock);
1053
1054 return r;
1055}
1056
1057int dm_pool_set_metadata_transaction_id(struct dm_pool_metadata *pmd,
1058 uint64_t current_id,
1059 uint64_t new_id)
1060{
1061 down_write(&pmd->root_lock);
1062 if (pmd->trans_id != current_id) {
1063 up_write(&pmd->root_lock);
1064 DMERR("mismatched transaction id");
1065 return -EINVAL;
1066 }
1067
1068 pmd->trans_id = new_id;
1069 pmd->need_commit = 1;
1070 up_write(&pmd->root_lock);
1071
1072 return 0;
1073}
1074
1075int dm_pool_get_metadata_transaction_id(struct dm_pool_metadata *pmd,
1076 uint64_t *result)
1077{
1078 down_read(&pmd->root_lock);
1079 *result = pmd->trans_id;
1080 up_read(&pmd->root_lock);
1081
1082 return 0;
1083}
1084
1085static int __get_held_metadata_root(struct dm_pool_metadata *pmd,
1086 dm_block_t *result)
1087{
1088 int r;
1089 struct thin_disk_superblock *disk_super;
1090 struct dm_block *sblock;
1091
1092 r = dm_bm_write_lock(pmd->bm, THIN_SUPERBLOCK_LOCATION,
1093 &sb_validator, &sblock);
1094 if (r)
1095 return r;
1096
1097 disk_super = dm_block_data(sblock);
1098 *result = le64_to_cpu(disk_super->held_root);
1099
1100 return dm_bm_unlock(sblock);
1101}
1102
1103int dm_pool_get_held_metadata_root(struct dm_pool_metadata *pmd,
1104 dm_block_t *result)
1105{
1106 int r;
1107
1108 down_read(&pmd->root_lock);
1109 r = __get_held_metadata_root(pmd, result);
1110 up_read(&pmd->root_lock);
1111
1112 return r;
1113}
1114
1115int dm_pool_open_thin_device(struct dm_pool_metadata *pmd, dm_thin_id dev,
1116 struct dm_thin_device **td)
1117{
1118 int r;
1119
1120 down_write(&pmd->root_lock);
1121 r = __open_device(pmd, dev, 0, td);
1122 up_write(&pmd->root_lock);
1123
1124 return r;
1125}
1126
1127int dm_pool_close_thin_device(struct dm_thin_device *td)
1128{
1129 down_write(&td->pmd->root_lock);
1130 __close_device(td);
1131 up_write(&td->pmd->root_lock);
1132
1133 return 0;
1134}
1135
1136dm_thin_id dm_thin_dev_id(struct dm_thin_device *td)
1137{
1138 return td->id;
1139}
1140
1141static int __snapshotted_since(struct dm_thin_device *td, uint32_t time)
1142{
1143 return td->snapshotted_time > time;
1144}
1145
1146int dm_thin_find_block(struct dm_thin_device *td, dm_block_t block,
1147 int can_block, struct dm_thin_lookup_result *result)
1148{
1149 int r;
1150 uint64_t block_time = 0;
1151 __le64 value;
1152 struct dm_pool_metadata *pmd = td->pmd;
1153 dm_block_t keys[2] = { td->id, block };
1154
1155 if (can_block) {
1156 down_read(&pmd->root_lock);
1157 r = dm_btree_lookup(&pmd->info, pmd->root, keys, &value);
1158 if (!r)
1159 block_time = le64_to_cpu(value);
1160 up_read(&pmd->root_lock);
1161
1162 } else if (down_read_trylock(&pmd->root_lock)) {
1163 r = dm_btree_lookup(&pmd->nb_info, pmd->root, keys, &value);
1164 if (!r)
1165 block_time = le64_to_cpu(value);
1166 up_read(&pmd->root_lock);
1167
1168 } else
1169 return -EWOULDBLOCK;
1170
1171 if (!r) {
1172 dm_block_t exception_block;
1173 uint32_t exception_time;
1174 unpack_block_time(block_time, &exception_block,
1175 &exception_time);
1176 result->block = exception_block;
1177 result->shared = __snapshotted_since(td, exception_time);
1178 }
1179
1180 return r;
1181}
1182
1183static int __insert(struct dm_thin_device *td, dm_block_t block,
1184 dm_block_t data_block)
1185{
1186 int r, inserted;
1187 __le64 value;
1188 struct dm_pool_metadata *pmd = td->pmd;
1189 dm_block_t keys[2] = { td->id, block };
1190
1191 pmd->need_commit = 1;
1192 value = cpu_to_le64(pack_block_time(data_block, pmd->time));
1193 __dm_bless_for_disk(&value);
1194
1195 r = dm_btree_insert_notify(&pmd->info, pmd->root, keys, &value,
1196 &pmd->root, &inserted);
1197 if (r)
1198 return r;
1199
1200 if (inserted) {
1201 td->mapped_blocks++;
1202 td->changed = 1;
1203 }
1204
1205 return 0;
1206}
1207
1208int dm_thin_insert_block(struct dm_thin_device *td, dm_block_t block,
1209 dm_block_t data_block)
1210{
1211 int r;
1212
1213 down_write(&td->pmd->root_lock);
1214 r = __insert(td, block, data_block);
1215 up_write(&td->pmd->root_lock);
1216
1217 return r;
1218}
1219
1220static int __remove(struct dm_thin_device *td, dm_block_t block)
1221{
1222 int r;
1223 struct dm_pool_metadata *pmd = td->pmd;
1224 dm_block_t keys[2] = { td->id, block };
1225
1226 r = dm_btree_remove(&pmd->info, pmd->root, keys, &pmd->root);
1227 if (r)
1228 return r;
1229
Joe Thornberaf63bcb2012-03-07 19:09:44 +00001230 td->mapped_blocks--;
1231 td->changed = 1;
Joe Thornber991d9fa2011-10-31 20:21:18 +00001232 pmd->need_commit = 1;
1233
1234 return 0;
1235}
1236
1237int dm_thin_remove_block(struct dm_thin_device *td, dm_block_t block)
1238{
1239 int r;
1240
1241 down_write(&td->pmd->root_lock);
1242 r = __remove(td, block);
1243 up_write(&td->pmd->root_lock);
1244
1245 return r;
1246}
1247
1248int dm_pool_alloc_data_block(struct dm_pool_metadata *pmd, dm_block_t *result)
1249{
1250 int r;
1251
1252 down_write(&pmd->root_lock);
1253
1254 r = dm_sm_new_block(pmd->data_sm, result);
1255 pmd->need_commit = 1;
1256
1257 up_write(&pmd->root_lock);
1258
1259 return r;
1260}
1261
1262int dm_pool_commit_metadata(struct dm_pool_metadata *pmd)
1263{
1264 int r;
1265
1266 down_write(&pmd->root_lock);
1267
1268 r = __commit_transaction(pmd);
1269 if (r <= 0)
1270 goto out;
1271
1272 /*
1273 * Open the next transaction.
1274 */
1275 r = __begin_transaction(pmd);
1276out:
1277 up_write(&pmd->root_lock);
1278 return r;
1279}
1280
1281int dm_pool_get_free_block_count(struct dm_pool_metadata *pmd, dm_block_t *result)
1282{
1283 int r;
1284
1285 down_read(&pmd->root_lock);
1286 r = dm_sm_get_nr_free(pmd->data_sm, result);
1287 up_read(&pmd->root_lock);
1288
1289 return r;
1290}
1291
1292int dm_pool_get_free_metadata_block_count(struct dm_pool_metadata *pmd,
1293 dm_block_t *result)
1294{
1295 int r;
1296
1297 down_read(&pmd->root_lock);
1298 r = dm_sm_get_nr_free(pmd->metadata_sm, result);
1299 up_read(&pmd->root_lock);
1300
1301 return r;
1302}
1303
1304int dm_pool_get_metadata_dev_size(struct dm_pool_metadata *pmd,
1305 dm_block_t *result)
1306{
1307 int r;
1308
1309 down_read(&pmd->root_lock);
1310 r = dm_sm_get_nr_blocks(pmd->metadata_sm, result);
1311 up_read(&pmd->root_lock);
1312
1313 return r;
1314}
1315
1316int dm_pool_get_data_block_size(struct dm_pool_metadata *pmd, sector_t *result)
1317{
1318 down_read(&pmd->root_lock);
1319 *result = pmd->data_block_size;
1320 up_read(&pmd->root_lock);
1321
1322 return 0;
1323}
1324
1325int dm_pool_get_data_dev_size(struct dm_pool_metadata *pmd, dm_block_t *result)
1326{
1327 int r;
1328
1329 down_read(&pmd->root_lock);
1330 r = dm_sm_get_nr_blocks(pmd->data_sm, result);
1331 up_read(&pmd->root_lock);
1332
1333 return r;
1334}
1335
1336int dm_thin_get_mapped_count(struct dm_thin_device *td, dm_block_t *result)
1337{
1338 struct dm_pool_metadata *pmd = td->pmd;
1339
1340 down_read(&pmd->root_lock);
1341 *result = td->mapped_blocks;
1342 up_read(&pmd->root_lock);
1343
1344 return 0;
1345}
1346
1347static int __highest_block(struct dm_thin_device *td, dm_block_t *result)
1348{
1349 int r;
1350 __le64 value_le;
1351 dm_block_t thin_root;
1352 struct dm_pool_metadata *pmd = td->pmd;
1353
1354 r = dm_btree_lookup(&pmd->tl_info, pmd->root, &td->id, &value_le);
1355 if (r)
1356 return r;
1357
1358 thin_root = le64_to_cpu(value_le);
1359
1360 return dm_btree_find_highest_key(&pmd->bl_info, thin_root, result);
1361}
1362
1363int dm_thin_get_highest_mapped_block(struct dm_thin_device *td,
1364 dm_block_t *result)
1365{
1366 int r;
1367 struct dm_pool_metadata *pmd = td->pmd;
1368
1369 down_read(&pmd->root_lock);
1370 r = __highest_block(td, result);
1371 up_read(&pmd->root_lock);
1372
1373 return r;
1374}
1375
1376static int __resize_data_dev(struct dm_pool_metadata *pmd, dm_block_t new_count)
1377{
1378 int r;
1379 dm_block_t old_count;
1380
1381 r = dm_sm_get_nr_blocks(pmd->data_sm, &old_count);
1382 if (r)
1383 return r;
1384
1385 if (new_count == old_count)
1386 return 0;
1387
1388 if (new_count < old_count) {
1389 DMERR("cannot reduce size of data device");
1390 return -EINVAL;
1391 }
1392
1393 r = dm_sm_extend(pmd->data_sm, new_count - old_count);
1394 if (!r)
1395 pmd->need_commit = 1;
1396
1397 return r;
1398}
1399
1400int dm_pool_resize_data_dev(struct dm_pool_metadata *pmd, dm_block_t new_count)
1401{
1402 int r;
1403
1404 down_write(&pmd->root_lock);
1405 r = __resize_data_dev(pmd, new_count);
1406 up_write(&pmd->root_lock);
1407
1408 return r;
1409}