Root/drivers/md/dm-thin-metadata.c

1/*
2 * Copyright (C) 2011-2012 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/*
84 * 3 for btree insert +
85 * 2 for btree lookup used within space map
86 */
87#define THIN_MAX_CONCURRENT_LOCKS 5
88
89/* This should be plenty */
90#define SPACE_MAP_ROOT_SIZE 128
91
92/*
93 * Little endian on-disk superblock and device details.
94 */
95struct thin_disk_superblock {
96    __le32 csum; /* Checksum of superblock except for this field. */
97    __le32 flags;
98    __le64 blocknr; /* This block number, dm_block_t. */
99
100    __u8 uuid[16];
101    __le64 magic;
102    __le32 version;
103    __le32 time;
104
105    __le64 trans_id;
106
107    /*
108     * Root held by userspace transactions.
109     */
110    __le64 held_root;
111
112    __u8 data_space_map_root[SPACE_MAP_ROOT_SIZE];
113    __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
114
115    /*
116     * 2-level btree mapping (dev_id, (dev block, time)) -> data block
117     */
118    __le64 data_mapping_root;
119
120    /*
121     * Device detail root mapping dev_id -> device_details
122     */
123    __le64 device_details_root;
124
125    __le32 data_block_size; /* In 512-byte sectors. */
126
127    __le32 metadata_block_size; /* In 512-byte sectors. */
128    __le64 metadata_nr_blocks;
129
130    __le32 compat_flags;
131    __le32 compat_ro_flags;
132    __le32 incompat_flags;
133} __packed;
134
135struct disk_device_details {
136    __le64 mapped_blocks;
137    __le64 transaction_id; /* When created. */
138    __le32 creation_time;
139    __le32 snapshotted_time;
140} __packed;
141
142struct dm_pool_metadata {
143    struct hlist_node hash;
144
145    struct block_device *bdev;
146    struct dm_block_manager *bm;
147    struct dm_space_map *metadata_sm;
148    struct dm_space_map *data_sm;
149    struct dm_transaction_manager *tm;
150    struct dm_transaction_manager *nb_tm;
151
152    /*
153     * Two-level btree.
154     * First level holds thin_dev_t.
155     * Second level holds mappings.
156     */
157    struct dm_btree_info info;
158
159    /*
160     * Non-blocking version of the above.
161     */
162    struct dm_btree_info nb_info;
163
164    /*
165     * Just the top level for deleting whole devices.
166     */
167    struct dm_btree_info tl_info;
168
169    /*
170     * Just the bottom level for creating new devices.
171     */
172    struct dm_btree_info bl_info;
173
174    /*
175     * Describes the device details btree.
176     */
177    struct dm_btree_info details_info;
178
179    struct rw_semaphore root_lock;
180    uint32_t time;
181    dm_block_t root;
182    dm_block_t details_root;
183    struct list_head thin_devices;
184    uint64_t trans_id;
185    unsigned long flags;
186    sector_t data_block_size;
187    bool read_only:1;
188
189    /*
190     * Set if a transaction has to be aborted but the attempt to roll back
191     * to the previous (good) transaction failed. The only pool metadata
192     * operation possible in this state is the closing of the device.
193     */
194    bool fail_io:1;
195};
196
197struct dm_thin_device {
198    struct list_head list;
199    struct dm_pool_metadata *pmd;
200    dm_thin_id id;
201
202    int open_count;
203    bool changed:1;
204    bool aborted_with_changes:1;
205    uint64_t mapped_blocks;
206    uint64_t transaction_id;
207    uint32_t creation_time;
208    uint32_t snapshotted_time;
209};
210
211/*----------------------------------------------------------------
212 * superblock validator
213 *--------------------------------------------------------------*/
214
215#define SUPERBLOCK_CSUM_XOR 160774
216
217static void sb_prepare_for_write(struct dm_block_validator *v,
218                 struct dm_block *b,
219                 size_t block_size)
220{
221    struct thin_disk_superblock *disk_super = dm_block_data(b);
222
223    disk_super->blocknr = cpu_to_le64(dm_block_location(b));
224    disk_super->csum = cpu_to_le32(dm_bm_checksum(&disk_super->flags,
225                              block_size - sizeof(__le32),
226                              SUPERBLOCK_CSUM_XOR));
227}
228
229static int sb_check(struct dm_block_validator *v,
230            struct dm_block *b,
231            size_t block_size)
232{
233    struct thin_disk_superblock *disk_super = dm_block_data(b);
234    __le32 csum_le;
235
236    if (dm_block_location(b) != le64_to_cpu(disk_super->blocknr)) {
237        DMERR("sb_check failed: blocknr %llu: "
238              "wanted %llu", le64_to_cpu(disk_super->blocknr),
239              (unsigned long long)dm_block_location(b));
240        return -ENOTBLK;
241    }
242
243    if (le64_to_cpu(disk_super->magic) != THIN_SUPERBLOCK_MAGIC) {
244        DMERR("sb_check failed: magic %llu: "
245              "wanted %llu", le64_to_cpu(disk_super->magic),
246              (unsigned long long)THIN_SUPERBLOCK_MAGIC);
247        return -EILSEQ;
248    }
249
250    csum_le = cpu_to_le32(dm_bm_checksum(&disk_super->flags,
251                         block_size - sizeof(__le32),
252                         SUPERBLOCK_CSUM_XOR));
253    if (csum_le != disk_super->csum) {
254        DMERR("sb_check failed: csum %u: wanted %u",
255              le32_to_cpu(csum_le), le32_to_cpu(disk_super->csum));
256        return -EILSEQ;
257    }
258
259    return 0;
260}
261
262static struct dm_block_validator sb_validator = {
263    .name = "superblock",
264    .prepare_for_write = sb_prepare_for_write,
265    .check = sb_check
266};
267
268/*----------------------------------------------------------------
269 * Methods for the btree value types
270 *--------------------------------------------------------------*/
271
272static uint64_t pack_block_time(dm_block_t b, uint32_t t)
273{
274    return (b << 24) | t;
275}
276
277static void unpack_block_time(uint64_t v, dm_block_t *b, uint32_t *t)
278{
279    *b = v >> 24;
280    *t = v & ((1 << 24) - 1);
281}
282
283static void data_block_inc(void *context, const void *value_le)
284{
285    struct dm_space_map *sm = context;
286    __le64 v_le;
287    uint64_t b;
288    uint32_t t;
289
290    memcpy(&v_le, value_le, sizeof(v_le));
291    unpack_block_time(le64_to_cpu(v_le), &b, &t);
292    dm_sm_inc_block(sm, b);
293}
294
295static void data_block_dec(void *context, const void *value_le)
296{
297    struct dm_space_map *sm = context;
298    __le64 v_le;
299    uint64_t b;
300    uint32_t t;
301
302    memcpy(&v_le, value_le, sizeof(v_le));
303    unpack_block_time(le64_to_cpu(v_le), &b, &t);
304    dm_sm_dec_block(sm, b);
305}
306
307static int data_block_equal(void *context, const void *value1_le, const void *value2_le)
308{
309    __le64 v1_le, v2_le;
310    uint64_t b1, b2;
311    uint32_t t;
312
313    memcpy(&v1_le, value1_le, sizeof(v1_le));
314    memcpy(&v2_le, value2_le, sizeof(v2_le));
315    unpack_block_time(le64_to_cpu(v1_le), &b1, &t);
316    unpack_block_time(le64_to_cpu(v2_le), &b2, &t);
317
318    return b1 == b2;
319}
320
321static void subtree_inc(void *context, const void *value)
322{
323    struct dm_btree_info *info = context;
324    __le64 root_le;
325    uint64_t root;
326
327    memcpy(&root_le, value, sizeof(root_le));
328    root = le64_to_cpu(root_le);
329    dm_tm_inc(info->tm, root);
330}
331
332static void subtree_dec(void *context, const void *value)
333{
334    struct dm_btree_info *info = context;
335    __le64 root_le;
336    uint64_t root;
337
338    memcpy(&root_le, value, sizeof(root_le));
339    root = le64_to_cpu(root_le);
340    if (dm_btree_del(info, root))
341        DMERR("btree delete failed\n");
342}
343
344static int subtree_equal(void *context, const void *value1_le, const void *value2_le)
345{
346    __le64 v1_le, v2_le;
347    memcpy(&v1_le, value1_le, sizeof(v1_le));
348    memcpy(&v2_le, value2_le, sizeof(v2_le));
349
350    return v1_le == v2_le;
351}
352
353/*----------------------------------------------------------------*/
354
355static int superblock_lock_zero(struct dm_pool_metadata *pmd,
356                struct dm_block **sblock)
357{
358    return dm_bm_write_lock_zero(pmd->bm, THIN_SUPERBLOCK_LOCATION,
359                     &sb_validator, sblock);
360}
361
362static int superblock_lock(struct dm_pool_metadata *pmd,
363               struct dm_block **sblock)
364{
365    return dm_bm_write_lock(pmd->bm, THIN_SUPERBLOCK_LOCATION,
366                &sb_validator, sblock);
367}
368
369static int __superblock_all_zeroes(struct dm_block_manager *bm, int *result)
370{
371    int r;
372    unsigned i;
373    struct dm_block *b;
374    __le64 *data_le, zero = cpu_to_le64(0);
375    unsigned block_size = dm_bm_block_size(bm) / sizeof(__le64);
376
377    /*
378     * We can't use a validator here - it may be all zeroes.
379     */
380    r = dm_bm_read_lock(bm, THIN_SUPERBLOCK_LOCATION, NULL, &b);
381    if (r)
382        return r;
383
384    data_le = dm_block_data(b);
385    *result = 1;
386    for (i = 0; i < block_size; i++) {
387        if (data_le[i] != zero) {
388            *result = 0;
389            break;
390        }
391    }
392
393    return dm_bm_unlock(b);
394}
395
396static void __setup_btree_details(struct dm_pool_metadata *pmd)
397{
398    pmd->info.tm = pmd->tm;
399    pmd->info.levels = 2;
400    pmd->info.value_type.context = pmd->data_sm;
401    pmd->info.value_type.size = sizeof(__le64);
402    pmd->info.value_type.inc = data_block_inc;
403    pmd->info.value_type.dec = data_block_dec;
404    pmd->info.value_type.equal = data_block_equal;
405
406    memcpy(&pmd->nb_info, &pmd->info, sizeof(pmd->nb_info));
407    pmd->nb_info.tm = pmd->nb_tm;
408
409    pmd->tl_info.tm = pmd->tm;
410    pmd->tl_info.levels = 1;
411    pmd->tl_info.value_type.context = &pmd->bl_info;
412    pmd->tl_info.value_type.size = sizeof(__le64);
413    pmd->tl_info.value_type.inc = subtree_inc;
414    pmd->tl_info.value_type.dec = subtree_dec;
415    pmd->tl_info.value_type.equal = subtree_equal;
416
417    pmd->bl_info.tm = pmd->tm;
418    pmd->bl_info.levels = 1;
419    pmd->bl_info.value_type.context = pmd->data_sm;
420    pmd->bl_info.value_type.size = sizeof(__le64);
421    pmd->bl_info.value_type.inc = data_block_inc;
422    pmd->bl_info.value_type.dec = data_block_dec;
423    pmd->bl_info.value_type.equal = data_block_equal;
424
425    pmd->details_info.tm = pmd->tm;
426    pmd->details_info.levels = 1;
427    pmd->details_info.value_type.context = NULL;
428    pmd->details_info.value_type.size = sizeof(struct disk_device_details);
429    pmd->details_info.value_type.inc = NULL;
430    pmd->details_info.value_type.dec = NULL;
431    pmd->details_info.value_type.equal = NULL;
432}
433
434static int __write_initial_superblock(struct dm_pool_metadata *pmd)
435{
436    int r;
437    struct dm_block *sblock;
438    size_t metadata_len, data_len;
439    struct thin_disk_superblock *disk_super;
440    sector_t bdev_size = i_size_read(pmd->bdev->bd_inode) >> SECTOR_SHIFT;
441
442    if (bdev_size > THIN_METADATA_MAX_SECTORS)
443        bdev_size = THIN_METADATA_MAX_SECTORS;
444
445    r = dm_sm_root_size(pmd->metadata_sm, &metadata_len);
446    if (r < 0)
447        return r;
448
449    r = dm_sm_root_size(pmd->data_sm, &data_len);
450    if (r < 0)
451        return r;
452
453    r = dm_sm_commit(pmd->data_sm);
454    if (r < 0)
455        return r;
456
457    r = dm_tm_pre_commit(pmd->tm);
458    if (r < 0)
459        return r;
460
461    r = superblock_lock_zero(pmd, &sblock);
462    if (r)
463        return r;
464
465    disk_super = dm_block_data(sblock);
466    disk_super->flags = 0;
467    memset(disk_super->uuid, 0, sizeof(disk_super->uuid));
468    disk_super->magic = cpu_to_le64(THIN_SUPERBLOCK_MAGIC);
469    disk_super->version = cpu_to_le32(THIN_VERSION);
470    disk_super->time = 0;
471    disk_super->trans_id = 0;
472    disk_super->held_root = 0;
473
474    r = dm_sm_copy_root(pmd->metadata_sm, &disk_super->metadata_space_map_root,
475                metadata_len);
476    if (r < 0)
477        goto bad_locked;
478
479    r = dm_sm_copy_root(pmd->data_sm, &disk_super->data_space_map_root,
480                data_len);
481    if (r < 0)
482        goto bad_locked;
483
484    disk_super->data_mapping_root = cpu_to_le64(pmd->root);
485    disk_super->device_details_root = cpu_to_le64(pmd->details_root);
486    disk_super->metadata_block_size = cpu_to_le32(THIN_METADATA_BLOCK_SIZE >> SECTOR_SHIFT);
487    disk_super->metadata_nr_blocks = cpu_to_le64(bdev_size >> SECTOR_TO_BLOCK_SHIFT);
488    disk_super->data_block_size = cpu_to_le32(pmd->data_block_size);
489
490    return dm_tm_commit(pmd->tm, sblock);
491
492bad_locked:
493    dm_bm_unlock(sblock);
494    return r;
495}
496
497static int __format_metadata(struct dm_pool_metadata *pmd)
498{
499    int r;
500
501    r = dm_tm_create_with_sm(pmd->bm, THIN_SUPERBLOCK_LOCATION,
502                 &pmd->tm, &pmd->metadata_sm);
503    if (r < 0) {
504        DMERR("tm_create_with_sm failed");
505        return r;
506    }
507
508    pmd->data_sm = dm_sm_disk_create(pmd->tm, 0);
509    if (IS_ERR(pmd->data_sm)) {
510        DMERR("sm_disk_create failed");
511        r = PTR_ERR(pmd->data_sm);
512        goto bad_cleanup_tm;
513    }
514
515    pmd->nb_tm = dm_tm_create_non_blocking_clone(pmd->tm);
516    if (!pmd->nb_tm) {
517        DMERR("could not create non-blocking clone tm");
518        r = -ENOMEM;
519        goto bad_cleanup_data_sm;
520    }
521
522    __setup_btree_details(pmd);
523
524    r = dm_btree_empty(&pmd->info, &pmd->root);
525    if (r < 0)
526        goto bad_cleanup_nb_tm;
527
528    r = dm_btree_empty(&pmd->details_info, &pmd->details_root);
529    if (r < 0) {
530        DMERR("couldn't create devices root");
531        goto bad_cleanup_nb_tm;
532    }
533
534    r = __write_initial_superblock(pmd);
535    if (r)
536        goto bad_cleanup_nb_tm;
537
538    return 0;
539
540bad_cleanup_nb_tm:
541    dm_tm_destroy(pmd->nb_tm);
542bad_cleanup_data_sm:
543    dm_sm_destroy(pmd->data_sm);
544bad_cleanup_tm:
545    dm_tm_destroy(pmd->tm);
546    dm_sm_destroy(pmd->metadata_sm);
547
548    return r;
549}
550
551static int __check_incompat_features(struct thin_disk_superblock *disk_super,
552                     struct dm_pool_metadata *pmd)
553{
554    uint32_t features;
555
556    features = le32_to_cpu(disk_super->incompat_flags) & ~THIN_FEATURE_INCOMPAT_SUPP;
557    if (features) {
558        DMERR("could not access metadata due to unsupported optional features (%lx).",
559              (unsigned long)features);
560        return -EINVAL;
561    }
562
563    /*
564     * Check for read-only metadata to skip the following RDWR checks.
565     */
566    if (get_disk_ro(pmd->bdev->bd_disk))
567        return 0;
568
569    features = le32_to_cpu(disk_super->compat_ro_flags) & ~THIN_FEATURE_COMPAT_RO_SUPP;
570    if (features) {
571        DMERR("could not access metadata RDWR due to unsupported optional features (%lx).",
572              (unsigned long)features);
573        return -EINVAL;
574    }
575
576    return 0;
577}
578
579static int __open_metadata(struct dm_pool_metadata *pmd)
580{
581    int r;
582    struct dm_block *sblock;
583    struct thin_disk_superblock *disk_super;
584
585    r = dm_bm_read_lock(pmd->bm, THIN_SUPERBLOCK_LOCATION,
586                &sb_validator, &sblock);
587    if (r < 0) {
588        DMERR("couldn't read superblock");
589        return r;
590    }
591
592    disk_super = dm_block_data(sblock);
593
594    r = __check_incompat_features(disk_super, pmd);
595    if (r < 0)
596        goto bad_unlock_sblock;
597
598    r = dm_tm_open_with_sm(pmd->bm, THIN_SUPERBLOCK_LOCATION,
599                   disk_super->metadata_space_map_root,
600                   sizeof(disk_super->metadata_space_map_root),
601                   &pmd->tm, &pmd->metadata_sm);
602    if (r < 0) {
603        DMERR("tm_open_with_sm failed");
604        goto bad_unlock_sblock;
605    }
606
607    pmd->data_sm = dm_sm_disk_open(pmd->tm, disk_super->data_space_map_root,
608                       sizeof(disk_super->data_space_map_root));
609    if (IS_ERR(pmd->data_sm)) {
610        DMERR("sm_disk_open failed");
611        r = PTR_ERR(pmd->data_sm);
612        goto bad_cleanup_tm;
613    }
614
615    pmd->nb_tm = dm_tm_create_non_blocking_clone(pmd->tm);
616    if (!pmd->nb_tm) {
617        DMERR("could not create non-blocking clone tm");
618        r = -ENOMEM;
619        goto bad_cleanup_data_sm;
620    }
621
622    __setup_btree_details(pmd);
623    return dm_bm_unlock(sblock);
624
625bad_cleanup_data_sm:
626    dm_sm_destroy(pmd->data_sm);
627bad_cleanup_tm:
628    dm_tm_destroy(pmd->tm);
629    dm_sm_destroy(pmd->metadata_sm);
630bad_unlock_sblock:
631    dm_bm_unlock(sblock);
632
633    return r;
634}
635
636static int __open_or_format_metadata(struct dm_pool_metadata *pmd, bool format_device)
637{
638    int r, unformatted;
639
640    r = __superblock_all_zeroes(pmd->bm, &unformatted);
641    if (r)
642        return r;
643
644    if (unformatted)
645        return format_device ? __format_metadata(pmd) : -EPERM;
646
647    return __open_metadata(pmd);
648}
649
650static int __create_persistent_data_objects(struct dm_pool_metadata *pmd, bool format_device)
651{
652    int r;
653
654    pmd->bm = dm_block_manager_create(pmd->bdev, THIN_METADATA_BLOCK_SIZE,
655                      THIN_METADATA_CACHE_SIZE,
656                      THIN_MAX_CONCURRENT_LOCKS);
657    if (IS_ERR(pmd->bm)) {
658        DMERR("could not create block manager");
659        return PTR_ERR(pmd->bm);
660    }
661
662    r = __open_or_format_metadata(pmd, format_device);
663    if (r)
664        dm_block_manager_destroy(pmd->bm);
665
666    return r;
667}
668
669static void __destroy_persistent_data_objects(struct dm_pool_metadata *pmd)
670{
671    dm_sm_destroy(pmd->data_sm);
672    dm_sm_destroy(pmd->metadata_sm);
673    dm_tm_destroy(pmd->nb_tm);
674    dm_tm_destroy(pmd->tm);
675    dm_block_manager_destroy(pmd->bm);
676}
677
678static int __begin_transaction(struct dm_pool_metadata *pmd)
679{
680    int r;
681    struct thin_disk_superblock *disk_super;
682    struct dm_block *sblock;
683
684    /*
685     * We re-read the superblock every time. Shouldn't need to do this
686     * really.
687     */
688    r = dm_bm_read_lock(pmd->bm, THIN_SUPERBLOCK_LOCATION,
689                &sb_validator, &sblock);
690    if (r)
691        return r;
692
693    disk_super = dm_block_data(sblock);
694    pmd->time = le32_to_cpu(disk_super->time);
695    pmd->root = le64_to_cpu(disk_super->data_mapping_root);
696    pmd->details_root = le64_to_cpu(disk_super->device_details_root);
697    pmd->trans_id = le64_to_cpu(disk_super->trans_id);
698    pmd->flags = le32_to_cpu(disk_super->flags);
699    pmd->data_block_size = le32_to_cpu(disk_super->data_block_size);
700
701    dm_bm_unlock(sblock);
702    return 0;
703}
704
705static int __write_changed_details(struct dm_pool_metadata *pmd)
706{
707    int r;
708    struct dm_thin_device *td, *tmp;
709    struct disk_device_details details;
710    uint64_t key;
711
712    list_for_each_entry_safe(td, tmp, &pmd->thin_devices, list) {
713        if (!td->changed)
714            continue;
715
716        key = td->id;
717
718        details.mapped_blocks = cpu_to_le64(td->mapped_blocks);
719        details.transaction_id = cpu_to_le64(td->transaction_id);
720        details.creation_time = cpu_to_le32(td->creation_time);
721        details.snapshotted_time = cpu_to_le32(td->snapshotted_time);
722        __dm_bless_for_disk(&details);
723
724        r = dm_btree_insert(&pmd->details_info, pmd->details_root,
725                    &key, &details, &pmd->details_root);
726        if (r)
727            return r;
728
729        if (td->open_count)
730            td->changed = 0;
731        else {
732            list_del(&td->list);
733            kfree(td);
734        }
735    }
736
737    return 0;
738}
739
740static int __commit_transaction(struct dm_pool_metadata *pmd)
741{
742    int r;
743    size_t metadata_len, data_len;
744    struct thin_disk_superblock *disk_super;
745    struct dm_block *sblock;
746
747    /*
748     * We need to know if the thin_disk_superblock exceeds a 512-byte sector.
749     */
750    BUILD_BUG_ON(sizeof(struct thin_disk_superblock) > 512);
751
752    r = __write_changed_details(pmd);
753    if (r < 0)
754        return r;
755
756    r = dm_sm_commit(pmd->data_sm);
757    if (r < 0)
758        return r;
759
760    r = dm_tm_pre_commit(pmd->tm);
761    if (r < 0)
762        return r;
763
764    r = dm_sm_root_size(pmd->metadata_sm, &metadata_len);
765    if (r < 0)
766        return r;
767
768    r = dm_sm_root_size(pmd->data_sm, &data_len);
769    if (r < 0)
770        return r;
771
772    r = superblock_lock(pmd, &sblock);
773    if (r)
774        return r;
775
776    disk_super = dm_block_data(sblock);
777    disk_super->time = cpu_to_le32(pmd->time);
778    disk_super->data_mapping_root = cpu_to_le64(pmd->root);
779    disk_super->device_details_root = cpu_to_le64(pmd->details_root);
780    disk_super->trans_id = cpu_to_le64(pmd->trans_id);
781    disk_super->flags = cpu_to_le32(pmd->flags);
782
783    r = dm_sm_copy_root(pmd->metadata_sm, &disk_super->metadata_space_map_root,
784                metadata_len);
785    if (r < 0)
786        goto out_locked;
787
788    r = dm_sm_copy_root(pmd->data_sm, &disk_super->data_space_map_root,
789                data_len);
790    if (r < 0)
791        goto out_locked;
792
793    return dm_tm_commit(pmd->tm, sblock);
794
795out_locked:
796    dm_bm_unlock(sblock);
797    return r;
798}
799
800struct dm_pool_metadata *dm_pool_metadata_open(struct block_device *bdev,
801                           sector_t data_block_size,
802                           bool format_device)
803{
804    int r;
805    struct dm_pool_metadata *pmd;
806
807    pmd = kmalloc(sizeof(*pmd), GFP_KERNEL);
808    if (!pmd) {
809        DMERR("could not allocate metadata struct");
810        return ERR_PTR(-ENOMEM);
811    }
812
813    init_rwsem(&pmd->root_lock);
814    pmd->time = 0;
815    INIT_LIST_HEAD(&pmd->thin_devices);
816    pmd->read_only = false;
817    pmd->fail_io = false;
818    pmd->bdev = bdev;
819    pmd->data_block_size = data_block_size;
820
821    r = __create_persistent_data_objects(pmd, format_device);
822    if (r) {
823        kfree(pmd);
824        return ERR_PTR(r);
825    }
826
827    r = __begin_transaction(pmd);
828    if (r < 0) {
829        if (dm_pool_metadata_close(pmd) < 0)
830            DMWARN("%s: dm_pool_metadata_close() failed.", __func__);
831        return ERR_PTR(r);
832    }
833
834    return pmd;
835}
836
837int dm_pool_metadata_close(struct dm_pool_metadata *pmd)
838{
839    int r;
840    unsigned open_devices = 0;
841    struct dm_thin_device *td, *tmp;
842
843    down_read(&pmd->root_lock);
844    list_for_each_entry_safe(td, tmp, &pmd->thin_devices, list) {
845        if (td->open_count)
846            open_devices++;
847        else {
848            list_del(&td->list);
849            kfree(td);
850        }
851    }
852    up_read(&pmd->root_lock);
853
854    if (open_devices) {
855        DMERR("attempt to close pmd when %u device(s) are still open",
856               open_devices);
857        return -EBUSY;
858    }
859
860    if (!pmd->read_only && !pmd->fail_io) {
861        r = __commit_transaction(pmd);
862        if (r < 0)
863            DMWARN("%s: __commit_transaction() failed, error = %d",
864                   __func__, r);
865    }
866
867    if (!pmd->fail_io)
868        __destroy_persistent_data_objects(pmd);
869
870    kfree(pmd);
871    return 0;
872}
873
874/*
875 * __open_device: Returns @td corresponding to device with id @dev,
876 * creating it if @create is set and incrementing @td->open_count.
877 * On failure, @td is undefined.
878 */
879static int __open_device(struct dm_pool_metadata *pmd,
880             dm_thin_id dev, int create,
881             struct dm_thin_device **td)
882{
883    int r, changed = 0;
884    struct dm_thin_device *td2;
885    uint64_t key = dev;
886    struct disk_device_details details_le;
887
888    /*
889     * If the device is already open, return it.
890     */
891    list_for_each_entry(td2, &pmd->thin_devices, list)
892        if (td2->id == dev) {
893            /*
894             * May not create an already-open device.
895             */
896            if (create)
897                return -EEXIST;
898
899            td2->open_count++;
900            *td = td2;
901            return 0;
902        }
903
904    /*
905     * Check the device exists.
906     */
907    r = dm_btree_lookup(&pmd->details_info, pmd->details_root,
908                &key, &details_le);
909    if (r) {
910        if (r != -ENODATA || !create)
911            return r;
912
913        /*
914         * Create new device.
915         */
916        changed = 1;
917        details_le.mapped_blocks = 0;
918        details_le.transaction_id = cpu_to_le64(pmd->trans_id);
919        details_le.creation_time = cpu_to_le32(pmd->time);
920        details_le.snapshotted_time = cpu_to_le32(pmd->time);
921    }
922
923    *td = kmalloc(sizeof(**td), GFP_NOIO);
924    if (!*td)
925        return -ENOMEM;
926
927    (*td)->pmd = pmd;
928    (*td)->id = dev;
929    (*td)->open_count = 1;
930    (*td)->changed = changed;
931    (*td)->aborted_with_changes = false;
932    (*td)->mapped_blocks = le64_to_cpu(details_le.mapped_blocks);
933    (*td)->transaction_id = le64_to_cpu(details_le.transaction_id);
934    (*td)->creation_time = le32_to_cpu(details_le.creation_time);
935    (*td)->snapshotted_time = le32_to_cpu(details_le.snapshotted_time);
936
937    list_add(&(*td)->list, &pmd->thin_devices);
938
939    return 0;
940}
941
942static void __close_device(struct dm_thin_device *td)
943{
944    --td->open_count;
945}
946
947static int __create_thin(struct dm_pool_metadata *pmd,
948             dm_thin_id dev)
949{
950    int r;
951    dm_block_t dev_root;
952    uint64_t key = dev;
953    struct disk_device_details details_le;
954    struct dm_thin_device *td;
955    __le64 value;
956
957    r = dm_btree_lookup(&pmd->details_info, pmd->details_root,
958                &key, &details_le);
959    if (!r)
960        return -EEXIST;
961
962    /*
963     * Create an empty btree for the mappings.
964     */
965    r = dm_btree_empty(&pmd->bl_info, &dev_root);
966    if (r)
967        return r;
968
969    /*
970     * Insert it into the main mapping tree.
971     */
972    value = cpu_to_le64(dev_root);
973    __dm_bless_for_disk(&value);
974    r = dm_btree_insert(&pmd->tl_info, pmd->root, &key, &value, &pmd->root);
975    if (r) {
976        dm_btree_del(&pmd->bl_info, dev_root);
977        return r;
978    }
979
980    r = __open_device(pmd, dev, 1, &td);
981    if (r) {
982        dm_btree_remove(&pmd->tl_info, pmd->root, &key, &pmd->root);
983        dm_btree_del(&pmd->bl_info, dev_root);
984        return r;
985    }
986    __close_device(td);
987
988    return r;
989}
990
991int dm_pool_create_thin(struct dm_pool_metadata *pmd, dm_thin_id dev)
992{
993    int r = -EINVAL;
994
995    down_write(&pmd->root_lock);
996    if (!pmd->fail_io)
997        r = __create_thin(pmd, dev);
998    up_write(&pmd->root_lock);
999
1000    return r;
1001}
1002
1003static int __set_snapshot_details(struct dm_pool_metadata *pmd,
1004                  struct dm_thin_device *snap,
1005                  dm_thin_id origin, uint32_t time)
1006{
1007    int r;
1008    struct dm_thin_device *td;
1009
1010    r = __open_device(pmd, origin, 0, &td);
1011    if (r)
1012        return r;
1013
1014    td->changed = 1;
1015    td->snapshotted_time = time;
1016
1017    snap->mapped_blocks = td->mapped_blocks;
1018    snap->snapshotted_time = time;
1019    __close_device(td);
1020
1021    return 0;
1022}
1023
1024static int __create_snap(struct dm_pool_metadata *pmd,
1025             dm_thin_id dev, dm_thin_id origin)
1026{
1027    int r;
1028    dm_block_t origin_root;
1029    uint64_t key = origin, dev_key = dev;
1030    struct dm_thin_device *td;
1031    struct disk_device_details details_le;
1032    __le64 value;
1033
1034    /* check this device is unused */
1035    r = dm_btree_lookup(&pmd->details_info, pmd->details_root,
1036                &dev_key, &details_le);
1037    if (!r)
1038        return -EEXIST;
1039
1040    /* find the mapping tree for the origin */
1041    r = dm_btree_lookup(&pmd->tl_info, pmd->root, &key, &value);
1042    if (r)
1043        return r;
1044    origin_root = le64_to_cpu(value);
1045
1046    /* clone the origin, an inc will do */
1047    dm_tm_inc(pmd->tm, origin_root);
1048
1049    /* insert into the main mapping tree */
1050    value = cpu_to_le64(origin_root);
1051    __dm_bless_for_disk(&value);
1052    key = dev;
1053    r = dm_btree_insert(&pmd->tl_info, pmd->root, &key, &value, &pmd->root);
1054    if (r) {
1055        dm_tm_dec(pmd->tm, origin_root);
1056        return r;
1057    }
1058
1059    pmd->time++;
1060
1061    r = __open_device(pmd, dev, 1, &td);
1062    if (r)
1063        goto bad;
1064
1065    r = __set_snapshot_details(pmd, td, origin, pmd->time);
1066    __close_device(td);
1067
1068    if (r)
1069        goto bad;
1070
1071    return 0;
1072
1073bad:
1074    dm_btree_remove(&pmd->tl_info, pmd->root, &key, &pmd->root);
1075    dm_btree_remove(&pmd->details_info, pmd->details_root,
1076            &key, &pmd->details_root);
1077    return r;
1078}
1079
1080int dm_pool_create_snap(struct dm_pool_metadata *pmd,
1081                 dm_thin_id dev,
1082                 dm_thin_id origin)
1083{
1084    int r = -EINVAL;
1085
1086    down_write(&pmd->root_lock);
1087    if (!pmd->fail_io)
1088        r = __create_snap(pmd, dev, origin);
1089    up_write(&pmd->root_lock);
1090
1091    return r;
1092}
1093
1094static int __delete_device(struct dm_pool_metadata *pmd, dm_thin_id dev)
1095{
1096    int r;
1097    uint64_t key = dev;
1098    struct dm_thin_device *td;
1099
1100    /* TODO: failure should mark the transaction invalid */
1101    r = __open_device(pmd, dev, 0, &td);
1102    if (r)
1103        return r;
1104
1105    if (td->open_count > 1) {
1106        __close_device(td);
1107        return -EBUSY;
1108    }
1109
1110    list_del(&td->list);
1111    kfree(td);
1112    r = dm_btree_remove(&pmd->details_info, pmd->details_root,
1113                &key, &pmd->details_root);
1114    if (r)
1115        return r;
1116
1117    r = dm_btree_remove(&pmd->tl_info, pmd->root, &key, &pmd->root);
1118    if (r)
1119        return r;
1120
1121    return 0;
1122}
1123
1124int dm_pool_delete_thin_device(struct dm_pool_metadata *pmd,
1125                   dm_thin_id dev)
1126{
1127    int r = -EINVAL;
1128
1129    down_write(&pmd->root_lock);
1130    if (!pmd->fail_io)
1131        r = __delete_device(pmd, dev);
1132    up_write(&pmd->root_lock);
1133
1134    return r;
1135}
1136
1137int dm_pool_set_metadata_transaction_id(struct dm_pool_metadata *pmd,
1138                    uint64_t current_id,
1139                    uint64_t new_id)
1140{
1141    int r = -EINVAL;
1142
1143    down_write(&pmd->root_lock);
1144
1145    if (pmd->fail_io)
1146        goto out;
1147
1148    if (pmd->trans_id != current_id) {
1149        DMERR("mismatched transaction id");
1150        goto out;
1151    }
1152
1153    pmd->trans_id = new_id;
1154    r = 0;
1155
1156out:
1157    up_write(&pmd->root_lock);
1158
1159    return r;
1160}
1161
1162int dm_pool_get_metadata_transaction_id(struct dm_pool_metadata *pmd,
1163                    uint64_t *result)
1164{
1165    int r = -EINVAL;
1166
1167    down_read(&pmd->root_lock);
1168    if (!pmd->fail_io) {
1169        *result = pmd->trans_id;
1170        r = 0;
1171    }
1172    up_read(&pmd->root_lock);
1173
1174    return r;
1175}
1176
1177static int __reserve_metadata_snap(struct dm_pool_metadata *pmd)
1178{
1179    int r, inc;
1180    struct thin_disk_superblock *disk_super;
1181    struct dm_block *copy, *sblock;
1182    dm_block_t held_root;
1183
1184    /*
1185     * Copy the superblock.
1186     */
1187    dm_sm_inc_block(pmd->metadata_sm, THIN_SUPERBLOCK_LOCATION);
1188    r = dm_tm_shadow_block(pmd->tm, THIN_SUPERBLOCK_LOCATION,
1189                   &sb_validator, &copy, &inc);
1190    if (r)
1191        return r;
1192
1193    BUG_ON(!inc);
1194
1195    held_root = dm_block_location(copy);
1196    disk_super = dm_block_data(copy);
1197
1198    if (le64_to_cpu(disk_super->held_root)) {
1199        DMWARN("Pool metadata snapshot already exists: release this before taking another.");
1200
1201        dm_tm_dec(pmd->tm, held_root);
1202        dm_tm_unlock(pmd->tm, copy);
1203        return -EBUSY;
1204    }
1205
1206    /*
1207     * Wipe the spacemap since we're not publishing this.
1208     */
1209    memset(&disk_super->data_space_map_root, 0,
1210           sizeof(disk_super->data_space_map_root));
1211    memset(&disk_super->metadata_space_map_root, 0,
1212           sizeof(disk_super->metadata_space_map_root));
1213
1214    /*
1215     * Increment the data structures that need to be preserved.
1216     */
1217    dm_tm_inc(pmd->tm, le64_to_cpu(disk_super->data_mapping_root));
1218    dm_tm_inc(pmd->tm, le64_to_cpu(disk_super->device_details_root));
1219    dm_tm_unlock(pmd->tm, copy);
1220
1221    /*
1222     * Write the held root into the superblock.
1223     */
1224    r = superblock_lock(pmd, &sblock);
1225    if (r) {
1226        dm_tm_dec(pmd->tm, held_root);
1227        return r;
1228    }
1229
1230    disk_super = dm_block_data(sblock);
1231    disk_super->held_root = cpu_to_le64(held_root);
1232    dm_bm_unlock(sblock);
1233    return 0;
1234}
1235
1236int dm_pool_reserve_metadata_snap(struct dm_pool_metadata *pmd)
1237{
1238    int r = -EINVAL;
1239
1240    down_write(&pmd->root_lock);
1241    if (!pmd->fail_io)
1242        r = __reserve_metadata_snap(pmd);
1243    up_write(&pmd->root_lock);
1244
1245    return r;
1246}
1247
1248static int __release_metadata_snap(struct dm_pool_metadata *pmd)
1249{
1250    int r;
1251    struct thin_disk_superblock *disk_super;
1252    struct dm_block *sblock, *copy;
1253    dm_block_t held_root;
1254
1255    r = superblock_lock(pmd, &sblock);
1256    if (r)
1257        return r;
1258
1259    disk_super = dm_block_data(sblock);
1260    held_root = le64_to_cpu(disk_super->held_root);
1261    disk_super->held_root = cpu_to_le64(0);
1262
1263    dm_bm_unlock(sblock);
1264
1265    if (!held_root) {
1266        DMWARN("No pool metadata snapshot found: nothing to release.");
1267        return -EINVAL;
1268    }
1269
1270    r = dm_tm_read_lock(pmd->tm, held_root, &sb_validator, &copy);
1271    if (r)
1272        return r;
1273
1274    disk_super = dm_block_data(copy);
1275    dm_sm_dec_block(pmd->metadata_sm, le64_to_cpu(disk_super->data_mapping_root));
1276    dm_sm_dec_block(pmd->metadata_sm, le64_to_cpu(disk_super->device_details_root));
1277    dm_sm_dec_block(pmd->metadata_sm, held_root);
1278
1279    return dm_tm_unlock(pmd->tm, copy);
1280}
1281
1282int dm_pool_release_metadata_snap(struct dm_pool_metadata *pmd)
1283{
1284    int r = -EINVAL;
1285
1286    down_write(&pmd->root_lock);
1287    if (!pmd->fail_io)
1288        r = __release_metadata_snap(pmd);
1289    up_write(&pmd->root_lock);
1290
1291    return r;
1292}
1293
1294static int __get_metadata_snap(struct dm_pool_metadata *pmd,
1295                   dm_block_t *result)
1296{
1297    int r;
1298    struct thin_disk_superblock *disk_super;
1299    struct dm_block *sblock;
1300
1301    r = dm_bm_read_lock(pmd->bm, THIN_SUPERBLOCK_LOCATION,
1302                &sb_validator, &sblock);
1303    if (r)
1304        return r;
1305
1306    disk_super = dm_block_data(sblock);
1307    *result = le64_to_cpu(disk_super->held_root);
1308
1309    return dm_bm_unlock(sblock);
1310}
1311
1312int dm_pool_get_metadata_snap(struct dm_pool_metadata *pmd,
1313                  dm_block_t *result)
1314{
1315    int r = -EINVAL;
1316
1317    down_read(&pmd->root_lock);
1318    if (!pmd->fail_io)
1319        r = __get_metadata_snap(pmd, result);
1320    up_read(&pmd->root_lock);
1321
1322    return r;
1323}
1324
1325int dm_pool_open_thin_device(struct dm_pool_metadata *pmd, dm_thin_id dev,
1326                 struct dm_thin_device **td)
1327{
1328    int r = -EINVAL;
1329
1330    down_write(&pmd->root_lock);
1331    if (!pmd->fail_io)
1332        r = __open_device(pmd, dev, 0, td);
1333    up_write(&pmd->root_lock);
1334
1335    return r;
1336}
1337
1338int dm_pool_close_thin_device(struct dm_thin_device *td)
1339{
1340    down_write(&td->pmd->root_lock);
1341    __close_device(td);
1342    up_write(&td->pmd->root_lock);
1343
1344    return 0;
1345}
1346
1347dm_thin_id dm_thin_dev_id(struct dm_thin_device *td)
1348{
1349    return td->id;
1350}
1351
1352static bool __snapshotted_since(struct dm_thin_device *td, uint32_t time)
1353{
1354    return td->snapshotted_time > time;
1355}
1356
1357int dm_thin_find_block(struct dm_thin_device *td, dm_block_t block,
1358               int can_block, struct dm_thin_lookup_result *result)
1359{
1360    int r = -EINVAL;
1361    uint64_t block_time = 0;
1362    __le64 value;
1363    struct dm_pool_metadata *pmd = td->pmd;
1364    dm_block_t keys[2] = { td->id, block };
1365    struct dm_btree_info *info;
1366
1367    if (can_block) {
1368        down_read(&pmd->root_lock);
1369        info = &pmd->info;
1370    } else if (down_read_trylock(&pmd->root_lock))
1371        info = &pmd->nb_info;
1372    else
1373        return -EWOULDBLOCK;
1374
1375    if (pmd->fail_io)
1376        goto out;
1377
1378    r = dm_btree_lookup(info, pmd->root, keys, &value);
1379    if (!r)
1380        block_time = le64_to_cpu(value);
1381
1382out:
1383    up_read(&pmd->root_lock);
1384
1385    if (!r) {
1386        dm_block_t exception_block;
1387        uint32_t exception_time;
1388        unpack_block_time(block_time, &exception_block,
1389                  &exception_time);
1390        result->block = exception_block;
1391        result->shared = __snapshotted_since(td, exception_time);
1392    }
1393
1394    return r;
1395}
1396
1397static int __insert(struct dm_thin_device *td, dm_block_t block,
1398            dm_block_t data_block)
1399{
1400    int r, inserted;
1401    __le64 value;
1402    struct dm_pool_metadata *pmd = td->pmd;
1403    dm_block_t keys[2] = { td->id, block };
1404
1405    value = cpu_to_le64(pack_block_time(data_block, pmd->time));
1406    __dm_bless_for_disk(&value);
1407
1408    r = dm_btree_insert_notify(&pmd->info, pmd->root, keys, &value,
1409                   &pmd->root, &inserted);
1410    if (r)
1411        return r;
1412
1413    td->changed = 1;
1414    if (inserted)
1415        td->mapped_blocks++;
1416
1417    return 0;
1418}
1419
1420int dm_thin_insert_block(struct dm_thin_device *td, dm_block_t block,
1421             dm_block_t data_block)
1422{
1423    int r = -EINVAL;
1424
1425    down_write(&td->pmd->root_lock);
1426    if (!td->pmd->fail_io)
1427        r = __insert(td, block, data_block);
1428    up_write(&td->pmd->root_lock);
1429
1430    return r;
1431}
1432
1433static int __remove(struct dm_thin_device *td, dm_block_t block)
1434{
1435    int r;
1436    struct dm_pool_metadata *pmd = td->pmd;
1437    dm_block_t keys[2] = { td->id, block };
1438
1439    r = dm_btree_remove(&pmd->info, pmd->root, keys, &pmd->root);
1440    if (r)
1441        return r;
1442
1443    td->mapped_blocks--;
1444    td->changed = 1;
1445
1446    return 0;
1447}
1448
1449int dm_thin_remove_block(struct dm_thin_device *td, dm_block_t block)
1450{
1451    int r = -EINVAL;
1452
1453    down_write(&td->pmd->root_lock);
1454    if (!td->pmd->fail_io)
1455        r = __remove(td, block);
1456    up_write(&td->pmd->root_lock);
1457
1458    return r;
1459}
1460
1461bool dm_thin_changed_this_transaction(struct dm_thin_device *td)
1462{
1463    int r;
1464
1465    down_read(&td->pmd->root_lock);
1466    r = td->changed;
1467    up_read(&td->pmd->root_lock);
1468
1469    return r;
1470}
1471
1472bool dm_thin_aborted_changes(struct dm_thin_device *td)
1473{
1474    bool r;
1475
1476    down_read(&td->pmd->root_lock);
1477    r = td->aborted_with_changes;
1478    up_read(&td->pmd->root_lock);
1479
1480    return r;
1481}
1482
1483int dm_pool_alloc_data_block(struct dm_pool_metadata *pmd, dm_block_t *result)
1484{
1485    int r = -EINVAL;
1486
1487    down_write(&pmd->root_lock);
1488    if (!pmd->fail_io)
1489        r = dm_sm_new_block(pmd->data_sm, result);
1490    up_write(&pmd->root_lock);
1491
1492    return r;
1493}
1494
1495int dm_pool_commit_metadata(struct dm_pool_metadata *pmd)
1496{
1497    int r = -EINVAL;
1498
1499    down_write(&pmd->root_lock);
1500    if (pmd->fail_io)
1501        goto out;
1502
1503    r = __commit_transaction(pmd);
1504    if (r <= 0)
1505        goto out;
1506
1507    /*
1508     * Open the next transaction.
1509     */
1510    r = __begin_transaction(pmd);
1511out:
1512    up_write(&pmd->root_lock);
1513    return r;
1514}
1515
1516static void __set_abort_with_changes_flags(struct dm_pool_metadata *pmd)
1517{
1518    struct dm_thin_device *td;
1519
1520    list_for_each_entry(td, &pmd->thin_devices, list)
1521        td->aborted_with_changes = td->changed;
1522}
1523
1524int dm_pool_abort_metadata(struct dm_pool_metadata *pmd)
1525{
1526    int r = -EINVAL;
1527
1528    down_write(&pmd->root_lock);
1529    if (pmd->fail_io)
1530        goto out;
1531
1532    __set_abort_with_changes_flags(pmd);
1533    __destroy_persistent_data_objects(pmd);
1534    r = __create_persistent_data_objects(pmd, false);
1535    if (r)
1536        pmd->fail_io = true;
1537
1538out:
1539    up_write(&pmd->root_lock);
1540
1541    return r;
1542}
1543
1544int dm_pool_get_free_block_count(struct dm_pool_metadata *pmd, dm_block_t *result)
1545{
1546    int r = -EINVAL;
1547
1548    down_read(&pmd->root_lock);
1549    if (!pmd->fail_io)
1550        r = dm_sm_get_nr_free(pmd->data_sm, result);
1551    up_read(&pmd->root_lock);
1552
1553    return r;
1554}
1555
1556int dm_pool_get_free_metadata_block_count(struct dm_pool_metadata *pmd,
1557                      dm_block_t *result)
1558{
1559    int r = -EINVAL;
1560
1561    down_read(&pmd->root_lock);
1562    if (!pmd->fail_io)
1563        r = dm_sm_get_nr_free(pmd->metadata_sm, result);
1564    up_read(&pmd->root_lock);
1565
1566    return r;
1567}
1568
1569int dm_pool_get_metadata_dev_size(struct dm_pool_metadata *pmd,
1570                  dm_block_t *result)
1571{
1572    int r = -EINVAL;
1573
1574    down_read(&pmd->root_lock);
1575    if (!pmd->fail_io)
1576        r = dm_sm_get_nr_blocks(pmd->metadata_sm, result);
1577    up_read(&pmd->root_lock);
1578
1579    return r;
1580}
1581
1582int dm_pool_get_data_block_size(struct dm_pool_metadata *pmd, sector_t *result)
1583{
1584    down_read(&pmd->root_lock);
1585    *result = pmd->data_block_size;
1586    up_read(&pmd->root_lock);
1587
1588    return 0;
1589}
1590
1591int dm_pool_get_data_dev_size(struct dm_pool_metadata *pmd, dm_block_t *result)
1592{
1593    int r = -EINVAL;
1594
1595    down_read(&pmd->root_lock);
1596    if (!pmd->fail_io)
1597        r = dm_sm_get_nr_blocks(pmd->data_sm, result);
1598    up_read(&pmd->root_lock);
1599
1600    return r;
1601}
1602
1603int dm_thin_get_mapped_count(struct dm_thin_device *td, dm_block_t *result)
1604{
1605    int r = -EINVAL;
1606    struct dm_pool_metadata *pmd = td->pmd;
1607
1608    down_read(&pmd->root_lock);
1609    if (!pmd->fail_io) {
1610        *result = td->mapped_blocks;
1611        r = 0;
1612    }
1613    up_read(&pmd->root_lock);
1614
1615    return r;
1616}
1617
1618static int __highest_block(struct dm_thin_device *td, dm_block_t *result)
1619{
1620    int r;
1621    __le64 value_le;
1622    dm_block_t thin_root;
1623    struct dm_pool_metadata *pmd = td->pmd;
1624
1625    r = dm_btree_lookup(&pmd->tl_info, pmd->root, &td->id, &value_le);
1626    if (r)
1627        return r;
1628
1629    thin_root = le64_to_cpu(value_le);
1630
1631    return dm_btree_find_highest_key(&pmd->bl_info, thin_root, result);
1632}
1633
1634int dm_thin_get_highest_mapped_block(struct dm_thin_device *td,
1635                     dm_block_t *result)
1636{
1637    int r = -EINVAL;
1638    struct dm_pool_metadata *pmd = td->pmd;
1639
1640    down_read(&pmd->root_lock);
1641    if (!pmd->fail_io)
1642        r = __highest_block(td, result);
1643    up_read(&pmd->root_lock);
1644
1645    return r;
1646}
1647
1648static int __resize_data_dev(struct dm_pool_metadata *pmd, dm_block_t new_count)
1649{
1650    int r;
1651    dm_block_t old_count;
1652
1653    r = dm_sm_get_nr_blocks(pmd->data_sm, &old_count);
1654    if (r)
1655        return r;
1656
1657    if (new_count == old_count)
1658        return 0;
1659
1660    if (new_count < old_count) {
1661        DMERR("cannot reduce size of data device");
1662        return -EINVAL;
1663    }
1664
1665    return dm_sm_extend(pmd->data_sm, new_count - old_count);
1666}
1667
1668int dm_pool_resize_data_dev(struct dm_pool_metadata *pmd, dm_block_t new_count)
1669{
1670    int r = -EINVAL;
1671
1672    down_write(&pmd->root_lock);
1673    if (!pmd->fail_io)
1674        r = __resize_data_dev(pmd, new_count);
1675    up_write(&pmd->root_lock);
1676
1677    return r;
1678}
1679
1680void dm_pool_metadata_read_only(struct dm_pool_metadata *pmd)
1681{
1682    down_write(&pmd->root_lock);
1683    pmd->read_only = true;
1684    dm_bm_set_read_only(pmd->bm);
1685    up_write(&pmd->root_lock);
1686}
1687

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