Add the rt linux 4.1.3-rt3 as base
[kvmfornfv.git] / kernel / drivers / md / persistent-data / dm-space-map-common.c
1 /*
2  * Copyright (C) 2011 Red Hat, Inc.
3  *
4  * This file is released under the GPL.
5  */
6
7 #include "dm-space-map-common.h"
8 #include "dm-transaction-manager.h"
9
10 #include <linux/bitops.h>
11 #include <linux/device-mapper.h>
12
13 #define DM_MSG_PREFIX "space map common"
14
15 /*----------------------------------------------------------------*/
16
17 /*
18  * Index validator.
19  */
20 #define INDEX_CSUM_XOR 160478
21
22 static void index_prepare_for_write(struct dm_block_validator *v,
23                                     struct dm_block *b,
24                                     size_t block_size)
25 {
26         struct disk_metadata_index *mi_le = dm_block_data(b);
27
28         mi_le->blocknr = cpu_to_le64(dm_block_location(b));
29         mi_le->csum = cpu_to_le32(dm_bm_checksum(&mi_le->padding,
30                                                  block_size - sizeof(__le32),
31                                                  INDEX_CSUM_XOR));
32 }
33
34 static int index_check(struct dm_block_validator *v,
35                        struct dm_block *b,
36                        size_t block_size)
37 {
38         struct disk_metadata_index *mi_le = dm_block_data(b);
39         __le32 csum_disk;
40
41         if (dm_block_location(b) != le64_to_cpu(mi_le->blocknr)) {
42                 DMERR_LIMIT("index_check failed: blocknr %llu != wanted %llu",
43                             le64_to_cpu(mi_le->blocknr), dm_block_location(b));
44                 return -ENOTBLK;
45         }
46
47         csum_disk = cpu_to_le32(dm_bm_checksum(&mi_le->padding,
48                                                block_size - sizeof(__le32),
49                                                INDEX_CSUM_XOR));
50         if (csum_disk != mi_le->csum) {
51                 DMERR_LIMIT("index_check failed: csum %u != wanted %u",
52                             le32_to_cpu(csum_disk), le32_to_cpu(mi_le->csum));
53                 return -EILSEQ;
54         }
55
56         return 0;
57 }
58
59 static struct dm_block_validator index_validator = {
60         .name = "index",
61         .prepare_for_write = index_prepare_for_write,
62         .check = index_check
63 };
64
65 /*----------------------------------------------------------------*/
66
67 /*
68  * Bitmap validator
69  */
70 #define BITMAP_CSUM_XOR 240779
71
72 static void bitmap_prepare_for_write(struct dm_block_validator *v,
73                                      struct dm_block *b,
74                                      size_t block_size)
75 {
76         struct disk_bitmap_header *disk_header = dm_block_data(b);
77
78         disk_header->blocknr = cpu_to_le64(dm_block_location(b));
79         disk_header->csum = cpu_to_le32(dm_bm_checksum(&disk_header->not_used,
80                                                        block_size - sizeof(__le32),
81                                                        BITMAP_CSUM_XOR));
82 }
83
84 static int bitmap_check(struct dm_block_validator *v,
85                         struct dm_block *b,
86                         size_t block_size)
87 {
88         struct disk_bitmap_header *disk_header = dm_block_data(b);
89         __le32 csum_disk;
90
91         if (dm_block_location(b) != le64_to_cpu(disk_header->blocknr)) {
92                 DMERR_LIMIT("bitmap check failed: blocknr %llu != wanted %llu",
93                             le64_to_cpu(disk_header->blocknr), dm_block_location(b));
94                 return -ENOTBLK;
95         }
96
97         csum_disk = cpu_to_le32(dm_bm_checksum(&disk_header->not_used,
98                                                block_size - sizeof(__le32),
99                                                BITMAP_CSUM_XOR));
100         if (csum_disk != disk_header->csum) {
101                 DMERR_LIMIT("bitmap check failed: csum %u != wanted %u",
102                             le32_to_cpu(csum_disk), le32_to_cpu(disk_header->csum));
103                 return -EILSEQ;
104         }
105
106         return 0;
107 }
108
109 static struct dm_block_validator dm_sm_bitmap_validator = {
110         .name = "sm_bitmap",
111         .prepare_for_write = bitmap_prepare_for_write,
112         .check = bitmap_check
113 };
114
115 /*----------------------------------------------------------------*/
116
117 #define ENTRIES_PER_WORD 32
118 #define ENTRIES_SHIFT   5
119
120 static void *dm_bitmap_data(struct dm_block *b)
121 {
122         return dm_block_data(b) + sizeof(struct disk_bitmap_header);
123 }
124
125 #define WORD_MASK_HIGH 0xAAAAAAAAAAAAAAAAULL
126
127 static unsigned bitmap_word_used(void *addr, unsigned b)
128 {
129         __le64 *words_le = addr;
130         __le64 *w_le = words_le + (b >> ENTRIES_SHIFT);
131
132         uint64_t bits = le64_to_cpu(*w_le);
133         uint64_t mask = (bits + WORD_MASK_HIGH + 1) & WORD_MASK_HIGH;
134
135         return !(~bits & mask);
136 }
137
138 static unsigned sm_lookup_bitmap(void *addr, unsigned b)
139 {
140         __le64 *words_le = addr;
141         __le64 *w_le = words_le + (b >> ENTRIES_SHIFT);
142         unsigned hi, lo;
143
144         b = (b & (ENTRIES_PER_WORD - 1)) << 1;
145         hi = !!test_bit_le(b, (void *) w_le);
146         lo = !!test_bit_le(b + 1, (void *) w_le);
147         return (hi << 1) | lo;
148 }
149
150 static void sm_set_bitmap(void *addr, unsigned b, unsigned val)
151 {
152         __le64 *words_le = addr;
153         __le64 *w_le = words_le + (b >> ENTRIES_SHIFT);
154
155         b = (b & (ENTRIES_PER_WORD - 1)) << 1;
156
157         if (val & 2)
158                 __set_bit_le(b, (void *) w_le);
159         else
160                 __clear_bit_le(b, (void *) w_le);
161
162         if (val & 1)
163                 __set_bit_le(b + 1, (void *) w_le);
164         else
165                 __clear_bit_le(b + 1, (void *) w_le);
166 }
167
168 static int sm_find_free(void *addr, unsigned begin, unsigned end,
169                         unsigned *result)
170 {
171         while (begin < end) {
172                 if (!(begin & (ENTRIES_PER_WORD - 1)) &&
173                     bitmap_word_used(addr, begin)) {
174                         begin += ENTRIES_PER_WORD;
175                         continue;
176                 }
177
178                 if (!sm_lookup_bitmap(addr, begin)) {
179                         *result = begin;
180                         return 0;
181                 }
182
183                 begin++;
184         }
185
186         return -ENOSPC;
187 }
188
189 /*----------------------------------------------------------------*/
190
191 static int sm_ll_init(struct ll_disk *ll, struct dm_transaction_manager *tm)
192 {
193         ll->tm = tm;
194
195         ll->bitmap_info.tm = tm;
196         ll->bitmap_info.levels = 1;
197
198         /*
199          * Because the new bitmap blocks are created via a shadow
200          * operation, the old entry has already had its reference count
201          * decremented and we don't need the btree to do any bookkeeping.
202          */
203         ll->bitmap_info.value_type.size = sizeof(struct disk_index_entry);
204         ll->bitmap_info.value_type.inc = NULL;
205         ll->bitmap_info.value_type.dec = NULL;
206         ll->bitmap_info.value_type.equal = NULL;
207
208         ll->ref_count_info.tm = tm;
209         ll->ref_count_info.levels = 1;
210         ll->ref_count_info.value_type.size = sizeof(uint32_t);
211         ll->ref_count_info.value_type.inc = NULL;
212         ll->ref_count_info.value_type.dec = NULL;
213         ll->ref_count_info.value_type.equal = NULL;
214
215         ll->block_size = dm_bm_block_size(dm_tm_get_bm(tm));
216
217         if (ll->block_size > (1 << 30)) {
218                 DMERR("block size too big to hold bitmaps");
219                 return -EINVAL;
220         }
221
222         ll->entries_per_block = (ll->block_size - sizeof(struct disk_bitmap_header)) *
223                 ENTRIES_PER_BYTE;
224         ll->nr_blocks = 0;
225         ll->bitmap_root = 0;
226         ll->ref_count_root = 0;
227         ll->bitmap_index_changed = false;
228
229         return 0;
230 }
231
232 int sm_ll_extend(struct ll_disk *ll, dm_block_t extra_blocks)
233 {
234         int r;
235         dm_block_t i, nr_blocks, nr_indexes;
236         unsigned old_blocks, blocks;
237
238         nr_blocks = ll->nr_blocks + extra_blocks;
239         old_blocks = dm_sector_div_up(ll->nr_blocks, ll->entries_per_block);
240         blocks = dm_sector_div_up(nr_blocks, ll->entries_per_block);
241
242         nr_indexes = dm_sector_div_up(nr_blocks, ll->entries_per_block);
243         if (nr_indexes > ll->max_entries(ll)) {
244                 DMERR("space map too large");
245                 return -EINVAL;
246         }
247
248         /*
249          * We need to set this before the dm_tm_new_block() call below.
250          */
251         ll->nr_blocks = nr_blocks;
252         for (i = old_blocks; i < blocks; i++) {
253                 struct dm_block *b;
254                 struct disk_index_entry idx;
255
256                 r = dm_tm_new_block(ll->tm, &dm_sm_bitmap_validator, &b);
257                 if (r < 0)
258                         return r;
259
260                 idx.blocknr = cpu_to_le64(dm_block_location(b));
261
262                 r = dm_tm_unlock(ll->tm, b);
263                 if (r < 0)
264                         return r;
265
266                 idx.nr_free = cpu_to_le32(ll->entries_per_block);
267                 idx.none_free_before = 0;
268
269                 r = ll->save_ie(ll, i, &idx);
270                 if (r < 0)
271                         return r;
272         }
273
274         return 0;
275 }
276
277 int sm_ll_lookup_bitmap(struct ll_disk *ll, dm_block_t b, uint32_t *result)
278 {
279         int r;
280         dm_block_t index = b;
281         struct disk_index_entry ie_disk;
282         struct dm_block *blk;
283
284         b = do_div(index, ll->entries_per_block);
285         r = ll->load_ie(ll, index, &ie_disk);
286         if (r < 0)
287                 return r;
288
289         r = dm_tm_read_lock(ll->tm, le64_to_cpu(ie_disk.blocknr),
290                             &dm_sm_bitmap_validator, &blk);
291         if (r < 0)
292                 return r;
293
294         *result = sm_lookup_bitmap(dm_bitmap_data(blk), b);
295
296         return dm_tm_unlock(ll->tm, blk);
297 }
298
299 static int sm_ll_lookup_big_ref_count(struct ll_disk *ll, dm_block_t b,
300                                       uint32_t *result)
301 {
302         __le32 le_rc;
303         int r;
304
305         r = dm_btree_lookup(&ll->ref_count_info, ll->ref_count_root, &b, &le_rc);
306         if (r < 0)
307                 return r;
308
309         *result = le32_to_cpu(le_rc);
310
311         return r;
312 }
313
314 int sm_ll_lookup(struct ll_disk *ll, dm_block_t b, uint32_t *result)
315 {
316         int r = sm_ll_lookup_bitmap(ll, b, result);
317
318         if (r)
319                 return r;
320
321         if (*result != 3)
322                 return r;
323
324         return sm_ll_lookup_big_ref_count(ll, b, result);
325 }
326
327 int sm_ll_find_free_block(struct ll_disk *ll, dm_block_t begin,
328                           dm_block_t end, dm_block_t *result)
329 {
330         int r;
331         struct disk_index_entry ie_disk;
332         dm_block_t i, index_begin = begin;
333         dm_block_t index_end = dm_sector_div_up(end, ll->entries_per_block);
334
335         /*
336          * FIXME: Use shifts
337          */
338         begin = do_div(index_begin, ll->entries_per_block);
339         end = do_div(end, ll->entries_per_block);
340
341         for (i = index_begin; i < index_end; i++, begin = 0) {
342                 struct dm_block *blk;
343                 unsigned position;
344                 uint32_t bit_end;
345
346                 r = ll->load_ie(ll, i, &ie_disk);
347                 if (r < 0)
348                         return r;
349
350                 if (le32_to_cpu(ie_disk.nr_free) == 0)
351                         continue;
352
353                 r = dm_tm_read_lock(ll->tm, le64_to_cpu(ie_disk.blocknr),
354                                     &dm_sm_bitmap_validator, &blk);
355                 if (r < 0)
356                         return r;
357
358                 bit_end = (i == index_end - 1) ?  end : ll->entries_per_block;
359
360                 r = sm_find_free(dm_bitmap_data(blk),
361                                  max_t(unsigned, begin, le32_to_cpu(ie_disk.none_free_before)),
362                                  bit_end, &position);
363                 if (r == -ENOSPC) {
364                         /*
365                          * This might happen because we started searching
366                          * part way through the bitmap.
367                          */
368                         dm_tm_unlock(ll->tm, blk);
369                         continue;
370
371                 } else if (r < 0) {
372                         dm_tm_unlock(ll->tm, blk);
373                         return r;
374                 }
375
376                 r = dm_tm_unlock(ll->tm, blk);
377                 if (r < 0)
378                         return r;
379
380                 *result = i * ll->entries_per_block + (dm_block_t) position;
381                 return 0;
382         }
383
384         return -ENOSPC;
385 }
386
387 static int sm_ll_mutate(struct ll_disk *ll, dm_block_t b,
388                         int (*mutator)(void *context, uint32_t old, uint32_t *new),
389                         void *context, enum allocation_event *ev)
390 {
391         int r;
392         uint32_t bit, old, ref_count;
393         struct dm_block *nb;
394         dm_block_t index = b;
395         struct disk_index_entry ie_disk;
396         void *bm_le;
397         int inc;
398
399         bit = do_div(index, ll->entries_per_block);
400         r = ll->load_ie(ll, index, &ie_disk);
401         if (r < 0)
402                 return r;
403
404         r = dm_tm_shadow_block(ll->tm, le64_to_cpu(ie_disk.blocknr),
405                                &dm_sm_bitmap_validator, &nb, &inc);
406         if (r < 0) {
407                 DMERR("dm_tm_shadow_block() failed");
408                 return r;
409         }
410         ie_disk.blocknr = cpu_to_le64(dm_block_location(nb));
411
412         bm_le = dm_bitmap_data(nb);
413         old = sm_lookup_bitmap(bm_le, bit);
414
415         if (old > 2) {
416                 r = sm_ll_lookup_big_ref_count(ll, b, &old);
417                 if (r < 0) {
418                         dm_tm_unlock(ll->tm, nb);
419                         return r;
420                 }
421         }
422
423         r = mutator(context, old, &ref_count);
424         if (r) {
425                 dm_tm_unlock(ll->tm, nb);
426                 return r;
427         }
428
429         if (ref_count <= 2) {
430                 sm_set_bitmap(bm_le, bit, ref_count);
431
432                 r = dm_tm_unlock(ll->tm, nb);
433                 if (r < 0)
434                         return r;
435
436                 if (old > 2) {
437                         r = dm_btree_remove(&ll->ref_count_info,
438                                             ll->ref_count_root,
439                                             &b, &ll->ref_count_root);
440                         if (r)
441                                 return r;
442                 }
443
444         } else {
445                 __le32 le_rc = cpu_to_le32(ref_count);
446
447                 sm_set_bitmap(bm_le, bit, 3);
448                 r = dm_tm_unlock(ll->tm, nb);
449                 if (r < 0)
450                         return r;
451
452                 __dm_bless_for_disk(&le_rc);
453                 r = dm_btree_insert(&ll->ref_count_info, ll->ref_count_root,
454                                     &b, &le_rc, &ll->ref_count_root);
455                 if (r < 0) {
456                         DMERR("ref count insert failed");
457                         return r;
458                 }
459         }
460
461         if (ref_count && !old) {
462                 *ev = SM_ALLOC;
463                 ll->nr_allocated++;
464                 le32_add_cpu(&ie_disk.nr_free, -1);
465                 if (le32_to_cpu(ie_disk.none_free_before) == bit)
466                         ie_disk.none_free_before = cpu_to_le32(bit + 1);
467
468         } else if (old && !ref_count) {
469                 *ev = SM_FREE;
470                 ll->nr_allocated--;
471                 le32_add_cpu(&ie_disk.nr_free, 1);
472                 ie_disk.none_free_before = cpu_to_le32(min(le32_to_cpu(ie_disk.none_free_before), bit));
473         }
474
475         return ll->save_ie(ll, index, &ie_disk);
476 }
477
478 static int set_ref_count(void *context, uint32_t old, uint32_t *new)
479 {
480         *new = *((uint32_t *) context);
481         return 0;
482 }
483
484 int sm_ll_insert(struct ll_disk *ll, dm_block_t b,
485                  uint32_t ref_count, enum allocation_event *ev)
486 {
487         return sm_ll_mutate(ll, b, set_ref_count, &ref_count, ev);
488 }
489
490 static int inc_ref_count(void *context, uint32_t old, uint32_t *new)
491 {
492         *new = old + 1;
493         return 0;
494 }
495
496 int sm_ll_inc(struct ll_disk *ll, dm_block_t b, enum allocation_event *ev)
497 {
498         return sm_ll_mutate(ll, b, inc_ref_count, NULL, ev);
499 }
500
501 static int dec_ref_count(void *context, uint32_t old, uint32_t *new)
502 {
503         if (!old) {
504                 DMERR_LIMIT("unable to decrement a reference count below 0");
505                 return -EINVAL;
506         }
507
508         *new = old - 1;
509         return 0;
510 }
511
512 int sm_ll_dec(struct ll_disk *ll, dm_block_t b, enum allocation_event *ev)
513 {
514         return sm_ll_mutate(ll, b, dec_ref_count, NULL, ev);
515 }
516
517 int sm_ll_commit(struct ll_disk *ll)
518 {
519         int r = 0;
520
521         if (ll->bitmap_index_changed) {
522                 r = ll->commit(ll);
523                 if (!r)
524                         ll->bitmap_index_changed = false;
525         }
526
527         return r;
528 }
529
530 /*----------------------------------------------------------------*/
531
532 static int metadata_ll_load_ie(struct ll_disk *ll, dm_block_t index,
533                                struct disk_index_entry *ie)
534 {
535         memcpy(ie, ll->mi_le.index + index, sizeof(*ie));
536         return 0;
537 }
538
539 static int metadata_ll_save_ie(struct ll_disk *ll, dm_block_t index,
540                                struct disk_index_entry *ie)
541 {
542         ll->bitmap_index_changed = true;
543         memcpy(ll->mi_le.index + index, ie, sizeof(*ie));
544         return 0;
545 }
546
547 static int metadata_ll_init_index(struct ll_disk *ll)
548 {
549         int r;
550         struct dm_block *b;
551
552         r = dm_tm_new_block(ll->tm, &index_validator, &b);
553         if (r < 0)
554                 return r;
555
556         memcpy(dm_block_data(b), &ll->mi_le, sizeof(ll->mi_le));
557         ll->bitmap_root = dm_block_location(b);
558
559         return dm_tm_unlock(ll->tm, b);
560 }
561
562 static int metadata_ll_open(struct ll_disk *ll)
563 {
564         int r;
565         struct dm_block *block;
566
567         r = dm_tm_read_lock(ll->tm, ll->bitmap_root,
568                             &index_validator, &block);
569         if (r)
570                 return r;
571
572         memcpy(&ll->mi_le, dm_block_data(block), sizeof(ll->mi_le));
573         return dm_tm_unlock(ll->tm, block);
574 }
575
576 static dm_block_t metadata_ll_max_entries(struct ll_disk *ll)
577 {
578         return MAX_METADATA_BITMAPS;
579 }
580
581 static int metadata_ll_commit(struct ll_disk *ll)
582 {
583         int r, inc;
584         struct dm_block *b;
585
586         r = dm_tm_shadow_block(ll->tm, ll->bitmap_root, &index_validator, &b, &inc);
587         if (r)
588                 return r;
589
590         memcpy(dm_block_data(b), &ll->mi_le, sizeof(ll->mi_le));
591         ll->bitmap_root = dm_block_location(b);
592
593         return dm_tm_unlock(ll->tm, b);
594 }
595
596 int sm_ll_new_metadata(struct ll_disk *ll, struct dm_transaction_manager *tm)
597 {
598         int r;
599
600         r = sm_ll_init(ll, tm);
601         if (r < 0)
602                 return r;
603
604         ll->load_ie = metadata_ll_load_ie;
605         ll->save_ie = metadata_ll_save_ie;
606         ll->init_index = metadata_ll_init_index;
607         ll->open_index = metadata_ll_open;
608         ll->max_entries = metadata_ll_max_entries;
609         ll->commit = metadata_ll_commit;
610
611         ll->nr_blocks = 0;
612         ll->nr_allocated = 0;
613
614         r = ll->init_index(ll);
615         if (r < 0)
616                 return r;
617
618         r = dm_btree_empty(&ll->ref_count_info, &ll->ref_count_root);
619         if (r < 0)
620                 return r;
621
622         return 0;
623 }
624
625 int sm_ll_open_metadata(struct ll_disk *ll, struct dm_transaction_manager *tm,
626                         void *root_le, size_t len)
627 {
628         int r;
629         struct disk_sm_root *smr = root_le;
630
631         if (len < sizeof(struct disk_sm_root)) {
632                 DMERR("sm_metadata root too small");
633                 return -ENOMEM;
634         }
635
636         r = sm_ll_init(ll, tm);
637         if (r < 0)
638                 return r;
639
640         ll->load_ie = metadata_ll_load_ie;
641         ll->save_ie = metadata_ll_save_ie;
642         ll->init_index = metadata_ll_init_index;
643         ll->open_index = metadata_ll_open;
644         ll->max_entries = metadata_ll_max_entries;
645         ll->commit = metadata_ll_commit;
646
647         ll->nr_blocks = le64_to_cpu(smr->nr_blocks);
648         ll->nr_allocated = le64_to_cpu(smr->nr_allocated);
649         ll->bitmap_root = le64_to_cpu(smr->bitmap_root);
650         ll->ref_count_root = le64_to_cpu(smr->ref_count_root);
651
652         return ll->open_index(ll);
653 }
654
655 /*----------------------------------------------------------------*/
656
657 static int disk_ll_load_ie(struct ll_disk *ll, dm_block_t index,
658                            struct disk_index_entry *ie)
659 {
660         return dm_btree_lookup(&ll->bitmap_info, ll->bitmap_root, &index, ie);
661 }
662
663 static int disk_ll_save_ie(struct ll_disk *ll, dm_block_t index,
664                            struct disk_index_entry *ie)
665 {
666         __dm_bless_for_disk(ie);
667         return dm_btree_insert(&ll->bitmap_info, ll->bitmap_root,
668                                &index, ie, &ll->bitmap_root);
669 }
670
671 static int disk_ll_init_index(struct ll_disk *ll)
672 {
673         return dm_btree_empty(&ll->bitmap_info, &ll->bitmap_root);
674 }
675
676 static int disk_ll_open(struct ll_disk *ll)
677 {
678         /* nothing to do */
679         return 0;
680 }
681
682 static dm_block_t disk_ll_max_entries(struct ll_disk *ll)
683 {
684         return -1ULL;
685 }
686
687 static int disk_ll_commit(struct ll_disk *ll)
688 {
689         return 0;
690 }
691
692 int sm_ll_new_disk(struct ll_disk *ll, struct dm_transaction_manager *tm)
693 {
694         int r;
695
696         r = sm_ll_init(ll, tm);
697         if (r < 0)
698                 return r;
699
700         ll->load_ie = disk_ll_load_ie;
701         ll->save_ie = disk_ll_save_ie;
702         ll->init_index = disk_ll_init_index;
703         ll->open_index = disk_ll_open;
704         ll->max_entries = disk_ll_max_entries;
705         ll->commit = disk_ll_commit;
706
707         ll->nr_blocks = 0;
708         ll->nr_allocated = 0;
709
710         r = ll->init_index(ll);
711         if (r < 0)
712                 return r;
713
714         r = dm_btree_empty(&ll->ref_count_info, &ll->ref_count_root);
715         if (r < 0)
716                 return r;
717
718         return 0;
719 }
720
721 int sm_ll_open_disk(struct ll_disk *ll, struct dm_transaction_manager *tm,
722                     void *root_le, size_t len)
723 {
724         int r;
725         struct disk_sm_root *smr = root_le;
726
727         if (len < sizeof(struct disk_sm_root)) {
728                 DMERR("sm_metadata root too small");
729                 return -ENOMEM;
730         }
731
732         r = sm_ll_init(ll, tm);
733         if (r < 0)
734                 return r;
735
736         ll->load_ie = disk_ll_load_ie;
737         ll->save_ie = disk_ll_save_ie;
738         ll->init_index = disk_ll_init_index;
739         ll->open_index = disk_ll_open;
740         ll->max_entries = disk_ll_max_entries;
741         ll->commit = disk_ll_commit;
742
743         ll->nr_blocks = le64_to_cpu(smr->nr_blocks);
744         ll->nr_allocated = le64_to_cpu(smr->nr_allocated);
745         ll->bitmap_root = le64_to_cpu(smr->bitmap_root);
746         ll->ref_count_root = le64_to_cpu(smr->ref_count_root);
747
748         return ll->open_index(ll);
749 }
750
751 /*----------------------------------------------------------------*/