pandora: defconfig: update
[pandora-kernel.git] / 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("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("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("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("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
228         return 0;
229 }
230
231 int sm_ll_extend(struct ll_disk *ll, dm_block_t extra_blocks)
232 {
233         int r;
234         dm_block_t i, nr_blocks, nr_indexes;
235         unsigned old_blocks, blocks;
236
237         nr_blocks = ll->nr_blocks + extra_blocks;
238         old_blocks = dm_sector_div_up(ll->nr_blocks, ll->entries_per_block);
239         blocks = dm_sector_div_up(nr_blocks, ll->entries_per_block);
240
241         nr_indexes = dm_sector_div_up(nr_blocks, ll->entries_per_block);
242         if (nr_indexes > ll->max_entries(ll)) {
243                 DMERR("space map too large");
244                 return -EINVAL;
245         }
246
247         /*
248          * We need to set this before the dm_tm_new_block() call below.
249          */
250         ll->nr_blocks = nr_blocks;
251         for (i = old_blocks; i < blocks; i++) {
252                 struct dm_block *b;
253                 struct disk_index_entry idx;
254
255                 r = dm_tm_new_block(ll->tm, &dm_sm_bitmap_validator, &b);
256                 if (r < 0)
257                         return r;
258
259                 idx.blocknr = cpu_to_le64(dm_block_location(b));
260
261                 r = dm_tm_unlock(ll->tm, b);
262                 if (r < 0)
263                         return r;
264
265                 idx.nr_free = cpu_to_le32(ll->entries_per_block);
266                 idx.none_free_before = 0;
267
268                 r = ll->save_ie(ll, i, &idx);
269                 if (r < 0)
270                         return r;
271         }
272
273         return 0;
274 }
275
276 int sm_ll_lookup_bitmap(struct ll_disk *ll, dm_block_t b, uint32_t *result)
277 {
278         int r;
279         dm_block_t index = b;
280         struct disk_index_entry ie_disk;
281         struct dm_block *blk;
282
283         b = do_div(index, ll->entries_per_block);
284         r = ll->load_ie(ll, index, &ie_disk);
285         if (r < 0)
286                 return r;
287
288         r = dm_tm_read_lock(ll->tm, le64_to_cpu(ie_disk.blocknr),
289                             &dm_sm_bitmap_validator, &blk);
290         if (r < 0)
291                 return r;
292
293         *result = sm_lookup_bitmap(dm_bitmap_data(blk), b);
294
295         return dm_tm_unlock(ll->tm, blk);
296 }
297
298 int sm_ll_lookup(struct ll_disk *ll, dm_block_t b, uint32_t *result)
299 {
300         __le32 le_rc;
301         int r = sm_ll_lookup_bitmap(ll, b, result);
302
303         if (r)
304                 return r;
305
306         if (*result != 3)
307                 return r;
308
309         r = dm_btree_lookup(&ll->ref_count_info, ll->ref_count_root, &b, &le_rc);
310         if (r < 0)
311                 return r;
312
313         *result = le32_to_cpu(le_rc);
314
315         return r;
316 }
317
318 int sm_ll_find_free_block(struct ll_disk *ll, dm_block_t begin,
319                           dm_block_t end, dm_block_t *result)
320 {
321         int r;
322         struct disk_index_entry ie_disk;
323         dm_block_t i, index_begin = begin;
324         dm_block_t index_end = dm_sector_div_up(end, ll->entries_per_block);
325
326         /*
327          * FIXME: Use shifts
328          */
329         begin = do_div(index_begin, ll->entries_per_block);
330         end = do_div(end, ll->entries_per_block);
331
332         for (i = index_begin; i < index_end; i++, begin = 0) {
333                 struct dm_block *blk;
334                 unsigned position;
335                 uint32_t bit_end;
336
337                 r = ll->load_ie(ll, i, &ie_disk);
338                 if (r < 0)
339                         return r;
340
341                 if (le32_to_cpu(ie_disk.nr_free) == 0)
342                         continue;
343
344                 r = dm_tm_read_lock(ll->tm, le64_to_cpu(ie_disk.blocknr),
345                                     &dm_sm_bitmap_validator, &blk);
346                 if (r < 0)
347                         return r;
348
349                 bit_end = (i == index_end - 1) ?  end : ll->entries_per_block;
350
351                 r = sm_find_free(dm_bitmap_data(blk),
352                                  max_t(unsigned, begin, le32_to_cpu(ie_disk.none_free_before)),
353                                  bit_end, &position);
354                 if (r == -ENOSPC) {
355                         /*
356                          * This might happen because we started searching
357                          * part way through the bitmap.
358                          */
359                         dm_tm_unlock(ll->tm, blk);
360                         continue;
361
362                 } else if (r < 0) {
363                         dm_tm_unlock(ll->tm, blk);
364                         return r;
365                 }
366
367                 r = dm_tm_unlock(ll->tm, blk);
368                 if (r < 0)
369                         return r;
370
371                 *result = i * ll->entries_per_block + (dm_block_t) position;
372                 return 0;
373         }
374
375         return -ENOSPC;
376 }
377
378 int sm_ll_insert(struct ll_disk *ll, dm_block_t b,
379                  uint32_t ref_count, enum allocation_event *ev)
380 {
381         int r;
382         uint32_t bit, old;
383         struct dm_block *nb;
384         dm_block_t index = b;
385         struct disk_index_entry ie_disk;
386         void *bm_le;
387         int inc;
388
389         bit = do_div(index, ll->entries_per_block);
390         r = ll->load_ie(ll, index, &ie_disk);
391         if (r < 0)
392                 return r;
393
394         r = dm_tm_shadow_block(ll->tm, le64_to_cpu(ie_disk.blocknr),
395                                &dm_sm_bitmap_validator, &nb, &inc);
396         if (r < 0) {
397                 DMERR("dm_tm_shadow_block() failed");
398                 return r;
399         }
400         ie_disk.blocknr = cpu_to_le64(dm_block_location(nb));
401
402         bm_le = dm_bitmap_data(nb);
403         old = sm_lookup_bitmap(bm_le, bit);
404
405         if (ref_count <= 2) {
406                 sm_set_bitmap(bm_le, bit, ref_count);
407
408                 r = dm_tm_unlock(ll->tm, nb);
409                 if (r < 0)
410                         return r;
411
412 #if 0
413                 /* FIXME: dm_btree_remove doesn't handle this yet */
414                 if (old > 2) {
415                         r = dm_btree_remove(&ll->ref_count_info,
416                                             ll->ref_count_root,
417                                             &b, &ll->ref_count_root);
418                         if (r)
419                                 return r;
420                 }
421 #endif
422
423         } else {
424                 __le32 le_rc = cpu_to_le32(ref_count);
425
426                 sm_set_bitmap(bm_le, bit, 3);
427                 r = dm_tm_unlock(ll->tm, nb);
428                 if (r < 0)
429                         return r;
430
431                 __dm_bless_for_disk(&le_rc);
432                 r = dm_btree_insert(&ll->ref_count_info, ll->ref_count_root,
433                                     &b, &le_rc, &ll->ref_count_root);
434                 if (r < 0) {
435                         DMERR("ref count insert failed");
436                         return r;
437                 }
438         }
439
440         if (ref_count && !old) {
441                 *ev = SM_ALLOC;
442                 ll->nr_allocated++;
443                 ie_disk.nr_free = cpu_to_le32(le32_to_cpu(ie_disk.nr_free) - 1);
444                 if (le32_to_cpu(ie_disk.none_free_before) == bit)
445                         ie_disk.none_free_before = cpu_to_le32(bit + 1);
446
447         } else if (old && !ref_count) {
448                 *ev = SM_FREE;
449                 ll->nr_allocated--;
450                 ie_disk.nr_free = cpu_to_le32(le32_to_cpu(ie_disk.nr_free) + 1);
451                 ie_disk.none_free_before = cpu_to_le32(min(le32_to_cpu(ie_disk.none_free_before), bit));
452         }
453
454         return ll->save_ie(ll, index, &ie_disk);
455 }
456
457 int sm_ll_inc(struct ll_disk *ll, dm_block_t b, enum allocation_event *ev)
458 {
459         int r;
460         uint32_t rc;
461
462         r = sm_ll_lookup(ll, b, &rc);
463         if (r)
464                 return r;
465
466         return sm_ll_insert(ll, b, rc + 1, ev);
467 }
468
469 int sm_ll_dec(struct ll_disk *ll, dm_block_t b, enum allocation_event *ev)
470 {
471         int r;
472         uint32_t rc;
473
474         r = sm_ll_lookup(ll, b, &rc);
475         if (r)
476                 return r;
477
478         if (!rc)
479                 return -EINVAL;
480
481         return sm_ll_insert(ll, b, rc - 1, ev);
482 }
483
484 int sm_ll_commit(struct ll_disk *ll)
485 {
486         return ll->commit(ll);
487 }
488
489 /*----------------------------------------------------------------*/
490
491 static int metadata_ll_load_ie(struct ll_disk *ll, dm_block_t index,
492                                struct disk_index_entry *ie)
493 {
494         memcpy(ie, ll->mi_le.index + index, sizeof(*ie));
495         return 0;
496 }
497
498 static int metadata_ll_save_ie(struct ll_disk *ll, dm_block_t index,
499                                struct disk_index_entry *ie)
500 {
501         memcpy(ll->mi_le.index + index, ie, sizeof(*ie));
502         return 0;
503 }
504
505 static int metadata_ll_init_index(struct ll_disk *ll)
506 {
507         int r;
508         struct dm_block *b;
509
510         r = dm_tm_new_block(ll->tm, &index_validator, &b);
511         if (r < 0)
512                 return r;
513
514         memcpy(dm_block_data(b), &ll->mi_le, sizeof(ll->mi_le));
515         ll->bitmap_root = dm_block_location(b);
516
517         return dm_tm_unlock(ll->tm, b);
518 }
519
520 static int metadata_ll_open(struct ll_disk *ll)
521 {
522         int r;
523         struct dm_block *block;
524
525         r = dm_tm_read_lock(ll->tm, ll->bitmap_root,
526                             &index_validator, &block);
527         if (r)
528                 return r;
529
530         memcpy(&ll->mi_le, dm_block_data(block), sizeof(ll->mi_le));
531         return dm_tm_unlock(ll->tm, block);
532 }
533
534 static dm_block_t metadata_ll_max_entries(struct ll_disk *ll)
535 {
536         return MAX_METADATA_BITMAPS;
537 }
538
539 static int metadata_ll_commit(struct ll_disk *ll)
540 {
541         int r, inc;
542         struct dm_block *b;
543
544         r = dm_tm_shadow_block(ll->tm, ll->bitmap_root, &index_validator, &b, &inc);
545         if (r)
546                 return r;
547
548         memcpy(dm_block_data(b), &ll->mi_le, sizeof(ll->mi_le));
549         ll->bitmap_root = dm_block_location(b);
550
551         return dm_tm_unlock(ll->tm, b);
552 }
553
554 int sm_ll_new_metadata(struct ll_disk *ll, struct dm_transaction_manager *tm)
555 {
556         int r;
557
558         r = sm_ll_init(ll, tm);
559         if (r < 0)
560                 return r;
561
562         ll->load_ie = metadata_ll_load_ie;
563         ll->save_ie = metadata_ll_save_ie;
564         ll->init_index = metadata_ll_init_index;
565         ll->open_index = metadata_ll_open;
566         ll->max_entries = metadata_ll_max_entries;
567         ll->commit = metadata_ll_commit;
568
569         ll->nr_blocks = 0;
570         ll->nr_allocated = 0;
571
572         r = ll->init_index(ll);
573         if (r < 0)
574                 return r;
575
576         r = dm_btree_empty(&ll->ref_count_info, &ll->ref_count_root);
577         if (r < 0)
578                 return r;
579
580         return 0;
581 }
582
583 int sm_ll_open_metadata(struct ll_disk *ll, struct dm_transaction_manager *tm,
584                         void *root_le, size_t len)
585 {
586         int r;
587         struct disk_sm_root *smr = root_le;
588
589         if (len < sizeof(struct disk_sm_root)) {
590                 DMERR("sm_metadata root too small");
591                 return -ENOMEM;
592         }
593
594         r = sm_ll_init(ll, tm);
595         if (r < 0)
596                 return r;
597
598         ll->load_ie = metadata_ll_load_ie;
599         ll->save_ie = metadata_ll_save_ie;
600         ll->init_index = metadata_ll_init_index;
601         ll->open_index = metadata_ll_open;
602         ll->max_entries = metadata_ll_max_entries;
603         ll->commit = metadata_ll_commit;
604
605         ll->nr_blocks = le64_to_cpu(smr->nr_blocks);
606         ll->nr_allocated = le64_to_cpu(smr->nr_allocated);
607         ll->bitmap_root = le64_to_cpu(smr->bitmap_root);
608         ll->ref_count_root = le64_to_cpu(smr->ref_count_root);
609
610         return ll->open_index(ll);
611 }
612
613 /*----------------------------------------------------------------*/
614
615 static int disk_ll_load_ie(struct ll_disk *ll, dm_block_t index,
616                            struct disk_index_entry *ie)
617 {
618         return dm_btree_lookup(&ll->bitmap_info, ll->bitmap_root, &index, ie);
619 }
620
621 static int disk_ll_save_ie(struct ll_disk *ll, dm_block_t index,
622                            struct disk_index_entry *ie)
623 {
624         __dm_bless_for_disk(ie);
625         return dm_btree_insert(&ll->bitmap_info, ll->bitmap_root,
626                                &index, ie, &ll->bitmap_root);
627 }
628
629 static int disk_ll_init_index(struct ll_disk *ll)
630 {
631         return dm_btree_empty(&ll->bitmap_info, &ll->bitmap_root);
632 }
633
634 static int disk_ll_open(struct ll_disk *ll)
635 {
636         /* nothing to do */
637         return 0;
638 }
639
640 static dm_block_t disk_ll_max_entries(struct ll_disk *ll)
641 {
642         return -1ULL;
643 }
644
645 static int disk_ll_commit(struct ll_disk *ll)
646 {
647         return 0;
648 }
649
650 int sm_ll_new_disk(struct ll_disk *ll, struct dm_transaction_manager *tm)
651 {
652         int r;
653
654         r = sm_ll_init(ll, tm);
655         if (r < 0)
656                 return r;
657
658         ll->load_ie = disk_ll_load_ie;
659         ll->save_ie = disk_ll_save_ie;
660         ll->init_index = disk_ll_init_index;
661         ll->open_index = disk_ll_open;
662         ll->max_entries = disk_ll_max_entries;
663         ll->commit = disk_ll_commit;
664
665         ll->nr_blocks = 0;
666         ll->nr_allocated = 0;
667
668         r = ll->init_index(ll);
669         if (r < 0)
670                 return r;
671
672         r = dm_btree_empty(&ll->ref_count_info, &ll->ref_count_root);
673         if (r < 0)
674                 return r;
675
676         return 0;
677 }
678
679 int sm_ll_open_disk(struct ll_disk *ll, struct dm_transaction_manager *tm,
680                     void *root_le, size_t len)
681 {
682         int r;
683         struct disk_sm_root *smr = root_le;
684
685         if (len < sizeof(struct disk_sm_root)) {
686                 DMERR("sm_metadata root too small");
687                 return -ENOMEM;
688         }
689
690         r = sm_ll_init(ll, tm);
691         if (r < 0)
692                 return r;
693
694         ll->load_ie = disk_ll_load_ie;
695         ll->save_ie = disk_ll_save_ie;
696         ll->init_index = disk_ll_init_index;
697         ll->open_index = disk_ll_open;
698         ll->max_entries = disk_ll_max_entries;
699         ll->commit = disk_ll_commit;
700
701         ll->nr_blocks = le64_to_cpu(smr->nr_blocks);
702         ll->nr_allocated = le64_to_cpu(smr->nr_allocated);
703         ll->bitmap_root = le64_to_cpu(smr->bitmap_root);
704         ll->ref_count_root = le64_to_cpu(smr->ref_count_root);
705
706         return ll->open_index(ll);
707 }
708
709 /*----------------------------------------------------------------*/