boot/freeldr/freeldr/lib/fs/btrfs.c

   1 /*
   2  * PROJECT:     FreeLoader
   3  * LICENSE:     GPL-2.0+ (https://spdx.org/licenses/GPL-2.0+)
   4  * PURPOSE:     BTRFS support for FreeLoader
   5  * COPYRIGHT:   Copyright 2018 Victor Perevertkin (victor@perevertkin.ru)
   6  */
   7
   8 /* Some code was taken from u-boot, https://github.com/u-boot/u-boot/tree/master/fs/btrfs */
   9
  10 #include <freeldr.h>
  11 #include <debug.h>
  12
  13 DBG_DEFAULT_CHANNEL(FILESYSTEM);
  14
  15 #define TAG_BTRFS_INFO 'IftB'
  16 #define TAG_BTRFS_CHUNK_MAP 'CftB'
  17 #define TAG_BTRFS_NODE  'NftB'
  18 #define TAG_BTRFS_FILE  'FftB'
  19 #define TAG_BTRFS_LINK  'LftB'
  20
  21 #define INVALID_INODE _UI64_MAX
  22 #define INVALID_ADDRESS _UI64_MAX
  23 #define READ_ERROR _UI64_MAX
  24
  25 struct BTRFS_INFO {
  26     ULONG DeviceId;
  27     struct btrfs_super_block SuperBlock;
  28     struct btrfs_chunk_map ChunkMap;
  29     struct btrfs_root_item FsRoot;
  30     struct btrfs_root_item ExtentRoot;
  31 };
  32
  33 struct BTRFS_INFO *BtrFsInfo;
  34
  35 /* compare function used for bin_search */
  36 typedef int (*cmp_func)(const void *ptr1, const void *ptr2);
  37
  38 /* simple but useful bin search, used for chunk search and btree search */
  39 static int bin_search(void *ptr, int item_size, void *cmp_item, cmp_func func,
  40                       int min, int max, int *slot)
  41 {
  42     int low = min;
  43     int high = max;
  44     int mid;
  45     int ret;
  46     unsigned long offset;
  47     UCHAR *item;
  48
  49     while (low < high)
  50     {
  51         mid = (low + high) / 2;
  52         offset = mid * item_size;
  53
  54         item = (UCHAR *) ptr + offset;
  55         ret = func((void *) item, cmp_item);
  56
  57         if (ret < 0)
  58         {
  59             low = mid + 1;
  60         }
  61         else if (ret > 0)
  62         {
  63             high = mid;
  64         }
  65         else
  66         {
  67             *slot = mid;
  68             return 0;
  69         }
  70     }
  71     *slot = low;
  72     return 1;
  73 }
  74
  75 static int btrfs_comp_chunk_map(struct btrfs_chunk_map_item *m1,
  76                                 struct btrfs_chunk_map_item *m2)
  77 {
  78     if (m1->logical > m2->logical)
  79         return 1;
  80     if (m1->logical < m2->logical)
  81         return -1;
  82     return 0;
  83 }
  84
  85 /* insert a new chunk mapping item */
  86 static void insert_chunk_item(struct btrfs_chunk_map_item *item)
  87 {
  88     struct btrfs_chunk_map *chunk_map = &BtrFsInfo->ChunkMap;
  89     int ret;
  90     int slot;
  91     int i;
  92
  93     if (chunk_map->map == NULL)
  94     {
  95         /* first item */
  96         chunk_map->map_length = BTRFS_MAX_CHUNK_ENTRIES;
  97         chunk_map->map = FrLdrTempAlloc(chunk_map->map_length * sizeof(chunk_map->map[0]), TAG_BTRFS_CHUNK_MAP);
  98         chunk_map->map[0] = *item;
  99         chunk_map->cur_length = 1;
 100         return;
 101     }
 102     ret = bin_search(chunk_map->map, sizeof(*item), item,
 103                      (cmp_func) btrfs_comp_chunk_map, 0,
 104                      chunk_map->cur_length, &slot);
 105     if (ret == 0)/* already in map */
 106         return;
 107
 108     if (chunk_map->cur_length == BTRFS_MAX_CHUNK_ENTRIES)
 109     {
 110         /* should be impossible */
 111         TRACE("too many chunk items\n");
 112         return;
 113     }
 114
 115     for (i = chunk_map->cur_length; i > slot; i--)
 116         chunk_map->map[i] = chunk_map->map[i - 1];
 117
 118     chunk_map->map[slot] = *item;
 119     chunk_map->cur_length++;
 120 }
 121
 122 static inline void insert_map(const struct btrfs_disk_key *key, struct btrfs_chunk *chunk)
 123 {
 124     struct btrfs_stripe *stripe = &chunk->stripe;
 125     struct btrfs_stripe *stripe_end = stripe + chunk->num_stripes;
 126     struct btrfs_chunk_map_item item;
 127
 128     item.logical = key->offset;
 129     item.length = chunk->length;
 130     for (; stripe < stripe_end; stripe++)
 131     {
 132         TRACE("stripe: %p\n", stripe);
 133         item.devid = stripe->devid;
 134         item.physical = stripe->offset;
 135         TRACE("inserting chunk log: %llx len: %llx devid: %llx phys: %llx\n", item.logical, item.length, item.devid,
 136               item.physical);
 137         insert_chunk_item(&item);
 138     }
 139
 140 #if 0
 141     struct btrfs_chunk_map *chunk_map = &BtrFsInfo->ChunkMap;
 142     struct btrfs_chunk_map_item *itm;
 143     int i;
 144
 145     TRACE("insert finished. Printing chunk map:\n------------------------------\n");
 146
 147     for (i = 0; i < chunk_map->cur_length; i++)
 148     {
 149         itm = &chunk_map->map[i];
 150         TRACE("%llx..%llx -> %llx..%llx, devid: %llu\n",
 151               itm->logical,
 152               itm->logical + itm->length,
 153               itm->physical,
 154               itm->physical + itm->length,
 155               itm->devid
 156         );
 157     }
 158 #endif
 159 }
 160
 161 static inline unsigned long btrfs_chunk_item_size(int num_stripes)
 162 {
 163     return sizeof(struct btrfs_chunk) +
 164            sizeof(struct btrfs_stripe) * (num_stripes - 1);
 165 }
 166
 167 static inline void init_path(struct btrfs_path *path)
 168 {
 169     memset(path, 0, sizeof(*path));
 170     path->tree_buf = FrLdrTempAlloc(BtrFsInfo->SuperBlock.nodesize, TAG_BTRFS_NODE);
 171 }
 172
 173 static inline void free_path(struct btrfs_path *path)
 174 {
 175     if (path->tree_buf) FrLdrTempFree(path->tree_buf, TAG_BTRFS_NODE);
 176 }
 177
 178 static inline struct btrfs_item *path_current_item(struct btrfs_path *path)
 179 {
 180     return &path->tree_buf->leaf.items[path->slots[0]];
 181 }
 182
 183 static inline UCHAR *path_current_data(struct btrfs_path *path)
 184 {
 185     return (UCHAR *) path->tree_buf->leaf.items + path_current_item(path)->offset;
 186 }
 187
 188 static inline const struct btrfs_disk_key *path_current_disk_key(struct btrfs_path *path)
 189 {
 190     return (const struct btrfs_disk_key *) &path_current_item(path)->key;
 191 }
 192
 193
 194 static int btrfs_comp_keys(const struct btrfs_disk_key *k1,
 195                            const struct btrfs_disk_key *k2)
 196 {
 197     if (k1->objectid > k2->objectid)
 198         return 1;
 199     if (k1->objectid < k2->objectid)
 200         return -1;
 201     if (k1->type > k2->type)
 202         return 1;
 203     if (k1->type < k2->type)
 204         return -1;
 205     if (k1->offset > k2->offset)
 206         return 1;
 207     if (k1->offset < k2->offset)
 208         return -1;
 209     return 0;
 210 }
 211
 212 /* compare keys but ignore offset, is useful to enumerate all same kind keys */
 213 static int btrfs_comp_keys_type(const struct btrfs_disk_key *k1,
 214                                 const struct btrfs_disk_key *k2)
 215 {
 216     if (k1->objectid > k2->objectid)
 217         return 1;
 218     if (k1->objectid < k2->objectid)
 219         return -1;
 220     if (k1->type > k2->type)
 221         return 1;
 222     if (k1->type < k2->type)
 223         return -1;
 224     return 0;
 225 }
 226
 227 /*
 228  * from sys_chunk_array or chunk_tree, we can convert a logical address to
 229  * a physical address we can not support multi device case yet
 230  */
 231 static u64 logical_physical(u64 logical)
 232 {
 233     struct btrfs_chunk_map *chunk_map = &BtrFsInfo->ChunkMap;
 234     struct btrfs_chunk_map_item item;
 235     int slot, ret;
 236
 237     item.logical = logical;
 238     ret = bin_search(chunk_map->map, sizeof(chunk_map->map[0]), &item,
 239                      (cmp_func) btrfs_comp_chunk_map, 0,
 240                      chunk_map->cur_length, &slot);
 241     if (ret == 0)
 242         slot++;
 243     else if (slot == 0)
 244         return INVALID_ADDRESS;
 245     if (logical >= chunk_map->map[slot - 1].logical + chunk_map->map[slot - 1].length)
 246         return INVALID_ADDRESS;
 247
 248     TRACE("Address translation: 0x%llx -> 0x%llx\n", logical,
 249           chunk_map->map[slot - 1].physical + logical - chunk_map->map[slot - 1].logical);
 250
 251     return chunk_map->map[slot - 1].physical + logical - chunk_map->map[slot - 1].logical;
 252 }
 253
 254 static BOOLEAN disk_read(u64 physical, void *dest, u32 count)
 255 {
 256     LARGE_INTEGER Position;
 257     ULONG Count;
 258     ARC_STATUS Status;
 259
 260     if (!dest)
 261         return FALSE;
 262
 263     Position.QuadPart = physical;
 264     Status = ArcSeek(BtrFsInfo->DeviceId, &Position, SeekAbsolute);
 265     if (Status != ESUCCESS)
 266     {
 267         ERR("ArcSeek returned status %lu\n", Status);
 268         return FALSE;
 269     }
 270
 271     Status = ArcRead(BtrFsInfo->DeviceId, dest, count, &Count);
 272     if (Status != ESUCCESS || Count != count)
 273     {
 274         ERR("ArcRead returned status %lu\n", Status);
 275         return FALSE;
 276     }
 277
 278     return TRUE;
 279 }
 280
 281 static BOOLEAN _BtrFsSearchTree(u64 loffset, u8 level, struct btrfs_disk_key *key,
 282                                 struct btrfs_path *path)
 283 {
 284     struct btrfs_super_block *sb = &BtrFsInfo->SuperBlock;
 285     union tree_buf *tree_buf = path->tree_buf;
 286     int slot, ret, lvl;
 287     u64 physical, logical = loffset;
 288     TRACE("BtrFsSearchTree called: offset: 0x%llx, level: %u (%llu %u %llu)\n",
 289           loffset, level, key->objectid, key->type, key->offset);
 290
 291     if (!tree_buf)
 292     {
 293         ERR("Path struct is not allocated\n");
 294         return FALSE;
 295     }
 296
 297     for (lvl = level; lvl >= 0; lvl--)
 298     {
 299         physical = logical_physical(logical);
 300
 301         if (!disk_read(physical, &tree_buf->header, sb->nodesize))
 302         {
 303             ERR("Error when reading tree node, loffset: 0x%llx, poffset: 0x%llx, level: %u\n", logical, physical, lvl);
 304             return FALSE;
 305         }
 306
 307
 308         if (tree_buf->header.level != lvl)
 309         {
 310             ERR("Error when searching in tree: expected lvl=%u but got %u\n", lvl, tree_buf->header.level);
 311             return FALSE;
 312         }
 313
 314         TRACE("BtrFsSearchTree loop, level %u, loffset: 0x%llx\n", lvl, logical);
 315
 316         if (lvl)
 317         {
 318             ret = bin_search(tree_buf->node.ptrs,
 319                              sizeof(struct btrfs_key_ptr),
 320                              key, (cmp_func) btrfs_comp_keys,
 321                              path->slots[lvl],
 322                              tree_buf->header.nritems, &slot);
 323             TRACE("Inner node, min=%lu max=%lu\n", path->slots[0], tree_buf->header.nritems);
 324             if (ret && slot > path->slots[lvl])
 325                 --slot;
 326         }
 327         else
 328         {
 329             ret = bin_search(tree_buf->leaf.items,
 330                              sizeof(struct btrfs_item),
 331                              key, (cmp_func) btrfs_comp_keys,
 332                              path->slots[0],
 333                              tree_buf->header.nritems, &slot);
 334             TRACE("Leaf node, min=%lu max=%lu\n", path->slots[0], tree_buf->header.nritems);
 335             if (slot == tree_buf->header.nritems)
 336                 --slot;
 337         }
 338
 339         path->itemsnr[lvl] = tree_buf->header.nritems;
 340         path->offsets[lvl] = logical;
 341         path->slots[lvl] = slot;
 342
 343         logical = tree_buf->node.ptrs[slot].blockptr;
 344     }
 345
 346     TRACE("Found slot no=%lu\n", slot);
 347
 348     TRACE("BtrFsSearchTree found item (%llu %u %llu) offset: %lu, size: %lu, returning %lu\n",
 349           path_current_disk_key(path)->objectid, path_current_disk_key(path)->type, path_current_disk_key(path)->offset,
 350           path_current_item(path)->offset, path_current_item(path)->size, !ret);
 351
 352     return !ret;
 353 }
 354
 355 static inline BOOLEAN
 356 BtrFsSearchTree(const struct btrfs_root_item *root, struct btrfs_disk_key *key, struct btrfs_path *path)
 357 {
 358     return _BtrFsSearchTree(root->bytenr, root->level, key, path);
 359 }
 360
 361 static inline BOOLEAN
 362 BtrFsSearchTreeType(const struct btrfs_root_item *root, u64 objectid, u8 type, struct btrfs_path *path)
 363 {
 364     struct btrfs_disk_key key;
 365
 366     key.objectid = objectid;
 367     key.type = type;
 368     key.offset = 0;
 369
 370     _BtrFsSearchTree(root->bytenr, root->level, &key, path);
 371
 372     if (path_current_disk_key(path)->objectid && !btrfs_comp_keys_type(&key, path_current_disk_key(path)))
 373         return TRUE;
 374     else
 375         return FALSE;
 376 }
 377
 378 /* return 0 if slot found */
 379 static int next_slot(struct btrfs_disk_key *key,
 380                      struct btrfs_path *path)
 381 {
 382     int slot, level = 1;
 383
 384     if (!path->itemsnr[0])
 385         return 1;
 386     slot = path->slots[0] + 1;
 387     if (slot >= path->itemsnr[0])
 388     {
 389         /* jumping to next leaf */
 390         while (level < BTRFS_MAX_LEVEL)
 391         {
 392             if (!path->itemsnr[level]) /* no more nodes */
 393                 return 1;
 394             slot = path->slots[level] + 1;
 395             if (slot >= path->itemsnr[level])
 396             {
 397                 level++;
 398                 continue;;
 399             }
 400             path->slots[level] = slot;
 401             path->slots[level - 1] = 0; /* reset low level slots info */
 402             path->itemsnr[level - 1] = 0;
 403             path->offsets[level - 1] = 0;
 404             _BtrFsSearchTree(path->offsets[level], level, key, path);
 405             break;
 406         }
 407         if (level == BTRFS_MAX_LEVEL)
 408             return 1;
 409         goto out;
 410     }
 411     path->slots[0] = slot;
 412
 413 out:
 414     if (path_current_disk_key(path)->objectid && !btrfs_comp_keys_type(key, path_current_disk_key(path)))
 415         return 0;
 416     else
 417         return 1;
 418 }
 419
 420 static int prev_slot(struct btrfs_disk_key *key,
 421                      struct btrfs_path *path)
 422 {
 423     if (!path->slots[0])
 424         return 1;
 425     --path->slots[0];
 426     if (path_current_disk_key(path)->objectid && !btrfs_comp_keys_type(key, path_current_disk_key(path)))
 427         return 0;
 428     else
 429         return 1;
 430 }
 431
 432 /*
 433  * read chunk_array in super block
 434  */
 435 static void btrfs_read_sys_chunk_array()
 436 {
 437     struct btrfs_super_block *sb = &BtrFsInfo->SuperBlock;
 438     struct btrfs_disk_key *key;
 439     struct btrfs_chunk *chunk;
 440     u16 cur;
 441
 442     /* read chunk array in superblock */
 443     TRACE("reading chunk array\n-----------------------------\n");
 444     cur = 0;
 445     while (cur < sb->sys_chunk_array_size)
 446     {
 447         key = (struct btrfs_disk_key *) (sb->sys_chunk_array + cur);
 448         TRACE("chunk key objectid: %llx, offset: %llx, type: %u\n", key->objectid, key->offset, key->type);
 449         cur += sizeof(*key);
 450         chunk = (struct btrfs_chunk *) (sb->sys_chunk_array + cur);
 451         TRACE("chunk length: %llx\n", chunk->length);
 452         TRACE("chunk owner: %llu\n", chunk->owner);
 453         TRACE("chunk stripe_len: %llx\n", chunk->stripe_len);
 454         TRACE("chunk type: %llu\n", chunk->type);
 455         TRACE("chunk io_align: %u\n", chunk->io_align);
 456         TRACE("chunk io_width: %u\n", chunk->io_width);
 457         TRACE("chunk sector_size: %u\n", chunk->sector_size);
 458         TRACE("chunk num_stripes: %u\n", chunk->num_stripes);
 459         TRACE("chunk sub_stripes: %u\n", chunk->sub_stripes);
 460
 461         cur += btrfs_chunk_item_size(chunk->num_stripes);
 462         TRACE("read_sys_chunk_array() cur=%d\n", cur);
 463         insert_map((const struct btrfs_disk_key *) key, chunk);
 464     }
 465 }
 466
 467
 468 /*
 469  * read chunk items from chunk_tree and insert them to chunk map
 470  * */
 471 static void btrfs_read_chunk_tree()
 472 {
 473     struct btrfs_super_block *sb = &BtrFsInfo->SuperBlock;
 474     struct btrfs_disk_key ignore_key;
 475     struct btrfs_disk_key search_key;
 476     struct btrfs_chunk *chunk;
 477     struct btrfs_path path;
 478
 479     if (!(sb->flags & BTRFS_SUPER_FLAG_METADUMP))
 480     {
 481         if (sb->num_devices > 1)
 482             TRACE("warning: only support single device btrfs\n");
 483
 484         ignore_key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
 485         ignore_key.type = BTRFS_DEV_ITEM_KEY;
 486
 487         /* read chunk from chunk_tree */
 488         search_key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
 489         search_key.type = BTRFS_CHUNK_ITEM_KEY;
 490         search_key.offset = 0;
 491         init_path(&path);
 492         _BtrFsSearchTree(sb->chunk_root, sb->chunk_root_level, &search_key, &path);
 493         do
 494         {
 495             /* skip information about underlying block
 496              * devices.
 497              */
 498             if (!btrfs_comp_keys_type(&ignore_key, path_current_disk_key(&path)))
 499                 continue;
 500             if (btrfs_comp_keys_type(&search_key, path_current_disk_key(&path)))
 501                 break;
 502
 503             chunk = (struct btrfs_chunk *) (path_current_data(&path));
 504             insert_map(path_current_disk_key(&path), chunk);
 505         } while (!next_slot(&search_key, &path));
 506         free_path(&path);
 507     }
 508 }
 509
 510 ////////////////////////////////////////
 511 ///////////// DIR ITEM
 512 ////////////////////////////////////////
 513
 514 static BOOLEAN verify_dir_item(struct btrfs_dir_item *item, u32 start, u32 total)
 515 {
 516     u16 max_len = BTRFS_NAME_MAX;
 517     u32 end;
 518
 519     if (item->type >= BTRFS_FT_MAX)
 520     {
 521         ERR("Invalid dir item type: %i\n", item->type);
 522         return TRUE;
 523     }
 524
 525     if (item->type == BTRFS_FT_XATTR)
 526         max_len = 255; /* XATTR_NAME_MAX */
 527
 528     end = start + sizeof(*item) + item->name_len;
 529     if (item->name_len > max_len || end > total)
 530     {
 531         ERR("Invalid dir item name len: %u\n", item->name_len);
 532         return TRUE;
 533     }
 534
 535     return FALSE;
 536 }
 537
 538
 539 static struct btrfs_dir_item *BtrFsMatchDirItemName(struct btrfs_path *path, const char *name, int name_len)
 540 {
 541     struct btrfs_dir_item *item = (struct btrfs_dir_item *) path_current_data(path);
 542     u32 cur = 0, this_len;
 543     const char *name_ptr;
 544
 545     while (cur < path_current_item(path)->size)
 546     {
 547         this_len = sizeof(*item) + item->name_len + item->data_len;
 548         name_ptr = (const char *) item + sizeof(*item);
 549
 550         if (verify_dir_item(item, cur, this_len))
 551             return NULL;
 552         if (item->name_len == name_len && !memcmp(name_ptr, name, name_len))
 553             return item;
 554
 555         cur += this_len;
 556         item = (struct btrfs_dir_item *) ((u8 *) item + this_len);
 557     }
 558
 559     return NULL;
 560 }
 561
 562 static BOOLEAN BtrFsLookupDirItem(const struct btrfs_root_item *root, u64 dir, const char *name, int name_len,
 563                                   struct btrfs_dir_item *item)
 564 {
 565     struct btrfs_path path;
 566     struct btrfs_disk_key key;
 567     struct btrfs_dir_item *res = NULL;
 568
 569     key.objectid = dir;
 570     key.type = BTRFS_DIR_ITEM_KEY;
 571     key.offset = btrfs_crc32c(name, name_len);
 572     init_path(&path);
 573
 574     if (!BtrFsSearchTree(root, &key, &path))
 575     {
 576         free_path(&path);
 577         return FALSE;
 578     }
 579
 580     res = BtrFsMatchDirItemName(&path, name, name_len);
 581     if (res)
 582         *item = *res;
 583     free_path(&path);
 584
 585     return res != NULL;
 586 }
 587
 588 static BOOLEAN BtrFsLookupDirItemI(const struct btrfs_root_item *root, u64 dir_haystack, const char *name, int name_len,
 589                                    struct btrfs_dir_item *ret_item)
 590 {
 591     struct btrfs_path path;
 592     struct btrfs_disk_key key;
 593     struct btrfs_dir_item *item;
 594     char *name_buf;
 595     BOOLEAN result = FALSE;
 596
 597     key.objectid = dir_haystack;
 598     key.type = BTRFS_DIR_INDEX_KEY;
 599     key.offset = 0;
 600     init_path(&path);
 601
 602     BtrFsSearchTree(root, &key, &path);
 603
 604     if (btrfs_comp_keys_type(&key, path_current_disk_key(&path)))
 605         goto cleanup;
 606
 607     do
 608     {
 609         item = (struct btrfs_dir_item *) path_current_data(&path);
 610         // TRACE("slot: %ld, KEY (%llu %u %llu) %.*s\n",
 611         //         path.slots[0], path.item.key.objectid, path.item.key.type,
 612         //         path.item.key.offset, item->name_len, (char *)item + sizeof(*item));
 613
 614         if (verify_dir_item(item, 0, sizeof(*item) + item->name_len))
 615             continue;
 616         if (item->type == BTRFS_FT_XATTR)
 617             continue;
 618
 619         name_buf = (char *) item + sizeof(*item);
 620         TRACE("Compare names %.*s and %.*s\n", name_len, name, item->name_len, name_buf);
 621
 622         if (_strnicmp(name, name_buf, name_len) == 0)
 623         {
 624             *ret_item = *item;
 625             result = TRUE;
 626             goto cleanup;
 627         }
 628
 629     } while (!next_slot(&key, &path));
 630
 631 cleanup:
 632     free_path(&path);
 633     return result;
 634 }
 635
 636 ////////////////////////////////////////
 637 ///////////// EXTENTS
 638 ////////////////////////////////////////
 639
 640 static u64 btrfs_read_extent_inline(struct btrfs_path *path,
 641                                     struct btrfs_file_extent_item *extent, u64 offset,
 642                                     u64 size, char *out)
 643 {
 644     u32 dlen;
 645     const char *cbuf;
 646     const int data_off = offsetof(
 647     struct btrfs_file_extent_item, disk_bytenr);
 648
 649     cbuf = (const char *) extent + data_off;
 650     dlen = extent->ram_bytes;
 651
 652     TRACE("read_extent_inline offset=%llu size=%llu gener=%llu\n", offset, size, extent->generation);
 653
 654     if (offset > dlen)
 655     {
 656         ERR("Tried to read offset (%llu) beyond extent length (%lu)\n", offset, dlen);
 657         return READ_ERROR;
 658     }
 659
 660     if (size > dlen - offset)
 661         size = dlen - offset;
 662
 663     if (extent->compression == BTRFS_COMPRESS_NONE)
 664     {
 665         TRACE("read_extent_inline %lu, \n", data_off);
 666         memcpy(out, cbuf + offset, size);
 667         return size;
 668     }
 669
 670     ERR("No compression supported right now\n");
 671     return READ_ERROR;
 672 }
 673
 674 static u64 btrfs_read_extent_reg(struct btrfs_path *path, struct btrfs_file_extent_item *extent,
 675                                  u64 offset, u64 size, char *out)
 676 {
 677     u64 physical, dlen;
 678     char *temp_out;
 679     dlen = extent->num_bytes;
 680
 681     if (offset > dlen)
 682     {
 683         ERR("Tried to read offset (%llu) beyond extent length (%lu)\n", offset, dlen);
 684         return READ_ERROR;
 685     }
 686
 687     if (size > dlen - offset)
 688         size = dlen - offset;
 689
 690     physical = logical_physical(extent->disk_bytenr);
 691     if (physical == INVALID_ADDRESS)
 692     {
 693         ERR("Unable to convert logical address to physical: %llu\n", extent->disk_bytenr);
 694         return READ_ERROR;
 695     }
 696
 697     if (extent->compression == BTRFS_COMPRESS_NONE)
 698     {
 699         physical += extent->offset + offset;
 700         if (physical & (512 - 1))
 701         {
 702             /* If somebody tried to do unaligned access */
 703             physical -= offset;
 704             temp_out = FrLdrTempAlloc(size + offset, TAG_BTRFS_FILE);
 705
 706             if (!disk_read(physical, temp_out, size + offset))
 707             {
 708                 FrLdrTempFree(temp_out, TAG_BTRFS_FILE);
 709                 return READ_ERROR;
 710             }
 711
 712             memcpy(out, temp_out + offset, size);
 713             FrLdrTempFree(temp_out, TAG_BTRFS_FILE);
 714         } else
 715         {
 716             if (!disk_read(physical, out, size))
 717                 return READ_ERROR;
 718         }
 719
 720         return size;
 721     }
 722
 723     ERR("No compression supported right now\n");
 724     return READ_ERROR;
 725 }
 726
 727 static u64 btrfs_file_read(const struct btrfs_root_item *root, u64 inr, u64 offset, u64 size, char *buf)
 728 {
 729     struct btrfs_path path;
 730     struct btrfs_disk_key key;
 731     struct btrfs_file_extent_item *extent;
 732     int res = 0;
 733     u64 rd, seek_pointer = READ_ERROR, offset_in_extent;
 734     BOOLEAN find_res;
 735
 736     TRACE("btrfs_file_read inr=%llu offset=%llu size=%llu\n", inr, offset, size);
 737
 738     key.objectid = inr;
 739     key.type = BTRFS_EXTENT_DATA_KEY;
 740     key.offset = offset;
 741     init_path(&path);
 742
 743     find_res = BtrFsSearchTree(root, &key, &path);
 744
 745     /* if we found greater key, switch to the previous one */
 746     if (!find_res && btrfs_comp_keys(&key, path_current_disk_key(&path)) < 0)
 747     {
 748         if (prev_slot(&key, &path))
 749             goto out;
 750
 751     } else if (btrfs_comp_keys_type(&key, path_current_disk_key(&path)))
 752     {
 753         goto out;
 754     }
 755
 756     seek_pointer = offset;
 757
 758     do
 759     {
 760         TRACE("Current extent: (%llu %u %llu) \n",
 761               path_current_disk_key(&path)->objectid,
 762               path_current_disk_key(&path)->type,
 763               path_current_disk_key(&path)->offset);
 764
 765         extent = (struct btrfs_file_extent_item *) path_current_data(&path);
 766
 767         offset_in_extent = seek_pointer;
 768         /* check if we need clean extent offset when switching to the next extent */
 769         if ((seek_pointer) >= path_current_disk_key(&path)->offset)
 770             offset_in_extent -= path_current_disk_key(&path)->offset;
 771
 772         if (extent->type == BTRFS_FILE_EXTENT_INLINE)
 773         {
 774             rd = btrfs_read_extent_inline(&path, extent, offset_in_extent, size, buf);
 775         }
 776         else
 777         {
 778             rd = btrfs_read_extent_reg(&path, extent, offset_in_extent, size, buf);
 779         }
 780
 781         if (rd == READ_ERROR)
 782         {
 783             ERR("Error while reading extent\n");
 784             seek_pointer = READ_ERROR;
 785             goto out;
 786         }
 787
 788         buf += rd;
 789         seek_pointer += rd;
 790         size -= rd;
 791         TRACE("file_read size=%llu rd=%llu seek_pointer=%llu\n", size, rd, seek_pointer);
 792
 793         if (!size)
 794             break;
 795     } while (!(res = next_slot(&key, &path)));
 796
 797     if (res)
 798     {
 799         seek_pointer = READ_ERROR;
 800         goto out;
 801     }
 802
 803     seek_pointer -= offset;
 804 out:
 805     free_path(&path);
 806     return seek_pointer;
 807 }
 808
 809 ////////////////////////////////////////
 810 ///////////// INODE
 811 ////////////////////////////////////////
 812
 813
 814 static u64 btrfs_lookup_inode_ref(const struct btrfs_root_item *root, u64 inr,
 815                                   struct btrfs_inode_ref *refp, char *name)
 816 {
 817     struct btrfs_path path;
 818     struct btrfs_inode_ref *ref;
 819     u64 ret = INVALID_INODE;
 820     init_path(&path);
 821
 822     if (BtrFsSearchTreeType(root, inr, BTRFS_INODE_REF_KEY, &path))
 823     {
 824         ref = (struct btrfs_inode_ref *) path_current_data(&path);
 825
 826         if (refp)
 827             *refp = *ref;
 828         ret = path_current_disk_key(&path)->offset;
 829     }
 830
 831     free_path(&path);
 832     return ret;
 833 }
 834
 835 static int btrfs_lookup_inode(const struct btrfs_root_item *root,
 836                               struct btrfs_disk_key *location,
 837                               struct btrfs_inode_item *item,
 838                               struct btrfs_root_item *new_root)
 839 {
 840     const struct btrfs_root_item tmp_root = *root;
 841     struct btrfs_path path;
 842     int res = -1;
 843
 844 //    if (location->type == BTRFS_ROOT_ITEM_KEY) {
 845 //        if (btrfs_find_root(location->objectid, &tmp_root, NULL))
 846 //            return -1;
 847 //
 848 //        location->objectid = tmp_root.root_dirid;
 849 //        location->type = BTRFS_INODE_ITEM_KEY;
 850 //        location->offset = 0;
 851 //    }
 852     init_path(&path);
 853     TRACE("Searching inode (%llu %u %llu)\n", location->objectid, location->type, location->offset);
 854
 855     if (BtrFsSearchTree(&tmp_root, location, &path))
 856     {
 857         if (item)
 858             *item = *((struct btrfs_inode_item *) path_current_data(&path));
 859
 860         if (new_root)
 861             *new_root = tmp_root;
 862
 863         res = 0;
 864     }
 865
 866     free_path(&path);
 867     return res;
 868 }
 869
 870 static BOOLEAN btrfs_readlink(const struct btrfs_root_item *root, u64 inr, char **target)
 871 {
 872     struct btrfs_path path;
 873     struct btrfs_file_extent_item *extent;
 874     char *data_ptr;
 875     BOOLEAN res = FALSE;
 876
 877     init_path(&path);
 878
 879     if (!BtrFsSearchTreeType(root, inr, BTRFS_EXTENT_DATA_KEY, &path))
 880         goto out;
 881
 882     extent = (struct btrfs_file_extent_item *) path_current_data(&path);
 883     if (extent->type != BTRFS_FILE_EXTENT_INLINE)
 884     {
 885         ERR("Extent for symlink %llu not of INLINE type\n", inr);
 886         goto out;
 887     }
 888
 889     if (extent->compression != BTRFS_COMPRESS_NONE)
 890     {
 891         ERR("Symlink %llu extent data compressed!\n", inr);
 892         goto out;
 893     }
 894     else if (extent->encryption != 0)
 895     {
 896         ERR("Symlink %llu extent data encrypted!\n", inr);
 897         goto out;
 898     }
 899     else if (extent->ram_bytes >= BtrFsInfo->SuperBlock.sectorsize)
 900     {
 901         ERR("Symlink %llu extent data too long (%llu)!\n", inr, extent->ram_bytes);
 902         goto out;
 903     }
 904
 905     data_ptr = (char *) extent + offsetof(
 906     struct btrfs_file_extent_item, disk_bytenr);
 907
 908     *target = FrLdrTempAlloc(extent->ram_bytes + 1, TAG_BTRFS_LINK);
 909     if (!*target)
 910     {
 911         ERR("Cannot allocate %llu bytes\n", extent->ram_bytes + 1);
 912         goto out;
 913     }
 914
 915     memcpy(*target, data_ptr, extent->ram_bytes);
 916     (*target)[extent->ram_bytes] = '\0';
 917
 918     res = TRUE;
 919
 920 out:
 921     free_path(&path);
 922     return res;
 923 }
 924
 925 /* inr must be a directory (for regular files with multiple hard links this
 926    function returns only one of the parents of the file) */
 927 static u64 get_parent_inode(const struct btrfs_root_item *root, u64 inr,
 928                             struct btrfs_inode_item *inode_item)
 929 {
 930     struct btrfs_disk_key key;
 931     u64 res;
 932
 933     if (inr == BTRFS_FIRST_FREE_OBJECTID)
 934     {
 935 //        if (root->objectid != btrfs_info.fs_root.objectid) {
 936 //            u64 parent;
 937 //            struct btrfs_root_ref ref;
 938 //
 939 //            parent = btrfs_lookup_root_ref(root->objectid, &ref,
 940 //                                           NULL);
 941 //            if (parent == -1ULL)
 942 //                return -1ULL;
 943 //
 944 //            if (btrfs_find_root(parent, root, NULL))
 945 //                return -1ULL;
 946 //
 947 //            inr = ref.dirid;
 948 //        }
 949
 950         if (inode_item)
 951         {
 952             key.objectid = inr;
 953             key.type = BTRFS_INODE_ITEM_KEY;
 954             key.offset = 0;
 955
 956             if (btrfs_lookup_inode(root, &key, inode_item, NULL))
 957                 return INVALID_INODE;
 958         }
 959
 960         return inr;
 961     }
 962
 963     res = btrfs_lookup_inode_ref(root, inr, NULL, NULL);
 964     if (res == INVALID_INODE)
 965         return INVALID_INODE;
 966
 967     if (inode_item)
 968     {
 969         key.objectid = res;
 970         key.type = BTRFS_INODE_ITEM_KEY;
 971         key.offset = 0;
 972
 973         if (btrfs_lookup_inode(root, &key, inode_item, NULL))
 974             return INVALID_INODE;
 975     }
 976
 977     return res;
 978 }
 979
 980 static inline int next_length(const char *path)
 981 {
 982     int res = 0;
 983     while (*path != '\0' && *path != '/' && *path != '\\' && res <= BTRFS_NAME_MAX)
 984         ++res, ++path;
 985     return res;
 986 }
 987
 988 static inline const char *skip_current_directories(const char *cur)
 989 {
 990     while (1)
 991     {
 992         if (cur[0] == '/' || cur[0] == '\\')
 993             ++cur;
 994         else if (cur[0] == '.' && (cur[1] == '/' || cur[1] == '\\'))
 995             cur += 2;
 996         else
 997             break;
 998     }
 999
1000     return cur;
1001 }
1002
1003 static u64 btrfs_lookup_path(const struct btrfs_root_item *root, u64 inr, const char *path,
1004                              u8 *type_p, struct btrfs_inode_item *inode_item_p, int symlink_limit)
1005 {
1006     struct btrfs_dir_item item;
1007     struct btrfs_inode_item inode_item;
1008     u8 type = BTRFS_FT_DIR;
1009     int len, have_inode = 0;
1010     const char *cur = path;
1011     struct btrfs_disk_key key;
1012     char *link_target = NULL;
1013
1014     if (*cur == '/' || *cur == '\\')
1015     {
1016         ++cur;
1017         inr = root->root_dirid;
1018     }
1019
1020     do
1021     {
1022         cur = skip_current_directories(cur);
1023
1024         len = next_length(cur);
1025         if (len > BTRFS_NAME_MAX)
1026         {
1027             ERR("%s: Name too long at \"%.*s\"\n", BTRFS_NAME_MAX, cur);
1028             return INVALID_INODE;
1029         }
1030
1031         if (len == 1 && cur[0] == '.')
1032             break;
1033
1034         if (len == 2 && cur[0] == '.' && cur[1] == '.')
1035         {
1036             cur += 2;
1037             inr = get_parent_inode(root, inr, &inode_item);
1038             if (inr == INVALID_INODE)
1039                 return INVALID_INODE;
1040
1041             type = BTRFS_FT_DIR;
1042             continue;
1043         }
1044
1045         if (!*cur)
1046             break;
1047
1048         if (!BtrFsLookupDirItem(root, inr, cur, len, &item))
1049         {
1050             TRACE("Try to find case-insensitive, path=%s inr=%llu s=%.*s\n", path, inr, len, cur);
1051             if (!BtrFsLookupDirItemI(root, inr, cur, len, &item))
1052                 return INVALID_INODE;
1053         }
1054
1055         type = item.type;
1056         have_inode = 1;
1057         if (btrfs_lookup_inode(root, &item.location, &inode_item, NULL))
1058             return INVALID_INODE;
1059
1060         if (type == BTRFS_FT_SYMLINK && symlink_limit >= 0)
1061         {
1062             if (!symlink_limit)
1063             {
1064                 TRACE("%s: Too much symlinks!\n");
1065                 return INVALID_INODE;
1066             }
1067
1068             /* btrfs_readlink allocates link_target by itself */
1069             if (!btrfs_readlink(root, item.location.objectid, &link_target))
1070                 return INVALID_INODE;
1071
1072             inr = btrfs_lookup_path(root, inr, link_target, &type, &inode_item, symlink_limit - 1);
1073
1074             FrLdrTempFree(link_target, TAG_BTRFS_LINK);
1075
1076             if (inr == INVALID_INODE)
1077                 return INVALID_INODE;
1078         } else if (type != BTRFS_FT_DIR && cur[len])
1079         {
1080             TRACE("%s: \"%.*s\" not a directory\n", (int) (cur - path + len), path);
1081             return INVALID_INODE;
1082         } else
1083         {
1084             inr = item.location.objectid;
1085         }
1086
1087         cur += len;
1088     } while (*cur);
1089
1090     if (type_p)
1091         *type_p = type;
1092
1093     if (inode_item_p)
1094     {
1095         if (!have_inode)
1096         {
1097             key.objectid = inr;
1098             key.type = BTRFS_INODE_ITEM_KEY;
1099             key.offset = 0;
1100
1101             if (btrfs_lookup_inode(root, &key, &inode_item, NULL))
1102                 return INVALID_INODE;
1103         }
1104
1105         *inode_item_p = inode_item;
1106     }
1107
1108     return inr;
1109 }
1110
1111
1112 ARC_STATUS BtrFsClose(ULONG FileId)
1113 {
1114     pbtrfs_file_info phandle = FsGetDeviceSpecific(FileId);
1115     TRACE("BtrFsClose %lu\n", FileId);
1116
1117     FrLdrTempFree(phandle, TAG_BTRFS_FILE);
1118
1119     return ESUCCESS;
1120 }
1121
1122 ARC_STATUS BtrFsGetFileInformation(ULONG FileId, FILEINFORMATION *Information)
1123 {
1124     pbtrfs_file_info phandle = FsGetDeviceSpecific(FileId);
1125
1126     RtlZeroMemory(Information, sizeof(*Information));
1127     Information->EndingAddress.QuadPart = phandle->inode.size;
1128     Information->CurrentAddress.QuadPart = phandle->position;
1129
1130     TRACE("BtrFsGetFileInformation(%lu) -> FileSize = %llu, FilePointer = 0x%llx\n",
1131           FileId, Information->EndingAddress.QuadPart, Information->CurrentAddress.QuadPart);
1132
1133     return ESUCCESS;
1134 }
1135
1136 ARC_STATUS BtrFsOpen(CHAR *Path, OPENMODE OpenMode, ULONG *FileId)
1137 {
1138     u64 inr;
1139     u8 type;
1140
1141     btrfs_file_info temp_file_info;
1142     pbtrfs_file_info phandle;
1143
1144     TRACE("BtrFsOpen %s\n", Path);
1145
1146     if (OpenMode != OpenReadOnly)
1147         return EACCES;
1148
1149     inr = btrfs_lookup_path(&BtrFsInfo->FsRoot, BtrFsInfo->FsRoot.root_dirid, Path, &type, &temp_file_info.inode, 40);
1150
1151     if (inr == INVALID_INODE)
1152     {
1153         TRACE("Cannot lookup file %s\n", Path);
1154         return ENOENT;
1155     }
1156
1157     if (type != BTRFS_FT_REG_FILE)
1158     {
1159         TRACE("Not a regular file: %s\n", Path);
1160         return EISDIR;
1161     }
1162
1163     TRACE("found inode inr=%llu size=%llu\n", inr, temp_file_info.inode.size);
1164
1165     temp_file_info.inr = inr;
1166     temp_file_info.position = 0;
1167
1168     phandle = FrLdrTempAlloc(sizeof(btrfs_file_info), TAG_BTRFS_FILE);
1169     if (!phandle)
1170         return ENOMEM;
1171
1172     memcpy(phandle, &temp_file_info, sizeof(btrfs_file_info));
1173
1174     FsSetDeviceSpecific(*FileId, phandle);
1175     return ESUCCESS;
1176 }
1177
1178 ARC_STATUS BtrFsRead(ULONG FileId, VOID *Buffer, ULONG Size, ULONG *BytesRead)
1179 {
1180     pbtrfs_file_info phandle = FsGetDeviceSpecific(FileId);
1181     u64 rd;
1182
1183     TRACE("BtrFsRead %lu, size=%lu \n", FileId, Size);
1184
1185     if (!Size)
1186         Size = phandle->inode.size;
1187
1188     if (Size > phandle->inode.size)
1189         Size = phandle->inode.size;
1190
1191     rd = btrfs_file_read(&BtrFsInfo->FsRoot, phandle->inr, phandle->position, Size, Buffer);
1192     if (rd == READ_ERROR)
1193     {
1194         TRACE("An error occured while reading file %lu\n", FileId);
1195         return ENOENT;
1196     }
1197
1198     *BytesRead = rd;
1199     return ESUCCESS;
1200 }
1201
1202 ARC_STATUS BtrFsSeek(ULONG FileId, LARGE_INTEGER *Position, SEEKMODE SeekMode)
1203 {
1204     pbtrfs_file_info phandle = FsGetDeviceSpecific(FileId);
1205
1206     TRACE("BtrFsSeek %lu NewFilePointer = %llu\n", FileId, Position->QuadPart);
1207
1208     if (SeekMode != SeekAbsolute)
1209         return EINVAL;
1210     if (Position->QuadPart >= phandle->inode.size)
1211         return EINVAL;
1212
1213     phandle->position = Position->QuadPart;
1214     return ESUCCESS;
1215 }
1216
1217 const DEVVTBL BtrFsFuncTable =
1218 {
1219     BtrFsClose,
1220     BtrFsGetFileInformation,
1221     BtrFsOpen,
1222     BtrFsRead,
1223     BtrFsSeek,
1224     L"btrfs",
1225 };
1226
1227 const DEVVTBL *BtrFsMount(ULONG DeviceId)
1228 {
1229     struct btrfs_path path;
1230     struct btrfs_root_item fs_root_item;
1231
1232     TRACE("Enter BtrFsMount(%lu)\n", DeviceId);
1233
1234     BtrFsInfo = FrLdrTempAlloc(sizeof(struct BTRFS_INFO), TAG_BTRFS_INFO);
1235     if (!BtrFsInfo)
1236         return NULL;
1237     RtlZeroMemory(BtrFsInfo, sizeof(struct BTRFS_INFO));
1238
1239     /* Read the SuperBlock */
1240     if (!disk_read(BTRFS_SUPER_INFO_OFFSET, &BtrFsInfo->SuperBlock, sizeof(struct btrfs_super_block)))
1241     {
1242         FrLdrTempFree(BtrFsInfo, TAG_BTRFS_INFO);
1243         return NULL;
1244     }
1245
1246     /* Check if SuperBlock is valid. If yes, return BTRFS function table */
1247     if (BtrFsInfo->SuperBlock.magic != BTRFS_MAGIC_N)
1248     {
1249         FrLdrTempFree(BtrFsInfo, TAG_BTRFS_INFO);
1250         return NULL;
1251     }
1252
1253     BtrFsInfo->DeviceId = DeviceId;
1254     TRACE("BtrFsMount(%lu) superblock magic ok\n", DeviceId);
1255
1256     btrfs_init_crc32c();
1257
1258     btrfs_read_sys_chunk_array();
1259     btrfs_read_chunk_tree();
1260
1261     /* setup roots */
1262     fs_root_item.bytenr = BtrFsInfo->SuperBlock.root;
1263     fs_root_item.level = BtrFsInfo->SuperBlock.root_level;
1264
1265     init_path(&path);
1266     if (!BtrFsSearchTreeType(&fs_root_item, BTRFS_FS_TREE_OBJECTID, BTRFS_ROOT_ITEM_KEY, &path))
1267     {
1268         FrLdrTempFree(BtrFsInfo, TAG_BTRFS_INFO);
1269         free_path(&path);
1270         return NULL;
1271     }
1272
1273     BtrFsInfo->FsRoot = *(struct btrfs_root_item *) path_current_data(&path);
1274
1275     free_path(&path);
1276
1277     TRACE("BtrFsMount(%lu) success\n", DeviceId);
1278     return &BtrFsFuncTable;
1279 }