libexfat/node.c

   1 /*
   2         node.c (09.10.09)
   3         exFAT file system implementation library.
   4
   5         Free exFAT implementation.
   6         Copyright (C) 2010-2013  Andrew Nayenko
   7
   8         This program is free software; you can redistribute it and/or modify
   9         it under the terms of the GNU General Public License as published by
  10         the Free Software Foundation, either version 2 of the License, or
  11         (at your option) any later version.
  12
  13         This program is distributed in the hope that it will be useful,
  14         but WITHOUT ANY WARRANTY; without even the implied warranty of
  15         MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16         GNU General Public License for more details.
  17
  18         You should have received a copy of the GNU General Public License along
  19         with this program; if not, write to the Free Software Foundation, Inc.,
  20         51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  21 */
  22
  23 #include "exfat.h"
  24 #include <errno.h>
  25 #include <string.h>
  26 #include <inttypes.h>
  27
  28 /* on-disk nodes iterator */
  29 struct iterator
  30 {
  31         cluster_t cluster;
  32         off_t offset;
  33         int contiguous;
  34         char* chunk;
  35 };
  36
  37 struct exfat_node* exfat_get_node(struct exfat_node* node)
  38 {
  39         /* if we switch to multi-threaded mode we will need atomic
  40            increment here and atomic decrement in exfat_put_node() */
  41         node->references++;
  42         return node;
  43 }
  44
  45 void exfat_put_node(struct exfat* ef, struct exfat_node* node)
  46 {
  47         if (--node->references < 0)
  48         {
  49                 char buffer[UTF8_BYTES(EXFAT_NAME_MAX) + 1];
  50                 exfat_get_name(node, buffer, sizeof(buffer) - 1);
  51                 exfat_bug("reference counter of `%s' is below zero", buffer);
  52         }
  53
  54         if (node->references == 0)
  55         {
  56                 /* FIXME handle I/O error */
  57                 if (exfat_flush_node(ef, node) != 0)
  58                         exfat_bug("node flush failed");
  59                 if (node->flags & EXFAT_ATTRIB_UNLINKED)
  60                 {
  61                         /* free all clusters and node structure itself */
  62                         exfat_truncate(ef, node, 0, true);
  63                         free(node);
  64                 }
  65                 /* FIXME handle I/O error */
  66                 if (exfat_flush(ef) != 0)
  67                         exfat_bug("flush failed");
  68         }
  69 }
  70
  71 /**
  72  * Cluster + offset from the beginning of the directory to absolute offset.
  73  */
  74 static off_t co2o(struct exfat* ef, cluster_t cluster, off_t offset)
  75 {
  76         return exfat_c2o(ef, cluster) + offset % CLUSTER_SIZE(*ef->sb);
  77 }
  78
  79 static int opendir(struct exfat* ef, const struct exfat_node* dir,
  80                 struct iterator* it)
  81 {
  82         if (!(dir->flags & EXFAT_ATTRIB_DIR))
  83                 exfat_bug("not a directory");
  84         it->cluster = dir->start_cluster;
  85         it->offset = 0;
  86         it->contiguous = IS_CONTIGUOUS(*dir);
  87         it->chunk = malloc(CLUSTER_SIZE(*ef->sb));
  88         if (it->chunk == NULL)
  89         {
  90                 exfat_error("out of memory");
  91                 return -ENOMEM;
  92         }
  93         if (exfat_pread(ef->dev, it->chunk, CLUSTER_SIZE(*ef->sb),
  94                         exfat_c2o(ef, it->cluster)) < 0)
  95         {
  96                 exfat_error("failed to read directory cluster %#x", it->cluster);
  97                 return -EIO;
  98         }
  99         return 0;
 100 }
 101
 102 static void closedir(struct iterator* it)
 103 {
 104         it->cluster = 0;
 105         it->offset = 0;
 106         it->contiguous = 0;
 107         free(it->chunk);
 108         it->chunk = NULL;
 109 }
 110
 111 static int fetch_next_entry(struct exfat* ef, const struct exfat_node* parent,
 112                 struct iterator* it)
 113 {
 114         /* move iterator to the next entry in the directory */
 115         it->offset += sizeof(struct exfat_entry);
 116         /* fetch the next cluster if needed */
 117         if ((it->offset & (CLUSTER_SIZE(*ef->sb) - 1)) == 0)
 118         {
 119                 /* reached the end of directory; the caller should check this
 120                    condition too */
 121                 if (it->offset >= parent->size)
 122                         return 0;
 123                 it->cluster = exfat_next_cluster(ef, parent, it->cluster);
 124                 if (CLUSTER_INVALID(it->cluster))
 125                 {
 126                         exfat_error("invalid cluster 0x%x while reading directory",
 127                                         it->cluster);
 128                         return 1;
 129                 }
 130                 if (exfat_pread(ef->dev, it->chunk, CLUSTER_SIZE(*ef->sb),
 131                                 exfat_c2o(ef, it->cluster)) < 0)
 132                 {
 133                         exfat_error("failed to read the next directory cluster %#x",
 134                                         it->cluster);
 135                         return 1;
 136                 }
 137         }
 138         return 0;
 139 }
 140
 141 static struct exfat_node* allocate_node(void)
 142 {
 143         struct exfat_node* node = malloc(sizeof(struct exfat_node));
 144         if (node == NULL)
 145         {
 146                 exfat_error("failed to allocate node");
 147                 return NULL;
 148         }
 149         memset(node, 0, sizeof(struct exfat_node));
 150         return node;
 151 }
 152
 153 static void init_node_meta1(struct exfat_node* node,
 154                 const struct exfat_entry_meta1* meta1)
 155 {
 156         node->flags = le16_to_cpu(meta1->attrib);
 157         node->mtime = exfat_exfat2unix(meta1->mdate, meta1->mtime,
 158                         meta1->mtime_cs);
 159         /* there is no centiseconds field for atime */
 160         node->atime = exfat_exfat2unix(meta1->adate, meta1->atime, 0);
 161 }
 162
 163 static void init_node_meta2(struct exfat_node* node,
 164                 const struct exfat_entry_meta2* meta2)
 165 {
 166         node->size = le64_to_cpu(meta2->size);
 167         node->start_cluster = le32_to_cpu(meta2->start_cluster);
 168         node->fptr_cluster = node->start_cluster;
 169         if (meta2->flags & EXFAT_FLAG_CONTIGUOUS)
 170                 node->flags |= EXFAT_ATTRIB_CONTIGUOUS;
 171 }
 172
 173 static const struct exfat_entry* get_entry_ptr(const struct exfat* ef,
 174                 const struct iterator* it)
 175 {
 176         return (const struct exfat_entry*)
 177                         (it->chunk + it->offset % CLUSTER_SIZE(*ef->sb));
 178 }
 179
 180 static bool check_node(const struct exfat_node* node, uint16_t actual_checksum,
 181                 uint16_t reference_checksum, uint64_t real_size)
 182 {
 183         char buffer[UTF8_BYTES(EXFAT_NAME_MAX) + 1];
 184
 185         /*
 186            Validate checksum first. If it's invalid all other fields probably
 187            contain just garbage.
 188         */
 189         if (actual_checksum != reference_checksum)
 190         {
 191                 exfat_get_name(node, buffer, sizeof(buffer) - 1);
 192                 exfat_error("`%s' has invalid checksum (%#hx != %#hx)", buffer,
 193                                 actual_checksum, reference_checksum);
 194                 return false;
 195         }
 196
 197         /*
 198            It's unclear what is real_size field needed for. It usually equals to
 199            the size but may contain any value less than size (including 0).
 200         */
 201         if (real_size > node->size)
 202         {
 203                 exfat_get_name(node, buffer, sizeof(buffer) - 1);
 204                 exfat_error("`%s' has real size (%"PRIu64") greater than size "
 205                                 "(%"PRIu64")", buffer, real_size, node->size);
 206                 return false;
 207         }
 208
 209         return true;
 210 }
 211
 212 /*
 213  * Reads one entry in directory at position pointed by iterator and fills
 214  * node structure.
 215  */
 216 static int readdir(struct exfat* ef, const struct exfat_node* parent,
 217                 struct exfat_node** node, struct iterator* it)
 218 {
 219         int rc = -EIO;
 220         const struct exfat_entry* entry;
 221         const struct exfat_entry_meta1* meta1;
 222         const struct exfat_entry_meta2* meta2;
 223         const struct exfat_entry_name* file_name;
 224         const struct exfat_entry_upcase* upcase;
 225         const struct exfat_entry_bitmap* bitmap;
 226         const struct exfat_entry_label* label;
 227         uint8_t continuations = 0;
 228         le16_t* namep = NULL;
 229         uint16_t reference_checksum = 0;
 230         uint16_t actual_checksum = 0;
 231         uint64_t real_size = 0;
 232
 233         *node = NULL;
 234
 235         for (;;)
 236         {
 237                 if (it->offset >= parent->size)
 238                 {
 239                         if (continuations != 0)
 240                         {
 241                                 exfat_error("expected %hhu continuations", continuations);
 242                                 goto error;
 243                         }
 244                         return -ENOENT; /* that's OK, means end of directory */
 245                 }
 246
 247                 entry = get_entry_ptr(ef, it);
 248                 switch (entry->type)
 249                 {
 250                 case EXFAT_ENTRY_FILE:
 251                         if (continuations != 0)
 252                         {
 253                                 exfat_error("expected %hhu continuations before new entry",
 254                                                 continuations);
 255                                 goto error;
 256                         }
 257                         meta1 = (const struct exfat_entry_meta1*) entry;
 258                         continuations = meta1->continuations;
 259                         /* each file entry must have at least 2 continuations:
 260                            info and name */
 261                         if (continuations < 2)
 262                         {
 263                                 exfat_error("too few continuations (%hhu)", continuations);
 264                                 goto error;
 265                         }
 266                         if (continuations > 1 +
 267                                         DIV_ROUND_UP(EXFAT_NAME_MAX, EXFAT_ENAME_MAX))
 268                         {
 269                                 exfat_error("too many continuations (%hhu)", continuations);
 270                                 goto error;
 271                         }
 272                         reference_checksum = le16_to_cpu(meta1->checksum);
 273                         actual_checksum = exfat_start_checksum(meta1);
 274                         *node = allocate_node();
 275                         if (*node == NULL)
 276                         {
 277                                 rc = -ENOMEM;
 278                                 goto error;
 279                         }
 280                         /* new node has zero reference counter */
 281                         (*node)->entry_cluster = it->cluster;
 282                         (*node)->entry_offset = it->offset;
 283                         init_node_meta1(*node, meta1);
 284                         namep = (*node)->name;
 285                         break;
 286
 287                 case EXFAT_ENTRY_FILE_INFO:
 288                         if (continuations < 2)
 289                         {
 290                                 exfat_error("unexpected continuation (%hhu)",
 291                                                 continuations);
 292                                 goto error;
 293                         }
 294                         meta2 = (const struct exfat_entry_meta2*) entry;
 295                         if (meta2->flags & ~(EXFAT_FLAG_ALWAYS1 | EXFAT_FLAG_CONTIGUOUS))
 296                         {
 297                                 exfat_error("unknown flags in meta2 (0x%hhx)", meta2->flags);
 298                                 goto error;
 299                         }
 300                         init_node_meta2(*node, meta2);
 301                         actual_checksum = exfat_add_checksum(entry, actual_checksum);
 302                         real_size = le64_to_cpu(meta2->real_size);
 303                         /* empty files must be marked as non-contiguous */
 304                         if ((*node)->size == 0 && (meta2->flags & EXFAT_FLAG_CONTIGUOUS))
 305                         {
 306                                 exfat_error("empty file marked as contiguous (0x%hhx)",
 307                                                 meta2->flags);
 308                                 goto error;
 309                         }
 310                         /* directories must be aligned on at cluster boundary */
 311                         if (((*node)->flags & EXFAT_ATTRIB_DIR) &&
 312                                 (*node)->size % CLUSTER_SIZE(*ef->sb) != 0)
 313                         {
 314                                 exfat_error("directory has invalid size %"PRIu64" bytes",
 315                                                 (*node)->size);
 316                                 goto error;
 317                         }
 318                         --continuations;
 319                         break;
 320
 321                 case EXFAT_ENTRY_FILE_NAME:
 322                         if (continuations == 0)
 323                         {
 324                                 exfat_error("unexpected continuation");
 325                                 goto error;
 326                         }
 327                         file_name = (const struct exfat_entry_name*) entry;
 328                         actual_checksum = exfat_add_checksum(entry, actual_checksum);
 329
 330                         memcpy(namep, file_name->name,
 331                                         MIN(EXFAT_ENAME_MAX,
 332                                                 ((*node)->name + EXFAT_NAME_MAX - namep)) *
 333                                         sizeof(le16_t));
 334                         namep += EXFAT_ENAME_MAX;
 335                         if (--continuations == 0)
 336                         {
 337                                 if (!check_node(*node, actual_checksum, reference_checksum,
 338                                                 real_size))
 339                                         goto error;
 340                                 if (fetch_next_entry(ef, parent, it) != 0)
 341                                         goto error;
 342                                 return 0; /* entry completed */
 343                         }
 344                         break;
 345
 346                 case EXFAT_ENTRY_UPCASE:
 347                         if (ef->upcase != NULL)
 348                                 break;
 349                         upcase = (const struct exfat_entry_upcase*) entry;
 350                         if (CLUSTER_INVALID(le32_to_cpu(upcase->start_cluster)))
 351                         {
 352                                 exfat_error("invalid cluster 0x%x in upcase table",
 353                                                 le32_to_cpu(upcase->start_cluster));
 354                                 goto error;
 355                         }
 356                         if (le64_to_cpu(upcase->size) == 0 ||
 357                                 le64_to_cpu(upcase->size) > 0xffff * sizeof(uint16_t) ||
 358                                 le64_to_cpu(upcase->size) % sizeof(uint16_t) != 0)
 359                         {
 360                                 exfat_error("bad upcase table size (%"PRIu64" bytes)",
 361                                                 le64_to_cpu(upcase->size));
 362                                 goto error;
 363                         }
 364                         ef->upcase = malloc(le64_to_cpu(upcase->size));
 365                         if (ef->upcase == NULL)
 366                         {
 367                                 exfat_error("failed to allocate upcase table (%"PRIu64" bytes)",
 368                                                 le64_to_cpu(upcase->size));
 369                                 rc = -ENOMEM;
 370                                 goto error;
 371                         }
 372                         ef->upcase_chars = le64_to_cpu(upcase->size) / sizeof(le16_t);
 373
 374                         if (exfat_pread(ef->dev, ef->upcase, le64_to_cpu(upcase->size),
 375                                         exfat_c2o(ef, le32_to_cpu(upcase->start_cluster))) < 0)
 376                         {
 377                                 exfat_error("failed to read upper case table "
 378                                                 "(%"PRIu64" bytes starting at cluster %#x)",
 379                                                 le64_to_cpu(upcase->size),
 380                                                 le32_to_cpu(upcase->start_cluster));
 381                                 goto error;
 382                         }
 383                         break;
 384
 385                 case EXFAT_ENTRY_BITMAP:
 386                         bitmap = (const struct exfat_entry_bitmap*) entry;
 387                         ef->cmap.start_cluster = le32_to_cpu(bitmap->start_cluster);
 388                         if (CLUSTER_INVALID(ef->cmap.start_cluster))
 389                         {
 390                                 exfat_error("invalid cluster 0x%x in clusters bitmap",
 391                                                 ef->cmap.start_cluster);
 392                                 goto error;
 393                         }
 394                         ef->cmap.size = le32_to_cpu(ef->sb->cluster_count) -
 395                                 EXFAT_FIRST_DATA_CLUSTER;
 396                         if (le64_to_cpu(bitmap->size) < DIV_ROUND_UP(ef->cmap.size, 8))
 397                         {
 398                                 exfat_error("invalid clusters bitmap size: %"PRIu64
 399                                                 " (expected at least %u)",
 400                                                 le64_to_cpu(bitmap->size),
 401                                                 DIV_ROUND_UP(ef->cmap.size, 8));
 402                                 goto error;
 403                         }
 404                         /* FIXME bitmap can be rather big, up to 512 MB */
 405                         ef->cmap.chunk_size = ef->cmap.size;
 406                         ef->cmap.chunk = malloc(BMAP_SIZE(ef->cmap.chunk_size));
 407                         if (ef->cmap.chunk == NULL)
 408                         {
 409                                 exfat_error("failed to allocate clusters bitmap chunk "
 410                                                 "(%"PRIu64" bytes)", le64_to_cpu(bitmap->size));
 411                                 rc = -ENOMEM;
 412                                 goto error;
 413                         }
 414
 415                         if (exfat_pread(ef->dev, ef->cmap.chunk,
 416                                         BMAP_SIZE(ef->cmap.chunk_size),
 417                                         exfat_c2o(ef, ef->cmap.start_cluster)) < 0)
 418                         {
 419                                 exfat_error("failed to read clusters bitmap "
 420                                                 "(%"PRIu64" bytes starting at cluster %#x)",
 421                                                 le64_to_cpu(bitmap->size), ef->cmap.start_cluster);
 422                                 goto error;
 423                         }
 424                         break;
 425
 426                 case EXFAT_ENTRY_LABEL:
 427                         label = (const struct exfat_entry_label*) entry;
 428                         if (label->length > EXFAT_ENAME_MAX)
 429                         {
 430                                 exfat_error("too long label (%hhu chars)", label->length);
 431                                 goto error;
 432                         }
 433                         if (utf16_to_utf8(ef->label, label->name,
 434                                                 sizeof(ef->label) - 1, EXFAT_ENAME_MAX) != 0)
 435                                 goto error;
 436                         break;
 437
 438                 default:
 439                         if (entry->type & EXFAT_ENTRY_VALID)
 440                         {
 441                                 exfat_error("unknown entry type 0x%hhx", entry->type);
 442                                 goto error;
 443                         }
 444                         break;
 445                 }
 446
 447                 if (fetch_next_entry(ef, parent, it) != 0)
 448                         goto error;
 449         }
 450         /* we never reach here */
 451
 452 error:
 453         free(*node);
 454         *node = NULL;
 455         return rc;
 456 }
 457
 458 int exfat_cache_directory(struct exfat* ef, struct exfat_node* dir)
 459 {
 460         struct iterator it;
 461         int rc;
 462         struct exfat_node* node;
 463         struct exfat_node* current = NULL;
 464
 465         if (dir->flags & EXFAT_ATTRIB_CACHED)
 466                 return 0; /* already cached */
 467
 468         rc = opendir(ef, dir, &it);
 469         if (rc != 0)
 470                 return rc;
 471         while ((rc = readdir(ef, dir, &node, &it)) == 0)
 472         {
 473                 node->parent = dir;
 474                 if (current != NULL)
 475                 {
 476                         current->next = node;
 477                         node->prev = current;
 478                 }
 479                 else
 480                         dir->child = node;
 481
 482                 current = node;
 483         }
 484         closedir(&it);
 485
 486         if (rc != -ENOENT)
 487         {
 488                 /* rollback */
 489                 for (current = dir->child; current; current = node)
 490                 {
 491                         node = current->next;
 492                         free(current);
 493                 }
 494                 dir->child = NULL;
 495                 return rc;
 496         }
 497
 498         dir->flags |= EXFAT_ATTRIB_CACHED;
 499         return 0;
 500 }
 501
 502 static void tree_attach(struct exfat_node* dir, struct exfat_node* node)
 503 {
 504         node->parent = dir;
 505         if (dir->child)
 506         {
 507                 dir->child->prev = node;
 508                 node->next = dir->child;
 509         }
 510         dir->child = node;
 511 }
 512
 513 static void tree_detach(struct exfat_node* node)
 514 {
 515         if (node->prev)
 516                 node->prev->next = node->next;
 517         else /* this is the first node in the list */
 518                 node->parent->child = node->next;
 519         if (node->next)
 520                 node->next->prev = node->prev;
 521         node->parent = NULL;
 522         node->prev = NULL;
 523         node->next = NULL;
 524 }
 525
 526 static void reset_cache(struct exfat* ef, struct exfat_node* node)
 527 {
 528         while (node->child)
 529         {
 530                 struct exfat_node* p = node->child;
 531                 reset_cache(ef, p);
 532                 tree_detach(p);
 533                 free(p);
 534         }
 535         node->flags &= ~EXFAT_ATTRIB_CACHED;
 536         if (node->references != 0)
 537         {
 538                 char buffer[UTF8_BYTES(EXFAT_NAME_MAX) + 1];
 539                 exfat_get_name(node, buffer, sizeof(buffer) - 1);
 540                 exfat_warn("non-zero reference counter (%d) for `%s'",
 541                                 node->references, buffer);
 542         }
 543         while (node->references)
 544                 exfat_put_node(ef, node);
 545 }
 546
 547 void exfat_reset_cache(struct exfat* ef)
 548 {
 549         reset_cache(ef, ef->root);
 550 }
 551
 552 static bool next_entry(struct exfat* ef, const struct exfat_node* parent,
 553                 cluster_t* cluster, off_t* offset)
 554 {
 555         *offset += sizeof(struct exfat_entry);
 556         if (*offset % CLUSTER_SIZE(*ef->sb) == 0)
 557         {
 558                 *cluster = exfat_next_cluster(ef, parent, *cluster);
 559                 if (CLUSTER_INVALID(*cluster))
 560                 {
 561                         exfat_error("invalid cluster %#x while getting next entry",
 562                                         *cluster);
 563                         return false;
 564                 }
 565         }
 566         return true;
 567 }
 568
 569 int exfat_flush_node(struct exfat* ef, struct exfat_node* node)
 570 {
 571         cluster_t cluster;
 572         off_t offset;
 573         off_t meta1_offset, meta2_offset;
 574         struct exfat_entry_meta1 meta1;
 575         struct exfat_entry_meta2 meta2;
 576
 577         if (!(node->flags & EXFAT_ATTRIB_DIRTY))
 578                 return 0; /* no need to flush */
 579
 580         if (ef->ro)
 581                 exfat_bug("unable to flush node to read-only FS");
 582
 583         if (node->parent == NULL)
 584                 return 0; /* do not flush unlinked node */
 585
 586         cluster = node->entry_cluster;
 587         offset = node->entry_offset;
 588         meta1_offset = co2o(ef, cluster, offset);
 589         if (!next_entry(ef, node->parent, &cluster, &offset))
 590                 return -EIO;
 591         meta2_offset = co2o(ef, cluster, offset);
 592
 593         if (exfat_pread(ef->dev, &meta1, sizeof(meta1), meta1_offset) < 0)
 594         {
 595                 exfat_error("failed to read meta1 entry on flush");
 596                 return -EIO;
 597         }
 598         if (meta1.type != EXFAT_ENTRY_FILE)
 599                 exfat_bug("invalid type of meta1: 0x%hhx", meta1.type);
 600         meta1.attrib = cpu_to_le16(node->flags);
 601         exfat_unix2exfat(node->mtime, &meta1.mdate, &meta1.mtime, &meta1.mtime_cs);
 602         exfat_unix2exfat(node->atime, &meta1.adate, &meta1.atime, NULL);
 603
 604         if (exfat_pread(ef->dev, &meta2, sizeof(meta2), meta2_offset) < 0)
 605         {
 606                 exfat_error("failed to read meta2 entry on flush");
 607                 return -EIO;
 608         }
 609         if (meta2.type != EXFAT_ENTRY_FILE_INFO)
 610                 exfat_bug("invalid type of meta2: 0x%hhx", meta2.type);
 611         meta2.size = meta2.real_size = cpu_to_le64(node->size);
 612         meta2.start_cluster = cpu_to_le32(node->start_cluster);
 613         meta2.flags = EXFAT_FLAG_ALWAYS1;
 614         /* empty files must not be marked as contiguous */
 615         if (node->size != 0 && IS_CONTIGUOUS(*node))
 616                 meta2.flags |= EXFAT_FLAG_CONTIGUOUS;
 617         /* name hash remains unchanged, no need to recalculate it */
 618
 619         meta1.checksum = exfat_calc_checksum(&meta1, &meta2, node->name);
 620
 621         if (exfat_pwrite(ef->dev, &meta1, sizeof(meta1), meta1_offset) < 0)
 622         {
 623                 exfat_error("failed to write meta1 entry on flush");
 624                 return -EIO;
 625         }
 626         if (exfat_pwrite(ef->dev, &meta2, sizeof(meta2), meta2_offset) < 0)
 627         {
 628                 exfat_error("failed to write meta2 entry on flush");
 629                 return -EIO;
 630         }
 631
 632         node->flags &= ~EXFAT_ATTRIB_DIRTY;
 633         return 0;
 634 }
 635
 636 static bool erase_entry(struct exfat* ef, struct exfat_node* node)
 637 {
 638         cluster_t cluster = node->entry_cluster;
 639         off_t offset = node->entry_offset;
 640         int name_entries = DIV_ROUND_UP(utf16_length(node->name), EXFAT_ENAME_MAX);
 641         uint8_t entry_type;
 642
 643         entry_type = EXFAT_ENTRY_FILE & ~EXFAT_ENTRY_VALID;
 644         if (exfat_pwrite(ef->dev, &entry_type, 1, co2o(ef, cluster, offset)) < 0)
 645         {
 646                 exfat_error("failed to erase meta1 entry");
 647                 return false;
 648         }
 649
 650         if (!next_entry(ef, node->parent, &cluster, &offset))
 651                 return false;
 652         entry_type = EXFAT_ENTRY_FILE_INFO & ~EXFAT_ENTRY_VALID;
 653         if (exfat_pwrite(ef->dev, &entry_type, 1, co2o(ef, cluster, offset)) < 0)
 654         {
 655                 exfat_error("failed to erase meta2 entry");
 656                 return false;
 657         }
 658
 659         while (name_entries--)
 660         {
 661                 if (!next_entry(ef, node->parent, &cluster, &offset))
 662                         return false;
 663                 entry_type = EXFAT_ENTRY_FILE_NAME & ~EXFAT_ENTRY_VALID;
 664                 if (exfat_pwrite(ef->dev, &entry_type, 1,
 665                                 co2o(ef, cluster, offset)) < 0)
 666                 {
 667                         exfat_error("failed to erase name entry");
 668                         return false;
 669                 }
 670         }
 671         return true;
 672 }
 673
 674 static int shrink_directory(struct exfat* ef, struct exfat_node* dir,
 675                 off_t deleted_offset)
 676 {
 677         const struct exfat_node* node;
 678         const struct exfat_node* last_node;
 679         uint64_t entries = 0;
 680         uint64_t new_size;
 681
 682         if (!(dir->flags & EXFAT_ATTRIB_DIR))
 683                 exfat_bug("attempted to shrink a file");
 684         if (!(dir->flags & EXFAT_ATTRIB_CACHED))
 685                 exfat_bug("attempted to shrink uncached directory");
 686
 687         for (last_node = node = dir->child; node; node = node->next)
 688         {
 689                 if (deleted_offset < node->entry_offset)
 690                 {
 691                         /* there are other entries after the removed one, no way to shrink
 692                            this directory */
 693                         return 0;
 694                 }
 695                 if (last_node->entry_offset < node->entry_offset)
 696                         last_node = node;
 697         }
 698
 699         if (last_node)
 700         {
 701                 /* offset of the last entry */
 702                 entries += last_node->entry_offset / sizeof(struct exfat_entry);
 703                 /* two subentries with meta info */
 704                 entries += 2;
 705                 /* subentries with file name */
 706                 entries += DIV_ROUND_UP(utf16_length(last_node->name),
 707                                 EXFAT_ENAME_MAX);
 708         }
 709
 710         new_size = DIV_ROUND_UP(entries * sizeof(struct exfat_entry),
 711                                  CLUSTER_SIZE(*ef->sb)) * CLUSTER_SIZE(*ef->sb);
 712         if (new_size == 0) /* directory always has at least 1 cluster */
 713                 new_size = CLUSTER_SIZE(*ef->sb);
 714         if (new_size == dir->size)
 715                 return 0;
 716         return exfat_truncate(ef, dir, new_size, true);
 717 }
 718
 719 static int delete(struct exfat* ef, struct exfat_node* node)
 720 {
 721         struct exfat_node* parent = node->parent;
 722         off_t deleted_offset = node->entry_offset;
 723         int rc;
 724
 725         exfat_get_node(parent);
 726         if (!erase_entry(ef, node))
 727         {
 728                 exfat_put_node(ef, parent);
 729                 return -EIO;
 730         }
 731         exfat_update_mtime(parent);
 732         tree_detach(node);
 733         rc = shrink_directory(ef, parent, deleted_offset);
 734         exfat_put_node(ef, parent);
 735         /* file clusters will be freed when node reference counter becomes 0 */
 736         node->flags |= EXFAT_ATTRIB_UNLINKED;
 737         return rc;
 738 }
 739
 740 int exfat_unlink(struct exfat* ef, struct exfat_node* node)
 741 {
 742         if (node->flags & EXFAT_ATTRIB_DIR)
 743                 return -EISDIR;
 744         return delete(ef, node);
 745 }
 746
 747 int exfat_rmdir(struct exfat* ef, struct exfat_node* node)
 748 {
 749         if (!(node->flags & EXFAT_ATTRIB_DIR))
 750                 return -ENOTDIR;
 751         /* check that directory is empty */
 752         exfat_cache_directory(ef, node);
 753         if (node->child)
 754                 return -ENOTEMPTY;
 755         return delete(ef, node);
 756 }
 757
 758 static int grow_directory(struct exfat* ef, struct exfat_node* dir,
 759                 uint64_t asize, uint32_t difference)
 760 {
 761         return exfat_truncate(ef, dir,
 762                         DIV_ROUND_UP(asize + difference, CLUSTER_SIZE(*ef->sb))
 763                                 * CLUSTER_SIZE(*ef->sb), true);
 764 }
 765
 766 static int find_slot(struct exfat* ef, struct exfat_node* dir,
 767                 cluster_t* cluster, off_t* offset, int subentries)
 768 {
 769         struct iterator it;
 770         int rc;
 771         const struct exfat_entry* entry;
 772         int contiguous = 0;
 773
 774         rc = opendir(ef, dir, &it);
 775         if (rc != 0)
 776                 return rc;
 777         for (;;)
 778         {
 779                 if (contiguous == 0)
 780                 {
 781                         *cluster = it.cluster;
 782                         *offset = it.offset;
 783                 }
 784                 entry = get_entry_ptr(ef, &it);
 785                 if (entry->type & EXFAT_ENTRY_VALID)
 786                         contiguous = 0;
 787                 else
 788                         contiguous++;
 789                 if (contiguous == subentries)
 790                         break;  /* suitable slot is found */
 791                 if (it.offset + sizeof(struct exfat_entry) >= dir->size)
 792                 {
 793                         rc = grow_directory(ef, dir, dir->size,
 794                                         (subentries - contiguous) * sizeof(struct exfat_entry));
 795                         if (rc != 0)
 796                         {
 797                                 closedir(&it);
 798                                 return rc;
 799                         }
 800                 }
 801                 if (fetch_next_entry(ef, dir, &it) != 0)
 802                 {
 803                         closedir(&it);
 804                         return -EIO;
 805                 }
 806         }
 807         closedir(&it);
 808         return 0;
 809 }
 810
 811 static int write_entry(struct exfat* ef, struct exfat_node* dir,
 812                 const le16_t* name, cluster_t cluster, off_t offset, uint16_t attrib)
 813 {
 814         struct exfat_node* node;
 815         struct exfat_entry_meta1 meta1;
 816         struct exfat_entry_meta2 meta2;
 817         const size_t name_length = utf16_length(name);
 818         const int name_entries = DIV_ROUND_UP(name_length, EXFAT_ENAME_MAX);
 819         int i;
 820
 821         node = allocate_node();
 822         if (node == NULL)
 823                 return -ENOMEM;
 824         node->entry_cluster = cluster;
 825         node->entry_offset = offset;
 826         memcpy(node->name, name, name_length * sizeof(le16_t));
 827
 828         memset(&meta1, 0, sizeof(meta1));
 829         meta1.type = EXFAT_ENTRY_FILE;
 830         meta1.continuations = 1 + name_entries;
 831         meta1.attrib = cpu_to_le16(attrib);
 832         exfat_unix2exfat(time(NULL), &meta1.crdate, &meta1.crtime,
 833                         &meta1.crtime_cs);
 834         meta1.adate = meta1.mdate = meta1.crdate;
 835         meta1.atime = meta1.mtime = meta1.crtime;
 836         meta1.mtime_cs = meta1.crtime_cs; /* there is no atime_cs */
 837
 838         memset(&meta2, 0, sizeof(meta2));
 839         meta2.type = EXFAT_ENTRY_FILE_INFO;
 840         meta2.flags = EXFAT_FLAG_ALWAYS1;
 841         meta2.name_length = name_length;
 842         meta2.name_hash = exfat_calc_name_hash(ef, node->name);
 843         meta2.start_cluster = cpu_to_le32(EXFAT_CLUSTER_FREE);
 844
 845         meta1.checksum = exfat_calc_checksum(&meta1, &meta2, node->name);
 846
 847         if (exfat_pwrite(ef->dev, &meta1, sizeof(meta1),
 848                         co2o(ef, cluster, offset)) < 0)
 849         {
 850                 exfat_error("failed to write meta1 entry");
 851                 return -EIO;
 852         }
 853         if (!next_entry(ef, dir, &cluster, &offset))
 854                 return -EIO;
 855         if (exfat_pwrite(ef->dev, &meta2, sizeof(meta2),
 856                         co2o(ef, cluster, offset)) < 0)
 857         {
 858                 exfat_error("failed to write meta2 entry");
 859                 return -EIO;
 860         }
 861         for (i = 0; i < name_entries; i++)
 862         {
 863                 struct exfat_entry_name name_entry = {EXFAT_ENTRY_FILE_NAME, 0};
 864                 memcpy(name_entry.name, node->name + i * EXFAT_ENAME_MAX,
 865                                 MIN(EXFAT_ENAME_MAX, EXFAT_NAME_MAX - i * EXFAT_ENAME_MAX) *
 866                                 sizeof(le16_t));
 867                 if (!next_entry(ef, dir, &cluster, &offset))
 868                         return -EIO;
 869                 if (exfat_pwrite(ef->dev, &name_entry, sizeof(name_entry),
 870                                 co2o(ef, cluster, offset)) < 0)
 871                 {
 872                         exfat_error("failed to write name entry");
 873                         return -EIO;
 874                 }
 875         }
 876
 877         init_node_meta1(node, &meta1);
 878         init_node_meta2(node, &meta2);
 879
 880         tree_attach(dir, node);
 881         exfat_update_mtime(dir);
 882         return 0;
 883 }
 884
 885 static int create(struct exfat* ef, const char* path, uint16_t attrib)
 886 {
 887         struct exfat_node* dir;
 888         struct exfat_node* existing;
 889         cluster_t cluster = EXFAT_CLUSTER_BAD;
 890         off_t offset = -1;
 891         le16_t name[EXFAT_NAME_MAX + 1];
 892         int rc;
 893
 894         rc = exfat_split(ef, &dir, &existing, name, path);
 895         if (rc != 0)
 896                 return rc;
 897         if (existing != NULL)
 898         {
 899                 exfat_put_node(ef, existing);
 900                 exfat_put_node(ef, dir);
 901                 return -EEXIST;
 902         }
 903
 904         rc = find_slot(ef, dir, &cluster, &offset,
 905                         2 + DIV_ROUND_UP(utf16_length(name), EXFAT_ENAME_MAX));
 906         if (rc != 0)
 907         {
 908                 exfat_put_node(ef, dir);
 909                 return rc;
 910         }
 911         rc = write_entry(ef, dir, name, cluster, offset, attrib);
 912         exfat_put_node(ef, dir);
 913         return rc;
 914 }
 915
 916 int exfat_mknod(struct exfat* ef, const char* path)
 917 {
 918         return create(ef, path, EXFAT_ATTRIB_ARCH);
 919 }
 920
 921 int exfat_mkdir(struct exfat* ef, const char* path)
 922 {
 923         int rc;
 924         struct exfat_node* node;
 925
 926         rc = create(ef, path, EXFAT_ATTRIB_ARCH | EXFAT_ATTRIB_DIR);
 927         if (rc != 0)
 928                 return rc;
 929         rc = exfat_lookup(ef, &node, path);
 930         if (rc != 0)
 931                 return 0;
 932         /* directories always have at least one cluster */
 933         rc = exfat_truncate(ef, node, CLUSTER_SIZE(*ef->sb), true);
 934         if (rc != 0)
 935         {
 936                 delete(ef, node);
 937                 exfat_put_node(ef, node);
 938                 return rc;
 939         }
 940         exfat_put_node(ef, node);
 941         return 0;
 942 }
 943
 944 static int rename_entry(struct exfat* ef, struct exfat_node* dir,
 945                 struct exfat_node* node, const le16_t* name, cluster_t new_cluster,
 946                 off_t new_offset)
 947 {
 948         struct exfat_entry_meta1 meta1;
 949         struct exfat_entry_meta2 meta2;
 950         cluster_t old_cluster = node->entry_cluster;
 951         off_t old_offset = node->entry_offset;
 952         const size_t name_length = utf16_length(name);
 953         const int name_entries = DIV_ROUND_UP(name_length, EXFAT_ENAME_MAX);
 954         int i;
 955
 956         if (exfat_pread(ef->dev, &meta1, sizeof(meta1),
 957                         co2o(ef, old_cluster, old_offset)) < 0)
 958         {
 959                 exfat_error("failed to read meta1 entry on rename");
 960                 return -EIO;
 961         }
 962         if (!next_entry(ef, node->parent, &old_cluster, &old_offset))
 963                 return -EIO;
 964         if (exfat_pread(ef->dev, &meta2, sizeof(meta2),
 965                         co2o(ef, old_cluster, old_offset)) < 0)
 966         {
 967                 exfat_error("failed to read meta2 entry on rename");
 968                 return -EIO;
 969         }
 970         meta1.continuations = 1 + name_entries;
 971         meta2.name_hash = exfat_calc_name_hash(ef, name);
 972         meta2.name_length = name_length;
 973         meta1.checksum = exfat_calc_checksum(&meta1, &meta2, name);
 974
 975         if (!erase_entry(ef, node))
 976                 return -EIO;
 977
 978         node->entry_cluster = new_cluster;
 979         node->entry_offset = new_offset;
 980
 981         if (exfat_pwrite(ef->dev, &meta1, sizeof(meta1),
 982                         co2o(ef, new_cluster, new_offset)) < 0)
 983         {
 984                 exfat_error("failed to write meta1 entry on rename");
 985                 return -EIO;
 986         }
 987         if (!next_entry(ef, dir, &new_cluster, &new_offset))
 988                 return -EIO;
 989         if (exfat_pwrite(ef->dev, &meta2, sizeof(meta2),
 990                         co2o(ef, new_cluster, new_offset)) < 0)
 991         {
 992                 exfat_error("failed to write meta2 entry on rename");
 993                 return -EIO;
 994         }
 995
 996         for (i = 0; i < name_entries; i++)
 997         {
 998                 struct exfat_entry_name name_entry = {EXFAT_ENTRY_FILE_NAME, 0};
 999                 memcpy(name_entry.name, name + i * EXFAT_ENAME_MAX,
1000                                 EXFAT_ENAME_MAX * sizeof(le16_t));
1001                 if (!next_entry(ef, dir, &new_cluster, &new_offset))
1002                         return -EIO;
1003                 if (exfat_pwrite(ef->dev, &name_entry, sizeof(name_entry),
1004                                 co2o(ef, new_cluster, new_offset)) < 0)
1005                 {
1006                         exfat_error("failed to write name entry on rename");
1007                         return -EIO;
1008                 }
1009         }
1010
1011         memcpy(node->name, name, (EXFAT_NAME_MAX + 1) * sizeof(le16_t));
1012         tree_detach(node);
1013         tree_attach(dir, node);
1014         return 0;
1015 }
1016
1017 int exfat_rename(struct exfat* ef, const char* old_path, const char* new_path)
1018 {
1019         struct exfat_node* node;
1020         struct exfat_node* existing;
1021         struct exfat_node* dir;
1022         cluster_t cluster = EXFAT_CLUSTER_BAD;
1023         off_t offset = -1;
1024         le16_t name[EXFAT_NAME_MAX + 1];
1025         int rc;
1026
1027         rc = exfat_lookup(ef, &node, old_path);
1028         if (rc != 0)
1029                 return rc;
1030
1031         rc = exfat_split(ef, &dir, &existing, name, new_path);
1032         if (rc != 0)
1033         {
1034                 exfat_put_node(ef, node);
1035                 return rc;
1036         }
1037
1038         /* check that target is not a subdirectory of the source */
1039         if (node->flags & EXFAT_ATTRIB_DIR)
1040         {
1041                 struct exfat_node* p;
1042
1043                 for (p = dir; p; p = p->parent)
1044                         if (node == p)
1045                         {
1046                                 if (existing != NULL)
1047                                         exfat_put_node(ef, existing);
1048                                 exfat_put_node(ef, dir);
1049                                 exfat_put_node(ef, node);
1050                                 return -EINVAL;
1051                         }
1052         }
1053
1054         if (existing != NULL)
1055         {
1056                 /* remove target if it's not the same node as source */
1057                 if (existing != node)
1058                 {
1059                         if (existing->flags & EXFAT_ATTRIB_DIR)
1060                         {
1061                                 if (node->flags & EXFAT_ATTRIB_DIR)
1062                                         rc = exfat_rmdir(ef, existing);
1063                                 else
1064                                         rc = -ENOTDIR;
1065                         }
1066                         else
1067                         {
1068                                 if (!(node->flags & EXFAT_ATTRIB_DIR))
1069                                         rc = exfat_unlink(ef, existing);
1070                                 else
1071                                         rc = -EISDIR;
1072                         }
1073                         exfat_put_node(ef, existing);
1074                         if (rc != 0)
1075                         {
1076                                 exfat_put_node(ef, dir);
1077                                 exfat_put_node(ef, node);
1078                                 return rc;
1079                         }
1080                 }
1081                 else
1082                         exfat_put_node(ef, existing);
1083         }
1084
1085         rc = find_slot(ef, dir, &cluster, &offset,
1086                         2 + DIV_ROUND_UP(utf16_length(name), EXFAT_ENAME_MAX));
1087         if (rc != 0)
1088         {
1089                 exfat_put_node(ef, dir);
1090                 exfat_put_node(ef, node);
1091                 return rc;
1092         }
1093         rc = rename_entry(ef, dir, node, name, cluster, offset);
1094         exfat_put_node(ef, dir);
1095         exfat_put_node(ef, node);
1096         return 0;
1097 }
1098
1099 void exfat_utimes(struct exfat_node* node, const struct timespec tv[2])
1100 {
1101         node->atime = tv[0].tv_sec;
1102         node->mtime = tv[1].tv_sec;
1103         node->flags |= EXFAT_ATTRIB_DIRTY;
1104 }
1105
1106 void exfat_update_atime(struct exfat_node* node)
1107 {
1108         node->atime = time(NULL);
1109         node->flags |= EXFAT_ATTRIB_DIRTY;
1110 }
1111
1112 void exfat_update_mtime(struct exfat_node* node)
1113 {
1114         node->mtime = time(NULL);
1115         node->flags |= EXFAT_ATTRIB_DIRTY;
1116 }
1117
1118 const char* exfat_get_label(struct exfat* ef)
1119 {
1120         return ef->label;
1121 }
1122
1123 static int find_label(struct exfat* ef, cluster_t* cluster, off_t* offset)
1124 {
1125         struct iterator it;
1126         int rc;
1127
1128         rc = opendir(ef, ef->root, &it);
1129         if (rc != 0)
1130                 return rc;
1131
1132         for (;;)
1133         {
1134                 if (it.offset >= ef->root->size)
1135                 {
1136                         closedir(&it);
1137                         return -ENOENT;
1138                 }
1139
1140                 if (get_entry_ptr(ef, &it)->type == EXFAT_ENTRY_LABEL)
1141                 {
1142                         *cluster = it.cluster;
1143                         *offset = it.offset;
1144                         closedir(&it);
1145                         return 0;
1146                 }
1147
1148                 if (fetch_next_entry(ef, ef->root, &it) != 0)
1149                 {
1150                         closedir(&it);
1151                         return -EIO;
1152                 }
1153         }
1154 }
1155
1156 int exfat_set_label(struct exfat* ef, const char* label)
1157 {
1158         le16_t label_utf16[EXFAT_ENAME_MAX + 1];
1159         int rc;
1160         cluster_t cluster;
1161         off_t offset;
1162         struct exfat_entry_label entry;
1163
1164         memset(label_utf16, 0, sizeof(label_utf16));
1165         rc = utf8_to_utf16(label_utf16, label, EXFAT_ENAME_MAX, strlen(label));
1166         if (rc != 0)
1167                 return rc;
1168
1169         rc = find_label(ef, &cluster, &offset);
1170         if (rc == -ENOENT)
1171                 rc = find_slot(ef, ef->root, &cluster, &offset, 1);
1172         if (rc != 0)
1173                 return rc;
1174
1175         entry.type = EXFAT_ENTRY_LABEL;
1176         entry.length = utf16_length(label_utf16);
1177         memcpy(entry.name, label_utf16, sizeof(entry.name));
1178         if (entry.length == 0)
1179                 entry.type ^= EXFAT_ENTRY_VALID;
1180
1181         if (exfat_pwrite(ef->dev, &entry, sizeof(struct exfat_entry_label),
1182                         co2o(ef, cluster, offset)) < 0)
1183         {
1184                 exfat_error("failed to write label entry");
1185                 return -EIO;
1186         }
1187         strcpy(ef->label, label);
1188         return 0;
1189 }