node.c

   1 /*
   2         node.c (09.10.09)
   3         exFAT file system implementation library.
   4
   5         Free exFAT implementation.
   6         Copyright (C) 2010-2016  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         char buffer[UTF8_BYTES(EXFAT_NAME_MAX) + 1];
  48
  49         --node->references;
  50         if (node->references < 0)
  51         {
  52                 exfat_get_name(node, buffer, sizeof(buffer) - 1);
  53                 exfat_bug("reference counter of '%s' is below zero", buffer);
  54         }
  55         else if (node->references == 0 && node != ef->root)
  56         {
  57                 if (node->flags & EXFAT_ATTRIB_DIRTY)
  58                 {
  59                         exfat_get_name(node, buffer, sizeof(buffer) - 1);
  60                         exfat_warn("dirty node '%s' with zero references", buffer);
  61                 }
  62         }
  63 }
  64
  65 /**
  66  * This function must be called on rmdir and unlink (after the last
  67  * exfat_put_node()) to free clusters.
  68  */
  69 int exfat_cleanup_node(struct exfat* ef, struct exfat_node* node)
  70 {
  71         int rc = 0;
  72
  73         if (node->references != 0)
  74                 exfat_bug("unable to cleanup a node with %d references",
  75                                 node->references);
  76
  77         if (node->flags & EXFAT_ATTRIB_UNLINKED)
  78         {
  79                 /* free all clusters and node structure itself */
  80                 rc = exfat_truncate(ef, node, 0, true);
  81                 /* free the node even in case of error or its memory will be lost */
  82                 free(node);
  83         }
  84         return rc;
  85 }
  86
  87 /**
  88  * Cluster + offset from the beginning of the directory to absolute offset.
  89  */
  90 static off_t co2o(struct exfat* ef, cluster_t cluster, off_t offset)
  91 {
  92         return exfat_c2o(ef, cluster) + offset % CLUSTER_SIZE(*ef->sb);
  93 }
  94
  95 static int opendir(struct exfat* ef, const struct exfat_node* dir,
  96                 struct iterator* it)
  97 {
  98         if (!(dir->flags & EXFAT_ATTRIB_DIR))
  99                 exfat_bug("not a directory");
 100         it->cluster = dir->start_cluster;
 101         it->offset = 0;
 102         it->contiguous = IS_CONTIGUOUS(*dir);
 103         it->chunk = malloc(CLUSTER_SIZE(*ef->sb));
 104         if (it->chunk == NULL)
 105         {
 106                 exfat_error("out of memory");
 107                 return -ENOMEM;
 108         }
 109         if (exfat_pread(ef->dev, it->chunk, CLUSTER_SIZE(*ef->sb),
 110                         exfat_c2o(ef, it->cluster)) < 0)
 111         {
 112                 exfat_error("failed to read directory cluster %#x", it->cluster);
 113                 return -EIO;
 114         }
 115         return 0;
 116 }
 117
 118 static void closedir(struct iterator* it)
 119 {
 120         it->cluster = 0;
 121         it->offset = 0;
 122         it->contiguous = 0;
 123         free(it->chunk);
 124         it->chunk = NULL;
 125 }
 126
 127 static bool fetch_next_entry(struct exfat* ef, const struct exfat_node* parent,
 128                 struct iterator* it)
 129 {
 130         /* move iterator to the next entry in the directory */
 131         it->offset += sizeof(struct exfat_entry);
 132         /* fetch the next cluster if needed */
 133         if ((it->offset & (CLUSTER_SIZE(*ef->sb) - 1)) == 0)
 134         {
 135                 /* reached the end of directory; the caller should check this
 136                    condition too */
 137                 if (it->offset >= parent->size)
 138                         return true;
 139                 it->cluster = exfat_next_cluster(ef, parent, it->cluster);
 140                 if (CLUSTER_INVALID(it->cluster))
 141                 {
 142                         exfat_error("invalid cluster 0x%x while reading directory",
 143                                         it->cluster);
 144                         return false;
 145                 }
 146                 if (exfat_pread(ef->dev, it->chunk, CLUSTER_SIZE(*ef->sb),
 147                                 exfat_c2o(ef, it->cluster)) < 0)
 148                 {
 149                         exfat_error("failed to read the next directory cluster %#x",
 150                                         it->cluster);
 151                         return false;
 152                 }
 153         }
 154         return true;
 155 }
 156
 157 static struct exfat_node* allocate_node(void)
 158 {
 159         struct exfat_node* node = malloc(sizeof(struct exfat_node));
 160         if (node == NULL)
 161         {
 162                 exfat_error("failed to allocate node");
 163                 return NULL;
 164         }
 165         memset(node, 0, sizeof(struct exfat_node));
 166         return node;
 167 }
 168
 169 static void init_node_meta1(struct exfat_node* node,
 170                 const struct exfat_entry_meta1* meta1)
 171 {
 172         node->flags = le16_to_cpu(meta1->attrib);
 173         node->mtime = exfat_exfat2unix(meta1->mdate, meta1->mtime,
 174                         meta1->mtime_cs);
 175         /* there is no centiseconds field for atime */
 176         node->atime = exfat_exfat2unix(meta1->adate, meta1->atime, 0);
 177 }
 178
 179 static void init_node_meta2(struct exfat_node* node,
 180                 const struct exfat_entry_meta2* meta2)
 181 {
 182         node->size = le64_to_cpu(meta2->size);
 183         node->start_cluster = le32_to_cpu(meta2->start_cluster);
 184         node->fptr_cluster = node->start_cluster;
 185         if (meta2->flags & EXFAT_FLAG_CONTIGUOUS)
 186                 node->flags |= EXFAT_ATTRIB_CONTIGUOUS;
 187 }
 188
 189 static const struct exfat_entry* get_entry_ptr(const struct exfat* ef,
 190                 const struct iterator* it)
 191 {
 192         return (const struct exfat_entry*)
 193                         (it->chunk + it->offset % CLUSTER_SIZE(*ef->sb));
 194 }
 195
 196 static bool check_node(const struct exfat_node* node, uint16_t actual_checksum,
 197                 uint16_t reference_checksum, uint64_t valid_size)
 198 {
 199         char buffer[UTF8_BYTES(EXFAT_NAME_MAX) + 1];
 200
 201         /*
 202            Validate checksum first. If it's invalid all other fields probably
 203            contain just garbage.
 204         */
 205         if (actual_checksum != reference_checksum)
 206         {
 207                 exfat_get_name(node, buffer, sizeof(buffer) - 1);
 208                 exfat_error("'%s' has invalid checksum (%#hx != %#hx)", buffer,
 209                                 actual_checksum, reference_checksum);
 210                 return false;
 211         }
 212
 213         /*
 214            exFAT does not support sparse files but allows files with uninitialized
 215            clusters. For such files valid_size means initialized data size and
 216            cannot be greater than file size. See SetFileValidData() function
 217            description in MSDN.
 218         */
 219         if (valid_size > node->size)
 220         {
 221                 exfat_get_name(node, buffer, sizeof(buffer) - 1);
 222                 exfat_error("'%s' has valid size (%"PRIu64") greater than size "
 223                                 "(%"PRIu64")", buffer, valid_size, node->size);
 224                 return false;
 225         }
 226
 227         return true;
 228 }
 229
 230 static void decompress_upcase(uint16_t* output, const le16_t* source,
 231                 size_t size)
 232 {
 233         size_t si;
 234         size_t oi;
 235
 236         for (oi = 0; oi < EXFAT_UPCASE_CHARS; oi++)
 237                 output[oi] = oi;
 238
 239         for (si = 0, oi = 0; si < size && oi < EXFAT_UPCASE_CHARS; si++)
 240         {
 241                 uint16_t ch = le16_to_cpu(source[si]);
 242
 243                 if (ch == 0xffff && si + 1 < size)      /* indicates a run */
 244                         oi += le16_to_cpu(source[++si]);
 245                 else
 246                         output[oi++] = ch;
 247         }
 248 }
 249
 250 /*
 251  * Reads one entry in directory at position pointed by iterator and fills
 252  * node structure.
 253  */
 254 static int readdir(struct exfat* ef, const struct exfat_node* parent,
 255                 struct exfat_node** node, struct iterator* it)
 256 {
 257         int rc = -EIO;
 258         const struct exfat_entry* entry;
 259         const struct exfat_entry_meta1* meta1;
 260         const struct exfat_entry_meta2* meta2;
 261         const struct exfat_entry_name* file_name;
 262         const struct exfat_entry_upcase* upcase;
 263         const struct exfat_entry_bitmap* bitmap;
 264         const struct exfat_entry_label* label;
 265         uint8_t continuations = 0;
 266         le16_t* namep = NULL;
 267         uint16_t reference_checksum = 0;
 268         uint16_t actual_checksum = 0;
 269         uint64_t valid_size = 0;
 270         uint64_t upcase_size = 0;
 271         le16_t* upcase_comp = NULL;
 272
 273         *node = NULL;
 274
 275         for (;;)
 276         {
 277                 if (it->offset >= parent->size)
 278                 {
 279                         if (continuations != 0)
 280                         {
 281                                 exfat_error("expected %hhu continuations", continuations);
 282                                 goto error;
 283                         }
 284                         return -ENOENT; /* that's OK, means end of directory */
 285                 }
 286
 287                 entry = get_entry_ptr(ef, it);
 288                 switch (entry->type)
 289                 {
 290                 case EXFAT_ENTRY_FILE:
 291                         if (continuations != 0)
 292                         {
 293                                 exfat_error("expected %hhu continuations before new entry",
 294                                                 continuations);
 295                                 goto error;
 296                         }
 297                         meta1 = (const struct exfat_entry_meta1*) entry;
 298                         continuations = meta1->continuations;
 299                         /* each file entry must have at least 2 continuations:
 300                            info and name */
 301                         if (continuations < 2)
 302                         {
 303                                 exfat_error("too few continuations (%hhu)", continuations);
 304                                 goto error;
 305                         }
 306                         if (continuations > 1 +
 307                                         DIV_ROUND_UP(EXFAT_NAME_MAX, EXFAT_ENAME_MAX))
 308                         {
 309                                 exfat_error("too many continuations (%hhu)", continuations);
 310                                 goto error;
 311                         }
 312                         reference_checksum = le16_to_cpu(meta1->checksum);
 313                         actual_checksum = exfat_start_checksum(meta1);
 314                         *node = allocate_node();
 315                         if (*node == NULL)
 316                         {
 317                                 rc = -ENOMEM;
 318                                 goto error;
 319                         }
 320                         /* new node has zero reference counter */
 321                         (*node)->entry_cluster = it->cluster;
 322                         (*node)->entry_offset = it->offset;
 323                         init_node_meta1(*node, meta1);
 324                         namep = (*node)->name;
 325                         break;
 326
 327                 case EXFAT_ENTRY_FILE_INFO:
 328                         if (continuations < 2)
 329                         {
 330                                 exfat_error("unexpected continuation (%hhu)",
 331                                                 continuations);
 332                                 goto error;
 333                         }
 334                         meta2 = (const struct exfat_entry_meta2*) entry;
 335                         if (meta2->flags & ~(EXFAT_FLAG_ALWAYS1 | EXFAT_FLAG_CONTIGUOUS))
 336                         {
 337                                 exfat_error("unknown flags in meta2 (0x%hhx)", meta2->flags);
 338                                 goto error;
 339                         }
 340                         init_node_meta2(*node, meta2);
 341                         actual_checksum = exfat_add_checksum(entry, actual_checksum);
 342                         valid_size = le64_to_cpu(meta2->valid_size);
 343                         /* empty files must be marked as non-contiguous */
 344                         if ((*node)->size == 0 && (meta2->flags & EXFAT_FLAG_CONTIGUOUS))
 345                         {
 346                                 exfat_error("empty file marked as contiguous (0x%hhx)",
 347                                                 meta2->flags);
 348                                 goto error;
 349                         }
 350                         /* directories must be aligned on at cluster boundary */
 351                         if (((*node)->flags & EXFAT_ATTRIB_DIR) &&
 352                                 (*node)->size % CLUSTER_SIZE(*ef->sb) != 0)
 353                         {
 354                                 exfat_error("directory has invalid size %"PRIu64" bytes",
 355                                                 (*node)->size);
 356                                 goto error;
 357                         }
 358                         --continuations;
 359                         break;
 360
 361                 case EXFAT_ENTRY_FILE_NAME:
 362                         if (continuations == 0)
 363                         {
 364                                 exfat_error("unexpected continuation");
 365                                 goto error;
 366                         }
 367                         file_name = (const struct exfat_entry_name*) entry;
 368                         actual_checksum = exfat_add_checksum(entry, actual_checksum);
 369
 370                         memcpy(namep, file_name->name,
 371                                         MIN(EXFAT_ENAME_MAX,
 372                                                 ((*node)->name + EXFAT_NAME_MAX - namep)) *
 373                                         sizeof(le16_t));
 374                         namep += EXFAT_ENAME_MAX;
 375                         if (--continuations == 0)
 376                         {
 377                                 if (!check_node(*node, actual_checksum, reference_checksum,
 378                                                 valid_size))
 379                                         goto error;
 380                                 if (!fetch_next_entry(ef, parent, it))
 381                                         goto error;
 382                                 return 0; /* entry completed */
 383                         }
 384                         break;
 385
 386                 case EXFAT_ENTRY_UPCASE:
 387                         if (ef->upcase != NULL)
 388                                 break;
 389                         upcase = (const struct exfat_entry_upcase*) entry;
 390                         if (CLUSTER_INVALID(le32_to_cpu(upcase->start_cluster)))
 391                         {
 392                                 exfat_error("invalid cluster 0x%x in upcase table",
 393                                                 le32_to_cpu(upcase->start_cluster));
 394                                 goto error;
 395                         }
 396                         upcase_size = le64_to_cpu(upcase->size);
 397                         if (upcase_size == 0 ||
 398                                 upcase_size > EXFAT_UPCASE_CHARS * sizeof(uint16_t) ||
 399                                 upcase_size % sizeof(uint16_t) != 0)
 400                         {
 401                                 exfat_error("bad upcase table size (%"PRIu64" bytes)",
 402                                                 upcase_size);
 403                                 goto error;
 404                         }
 405                         upcase_comp = malloc(upcase_size);
 406                         if (upcase_comp == NULL)
 407                         {
 408                                 exfat_error("failed to allocate upcase table (%"PRIu64" bytes)",
 409                                                 upcase_size);
 410                                 rc = -ENOMEM;
 411                                 goto error;
 412                         }
 413
 414                         /* read compressed upcase table */
 415                         if (exfat_pread(ef->dev, upcase_comp, upcase_size,
 416                                         exfat_c2o(ef, le32_to_cpu(upcase->start_cluster))) < 0)
 417                         {
 418                                 free(upcase_comp);
 419                                 exfat_error("failed to read upper case table "
 420                                                 "(%"PRIu64" bytes starting at cluster %#x)",
 421                                                 upcase_size,
 422                                                 le32_to_cpu(upcase->start_cluster));
 423                                 goto error;
 424                         }
 425
 426                         /* decompress upcase table */
 427                         ef->upcase = calloc(EXFAT_UPCASE_CHARS, sizeof(uint16_t));
 428                         if (ef->upcase == NULL)
 429                         {
 430                                 free(upcase_comp);
 431                                 exfat_error("failed to allocate decompressed upcase table");
 432                                 rc = -ENOMEM;
 433                                 goto error;
 434                         }
 435                         decompress_upcase(ef->upcase, upcase_comp,
 436                                         upcase_size / sizeof(uint16_t));
 437                         free(upcase_comp);
 438                         break;
 439
 440                 case EXFAT_ENTRY_BITMAP:
 441                         bitmap = (const struct exfat_entry_bitmap*) entry;
 442                         ef->cmap.start_cluster = le32_to_cpu(bitmap->start_cluster);
 443                         if (CLUSTER_INVALID(ef->cmap.start_cluster))
 444                         {
 445                                 exfat_error("invalid cluster 0x%x in clusters bitmap",
 446                                                 ef->cmap.start_cluster);
 447                                 goto error;
 448                         }
 449                         ef->cmap.size = le32_to_cpu(ef->sb->cluster_count) -
 450                                 EXFAT_FIRST_DATA_CLUSTER;
 451                         if (le64_to_cpu(bitmap->size) < DIV_ROUND_UP(ef->cmap.size, 8))
 452                         {
 453                                 exfat_error("invalid clusters bitmap size: %"PRIu64
 454                                                 " (expected at least %u)",
 455                                                 le64_to_cpu(bitmap->size),
 456                                                 DIV_ROUND_UP(ef->cmap.size, 8));
 457                                 goto error;
 458                         }
 459                         /* FIXME bitmap can be rather big, up to 512 MB */
 460                         ef->cmap.chunk_size = ef->cmap.size;
 461                         ef->cmap.chunk = malloc(BMAP_SIZE(ef->cmap.chunk_size));
 462                         if (ef->cmap.chunk == NULL)
 463                         {
 464                                 exfat_error("failed to allocate clusters bitmap chunk "
 465                                                 "(%"PRIu64" bytes)", le64_to_cpu(bitmap->size));
 466                                 rc = -ENOMEM;
 467                                 goto error;
 468                         }
 469
 470                         if (exfat_pread(ef->dev, ef->cmap.chunk,
 471                                         BMAP_SIZE(ef->cmap.chunk_size),
 472                                         exfat_c2o(ef, ef->cmap.start_cluster)) < 0)
 473                         {
 474                                 exfat_error("failed to read clusters bitmap "
 475                                                 "(%"PRIu64" bytes starting at cluster %#x)",
 476                                                 le64_to_cpu(bitmap->size), ef->cmap.start_cluster);
 477                                 goto error;
 478                         }
 479                         break;
 480
 481                 case EXFAT_ENTRY_LABEL:
 482                         label = (const struct exfat_entry_label*) entry;
 483                         if (label->length > EXFAT_ENAME_MAX)
 484                         {
 485                                 exfat_error("too long label (%hhu chars)", label->length);
 486                                 goto error;
 487                         }
 488                         if (utf16_to_utf8(ef->label, label->name,
 489                                                 sizeof(ef->label) - 1, EXFAT_ENAME_MAX) != 0)
 490                                 goto error;
 491                         break;
 492
 493                 default:
 494                         if (!(entry->type & EXFAT_ENTRY_VALID))
 495                                 break; /* deleted entry, ignore it */
 496                         if (!(entry->type & EXFAT_ENTRY_OPTIONAL))
 497                         {
 498                                 exfat_error("unknown entry type %#hhx", entry->type);
 499                                 goto error;
 500                         }
 501                         /* optional entry, warn and skip */
 502                         exfat_warn("unknown entry type %#hhx", entry->type);
 503                         if (continuations == 0)
 504                         {
 505                                 exfat_error("unexpected continuation");
 506                                 goto error;
 507                         }
 508                         --continuations;
 509                         break;
 510                 }
 511
 512                 if (!fetch_next_entry(ef, parent, it))
 513                         goto error;
 514         }
 515         /* we never reach here */
 516
 517 error:
 518         free(*node);
 519         *node = NULL;
 520         return rc;
 521 }
 522
 523 int exfat_cache_directory(struct exfat* ef, struct exfat_node* dir)
 524 {
 525         struct iterator it;
 526         int rc;
 527         struct exfat_node* node;
 528         struct exfat_node* current = NULL;
 529
 530         if (dir->flags & EXFAT_ATTRIB_CACHED)
 531                 return 0; /* already cached */
 532
 533         rc = opendir(ef, dir, &it);
 534         if (rc != 0)
 535                 return rc;
 536         while ((rc = readdir(ef, dir, &node, &it)) == 0)
 537         {
 538                 node->parent = dir;
 539                 if (current != NULL)
 540                 {
 541                         current->next = node;
 542                         node->prev = current;
 543                 }
 544                 else
 545                         dir->child = node;
 546
 547                 current = node;
 548         }
 549         closedir(&it);
 550
 551         if (rc != -ENOENT)
 552         {
 553                 /* rollback */
 554                 for (current = dir->child; current; current = node)
 555                 {
 556                         node = current->next;
 557                         free(current);
 558                 }
 559                 dir->child = NULL;
 560                 return rc;
 561         }
 562
 563         dir->flags |= EXFAT_ATTRIB_CACHED;
 564         return 0;
 565 }
 566
 567 static void tree_attach(struct exfat_node* dir, struct exfat_node* node)
 568 {
 569         node->parent = dir;
 570         if (dir->child)
 571         {
 572                 dir->child->prev = node;
 573                 node->next = dir->child;
 574         }
 575         dir->child = node;
 576 }
 577
 578 static void tree_detach(struct exfat_node* node)
 579 {
 580         if (node->prev)
 581                 node->prev->next = node->next;
 582         else /* this is the first node in the list */
 583                 node->parent->child = node->next;
 584         if (node->next)
 585                 node->next->prev = node->prev;
 586         node->parent = NULL;
 587         node->prev = NULL;
 588         node->next = NULL;
 589 }
 590
 591 static void reset_cache(struct exfat* ef, struct exfat_node* node)
 592 {
 593         char buffer[UTF8_BYTES(EXFAT_NAME_MAX) + 1];
 594
 595         while (node->child)
 596         {
 597                 struct exfat_node* p = node->child;
 598                 reset_cache(ef, p);
 599                 tree_detach(p);
 600                 free(p);
 601         }
 602         node->flags &= ~EXFAT_ATTRIB_CACHED;
 603         if (node->references != 0)
 604         {
 605                 exfat_get_name(node, buffer, sizeof(buffer) - 1);
 606                 exfat_warn("non-zero reference counter (%d) for '%s'",
 607                                 node->references, buffer);
 608         }
 609         if (node != ef->root && (node->flags & EXFAT_ATTRIB_DIRTY))
 610         {
 611                 exfat_get_name(node, buffer, sizeof(buffer) - 1);
 612                 exfat_bug("node '%s' is dirty", buffer);
 613         }
 614         while (node->references)
 615                 exfat_put_node(ef, node);
 616 }
 617
 618 void exfat_reset_cache(struct exfat* ef)
 619 {
 620         reset_cache(ef, ef->root);
 621 }
 622
 623 static bool next_entry(struct exfat* ef, const struct exfat_node* parent,
 624                 cluster_t* cluster, off_t* offset)
 625 {
 626         *offset += sizeof(struct exfat_entry);
 627         if (*offset % CLUSTER_SIZE(*ef->sb) == 0)
 628         {
 629                 *cluster = exfat_next_cluster(ef, parent, *cluster);
 630                 if (CLUSTER_INVALID(*cluster))
 631                 {
 632                         exfat_error("invalid cluster %#x while getting next entry",
 633                                         *cluster);
 634                         return false;
 635                 }
 636         }
 637         return true;
 638 }
 639
 640 int exfat_flush_node(struct exfat* ef, struct exfat_node* node)
 641 {
 642         cluster_t cluster;
 643         off_t offset;
 644         off_t meta1_offset, meta2_offset;
 645         struct exfat_entry_meta1 meta1;
 646         struct exfat_entry_meta2 meta2;
 647
 648         if (!(node->flags & EXFAT_ATTRIB_DIRTY))
 649                 return 0; /* no need to flush */
 650
 651         if (ef->ro)
 652                 exfat_bug("unable to flush node to read-only FS");
 653
 654         if (node->parent == NULL)
 655                 return 0; /* do not flush unlinked node */
 656
 657         cluster = node->entry_cluster;
 658         offset = node->entry_offset;
 659         meta1_offset = co2o(ef, cluster, offset);
 660         if (!next_entry(ef, node->parent, &cluster, &offset))
 661                 return -EIO;
 662         meta2_offset = co2o(ef, cluster, offset);
 663
 664         if (exfat_pread(ef->dev, &meta1, sizeof(meta1), meta1_offset) < 0)
 665         {
 666                 exfat_error("failed to read meta1 entry on flush");
 667                 return -EIO;
 668         }
 669         if (meta1.type != EXFAT_ENTRY_FILE)
 670                 exfat_bug("invalid type of meta1: 0x%hhx", meta1.type);
 671         meta1.attrib = cpu_to_le16(node->flags);
 672         exfat_unix2exfat(node->mtime, &meta1.mdate, &meta1.mtime, &meta1.mtime_cs);
 673         exfat_unix2exfat(node->atime, &meta1.adate, &meta1.atime, NULL);
 674
 675         if (exfat_pread(ef->dev, &meta2, sizeof(meta2), meta2_offset) < 0)
 676         {
 677                 exfat_error("failed to read meta2 entry on flush");
 678                 return -EIO;
 679         }
 680         if (meta2.type != EXFAT_ENTRY_FILE_INFO)
 681                 exfat_bug("invalid type of meta2: 0x%hhx", meta2.type);
 682         meta2.size = meta2.valid_size = cpu_to_le64(node->size);
 683         meta2.start_cluster = cpu_to_le32(node->start_cluster);
 684         meta2.flags = EXFAT_FLAG_ALWAYS1;
 685         /* empty files must not be marked as contiguous */
 686         if (node->size != 0 && IS_CONTIGUOUS(*node))
 687                 meta2.flags |= EXFAT_FLAG_CONTIGUOUS;
 688         /* name hash remains unchanged, no need to recalculate it */
 689
 690         meta1.checksum = exfat_calc_checksum(&meta1, &meta2, node->name);
 691
 692         if (exfat_pwrite(ef->dev, &meta1, sizeof(meta1), meta1_offset) < 0)
 693         {
 694                 exfat_error("failed to write meta1 entry on flush");
 695                 return -EIO;
 696         }
 697         if (exfat_pwrite(ef->dev, &meta2, sizeof(meta2), meta2_offset) < 0)
 698         {
 699                 exfat_error("failed to write meta2 entry on flush");
 700                 return -EIO;
 701         }
 702
 703         node->flags &= ~EXFAT_ATTRIB_DIRTY;
 704         return exfat_flush(ef);
 705 }
 706
 707 static bool erase_entry(struct exfat* ef, struct exfat_node* node)
 708 {
 709         cluster_t cluster = node->entry_cluster;
 710         off_t offset = node->entry_offset;
 711         int name_entries = DIV_ROUND_UP(utf16_length(node->name), EXFAT_ENAME_MAX);
 712         uint8_t entry_type;
 713
 714         entry_type = EXFAT_ENTRY_FILE & ~EXFAT_ENTRY_VALID;
 715         if (exfat_pwrite(ef->dev, &entry_type, 1, co2o(ef, cluster, offset)) < 0)
 716         {
 717                 exfat_error("failed to erase meta1 entry");
 718                 return false;
 719         }
 720
 721         if (!next_entry(ef, node->parent, &cluster, &offset))
 722                 return false;
 723         entry_type = EXFAT_ENTRY_FILE_INFO & ~EXFAT_ENTRY_VALID;
 724         if (exfat_pwrite(ef->dev, &entry_type, 1, co2o(ef, cluster, offset)) < 0)
 725         {
 726                 exfat_error("failed to erase meta2 entry");
 727                 return false;
 728         }
 729
 730         while (name_entries--)
 731         {
 732                 if (!next_entry(ef, node->parent, &cluster, &offset))
 733                         return false;
 734                 entry_type = EXFAT_ENTRY_FILE_NAME & ~EXFAT_ENTRY_VALID;
 735                 if (exfat_pwrite(ef->dev, &entry_type, 1,
 736                                 co2o(ef, cluster, offset)) < 0)
 737                 {
 738                         exfat_error("failed to erase name entry");
 739                         return false;
 740                 }
 741         }
 742         return true;
 743 }
 744
 745 static int shrink_directory(struct exfat* ef, struct exfat_node* dir,
 746                 off_t deleted_offset)
 747 {
 748         const struct exfat_node* node;
 749         const struct exfat_node* last_node;
 750         uint64_t entries = 0;
 751         uint64_t new_size;
 752
 753         if (!(dir->flags & EXFAT_ATTRIB_DIR))
 754                 exfat_bug("attempted to shrink a file");
 755         if (!(dir->flags & EXFAT_ATTRIB_CACHED))
 756                 exfat_bug("attempted to shrink uncached directory");
 757
 758         for (last_node = node = dir->child; node; node = node->next)
 759         {
 760                 if (deleted_offset < node->entry_offset)
 761                 {
 762                         /* there are other entries after the removed one, no way to shrink
 763                            this directory */
 764                         return 0;
 765                 }
 766                 if (last_node->entry_offset < node->entry_offset)
 767                         last_node = node;
 768         }
 769
 770         if (last_node)
 771         {
 772                 /* offset of the last entry */
 773                 entries += last_node->entry_offset / sizeof(struct exfat_entry);
 774                 /* two subentries with meta info */
 775                 entries += 2;
 776                 /* subentries with file name */
 777                 entries += DIV_ROUND_UP(utf16_length(last_node->name),
 778                                 EXFAT_ENAME_MAX);
 779         }
 780
 781         new_size = DIV_ROUND_UP(entries * sizeof(struct exfat_entry),
 782                                  CLUSTER_SIZE(*ef->sb)) * CLUSTER_SIZE(*ef->sb);
 783         if (new_size == 0) /* directory always has at least 1 cluster */
 784                 new_size = CLUSTER_SIZE(*ef->sb);
 785         if (new_size == dir->size)
 786                 return 0;
 787         return exfat_truncate(ef, dir, new_size, true);
 788 }
 789
 790 static int delete(struct exfat* ef, struct exfat_node* node)
 791 {
 792         struct exfat_node* parent = node->parent;
 793         off_t deleted_offset = node->entry_offset;
 794         int rc;
 795
 796         exfat_get_node(parent);
 797         if (!erase_entry(ef, node))
 798         {
 799                 exfat_put_node(ef, parent);
 800                 return -EIO;
 801         }
 802         exfat_update_mtime(parent);
 803         tree_detach(node);
 804         rc = shrink_directory(ef, parent, deleted_offset);
 805         node->flags |= EXFAT_ATTRIB_UNLINKED;
 806         if (rc != 0)
 807         {
 808                 exfat_flush_node(ef, parent);
 809                 exfat_put_node(ef, parent);
 810                 return rc;
 811         }
 812         rc = exfat_flush_node(ef, parent);
 813         exfat_put_node(ef, parent);
 814         return rc;
 815 }
 816
 817 int exfat_unlink(struct exfat* ef, struct exfat_node* node)
 818 {
 819         if (node->flags & EXFAT_ATTRIB_DIR)
 820                 return -EISDIR;
 821         return delete(ef, node);
 822 }
 823
 824 int exfat_rmdir(struct exfat* ef, struct exfat_node* node)
 825 {
 826         int rc;
 827
 828         if (!(node->flags & EXFAT_ATTRIB_DIR))
 829                 return -ENOTDIR;
 830         /* check that directory is empty */
 831         rc = exfat_cache_directory(ef, node);
 832         if (rc != 0)
 833                 return rc;
 834         if (node->child)
 835                 return -ENOTEMPTY;
 836         return delete(ef, node);
 837 }
 838
 839 static int grow_directory(struct exfat* ef, struct exfat_node* dir,
 840                 uint64_t asize, uint32_t difference)
 841 {
 842         return exfat_truncate(ef, dir,
 843                         DIV_ROUND_UP(asize + difference, CLUSTER_SIZE(*ef->sb))
 844                                 * CLUSTER_SIZE(*ef->sb), true);
 845 }
 846
 847 static int find_slot(struct exfat* ef, struct exfat_node* dir,
 848                 cluster_t* cluster, off_t* offset, int subentries)
 849 {
 850         struct iterator it;
 851         int rc;
 852         const struct exfat_entry* entry;
 853         int contiguous = 0;
 854
 855         rc = opendir(ef, dir, &it);
 856         if (rc != 0)
 857                 return rc;
 858         for (;;)
 859         {
 860                 if (contiguous == 0)
 861                 {
 862                         *cluster = it.cluster;
 863                         *offset = it.offset;
 864                 }
 865                 entry = get_entry_ptr(ef, &it);
 866                 if (entry->type & EXFAT_ENTRY_VALID)
 867                         contiguous = 0;
 868                 else
 869                         contiguous++;
 870                 if (contiguous == subentries)
 871                         break;  /* suitable slot is found */
 872                 if (it.offset + sizeof(struct exfat_entry) >= dir->size)
 873                 {
 874                         rc = grow_directory(ef, dir, dir->size,
 875                                         (subentries - contiguous) * sizeof(struct exfat_entry));
 876                         if (rc != 0)
 877                         {
 878                                 closedir(&it);
 879                                 return rc;
 880                         }
 881                 }
 882                 if (!fetch_next_entry(ef, dir, &it))
 883                 {
 884                         closedir(&it);
 885                         return -EIO;
 886                 }
 887         }
 888         closedir(&it);
 889         return 0;
 890 }
 891
 892 static int write_entry(struct exfat* ef, struct exfat_node* dir,
 893                 const le16_t* name, cluster_t cluster, off_t offset, uint16_t attrib)
 894 {
 895         struct exfat_node* node;
 896         struct exfat_entry_meta1 meta1;
 897         struct exfat_entry_meta2 meta2;
 898         const size_t name_length = utf16_length(name);
 899         const int name_entries = DIV_ROUND_UP(name_length, EXFAT_ENAME_MAX);
 900         int i;
 901
 902         node = allocate_node();
 903         if (node == NULL)
 904                 return -ENOMEM;
 905         node->entry_cluster = cluster;
 906         node->entry_offset = offset;
 907         memcpy(node->name, name, name_length * sizeof(le16_t));
 908
 909         memset(&meta1, 0, sizeof(meta1));
 910         meta1.type = EXFAT_ENTRY_FILE;
 911         meta1.continuations = 1 + name_entries;
 912         meta1.attrib = cpu_to_le16(attrib);
 913         exfat_unix2exfat(time(NULL), &meta1.crdate, &meta1.crtime,
 914                         &meta1.crtime_cs);
 915         meta1.adate = meta1.mdate = meta1.crdate;
 916         meta1.atime = meta1.mtime = meta1.crtime;
 917         meta1.mtime_cs = meta1.crtime_cs; /* there is no atime_cs */
 918
 919         memset(&meta2, 0, sizeof(meta2));
 920         meta2.type = EXFAT_ENTRY_FILE_INFO;
 921         meta2.flags = EXFAT_FLAG_ALWAYS1;
 922         meta2.name_length = name_length;
 923         meta2.name_hash = exfat_calc_name_hash(ef, node->name);
 924         meta2.start_cluster = cpu_to_le32(EXFAT_CLUSTER_FREE);
 925
 926         meta1.checksum = exfat_calc_checksum(&meta1, &meta2, node->name);
 927
 928         if (exfat_pwrite(ef->dev, &meta1, sizeof(meta1),
 929                         co2o(ef, cluster, offset)) < 0)
 930         {
 931                 exfat_error("failed to write meta1 entry");
 932                 return -EIO;
 933         }
 934         if (!next_entry(ef, dir, &cluster, &offset))
 935                 return -EIO;
 936         if (exfat_pwrite(ef->dev, &meta2, sizeof(meta2),
 937                         co2o(ef, cluster, offset)) < 0)
 938         {
 939                 exfat_error("failed to write meta2 entry");
 940                 return -EIO;
 941         }
 942         for (i = 0; i < name_entries; i++)
 943         {
 944                 struct exfat_entry_name name_entry = {EXFAT_ENTRY_FILE_NAME, 0};
 945                 memcpy(name_entry.name, node->name + i * EXFAT_ENAME_MAX,
 946                                 MIN(EXFAT_ENAME_MAX, EXFAT_NAME_MAX - i * EXFAT_ENAME_MAX) *
 947                                 sizeof(le16_t));
 948                 if (!next_entry(ef, dir, &cluster, &offset))
 949                         return -EIO;
 950                 if (exfat_pwrite(ef->dev, &name_entry, sizeof(name_entry),
 951                                 co2o(ef, cluster, offset)) < 0)
 952                 {
 953                         exfat_error("failed to write name entry");
 954                         return -EIO;
 955                 }
 956         }
 957
 958         init_node_meta1(node, &meta1);
 959         init_node_meta2(node, &meta2);
 960
 961         tree_attach(dir, node);
 962         exfat_update_mtime(dir);
 963         return 0;
 964 }
 965
 966 static int create(struct exfat* ef, const char* path, uint16_t attrib)
 967 {
 968         struct exfat_node* dir;
 969         struct exfat_node* existing;
 970         cluster_t cluster = EXFAT_CLUSTER_BAD;
 971         off_t offset = -1;
 972         le16_t name[EXFAT_NAME_MAX + 1];
 973         int rc;
 974
 975         rc = exfat_split(ef, &dir, &existing, name, path);
 976         if (rc != 0)
 977                 return rc;
 978         if (existing != NULL)
 979         {
 980                 exfat_put_node(ef, existing);
 981                 exfat_put_node(ef, dir);
 982                 return -EEXIST;
 983         }
 984
 985         rc = find_slot(ef, dir, &cluster, &offset,
 986                         2 + DIV_ROUND_UP(utf16_length(name), EXFAT_ENAME_MAX));
 987         if (rc != 0)
 988         {
 989                 exfat_put_node(ef, dir);
 990                 return rc;
 991         }
 992         rc = write_entry(ef, dir, name, cluster, offset, attrib);
 993         if (rc != 0)
 994         {
 995                 exfat_put_node(ef, dir);
 996                 return rc;
 997         }
 998         rc = exfat_flush_node(ef, dir);
 999         exfat_put_node(ef, dir);
1000         return rc;
1001 }
1002
1003 int exfat_mknod(struct exfat* ef, const char* path)
1004 {
1005         return create(ef, path, EXFAT_ATTRIB_ARCH);
1006 }
1007
1008 int exfat_mkdir(struct exfat* ef, const char* path)
1009 {
1010         int rc;
1011         struct exfat_node* node;
1012
1013         rc = create(ef, path, EXFAT_ATTRIB_DIR);
1014         if (rc != 0)
1015                 return rc;
1016         rc = exfat_lookup(ef, &node, path);
1017         if (rc != 0)
1018                 return 0;
1019         /* directories always have at least one cluster */
1020         rc = exfat_truncate(ef, node, CLUSTER_SIZE(*ef->sb), true);
1021         if (rc != 0)
1022         {
1023                 delete(ef, node);
1024                 exfat_put_node(ef, node);
1025                 return rc;
1026         }
1027         rc = exfat_flush_node(ef, node);
1028         if (rc != 0)
1029         {
1030                 delete(ef, node);
1031                 exfat_put_node(ef, node);
1032                 return rc;
1033         }
1034         exfat_put_node(ef, node);
1035         return 0;
1036 }
1037
1038 static int rename_entry(struct exfat* ef, struct exfat_node* dir,
1039                 struct exfat_node* node, const le16_t* name, cluster_t new_cluster,
1040                 off_t new_offset)
1041 {
1042         struct exfat_entry_meta1 meta1;
1043         struct exfat_entry_meta2 meta2;
1044         cluster_t old_cluster = node->entry_cluster;
1045         off_t old_offset = node->entry_offset;
1046         const size_t name_length = utf16_length(name);
1047         const int name_entries = DIV_ROUND_UP(name_length, EXFAT_ENAME_MAX);
1048         int i;
1049
1050         if (exfat_pread(ef->dev, &meta1, sizeof(meta1),
1051                         co2o(ef, old_cluster, old_offset)) < 0)
1052         {
1053                 exfat_error("failed to read meta1 entry on rename");
1054                 return -EIO;
1055         }
1056         if (!next_entry(ef, node->parent, &old_cluster, &old_offset))
1057                 return -EIO;
1058         if (exfat_pread(ef->dev, &meta2, sizeof(meta2),
1059                         co2o(ef, old_cluster, old_offset)) < 0)
1060         {
1061                 exfat_error("failed to read meta2 entry on rename");
1062                 return -EIO;
1063         }
1064         meta1.continuations = 1 + name_entries;
1065         meta2.name_hash = exfat_calc_name_hash(ef, name);
1066         meta2.name_length = name_length;
1067         meta1.checksum = exfat_calc_checksum(&meta1, &meta2, name);
1068
1069         if (!erase_entry(ef, node))
1070                 return -EIO;
1071
1072         node->entry_cluster = new_cluster;
1073         node->entry_offset = new_offset;
1074
1075         if (exfat_pwrite(ef->dev, &meta1, sizeof(meta1),
1076                         co2o(ef, new_cluster, new_offset)) < 0)
1077         {
1078                 exfat_error("failed to write meta1 entry on rename");
1079                 return -EIO;
1080         }
1081         if (!next_entry(ef, dir, &new_cluster, &new_offset))
1082                 return -EIO;
1083         if (exfat_pwrite(ef->dev, &meta2, sizeof(meta2),
1084                         co2o(ef, new_cluster, new_offset)) < 0)
1085         {
1086                 exfat_error("failed to write meta2 entry on rename");
1087                 return -EIO;
1088         }
1089
1090         for (i = 0; i < name_entries; i++)
1091         {
1092                 struct exfat_entry_name name_entry = {EXFAT_ENTRY_FILE_NAME, 0};
1093                 memcpy(name_entry.name, name + i * EXFAT_ENAME_MAX,
1094                                 EXFAT_ENAME_MAX * sizeof(le16_t));
1095                 if (!next_entry(ef, dir, &new_cluster, &new_offset))
1096                         return -EIO;
1097                 if (exfat_pwrite(ef->dev, &name_entry, sizeof(name_entry),
1098                                 co2o(ef, new_cluster, new_offset)) < 0)
1099                 {
1100                         exfat_error("failed to write name entry on rename");
1101                         return -EIO;
1102                 }
1103         }
1104
1105         memcpy(node->name, name, (EXFAT_NAME_MAX + 1) * sizeof(le16_t));
1106         tree_detach(node);
1107         tree_attach(dir, node);
1108         return 0;
1109 }
1110
1111 int exfat_rename(struct exfat* ef, const char* old_path, const char* new_path)
1112 {
1113         struct exfat_node* node;
1114         struct exfat_node* existing;
1115         struct exfat_node* dir;
1116         cluster_t cluster = EXFAT_CLUSTER_BAD;
1117         off_t offset = -1;
1118         le16_t name[EXFAT_NAME_MAX + 1];
1119         int rc;
1120
1121         rc = exfat_lookup(ef, &node, old_path);
1122         if (rc != 0)
1123                 return rc;
1124
1125         rc = exfat_split(ef, &dir, &existing, name, new_path);
1126         if (rc != 0)
1127         {
1128                 exfat_put_node(ef, node);
1129                 return rc;
1130         }
1131
1132         /* check that target is not a subdirectory of the source */
1133         if (node->flags & EXFAT_ATTRIB_DIR)
1134         {
1135                 struct exfat_node* p;
1136
1137                 for (p = dir; p; p = p->parent)
1138                         if (node == p)
1139                         {
1140                                 if (existing != NULL)
1141                                         exfat_put_node(ef, existing);
1142                                 exfat_put_node(ef, dir);
1143                                 exfat_put_node(ef, node);
1144                                 return -EINVAL;
1145                         }
1146         }
1147
1148         if (existing != NULL)
1149         {
1150                 /* remove target if it's not the same node as source */
1151                 if (existing != node)
1152                 {
1153                         if (existing->flags & EXFAT_ATTRIB_DIR)
1154                         {
1155                                 if (node->flags & EXFAT_ATTRIB_DIR)
1156                                         rc = exfat_rmdir(ef, existing);
1157                                 else
1158                                         rc = -ENOTDIR;
1159                         }
1160                         else
1161                         {
1162                                 if (!(node->flags & EXFAT_ATTRIB_DIR))
1163                                         rc = exfat_unlink(ef, existing);
1164                                 else
1165                                         rc = -EISDIR;
1166                         }
1167                         exfat_put_node(ef, existing);
1168                         if (rc != 0)
1169                         {
1170                                 /* free clusters even if something went wrong; overwise they
1171                                    will be just lost */
1172                                 exfat_cleanup_node(ef, existing);
1173                                 exfat_put_node(ef, dir);
1174                                 exfat_put_node(ef, node);
1175                                 return rc;
1176                         }
1177                         rc = exfat_cleanup_node(ef, existing);
1178                         if (rc != 0)
1179                         {
1180                                 exfat_put_node(ef, dir);
1181                                 exfat_put_node(ef, node);
1182                                 return rc;
1183                         }
1184                 }
1185                 else
1186                         exfat_put_node(ef, existing);
1187         }
1188
1189         rc = find_slot(ef, dir, &cluster, &offset,
1190                         2 + DIV_ROUND_UP(utf16_length(name), EXFAT_ENAME_MAX));
1191         if (rc != 0)
1192         {
1193                 exfat_put_node(ef, dir);
1194                 exfat_put_node(ef, node);
1195                 return rc;
1196         }
1197         rc = rename_entry(ef, dir, node, name, cluster, offset);
1198         exfat_put_node(ef, dir);
1199         exfat_put_node(ef, node);
1200         return rc;
1201 }
1202
1203 void exfat_utimes(struct exfat_node* node, const struct timespec tv[2])
1204 {
1205         node->atime = tv[0].tv_sec;
1206         node->mtime = tv[1].tv_sec;
1207         node->flags |= EXFAT_ATTRIB_DIRTY;
1208 }
1209
1210 void exfat_update_atime(struct exfat_node* node)
1211 {
1212         node->atime = time(NULL);
1213         node->flags |= EXFAT_ATTRIB_DIRTY;
1214 }
1215
1216 void exfat_update_mtime(struct exfat_node* node)
1217 {
1218         node->mtime = time(NULL);
1219         node->flags |= EXFAT_ATTRIB_DIRTY;
1220 }
1221
1222 const char* exfat_get_label(struct exfat* ef)
1223 {
1224         return ef->label;
1225 }
1226
1227 static int find_label(struct exfat* ef, cluster_t* cluster, off_t* offset)
1228 {
1229         struct iterator it;
1230         int rc;
1231
1232         rc = opendir(ef, ef->root, &it);
1233         if (rc != 0)
1234                 return rc;
1235
1236         for (;;)
1237         {
1238                 if (it.offset >= ef->root->size)
1239                 {
1240                         closedir(&it);
1241                         return -ENOENT;
1242                 }
1243
1244                 if (get_entry_ptr(ef, &it)->type == EXFAT_ENTRY_LABEL)
1245                 {
1246                         *cluster = it.cluster;
1247                         *offset = it.offset;
1248                         closedir(&it);
1249                         return 0;
1250                 }
1251
1252                 if (!fetch_next_entry(ef, ef->root, &it))
1253                 {
1254                         closedir(&it);
1255                         return -EIO;
1256                 }
1257         }
1258 }
1259
1260 int exfat_set_label(struct exfat* ef, const char* label)
1261 {
1262         le16_t label_utf16[EXFAT_ENAME_MAX + 1];
1263         int rc;
1264         cluster_t cluster;
1265         off_t offset;
1266         struct exfat_entry_label entry;
1267
1268         memset(label_utf16, 0, sizeof(label_utf16));
1269         rc = utf8_to_utf16(label_utf16, label, EXFAT_ENAME_MAX, strlen(label));
1270         if (rc != 0)
1271                 return rc;
1272
1273         rc = find_label(ef, &cluster, &offset);
1274         if (rc == -ENOENT)
1275                 rc = find_slot(ef, ef->root, &cluster, &offset, 1);
1276         if (rc != 0)
1277                 return rc;
1278
1279         entry.type = EXFAT_ENTRY_LABEL;
1280         entry.length = utf16_length(label_utf16);
1281         memcpy(entry.name, label_utf16, sizeof(entry.name));
1282         if (entry.length == 0)
1283                 entry.type ^= EXFAT_ENTRY_VALID;
1284
1285         if (exfat_pwrite(ef->dev, &entry, sizeof(struct exfat_entry_label),
1286                         co2o(ef, cluster, offset)) < 0)
1287         {
1288                 exfat_error("failed to write label entry");
1289                 return -EIO;
1290         }
1291         strcpy(ef->label, label);
1292         return 0;
1293 }