src/ext4_xattr.c

   1 /*
   2  * Copyright (c) 2015 Grzegorz Kostka (kostka.grzegorz@gmail.com)
   3  * Copyright (c) 2015 Kaho Ng (ngkaho1234@gmail.com)
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  *
   9  * - Redistributions of source code must retain the above copyright
  10  *   notice, this list of conditions and the following disclaimer.
  11  * - Redistributions in binary form must reproduce the above copyright
  12  *   notice, this list of conditions and the following disclaimer in the
  13  *   documentation and/or other materials provided with the distribution.
  14  * - The name of the author may not be used to endorse or promote products
  15  *   derived from this software without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  */
  28
  29 /** @addtogroup lwext4
  30  * @{
  31  */
  32 /**
  33  * @file  ext4_xattr.c
  34  * @brief Extended Attribute manipulation.
  35  */
  36
  37 #include "ext4_config.h"
  38 #include "ext4_types.h"
  39 #include "ext4_misc.h"
  40 #include "ext4_errno.h"
  41 #include "ext4_debug.h"
  42
  43 #include "ext4_fs.h"
  44 #include "ext4_trans.h"
  45 #include "ext4_xattr.h"
  46 #include "ext4_blockdev.h"
  47 #include "ext4_super.h"
  48 #include "ext4_crc32.h"
  49 #include "ext4_block_group.h"
  50 #include "ext4_balloc.h"
  51 #include "ext4_inode.h"
  52
  53 #include <string.h>
  54 #include <stdlib.h>
  55
  56 /**
  57  * @file  ext4_xattr.c
  58  * @brief Extended Attribute Manipulation
  59  */
  60
  61 #define NAME_HASH_SHIFT 5
  62 #define VALUE_HASH_SHIFT 16
  63
  64 static inline void ext4_xattr_compute_hash(struct ext4_xattr_header *header,
  65                                            struct ext4_xattr_entry *entry)
  66 {
  67         uint32_t hash = 0;
  68         char *name = EXT4_XATTR_NAME(entry);
  69         int n;
  70
  71         for (n = 0; n < entry->e_name_len; n++) {
  72                 hash = (hash << NAME_HASH_SHIFT) ^
  73                        (hash >> (8 * sizeof(hash) - NAME_HASH_SHIFT)) ^ *name++;
  74         }
  75
  76         if (entry->e_value_block == 0 && entry->e_value_size != 0) {
  77                 uint32_t *value =
  78                     (uint32_t *)((char *)header + to_le16(entry->e_value_offs));
  79                 for (n = (to_le32(entry->e_value_size) + EXT4_XATTR_ROUND) >>
  80                          EXT4_XATTR_PAD_BITS;
  81                      n; n--) {
  82                         hash = (hash << VALUE_HASH_SHIFT) ^
  83                                (hash >> (8 * sizeof(hash) - VALUE_HASH_SHIFT)) ^
  84                                to_le32(*value++);
  85                 }
  86         }
  87         entry->e_hash = to_le32(hash);
  88 }
  89
  90 #define BLOCK_HASH_SHIFT 16
  91
  92 /*
  93  * ext4_xattr_rehash()
  94  *
  95  * Re-compute the extended attribute hash value after an entry has changed.
  96  */
  97 static void ext4_xattr_rehash(struct ext4_xattr_header *header,
  98                               struct ext4_xattr_entry *entry)
  99 {
 100         struct ext4_xattr_entry *here;
 101         uint32_t hash = 0;
 102
 103         ext4_xattr_compute_hash(header, entry);
 104         here = EXT4_XATTR_ENTRY(header + 1);
 105         while (!EXT4_XATTR_IS_LAST_ENTRY(here)) {
 106                 if (!here->e_hash) {
 107                         /* Block is not shared if an entry's hash value == 0 */
 108                         hash = 0;
 109                         break;
 110                 }
 111                 hash = (hash << BLOCK_HASH_SHIFT) ^
 112                        (hash >> (8 * sizeof(hash) - BLOCK_HASH_SHIFT)) ^
 113                        to_le32(here->e_hash);
 114                 here = EXT4_XATTR_NEXT(here);
 115         }
 116         header->h_hash = to_le32(hash);
 117 }
 118
 119 #if CONFIG_META_CSUM_ENABLE
 120 static uint32_t
 121 ext4_xattr_block_checksum(struct ext4_inode_ref *inode_ref,
 122                           ext4_fsblk_t blocknr,
 123                           struct ext4_xattr_header *header)
 124 {
 125         uint32_t checksum = 0;
 126         uint64_t le64_blocknr = blocknr;
 127         struct ext4_sblock *sb = &inode_ref->fs->sb;
 128
 129         if (ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM)) {
 130                 uint32_t orig_checksum;
 131
 132                 /* Preparation: temporarily set bg checksum to 0 */
 133                 orig_checksum = header->h_checksum;
 134                 header->h_checksum = 0;
 135                 /* First calculate crc32 checksum against fs uuid */
 136                 checksum = ext4_crc32c(EXT4_CRC32_INIT, sb->uuid,
 137                                 sizeof(sb->uuid));
 138                 /* Then calculate crc32 checksum block number */
 139                 checksum = ext4_crc32c(checksum, &le64_blocknr,
 140                                      sizeof(le64_blocknr));
 141                 /* Finally calculate crc32 checksum against
 142                  * the entire xattr block */
 143                 checksum = ext4_crc32c(checksum, header,
 144                                    ext4_sb_get_block_size(sb));
 145                 header->h_checksum = orig_checksum;
 146         }
 147         return checksum;
 148 }
 149 #else
 150 #define ext4_xattr_block_checksum(...) 0
 151 #endif
 152
 153 static void
 154 ext4_xattr_set_block_checksum(struct ext4_inode_ref *inode_ref,
 155                               ext4_fsblk_t blocknr __unused,
 156                               struct ext4_xattr_header *header)
 157 {
 158         struct ext4_sblock *sb = &inode_ref->fs->sb;
 159         if (!ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM))
 160                 return;
 161
 162         header->h_checksum =
 163                 ext4_xattr_block_checksum(inode_ref, blocknr, header);
 164 }
 165
 166 static int ext4_xattr_item_cmp(struct ext4_xattr_item *a,
 167                                struct ext4_xattr_item *b)
 168 {
 169         int result;
 170         if (a->is_data && !b->is_data)
 171                 return -1;
 172
 173         if (!a->is_data && b->is_data)
 174                 return 1;
 175
 176         result = a->name_index - b->name_index;
 177         if (result)
 178                 return result;
 179
 180         result = a->name_len - b->name_len;
 181         if (result)
 182                 return result;
 183
 184         return memcmp(a->name, b->name, a->name_len);
 185 }
 186
 187 RB_GENERATE_INTERNAL(ext4_xattr_tree, ext4_xattr_item, node,
 188                      ext4_xattr_item_cmp, static inline)
 189
 190 static struct ext4_xattr_item *
 191 ext4_xattr_item_alloc(uint8_t name_index, const char *name, size_t name_len)
 192 {
 193         struct ext4_xattr_item *item;
 194         item = malloc(sizeof(struct ext4_xattr_item) + name_len);
 195         if (!item)
 196                 return NULL;
 197
 198         item->name_index = name_index;
 199         item->name = (char *)(item + 1);
 200         item->name_len = name_len;
 201         item->data = NULL;
 202         item->data_size = 0;
 203         item->in_inode = false;
 204
 205         memset(&item->node, 0, sizeof(item->node));
 206         memcpy(item->name, name, name_len);
 207
 208         if (name_index == EXT4_XATTR_INDEX_SYSTEM &&
 209             name_len == 4 &&
 210             !memcmp(name, "data", 4))
 211                 item->is_data = true;
 212         else
 213                 item->is_data = false;
 214
 215         return item;
 216 }
 217
 218 static int ext4_xattr_item_alloc_data(struct ext4_xattr_item *item,
 219                                       const void *orig_data, size_t data_size)
 220 {
 221         void *data = NULL;
 222         ext4_assert(!item->data);
 223         data = malloc(data_size);
 224         if (!data)
 225                 return ENOMEM;
 226
 227         if (orig_data)
 228                 memcpy(data, orig_data, data_size);
 229
 230         item->data = data;
 231         item->data_size = data_size;
 232         return EOK;
 233 }
 234
 235 static void ext4_xattr_item_free_data(struct ext4_xattr_item *item)
 236 {
 237         ext4_assert(item->data);
 238         free(item->data);
 239         item->data = NULL;
 240         item->data_size = 0;
 241 }
 242
 243 static int ext4_xattr_item_resize_data(struct ext4_xattr_item *item,
 244                                        size_t new_data_size)
 245 {
 246         if (new_data_size != item->data_size) {
 247                 void *new_data;
 248                 new_data = realloc(item->data, new_data_size);
 249                 if (!new_data)
 250                         return ENOMEM;
 251
 252                 item->data = new_data;
 253                 item->data_size = new_data_size;
 254         }
 255         return EOK;
 256 }
 257
 258 static void ext4_xattr_item_free(struct ext4_xattr_item *item)
 259 {
 260         if (item->data)
 261                 ext4_xattr_item_free_data(item);
 262
 263         free(item);
 264 }
 265
 266 static void *ext4_xattr_entry_data(struct ext4_xattr_ref *xattr_ref,
 267                                    struct ext4_xattr_entry *entry,
 268                                    bool in_inode)
 269 {
 270         char *ret;
 271         if (in_inode) {
 272                 struct ext4_xattr_ibody_header *header;
 273                 struct ext4_xattr_entry *first_entry;
 274                 int16_t inode_size =
 275                     ext4_get16(&xattr_ref->fs->sb, inode_size);
 276                 header = EXT4_XATTR_IHDR(&xattr_ref->fs->sb,
 277                                 xattr_ref->inode_ref->inode);
 278                 first_entry = EXT4_XATTR_IFIRST(header);
 279
 280                 ret = ((char *)first_entry + to_le16(entry->e_value_offs));
 281                 if (ret + EXT4_XATTR_SIZE(to_le32(entry->e_value_size)) -
 282                         (char *)xattr_ref->inode_ref->inode > inode_size)
 283                         ret = NULL;
 284
 285                 return ret;
 286
 287         }
 288         int32_t block_size = ext4_sb_get_block_size(&xattr_ref->fs->sb);
 289         ret = ((char *)xattr_ref->block.data + to_le16(entry->e_value_offs));
 290         if (ret + EXT4_XATTR_SIZE(to_le32(entry->e_value_size)) -
 291                         (char *)xattr_ref->block.data > block_size)
 292                 ret = NULL;
 293         return ret;
 294 }
 295
 296 static int ext4_xattr_block_fetch(struct ext4_xattr_ref *xattr_ref)
 297 {
 298         int ret = EOK;
 299         size_t size_rem;
 300         void *data;
 301         struct ext4_xattr_entry *entry = NULL;
 302
 303         ext4_assert(xattr_ref->block.data);
 304         entry = EXT4_XATTR_BFIRST(&xattr_ref->block);
 305
 306         size_rem = ext4_sb_get_block_size(&xattr_ref->fs->sb);
 307         for (; size_rem > 0 && !EXT4_XATTR_IS_LAST_ENTRY(entry);
 308              entry = EXT4_XATTR_NEXT(entry),
 309              size_rem -= EXT4_XATTR_LEN(entry->e_name_len)) {
 310                 struct ext4_xattr_item *item;
 311                 char *e_name = EXT4_XATTR_NAME(entry);
 312
 313                 data = ext4_xattr_entry_data(xattr_ref, entry, false);
 314                 if (!data) {
 315                         ret = EIO;
 316                         goto Finish;
 317                 }
 318
 319                 item = ext4_xattr_item_alloc(entry->e_name_index, e_name,
 320                                              (size_t)entry->e_name_len);
 321                 if (!item) {
 322                         ret = ENOMEM;
 323                         goto Finish;
 324                 }
 325                 if (ext4_xattr_item_alloc_data(
 326                         item, data, to_le32(entry->e_value_size)) != EOK) {
 327                         ext4_xattr_item_free(item);
 328                         ret = ENOMEM;
 329                         goto Finish;
 330                 }
 331                 RB_INSERT(ext4_xattr_tree, &xattr_ref->root, item);
 332                 xattr_ref->block_size_rem -=
 333                         EXT4_XATTR_SIZE(item->data_size) +
 334                         EXT4_XATTR_LEN(item->name_len);
 335                 xattr_ref->ea_size += EXT4_XATTR_SIZE(item->data_size) +
 336                                       EXT4_XATTR_LEN(item->name_len);
 337         }
 338
 339 Finish:
 340         return ret;
 341 }
 342
 343 static int ext4_xattr_inode_fetch(struct ext4_xattr_ref *xattr_ref)
 344 {
 345         void *data;
 346         size_t size_rem;
 347         int ret = EOK;
 348         struct ext4_xattr_ibody_header *header = NULL;
 349         struct ext4_xattr_entry *entry = NULL;
 350         uint16_t inode_size = ext4_get16(&xattr_ref->fs->sb, inode_size);
 351         uint16_t extra_isize = ext4_inode_get_extra_isize(&xattr_ref->fs->sb,
 352                                         xattr_ref->inode_ref->inode);
 353
 354         header = EXT4_XATTR_IHDR(&xattr_ref->fs->sb,
 355                                  xattr_ref->inode_ref->inode);
 356         entry = EXT4_XATTR_IFIRST(header);
 357
 358         size_rem = inode_size - EXT4_GOOD_OLD_INODE_SIZE -
 359                    extra_isize;
 360         for (; size_rem > 0 && !EXT4_XATTR_IS_LAST_ENTRY(entry);
 361              entry = EXT4_XATTR_NEXT(entry),
 362              size_rem -= EXT4_XATTR_LEN(entry->e_name_len)) {
 363                 struct ext4_xattr_item *item;
 364                 char *e_name = EXT4_XATTR_NAME(entry);
 365
 366                 data = ext4_xattr_entry_data(xattr_ref, entry, true);
 367                 if (!data) {
 368                         ret = EIO;
 369                         goto Finish;
 370                 }
 371
 372                 item = ext4_xattr_item_alloc(entry->e_name_index, e_name,
 373                                              (size_t)entry->e_name_len);
 374                 if (!item) {
 375                         ret = ENOMEM;
 376                         goto Finish;
 377                 }
 378                 if (ext4_xattr_item_alloc_data(
 379                         item, data, to_le32(entry->e_value_size)) != EOK) {
 380                         ext4_xattr_item_free(item);
 381                         ret = ENOMEM;
 382                         goto Finish;
 383                 }
 384                 item->in_inode = true;
 385                 RB_INSERT(ext4_xattr_tree, &xattr_ref->root, item);
 386                 xattr_ref->inode_size_rem -=
 387                         EXT4_XATTR_SIZE(item->data_size) +
 388                         EXT4_XATTR_LEN(item->name_len);
 389                 xattr_ref->ea_size += EXT4_XATTR_SIZE(item->data_size) +
 390                                       EXT4_XATTR_LEN(item->name_len);
 391         }
 392
 393 Finish:
 394         return ret;
 395 }
 396
 397 static size_t ext4_xattr_inode_space(struct ext4_xattr_ref *xattr_ref)
 398 {
 399         uint16_t inode_size = ext4_get16(&xattr_ref->fs->sb, inode_size);
 400         uint16_t extra_isize = ext4_inode_get_extra_isize(&xattr_ref->fs->sb,
 401                                         xattr_ref->inode_ref->inode);
 402         uint16_t size_rem = inode_size - EXT4_GOOD_OLD_INODE_SIZE -
 403                             extra_isize;
 404         return size_rem;
 405 }
 406
 407 static size_t ext4_xattr_block_space(struct ext4_xattr_ref *xattr_ref)
 408 {
 409         return ext4_sb_get_block_size(&xattr_ref->fs->sb);
 410 }
 411
 412 static int ext4_xattr_fetch(struct ext4_xattr_ref *xattr_ref)
 413 {
 414         int ret = EOK;
 415         uint16_t inode_size = ext4_get16(&xattr_ref->fs->sb, inode_size);
 416         if (inode_size > EXT4_GOOD_OLD_INODE_SIZE) {
 417                 ret = ext4_xattr_inode_fetch(xattr_ref);
 418                 if (ret != EOK)
 419                         return ret;
 420         }
 421
 422         if (xattr_ref->block_loaded)
 423                 ret = ext4_xattr_block_fetch(xattr_ref);
 424
 425         xattr_ref->dirty = false;
 426         return ret;
 427 }
 428
 429 static struct ext4_xattr_item *
 430 ext4_xattr_lookup_item(struct ext4_xattr_ref *xattr_ref, uint8_t name_index,
 431                        const char *name, size_t name_len)
 432 {
 433         struct ext4_xattr_item tmp = {
 434                 .name_index = name_index,
 435                 .name = (char *)name, /*RB_FIND - won't touch this string*/
 436                 .name_len = name_len,
 437         };
 438         if (name_index == EXT4_XATTR_INDEX_SYSTEM &&
 439             name_len == 4 &&
 440             !memcmp(name, "data", 4))
 441                 tmp.is_data = true;
 442
 443         return RB_FIND(ext4_xattr_tree, &xattr_ref->root, &tmp);
 444 }
 445
 446 static struct ext4_xattr_item *
 447 ext4_xattr_insert_item(struct ext4_xattr_ref *xattr_ref, uint8_t name_index,
 448                        const char *name, size_t name_len, const void *data,
 449                        size_t data_size,
 450                        int *err)
 451 {
 452         struct ext4_xattr_item *item;
 453         item = ext4_xattr_item_alloc(name_index, name, name_len);
 454         if (!item) {
 455                 if (err)
 456                         *err = ENOMEM;
 457
 458                 return NULL;
 459         }
 460
 461         if ((xattr_ref->ea_size + EXT4_XATTR_SIZE(data_size) +
 462                 EXT4_XATTR_LEN(item->name_len)
 463                         >
 464             ext4_xattr_inode_space(xattr_ref) -
 465                 sizeof(struct ext4_xattr_ibody_header))
 466                 &&
 467             (xattr_ref->ea_size + EXT4_XATTR_SIZE(data_size) +
 468                 EXT4_XATTR_LEN(item->name_len) >
 469             ext4_xattr_block_space(xattr_ref) -
 470                 sizeof(struct ext4_xattr_header))) {
 471                 ext4_xattr_item_free(item);
 472
 473                 if (err)
 474                         *err = ENOSPC;
 475
 476                 return NULL;
 477         }
 478         item->in_inode = true;
 479         if (xattr_ref->inode_size_rem <
 480             EXT4_XATTR_SIZE(data_size) +
 481             EXT4_XATTR_LEN(item->name_len)) {
 482                 if (xattr_ref->block_size_rem <
 483                     EXT4_XATTR_SIZE(data_size) +
 484                     EXT4_XATTR_LEN(item->name_len)) {
 485                         if (err)
 486                                 *err = ENOSPC;
 487
 488                         return NULL;
 489                 }
 490
 491                 item->in_inode = false;
 492         }
 493         if (ext4_xattr_item_alloc_data(item, data, data_size) != EOK) {
 494                 ext4_xattr_item_free(item);
 495                 if (err)
 496                         *err = ENOMEM;
 497
 498                 return NULL;
 499         }
 500         RB_INSERT(ext4_xattr_tree, &xattr_ref->root, item);
 501         xattr_ref->ea_size +=
 502             EXT4_XATTR_SIZE(item->data_size) + EXT4_XATTR_LEN(item->name_len);
 503         if (item->in_inode) {
 504                 xattr_ref->inode_size_rem -=
 505                         EXT4_XATTR_SIZE(item->data_size) +
 506                         EXT4_XATTR_LEN(item->name_len);
 507         } else {
 508                 xattr_ref->block_size_rem -=
 509                         EXT4_XATTR_SIZE(item->data_size) +
 510                         EXT4_XATTR_LEN(item->name_len);
 511         }
 512         xattr_ref->dirty = true;
 513         if (err)
 514                 *err = EOK;
 515
 516         return item;
 517 }
 518
 519 static int ext4_xattr_remove_item(struct ext4_xattr_ref *xattr_ref,
 520                                   uint8_t name_index, const char *name,
 521                                   size_t name_len)
 522 {
 523         int ret = ENOENT;
 524         struct ext4_xattr_item *item =
 525             ext4_xattr_lookup_item(xattr_ref, name_index, name, name_len);
 526         if (item) {
 527                 if (item == xattr_ref->iter_from)
 528                         xattr_ref->iter_from =
 529                             RB_NEXT(ext4_xattr_tree, &xattr_ref->root, item);
 530
 531                 xattr_ref->ea_size -= EXT4_XATTR_SIZE(item->data_size) +
 532                                       EXT4_XATTR_LEN(item->name_len);
 533
 534                 if (item->in_inode) {
 535                         xattr_ref->inode_size_rem +=
 536                                 EXT4_XATTR_SIZE(item->data_size) +
 537                                 EXT4_XATTR_LEN(item->name_len);
 538                 } else {
 539                         xattr_ref->block_size_rem +=
 540                                 EXT4_XATTR_SIZE(item->data_size) +
 541                                 EXT4_XATTR_LEN(item->name_len);
 542                 }
 543
 544                 RB_REMOVE(ext4_xattr_tree, &xattr_ref->root, item);
 545                 ext4_xattr_item_free(item);
 546                 xattr_ref->dirty = true;
 547                 ret = EOK;
 548         }
 549         return ret;
 550 }
 551
 552 static int ext4_xattr_resize_item(struct ext4_xattr_ref *xattr_ref,
 553                                   struct ext4_xattr_item *item,
 554                                   size_t new_data_size)
 555 {
 556         int ret = EOK;
 557         bool to_inode = false, to_block = false;
 558         size_t old_data_size = item->data_size;
 559         int32_t orig_room_size = item->in_inode ?
 560                 xattr_ref->inode_size_rem :
 561                 xattr_ref->block_size_rem;
 562
 563         /*
 564          * Check if we can hold this entry in both in-inode and
 565          * on-block form
 566          */
 567         if ((xattr_ref->ea_size - EXT4_XATTR_SIZE(old_data_size) +
 568                 EXT4_XATTR_SIZE(new_data_size)
 569                         >
 570             ext4_xattr_inode_space(xattr_ref) -
 571                 sizeof(struct ext4_xattr_ibody_header))
 572                 &&
 573             (xattr_ref->ea_size - EXT4_XATTR_SIZE(old_data_size) +
 574                 EXT4_XATTR_SIZE(new_data_size)
 575                         >
 576             ext4_xattr_block_space(xattr_ref) -
 577                 sizeof(struct ext4_xattr_header))) {
 578
 579                 return ENOSPC;
 580         }
 581
 582         /*
 583          * More complicated case: we do not allow entries stucking in
 584          * the middle between in-inode space and on-block space, so
 585          * the entry has to stay in either inode space or block space.
 586          */
 587         if (item->in_inode) {
 588                 if (xattr_ref->inode_size_rem +
 589                                 EXT4_XATTR_SIZE(old_data_size) <
 590                                 EXT4_XATTR_SIZE(new_data_size)) {
 591                         if (xattr_ref->block_size_rem <
 592                                         EXT4_XATTR_SIZE(new_data_size) +
 593                                         EXT4_XATTR_LEN(item->name_len))
 594                                 return ENOSPC;
 595
 596                         to_block = true;
 597                 }
 598         } else {
 599                 if (xattr_ref->block_size_rem +
 600                                 EXT4_XATTR_SIZE(old_data_size) <
 601                                 EXT4_XATTR_SIZE(new_data_size)) {
 602                         if (xattr_ref->inode_size_rem <
 603                                         EXT4_XATTR_SIZE(new_data_size) +
 604                                         EXT4_XATTR_LEN(item->name_len))
 605                                 return ENOSPC;
 606
 607                         to_inode = true;
 608                 }
 609         }
 610         ret = ext4_xattr_item_resize_data(item, new_data_size);
 611         if (ret != EOK)
 612                 return ret;
 613
 614         xattr_ref->ea_size =
 615             xattr_ref->ea_size -
 616             EXT4_XATTR_SIZE(old_data_size) +
 617             EXT4_XATTR_SIZE(new_data_size);
 618
 619         /*
 620          * This entry may originally lie in inode space or block space,
 621          * and it is going to be transferred to another place.
 622          */
 623         if (to_block) {
 624                 xattr_ref->inode_size_rem +=
 625                         EXT4_XATTR_SIZE(old_data_size) +
 626                         EXT4_XATTR_LEN(item->name_len);
 627                 xattr_ref->block_size_rem -=
 628                         EXT4_XATTR_SIZE(new_data_size) +
 629                         EXT4_XATTR_LEN(item->name_len);
 630                 item->in_inode = false;
 631         } else if (to_inode) {
 632                 xattr_ref->block_size_rem +=
 633                         EXT4_XATTR_SIZE(old_data_size) +
 634                         EXT4_XATTR_LEN(item->name_len);
 635                 xattr_ref->inode_size_rem -=
 636                         EXT4_XATTR_SIZE(new_data_size) +
 637                         EXT4_XATTR_LEN(item->name_len);
 638                 item->in_inode = true;
 639         } else {
 640                 /*
 641                  * No need to transfer as there is enough space for the entry
 642                  * to stay in inode space or block space it used to be.
 643                  */
 644                 orig_room_size +=
 645                         EXT4_XATTR_SIZE(old_data_size);
 646                 orig_room_size -=
 647                         EXT4_XATTR_SIZE(new_data_size);
 648                 if (item->in_inode)
 649                         xattr_ref->inode_size_rem = orig_room_size;
 650                 else
 651                         xattr_ref->block_size_rem = orig_room_size;
 652
 653         }
 654         xattr_ref->dirty = true;
 655         return ret;
 656 }
 657
 658 static void ext4_xattr_purge_items(struct ext4_xattr_ref *xattr_ref)
 659 {
 660         struct ext4_xattr_item *item, *save_item;
 661         RB_FOREACH_SAFE(item, ext4_xattr_tree, &xattr_ref->root, save_item) {
 662                 RB_REMOVE(ext4_xattr_tree, &xattr_ref->root, item);
 663                 ext4_xattr_item_free(item);
 664         }
 665         xattr_ref->ea_size = 0;
 666         if (ext4_xattr_inode_space(xattr_ref) <
 667             sizeof(struct ext4_xattr_ibody_header))
 668                 xattr_ref->inode_size_rem = 0;
 669         else
 670                 xattr_ref->inode_size_rem =
 671                         ext4_xattr_inode_space(xattr_ref) -
 672                         sizeof(struct ext4_xattr_ibody_header);
 673
 674         xattr_ref->block_size_rem =
 675                 ext4_xattr_block_space(xattr_ref) -
 676                 sizeof(struct ext4_xattr_header);
 677 }
 678
 679 static int ext4_xattr_try_alloc_block(struct ext4_xattr_ref *xattr_ref)
 680 {
 681         int ret = EOK;
 682
 683         ext4_fsblk_t xattr_block = 0;
 684         xattr_block = ext4_inode_get_file_acl(xattr_ref->inode_ref->inode,
 685                                               &xattr_ref->fs->sb);
 686         if (!xattr_block) {
 687                 ext4_fsblk_t goal =
 688                         ext4_fs_inode_to_goal_block(xattr_ref->inode_ref);
 689
 690                 ret = ext4_balloc_alloc_block(xattr_ref->inode_ref,
 691                                               goal,
 692                                               &xattr_block);
 693                 if (ret != EOK)
 694                         goto Finish;
 695
 696                 ret = ext4_trans_block_get(xattr_ref->fs->bdev, &xattr_ref->block,
 697                                      xattr_block);
 698                 if (ret != EOK) {
 699                         ext4_balloc_free_block(xattr_ref->inode_ref,
 700                                                xattr_block);
 701                         goto Finish;
 702                 }
 703
 704                 ext4_inode_set_file_acl(xattr_ref->inode_ref->inode,
 705                                         &xattr_ref->fs->sb, xattr_block);
 706                 xattr_ref->inode_ref->dirty = true;
 707                 xattr_ref->block_loaded = true;
 708         }
 709
 710 Finish:
 711         return ret;
 712 }
 713
 714 static void ext4_xattr_try_free_block(struct ext4_xattr_ref *xattr_ref)
 715 {
 716         ext4_fsblk_t xattr_block;
 717         xattr_block = ext4_inode_get_file_acl(xattr_ref->inode_ref->inode,
 718                                               &xattr_ref->fs->sb);
 719         ext4_inode_set_file_acl(xattr_ref->inode_ref->inode, &xattr_ref->fs->sb,
 720                                 0);
 721         ext4_block_set(xattr_ref->fs->bdev, &xattr_ref->block);
 722         ext4_balloc_free_block(xattr_ref->inode_ref, xattr_block);
 723         xattr_ref->inode_ref->dirty = true;
 724         xattr_ref->block_loaded = false;
 725 }
 726
 727 static void ext4_xattr_set_block_header(struct ext4_xattr_ref *xattr_ref)
 728 {
 729         struct ext4_xattr_header *block_header = NULL;
 730         block_header = EXT4_XATTR_BHDR(&xattr_ref->block);
 731
 732         memset(block_header, 0, sizeof(struct ext4_xattr_header));
 733         block_header->h_magic = EXT4_XATTR_MAGIC;
 734         block_header->h_refcount = to_le32(1);
 735         block_header->h_blocks = to_le32(1);
 736 }
 737
 738 static void
 739 ext4_xattr_set_inode_entry(struct ext4_xattr_item *item,
 740                            struct ext4_xattr_ibody_header *ibody_header,
 741                            struct ext4_xattr_entry *entry, void *ibody_data_ptr)
 742 {
 743         entry->e_name_len = (uint8_t)item->name_len;
 744         entry->e_name_index = item->name_index;
 745         entry->e_value_offs =
 746             to_le16((char *)ibody_data_ptr - (char *)EXT4_XATTR_IFIRST(ibody_header));
 747         entry->e_value_block = 0;
 748         entry->e_value_size = to_le32(item->data_size);
 749 }
 750
 751 static void ext4_xattr_set_block_entry(struct ext4_xattr_item *item,
 752                                        struct ext4_xattr_header *block_header,
 753                                        struct ext4_xattr_entry *block_entry,
 754                                        void *block_data_ptr)
 755 {
 756         block_entry->e_name_len = (uint8_t)item->name_len;
 757         block_entry->e_name_index = item->name_index;
 758         block_entry->e_value_offs =
 759             to_le16((char *)block_data_ptr - (char *)block_header);
 760         block_entry->e_value_block = 0;
 761         block_entry->e_value_size = to_le32(item->data_size);
 762 }
 763
 764 static int ext4_xattr_write_to_disk(struct ext4_xattr_ref *xattr_ref)
 765 {
 766         int ret = EOK;
 767         bool block_modified = false;
 768         void *ibody_data = NULL;
 769         void *block_data = NULL;
 770         struct ext4_xattr_item *item, *save_item;
 771         size_t inode_size_rem, block_size_rem;
 772         struct ext4_xattr_ibody_header *ibody_header = NULL;
 773         struct ext4_xattr_header *block_header = NULL;
 774         struct ext4_xattr_entry *entry = NULL;
 775         struct ext4_xattr_entry *block_entry = NULL;
 776
 777         inode_size_rem = ext4_xattr_inode_space(xattr_ref);
 778         block_size_rem = ext4_xattr_block_space(xattr_ref);
 779         if (inode_size_rem > sizeof(struct ext4_xattr_ibody_header)) {
 780                 ibody_header = EXT4_XATTR_IHDR(&xattr_ref->fs->sb,
 781                                                xattr_ref->inode_ref->inode);
 782                 entry = EXT4_XATTR_IFIRST(ibody_header);
 783         }
 784
 785         if (!xattr_ref->dirty)
 786                 goto Finish;
 787         /* If there are enough spaces in the ibody EA table.*/
 788         if (inode_size_rem > sizeof(struct ext4_xattr_ibody_header)) {
 789                 memset(ibody_header, 0, inode_size_rem);
 790                 ibody_header->h_magic = EXT4_XATTR_MAGIC;
 791                 ibody_data = (char *)ibody_header + inode_size_rem;
 792                 inode_size_rem -= sizeof(struct ext4_xattr_ibody_header);
 793
 794                 xattr_ref->inode_ref->dirty = true;
 795         }
 796         /* If we need an extra block to hold the EA entries*/
 797         if (xattr_ref->ea_size > inode_size_rem) {
 798                 if (!xattr_ref->block_loaded) {
 799                         ret = ext4_xattr_try_alloc_block(xattr_ref);
 800                         if (ret != EOK)
 801                                 goto Finish;
 802                 }
 803                 memset(xattr_ref->block.data, 0,
 804                        ext4_sb_get_block_size(&xattr_ref->fs->sb));
 805                 block_header = EXT4_XATTR_BHDR(&xattr_ref->block);
 806                 block_entry = EXT4_XATTR_BFIRST(&xattr_ref->block);
 807                 ext4_xattr_set_block_header(xattr_ref);
 808                 block_data = (char *)block_header + block_size_rem;
 809                 block_size_rem -= sizeof(struct ext4_xattr_header);
 810
 811                 ext4_trans_set_block_dirty(xattr_ref->block.buf);
 812         } else {
 813                 /* We don't need an extra block.*/
 814                 if (xattr_ref->block_loaded) {
 815                         block_header = EXT4_XATTR_BHDR(&xattr_ref->block);
 816                         block_header->h_refcount =
 817                             to_le32(to_le32(block_header->h_refcount) - 1);
 818                         if (!block_header->h_refcount) {
 819                                 ext4_xattr_try_free_block(xattr_ref);
 820                                 block_header = NULL;
 821                         } else {
 822                                 block_entry =
 823                                     EXT4_XATTR_BFIRST(&xattr_ref->block);
 824                                 block_data =
 825                                     (char *)block_header + block_size_rem;
 826                                 block_size_rem -=
 827                                     sizeof(struct ext4_xattr_header);
 828                                 ext4_inode_set_file_acl(
 829                                     xattr_ref->inode_ref->inode,
 830                                     &xattr_ref->fs->sb, 0);
 831
 832                                 xattr_ref->inode_ref->dirty = true;
 833                                 ext4_trans_set_block_dirty(xattr_ref->block.buf);
 834                         }
 835                 }
 836         }
 837         RB_FOREACH_SAFE(item, ext4_xattr_tree, &xattr_ref->root, save_item)
 838         {
 839                 if (EXT4_XATTR_SIZE(item->data_size) +
 840                         EXT4_XATTR_LEN(item->name_len) <=
 841                     inode_size_rem) {
 842                         ibody_data = (char *)ibody_data -
 843                                      EXT4_XATTR_SIZE(item->data_size);
 844                         ext4_xattr_set_inode_entry(item, ibody_header, entry,
 845                                                    ibody_data);
 846                         memcpy(EXT4_XATTR_NAME(entry), item->name,
 847                                item->name_len);
 848                         memcpy(ibody_data, item->data, item->data_size);
 849                         entry = EXT4_XATTR_NEXT(entry);
 850                         inode_size_rem -= EXT4_XATTR_SIZE(item->data_size) +
 851                                           EXT4_XATTR_LEN(item->name_len);
 852
 853                         xattr_ref->inode_ref->dirty = true;
 854                         continue;
 855                 }
 856                 if (EXT4_XATTR_SIZE(item->data_size) +
 857                         EXT4_XATTR_LEN(item->name_len) >
 858                     block_size_rem) {
 859                         ret = ENOSPC;
 860                         ext4_dbg(DEBUG_XATTR, "IMPOSSIBLE ENOSPC AS WE DID INSPECTION!\n");
 861                         ext4_assert(0);
 862                 }
 863                 block_data =
 864                     (char *)block_data - EXT4_XATTR_SIZE(item->data_size);
 865                 ext4_xattr_set_block_entry(item, block_header, block_entry,
 866                                            block_data);
 867                 memcpy(EXT4_XATTR_NAME(block_entry), item->name,
 868                        item->name_len);
 869                 memcpy(block_data, item->data, item->data_size);
 870                 ext4_xattr_compute_hash(block_header, block_entry);
 871                 block_entry = EXT4_XATTR_NEXT(block_entry);
 872                 block_size_rem -= EXT4_XATTR_SIZE(item->data_size) +
 873                                   EXT4_XATTR_LEN(item->name_len);
 874
 875                 block_modified = true;
 876         }
 877         xattr_ref->dirty = false;
 878         if (block_modified) {
 879                 ext4_xattr_rehash(block_header,
 880                                   EXT4_XATTR_BFIRST(&xattr_ref->block));
 881                 ext4_xattr_set_block_checksum(xattr_ref->inode_ref,
 882                                               xattr_ref->block.lb_id,
 883                                               block_header);
 884                 ext4_trans_set_block_dirty(xattr_ref->block.buf);
 885         }
 886
 887 Finish:
 888         return ret;
 889 }
 890
 891 void ext4_fs_xattr_iterate(struct ext4_xattr_ref *ref,
 892                            int (*iter)(struct ext4_xattr_ref *ref,
 893                                      struct ext4_xattr_item *item))
 894 {
 895         struct ext4_xattr_item *item;
 896         if (!ref->iter_from)
 897                 ref->iter_from = RB_MIN(ext4_xattr_tree, &ref->root);
 898
 899         RB_FOREACH_FROM(item, ext4_xattr_tree, ref->iter_from)
 900         {
 901                 int ret = EXT4_XATTR_ITERATE_CONT;
 902                 if (iter)
 903                         iter(ref, item);
 904
 905                 if (ret != EXT4_XATTR_ITERATE_CONT) {
 906                         if (ret == EXT4_XATTR_ITERATE_STOP)
 907                                 ref->iter_from = NULL;
 908
 909                         break;
 910                 }
 911         }
 912 }
 913
 914 void ext4_fs_xattr_iterate_reset(struct ext4_xattr_ref *ref)
 915 {
 916         ref->iter_from = NULL;
 917 }
 918
 919 int ext4_fs_set_xattr(struct ext4_xattr_ref *ref, uint8_t name_index,
 920                       const char *name, size_t name_len, const void *data,
 921                       size_t data_size, bool replace)
 922 {
 923         int ret = EOK;
 924         struct ext4_xattr_item *item =
 925             ext4_xattr_lookup_item(ref, name_index, name, name_len);
 926         if (replace) {
 927                 if (!item) {
 928                         ret = ENODATA;
 929                         goto Finish;
 930                 }
 931                 if (item->data_size != data_size)
 932                         ret = ext4_xattr_resize_item(ref, item, data_size);
 933
 934                 if (ret != EOK) {
 935                         goto Finish;
 936                 }
 937                 memcpy(item->data, data, data_size);
 938         } else {
 939                 if (item) {
 940                         ret = EEXIST;
 941                         goto Finish;
 942                 }
 943                 item = ext4_xattr_insert_item(ref, name_index, name, name_len,
 944                                               data, data_size, &ret);
 945         }
 946 Finish:
 947         return ret;
 948 }
 949
 950 int ext4_fs_remove_xattr(struct ext4_xattr_ref *ref, uint8_t name_index,
 951                          const char *name, size_t name_len)
 952 {
 953         return ext4_xattr_remove_item(ref, name_index, name, name_len);
 954 }
 955
 956 int ext4_fs_get_xattr(struct ext4_xattr_ref *ref, uint8_t name_index,
 957                       const char *name, size_t name_len, void *buf,
 958                       size_t buf_size, size_t *data_size)
 959 {
 960         int ret = EOK;
 961         size_t item_size = 0;
 962         struct ext4_xattr_item *item =
 963             ext4_xattr_lookup_item(ref, name_index, name, name_len);
 964
 965         if (!item) {
 966                 ret = ENODATA;
 967                 goto Finish;
 968         }
 969         item_size = item->data_size;
 970         if (buf_size > item_size)
 971                 buf_size = item_size;
 972
 973         if (buf)
 974                 memcpy(buf, item->data, buf_size);
 975
 976 Finish:
 977         if (data_size)
 978                 *data_size = item_size;
 979
 980         return ret;
 981 }
 982
 983 int ext4_fs_get_xattr_ref(struct ext4_fs *fs, struct ext4_inode_ref *inode_ref,
 984                           struct ext4_xattr_ref *ref)
 985 {
 986         int rc;
 987         ext4_fsblk_t xattr_block;
 988         xattr_block = ext4_inode_get_file_acl(inode_ref->inode, &fs->sb);
 989         RB_INIT(&ref->root);
 990         ref->ea_size = 0;
 991         ref->iter_from = NULL;
 992         if (xattr_block) {
 993                 rc = ext4_trans_block_get(fs->bdev, &ref->block, xattr_block);
 994                 if (rc != EOK)
 995                         return EIO;
 996
 997                 ref->block_loaded = true;
 998         } else
 999                 ref->block_loaded = false;
1000
1001         ref->inode_ref = inode_ref;
1002         ref->fs = fs;
1003
1004         if (ext4_xattr_inode_space(ref) <
1005             sizeof(struct ext4_xattr_ibody_header))
1006                 ref->inode_size_rem = 0;
1007         else
1008                 ref->inode_size_rem =
1009                         ext4_xattr_inode_space(ref) -
1010                         sizeof(struct ext4_xattr_ibody_header);
1011
1012         ref->block_size_rem =
1013                 ext4_xattr_block_space(ref) -
1014                 sizeof(struct ext4_xattr_header);
1015
1016         rc = ext4_xattr_fetch(ref);
1017         if (rc != EOK) {
1018                 ext4_xattr_purge_items(ref);
1019                 if (xattr_block)
1020                         ext4_block_set(fs->bdev, &ref->block);
1021
1022                 ref->block_loaded = false;
1023                 return rc;
1024         }
1025         return EOK;
1026 }
1027
1028 void ext4_fs_put_xattr_ref(struct ext4_xattr_ref *ref)
1029 {
1030         int rc = ext4_xattr_write_to_disk(ref);
1031         if (ref->block_loaded) {
1032                 if (rc != EOK)
1033                         ext4_bcache_clear_dirty(ref->block.buf);
1034
1035                 ext4_block_set(ref->fs->bdev, &ref->block);
1036                 ref->block_loaded = false;
1037         }
1038         ext4_xattr_purge_items(ref);
1039         ref->inode_ref = NULL;
1040         ref->fs = NULL;
1041 }
1042
1043 struct xattr_prefix {
1044         const char *prefix;
1045         uint8_t name_index;
1046 };
1047
1048 static const struct xattr_prefix prefix_tbl[] = {
1049     {"user.", EXT4_XATTR_INDEX_USER},
1050     {"system.posix_acl_access", EXT4_XATTR_INDEX_POSIX_ACL_ACCESS},
1051     {"system.posix_acl_default", EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT},
1052     {"trusted.", EXT4_XATTR_INDEX_TRUSTED},
1053     {"security.", EXT4_XATTR_INDEX_SECURITY},
1054     {"system.", EXT4_XATTR_INDEX_SYSTEM},
1055     {"system.richacl", EXT4_XATTR_INDEX_RICHACL},
1056     {NULL, 0},
1057 };
1058
1059 const char *ext4_extract_xattr_name(const char *full_name, size_t full_name_len,
1060                               uint8_t *name_index, size_t *name_len,
1061                               bool *found)
1062 {
1063         int i;
1064         ext4_assert(name_index);
1065         ext4_assert(found);
1066
1067         *found = false;
1068
1069         if (!full_name_len) {
1070                 if (name_len)
1071                         *name_len = 0;
1072
1073                 return NULL;
1074         }
1075
1076         for (i = 0; prefix_tbl[i].prefix; i++) {
1077                 size_t prefix_len = strlen(prefix_tbl[i].prefix);
1078                 if (full_name_len >= prefix_len &&
1079                     !memcmp(full_name, prefix_tbl[i].prefix, prefix_len)) {
1080                         bool require_name =
1081                                 prefix_tbl[i].prefix[prefix_len - 1] == '.';
1082                         *name_index = prefix_tbl[i].name_index;
1083                         if (name_len)
1084                                 *name_len = full_name_len - prefix_len;
1085
1086                         if (!(full_name_len - prefix_len) && require_name)
1087                                 return NULL;
1088
1089                         *found = true;
1090                         if (require_name)
1091                                 return full_name + prefix_len;
1092
1093                         return NULL;
1094                 }
1095         }
1096         if (name_len)
1097                 *name_len = 0;
1098
1099         return NULL;
1100 }
1101
1102 const char *ext4_get_xattr_name_prefix(uint8_t name_index,
1103                                        size_t *ret_prefix_len)
1104 {
1105         int i;
1106
1107         for (i = 0; prefix_tbl[i].prefix; i++) {
1108                 size_t prefix_len = strlen(prefix_tbl[i].prefix);
1109                 if (prefix_tbl[i].name_index == name_index) {
1110                         if (ret_prefix_len)
1111                                 *ret_prefix_len = prefix_len;
1112
1113                         return prefix_tbl[i].prefix;
1114                 }
1115         }
1116         if (ret_prefix_len)
1117                 *ret_prefix_len = 0;
1118
1119         return NULL;
1120 }
1121
1122 /**
1123  * @}
1124  */