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         item->in_inode = true;
 462         if (xattr_ref->inode_size_rem <
 463             EXT4_XATTR_SIZE(data_size) +
 464             EXT4_XATTR_LEN(item->name_len)) {
 465                 if (xattr_ref->block_size_rem <
 466                     EXT4_XATTR_SIZE(data_size) +
 467                     EXT4_XATTR_LEN(item->name_len)) {
 468                         if (err)
 469                                 *err = ENOSPC;
 470
 471                         return NULL;
 472                 }
 473
 474                 item->in_inode = false;
 475         }
 476         if (ext4_xattr_item_alloc_data(item, data, data_size) != EOK) {
 477                 ext4_xattr_item_free(item);
 478                 if (err)
 479                         *err = ENOMEM;
 480
 481                 return NULL;
 482         }
 483         RB_INSERT(ext4_xattr_tree, &xattr_ref->root, item);
 484         xattr_ref->ea_size +=
 485             EXT4_XATTR_SIZE(item->data_size) + EXT4_XATTR_LEN(item->name_len);
 486         if (item->in_inode) {
 487                 xattr_ref->inode_size_rem -=
 488                         EXT4_XATTR_SIZE(item->data_size) +
 489                         EXT4_XATTR_LEN(item->name_len);
 490         } else {
 491                 xattr_ref->block_size_rem -=
 492                         EXT4_XATTR_SIZE(item->data_size) +
 493                         EXT4_XATTR_LEN(item->name_len);
 494         }
 495         xattr_ref->dirty = true;
 496         if (err)
 497                 *err = EOK;
 498
 499         return item;
 500 }
 501
 502 static int ext4_xattr_remove_item(struct ext4_xattr_ref *xattr_ref,
 503                                   uint8_t name_index, const char *name,
 504                                   size_t name_len)
 505 {
 506         int ret = ENOENT;
 507         struct ext4_xattr_item *item =
 508             ext4_xattr_lookup_item(xattr_ref, name_index, name, name_len);
 509         if (item) {
 510                 if (item == xattr_ref->iter_from)
 511                         xattr_ref->iter_from =
 512                             RB_NEXT(ext4_xattr_tree, &xattr_ref->root, item);
 513
 514                 xattr_ref->ea_size -= EXT4_XATTR_SIZE(item->data_size) +
 515                                       EXT4_XATTR_LEN(item->name_len);
 516
 517                 if (item->in_inode) {
 518                         xattr_ref->inode_size_rem +=
 519                                 EXT4_XATTR_SIZE(item->data_size) +
 520                                 EXT4_XATTR_LEN(item->name_len);
 521                 } else {
 522                         xattr_ref->block_size_rem +=
 523                                 EXT4_XATTR_SIZE(item->data_size) +
 524                                 EXT4_XATTR_LEN(item->name_len);
 525                 }
 526
 527                 RB_REMOVE(ext4_xattr_tree, &xattr_ref->root, item);
 528                 ext4_xattr_item_free(item);
 529                 xattr_ref->dirty = true;
 530                 ret = EOK;
 531         }
 532         return ret;
 533 }
 534
 535 static int ext4_xattr_resize_item(struct ext4_xattr_ref *xattr_ref,
 536                                   struct ext4_xattr_item *item,
 537                                   size_t new_data_size)
 538 {
 539         int ret = EOK;
 540         bool to_inode = false, to_block = false;
 541         size_t old_data_size = item->data_size;
 542         size_t orig_room_size = item->in_inode ?
 543                 xattr_ref->inode_size_rem :
 544                 xattr_ref->block_size_rem;
 545
 546         /*
 547          * Check if we can hold this entry in both in-inode and
 548          * on-block form.
 549          *
 550          * More complicated case: we do not allow entries stucking in
 551          * the middle between in-inode space and on-block space, so
 552          * the entry has to stay in either inode space or block space.
 553          */
 554         if (item->in_inode) {
 555                 if (xattr_ref->inode_size_rem +
 556                                 EXT4_XATTR_SIZE(old_data_size) <
 557                                 EXT4_XATTR_SIZE(new_data_size)) {
 558                         if (xattr_ref->block_size_rem <
 559                                         EXT4_XATTR_SIZE(new_data_size) +
 560                                         EXT4_XATTR_LEN(item->name_len))
 561                                 return ENOSPC;
 562
 563                         to_block = true;
 564                 }
 565         } else {
 566                 if (xattr_ref->block_size_rem +
 567                                 EXT4_XATTR_SIZE(old_data_size) <
 568                                 EXT4_XATTR_SIZE(new_data_size)) {
 569                         if (xattr_ref->inode_size_rem <
 570                                         EXT4_XATTR_SIZE(new_data_size) +
 571                                         EXT4_XATTR_LEN(item->name_len))
 572                                 return ENOSPC;
 573
 574                         to_inode = true;
 575                 }
 576         }
 577         ret = ext4_xattr_item_resize_data(item, new_data_size);
 578         if (ret != EOK)
 579                 return ret;
 580
 581         xattr_ref->ea_size =
 582             xattr_ref->ea_size -
 583             EXT4_XATTR_SIZE(old_data_size) +
 584             EXT4_XATTR_SIZE(new_data_size);
 585
 586         /*
 587          * This entry may originally lie in inode space or block space,
 588          * and it is going to be transferred to another place.
 589          */
 590         if (to_block) {
 591                 xattr_ref->inode_size_rem +=
 592                         EXT4_XATTR_SIZE(old_data_size) +
 593                         EXT4_XATTR_LEN(item->name_len);
 594                 xattr_ref->block_size_rem -=
 595                         EXT4_XATTR_SIZE(new_data_size) +
 596                         EXT4_XATTR_LEN(item->name_len);
 597                 item->in_inode = false;
 598         } else if (to_inode) {
 599                 xattr_ref->block_size_rem +=
 600                         EXT4_XATTR_SIZE(old_data_size) +
 601                         EXT4_XATTR_LEN(item->name_len);
 602                 xattr_ref->inode_size_rem -=
 603                         EXT4_XATTR_SIZE(new_data_size) +
 604                         EXT4_XATTR_LEN(item->name_len);
 605                 item->in_inode = true;
 606         } else {
 607                 /*
 608                  * No need to transfer as there is enough space for the entry
 609                  * to stay in inode space or block space it used to be.
 610                  */
 611                 orig_room_size +=
 612                         EXT4_XATTR_SIZE(old_data_size);
 613                 orig_room_size -=
 614                         EXT4_XATTR_SIZE(new_data_size);
 615                 if (item->in_inode)
 616                         xattr_ref->inode_size_rem = orig_room_size;
 617                 else
 618                         xattr_ref->block_size_rem = orig_room_size;
 619
 620         }
 621         xattr_ref->dirty = true;
 622         return ret;
 623 }
 624
 625 static void ext4_xattr_purge_items(struct ext4_xattr_ref *xattr_ref)
 626 {
 627         struct ext4_xattr_item *item, *save_item;
 628         RB_FOREACH_SAFE(item, ext4_xattr_tree, &xattr_ref->root, save_item) {
 629                 RB_REMOVE(ext4_xattr_tree, &xattr_ref->root, item);
 630                 ext4_xattr_item_free(item);
 631         }
 632         xattr_ref->ea_size = 0;
 633         if (ext4_xattr_inode_space(xattr_ref) <
 634             sizeof(struct ext4_xattr_ibody_header))
 635                 xattr_ref->inode_size_rem = 0;
 636         else
 637                 xattr_ref->inode_size_rem =
 638                         ext4_xattr_inode_space(xattr_ref) -
 639                         sizeof(struct ext4_xattr_ibody_header);
 640
 641         xattr_ref->block_size_rem =
 642                 ext4_xattr_block_space(xattr_ref) -
 643                 sizeof(struct ext4_xattr_header);
 644 }
 645
 646 static int ext4_xattr_try_alloc_block(struct ext4_xattr_ref *xattr_ref)
 647 {
 648         int ret = EOK;
 649
 650         ext4_fsblk_t xattr_block = 0;
 651         xattr_block = ext4_inode_get_file_acl(xattr_ref->inode_ref->inode,
 652                                               &xattr_ref->fs->sb);
 653         if (!xattr_block) {
 654                 ext4_fsblk_t goal =
 655                         ext4_fs_inode_to_goal_block(xattr_ref->inode_ref);
 656
 657                 ret = ext4_balloc_alloc_block(xattr_ref->inode_ref,
 658                                               goal,
 659                                               &xattr_block);
 660                 if (ret != EOK)
 661                         goto Finish;
 662
 663                 ret = ext4_trans_block_get(xattr_ref->fs->bdev, &xattr_ref->block,
 664                                      xattr_block);
 665                 if (ret != EOK) {
 666                         ext4_balloc_free_block(xattr_ref->inode_ref,
 667                                                xattr_block);
 668                         goto Finish;
 669                 }
 670
 671                 ext4_inode_set_file_acl(xattr_ref->inode_ref->inode,
 672                                         &xattr_ref->fs->sb, xattr_block);
 673                 xattr_ref->inode_ref->dirty = true;
 674                 xattr_ref->block_loaded = true;
 675         }
 676
 677 Finish:
 678         return ret;
 679 }
 680
 681 static void ext4_xattr_try_free_block(struct ext4_xattr_ref *xattr_ref)
 682 {
 683         ext4_fsblk_t xattr_block;
 684         xattr_block = ext4_inode_get_file_acl(xattr_ref->inode_ref->inode,
 685                                               &xattr_ref->fs->sb);
 686         ext4_inode_set_file_acl(xattr_ref->inode_ref->inode, &xattr_ref->fs->sb,
 687                                 0);
 688         ext4_block_set(xattr_ref->fs->bdev, &xattr_ref->block);
 689         ext4_balloc_free_block(xattr_ref->inode_ref, xattr_block);
 690         xattr_ref->inode_ref->dirty = true;
 691         xattr_ref->block_loaded = false;
 692 }
 693
 694 static void ext4_xattr_set_block_header(struct ext4_xattr_ref *xattr_ref)
 695 {
 696         struct ext4_xattr_header *block_header = NULL;
 697         block_header = EXT4_XATTR_BHDR(&xattr_ref->block);
 698
 699         memset(block_header, 0, sizeof(struct ext4_xattr_header));
 700         block_header->h_magic = EXT4_XATTR_MAGIC;
 701         block_header->h_refcount = to_le32(1);
 702         block_header->h_blocks = to_le32(1);
 703 }
 704
 705 static void
 706 ext4_xattr_set_inode_entry(struct ext4_xattr_item *item,
 707                            struct ext4_xattr_ibody_header *ibody_header,
 708                            struct ext4_xattr_entry *entry, void *ibody_data_ptr)
 709 {
 710         entry->e_name_len = (uint8_t)item->name_len;
 711         entry->e_name_index = item->name_index;
 712         entry->e_value_offs =
 713             to_le16((char *)ibody_data_ptr - (char *)EXT4_XATTR_IFIRST(ibody_header));
 714         entry->e_value_block = 0;
 715         entry->e_value_size = to_le32(item->data_size);
 716 }
 717
 718 static void ext4_xattr_set_block_entry(struct ext4_xattr_item *item,
 719                                        struct ext4_xattr_header *block_header,
 720                                        struct ext4_xattr_entry *block_entry,
 721                                        void *block_data_ptr)
 722 {
 723         block_entry->e_name_len = (uint8_t)item->name_len;
 724         block_entry->e_name_index = item->name_index;
 725         block_entry->e_value_offs =
 726             to_le16((char *)block_data_ptr - (char *)block_header);
 727         block_entry->e_value_block = 0;
 728         block_entry->e_value_size = to_le32(item->data_size);
 729 }
 730
 731 static int ext4_xattr_write_to_disk(struct ext4_xattr_ref *xattr_ref)
 732 {
 733         int ret = EOK;
 734         bool block_modified = false;
 735         void *ibody_data = NULL;
 736         void *block_data = NULL;
 737         struct ext4_xattr_item *item, *save_item;
 738         size_t inode_size_rem, block_size_rem;
 739         struct ext4_xattr_ibody_header *ibody_header = NULL;
 740         struct ext4_xattr_header *block_header = NULL;
 741         struct ext4_xattr_entry *entry = NULL;
 742         struct ext4_xattr_entry *block_entry = NULL;
 743
 744         inode_size_rem = ext4_xattr_inode_space(xattr_ref);
 745         block_size_rem = ext4_xattr_block_space(xattr_ref);
 746         if (inode_size_rem > sizeof(struct ext4_xattr_ibody_header)) {
 747                 ibody_header = EXT4_XATTR_IHDR(&xattr_ref->fs->sb,
 748                                                xattr_ref->inode_ref->inode);
 749                 entry = EXT4_XATTR_IFIRST(ibody_header);
 750         }
 751
 752         if (!xattr_ref->dirty)
 753                 goto Finish;
 754         /* If there are enough spaces in the ibody EA table.*/
 755         if (inode_size_rem > sizeof(struct ext4_xattr_ibody_header)) {
 756                 memset(ibody_header, 0, inode_size_rem);
 757                 ibody_header->h_magic = EXT4_XATTR_MAGIC;
 758                 ibody_data = (char *)ibody_header + inode_size_rem;
 759                 inode_size_rem -= sizeof(struct ext4_xattr_ibody_header);
 760
 761                 xattr_ref->inode_ref->dirty = true;
 762         }
 763         /* If we need an extra block to hold the EA entries*/
 764         if (xattr_ref->ea_size > inode_size_rem) {
 765                 if (!xattr_ref->block_loaded) {
 766                         ret = ext4_xattr_try_alloc_block(xattr_ref);
 767                         if (ret != EOK)
 768                                 goto Finish;
 769                 }
 770                 memset(xattr_ref->block.data, 0,
 771                        ext4_sb_get_block_size(&xattr_ref->fs->sb));
 772                 block_header = EXT4_XATTR_BHDR(&xattr_ref->block);
 773                 block_entry = EXT4_XATTR_BFIRST(&xattr_ref->block);
 774                 ext4_xattr_set_block_header(xattr_ref);
 775                 block_data = (char *)block_header + block_size_rem;
 776                 block_size_rem -= sizeof(struct ext4_xattr_header);
 777
 778                 ext4_trans_set_block_dirty(xattr_ref->block.buf);
 779         } else {
 780                 /* We don't need an extra block.*/
 781                 if (xattr_ref->block_loaded) {
 782                         block_header = EXT4_XATTR_BHDR(&xattr_ref->block);
 783                         block_header->h_refcount =
 784                             to_le32(to_le32(block_header->h_refcount) - 1);
 785                         if (!block_header->h_refcount) {
 786                                 ext4_xattr_try_free_block(xattr_ref);
 787                                 block_header = NULL;
 788                         } else {
 789                                 block_entry =
 790                                     EXT4_XATTR_BFIRST(&xattr_ref->block);
 791                                 block_data =
 792                                     (char *)block_header + block_size_rem;
 793                                 block_size_rem -=
 794                                     sizeof(struct ext4_xattr_header);
 795                                 ext4_inode_set_file_acl(
 796                                     xattr_ref->inode_ref->inode,
 797                                     &xattr_ref->fs->sb, 0);
 798
 799                                 xattr_ref->inode_ref->dirty = true;
 800                                 ext4_trans_set_block_dirty(xattr_ref->block.buf);
 801                         }
 802                 }
 803         }
 804         RB_FOREACH_SAFE(item, ext4_xattr_tree, &xattr_ref->root, save_item)
 805         {
 806                 if (item->in_inode) {
 807                         ibody_data = (char *)ibody_data -
 808                                      EXT4_XATTR_SIZE(item->data_size);
 809                         ext4_xattr_set_inode_entry(item, ibody_header, entry,
 810                                                    ibody_data);
 811                         memcpy(EXT4_XATTR_NAME(entry), item->name,
 812                                item->name_len);
 813                         memcpy(ibody_data, item->data, item->data_size);
 814                         entry = EXT4_XATTR_NEXT(entry);
 815                         inode_size_rem -= EXT4_XATTR_SIZE(item->data_size) +
 816                                           EXT4_XATTR_LEN(item->name_len);
 817
 818                         xattr_ref->inode_ref->dirty = true;
 819                         continue;
 820                 }
 821                 if (EXT4_XATTR_SIZE(item->data_size) +
 822                         EXT4_XATTR_LEN(item->name_len) >
 823                     block_size_rem) {
 824                         ret = ENOSPC;
 825                         ext4_dbg(DEBUG_XATTR, "IMPOSSIBLE ENOSPC AS WE DID INSPECTION!\n");
 826                         ext4_assert(0);
 827                 }
 828                 block_data =
 829                     (char *)block_data - EXT4_XATTR_SIZE(item->data_size);
 830                 ext4_xattr_set_block_entry(item, block_header, block_entry,
 831                                            block_data);
 832                 memcpy(EXT4_XATTR_NAME(block_entry), item->name,
 833                        item->name_len);
 834                 memcpy(block_data, item->data, item->data_size);
 835                 ext4_xattr_compute_hash(block_header, block_entry);
 836                 block_entry = EXT4_XATTR_NEXT(block_entry);
 837                 block_size_rem -= EXT4_XATTR_SIZE(item->data_size) +
 838                                   EXT4_XATTR_LEN(item->name_len);
 839
 840                 block_modified = true;
 841         }
 842         xattr_ref->dirty = false;
 843         if (block_modified) {
 844                 ext4_xattr_rehash(block_header,
 845                                   EXT4_XATTR_BFIRST(&xattr_ref->block));
 846                 ext4_xattr_set_block_checksum(xattr_ref->inode_ref,
 847                                               xattr_ref->block.lb_id,
 848                                               block_header);
 849                 ext4_trans_set_block_dirty(xattr_ref->block.buf);
 850         }
 851
 852 Finish:
 853         return ret;
 854 }
 855
 856 void ext4_fs_xattr_iterate(struct ext4_xattr_ref *ref,
 857                            int (*iter)(struct ext4_xattr_ref *ref,
 858                                      struct ext4_xattr_item *item))
 859 {
 860         struct ext4_xattr_item *item;
 861         if (!ref->iter_from)
 862                 ref->iter_from = RB_MIN(ext4_xattr_tree, &ref->root);
 863
 864         RB_FOREACH_FROM(item, ext4_xattr_tree, ref->iter_from)
 865         {
 866                 int ret = EXT4_XATTR_ITERATE_CONT;
 867                 if (iter)
 868                         iter(ref, item);
 869
 870                 if (ret != EXT4_XATTR_ITERATE_CONT) {
 871                         if (ret == EXT4_XATTR_ITERATE_STOP)
 872                                 ref->iter_from = NULL;
 873
 874                         break;
 875                 }
 876         }
 877 }
 878
 879 void ext4_fs_xattr_iterate_reset(struct ext4_xattr_ref *ref)
 880 {
 881         ref->iter_from = NULL;
 882 }
 883
 884 int ext4_fs_set_xattr(struct ext4_xattr_ref *ref, uint8_t name_index,
 885                       const char *name, size_t name_len, const void *data,
 886                       size_t data_size, bool replace)
 887 {
 888         int ret = EOK;
 889         struct ext4_xattr_item *item =
 890             ext4_xattr_lookup_item(ref, name_index, name, name_len);
 891         if (replace) {
 892                 if (!item) {
 893                         ret = ENODATA;
 894                         goto Finish;
 895                 }
 896                 if (item->data_size != data_size)
 897                         ret = ext4_xattr_resize_item(ref, item, data_size);
 898
 899                 if (ret != EOK) {
 900                         goto Finish;
 901                 }
 902                 memcpy(item->data, data, data_size);
 903         } else {
 904                 if (item) {
 905                         ret = EEXIST;
 906                         goto Finish;
 907                 }
 908                 item = ext4_xattr_insert_item(ref, name_index, name, name_len,
 909                                               data, data_size, &ret);
 910         }
 911 Finish:
 912         return ret;
 913 }
 914
 915 int ext4_fs_remove_xattr(struct ext4_xattr_ref *ref, uint8_t name_index,
 916                          const char *name, size_t name_len)
 917 {
 918         return ext4_xattr_remove_item(ref, name_index, name, name_len);
 919 }
 920
 921 int ext4_fs_get_xattr(struct ext4_xattr_ref *ref, uint8_t name_index,
 922                       const char *name, size_t name_len, void *buf,
 923                       size_t buf_size, size_t *data_size)
 924 {
 925         int ret = EOK;
 926         size_t item_size = 0;
 927         struct ext4_xattr_item *item =
 928             ext4_xattr_lookup_item(ref, name_index, name, name_len);
 929
 930         if (!item) {
 931                 ret = ENODATA;
 932                 goto Finish;
 933         }
 934         item_size = item->data_size;
 935         if (buf_size > item_size)
 936                 buf_size = item_size;
 937
 938         if (buf)
 939                 memcpy(buf, item->data, buf_size);
 940
 941 Finish:
 942         if (data_size)
 943                 *data_size = item_size;
 944
 945         return ret;
 946 }
 947
 948 int ext4_fs_get_xattr_ref(struct ext4_fs *fs, struct ext4_inode_ref *inode_ref,
 949                           struct ext4_xattr_ref *ref)
 950 {
 951         int rc;
 952         ext4_fsblk_t xattr_block;
 953         xattr_block = ext4_inode_get_file_acl(inode_ref->inode, &fs->sb);
 954         RB_INIT(&ref->root);
 955         ref->ea_size = 0;
 956         ref->iter_from = NULL;
 957         if (xattr_block) {
 958                 rc = ext4_trans_block_get(fs->bdev, &ref->block, xattr_block);
 959                 if (rc != EOK)
 960                         return EIO;
 961
 962                 ref->block_loaded = true;
 963         } else
 964                 ref->block_loaded = false;
 965
 966         ref->inode_ref = inode_ref;
 967         ref->fs = fs;
 968
 969         if (ext4_xattr_inode_space(ref) <
 970             sizeof(struct ext4_xattr_ibody_header))
 971                 ref->inode_size_rem = 0;
 972         else
 973                 ref->inode_size_rem =
 974                         ext4_xattr_inode_space(ref) -
 975                         sizeof(struct ext4_xattr_ibody_header);
 976
 977         ref->block_size_rem =
 978                 ext4_xattr_block_space(ref) -
 979                 sizeof(struct ext4_xattr_header);
 980
 981         rc = ext4_xattr_fetch(ref);
 982         if (rc != EOK) {
 983                 ext4_xattr_purge_items(ref);
 984                 if (xattr_block)
 985                         ext4_block_set(fs->bdev, &ref->block);
 986
 987                 ref->block_loaded = false;
 988                 return rc;
 989         }
 990         return EOK;
 991 }
 992
 993 void ext4_fs_put_xattr_ref(struct ext4_xattr_ref *ref)
 994 {
 995         int rc = ext4_xattr_write_to_disk(ref);
 996         if (ref->block_loaded) {
 997                 if (rc != EOK)
 998                         ext4_bcache_clear_dirty(ref->block.buf);
 999
1000                 ext4_block_set(ref->fs->bdev, &ref->block);
1001                 ref->block_loaded = false;
1002         }
1003         ext4_xattr_purge_items(ref);
1004         ref->inode_ref = NULL;
1005         ref->fs = NULL;
1006 }
1007
1008 struct xattr_prefix {
1009         const char *prefix;
1010         uint8_t name_index;
1011 };
1012
1013 static const struct xattr_prefix prefix_tbl[] = {
1014     {"user.", EXT4_XATTR_INDEX_USER},
1015     {"system.posix_acl_access", EXT4_XATTR_INDEX_POSIX_ACL_ACCESS},
1016     {"system.posix_acl_default", EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT},
1017     {"trusted.", EXT4_XATTR_INDEX_TRUSTED},
1018     {"security.", EXT4_XATTR_INDEX_SECURITY},
1019     {"system.", EXT4_XATTR_INDEX_SYSTEM},
1020     {"system.richacl", EXT4_XATTR_INDEX_RICHACL},
1021     {NULL, 0},
1022 };
1023
1024 const char *ext4_extract_xattr_name(const char *full_name, size_t full_name_len,
1025                               uint8_t *name_index, size_t *name_len,
1026                               bool *found)
1027 {
1028         int i;
1029         ext4_assert(name_index);
1030         ext4_assert(found);
1031
1032         *found = false;
1033
1034         if (!full_name_len) {
1035                 if (name_len)
1036                         *name_len = 0;
1037
1038                 return NULL;
1039         }
1040
1041         for (i = 0; prefix_tbl[i].prefix; i++) {
1042                 size_t prefix_len = strlen(prefix_tbl[i].prefix);
1043                 if (full_name_len >= prefix_len &&
1044                     !memcmp(full_name, prefix_tbl[i].prefix, prefix_len)) {
1045                         bool require_name =
1046                                 prefix_tbl[i].prefix[prefix_len - 1] == '.';
1047                         *name_index = prefix_tbl[i].name_index;
1048                         if (name_len)
1049                                 *name_len = full_name_len - prefix_len;
1050
1051                         if (!(full_name_len - prefix_len) && require_name)
1052                                 return NULL;
1053
1054                         *found = true;
1055                         if (require_name)
1056                                 return full_name + prefix_len;
1057
1058                         return NULL;
1059                 }
1060         }
1061         if (name_len)
1062                 *name_len = 0;
1063
1064         return NULL;
1065 }
1066
1067 const char *ext4_get_xattr_name_prefix(uint8_t name_index,
1068                                        size_t *ret_prefix_len)
1069 {
1070         int i;
1071
1072         for (i = 0; prefix_tbl[i].prefix; i++) {
1073                 size_t prefix_len = strlen(prefix_tbl[i].prefix);
1074                 if (prefix_tbl[i].name_index == name_index) {
1075                         if (ret_prefix_len)
1076                                 *ret_prefix_len = prefix_len;
1077
1078                         return prefix_tbl[i].prefix;
1079                 }
1080         }
1081         if (ret_prefix_len)
1082                 *ret_prefix_len = 0;
1083
1084         return NULL;
1085 }
1086
1087 /**
1088  * @}
1089  */