lwext4/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_fs.h"
  40 #include "ext4_errno.h"
  41 #include "ext4_blockdev.h"
  42 #include "ext4_super.h"
  43 #include "ext4_crc32c.h"
  44 #include "ext4_debug.h"
  45 #include "ext4_block_group.h"
  46 #include "ext4_balloc.h"
  47 #include "ext4_inode.h"
  48
  49 #include <string.h>
  50 #include <stdlib.h>
  51
  52 /**
  53  * @file  ext4_xattr.c
  54  * @brief Extended Attribute Manipulation
  55  */
  56
  57 #define NAME_HASH_SHIFT 5
  58 #define VALUE_HASH_SHIFT 16
  59
  60 static inline void ext4_xattr_compute_hash(struct ext4_xattr_header *header,
  61                                            struct ext4_xattr_entry *entry)
  62 {
  63         uint32_t hash = 0;
  64         char *name = EXT4_XATTR_NAME(entry);
  65         int n;
  66
  67         for (n = 0; n < entry->e_name_len; n++) {
  68                 hash = (hash << NAME_HASH_SHIFT) ^
  69                        (hash >> (8 * sizeof(hash) - NAME_HASH_SHIFT)) ^ *name++;
  70         }
  71
  72         if (entry->e_value_block == 0 && entry->e_value_size != 0) {
  73                 uint32_t *value =
  74                     (uint32_t *)((char *)header + to_le16(entry->e_value_offs));
  75                 for (n = (to_le32(entry->e_value_size) + EXT4_XATTR_ROUND) >>
  76                          EXT4_XATTR_PAD_BITS;
  77                      n; n--) {
  78                         hash = (hash << VALUE_HASH_SHIFT) ^
  79                                (hash >> (8 * sizeof(hash) - VALUE_HASH_SHIFT)) ^
  80                                to_le32(*value++);
  81                 }
  82         }
  83         entry->e_hash = to_le32(hash);
  84 }
  85
  86 #define BLOCK_HASH_SHIFT 16
  87
  88 /*
  89  * ext4_xattr_rehash()
  90  *
  91  * Re-compute the extended attribute hash value after an entry has changed.
  92  */
  93 static void ext4_xattr_rehash(struct ext4_xattr_header *header,
  94                               struct ext4_xattr_entry *entry)
  95 {
  96         struct ext4_xattr_entry *here;
  97         uint32_t hash = 0;
  98
  99         ext4_xattr_compute_hash(header, entry);
 100         here = EXT4_XATTR_ENTRY(header + 1);
 101         while (!EXT4_XATTR_IS_LAST_ENTRY(here)) {
 102                 if (!here->e_hash) {
 103                         /* Block is not shared if an entry's hash value == 0 */
 104                         hash = 0;
 105                         break;
 106                 }
 107                 hash = (hash << BLOCK_HASH_SHIFT) ^
 108                        (hash >> (8 * sizeof(hash) - BLOCK_HASH_SHIFT)) ^
 109                        to_le32(here->e_hash);
 110                 here = EXT4_XATTR_NEXT(here);
 111         }
 112         header->h_hash = to_le32(hash);
 113 }
 114
 115 static uint32_t
 116 ext4_xattr_block_checksum(struct ext4_inode_ref *inode_ref,
 117                           ext4_fsblk_t blocknr,
 118                           struct ext4_xattr_header *header)
 119 {
 120         uint32_t checksum = 0;
 121         uint64_t le64_blocknr = blocknr;
 122         struct ext4_sblock *sb = &inode_ref->fs->sb;
 123
 124         if (ext4_sb_has_feature_read_only(sb,
 125                                 EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) {
 126                 uint32_t orig_checksum;
 127
 128                 /* Preparation: temporarily set bg checksum to 0 */
 129                 orig_checksum = header->h_checksum;
 130                 header->h_checksum = 0;
 131                 /* First calculate crc32 checksum against fs uuid */
 132                 checksum = ext4_crc32c(~0, sb->uuid, sizeof(sb->uuid));
 133                 /* Then calculate crc32 checksum block number */
 134                 checksum = ext4_crc32c(checksum, &le64_blocknr,
 135                                      sizeof(le64_blocknr));
 136                 /* Finally calculate crc32 checksum against
 137                  * the entire xattr block */
 138                 checksum = ext4_crc32c(checksum, header,
 139                                    ext4_sb_get_block_size(sb));
 140                 header->h_checksum = orig_checksum;
 141         }
 142         return checksum;
 143 }
 144
 145 static void
 146 ext4_xattr_set_block_checksum(struct ext4_inode_ref *inode_ref,
 147                               ext4_fsblk_t blocknr,
 148                               struct ext4_xattr_header *header)
 149 {
 150         struct ext4_sblock *sb = &inode_ref->fs->sb;
 151         if (!ext4_sb_has_feature_read_only(sb,
 152                                 EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
 153                 return;
 154
 155         header->h_checksum =
 156                 ext4_xattr_block_checksum(inode_ref, blocknr, header);
 157 }
 158
 159 static int ext4_xattr_item_cmp(struct ext4_xattr_item *a,
 160                                struct ext4_xattr_item *b)
 161 {
 162         int result;
 163         result = a->name_index - b->name_index;
 164         if (result)
 165                 return result;
 166
 167         result = a->name_len - b->name_len;
 168         if (result)
 169                 return result;
 170
 171         return memcmp(a->name, b->name, a->name_len);
 172 }
 173
 174 RB_GENERATE_INTERNAL(ext4_xattr_tree, ext4_xattr_item, node,
 175                      ext4_xattr_item_cmp, static inline)
 176
 177 static struct ext4_xattr_item *
 178 ext4_xattr_item_alloc(uint8_t name_index, const char *name, size_t name_len)
 179 {
 180         struct ext4_xattr_item *item;
 181         item = malloc(sizeof(struct ext4_xattr_item) + name_len);
 182         if (!item)
 183                 return NULL;
 184
 185         item->name_index = name_index;
 186         item->name = (char *)(item + 1);
 187         item->name_len = name_len;
 188         item->data = NULL;
 189         item->data_size = 0;
 190
 191         memset(&item->node, 0, sizeof(item->node));
 192         memcpy(item->name, name, name_len);
 193
 194         return item;
 195 }
 196
 197 static int ext4_xattr_item_alloc_data(struct ext4_xattr_item *item,
 198                                       const void *orig_data, size_t data_size)
 199 {
 200         void *data = NULL;
 201         ext4_assert(!item->data);
 202         data = malloc(data_size);
 203         if (!data)
 204                 return ENOMEM;
 205
 206         if (orig_data)
 207                 memcpy(data, orig_data, data_size);
 208
 209         item->data = data;
 210         item->data_size = data_size;
 211         return EOK;
 212 }
 213
 214 static void ext4_xattr_item_free_data(struct ext4_xattr_item *item)
 215 {
 216         ext4_assert(item->data);
 217         free(item->data);
 218         item->data = NULL;
 219         item->data_size = 0;
 220 }
 221
 222 static int ext4_xattr_item_resize_data(struct ext4_xattr_item *item,
 223                                        size_t new_data_size)
 224 {
 225         if (new_data_size != item->data_size) {
 226                 void *new_data;
 227                 new_data = realloc(item->data, new_data_size);
 228                 if (!new_data)
 229                         return ENOMEM;
 230
 231                 item->data = new_data;
 232                 item->data_size = new_data_size;
 233         }
 234         return EOK;
 235 }
 236
 237 static void ext4_xattr_item_free(struct ext4_xattr_item *item)
 238 {
 239         if (item->data)
 240                 ext4_xattr_item_free_data(item);
 241
 242         free(item);
 243 }
 244
 245 static void *ext4_xattr_entry_data(struct ext4_xattr_ref *xattr_ref,
 246                                    struct ext4_xattr_entry *entry,
 247                                    bool in_inode)
 248 {
 249         char *ret;
 250         if (in_inode) {
 251                 struct ext4_xattr_ibody_header *header;
 252                 struct ext4_xattr_entry *first_entry;
 253                 int16_t inode_size =
 254                     ext4_get16(&xattr_ref->fs->sb, inode_size);
 255                 header = EXT4_XATTR_IHDR(xattr_ref->inode_ref->inode);
 256                 first_entry = EXT4_XATTR_IFIRST(header);
 257
 258                 ret = ((char *)first_entry + to_le16(entry->e_value_offs));
 259                 if (ret + EXT4_XATTR_SIZE(to_le32(entry->e_value_size)) -
 260                         (char *)xattr_ref->inode_ref->inode > inode_size)
 261                         ret = NULL;
 262
 263                 return ret;
 264
 265         }
 266         int32_t block_size = ext4_sb_get_block_size(&xattr_ref->fs->sb);
 267         ret = ((char *)xattr_ref->block.data + to_le16(entry->e_value_offs));
 268         if (ret + EXT4_XATTR_SIZE(to_le32(entry->e_value_size)) -
 269                         (char *)xattr_ref->block.data > block_size)
 270                 ret = NULL;
 271         return ret;
 272 }
 273
 274 static int ext4_xattr_block_fetch(struct ext4_xattr_ref *xattr_ref)
 275 {
 276         int ret = EOK;
 277         size_t size_rem;
 278         void *data;
 279         struct ext4_xattr_entry *entry = NULL;
 280
 281         ext4_assert(xattr_ref->block.data);
 282         entry = EXT4_XATTR_BFIRST(&xattr_ref->block);
 283
 284         size_rem = ext4_sb_get_block_size(&xattr_ref->fs->sb);
 285         for (; size_rem > 0 && !EXT4_XATTR_IS_LAST_ENTRY(entry);
 286              entry = EXT4_XATTR_NEXT(entry),
 287              size_rem -= EXT4_XATTR_LEN(entry->e_name_len)) {
 288                 struct ext4_xattr_item *item;
 289                 char *e_name = EXT4_XATTR_NAME(entry);
 290
 291                 data = ext4_xattr_entry_data(xattr_ref, entry, false);
 292                 if (!data) {
 293                         ret = EIO;
 294                         goto Finish;
 295                 }
 296
 297                 item = ext4_xattr_item_alloc(entry->e_name_index, e_name,
 298                                              (size_t)entry->e_name_len);
 299                 if (!item) {
 300                         ret = ENOMEM;
 301                         goto Finish;
 302                 }
 303                 if (ext4_xattr_item_alloc_data(
 304                         item, data, to_le32(entry->e_value_size)) != EOK) {
 305                         ext4_xattr_item_free(item);
 306                         ret = ENOMEM;
 307                         goto Finish;
 308                 }
 309                 RB_INSERT(ext4_xattr_tree, &xattr_ref->root, item);
 310                 xattr_ref->ea_size += EXT4_XATTR_SIZE(item->data_size) +
 311                                       EXT4_XATTR_LEN(item->name_len);
 312         }
 313
 314 Finish:
 315         return ret;
 316 }
 317
 318 static int ext4_xattr_inode_fetch(struct ext4_xattr_ref *xattr_ref)
 319 {
 320         void *data;
 321         size_t size_rem;
 322         int ret = EOK;
 323         struct ext4_xattr_ibody_header *header = NULL;
 324         struct ext4_xattr_entry *entry = NULL;
 325         uint16_t inode_size = ext4_get16(&xattr_ref->fs->sb, inode_size);
 326
 327         header = EXT4_XATTR_IHDR(xattr_ref->inode_ref->inode);
 328         entry = EXT4_XATTR_IFIRST(header);
 329
 330         size_rem = inode_size - EXT4_GOOD_OLD_INODE_SIZE -
 331                    xattr_ref->inode_ref->inode->extra_isize;
 332         for (; size_rem > 0 && !EXT4_XATTR_IS_LAST_ENTRY(entry);
 333              entry = EXT4_XATTR_NEXT(entry),
 334              size_rem -= EXT4_XATTR_LEN(entry->e_name_len)) {
 335                 struct ext4_xattr_item *item;
 336                 char *e_name = EXT4_XATTR_NAME(entry);
 337
 338                 data = ext4_xattr_entry_data(xattr_ref, entry, true);
 339                 if (!data) {
 340                         ret = EIO;
 341                         goto Finish;
 342                 }
 343
 344                 item = ext4_xattr_item_alloc(entry->e_name_index, e_name,
 345                                              (size_t)entry->e_name_len);
 346                 if (!item) {
 347                         ret = ENOMEM;
 348                         goto Finish;
 349                 }
 350                 if (ext4_xattr_item_alloc_data(
 351                         item, data, to_le32(entry->e_value_size)) != EOK) {
 352                         ext4_xattr_item_free(item);
 353                         ret = ENOMEM;
 354                         goto Finish;
 355                 }
 356                 RB_INSERT(ext4_xattr_tree, &xattr_ref->root, item);
 357                 xattr_ref->ea_size += EXT4_XATTR_SIZE(item->data_size) +
 358                                       EXT4_XATTR_LEN(item->name_len);
 359         }
 360
 361 Finish:
 362         return ret;
 363 }
 364
 365 static size_t ext4_xattr_inode_space(struct ext4_xattr_ref *xattr_ref)
 366 {
 367         uint16_t inode_size = ext4_get16(&xattr_ref->fs->sb, inode_size);
 368         uint16_t size_rem = inode_size - EXT4_GOOD_OLD_INODE_SIZE -
 369                             xattr_ref->inode_ref->inode->extra_isize;
 370         return size_rem;
 371 }
 372
 373 static size_t ext4_xattr_block_space(struct ext4_xattr_ref *xattr_ref)
 374 {
 375         return ext4_sb_get_block_size(&xattr_ref->fs->sb);
 376 }
 377
 378 static int ext4_xattr_fetch(struct ext4_xattr_ref *xattr_ref)
 379 {
 380         int ret = EOK;
 381         uint16_t inode_size = ext4_get16(&xattr_ref->fs->sb, inode_size);
 382         if (inode_size > EXT4_GOOD_OLD_INODE_SIZE) {
 383                 ret = ext4_xattr_inode_fetch(xattr_ref);
 384                 if (ret != EOK)
 385                         return ret;
 386         }
 387
 388         if (xattr_ref->block_loaded)
 389                 ret = ext4_xattr_block_fetch(xattr_ref);
 390
 391         xattr_ref->dirty = false;
 392         return ret;
 393 }
 394
 395 static struct ext4_xattr_item *
 396 ext4_xattr_lookup_item(struct ext4_xattr_ref *xattr_ref, uint8_t name_index,
 397                        const char *name, size_t name_len)
 398 {
 399         struct ext4_xattr_item tmp = {
 400                 .name_index = name_index,
 401                 .name = (char *)name, /*RB_FIND - won't touch this string*/
 402                 .name_len = name_len,
 403         };
 404
 405         return RB_FIND(ext4_xattr_tree, &xattr_ref->root, &tmp);
 406 }
 407
 408 static struct ext4_xattr_item *
 409 ext4_xattr_insert_item(struct ext4_xattr_ref *xattr_ref, uint8_t name_index,
 410                        const char *name, size_t name_len, const void *data,
 411                        size_t data_size)
 412 {
 413         struct ext4_xattr_item *item;
 414         item = ext4_xattr_item_alloc(name_index, name, name_len);
 415         if (!item)
 416                 return NULL;
 417
 418         if ((xattr_ref->ea_size + EXT4_XATTR_SIZE(data_size) +
 419                 EXT4_XATTR_LEN(item->name_len)
 420                         >
 421             ext4_xattr_inode_space(xattr_ref) -
 422                 sizeof(struct ext4_xattr_ibody_header))
 423                 &&
 424             (xattr_ref->ea_size + EXT4_XATTR_SIZE(data_size) +
 425                 EXT4_XATTR_LEN(item->name_len) >
 426             ext4_xattr_block_space(xattr_ref) -
 427                 sizeof(struct ext4_xattr_header))) {
 428                 ext4_xattr_item_free(item);
 429
 430                 return NULL;
 431         }
 432         if (ext4_xattr_item_alloc_data(item, data, data_size) != EOK) {
 433                 ext4_xattr_item_free(item);
 434                 return NULL;
 435         }
 436         RB_INSERT(ext4_xattr_tree, &xattr_ref->root, item);
 437         xattr_ref->ea_size +=
 438             EXT4_XATTR_SIZE(item->data_size) + EXT4_XATTR_LEN(item->name_len);
 439         xattr_ref->dirty = true;
 440         return item;
 441 }
 442
 443 static int ext4_xattr_remove_item(struct ext4_xattr_ref *xattr_ref,
 444                                   uint8_t name_index, const char *name,
 445                                   size_t name_len)
 446 {
 447         int ret = ENOENT;
 448         struct ext4_xattr_item *item =
 449             ext4_xattr_lookup_item(xattr_ref, name_index, name, name_len);
 450         if (item) {
 451                 if (item == xattr_ref->iter_from)
 452                         xattr_ref->iter_from =
 453                             RB_NEXT(ext4_xattr_tree, &xattr_ref->root, item);
 454
 455                 xattr_ref->ea_size -= EXT4_XATTR_SIZE(item->data_size) +
 456                                       EXT4_XATTR_LEN(item->name_len);
 457
 458                 RB_REMOVE(ext4_xattr_tree, &xattr_ref->root, item);
 459                 ext4_xattr_item_free(item);
 460                 xattr_ref->dirty = true;
 461                 ret = EOK;
 462         }
 463         return ret;
 464 }
 465
 466 static int ext4_xattr_resize_item(struct ext4_xattr_ref *xattr_ref,
 467                                   struct ext4_xattr_item *item,
 468                                   size_t new_data_size)
 469 {
 470         int ret = EOK;
 471         size_t old_data_size = item->data_size;
 472         if ((xattr_ref->ea_size - EXT4_XATTR_SIZE(old_data_size) +
 473                 EXT4_XATTR_SIZE(new_data_size)
 474                         >
 475             ext4_xattr_inode_space(xattr_ref) -
 476                 sizeof(struct ext4_xattr_ibody_header))
 477                 &&
 478             (xattr_ref->ea_size - EXT4_XATTR_SIZE(old_data_size) +
 479                 EXT4_XATTR_SIZE(new_data_size)
 480                         >
 481             ext4_xattr_block_space(xattr_ref) -
 482                 sizeof(struct ext4_xattr_header))) {
 483
 484                 return ENOSPC;
 485         }
 486         ret = ext4_xattr_item_resize_data(item, new_data_size);
 487         if (ret != EOK) {
 488                 return ret;
 489         }
 490         xattr_ref->ea_size =
 491             xattr_ref->ea_size -
 492             EXT4_XATTR_SIZE(old_data_size) +
 493             EXT4_XATTR_SIZE(new_data_size);
 494         xattr_ref->dirty = true;
 495         return ret;
 496 }
 497
 498 static void ext4_xattr_purge_items(struct ext4_xattr_ref *xattr_ref)
 499 {
 500         struct ext4_xattr_item *item, *save_item;
 501         RB_FOREACH_SAFE(item, ext4_xattr_tree, &xattr_ref->root, save_item)
 502         {
 503                 RB_REMOVE(ext4_xattr_tree, &xattr_ref->root, item);
 504                 ext4_xattr_item_free(item);
 505         }
 506         xattr_ref->ea_size = 0;
 507 }
 508
 509 static int ext4_xattr_try_alloc_block(struct ext4_xattr_ref *xattr_ref)
 510 {
 511         int ret = EOK;
 512
 513         ext4_fsblk_t xattr_block = 0;
 514         xattr_block = ext4_inode_get_file_acl(xattr_ref->inode_ref->inode,
 515                                               &xattr_ref->fs->sb);
 516         if (!xattr_block) {
 517                 ext4_fsblk_t goal =
 518                         ext4_fs_inode_to_goal_block(xattr_ref->inode_ref);
 519
 520                 ret = ext4_balloc_alloc_block(xattr_ref->inode_ref,
 521                                               goal,
 522                                               &xattr_block);
 523                 if (ret != EOK)
 524                         goto Finish;
 525
 526                 ret = ext4_block_get(xattr_ref->fs->bdev, &xattr_ref->block,
 527                                      xattr_block);
 528                 if (ret != EOK) {
 529                         ext4_balloc_free_block(xattr_ref->inode_ref,
 530                                                xattr_block);
 531                         goto Finish;
 532                 }
 533
 534                 ext4_inode_set_file_acl(xattr_ref->inode_ref->inode,
 535                                         &xattr_ref->fs->sb, xattr_block);
 536                 xattr_ref->inode_ref->dirty = true;
 537                 xattr_ref->block_loaded = true;
 538         }
 539
 540 Finish:
 541         return ret;
 542 }
 543
 544 static void ext4_xattr_try_free_block(struct ext4_xattr_ref *xattr_ref)
 545 {
 546         ext4_fsblk_t xattr_block;
 547         xattr_block = ext4_inode_get_file_acl(xattr_ref->inode_ref->inode,
 548                                               &xattr_ref->fs->sb);
 549         ext4_inode_set_file_acl(xattr_ref->inode_ref->inode, &xattr_ref->fs->sb,
 550                                 0);
 551         ext4_block_set(xattr_ref->fs->bdev, &xattr_ref->block);
 552         ext4_balloc_free_block(xattr_ref->inode_ref, xattr_block);
 553         xattr_ref->inode_ref->dirty = true;
 554         xattr_ref->block_loaded = false;
 555 }
 556
 557 static void ext4_xattr_set_block_header(struct ext4_xattr_ref *xattr_ref)
 558 {
 559         struct ext4_xattr_header *block_header = NULL;
 560         block_header = EXT4_XATTR_BHDR(&xattr_ref->block);
 561
 562         memset(block_header, 0, sizeof(struct ext4_xattr_header));
 563         block_header->h_magic = EXT4_XATTR_MAGIC;
 564         block_header->h_refcount = to_le32(1);
 565         block_header->h_blocks = to_le32(1);
 566 }
 567
 568 static void
 569 ext4_xattr_set_inode_entry(struct ext4_xattr_item *item,
 570                            struct ext4_xattr_ibody_header *ibody_header,
 571                            struct ext4_xattr_entry *entry, void *ibody_data_ptr)
 572 {
 573         entry->e_name_len = to_le32(item->name_len);
 574         entry->e_name_index = item->name_index;
 575         entry->e_value_offs =
 576             (char *)ibody_data_ptr - (char *)EXT4_XATTR_IFIRST(ibody_header);
 577         entry->e_value_block = 0;
 578         entry->e_value_size = item->data_size;
 579 }
 580
 581 static void ext4_xattr_set_block_entry(struct ext4_xattr_item *item,
 582                                        struct ext4_xattr_header *block_header,
 583                                        struct ext4_xattr_entry *block_entry,
 584                                        void *block_data_ptr)
 585 {
 586         block_entry->e_name_len = to_le32(item->name_len);
 587         block_entry->e_name_index = item->name_index;
 588         block_entry->e_value_offs =
 589             (char *)block_data_ptr - (char *)block_header;
 590         block_entry->e_value_block = 0;
 591         block_entry->e_value_size = item->data_size;
 592 }
 593
 594 static int ext4_xattr_write_to_disk(struct ext4_xattr_ref *xattr_ref)
 595 {
 596         int ret = EOK;
 597         bool block_modified = false;
 598         void *ibody_data = NULL;
 599         void *block_data = NULL;
 600         struct ext4_xattr_item *item, *save_item;
 601         size_t inode_size_rem, block_size_rem;
 602         struct ext4_xattr_ibody_header *ibody_header = NULL;
 603         struct ext4_xattr_header *block_header = NULL;
 604         struct ext4_xattr_entry *entry = NULL;
 605         struct ext4_xattr_entry *block_entry = NULL;
 606
 607         inode_size_rem = ext4_xattr_inode_space(xattr_ref);
 608         block_size_rem = ext4_xattr_block_space(xattr_ref);
 609         if (inode_size_rem > sizeof(struct ext4_xattr_ibody_header)) {
 610                 ibody_header = EXT4_XATTR_IHDR(xattr_ref->inode_ref->inode);
 611                 entry = EXT4_XATTR_IFIRST(ibody_header);
 612         }
 613
 614         if (!xattr_ref->dirty)
 615                 goto Finish;
 616         /* If there are enough spaces in the ibody EA table.*/
 617         if (inode_size_rem > sizeof(struct ext4_xattr_ibody_header)) {
 618                 memset(ibody_header, 0, inode_size_rem);
 619                 ibody_header->h_magic = EXT4_XATTR_MAGIC;
 620                 ibody_data = (char *)ibody_header + inode_size_rem;
 621                 inode_size_rem -= sizeof(struct ext4_xattr_ibody_header);
 622
 623                 xattr_ref->inode_ref->dirty = true;
 624         }
 625         /* If we need an extra block to hold the EA entries*/
 626         if (xattr_ref->ea_size > inode_size_rem) {
 627                 if (!xattr_ref->block_loaded) {
 628                         ret = ext4_xattr_try_alloc_block(xattr_ref);
 629                         if (ret != EOK)
 630                                 goto Finish;
 631                 }
 632                 block_header = EXT4_XATTR_BHDR(&xattr_ref->block);
 633                 block_entry = EXT4_XATTR_BFIRST(&xattr_ref->block);
 634                 ext4_xattr_set_block_header(xattr_ref);
 635                 block_data = (char *)block_header + block_size_rem;
 636                 block_size_rem -= sizeof(struct ext4_xattr_header);
 637
 638                 xattr_ref->block.dirty = true;
 639         } else {
 640                 /* We don't need an extra block.*/
 641                 if (xattr_ref->block_loaded) {
 642                         block_header = EXT4_XATTR_BHDR(&xattr_ref->block);
 643                         block_header->h_refcount =
 644                             to_le32(to_le32(block_header->h_refcount) - 1);
 645                         if (!block_header->h_refcount) {
 646                                 ext4_xattr_try_free_block(xattr_ref);
 647                                 block_header = NULL;
 648                         } else {
 649                                 block_entry =
 650                                     EXT4_XATTR_BFIRST(&xattr_ref->block);
 651                                 block_data =
 652                                     (char *)block_header + block_size_rem;
 653                                 block_size_rem -=
 654                                     sizeof(struct ext4_xattr_header);
 655                                 ext4_inode_set_file_acl(
 656                                     xattr_ref->inode_ref->inode,
 657                                     &xattr_ref->fs->sb, 0);
 658
 659                                 xattr_ref->inode_ref->dirty = true;
 660                                 xattr_ref->block.dirty = true;
 661                         }
 662                 }
 663         }
 664         RB_FOREACH_SAFE(item, ext4_xattr_tree, &xattr_ref->root, save_item)
 665         {
 666                 if (EXT4_XATTR_SIZE(item->data_size) +
 667                         EXT4_XATTR_LEN(item->name_len) <=
 668                     inode_size_rem) {
 669                         ibody_data = (char *)ibody_data -
 670                                      EXT4_XATTR_SIZE(item->data_size);
 671                         ext4_xattr_set_inode_entry(item, ibody_header, entry,
 672                                                    ibody_data);
 673                         memcpy(EXT4_XATTR_NAME(entry), item->name,
 674                                item->name_len);
 675                         memcpy(ibody_data, item->data, item->data_size);
 676                         entry = EXT4_XATTR_NEXT(entry);
 677                         inode_size_rem -= EXT4_XATTR_SIZE(item->data_size) +
 678                                           EXT4_XATTR_LEN(item->name_len);
 679
 680                         xattr_ref->inode_ref->dirty = true;
 681                         continue;
 682                 }
 683                 if (EXT4_XATTR_SIZE(item->data_size) +
 684                         EXT4_XATTR_LEN(item->name_len) >
 685                     block_size_rem) {
 686                         ret = ENOSPC;
 687                         goto Finish;
 688                 }
 689                 block_data =
 690                     (char *)block_data - EXT4_XATTR_SIZE(item->data_size);
 691                 ext4_xattr_set_block_entry(item, block_header, block_entry,
 692                                            block_data);
 693                 memcpy(EXT4_XATTR_NAME(block_entry), item->name,
 694                        item->name_len);
 695                 memcpy(block_data, item->data, item->data_size);
 696                 block_entry = EXT4_XATTR_NEXT(block_entry);
 697                 block_size_rem -= EXT4_XATTR_SIZE(item->data_size) +
 698                                   EXT4_XATTR_LEN(item->name_len);
 699
 700                 block_modified = true;
 701         }
 702         xattr_ref->dirty = false;
 703         if (block_modified) {
 704                 ext4_xattr_rehash(block_header,
 705                                   EXT4_XATTR_BFIRST(&xattr_ref->block));
 706                 ext4_xattr_set_block_checksum(xattr_ref->inode_ref,
 707                                               xattr_ref->block.lb_id,
 708                                               block_header);
 709                 xattr_ref->block.dirty = true;
 710         }
 711
 712 Finish:
 713         return ret;
 714 }
 715
 716 void ext4_fs_xattr_iterate(struct ext4_xattr_ref *ref,
 717                            int (*iter)(struct ext4_xattr_ref *ref,
 718                                      struct ext4_xattr_item *item))
 719 {
 720         struct ext4_xattr_item *item;
 721         if (!ref->iter_from)
 722                 ref->iter_from = RB_MIN(ext4_xattr_tree, &ref->root);
 723
 724         RB_FOREACH_FROM(item, ext4_xattr_tree, ref->iter_from)
 725         {
 726                 int ret = EXT4_XATTR_ITERATE_CONT;
 727                 if (iter)
 728                         iter(ref, item);
 729
 730                 if (ret != EXT4_XATTR_ITERATE_CONT) {
 731                         if (ret == EXT4_XATTR_ITERATE_STOP)
 732                                 ref->iter_from = NULL;
 733
 734                         break;
 735                 }
 736         }
 737 }
 738
 739 void ext4_fs_xattr_iterate_reset(struct ext4_xattr_ref *ref)
 740 {
 741         ref->iter_from = NULL;
 742 }
 743
 744 int ext4_fs_set_xattr(struct ext4_xattr_ref *ref, uint8_t name_index,
 745                       const char *name, size_t name_len, const void *data,
 746                       size_t data_size, bool replace)
 747 {
 748         int ret = EOK;
 749         struct ext4_xattr_item *item =
 750             ext4_xattr_lookup_item(ref, name_index, name, name_len);
 751         if (replace) {
 752                 if (!item) {
 753                         ret = ENODATA;
 754                         goto Finish;
 755                 }
 756                 if (item->data_size != data_size)
 757                         ret = ext4_xattr_resize_item(ref, item, data_size);
 758
 759                 if (ret != EOK) {
 760                         goto Finish;
 761                 }
 762                 memcpy(item->data, data, data_size);
 763         } else {
 764                 if (item) {
 765                         ret = EEXIST;
 766                         goto Finish;
 767                 }
 768                 item = ext4_xattr_insert_item(ref, name_index, name, name_len,
 769                                               data, data_size);
 770                 if (!item)
 771                         ret = ENOMEM;
 772         }
 773 Finish:
 774         return ret;
 775 }
 776
 777 int ext4_fs_remove_xattr(struct ext4_xattr_ref *ref, uint8_t name_index,
 778                          const char *name, size_t name_len)
 779 {
 780         return ext4_xattr_remove_item(ref, name_index, name, name_len);
 781 }
 782
 783 int ext4_fs_get_xattr(struct ext4_xattr_ref *ref, uint8_t name_index,
 784                       const char *name, size_t name_len, void *buf, size_t buf_size,
 785                       size_t *data_size)
 786 {
 787         int ret = EOK;
 788         size_t item_size = 0;
 789         struct ext4_xattr_item *item =
 790             ext4_xattr_lookup_item(ref, name_index, name, name_len);
 791
 792         if (!item) {
 793                 ret = ENODATA;
 794                 goto Finish;
 795         }
 796         item_size = item->data_size;
 797         if (buf_size > item_size)
 798                 buf_size = item_size;
 799
 800         if (buf)
 801                 memcpy(buf, item->data, buf_size);
 802
 803 Finish:
 804         if (data_size)
 805                 *data_size = item_size;
 806
 807         return ret;
 808 }
 809
 810 int ext4_fs_get_xattr_ref(struct ext4_fs *fs, struct ext4_inode_ref *inode_ref,
 811                           struct ext4_xattr_ref *ref)
 812 {
 813         int rc;
 814         ext4_fsblk_t xattr_block;
 815         xattr_block = ext4_inode_get_file_acl(inode_ref->inode, &fs->sb);
 816         RB_INIT(&ref->root);
 817         ref->ea_size = 0;
 818         ref->iter_from = NULL;
 819         if (xattr_block) {
 820                 rc = ext4_block_get(fs->bdev, &ref->block, xattr_block);
 821                 if (rc != EOK)
 822                         return EIO;
 823
 824                 ref->block_loaded = true;
 825         } else
 826                 ref->block_loaded = false;
 827
 828         ref->inode_ref = inode_ref;
 829         ref->fs = fs;
 830
 831         rc = ext4_xattr_fetch(ref);
 832         if (rc != EOK) {
 833                 ext4_xattr_purge_items(ref);
 834                 if (xattr_block)
 835                         ext4_block_set(fs->bdev, &inode_ref->block);
 836
 837                 ref->block_loaded = false;
 838                 return rc;
 839         }
 840         return EOK;
 841 }
 842
 843 void ext4_fs_put_xattr_ref(struct ext4_xattr_ref *ref)
 844 {
 845         ext4_xattr_write_to_disk(ref);
 846         if (ref->block_loaded) {
 847                 ext4_block_set(ref->fs->bdev, &ref->block);
 848                 ref->block_loaded = false;
 849         }
 850         ext4_xattr_purge_items(ref);
 851         ref->inode_ref = NULL;
 852         ref->fs = NULL;
 853 }
 854
 855 struct xattr_prefix {
 856         const char *prefix;
 857         uint8_t name_index;
 858 };
 859
 860 static const struct xattr_prefix prefix_tbl[] = {
 861     {"user.", EXT4_XATTR_INDEX_USER},
 862     {"system.", EXT4_XATTR_INDEX_SYSTEM},
 863     {"system.posix_acl_access", EXT4_XATTR_INDEX_POSIX_ACL_ACCESS},
 864     {"system.posix_acl_default", EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT},
 865     {NULL, 0},
 866 };
 867
 868 const char *ext4_extract_xattr_name(const char *full_name, size_t full_name_len,
 869                               uint8_t *name_index, size_t *name_len)
 870 {
 871         int i;
 872         ext4_assert(name_index);
 873         if (!full_name_len) {
 874                 if (name_len)
 875                         *name_len = 0;
 876
 877                 return NULL;
 878         }
 879
 880         for (i = 0; prefix_tbl[i].prefix; i++) {
 881                 size_t prefix_len = strlen(prefix_tbl[i].prefix);
 882                 if (full_name_len >= prefix_len &&
 883                     !memcmp(full_name, prefix_tbl[i].prefix, prefix_len)) {
 884                         *name_index = prefix_tbl[i].name_index;
 885                         if (name_len)
 886                                 *name_len = full_name_len - prefix_len;
 887
 888                         return full_name + prefix_len;
 889                 }
 890         }
 891         if (name_len)
 892                 *name_len = 0;
 893
 894         return NULL;
 895 }
 896
 897 const char *ext4_get_xattr_name_prefix(uint8_t name_index, size_t *ret_prefix_len)
 898 {
 899         int i;
 900
 901         for (i = 0; prefix_tbl[i].prefix; i++) {
 902                 size_t prefix_len = strlen(prefix_tbl[i].prefix);
 903                 if (prefix_tbl[i].name_index == name_index) {
 904                         if (ret_prefix_len)
 905                                 *ret_prefix_len = prefix_len;
 906
 907                         return prefix_tbl[i].prefix;
 908                 }
 909         }
 910         if (ret_prefix_len)
 911                 *ret_prefix_len = 0;
 912
 913         return NULL;
 914 }
 915
 916 /**
 917  * @}
 918  */