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_debug.h"
  44 #include "ext4_block_group.h"
  45 #include "ext4_balloc.h"
  46 #include "ext4_inode.h"
  47 #include "ext4_extent.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 int ext4_xattr_item_cmp(struct ext4_xattr_item *a,
 116                                struct ext4_xattr_item *b)
 117 {
 118         int result;
 119         result = a->name_index - b->name_index;
 120         if (result)
 121                 return result;
 122
 123         result = a->name_len - b->name_len;
 124         if (result)
 125                 return result;
 126
 127         return memcmp(a->name, b->name, a->name_len);
 128 }
 129
 130 RB_GENERATE_INTERNAL(ext4_xattr_tree, ext4_xattr_item, node,
 131                      ext4_xattr_item_cmp, static inline)
 132
 133 static struct ext4_xattr_item *
 134 ext4_xattr_item_alloc(uint8_t name_index, char *name, size_t name_len)
 135 {
 136         struct ext4_xattr_item *item;
 137         item = malloc(sizeof(struct ext4_xattr_item) + name_len);
 138         if (!item)
 139                 return NULL;
 140
 141         item->name_index = name_index;
 142         item->name = (char *)(item + 1);
 143         item->name_len = name_len;
 144         item->data = NULL;
 145         item->data_size = 0;
 146
 147         memset(&item->node, 0, sizeof(item->node));
 148         memcpy(item->name, name, name_len);
 149
 150         return item;
 151 }
 152
 153 static int ext4_xattr_item_alloc_data(struct ext4_xattr_item *item,
 154                                       void *orig_data, size_t data_size)
 155 {
 156         void *data = NULL;
 157         ext4_assert(!item->data);
 158         data = malloc(data_size);
 159         if (!data)
 160                 return ENOMEM;
 161
 162         if (orig_data)
 163                 memcpy(data, orig_data, data_size);
 164
 165         item->data = data;
 166         item->data_size = data_size;
 167         return EOK;
 168 }
 169
 170 static void ext4_xattr_item_free_data(struct ext4_xattr_item *item)
 171 {
 172         ext4_assert(item->data);
 173         free(item->data);
 174         item->data = NULL;
 175         item->data_size = 0;
 176 }
 177
 178 static int ext4_xattr_item_resize_data(struct ext4_xattr_item *item,
 179                                        size_t new_data_size)
 180 {
 181         if (new_data_size != item->data_size) {
 182                 void *new_data;
 183                 new_data = realloc(item->data, new_data_size);
 184                 if (!new_data)
 185                         return ENOMEM;
 186
 187                 item->data = new_data;
 188                 item->data_size = new_data_size;
 189         }
 190         return EOK;
 191 }
 192
 193 static void ext4_xattr_item_free(struct ext4_xattr_item *item)
 194 {
 195         if (item->data)
 196                 ext4_xattr_item_free_data(item);
 197
 198         free(item);
 199 }
 200
 201 static void *ext4_xattr_entry_data(struct ext4_xattr_ref *xattr_ref,
 202                                    struct ext4_xattr_entry *entry,
 203                                    bool in_inode)
 204 {
 205         void *ret;
 206         if (in_inode) {
 207                 struct ext4_xattr_ibody_header *header;
 208                 struct ext4_xattr_entry *first_entry;
 209                 int16_t inode_size =
 210                     ext4_get16(&xattr_ref->fs->sb, inode_size);
 211                 header = EXT4_XATTR_IHDR(xattr_ref->inode_ref->inode);
 212                 first_entry = EXT4_XATTR_IFIRST(header);
 213
 214                 ret = (void *)((char *)first_entry +
 215                                to_le16(entry->e_value_offs));
 216                 if ((char *)ret +
 217                         EXT4_XATTR_SIZE(to_le32(entry->e_value_size)) -
 218                         (char *)xattr_ref->inode_ref->inode >
 219                     inode_size)
 220                         ret = NULL;
 221
 222         } else {
 223                 int32_t block_size = ext4_sb_get_block_size(&xattr_ref->fs->sb);
 224                 ret = (void *)((char *)xattr_ref->block.data +
 225                                to_le16(entry->e_value_offs));
 226                 if ((char *)ret +
 227                         EXT4_XATTR_SIZE(to_le32(entry->e_value_size)) -
 228                         (char *)xattr_ref->block.data >
 229                     block_size)
 230                         ret = NULL;
 231         }
 232         return ret;
 233 }
 234
 235 static int ext4_xattr_block_fetch(struct ext4_xattr_ref *xattr_ref)
 236 {
 237         int ret = EOK;
 238         size_t size_rem;
 239         void *data;
 240         struct ext4_xattr_entry *entry = NULL;
 241
 242         ext4_assert(xattr_ref->block.data);
 243         entry = EXT4_XATTR_BFIRST(&xattr_ref->block);
 244
 245         size_rem = ext4_sb_get_block_size(&xattr_ref->fs->sb);
 246         for (; size_rem > 0 && !EXT4_XATTR_IS_LAST_ENTRY(entry);
 247              entry = EXT4_XATTR_NEXT(entry),
 248              size_rem -= EXT4_XATTR_LEN(entry->e_name_len)) {
 249                 struct ext4_xattr_item *item;
 250                 char *e_name = EXT4_XATTR_NAME(entry);
 251
 252                 data = ext4_xattr_entry_data(xattr_ref, entry, false);
 253                 if (!data) {
 254                         ret = EIO;
 255                         goto Finish;
 256                 }
 257
 258                 item = ext4_xattr_item_alloc(entry->e_name_index, e_name,
 259                                              (size_t)entry->e_name_len);
 260                 if (!item) {
 261                         ret = ENOMEM;
 262                         goto Finish;
 263                 }
 264                 if (ext4_xattr_item_alloc_data(
 265                         item, data, to_le32(entry->e_value_size)) != EOK) {
 266                         ext4_xattr_item_free(item);
 267                         ret = ENOMEM;
 268                         goto Finish;
 269                 }
 270                 RB_INSERT(ext4_xattr_tree, &xattr_ref->root, item);
 271                 xattr_ref->ea_size += EXT4_XATTR_SIZE(item->data_size) +
 272                                       EXT4_XATTR_LEN(item->name_len);
 273         }
 274
 275 Finish:
 276         return ret;
 277 }
 278
 279 static int ext4_xattr_inode_fetch(struct ext4_xattr_ref *xattr_ref)
 280 {
 281         void *data;
 282         size_t size_rem;
 283         int ret = EOK;
 284         struct ext4_xattr_ibody_header *header = NULL;
 285         struct ext4_xattr_entry *entry = NULL;
 286         uint16_t inode_size = ext4_get16(&xattr_ref->fs->sb, inode_size);
 287
 288         header = EXT4_XATTR_IHDR(xattr_ref->inode_ref->inode);
 289         entry = EXT4_XATTR_IFIRST(header);
 290
 291         size_rem = inode_size - EXT4_GOOD_OLD_INODE_SIZE -
 292                    xattr_ref->inode_ref->inode->extra_isize;
 293         for (; size_rem > 0 && !EXT4_XATTR_IS_LAST_ENTRY(entry);
 294              entry = EXT4_XATTR_NEXT(entry),
 295              size_rem -= EXT4_XATTR_LEN(entry->e_name_len)) {
 296                 struct ext4_xattr_item *item;
 297                 char *e_name = EXT4_XATTR_NAME(entry);
 298
 299                 data = ext4_xattr_entry_data(xattr_ref, entry, true);
 300                 if (!data) {
 301                         ret = EIO;
 302                         goto Finish;
 303                 }
 304
 305                 item = ext4_xattr_item_alloc(entry->e_name_index, e_name,
 306                                              (size_t)entry->e_name_len);
 307                 if (!item) {
 308                         ret = ENOMEM;
 309                         goto Finish;
 310                 }
 311                 if (ext4_xattr_item_alloc_data(
 312                         item, data, to_le32(entry->e_value_size)) != EOK) {
 313                         ext4_xattr_item_free(item);
 314                         ret = ENOMEM;
 315                         goto Finish;
 316                 }
 317                 RB_INSERT(ext4_xattr_tree, &xattr_ref->root, item);
 318                 xattr_ref->ea_size += EXT4_XATTR_SIZE(item->data_size) +
 319                                       EXT4_XATTR_LEN(item->name_len);
 320         }
 321
 322 Finish:
 323         return ret;
 324 }
 325
 326 static size_t ext4_xattr_inode_space(struct ext4_xattr_ref *xattr_ref)
 327 {
 328         uint16_t inode_size = ext4_get16(&xattr_ref->fs->sb, inode_size);
 329         uint16_t size_rem = inode_size - EXT4_GOOD_OLD_INODE_SIZE -
 330                             xattr_ref->inode_ref->inode->extra_isize;
 331         return size_rem;
 332 }
 333
 334 static size_t ext4_xattr_block_space(struct ext4_xattr_ref *xattr_ref)
 335 {
 336         return ext4_sb_get_block_size(&xattr_ref->fs->sb);
 337 }
 338
 339 static int ext4_xattr_fetch(struct ext4_xattr_ref *xattr_ref)
 340 {
 341         int ret = EOK;
 342         uint16_t inode_size = ext4_get16(&xattr_ref->fs->sb, inode_size);
 343         if (inode_size > EXT4_GOOD_OLD_INODE_SIZE) {
 344                 ret = ext4_xattr_inode_fetch(xattr_ref);
 345                 if (ret != EOK)
 346                         return ret;
 347         }
 348
 349         if (xattr_ref->block_loaded)
 350                 ret = ext4_xattr_block_fetch(xattr_ref);
 351
 352         xattr_ref->dirty = false;
 353         return ret;
 354 }
 355
 356 static struct ext4_xattr_item *
 357 ext4_xattr_lookup_item(struct ext4_xattr_ref *xattr_ref, uint8_t name_index,
 358                        char *name, size_t name_len)
 359 {
 360         struct ext4_xattr_item tmp, *ret;
 361         tmp.name_index = name_index;
 362         tmp.name = name;
 363         tmp.name_len = name_len;
 364         ret = RB_FIND(ext4_xattr_tree, &xattr_ref->root, &tmp);
 365         return ret;
 366 }
 367
 368 static struct ext4_xattr_item *
 369 ext4_xattr_insert_item(struct ext4_xattr_ref *xattr_ref, uint8_t name_index,
 370                        char *name, size_t name_len, void *data,
 371                        size_t data_size)
 372 {
 373         struct ext4_xattr_item *item;
 374         item = ext4_xattr_item_alloc(name_index, name, name_len);
 375         if (!item)
 376                 return NULL;
 377
 378         if (xattr_ref->ea_size + EXT4_XATTR_SIZE(item->data_size) +
 379                 EXT4_XATTR_LEN(item->name_len) >
 380             ext4_xattr_inode_space(xattr_ref) +
 381                 ext4_xattr_block_space(xattr_ref)) {
 382                 ext4_xattr_item_free(item);
 383                 return NULL;
 384         }
 385         if (ext4_xattr_item_alloc_data(item, data, data_size) != EOK) {
 386                 ext4_xattr_item_free(item);
 387                 return NULL;
 388         }
 389         RB_INSERT(ext4_xattr_tree, &xattr_ref->root, item);
 390         xattr_ref->ea_size +=
 391             EXT4_XATTR_SIZE(item->data_size) + EXT4_XATTR_LEN(item->name_len);
 392         xattr_ref->dirty = true;
 393         return item;
 394 }
 395
 396 static int ext4_xattr_remove_item(struct ext4_xattr_ref *xattr_ref,
 397                                   uint8_t name_index, char *name,
 398                                   size_t name_len)
 399 {
 400         int ret = ENOENT;
 401         struct ext4_xattr_item *item =
 402             ext4_xattr_lookup_item(xattr_ref, name_index, name, name_len);
 403         if (item) {
 404                 if (item == xattr_ref->iter_from)
 405                         xattr_ref->iter_from =
 406                             RB_NEXT(ext4_xattr_tree, &xattr_ref->root, item);
 407
 408                 RB_REMOVE(ext4_xattr_tree, &xattr_ref->root, item);
 409                 ext4_xattr_item_free(item);
 410                 xattr_ref->ea_size -= EXT4_XATTR_SIZE(item->data_size) +
 411                                       EXT4_XATTR_LEN(item->name_len);
 412                 xattr_ref->dirty = true;
 413                 ret = EOK;
 414         }
 415         return ret;
 416 }
 417
 418 static int ext4_xattr_resize_item(struct ext4_xattr_ref *xattr_ref,
 419                                   struct ext4_xattr_item *item,
 420                                   size_t new_data_size)
 421 {
 422         int ret = EOK;
 423         if (xattr_ref->ea_size - EXT4_XATTR_SIZE(item->data_size) +
 424                 EXT4_XATTR_SIZE(new_data_size) >
 425             ext4_xattr_inode_space(xattr_ref) +
 426                 ext4_xattr_block_space(xattr_ref)) {
 427
 428                 return ENOSPC;
 429         }
 430         ret = ext4_xattr_item_resize_data(item, new_data_size);
 431         if (ret != EOK) {
 432                 return ret;
 433         }
 434         xattr_ref->ea_size -=
 435             EXT4_XATTR_SIZE(item->data_size) + EXT4_XATTR_SIZE(new_data_size);
 436         xattr_ref->dirty = true;
 437         return ret;
 438 }
 439
 440 static void ext4_xattr_purge_items(struct ext4_xattr_ref *xattr_ref)
 441 {
 442         struct ext4_xattr_item *item, *save_item;
 443         uint64_t xattr_block = ext4_inode_get_file_acl(
 444             xattr_ref->inode_ref->inode, &xattr_ref->fs->sb);
 445         RB_FOREACH_SAFE(item, ext4_xattr_tree, &xattr_ref->root, save_item)
 446         {
 447                 RB_REMOVE(ext4_xattr_tree, &xattr_ref->root, item);
 448                 ext4_xattr_item_free(item);
 449         }
 450         xattr_ref->ea_size = 0;
 451         if (xattr_block)
 452                 xattr_ref->ea_size += sizeof(struct ext4_xattr_header);
 453
 454         if (ext4_xattr_inode_space(xattr_ref) >
 455             sizeof(struct ext4_xattr_ibody_header))
 456                 xattr_ref->ea_size += sizeof(struct ext4_xattr_ibody_header);
 457 }
 458
 459 static int ext4_xattr_try_alloc_block(struct ext4_xattr_ref *xattr_ref)
 460 {
 461         int ret = EOK;
 462
 463         uint64_t xattr_block = 0;
 464         xattr_block = ext4_inode_get_file_acl(xattr_ref->inode_ref->inode,
 465                                               &xattr_ref->fs->sb);
 466         if (!xattr_block) {
 467                 ret = ext4_balloc_alloc_block(xattr_ref->inode_ref,
 468                                               (uint32_t *)&xattr_block);
 469                 if (ret != EOK)
 470                         goto Finish;
 471
 472                 ret = ext4_block_get(xattr_ref->fs->bdev, &xattr_ref->block,
 473                                      xattr_block);
 474                 if (ret != EOK) {
 475                         ext4_balloc_free_block(xattr_ref->inode_ref,
 476                                                xattr_block);
 477                         goto Finish;
 478                 }
 479
 480                 ext4_inode_set_file_acl(xattr_ref->inode_ref->inode,
 481                                         &xattr_ref->fs->sb, xattr_block);
 482                 xattr_ref->inode_ref->dirty = true;
 483                 xattr_ref->block_loaded = true;
 484                 xattr_ref->ea_size += sizeof(struct ext4_xattr_header);
 485         }
 486
 487 Finish:
 488         return ret;
 489 }
 490
 491 static void ext4_xattr_try_free_block(struct ext4_xattr_ref *xattr_ref)
 492 {
 493         uint64_t xattr_block;
 494         xattr_block = ext4_inode_get_file_acl(xattr_ref->inode_ref->inode,
 495                                               &xattr_ref->fs->sb);
 496         ext4_inode_set_file_acl(xattr_ref->inode_ref->inode, &xattr_ref->fs->sb,
 497                                 0);
 498         ext4_block_set(xattr_ref->fs->bdev, &xattr_ref->block);
 499         ext4_balloc_free_block(xattr_ref->inode_ref, xattr_block);
 500         xattr_ref->inode_ref->dirty = true;
 501         xattr_ref->block_loaded = false;
 502         xattr_ref->ea_size -= sizeof(struct ext4_xattr_header);
 503 }
 504
 505 static void ext4_xattr_set_block_header(struct ext4_xattr_ref *xattr_ref)
 506 {
 507         struct ext4_xattr_header *block_header = NULL;
 508         block_header = EXT4_XATTR_BHDR(&xattr_ref->block);
 509
 510         memset(block_header, 0, sizeof(struct ext4_xattr_header));
 511         block_header->h_magic = EXT4_XATTR_MAGIC;
 512         block_header->h_refcount = to_le32(1);
 513         block_header->h_blocks = to_le32(1);
 514 }
 515
 516 static void
 517 ext4_xattr_set_inode_entry(struct ext4_xattr_item *item,
 518                            struct ext4_xattr_ibody_header *ibody_header,
 519                            struct ext4_xattr_entry *entry, void *ibody_data_ptr)
 520 {
 521         entry->e_name_len = to_le32(item->name_len);
 522         entry->e_name_index = item->name_index;
 523         entry->e_value_offs =
 524             (char *)ibody_data_ptr - (char *)EXT4_XATTR_IFIRST(ibody_header);
 525         entry->e_value_block = 0;
 526         entry->e_value_size = item->data_size;
 527 }
 528
 529 static void ext4_xattr_set_block_entry(struct ext4_xattr_item *item,
 530                                        struct ext4_xattr_header *block_header,
 531                                        struct ext4_xattr_entry *block_entry,
 532                                        void *block_data_ptr)
 533 {
 534         block_entry->e_name_len = to_le32(item->name_len);
 535         block_entry->e_name_index = item->name_index;
 536         block_entry->e_value_offs =
 537             (char *)block_data_ptr - (char *)block_header;
 538         block_entry->e_value_block = 0;
 539         block_entry->e_value_size = item->data_size;
 540 }
 541
 542 static int ext4_xattr_write_to_disk(struct ext4_xattr_ref *xattr_ref)
 543 {
 544         int ret = EOK;
 545         bool block_modified = false;
 546         void *ibody_data = 0;
 547         void *block_data = 0;
 548         struct ext4_xattr_item *item, *save_item;
 549         size_t inode_size_rem, block_size_rem;
 550         struct ext4_xattr_ibody_header *ibody_header = NULL;
 551         struct ext4_xattr_header *block_header = NULL;
 552         struct ext4_xattr_entry *entry = NULL;
 553         struct ext4_xattr_entry *block_entry = NULL;
 554
 555         inode_size_rem = ext4_xattr_inode_space(xattr_ref);
 556         block_size_rem = ext4_xattr_block_space(xattr_ref);
 557         if (inode_size_rem > sizeof(struct ext4_xattr_ibody_header)) {
 558                 ibody_header = EXT4_XATTR_IHDR(xattr_ref->inode_ref->inode);
 559                 entry = EXT4_XATTR_IFIRST(ibody_header);
 560         }
 561
 562         if (!xattr_ref->dirty)
 563                 goto Finish;
 564         /* If there are enough spaces in the ibody EA table.*/
 565         if (inode_size_rem > sizeof(struct ext4_xattr_ibody_header)) {
 566                 memset(ibody_header, 0, inode_size_rem);
 567                 ibody_header->h_magic = EXT4_XATTR_MAGIC;
 568                 ibody_data = (char *)ibody_header + inode_size_rem;
 569                 inode_size_rem -= sizeof(struct ext4_xattr_ibody_header);
 570
 571                 xattr_ref->inode_ref->dirty = true;
 572         }
 573         /* If we need an extra block to hold the EA entries*/
 574         if (xattr_ref->ea_size > inode_size_rem) {
 575                 if (!xattr_ref->block_loaded) {
 576                         ret = ext4_xattr_try_alloc_block(xattr_ref);
 577                         if (ret != EOK)
 578                                 goto Finish;
 579                 }
 580                 block_header = EXT4_XATTR_BHDR(&xattr_ref->block);
 581                 block_entry = EXT4_XATTR_BFIRST(&xattr_ref->block);
 582                 ext4_xattr_set_block_header(xattr_ref);
 583                 block_data = (char *)block_header + block_size_rem;
 584                 block_size_rem -= sizeof(struct ext4_xattr_header);
 585
 586                 xattr_ref->block.dirty = true;
 587         } else {
 588                 /* We don't need an extra block.*/
 589                 if (xattr_ref->block_loaded) {
 590                         block_header = EXT4_XATTR_BHDR(&xattr_ref->block);
 591                         block_header->h_refcount =
 592                             to_le32(to_le32(block_header->h_refcount) - 1);
 593                         if (!block_header->h_refcount) {
 594                                 ext4_xattr_try_free_block(xattr_ref);
 595                                 block_header = NULL;
 596                         } else {
 597                                 block_entry =
 598                                     EXT4_XATTR_BFIRST(&xattr_ref->block);
 599                                 block_data =
 600                                     (char *)block_header + block_size_rem;
 601                                 block_size_rem -=
 602                                     sizeof(struct ext4_xattr_header);
 603                                 ext4_inode_set_file_acl(
 604                                     xattr_ref->inode_ref->inode,
 605                                     &xattr_ref->fs->sb, 0);
 606
 607                                 xattr_ref->inode_ref->dirty = true;
 608                                 xattr_ref->block.dirty = true;
 609                         }
 610                 }
 611         }
 612         RB_FOREACH_SAFE(item, ext4_xattr_tree, &xattr_ref->root, save_item)
 613         {
 614                 if (EXT4_XATTR_SIZE(item->data_size) +
 615                         EXT4_XATTR_LEN(item->name_len) <=
 616                     inode_size_rem) {
 617                         ibody_data = (char *)ibody_data -
 618                                      EXT4_XATTR_SIZE(item->data_size);
 619                         ext4_xattr_set_inode_entry(item, ibody_header, entry,
 620                                                    ibody_data);
 621                         memcpy(EXT4_XATTR_NAME(entry), item->name,
 622                                item->name_len);
 623                         memcpy(ibody_data, item->data, item->data_size);
 624                         entry = EXT4_XATTR_NEXT(entry);
 625                         inode_size_rem -= EXT4_XATTR_SIZE(item->data_size) +
 626                                           EXT4_XATTR_LEN(item->name_len);
 627
 628                         xattr_ref->inode_ref->dirty = true;
 629                         continue;
 630                 }
 631                 if (EXT4_XATTR_SIZE(item->data_size) +
 632                         EXT4_XATTR_LEN(item->name_len) >
 633                     block_size_rem) {
 634                         ret = ENOSPC;
 635                         goto Finish;
 636                 }
 637                 block_data =
 638                     (char *)block_data - EXT4_XATTR_SIZE(item->data_size);
 639                 ext4_xattr_set_block_entry(item, block_header, block_entry,
 640                                            block_data);
 641                 memcpy(EXT4_XATTR_NAME(block_entry), item->name,
 642                        item->name_len);
 643                 memcpy(block_data, item->data, item->data_size);
 644                 block_entry = EXT4_XATTR_NEXT(block_entry);
 645                 block_size_rem -= EXT4_XATTR_SIZE(item->data_size) +
 646                                   EXT4_XATTR_LEN(item->name_len);
 647
 648                 block_modified = true;
 649         }
 650         xattr_ref->dirty = false;
 651         if (block_modified) {
 652                 ext4_xattr_rehash(block_header,
 653                                   EXT4_XATTR_BFIRST(&xattr_ref->block));
 654                 xattr_ref->block.dirty = true;
 655         }
 656
 657 Finish:
 658         return ret;
 659 }
 660
 661 void ext4_fs_xattr_iterate(struct ext4_xattr_ref *ref,
 662                            int(iter)(struct ext4_xattr_ref *ref,
 663                                      struct ext4_xattr_item *item))
 664 {
 665         struct ext4_xattr_item *item;
 666         if (!ref->iter_from)
 667                 ref->iter_from = RB_MIN(ext4_xattr_tree, &ref->root);
 668
 669         RB_FOREACH_FROM(item, ext4_xattr_tree, ref->iter_from)
 670         {
 671                 int ret = EXT4_XATTR_ITERATE_CONT;
 672                 if (iter)
 673                         iter(ref, item);
 674
 675                 if (ret != EXT4_XATTR_ITERATE_CONT) {
 676                         if (ret == EXT4_XATTR_ITERATE_STOP)
 677                                 ref->iter_from = NULL;
 678
 679                         break;
 680                 }
 681         }
 682 }
 683
 684 void ext4_fs_xattr_iterate_reset(struct ext4_xattr_ref *ref)
 685 {
 686         ref->iter_from = NULL;
 687 }
 688
 689 int ext4_fs_set_xattr(struct ext4_xattr_ref *ref, uint8_t name_index,
 690                       char *name, size_t name_len, void *data, size_t data_size,
 691                       bool replace)
 692 {
 693         int ret = EOK;
 694         struct ext4_xattr_item *item =
 695             ext4_xattr_lookup_item(ref, name_index, name, name_len);
 696         if (replace) {
 697                 if (!item) {
 698                         ret = ENOATTR;
 699                         goto Finish;
 700                 }
 701                 if (item->data_size != data_size)
 702                         ret = ext4_xattr_resize_item(ref, item, data_size);
 703
 704                 if (ret != EOK) {
 705                         goto Finish;
 706                 }
 707                 memcpy(item->data, data, data_size);
 708         } else {
 709                 if (item) {
 710                         ret = EEXIST;
 711                         goto Finish;
 712                 }
 713                 item = ext4_xattr_insert_item(ref, name_index, name, name_len,
 714                                               data, data_size);
 715                 if (!item)
 716                         ret = ENOMEM;
 717         }
 718 Finish:
 719         return ret;
 720 }
 721
 722 int ext4_fs_remove_xattr(struct ext4_xattr_ref *ref, uint8_t name_index,
 723                          char *name, size_t name_len)
 724 {
 725         return ext4_xattr_remove_item(ref, name_index, name, name_len);
 726 }
 727
 728 int ext4_fs_get_xattr(struct ext4_xattr_ref *ref, uint8_t name_index,
 729                       char *name, size_t name_len, void *buf, size_t buf_size,
 730                       size_t *size_got)
 731 {
 732         int ret = EOK;
 733         size_t item_size = 0;
 734         struct ext4_xattr_item *item =
 735             ext4_xattr_lookup_item(ref, name_index, name, name_len);
 736
 737         if (!item) {
 738                 ret = ENOATTR;
 739                 goto Finish;
 740         }
 741         item_size = item->data_size;
 742         if (buf_size > item_size)
 743                 buf_size = item_size;
 744
 745         if (buf)
 746                 memcpy(buf, item->data, buf_size);
 747
 748 Finish:
 749         if (size_got)
 750                 *size_got = buf_size;
 751
 752         return ret;
 753 }
 754
 755 int ext4_fs_get_xattr_ref(struct ext4_fs *fs, struct ext4_inode_ref *inode_ref,
 756                           struct ext4_xattr_ref *ref)
 757 {
 758         int rc;
 759         uint64_t xattr_block;
 760         xattr_block = ext4_inode_get_file_acl(inode_ref->inode, &fs->sb);
 761         RB_INIT(&ref->root);
 762         ref->ea_size = 0;
 763         ref->iter_from = NULL;
 764         if (xattr_block) {
 765                 rc = ext4_block_get(fs->bdev, &ref->block, xattr_block);
 766                 if (rc != EOK)
 767                         return EIO;
 768
 769                 ref->ea_size += sizeof(struct ext4_xattr_header);
 770                 ref->block_loaded = true;
 771         } else
 772                 ref->block_loaded = false;
 773
 774         ref->inode_ref = inode_ref;
 775         ref->fs = fs;
 776
 777         if (ext4_xattr_inode_space(ref) >
 778             sizeof(struct ext4_xattr_ibody_header))
 779                 ref->ea_size += sizeof(struct ext4_xattr_ibody_header);
 780
 781         rc = ext4_xattr_fetch(ref);
 782         if (rc != EOK) {
 783                 ext4_xattr_purge_items(ref);
 784                 if (xattr_block)
 785                         ext4_block_set(fs->bdev, &inode_ref->block);
 786
 787                 ref->block_loaded = false;
 788                 return rc;
 789         }
 790         return EOK;
 791 }
 792
 793 void ext4_fs_put_xattr_ref(struct ext4_xattr_ref *ref)
 794 {
 795         ext4_xattr_write_to_disk(ref);
 796         if (ref->block_loaded) {
 797                 ext4_block_set(ref->fs->bdev, &ref->block);
 798                 ref->block_loaded = false;
 799         }
 800         ext4_xattr_purge_items(ref);
 801         ref->inode_ref = NULL;
 802         ref->fs = NULL;
 803 }
 804
 805 struct xattr_prefix {
 806         char *prefix;
 807         uint8_t name_index;
 808 };
 809
 810 static const struct xattr_prefix prefix_tbl[] = {
 811     {"user.", EXT4_XATTR_INDEX_USER},
 812     {"system.", EXT4_XATTR_INDEX_SYSTEM},
 813     {"system.posix_acl_access", EXT4_XATTR_INDEX_POSIX_ACL_ACCESS},
 814     {"system.posix_acl_default", EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT},
 815     {NULL, 0},
 816 };
 817
 818 char *ext4_extract_xattr_name(char *full_name, size_t full_name_len,
 819                               uint8_t *name_index, size_t *name_len)
 820 {
 821         int i;
 822         ext4_assert(name_index);
 823         if (!full_name_len)
 824                 return NULL;
 825
 826         for (i = 0; prefix_tbl[i].prefix; i++) {
 827                 size_t prefix_len = strlen(prefix_tbl[i].prefix);
 828                 if (full_name_len >= prefix_len &&
 829                     !memcmp(full_name, prefix_tbl[i].prefix, prefix_len)) {
 830                         *name_index = prefix_tbl[i].name_index;
 831                         if (name_len)
 832                                 *name_len = full_name_len - prefix_len;
 833
 834                         return full_name + prefix_len;
 835                 }
 836         }
 837         if (name_len)
 838                 *name_len = 0;
 839
 840         return NULL;
 841 }
 842
 843 /**
 844  * @}
 845  */