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, const 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                                       const 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         char *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 = ((char *)first_entry + to_le16(entry->e_value_offs));
 215                 if (ret + EXT4_XATTR_SIZE(to_le32(entry->e_value_size)) -
 216                         (char *)xattr_ref->inode_ref->inode > inode_size)
 217                         ret = NULL;
 218
 219                 return ret;
 220
 221         }
 222         int32_t block_size = ext4_sb_get_block_size(&xattr_ref->fs->sb);
 223         ret = ((char *)xattr_ref->block.data + to_le16(entry->e_value_offs));
 224         if (ret + EXT4_XATTR_SIZE(to_le32(entry->e_value_size)) -
 225                         (char *)xattr_ref->block.data > block_size)
 226                 ret = NULL;
 227         return ret;
 228 }
 229
 230 static int ext4_xattr_block_fetch(struct ext4_xattr_ref *xattr_ref)
 231 {
 232         int ret = EOK;
 233         size_t size_rem;
 234         void *data;
 235         struct ext4_xattr_entry *entry = NULL;
 236
 237         ext4_assert(xattr_ref->block.data);
 238         entry = EXT4_XATTR_BFIRST(&xattr_ref->block);
 239
 240         size_rem = ext4_sb_get_block_size(&xattr_ref->fs->sb);
 241         for (; size_rem > 0 && !EXT4_XATTR_IS_LAST_ENTRY(entry);
 242              entry = EXT4_XATTR_NEXT(entry),
 243              size_rem -= EXT4_XATTR_LEN(entry->e_name_len)) {
 244                 struct ext4_xattr_item *item;
 245                 char *e_name = EXT4_XATTR_NAME(entry);
 246
 247                 data = ext4_xattr_entry_data(xattr_ref, entry, false);
 248                 if (!data) {
 249                         ret = EIO;
 250                         goto Finish;
 251                 }
 252
 253                 item = ext4_xattr_item_alloc(entry->e_name_index, e_name,
 254                                              (size_t)entry->e_name_len);
 255                 if (!item) {
 256                         ret = ENOMEM;
 257                         goto Finish;
 258                 }
 259                 if (ext4_xattr_item_alloc_data(
 260                         item, data, to_le32(entry->e_value_size)) != EOK) {
 261                         ext4_xattr_item_free(item);
 262                         ret = ENOMEM;
 263                         goto Finish;
 264                 }
 265                 RB_INSERT(ext4_xattr_tree, &xattr_ref->root, item);
 266                 xattr_ref->ea_size += EXT4_XATTR_SIZE(item->data_size) +
 267                                       EXT4_XATTR_LEN(item->name_len);
 268         }
 269
 270 Finish:
 271         return ret;
 272 }
 273
 274 static int ext4_xattr_inode_fetch(struct ext4_xattr_ref *xattr_ref)
 275 {
 276         void *data;
 277         size_t size_rem;
 278         int ret = EOK;
 279         struct ext4_xattr_ibody_header *header = NULL;
 280         struct ext4_xattr_entry *entry = NULL;
 281         uint16_t inode_size = ext4_get16(&xattr_ref->fs->sb, inode_size);
 282
 283         header = EXT4_XATTR_IHDR(xattr_ref->inode_ref->inode);
 284         entry = EXT4_XATTR_IFIRST(header);
 285
 286         size_rem = inode_size - EXT4_GOOD_OLD_INODE_SIZE -
 287                    xattr_ref->inode_ref->inode->extra_isize;
 288         for (; size_rem > 0 && !EXT4_XATTR_IS_LAST_ENTRY(entry);
 289              entry = EXT4_XATTR_NEXT(entry),
 290              size_rem -= EXT4_XATTR_LEN(entry->e_name_len)) {
 291                 struct ext4_xattr_item *item;
 292                 char *e_name = EXT4_XATTR_NAME(entry);
 293
 294                 data = ext4_xattr_entry_data(xattr_ref, entry, true);
 295                 if (!data) {
 296                         ret = EIO;
 297                         goto Finish;
 298                 }
 299
 300                 item = ext4_xattr_item_alloc(entry->e_name_index, e_name,
 301                                              (size_t)entry->e_name_len);
 302                 if (!item) {
 303                         ret = ENOMEM;
 304                         goto Finish;
 305                 }
 306                 if (ext4_xattr_item_alloc_data(
 307                         item, data, to_le32(entry->e_value_size)) != EOK) {
 308                         ext4_xattr_item_free(item);
 309                         ret = ENOMEM;
 310                         goto Finish;
 311                 }
 312                 RB_INSERT(ext4_xattr_tree, &xattr_ref->root, item);
 313                 xattr_ref->ea_size += EXT4_XATTR_SIZE(item->data_size) +
 314                                       EXT4_XATTR_LEN(item->name_len);
 315         }
 316
 317 Finish:
 318         return ret;
 319 }
 320
 321 static size_t ext4_xattr_inode_space(struct ext4_xattr_ref *xattr_ref)
 322 {
 323         uint16_t inode_size = ext4_get16(&xattr_ref->fs->sb, inode_size);
 324         uint16_t size_rem = inode_size - EXT4_GOOD_OLD_INODE_SIZE -
 325                             xattr_ref->inode_ref->inode->extra_isize;
 326         return size_rem;
 327 }
 328
 329 static size_t ext4_xattr_block_space(struct ext4_xattr_ref *xattr_ref)
 330 {
 331         return ext4_sb_get_block_size(&xattr_ref->fs->sb);
 332 }
 333
 334 static int ext4_xattr_fetch(struct ext4_xattr_ref *xattr_ref)
 335 {
 336         int ret = EOK;
 337         uint16_t inode_size = ext4_get16(&xattr_ref->fs->sb, inode_size);
 338         if (inode_size > EXT4_GOOD_OLD_INODE_SIZE) {
 339                 ret = ext4_xattr_inode_fetch(xattr_ref);
 340                 if (ret != EOK)
 341                         return ret;
 342         }
 343
 344         if (xattr_ref->block_loaded)
 345                 ret = ext4_xattr_block_fetch(xattr_ref);
 346
 347         xattr_ref->dirty = false;
 348         return ret;
 349 }
 350
 351 static struct ext4_xattr_item *
 352 ext4_xattr_lookup_item(struct ext4_xattr_ref *xattr_ref, uint8_t name_index,
 353                        const char *name, size_t name_len)
 354 {
 355         struct ext4_xattr_item tmp = {
 356                 .name_index = name_index,
 357                 .name = (char *)name, /*RB_FIND - won't touch this string*/
 358                 .name_len = name_len,
 359         };
 360
 361         return RB_FIND(ext4_xattr_tree, &xattr_ref->root, &tmp);
 362 }
 363
 364 static struct ext4_xattr_item *
 365 ext4_xattr_insert_item(struct ext4_xattr_ref *xattr_ref, uint8_t name_index,
 366                        const char *name, size_t name_len, const void *data,
 367                        size_t data_size)
 368 {
 369         struct ext4_xattr_item *item;
 370         item = ext4_xattr_item_alloc(name_index, name, name_len);
 371         if (!item)
 372                 return NULL;
 373
 374         if ((xattr_ref->ea_size + EXT4_XATTR_SIZE(data_size) +
 375                 EXT4_XATTR_LEN(item->name_len)
 376                         >
 377             ext4_xattr_inode_space(xattr_ref) -
 378                 sizeof(struct ext4_xattr_ibody_header))
 379                 &&
 380             (xattr_ref->ea_size + EXT4_XATTR_SIZE(data_size) +
 381                 EXT4_XATTR_LEN(item->name_len) >
 382             ext4_xattr_block_space(xattr_ref) -
 383                 sizeof(struct ext4_xattr_header))) {
 384                 ext4_xattr_item_free(item);
 385
 386                 return NULL;
 387         }
 388         if (ext4_xattr_item_alloc_data(item, data, data_size) != EOK) {
 389                 ext4_xattr_item_free(item);
 390                 return NULL;
 391         }
 392         RB_INSERT(ext4_xattr_tree, &xattr_ref->root, item);
 393         xattr_ref->ea_size +=
 394             EXT4_XATTR_SIZE(item->data_size) + EXT4_XATTR_LEN(item->name_len);
 395         xattr_ref->dirty = true;
 396         return item;
 397 }
 398
 399 static int ext4_xattr_remove_item(struct ext4_xattr_ref *xattr_ref,
 400                                   uint8_t name_index, const char *name,
 401                                   size_t name_len)
 402 {
 403         int ret = ENOENT;
 404         struct ext4_xattr_item *item =
 405             ext4_xattr_lookup_item(xattr_ref, name_index, name, name_len);
 406         if (item) {
 407                 if (item == xattr_ref->iter_from)
 408                         xattr_ref->iter_from =
 409                             RB_NEXT(ext4_xattr_tree, &xattr_ref->root, item);
 410
 411                 RB_REMOVE(ext4_xattr_tree, &xattr_ref->root, item);
 412                 ext4_xattr_item_free(item);
 413                 xattr_ref->ea_size -= EXT4_XATTR_SIZE(item->data_size) +
 414                                       EXT4_XATTR_LEN(item->name_len);
 415                 xattr_ref->dirty = true;
 416                 ret = EOK;
 417         }
 418         return ret;
 419 }
 420
 421 static int ext4_xattr_resize_item(struct ext4_xattr_ref *xattr_ref,
 422                                   struct ext4_xattr_item *item,
 423                                   size_t new_data_size)
 424 {
 425         int ret = EOK;
 426         if (xattr_ref->ea_size - EXT4_XATTR_SIZE(item->data_size) +
 427                 EXT4_XATTR_SIZE(new_data_size) >
 428             ext4_xattr_inode_space(xattr_ref) +
 429                 ext4_xattr_block_space(xattr_ref)) {
 430
 431                 return ENOSPC;
 432         }
 433         ret = ext4_xattr_item_resize_data(item, new_data_size);
 434         if (ret != EOK) {
 435                 return ret;
 436         }
 437         xattr_ref->ea_size -=
 438             EXT4_XATTR_SIZE(item->data_size) + EXT4_XATTR_SIZE(new_data_size);
 439         xattr_ref->dirty = true;
 440         return ret;
 441 }
 442
 443 static void ext4_xattr_purge_items(struct ext4_xattr_ref *xattr_ref)
 444 {
 445         struct ext4_xattr_item *item, *save_item;
 446         RB_FOREACH_SAFE(item, ext4_xattr_tree, &xattr_ref->root, save_item)
 447         {
 448                 RB_REMOVE(ext4_xattr_tree, &xattr_ref->root, item);
 449                 ext4_xattr_item_free(item);
 450         }
 451         xattr_ref->ea_size = 0;
 452 }
 453
 454 static int ext4_xattr_try_alloc_block(struct ext4_xattr_ref *xattr_ref)
 455 {
 456         int ret = EOK;
 457
 458         uint64_t xattr_block = 0;
 459         xattr_block = ext4_inode_get_file_acl(xattr_ref->inode_ref->inode,
 460                                               &xattr_ref->fs->sb);
 461         if (!xattr_block) {
 462                 ret = ext4_balloc_alloc_block(xattr_ref->inode_ref,
 463                                               (uint32_t *)&xattr_block);
 464                 if (ret != EOK)
 465                         goto Finish;
 466
 467                 ret = ext4_block_get(xattr_ref->fs->bdev, &xattr_ref->block,
 468                                      xattr_block);
 469                 if (ret != EOK) {
 470                         ext4_balloc_free_block(xattr_ref->inode_ref,
 471                                                xattr_block);
 472                         goto Finish;
 473                 }
 474
 475                 ext4_inode_set_file_acl(xattr_ref->inode_ref->inode,
 476                                         &xattr_ref->fs->sb, xattr_block);
 477                 xattr_ref->inode_ref->dirty = true;
 478                 xattr_ref->block_loaded = true;
 479         }
 480
 481 Finish:
 482         return ret;
 483 }
 484
 485 static void ext4_xattr_try_free_block(struct ext4_xattr_ref *xattr_ref)
 486 {
 487         uint64_t xattr_block;
 488         xattr_block = ext4_inode_get_file_acl(xattr_ref->inode_ref->inode,
 489                                               &xattr_ref->fs->sb);
 490         ext4_inode_set_file_acl(xattr_ref->inode_ref->inode, &xattr_ref->fs->sb,
 491                                 0);
 492         ext4_block_set(xattr_ref->fs->bdev, &xattr_ref->block);
 493         ext4_balloc_free_block(xattr_ref->inode_ref, xattr_block);
 494         xattr_ref->inode_ref->dirty = true;
 495         xattr_ref->block_loaded = false;
 496 }
 497
 498 static void ext4_xattr_set_block_header(struct ext4_xattr_ref *xattr_ref)
 499 {
 500         struct ext4_xattr_header *block_header = NULL;
 501         block_header = EXT4_XATTR_BHDR(&xattr_ref->block);
 502
 503         memset(block_header, 0, sizeof(struct ext4_xattr_header));
 504         block_header->h_magic = EXT4_XATTR_MAGIC;
 505         block_header->h_refcount = to_le32(1);
 506         block_header->h_blocks = to_le32(1);
 507 }
 508
 509 static void
 510 ext4_xattr_set_inode_entry(struct ext4_xattr_item *item,
 511                            struct ext4_xattr_ibody_header *ibody_header,
 512                            struct ext4_xattr_entry *entry, void *ibody_data_ptr)
 513 {
 514         entry->e_name_len = to_le32(item->name_len);
 515         entry->e_name_index = item->name_index;
 516         entry->e_value_offs =
 517             (char *)ibody_data_ptr - (char *)EXT4_XATTR_IFIRST(ibody_header);
 518         entry->e_value_block = 0;
 519         entry->e_value_size = item->data_size;
 520 }
 521
 522 static void ext4_xattr_set_block_entry(struct ext4_xattr_item *item,
 523                                        struct ext4_xattr_header *block_header,
 524                                        struct ext4_xattr_entry *block_entry,
 525                                        void *block_data_ptr)
 526 {
 527         block_entry->e_name_len = to_le32(item->name_len);
 528         block_entry->e_name_index = item->name_index;
 529         block_entry->e_value_offs =
 530             (char *)block_data_ptr - (char *)block_header;
 531         block_entry->e_value_block = 0;
 532         block_entry->e_value_size = item->data_size;
 533 }
 534
 535 static int ext4_xattr_write_to_disk(struct ext4_xattr_ref *xattr_ref)
 536 {
 537         int ret = EOK;
 538         bool block_modified = false;
 539         void *ibody_data = NULL;
 540         void *block_data = NULL;
 541         struct ext4_xattr_item *item, *save_item;
 542         size_t inode_size_rem, block_size_rem;
 543         struct ext4_xattr_ibody_header *ibody_header = NULL;
 544         struct ext4_xattr_header *block_header = NULL;
 545         struct ext4_xattr_entry *entry = NULL;
 546         struct ext4_xattr_entry *block_entry = NULL;
 547
 548         inode_size_rem = ext4_xattr_inode_space(xattr_ref);
 549         block_size_rem = ext4_xattr_block_space(xattr_ref);
 550         if (inode_size_rem > sizeof(struct ext4_xattr_ibody_header)) {
 551                 ibody_header = EXT4_XATTR_IHDR(xattr_ref->inode_ref->inode);
 552                 entry = EXT4_XATTR_IFIRST(ibody_header);
 553         }
 554
 555         if (!xattr_ref->dirty)
 556                 goto Finish;
 557         /* If there are enough spaces in the ibody EA table.*/
 558         if (inode_size_rem > sizeof(struct ext4_xattr_ibody_header)) {
 559                 memset(ibody_header, 0, inode_size_rem);
 560                 ibody_header->h_magic = EXT4_XATTR_MAGIC;
 561                 ibody_data = (char *)ibody_header + inode_size_rem;
 562                 inode_size_rem -= sizeof(struct ext4_xattr_ibody_header);
 563
 564                 xattr_ref->inode_ref->dirty = true;
 565         }
 566         /* If we need an extra block to hold the EA entries*/
 567         if (xattr_ref->ea_size > inode_size_rem) {
 568                 if (!xattr_ref->block_loaded) {
 569                         ret = ext4_xattr_try_alloc_block(xattr_ref);
 570                         if (ret != EOK)
 571                                 goto Finish;
 572                 }
 573                 block_header = EXT4_XATTR_BHDR(&xattr_ref->block);
 574                 block_entry = EXT4_XATTR_BFIRST(&xattr_ref->block);
 575                 ext4_xattr_set_block_header(xattr_ref);
 576                 block_data = (char *)block_header + block_size_rem;
 577                 block_size_rem -= sizeof(struct ext4_xattr_header);
 578
 579                 xattr_ref->block.dirty = true;
 580         } else {
 581                 /* We don't need an extra block.*/
 582                 if (xattr_ref->block_loaded) {
 583                         block_header = EXT4_XATTR_BHDR(&xattr_ref->block);
 584                         block_header->h_refcount =
 585                             to_le32(to_le32(block_header->h_refcount) - 1);
 586                         if (!block_header->h_refcount) {
 587                                 ext4_xattr_try_free_block(xattr_ref);
 588                                 block_header = NULL;
 589                         } else {
 590                                 block_entry =
 591                                     EXT4_XATTR_BFIRST(&xattr_ref->block);
 592                                 block_data =
 593                                     (char *)block_header + block_size_rem;
 594                                 block_size_rem -=
 595                                     sizeof(struct ext4_xattr_header);
 596                                 ext4_inode_set_file_acl(
 597                                     xattr_ref->inode_ref->inode,
 598                                     &xattr_ref->fs->sb, 0);
 599
 600                                 xattr_ref->inode_ref->dirty = true;
 601                                 xattr_ref->block.dirty = true;
 602                         }
 603                 }
 604         }
 605         RB_FOREACH_SAFE(item, ext4_xattr_tree, &xattr_ref->root, save_item)
 606         {
 607                 if (EXT4_XATTR_SIZE(item->data_size) +
 608                         EXT4_XATTR_LEN(item->name_len) <=
 609                     inode_size_rem) {
 610                         ibody_data = (char *)ibody_data -
 611                                      EXT4_XATTR_SIZE(item->data_size);
 612                         ext4_xattr_set_inode_entry(item, ibody_header, entry,
 613                                                    ibody_data);
 614                         memcpy(EXT4_XATTR_NAME(entry), item->name,
 615                                item->name_len);
 616                         memcpy(ibody_data, item->data, item->data_size);
 617                         entry = EXT4_XATTR_NEXT(entry);
 618                         inode_size_rem -= EXT4_XATTR_SIZE(item->data_size) +
 619                                           EXT4_XATTR_LEN(item->name_len);
 620
 621                         xattr_ref->inode_ref->dirty = true;
 622                         continue;
 623                 }
 624                 if (EXT4_XATTR_SIZE(item->data_size) +
 625                         EXT4_XATTR_LEN(item->name_len) >
 626                     block_size_rem) {
 627                         ret = ENOSPC;
 628                         goto Finish;
 629                 }
 630                 block_data =
 631                     (char *)block_data - EXT4_XATTR_SIZE(item->data_size);
 632                 ext4_xattr_set_block_entry(item, block_header, block_entry,
 633                                            block_data);
 634                 memcpy(EXT4_XATTR_NAME(block_entry), item->name,
 635                        item->name_len);
 636                 memcpy(block_data, item->data, item->data_size);
 637                 block_entry = EXT4_XATTR_NEXT(block_entry);
 638                 block_size_rem -= EXT4_XATTR_SIZE(item->data_size) +
 639                                   EXT4_XATTR_LEN(item->name_len);
 640
 641                 block_modified = true;
 642         }
 643         xattr_ref->dirty = false;
 644         if (block_modified) {
 645                 ext4_xattr_rehash(block_header,
 646                                   EXT4_XATTR_BFIRST(&xattr_ref->block));
 647                 xattr_ref->block.dirty = true;
 648         }
 649
 650 Finish:
 651         return ret;
 652 }
 653
 654 void ext4_fs_xattr_iterate(struct ext4_xattr_ref *ref,
 655                            int (*iter)(struct ext4_xattr_ref *ref,
 656                                      struct ext4_xattr_item *item))
 657 {
 658         struct ext4_xattr_item *item;
 659         if (!ref->iter_from)
 660                 ref->iter_from = RB_MIN(ext4_xattr_tree, &ref->root);
 661
 662         RB_FOREACH_FROM(item, ext4_xattr_tree, ref->iter_from)
 663         {
 664                 int ret = EXT4_XATTR_ITERATE_CONT;
 665                 if (iter)
 666                         iter(ref, item);
 667
 668                 if (ret != EXT4_XATTR_ITERATE_CONT) {
 669                         if (ret == EXT4_XATTR_ITERATE_STOP)
 670                                 ref->iter_from = NULL;
 671
 672                         break;
 673                 }
 674         }
 675 }
 676
 677 void ext4_fs_xattr_iterate_reset(struct ext4_xattr_ref *ref)
 678 {
 679         ref->iter_from = NULL;
 680 }
 681
 682 int ext4_fs_set_xattr(struct ext4_xattr_ref *ref, uint8_t name_index,
 683                       const char *name, size_t name_len, const void *data,
 684                       size_t data_size, bool replace)
 685 {
 686         int ret = EOK;
 687         struct ext4_xattr_item *item =
 688             ext4_xattr_lookup_item(ref, name_index, name, name_len);
 689         if (replace) {
 690                 if (!item) {
 691                         ret = ENOATTR;
 692                         goto Finish;
 693                 }
 694                 if (item->data_size != data_size)
 695                         ret = ext4_xattr_resize_item(ref, item, data_size);
 696
 697                 if (ret != EOK) {
 698                         goto Finish;
 699                 }
 700                 memcpy(item->data, data, data_size);
 701         } else {
 702                 if (item) {
 703                         ret = EEXIST;
 704                         goto Finish;
 705                 }
 706                 item = ext4_xattr_insert_item(ref, name_index, name, name_len,
 707                                               data, data_size);
 708                 if (!item)
 709                         ret = ENOMEM;
 710         }
 711 Finish:
 712         return ret;
 713 }
 714
 715 int ext4_fs_remove_xattr(struct ext4_xattr_ref *ref, uint8_t name_index,
 716                          const char *name, size_t name_len)
 717 {
 718         return ext4_xattr_remove_item(ref, name_index, name, name_len);
 719 }
 720
 721 int ext4_fs_get_xattr(struct ext4_xattr_ref *ref, uint8_t name_index,
 722                       const char *name, size_t name_len, void *buf, size_t buf_size,
 723                       size_t *data_size)
 724 {
 725         int ret = EOK;
 726         size_t item_size = 0;
 727         struct ext4_xattr_item *item =
 728             ext4_xattr_lookup_item(ref, name_index, name, name_len);
 729
 730         if (!item) {
 731                 ret = ENOATTR;
 732                 goto Finish;
 733         }
 734         item_size = item->data_size;
 735         if (buf_size > item_size)
 736                 buf_size = item_size;
 737
 738         if (buf)
 739                 memcpy(buf, item->data, buf_size);
 740
 741 Finish:
 742         if (data_size)
 743                 *data_size = item_size;
 744
 745         return ret;
 746 }
 747
 748 int ext4_fs_get_xattr_ref(struct ext4_fs *fs, struct ext4_inode_ref *inode_ref,
 749                           struct ext4_xattr_ref *ref)
 750 {
 751         int rc;
 752         uint64_t xattr_block;
 753         xattr_block = ext4_inode_get_file_acl(inode_ref->inode, &fs->sb);
 754         RB_INIT(&ref->root);
 755         ref->ea_size = 0;
 756         ref->iter_from = NULL;
 757         if (xattr_block) {
 758                 rc = ext4_block_get(fs->bdev, &ref->block, xattr_block);
 759                 if (rc != EOK)
 760                         return EIO;
 761
 762                 ref->block_loaded = true;
 763         } else
 764                 ref->block_loaded = false;
 765
 766         ref->inode_ref = inode_ref;
 767         ref->fs = fs;
 768
 769         rc = ext4_xattr_fetch(ref);
 770         if (rc != EOK) {
 771                 ext4_xattr_purge_items(ref);
 772                 if (xattr_block)
 773                         ext4_block_set(fs->bdev, &inode_ref->block);
 774
 775                 ref->block_loaded = false;
 776                 return rc;
 777         }
 778         return EOK;
 779 }
 780
 781 void ext4_fs_put_xattr_ref(struct ext4_xattr_ref *ref)
 782 {
 783         ext4_xattr_write_to_disk(ref);
 784         if (ref->block_loaded) {
 785                 ext4_block_set(ref->fs->bdev, &ref->block);
 786                 ref->block_loaded = false;
 787         }
 788         ext4_xattr_purge_items(ref);
 789         ref->inode_ref = NULL;
 790         ref->fs = NULL;
 791 }
 792
 793 struct xattr_prefix {
 794         const char *prefix;
 795         uint8_t name_index;
 796 };
 797
 798 static const struct xattr_prefix prefix_tbl[] = {
 799     {"user.", EXT4_XATTR_INDEX_USER},
 800     {"system.", EXT4_XATTR_INDEX_SYSTEM},
 801     {"system.posix_acl_access", EXT4_XATTR_INDEX_POSIX_ACL_ACCESS},
 802     {"system.posix_acl_default", EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT},
 803     {NULL, 0},
 804 };
 805
 806 const char *ext4_extract_xattr_name(const char *full_name, size_t full_name_len,
 807                               uint8_t *name_index, size_t *name_len)
 808 {
 809         int i;
 810         ext4_assert(name_index);
 811         if (!full_name_len) {
 812                 if (name_len)
 813                         *name_len = 0;
 814
 815                 return NULL;
 816         }
 817
 818         for (i = 0; prefix_tbl[i].prefix; i++) {
 819                 size_t prefix_len = strlen(prefix_tbl[i].prefix);
 820                 if (full_name_len >= prefix_len &&
 821                     !memcmp(full_name, prefix_tbl[i].prefix, prefix_len)) {
 822                         *name_index = prefix_tbl[i].name_index;
 823                         if (name_len)
 824                                 *name_len = full_name_len - prefix_len;
 825
 826                         return full_name + prefix_len;
 827                 }
 828         }
 829         if (name_len)
 830                 *name_len = 0;
 831
 832         return NULL;
 833 }
 834
 835 const char *ext4_get_xattr_name_prefix(uint8_t name_index, size_t *ret_prefix_len)
 836 {
 837         int i;
 838
 839         for (i = 0; prefix_tbl[i].prefix; i++) {
 840                 size_t prefix_len = strlen(prefix_tbl[i].prefix);
 841                 if (prefix_tbl[i].name_index == name_index) {
 842                         if (ret_prefix_len)
 843                                 *ret_prefix_len = prefix_len;
 844
 845                         return prefix_tbl[i].prefix;
 846                 }
 847         }
 848         if (ret_prefix_len)
 849                 *ret_prefix_len = 0;
 850
 851         return NULL;
 852 }
 853
 854 /**
 855  * @}
 856  */