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             xattr_ref->ea_size -
 439             EXT4_XATTR_SIZE(item->data_size) +
 440             EXT4_XATTR_SIZE(new_data_size);
 441         xattr_ref->dirty = true;
 442         return ret;
 443 }
 444
 445 static void ext4_xattr_purge_items(struct ext4_xattr_ref *xattr_ref)
 446 {
 447         struct ext4_xattr_item *item, *save_item;
 448         RB_FOREACH_SAFE(item, ext4_xattr_tree, &xattr_ref->root, save_item)
 449         {
 450                 RB_REMOVE(ext4_xattr_tree, &xattr_ref->root, item);
 451                 ext4_xattr_item_free(item);
 452         }
 453         xattr_ref->ea_size = 0;
 454 }
 455
 456 static int ext4_xattr_try_alloc_block(struct ext4_xattr_ref *xattr_ref)
 457 {
 458         int ret = EOK;
 459
 460         uint64_t xattr_block = 0;
 461         xattr_block = ext4_inode_get_file_acl(xattr_ref->inode_ref->inode,
 462                                               &xattr_ref->fs->sb);
 463         if (!xattr_block) {
 464                 ret = ext4_balloc_alloc_block(xattr_ref->inode_ref,
 465                                               (uint32_t *)&xattr_block);
 466                 if (ret != EOK)
 467                         goto Finish;
 468
 469                 ret = ext4_block_get(xattr_ref->fs->bdev, &xattr_ref->block,
 470                                      xattr_block);
 471                 if (ret != EOK) {
 472                         ext4_balloc_free_block(xattr_ref->inode_ref,
 473                                                xattr_block);
 474                         goto Finish;
 475                 }
 476
 477                 ext4_inode_set_file_acl(xattr_ref->inode_ref->inode,
 478                                         &xattr_ref->fs->sb, xattr_block);
 479                 xattr_ref->inode_ref->dirty = true;
 480                 xattr_ref->block_loaded = true;
 481         }
 482
 483 Finish:
 484         return ret;
 485 }
 486
 487 static void ext4_xattr_try_free_block(struct ext4_xattr_ref *xattr_ref)
 488 {
 489         uint64_t xattr_block;
 490         xattr_block = ext4_inode_get_file_acl(xattr_ref->inode_ref->inode,
 491                                               &xattr_ref->fs->sb);
 492         ext4_inode_set_file_acl(xattr_ref->inode_ref->inode, &xattr_ref->fs->sb,
 493                                 0);
 494         ext4_block_set(xattr_ref->fs->bdev, &xattr_ref->block);
 495         ext4_balloc_free_block(xattr_ref->inode_ref, xattr_block);
 496         xattr_ref->inode_ref->dirty = true;
 497         xattr_ref->block_loaded = false;
 498 }
 499
 500 static void ext4_xattr_set_block_header(struct ext4_xattr_ref *xattr_ref)
 501 {
 502         struct ext4_xattr_header *block_header = NULL;
 503         block_header = EXT4_XATTR_BHDR(&xattr_ref->block);
 504
 505         memset(block_header, 0, sizeof(struct ext4_xattr_header));
 506         block_header->h_magic = EXT4_XATTR_MAGIC;
 507         block_header->h_refcount = to_le32(1);
 508         block_header->h_blocks = to_le32(1);
 509 }
 510
 511 static void
 512 ext4_xattr_set_inode_entry(struct ext4_xattr_item *item,
 513                            struct ext4_xattr_ibody_header *ibody_header,
 514                            struct ext4_xattr_entry *entry, void *ibody_data_ptr)
 515 {
 516         entry->e_name_len = to_le32(item->name_len);
 517         entry->e_name_index = item->name_index;
 518         entry->e_value_offs =
 519             (char *)ibody_data_ptr - (char *)EXT4_XATTR_IFIRST(ibody_header);
 520         entry->e_value_block = 0;
 521         entry->e_value_size = item->data_size;
 522 }
 523
 524 static void ext4_xattr_set_block_entry(struct ext4_xattr_item *item,
 525                                        struct ext4_xattr_header *block_header,
 526                                        struct ext4_xattr_entry *block_entry,
 527                                        void *block_data_ptr)
 528 {
 529         block_entry->e_name_len = to_le32(item->name_len);
 530         block_entry->e_name_index = item->name_index;
 531         block_entry->e_value_offs =
 532             (char *)block_data_ptr - (char *)block_header;
 533         block_entry->e_value_block = 0;
 534         block_entry->e_value_size = item->data_size;
 535 }
 536
 537 static int ext4_xattr_write_to_disk(struct ext4_xattr_ref *xattr_ref)
 538 {
 539         int ret = EOK;
 540         bool block_modified = false;
 541         void *ibody_data = NULL;
 542         void *block_data = NULL;
 543         struct ext4_xattr_item *item, *save_item;
 544         size_t inode_size_rem, block_size_rem;
 545         struct ext4_xattr_ibody_header *ibody_header = NULL;
 546         struct ext4_xattr_header *block_header = NULL;
 547         struct ext4_xattr_entry *entry = NULL;
 548         struct ext4_xattr_entry *block_entry = NULL;
 549
 550         inode_size_rem = ext4_xattr_inode_space(xattr_ref);
 551         block_size_rem = ext4_xattr_block_space(xattr_ref);
 552         if (inode_size_rem > sizeof(struct ext4_xattr_ibody_header)) {
 553                 ibody_header = EXT4_XATTR_IHDR(xattr_ref->inode_ref->inode);
 554                 entry = EXT4_XATTR_IFIRST(ibody_header);
 555         }
 556
 557         if (!xattr_ref->dirty)
 558                 goto Finish;
 559         /* If there are enough spaces in the ibody EA table.*/
 560         if (inode_size_rem > sizeof(struct ext4_xattr_ibody_header)) {
 561                 memset(ibody_header, 0, inode_size_rem);
 562                 ibody_header->h_magic = EXT4_XATTR_MAGIC;
 563                 ibody_data = (char *)ibody_header + inode_size_rem;
 564                 inode_size_rem -= sizeof(struct ext4_xattr_ibody_header);
 565
 566                 xattr_ref->inode_ref->dirty = true;
 567         }
 568         /* If we need an extra block to hold the EA entries*/
 569         if (xattr_ref->ea_size > inode_size_rem) {
 570                 if (!xattr_ref->block_loaded) {
 571                         ret = ext4_xattr_try_alloc_block(xattr_ref);
 572                         if (ret != EOK)
 573                                 goto Finish;
 574                 }
 575                 block_header = EXT4_XATTR_BHDR(&xattr_ref->block);
 576                 block_entry = EXT4_XATTR_BFIRST(&xattr_ref->block);
 577                 ext4_xattr_set_block_header(xattr_ref);
 578                 block_data = (char *)block_header + block_size_rem;
 579                 block_size_rem -= sizeof(struct ext4_xattr_header);
 580
 581                 xattr_ref->block.dirty = true;
 582         } else {
 583                 /* We don't need an extra block.*/
 584                 if (xattr_ref->block_loaded) {
 585                         block_header = EXT4_XATTR_BHDR(&xattr_ref->block);
 586                         block_header->h_refcount =
 587                             to_le32(to_le32(block_header->h_refcount) - 1);
 588                         if (!block_header->h_refcount) {
 589                                 ext4_xattr_try_free_block(xattr_ref);
 590                                 block_header = NULL;
 591                         } else {
 592                                 block_entry =
 593                                     EXT4_XATTR_BFIRST(&xattr_ref->block);
 594                                 block_data =
 595                                     (char *)block_header + block_size_rem;
 596                                 block_size_rem -=
 597                                     sizeof(struct ext4_xattr_header);
 598                                 ext4_inode_set_file_acl(
 599                                     xattr_ref->inode_ref->inode,
 600                                     &xattr_ref->fs->sb, 0);
 601
 602                                 xattr_ref->inode_ref->dirty = true;
 603                                 xattr_ref->block.dirty = true;
 604                         }
 605                 }
 606         }
 607         RB_FOREACH_SAFE(item, ext4_xattr_tree, &xattr_ref->root, save_item)
 608         {
 609                 if (EXT4_XATTR_SIZE(item->data_size) +
 610                         EXT4_XATTR_LEN(item->name_len) <=
 611                     inode_size_rem) {
 612                         ibody_data = (char *)ibody_data -
 613                                      EXT4_XATTR_SIZE(item->data_size);
 614                         ext4_xattr_set_inode_entry(item, ibody_header, entry,
 615                                                    ibody_data);
 616                         memcpy(EXT4_XATTR_NAME(entry), item->name,
 617                                item->name_len);
 618                         memcpy(ibody_data, item->data, item->data_size);
 619                         entry = EXT4_XATTR_NEXT(entry);
 620                         inode_size_rem -= EXT4_XATTR_SIZE(item->data_size) +
 621                                           EXT4_XATTR_LEN(item->name_len);
 622
 623                         xattr_ref->inode_ref->dirty = true;
 624                         continue;
 625                 }
 626                 if (EXT4_XATTR_SIZE(item->data_size) +
 627                         EXT4_XATTR_LEN(item->name_len) >
 628                     block_size_rem) {
 629                         ret = ENOSPC;
 630                         goto Finish;
 631                 }
 632                 block_data =
 633                     (char *)block_data - EXT4_XATTR_SIZE(item->data_size);
 634                 ext4_xattr_set_block_entry(item, block_header, block_entry,
 635                                            block_data);
 636                 memcpy(EXT4_XATTR_NAME(block_entry), item->name,
 637                        item->name_len);
 638                 memcpy(block_data, item->data, item->data_size);
 639                 block_entry = EXT4_XATTR_NEXT(block_entry);
 640                 block_size_rem -= EXT4_XATTR_SIZE(item->data_size) +
 641                                   EXT4_XATTR_LEN(item->name_len);
 642
 643                 block_modified = true;
 644         }
 645         xattr_ref->dirty = false;
 646         if (block_modified) {
 647                 ext4_xattr_rehash(block_header,
 648                                   EXT4_XATTR_BFIRST(&xattr_ref->block));
 649                 xattr_ref->block.dirty = true;
 650         }
 651
 652 Finish:
 653         return ret;
 654 }
 655
 656 void ext4_fs_xattr_iterate(struct ext4_xattr_ref *ref,
 657                            int (*iter)(struct ext4_xattr_ref *ref,
 658                                      struct ext4_xattr_item *item))
 659 {
 660         struct ext4_xattr_item *item;
 661         if (!ref->iter_from)
 662                 ref->iter_from = RB_MIN(ext4_xattr_tree, &ref->root);
 663
 664         RB_FOREACH_FROM(item, ext4_xattr_tree, ref->iter_from)
 665         {
 666                 int ret = EXT4_XATTR_ITERATE_CONT;
 667                 if (iter)
 668                         iter(ref, item);
 669
 670                 if (ret != EXT4_XATTR_ITERATE_CONT) {
 671                         if (ret == EXT4_XATTR_ITERATE_STOP)
 672                                 ref->iter_from = NULL;
 673
 674                         break;
 675                 }
 676         }
 677 }
 678
 679 void ext4_fs_xattr_iterate_reset(struct ext4_xattr_ref *ref)
 680 {
 681         ref->iter_from = NULL;
 682 }
 683
 684 int ext4_fs_set_xattr(struct ext4_xattr_ref *ref, uint8_t name_index,
 685                       const char *name, size_t name_len, const void *data,
 686                       size_t data_size, bool replace)
 687 {
 688         int ret = EOK;
 689         struct ext4_xattr_item *item =
 690             ext4_xattr_lookup_item(ref, name_index, name, name_len);
 691         if (replace) {
 692                 if (!item) {
 693                         ret = ENOATTR;
 694                         goto Finish;
 695                 }
 696                 if (item->data_size != data_size)
 697                         ret = ext4_xattr_resize_item(ref, item, data_size);
 698
 699                 if (ret != EOK) {
 700                         goto Finish;
 701                 }
 702                 memcpy(item->data, data, data_size);
 703         } else {
 704                 if (item) {
 705                         ret = EEXIST;
 706                         goto Finish;
 707                 }
 708                 item = ext4_xattr_insert_item(ref, name_index, name, name_len,
 709                                               data, data_size);
 710                 if (!item)
 711                         ret = ENOMEM;
 712         }
 713 Finish:
 714         return ret;
 715 }
 716
 717 int ext4_fs_remove_xattr(struct ext4_xattr_ref *ref, uint8_t name_index,
 718                          const char *name, size_t name_len)
 719 {
 720         return ext4_xattr_remove_item(ref, name_index, name, name_len);
 721 }
 722
 723 int ext4_fs_get_xattr(struct ext4_xattr_ref *ref, uint8_t name_index,
 724                       const char *name, size_t name_len, void *buf, size_t buf_size,
 725                       size_t *data_size)
 726 {
 727         int ret = EOK;
 728         size_t item_size = 0;
 729         struct ext4_xattr_item *item =
 730             ext4_xattr_lookup_item(ref, name_index, name, name_len);
 731
 732         if (!item) {
 733                 ret = ENOATTR;
 734                 goto Finish;
 735         }
 736         item_size = item->data_size;
 737         if (buf_size > item_size)
 738                 buf_size = item_size;
 739
 740         if (buf)
 741                 memcpy(buf, item->data, buf_size);
 742
 743 Finish:
 744         if (data_size)
 745                 *data_size = item_size;
 746
 747         return ret;
 748 }
 749
 750 int ext4_fs_get_xattr_ref(struct ext4_fs *fs, struct ext4_inode_ref *inode_ref,
 751                           struct ext4_xattr_ref *ref)
 752 {
 753         int rc;
 754         uint64_t xattr_block;
 755         xattr_block = ext4_inode_get_file_acl(inode_ref->inode, &fs->sb);
 756         RB_INIT(&ref->root);
 757         ref->ea_size = 0;
 758         ref->iter_from = NULL;
 759         if (xattr_block) {
 760                 rc = ext4_block_get(fs->bdev, &ref->block, xattr_block);
 761                 if (rc != EOK)
 762                         return EIO;
 763
 764                 ref->block_loaded = true;
 765         } else
 766                 ref->block_loaded = false;
 767
 768         ref->inode_ref = inode_ref;
 769         ref->fs = fs;
 770
 771         rc = ext4_xattr_fetch(ref);
 772         if (rc != EOK) {
 773                 ext4_xattr_purge_items(ref);
 774                 if (xattr_block)
 775                         ext4_block_set(fs->bdev, &inode_ref->block);
 776
 777                 ref->block_loaded = false;
 778                 return rc;
 779         }
 780         return EOK;
 781 }
 782
 783 void ext4_fs_put_xattr_ref(struct ext4_xattr_ref *ref)
 784 {
 785         ext4_xattr_write_to_disk(ref);
 786         if (ref->block_loaded) {
 787                 ext4_block_set(ref->fs->bdev, &ref->block);
 788                 ref->block_loaded = false;
 789         }
 790         ext4_xattr_purge_items(ref);
 791         ref->inode_ref = NULL;
 792         ref->fs = NULL;
 793 }
 794
 795 struct xattr_prefix {
 796         const char *prefix;
 797         uint8_t name_index;
 798 };
 799
 800 static const struct xattr_prefix prefix_tbl[] = {
 801     {"user.", EXT4_XATTR_INDEX_USER},
 802     {"system.", EXT4_XATTR_INDEX_SYSTEM},
 803     {"system.posix_acl_access", EXT4_XATTR_INDEX_POSIX_ACL_ACCESS},
 804     {"system.posix_acl_default", EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT},
 805     {NULL, 0},
 806 };
 807
 808 const char *ext4_extract_xattr_name(const char *full_name, size_t full_name_len,
 809                               uint8_t *name_index, size_t *name_len)
 810 {
 811         int i;
 812         ext4_assert(name_index);
 813         if (!full_name_len) {
 814                 if (name_len)
 815                         *name_len = 0;
 816
 817                 return NULL;
 818         }
 819
 820         for (i = 0; prefix_tbl[i].prefix; i++) {
 821                 size_t prefix_len = strlen(prefix_tbl[i].prefix);
 822                 if (full_name_len >= prefix_len &&
 823                     !memcmp(full_name, prefix_tbl[i].prefix, prefix_len)) {
 824                         *name_index = prefix_tbl[i].name_index;
 825                         if (name_len)
 826                                 *name_len = full_name_len - prefix_len;
 827
 828                         return full_name + prefix_len;
 829                 }
 830         }
 831         if (name_len)
 832                 *name_len = 0;
 833
 834         return NULL;
 835 }
 836
 837 const char *ext4_get_xattr_name_prefix(uint8_t name_index, size_t *ret_prefix_len)
 838 {
 839         int i;
 840
 841         for (i = 0; prefix_tbl[i].prefix; i++) {
 842                 size_t prefix_len = strlen(prefix_tbl[i].prefix);
 843                 if (prefix_tbl[i].name_index == name_index) {
 844                         if (ret_prefix_len)
 845                                 *ret_prefix_len = prefix_len;
 846
 847                         return prefix_tbl[i].prefix;
 848                 }
 849         }
 850         if (ret_prefix_len)
 851                 *ret_prefix_len = 0;
 852
 853         return NULL;
 854 }
 855
 856 /**
 857  * @}
 858  */