src/ext4_xattr.c

   1 /*
   2  * Copyright (c) 2015 Grzegorz Kostka (kostka.grzegorz@gmail.com)
   3  * Copyright (c) 2015 Kaho Ng (ngkaho1234@gmail.com)
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  *
   9  * - Redistributions of source code must retain the above copyright
  10  *   notice, this list of conditions and the following disclaimer.
  11  * - Redistributions in binary form must reproduce the above copyright
  12  *   notice, this list of conditions and the following disclaimer in the
  13  *   documentation and/or other materials provided with the distribution.
  14  * - The name of the author may not be used to endorse or promote products
  15  *   derived from this software without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  */
  28
  29 /** @addtogroup lwext4
  30  * @{
  31  */
  32 /**
  33  * @file  ext4_xattr.c
  34  * @brief Extended Attribute manipulation.
  35  */
  36
  37 #include "ext4_config.h"
  38 #include "ext4_types.h"
  39 #include "ext4_misc.h"
  40 #include "ext4_errno.h"
  41 #include "ext4_debug.h"
  42
  43 #include "ext4_fs.h"
  44 #include "ext4_trans.h"
  45 #include "ext4_xattr.h"
  46 #include "ext4_blockdev.h"
  47 #include "ext4_super.h"
  48 #include "ext4_crc32.h"
  49 #include "ext4_block_group.h"
  50 #include "ext4_balloc.h"
  51 #include "ext4_inode.h"
  52
  53 #include <string.h>
  54 #include <stdlib.h>
  55
  56 /**
  57  * @file  ext4_xattr.c
  58  * @brief Extended Attribute Manipulation
  59  */
  60
  61 #define NAME_HASH_SHIFT 5
  62 #define VALUE_HASH_SHIFT 16
  63
  64 static inline void ext4_xattr_compute_hash(struct ext4_xattr_header *header,
  65                                            struct ext4_xattr_entry *entry)
  66 {
  67         uint32_t hash = 0;
  68         char *name = EXT4_XATTR_NAME(entry);
  69         int n;
  70
  71         for (n = 0; n < entry->e_name_len; n++) {
  72                 hash = (hash << NAME_HASH_SHIFT) ^
  73                        (hash >> (8 * sizeof(hash) - NAME_HASH_SHIFT)) ^ *name++;
  74         }
  75
  76         if (entry->e_value_block == 0 && entry->e_value_size != 0) {
  77                 uint32_t *value =
  78                     (uint32_t *)((char *)header + to_le16(entry->e_value_offs));
  79                 for (n = (to_le32(entry->e_value_size) + EXT4_XATTR_ROUND) >>
  80                          EXT4_XATTR_PAD_BITS;
  81                      n; n--) {
  82                         hash = (hash << VALUE_HASH_SHIFT) ^
  83                                (hash >> (8 * sizeof(hash) - VALUE_HASH_SHIFT)) ^
  84                                to_le32(*value++);
  85                 }
  86         }
  87         entry->e_hash = to_le32(hash);
  88 }
  89
  90 #define BLOCK_HASH_SHIFT 16
  91
  92 /*
  93  * ext4_xattr_rehash()
  94  *
  95  * Re-compute the extended attribute hash value after an entry has changed.
  96  */
  97 static void ext4_xattr_rehash(struct ext4_xattr_header *header,
  98                               struct ext4_xattr_entry *entry)
  99 {
 100         struct ext4_xattr_entry *here;
 101         uint32_t hash = 0;
 102
 103         ext4_xattr_compute_hash(header, entry);
 104         here = EXT4_XATTR_ENTRY(header + 1);
 105         while (!EXT4_XATTR_IS_LAST_ENTRY(here)) {
 106                 if (!here->e_hash) {
 107                         /* Block is not shared if an entry's hash value == 0 */
 108                         hash = 0;
 109                         break;
 110                 }
 111                 hash = (hash << BLOCK_HASH_SHIFT) ^
 112                        (hash >> (8 * sizeof(hash) - BLOCK_HASH_SHIFT)) ^
 113                        to_le32(here->e_hash);
 114                 here = EXT4_XATTR_NEXT(here);
 115         }
 116         header->h_hash = to_le32(hash);
 117 }
 118
 119 #if CONFIG_META_CSUM_ENABLE
 120 static uint32_t
 121 ext4_xattr_block_checksum(struct ext4_inode_ref *inode_ref,
 122                           ext4_fsblk_t blocknr,
 123                           struct ext4_xattr_header *header)
 124 {
 125         uint32_t checksum = 0;
 126         uint64_t le64_blocknr = blocknr;
 127         struct ext4_sblock *sb = &inode_ref->fs->sb;
 128
 129         if (ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM)) {
 130                 uint32_t orig_checksum;
 131
 132                 /* Preparation: temporarily set bg checksum to 0 */
 133                 orig_checksum = header->h_checksum;
 134                 header->h_checksum = 0;
 135                 /* First calculate crc32 checksum against fs uuid */
 136                 checksum = ext4_crc32c(EXT4_CRC32_INIT, sb->uuid,
 137                                 sizeof(sb->uuid));
 138                 /* Then calculate crc32 checksum block number */
 139                 checksum = ext4_crc32c(checksum, &le64_blocknr,
 140                                      sizeof(le64_blocknr));
 141                 /* Finally calculate crc32 checksum against
 142                  * the entire xattr block */
 143                 checksum = ext4_crc32c(checksum, header,
 144                                    ext4_sb_get_block_size(sb));
 145                 header->h_checksum = orig_checksum;
 146         }
 147         return checksum;
 148 }
 149 #else
 150 #define ext4_xattr_block_checksum(...) 0
 151 #endif
 152
 153 static void
 154 ext4_xattr_set_block_checksum(struct ext4_inode_ref *inode_ref,
 155                               ext4_fsblk_t blocknr __unused,
 156                               struct ext4_xattr_header *header)
 157 {
 158         struct ext4_sblock *sb = &inode_ref->fs->sb;
 159         if (!ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM))
 160                 return;
 161
 162         header->h_checksum =
 163                 ext4_xattr_block_checksum(inode_ref, blocknr, header);
 164 }
 165
 166 static int ext4_xattr_item_cmp(struct ext4_xattr_item *a,
 167                                struct ext4_xattr_item *b)
 168 {
 169         int result;
 170         if (a->is_data && !b->is_data)
 171                 return -1;
 172
 173         if (!a->is_data && b->is_data)
 174                 return 1;
 175
 176         result = a->name_index - b->name_index;
 177         if (result)
 178                 return result;
 179
 180         result = a->name_len - b->name_len;
 181         if (result)
 182                 return result;
 183
 184         return memcmp(a->name, b->name, a->name_len);
 185 }
 186
 187 RB_GENERATE_INTERNAL(ext4_xattr_tree, ext4_xattr_item, node,
 188                      ext4_xattr_item_cmp, static inline)
 189
 190 static struct ext4_xattr_item *
 191 ext4_xattr_item_alloc(uint8_t name_index, const char *name, size_t name_len)
 192 {
 193         struct ext4_xattr_item *item;
 194         item = malloc(sizeof(struct ext4_xattr_item) + name_len);
 195         if (!item)
 196                 return NULL;
 197
 198         item->name_index = name_index;
 199         item->name = (char *)(item + 1);
 200         item->name_len = name_len;
 201         item->data = NULL;
 202         item->data_size = 0;
 203         item->in_inode = false;
 204
 205         memset(&item->node, 0, sizeof(item->node));
 206         memcpy(item->name, name, name_len);
 207
 208         if (name_index == EXT4_XATTR_INDEX_SYSTEM &&
 209             name_len == 4 &&
 210             !memcmp(name, "data", 4))
 211                 item->is_data = true;
 212         else
 213                 item->is_data = false;
 214
 215         return item;
 216 }
 217
 218 static int ext4_xattr_item_alloc_data(struct ext4_xattr_item *item,
 219                                       const void *orig_data, size_t data_size)
 220 {
 221         void *data = NULL;
 222         ext4_assert(!item->data);
 223         data = malloc(data_size);
 224         if (!data)
 225                 return ENOMEM;
 226
 227         if (orig_data)
 228                 memcpy(data, orig_data, data_size);
 229
 230         item->data = data;
 231         item->data_size = data_size;
 232         return EOK;
 233 }
 234
 235 static void ext4_xattr_item_free_data(struct ext4_xattr_item *item)
 236 {
 237         ext4_assert(item->data);
 238         free(item->data);
 239         item->data = NULL;
 240         item->data_size = 0;
 241 }
 242
 243 static int ext4_xattr_item_resize_data(struct ext4_xattr_item *item,
 244                                        size_t new_data_size)
 245 {
 246         if (new_data_size != item->data_size) {
 247                 void *new_data;
 248                 new_data = realloc(item->data, new_data_size);
 249                 if (!new_data)
 250                         return ENOMEM;
 251
 252                 item->data = new_data;
 253                 item->data_size = new_data_size;
 254         }
 255         return EOK;
 256 }
 257
 258 static void ext4_xattr_item_free(struct ext4_xattr_item *item)
 259 {
 260         if (item->data)
 261                 ext4_xattr_item_free_data(item);
 262
 263         free(item);
 264 }
 265
 266 static void *ext4_xattr_entry_data(struct ext4_xattr_ref *xattr_ref,
 267                                    struct ext4_xattr_entry *entry,
 268                                    bool in_inode)
 269 {
 270         char *ret;
 271         if (in_inode) {
 272                 struct ext4_xattr_ibody_header *header;
 273                 struct ext4_xattr_entry *first_entry;
 274                 int16_t inode_size =
 275                     ext4_get16(&xattr_ref->fs->sb, inode_size);
 276                 header = EXT4_XATTR_IHDR(&xattr_ref->fs->sb,
 277                                 xattr_ref->inode_ref->inode);
 278                 first_entry = EXT4_XATTR_IFIRST(header);
 279
 280                 ret = ((char *)first_entry + to_le16(entry->e_value_offs));
 281                 if (ret + EXT4_XATTR_SIZE(to_le32(entry->e_value_size)) -
 282                         (char *)xattr_ref->inode_ref->inode > inode_size)
 283                         ret = NULL;
 284
 285                 return ret;
 286
 287         }
 288         int32_t block_size = ext4_sb_get_block_size(&xattr_ref->fs->sb);
 289         ret = ((char *)xattr_ref->block.data + to_le16(entry->e_value_offs));
 290         if (ret + EXT4_XATTR_SIZE(to_le32(entry->e_value_size)) -
 291                         (char *)xattr_ref->block.data > block_size)
 292                 ret = NULL;
 293         return ret;
 294 }
 295
 296 static int ext4_xattr_block_fetch(struct ext4_xattr_ref *xattr_ref)
 297 {
 298         int ret = EOK;
 299         size_t size_rem;
 300         void *data;
 301         struct ext4_xattr_entry *entry = NULL;
 302
 303         ext4_assert(xattr_ref->block.data);
 304         entry = EXT4_XATTR_BFIRST(&xattr_ref->block);
 305
 306         size_rem = ext4_sb_get_block_size(&xattr_ref->fs->sb);
 307         for (; size_rem > 0 && !EXT4_XATTR_IS_LAST_ENTRY(entry);
 308              entry = EXT4_XATTR_NEXT(entry),
 309              size_rem -= EXT4_XATTR_LEN(entry->e_name_len)) {
 310                 struct ext4_xattr_item *item;
 311                 char *e_name = EXT4_XATTR_NAME(entry);
 312
 313                 data = ext4_xattr_entry_data(xattr_ref, entry, false);
 314                 if (!data) {
 315                         ret = EIO;
 316                         goto Finish;
 317                 }
 318
 319                 item = ext4_xattr_item_alloc(entry->e_name_index, e_name,
 320                                              (size_t)entry->e_name_len);
 321                 if (!item) {
 322                         ret = ENOMEM;
 323                         goto Finish;
 324                 }
 325                 if (ext4_xattr_item_alloc_data(
 326                         item, data, to_le32(entry->e_value_size)) != EOK) {
 327                         ext4_xattr_item_free(item);
 328                         ret = ENOMEM;
 329                         goto Finish;
 330                 }
 331                 RB_INSERT(ext4_xattr_tree, &xattr_ref->root, item);
 332                 xattr_ref->block_size_rem -=
 333                         EXT4_XATTR_SIZE(item->data_size) +
 334                         EXT4_XATTR_LEN(item->name_len);
 335                 xattr_ref->ea_size += EXT4_XATTR_SIZE(item->data_size) +
 336                                       EXT4_XATTR_LEN(item->name_len);
 337         }
 338
 339 Finish:
 340         return ret;
 341 }
 342
 343 static int ext4_xattr_inode_fetch(struct ext4_xattr_ref *xattr_ref)
 344 {
 345         void *data;
 346         size_t size_rem;
 347         int ret = EOK;
 348         struct ext4_xattr_ibody_header *header = NULL;
 349         struct ext4_xattr_entry *entry = NULL;
 350         uint16_t inode_size = ext4_get16(&xattr_ref->fs->sb, inode_size);
 351         uint16_t extra_isize = ext4_inode_get_extra_isize(&xattr_ref->fs->sb,
 352                                         xattr_ref->inode_ref->inode);
 353
 354         header = EXT4_XATTR_IHDR(&xattr_ref->fs->sb,
 355                                  xattr_ref->inode_ref->inode);
 356         entry = EXT4_XATTR_IFIRST(header);
 357
 358         size_rem = inode_size - EXT4_GOOD_OLD_INODE_SIZE -
 359                    extra_isize;
 360         for (; size_rem > 0 && !EXT4_XATTR_IS_LAST_ENTRY(entry);
 361              entry = EXT4_XATTR_NEXT(entry),
 362              size_rem -= EXT4_XATTR_LEN(entry->e_name_len)) {
 363                 struct ext4_xattr_item *item;
 364                 char *e_name = EXT4_XATTR_NAME(entry);
 365
 366                 data = ext4_xattr_entry_data(xattr_ref, entry, true);
 367                 if (!data) {
 368                         ret = EIO;
 369                         goto Finish;
 370                 }
 371
 372                 item = ext4_xattr_item_alloc(entry->e_name_index, e_name,
 373                                              (size_t)entry->e_name_len);
 374                 if (!item) {
 375                         ret = ENOMEM;
 376                         goto Finish;
 377                 }
 378                 if (ext4_xattr_item_alloc_data(
 379                         item, data, to_le32(entry->e_value_size)) != EOK) {
 380                         ext4_xattr_item_free(item);
 381                         ret = ENOMEM;
 382                         goto Finish;
 383                 }
 384                 item->in_inode = true;
 385                 RB_INSERT(ext4_xattr_tree, &xattr_ref->root, item);
 386                 xattr_ref->inode_size_rem -=
 387                         EXT4_XATTR_SIZE(item->data_size) +
 388                         EXT4_XATTR_LEN(item->name_len);
 389                 xattr_ref->ea_size += EXT4_XATTR_SIZE(item->data_size) +
 390                                       EXT4_XATTR_LEN(item->name_len);
 391         }
 392
 393 Finish:
 394         return ret;
 395 }
 396
 397 static size_t ext4_xattr_inode_space(struct ext4_xattr_ref *xattr_ref)
 398 {
 399         uint16_t inode_size = ext4_get16(&xattr_ref->fs->sb, inode_size);
 400         uint16_t extra_isize = ext4_inode_get_extra_isize(&xattr_ref->fs->sb,
 401                                         xattr_ref->inode_ref->inode);
 402         uint16_t size_rem = inode_size - EXT4_GOOD_OLD_INODE_SIZE -
 403                             extra_isize;
 404         return size_rem;
 405 }
 406
 407 static size_t ext4_xattr_block_space(struct ext4_xattr_ref *xattr_ref)
 408 {
 409         return ext4_sb_get_block_size(&xattr_ref->fs->sb);
 410 }
 411
 412 static int ext4_xattr_fetch(struct ext4_xattr_ref *xattr_ref)
 413 {
 414         int ret = EOK;
 415         uint16_t inode_size = ext4_get16(&xattr_ref->fs->sb, inode_size);
 416         if (inode_size > EXT4_GOOD_OLD_INODE_SIZE) {
 417                 ret = ext4_xattr_inode_fetch(xattr_ref);
 418                 if (ret != EOK)
 419                         return ret;
 420         }
 421
 422         if (xattr_ref->block_loaded)
 423                 ret = ext4_xattr_block_fetch(xattr_ref);
 424
 425         xattr_ref->dirty = false;
 426         return ret;
 427 }
 428
 429 static struct ext4_xattr_item *
 430 ext4_xattr_lookup_item(struct ext4_xattr_ref *xattr_ref, uint8_t name_index,
 431                        const char *name, size_t name_len)
 432 {
 433         struct ext4_xattr_item tmp = {
 434                 .name_index = name_index,
 435                 .name = (char *)name, /*RB_FIND - won't touch this string*/
 436                 .name_len = name_len,
 437         };
 438         if (name_index == EXT4_XATTR_INDEX_SYSTEM &&
 439             name_len == 4 &&
 440             !memcmp(name, "data", 4))
 441                 tmp.is_data = true;
 442
 443         return RB_FIND(ext4_xattr_tree, &xattr_ref->root, &tmp);
 444 }
 445
 446 static struct ext4_xattr_item *
 447 ext4_xattr_insert_item(struct ext4_xattr_ref *xattr_ref, uint8_t name_index,
 448                        const char *name, size_t name_len, const void *data,
 449                        size_t data_size)
 450 {
 451         struct ext4_xattr_item *item;
 452         item = ext4_xattr_item_alloc(name_index, name, name_len);
 453         if (!item)
 454                 return NULL;
 455
 456         if ((xattr_ref->ea_size + EXT4_XATTR_SIZE(data_size) +
 457                 EXT4_XATTR_LEN(item->name_len)
 458                         >
 459             ext4_xattr_inode_space(xattr_ref) -
 460                 sizeof(struct ext4_xattr_ibody_header))
 461                 &&
 462             (xattr_ref->ea_size + EXT4_XATTR_SIZE(data_size) +
 463                 EXT4_XATTR_LEN(item->name_len) >
 464             ext4_xattr_block_space(xattr_ref) -
 465                 sizeof(struct ext4_xattr_header))) {
 466                 ext4_xattr_item_free(item);
 467
 468                 return NULL;
 469         }
 470         item->in_inode = true;
 471         if (xattr_ref->inode_size_rem -
 472             (int32_t)EXT4_XATTR_SIZE(data_size) -
 473             (int32_t)EXT4_XATTR_LEN(item->name_len) < 0) {
 474                 if (xattr_ref->block_size_rem -
 475                     (int32_t)EXT4_XATTR_SIZE(data_size) -
 476                     (int32_t)EXT4_XATTR_LEN(item->name_len) < 0)
 477                         return NULL;
 478
 479                 item->in_inode = false;
 480         }
 481         if (ext4_xattr_item_alloc_data(item, data, data_size) != EOK) {
 482                 ext4_xattr_item_free(item);
 483                 return NULL;
 484         }
 485         RB_INSERT(ext4_xattr_tree, &xattr_ref->root, item);
 486         xattr_ref->ea_size +=
 487             EXT4_XATTR_SIZE(item->data_size) + EXT4_XATTR_LEN(item->name_len);
 488         if (item->in_inode) {
 489                 xattr_ref->inode_size_rem -=
 490                         EXT4_XATTR_SIZE(item->data_size) +
 491                         EXT4_XATTR_LEN(item->name_len);
 492         } else {
 493                 xattr_ref->block_size_rem -=
 494                         EXT4_XATTR_SIZE(item->data_size) +
 495                         EXT4_XATTR_LEN(item->name_len);
 496         }
 497         xattr_ref->dirty = true;
 498         return item;
 499 }
 500
 501 static int ext4_xattr_remove_item(struct ext4_xattr_ref *xattr_ref,
 502                                   uint8_t name_index, const char *name,
 503                                   size_t name_len)
 504 {
 505         int ret = ENOENT;
 506         struct ext4_xattr_item *item =
 507             ext4_xattr_lookup_item(xattr_ref, name_index, name, name_len);
 508         if (item) {
 509                 if (item == xattr_ref->iter_from)
 510                         xattr_ref->iter_from =
 511                             RB_NEXT(ext4_xattr_tree, &xattr_ref->root, item);
 512
 513                 xattr_ref->ea_size -= EXT4_XATTR_SIZE(item->data_size) +
 514                                       EXT4_XATTR_LEN(item->name_len);
 515
 516                 if (item->in_inode) {
 517                         xattr_ref->inode_size_rem +=
 518                                 EXT4_XATTR_SIZE(item->data_size) +
 519                                 EXT4_XATTR_LEN(item->name_len);
 520                 } else {
 521                         xattr_ref->block_size_rem +=
 522                                 EXT4_XATTR_SIZE(item->data_size) +
 523                                 EXT4_XATTR_LEN(item->name_len);
 524                 }
 525
 526                 RB_REMOVE(ext4_xattr_tree, &xattr_ref->root, item);
 527                 ext4_xattr_item_free(item);
 528                 xattr_ref->dirty = true;
 529                 ret = EOK;
 530         }
 531         return ret;
 532 }
 533
 534 static int ext4_xattr_resize_item(struct ext4_xattr_ref *xattr_ref,
 535                                   struct ext4_xattr_item *item,
 536                                   size_t new_data_size)
 537 {
 538         int ret = EOK;
 539         bool to_inode = false, to_block = false;
 540         size_t old_data_size = item->data_size;
 541         int32_t orig_room_size = item->in_inode ?
 542                 xattr_ref->inode_size_rem :
 543                 xattr_ref->block_size_rem;
 544
 545         /*
 546          * Check if we can hold this entry in both in-inode and
 547          * on-block form
 548          */
 549         if ((xattr_ref->ea_size - EXT4_XATTR_SIZE(old_data_size) +
 550                 EXT4_XATTR_SIZE(new_data_size)
 551                         >
 552             ext4_xattr_inode_space(xattr_ref) -
 553                 sizeof(struct ext4_xattr_ibody_header))
 554                 &&
 555             (xattr_ref->ea_size - EXT4_XATTR_SIZE(old_data_size) +
 556                 EXT4_XATTR_SIZE(new_data_size)
 557                         >
 558             ext4_xattr_block_space(xattr_ref) -
 559                 sizeof(struct ext4_xattr_header))) {
 560
 561                 return ENOSPC;
 562         }
 563
 564         /*
 565          * More complicated case: we do not allow entries stucking in
 566          * the middle between in-inode space and on-block space, so
 567          * the entry has to stay in either inode space or block space.
 568          */
 569         if (item->in_inode) {
 570                 if (xattr_ref->inode_size_rem +
 571                                 (int32_t)EXT4_XATTR_SIZE(old_data_size) -
 572                                 (int32_t)EXT4_XATTR_SIZE(new_data_size) < 0) {
 573                         if (xattr_ref->block_size_rem -
 574                                         (int32_t)EXT4_XATTR_SIZE(new_data_size) -
 575                                         (int32_t)EXT4_XATTR_LEN(item->name_len) < 0)
 576                                 return ENOSPC;
 577
 578                         to_block = true;
 579                 }
 580         } else {
 581                 if (xattr_ref->block_size_rem +
 582                                 (int32_t)EXT4_XATTR_SIZE(old_data_size) -
 583                                 (int32_t)EXT4_XATTR_SIZE(new_data_size) < 0) {
 584                         if (xattr_ref->inode_size_rem -
 585                                         (int32_t)EXT4_XATTR_SIZE(new_data_size) -
 586                                         (int32_t)EXT4_XATTR_LEN(item->name_len) < 0)
 587                                 return ENOSPC;
 588
 589                         to_inode = true;
 590                 }
 591         }
 592         ret = ext4_xattr_item_resize_data(item, new_data_size);
 593         if (ret != EOK)
 594                 return ret;
 595
 596         xattr_ref->ea_size =
 597             xattr_ref->ea_size -
 598             EXT4_XATTR_SIZE(old_data_size) +
 599             EXT4_XATTR_SIZE(new_data_size);
 600
 601         /*
 602          * This entry may originally lie in inode space or block space,
 603          * and it is going to be transferred to another place.
 604          */
 605         if (to_block) {
 606                 xattr_ref->inode_size_rem +=
 607                         EXT4_XATTR_SIZE(old_data_size) +
 608                         EXT4_XATTR_LEN(item->name_len);
 609                 xattr_ref->block_size_rem -=
 610                         EXT4_XATTR_SIZE(new_data_size) +
 611                         EXT4_XATTR_LEN(item->name_len);
 612                 item->in_inode = false;
 613         } else if (to_inode) {
 614                 xattr_ref->block_size_rem +=
 615                         EXT4_XATTR_SIZE(old_data_size) +
 616                         EXT4_XATTR_LEN(item->name_len);
 617                 xattr_ref->inode_size_rem -=
 618                         EXT4_XATTR_SIZE(new_data_size) +
 619                         EXT4_XATTR_LEN(item->name_len);
 620                 item->in_inode = true;
 621         } else {
 622                 /*
 623                  * No need to transfer as there is enough space for the entry
 624                  * to stay in inode space or block space it used to be.
 625                  */
 626                 orig_room_size +=
 627                         EXT4_XATTR_SIZE(old_data_size);
 628                 orig_room_size -=
 629                         EXT4_XATTR_SIZE(new_data_size);
 630                 if (item->in_inode)
 631                         xattr_ref->inode_size_rem = orig_room_size;
 632                 else
 633                         xattr_ref->block_size_rem = orig_room_size;
 634
 635         }
 636         xattr_ref->dirty = true;
 637         return ret;
 638 }
 639
 640 static void ext4_xattr_purge_items(struct ext4_xattr_ref *xattr_ref)
 641 {
 642         struct ext4_xattr_item *item, *save_item;
 643         RB_FOREACH_SAFE(item, ext4_xattr_tree, &xattr_ref->root, save_item) {
 644                 RB_REMOVE(ext4_xattr_tree, &xattr_ref->root, item);
 645                 ext4_xattr_item_free(item);
 646         }
 647         xattr_ref->ea_size = 0;
 648         xattr_ref->inode_size_rem = ext4_xattr_inode_space(xattr_ref) -
 649                 sizeof(struct ext4_xattr_ibody_header);
 650         if (xattr_ref->inode_size_rem < 0)
 651                 xattr_ref->inode_size_rem = 0;
 652
 653         xattr_ref->block_size_rem = ext4_xattr_block_space(xattr_ref) -
 654                 sizeof(struct ext4_xattr_header);
 655 }
 656
 657 static int ext4_xattr_try_alloc_block(struct ext4_xattr_ref *xattr_ref)
 658 {
 659         int ret = EOK;
 660
 661         ext4_fsblk_t xattr_block = 0;
 662         xattr_block = ext4_inode_get_file_acl(xattr_ref->inode_ref->inode,
 663                                               &xattr_ref->fs->sb);
 664         if (!xattr_block) {
 665                 ext4_fsblk_t goal =
 666                         ext4_fs_inode_to_goal_block(xattr_ref->inode_ref);
 667
 668                 ret = ext4_balloc_alloc_block(xattr_ref->inode_ref,
 669                                               goal,
 670                                               &xattr_block);
 671                 if (ret != EOK)
 672                         goto Finish;
 673
 674                 ret = ext4_trans_block_get(xattr_ref->fs->bdev, &xattr_ref->block,
 675                                      xattr_block);
 676                 if (ret != EOK) {
 677                         ext4_balloc_free_block(xattr_ref->inode_ref,
 678                                                xattr_block);
 679                         goto Finish;
 680                 }
 681
 682                 ext4_inode_set_file_acl(xattr_ref->inode_ref->inode,
 683                                         &xattr_ref->fs->sb, xattr_block);
 684                 xattr_ref->inode_ref->dirty = true;
 685                 xattr_ref->block_loaded = true;
 686         }
 687
 688 Finish:
 689         return ret;
 690 }
 691
 692 static void ext4_xattr_try_free_block(struct ext4_xattr_ref *xattr_ref)
 693 {
 694         ext4_fsblk_t xattr_block;
 695         xattr_block = ext4_inode_get_file_acl(xattr_ref->inode_ref->inode,
 696                                               &xattr_ref->fs->sb);
 697         ext4_inode_set_file_acl(xattr_ref->inode_ref->inode, &xattr_ref->fs->sb,
 698                                 0);
 699         ext4_block_set(xattr_ref->fs->bdev, &xattr_ref->block);
 700         ext4_balloc_free_block(xattr_ref->inode_ref, xattr_block);
 701         xattr_ref->inode_ref->dirty = true;
 702         xattr_ref->block_loaded = false;
 703 }
 704
 705 static void ext4_xattr_set_block_header(struct ext4_xattr_ref *xattr_ref)
 706 {
 707         struct ext4_xattr_header *block_header = NULL;
 708         block_header = EXT4_XATTR_BHDR(&xattr_ref->block);
 709
 710         memset(block_header, 0, sizeof(struct ext4_xattr_header));
 711         block_header->h_magic = EXT4_XATTR_MAGIC;
 712         block_header->h_refcount = to_le32(1);
 713         block_header->h_blocks = to_le32(1);
 714 }
 715
 716 static void
 717 ext4_xattr_set_inode_entry(struct ext4_xattr_item *item,
 718                            struct ext4_xattr_ibody_header *ibody_header,
 719                            struct ext4_xattr_entry *entry, void *ibody_data_ptr)
 720 {
 721         entry->e_name_len = (uint8_t)item->name_len;
 722         entry->e_name_index = item->name_index;
 723         entry->e_value_offs =
 724             to_le16((char *)ibody_data_ptr - (char *)EXT4_XATTR_IFIRST(ibody_header));
 725         entry->e_value_block = 0;
 726         entry->e_value_size = to_le32(item->data_size);
 727 }
 728
 729 static void ext4_xattr_set_block_entry(struct ext4_xattr_item *item,
 730                                        struct ext4_xattr_header *block_header,
 731                                        struct ext4_xattr_entry *block_entry,
 732                                        void *block_data_ptr)
 733 {
 734         block_entry->e_name_len = (uint8_t)item->name_len;
 735         block_entry->e_name_index = item->name_index;
 736         block_entry->e_value_offs =
 737             to_le16((char *)block_data_ptr - (char *)block_header);
 738         block_entry->e_value_block = 0;
 739         block_entry->e_value_size = to_le32(item->data_size);
 740 }
 741
 742 static int ext4_xattr_write_to_disk(struct ext4_xattr_ref *xattr_ref)
 743 {
 744         int ret = EOK;
 745         bool block_modified = false;
 746         void *ibody_data = NULL;
 747         void *block_data = NULL;
 748         struct ext4_xattr_item *item, *save_item;
 749         size_t inode_size_rem, block_size_rem;
 750         struct ext4_xattr_ibody_header *ibody_header = NULL;
 751         struct ext4_xattr_header *block_header = NULL;
 752         struct ext4_xattr_entry *entry = NULL;
 753         struct ext4_xattr_entry *block_entry = NULL;
 754
 755         inode_size_rem = ext4_xattr_inode_space(xattr_ref);
 756         block_size_rem = ext4_xattr_block_space(xattr_ref);
 757         if (inode_size_rem > sizeof(struct ext4_xattr_ibody_header)) {
 758                 ibody_header = EXT4_XATTR_IHDR(&xattr_ref->fs->sb,
 759                                                xattr_ref->inode_ref->inode);
 760                 entry = EXT4_XATTR_IFIRST(ibody_header);
 761         }
 762
 763         if (!xattr_ref->dirty)
 764                 goto Finish;
 765         /* If there are enough spaces in the ibody EA table.*/
 766         if (inode_size_rem > sizeof(struct ext4_xattr_ibody_header)) {
 767                 memset(ibody_header, 0, inode_size_rem);
 768                 ibody_header->h_magic = EXT4_XATTR_MAGIC;
 769                 ibody_data = (char *)ibody_header + inode_size_rem;
 770                 inode_size_rem -= sizeof(struct ext4_xattr_ibody_header);
 771
 772                 xattr_ref->inode_ref->dirty = true;
 773         }
 774         /* If we need an extra block to hold the EA entries*/
 775         if (xattr_ref->ea_size > inode_size_rem) {
 776                 if (!xattr_ref->block_loaded) {
 777                         ret = ext4_xattr_try_alloc_block(xattr_ref);
 778                         if (ret != EOK)
 779                                 goto Finish;
 780                 }
 781                 block_header = EXT4_XATTR_BHDR(&xattr_ref->block);
 782                 block_entry = EXT4_XATTR_BFIRST(&xattr_ref->block);
 783                 ext4_xattr_set_block_header(xattr_ref);
 784                 block_data = (char *)block_header + block_size_rem;
 785                 block_size_rem -= sizeof(struct ext4_xattr_header);
 786
 787                 ext4_trans_set_block_dirty(xattr_ref->block.buf);
 788         } else {
 789                 /* We don't need an extra block.*/
 790                 if (xattr_ref->block_loaded) {
 791                         block_header = EXT4_XATTR_BHDR(&xattr_ref->block);
 792                         block_header->h_refcount =
 793                             to_le32(to_le32(block_header->h_refcount) - 1);
 794                         if (!block_header->h_refcount) {
 795                                 ext4_xattr_try_free_block(xattr_ref);
 796                                 block_header = NULL;
 797                         } else {
 798                                 block_entry =
 799                                     EXT4_XATTR_BFIRST(&xattr_ref->block);
 800                                 block_data =
 801                                     (char *)block_header + block_size_rem;
 802                                 block_size_rem -=
 803                                     sizeof(struct ext4_xattr_header);
 804                                 ext4_inode_set_file_acl(
 805                                     xattr_ref->inode_ref->inode,
 806                                     &xattr_ref->fs->sb, 0);
 807
 808                                 xattr_ref->inode_ref->dirty = true;
 809                                 ext4_trans_set_block_dirty(xattr_ref->block.buf);
 810                         }
 811                 }
 812         }
 813         RB_FOREACH_SAFE(item, ext4_xattr_tree, &xattr_ref->root, save_item)
 814         {
 815                 if (EXT4_XATTR_SIZE(item->data_size) +
 816                         EXT4_XATTR_LEN(item->name_len) <=
 817                     inode_size_rem) {
 818                         ibody_data = (char *)ibody_data -
 819                                      EXT4_XATTR_SIZE(item->data_size);
 820                         ext4_xattr_set_inode_entry(item, ibody_header, entry,
 821                                                    ibody_data);
 822                         memcpy(EXT4_XATTR_NAME(entry), item->name,
 823                                item->name_len);
 824                         memcpy(ibody_data, item->data, item->data_size);
 825                         entry = EXT4_XATTR_NEXT(entry);
 826                         inode_size_rem -= EXT4_XATTR_SIZE(item->data_size) +
 827                                           EXT4_XATTR_LEN(item->name_len);
 828
 829                         xattr_ref->inode_ref->dirty = true;
 830                         continue;
 831                 }
 832                 if (EXT4_XATTR_SIZE(item->data_size) +
 833                         EXT4_XATTR_LEN(item->name_len) >
 834                     block_size_rem) {
 835                         ret = ENOSPC;
 836                         ext4_dbg(DEBUG_XATTR, "IMPOSSIBLE ENOSPC AS WE DID INSPECTION!\n");
 837                         ext4_assert(0);
 838                 }
 839                 block_data =
 840                     (char *)block_data - EXT4_XATTR_SIZE(item->data_size);
 841                 ext4_xattr_set_block_entry(item, block_header, block_entry,
 842                                            block_data);
 843                 memcpy(EXT4_XATTR_NAME(block_entry), item->name,
 844                        item->name_len);
 845                 memcpy(block_data, item->data, item->data_size);
 846                 block_entry = EXT4_XATTR_NEXT(block_entry);
 847                 block_size_rem -= EXT4_XATTR_SIZE(item->data_size) +
 848                                   EXT4_XATTR_LEN(item->name_len);
 849
 850                 block_modified = true;
 851         }
 852         xattr_ref->dirty = false;
 853         if (block_modified) {
 854                 ext4_xattr_rehash(block_header,
 855                                   EXT4_XATTR_BFIRST(&xattr_ref->block));
 856                 ext4_xattr_set_block_checksum(xattr_ref->inode_ref,
 857                                               xattr_ref->block.lb_id,
 858                                               block_header);
 859                 ext4_trans_set_block_dirty(xattr_ref->block.buf);
 860         }
 861
 862 Finish:
 863         return ret;
 864 }
 865
 866 void ext4_fs_xattr_iterate(struct ext4_xattr_ref *ref,
 867                            int (*iter)(struct ext4_xattr_ref *ref,
 868                                      struct ext4_xattr_item *item))
 869 {
 870         struct ext4_xattr_item *item;
 871         if (!ref->iter_from)
 872                 ref->iter_from = RB_MIN(ext4_xattr_tree, &ref->root);
 873
 874         RB_FOREACH_FROM(item, ext4_xattr_tree, ref->iter_from)
 875         {
 876                 int ret = EXT4_XATTR_ITERATE_CONT;
 877                 if (iter)
 878                         iter(ref, item);
 879
 880                 if (ret != EXT4_XATTR_ITERATE_CONT) {
 881                         if (ret == EXT4_XATTR_ITERATE_STOP)
 882                                 ref->iter_from = NULL;
 883
 884                         break;
 885                 }
 886         }
 887 }
 888
 889 void ext4_fs_xattr_iterate_reset(struct ext4_xattr_ref *ref)
 890 {
 891         ref->iter_from = NULL;
 892 }
 893
 894 int ext4_fs_set_xattr(struct ext4_xattr_ref *ref, uint8_t name_index,
 895                       const char *name, size_t name_len, const void *data,
 896                       size_t data_size, bool replace)
 897 {
 898         int ret = EOK;
 899         struct ext4_xattr_item *item =
 900             ext4_xattr_lookup_item(ref, name_index, name, name_len);
 901         if (replace) {
 902                 if (!item) {
 903                         ret = ENODATA;
 904                         goto Finish;
 905                 }
 906                 if (item->data_size != data_size)
 907                         ret = ext4_xattr_resize_item(ref, item, data_size);
 908
 909                 if (ret != EOK) {
 910                         goto Finish;
 911                 }
 912                 memcpy(item->data, data, data_size);
 913         } else {
 914                 if (item) {
 915                         ret = EEXIST;
 916                         goto Finish;
 917                 }
 918                 item = ext4_xattr_insert_item(ref, name_index, name, name_len,
 919                                               data, data_size);
 920                 if (!item)
 921                         ret = ENOMEM;
 922         }
 923 Finish:
 924         return ret;
 925 }
 926
 927 int ext4_fs_remove_xattr(struct ext4_xattr_ref *ref, uint8_t name_index,
 928                          const char *name, size_t name_len)
 929 {
 930         return ext4_xattr_remove_item(ref, name_index, name, name_len);
 931 }
 932
 933 int ext4_fs_get_xattr(struct ext4_xattr_ref *ref, uint8_t name_index,
 934                       const char *name, size_t name_len, void *buf,
 935                       size_t buf_size, size_t *data_size)
 936 {
 937         int ret = EOK;
 938         size_t item_size = 0;
 939         struct ext4_xattr_item *item =
 940             ext4_xattr_lookup_item(ref, name_index, name, name_len);
 941
 942         if (!item) {
 943                 ret = ENODATA;
 944                 goto Finish;
 945         }
 946         item_size = item->data_size;
 947         if (buf_size > item_size)
 948                 buf_size = item_size;
 949
 950         if (buf)
 951                 memcpy(buf, item->data, buf_size);
 952
 953 Finish:
 954         if (data_size)
 955                 *data_size = item_size;
 956
 957         return ret;
 958 }
 959
 960 int ext4_fs_get_xattr_ref(struct ext4_fs *fs, struct ext4_inode_ref *inode_ref,
 961                           struct ext4_xattr_ref *ref)
 962 {
 963         int rc;
 964         ext4_fsblk_t xattr_block;
 965         xattr_block = ext4_inode_get_file_acl(inode_ref->inode, &fs->sb);
 966         RB_INIT(&ref->root);
 967         ref->ea_size = 0;
 968         ref->iter_from = NULL;
 969         if (xattr_block) {
 970                 rc = ext4_trans_block_get(fs->bdev, &ref->block, xattr_block);
 971                 if (rc != EOK)
 972                         return EIO;
 973
 974                 ref->block_loaded = true;
 975         } else
 976                 ref->block_loaded = false;
 977
 978         ref->inode_ref = inode_ref;
 979         ref->fs = fs;
 980
 981         ref->inode_size_rem = ext4_xattr_inode_space(ref) -
 982                 sizeof(struct ext4_xattr_ibody_header);
 983         if (ref->inode_size_rem < 0)
 984                 ref->inode_size_rem = 0;
 985
 986         ref->block_size_rem = ext4_xattr_block_space(ref) -
 987                 sizeof(struct ext4_xattr_header);
 988         rc = ext4_xattr_fetch(ref);
 989         if (rc != EOK) {
 990                 ext4_xattr_purge_items(ref);
 991                 if (xattr_block)
 992                         ext4_block_set(fs->bdev, &ref->block);
 993
 994                 ref->block_loaded = false;
 995                 return rc;
 996         }
 997         return EOK;
 998 }
 999
1000 void ext4_fs_put_xattr_ref(struct ext4_xattr_ref *ref)
1001 {
1002         ext4_xattr_write_to_disk(ref);
1003         if (ref->block_loaded) {
1004                 ext4_block_set(ref->fs->bdev, &ref->block);
1005                 ref->block_loaded = false;
1006         }
1007         ext4_xattr_purge_items(ref);
1008         ref->inode_ref = NULL;
1009         ref->fs = NULL;
1010 }
1011
1012 struct xattr_prefix {
1013         const char *prefix;
1014         uint8_t name_index;
1015 };
1016
1017 static const struct xattr_prefix prefix_tbl[] = {
1018     {"user.", EXT4_XATTR_INDEX_USER},
1019     {"system.posix_acl_access", EXT4_XATTR_INDEX_POSIX_ACL_ACCESS},
1020     {"system.posix_acl_default", EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT},
1021     {"trusted.", EXT4_XATTR_INDEX_TRUSTED},
1022     {"security.", EXT4_XATTR_INDEX_SECURITY},
1023     {"system.", EXT4_XATTR_INDEX_SYSTEM},
1024     {"system.richacl", EXT4_XATTR_INDEX_RICHACL},
1025     {NULL, 0},
1026 };
1027
1028 const char *ext4_extract_xattr_name(const char *full_name, size_t full_name_len,
1029                               uint8_t *name_index, size_t *name_len,
1030                               bool *found)
1031 {
1032         int i;
1033         ext4_assert(name_index);
1034         ext4_assert(found);
1035
1036         *found = false;
1037
1038         if (!full_name_len) {
1039                 if (name_len)
1040                         *name_len = 0;
1041
1042                 return NULL;
1043         }
1044
1045         for (i = 0; prefix_tbl[i].prefix; i++) {
1046                 size_t prefix_len = strlen(prefix_tbl[i].prefix);
1047                 if (full_name_len >= prefix_len &&
1048                     !memcmp(full_name, prefix_tbl[i].prefix, prefix_len)) {
1049                         bool require_name =
1050                                 prefix_tbl[i].prefix[prefix_len - 1] == '.';
1051                         *name_index = prefix_tbl[i].name_index;
1052                         if (name_len)
1053                                 *name_len = full_name_len - prefix_len;
1054
1055                         if (!(full_name_len - prefix_len) && require_name)
1056                                 return NULL;
1057
1058                         *found = true;
1059                         if (require_name)
1060                                 return full_name + prefix_len;
1061
1062                         return NULL;
1063                 }
1064         }
1065         if (name_len)
1066                 *name_len = 0;
1067
1068         return NULL;
1069 }
1070
1071 const char *ext4_get_xattr_name_prefix(uint8_t name_index,
1072                                        size_t *ret_prefix_len)
1073 {
1074         int i;
1075
1076         for (i = 0; prefix_tbl[i].prefix; i++) {
1077                 size_t prefix_len = strlen(prefix_tbl[i].prefix);
1078                 if (prefix_tbl[i].name_index == name_index) {
1079                         if (ret_prefix_len)
1080                                 *ret_prefix_len = prefix_len;
1081
1082                         return prefix_tbl[i].prefix;
1083                 }
1084         }
1085         if (ret_prefix_len)
1086                 *ret_prefix_len = 0;
1087
1088         return NULL;
1089 }
1090
1091 /**
1092  * @}
1093  */