lwext4/ext4_extent_full.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 #include "ext4_config.h"
  30 #include "ext4_blockdev.h"
  31 #include "ext4_fs.h"
  32 #include "ext4_super.h"
  33 #include "ext4_crc32c.h"
  34 #include "ext4_balloc.h"
  35 #include "ext4_debug.h"
  36
  37 #include <stdlib.h>
  38 #include <string.h>
  39 #include <inttypes.h>
  40 #include <stddef.h>
  41
  42 #include "ext4_extent.h"
  43
  44 #if CONFIG_EXTENT_FULL
  45
  46 /*
  47  * used by extent splitting.
  48  */
  49 #define EXT4_EXT_MARK_UNWRIT1 0x02 /* mark first half unwritten */
  50 #define EXT4_EXT_MARK_UNWRIT2 0x04 /* mark second half unwritten */
  51 #define EXT4_EXT_DATA_VALID1 0x08  /* first half contains valid data */
  52 #define EXT4_EXT_DATA_VALID2 0x10  /* second half contains valid data */
  53 #define EXT4_EXT_NO_COMBINE 0x20   /* do not combine two extents */
  54
  55 static struct ext4_extent_tail *
  56 find_ext4_extent_tail(struct ext4_extent_header *eh)
  57 {
  58         return (struct ext4_extent_tail *)(((char *)eh) +
  59                                            EXT4_EXTENT_TAIL_OFFSET(eh));
  60 }
  61
  62 static struct ext4_extent_header *ext_inode_hdr(struct ext4_inode *inode)
  63 {
  64         return (struct ext4_extent_header *)inode->blocks;
  65 }
  66
  67 static struct ext4_extent_header *ext_block_hdr(struct ext4_block *block)
  68 {
  69         return (struct ext4_extent_header *)block->data;
  70 }
  71
  72 static uint16_t ext_depth(struct ext4_inode *inode)
  73 {
  74         return to_le16(ext_inode_hdr(inode)->depth);
  75 }
  76
  77 static uint16_t ext4_ext_get_actual_len(struct ext4_extent *ext)
  78 {
  79         return (to_le16(ext->block_count) <= EXT_INIT_MAX_LEN
  80                     ? to_le16(ext->block_count)
  81                     : (to_le16(ext->block_count) - EXT_INIT_MAX_LEN));
  82 }
  83
  84 static void ext4_ext_mark_initialized(struct ext4_extent *ext)
  85 {
  86         ext->block_count = to_le16(ext4_ext_get_actual_len(ext));
  87 }
  88
  89 static void ext4_ext_mark_unwritten(struct ext4_extent *ext)
  90 {
  91         ext->block_count |= to_le16(EXT_INIT_MAX_LEN);
  92 }
  93
  94 static int ext4_ext_is_unwritten(struct ext4_extent *ext)
  95 {
  96         /* Extent with ee_len of 0x8000 is treated as an initialized extent */
  97         return (to_le16(ext->block_count) > EXT_INIT_MAX_LEN);
  98 }
  99
 100 /*
 101  * ext4_ext_pblock:
 102  * combine low and high parts of physical block number into ext4_fsblk_t
 103  */
 104 static ext4_fsblk_t ext4_ext_pblock(struct ext4_extent *ex)
 105 {
 106         ext4_fsblk_t block;
 107
 108         block = to_le32(ex->start_lo);
 109         block |= ((ext4_fsblk_t)to_le16(ex->start_hi) << 31) << 1;
 110         return block;
 111 }
 112
 113 /*
 114  * ext4_idx_pblock:
 115  * combine low and high parts of a leaf physical block number into ext4_fsblk_t
 116  */
 117 static ext4_fsblk_t ext4_idx_pblock(struct ext4_extent_index *ix)
 118 {
 119         ext4_fsblk_t block;
 120
 121         block = to_le32(ix->leaf_lo);
 122         block |= ((ext4_fsblk_t)to_le16(ix->leaf_hi) << 31) << 1;
 123         return block;
 124 }
 125
 126 /*
 127  * ext4_ext_store_pblock:
 128  * stores a large physical block number into an extent struct,
 129  * breaking it into parts
 130  */
 131 static void ext4_ext_store_pblock(struct ext4_extent *ex, ext4_fsblk_t pb)
 132 {
 133         ex->start_lo = to_le32((uint32_t)(pb & 0xffffffff));
 134         ex->start_hi = to_le16((uint16_t)((pb >> 32)) & 0xffff);
 135 }
 136
 137 /*
 138  * ext4_idx_store_pblock:
 139  * stores a large physical block number into an index struct,
 140  * breaking it into parts
 141  */
 142 static void ext4_idx_store_pblock(struct ext4_extent_index *ix, ext4_fsblk_t pb)
 143 {
 144         ix->leaf_lo = to_le32((uint32_t)(pb & 0xffffffff));
 145         ix->leaf_hi = to_le16((uint16_t)((pb >> 32)) & 0xffff);
 146 }
 147
 148 static int ext4_allocate_single_block(struct ext4_inode_ref *inode_ref,
 149                                       ext4_fsblk_t goal,
 150                                       ext4_fsblk_t *blockp)
 151 {
 152         return ext4_balloc_alloc_block(inode_ref, goal, blockp);
 153 }
 154
 155 static ext4_fsblk_t ext4_new_meta_blocks(struct ext4_inode_ref *inode_ref,
 156                                          ext4_fsblk_t goal,
 157                                          uint32_t flags __unused,
 158                                          uint32_t *count, int *errp)
 159 {
 160         ext4_fsblk_t block = 0;
 161
 162         *errp = ext4_allocate_single_block(inode_ref, goal, &block);
 163         if (count)
 164                 *count = 1;
 165         return block;
 166 }
 167
 168 static void ext4_ext_free_blocks(struct ext4_inode_ref *inode_ref,
 169                                  ext4_fsblk_t block, uint32_t count,
 170                                  uint32_t flags __unused)
 171 {
 172         ext4_balloc_free_blocks(inode_ref, block, count);
 173 }
 174
 175 static size_t ext4_ext_space_block(struct ext4_inode_ref *inode_ref)
 176 {
 177         size_t size;
 178         uint32_t block_size = ext4_sb_get_block_size(&inode_ref->fs->sb);
 179
 180         size = (block_size - sizeof(struct ext4_extent_header)) /
 181                sizeof(struct ext4_extent);
 182 #ifdef AGGRESSIVE_TEST
 183         if (size > 6)
 184                 size = 6;
 185 #endif
 186         return size;
 187 }
 188
 189 static size_t ext4_ext_space_block_idx(struct ext4_inode_ref *inode_ref)
 190 {
 191         size_t size;
 192         uint32_t block_size = ext4_sb_get_block_size(&inode_ref->fs->sb);
 193
 194         size = (block_size - sizeof(struct ext4_extent_header)) /
 195                sizeof(struct ext4_extent_index);
 196 #ifdef AGGRESSIVE_TEST
 197         if (size > 5)
 198                 size = 5;
 199 #endif
 200         return size;
 201 }
 202
 203 static size_t ext4_ext_space_root(struct ext4_inode_ref *inode_ref)
 204 {
 205         size_t size;
 206
 207         size = sizeof(inode_ref->inode->blocks);
 208         size -= sizeof(struct ext4_extent_header);
 209         size /= sizeof(struct ext4_extent);
 210 #ifdef AGGRESSIVE_TEST
 211         if (size > 3)
 212                 size = 3;
 213 #endif
 214         return size;
 215 }
 216
 217 static size_t ext4_ext_space_root_idx(struct ext4_inode_ref *inode_ref)
 218 {
 219         size_t size;
 220
 221         size = sizeof(inode_ref->inode->blocks);
 222         size -= sizeof(struct ext4_extent_header);
 223         size /= sizeof(struct ext4_extent_index);
 224 #ifdef AGGRESSIVE_TEST
 225         if (size > 4)
 226                 size = 4;
 227 #endif
 228         return size;
 229 }
 230
 231 static size_t ext4_ext_max_entries(struct ext4_inode_ref *inode_ref,
 232                                    uint32_t depth)
 233 {
 234         size_t max;
 235
 236         if (depth == ext_depth(inode_ref->inode)) {
 237                 if (depth == 0)
 238                         max = ext4_ext_space_root(inode_ref);
 239                 else
 240                         max = ext4_ext_space_root_idx(inode_ref);
 241         } else {
 242                 if (depth == 0)
 243                         max = ext4_ext_space_block(inode_ref);
 244                 else
 245                         max = ext4_ext_space_block_idx(inode_ref);
 246         }
 247
 248         return max;
 249 }
 250
 251 static ext4_fsblk_t ext4_ext_find_goal(struct ext4_inode_ref *inode_ref,
 252                                        struct ext4_extent_path *path,
 253                                        ext4_lblk_t block)
 254 {
 255         if (path) {
 256                 uint32_t depth = path->depth;
 257                 struct ext4_extent *ex;
 258
 259                 /*
 260                  * Try to predict block placement assuming that we are
 261                  * filling in a file which will eventually be
 262                  * non-sparse --- i.e., in the case of libbfd writing
 263                  * an ELF object sections out-of-order but in a way
 264                  * the eventually results in a contiguous object or
 265                  * executable file, or some database extending a table
 266                  * space file.  However, this is actually somewhat
 267                  * non-ideal if we are writing a sparse file such as
 268                  * qemu or KVM writing a raw image file that is going
 269                  * to stay fairly sparse, since it will end up
 270                  * fragmenting the file system's free space.  Maybe we
 271                  * should have some hueristics or some way to allow
 272                  * userspace to pass a hint to file system,
 273                  * especially if the latter case turns out to be
 274                  * common.
 275                  */
 276                 ex = path[depth].extent;
 277                 if (ex) {
 278                         ext4_fsblk_t ext_pblk = ext4_ext_pblock(ex);
 279                         ext4_lblk_t ext_block = to_le32(ex->first_block);
 280
 281                         if (block > ext_block)
 282                                 return ext_pblk + (block - ext_block);
 283                         else
 284                                 return ext_pblk - (ext_block - block);
 285                 }
 286
 287                 /* it looks like index is empty;
 288                  * try to find starting block from index itself */
 289                 if (path[depth].block.lb_id)
 290                         return path[depth].block.lb_id;
 291         }
 292
 293         /* OK. use inode's group */
 294         return ext4_fs_inode_to_goal_block(inode_ref);
 295 }
 296
 297 /*
 298  * Allocation for a meta data block
 299  */
 300 static ext4_fsblk_t ext4_ext_new_meta_block(struct ext4_inode_ref *inode_ref,
 301                                             struct ext4_extent_path *path,
 302                                             struct ext4_extent *ex, int *err,
 303                                             uint32_t flags)
 304 {
 305         ext4_fsblk_t goal, newblock;
 306
 307         goal = ext4_ext_find_goal(inode_ref, path, to_le32(ex->first_block));
 308         newblock = ext4_new_meta_blocks(inode_ref, goal, flags, NULL, err);
 309         return newblock;
 310 }
 311
 312 #if CONFIG_META_CSUM_ENABLE
 313 static uint32_t ext4_ext_block_csum(struct ext4_inode_ref *inode_ref,
 314                                     struct ext4_extent_header *eh)
 315 {
 316         uint32_t checksum = 0;
 317         struct ext4_sblock *sb = &inode_ref->fs->sb;
 318
 319         if (ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM)) {
 320                 uint32_t ino_index = to_le32(inode_ref->index);
 321                 uint32_t ino_gen =
 322                         to_le32(ext4_inode_get_generation(inode_ref->inode));
 323                 /* First calculate crc32 checksum against fs uuid */
 324                 checksum = ext4_crc32c(EXT4_CRC32_INIT, sb->uuid,
 325                                 sizeof(sb->uuid));
 326                 /* Then calculate crc32 checksum against inode number
 327                  * and inode generation */
 328                 checksum = ext4_crc32c(checksum, &ino_index,
 329                                      sizeof(ino_index));
 330                 checksum = ext4_crc32c(checksum, &ino_gen,
 331                                      sizeof(ino_gen));
 332                 /* Finally calculate crc32 checksum against
 333                  * the entire extent block up to the checksum field */
 334                 checksum = ext4_crc32c(checksum, eh,
 335                                 EXT4_EXTENT_TAIL_OFFSET(eh));
 336         }
 337         return checksum;
 338 }
 339 #else
 340 #define ext4_ext_block_csum(...) 0
 341 #endif
 342
 343 static void ext4_extent_block_csum_set(struct ext4_inode_ref *inode_ref __unused,
 344                                        struct ext4_extent_header *eh)
 345 {
 346         struct ext4_extent_tail *tail;
 347
 348         tail = find_ext4_extent_tail(eh);
 349         tail->et_checksum = to_le32(ext4_ext_block_csum(inode_ref, eh));
 350 }
 351
 352 static int ext4_ext_dirty(struct ext4_inode_ref *inode_ref,
 353                           struct ext4_extent_path *path)
 354 {
 355         if (path->block.lb_id)
 356                 path->block.dirty = true;
 357         else
 358                 inode_ref->dirty = true;
 359
 360         return EOK;
 361 }
 362
 363 static void ext4_ext_drop_refs(struct ext4_inode_ref *inode_ref,
 364                                struct ext4_extent_path *path, bool keep_other)
 365 {
 366         int32_t depth, i;
 367
 368         if (!path)
 369                 return;
 370         if (keep_other)
 371                 depth = 0;
 372         else
 373                 depth = path->depth;
 374
 375         for (i = 0; i <= depth; i++, path++) {
 376                 if (path->block.lb_id) {
 377                         if (path->block.dirty)
 378                                 ext4_extent_block_csum_set(inode_ref,
 379                                                 path->header);
 380
 381                         ext4_block_set(inode_ref->fs->bdev, &path->block);
 382                 }
 383         }
 384 }
 385
 386 /*
 387  * Check that whether the basic information inside the extent header
 388  * is correct or not.
 389  */
 390 static int ext4_ext_check(struct ext4_inode_ref *inode_ref,
 391                           struct ext4_extent_header *eh, uint16_t depth,
 392                           ext4_fsblk_t pblk __unused)
 393 {
 394         struct ext4_extent_tail *tail;
 395         const char *error_msg;
 396         (void)error_msg;
 397
 398         if (to_le16(eh->magic) != EXT4_EXTENT_MAGIC) {
 399                 error_msg = "invalid magic";
 400                 goto corrupted;
 401         }
 402         if (to_le16(eh->depth) != depth) {
 403                 error_msg = "unexpected eh_depth";
 404                 goto corrupted;
 405         }
 406         if (eh->max_entries_count == 0) {
 407                 error_msg = "invalid eh_max";
 408                 goto corrupted;
 409         }
 410         if (to_le16(eh->entries_count) > to_le16(eh->max_entries_count)) {
 411                 error_msg = "invalid eh_entries";
 412                 goto corrupted;
 413         }
 414
 415         tail = find_ext4_extent_tail(eh);
 416         struct ext4_sblock *sb = &inode_ref->fs->sb;
 417         if (ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM)) {
 418                 if (tail->et_checksum != to_le32(ext4_ext_block_csum(inode_ref, eh))) {
 419                         /* FIXME: Warning: extent checksum damaged? */
 420                 }
 421         }
 422
 423         return EOK;
 424
 425 corrupted:
 426         ext4_dbg(DEBUG_EXTENT, "Bad extents B+ tree block: %s. "
 427                                "Blocknr: %" PRId64 "\n",
 428                  error_msg, pblk);
 429         return EIO;
 430 }
 431
 432 static int read_extent_tree_block(struct ext4_inode_ref *inode_ref,
 433                                   ext4_fsblk_t pblk, int32_t depth,
 434                                   struct ext4_block *bh,
 435                                   uint32_t flags __unused)
 436 {
 437         int err;
 438
 439         err = ext4_block_get(inode_ref->fs->bdev, bh, pblk);
 440         if (err != EOK)
 441                 goto errout;
 442
 443         err = ext4_ext_check(inode_ref, ext_block_hdr(bh), depth, pblk);
 444         if (err != EOK)
 445                 goto errout;
 446
 447         return EOK;
 448 errout:
 449         if (bh->lb_id)
 450                 ext4_block_set(inode_ref->fs->bdev, bh);
 451
 452         return err;
 453 }
 454
 455 /*
 456  * ext4_ext_binsearch_idx:
 457  * binary search for the closest index of the given block
 458  * the header must be checked before calling this
 459  */
 460 static void ext4_ext_binsearch_idx(struct ext4_extent_path *path,
 461                                    ext4_lblk_t block)
 462 {
 463         struct ext4_extent_header *eh = path->header;
 464         struct ext4_extent_index *r, *l, *m;
 465
 466         l = EXT_FIRST_INDEX(eh) + 1;
 467         r = EXT_LAST_INDEX(eh);
 468         while (l <= r) {
 469                 m = l + (r - l) / 2;
 470                 if (block < to_le32(m->first_block))
 471                         r = m - 1;
 472                 else
 473                         l = m + 1;
 474         }
 475
 476         path->index = l - 1;
 477 }
 478
 479 /*
 480  * ext4_ext_binsearch:
 481  * binary search for closest extent of the given block
 482  * the header must be checked before calling this
 483  */
 484 static void ext4_ext_binsearch(struct ext4_extent_path *path, ext4_lblk_t block)
 485 {
 486         struct ext4_extent_header *eh = path->header;
 487         struct ext4_extent *r, *l, *m;
 488
 489         if (eh->entries_count == 0) {
 490                 /*
 491                  * this leaf is empty:
 492                  * we get such a leaf in split/add case
 493                  */
 494                 return;
 495         }
 496
 497         l = EXT_FIRST_EXTENT(eh) + 1;
 498         r = EXT_LAST_EXTENT(eh);
 499
 500         while (l <= r) {
 501                 m = l + (r - l) / 2;
 502                 if (block < to_le32(m->first_block))
 503                         r = m - 1;
 504                 else
 505                         l = m + 1;
 506         }
 507
 508         path->extent = l - 1;
 509 }
 510
 511 static int ext4_find_extent(struct ext4_inode_ref *inode_ref, ext4_lblk_t block,
 512                             struct ext4_extent_path **orig_path, uint32_t flags)
 513 {
 514         struct ext4_extent_header *eh;
 515         struct ext4_block bh = EXT4_BLOCK_ZERO();
 516         ext4_fsblk_t buf_block = 0;
 517         struct ext4_extent_path *path = *orig_path;
 518         int32_t depth, ppos = 0;
 519         int32_t i;
 520         int ret;
 521
 522         eh = ext_inode_hdr(inode_ref->inode);
 523         depth = ext_depth(inode_ref->inode);
 524
 525         if (path) {
 526                 ext4_ext_drop_refs(inode_ref, path, 0);
 527                 if (depth > path[0].maxdepth) {
 528                         free(path);
 529                         *orig_path = path = NULL;
 530                 }
 531         }
 532         if (!path) {
 533                 int32_t path_depth = depth + 1;
 534                 /* account possible depth increase */
 535                 path = calloc(1, sizeof(struct ext4_extent_path) *
 536                                      (path_depth + 1));
 537                 if (!path)
 538                         return ENOMEM;
 539                 path[0].maxdepth = path_depth;
 540         }
 541         path[0].header = eh;
 542         path[0].block = bh;
 543
 544         i = depth;
 545         /* walk through the tree */
 546         while (i) {
 547                 ext4_ext_binsearch_idx(path + ppos, block);
 548                 path[ppos].p_block = ext4_idx_pblock(path[ppos].index);
 549                 path[ppos].depth = i;
 550                 path[ppos].extent = NULL;
 551                 buf_block = path[ppos].p_block;
 552
 553                 i--;
 554                 ppos++;
 555                 if (!path[ppos].block.lb_id ||
 556                     path[ppos].block.lb_id != buf_block) {
 557                         ret = read_extent_tree_block(inode_ref, buf_block, i,
 558                                                      &bh, flags);
 559                         if (ret != EOK) {
 560                                 goto err;
 561                         }
 562                         if (ppos > depth) {
 563                                 ext4_block_set(inode_ref->fs->bdev, &bh);
 564                                 ret = EIO;
 565                                 goto err;
 566                         }
 567
 568                         eh = ext_block_hdr(&bh);
 569                         path[ppos].block = bh;
 570                         path[ppos].header = eh;
 571                 }
 572         }
 573
 574         path[ppos].depth = i;
 575         path[ppos].extent = NULL;
 576         path[ppos].index = NULL;
 577
 578         /* find extent */
 579         ext4_ext_binsearch(path + ppos, block);
 580         /* if not an empty leaf */
 581         if (path[ppos].extent)
 582                 path[ppos].p_block = ext4_ext_pblock(path[ppos].extent);
 583
 584         *orig_path = path;
 585
 586         ret = EOK;
 587         return ret;
 588
 589 err:
 590         ext4_ext_drop_refs(inode_ref, path, 0);
 591         free(path);
 592         if (orig_path)
 593                 *orig_path = NULL;
 594         return ret;
 595 }
 596
 597 static void ext4_ext_init_header(struct ext4_inode_ref *inode_ref,
 598                                  struct ext4_extent_header *eh, int32_t depth)
 599 {
 600         eh->entries_count = 0;
 601         eh->max_entries_count = to_le16(ext4_ext_max_entries(inode_ref, depth));
 602         eh->magic = to_le16(EXT4_EXTENT_MAGIC);
 603         eh->depth = depth;
 604 }
 605
 606 /*
 607  * Be cautious, the buffer_head returned is not yet mark dirtied. */
 608 static int ext4_ext_split_node(struct ext4_inode_ref *inode_ref,
 609                                struct ext4_extent_path *path, int32_t at,
 610                                struct ext4_extent *newext,
 611                                ext4_fsblk_t *sibling, struct ext4_block *new_bh)
 612 {
 613         int ret;
 614         ext4_fsblk_t newblock;
 615         struct ext4_block bh = EXT4_BLOCK_ZERO();
 616         int32_t depth = ext_depth(inode_ref->inode);
 617
 618         ext4_assert(sibling);
 619
 620         /* FIXME: currently we split at the point after the current extent. */
 621         newblock = ext4_ext_new_meta_block(inode_ref, path, newext, &ret, 0);
 622         if (ret)
 623                 goto cleanup;
 624
 625         /*  For write access.# */
 626         ret = ext4_block_get(inode_ref->fs->bdev, &bh, newblock);
 627         if (ret != EOK)
 628                 goto cleanup;
 629
 630         if (at == depth) {
 631                 /* start copy from next extent */
 632                 ptrdiff_t m = EXT_MAX_EXTENT(path[at].header) - path[at].extent;
 633                 struct ext4_extent_header *neh;
 634                 neh = ext_block_hdr(&bh);
 635                 ext4_ext_init_header(inode_ref, neh, 0);
 636                 if (m) {
 637                         struct ext4_extent *ex;
 638                         ex = EXT_FIRST_EXTENT(neh);
 639                         memmove(ex, path[at].extent + 1,
 640                                 sizeof(struct ext4_extent) * m);
 641                         neh->entries_count =
 642                             to_le16(to_le16(neh->entries_count) + m);
 643                         path[at].header->entries_count = to_le16(
 644                             to_le16(path[at].header->entries_count) - m);
 645                         ret = ext4_ext_dirty(inode_ref, path + at);
 646                         if (ret)
 647                                 goto cleanup;
 648                 }
 649         } else {
 650                 ptrdiff_t m = EXT_MAX_INDEX(path[at].header) - path[at].index;
 651                 struct ext4_extent_header *neh;
 652                 neh = ext_block_hdr(&bh);
 653                 ext4_ext_init_header(inode_ref, neh, depth - at);
 654                 if (m) {
 655                         struct ext4_extent_index *ix;
 656                         ix = EXT_FIRST_INDEX(neh);
 657                         memmove(ix, path[at].index + 1,
 658                                 sizeof(struct ext4_extent) * m);
 659                         neh->entries_count =
 660                             to_le16(to_le16(neh->entries_count) + m);
 661                         path[at].header->entries_count = to_le16(
 662                             to_le16(path[at].header->entries_count) - m);
 663                         ret = ext4_ext_dirty(inode_ref, path + at);
 664                         if (ret)
 665                                 goto cleanup;
 666                 }
 667         }
 668 cleanup:
 669         if (ret) {
 670                 if (bh.lb_id) {
 671                         ext4_block_set(inode_ref->fs->bdev, &bh);
 672                 }
 673                 if (newblock)
 674                         ext4_ext_free_blocks(inode_ref, newblock, 1, 0);
 675
 676                 newblock = 0;
 677         }
 678         *sibling = newblock;
 679         *new_bh = bh;
 680         return ret;
 681 }
 682
 683 static ext4_lblk_t ext4_ext_block_index(struct ext4_extent_header *eh)
 684 {
 685         if (eh->depth)
 686                 return to_le32(EXT_FIRST_INDEX(eh)->first_block);
 687
 688         return to_le32(EXT_FIRST_EXTENT(eh)->first_block);
 689 }
 690
 691 struct ext_split_trans {
 692         ext4_fsblk_t ptr;
 693         struct ext4_extent_path path;
 694         int switch_to;
 695 };
 696
 697 static int ext4_ext_insert_index(struct ext4_inode_ref *inode_ref,
 698                                  struct ext4_extent_path *path,
 699                                  int32_t at,
 700                                  struct ext4_extent *newext,
 701                                  ext4_lblk_t insert_index,
 702                                  ext4_fsblk_t insert_block,
 703                                  struct ext_split_trans *spt,
 704                                  bool *need_grow)
 705 {
 706         struct ext4_extent_index *ix;
 707         struct ext4_extent_path *curp = path + at;
 708         struct ext4_block bh = EXT4_BLOCK_ZERO();
 709         int32_t len;
 710         int err;
 711         struct ext4_extent_header *eh;
 712
 713         *need_grow = false;
 714
 715         if (curp->index && insert_index == to_le32(curp->index->first_block))
 716                 return EIO;
 717
 718         if (to_le16(curp->header->entries_count) ==
 719             to_le16(curp->header->max_entries_count)) {
 720                 if (at) {
 721                         struct ext4_extent_header *neh;
 722                         err = ext4_ext_split_node(inode_ref, path, at, newext,
 723                                                   &spt->ptr, &bh);
 724                         if (err != EOK)
 725                                 goto out;
 726
 727                         neh = ext_block_hdr(&bh);
 728                         if (insert_index > to_le32(curp->index->first_block)) {
 729                                 /* Make decision which node should be used to
 730                                  * insert the index.*/
 731                                 if (to_le16(neh->entries_count) >
 732                                     to_le16(curp->header->entries_count)) {
 733                                         eh = curp->header;
 734                                         /* insert after */
 735                                         ix = EXT_LAST_INDEX(eh) + 1;
 736                                 } else {
 737                                         eh = neh;
 738                                         ix = EXT_FIRST_INDEX(eh);
 739                                 }
 740                         } else {
 741                                 eh = curp->header;
 742                                 /* insert before */
 743                                 ix = EXT_LAST_INDEX(eh);
 744                         }
 745                 } else {
 746                         err = EOK;
 747                         *need_grow = true;
 748                         goto out;
 749                 }
 750         } else {
 751                 eh = curp->header;
 752                 if (curp->index == NULL) {
 753                         ix = EXT_FIRST_INDEX(eh);
 754                         curp->index = ix;
 755                 } else if (insert_index > to_le32(curp->index->first_block)) {
 756                         /* insert after */
 757                         ix = curp->index + 1;
 758                 } else {
 759                         /* insert before */
 760                         ix = curp->index;
 761                 }
 762         }
 763
 764         len = EXT_LAST_INDEX(eh) - ix + 1;
 765         ext4_assert(len >= 0);
 766         if (len > 0)
 767                 memmove(ix + 1, ix, len * sizeof(struct ext4_extent_index));
 768
 769         if (ix > EXT_MAX_INDEX(eh)) {
 770                 err = EIO;
 771                 goto out;
 772         }
 773
 774         ix->first_block = to_le32(insert_index);
 775         ext4_idx_store_pblock(ix, insert_block);
 776         eh->entries_count = to_le16(to_le16(eh->entries_count) + 1);
 777
 778         if (ix > EXT_LAST_INDEX(eh)) {
 779                 err = EIO;
 780                 goto out;
 781         }
 782
 783         if (eh == curp->header)
 784                 err = ext4_ext_dirty(inode_ref, curp);
 785         else
 786                 err = EOK;
 787
 788 out:
 789         if (err != EOK || *need_grow) {
 790                 if (bh.lb_id)
 791                         ext4_block_set(inode_ref->fs->bdev, &bh);
 792
 793                 spt->ptr = 0;
 794         } else if (bh.lb_id) {
 795                 /* If we got a sibling leaf. */
 796                 ext4_extent_block_csum_set(inode_ref, ext_block_hdr(&bh));
 797                 bh.dirty = true;
 798
 799                 spt->path.p_block = ext4_idx_pblock(ix);
 800                 spt->path.depth = to_le16(eh->depth);
 801                 spt->path.maxdepth = 0;
 802                 spt->path.extent = NULL;
 803                 spt->path.index = ix;
 804                 spt->path.header = eh;
 805                 spt->path.block = bh;
 806
 807                 /*
 808                  * If newext->ee_block can be included into the
 809                  * right sub-tree.
 810                  */
 811                 if (to_le32(newext->first_block) >=
 812                     ext4_ext_block_index(ext_block_hdr(&bh)))
 813                         spt->switch_to = 1;
 814                 else {
 815                         curp->index = ix;
 816                         curp->p_block = ext4_idx_pblock(ix);
 817                 }
 818
 819         } else {
 820                 spt->ptr = 0;
 821                 curp->index = ix;
 822                 curp->p_block = ext4_idx_pblock(ix);
 823         }
 824         return err;
 825 }
 826
 827 /*
 828  * ext4_ext_correct_indexes:
 829  * if leaf gets modified and modified extent is first in the leaf,
 830  * then we have to correct all indexes above.
 831  */
 832 static int ext4_ext_correct_indexes(struct ext4_inode_ref *inode_ref,
 833                                     struct ext4_extent_path *path)
 834 {
 835         struct ext4_extent_header *eh;
 836         int32_t depth = ext_depth(inode_ref->inode);
 837         struct ext4_extent *ex;
 838         uint32_t border;
 839         int32_t k;
 840         int err = EOK;
 841
 842         eh = path[depth].header;
 843         ex = path[depth].extent;
 844
 845         if (ex == NULL || eh == NULL) {
 846                 return EIO;
 847         }
 848
 849         if (depth == 0) {
 850                 /* there is no tree at all */
 851                 return EOK;
 852         }
 853
 854         if (ex != EXT_FIRST_EXTENT(eh)) {
 855                 /* we correct tree if first leaf got modified only */
 856                 return EOK;
 857         }
 858
 859         /*
 860          * TODO: we need correction if border is smaller than current one
 861          */
 862         k = depth - 1;
 863         border = path[depth].extent->first_block;
 864         path[k].index->first_block = border;
 865         err = ext4_ext_dirty(inode_ref, path + k);
 866         if (err != EOK)
 867                 return err;
 868
 869         while (k--) {
 870                 /* change all left-side indexes */
 871                 if (path[k + 1].index != EXT_FIRST_INDEX(path[k + 1].header))
 872                         break;
 873                 path[k].index->first_block = border;
 874                 err = ext4_ext_dirty(inode_ref, path + k);
 875                 if (err != EOK)
 876                         break;
 877         }
 878
 879         return err;
 880 }
 881
 882 static bool ext4_ext_can_prepend(struct ext4_extent *ex1,
 883                                  struct ext4_extent *ex2)
 884 {
 885         if (ext4_ext_pblock(ex2) + ext4_ext_get_actual_len(ex2) !=
 886             ext4_ext_pblock(ex1))
 887                 return false;
 888
 889 #ifdef AGGRESSIVE_TEST
 890         if (ext4_ext_get_actual_len(ex1) + ext4_ext_get_actual_len(ex2) > 4)
 891                 return 0;
 892 #else
 893         if (ext4_ext_is_unwritten(ex1)) {
 894                 if (ext4_ext_get_actual_len(ex1) +
 895                         ext4_ext_get_actual_len(ex2) >
 896                     EXT_UNWRITTEN_MAX_LEN)
 897                         return false;
 898         } else if (ext4_ext_get_actual_len(ex1) + ext4_ext_get_actual_len(ex2) >
 899                    EXT_INIT_MAX_LEN)
 900                 return false;
 901 #endif
 902
 903         if (to_le32(ex2->first_block) + ext4_ext_get_actual_len(ex2) !=
 904             to_le32(ex1->first_block))
 905                 return false;
 906
 907         return true;
 908 }
 909
 910 static bool ext4_ext_can_append(struct ext4_extent *ex1,
 911                                 struct ext4_extent *ex2)
 912 {
 913         if (ext4_ext_pblock(ex1) + ext4_ext_get_actual_len(ex1) !=
 914             ext4_ext_pblock(ex2))
 915                 return false;
 916
 917 #ifdef AGGRESSIVE_TEST
 918         if (ext4_ext_get_actual_len(ex1) + ext4_ext_get_actual_len(ex2) > 4)
 919                 return 0;
 920 #else
 921         if (ext4_ext_is_unwritten(ex1)) {
 922                 if (ext4_ext_get_actual_len(ex1) +
 923                         ext4_ext_get_actual_len(ex2) >
 924                     EXT_UNWRITTEN_MAX_LEN)
 925                         return false;
 926         } else if (ext4_ext_get_actual_len(ex1) + ext4_ext_get_actual_len(ex2) >
 927                    EXT_INIT_MAX_LEN)
 928                 return false;
 929 #endif
 930
 931         if (to_le32(ex1->first_block) + ext4_ext_get_actual_len(ex1) !=
 932             to_le32(ex2->first_block))
 933                 return false;
 934
 935         return true;
 936 }
 937
 938 static int ext4_ext_insert_leaf(struct ext4_inode_ref *inode_ref,
 939                                 struct ext4_extent_path *path,
 940                                 int32_t at,
 941                                 struct ext4_extent *newext,
 942                                 struct ext_split_trans *spt,
 943                                 uint32_t flags,
 944                                 bool *need_grow)
 945 {
 946         struct ext4_extent_path *curp = path + at;
 947         struct ext4_extent *ex = curp->extent;
 948         struct ext4_block bh = EXT4_BLOCK_ZERO();
 949         int32_t len;
 950         int err = EOK;
 951         int unwritten;
 952         struct ext4_extent_header *eh = NULL;
 953
 954         *need_grow = false;
 955
 956         if (curp->extent &&
 957             to_le32(newext->first_block) == to_le32(curp->extent->first_block))
 958                 return EIO;
 959
 960         if (!(flags & EXT4_EXT_NO_COMBINE)) {
 961                 if (curp->extent && ext4_ext_can_append(curp->extent, newext)) {
 962                         unwritten = ext4_ext_is_unwritten(curp->extent);
 963                         curp->extent->block_count =
 964                             to_le16(ext4_ext_get_actual_len(curp->extent) +
 965                                     ext4_ext_get_actual_len(newext));
 966                         if (unwritten)
 967                                 ext4_ext_mark_unwritten(curp->extent);
 968                         err = ext4_ext_dirty(inode_ref, curp);
 969                         goto out;
 970                 }
 971
 972                 if (curp->extent &&
 973                     ext4_ext_can_prepend(curp->extent, newext)) {
 974                         unwritten = ext4_ext_is_unwritten(curp->extent);
 975                         curp->extent->first_block = newext->first_block;
 976                         curp->extent->block_count =
 977                             to_le16(ext4_ext_get_actual_len(curp->extent) +
 978                                     ext4_ext_get_actual_len(newext));
 979                         if (unwritten)
 980                                 ext4_ext_mark_unwritten(curp->extent);
 981                         err = ext4_ext_dirty(inode_ref, curp);
 982                         goto out;
 983                 }
 984         }
 985
 986         if (to_le16(curp->header->entries_count) ==
 987             to_le16(curp->header->max_entries_count)) {
 988                 if (at) {
 989                         struct ext4_extent_header *neh;
 990                         err = ext4_ext_split_node(inode_ref, path, at, newext,
 991                                                   &spt->ptr, &bh);
 992                         if (err != EOK)
 993                                 goto out;
 994
 995                         neh = ext_block_hdr(&bh);
 996                         if (to_le32(newext->first_block) >
 997                             to_le32(curp->extent->first_block)) {
 998                                 if (to_le16(neh->entries_count) >
 999                                     to_le16(curp->header->entries_count)) {
1000                                         eh = curp->header;
1001                                         /* insert after */
1002                                         ex = EXT_LAST_EXTENT(eh) + 1;
1003                                 } else {
1004                                         eh = neh;
1005                                         ex = EXT_FIRST_EXTENT(eh);
1006                                 }
1007                         } else {
1008                                 eh = curp->header;
1009                                 /* insert before */
1010                                 ex = EXT_LAST_EXTENT(eh);
1011                         }
1012                 } else {
1013                         err = EOK;
1014                         *need_grow = true;
1015                         goto out;
1016                 }
1017         } else {
1018                 eh = curp->header;
1019                 if (curp->extent == NULL) {
1020                         ex = EXT_FIRST_EXTENT(eh);
1021                         curp->extent = ex;
1022                 } else if (to_le32(newext->first_block) >
1023                            to_le32(curp->extent->first_block)) {
1024                         /* insert after */
1025                         ex = curp->extent + 1;
1026                 } else {
1027                         /* insert before */
1028                         ex = curp->extent;
1029                 }
1030         }
1031
1032         len = EXT_LAST_EXTENT(eh) - ex + 1;
1033         ext4_assert(len >= 0);
1034         if (len > 0)
1035                 memmove(ex + 1, ex, len * sizeof(struct ext4_extent));
1036
1037         if (ex > EXT_MAX_EXTENT(eh)) {
1038                 err = EIO;
1039                 goto out;
1040         }
1041
1042         ex->first_block = newext->first_block;
1043         ex->block_count = newext->block_count;
1044         ext4_ext_store_pblock(ex, ext4_ext_pblock(newext));
1045         eh->entries_count = to_le16(to_le16(eh->entries_count) + 1);
1046
1047         if (ex > EXT_LAST_EXTENT(eh)) {
1048                 err = EIO;
1049                 goto out;
1050         }
1051
1052         if (eh == curp->header) {
1053                 err = ext4_ext_correct_indexes(inode_ref, path);
1054                 if (err != EOK)
1055                         goto out;
1056                 err = ext4_ext_dirty(inode_ref, curp);
1057         } else
1058                 err = EOK;
1059
1060 out:
1061         if (err != EOK || *need_grow) {
1062                 if (bh.lb_id)
1063                         ext4_block_set(inode_ref->fs->bdev, &bh);
1064
1065                 spt->ptr = 0;
1066         } else if (bh.lb_id) {
1067                 /* If we got a sibling leaf. */
1068                 ext4_extent_block_csum_set(inode_ref, ext_block_hdr(&bh));
1069                 bh.dirty = true;
1070
1071                 spt->path.p_block = ext4_ext_pblock(ex);
1072                 spt->path.depth = to_le16(eh->depth);
1073                 spt->path.maxdepth = 0;
1074                 spt->path.extent = ex;
1075                 spt->path.index = NULL;
1076                 spt->path.header = eh;
1077                 spt->path.block = bh;
1078
1079                 /*
1080                  * If newext->ee_block can be included into the
1081                  * right sub-tree.
1082                  */
1083                 if (to_le32(newext->first_block) >=
1084                     ext4_ext_block_index(ext_block_hdr(&bh)))
1085                         spt->switch_to = 1;
1086                 else {
1087                         curp->extent = ex;
1088                         curp->p_block = ext4_ext_pblock(ex);
1089                 }
1090
1091         } else {
1092                 spt->ptr = 0;
1093                 curp->extent = ex;
1094                 curp->p_block = ext4_ext_pblock(ex);
1095         }
1096
1097         return err;
1098 }
1099
1100 /*
1101  * ext4_ext_grow_indepth:
1102  * implements tree growing procedure:
1103  * - allocates new block
1104  * - moves top-level data (index block or leaf) into the new block
1105  * - initializes new top-level, creating index that points to the
1106  *   just created block
1107  */
1108 static int ext4_ext_grow_indepth(struct ext4_inode_ref *inode_ref,
1109                                  uint32_t flags)
1110 {
1111         struct ext4_extent_header *neh;
1112         struct ext4_block bh = EXT4_BLOCK_ZERO();
1113         ext4_fsblk_t newblock, goal = 0;
1114         int err = EOK;
1115
1116         /* Try to prepend new index to old one */
1117         if (ext_depth(inode_ref->inode))
1118                 goal = ext4_idx_pblock(
1119                     EXT_FIRST_INDEX(ext_inode_hdr(inode_ref->inode)));
1120         else
1121                 goal = ext4_fs_inode_to_goal_block(inode_ref);
1122
1123         newblock = ext4_new_meta_blocks(inode_ref, goal, flags, NULL, &err);
1124         if (newblock == 0)
1125                 return err;
1126
1127         /* # */
1128         err = ext4_block_get(inode_ref->fs->bdev, &bh, newblock);
1129         if (err != EOK) {
1130                 ext4_ext_free_blocks(inode_ref, newblock, 1, 0);
1131                 return err;
1132         }
1133
1134         /* move top-level index/leaf into new block */
1135         memmove(bh.data, inode_ref->inode->blocks,
1136                 sizeof(inode_ref->inode->blocks));
1137
1138         /* set size of new block */
1139         neh = ext_block_hdr(&bh);
1140         /* old root could have indexes or leaves
1141          * so calculate e_max right way */
1142         if (ext_depth(inode_ref->inode))
1143                 neh->max_entries_count =
1144                     to_le16(ext4_ext_space_block_idx(inode_ref));
1145         else
1146                 neh->max_entries_count =
1147                     to_le16(ext4_ext_space_block(inode_ref));
1148
1149         neh->magic = to_le16(EXT4_EXTENT_MAGIC);
1150
1151         /* Update top-level index: num,max,pointer */
1152         neh = ext_inode_hdr(inode_ref->inode);
1153         neh->entries_count = to_le16(1);
1154         ext4_idx_store_pblock(EXT_FIRST_INDEX(neh), newblock);
1155         if (neh->depth == 0) {
1156                 /* Root extent block becomes index block */
1157                 neh->max_entries_count =
1158                     to_le16(ext4_ext_space_root_idx(inode_ref));
1159                 EXT_FIRST_INDEX(neh)
1160                     ->first_block = EXT_FIRST_EXTENT(neh)->first_block;
1161         }
1162         neh->depth = to_le16(to_le16(neh->depth) + 1);
1163
1164         ext4_extent_block_csum_set(inode_ref, neh);
1165         bh.dirty = true;
1166         inode_ref->dirty = true;
1167         ext4_block_set(inode_ref->fs->bdev, &bh);
1168
1169         return err;
1170 }
1171
1172 __unused static void print_path(struct ext4_extent_path *path)
1173 {
1174         int32_t i = path->depth;
1175         while (i >= 0) {
1176
1177                 ptrdiff_t a =
1178                     (path->extent)
1179                         ? (path->extent - EXT_FIRST_EXTENT(path->header))
1180                         : 0;
1181                 ptrdiff_t b =
1182                     (path->index)
1183                         ? (path->index - EXT_FIRST_INDEX(path->header))
1184                         : 0;
1185
1186                 (void)a;
1187                 (void)b;
1188                 ext4_dbg(DEBUG_EXTENT,
1189                          "depth %" PRId32 ", p_block: %" PRIu64 ","
1190                          "p_ext offset: %td, p_idx offset: %td\n",
1191                          i, path->p_block, a, b);
1192                 i--;
1193                 path++;
1194         }
1195 }
1196
1197 static void ext4_ext_replace_path(struct ext4_inode_ref *inode_ref,
1198                                   struct ext4_extent_path *path,
1199                                   struct ext_split_trans *spt,
1200                                   int32_t level)
1201 {
1202         int32_t depth = ext_depth(inode_ref->inode);
1203         int32_t i = depth - level;
1204         ext4_ext_drop_refs(inode_ref, path + i, 1);
1205         path[i] = spt[level].path;
1206 }
1207
1208 static int ext4_ext_insert_extent(struct ext4_inode_ref *inode_ref,
1209                                   struct ext4_extent_path **ppath,
1210                                   struct ext4_extent *newext, uint32_t flags)
1211 {
1212         int32_t i, depth, level;
1213         int ret = EOK;
1214         ext4_fsblk_t ptr = 0;
1215         bool need_grow = false;
1216         struct ext4_extent_path *path = *ppath;
1217         struct ext_split_trans *spt = NULL;
1218         struct ext_split_trans newblock;
1219
1220         memset(&newblock, 0, sizeof(newblock));
1221
1222         depth = ext_depth(inode_ref->inode);
1223         for (i = depth, level = 0; i >= 0; i--, level++)
1224                 if (EXT_HAS_FREE_INDEX(path + i))
1225                         break;
1226
1227         if (level) {
1228                 spt = calloc(1, sizeof(struct ext_split_trans) * (level));
1229                 if (!spt) {
1230                         ret = ENOMEM;
1231                         goto out;
1232                 }
1233         }
1234         i = 0;
1235 again:
1236         depth = ext_depth(inode_ref->inode);
1237
1238         do {
1239                 if (!i) {
1240                         ret = ext4_ext_insert_leaf(inode_ref, path, depth - i,
1241                                                    newext, &newblock, flags,
1242                                                    &need_grow);
1243                 } else {
1244                         ret = ext4_ext_insert_index(
1245                             inode_ref, path, depth - i, newext,
1246                             ext4_ext_block_index(
1247                                 ext_block_hdr(&spt[i - 1].path.block)),
1248                             spt[i - 1].ptr, &newblock,
1249                             &need_grow);
1250                 }
1251                 ptr = newblock.ptr;
1252
1253                 if (ret != EOK)
1254                         goto out;
1255
1256                 else if (spt && ptr && !ret) {
1257                         /* Prepare for the next iteration after splitting. */
1258                         spt[i] = newblock;
1259                 }
1260
1261                 i++;
1262         } while (ptr != 0 && i <= depth);
1263
1264         if (need_grow) {
1265                 ret = ext4_ext_grow_indepth(inode_ref, 0);
1266                 if (ret)
1267                         goto out;
1268                 ret = ext4_find_extent(inode_ref, to_le32(newext->first_block),
1269                                        ppath, 0);
1270                 if (ret)
1271                         goto out;
1272                 i = depth;
1273                 path = *ppath;
1274                 goto again;
1275         }
1276 out:
1277         if (ret) {
1278                 if (path)
1279                         ext4_ext_drop_refs(inode_ref, path, 0);
1280
1281                 while (--level >= 0 && spt) {
1282                         if (spt[level].ptr) {
1283                                 ext4_ext_free_blocks(inode_ref, spt[level].ptr,
1284                                                      1, 0);
1285                                 ext4_ext_drop_refs(inode_ref, &spt[level].path,
1286                                                    1);
1287                         }
1288                 }
1289         } else {
1290                 while (--level >= 0 && spt) {
1291                         if (spt[level].switch_to)
1292                                 ext4_ext_replace_path(inode_ref, path, spt,
1293                                                       level);
1294                         else if (spt[level].ptr)
1295                                 ext4_ext_drop_refs(inode_ref, &spt[level].path,
1296                                                    1);
1297                 }
1298         }
1299         if (spt)
1300                 free(spt);
1301
1302         return ret;
1303 }
1304
1305 static void ext4_ext_remove_blocks(struct ext4_inode_ref *inode_ref,
1306                                    struct ext4_extent *ex, ext4_lblk_t from,
1307                                    ext4_lblk_t to)
1308 {
1309         ext4_lblk_t len = to - from + 1;
1310         ext4_lblk_t num;
1311         ext4_fsblk_t start;
1312         num = from - to_le32(ex->first_block);
1313         start = ext4_ext_pblock(ex) + num;
1314         ext4_dbg(DEBUG_EXTENT,
1315                  "Freeing %" PRIu32 " at %" PRIu64 ", %" PRIu32 "\n", from,
1316                  start, len);
1317
1318         ext4_ext_free_blocks(inode_ref, start, len, 0);
1319 }
1320
1321 static int ext4_ext_remove_idx(struct ext4_inode_ref *inode_ref,
1322                                struct ext4_extent_path *path, int32_t depth)
1323 {
1324         int err = EOK;
1325         int32_t i = depth;
1326         ext4_fsblk_t leaf;
1327
1328         /* free index block */
1329         leaf = ext4_idx_pblock(path[i].index);
1330
1331         if (path[i].index != EXT_LAST_INDEX(path[i].header)) {
1332                 ptrdiff_t len = EXT_LAST_INDEX(path[i].header) - path[i].index;
1333                 memmove(path[i].index, path[i].index + 1,
1334                         len * sizeof(struct ext4_extent_index));
1335         }
1336
1337         path[i].header->entries_count =
1338             to_le16(to_le16(path[i].header->entries_count) - 1);
1339         err = ext4_ext_dirty(inode_ref, path + i);
1340         if (err != EOK)
1341                 return err;
1342
1343         ext4_dbg(DEBUG_EXTENT, "IDX: Freeing %" PRIu32 " at %" PRIu64 ", %d\n",
1344                  to_le32(path[i].index->first_block), leaf, 1);
1345         ext4_ext_free_blocks(inode_ref, leaf, 1, 0);
1346
1347         while (i > 0) {
1348                 if (path[i].index != EXT_FIRST_INDEX(path[i].header))
1349                         break;
1350
1351                 path[i - 1].index->first_block = path[i].index->first_block;
1352                 err = ext4_ext_dirty(inode_ref, path + i - 1);
1353                 if (err != EOK)
1354                         break;
1355
1356                 i--;
1357         }
1358         return err;
1359 }
1360
1361 static int ext4_ext_remove_leaf(struct ext4_inode_ref *inode_ref,
1362                                 struct ext4_extent_path *path, ext4_lblk_t from,
1363                                 ext4_lblk_t to)
1364 {
1365
1366         int32_t depth = ext_depth(inode_ref->inode);
1367         struct ext4_extent *ex = path[depth].extent;
1368         struct ext4_extent *start_ex, *ex2 = NULL;
1369         struct ext4_extent_header *eh = path[depth].header;
1370         int32_t len;
1371         int err = EOK;
1372         uint16_t new_entries;
1373
1374         start_ex = ex;
1375         new_entries = to_le16(eh->entries_count);
1376         while (ex <= EXT_LAST_EXTENT(path[depth].header) &&
1377                to_le32(ex->first_block) <= to) {
1378                 int32_t new_len = 0;
1379                 int unwritten;
1380                 ext4_lblk_t start, new_start;
1381                 ext4_fsblk_t newblock;
1382                 new_start = start = to_le32(ex->first_block);
1383                 len = ext4_ext_get_actual_len(ex);
1384                 newblock = ext4_ext_pblock(ex);
1385                 if (start < from) {
1386                         len -= from - start;
1387                         new_len = from - start;
1388                         start = from;
1389                         start_ex++;
1390                 } else {
1391                         if (start + len - 1 > to) {
1392                                 len -= start + len - 1 - to;
1393                                 new_len = start + len - 1 - to;
1394                                 new_start = to + 1;
1395                                 newblock += to + 1 - start;
1396                                 ex2 = ex;
1397                         }
1398                 }
1399
1400                 ext4_ext_remove_blocks(inode_ref, ex, start, start + len - 1);
1401                 ex->first_block = to_le32(new_start);
1402                 if (!new_len)
1403                         new_entries--;
1404                 else {
1405                         unwritten = ext4_ext_is_unwritten(ex);
1406                         ex->block_count = to_le16(new_len);
1407                         ext4_ext_store_pblock(ex, newblock);
1408                         if (unwritten)
1409                                 ext4_ext_mark_unwritten(ex);
1410                 }
1411
1412                 ex += 1;
1413         }
1414
1415         if (ex2 == NULL)
1416                 ex2 = ex;
1417
1418         if (ex2 <= EXT_LAST_EXTENT(eh))
1419                 memmove(start_ex, ex2, EXT_LAST_EXTENT(eh) - ex2 + 1);
1420
1421         eh->entries_count = to_le16(new_entries);
1422         ext4_ext_dirty(inode_ref, path + depth);
1423         if (path[depth].extent == EXT_FIRST_EXTENT(eh) && eh->entries_count)
1424                 err = ext4_ext_correct_indexes(inode_ref, path);
1425
1426         /* if this leaf is free, then we should
1427          * remove it from index block above */
1428         if (err == EOK && eh->entries_count == 0 && path[depth].block.lb_id)
1429                 err = ext4_ext_remove_idx(inode_ref, path, depth - 1);
1430         else if (depth > 0)
1431                 path[depth - 1].index++;
1432
1433         return err;
1434 }
1435
1436 static bool ext4_ext_more_to_rm(struct ext4_extent_path *path, ext4_lblk_t to)
1437 {
1438         if (!to_le16(path->header->entries_count))
1439                 return false;
1440
1441         if (path->index > EXT_LAST_INDEX(path->header))
1442                 return false;
1443
1444         if (to_le32(path->index->first_block) > to)
1445                 return false;
1446
1447         return true;
1448 }
1449
1450 int ext4_extent_remove_space(struct ext4_inode_ref *inode_ref, ext4_lblk_t from,
1451                           ext4_lblk_t to)
1452 {
1453         struct ext4_extent_path *path = NULL;
1454         int ret = EOK;
1455         int32_t depth = ext_depth(inode_ref->inode);
1456         int32_t i;
1457
1458         ret = ext4_find_extent(inode_ref, from, &path, 0);
1459         if (ret)
1460                 goto out;
1461
1462         if (!path[depth].extent) {
1463                 ret = EOK;
1464                 goto out;
1465         }
1466
1467         bool in_range = IN_RANGE(from, to_le32(path[depth].extent->first_block),
1468                         ext4_ext_get_actual_len(path[depth].extent));
1469
1470         if (!in_range) {
1471                 ret = EOK;
1472                 goto out;
1473         }
1474
1475         /* If we do remove_space inside the range of an extent */
1476         if ((to_le32(path[depth].extent->first_block) < from) &&
1477             (to < to_le32(path[depth].extent->first_block) +
1478                         ext4_ext_get_actual_len(path[depth].extent) - 1)) {
1479
1480                 struct ext4_extent *ex = path[depth].extent, newex;
1481                 int unwritten = ext4_ext_is_unwritten(ex);
1482                 ext4_lblk_t ee_block = to_le32(ex->first_block);
1483                 int32_t len = ext4_ext_get_actual_len(ex);
1484                 ext4_fsblk_t newblock =
1485                         to + 1 - ee_block + ext4_ext_pblock(ex);
1486
1487                 ex->block_count = to_le16(from - ee_block);
1488                 if (unwritten)
1489                         ext4_ext_mark_unwritten(ex);
1490
1491                 ext4_ext_dirty(inode_ref, path + depth);
1492
1493                 newex.first_block = to_le32(to + 1);
1494                 newex.block_count = to_le16(ee_block + len - 1 - to);
1495                 ext4_ext_store_pblock(&newex, newblock);
1496                 if (unwritten)
1497                         ext4_ext_mark_unwritten(&newex);
1498
1499                 ret = ext4_ext_insert_extent(inode_ref, &path, &newex, 0);
1500                 goto out;
1501         }
1502
1503         i = depth;
1504         while (i >= 0) {
1505                 if (i == depth) {
1506                         struct ext4_extent_header *eh;
1507                         struct ext4_extent *first_ex, *last_ex;
1508                         ext4_lblk_t leaf_from, leaf_to;
1509                         eh = path[i].header;
1510                         ext4_assert(to_le16(eh->entries_count) > 0);
1511                         first_ex = EXT_FIRST_EXTENT(eh);
1512                         last_ex = EXT_LAST_EXTENT(eh);
1513                         leaf_from = to_le32(first_ex->first_block);
1514                         leaf_to = to_le32(last_ex->first_block) +
1515                                   ext4_ext_get_actual_len(last_ex) - 1;
1516                         if (leaf_from < from)
1517                                 leaf_from = from;
1518
1519                         if (leaf_to > to)
1520                                 leaf_to = to;
1521
1522                         ext4_ext_remove_leaf(inode_ref, path, leaf_from,
1523                                         leaf_to);
1524                         ext4_ext_drop_refs(inode_ref, path + i, 0);
1525                         i--;
1526                         continue;
1527                 }
1528
1529                 struct ext4_extent_header *eh;
1530                 eh = path[i].header;
1531                 if (ext4_ext_more_to_rm(path + i, to)) {
1532                         struct ext4_block bh = EXT4_BLOCK_ZERO();
1533                         if (path[i + 1].block.lb_id)
1534                                 ext4_ext_drop_refs(inode_ref, path + i + 1, 0);
1535
1536                         ret = read_extent_tree_block(inode_ref,
1537                                         ext4_idx_pblock(path[i].index),
1538                                         depth - i - 1, &bh, 0);
1539                         if (ret)
1540                                 goto out;
1541
1542                         path[i].p_block =
1543                                         ext4_idx_pblock(path[i].index);
1544                         path[i + 1].block = bh;
1545                         path[i + 1].header = ext_block_hdr(&bh);
1546                         path[i + 1].depth = depth - i - 1;
1547                         if (i + 1 == depth)
1548                                 path[i + 1].extent = EXT_FIRST_EXTENT(
1549                                         path[i + 1].header);
1550                         else
1551                                 path[i + 1].index =
1552                                         EXT_FIRST_INDEX(path[i + 1].header);
1553
1554                         i++;
1555                 } else {
1556                         if (i > 0) {
1557                                 if (!eh->entries_count)
1558                                         ret = ext4_ext_remove_idx(inode_ref, path,
1559                                                         i - 1);
1560                                 else
1561                                         path[i - 1].index++;
1562
1563                         }
1564
1565                         if (i)
1566                                 ext4_block_set(inode_ref->fs->bdev,
1567                                                 &path[i].block);
1568
1569
1570                         i--;
1571                 }
1572
1573         }
1574
1575         /* TODO: flexible tree reduction should be here */
1576         if (path->header->entries_count == 0) {
1577                 /*
1578                  * truncate to zero freed all the tree,
1579                  * so we need to correct eh_depth
1580                  */
1581                 ext_inode_hdr(inode_ref->inode)->depth = 0;
1582                 ext_inode_hdr(inode_ref->inode)->max_entries_count =
1583                     to_le16(ext4_ext_space_root(inode_ref));
1584                 ret = ext4_ext_dirty(inode_ref, path);
1585         }
1586
1587 out:
1588         ext4_ext_drop_refs(inode_ref, path, 0);
1589         free(path);
1590         path = NULL;
1591         return ret;
1592 }
1593
1594 static int ext4_ext_split_extent_at(struct ext4_inode_ref *inode_ref,
1595                                     struct ext4_extent_path **ppath,
1596                                     ext4_lblk_t split, uint32_t split_flag)
1597 {
1598         struct ext4_extent *ex, newex;
1599         ext4_fsblk_t newblock;
1600         ext4_lblk_t ee_block;
1601         int32_t ee_len;
1602         int32_t depth = ext_depth(inode_ref->inode);
1603         int err = EOK;
1604
1605         ex = (*ppath)[depth].extent;
1606         ee_block = to_le32(ex->first_block);
1607         ee_len = ext4_ext_get_actual_len(ex);
1608         newblock = split - ee_block + ext4_ext_pblock(ex);
1609
1610         if (split == ee_block) {
1611                 /*
1612                  * case b: block @split is the block that the extent begins with
1613                  * then we just change the state of the extent, and splitting
1614                  * is not needed.
1615                  */
1616                 if (split_flag & EXT4_EXT_MARK_UNWRIT2)
1617                         ext4_ext_mark_unwritten(ex);
1618                 else
1619                         ext4_ext_mark_initialized(ex);
1620
1621                 err = ext4_ext_dirty(inode_ref, *ppath + depth);
1622                 goto out;
1623         }
1624
1625         ex->block_count = to_le16(split - ee_block);
1626         if (split_flag & EXT4_EXT_MARK_UNWRIT1)
1627                 ext4_ext_mark_unwritten(ex);
1628
1629         err = ext4_ext_dirty(inode_ref, *ppath + depth);
1630         if (err != EOK)
1631                 goto out;
1632
1633         newex.first_block = to_le32(split);
1634         newex.block_count = to_le16(ee_len - (split - ee_block));
1635         ext4_ext_store_pblock(&newex, newblock);
1636         if (split_flag & EXT4_EXT_MARK_UNWRIT2)
1637                 ext4_ext_mark_unwritten(&newex);
1638         err = ext4_ext_insert_extent(inode_ref, ppath, &newex,
1639                                      EXT4_EXT_NO_COMBINE);
1640         if (err != EOK)
1641                 goto restore_extent_len;
1642
1643 out:
1644         return err;
1645 restore_extent_len:
1646         ex->block_count = to_le16(ee_len);
1647         err = ext4_ext_dirty(inode_ref, *ppath + depth);
1648         return err;
1649 }
1650
1651 static int ext4_ext_convert_to_initialized(struct ext4_inode_ref *inode_ref,
1652                                            struct ext4_extent_path **ppath,
1653                                            ext4_lblk_t split, uint32_t blocks)
1654 {
1655         int32_t depth = ext_depth(inode_ref->inode), err = EOK;
1656         struct ext4_extent *ex = (*ppath)[depth].extent;
1657
1658         ext4_assert(to_le32(ex->first_block) <= split);
1659
1660         if (split + blocks ==
1661             to_le32(ex->first_block) + ext4_ext_get_actual_len(ex)) {
1662                 /* split and initialize right part */
1663                 err = ext4_ext_split_extent_at(inode_ref, ppath, split,
1664                                                EXT4_EXT_MARK_UNWRIT1);
1665         } else if (to_le32(ex->first_block) == split) {
1666                 /* split and initialize left part */
1667                 err = ext4_ext_split_extent_at(inode_ref, ppath, split + blocks,
1668                                                EXT4_EXT_MARK_UNWRIT2);
1669         } else {
1670                 /* split 1 extent to 3 and initialize the 2nd */
1671                 err = ext4_ext_split_extent_at(inode_ref, ppath, split + blocks,
1672                                                EXT4_EXT_MARK_UNWRIT1 |
1673                                                    EXT4_EXT_MARK_UNWRIT2);
1674                 if (!err) {
1675                         err = ext4_ext_split_extent_at(inode_ref, ppath, split,
1676                                                        EXT4_EXT_MARK_UNWRIT1);
1677                 }
1678         }
1679
1680         return err;
1681 }
1682
1683 static ext4_lblk_t ext4_ext_next_allocated_block(struct ext4_extent_path *path)
1684 {
1685         int32_t depth;
1686
1687         depth = path->depth;
1688
1689         if (depth == 0 && path->extent == NULL)
1690                 return EXT_MAX_BLOCKS;
1691
1692         while (depth >= 0) {
1693                 if (depth == path->depth) {
1694                         /* leaf */
1695                         if (path[depth].extent &&
1696                             path[depth].extent !=
1697                                 EXT_LAST_EXTENT(path[depth].header))
1698                                 return to_le32(
1699                                     path[depth].extent[1].first_block);
1700                 } else {
1701                         /* index */
1702                         if (path[depth].index !=
1703                             EXT_LAST_INDEX(path[depth].header))
1704                                 return to_le32(
1705                                     path[depth].index[1].first_block);
1706                 }
1707                 depth--;
1708         }
1709
1710         return EXT_MAX_BLOCKS;
1711 }
1712
1713 static int ext4_ext_zero_unwritten_range(struct ext4_inode_ref *inode_ref,
1714                                          ext4_fsblk_t block,
1715                                          uint32_t blocks_count)
1716 {
1717         int err = EOK;
1718         uint32_t i;
1719         uint32_t block_size = ext4_sb_get_block_size(&inode_ref->fs->sb);
1720         for (i = 0; i < blocks_count; i++) {
1721                 struct ext4_block bh = EXT4_BLOCK_ZERO();
1722                 err = ext4_block_get(inode_ref->fs->bdev, &bh, block + i);
1723                 if (err != EOK)
1724                         break;
1725
1726                 memset(bh.data, 0, block_size);
1727                 bh.dirty = true;
1728                 err = ext4_block_set(inode_ref->fs->bdev, &bh);
1729                 if (err != EOK)
1730                         break;
1731         }
1732         return err;
1733 }
1734
1735 int ext4_extent_get_blocks(struct ext4_inode_ref *inode_ref, ext4_fsblk_t iblock,
1736                         uint32_t max_blocks, ext4_fsblk_t *result, bool create,
1737                         uint32_t *blocks_count)
1738 {
1739         struct ext4_extent_path *path = NULL;
1740         struct ext4_extent newex, *ex;
1741         ext4_fsblk_t goal;
1742         int err = EOK;
1743         int32_t depth;
1744         uint32_t allocated = 0;
1745         ext4_fsblk_t next, newblock;
1746
1747         if (result)
1748                 *result = 0;
1749
1750         if (blocks_count)
1751                 *blocks_count = 0;
1752
1753         /* find extent for this block */
1754         err = ext4_find_extent(inode_ref, iblock, &path, 0);
1755         if (err != EOK) {
1756                 path = NULL;
1757                 goto out2;
1758         }
1759
1760         depth = ext_depth(inode_ref->inode);
1761
1762         /*
1763          * consistent leaf must not be empty
1764          * this situations is possible, though, _during_ tree modification
1765          * this is why assert can't be put in ext4_ext_find_extent()
1766          */
1767         ex = path[depth].extent;
1768         if (ex) {
1769                 ext4_lblk_t ee_block = to_le32(ex->first_block);
1770                 ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
1771                 uint16_t ee_len = ext4_ext_get_actual_len(ex);
1772                 /* if found exent covers block, simple return it */
1773                 if (IN_RANGE(iblock, ee_block, ee_len)) {
1774                         /* number of remain blocks in the extent */
1775                         allocated = ee_len - (iblock - ee_block);
1776
1777                         if (!ext4_ext_is_unwritten(ex)) {
1778                                 newblock = iblock - ee_block + ee_start;
1779                                 goto out;
1780                         }
1781
1782                         if (!create) {
1783                                 newblock = 0;
1784                                 goto out;
1785                         }
1786
1787                         uint32_t zero_range;
1788                         zero_range = allocated;
1789                         if (zero_range > max_blocks)
1790                                 zero_range = max_blocks;
1791
1792                         newblock = iblock - ee_block + ee_start;
1793                         err = ext4_ext_zero_unwritten_range(inode_ref, newblock,
1794                                         zero_range);
1795                         if (err != EOK)
1796                                 goto out2;
1797
1798                         err = ext4_ext_convert_to_initialized(inode_ref, &path,
1799                                         iblock, zero_range);
1800                         if (err != EOK)
1801                                 goto out2;
1802
1803                         goto out;
1804                 }
1805         }
1806
1807         /*
1808          * requested block isn't allocated yet
1809          * we couldn't try to create block if create flag is zero
1810          */
1811         if (!create) {
1812                 goto out2;
1813         }
1814
1815         /* find next allocated block so that we know how many
1816          * blocks we can allocate without ovelapping next extent */
1817         next = ext4_ext_next_allocated_block(path);
1818         allocated = next - iblock;
1819         if (allocated > max_blocks)
1820                 allocated = max_blocks;
1821
1822         /* allocate new block */
1823         goal = ext4_ext_find_goal(inode_ref, path, iblock);
1824         newblock = ext4_new_meta_blocks(inode_ref, goal, 0, &allocated, &err);
1825         if (!newblock)
1826                 goto out2;
1827
1828         /* try to insert new extent into found leaf and return */
1829         newex.first_block = to_le32(iblock);
1830         ext4_ext_store_pblock(&newex, newblock);
1831         newex.block_count = to_le16(allocated);
1832         err = ext4_ext_insert_extent(inode_ref, &path, &newex, 0);
1833         if (err != EOK) {
1834                 /* free data blocks we just allocated */
1835                 ext4_ext_free_blocks(inode_ref, ext4_ext_pblock(&newex),
1836                                      to_le16(newex.block_count), 0);
1837                 goto out2;
1838         }
1839
1840         /* previous routine could use block we allocated */
1841         newblock = ext4_ext_pblock(&newex);
1842
1843 out:
1844         if (allocated > max_blocks)
1845                 allocated = max_blocks;
1846
1847         if (result)
1848                 *result = newblock;
1849
1850         if (blocks_count)
1851                 *blocks_count = allocated;
1852
1853 out2:
1854         if (path) {
1855                 ext4_ext_drop_refs(inode_ref, path, 0);
1856                 free(path);
1857         }
1858
1859         return err;
1860 }
1861 #endif