lib/ext2fs/extent.c

   1 /*
   2  * extent.c --- routines to implement extents support
   3  *
   4  * Copyright (C) 2007 Theodore Ts'o.
   5  *
   6  * %Begin-Header%
   7  * This file may be redistributed under the terms of the GNU Library
   8  * General Public License, version 2.
   9  * %End-Header%
  10  */
  11
  12 #include "config.h"
  13 #include <stdio.h>
  14 #include <string.h>
  15 #if HAVE_UNISTD_H
  16 #include <unistd.h>
  17 #endif
  18 #if HAVE_ERRNO_H
  19 #include <errno.h>
  20 #endif
  21 #if HAVE_SYS_STAT_H
  22 #include <sys/stat.h>
  23 #endif
  24 #if HAVE_SYS_TYPES_H
  25 #include <sys/types.h>
  26 #endif
  27
  28 #include "ext2_fs.h"
  29 #include "ext2fsP.h"
  30 #include "e2image.h"
  31
  32 /*
  33  * Definitions to be dropped in lib/ext2fs/ext2fs.h
  34  */
  35
  36 /*
  37  * Private definitions
  38  */
  39
  40 struct extent_path {
  41         char            *buf;
  42         int             entries;
  43         int             max_entries;
  44         int             left;
  45         int             visit_num;
  46         int             flags;
  47         blk64_t         end_blk;
  48         void            *curr;
  49 };
  50
  51
  52 struct ext2_extent_handle {
  53         errcode_t               magic;
  54         ext2_filsys             fs;
  55         ext2_ino_t              ino;
  56         struct ext2_inode       *inode;
  57         struct ext2_inode       inodebuf;
  58         int                     type;
  59         int                     level;
  60         int                     max_depth;
  61         int                     max_paths;
  62         struct extent_path      *path;
  63 };
  64
  65 struct ext2_extent_path {
  66         errcode_t               magic;
  67         int                     leaf_height;
  68         blk64_t                 lblk;
  69 };
  70
  71 /*
  72  *  Useful Debugging stuff
  73  */
  74
  75 #ifdef DEBUG
  76 static void dbg_show_header(struct ext3_extent_header *eh)
  77 {
  78         printf("header: magic=%x entries=%u max=%u depth=%u generation=%u\n",
  79                         ext2fs_le16_to_cpu(eh->eh_magic),
  80                         ext2fs_le16_to_cpu(eh->eh_entries),
  81                         ext2fs_le16_to_cpu(eh->eh_max),
  82                         ext2fs_le16_to_cpu(eh->eh_depth),
  83                         ext2fs_le32_to_cpu(eh->eh_generation));
  84 }
  85
  86 static void dbg_show_index(struct ext3_extent_idx *ix)
  87 {
  88         printf("index: block=%u leaf=%u leaf_hi=%u unused=%u\n",
  89                         ext2fs_le32_to_cpu(ix->ei_block),
  90                         ext2fs_le32_to_cpu(ix->ei_leaf),
  91                         ext2fs_le16_to_cpu(ix->ei_leaf_hi),
  92                         ext2fs_le16_to_cpu(ix->ei_unused));
  93 }
  94
  95 static void dbg_show_extent(struct ext3_extent *ex)
  96 {
  97         printf("extent: block=%u-%u len=%u start=%u start_hi=%u\n",
  98                         ext2fs_le32_to_cpu(ex->ee_block),
  99                         ext2fs_le32_to_cpu(ex->ee_block) +
 100                         ext2fs_le16_to_cpu(ex->ee_len) - 1,
 101                         ext2fs_le16_to_cpu(ex->ee_len),
 102                         ext2fs_le32_to_cpu(ex->ee_start),
 103                         ext2fs_le16_to_cpu(ex->ee_start_hi));
 104 }
 105
 106 static void dbg_print_extent(char *desc, struct ext2fs_extent *extent)
 107 {
 108         if (desc)
 109                 printf("%s: ", desc);
 110         printf("extent: lblk %llu--%llu, len %u, pblk %llu, flags: ",
 111                extent->e_lblk, extent->e_lblk + extent->e_len - 1,
 112                extent->e_len, extent->e_pblk);
 113         if (extent->e_flags & EXT2_EXTENT_FLAGS_LEAF)
 114                 fputs("LEAF ", stdout);
 115         if (extent->e_flags & EXT2_EXTENT_FLAGS_UNINIT)
 116                 fputs("UNINIT ", stdout);
 117         if (extent->e_flags & EXT2_EXTENT_FLAGS_SECOND_VISIT)
 118                 fputs("2ND_VISIT ", stdout);
 119         if (!extent->e_flags)
 120                 fputs("(none)", stdout);
 121         fputc('\n', stdout);
 122
 123 }
 124
 125 #else
 126 #define dbg_show_header(eh) do { } while (0)
 127 #define dbg_show_index(ix) do { } while (0)
 128 #define dbg_show_extent(ex) do { } while (0)
 129 #define dbg_print_extent(desc, ex) do { } while (0)
 130 #endif
 131
 132 /*
 133  * Verify the extent header as being sane
 134  */
 135 errcode_t ext2fs_extent_header_verify(void *ptr, int size)
 136 {
 137         int eh_max, entry_size;
 138         struct ext3_extent_header *eh = ptr;
 139
 140         dbg_show_header(eh);
 141         if (ext2fs_le16_to_cpu(eh->eh_magic) != EXT3_EXT_MAGIC)
 142                 return EXT2_ET_EXTENT_HEADER_BAD;
 143         if (ext2fs_le16_to_cpu(eh->eh_entries) > ext2fs_le16_to_cpu(eh->eh_max))
 144                 return EXT2_ET_EXTENT_HEADER_BAD;
 145         if (eh->eh_depth == 0)
 146                 entry_size = sizeof(struct ext3_extent);
 147         else
 148                 entry_size = sizeof(struct ext3_extent_idx);
 149
 150         eh_max = (size - sizeof(*eh)) / entry_size;
 151         /* Allow two extent-sized items at the end of the block, for
 152          * ext4_extent_tail with checksum in the future. */
 153         if ((ext2fs_le16_to_cpu(eh->eh_max) > eh_max) ||
 154             (ext2fs_le16_to_cpu(eh->eh_max) < (eh_max - 2)))
 155                 return EXT2_ET_EXTENT_HEADER_BAD;
 156
 157         return 0;
 158 }
 159
 160
 161 /*
 162  * Begin functions to handle an inode's extent information
 163  */
 164 void ext2fs_extent_free(ext2_extent_handle_t handle)
 165 {
 166         int                     i;
 167
 168         if (!handle)
 169                 return;
 170
 171         if (handle->path) {
 172                 for (i = 1; i < handle->max_paths; i++) {
 173                         if (handle->path[i].buf)
 174                                 ext2fs_free_mem(&handle->path[i].buf);
 175                 }
 176                 ext2fs_free_mem(&handle->path);
 177         }
 178         ext2fs_free_mem(&handle);
 179 }
 180
 181 errcode_t ext2fs_extent_open(ext2_filsys fs, ext2_ino_t ino,
 182                                     ext2_extent_handle_t *ret_handle)
 183 {
 184         return ext2fs_extent_open2(fs, ino, NULL, ret_handle);
 185 }
 186
 187 errcode_t ext2fs_extent_open2(ext2_filsys fs, ext2_ino_t ino,
 188                                     struct ext2_inode *inode,
 189                                     ext2_extent_handle_t *ret_handle)
 190 {
 191         struct ext2_extent_handle       *handle;
 192         errcode_t                       retval;
 193         int                             i;
 194         struct ext3_extent_header       *eh;
 195
 196         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 197
 198         if (!inode)
 199                 if ((ino == 0) || (ino > fs->super->s_inodes_count))
 200                         return EXT2_ET_BAD_INODE_NUM;
 201
 202         retval = ext2fs_get_mem(sizeof(struct ext2_extent_handle), &handle);
 203         if (retval)
 204                 return retval;
 205         memset(handle, 0, sizeof(struct ext2_extent_handle));
 206
 207         handle->ino = ino;
 208         handle->fs = fs;
 209
 210         if (inode) {
 211                 handle->inode = inode;
 212         } else {
 213                 handle->inode = &handle->inodebuf;
 214                 retval = ext2fs_read_inode(fs, ino, handle->inode);
 215                 if (retval)
 216                         goto errout;
 217         }
 218
 219         eh = (struct ext3_extent_header *) &handle->inode->i_block[0];
 220
 221         for (i=0; i < EXT2_N_BLOCKS; i++)
 222                 if (handle->inode->i_block[i])
 223                         break;
 224         if (i >= EXT2_N_BLOCKS) {
 225                 eh->eh_magic = ext2fs_cpu_to_le16(EXT3_EXT_MAGIC);
 226                 eh->eh_depth = 0;
 227                 eh->eh_entries = 0;
 228                 i = (sizeof(handle->inode->i_block) - sizeof(*eh)) /
 229                         sizeof(struct ext3_extent);
 230                 eh->eh_max = ext2fs_cpu_to_le16(i);
 231                 handle->inode->i_flags |= EXT4_EXTENTS_FL;
 232         }
 233
 234         if (!(handle->inode->i_flags & EXT4_EXTENTS_FL)) {
 235                 retval = EXT2_ET_INODE_NOT_EXTENT;
 236                 goto errout;
 237         }
 238
 239         retval = ext2fs_extent_header_verify(eh, sizeof(handle->inode->i_block));
 240         if (retval)
 241                 goto errout;
 242
 243         handle->max_depth = ext2fs_le16_to_cpu(eh->eh_depth);
 244         handle->type = ext2fs_le16_to_cpu(eh->eh_magic);
 245
 246         handle->max_paths = handle->max_depth + 1;
 247         retval = ext2fs_get_memzero(handle->max_paths *
 248                                     sizeof(struct extent_path),
 249                                     &handle->path);
 250         handle->path[0].buf = (char *) handle->inode->i_block;
 251
 252         handle->path[0].left = handle->path[0].entries =
 253                 ext2fs_le16_to_cpu(eh->eh_entries);
 254         handle->path[0].max_entries = ext2fs_le16_to_cpu(eh->eh_max);
 255         handle->path[0].curr = 0;
 256         handle->path[0].end_blk =
 257                 (EXT2_I_SIZE(handle->inode) + fs->blocksize - 1) >>
 258                  EXT2_BLOCK_SIZE_BITS(fs->super);
 259         handle->path[0].visit_num = 1;
 260         handle->level = 0;
 261         handle->magic = EXT2_ET_MAGIC_EXTENT_HANDLE;
 262
 263         *ret_handle = handle;
 264         return 0;
 265
 266 errout:
 267         ext2fs_extent_free(handle);
 268         return retval;
 269 }
 270
 271 /*
 272  * This function is responsible for (optionally) moving through the
 273  * extent tree and then returning the current extent
 274  */
 275 errcode_t ext2fs_extent_get(ext2_extent_handle_t handle,
 276                             int flags, struct ext2fs_extent *extent)
 277 {
 278         struct extent_path      *path, *newpath;
 279         struct ext3_extent_header       *eh;
 280         struct ext3_extent_idx          *ix = 0;
 281         struct ext3_extent              *ex;
 282         errcode_t                       retval;
 283         blk64_t                         blk;
 284         blk64_t                         end_blk;
 285         int                             orig_op, op;
 286
 287         EXT2_CHECK_MAGIC(handle, EXT2_ET_MAGIC_EXTENT_HANDLE);
 288
 289         if (!handle->path)
 290                 return EXT2_ET_NO_CURRENT_NODE;
 291
 292         orig_op = op = flags & EXT2_EXTENT_MOVE_MASK;
 293
 294 retry:
 295         path = handle->path + handle->level;
 296         if ((orig_op == EXT2_EXTENT_NEXT) ||
 297             (orig_op == EXT2_EXTENT_NEXT_LEAF)) {
 298                 if (handle->level < handle->max_depth) {
 299                         /* interior node */
 300                         if (path->visit_num == 0) {
 301                                 path->visit_num++;
 302                                 op = EXT2_EXTENT_DOWN;
 303                         } else if (path->left > 0)
 304                                 op = EXT2_EXTENT_NEXT_SIB;
 305                         else if (handle->level > 0)
 306                                 op = EXT2_EXTENT_UP;
 307                         else
 308                                 return EXT2_ET_EXTENT_NO_NEXT;
 309                 } else {
 310                         /* leaf node */
 311                         if (path->left > 0)
 312                                 op = EXT2_EXTENT_NEXT_SIB;
 313                         else if (handle->level > 0)
 314                                 op = EXT2_EXTENT_UP;
 315                         else
 316                                 return EXT2_ET_EXTENT_NO_NEXT;
 317                 }
 318                 if (op != EXT2_EXTENT_NEXT_SIB) {
 319 #ifdef DEBUG_GET_EXTENT
 320                         printf("<<<< OP = %s\n",
 321                                (op == EXT2_EXTENT_DOWN) ? "down" :
 322                                ((op == EXT2_EXTENT_UP) ? "up" : "unknown"));
 323 #endif
 324                 }
 325         }
 326
 327         if ((orig_op == EXT2_EXTENT_PREV) ||
 328             (orig_op == EXT2_EXTENT_PREV_LEAF)) {
 329                 if (handle->level < handle->max_depth) {
 330                         /* interior node */
 331                         if (path->visit_num > 0 ) {
 332                                 /* path->visit_num = 0; */
 333                                 op = EXT2_EXTENT_DOWN_AND_LAST;
 334                         } else if (path->left < path->entries-1)
 335                                 op = EXT2_EXTENT_PREV_SIB;
 336                         else if (handle->level > 0)
 337                                 op = EXT2_EXTENT_UP;
 338                         else
 339                                 return EXT2_ET_EXTENT_NO_PREV;
 340                 } else {
 341                         /* leaf node */
 342                         if (path->left < path->entries-1)
 343                                 op = EXT2_EXTENT_PREV_SIB;
 344                         else if (handle->level > 0)
 345                                 op = EXT2_EXTENT_UP;
 346                         else
 347                                 return EXT2_ET_EXTENT_NO_PREV;
 348                 }
 349                 if (op != EXT2_EXTENT_PREV_SIB) {
 350 #ifdef DEBUG_GET_EXTENT
 351                         printf("<<<< OP = %s\n",
 352                                (op == EXT2_EXTENT_DOWN_AND_LAST) ? "down/last" :
 353                                ((op == EXT2_EXTENT_UP) ? "up" : "unknown"));
 354 #endif
 355                 }
 356         }
 357
 358         if (orig_op == EXT2_EXTENT_LAST_LEAF) {
 359                 if ((handle->level < handle->max_depth) &&
 360                     (path->left == 0))
 361                         op = EXT2_EXTENT_DOWN;
 362                 else
 363                         op = EXT2_EXTENT_LAST_SIB;
 364 #ifdef DEBUG_GET_EXTENT
 365                 printf("<<<< OP = %s\n",
 366                            (op == EXT2_EXTENT_DOWN) ? "down" : "last_sib");
 367 #endif
 368         }
 369
 370         switch (op) {
 371         case EXT2_EXTENT_CURRENT:
 372                 ix = path->curr;
 373                 break;
 374         case EXT2_EXTENT_ROOT:
 375                 handle->level = 0;
 376                 path = handle->path + handle->level;
 377                 /* fallthrough */
 378         case EXT2_EXTENT_FIRST_SIB:
 379                 path->left = path->entries;
 380                 path->curr = 0;
 381                 /* fallthrough */
 382         case EXT2_EXTENT_NEXT_SIB:
 383                 if (path->left <= 0)
 384                         return EXT2_ET_EXTENT_NO_NEXT;
 385                 if (path->curr) {
 386                         ix = path->curr;
 387                         ix++;
 388                 } else {
 389                         eh = (struct ext3_extent_header *) path->buf;
 390                         ix = EXT_FIRST_INDEX(eh);
 391                 }
 392                 path->left--;
 393                 path->curr = ix;
 394                 path->visit_num = 0;
 395                 break;
 396         case EXT2_EXTENT_PREV_SIB:
 397                 if (!path->curr ||
 398                     path->left+1 >= path->entries)
 399                         return EXT2_ET_EXTENT_NO_PREV;
 400                 ix = path->curr;
 401                 ix--;
 402                 path->curr = ix;
 403                 path->left++;
 404                 if (handle->level < handle->max_depth)
 405                         path->visit_num = 1;
 406                 break;
 407         case EXT2_EXTENT_LAST_SIB:
 408                 eh = (struct ext3_extent_header *) path->buf;
 409                 path->curr = EXT_LAST_EXTENT(eh);
 410                 ix = path->curr;
 411                 path->left = 0;
 412                 path->visit_num = 0;
 413                 break;
 414         case EXT2_EXTENT_UP:
 415                 if (handle->level <= 0)
 416                         return EXT2_ET_EXTENT_NO_UP;
 417                 handle->level--;
 418                 path--;
 419                 ix = path->curr;
 420                 if ((orig_op == EXT2_EXTENT_PREV) ||
 421                     (orig_op == EXT2_EXTENT_PREV_LEAF))
 422                         path->visit_num = 0;
 423                 break;
 424         case EXT2_EXTENT_DOWN:
 425         case EXT2_EXTENT_DOWN_AND_LAST:
 426                 if (!path->curr ||(handle->level >= handle->max_depth))
 427                         return EXT2_ET_EXTENT_NO_DOWN;
 428
 429                 ix = path->curr;
 430                 newpath = path + 1;
 431                 if (!newpath->buf) {
 432                         retval = ext2fs_get_mem(handle->fs->blocksize,
 433                                                 &newpath->buf);
 434                         if (retval)
 435                                 return retval;
 436                 }
 437                 blk = ext2fs_le32_to_cpu(ix->ei_leaf) +
 438                         ((__u64) ext2fs_le16_to_cpu(ix->ei_leaf_hi) << 32);
 439                 if ((handle->fs->flags & EXT2_FLAG_IMAGE_FILE) &&
 440                     (handle->fs->io != handle->fs->image_io))
 441                         memset(newpath->buf, 0, handle->fs->blocksize);
 442                 else {
 443                         retval = io_channel_read_blk64(handle->fs->io,
 444                                                      blk, 1, newpath->buf);
 445                         if (retval)
 446                                 return retval;
 447                 }
 448                 handle->level++;
 449
 450                 eh = (struct ext3_extent_header *) newpath->buf;
 451
 452                 retval = ext2fs_extent_header_verify(eh, handle->fs->blocksize);
 453                 if (retval) {
 454                         handle->level--;
 455                         return retval;
 456                 }
 457
 458                 if (!(handle->fs->flags & EXT2_FLAG_IGNORE_CSUM_ERRORS) &&
 459                     !ext2fs_extent_block_csum_verify(handle->fs, handle->ino,
 460                                                      eh)) {
 461                         handle->level--;
 462                         return EXT2_ET_EXTENT_CSUM_INVALID;
 463                 }
 464
 465                 newpath->left = newpath->entries =
 466                         ext2fs_le16_to_cpu(eh->eh_entries);
 467                 newpath->max_entries = ext2fs_le16_to_cpu(eh->eh_max);
 468
 469                 if (path->left > 0) {
 470                         ix++;
 471                         newpath->end_blk = ext2fs_le32_to_cpu(ix->ei_block);
 472                 } else
 473                         newpath->end_blk = path->end_blk;
 474
 475                 path = newpath;
 476                 if (op == EXT2_EXTENT_DOWN) {
 477                         ix = EXT_FIRST_INDEX((struct ext3_extent_header *) eh);
 478                         path->curr = ix;
 479                         path->left = path->entries - 1;
 480                         path->visit_num = 0;
 481                 } else {
 482                         ix = EXT_LAST_INDEX((struct ext3_extent_header *) eh);
 483                         path->curr = ix;
 484                         path->left = 0;
 485                         if (handle->level < handle->max_depth)
 486                                 path->visit_num = 1;
 487                 }
 488 #ifdef DEBUG_GET_EXTENT
 489                 printf("Down to level %d/%d, end_blk=%llu\n",
 490                            handle->level, handle->max_depth,
 491                            path->end_blk);
 492 #endif
 493                 break;
 494         default:
 495                 return EXT2_ET_OP_NOT_SUPPORTED;
 496         }
 497
 498         if (!ix)
 499                 return EXT2_ET_NO_CURRENT_NODE;
 500
 501         extent->e_flags = 0;
 502 #ifdef DEBUG_GET_EXTENT
 503         printf("(Left %d)\n", path->left);
 504 #endif
 505
 506         if (handle->level == handle->max_depth) {
 507                 ex = (struct ext3_extent *) ix;
 508
 509                 extent->e_pblk = ext2fs_le32_to_cpu(ex->ee_start) +
 510                         ((__u64) ext2fs_le16_to_cpu(ex->ee_start_hi) << 32);
 511                 extent->e_lblk = ext2fs_le32_to_cpu(ex->ee_block);
 512                 extent->e_len = ext2fs_le16_to_cpu(ex->ee_len);
 513                 extent->e_flags |= EXT2_EXTENT_FLAGS_LEAF;
 514                 if (extent->e_len > EXT_INIT_MAX_LEN) {
 515                         extent->e_len -= EXT_INIT_MAX_LEN;
 516                         extent->e_flags |= EXT2_EXTENT_FLAGS_UNINIT;
 517                 }
 518         } else {
 519                 extent->e_pblk = ext2fs_le32_to_cpu(ix->ei_leaf) +
 520                         ((__u64) ext2fs_le16_to_cpu(ix->ei_leaf_hi) << 32);
 521                 extent->e_lblk = ext2fs_le32_to_cpu(ix->ei_block);
 522                 if (path->left > 0) {
 523                         ix++;
 524                         end_blk = ext2fs_le32_to_cpu(ix->ei_block);
 525                 } else
 526                         end_blk = path->end_blk;
 527
 528                 extent->e_len = end_blk - extent->e_lblk;
 529         }
 530         if (path->visit_num)
 531                 extent->e_flags |= EXT2_EXTENT_FLAGS_SECOND_VISIT;
 532
 533         if (((orig_op == EXT2_EXTENT_NEXT_LEAF) ||
 534              (orig_op == EXT2_EXTENT_PREV_LEAF)) &&
 535             (handle->level != handle->max_depth))
 536                 goto retry;
 537
 538         if ((orig_op == EXT2_EXTENT_LAST_LEAF) &&
 539             ((handle->level != handle->max_depth) ||
 540              (path->left != 0)))
 541                 goto retry;
 542
 543         return 0;
 544 }
 545
 546 static errcode_t update_path(ext2_extent_handle_t handle)
 547 {
 548         blk64_t                         blk;
 549         errcode_t                       retval;
 550         struct ext3_extent_idx          *ix;
 551         struct ext3_extent_header       *eh;
 552
 553         if (handle->level == 0) {
 554                 retval = ext2fs_write_inode(handle->fs, handle->ino,
 555                                             handle->inode);
 556         } else {
 557                 ix = handle->path[handle->level - 1].curr;
 558                 blk = ext2fs_le32_to_cpu(ix->ei_leaf) +
 559                         ((__u64) ext2fs_le16_to_cpu(ix->ei_leaf_hi) << 32);
 560
 561                 /* then update the checksum */
 562                 eh = (struct ext3_extent_header *)
 563                                 handle->path[handle->level].buf;
 564                 retval = ext2fs_extent_block_csum_set(handle->fs, handle->ino,
 565                                                       eh);
 566                 if (retval)
 567                         return retval;
 568
 569                 retval = io_channel_write_blk64(handle->fs->io,
 570                                       blk, 1, handle->path[handle->level].buf);
 571         }
 572         return retval;
 573 }
 574
 575 #if 0
 576 errcode_t ext2fs_extent_save_path(ext2_extent_handle_t handle,
 577                                   ext2_extent_path_t *ret_path)
 578 {
 579         ext2_extent_path_t      save_path;
 580         struct ext2fs_extent    extent;
 581         struct ext2_extent_info info;
 582         errcode_t               retval;
 583
 584         retval = ext2fs_extent_get(handle, EXT2_EXTENT_CURRENT, &extent);
 585         if (retval)
 586                 return retval;
 587
 588         retval = ext2fs_extent_get_info(handle, &info);
 589         if (retval)
 590                 return retval;
 591
 592         retval = ext2fs_get_mem(sizeof(struct ext2_extent_path), &save_path);
 593         if (retval)
 594                 return retval;
 595         memset(save_path, 0, sizeof(struct ext2_extent_path));
 596
 597         save_path->magic = EXT2_ET_MAGIC_EXTENT_PATH;
 598         save_path->leaf_height = info.max_depth - info.curr_level - 1;
 599         save_path->lblk = extent.e_lblk;
 600
 601         *ret_path = save_path;
 602         return 0;
 603 }
 604
 605 errcode_t ext2fs_extent_free_path(ext2_extent_path_t path)
 606 {
 607         EXT2_CHECK_MAGIC(path, EXT2_ET_MAGIC_EXTENT_PATH);
 608
 609         ext2fs_free_mem(&path);
 610         return 0;
 611 }
 612 #endif
 613
 614 /*
 615  * Go to the node at leaf_level which contains logical block blk.
 616  *
 617  * leaf_level is height from the leaf node level, i.e.
 618  * leaf_level 0 is at leaf node, leaf_level 1 is 1 above etc.
 619  *
 620  * If "blk" has no mapping (hole) then handle is left at last
 621  * extent before blk.
 622  */
 623 errcode_t ext2fs_extent_goto2(ext2_extent_handle_t handle,
 624                               int leaf_level, blk64_t blk)
 625 {
 626         struct ext2fs_extent    extent;
 627         errcode_t               retval;
 628
 629         retval = ext2fs_extent_get(handle, EXT2_EXTENT_ROOT, &extent);
 630         if (retval) {
 631                 if (retval == EXT2_ET_EXTENT_NO_NEXT)
 632                         retval = EXT2_ET_EXTENT_NOT_FOUND;
 633                 return retval;
 634         }
 635
 636         if (leaf_level > handle->max_depth) {
 637 #ifdef DEBUG
 638                 printf("leaf level %d greater than tree depth %d\n",
 639                         leaf_level, handle->max_depth);
 640 #endif
 641                 return EXT2_ET_OP_NOT_SUPPORTED;
 642         }
 643
 644 #ifdef DEBUG
 645         printf("goto extent ino %u, level %d, %llu\n", handle->ino,
 646                leaf_level, blk);
 647 #endif
 648
 649 #ifdef DEBUG_GOTO_EXTENTS
 650         dbg_print_extent("root", &extent);
 651 #endif
 652         while (1) {
 653                 if (handle->max_depth - handle->level == leaf_level) {
 654                         /* block is in this &extent */
 655                         if ((blk >= extent.e_lblk) &&
 656                             (blk < extent.e_lblk + extent.e_len))
 657                                 return 0;
 658                         if (blk < extent.e_lblk) {
 659                                 retval = ext2fs_extent_get(handle,
 660                                                            EXT2_EXTENT_PREV_SIB,
 661                                                            &extent);
 662                                 return EXT2_ET_EXTENT_NOT_FOUND;
 663                         }
 664                         retval = ext2fs_extent_get(handle,
 665                                                    EXT2_EXTENT_NEXT_SIB,
 666                                                    &extent);
 667                         if (retval == EXT2_ET_EXTENT_NO_NEXT)
 668                                 return EXT2_ET_EXTENT_NOT_FOUND;
 669                         if (retval)
 670                                 return retval;
 671                         continue;
 672                 }
 673
 674                 retval = ext2fs_extent_get(handle, EXT2_EXTENT_NEXT_SIB,
 675                                            &extent);
 676                 if (retval == EXT2_ET_EXTENT_NO_NEXT)
 677                         goto go_down;
 678                 if (retval)
 679                         return retval;
 680
 681 #ifdef DEBUG_GOTO_EXTENTS
 682                 dbg_print_extent("next", &extent);
 683 #endif
 684                 if (blk == extent.e_lblk)
 685                         goto go_down;
 686                 if (blk > extent.e_lblk)
 687                         continue;
 688
 689                 retval = ext2fs_extent_get(handle, EXT2_EXTENT_PREV_SIB,
 690                                            &extent);
 691                 if (retval)
 692                         return retval;
 693
 694 #ifdef DEBUG_GOTO_EXTENTS
 695                 dbg_print_extent("prev", &extent);
 696 #endif
 697
 698         go_down:
 699                 retval = ext2fs_extent_get(handle, EXT2_EXTENT_DOWN,
 700                                            &extent);
 701                 if (retval)
 702                         return retval;
 703
 704 #ifdef DEBUG_GOTO_EXTENTS
 705                 dbg_print_extent("down", &extent);
 706 #endif
 707         }
 708 }
 709
 710 errcode_t ext2fs_extent_goto(ext2_extent_handle_t handle,
 711                              blk64_t blk)
 712 {
 713         return ext2fs_extent_goto2(handle, 0, blk);
 714 }
 715
 716 /*
 717  * Traverse back up to root fixing parents of current node as needed.
 718  *
 719  * If we changed start of first entry in a node, fix parent index start
 720  * and so on.
 721  *
 722  * Safe to call for any position in node; if not at the first entry,
 723  * will  simply return.
 724  */
 725 errcode_t ext2fs_extent_fix_parents(ext2_extent_handle_t handle)
 726 {
 727         int                             retval = 0;
 728         int                             orig_height;
 729         blk64_t                         start;
 730         struct extent_path              *path;
 731         struct ext2fs_extent            extent;
 732         struct ext2_extent_info         info;
 733
 734         EXT2_CHECK_MAGIC(handle, EXT2_ET_MAGIC_EXTENT_HANDLE);
 735
 736         if (!(handle->fs->flags & EXT2_FLAG_RW))
 737                 return EXT2_ET_RO_FILSYS;
 738
 739         if (!handle->path)
 740                 return EXT2_ET_NO_CURRENT_NODE;
 741
 742         path = handle->path + handle->level;
 743         if (!path->curr)
 744                 return EXT2_ET_NO_CURRENT_NODE;
 745
 746         retval = ext2fs_extent_get(handle, EXT2_EXTENT_CURRENT, &extent);
 747         if (retval)
 748                 goto done;
 749
 750         /* modified node's start block */
 751         start = extent.e_lblk;
 752
 753         if ((retval = ext2fs_extent_get_info(handle, &info)))
 754                 return retval;
 755         orig_height = info.max_depth - info.curr_level;
 756
 757         /* traverse up until index not first, or startblk matches, or top */
 758         while (handle->level > 0 &&
 759                (path->left == path->entries - 1)) {
 760                 retval = ext2fs_extent_get(handle, EXT2_EXTENT_UP, &extent);
 761                 if (retval)
 762                         goto done;
 763                 if (extent.e_lblk == start)
 764                         break;
 765                 path = handle->path + handle->level;
 766                 extent.e_len += (extent.e_lblk - start);
 767                 extent.e_lblk = start;
 768                 retval = ext2fs_extent_replace(handle, 0, &extent);
 769                 if (retval)
 770                         goto done;
 771                 update_path(handle);
 772         }
 773
 774         /* put handle back to where we started */
 775         retval = ext2fs_extent_goto2(handle, orig_height, start);
 776 done:
 777         return retval;
 778 }
 779
 780 errcode_t ext2fs_extent_replace(ext2_extent_handle_t handle,
 781                                 int flags EXT2FS_ATTR((unused)),
 782                                 struct ext2fs_extent *extent)
 783 {
 784         struct extent_path              *path;
 785         struct ext3_extent_idx          *ix;
 786         struct ext3_extent              *ex;
 787
 788         EXT2_CHECK_MAGIC(handle, EXT2_ET_MAGIC_EXTENT_HANDLE);
 789
 790         if (!(handle->fs->flags & EXT2_FLAG_RW))
 791                 return EXT2_ET_RO_FILSYS;
 792
 793         if (!handle->path)
 794                 return EXT2_ET_NO_CURRENT_NODE;
 795
 796         path = handle->path + handle->level;
 797         if (!path->curr)
 798                 return EXT2_ET_NO_CURRENT_NODE;
 799
 800 #ifdef DEBUG
 801         printf("extent replace: %u ", handle->ino);
 802         dbg_print_extent(0, extent);
 803 #endif
 804
 805         if (handle->level == handle->max_depth) {
 806                 ex = path->curr;
 807
 808                 ex->ee_block = ext2fs_cpu_to_le32(extent->e_lblk);
 809                 ex->ee_start = ext2fs_cpu_to_le32(extent->e_pblk & 0xFFFFFFFF);
 810                 ex->ee_start_hi = ext2fs_cpu_to_le16(extent->e_pblk >> 32);
 811                 if (extent->e_flags & EXT2_EXTENT_FLAGS_UNINIT) {
 812                         if (extent->e_len > EXT_UNINIT_MAX_LEN)
 813                                 return EXT2_ET_EXTENT_INVALID_LENGTH;
 814                         ex->ee_len = ext2fs_cpu_to_le16(extent->e_len +
 815                                                         EXT_INIT_MAX_LEN);
 816                 } else {
 817                         if (extent->e_len > EXT_INIT_MAX_LEN)
 818                                 return EXT2_ET_EXTENT_INVALID_LENGTH;
 819                         ex->ee_len = ext2fs_cpu_to_le16(extent->e_len);
 820                 }
 821         } else {
 822                 ix = path->curr;
 823
 824                 ix->ei_leaf = ext2fs_cpu_to_le32(extent->e_pblk & 0xFFFFFFFF);
 825                 ix->ei_leaf_hi = ext2fs_cpu_to_le16(extent->e_pblk >> 32);
 826                 ix->ei_block = ext2fs_cpu_to_le32(extent->e_lblk);
 827                 ix->ei_unused = 0;
 828         }
 829         update_path(handle);
 830         return 0;
 831 }
 832
 833 /*
 834  * allocate a new block, move half the current node to it, and update parent
 835  *
 836  * handle will be left pointing at original record.
 837  */
 838 errcode_t ext2fs_extent_node_split(ext2_extent_handle_t handle)
 839 {
 840         errcode_t                       retval = 0;
 841         blk64_t                         new_node_pblk;
 842         blk64_t                         new_node_start;
 843         blk64_t                         orig_lblk;
 844         blk64_t                         goal_blk = 0;
 845         int                             orig_height;
 846         char                            *block_buf = NULL;
 847         struct ext2fs_extent            extent;
 848         struct extent_path              *path, *newpath = 0;
 849         struct ext3_extent_header       *eh, *neweh;
 850         int                             tocopy;
 851         int                             new_root = 0;
 852         struct ext2_extent_info         info;
 853
 854         /* basic sanity */
 855         EXT2_CHECK_MAGIC(handle, EXT2_ET_MAGIC_EXTENT_HANDLE);
 856
 857         if (!(handle->fs->flags & EXT2_FLAG_RW))
 858                 return EXT2_ET_RO_FILSYS;
 859
 860         if (!handle->path)
 861                 return EXT2_ET_NO_CURRENT_NODE;
 862
 863 #ifdef DEBUG
 864         printf("splitting node at level %d\n", handle->level);
 865 #endif
 866         retval = ext2fs_extent_get(handle, EXT2_EXTENT_CURRENT, &extent);
 867         if (retval)
 868                 goto done;
 869
 870         retval = ext2fs_extent_get_info(handle, &info);
 871         if (retval)
 872                 goto done;
 873
 874         /* save the position we were originally splitting... */
 875         orig_height = info.max_depth - info.curr_level;
 876         orig_lblk = extent.e_lblk;
 877
 878         /* Is there room in the parent for a new entry? */
 879         if (handle->level &&
 880                         (handle->path[handle->level - 1].entries >=
 881                          handle->path[handle->level - 1].max_entries)) {
 882
 883 #ifdef DEBUG
 884                 printf("parent level %d full; splitting it too\n",
 885                                                         handle->level - 1);
 886 #endif
 887                 /* split the parent */
 888                 retval = ext2fs_extent_get(handle, EXT2_EXTENT_UP, &extent);
 889                 if (retval)
 890                         goto done;
 891                 goal_blk = extent.e_pblk;
 892
 893                 retval = ext2fs_extent_node_split(handle);
 894                 if (retval)
 895                         goto done;
 896
 897                 /* get handle back to our original split position */
 898                 retval = ext2fs_extent_goto2(handle, orig_height, orig_lblk);
 899                 if (retval)
 900                         goto done;
 901         }
 902
 903         /* At this point, parent should have room for this split */
 904         path = handle->path + handle->level;
 905         if (!path->curr)
 906                 return EXT2_ET_NO_CURRENT_NODE;
 907
 908         /* extent header of the current node we'll split */
 909         eh = (struct ext3_extent_header *)path->buf;
 910
 911         /* splitting root level means moving them all out */
 912         if (handle->level == 0) {
 913                 new_root = 1;
 914                 tocopy = ext2fs_le16_to_cpu(eh->eh_entries);
 915                 retval = ext2fs_get_memzero((handle->max_paths + 1) *
 916                                             sizeof(struct extent_path),
 917                                             &newpath);
 918                 if (retval)
 919                         goto done;
 920         } else {
 921                 tocopy = ext2fs_le16_to_cpu(eh->eh_entries) / 2;
 922         }
 923
 924 #ifdef DEBUG
 925         printf("will copy out %d of %d entries at level %d\n",
 926                                 tocopy, ext2fs_le16_to_cpu(eh->eh_entries),
 927                                 handle->level);
 928 #endif
 929
 930         if (!tocopy) {
 931 #ifdef DEBUG
 932                 printf("Nothing to copy to new block!\n");
 933 #endif
 934                 retval = EXT2_ET_CANT_SPLIT_EXTENT;
 935                 goto done;
 936         }
 937
 938         /* first we need a new block, or can do nothing. */
 939         block_buf = malloc(handle->fs->blocksize);
 940         if (!block_buf) {
 941                 retval = ENOMEM;
 942                 goto done;
 943         }
 944
 945         if (!goal_blk) {
 946                 dgrp_t  group = ext2fs_group_of_ino(handle->fs, handle->ino);
 947                 __u8    log_flex = handle->fs->super->s_log_groups_per_flex;
 948
 949                 if (log_flex)
 950                         group = group & ~((1 << (log_flex)) - 1);
 951                 goal_blk = ext2fs_group_first_block2(handle->fs, group);
 952         }
 953         retval = ext2fs_alloc_block2(handle->fs, goal_blk, block_buf,
 954                                     &new_node_pblk);
 955         if (retval)
 956                 goto done;
 957
 958 #ifdef DEBUG
 959         printf("will copy to new node at block %lu\n",
 960                (unsigned long) new_node_pblk);
 961 #endif
 962
 963         /* Copy data into new block buffer */
 964         /* First the header for the new block... */
 965         neweh = (struct ext3_extent_header *) block_buf;
 966         memcpy(neweh, eh, sizeof(struct ext3_extent_header));
 967         neweh->eh_entries = ext2fs_cpu_to_le16(tocopy);
 968         neweh->eh_max = ext2fs_cpu_to_le16((handle->fs->blocksize -
 969                          sizeof(struct ext3_extent_header)) /
 970                                 sizeof(struct ext3_extent));
 971
 972         /* then the entries for the new block... */
 973         memcpy(EXT_FIRST_INDEX(neweh),
 974                 EXT_FIRST_INDEX(eh) +
 975                         (ext2fs_le16_to_cpu(eh->eh_entries) - tocopy),
 976                 sizeof(struct ext3_extent_idx) * tocopy);
 977
 978         new_node_start = ext2fs_le32_to_cpu(EXT_FIRST_INDEX(neweh)->ei_block);
 979
 980         /* then update the checksum */
 981         retval = ext2fs_extent_block_csum_set(handle->fs, handle->ino, neweh);
 982         if (retval)
 983                 goto done;
 984
 985         /* ...and write the new node block out to disk. */
 986         retval = io_channel_write_blk64(handle->fs->io, new_node_pblk, 1,
 987                                         block_buf);
 988
 989         if (retval)
 990                 goto done;
 991
 992         /* OK! we've created the new node; now adjust the tree */
 993
 994         /* current path now has fewer active entries, we copied some out */
 995         if (handle->level == 0) {
 996                 memcpy(newpath, path,
 997                        sizeof(struct extent_path) * handle->max_paths);
 998                 handle->path = newpath;
 999                 newpath = path;
1000                 path = handle->path;
1001                 path->entries = 1;
1002                 path->left = path->max_entries - 1;
1003                 handle->max_depth++;
1004                 handle->max_paths++;
1005                 eh->eh_depth = ext2fs_cpu_to_le16(handle->max_depth);
1006         } else {
1007                 path->entries -= tocopy;
1008                 path->left -= tocopy;
1009         }
1010
1011         eh->eh_entries = ext2fs_cpu_to_le16(path->entries);
1012         /* this writes out the node, incl. the modified header */
1013         retval = update_path(handle);
1014         if (retval)
1015                 goto done;
1016
1017         /* now go up and insert/replace index for new node we created */
1018         if (new_root) {
1019                 retval = ext2fs_extent_get(handle, EXT2_EXTENT_FIRST_SIB, &extent);
1020                 if (retval)
1021                         goto done;
1022
1023                 extent.e_lblk = new_node_start;
1024                 extent.e_pblk = new_node_pblk;
1025                 extent.e_len = handle->path[0].end_blk - extent.e_lblk;
1026                 retval = ext2fs_extent_replace(handle, 0, &extent);
1027                 if (retval)
1028                         goto done;
1029         } else {
1030                 __u32 new_node_length;
1031
1032                 retval = ext2fs_extent_get(handle, EXT2_EXTENT_UP, &extent);
1033                 /* will insert after this one; it's length is shorter now */
1034                 new_node_length = new_node_start - extent.e_lblk;
1035                 extent.e_len -= new_node_length;
1036                 retval = ext2fs_extent_replace(handle, 0, &extent);
1037                 if (retval)
1038                         goto done;
1039
1040                 /* now set up the new extent and insert it */
1041                 extent.e_lblk = new_node_start;
1042                 extent.e_pblk = new_node_pblk;
1043                 extent.e_len = new_node_length;
1044                 retval = ext2fs_extent_insert(handle, EXT2_EXTENT_INSERT_AFTER, &extent);
1045                 if (retval)
1046                         goto done;
1047         }
1048
1049         /* get handle back to our original position */
1050         retval = ext2fs_extent_goto2(handle, orig_height, orig_lblk);
1051         if (retval)
1052                 goto done;
1053
1054         /* new node hooked in, so update inode block count (do this here?) */
1055         handle->inode->i_blocks += (handle->fs->blocksize *
1056                                     EXT2FS_CLUSTER_RATIO(handle->fs)) / 512;
1057         retval = ext2fs_write_inode(handle->fs, handle->ino,
1058                                     handle->inode);
1059         if (retval)
1060                 goto done;
1061
1062 done:
1063         if (newpath)
1064                 ext2fs_free_mem(&newpath);
1065         free(block_buf);
1066
1067         return retval;
1068 }
1069
1070 errcode_t ext2fs_extent_insert(ext2_extent_handle_t handle, int flags,
1071                                       struct ext2fs_extent *extent)
1072 {
1073         struct extent_path              *path;
1074         struct ext3_extent_idx          *ix;
1075         struct ext3_extent_header       *eh;
1076         errcode_t                       retval;
1077
1078         EXT2_CHECK_MAGIC(handle, EXT2_ET_MAGIC_EXTENT_HANDLE);
1079
1080         if (!(handle->fs->flags & EXT2_FLAG_RW))
1081                 return EXT2_ET_RO_FILSYS;
1082
1083         if (!handle->path)
1084                 return EXT2_ET_NO_CURRENT_NODE;
1085
1086 #ifdef DEBUG
1087         printf("extent insert: %u ", handle->ino);
1088         dbg_print_extent(0, extent);
1089 #endif
1090
1091         path = handle->path + handle->level;
1092
1093         if (path->entries >= path->max_entries) {
1094                 if (flags & EXT2_EXTENT_INSERT_NOSPLIT) {
1095                         return EXT2_ET_CANT_INSERT_EXTENT;
1096                 } else {
1097 #ifdef DEBUG
1098                         printf("node full (level %d) - splitting\n",
1099                                    handle->level);
1100 #endif
1101                         retval = ext2fs_extent_node_split(handle);
1102                         if (retval)
1103                                 return retval;
1104                         path = handle->path + handle->level;
1105                 }
1106         }
1107
1108         eh = (struct ext3_extent_header *) path->buf;
1109         if (path->curr) {
1110                 ix = path->curr;
1111                 if (flags & EXT2_EXTENT_INSERT_AFTER) {
1112                         ix++;
1113                         path->left--;
1114                 }
1115         } else {
1116                 ix = EXT_FIRST_INDEX(eh);
1117                 path->left = -1;
1118         }
1119
1120         path->curr = ix;
1121
1122         if (path->left >= 0)
1123                 memmove(ix + 1, ix,
1124                         (path->left+1) * sizeof(struct ext3_extent_idx));
1125         path->left++;
1126         path->entries++;
1127
1128         eh = (struct ext3_extent_header *) path->buf;
1129         eh->eh_entries = ext2fs_cpu_to_le16(path->entries);
1130
1131         retval = ext2fs_extent_replace(handle, 0, extent);
1132         if (retval)
1133                 goto errout;
1134
1135         retval = update_path(handle);
1136         if (retval)
1137                 goto errout;
1138
1139         return 0;
1140
1141 errout:
1142         ext2fs_extent_delete(handle, 0);
1143         return retval;
1144 }
1145
1146 /*
1147  * Sets the physical block for a logical file block in the extent tree.
1148  *
1149  * May: map unmapped, unmap mapped, or remap mapped blocks.
1150  *
1151  * Mapping an unmapped block adds a single-block extent.
1152  *
1153  * Unmapping first or last block modifies extent in-place
1154  *  - But may need to fix parent's starts too in first-block case
1155  *
1156  * Mapping any unmapped block requires adding a (single-block) extent
1157  * and inserting into proper point in tree.
1158  *
1159  * Modifying (unmapping or remapping) a block in the middle
1160  * of an extent requires splitting the extent.
1161  *  - Remapping case requires new single-block extent.
1162  *
1163  * Remapping first or last block adds an extent.
1164  *
1165  * We really need extent adding to be smart about merging.
1166  */
1167
1168 errcode_t ext2fs_extent_set_bmap(ext2_extent_handle_t handle,
1169                                  blk64_t logical, blk64_t physical, int flags)
1170 {
1171         errcode_t               ec, retval = 0;
1172         int                     mapped = 1; /* logical is mapped? */
1173         int                     orig_height;
1174         int                     extent_uninit = 0;
1175         int                     prev_uninit = 0;
1176         int                     next_uninit = 0;
1177         int                     new_uninit = 0;
1178         int                     max_len = EXT_INIT_MAX_LEN;
1179         int                     has_prev, has_next;
1180         blk64_t                 orig_lblk;
1181         struct extent_path      *path;
1182         struct ext2fs_extent    extent, next_extent, prev_extent;
1183         struct ext2fs_extent    newextent;
1184         struct ext2_extent_info info;
1185
1186         EXT2_CHECK_MAGIC(handle, EXT2_ET_MAGIC_EXTENT_HANDLE);
1187
1188 #ifdef DEBUG
1189         printf("set_bmap ino %u log %lld phys %lld flags %d\n",
1190                handle->ino, logical, physical, flags);
1191 #endif
1192
1193         if (!(handle->fs->flags & EXT2_FLAG_RW))
1194                 return EXT2_ET_RO_FILSYS;
1195
1196         if (!handle->path)
1197                 return EXT2_ET_NO_CURRENT_NODE;
1198
1199         path = handle->path + handle->level;
1200
1201         if (flags & EXT2_EXTENT_SET_BMAP_UNINIT) {
1202                 new_uninit = 1;
1203                 max_len = EXT_UNINIT_MAX_LEN;
1204         }
1205
1206         /* if (re)mapping, set up new extent to insert */
1207         if (physical) {
1208                 newextent.e_len = 1;
1209                 newextent.e_pblk = physical;
1210                 newextent.e_lblk = logical;
1211                 newextent.e_flags = EXT2_EXTENT_FLAGS_LEAF;
1212                 if (new_uninit)
1213                         newextent.e_flags |= EXT2_EXTENT_FLAGS_UNINIT;
1214         }
1215
1216         /* special case if the extent tree is completely empty */
1217         if ((handle->max_depth == 0) && (path->entries == 0)) {
1218                 retval = ext2fs_extent_insert(handle, 0, &newextent);
1219                 return retval;
1220         }
1221
1222         /* save our original location in the extent tree */
1223         if ((retval = ext2fs_extent_get(handle, EXT2_EXTENT_CURRENT,
1224                                         &extent))) {
1225                 if (retval != EXT2_ET_NO_CURRENT_NODE)
1226                         return retval;
1227                 memset(&extent, 0, sizeof(extent));
1228         }
1229         if ((retval = ext2fs_extent_get_info(handle, &info)))
1230                 return retval;
1231         orig_height = info.max_depth - info.curr_level;
1232         orig_lblk = extent.e_lblk;
1233
1234         /* go to the logical spot we want to (re/un)map */
1235         retval = ext2fs_extent_goto(handle, logical);
1236         if (retval) {
1237                 if (retval == EXT2_ET_EXTENT_NOT_FOUND) {
1238                         retval = 0;
1239                         mapped = 0;
1240                         if (!physical) {
1241 #ifdef DEBUG
1242                                 printf("block %llu already unmapped\n",
1243                                         logical);
1244 #endif
1245                                 goto done;
1246                         }
1247                 } else
1248                         goto done;
1249         }
1250
1251         /*
1252          * This may be the extent *before* the requested logical,
1253          * if it's currently unmapped.
1254          *
1255          * Get the previous and next leaf extents, if they are present.
1256          */
1257         retval = ext2fs_extent_get(handle, EXT2_EXTENT_CURRENT, &extent);
1258         if (retval)
1259                 goto done;
1260         if (extent.e_flags & EXT2_EXTENT_FLAGS_UNINIT)
1261                 extent_uninit = 1;
1262         retval = ext2fs_extent_get(handle, EXT2_EXTENT_NEXT_LEAF, &next_extent);
1263         if (retval) {
1264                 has_next = 0;
1265                 if (retval != EXT2_ET_EXTENT_NO_NEXT)
1266                         goto done;
1267         } else {
1268                 dbg_print_extent("set_bmap: next_extent",
1269                                  &next_extent);
1270                 has_next = 1;
1271                 if (next_extent.e_flags & EXT2_EXTENT_FLAGS_UNINIT)
1272                         next_uninit = 1;
1273         }
1274         retval = ext2fs_extent_goto(handle, logical);
1275         if (retval && retval != EXT2_ET_EXTENT_NOT_FOUND)
1276                 goto done;
1277         retval = ext2fs_extent_get(handle, EXT2_EXTENT_PREV_LEAF, &prev_extent);
1278         if (retval) {
1279                 has_prev = 0;
1280                 if (retval != EXT2_ET_EXTENT_NO_PREV)
1281                         goto done;
1282         } else {
1283                 has_prev = 1;
1284                 dbg_print_extent("set_bmap: prev_extent",
1285                                  &prev_extent);
1286                 if (prev_extent.e_flags & EXT2_EXTENT_FLAGS_UNINIT)
1287                         prev_uninit = 1;
1288         }
1289         retval = ext2fs_extent_goto(handle, logical);
1290         if (retval && retval != EXT2_ET_EXTENT_NOT_FOUND)
1291                 goto done;
1292
1293         /* check if already pointing to the requested physical */
1294         if (mapped && (new_uninit == extent_uninit) &&
1295             (extent.e_pblk + (logical - extent.e_lblk) == physical)) {
1296 #ifdef DEBUG
1297                 printf("physical block (at %llu) unchanged\n", logical);
1298 #endif
1299                 goto done;
1300         }
1301
1302         if (!mapped) {
1303 #ifdef DEBUG
1304                 printf("mapping unmapped logical block %llu\n", logical);
1305 #endif
1306                 if ((logical == extent.e_lblk + extent.e_len) &&
1307                     (physical == extent.e_pblk + extent.e_len) &&
1308                     (new_uninit == extent_uninit) &&
1309                     ((int) extent.e_len < max_len-1)) {
1310                         extent.e_len++;
1311                         retval = ext2fs_extent_replace(handle, 0, &extent);
1312                 } else if ((logical == extent.e_lblk - 1) &&
1313                            (physical == extent.e_pblk - 1) &&
1314                            (new_uninit == extent_uninit) &&
1315                            ((int) extent.e_len < max_len - 1)) {
1316                         extent.e_len++;
1317                         extent.e_lblk--;
1318                         extent.e_pblk--;
1319                         retval = ext2fs_extent_replace(handle, 0, &extent);
1320                 } else if (has_next &&
1321                            (logical == next_extent.e_lblk - 1) &&
1322                            (physical == next_extent.e_pblk - 1) &&
1323                            (new_uninit == next_uninit) &&
1324                            ((int) next_extent.e_len < max_len - 1)) {
1325                         retval = ext2fs_extent_get(handle,
1326                                                    EXT2_EXTENT_NEXT_LEAF,
1327                                                    &next_extent);
1328                         if (retval)
1329                                 goto done;
1330                         next_extent.e_len++;
1331                         next_extent.e_lblk--;
1332                         next_extent.e_pblk--;
1333                         retval = ext2fs_extent_replace(handle, 0, &next_extent);
1334                 } else if (logical < extent.e_lblk)
1335                         retval = ext2fs_extent_insert(handle, 0, &newextent);
1336                 else
1337                         retval = ext2fs_extent_insert(handle,
1338                                       EXT2_EXTENT_INSERT_AFTER, &newextent);
1339                 if (retval)
1340                         goto done;
1341                 retval = ext2fs_extent_fix_parents(handle);
1342                 if (retval)
1343                         goto done;
1344         } else if ((logical == extent.e_lblk) && (extent.e_len == 1))  {
1345 #ifdef DEBUG
1346                 printf("(re/un)mapping only block in extent\n");
1347 #endif
1348                 if (physical) {
1349                         retval = ext2fs_extent_replace(handle, 0, &newextent);
1350                 } else {
1351                         retval = ext2fs_extent_delete(handle, 0);
1352                         if (retval)
1353                                 goto done;
1354                         ec = ext2fs_extent_fix_parents(handle);
1355                         if (ec != EXT2_ET_NO_CURRENT_NODE)
1356                                 retval = ec;
1357                 }
1358
1359                 if (retval)
1360                         goto done;
1361         } else if (logical == extent.e_lblk + extent.e_len - 1)  {
1362 #ifdef DEBUG
1363                 printf("(re/un)mapping last block in extent\n");
1364 #endif
1365                 if (physical) {
1366                         if (has_next &&
1367                             (logical == (next_extent.e_lblk - 1)) &&
1368                             (physical == (next_extent.e_pblk - 1)) &&
1369                             (new_uninit == next_uninit) &&
1370                             ((int) next_extent.e_len < max_len - 1)) {
1371                                 retval = ext2fs_extent_get(handle,
1372                                         EXT2_EXTENT_NEXT_LEAF, &next_extent);
1373                                 if (retval)
1374                                         goto done;
1375                                 next_extent.e_len++;
1376                                 next_extent.e_lblk--;
1377                                 next_extent.e_pblk--;
1378                                 retval = ext2fs_extent_replace(handle, 0,
1379                                                                &next_extent);
1380                                 if (retval)
1381                                         goto done;
1382                                 retval = ext2fs_extent_fix_parents(handle);
1383                                 if (retval)
1384                                         goto done;
1385                         } else
1386                                 retval = ext2fs_extent_insert(handle,
1387                                       EXT2_EXTENT_INSERT_AFTER, &newextent);
1388                         if (retval)
1389                                 goto done;
1390                         /* Now pointing at inserted extent; move back to prev */
1391                         retval = ext2fs_extent_get(handle,
1392                                                    EXT2_EXTENT_PREV_LEAF,
1393                                                    &extent);
1394                         if (retval)
1395                                 goto done;
1396                 }
1397                 extent.e_len--;
1398                 retval = ext2fs_extent_replace(handle, 0, &extent);
1399                 if (retval)
1400                         goto done;
1401         } else if (logical == extent.e_lblk) {
1402 #ifdef DEBUG
1403                 printf("(re/un)mapping first block in extent\n");
1404 #endif
1405                 if (physical) {
1406                         if (has_prev &&
1407                             (logical == (prev_extent.e_lblk +
1408                                          prev_extent.e_len)) &&
1409                             (physical == (prev_extent.e_pblk +
1410                                           prev_extent.e_len)) &&
1411                             (new_uninit == prev_uninit) &&
1412                             ((int) prev_extent.e_len < max_len-1)) {
1413                                 retval = ext2fs_extent_get(handle,
1414                                         EXT2_EXTENT_PREV_LEAF, &prev_extent);
1415                                 if (retval)
1416                                         goto done;
1417                                 prev_extent.e_len++;
1418                                 retval = ext2fs_extent_replace(handle, 0,
1419                                                                &prev_extent);
1420                         } else
1421                                 retval = ext2fs_extent_insert(handle,
1422                                                               0, &newextent);
1423                         if (retval)
1424                                 goto done;
1425                         retval = ext2fs_extent_get(handle,
1426                                                    EXT2_EXTENT_NEXT_LEAF,
1427                                                    &extent);
1428                         if (retval)
1429                                 goto done;
1430                 }
1431                 extent.e_pblk++;
1432                 extent.e_lblk++;
1433                 extent.e_len--;
1434                 retval = ext2fs_extent_replace(handle, 0, &extent);
1435                 if (retval)
1436                         goto done;
1437                 retval = ext2fs_extent_fix_parents(handle);
1438                 if (retval)
1439                         goto done;
1440         } else {
1441                 __u32   orig_length;
1442                 blk64_t orig_lblk;
1443                 struct ext2fs_extent orig_extent;
1444                 errcode_t r2;
1445
1446 #ifdef DEBUG
1447                 printf("(re/un)mapping in middle of extent\n");
1448 #endif
1449                 /* need to split this extent; later */
1450                 orig_lblk = extent.e_lblk;
1451                 orig_length = extent.e_len;
1452                 orig_extent = extent;
1453
1454                 /* shorten pre-split extent */
1455                 extent.e_len = (logical - extent.e_lblk);
1456                 retval = ext2fs_extent_replace(handle, 0, &extent);
1457                 if (retval)
1458                         goto done;
1459                 /* insert our new extent, if any */
1460                 if (physical) {
1461                         /* insert new extent after current */
1462                         retval = ext2fs_extent_insert(handle,
1463                                         EXT2_EXTENT_INSERT_AFTER, &newextent);
1464                         if (retval) {
1465                                 r2 = ext2fs_extent_goto(handle, orig_lblk);
1466                                 if (r2 == 0)
1467                                         ext2fs_extent_replace(handle, 0,
1468                                                               &orig_extent);
1469                                 goto done;
1470                         }
1471                 }
1472                 /* add post-split extent */
1473                 extent.e_pblk += extent.e_len + 1;
1474                 extent.e_lblk += extent.e_len + 1;
1475                 extent.e_len = orig_length - extent.e_len - 1;
1476                 retval = ext2fs_extent_insert(handle,
1477                                 EXT2_EXTENT_INSERT_AFTER, &extent);
1478                 if (retval) {
1479                         if (physical) {
1480                                 r2 = ext2fs_extent_goto(handle,
1481                                                         newextent.e_lblk);
1482                                 if (r2 == 0)
1483                                         ext2fs_extent_delete(handle, 0);
1484                         }
1485                         r2 = ext2fs_extent_goto(handle, orig_lblk);
1486                         if (r2 == 0)
1487                                 ext2fs_extent_replace(handle, 0, &orig_extent);
1488                         goto done;
1489                 }
1490         }
1491
1492 done:
1493         /* get handle back to its position */
1494         if (orig_height > handle->max_depth)
1495                 orig_height = handle->max_depth; /* In case we shortened the tree */
1496         ext2fs_extent_goto2(handle, orig_height, orig_lblk);
1497         return retval;
1498 }
1499
1500 errcode_t ext2fs_extent_delete(ext2_extent_handle_t handle, int flags)
1501 {
1502         struct extent_path              *path;
1503         char                            *cp;
1504         struct ext3_extent_header       *eh;
1505         errcode_t                       retval = 0;
1506
1507         EXT2_CHECK_MAGIC(handle, EXT2_ET_MAGIC_EXTENT_HANDLE);
1508
1509         if (!(handle->fs->flags & EXT2_FLAG_RW))
1510                 return EXT2_ET_RO_FILSYS;
1511
1512         if (!handle->path)
1513                 return EXT2_ET_NO_CURRENT_NODE;
1514
1515 #ifdef DEBUG
1516         {
1517                 struct ext2fs_extent    extent;
1518
1519                 retval = ext2fs_extent_get(handle, EXT2_EXTENT_CURRENT,
1520                                            &extent);
1521                 if (retval == 0) {
1522                         printf("extent delete %u ", handle->ino);
1523                         dbg_print_extent(0, &extent);
1524                 }
1525         }
1526 #endif
1527
1528         path = handle->path + handle->level;
1529         if (!path->curr)
1530                 return EXT2_ET_NO_CURRENT_NODE;
1531
1532         cp = path->curr;
1533
1534         if (path->left) {
1535                 memmove(cp, cp + sizeof(struct ext3_extent_idx),
1536                         path->left * sizeof(struct ext3_extent_idx));
1537                 path->left--;
1538         } else {
1539                 struct ext3_extent_idx  *ix = path->curr;
1540                 ix--;
1541                 path->curr = ix;
1542         }
1543         if (--path->entries == 0)
1544                 path->curr = 0;
1545
1546         /* if non-root node has no entries left, remove it & parent ptr to it */
1547         if (path->entries == 0 && handle->level) {
1548                 if (!(flags & EXT2_EXTENT_DELETE_KEEP_EMPTY)) {
1549                         struct ext2fs_extent    extent;
1550
1551                         retval = ext2fs_extent_get(handle, EXT2_EXTENT_UP,
1552                                                                 &extent);
1553                         if (retval)
1554                                 return retval;
1555
1556                         retval = ext2fs_extent_delete(handle, flags);
1557                         handle->inode->i_blocks -=
1558                                 (handle->fs->blocksize *
1559                                  EXT2FS_CLUSTER_RATIO(handle->fs)) / 512;
1560                         retval = ext2fs_write_inode(handle->fs, handle->ino,
1561                                                     handle->inode);
1562                         ext2fs_block_alloc_stats2(handle->fs,
1563                                                   extent.e_pblk, -1);
1564                 }
1565         } else {
1566                 eh = (struct ext3_extent_header *) path->buf;
1567                 eh->eh_entries = ext2fs_cpu_to_le16(path->entries);
1568                 if ((path->entries == 0) && (handle->level == 0))
1569                         eh->eh_depth = handle->max_depth = 0;
1570                 retval = update_path(handle);
1571         }
1572         return retval;
1573 }
1574
1575 errcode_t ext2fs_extent_get_info(ext2_extent_handle_t handle,
1576                                  struct ext2_extent_info *info)
1577 {
1578         struct extent_path              *path;
1579
1580         EXT2_CHECK_MAGIC(handle, EXT2_ET_MAGIC_EXTENT_HANDLE);
1581
1582         memset(info, 0, sizeof(struct ext2_extent_info));
1583
1584         path = handle->path + handle->level;
1585         if (path) {
1586                 if (path->curr)
1587                         info->curr_entry = ((char *) path->curr - path->buf) /
1588                                 sizeof(struct ext3_extent_idx);
1589                 else
1590                         info->curr_entry = 0;
1591                 info->num_entries = path->entries;
1592                 info->max_entries = path->max_entries;
1593                 info->bytes_avail = (path->max_entries - path->entries) *
1594                         sizeof(struct ext3_extent);
1595         }
1596
1597         info->curr_level = handle->level;
1598         info->max_depth = handle->max_depth;
1599         info->max_lblk = ((__u64) 1 << 32) - 1;
1600         info->max_pblk = ((__u64) 1 << 48) - 1;
1601         info->max_len = (1UL << 15);
1602         info->max_uninit_len = (1UL << 15) - 1;
1603
1604         return 0;
1605 }
1606
1607 #ifdef DEBUG
1608 /*
1609  * Override debugfs's prompt
1610  */
1611 const char *debug_prog_name = "tst_extents";
1612
1613 #endif
1614