e2fsprogs/ext2fs/inode.c

   1 /*
   2  * inode.c --- utility routines to read and write inodes
   3  *
   4  * Copyright (C) 1993, 1994, 1995, 1996, 1997 Theodore Ts'o.
   5  *
   6  * %Begin-Header%
   7  * This file may be redistributed under the terms of the GNU Public
   8  * License.
   9  * %End-Header%
  10  */
  11
  12 #include <stdio.h>
  13 #include <string.h>
  14 #if HAVE_UNISTD_H
  15 #include <unistd.h>
  16 #endif
  17 #if HAVE_ERRNO_H
  18 #include <errno.h>
  19 #endif
  20 #if HAVE_SYS_STAT_H
  21 #include <sys/stat.h>
  22 #endif
  23 #if HAVE_SYS_TYPES_H
  24 #include <sys/types.h>
  25 #endif
  26
  27 #include "ext2_fs.h"
  28 #include "ext2fsP.h"
  29 #include "e2image.h"
  30
  31 struct ext2_struct_inode_scan {
  32         errcode_t               magic;
  33         ext2_filsys             fs;
  34         ext2_ino_t              current_inode;
  35         blk_t                   current_block;
  36         dgrp_t                  current_group;
  37         ext2_ino_t              inodes_left;
  38         blk_t                   blocks_left;
  39         dgrp_t                  groups_left;
  40         blk_t                   inode_buffer_blocks;
  41         char *                  inode_buffer;
  42         int                     inode_size;
  43         char *                  ptr;
  44         int                     bytes_left;
  45         char                    *temp_buffer;
  46         errcode_t               (*done_group)(ext2_filsys fs,
  47                                               dgrp_t group,
  48                                               void * priv_data);
  49         void *                  done_group_data;
  50         int                     bad_block_ptr;
  51         int                     scan_flags;
  52         int                     reserved[6];
  53 };
  54
  55 /*
  56  * This routine flushes the icache, if it exists.
  57  */
  58 errcode_t ext2fs_flush_icache(ext2_filsys fs)
  59 {
  60         int     i;
  61
  62         if (!fs->icache)
  63                 return 0;
  64
  65         for (i=0; i < fs->icache->cache_size; i++)
  66                 fs->icache->cache[i].ino = 0;
  67
  68         fs->icache->buffer_blk = 0;
  69         return 0;
  70 }
  71
  72 static errcode_t create_icache(ext2_filsys fs)
  73 {
  74         errcode_t       retval;
  75
  76         if (fs->icache)
  77                 return 0;
  78         retval = ext2fs_get_mem(sizeof(struct ext2_inode_cache), &fs->icache);
  79         if (retval)
  80                 return retval;
  81
  82         memset(fs->icache, 0, sizeof(struct ext2_inode_cache));
  83         retval = ext2fs_get_mem(fs->blocksize, &fs->icache->buffer);
  84         if (retval) {
  85                 ext2fs_free_mem(&fs->icache);
  86                 return retval;
  87         }
  88         fs->icache->buffer_blk = 0;
  89         fs->icache->cache_last = -1;
  90         fs->icache->cache_size = 4;
  91         fs->icache->refcount = 1;
  92         retval = ext2fs_get_mem(sizeof(struct ext2_inode_cache_ent)
  93                                 * fs->icache->cache_size,
  94                                 &fs->icache->cache);
  95         if (retval) {
  96                 ext2fs_free_mem(&fs->icache->buffer);
  97                 ext2fs_free_mem(&fs->icache);
  98                 return retval;
  99         }
 100         ext2fs_flush_icache(fs);
 101         return 0;
 102 }
 103
 104 errcode_t ext2fs_open_inode_scan(ext2_filsys fs, int buffer_blocks,
 105                                  ext2_inode_scan *ret_scan)
 106 {
 107         ext2_inode_scan scan;
 108         errcode_t       retval;
 109         errcode_t (*save_get_blocks)(ext2_filsys f, ext2_ino_t ino, blk_t *blocks);
 110
 111         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 112
 113         /*
 114          * If fs->badblocks isn't set, then set it --- since the inode
 115          * scanning functions require it.
 116          */
 117         if (fs->badblocks == 0) {
 118                 /*
 119                  * Temporarly save fs->get_blocks and set it to zero,
 120                  * for compatibility with old e2fsck's.
 121                  */
 122                 save_get_blocks = fs->get_blocks;
 123                 fs->get_blocks = 0;
 124                 retval = ext2fs_read_bb_inode(fs, &fs->badblocks);
 125                 if (retval) {
 126                         ext2fs_badblocks_list_free(fs->badblocks);
 127                         fs->badblocks = 0;
 128                 }
 129                 fs->get_blocks = save_get_blocks;
 130         }
 131
 132         retval = ext2fs_get_mem(sizeof(struct ext2_struct_inode_scan), &scan);
 133         if (retval)
 134                 return retval;
 135         memset(scan, 0, sizeof(struct ext2_struct_inode_scan));
 136
 137         scan->magic = EXT2_ET_MAGIC_INODE_SCAN;
 138         scan->fs = fs;
 139         scan->inode_size = EXT2_INODE_SIZE(fs->super);
 140         scan->bytes_left = 0;
 141         scan->current_group = 0;
 142         scan->groups_left = fs->group_desc_count - 1;
 143         scan->inode_buffer_blocks = buffer_blocks ? buffer_blocks : 8;
 144         scan->current_block = scan->fs->
 145                 group_desc[scan->current_group].bg_inode_table;
 146         scan->inodes_left = EXT2_INODES_PER_GROUP(scan->fs->super);
 147         scan->blocks_left = scan->fs->inode_blocks_per_group;
 148         retval = ext2fs_get_mem((size_t) (scan->inode_buffer_blocks *
 149                                           fs->blocksize),
 150                                 &scan->inode_buffer);
 151         scan->done_group = 0;
 152         scan->done_group_data = 0;
 153         scan->bad_block_ptr = 0;
 154         if (retval) {
 155                 ext2fs_free_mem(&scan);
 156                 return retval;
 157         }
 158         retval = ext2fs_get_mem(scan->inode_size, &scan->temp_buffer);
 159         if (retval) {
 160                 ext2fs_free_mem(&scan->inode_buffer);
 161                 ext2fs_free_mem(&scan);
 162                 return retval;
 163         }
 164         if (scan->fs->badblocks && scan->fs->badblocks->num)
 165                 scan->scan_flags |= EXT2_SF_CHK_BADBLOCKS;
 166         *ret_scan = scan;
 167         return 0;
 168 }
 169
 170 void ext2fs_close_inode_scan(ext2_inode_scan scan)
 171 {
 172         if (!scan || (scan->magic != EXT2_ET_MAGIC_INODE_SCAN))
 173                 return;
 174
 175         ext2fs_free_mem(&scan->inode_buffer);
 176         scan->inode_buffer = NULL;
 177         ext2fs_free_mem(&scan->temp_buffer);
 178         scan->temp_buffer = NULL;
 179         ext2fs_free_mem(&scan);
 180         return;
 181 }
 182
 183 void ext2fs_set_inode_callback(ext2_inode_scan scan,
 184                                errcode_t (*done_group)(ext2_filsys fs,
 185                                                        dgrp_t group,
 186                                                        void * priv_data),
 187                                void *done_group_data)
 188 {
 189         if (!scan || (scan->magic != EXT2_ET_MAGIC_INODE_SCAN))
 190                 return;
 191
 192         scan->done_group = done_group;
 193         scan->done_group_data = done_group_data;
 194 }
 195
 196 int ext2fs_inode_scan_flags(ext2_inode_scan scan, int set_flags,
 197                             int clear_flags)
 198 {
 199         int     old_flags;
 200
 201         if (!scan || (scan->magic != EXT2_ET_MAGIC_INODE_SCAN))
 202                 return 0;
 203
 204         old_flags = scan->scan_flags;
 205         scan->scan_flags &= ~clear_flags;
 206         scan->scan_flags |= set_flags;
 207         return old_flags;
 208 }
 209
 210 /*
 211  * This function is called by ext2fs_get_next_inode when it needs to
 212  * get ready to read in a new blockgroup.
 213  */
 214 static errcode_t get_next_blockgroup(ext2_inode_scan scan)
 215 {
 216         scan->current_group++;
 217         scan->groups_left--;
 218
 219         scan->current_block = scan->fs->
 220                 group_desc[scan->current_group].bg_inode_table;
 221
 222         scan->current_inode = scan->current_group *
 223                 EXT2_INODES_PER_GROUP(scan->fs->super);
 224
 225         scan->bytes_left = 0;
 226         scan->inodes_left = EXT2_INODES_PER_GROUP(scan->fs->super);
 227         scan->blocks_left = scan->fs->inode_blocks_per_group;
 228         return 0;
 229 }
 230
 231 errcode_t ext2fs_inode_scan_goto_blockgroup(ext2_inode_scan scan,
 232                                             int group)
 233 {
 234         scan->current_group = group - 1;
 235         scan->groups_left = scan->fs->group_desc_count - group;
 236         return get_next_blockgroup(scan);
 237 }
 238
 239 /*
 240  * This function is called by get_next_blocks() to check for bad
 241  * blocks in the inode table.
 242  *
 243  * This function assumes that badblocks_list->list is sorted in
 244  * increasing order.
 245  */
 246 static errcode_t check_for_inode_bad_blocks(ext2_inode_scan scan,
 247                                             blk_t *num_blocks)
 248 {
 249         blk_t   blk = scan->current_block;
 250         badblocks_list  bb = scan->fs->badblocks;
 251
 252         /*
 253          * If the inode table is missing, then obviously there are no
 254          * bad blocks.  :-)
 255          */
 256         if (blk == 0)
 257                 return 0;
 258
 259         /*
 260          * If the current block is greater than the bad block listed
 261          * in the bad block list, then advance the pointer until this
 262          * is no longer the case.  If we run out of bad blocks, then
 263          * we don't need to do any more checking!
 264          */
 265         while (blk > bb->list[scan->bad_block_ptr]) {
 266                 if (++scan->bad_block_ptr >= bb->num) {
 267                         scan->scan_flags &= ~EXT2_SF_CHK_BADBLOCKS;
 268                         return 0;
 269                 }
 270         }
 271
 272         /*
 273          * If the current block is equal to the bad block listed in
 274          * the bad block list, then handle that one block specially.
 275          * (We could try to handle runs of bad blocks, but that
 276          * only increases CPU efficiency by a small amount, at the
 277          * expense of a huge expense of code complexity, and for an
 278          * uncommon case at that.)
 279          */
 280         if (blk == bb->list[scan->bad_block_ptr]) {
 281                 scan->scan_flags |= EXT2_SF_BAD_INODE_BLK;
 282                 *num_blocks = 1;
 283                 if (++scan->bad_block_ptr >= bb->num)
 284                         scan->scan_flags &= ~EXT2_SF_CHK_BADBLOCKS;
 285                 return 0;
 286         }
 287
 288         /*
 289          * If there is a bad block in the range that we're about to
 290          * read in, adjust the number of blocks to read so that we we
 291          * don't read in the bad block.  (Then the next block to read
 292          * will be the bad block, which is handled in the above case.)
 293          */
 294         if ((blk + *num_blocks) > bb->list[scan->bad_block_ptr])
 295                 *num_blocks = (int) (bb->list[scan->bad_block_ptr] - blk);
 296
 297         return 0;
 298 }
 299
 300 /*
 301  * This function is called by ext2fs_get_next_inode when it needs to
 302  * read in more blocks from the current blockgroup's inode table.
 303  */
 304 static errcode_t get_next_blocks(ext2_inode_scan scan)
 305 {
 306         blk_t           num_blocks;
 307         errcode_t       retval;
 308
 309         /*
 310          * Figure out how many blocks to read; we read at most
 311          * inode_buffer_blocks, and perhaps less if there aren't that
 312          * many blocks left to read.
 313          */
 314         num_blocks = scan->inode_buffer_blocks;
 315         if (num_blocks > scan->blocks_left)
 316                 num_blocks = scan->blocks_left;
 317
 318         /*
 319          * If the past block "read" was a bad block, then mark the
 320          * left-over extra bytes as also being bad.
 321          */
 322         if (scan->scan_flags & EXT2_SF_BAD_INODE_BLK) {
 323                 if (scan->bytes_left)
 324                         scan->scan_flags |= EXT2_SF_BAD_EXTRA_BYTES;
 325                 scan->scan_flags &= ~EXT2_SF_BAD_INODE_BLK;
 326         }
 327
 328         /*
 329          * Do inode bad block processing, if necessary.
 330          */
 331         if (scan->scan_flags & EXT2_SF_CHK_BADBLOCKS) {
 332                 retval = check_for_inode_bad_blocks(scan, &num_blocks);
 333                 if (retval)
 334                         return retval;
 335         }
 336
 337         if ((scan->scan_flags & EXT2_SF_BAD_INODE_BLK) ||
 338             (scan->current_block == 0)) {
 339                 memset(scan->inode_buffer, 0,
 340                        (size_t) num_blocks * scan->fs->blocksize);
 341         } else {
 342                 retval = io_channel_read_blk(scan->fs->io,
 343                                              scan->current_block,
 344                                              (int) num_blocks,
 345                                              scan->inode_buffer);
 346                 if (retval)
 347                         return EXT2_ET_NEXT_INODE_READ;
 348         }
 349         scan->ptr = scan->inode_buffer;
 350         scan->bytes_left = num_blocks * scan->fs->blocksize;
 351
 352         scan->blocks_left -= num_blocks;
 353         if (scan->current_block)
 354                 scan->current_block += num_blocks;
 355         return 0;
 356 }
 357
 358 #if 0
 359 /*
 360  * Returns 1 if the entire inode_buffer has a non-zero size and
 361  * contains all zeros.  (Not just deleted inodes, since that means
 362  * that part of the inode table was used at one point; we want all
 363  * zeros, which means that the inode table is pristine.)
 364  */
 365 static inline int is_empty_scan(ext2_inode_scan scan)
 366 {
 367         int     i;
 368
 369         if (scan->bytes_left == 0)
 370                 return 0;
 371
 372         for (i=0; i < scan->bytes_left; i++)
 373                 if (scan->ptr[i])
 374                         return 0;
 375         return 1;
 376 }
 377 #endif
 378
 379 errcode_t ext2fs_get_next_inode_full(ext2_inode_scan scan, ext2_ino_t *ino,
 380                                      struct ext2_inode *inode, int bufsize)
 381 {
 382         errcode_t       retval;
 383         int             extra_bytes = 0;
 384
 385         EXT2_CHECK_MAGIC(scan, EXT2_ET_MAGIC_INODE_SCAN);
 386
 387         /*
 388          * Do we need to start reading a new block group?
 389          */
 390         if (scan->inodes_left <= 0) {
 391         force_new_group:
 392                 if (scan->done_group) {
 393                         retval = (scan->done_group)
 394                                 (scan->fs, scan->current_group,
 395                                  scan->done_group_data);
 396                         if (retval)
 397                                 return retval;
 398                 }
 399                 if (scan->groups_left <= 0) {
 400                         *ino = 0;
 401                         return 0;
 402                 }
 403                 retval = get_next_blockgroup(scan);
 404                 if (retval)
 405                         return retval;
 406         }
 407         /*
 408          * This is done outside the above if statement so that the
 409          * check can be done for block group #0.
 410          */
 411         if (scan->current_block == 0) {
 412                 if (scan->scan_flags & EXT2_SF_SKIP_MISSING_ITABLE) {
 413                         goto force_new_group;
 414                 } else
 415                         return EXT2_ET_MISSING_INODE_TABLE;
 416         }
 417
 418
 419         /*
 420          * Have we run out of space in the inode buffer?  If so, we
 421          * need to read in more blocks.
 422          */
 423         if (scan->bytes_left < scan->inode_size) {
 424                 memcpy(scan->temp_buffer, scan->ptr, scan->bytes_left);
 425                 extra_bytes = scan->bytes_left;
 426
 427                 retval = get_next_blocks(scan);
 428                 if (retval)
 429                         return retval;
 430 #if 0
 431                 /*
 432                  * XXX test  Need check for used inode somehow.
 433                  * (Note: this is hard.)
 434                  */
 435                 if (is_empty_scan(scan))
 436                         goto force_new_group;
 437 #endif
 438         }
 439
 440         retval = 0;
 441         if (extra_bytes) {
 442                 memcpy(scan->temp_buffer+extra_bytes, scan->ptr,
 443                        scan->inode_size - extra_bytes);
 444                 scan->ptr += scan->inode_size - extra_bytes;
 445                 scan->bytes_left -= scan->inode_size - extra_bytes;
 446
 447 #if BB_BIG_ENDIAN
 448                 if ((scan->fs->flags & EXT2_FLAG_SWAP_BYTES) ||
 449                     (scan->fs->flags & EXT2_FLAG_SWAP_BYTES_READ))
 450                         ext2fs_swap_inode_full(scan->fs,
 451                                 (struct ext2_inode_large *) inode,
 452                                 (struct ext2_inode_large *) scan->temp_buffer,
 453                                 0, bufsize);
 454                 else
 455 #endif
 456                         *inode = *((struct ext2_inode *) scan->temp_buffer);
 457                 if (scan->scan_flags & EXT2_SF_BAD_EXTRA_BYTES)
 458                         retval = EXT2_ET_BAD_BLOCK_IN_INODE_TABLE;
 459                 scan->scan_flags &= ~EXT2_SF_BAD_EXTRA_BYTES;
 460         } else {
 461 #if BB_BIG_ENDIAN
 462                 if ((scan->fs->flags & EXT2_FLAG_SWAP_BYTES) ||
 463                     (scan->fs->flags & EXT2_FLAG_SWAP_BYTES_READ))
 464                         ext2fs_swap_inode_full(scan->fs,
 465                                 (struct ext2_inode_large *) inode,
 466                                 (struct ext2_inode_large *) scan->ptr,
 467                                 0, bufsize);
 468                 else
 469 #endif
 470                         memcpy(inode, scan->ptr, bufsize);
 471                 scan->ptr += scan->inode_size;
 472                 scan->bytes_left -= scan->inode_size;
 473                 if (scan->scan_flags & EXT2_SF_BAD_INODE_BLK)
 474                         retval = EXT2_ET_BAD_BLOCK_IN_INODE_TABLE;
 475         }
 476
 477         scan->inodes_left--;
 478         scan->current_inode++;
 479         *ino = scan->current_inode;
 480         return retval;
 481 }
 482
 483 errcode_t ext2fs_get_next_inode(ext2_inode_scan scan, ext2_ino_t *ino,
 484                                 struct ext2_inode *inode)
 485 {
 486         return ext2fs_get_next_inode_full(scan, ino, inode,
 487                                                 sizeof(struct ext2_inode));
 488 }
 489
 490 /*
 491  * Functions to read and write a single inode.
 492  */
 493 errcode_t ext2fs_read_inode_full(ext2_filsys fs, ext2_ino_t ino,
 494                                  struct ext2_inode * inode, int bufsize)
 495 {
 496         unsigned long   group, block, block_nr, offset;
 497         char            *ptr;
 498         errcode_t       retval;
 499         int             clen, i, inodes_per_block, length;
 500         io_channel      io;
 501
 502         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 503
 504         /* Check to see if user has an override function */
 505         if (fs->read_inode) {
 506                 retval = (fs->read_inode)(fs, ino, inode);
 507                 if (retval != EXT2_ET_CALLBACK_NOTHANDLED)
 508                         return retval;
 509         }
 510         /* Create inode cache if not present */
 511         if (!fs->icache) {
 512                 retval = create_icache(fs);
 513                 if (retval)
 514                         return retval;
 515         }
 516         /* Check to see if it's in the inode cache */
 517         if (bufsize == sizeof(struct ext2_inode)) {
 518                 /* only old good inode can be retrieve from the cache */
 519                 for (i=0; i < fs->icache->cache_size; i++) {
 520                         if (fs->icache->cache[i].ino == ino) {
 521                                 *inode = fs->icache->cache[i].inode;
 522                                 return 0;
 523                         }
 524                 }
 525         }
 526         if ((ino == 0) || (ino > fs->super->s_inodes_count))
 527                 return EXT2_ET_BAD_INODE_NUM;
 528         if (fs->flags & EXT2_FLAG_IMAGE_FILE) {
 529                 inodes_per_block = fs->blocksize / EXT2_INODE_SIZE(fs->super);
 530                 block_nr = fs->image_header->offset_inode / fs->blocksize;
 531                 block_nr += (ino - 1) / inodes_per_block;
 532                 offset = ((ino - 1) % inodes_per_block) *
 533                         EXT2_INODE_SIZE(fs->super);
 534                 io = fs->image_io;
 535         } else {
 536                 group = (ino - 1) / EXT2_INODES_PER_GROUP(fs->super);
 537                 offset = ((ino - 1) % EXT2_INODES_PER_GROUP(fs->super)) *
 538                         EXT2_INODE_SIZE(fs->super);
 539                 block = offset >> EXT2_BLOCK_SIZE_BITS(fs->super);
 540                 if (!fs->group_desc[(unsigned)group].bg_inode_table)
 541                         return EXT2_ET_MISSING_INODE_TABLE;
 542                 block_nr = fs->group_desc[(unsigned)group].bg_inode_table +
 543                         block;
 544                 io = fs->io;
 545         }
 546         offset &= (EXT2_BLOCK_SIZE(fs->super) - 1);
 547
 548         length = EXT2_INODE_SIZE(fs->super);
 549         if (bufsize < length)
 550                 length = bufsize;
 551
 552         ptr = (char *) inode;
 553         while (length) {
 554                 clen = length;
 555                 if ((offset + length) > fs->blocksize)
 556                         clen = fs->blocksize - offset;
 557
 558                 if (block_nr != fs->icache->buffer_blk) {
 559                         retval = io_channel_read_blk(io, block_nr, 1,
 560                                                      fs->icache->buffer);
 561                         if (retval)
 562                                 return retval;
 563                         fs->icache->buffer_blk = block_nr;
 564                 }
 565
 566                 memcpy(ptr, ((char *) fs->icache->buffer) + (unsigned) offset,
 567                        clen);
 568
 569                 offset = 0;
 570                 length -= clen;
 571                 ptr += clen;
 572                 block_nr++;
 573         }
 574
 575 #if BB_BIG_ENDIAN
 576         if ((fs->flags & EXT2_FLAG_SWAP_BYTES) ||
 577             (fs->flags & EXT2_FLAG_SWAP_BYTES_READ))
 578                 ext2fs_swap_inode_full(fs, (struct ext2_inode_large *) inode,
 579                                        (struct ext2_inode_large *) inode,
 580                                        0, length);
 581 #endif
 582
 583         /* Update the inode cache */
 584         fs->icache->cache_last = (fs->icache->cache_last + 1) %
 585                 fs->icache->cache_size;
 586         fs->icache->cache[fs->icache->cache_last].ino = ino;
 587         fs->icache->cache[fs->icache->cache_last].inode = *inode;
 588
 589         return 0;
 590 }
 591
 592 errcode_t ext2fs_read_inode(ext2_filsys fs, ext2_ino_t ino,
 593                             struct ext2_inode * inode)
 594 {
 595         return ext2fs_read_inode_full(fs, ino, inode,
 596                                         sizeof(struct ext2_inode));
 597 }
 598
 599 errcode_t ext2fs_write_inode_full(ext2_filsys fs, ext2_ino_t ino,
 600                                   struct ext2_inode * inode, int bufsize)
 601 {
 602         unsigned long group, block, block_nr, offset;
 603         errcode_t retval = 0;
 604         struct ext2_inode_large temp_inode, *w_inode;
 605         char *ptr;
 606         int clen, i, length;
 607
 608         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 609
 610         /* Check to see if user provided an override function */
 611         if (fs->write_inode) {
 612                 retval = (fs->write_inode)(fs, ino, inode);
 613                 if (retval != EXT2_ET_CALLBACK_NOTHANDLED)
 614                         return retval;
 615         }
 616
 617         /* Check to see if the inode cache needs to be updated */
 618         if (fs->icache) {
 619                 for (i=0; i < fs->icache->cache_size; i++) {
 620                         if (fs->icache->cache[i].ino == ino) {
 621                                 fs->icache->cache[i].inode = *inode;
 622                                 break;
 623                         }
 624                 }
 625         } else {
 626                 retval = create_icache(fs);
 627                 if (retval)
 628                         return retval;
 629         }
 630
 631         if (!(fs->flags & EXT2_FLAG_RW))
 632                 return EXT2_ET_RO_FILSYS;
 633
 634         if ((ino == 0) || (ino > fs->super->s_inodes_count))
 635                 return EXT2_ET_BAD_INODE_NUM;
 636
 637         length = bufsize;
 638         if (length < EXT2_INODE_SIZE(fs->super))
 639                 length = EXT2_INODE_SIZE(fs->super);
 640
 641         if (length > (int) sizeof(struct ext2_inode_large)) {
 642                 w_inode = xmalloc(length);
 643         } else
 644                 w_inode = &temp_inode;
 645         memset(w_inode, 0, length);
 646
 647 #if BB_BIG_ENDIAN
 648         if ((fs->flags & EXT2_FLAG_SWAP_BYTES) ||
 649             (fs->flags & EXT2_FLAG_SWAP_BYTES_WRITE))
 650                 ext2fs_swap_inode_full(fs, w_inode,
 651                                        (struct ext2_inode_large *) inode,
 652                                        1, bufsize);
 653         else
 654 #endif
 655                 memcpy(w_inode, inode, bufsize);
 656
 657         group = (ino - 1) / EXT2_INODES_PER_GROUP(fs->super);
 658         offset = ((ino - 1) % EXT2_INODES_PER_GROUP(fs->super)) *
 659                 EXT2_INODE_SIZE(fs->super);
 660         block = offset >> EXT2_BLOCK_SIZE_BITS(fs->super);
 661         if (!fs->group_desc[(unsigned) group].bg_inode_table)
 662                 return EXT2_ET_MISSING_INODE_TABLE;
 663         block_nr = fs->group_desc[(unsigned) group].bg_inode_table + block;
 664
 665         offset &= (EXT2_BLOCK_SIZE(fs->super) - 1);
 666
 667         length = EXT2_INODE_SIZE(fs->super);
 668         if (length > bufsize)
 669                 length = bufsize;
 670
 671         ptr = (char *) w_inode;
 672
 673         while (length) {
 674                 clen = length;
 675                 if ((offset + length) > fs->blocksize)
 676                         clen = fs->blocksize - offset;
 677
 678                 if (fs->icache->buffer_blk != block_nr) {
 679                         retval = io_channel_read_blk(fs->io, block_nr, 1,
 680                                                      fs->icache->buffer);
 681                         if (retval)
 682                                 goto errout;
 683                         fs->icache->buffer_blk = block_nr;
 684                 }
 685
 686
 687                 memcpy((char *) fs->icache->buffer + (unsigned) offset,
 688                        ptr, clen);
 689
 690                 retval = io_channel_write_blk(fs->io, block_nr, 1,
 691                                               fs->icache->buffer);
 692                 if (retval)
 693                         goto errout;
 694
 695                 offset = 0;
 696                 ptr += clen;
 697                 length -= clen;
 698                 block_nr++;
 699         }
 700
 701         fs->flags |= EXT2_FLAG_CHANGED;
 702 errout:
 703         if (w_inode && w_inode != &temp_inode)
 704                 free(w_inode);
 705         return retval;
 706 }
 707
 708 errcode_t ext2fs_write_inode(ext2_filsys fs, ext2_ino_t ino,
 709                              struct ext2_inode *inode)
 710 {
 711         return ext2fs_write_inode_full(fs, ino, inode,
 712                                        sizeof(struct ext2_inode));
 713 }
 714
 715 /*
 716  * This function should be called when writing a new inode.  It makes
 717  * sure that extra part of large inodes is initialized properly.
 718  */
 719 errcode_t ext2fs_write_new_inode(ext2_filsys fs, ext2_ino_t ino,
 720                                  struct ext2_inode *inode)
 721 {
 722         struct ext2_inode       *buf;
 723         int                     size = EXT2_INODE_SIZE(fs->super);
 724         struct ext2_inode_large *large_inode;
 725
 726         if (size == sizeof(struct ext2_inode))
 727                 return ext2fs_write_inode_full(fs, ino, inode,
 728                                                sizeof(struct ext2_inode));
 729
 730         buf = xmalloc(size);
 731
 732         memset(buf, 0, size);
 733         *buf = *inode;
 734
 735         large_inode = (struct ext2_inode_large *) buf;
 736         large_inode->i_extra_isize = sizeof(struct ext2_inode_large) -
 737                 EXT2_GOOD_OLD_INODE_SIZE;
 738
 739         return ext2fs_write_inode_full(fs, ino, buf, size);
 740 }
 741
 742
 743 errcode_t ext2fs_get_blocks(ext2_filsys fs, ext2_ino_t ino, blk_t *blocks)
 744 {
 745         struct ext2_inode       inode;
 746         int                     i;
 747         errcode_t               retval;
 748
 749         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 750
 751         if (ino > fs->super->s_inodes_count)
 752                 return EXT2_ET_BAD_INODE_NUM;
 753
 754         if (fs->get_blocks) {
 755                 if (!(*fs->get_blocks)(fs, ino, blocks))
 756                         return 0;
 757         }
 758         retval = ext2fs_read_inode(fs, ino, &inode);
 759         if (retval)
 760                 return retval;
 761         for (i=0; i < EXT2_N_BLOCKS; i++)
 762                 blocks[i] = inode.i_block[i];
 763         return 0;
 764 }
 765
 766 errcode_t ext2fs_check_directory(ext2_filsys fs, ext2_ino_t ino)
 767 {
 768         struct  ext2_inode      inode;
 769         errcode_t               retval;
 770
 771         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 772
 773         if (ino > fs->super->s_inodes_count)
 774                 return EXT2_ET_BAD_INODE_NUM;
 775
 776         if (fs->check_directory) {
 777                 retval = (fs->check_directory)(fs, ino);
 778                 if (retval != EXT2_ET_CALLBACK_NOTHANDLED)
 779                         return retval;
 780         }
 781         retval = ext2fs_read_inode(fs, ino, &inode);
 782         if (retval)
 783                 return retval;
 784         if (!LINUX_S_ISDIR(inode.i_mode))
 785                 return EXT2_ET_NO_DIRECTORY;
 786         return 0;
 787 }
 788