lib/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                                               ext2_inode_scan scan,
  48                                               dgrp_t group,
  49                                               void * priv_data);
  50         void *                  done_group_data;
  51         int                     bad_block_ptr;
  52         int                     scan_flags;
  53         int                     reserved[6];
  54 };
  55
  56 /*
  57  * This routine flushes the icache, if it exists.
  58  */
  59 errcode_t ext2fs_flush_icache(ext2_filsys fs)
  60 {
  61         int     i;
  62
  63         if (!fs->icache)
  64                 return 0;
  65
  66         for (i=0; i < fs->icache->cache_size; i++)
  67                 fs->icache->cache[i].ino = 0;
  68
  69         fs->icache->buffer_blk = 0;
  70         return 0;
  71 }
  72
  73 static errcode_t create_icache(ext2_filsys fs)
  74 {
  75         errcode_t       retval;
  76
  77         if (fs->icache)
  78                 return 0;
  79         retval = ext2fs_get_mem(sizeof(struct ext2_inode_cache), &fs->icache);
  80         if (retval)
  81                 return retval;
  82
  83         memset(fs->icache, 0, sizeof(struct ext2_inode_cache));
  84         retval = ext2fs_get_mem(fs->blocksize, &fs->icache->buffer);
  85         if (retval) {
  86                 ext2fs_free_mem(&fs->icache);
  87                 return retval;
  88         }
  89         fs->icache->buffer_blk = 0;
  90         fs->icache->cache_last = -1;
  91         fs->icache->cache_size = 4;
  92         fs->icache->refcount = 1;
  93         retval = ext2fs_get_array(fs->icache->cache_size,
  94                                   sizeof(struct ext2_inode_cache_ent),
  95                                   &fs->icache->cache);
  96         if (retval) {
  97                 ext2fs_free_mem(&fs->icache->buffer);
  98                 ext2fs_free_mem(&fs->icache);
  99                 return retval;
 100         }
 101         ext2fs_flush_icache(fs);
 102         return 0;
 103 }
 104
 105 errcode_t ext2fs_open_inode_scan(ext2_filsys fs, int buffer_blocks,
 106                                  ext2_inode_scan *ret_scan)
 107 {
 108         ext2_inode_scan scan;
 109         errcode_t       retval;
 110         errcode_t (*save_get_blocks)(ext2_filsys f, ext2_ino_t ino, blk_t *blocks);
 111
 112         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 113
 114         /*
 115          * If fs->badblocks isn't set, then set it --- since the inode
 116          * scanning functions require it.
 117          */
 118         if (fs->badblocks == 0) {
 119                 /*
 120                  * Temporarly save fs->get_blocks and set it to zero,
 121                  * for compatibility with old e2fsck's.
 122                  */
 123                 save_get_blocks = fs->get_blocks;
 124                 fs->get_blocks = 0;
 125                 retval = ext2fs_read_bb_inode(fs, &fs->badblocks);
 126                 if (retval && fs->badblocks) {
 127                         ext2fs_badblocks_list_free(fs->badblocks);
 128                         fs->badblocks = 0;
 129                 }
 130                 fs->get_blocks = save_get_blocks;
 131         }
 132
 133         retval = ext2fs_get_mem(sizeof(struct ext2_struct_inode_scan), &scan);
 134         if (retval)
 135                 return retval;
 136         memset(scan, 0, sizeof(struct ext2_struct_inode_scan));
 137
 138         scan->magic = EXT2_ET_MAGIC_INODE_SCAN;
 139         scan->fs = fs;
 140         scan->inode_size = EXT2_INODE_SIZE(fs->super);
 141         scan->bytes_left = 0;
 142         scan->current_group = 0;
 143         scan->groups_left = fs->group_desc_count - 1;
 144         scan->inode_buffer_blocks = buffer_blocks ? buffer_blocks : 8;
 145         scan->current_block = scan->fs->
 146                 group_desc[scan->current_group].bg_inode_table;
 147         scan->inodes_left = EXT2_INODES_PER_GROUP(scan->fs->super);
 148         scan->blocks_left = scan->fs->inode_blocks_per_group;
 149         retval = ext2fs_get_array(scan->inode_buffer_blocks,
 150                                           fs->blocksize,
 151                                 &scan->inode_buffer);
 152         scan->done_group = 0;
 153         scan->done_group_data = 0;
 154         scan->bad_block_ptr = 0;
 155         if (retval) {
 156                 ext2fs_free_mem(&scan);
 157                 return retval;
 158         }
 159         retval = ext2fs_get_mem(scan->inode_size, &scan->temp_buffer);
 160         if (retval) {
 161                 ext2fs_free_mem(&scan->inode_buffer);
 162                 ext2fs_free_mem(&scan);
 163                 return retval;
 164         }
 165         if (scan->fs->badblocks && scan->fs->badblocks->num)
 166                 scan->scan_flags |= EXT2_SF_CHK_BADBLOCKS;
 167         if (EXT2_HAS_COMPAT_FEATURE(fs->super,
 168                                     EXT2_FEATURE_COMPAT_LAZY_BG))
 169                 scan->scan_flags |= EXT2_SF_DO_LAZY;
 170         if (EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
 171                                        EXT4_FEATURE_RO_COMPAT_GDT_CSUM))
 172                 scan->scan_flags |= EXT2_SF_DO_LAZY;
 173         *ret_scan = scan;
 174         return 0;
 175 }
 176
 177 void ext2fs_close_inode_scan(ext2_inode_scan scan)
 178 {
 179         if (!scan || (scan->magic != EXT2_ET_MAGIC_INODE_SCAN))
 180                 return;
 181
 182         ext2fs_free_mem(&scan->inode_buffer);
 183         scan->inode_buffer = NULL;
 184         ext2fs_free_mem(&scan->temp_buffer);
 185         scan->temp_buffer = NULL;
 186         ext2fs_free_mem(&scan);
 187         return;
 188 }
 189
 190 void ext2fs_set_inode_callback(ext2_inode_scan scan,
 191                                errcode_t (*done_group)(ext2_filsys fs,
 192                                                        ext2_inode_scan scan,
 193                                                        dgrp_t group,
 194                                                        void * priv_data),
 195                                void *done_group_data)
 196 {
 197         if (!scan || (scan->magic != EXT2_ET_MAGIC_INODE_SCAN))
 198                 return;
 199
 200         scan->done_group = done_group;
 201         scan->done_group_data = done_group_data;
 202 }
 203
 204 int ext2fs_inode_scan_flags(ext2_inode_scan scan, int set_flags,
 205                             int clear_flags)
 206 {
 207         int     old_flags;
 208
 209         if (!scan || (scan->magic != EXT2_ET_MAGIC_INODE_SCAN))
 210                 return 0;
 211
 212         old_flags = scan->scan_flags;
 213         scan->scan_flags &= ~clear_flags;
 214         scan->scan_flags |= set_flags;
 215         return old_flags;
 216 }
 217
 218 /*
 219  * This function is called by ext2fs_get_next_inode when it needs to
 220  * get ready to read in a new blockgroup.
 221  */
 222 static errcode_t get_next_blockgroup(ext2_inode_scan scan)
 223 {
 224         ext2_filsys fs = scan->fs;
 225
 226         scan->current_group++;
 227         scan->groups_left--;
 228
 229         scan->current_block =fs->group_desc[scan->current_group].bg_inode_table;
 230
 231         scan->current_inode = scan->current_group *
 232                 EXT2_INODES_PER_GROUP(fs->super);
 233
 234         scan->bytes_left = 0;
 235         scan->inodes_left = EXT2_INODES_PER_GROUP(fs->super);
 236         scan->blocks_left = fs->inode_blocks_per_group;
 237         if (EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
 238                                        EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) {
 239                 scan->inodes_left -=
 240                         fs->group_desc[scan->current_group].bg_itable_unused;
 241                 scan->blocks_left =
 242                         (scan->inodes_left +
 243                          (fs->blocksize / scan->inode_size - 1)) *
 244                         scan->inode_size / fs->blocksize;
 245         }
 246
 247         return 0;
 248 }
 249
 250 errcode_t ext2fs_inode_scan_goto_blockgroup(ext2_inode_scan scan,
 251                                             int group)
 252 {
 253         scan->current_group = group - 1;
 254         scan->groups_left = scan->fs->group_desc_count - group;
 255         return get_next_blockgroup(scan);
 256 }
 257
 258 /*
 259  * This function is called by get_next_blocks() to check for bad
 260  * blocks in the inode table.
 261  *
 262  * This function assumes that badblocks_list->list is sorted in
 263  * increasing order.
 264  */
 265 static errcode_t check_for_inode_bad_blocks(ext2_inode_scan scan,
 266                                             blk_t *num_blocks)
 267 {
 268         blk_t   blk = scan->current_block;
 269         badblocks_list  bb = scan->fs->badblocks;
 270
 271         /*
 272          * If the inode table is missing, then obviously there are no
 273          * bad blocks.  :-)
 274          */
 275         if (blk == 0)
 276                 return 0;
 277
 278         /*
 279          * If the current block is greater than the bad block listed
 280          * in the bad block list, then advance the pointer until this
 281          * is no longer the case.  If we run out of bad blocks, then
 282          * we don't need to do any more checking!
 283          */
 284         while (blk > bb->list[scan->bad_block_ptr]) {
 285                 if (++scan->bad_block_ptr >= bb->num) {
 286                         scan->scan_flags &= ~EXT2_SF_CHK_BADBLOCKS;
 287                         return 0;
 288                 }
 289         }
 290
 291         /*
 292          * If the current block is equal to the bad block listed in
 293          * the bad block list, then handle that one block specially.
 294          * (We could try to handle runs of bad blocks, but that
 295          * only increases CPU efficiency by a small amount, at the
 296          * expense of a huge expense of code complexity, and for an
 297          * uncommon case at that.)
 298          */
 299         if (blk == bb->list[scan->bad_block_ptr]) {
 300                 scan->scan_flags |= EXT2_SF_BAD_INODE_BLK;
 301                 *num_blocks = 1;
 302                 if (++scan->bad_block_ptr >= bb->num)
 303                         scan->scan_flags &= ~EXT2_SF_CHK_BADBLOCKS;
 304                 return 0;
 305         }
 306
 307         /*
 308          * If there is a bad block in the range that we're about to
 309          * read in, adjust the number of blocks to read so that we we
 310          * don't read in the bad block.  (Then the next block to read
 311          * will be the bad block, which is handled in the above case.)
 312          */
 313         if ((blk + *num_blocks) > bb->list[scan->bad_block_ptr])
 314                 *num_blocks = (int) (bb->list[scan->bad_block_ptr] - blk);
 315
 316         return 0;
 317 }
 318
 319 /*
 320  * This function is called by ext2fs_get_next_inode when it needs to
 321  * read in more blocks from the current blockgroup's inode table.
 322  */
 323 static errcode_t get_next_blocks(ext2_inode_scan scan)
 324 {
 325         blk_t           num_blocks;
 326         errcode_t       retval;
 327
 328         /*
 329          * Figure out how many blocks to read; we read at most
 330          * inode_buffer_blocks, and perhaps less if there aren't that
 331          * many blocks left to read.
 332          */
 333         num_blocks = scan->inode_buffer_blocks;
 334         if (num_blocks > scan->blocks_left)
 335                 num_blocks = scan->blocks_left;
 336
 337         /*
 338          * If the past block "read" was a bad block, then mark the
 339          * left-over extra bytes as also being bad.
 340          */
 341         if (scan->scan_flags & EXT2_SF_BAD_INODE_BLK) {
 342                 if (scan->bytes_left)
 343                         scan->scan_flags |= EXT2_SF_BAD_EXTRA_BYTES;
 344                 scan->scan_flags &= ~EXT2_SF_BAD_INODE_BLK;
 345         }
 346
 347         /*
 348          * Do inode bad block processing, if necessary.
 349          */
 350         if (scan->scan_flags & EXT2_SF_CHK_BADBLOCKS) {
 351                 retval = check_for_inode_bad_blocks(scan, &num_blocks);
 352                 if (retval)
 353                         return retval;
 354         }
 355
 356         if ((scan->scan_flags & EXT2_SF_BAD_INODE_BLK) ||
 357             (scan->current_block == 0)) {
 358                 memset(scan->inode_buffer, 0,
 359                        (size_t) num_blocks * scan->fs->blocksize);
 360         } else {
 361                 retval = io_channel_read_blk(scan->fs->io,
 362                                              scan->current_block,
 363                                              (int) num_blocks,
 364                                              scan->inode_buffer);
 365                 if (retval)
 366                         return EXT2_ET_NEXT_INODE_READ;
 367         }
 368         scan->ptr = scan->inode_buffer;
 369         scan->bytes_left = num_blocks * scan->fs->blocksize;
 370
 371         scan->blocks_left -= num_blocks;
 372         if (scan->current_block)
 373                 scan->current_block += num_blocks;
 374         return 0;
 375 }
 376
 377 #if 0
 378 /*
 379  * Returns 1 if the entire inode_buffer has a non-zero size and
 380  * contains all zeros.  (Not just deleted inodes, since that means
 381  * that part of the inode table was used at one point; we want all
 382  * zeros, which means that the inode table is pristine.)
 383  */
 384 static inline int is_empty_scan(ext2_inode_scan scan)
 385 {
 386         int     i;
 387
 388         if (scan->bytes_left == 0)
 389                 return 0;
 390
 391         for (i=0; i < scan->bytes_left; i++)
 392                 if (scan->ptr[i])
 393                         return 0;
 394         return 1;
 395 }
 396 #endif
 397
 398 errcode_t ext2fs_get_next_inode_full(ext2_inode_scan scan, ext2_ino_t *ino,
 399                                      struct ext2_inode *inode, int bufsize)
 400 {
 401         errcode_t       retval;
 402         int             extra_bytes = 0;
 403
 404         EXT2_CHECK_MAGIC(scan, EXT2_ET_MAGIC_INODE_SCAN);
 405
 406         /*
 407          * Do we need to start reading a new block group?
 408          */
 409         if (scan->inodes_left <= 0) {
 410         force_new_group:
 411                 if (scan->done_group) {
 412                         retval = (scan->done_group)
 413                                 (scan->fs, scan, scan->current_group,
 414                                  scan->done_group_data);
 415                         if (retval)
 416                                 return retval;
 417                 }
 418                 if (scan->groups_left <= 0) {
 419                         *ino = 0;
 420                         return 0;
 421                 }
 422                 retval = get_next_blockgroup(scan);
 423                 if (retval)
 424                         return retval;
 425         }
 426         /*
 427          * These checks are done outside the above if statement so
 428          * they can be done for block group #0.
 429          */
 430         if ((scan->scan_flags & EXT2_SF_DO_LAZY) &&
 431             (scan->fs->group_desc[scan->current_group].bg_flags &
 432              EXT2_BG_INODE_UNINIT))
 433                 goto force_new_group;
 434         if (scan->inodes_left == 0)
 435                 goto force_new_group;
 436         if (scan->current_block == 0) {
 437                 if (scan->scan_flags & EXT2_SF_SKIP_MISSING_ITABLE) {
 438                         goto force_new_group;
 439                 } else
 440                         return EXT2_ET_MISSING_INODE_TABLE;
 441         }
 442
 443
 444         /*
 445          * Have we run out of space in the inode buffer?  If so, we
 446          * need to read in more blocks.
 447          */
 448         if (scan->bytes_left < scan->inode_size) {
 449                 memcpy(scan->temp_buffer, scan->ptr, scan->bytes_left);
 450                 extra_bytes = scan->bytes_left;
 451
 452                 retval = get_next_blocks(scan);
 453                 if (retval)
 454                         return retval;
 455 #if 0
 456                 /*
 457                  * XXX test  Need check for used inode somehow.
 458                  * (Note: this is hard.)
 459                  */
 460                 if (is_empty_scan(scan))
 461                         goto force_new_group;
 462 #endif
 463         }
 464
 465         retval = 0;
 466         if (extra_bytes) {
 467                 memcpy(scan->temp_buffer+extra_bytes, scan->ptr,
 468                        scan->inode_size - extra_bytes);
 469                 scan->ptr += scan->inode_size - extra_bytes;
 470                 scan->bytes_left -= scan->inode_size - extra_bytes;
 471
 472 #ifdef WORDS_BIGENDIAN
 473                 memset(inode, 0, bufsize);
 474                 ext2fs_swap_inode_full(scan->fs,
 475                                (struct ext2_inode_large *) inode,
 476                                (struct ext2_inode_large *) scan->temp_buffer,
 477                                0, bufsize);
 478 #else
 479                 *inode = *((struct ext2_inode *) scan->temp_buffer);
 480 #endif
 481                 if (scan->scan_flags & EXT2_SF_BAD_EXTRA_BYTES)
 482                         retval = EXT2_ET_BAD_BLOCK_IN_INODE_TABLE;
 483                 scan->scan_flags &= ~EXT2_SF_BAD_EXTRA_BYTES;
 484         } else {
 485 #ifdef WORDS_BIGENDIAN
 486                 memset(inode, 0, bufsize);
 487                 ext2fs_swap_inode_full(scan->fs,
 488                                 (struct ext2_inode_large *) inode,
 489                                 (struct ext2_inode_large *) scan->ptr,
 490                                 0, bufsize);
 491 #else
 492                 memcpy(inode, scan->ptr, bufsize);
 493 #endif
 494                 scan->ptr += scan->inode_size;
 495                 scan->bytes_left -= scan->inode_size;
 496                 if (scan->scan_flags & EXT2_SF_BAD_INODE_BLK)
 497                         retval = EXT2_ET_BAD_BLOCK_IN_INODE_TABLE;
 498         }
 499
 500         scan->inodes_left--;
 501         scan->current_inode++;
 502         *ino = scan->current_inode;
 503         return retval;
 504 }
 505
 506 errcode_t ext2fs_get_next_inode(ext2_inode_scan scan, ext2_ino_t *ino,
 507                                 struct ext2_inode *inode)
 508 {
 509         return ext2fs_get_next_inode_full(scan, ino, inode,
 510                                                 sizeof(struct ext2_inode));
 511 }
 512
 513 /*
 514  * Functions to read and write a single inode.
 515  */
 516 errcode_t ext2fs_read_inode_full(ext2_filsys fs, ext2_ino_t ino,
 517                                  struct ext2_inode * inode, int bufsize)
 518 {
 519         unsigned long   group, block, block_nr, offset;
 520         char            *ptr;
 521         errcode_t       retval;
 522         int             clen, i, inodes_per_block, length;
 523         io_channel      io;
 524
 525         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 526
 527         /* Check to see if user has an override function */
 528         if (fs->read_inode) {
 529                 retval = (fs->read_inode)(fs, ino, inode);
 530                 if (retval != EXT2_ET_CALLBACK_NOTHANDLED)
 531                         return retval;
 532         }
 533         /* Create inode cache if not present */
 534         if (!fs->icache) {
 535                 retval = create_icache(fs);
 536                 if (retval)
 537                         return retval;
 538         }
 539         /* Check to see if it's in the inode cache */
 540         if (bufsize == sizeof(struct ext2_inode)) {
 541                 /* only old good inode can be retrieve from the cache */
 542                 for (i=0; i < fs->icache->cache_size; i++) {
 543                         if (fs->icache->cache[i].ino == ino) {
 544                                 *inode = fs->icache->cache[i].inode;
 545                                 return 0;
 546                         }
 547                 }
 548         }
 549         if ((ino == 0) || (ino > fs->super->s_inodes_count))
 550                 return EXT2_ET_BAD_INODE_NUM;
 551         if (fs->flags & EXT2_FLAG_IMAGE_FILE) {
 552                 inodes_per_block = fs->blocksize / EXT2_INODE_SIZE(fs->super);
 553                 block_nr = fs->image_header->offset_inode / fs->blocksize;
 554                 block_nr += (ino - 1) / inodes_per_block;
 555                 offset = ((ino - 1) % inodes_per_block) *
 556                         EXT2_INODE_SIZE(fs->super);
 557                 io = fs->image_io;
 558         } else {
 559                 group = (ino - 1) / EXT2_INODES_PER_GROUP(fs->super);
 560                 offset = ((ino - 1) % EXT2_INODES_PER_GROUP(fs->super)) *
 561                         EXT2_INODE_SIZE(fs->super);
 562                 block = offset >> EXT2_BLOCK_SIZE_BITS(fs->super);
 563                 if (!fs->group_desc[(unsigned)group].bg_inode_table)
 564                         return EXT2_ET_MISSING_INODE_TABLE;
 565                 block_nr = fs->group_desc[(unsigned)group].bg_inode_table +
 566                         block;
 567                 io = fs->io;
 568         }
 569         offset &= (EXT2_BLOCK_SIZE(fs->super) - 1);
 570
 571         length = EXT2_INODE_SIZE(fs->super);
 572         if (bufsize < length)
 573                 length = bufsize;
 574
 575         ptr = (char *) inode;
 576         while (length) {
 577                 clen = length;
 578                 if ((offset + length) > fs->blocksize)
 579                         clen = fs->blocksize - offset;
 580
 581                 if (block_nr != fs->icache->buffer_blk) {
 582                         retval = io_channel_read_blk(io, block_nr, 1,
 583                                                      fs->icache->buffer);
 584                         if (retval)
 585                                 return retval;
 586                         fs->icache->buffer_blk = block_nr;
 587                 }
 588
 589                 memcpy(ptr, ((char *) fs->icache->buffer) + (unsigned) offset,
 590                        clen);
 591
 592                 offset = 0;
 593                 length -= clen;
 594                 ptr += clen;
 595                 block_nr++;
 596         }
 597
 598 #ifdef WORDS_BIGENDIAN
 599         ext2fs_swap_inode_full(fs, (struct ext2_inode_large *) inode,
 600                                (struct ext2_inode_large *) inode,
 601                                0, bufsize);
 602 #endif
 603
 604         /* Update the inode cache */
 605         fs->icache->cache_last = (fs->icache->cache_last + 1) %
 606                 fs->icache->cache_size;
 607         fs->icache->cache[fs->icache->cache_last].ino = ino;
 608         fs->icache->cache[fs->icache->cache_last].inode = *inode;
 609
 610         return 0;
 611 }
 612
 613 errcode_t ext2fs_read_inode(ext2_filsys fs, ext2_ino_t ino,
 614                             struct ext2_inode * inode)
 615 {
 616         return ext2fs_read_inode_full(fs, ino, inode,
 617                                         sizeof(struct ext2_inode));
 618 }
 619
 620 errcode_t ext2fs_write_inode_full(ext2_filsys fs, ext2_ino_t ino,
 621                                   struct ext2_inode * inode, int bufsize)
 622 {
 623         unsigned long group, block, block_nr, offset;
 624         errcode_t retval = 0;
 625         struct ext2_inode_large temp_inode, *w_inode;
 626         char *ptr;
 627         int clen, i, length;
 628
 629         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 630
 631         /* Check to see if user provided an override function */
 632         if (fs->write_inode) {
 633                 retval = (fs->write_inode)(fs, ino, inode);
 634                 if (retval != EXT2_ET_CALLBACK_NOTHANDLED)
 635                         return retval;
 636         }
 637
 638         /* Check to see if the inode cache needs to be updated */
 639         if (fs->icache) {
 640                 for (i=0; i < fs->icache->cache_size; i++) {
 641                         if (fs->icache->cache[i].ino == ino) {
 642                                 fs->icache->cache[i].inode = *inode;
 643                                 break;
 644                         }
 645                 }
 646         } else {
 647                 retval = create_icache(fs);
 648                 if (retval)
 649                         return retval;
 650         }
 651
 652         if (!(fs->flags & EXT2_FLAG_RW))
 653                 return EXT2_ET_RO_FILSYS;
 654
 655         if ((ino == 0) || (ino > fs->super->s_inodes_count))
 656                 return EXT2_ET_BAD_INODE_NUM;
 657
 658         length = bufsize;
 659         if (length < EXT2_INODE_SIZE(fs->super))
 660                 length = EXT2_INODE_SIZE(fs->super);
 661
 662         if (length > (int) sizeof(struct ext2_inode_large)) {
 663                 w_inode = malloc(length);
 664                 if (!w_inode)
 665                         return ENOMEM;
 666         } else
 667                 w_inode = &temp_inode;
 668         memset(w_inode, 0, length);
 669
 670 #ifdef WORDS_BIGENDIAN
 671         ext2fs_swap_inode_full(fs, w_inode,
 672                                (struct ext2_inode_large *) inode,
 673                                1, bufsize);
 674 #else
 675         memcpy(w_inode, inode, bufsize);
 676 #endif
 677
 678         group = (ino - 1) / EXT2_INODES_PER_GROUP(fs->super);
 679         offset = ((ino - 1) % EXT2_INODES_PER_GROUP(fs->super)) *
 680                 EXT2_INODE_SIZE(fs->super);
 681         block = offset >> EXT2_BLOCK_SIZE_BITS(fs->super);
 682         if (!fs->group_desc[(unsigned) group].bg_inode_table) {
 683                 retval = EXT2_ET_MISSING_INODE_TABLE;
 684                 goto errout;
 685         }
 686         block_nr = fs->group_desc[(unsigned) group].bg_inode_table + block;
 687
 688         offset &= (EXT2_BLOCK_SIZE(fs->super) - 1);
 689
 690         length = EXT2_INODE_SIZE(fs->super);
 691         if (length > bufsize)
 692                 length = bufsize;
 693
 694         ptr = (char *) w_inode;
 695
 696         while (length) {
 697                 clen = length;
 698                 if ((offset + length) > fs->blocksize)
 699                         clen = fs->blocksize - offset;
 700
 701                 if (fs->icache->buffer_blk != block_nr) {
 702                         retval = io_channel_read_blk(fs->io, block_nr, 1,
 703                                                      fs->icache->buffer);
 704                         if (retval)
 705                                 goto errout;
 706                         fs->icache->buffer_blk = block_nr;
 707                 }
 708
 709
 710                 memcpy((char *) fs->icache->buffer + (unsigned) offset,
 711                        ptr, clen);
 712
 713                 retval = io_channel_write_blk(fs->io, block_nr, 1,
 714                                               fs->icache->buffer);
 715                 if (retval)
 716                         goto errout;
 717
 718                 offset = 0;
 719                 ptr += clen;
 720                 length -= clen;
 721                 block_nr++;
 722         }
 723
 724         fs->flags |= EXT2_FLAG_CHANGED;
 725 errout:
 726         if (w_inode && w_inode != &temp_inode)
 727                 free(w_inode);
 728         return retval;
 729 }
 730
 731 errcode_t ext2fs_write_inode(ext2_filsys fs, ext2_ino_t ino,
 732                              struct ext2_inode *inode)
 733 {
 734         return ext2fs_write_inode_full(fs, ino, inode,
 735                                        sizeof(struct ext2_inode));
 736 }
 737
 738 /*
 739  * This function should be called when writing a new inode.  It makes
 740  * sure that extra part of large inodes is initialized properly.
 741  */
 742 errcode_t ext2fs_write_new_inode(ext2_filsys fs, ext2_ino_t ino,
 743                                  struct ext2_inode *inode)
 744 {
 745         struct ext2_inode       *buf;
 746         int                     size = EXT2_INODE_SIZE(fs->super);
 747         struct ext2_inode_large *large_inode;
 748         errcode_t               retval;
 749
 750         if (size == sizeof(struct ext2_inode))
 751                 return ext2fs_write_inode_full(fs, ino, inode,
 752                                                sizeof(struct ext2_inode));
 753
 754         buf = malloc(size);
 755         if (!buf)
 756                 return ENOMEM;
 757
 758         memset(buf, 0, size);
 759         *buf = *inode;
 760
 761         large_inode = (struct ext2_inode_large *) buf;
 762         large_inode->i_extra_isize = sizeof(struct ext2_inode_large) -
 763                 EXT2_GOOD_OLD_INODE_SIZE;
 764
 765         retval = ext2fs_write_inode_full(fs, ino, buf, size);
 766         free(buf);
 767         return retval;
 768 }
 769
 770
 771 errcode_t ext2fs_get_blocks(ext2_filsys fs, ext2_ino_t ino, blk_t *blocks)
 772 {
 773         struct ext2_inode       inode;
 774         int                     i;
 775         errcode_t               retval;
 776
 777         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 778
 779         if (ino > fs->super->s_inodes_count)
 780                 return EXT2_ET_BAD_INODE_NUM;
 781
 782         if (fs->get_blocks) {
 783                 if (!(*fs->get_blocks)(fs, ino, blocks))
 784                         return 0;
 785         }
 786         retval = ext2fs_read_inode(fs, ino, &inode);
 787         if (retval)
 788                 return retval;
 789         for (i=0; i < EXT2_N_BLOCKS; i++)
 790                 blocks[i] = inode.i_block[i];
 791         return 0;
 792 }
 793
 794 errcode_t ext2fs_check_directory(ext2_filsys fs, ext2_ino_t ino)
 795 {
 796         struct  ext2_inode      inode;
 797         errcode_t               retval;
 798
 799         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 800
 801         if (ino > fs->super->s_inodes_count)
 802                 return EXT2_ET_BAD_INODE_NUM;
 803
 804         if (fs->check_directory) {
 805                 retval = (fs->check_directory)(fs, ino);
 806                 if (retval != EXT2_ET_CALLBACK_NOTHANDLED)
 807                         return retval;
 808         }
 809         retval = ext2fs_read_inode(fs, ino, &inode);
 810         if (retval)
 811                 return retval;
 812         if (!LINUX_S_ISDIR(inode.i_mode))
 813                 return EXT2_ET_NO_DIRECTORY;
 814         return 0;
 815 }
 816