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 #include <time.h>
  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 struct ext2_struct_inode_scan {
  33         errcode_t               magic;
  34         ext2_filsys             fs;
  35         ext2_ino_t              current_inode;
  36         blk_t                   current_block;
  37         dgrp_t                  current_group;
  38         ext2_ino_t              inodes_left;
  39         blk_t                   blocks_left;
  40         dgrp_t                  groups_left;
  41         blk_t                   inode_buffer_blocks;
  42         char *                  inode_buffer;
  43         int                     inode_size;
  44         char *                  ptr;
  45         int                     bytes_left;
  46         char                    *temp_buffer;
  47         errcode_t               (*done_group)(ext2_filsys fs,
  48                                               ext2_inode_scan scan,
  49                                               dgrp_t group,
  50                                               void * priv_data);
  51         void *                  done_group_data;
  52         int                     bad_block_ptr;
  53         int                     scan_flags;
  54         int                     reserved[6];
  55 };
  56
  57 /*
  58  * This routine flushes the icache, if it exists.
  59  */
  60 errcode_t ext2fs_flush_icache(ext2_filsys fs)
  61 {
  62         int     i;
  63
  64         if (!fs->icache)
  65                 return 0;
  66
  67         for (i=0; i < fs->icache->cache_size; i++)
  68                 fs->icache->cache[i].ino = 0;
  69
  70         fs->icache->buffer_blk = 0;
  71         return 0;
  72 }
  73
  74 static errcode_t create_icache(ext2_filsys fs)
  75 {
  76         errcode_t       retval;
  77
  78         if (fs->icache)
  79                 return 0;
  80         retval = ext2fs_get_mem(sizeof(struct ext2_inode_cache), &fs->icache);
  81         if (retval)
  82                 return retval;
  83
  84         memset(fs->icache, 0, sizeof(struct ext2_inode_cache));
  85         retval = ext2fs_get_mem(fs->blocksize, &fs->icache->buffer);
  86         if (retval) {
  87                 ext2fs_free_mem(&fs->icache);
  88                 return retval;
  89         }
  90         fs->icache->buffer_blk = 0;
  91         fs->icache->cache_last = -1;
  92         fs->icache->cache_size = 4;
  93         fs->icache->refcount = 1;
  94         retval = ext2fs_get_array(fs->icache->cache_size,
  95                                   sizeof(struct ext2_inode_cache_ent),
  96                                   &fs->icache->cache);
  97         if (retval) {
  98                 ext2fs_free_mem(&fs->icache->buffer);
  99                 ext2fs_free_mem(&fs->icache);
 100                 return retval;
 101         }
 102         ext2fs_flush_icache(fs);
 103         return 0;
 104 }
 105
 106 errcode_t ext2fs_open_inode_scan(ext2_filsys fs, int buffer_blocks,
 107                                  ext2_inode_scan *ret_scan)
 108 {
 109         ext2_inode_scan scan;
 110         errcode_t       retval;
 111         errcode_t (*save_get_blocks)(ext2_filsys f, ext2_ino_t ino, blk_t *blocks);
 112
 113         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 114
 115         /*
 116          * If fs->badblocks isn't set, then set it --- since the inode
 117          * scanning functions require it.
 118          */
 119         if (fs->badblocks == 0) {
 120                 /*
 121                  * Temporarly save fs->get_blocks and set it to zero,
 122                  * for compatibility with old e2fsck's.
 123                  */
 124                 save_get_blocks = fs->get_blocks;
 125                 fs->get_blocks = 0;
 126                 retval = ext2fs_read_bb_inode(fs, &fs->badblocks);
 127                 if (retval && fs->badblocks) {
 128                         ext2fs_badblocks_list_free(fs->badblocks);
 129                         fs->badblocks = 0;
 130                 }
 131                 fs->get_blocks = save_get_blocks;
 132         }
 133
 134         retval = ext2fs_get_mem(sizeof(struct ext2_struct_inode_scan), &scan);
 135         if (retval)
 136                 return retval;
 137         memset(scan, 0, sizeof(struct ext2_struct_inode_scan));
 138
 139         scan->magic = EXT2_ET_MAGIC_INODE_SCAN;
 140         scan->fs = fs;
 141         scan->inode_size = EXT2_INODE_SIZE(fs->super);
 142         scan->bytes_left = 0;
 143         scan->current_group = 0;
 144         scan->groups_left = fs->group_desc_count - 1;
 145         scan->inode_buffer_blocks = buffer_blocks ? buffer_blocks : 8;
 146         scan->current_block = scan->fs->
 147                 group_desc[scan->current_group].bg_inode_table;
 148         scan->inodes_left = EXT2_INODES_PER_GROUP(scan->fs->super);
 149         scan->blocks_left = scan->fs->inode_blocks_per_group;
 150         if (EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
 151                                        EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) {
 152                 scan->inodes_left -=
 153                         fs->group_desc[scan->current_group].bg_itable_unused;
 154                 scan->blocks_left =
 155                         (scan->inodes_left +
 156                          (fs->blocksize / scan->inode_size - 1)) *
 157                         scan->inode_size / fs->blocksize;
 158         }
 159         retval = ext2fs_get_array(scan->inode_buffer_blocks,
 160                                           fs->blocksize,
 161                                 &scan->inode_buffer);
 162         scan->done_group = 0;
 163         scan->done_group_data = 0;
 164         scan->bad_block_ptr = 0;
 165         if (retval) {
 166                 ext2fs_free_mem(&scan);
 167                 return retval;
 168         }
 169         retval = ext2fs_get_mem(scan->inode_size, &scan->temp_buffer);
 170         if (retval) {
 171                 ext2fs_free_mem(&scan->inode_buffer);
 172                 ext2fs_free_mem(&scan);
 173                 return retval;
 174         }
 175         if (scan->fs->badblocks && scan->fs->badblocks->num)
 176                 scan->scan_flags |= EXT2_SF_CHK_BADBLOCKS;
 177         if (EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
 178                                        EXT4_FEATURE_RO_COMPAT_GDT_CSUM))
 179                 scan->scan_flags |= EXT2_SF_DO_LAZY;
 180         *ret_scan = scan;
 181         return 0;
 182 }
 183
 184 void ext2fs_close_inode_scan(ext2_inode_scan scan)
 185 {
 186         if (!scan || (scan->magic != EXT2_ET_MAGIC_INODE_SCAN))
 187                 return;
 188
 189         ext2fs_free_mem(&scan->inode_buffer);
 190         scan->inode_buffer = NULL;
 191         ext2fs_free_mem(&scan->temp_buffer);
 192         scan->temp_buffer = NULL;
 193         ext2fs_free_mem(&scan);
 194         return;
 195 }
 196
 197 void ext2fs_set_inode_callback(ext2_inode_scan scan,
 198                                errcode_t (*done_group)(ext2_filsys fs,
 199                                                        ext2_inode_scan scan,
 200                                                        dgrp_t group,
 201                                                        void * priv_data),
 202                                void *done_group_data)
 203 {
 204         if (!scan || (scan->magic != EXT2_ET_MAGIC_INODE_SCAN))
 205                 return;
 206
 207         scan->done_group = done_group;
 208         scan->done_group_data = done_group_data;
 209 }
 210
 211 int ext2fs_inode_scan_flags(ext2_inode_scan scan, int set_flags,
 212                             int clear_flags)
 213 {
 214         int     old_flags;
 215
 216         if (!scan || (scan->magic != EXT2_ET_MAGIC_INODE_SCAN))
 217                 return 0;
 218
 219         old_flags = scan->scan_flags;
 220         scan->scan_flags &= ~clear_flags;
 221         scan->scan_flags |= set_flags;
 222         return old_flags;
 223 }
 224
 225 /*
 226  * This function is called by ext2fs_get_next_inode when it needs to
 227  * get ready to read in a new blockgroup.
 228  */
 229 static errcode_t get_next_blockgroup(ext2_inode_scan scan)
 230 {
 231         ext2_filsys fs = scan->fs;
 232
 233         scan->current_group++;
 234         scan->groups_left--;
 235
 236         scan->current_block =fs->group_desc[scan->current_group].bg_inode_table;
 237
 238         scan->current_inode = scan->current_group *
 239                 EXT2_INODES_PER_GROUP(fs->super);
 240
 241         scan->bytes_left = 0;
 242         scan->inodes_left = EXT2_INODES_PER_GROUP(fs->super);
 243         scan->blocks_left = fs->inode_blocks_per_group;
 244         if (EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
 245                                        EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) {
 246                 scan->inodes_left -=
 247                         fs->group_desc[scan->current_group].bg_itable_unused;
 248                 scan->blocks_left =
 249                         (scan->inodes_left +
 250                          (fs->blocksize / scan->inode_size - 1)) *
 251                         scan->inode_size / fs->blocksize;
 252         }
 253
 254         return 0;
 255 }
 256
 257 errcode_t ext2fs_inode_scan_goto_blockgroup(ext2_inode_scan scan,
 258                                             int group)
 259 {
 260         scan->current_group = group - 1;
 261         scan->groups_left = scan->fs->group_desc_count - group;
 262         return get_next_blockgroup(scan);
 263 }
 264
 265 /*
 266  * This function is called by get_next_blocks() to check for bad
 267  * blocks in the inode table.
 268  *
 269  * This function assumes that badblocks_list->list is sorted in
 270  * increasing order.
 271  */
 272 static errcode_t check_for_inode_bad_blocks(ext2_inode_scan scan,
 273                                             blk_t *num_blocks)
 274 {
 275         blk_t   blk = scan->current_block;
 276         badblocks_list  bb = scan->fs->badblocks;
 277
 278         /*
 279          * If the inode table is missing, then obviously there are no
 280          * bad blocks.  :-)
 281          */
 282         if (blk == 0)
 283                 return 0;
 284
 285         /*
 286          * If the current block is greater than the bad block listed
 287          * in the bad block list, then advance the pointer until this
 288          * is no longer the case.  If we run out of bad blocks, then
 289          * we don't need to do any more checking!
 290          */
 291         while (blk > bb->list[scan->bad_block_ptr]) {
 292                 if (++scan->bad_block_ptr >= bb->num) {
 293                         scan->scan_flags &= ~EXT2_SF_CHK_BADBLOCKS;
 294                         return 0;
 295                 }
 296         }
 297
 298         /*
 299          * If the current block is equal to the bad block listed in
 300          * the bad block list, then handle that one block specially.
 301          * (We could try to handle runs of bad blocks, but that
 302          * only increases CPU efficiency by a small amount, at the
 303          * expense of a huge expense of code complexity, and for an
 304          * uncommon case at that.)
 305          */
 306         if (blk == bb->list[scan->bad_block_ptr]) {
 307                 scan->scan_flags |= EXT2_SF_BAD_INODE_BLK;
 308                 *num_blocks = 1;
 309                 if (++scan->bad_block_ptr >= bb->num)
 310                         scan->scan_flags &= ~EXT2_SF_CHK_BADBLOCKS;
 311                 return 0;
 312         }
 313
 314         /*
 315          * If there is a bad block in the range that we're about to
 316          * read in, adjust the number of blocks to read so that we we
 317          * don't read in the bad block.  (Then the next block to read
 318          * will be the bad block, which is handled in the above case.)
 319          */
 320         if ((blk + *num_blocks) > bb->list[scan->bad_block_ptr])
 321                 *num_blocks = (int) (bb->list[scan->bad_block_ptr] - blk);
 322
 323         return 0;
 324 }
 325
 326 /*
 327  * This function is called by ext2fs_get_next_inode when it needs to
 328  * read in more blocks from the current blockgroup's inode table.
 329  */
 330 static errcode_t get_next_blocks(ext2_inode_scan scan)
 331 {
 332         blk_t           num_blocks;
 333         errcode_t       retval;
 334
 335         /*
 336          * Figure out how many blocks to read; we read at most
 337          * inode_buffer_blocks, and perhaps less if there aren't that
 338          * many blocks left to read.
 339          */
 340         num_blocks = scan->inode_buffer_blocks;
 341         if (num_blocks > scan->blocks_left)
 342                 num_blocks = scan->blocks_left;
 343
 344         /*
 345          * If the past block "read" was a bad block, then mark the
 346          * left-over extra bytes as also being bad.
 347          */
 348         if (scan->scan_flags & EXT2_SF_BAD_INODE_BLK) {
 349                 if (scan->bytes_left)
 350                         scan->scan_flags |= EXT2_SF_BAD_EXTRA_BYTES;
 351                 scan->scan_flags &= ~EXT2_SF_BAD_INODE_BLK;
 352         }
 353
 354         /*
 355          * Do inode bad block processing, if necessary.
 356          */
 357         if (scan->scan_flags & EXT2_SF_CHK_BADBLOCKS) {
 358                 retval = check_for_inode_bad_blocks(scan, &num_blocks);
 359                 if (retval)
 360                         return retval;
 361         }
 362
 363         if ((scan->scan_flags & EXT2_SF_BAD_INODE_BLK) ||
 364             (scan->current_block == 0)) {
 365                 memset(scan->inode_buffer, 0,
 366                        (size_t) num_blocks * scan->fs->blocksize);
 367         } else {
 368                 retval = io_channel_read_blk(scan->fs->io,
 369                                              scan->current_block,
 370                                              (int) num_blocks,
 371                                              scan->inode_buffer);
 372                 if (retval)
 373                         return EXT2_ET_NEXT_INODE_READ;
 374         }
 375         scan->ptr = scan->inode_buffer;
 376         scan->bytes_left = num_blocks * scan->fs->blocksize;
 377
 378         scan->blocks_left -= num_blocks;
 379         if (scan->current_block)
 380                 scan->current_block += num_blocks;
 381         return 0;
 382 }
 383
 384 #if 0
 385 /*
 386  * Returns 1 if the entire inode_buffer has a non-zero size and
 387  * contains all zeros.  (Not just deleted inodes, since that means
 388  * that part of the inode table was used at one point; we want all
 389  * zeros, which means that the inode table is pristine.)
 390  */
 391 static inline int is_empty_scan(ext2_inode_scan scan)
 392 {
 393         int     i;
 394
 395         if (scan->bytes_left == 0)
 396                 return 0;
 397
 398         for (i=0; i < scan->bytes_left; i++)
 399                 if (scan->ptr[i])
 400                         return 0;
 401         return 1;
 402 }
 403 #endif
 404
 405 errcode_t ext2fs_get_next_inode_full(ext2_inode_scan scan, ext2_ino_t *ino,
 406                                      struct ext2_inode *inode, int bufsize)
 407 {
 408         errcode_t       retval;
 409         int             extra_bytes = 0;
 410
 411         EXT2_CHECK_MAGIC(scan, EXT2_ET_MAGIC_INODE_SCAN);
 412
 413         /*
 414          * Do we need to start reading a new block group?
 415          */
 416         if (scan->inodes_left <= 0) {
 417         force_new_group:
 418                 if (scan->done_group) {
 419                         retval = (scan->done_group)
 420                                 (scan->fs, scan, scan->current_group,
 421                                  scan->done_group_data);
 422                         if (retval)
 423                                 return retval;
 424                 }
 425                 if (scan->groups_left <= 0) {
 426                         *ino = 0;
 427                         return 0;
 428                 }
 429                 retval = get_next_blockgroup(scan);
 430                 if (retval)
 431                         return retval;
 432         }
 433         /*
 434          * These checks are done outside the above if statement so
 435          * they can be done for block group #0.
 436          */
 437         if ((scan->scan_flags & EXT2_SF_DO_LAZY) &&
 438             (scan->fs->group_desc[scan->current_group].bg_flags &
 439              EXT2_BG_INODE_UNINIT))
 440                 goto force_new_group;
 441         if (scan->inodes_left == 0)
 442                 goto force_new_group;
 443         if (scan->current_block == 0) {
 444                 if (scan->scan_flags & EXT2_SF_SKIP_MISSING_ITABLE) {
 445                         goto force_new_group;
 446                 } else
 447                         return EXT2_ET_MISSING_INODE_TABLE;
 448         }
 449
 450
 451         /*
 452          * Have we run out of space in the inode buffer?  If so, we
 453          * need to read in more blocks.
 454          */
 455         if (scan->bytes_left < scan->inode_size) {
 456                 memcpy(scan->temp_buffer, scan->ptr, scan->bytes_left);
 457                 extra_bytes = scan->bytes_left;
 458
 459                 retval = get_next_blocks(scan);
 460                 if (retval)
 461                         return retval;
 462 #if 0
 463                 /*
 464                  * XXX test  Need check for used inode somehow.
 465                  * (Note: this is hard.)
 466                  */
 467                 if (is_empty_scan(scan))
 468                         goto force_new_group;
 469 #endif
 470         }
 471
 472         retval = 0;
 473         if (extra_bytes) {
 474                 memcpy(scan->temp_buffer+extra_bytes, scan->ptr,
 475                        scan->inode_size - extra_bytes);
 476                 scan->ptr += scan->inode_size - extra_bytes;
 477                 scan->bytes_left -= scan->inode_size - extra_bytes;
 478
 479 #ifdef WORDS_BIGENDIAN
 480                 memset(inode, 0, bufsize);
 481                 ext2fs_swap_inode_full(scan->fs,
 482                                (struct ext2_inode_large *) inode,
 483                                (struct ext2_inode_large *) scan->temp_buffer,
 484                                0, bufsize);
 485 #else
 486                 *inode = *((struct ext2_inode *) scan->temp_buffer);
 487 #endif
 488                 if (scan->scan_flags & EXT2_SF_BAD_EXTRA_BYTES)
 489                         retval = EXT2_ET_BAD_BLOCK_IN_INODE_TABLE;
 490                 scan->scan_flags &= ~EXT2_SF_BAD_EXTRA_BYTES;
 491         } else {
 492 #ifdef WORDS_BIGENDIAN
 493                 memset(inode, 0, bufsize);
 494                 ext2fs_swap_inode_full(scan->fs,
 495                                 (struct ext2_inode_large *) inode,
 496                                 (struct ext2_inode_large *) scan->ptr,
 497                                 0, bufsize);
 498 #else
 499                 memcpy(inode, scan->ptr, bufsize);
 500 #endif
 501                 scan->ptr += scan->inode_size;
 502                 scan->bytes_left -= scan->inode_size;
 503                 if (scan->scan_flags & EXT2_SF_BAD_INODE_BLK)
 504                         retval = EXT2_ET_BAD_BLOCK_IN_INODE_TABLE;
 505         }
 506
 507         scan->inodes_left--;
 508         scan->current_inode++;
 509         *ino = scan->current_inode;
 510         return retval;
 511 }
 512
 513 errcode_t ext2fs_get_next_inode(ext2_inode_scan scan, ext2_ino_t *ino,
 514                                 struct ext2_inode *inode)
 515 {
 516         return ext2fs_get_next_inode_full(scan, ino, inode,
 517                                                 sizeof(struct ext2_inode));
 518 }
 519
 520 /*
 521  * Functions to read and write a single inode.
 522  */
 523 errcode_t ext2fs_read_inode_full(ext2_filsys fs, ext2_ino_t ino,
 524                                  struct ext2_inode * inode, int bufsize)
 525 {
 526         unsigned long   group, block, block_nr, offset;
 527         char            *ptr;
 528         errcode_t       retval;
 529         int             clen, i, inodes_per_block, length;
 530         io_channel      io;
 531
 532         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 533
 534         /* Check to see if user has an override function */
 535         if (fs->read_inode) {
 536                 retval = (fs->read_inode)(fs, ino, inode);
 537                 if (retval != EXT2_ET_CALLBACK_NOTHANDLED)
 538                         return retval;
 539         }
 540         if ((ino == 0) || (ino > fs->super->s_inodes_count))
 541                 return EXT2_ET_BAD_INODE_NUM;
 542         /* Create inode cache if not present */
 543         if (!fs->icache) {
 544                 retval = create_icache(fs);
 545                 if (retval)
 546                         return retval;
 547         }
 548         /* Check to see if it's in the inode cache */
 549         if (bufsize == sizeof(struct ext2_inode)) {
 550                 /* only old good inode can be retrieved from the cache */
 551                 for (i=0; i < fs->icache->cache_size; i++) {
 552                         if (fs->icache->cache[i].ino == ino) {
 553                                 *inode = fs->icache->cache[i].inode;
 554                                 return 0;
 555                         }
 556                 }
 557         }
 558         if (fs->flags & EXT2_FLAG_IMAGE_FILE) {
 559                 inodes_per_block = fs->blocksize / EXT2_INODE_SIZE(fs->super);
 560                 block_nr = fs->image_header->offset_inode / fs->blocksize;
 561                 block_nr += (ino - 1) / inodes_per_block;
 562                 offset = ((ino - 1) % inodes_per_block) *
 563                         EXT2_INODE_SIZE(fs->super);
 564                 io = fs->image_io;
 565         } else {
 566                 group = (ino - 1) / EXT2_INODES_PER_GROUP(fs->super);
 567                 if (group > fs->group_desc_count)
 568                         return EXT2_ET_BAD_INODE_NUM;
 569                 offset = ((ino - 1) % EXT2_INODES_PER_GROUP(fs->super)) *
 570                         EXT2_INODE_SIZE(fs->super);
 571                 block = offset >> EXT2_BLOCK_SIZE_BITS(fs->super);
 572                 if (!fs->group_desc[(unsigned)group].bg_inode_table)
 573                         return EXT2_ET_MISSING_INODE_TABLE;
 574                 block_nr = fs->group_desc[(unsigned)group].bg_inode_table +
 575                         block;
 576                 io = fs->io;
 577         }
 578         offset &= (EXT2_BLOCK_SIZE(fs->super) - 1);
 579
 580         length = EXT2_INODE_SIZE(fs->super);
 581         if (bufsize < length)
 582                 length = bufsize;
 583
 584         ptr = (char *) inode;
 585         while (length) {
 586                 clen = length;
 587                 if ((offset + length) > fs->blocksize)
 588                         clen = fs->blocksize - offset;
 589
 590                 if (block_nr != fs->icache->buffer_blk) {
 591                         retval = io_channel_read_blk(io, block_nr, 1,
 592                                                      fs->icache->buffer);
 593                         if (retval)
 594                                 return retval;
 595                         fs->icache->buffer_blk = block_nr;
 596                 }
 597
 598                 memcpy(ptr, ((char *) fs->icache->buffer) + (unsigned) offset,
 599                        clen);
 600
 601                 offset = 0;
 602                 length -= clen;
 603                 ptr += clen;
 604                 block_nr++;
 605         }
 606
 607 #ifdef WORDS_BIGENDIAN
 608         ext2fs_swap_inode_full(fs, (struct ext2_inode_large *) inode,
 609                                (struct ext2_inode_large *) inode,
 610                                0, bufsize);
 611 #endif
 612
 613         /* Update the inode cache */
 614         fs->icache->cache_last = (fs->icache->cache_last + 1) %
 615                 fs->icache->cache_size;
 616         fs->icache->cache[fs->icache->cache_last].ino = ino;
 617         fs->icache->cache[fs->icache->cache_last].inode = *inode;
 618
 619         return 0;
 620 }
 621
 622 errcode_t ext2fs_read_inode(ext2_filsys fs, ext2_ino_t ino,
 623                             struct ext2_inode * inode)
 624 {
 625         return ext2fs_read_inode_full(fs, ino, inode,
 626                                         sizeof(struct ext2_inode));
 627 }
 628
 629 errcode_t ext2fs_write_inode_full(ext2_filsys fs, ext2_ino_t ino,
 630                                   struct ext2_inode * inode, int bufsize)
 631 {
 632         unsigned long group, block, block_nr, offset;
 633         errcode_t retval = 0;
 634         struct ext2_inode_large temp_inode, *w_inode;
 635         char *ptr;
 636         int clen, i, length;
 637
 638         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 639
 640         /* Check to see if user provided an override function */
 641         if (fs->write_inode) {
 642                 retval = (fs->write_inode)(fs, ino, inode);
 643                 if (retval != EXT2_ET_CALLBACK_NOTHANDLED)
 644                         return retval;
 645         }
 646
 647         /* Check to see if the inode cache needs to be updated */
 648         if (fs->icache) {
 649                 for (i=0; i < fs->icache->cache_size; i++) {
 650                         if (fs->icache->cache[i].ino == ino) {
 651                                 fs->icache->cache[i].inode = *inode;
 652                                 break;
 653                         }
 654                 }
 655         } else {
 656                 retval = create_icache(fs);
 657                 if (retval)
 658                         return retval;
 659         }
 660
 661         if (!(fs->flags & EXT2_FLAG_RW))
 662                 return EXT2_ET_RO_FILSYS;
 663
 664         if ((ino == 0) || (ino > fs->super->s_inodes_count))
 665                 return EXT2_ET_BAD_INODE_NUM;
 666
 667         length = bufsize;
 668         if (length < EXT2_INODE_SIZE(fs->super))
 669                 length = EXT2_INODE_SIZE(fs->super);
 670
 671         if (length > (int) sizeof(struct ext2_inode_large)) {
 672                 w_inode = malloc(length);
 673                 if (!w_inode)
 674                         return ENOMEM;
 675         } else
 676                 w_inode = &temp_inode;
 677         memset(w_inode, 0, length);
 678
 679 #ifdef WORDS_BIGENDIAN
 680         ext2fs_swap_inode_full(fs, w_inode,
 681                                (struct ext2_inode_large *) inode,
 682                                1, bufsize);
 683 #else
 684         memcpy(w_inode, inode, bufsize);
 685 #endif
 686
 687         group = (ino - 1) / EXT2_INODES_PER_GROUP(fs->super);
 688         offset = ((ino - 1) % EXT2_INODES_PER_GROUP(fs->super)) *
 689                 EXT2_INODE_SIZE(fs->super);
 690         block = offset >> EXT2_BLOCK_SIZE_BITS(fs->super);
 691         if (!fs->group_desc[(unsigned) group].bg_inode_table) {
 692                 retval = EXT2_ET_MISSING_INODE_TABLE;
 693                 goto errout;
 694         }
 695         block_nr = fs->group_desc[(unsigned) group].bg_inode_table + block;
 696
 697         offset &= (EXT2_BLOCK_SIZE(fs->super) - 1);
 698
 699         length = EXT2_INODE_SIZE(fs->super);
 700         if (length > bufsize)
 701                 length = bufsize;
 702
 703         ptr = (char *) w_inode;
 704
 705         while (length) {
 706                 clen = length;
 707                 if ((offset + length) > fs->blocksize)
 708                         clen = fs->blocksize - offset;
 709
 710                 if (fs->icache->buffer_blk != block_nr) {
 711                         retval = io_channel_read_blk(fs->io, block_nr, 1,
 712                                                      fs->icache->buffer);
 713                         if (retval)
 714                                 goto errout;
 715                         fs->icache->buffer_blk = block_nr;
 716                 }
 717
 718
 719                 memcpy((char *) fs->icache->buffer + (unsigned) offset,
 720                        ptr, clen);
 721
 722                 retval = io_channel_write_blk(fs->io, block_nr, 1,
 723                                               fs->icache->buffer);
 724                 if (retval)
 725                         goto errout;
 726
 727                 offset = 0;
 728                 ptr += clen;
 729                 length -= clen;
 730                 block_nr++;
 731         }
 732
 733         fs->flags |= EXT2_FLAG_CHANGED;
 734 errout:
 735         if (w_inode && w_inode != &temp_inode)
 736                 free(w_inode);
 737         return retval;
 738 }
 739
 740 errcode_t ext2fs_write_inode(ext2_filsys fs, ext2_ino_t ino,
 741                              struct ext2_inode *inode)
 742 {
 743         return ext2fs_write_inode_full(fs, ino, inode,
 744                                        sizeof(struct ext2_inode));
 745 }
 746
 747 /*
 748  * This function should be called when writing a new inode.  It makes
 749  * sure that extra part of large inodes is initialized properly.
 750  */
 751 errcode_t ext2fs_write_new_inode(ext2_filsys fs, ext2_ino_t ino,
 752                                  struct ext2_inode *inode)
 753 {
 754         struct ext2_inode       *buf;
 755         int                     size = EXT2_INODE_SIZE(fs->super);
 756         struct ext2_inode_large *large_inode;
 757         errcode_t               retval;
 758         __u32                   t = fs->now ? fs->now : time(NULL);
 759
 760         if (!inode->i_ctime)
 761                 inode->i_ctime = t;
 762         if (!inode->i_mtime)
 763                 inode->i_mtime = t;
 764         if (!inode->i_atime)
 765                 inode->i_atime = t;
 766
 767         if (size == sizeof(struct ext2_inode))
 768                 return ext2fs_write_inode_full(fs, ino, inode,
 769                                                sizeof(struct ext2_inode));
 770
 771         buf = malloc(size);
 772         if (!buf)
 773                 return ENOMEM;
 774
 775         memset(buf, 0, size);
 776         *buf = *inode;
 777
 778         large_inode = (struct ext2_inode_large *) buf;
 779         large_inode->i_extra_isize = sizeof(struct ext2_inode_large) -
 780                 EXT2_GOOD_OLD_INODE_SIZE;
 781         if (!large_inode->i_crtime)
 782                 large_inode->i_crtime = t;
 783
 784         retval = ext2fs_write_inode_full(fs, ino, buf, size);
 785         free(buf);
 786         return retval;
 787 }
 788
 789
 790 errcode_t ext2fs_get_blocks(ext2_filsys fs, ext2_ino_t ino, blk_t *blocks)
 791 {
 792         struct ext2_inode       inode;
 793         int                     i;
 794         errcode_t               retval;
 795
 796         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 797
 798         if (ino > fs->super->s_inodes_count)
 799                 return EXT2_ET_BAD_INODE_NUM;
 800
 801         if (fs->get_blocks) {
 802                 if (!(*fs->get_blocks)(fs, ino, blocks))
 803                         return 0;
 804         }
 805         retval = ext2fs_read_inode(fs, ino, &inode);
 806         if (retval)
 807                 return retval;
 808         for (i=0; i < EXT2_N_BLOCKS; i++)
 809                 blocks[i] = inode.i_block[i];
 810         return 0;
 811 }
 812
 813 errcode_t ext2fs_check_directory(ext2_filsys fs, ext2_ino_t ino)
 814 {
 815         struct  ext2_inode      inode;
 816         errcode_t               retval;
 817
 818         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 819
 820         if (ino > fs->super->s_inodes_count)
 821                 return EXT2_ET_BAD_INODE_NUM;
 822
 823         if (fs->check_directory) {
 824                 retval = (fs->check_directory)(fs, ino);
 825                 if (retval != EXT2_ET_CALLBACK_NOTHANDLED)
 826                         return retval;
 827         }
 828         retval = ext2fs_read_inode(fs, ino, &inode);
 829         if (retval)
 830                 return retval;
 831         if (!LINUX_S_ISDIR(inode.i_mode))
 832                 return EXT2_ET_NO_DIRECTORY;
 833         return 0;
 834 }
 835