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 Library
   8  * General Public License, version 2.
   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_memalign(scan->inode_buffer_blocks * fs->blocksize,
 160                                      fs->blocksize, &scan->inode_buffer);
 161         scan->done_group = 0;
 162         scan->done_group_data = 0;
 163         scan->bad_block_ptr = 0;
 164         if (retval) {
 165                 ext2fs_free_mem(&scan);
 166                 return retval;
 167         }
 168         retval = ext2fs_get_mem(scan->inode_size, &scan->temp_buffer);
 169         if (retval) {
 170                 ext2fs_free_mem(&scan->inode_buffer);
 171                 ext2fs_free_mem(&scan);
 172                 return retval;
 173         }
 174         if (scan->fs->badblocks && scan->fs->badblocks->num)
 175                 scan->scan_flags |= EXT2_SF_CHK_BADBLOCKS;
 176         if (EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
 177                                        EXT4_FEATURE_RO_COMPAT_GDT_CSUM))
 178                 scan->scan_flags |= EXT2_SF_DO_LAZY;
 179         *ret_scan = scan;
 180         return 0;
 181 }
 182
 183 void ext2fs_close_inode_scan(ext2_inode_scan scan)
 184 {
 185         if (!scan || (scan->magic != EXT2_ET_MAGIC_INODE_SCAN))
 186                 return;
 187
 188         ext2fs_free_mem(&scan->inode_buffer);
 189         scan->inode_buffer = NULL;
 190         ext2fs_free_mem(&scan->temp_buffer);
 191         scan->temp_buffer = NULL;
 192         ext2fs_free_mem(&scan);
 193         return;
 194 }
 195
 196 void ext2fs_set_inode_callback(ext2_inode_scan scan,
 197                                errcode_t (*done_group)(ext2_filsys fs,
 198                                                        ext2_inode_scan scan,
 199                                                        dgrp_t group,
 200                                                        void * priv_data),
 201                                void *done_group_data)
 202 {
 203         if (!scan || (scan->magic != EXT2_ET_MAGIC_INODE_SCAN))
 204                 return;
 205
 206         scan->done_group = done_group;
 207         scan->done_group_data = done_group_data;
 208 }
 209
 210 int ext2fs_inode_scan_flags(ext2_inode_scan scan, int set_flags,
 211                             int clear_flags)
 212 {
 213         int     old_flags;
 214
 215         if (!scan || (scan->magic != EXT2_ET_MAGIC_INODE_SCAN))
 216                 return 0;
 217
 218         old_flags = scan->scan_flags;
 219         scan->scan_flags &= ~clear_flags;
 220         scan->scan_flags |= set_flags;
 221         return old_flags;
 222 }
 223
 224 /*
 225  * This function is called by ext2fs_get_next_inode when it needs to
 226  * get ready to read in a new blockgroup.
 227  */
 228 static errcode_t get_next_blockgroup(ext2_inode_scan scan)
 229 {
 230         ext2_filsys fs = scan->fs;
 231
 232         scan->current_group++;
 233         scan->groups_left--;
 234
 235         scan->current_block =fs->group_desc[scan->current_group].bg_inode_table;
 236
 237         scan->current_inode = scan->current_group *
 238                 EXT2_INODES_PER_GROUP(fs->super);
 239
 240         scan->bytes_left = 0;
 241         scan->inodes_left = EXT2_INODES_PER_GROUP(fs->super);
 242         scan->blocks_left = fs->inode_blocks_per_group;
 243         if (EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
 244                                        EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) {
 245                 scan->inodes_left -=
 246                         fs->group_desc[scan->current_group].bg_itable_unused;
 247                 scan->blocks_left =
 248                         (scan->inodes_left +
 249                          (fs->blocksize / scan->inode_size - 1)) *
 250                         scan->inode_size / fs->blocksize;
 251         }
 252
 253         return 0;
 254 }
 255
 256 errcode_t ext2fs_inode_scan_goto_blockgroup(ext2_inode_scan scan,
 257                                             int group)
 258 {
 259         scan->current_group = group - 1;
 260         scan->groups_left = scan->fs->group_desc_count - group;
 261         return get_next_blockgroup(scan);
 262 }
 263
 264 /*
 265  * This function is called by get_next_blocks() to check for bad
 266  * blocks in the inode table.
 267  *
 268  * This function assumes that badblocks_list->list is sorted in
 269  * increasing order.
 270  */
 271 static errcode_t check_for_inode_bad_blocks(ext2_inode_scan scan,
 272                                             blk_t *num_blocks)
 273 {
 274         blk_t   blk = scan->current_block;
 275         badblocks_list  bb = scan->fs->badblocks;
 276
 277         /*
 278          * If the inode table is missing, then obviously there are no
 279          * bad blocks.  :-)
 280          */
 281         if (blk == 0)
 282                 return 0;
 283
 284         /*
 285          * If the current block is greater than the bad block listed
 286          * in the bad block list, then advance the pointer until this
 287          * is no longer the case.  If we run out of bad blocks, then
 288          * we don't need to do any more checking!
 289          */
 290         while (blk > bb->list[scan->bad_block_ptr]) {
 291                 if (++scan->bad_block_ptr >= bb->num) {
 292                         scan->scan_flags &= ~EXT2_SF_CHK_BADBLOCKS;
 293                         return 0;
 294                 }
 295         }
 296
 297         /*
 298          * If the current block is equal to the bad block listed in
 299          * the bad block list, then handle that one block specially.
 300          * (We could try to handle runs of bad blocks, but that
 301          * only increases CPU efficiency by a small amount, at the
 302          * expense of a huge expense of code complexity, and for an
 303          * uncommon case at that.)
 304          */
 305         if (blk == bb->list[scan->bad_block_ptr]) {
 306                 scan->scan_flags |= EXT2_SF_BAD_INODE_BLK;
 307                 *num_blocks = 1;
 308                 if (++scan->bad_block_ptr >= bb->num)
 309                         scan->scan_flags &= ~EXT2_SF_CHK_BADBLOCKS;
 310                 return 0;
 311         }
 312
 313         /*
 314          * If there is a bad block in the range that we're about to
 315          * read in, adjust the number of blocks to read so that we we
 316          * don't read in the bad block.  (Then the next block to read
 317          * will be the bad block, which is handled in the above case.)
 318          */
 319         if ((blk + *num_blocks) > bb->list[scan->bad_block_ptr])
 320                 *num_blocks = (int) (bb->list[scan->bad_block_ptr] - blk);
 321
 322         return 0;
 323 }
 324
 325 /*
 326  * This function is called by ext2fs_get_next_inode when it needs to
 327  * read in more blocks from the current blockgroup's inode table.
 328  */
 329 static errcode_t get_next_blocks(ext2_inode_scan scan)
 330 {
 331         blk_t           num_blocks;
 332         errcode_t       retval;
 333
 334         /*
 335          * Figure out how many blocks to read; we read at most
 336          * inode_buffer_blocks, and perhaps less if there aren't that
 337          * many blocks left to read.
 338          */
 339         num_blocks = scan->inode_buffer_blocks;
 340         if (num_blocks > scan->blocks_left)
 341                 num_blocks = scan->blocks_left;
 342
 343         /*
 344          * If the past block "read" was a bad block, then mark the
 345          * left-over extra bytes as also being bad.
 346          */
 347         if (scan->scan_flags & EXT2_SF_BAD_INODE_BLK) {
 348                 if (scan->bytes_left)
 349                         scan->scan_flags |= EXT2_SF_BAD_EXTRA_BYTES;
 350                 scan->scan_flags &= ~EXT2_SF_BAD_INODE_BLK;
 351         }
 352
 353         /*
 354          * Do inode bad block processing, if necessary.
 355          */
 356         if (scan->scan_flags & EXT2_SF_CHK_BADBLOCKS) {
 357                 retval = check_for_inode_bad_blocks(scan, &num_blocks);
 358                 if (retval)
 359                         return retval;
 360         }
 361
 362         if ((scan->scan_flags & EXT2_SF_BAD_INODE_BLK) ||
 363             (scan->current_block == 0)) {
 364                 memset(scan->inode_buffer, 0,
 365                        (size_t) num_blocks * scan->fs->blocksize);
 366         } else {
 367                 retval = io_channel_read_blk(scan->fs->io,
 368                                              scan->current_block,
 369                                              (int) num_blocks,
 370                                              scan->inode_buffer);
 371                 if (retval)
 372                         return EXT2_ET_NEXT_INODE_READ;
 373         }
 374         scan->ptr = scan->inode_buffer;
 375         scan->bytes_left = num_blocks * scan->fs->blocksize;
 376
 377         scan->blocks_left -= num_blocks;
 378         if (scan->current_block)
 379                 scan->current_block += num_blocks;
 380         return 0;
 381 }
 382
 383 #if 0
 384 /*
 385  * Returns 1 if the entire inode_buffer has a non-zero size and
 386  * contains all zeros.  (Not just deleted inodes, since that means
 387  * that part of the inode table was used at one point; we want all
 388  * zeros, which means that the inode table is pristine.)
 389  */
 390 static inline int is_empty_scan(ext2_inode_scan scan)
 391 {
 392         int     i;
 393
 394         if (scan->bytes_left == 0)
 395                 return 0;
 396
 397         for (i=0; i < scan->bytes_left; i++)
 398                 if (scan->ptr[i])
 399                         return 0;
 400         return 1;
 401 }
 402 #endif
 403
 404 errcode_t ext2fs_get_next_inode_full(ext2_inode_scan scan, ext2_ino_t *ino,
 405                                      struct ext2_inode *inode, int bufsize)
 406 {
 407         errcode_t       retval;
 408         int             extra_bytes = 0;
 409
 410         EXT2_CHECK_MAGIC(scan, EXT2_ET_MAGIC_INODE_SCAN);
 411
 412         /*
 413          * Do we need to start reading a new block group?
 414          */
 415         if (scan->inodes_left <= 0) {
 416         force_new_group:
 417                 if (scan->done_group) {
 418                         retval = (scan->done_group)
 419                                 (scan->fs, scan, scan->current_group,
 420                                  scan->done_group_data);
 421                         if (retval)
 422                                 return retval;
 423                 }
 424                 if (scan->groups_left <= 0) {
 425                         *ino = 0;
 426                         return 0;
 427                 }
 428                 retval = get_next_blockgroup(scan);
 429                 if (retval)
 430                         return retval;
 431         }
 432         /*
 433          * These checks are done outside the above if statement so
 434          * they can be done for block group #0.
 435          */
 436         if ((scan->scan_flags & EXT2_SF_DO_LAZY) &&
 437             (scan->fs->group_desc[scan->current_group].bg_flags &
 438              EXT2_BG_INODE_UNINIT))
 439                 goto force_new_group;
 440         if (scan->inodes_left == 0)
 441                 goto force_new_group;
 442         if (scan->current_block == 0) {
 443                 if (scan->scan_flags & EXT2_SF_SKIP_MISSING_ITABLE) {
 444                         goto force_new_group;
 445                 } else
 446                         return EXT2_ET_MISSING_INODE_TABLE;
 447         }
 448
 449
 450         /*
 451          * Have we run out of space in the inode buffer?  If so, we
 452          * need to read in more blocks.
 453          */
 454         if (scan->bytes_left < scan->inode_size) {
 455                 memcpy(scan->temp_buffer, scan->ptr, scan->bytes_left);
 456                 extra_bytes = scan->bytes_left;
 457
 458                 retval = get_next_blocks(scan);
 459                 if (retval)
 460                         return retval;
 461 #if 0
 462                 /*
 463                  * XXX test  Need check for used inode somehow.
 464                  * (Note: this is hard.)
 465                  */
 466                 if (is_empty_scan(scan))
 467                         goto force_new_group;
 468 #endif
 469         }
 470
 471         retval = 0;
 472         if (extra_bytes) {
 473                 memcpy(scan->temp_buffer+extra_bytes, scan->ptr,
 474                        scan->inode_size - extra_bytes);
 475                 scan->ptr += scan->inode_size - extra_bytes;
 476                 scan->bytes_left -= scan->inode_size - extra_bytes;
 477
 478 #ifdef WORDS_BIGENDIAN
 479                 memset(inode, 0, bufsize);
 480                 ext2fs_swap_inode_full(scan->fs,
 481                                (struct ext2_inode_large *) inode,
 482                                (struct ext2_inode_large *) scan->temp_buffer,
 483                                0, bufsize);
 484 #else
 485                 *inode = *((struct ext2_inode *) scan->temp_buffer);
 486 #endif
 487                 if (scan->scan_flags & EXT2_SF_BAD_EXTRA_BYTES)
 488                         retval = EXT2_ET_BAD_BLOCK_IN_INODE_TABLE;
 489                 scan->scan_flags &= ~EXT2_SF_BAD_EXTRA_BYTES;
 490         } else {
 491 #ifdef WORDS_BIGENDIAN
 492                 memset(inode, 0, bufsize);
 493                 ext2fs_swap_inode_full(scan->fs,
 494                                 (struct ext2_inode_large *) inode,
 495                                 (struct ext2_inode_large *) scan->ptr,
 496                                 0, bufsize);
 497 #else
 498                 memcpy(inode, scan->ptr, bufsize);
 499 #endif
 500                 scan->ptr += scan->inode_size;
 501                 scan->bytes_left -= scan->inode_size;
 502                 if (scan->scan_flags & EXT2_SF_BAD_INODE_BLK)
 503                         retval = EXT2_ET_BAD_BLOCK_IN_INODE_TABLE;
 504         }
 505
 506         scan->inodes_left--;
 507         scan->current_inode++;
 508         *ino = scan->current_inode;
 509         return retval;
 510 }
 511
 512 errcode_t ext2fs_get_next_inode(ext2_inode_scan scan, ext2_ino_t *ino,
 513                                 struct ext2_inode *inode)
 514 {
 515         return ext2fs_get_next_inode_full(scan, ino, inode,
 516                                                 sizeof(struct ext2_inode));
 517 }
 518
 519 /*
 520  * Functions to read and write a single inode.
 521  */
 522 errcode_t ext2fs_read_inode_full(ext2_filsys fs, ext2_ino_t ino,
 523                                  struct ext2_inode * inode, int bufsize)
 524 {
 525         unsigned long   group, block, block_nr, offset;
 526         char            *ptr;
 527         errcode_t       retval;
 528         int             clen, i, inodes_per_block, length;
 529         io_channel      io;
 530
 531         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 532
 533         /* Check to see if user has an override function */
 534         if (fs->read_inode) {
 535                 retval = (fs->read_inode)(fs, ino, inode);
 536                 if (retval != EXT2_ET_CALLBACK_NOTHANDLED)
 537                         return retval;
 538         }
 539         if ((ino == 0) || (ino > fs->super->s_inodes_count))
 540                 return EXT2_ET_BAD_INODE_NUM;
 541         /* Create inode cache if not present */
 542         if (!fs->icache) {
 543                 retval = create_icache(fs);
 544                 if (retval)
 545                         return retval;
 546         }
 547         /* Check to see if it's in the inode cache */
 548         if (bufsize == sizeof(struct ext2_inode)) {
 549                 /* only old good inode can be retrieved from the cache */
 550                 for (i=0; i < fs->icache->cache_size; i++) {
 551                         if (fs->icache->cache[i].ino == ino) {
 552                                 *inode = fs->icache->cache[i].inode;
 553                                 return 0;
 554                         }
 555                 }
 556         }
 557         if (fs->flags & EXT2_FLAG_IMAGE_FILE) {
 558                 inodes_per_block = fs->blocksize / EXT2_INODE_SIZE(fs->super);
 559                 block_nr = fs->image_header->offset_inode / fs->blocksize;
 560                 block_nr += (ino - 1) / inodes_per_block;
 561                 offset = ((ino - 1) % inodes_per_block) *
 562                         EXT2_INODE_SIZE(fs->super);
 563                 io = fs->image_io;
 564         } else {
 565                 group = (ino - 1) / EXT2_INODES_PER_GROUP(fs->super);
 566                 if (group > fs->group_desc_count)
 567                         return EXT2_ET_BAD_INODE_NUM;
 568                 offset = ((ino - 1) % EXT2_INODES_PER_GROUP(fs->super)) *
 569                         EXT2_INODE_SIZE(fs->super);
 570                 block = offset >> EXT2_BLOCK_SIZE_BITS(fs->super);
 571                 if (!fs->group_desc[(unsigned)group].bg_inode_table)
 572                         return EXT2_ET_MISSING_INODE_TABLE;
 573                 block_nr = fs->group_desc[(unsigned)group].bg_inode_table +
 574                         block;
 575                 io = fs->io;
 576         }
 577         offset &= (EXT2_BLOCK_SIZE(fs->super) - 1);
 578
 579         length = EXT2_INODE_SIZE(fs->super);
 580         if (bufsize < length)
 581                 length = bufsize;
 582
 583         ptr = (char *) inode;
 584         while (length) {
 585                 clen = length;
 586                 if ((offset + length) > fs->blocksize)
 587                         clen = fs->blocksize - offset;
 588
 589                 if (block_nr != fs->icache->buffer_blk) {
 590                         retval = io_channel_read_blk(io, block_nr, 1,
 591                                                      fs->icache->buffer);
 592                         if (retval)
 593                                 return retval;
 594                         fs->icache->buffer_blk = block_nr;
 595                 }
 596
 597                 memcpy(ptr, ((char *) fs->icache->buffer) + (unsigned) offset,
 598                        clen);
 599
 600                 offset = 0;
 601                 length -= clen;
 602                 ptr += clen;
 603                 block_nr++;
 604         }
 605
 606 #ifdef WORDS_BIGENDIAN
 607         ext2fs_swap_inode_full(fs, (struct ext2_inode_large *) inode,
 608                                (struct ext2_inode_large *) inode,
 609                                0, bufsize);
 610 #endif
 611
 612         /* Update the inode cache */
 613         fs->icache->cache_last = (fs->icache->cache_last + 1) %
 614                 fs->icache->cache_size;
 615         fs->icache->cache[fs->icache->cache_last].ino = ino;
 616         fs->icache->cache[fs->icache->cache_last].inode = *inode;
 617
 618         return 0;
 619 }
 620
 621 errcode_t ext2fs_read_inode(ext2_filsys fs, ext2_ino_t ino,
 622                             struct ext2_inode * inode)
 623 {
 624         return ext2fs_read_inode_full(fs, ino, inode,
 625                                         sizeof(struct ext2_inode));
 626 }
 627
 628 errcode_t ext2fs_write_inode_full(ext2_filsys fs, ext2_ino_t ino,
 629                                   struct ext2_inode * inode, int bufsize)
 630 {
 631         unsigned long group, block, block_nr, offset;
 632         errcode_t retval = 0;
 633         struct ext2_inode_large temp_inode, *w_inode;
 634         char *ptr;
 635         int clen, i, length;
 636
 637         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 638
 639         /* Check to see if user provided an override function */
 640         if (fs->write_inode) {
 641                 retval = (fs->write_inode)(fs, ino, inode);
 642                 if (retval != EXT2_ET_CALLBACK_NOTHANDLED)
 643                         return retval;
 644         }
 645
 646         /* Check to see if the inode cache needs to be updated */
 647         if (fs->icache) {
 648                 for (i=0; i < fs->icache->cache_size; i++) {
 649                         if (fs->icache->cache[i].ino == ino) {
 650                                 fs->icache->cache[i].inode = *inode;
 651                                 break;
 652                         }
 653                 }
 654         } else {
 655                 retval = create_icache(fs);
 656                 if (retval)
 657                         return retval;
 658         }
 659
 660         if (!(fs->flags & EXT2_FLAG_RW))
 661                 return EXT2_ET_RO_FILSYS;
 662
 663         if ((ino == 0) || (ino > fs->super->s_inodes_count))
 664                 return EXT2_ET_BAD_INODE_NUM;
 665
 666         length = bufsize;
 667         if (length < EXT2_INODE_SIZE(fs->super))
 668                 length = EXT2_INODE_SIZE(fs->super);
 669
 670         if (length > (int) sizeof(struct ext2_inode_large)) {
 671                 w_inode = malloc(length);
 672                 if (!w_inode)
 673                         return ENOMEM;
 674         } else
 675                 w_inode = &temp_inode;
 676         memset(w_inode, 0, length);
 677
 678 #ifdef WORDS_BIGENDIAN
 679         ext2fs_swap_inode_full(fs, w_inode,
 680                                (struct ext2_inode_large *) inode,
 681                                1, bufsize);
 682 #else
 683         memcpy(w_inode, inode, bufsize);
 684 #endif
 685
 686         group = (ino - 1) / EXT2_INODES_PER_GROUP(fs->super);
 687         offset = ((ino - 1) % EXT2_INODES_PER_GROUP(fs->super)) *
 688                 EXT2_INODE_SIZE(fs->super);
 689         block = offset >> EXT2_BLOCK_SIZE_BITS(fs->super);
 690         if (!fs->group_desc[(unsigned) group].bg_inode_table) {
 691                 retval = EXT2_ET_MISSING_INODE_TABLE;
 692                 goto errout;
 693         }
 694         block_nr = fs->group_desc[(unsigned) group].bg_inode_table + block;
 695
 696         offset &= (EXT2_BLOCK_SIZE(fs->super) - 1);
 697
 698         length = EXT2_INODE_SIZE(fs->super);
 699         if (length > bufsize)
 700                 length = bufsize;
 701
 702         ptr = (char *) w_inode;
 703
 704         while (length) {
 705                 clen = length;
 706                 if ((offset + length) > fs->blocksize)
 707                         clen = fs->blocksize - offset;
 708
 709                 if (fs->icache->buffer_blk != block_nr) {
 710                         retval = io_channel_read_blk(fs->io, block_nr, 1,
 711                                                      fs->icache->buffer);
 712                         if (retval)
 713                                 goto errout;
 714                         fs->icache->buffer_blk = block_nr;
 715                 }
 716
 717
 718                 memcpy((char *) fs->icache->buffer + (unsigned) offset,
 719                        ptr, clen);
 720
 721                 retval = io_channel_write_blk(fs->io, block_nr, 1,
 722                                               fs->icache->buffer);
 723                 if (retval)
 724                         goto errout;
 725
 726                 offset = 0;
 727                 ptr += clen;
 728                 length -= clen;
 729                 block_nr++;
 730         }
 731
 732         fs->flags |= EXT2_FLAG_CHANGED;
 733 errout:
 734         if (w_inode && w_inode != &temp_inode)
 735                 free(w_inode);
 736         return retval;
 737 }
 738
 739 errcode_t ext2fs_write_inode(ext2_filsys fs, ext2_ino_t ino,
 740                              struct ext2_inode *inode)
 741 {
 742         return ext2fs_write_inode_full(fs, ino, inode,
 743                                        sizeof(struct ext2_inode));
 744 }
 745
 746 /*
 747  * This function should be called when writing a new inode.  It makes
 748  * sure that extra part of large inodes is initialized properly.
 749  */
 750 errcode_t ext2fs_write_new_inode(ext2_filsys fs, ext2_ino_t ino,
 751                                  struct ext2_inode *inode)
 752 {
 753         struct ext2_inode       *buf;
 754         int                     size = EXT2_INODE_SIZE(fs->super);
 755         struct ext2_inode_large *large_inode;
 756         errcode_t               retval;
 757         __u32                   t = fs->now ? fs->now : time(NULL);
 758
 759         if (!inode->i_ctime)
 760                 inode->i_ctime = t;
 761         if (!inode->i_mtime)
 762                 inode->i_mtime = t;
 763         if (!inode->i_atime)
 764                 inode->i_atime = t;
 765
 766         if (size == sizeof(struct ext2_inode))
 767                 return ext2fs_write_inode_full(fs, ino, inode,
 768                                                sizeof(struct ext2_inode));
 769
 770         buf = malloc(size);
 771         if (!buf)
 772                 return ENOMEM;
 773
 774         memset(buf, 0, size);
 775         *buf = *inode;
 776
 777         large_inode = (struct ext2_inode_large *) buf;
 778         large_inode->i_extra_isize = sizeof(struct ext2_inode_large) -
 779                 EXT2_GOOD_OLD_INODE_SIZE;
 780         if (!large_inode->i_crtime)
 781                 large_inode->i_crtime = t;
 782
 783         retval = ext2fs_write_inode_full(fs, ino, buf, size);
 784         free(buf);
 785         return retval;
 786 }
 787
 788
 789 errcode_t ext2fs_get_blocks(ext2_filsys fs, ext2_ino_t ino, blk_t *blocks)
 790 {
 791         struct ext2_inode       inode;
 792         int                     i;
 793         errcode_t               retval;
 794
 795         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 796
 797         if (ino > fs->super->s_inodes_count)
 798                 return EXT2_ET_BAD_INODE_NUM;
 799
 800         if (fs->get_blocks) {
 801                 if (!(*fs->get_blocks)(fs, ino, blocks))
 802                         return 0;
 803         }
 804         retval = ext2fs_read_inode(fs, ino, &inode);
 805         if (retval)
 806                 return retval;
 807         for (i=0; i < EXT2_N_BLOCKS; i++)
 808                 blocks[i] = inode.i_block[i];
 809         return 0;
 810 }
 811
 812 errcode_t ext2fs_check_directory(ext2_filsys fs, ext2_ino_t ino)
 813 {
 814         struct  ext2_inode      inode;
 815         errcode_t               retval;
 816
 817         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 818
 819         if (ino > fs->super->s_inodes_count)
 820                 return EXT2_ET_BAD_INODE_NUM;
 821
 822         if (fs->check_directory) {
 823                 retval = (fs->check_directory)(fs, ino);
 824                 if (retval != EXT2_ET_CALLBACK_NOTHANDLED)
 825                         return retval;
 826         }
 827         retval = ext2fs_read_inode(fs, ino, &inode);
 828         if (retval)
 829                 return retval;
 830         if (!LINUX_S_ISDIR(inode.i_mode))
 831                 return EXT2_ET_NO_DIRECTORY;
 832         return 0;
 833 }
 834