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_mem(sizeof(struct ext2_inode_cache_ent)
  94                                 * fs->icache->cache_size,
  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_mem((size_t) (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         *ret_scan = scan;
 171         return 0;
 172 }
 173
 174 void ext2fs_close_inode_scan(ext2_inode_scan scan)
 175 {
 176         if (!scan || (scan->magic != EXT2_ET_MAGIC_INODE_SCAN))
 177                 return;
 178
 179         ext2fs_free_mem(&scan->inode_buffer);
 180         scan->inode_buffer = NULL;
 181         ext2fs_free_mem(&scan->temp_buffer);
 182         scan->temp_buffer = NULL;
 183         ext2fs_free_mem(&scan);
 184         return;
 185 }
 186
 187 void ext2fs_set_inode_callback(ext2_inode_scan scan,
 188                                errcode_t (*done_group)(ext2_filsys fs,
 189                                                        ext2_inode_scan scan,
 190                                                        dgrp_t group,
 191                                                        void * priv_data),
 192                                void *done_group_data)
 193 {
 194         if (!scan || (scan->magic != EXT2_ET_MAGIC_INODE_SCAN))
 195                 return;
 196
 197         scan->done_group = done_group;
 198         scan->done_group_data = done_group_data;
 199 }
 200
 201 int ext2fs_inode_scan_flags(ext2_inode_scan scan, int set_flags,
 202                             int clear_flags)
 203 {
 204         int     old_flags;
 205
 206         if (!scan || (scan->magic != EXT2_ET_MAGIC_INODE_SCAN))
 207                 return 0;
 208
 209         old_flags = scan->scan_flags;
 210         scan->scan_flags &= ~clear_flags;
 211         scan->scan_flags |= set_flags;
 212         return old_flags;
 213 }
 214
 215 /*
 216  * This function is called by ext2fs_get_next_inode when it needs to
 217  * get ready to read in a new blockgroup.
 218  */
 219 static errcode_t get_next_blockgroup(ext2_inode_scan scan)
 220 {
 221         scan->current_group++;
 222         scan->groups_left--;
 223
 224         scan->current_block = scan->fs->
 225                 group_desc[scan->current_group].bg_inode_table;
 226
 227         scan->current_inode = scan->current_group *
 228                 EXT2_INODES_PER_GROUP(scan->fs->super);
 229
 230         scan->bytes_left = 0;
 231         scan->inodes_left = EXT2_INODES_PER_GROUP(scan->fs->super);
 232         scan->blocks_left = scan->fs->inode_blocks_per_group;
 233         return 0;
 234 }
 235
 236 errcode_t ext2fs_inode_scan_goto_blockgroup(ext2_inode_scan scan,
 237                                             int group)
 238 {
 239         scan->current_group = group - 1;
 240         scan->groups_left = scan->fs->group_desc_count - group;
 241         return get_next_blockgroup(scan);
 242 }
 243
 244 /*
 245  * This function is called by get_next_blocks() to check for bad
 246  * blocks in the inode table.
 247  *
 248  * This function assumes that badblocks_list->list is sorted in
 249  * increasing order.
 250  */
 251 static errcode_t check_for_inode_bad_blocks(ext2_inode_scan scan,
 252                                             blk_t *num_blocks)
 253 {
 254         blk_t   blk = scan->current_block;
 255         badblocks_list  bb = scan->fs->badblocks;
 256
 257         /*
 258          * If the inode table is missing, then obviously there are no
 259          * bad blocks.  :-)
 260          */
 261         if (blk == 0)
 262                 return 0;
 263
 264         /*
 265          * If the current block is greater than the bad block listed
 266          * in the bad block list, then advance the pointer until this
 267          * is no longer the case.  If we run out of bad blocks, then
 268          * we don't need to do any more checking!
 269          */
 270         while (blk > bb->list[scan->bad_block_ptr]) {
 271                 if (++scan->bad_block_ptr >= bb->num) {
 272                         scan->scan_flags &= ~EXT2_SF_CHK_BADBLOCKS;
 273                         return 0;
 274                 }
 275         }
 276
 277         /*
 278          * If the current block is equal to the bad block listed in
 279          * the bad block list, then handle that one block specially.
 280          * (We could try to handle runs of bad blocks, but that
 281          * only increases CPU efficiency by a small amount, at the
 282          * expense of a huge expense of code complexity, and for an
 283          * uncommon case at that.)
 284          */
 285         if (blk == bb->list[scan->bad_block_ptr]) {
 286                 scan->scan_flags |= EXT2_SF_BAD_INODE_BLK;
 287                 *num_blocks = 1;
 288                 if (++scan->bad_block_ptr >= bb->num)
 289                         scan->scan_flags &= ~EXT2_SF_CHK_BADBLOCKS;
 290                 return 0;
 291         }
 292
 293         /*
 294          * If there is a bad block in the range that we're about to
 295          * read in, adjust the number of blocks to read so that we we
 296          * don't read in the bad block.  (Then the next block to read
 297          * will be the bad block, which is handled in the above case.)
 298          */
 299         if ((blk + *num_blocks) > bb->list[scan->bad_block_ptr])
 300                 *num_blocks = (int) (bb->list[scan->bad_block_ptr] - blk);
 301
 302         return 0;
 303 }
 304
 305 /*
 306  * This function is called by ext2fs_get_next_inode when it needs to
 307  * read in more blocks from the current blockgroup's inode table.
 308  */
 309 static errcode_t get_next_blocks(ext2_inode_scan scan)
 310 {
 311         blk_t           num_blocks;
 312         errcode_t       retval;
 313
 314         /*
 315          * Figure out how many blocks to read; we read at most
 316          * inode_buffer_blocks, and perhaps less if there aren't that
 317          * many blocks left to read.
 318          */
 319         num_blocks = scan->inode_buffer_blocks;
 320         if (num_blocks > scan->blocks_left)
 321                 num_blocks = scan->blocks_left;
 322
 323         /*
 324          * If the past block "read" was a bad block, then mark the
 325          * left-over extra bytes as also being bad.
 326          */
 327         if (scan->scan_flags & EXT2_SF_BAD_INODE_BLK) {
 328                 if (scan->bytes_left)
 329                         scan->scan_flags |= EXT2_SF_BAD_EXTRA_BYTES;
 330                 scan->scan_flags &= ~EXT2_SF_BAD_INODE_BLK;
 331         }
 332
 333         /*
 334          * Do inode bad block processing, if necessary.
 335          */
 336         if (scan->scan_flags & EXT2_SF_CHK_BADBLOCKS) {
 337                 retval = check_for_inode_bad_blocks(scan, &num_blocks);
 338                 if (retval)
 339                         return retval;
 340         }
 341
 342         if ((scan->scan_flags & EXT2_SF_BAD_INODE_BLK) ||
 343             (scan->current_block == 0)) {
 344                 memset(scan->inode_buffer, 0,
 345                        (size_t) num_blocks * scan->fs->blocksize);
 346         } else {
 347                 retval = io_channel_read_blk(scan->fs->io,
 348                                              scan->current_block,
 349                                              (int) num_blocks,
 350                                              scan->inode_buffer);
 351                 if (retval)
 352                         return EXT2_ET_NEXT_INODE_READ;
 353         }
 354         scan->ptr = scan->inode_buffer;
 355         scan->bytes_left = num_blocks * scan->fs->blocksize;
 356
 357         scan->blocks_left -= num_blocks;
 358         if (scan->current_block)
 359                 scan->current_block += num_blocks;
 360         return 0;
 361 }
 362
 363 #if 0
 364 /*
 365  * Returns 1 if the entire inode_buffer has a non-zero size and
 366  * contains all zeros.  (Not just deleted inodes, since that means
 367  * that part of the inode table was used at one point; we want all
 368  * zeros, which means that the inode table is pristine.)
 369  */
 370 static inline int is_empty_scan(ext2_inode_scan scan)
 371 {
 372         int     i;
 373
 374         if (scan->bytes_left == 0)
 375                 return 0;
 376
 377         for (i=0; i < scan->bytes_left; i++)
 378                 if (scan->ptr[i])
 379                         return 0;
 380         return 1;
 381 }
 382 #endif
 383
 384 errcode_t ext2fs_get_next_inode_full(ext2_inode_scan scan, ext2_ino_t *ino,
 385                                      struct ext2_inode *inode, int bufsize)
 386 {
 387         errcode_t       retval;
 388         int             extra_bytes = 0;
 389
 390         EXT2_CHECK_MAGIC(scan, EXT2_ET_MAGIC_INODE_SCAN);
 391
 392         /*
 393          * Do we need to start reading a new block group?
 394          */
 395         if (scan->inodes_left <= 0) {
 396         force_new_group:
 397                 if (scan->done_group) {
 398                         retval = (scan->done_group)
 399                                 (scan->fs, scan, scan->current_group,
 400                                  scan->done_group_data);
 401                         if (retval)
 402                                 return retval;
 403                 }
 404                 if (scan->groups_left <= 0) {
 405                         *ino = 0;
 406                         return 0;
 407                 }
 408                 retval = get_next_blockgroup(scan);
 409                 if (retval)
 410                         return retval;
 411         }
 412         /*
 413          * These checks are done outside the above if statement so
 414          * they can be done for block group #0.
 415          */
 416         if ((scan->scan_flags & EXT2_SF_DO_LAZY) &&
 417             (scan->fs->group_desc[scan->current_group].bg_flags &
 418              EXT2_BG_INODE_UNINIT))
 419                 goto force_new_group;
 420         if (scan->current_block == 0) {
 421                 if (scan->scan_flags & EXT2_SF_SKIP_MISSING_ITABLE) {
 422                         goto force_new_group;
 423                 } else
 424                         return EXT2_ET_MISSING_INODE_TABLE;
 425         }
 426
 427
 428         /*
 429          * Have we run out of space in the inode buffer?  If so, we
 430          * need to read in more blocks.
 431          */
 432         if (scan->bytes_left < scan->inode_size) {
 433                 memcpy(scan->temp_buffer, scan->ptr, scan->bytes_left);
 434                 extra_bytes = scan->bytes_left;
 435
 436                 retval = get_next_blocks(scan);
 437                 if (retval)
 438                         return retval;
 439 #if 0
 440                 /*
 441                  * XXX test  Need check for used inode somehow.
 442                  * (Note: this is hard.)
 443                  */
 444                 if (is_empty_scan(scan))
 445                         goto force_new_group;
 446 #endif
 447         }
 448
 449         retval = 0;
 450         if (extra_bytes) {
 451                 memcpy(scan->temp_buffer+extra_bytes, scan->ptr,
 452                        scan->inode_size - extra_bytes);
 453                 scan->ptr += scan->inode_size - extra_bytes;
 454                 scan->bytes_left -= scan->inode_size - extra_bytes;
 455
 456 #ifdef EXT2FS_ENABLE_SWAPFS
 457                 if ((scan->fs->flags & EXT2_FLAG_SWAP_BYTES) ||
 458                     (scan->fs->flags & EXT2_FLAG_SWAP_BYTES_READ))
 459                         ext2fs_swap_inode_full(scan->fs,
 460                                 (struct ext2_inode_large *) inode,
 461                                 (struct ext2_inode_large *) scan->temp_buffer,
 462                                 0, bufsize);
 463                 else
 464 #endif
 465                         *inode = *((struct ext2_inode *) scan->temp_buffer);
 466                 if (scan->scan_flags & EXT2_SF_BAD_EXTRA_BYTES)
 467                         retval = EXT2_ET_BAD_BLOCK_IN_INODE_TABLE;
 468                 scan->scan_flags &= ~EXT2_SF_BAD_EXTRA_BYTES;
 469         } else {
 470 #ifdef EXT2FS_ENABLE_SWAPFS
 471                 if ((scan->fs->flags & EXT2_FLAG_SWAP_BYTES) ||
 472                     (scan->fs->flags & EXT2_FLAG_SWAP_BYTES_READ))
 473                         ext2fs_swap_inode_full(scan->fs,
 474                                 (struct ext2_inode_large *) inode,
 475                                 (struct ext2_inode_large *) scan->ptr,
 476                                 0, bufsize);
 477                 else
 478 #endif
 479                         memcpy(inode, scan->ptr, bufsize);
 480                 scan->ptr += scan->inode_size;
 481                 scan->bytes_left -= scan->inode_size;
 482                 if (scan->scan_flags & EXT2_SF_BAD_INODE_BLK)
 483                         retval = EXT2_ET_BAD_BLOCK_IN_INODE_TABLE;
 484         }
 485
 486         scan->inodes_left--;
 487         scan->current_inode++;
 488         *ino = scan->current_inode;
 489         return retval;
 490 }
 491
 492 errcode_t ext2fs_get_next_inode(ext2_inode_scan scan, ext2_ino_t *ino,
 493                                 struct ext2_inode *inode)
 494 {
 495         return ext2fs_get_next_inode_full(scan, ino, inode,
 496                                                 sizeof(struct ext2_inode));
 497 }
 498
 499 /*
 500  * Functions to read and write a single inode.
 501  */
 502 errcode_t ext2fs_read_inode_full(ext2_filsys fs, ext2_ino_t ino,
 503                                  struct ext2_inode * inode, int bufsize)
 504 {
 505         unsigned long   group, block, block_nr, offset;
 506         char            *ptr;
 507         errcode_t       retval;
 508         int             clen, i, inodes_per_block, length;
 509         io_channel      io;
 510
 511         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 512
 513         /* Check to see if user has an override function */
 514         if (fs->read_inode) {
 515                 retval = (fs->read_inode)(fs, ino, inode);
 516                 if (retval != EXT2_ET_CALLBACK_NOTHANDLED)
 517                         return retval;
 518         }
 519         /* Create inode cache if not present */
 520         if (!fs->icache) {
 521                 retval = create_icache(fs);
 522                 if (retval)
 523                         return retval;
 524         }
 525         /* Check to see if it's in the inode cache */
 526         if (bufsize == sizeof(struct ext2_inode)) {
 527                 /* only old good inode can be retrieve from the cache */
 528                 for (i=0; i < fs->icache->cache_size; i++) {
 529                         if (fs->icache->cache[i].ino == ino) {
 530                                 *inode = fs->icache->cache[i].inode;
 531                                 return 0;
 532                         }
 533                 }
 534         }
 535         if ((ino == 0) || (ino > fs->super->s_inodes_count))
 536                 return EXT2_ET_BAD_INODE_NUM;
 537         if (fs->flags & EXT2_FLAG_IMAGE_FILE) {
 538                 inodes_per_block = fs->blocksize / EXT2_INODE_SIZE(fs->super);
 539                 block_nr = fs->image_header->offset_inode / fs->blocksize;
 540                 block_nr += (ino - 1) / inodes_per_block;
 541                 offset = ((ino - 1) % inodes_per_block) *
 542                         EXT2_INODE_SIZE(fs->super);
 543                 io = fs->image_io;
 544         } else {
 545                 group = (ino - 1) / EXT2_INODES_PER_GROUP(fs->super);
 546                 offset = ((ino - 1) % EXT2_INODES_PER_GROUP(fs->super)) *
 547                         EXT2_INODE_SIZE(fs->super);
 548                 block = offset >> EXT2_BLOCK_SIZE_BITS(fs->super);
 549                 if (!fs->group_desc[(unsigned)group].bg_inode_table)
 550                         return EXT2_ET_MISSING_INODE_TABLE;
 551                 block_nr = fs->group_desc[(unsigned)group].bg_inode_table +
 552                         block;
 553                 io = fs->io;
 554         }
 555         offset &= (EXT2_BLOCK_SIZE(fs->super) - 1);
 556
 557         length = EXT2_INODE_SIZE(fs->super);
 558         if (bufsize < length)
 559                 length = bufsize;
 560
 561         ptr = (char *) inode;
 562         while (length) {
 563                 clen = length;
 564                 if ((offset + length) > fs->blocksize)
 565                         clen = fs->blocksize - offset;
 566
 567                 if (block_nr != fs->icache->buffer_blk) {
 568                         retval = io_channel_read_blk(io, block_nr, 1,
 569                                                      fs->icache->buffer);
 570                         if (retval)
 571                                 return retval;
 572                         fs->icache->buffer_blk = block_nr;
 573                 }
 574
 575                 memcpy(ptr, ((char *) fs->icache->buffer) + (unsigned) offset,
 576                        clen);
 577
 578                 offset = 0;
 579                 length -= clen;
 580                 ptr += clen;
 581                 block_nr++;
 582         }
 583
 584 #ifdef EXT2FS_ENABLE_SWAPFS
 585         if ((fs->flags & EXT2_FLAG_SWAP_BYTES) ||
 586             (fs->flags & EXT2_FLAG_SWAP_BYTES_READ))
 587                 ext2fs_swap_inode_full(fs, (struct ext2_inode_large *) inode,
 588                                        (struct ext2_inode_large *) inode,
 589                                        0, length);
 590 #endif
 591
 592         /* Update the inode cache */
 593         fs->icache->cache_last = (fs->icache->cache_last + 1) %
 594                 fs->icache->cache_size;
 595         fs->icache->cache[fs->icache->cache_last].ino = ino;
 596         fs->icache->cache[fs->icache->cache_last].inode = *inode;
 597
 598         return 0;
 599 }
 600
 601 errcode_t ext2fs_read_inode(ext2_filsys fs, ext2_ino_t ino,
 602                             struct ext2_inode * inode)
 603 {
 604         return ext2fs_read_inode_full(fs, ino, inode,
 605                                         sizeof(struct ext2_inode));
 606 }
 607
 608 errcode_t ext2fs_write_inode_full(ext2_filsys fs, ext2_ino_t ino,
 609                                   struct ext2_inode * inode, int bufsize)
 610 {
 611         unsigned long group, block, block_nr, offset;
 612         errcode_t retval = 0;
 613         struct ext2_inode_large temp_inode, *w_inode;
 614         char *ptr;
 615         int clen, i, length;
 616
 617         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 618
 619         /* Check to see if user provided an override function */
 620         if (fs->write_inode) {
 621                 retval = (fs->write_inode)(fs, ino, inode);
 622                 if (retval != EXT2_ET_CALLBACK_NOTHANDLED)
 623                         return retval;
 624         }
 625
 626         /* Check to see if the inode cache needs to be updated */
 627         if (fs->icache) {
 628                 for (i=0; i < fs->icache->cache_size; i++) {
 629                         if (fs->icache->cache[i].ino == ino) {
 630                                 fs->icache->cache[i].inode = *inode;
 631                                 break;
 632                         }
 633                 }
 634         } else {
 635                 retval = create_icache(fs);
 636                 if (retval)
 637                         return retval;
 638         }
 639
 640         if (!(fs->flags & EXT2_FLAG_RW))
 641                 return EXT2_ET_RO_FILSYS;
 642
 643         if ((ino == 0) || (ino > fs->super->s_inodes_count))
 644                 return EXT2_ET_BAD_INODE_NUM;
 645
 646         length = bufsize;
 647         if (length < EXT2_INODE_SIZE(fs->super))
 648                 length = EXT2_INODE_SIZE(fs->super);
 649
 650         if (length > (int) sizeof(struct ext2_inode_large)) {
 651                 w_inode = malloc(length);
 652                 if (!w_inode)
 653                         return ENOMEM;
 654         } else
 655                 w_inode = &temp_inode;
 656         memset(w_inode, 0, length);
 657
 658 #ifdef EXT2FS_ENABLE_SWAPFS
 659         if ((fs->flags & EXT2_FLAG_SWAP_BYTES) ||
 660             (fs->flags & EXT2_FLAG_SWAP_BYTES_WRITE))
 661                 ext2fs_swap_inode_full(fs, w_inode,
 662                                        (struct ext2_inode_large *) inode,
 663                                        1, bufsize);
 664         else
 665 #endif
 666                 memcpy(w_inode, inode, bufsize);
 667
 668         group = (ino - 1) / EXT2_INODES_PER_GROUP(fs->super);
 669         offset = ((ino - 1) % EXT2_INODES_PER_GROUP(fs->super)) *
 670                 EXT2_INODE_SIZE(fs->super);
 671         block = offset >> EXT2_BLOCK_SIZE_BITS(fs->super);
 672         if (!fs->group_desc[(unsigned) group].bg_inode_table) {
 673                 retval = EXT2_ET_MISSING_INODE_TABLE;
 674                 goto errout;
 675         }
 676         block_nr = fs->group_desc[(unsigned) group].bg_inode_table + block;
 677
 678         offset &= (EXT2_BLOCK_SIZE(fs->super) - 1);
 679
 680         length = EXT2_INODE_SIZE(fs->super);
 681         if (length > bufsize)
 682                 length = bufsize;
 683
 684         ptr = (char *) w_inode;
 685
 686         while (length) {
 687                 clen = length;
 688                 if ((offset + length) > fs->blocksize)
 689                         clen = fs->blocksize - offset;
 690
 691                 if (fs->icache->buffer_blk != block_nr) {
 692                         retval = io_channel_read_blk(fs->io, block_nr, 1,
 693                                                      fs->icache->buffer);
 694                         if (retval)
 695                                 goto errout;
 696                         fs->icache->buffer_blk = block_nr;
 697                 }
 698
 699
 700                 memcpy((char *) fs->icache->buffer + (unsigned) offset,
 701                        ptr, clen);
 702
 703                 retval = io_channel_write_blk(fs->io, block_nr, 1,
 704                                               fs->icache->buffer);
 705                 if (retval)
 706                         goto errout;
 707
 708                 offset = 0;
 709                 ptr += clen;
 710                 length -= clen;
 711                 block_nr++;
 712         }
 713
 714         fs->flags |= EXT2_FLAG_CHANGED;
 715 errout:
 716         if (w_inode && w_inode != &temp_inode)
 717                 free(w_inode);
 718         return retval;
 719 }
 720
 721 errcode_t ext2fs_write_inode(ext2_filsys fs, ext2_ino_t ino,
 722                              struct ext2_inode *inode)
 723 {
 724         return ext2fs_write_inode_full(fs, ino, inode,
 725                                        sizeof(struct ext2_inode));
 726 }
 727
 728 /*
 729  * This function should be called when writing a new inode.  It makes
 730  * sure that extra part of large inodes is initialized properly.
 731  */
 732 errcode_t ext2fs_write_new_inode(ext2_filsys fs, ext2_ino_t ino,
 733                                  struct ext2_inode *inode)
 734 {
 735         struct ext2_inode       *buf;
 736         int                     size = EXT2_INODE_SIZE(fs->super);
 737         struct ext2_inode_large *large_inode;
 738         errcode_t               retval;
 739
 740         if (size == sizeof(struct ext2_inode))
 741                 return ext2fs_write_inode_full(fs, ino, inode,
 742                                                sizeof(struct ext2_inode));
 743
 744         buf = malloc(size);
 745         if (!buf)
 746                 return ENOMEM;
 747
 748         memset(buf, 0, size);
 749         *buf = *inode;
 750
 751         large_inode = (struct ext2_inode_large *) buf;
 752         large_inode->i_extra_isize = sizeof(struct ext2_inode_large) -
 753                 EXT2_GOOD_OLD_INODE_SIZE;
 754
 755         retval = ext2fs_write_inode_full(fs, ino, buf, size);
 756         free(buf);
 757         return retval;
 758 }
 759
 760
 761 errcode_t ext2fs_get_blocks(ext2_filsys fs, ext2_ino_t ino, blk_t *blocks)
 762 {
 763         struct ext2_inode       inode;
 764         int                     i;
 765         errcode_t               retval;
 766
 767         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 768
 769         if (ino > fs->super->s_inodes_count)
 770                 return EXT2_ET_BAD_INODE_NUM;
 771
 772         if (fs->get_blocks) {
 773                 if (!(*fs->get_blocks)(fs, ino, blocks))
 774                         return 0;
 775         }
 776         retval = ext2fs_read_inode(fs, ino, &inode);
 777         if (retval)
 778                 return retval;
 779         for (i=0; i < EXT2_N_BLOCKS; i++)
 780                 blocks[i] = inode.i_block[i];
 781         return 0;
 782 }
 783
 784 errcode_t ext2fs_check_directory(ext2_filsys fs, ext2_ino_t ino)
 785 {
 786         struct  ext2_inode      inode;
 787         errcode_t               retval;
 788
 789         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 790
 791         if (ino > fs->super->s_inodes_count)
 792                 return EXT2_ET_BAD_INODE_NUM;
 793
 794         if (fs->check_directory) {
 795                 retval = (fs->check_directory)(fs, ino);
 796                 if (retval != EXT2_ET_CALLBACK_NOTHANDLED)
 797                         return retval;
 798         }
 799         retval = ext2fs_read_inode(fs, ino, &inode);
 800         if (retval)
 801                 return retval;
 802         if (!LINUX_S_ISDIR(inode.i_mode))
 803                 return EXT2_ET_NO_DIRECTORY;
 804         return 0;
 805 }
 806