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 WORDS_BIGENDIAN
 457                 memset(inode, 0, bufsize);
 458                 ext2fs_swap_inode_full(scan->fs,
 459                                (struct ext2_inode_large *) inode,
 460                                (struct ext2_inode_large *) scan->temp_buffer,
 461                                0, bufsize);
 462 #else
 463                 *inode = *((struct ext2_inode *) scan->temp_buffer);
 464 #endif
 465                 if (scan->scan_flags & EXT2_SF_BAD_EXTRA_BYTES)
 466                         retval = EXT2_ET_BAD_BLOCK_IN_INODE_TABLE;
 467                 scan->scan_flags &= ~EXT2_SF_BAD_EXTRA_BYTES;
 468         } else {
 469 #ifdef WORDS_BIGENDIAN
 470                 memset(inode, 0, bufsize);
 471                 ext2fs_swap_inode_full(scan->fs,
 472                                 (struct ext2_inode_large *) inode,
 473                                 (struct ext2_inode_large *) scan->ptr,
 474                                 0, bufsize);
 475 #else
 476                 memcpy(inode, scan->ptr, bufsize);
 477 #endif
 478                 scan->ptr += scan->inode_size;
 479                 scan->bytes_left -= scan->inode_size;
 480                 if (scan->scan_flags & EXT2_SF_BAD_INODE_BLK)
 481                         retval = EXT2_ET_BAD_BLOCK_IN_INODE_TABLE;
 482         }
 483
 484         scan->inodes_left--;
 485         scan->current_inode++;
 486         *ino = scan->current_inode;
 487         return retval;
 488 }
 489
 490 errcode_t ext2fs_get_next_inode(ext2_inode_scan scan, ext2_ino_t *ino,
 491                                 struct ext2_inode *inode)
 492 {
 493         return ext2fs_get_next_inode_full(scan, ino, inode,
 494                                                 sizeof(struct ext2_inode));
 495 }
 496
 497 /*
 498  * Functions to read and write a single inode.
 499  */
 500 errcode_t ext2fs_read_inode_full(ext2_filsys fs, ext2_ino_t ino,
 501                                  struct ext2_inode * inode, int bufsize)
 502 {
 503         unsigned long   group, block, block_nr, offset;
 504         char            *ptr;
 505         errcode_t       retval;
 506         int             clen, i, inodes_per_block, length;
 507         io_channel      io;
 508
 509         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 510
 511         /* Check to see if user has an override function */
 512         if (fs->read_inode) {
 513                 retval = (fs->read_inode)(fs, ino, inode);
 514                 if (retval != EXT2_ET_CALLBACK_NOTHANDLED)
 515                         return retval;
 516         }
 517         /* Create inode cache if not present */
 518         if (!fs->icache) {
 519                 retval = create_icache(fs);
 520                 if (retval)
 521                         return retval;
 522         }
 523         /* Check to see if it's in the inode cache */
 524         if (bufsize == sizeof(struct ext2_inode)) {
 525                 /* only old good inode can be retrieve from the cache */
 526                 for (i=0; i < fs->icache->cache_size; i++) {
 527                         if (fs->icache->cache[i].ino == ino) {
 528                                 *inode = fs->icache->cache[i].inode;
 529                                 return 0;
 530                         }
 531                 }
 532         }
 533         if ((ino == 0) || (ino > fs->super->s_inodes_count))
 534                 return EXT2_ET_BAD_INODE_NUM;
 535         if (fs->flags & EXT2_FLAG_IMAGE_FILE) {
 536                 inodes_per_block = fs->blocksize / EXT2_INODE_SIZE(fs->super);
 537                 block_nr = fs->image_header->offset_inode / fs->blocksize;
 538                 block_nr += (ino - 1) / inodes_per_block;
 539                 offset = ((ino - 1) % inodes_per_block) *
 540                         EXT2_INODE_SIZE(fs->super);
 541                 io = fs->image_io;
 542         } else {
 543                 group = (ino - 1) / EXT2_INODES_PER_GROUP(fs->super);
 544                 offset = ((ino - 1) % EXT2_INODES_PER_GROUP(fs->super)) *
 545                         EXT2_INODE_SIZE(fs->super);
 546                 block = offset >> EXT2_BLOCK_SIZE_BITS(fs->super);
 547                 if (!fs->group_desc[(unsigned)group].bg_inode_table)
 548                         return EXT2_ET_MISSING_INODE_TABLE;
 549                 block_nr = fs->group_desc[(unsigned)group].bg_inode_table +
 550                         block;
 551                 io = fs->io;
 552         }
 553         offset &= (EXT2_BLOCK_SIZE(fs->super) - 1);
 554
 555         length = EXT2_INODE_SIZE(fs->super);
 556         if (bufsize < length)
 557                 length = bufsize;
 558
 559         ptr = (char *) inode;
 560         while (length) {
 561                 clen = length;
 562                 if ((offset + length) > fs->blocksize)
 563                         clen = fs->blocksize - offset;
 564
 565                 if (block_nr != fs->icache->buffer_blk) {
 566                         retval = io_channel_read_blk(io, block_nr, 1,
 567                                                      fs->icache->buffer);
 568                         if (retval)
 569                                 return retval;
 570                         fs->icache->buffer_blk = block_nr;
 571                 }
 572
 573                 memcpy(ptr, ((char *) fs->icache->buffer) + (unsigned) offset,
 574                        clen);
 575
 576                 offset = 0;
 577                 length -= clen;
 578                 ptr += clen;
 579                 block_nr++;
 580         }
 581
 582 #ifdef WORDS_BIGENDIAN
 583         ext2fs_swap_inode_full(fs, (struct ext2_inode_large *) inode,
 584                                (struct ext2_inode_large *) inode,
 585                                0, bufsize);
 586 #endif
 587
 588         /* Update the inode cache */
 589         fs->icache->cache_last = (fs->icache->cache_last + 1) %
 590                 fs->icache->cache_size;
 591         fs->icache->cache[fs->icache->cache_last].ino = ino;
 592         fs->icache->cache[fs->icache->cache_last].inode = *inode;
 593
 594         return 0;
 595 }
 596
 597 errcode_t ext2fs_read_inode(ext2_filsys fs, ext2_ino_t ino,
 598                             struct ext2_inode * inode)
 599 {
 600         return ext2fs_read_inode_full(fs, ino, inode,
 601                                         sizeof(struct ext2_inode));
 602 }
 603
 604 errcode_t ext2fs_write_inode_full(ext2_filsys fs, ext2_ino_t ino,
 605                                   struct ext2_inode * inode, int bufsize)
 606 {
 607         unsigned long group, block, block_nr, offset;
 608         errcode_t retval = 0;
 609         struct ext2_inode_large temp_inode, *w_inode;
 610         char *ptr;
 611         int clen, i, length;
 612
 613         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 614
 615         /* Check to see if user provided an override function */
 616         if (fs->write_inode) {
 617                 retval = (fs->write_inode)(fs, ino, inode);
 618                 if (retval != EXT2_ET_CALLBACK_NOTHANDLED)
 619                         return retval;
 620         }
 621
 622         /* Check to see if the inode cache needs to be updated */
 623         if (fs->icache) {
 624                 for (i=0; i < fs->icache->cache_size; i++) {
 625                         if (fs->icache->cache[i].ino == ino) {
 626                                 fs->icache->cache[i].inode = *inode;
 627                                 break;
 628                         }
 629                 }
 630         } else {
 631                 retval = create_icache(fs);
 632                 if (retval)
 633                         return retval;
 634         }
 635
 636         if (!(fs->flags & EXT2_FLAG_RW))
 637                 return EXT2_ET_RO_FILSYS;
 638
 639         if ((ino == 0) || (ino > fs->super->s_inodes_count))
 640                 return EXT2_ET_BAD_INODE_NUM;
 641
 642         length = bufsize;
 643         if (length < EXT2_INODE_SIZE(fs->super))
 644                 length = EXT2_INODE_SIZE(fs->super);
 645
 646         if (length > (int) sizeof(struct ext2_inode_large)) {
 647                 w_inode = malloc(length);
 648                 if (!w_inode)
 649                         return ENOMEM;
 650         } else
 651                 w_inode = &temp_inode;
 652         memset(w_inode, 0, length);
 653
 654 #ifdef WORDS_BIGENDIAN
 655         ext2fs_swap_inode_full(fs, w_inode,
 656                                (struct ext2_inode_large *) inode,
 657                                1, bufsize);
 658 #else
 659         memcpy(w_inode, inode, bufsize);
 660 #endif
 661
 662         group = (ino - 1) / EXT2_INODES_PER_GROUP(fs->super);
 663         offset = ((ino - 1) % EXT2_INODES_PER_GROUP(fs->super)) *
 664                 EXT2_INODE_SIZE(fs->super);
 665         block = offset >> EXT2_BLOCK_SIZE_BITS(fs->super);
 666         if (!fs->group_desc[(unsigned) group].bg_inode_table) {
 667                 retval = EXT2_ET_MISSING_INODE_TABLE;
 668                 goto errout;
 669         }
 670         block_nr = fs->group_desc[(unsigned) group].bg_inode_table + block;
 671
 672         offset &= (EXT2_BLOCK_SIZE(fs->super) - 1);
 673
 674         length = EXT2_INODE_SIZE(fs->super);
 675         if (length > bufsize)
 676                 length = bufsize;
 677
 678         ptr = (char *) w_inode;
 679
 680         while (length) {
 681                 clen = length;
 682                 if ((offset + length) > fs->blocksize)
 683                         clen = fs->blocksize - offset;
 684
 685                 if (fs->icache->buffer_blk != block_nr) {
 686                         retval = io_channel_read_blk(fs->io, block_nr, 1,
 687                                                      fs->icache->buffer);
 688                         if (retval)
 689                                 goto errout;
 690                         fs->icache->buffer_blk = block_nr;
 691                 }
 692
 693
 694                 memcpy((char *) fs->icache->buffer + (unsigned) offset,
 695                        ptr, clen);
 696
 697                 retval = io_channel_write_blk(fs->io, block_nr, 1,
 698                                               fs->icache->buffer);
 699                 if (retval)
 700                         goto errout;
 701
 702                 offset = 0;
 703                 ptr += clen;
 704                 length -= clen;
 705                 block_nr++;
 706         }
 707
 708         fs->flags |= EXT2_FLAG_CHANGED;
 709 errout:
 710         if (w_inode && w_inode != &temp_inode)
 711                 free(w_inode);
 712         return retval;
 713 }
 714
 715 errcode_t ext2fs_write_inode(ext2_filsys fs, ext2_ino_t ino,
 716                              struct ext2_inode *inode)
 717 {
 718         return ext2fs_write_inode_full(fs, ino, inode,
 719                                        sizeof(struct ext2_inode));
 720 }
 721
 722 /*
 723  * This function should be called when writing a new inode.  It makes
 724  * sure that extra part of large inodes is initialized properly.
 725  */
 726 errcode_t ext2fs_write_new_inode(ext2_filsys fs, ext2_ino_t ino,
 727                                  struct ext2_inode *inode)
 728 {
 729         struct ext2_inode       *buf;
 730         int                     size = EXT2_INODE_SIZE(fs->super);
 731         struct ext2_inode_large *large_inode;
 732         errcode_t               retval;
 733
 734         if (size == sizeof(struct ext2_inode))
 735                 return ext2fs_write_inode_full(fs, ino, inode,
 736                                                sizeof(struct ext2_inode));
 737
 738         buf = malloc(size);
 739         if (!buf)
 740                 return ENOMEM;
 741
 742         memset(buf, 0, size);
 743         *buf = *inode;
 744
 745         large_inode = (struct ext2_inode_large *) buf;
 746         large_inode->i_extra_isize = sizeof(struct ext2_inode_large) -
 747                 EXT2_GOOD_OLD_INODE_SIZE;
 748
 749         retval = ext2fs_write_inode_full(fs, ino, buf, size);
 750         free(buf);
 751         return retval;
 752 }
 753
 754
 755 errcode_t ext2fs_get_blocks(ext2_filsys fs, ext2_ino_t ino, blk_t *blocks)
 756 {
 757         struct ext2_inode       inode;
 758         int                     i;
 759         errcode_t               retval;
 760
 761         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 762
 763         if (ino > fs->super->s_inodes_count)
 764                 return EXT2_ET_BAD_INODE_NUM;
 765
 766         if (fs->get_blocks) {
 767                 if (!(*fs->get_blocks)(fs, ino, blocks))
 768                         return 0;
 769         }
 770         retval = ext2fs_read_inode(fs, ino, &inode);
 771         if (retval)
 772                 return retval;
 773         for (i=0; i < EXT2_N_BLOCKS; i++)
 774                 blocks[i] = inode.i_block[i];
 775         return 0;
 776 }
 777
 778 errcode_t ext2fs_check_directory(ext2_filsys fs, ext2_ino_t ino)
 779 {
 780         struct  ext2_inode      inode;
 781         errcode_t               retval;
 782
 783         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 784
 785         if (ino > fs->super->s_inodes_count)
 786                 return EXT2_ET_BAD_INODE_NUM;
 787
 788         if (fs->check_directory) {
 789                 retval = (fs->check_directory)(fs, ino);
 790                 if (retval != EXT2_ET_CALLBACK_NOTHANDLED)
 791                         return retval;
 792         }
 793         retval = ext2fs_read_inode(fs, ino, &inode);
 794         if (retval)
 795                 return retval;
 796         if (!LINUX_S_ISDIR(inode.i_mode))
 797                 return EXT2_ET_NO_DIRECTORY;
 798         return 0;
 799 }
 800