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         *ret_scan = scan;
 168         return 0;
 169 }
 170
 171 void ext2fs_close_inode_scan(ext2_inode_scan scan)
 172 {
 173         if (!scan || (scan->magic != EXT2_ET_MAGIC_INODE_SCAN))
 174                 return;
 175
 176         ext2fs_free_mem(&scan->inode_buffer);
 177         scan->inode_buffer = NULL;
 178         ext2fs_free_mem(&scan->temp_buffer);
 179         scan->temp_buffer = NULL;
 180         ext2fs_free_mem(&scan);
 181         return;
 182 }
 183
 184 void ext2fs_set_inode_callback(ext2_inode_scan scan,
 185                                errcode_t (*done_group)(ext2_filsys fs,
 186                                                        ext2_inode_scan scan,
 187                                                        dgrp_t group,
 188                                                        void * priv_data),
 189                                void *done_group_data)
 190 {
 191         if (!scan || (scan->magic != EXT2_ET_MAGIC_INODE_SCAN))
 192                 return;
 193
 194         scan->done_group = done_group;
 195         scan->done_group_data = done_group_data;
 196 }
 197
 198 int ext2fs_inode_scan_flags(ext2_inode_scan scan, int set_flags,
 199                             int clear_flags)
 200 {
 201         int     old_flags;
 202
 203         if (!scan || (scan->magic != EXT2_ET_MAGIC_INODE_SCAN))
 204                 return 0;
 205
 206         old_flags = scan->scan_flags;
 207         scan->scan_flags &= ~clear_flags;
 208         scan->scan_flags |= set_flags;
 209         return old_flags;
 210 }
 211
 212 /*
 213  * This function is called by ext2fs_get_next_inode when it needs to
 214  * get ready to read in a new blockgroup.
 215  */
 216 static errcode_t get_next_blockgroup(ext2_inode_scan scan)
 217 {
 218         scan->current_group++;
 219         scan->groups_left--;
 220
 221         scan->current_block = scan->fs->
 222                 group_desc[scan->current_group].bg_inode_table;
 223
 224         scan->current_inode = scan->current_group *
 225                 EXT2_INODES_PER_GROUP(scan->fs->super);
 226
 227         scan->bytes_left = 0;
 228         scan->inodes_left = EXT2_INODES_PER_GROUP(scan->fs->super);
 229         scan->blocks_left = scan->fs->inode_blocks_per_group;
 230         return 0;
 231 }
 232
 233 errcode_t ext2fs_inode_scan_goto_blockgroup(ext2_inode_scan scan,
 234                                             int group)
 235 {
 236         scan->current_group = group - 1;
 237         scan->groups_left = scan->fs->group_desc_count - group;
 238         return get_next_blockgroup(scan);
 239 }
 240
 241 /*
 242  * This function is called by get_next_blocks() to check for bad
 243  * blocks in the inode table.
 244  *
 245  * This function assumes that badblocks_list->list is sorted in
 246  * increasing order.
 247  */
 248 static errcode_t check_for_inode_bad_blocks(ext2_inode_scan scan,
 249                                             blk_t *num_blocks)
 250 {
 251         blk_t   blk = scan->current_block;
 252         badblocks_list  bb = scan->fs->badblocks;
 253
 254         /*
 255          * If the inode table is missing, then obviously there are no
 256          * bad blocks.  :-)
 257          */
 258         if (blk == 0)
 259                 return 0;
 260
 261         /*
 262          * If the current block is greater than the bad block listed
 263          * in the bad block list, then advance the pointer until this
 264          * is no longer the case.  If we run out of bad blocks, then
 265          * we don't need to do any more checking!
 266          */
 267         while (blk > bb->list[scan->bad_block_ptr]) {
 268                 if (++scan->bad_block_ptr >= bb->num) {
 269                         scan->scan_flags &= ~EXT2_SF_CHK_BADBLOCKS;
 270                         return 0;
 271                 }
 272         }
 273
 274         /*
 275          * If the current block is equal to the bad block listed in
 276          * the bad block list, then handle that one block specially.
 277          * (We could try to handle runs of bad blocks, but that
 278          * only increases CPU efficiency by a small amount, at the
 279          * expense of a huge expense of code complexity, and for an
 280          * uncommon case at that.)
 281          */
 282         if (blk == bb->list[scan->bad_block_ptr]) {
 283                 scan->scan_flags |= EXT2_SF_BAD_INODE_BLK;
 284                 *num_blocks = 1;
 285                 if (++scan->bad_block_ptr >= bb->num)
 286                         scan->scan_flags &= ~EXT2_SF_CHK_BADBLOCKS;
 287                 return 0;
 288         }
 289
 290         /*
 291          * If there is a bad block in the range that we're about to
 292          * read in, adjust the number of blocks to read so that we we
 293          * don't read in the bad block.  (Then the next block to read
 294          * will be the bad block, which is handled in the above case.)
 295          */
 296         if ((blk + *num_blocks) > bb->list[scan->bad_block_ptr])
 297                 *num_blocks = (int) (bb->list[scan->bad_block_ptr] - blk);
 298
 299         return 0;
 300 }
 301
 302 /*
 303  * This function is called by ext2fs_get_next_inode when it needs to
 304  * read in more blocks from the current blockgroup's inode table.
 305  */
 306 static errcode_t get_next_blocks(ext2_inode_scan scan)
 307 {
 308         blk_t           num_blocks;
 309         errcode_t       retval;
 310
 311         /*
 312          * Figure out how many blocks to read; we read at most
 313          * inode_buffer_blocks, and perhaps less if there aren't that
 314          * many blocks left to read.
 315          */
 316         num_blocks = scan->inode_buffer_blocks;
 317         if (num_blocks > scan->blocks_left)
 318                 num_blocks = scan->blocks_left;
 319
 320         /*
 321          * If the past block "read" was a bad block, then mark the
 322          * left-over extra bytes as also being bad.
 323          */
 324         if (scan->scan_flags & EXT2_SF_BAD_INODE_BLK) {
 325                 if (scan->bytes_left)
 326                         scan->scan_flags |= EXT2_SF_BAD_EXTRA_BYTES;
 327                 scan->scan_flags &= ~EXT2_SF_BAD_INODE_BLK;
 328         }
 329
 330         /*
 331          * Do inode bad block processing, if necessary.
 332          */
 333         if (scan->scan_flags & EXT2_SF_CHK_BADBLOCKS) {
 334                 retval = check_for_inode_bad_blocks(scan, &num_blocks);
 335                 if (retval)
 336                         return retval;
 337         }
 338
 339         if ((scan->scan_flags & EXT2_SF_BAD_INODE_BLK) ||
 340             (scan->current_block == 0)) {
 341                 memset(scan->inode_buffer, 0,
 342                        (size_t) num_blocks * scan->fs->blocksize);
 343         } else {
 344                 retval = io_channel_read_blk(scan->fs->io,
 345                                              scan->current_block,
 346                                              (int) num_blocks,
 347                                              scan->inode_buffer);
 348                 if (retval)
 349                         return EXT2_ET_NEXT_INODE_READ;
 350         }
 351         scan->ptr = scan->inode_buffer;
 352         scan->bytes_left = num_blocks * scan->fs->blocksize;
 353
 354         scan->blocks_left -= num_blocks;
 355         if (scan->current_block)
 356                 scan->current_block += num_blocks;
 357         return 0;
 358 }
 359
 360 #if 0
 361 /*
 362  * Returns 1 if the entire inode_buffer has a non-zero size and
 363  * contains all zeros.  (Not just deleted inodes, since that means
 364  * that part of the inode table was used at one point; we want all
 365  * zeros, which means that the inode table is pristine.)
 366  */
 367 static inline int is_empty_scan(ext2_inode_scan scan)
 368 {
 369         int     i;
 370
 371         if (scan->bytes_left == 0)
 372                 return 0;
 373
 374         for (i=0; i < scan->bytes_left; i++)
 375                 if (scan->ptr[i])
 376                         return 0;
 377         return 1;
 378 }
 379 #endif
 380
 381 errcode_t ext2fs_get_next_inode_full(ext2_inode_scan scan, ext2_ino_t *ino,
 382                                      struct ext2_inode *inode, int bufsize)
 383 {
 384         errcode_t       retval;
 385         int             extra_bytes = 0;
 386
 387         EXT2_CHECK_MAGIC(scan, EXT2_ET_MAGIC_INODE_SCAN);
 388
 389         /*
 390          * Do we need to start reading a new block group?
 391          */
 392         if (scan->inodes_left <= 0) {
 393         force_new_group:
 394                 if (scan->done_group) {
 395                         retval = (scan->done_group)
 396                                 (scan->fs, scan, scan->current_group,
 397                                  scan->done_group_data);
 398                         if (retval)
 399                                 return retval;
 400                 }
 401                 if (scan->groups_left <= 0) {
 402                         *ino = 0;
 403                         return 0;
 404                 }
 405                 retval = get_next_blockgroup(scan);
 406                 if (retval)
 407                         return retval;
 408         }
 409         /*
 410          * This is done outside the above if statement so that the
 411          * check can be done for block group #0.
 412          */
 413         if (scan->current_block == 0) {
 414                 if (scan->scan_flags & EXT2_SF_SKIP_MISSING_ITABLE) {
 415                         goto force_new_group;
 416                 } else
 417                         return EXT2_ET_MISSING_INODE_TABLE;
 418         }
 419
 420
 421         /*
 422          * Have we run out of space in the inode buffer?  If so, we
 423          * need to read in more blocks.
 424          */
 425         if (scan->bytes_left < scan->inode_size) {
 426                 memcpy(scan->temp_buffer, scan->ptr, scan->bytes_left);
 427                 extra_bytes = scan->bytes_left;
 428
 429                 retval = get_next_blocks(scan);
 430                 if (retval)
 431                         return retval;
 432 #if 0
 433                 /*
 434                  * XXX test  Need check for used inode somehow.
 435                  * (Note: this is hard.)
 436                  */
 437                 if (is_empty_scan(scan))
 438                         goto force_new_group;
 439 #endif
 440         }
 441
 442         retval = 0;
 443         if (extra_bytes) {
 444                 memcpy(scan->temp_buffer+extra_bytes, scan->ptr,
 445                        scan->inode_size - extra_bytes);
 446                 scan->ptr += scan->inode_size - extra_bytes;
 447                 scan->bytes_left -= scan->inode_size - extra_bytes;
 448
 449 #ifdef EXT2FS_ENABLE_SWAPFS
 450                 if ((scan->fs->flags & EXT2_FLAG_SWAP_BYTES) ||
 451                     (scan->fs->flags & EXT2_FLAG_SWAP_BYTES_READ))
 452                         ext2fs_swap_inode_full(scan->fs,
 453                                 (struct ext2_inode_large *) inode,
 454                                 (struct ext2_inode_large *) scan->temp_buffer,
 455                                 0, bufsize);
 456                 else
 457 #endif
 458                         *inode = *((struct ext2_inode *) scan->temp_buffer);
 459                 if (scan->scan_flags & EXT2_SF_BAD_EXTRA_BYTES)
 460                         retval = EXT2_ET_BAD_BLOCK_IN_INODE_TABLE;
 461                 scan->scan_flags &= ~EXT2_SF_BAD_EXTRA_BYTES;
 462         } else {
 463 #ifdef EXT2FS_ENABLE_SWAPFS
 464                 if ((scan->fs->flags & EXT2_FLAG_SWAP_BYTES) ||
 465                     (scan->fs->flags & EXT2_FLAG_SWAP_BYTES_READ))
 466                         ext2fs_swap_inode_full(scan->fs,
 467                                 (struct ext2_inode_large *) inode,
 468                                 (struct ext2_inode_large *) scan->ptr,
 469                                 0, bufsize);
 470                 else
 471 #endif
 472                         memcpy(inode, scan->ptr, bufsize);
 473                 scan->ptr += scan->inode_size;
 474                 scan->bytes_left -= scan->inode_size;
 475                 if (scan->scan_flags & EXT2_SF_BAD_INODE_BLK)
 476                         retval = EXT2_ET_BAD_BLOCK_IN_INODE_TABLE;
 477         }
 478
 479         scan->inodes_left--;
 480         scan->current_inode++;
 481         *ino = scan->current_inode;
 482         return retval;
 483 }
 484
 485 errcode_t ext2fs_get_next_inode(ext2_inode_scan scan, ext2_ino_t *ino,
 486                                 struct ext2_inode *inode)
 487 {
 488         return ext2fs_get_next_inode_full(scan, ino, inode,
 489                                                 sizeof(struct ext2_inode));
 490 }
 491
 492 /*
 493  * Functions to read and write a single inode.
 494  */
 495 errcode_t ext2fs_read_inode_full(ext2_filsys fs, ext2_ino_t ino,
 496                                  struct ext2_inode * inode, int bufsize)
 497 {
 498         unsigned long   group, block, block_nr, offset;
 499         char            *ptr;
 500         errcode_t       retval;
 501         int             clen, i, inodes_per_block, length;
 502         io_channel      io;
 503
 504         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 505
 506         /* Check to see if user has an override function */
 507         if (fs->read_inode) {
 508                 retval = (fs->read_inode)(fs, ino, inode);
 509                 if (retval != EXT2_ET_CALLBACK_NOTHANDLED)
 510                         return retval;
 511         }
 512         /* Create inode cache if not present */
 513         if (!fs->icache) {
 514                 retval = create_icache(fs);
 515                 if (retval)
 516                         return retval;
 517         }
 518         /* Check to see if it's in the inode cache */
 519         if (bufsize == sizeof(struct ext2_inode)) {
 520                 /* only old good inode can be retrieve from the cache */
 521                 for (i=0; i < fs->icache->cache_size; i++) {
 522                         if (fs->icache->cache[i].ino == ino) {
 523                                 *inode = fs->icache->cache[i].inode;
 524                                 return 0;
 525                         }
 526                 }
 527         }
 528         if ((ino == 0) || (ino > fs->super->s_inodes_count))
 529                 return EXT2_ET_BAD_INODE_NUM;
 530         if (fs->flags & EXT2_FLAG_IMAGE_FILE) {
 531                 inodes_per_block = fs->blocksize / EXT2_INODE_SIZE(fs->super);
 532                 block_nr = fs->image_header->offset_inode / fs->blocksize;
 533                 block_nr += (ino - 1) / inodes_per_block;
 534                 offset = ((ino - 1) % inodes_per_block) *
 535                         EXT2_INODE_SIZE(fs->super);
 536                 io = fs->image_io;
 537         } else {
 538                 group = (ino - 1) / EXT2_INODES_PER_GROUP(fs->super);
 539                 offset = ((ino - 1) % EXT2_INODES_PER_GROUP(fs->super)) *
 540                         EXT2_INODE_SIZE(fs->super);
 541                 block = offset >> EXT2_BLOCK_SIZE_BITS(fs->super);
 542                 if (!fs->group_desc[(unsigned)group].bg_inode_table)
 543                         return EXT2_ET_MISSING_INODE_TABLE;
 544                 block_nr = fs->group_desc[(unsigned)group].bg_inode_table +
 545                         block;
 546                 io = fs->io;
 547         }
 548         offset &= (EXT2_BLOCK_SIZE(fs->super) - 1);
 549
 550         length = EXT2_INODE_SIZE(fs->super);
 551         if (bufsize < length)
 552                 length = bufsize;
 553
 554         ptr = (char *) inode;
 555         while (length) {
 556                 clen = length;
 557                 if ((offset + length) > fs->blocksize)
 558                         clen = fs->blocksize - offset;
 559
 560                 if (block_nr != fs->icache->buffer_blk) {
 561                         retval = io_channel_read_blk(io, block_nr, 1,
 562                                                      fs->icache->buffer);
 563                         if (retval)
 564                                 return retval;
 565                         fs->icache->buffer_blk = block_nr;
 566                 }
 567
 568                 memcpy(ptr, ((char *) fs->icache->buffer) + (unsigned) offset,
 569                        clen);
 570
 571                 offset = 0;
 572                 length -= clen;
 573                 ptr += clen;
 574                 block_nr++;
 575         }
 576
 577 #ifdef EXT2FS_ENABLE_SWAPFS
 578         if ((fs->flags & EXT2_FLAG_SWAP_BYTES) ||
 579             (fs->flags & EXT2_FLAG_SWAP_BYTES_READ))
 580                 ext2fs_swap_inode_full(fs, (struct ext2_inode_large *) inode,
 581                                        (struct ext2_inode_large *) inode,
 582                                        0, length);
 583 #endif
 584
 585         /* Update the inode cache */
 586         fs->icache->cache_last = (fs->icache->cache_last + 1) %
 587                 fs->icache->cache_size;
 588         fs->icache->cache[fs->icache->cache_last].ino = ino;
 589         fs->icache->cache[fs->icache->cache_last].inode = *inode;
 590
 591         return 0;
 592 }
 593
 594 errcode_t ext2fs_read_inode(ext2_filsys fs, ext2_ino_t ino,
 595                             struct ext2_inode * inode)
 596 {
 597         return ext2fs_read_inode_full(fs, ino, inode,
 598                                         sizeof(struct ext2_inode));
 599 }
 600
 601 errcode_t ext2fs_write_inode_full(ext2_filsys fs, ext2_ino_t ino,
 602                                   struct ext2_inode * inode, int bufsize)
 603 {
 604         unsigned long group, block, block_nr, offset;
 605         errcode_t retval = 0;
 606         struct ext2_inode_large temp_inode, *w_inode;
 607         char *ptr;
 608         int clen, i, length;
 609
 610         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 611
 612         /* Check to see if user provided an override function */
 613         if (fs->write_inode) {
 614                 retval = (fs->write_inode)(fs, ino, inode);
 615                 if (retval != EXT2_ET_CALLBACK_NOTHANDLED)
 616                         return retval;
 617         }
 618
 619         /* Check to see if the inode cache needs to be updated */
 620         if (fs->icache) {
 621                 for (i=0; i < fs->icache->cache_size; i++) {
 622                         if (fs->icache->cache[i].ino == ino) {
 623                                 fs->icache->cache[i].inode = *inode;
 624                                 break;
 625                         }
 626                 }
 627         } else {
 628                 retval = create_icache(fs);
 629                 if (retval)
 630                         return retval;
 631         }
 632
 633         if (!(fs->flags & EXT2_FLAG_RW))
 634                 return EXT2_ET_RO_FILSYS;
 635
 636         if ((ino == 0) || (ino > fs->super->s_inodes_count))
 637                 return EXT2_ET_BAD_INODE_NUM;
 638
 639         length = bufsize;
 640         if (length < EXT2_INODE_SIZE(fs->super))
 641                 length = EXT2_INODE_SIZE(fs->super);
 642
 643         if (length > (int) sizeof(struct ext2_inode_large)) {
 644                 w_inode = malloc(length);
 645                 if (!w_inode)
 646                         return ENOMEM;
 647         } else
 648                 w_inode = &temp_inode;
 649         memset(w_inode, 0, length);
 650
 651 #ifdef EXT2FS_ENABLE_SWAPFS
 652         if ((fs->flags & EXT2_FLAG_SWAP_BYTES) ||
 653             (fs->flags & EXT2_FLAG_SWAP_BYTES_WRITE))
 654                 ext2fs_swap_inode_full(fs, w_inode,
 655                                        (struct ext2_inode_large *) inode,
 656                                        1, bufsize);
 657         else
 658 #endif
 659                 memcpy(w_inode, inode, bufsize);
 660
 661         group = (ino - 1) / EXT2_INODES_PER_GROUP(fs->super);
 662         offset = ((ino - 1) % EXT2_INODES_PER_GROUP(fs->super)) *
 663                 EXT2_INODE_SIZE(fs->super);
 664         block = offset >> EXT2_BLOCK_SIZE_BITS(fs->super);
 665         if (!fs->group_desc[(unsigned) group].bg_inode_table)
 666                 return EXT2_ET_MISSING_INODE_TABLE;
 667         block_nr = fs->group_desc[(unsigned) group].bg_inode_table + block;
 668
 669         offset &= (EXT2_BLOCK_SIZE(fs->super) - 1);
 670
 671         length = EXT2_INODE_SIZE(fs->super);
 672         if (length > bufsize)
 673                 length = bufsize;
 674
 675         ptr = (char *) w_inode;
 676
 677         while (length) {
 678                 clen = length;
 679                 if ((offset + length) > fs->blocksize)
 680                         clen = fs->blocksize - offset;
 681
 682                 if (fs->icache->buffer_blk != block_nr) {
 683                         retval = io_channel_read_blk(fs->io, block_nr, 1,
 684                                                      fs->icache->buffer);
 685                         if (retval)
 686                                 goto errout;
 687                         fs->icache->buffer_blk = block_nr;
 688                 }
 689
 690
 691                 memcpy((char *) fs->icache->buffer + (unsigned) offset,
 692                        ptr, clen);
 693
 694                 retval = io_channel_write_blk(fs->io, block_nr, 1,
 695                                               fs->icache->buffer);
 696                 if (retval)
 697                         goto errout;
 698
 699                 offset = 0;
 700                 ptr += clen;
 701                 length -= clen;
 702                 block_nr++;
 703         }
 704
 705         fs->flags |= EXT2_FLAG_CHANGED;
 706 errout:
 707         if (w_inode && w_inode != &temp_inode)
 708                 free(w_inode);
 709         return retval;
 710 }
 711
 712 errcode_t ext2fs_write_inode(ext2_filsys fs, ext2_ino_t ino,
 713                              struct ext2_inode *inode)
 714 {
 715         return ext2fs_write_inode_full(fs, ino, inode,
 716                                        sizeof(struct ext2_inode));
 717 }
 718
 719 /*
 720  * This function should be called when writing a new inode.  It makes
 721  * sure that extra part of large inodes is initialized properly.
 722  */
 723 errcode_t ext2fs_write_new_inode(ext2_filsys fs, ext2_ino_t ino,
 724                                  struct ext2_inode *inode)
 725 {
 726         struct ext2_inode       *buf;
 727         errcode_t               retval;
 728         int                     size = EXT2_INODE_SIZE(fs->super);
 729         struct ext2_inode_large *large_inode;
 730
 731         if (size == sizeof(struct ext2_inode))
 732                 return ext2fs_write_inode_full(fs, ino, inode,
 733                                                sizeof(struct ext2_inode));
 734
 735         buf = malloc(size);
 736         if (!buf)
 737                 return ENOMEM;
 738
 739         memset(buf, 0, size);
 740         *buf = *inode;
 741
 742         large_inode = (struct ext2_inode_large *) buf;
 743         large_inode->i_extra_isize = sizeof(struct ext2_inode_large) -
 744                 EXT2_GOOD_OLD_INODE_SIZE;
 745
 746         retval = ext2fs_write_inode_full(fs, ino, buf, size);
 747 }
 748
 749
 750 errcode_t ext2fs_get_blocks(ext2_filsys fs, ext2_ino_t ino, blk_t *blocks)
 751 {
 752         struct ext2_inode       inode;
 753         int                     i;
 754         errcode_t               retval;
 755
 756         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 757
 758         if (ino > fs->super->s_inodes_count)
 759                 return EXT2_ET_BAD_INODE_NUM;
 760
 761         if (fs->get_blocks) {
 762                 if (!(*fs->get_blocks)(fs, ino, blocks))
 763                         return 0;
 764         }
 765         retval = ext2fs_read_inode(fs, ino, &inode);
 766         if (retval)
 767                 return retval;
 768         for (i=0; i < EXT2_N_BLOCKS; i++)
 769                 blocks[i] = inode.i_block[i];
 770         return 0;
 771 }
 772
 773 errcode_t ext2fs_check_directory(ext2_filsys fs, ext2_ino_t ino)
 774 {
 775         struct  ext2_inode      inode;
 776         errcode_t               retval;
 777
 778         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 779
 780         if (ino > fs->super->s_inodes_count)
 781                 return EXT2_ET_BAD_INODE_NUM;
 782
 783         if (fs->check_directory) {
 784                 retval = (fs->check_directory)(fs, ino);
 785                 if (retval != EXT2_ET_CALLBACK_NOTHANDLED)
 786                         return retval;
 787         }
 788         retval = ext2fs_read_inode(fs, ino, &inode);
 789         if (retval)
 790                 return retval;
 791         if (!LINUX_S_ISDIR(inode.i_mode))
 792                 return EXT2_ET_NO_DIRECTORY;
 793         return 0;
 794 }
 795