lib/ext2fs/rw_bitmaps.c

   1 /*
   2  * rw_bitmaps.c --- routines to read and write the  inode and block bitmaps.
   3  *
   4  * Copyright (C) 1993, 1994, 1994, 1996 Theodore Ts'o.
   5  *
   6  * %Begin-Header%
   7  * This file may be redistributed under the terms of the GNU Library
   8  * General Public License, version 2.
   9  * %End-Header%
  10  */
  11
  12 #include "config.h"
  13 #include <stdio.h>
  14 #include <string.h>
  15 #if HAVE_UNISTD_H
  16 #include <unistd.h>
  17 #endif
  18 #include <fcntl.h>
  19 #include <time.h>
  20 #ifdef HAVE_SYS_STAT_H
  21 #include <sys/stat.h>
  22 #endif
  23 #ifdef HAVE_SYS_TYPES_H
  24 #include <sys/types.h>
  25 #endif
  26
  27 #include "ext2_fs.h"
  28 #include "ext2fs.h"
  29 #include "e2image.h"
  30
  31 static errcode_t write_bitmaps(ext2_filsys fs, int do_inode, int do_block)
  32 {
  33         dgrp_t          i;
  34         unsigned int    j;
  35         int             block_nbytes, inode_nbytes;
  36         unsigned int    nbits;
  37         errcode_t       retval;
  38         char            *block_buf = NULL, *inode_buf = NULL;
  39         int             csum_flag;
  40         blk64_t         blk;
  41         blk64_t         blk_itr = EXT2FS_B2C(fs, fs->super->s_first_data_block);
  42         ext2_ino_t      ino_itr = 1;
  43
  44         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
  45
  46         if (!(fs->flags & EXT2_FLAG_RW))
  47                 return EXT2_ET_RO_FILSYS;
  48
  49         csum_flag = ext2fs_has_group_desc_csum(fs);
  50
  51         inode_nbytes = block_nbytes = 0;
  52         if (do_block) {
  53                 block_nbytes = EXT2_CLUSTERS_PER_GROUP(fs->super) / 8;
  54                 retval = io_channel_alloc_buf(fs->io, 0, &block_buf);
  55                 if (retval)
  56                         goto errout;
  57                 memset(block_buf, 0xff, fs->blocksize);
  58         }
  59         if (do_inode) {
  60                 inode_nbytes = (size_t)
  61                         ((EXT2_INODES_PER_GROUP(fs->super)+7) / 8);
  62                 retval = io_channel_alloc_buf(fs->io, 0, &inode_buf);
  63                 if (retval)
  64                         goto errout;
  65                 memset(inode_buf, 0xff, fs->blocksize);
  66         }
  67
  68         for (i = 0; i < fs->group_desc_count; i++) {
  69                 if (!do_block)
  70                         goto skip_block_bitmap;
  71
  72                 if (csum_flag && ext2fs_bg_flags_test(fs, i, EXT2_BG_BLOCK_UNINIT)
  73                     )
  74                         goto skip_this_block_bitmap;
  75
  76                 retval = ext2fs_get_block_bitmap_range2(fs->block_map,
  77                                 blk_itr, block_nbytes << 3, block_buf);
  78                 if (retval)
  79                         goto errout;
  80
  81                 if (i == fs->group_desc_count - 1) {
  82                         /* Force bitmap padding for the last group */
  83                         nbits = EXT2FS_NUM_B2C(fs,
  84                                 ((ext2fs_blocks_count(fs->super)
  85                                   - (__u64) fs->super->s_first_data_block)
  86                                  % (__u64) EXT2_BLOCKS_PER_GROUP(fs->super)));
  87                         if (nbits)
  88                                 for (j = nbits; j < fs->blocksize * 8; j++)
  89                                         ext2fs_set_bit(j, block_buf);
  90                 }
  91
  92                 retval = ext2fs_block_bitmap_csum_set(fs, i, block_buf,
  93                                                       block_nbytes);
  94                 if (retval)
  95                         return retval;
  96                 ext2fs_group_desc_csum_set(fs, i);
  97                 fs->flags |= EXT2_FLAG_DIRTY;
  98
  99                 blk = ext2fs_block_bitmap_loc(fs, i);
 100                 if (blk) {
 101                         retval = io_channel_write_blk64(fs->io, blk, 1,
 102                                                         block_buf);
 103                         if (retval) {
 104                                 retval = EXT2_ET_BLOCK_BITMAP_WRITE;
 105                                 goto errout;
 106                         }
 107                 }
 108         skip_this_block_bitmap:
 109                 blk_itr += block_nbytes << 3;
 110         skip_block_bitmap:
 111
 112                 if (!do_inode)
 113                         continue;
 114
 115                 if (csum_flag && ext2fs_bg_flags_test(fs, i, EXT2_BG_INODE_UNINIT)
 116                     )
 117                         goto skip_this_inode_bitmap;
 118
 119                 retval = ext2fs_get_inode_bitmap_range2(fs->inode_map,
 120                                 ino_itr, inode_nbytes << 3, inode_buf);
 121                 if (retval)
 122                         goto errout;
 123
 124                 retval = ext2fs_inode_bitmap_csum_set(fs, i, inode_buf,
 125                                                       inode_nbytes);
 126                 if (retval)
 127                         goto errout;
 128                 ext2fs_group_desc_csum_set(fs, i);
 129                 fs->flags |= EXT2_FLAG_DIRTY;
 130
 131                 blk = ext2fs_inode_bitmap_loc(fs, i);
 132                 if (blk) {
 133                         retval = io_channel_write_blk64(fs->io, blk, 1,
 134                                                       inode_buf);
 135                         if (retval) {
 136                                 retval = EXT2_ET_INODE_BITMAP_WRITE;
 137                                 goto errout;
 138                         }
 139                 }
 140         skip_this_inode_bitmap:
 141                 ino_itr += inode_nbytes << 3;
 142
 143         }
 144         if (do_block) {
 145                 fs->flags &= ~EXT2_FLAG_BB_DIRTY;
 146                 ext2fs_free_mem(&block_buf);
 147         }
 148         if (do_inode) {
 149                 fs->flags &= ~EXT2_FLAG_IB_DIRTY;
 150                 ext2fs_free_mem(&inode_buf);
 151         }
 152         return 0;
 153 errout:
 154         if (inode_buf)
 155                 ext2fs_free_mem(&inode_buf);
 156         if (block_buf)
 157                 ext2fs_free_mem(&block_buf);
 158         return retval;
 159 }
 160
 161 static errcode_t mark_uninit_bg_group_blocks(ext2_filsys fs)
 162 {
 163         dgrp_t                  i;
 164         blk64_t                 blk;
 165         ext2fs_block_bitmap     bmap = fs->block_map;
 166
 167         for (i = 0; i < fs->group_desc_count; i++) {
 168                 if (!ext2fs_bg_flags_test(fs, i, EXT2_BG_BLOCK_UNINIT))
 169                         continue;
 170
 171                 ext2fs_reserve_super_and_bgd(fs, i, bmap);
 172
 173                 /*
 174                  * Mark the blocks used for the inode table
 175                  */
 176                 blk = ext2fs_inode_table_loc(fs, i);
 177                 if (blk)
 178                         ext2fs_mark_block_bitmap_range2(bmap, blk,
 179                                                 fs->inode_blocks_per_group);
 180
 181                 /*
 182                  * Mark block used for the block bitmap
 183                  */
 184                 blk = ext2fs_block_bitmap_loc(fs, i);
 185                 if (blk)
 186                         ext2fs_mark_block_bitmap2(bmap, blk);
 187
 188                 /*
 189                  * Mark block used for the inode bitmap
 190                  */
 191                 blk = ext2fs_inode_bitmap_loc(fs, i);
 192                 if (blk)
 193                         ext2fs_mark_block_bitmap2(bmap, blk);
 194         }
 195         return 0;
 196 }
 197
 198 static int bitmap_tail_verify(unsigned char *bitmap, int first, int last)
 199 {
 200         int i;
 201
 202         for (i = first; i <= last; i++)
 203                 if (bitmap[i] != 0xff)
 204                         return 0;
 205         return 1;
 206 }
 207
 208 static errcode_t read_bitmaps(ext2_filsys fs, int do_inode, int do_block)
 209 {
 210         dgrp_t i;
 211         char *block_bitmap = 0, *inode_bitmap = 0;
 212         char *buf;
 213         errcode_t retval;
 214         int block_nbytes = EXT2_CLUSTERS_PER_GROUP(fs->super) / 8;
 215         int inode_nbytes = EXT2_INODES_PER_GROUP(fs->super) / 8;
 216         int tail_flags = 0;
 217         int csum_flag;
 218         unsigned int    cnt;
 219         blk64_t blk;
 220         blk64_t blk_itr = EXT2FS_B2C(fs, fs->super->s_first_data_block);
 221         blk64_t   blk_cnt;
 222         ext2_ino_t ino_itr = 1;
 223         ext2_ino_t ino_cnt;
 224
 225         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 226
 227         if ((block_nbytes > (int) fs->blocksize) ||
 228             (inode_nbytes > (int) fs->blocksize))
 229                 return EXT2_ET_CORRUPT_SUPERBLOCK;
 230
 231         fs->write_bitmaps = ext2fs_write_bitmaps;
 232
 233         csum_flag = ext2fs_has_group_desc_csum(fs);
 234
 235         retval = ext2fs_get_mem(strlen(fs->device_name) + 80, &buf);
 236         if (retval)
 237                 return retval;
 238         if (do_block) {
 239                 if (fs->block_map)
 240                         ext2fs_free_block_bitmap(fs->block_map);
 241                 strcpy(buf, "block bitmap for ");
 242                 strcat(buf, fs->device_name);
 243                 retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map);
 244                 if (retval)
 245                         goto cleanup;
 246                 retval = io_channel_alloc_buf(fs->io, 0, &block_bitmap);
 247                 if (retval)
 248                         goto cleanup;
 249         } else
 250                 block_nbytes = 0;
 251         if (do_inode) {
 252                 if (fs->inode_map)
 253                         ext2fs_free_inode_bitmap(fs->inode_map);
 254                 strcpy(buf, "inode bitmap for ");
 255                 strcat(buf, fs->device_name);
 256                 retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map);
 257                 if (retval)
 258                         goto cleanup;
 259                 retval = io_channel_alloc_buf(fs->io, 0, &inode_bitmap);
 260                 if (retval)
 261                         goto cleanup;
 262         } else
 263                 inode_nbytes = 0;
 264         ext2fs_free_mem(&buf);
 265
 266         if (fs->flags & EXT2_FLAG_IMAGE_FILE) {
 267                 blk = (ext2fs_le32_to_cpu(fs->image_header->offset_inodemap) / fs->blocksize);
 268                 ino_cnt = fs->super->s_inodes_count;
 269                 while (inode_bitmap && ino_cnt > 0) {
 270                         retval = io_channel_read_blk64(fs->image_io, blk++,
 271                                                      1, inode_bitmap);
 272                         if (retval)
 273                                 goto cleanup;
 274                         cnt = fs->blocksize << 3;
 275                         if (cnt > ino_cnt)
 276                                 cnt = ino_cnt;
 277                         retval = ext2fs_set_inode_bitmap_range2(fs->inode_map,
 278                                                ino_itr, cnt, inode_bitmap);
 279                         if (retval)
 280                                 goto cleanup;
 281                         ino_itr += cnt;
 282                         ino_cnt -= cnt;
 283                 }
 284                 blk = (ext2fs_le32_to_cpu(fs->image_header->offset_blockmap) /
 285                        fs->blocksize);
 286                 blk_cnt = EXT2_GROUPS_TO_CLUSTERS(fs->super,
 287                                                   fs->group_desc_count);
 288                 while (block_bitmap && blk_cnt > 0) {
 289                         retval = io_channel_read_blk64(fs->image_io, blk++,
 290                                                      1, block_bitmap);
 291                         if (retval)
 292                                 goto cleanup;
 293                         cnt = fs->blocksize << 3;
 294                         if (cnt > blk_cnt)
 295                                 cnt = blk_cnt;
 296                         retval = ext2fs_set_block_bitmap_range2(fs->block_map,
 297                                        blk_itr, cnt, block_bitmap);
 298                         if (retval)
 299                                 goto cleanup;
 300                         blk_itr += cnt;
 301                         blk_cnt -= cnt;
 302                 }
 303                 goto success_cleanup;
 304         }
 305
 306         for (i = 0; i < fs->group_desc_count; i++) {
 307                 if (block_bitmap) {
 308                         blk = ext2fs_block_bitmap_loc(fs, i);
 309                         if (csum_flag &&
 310                             ext2fs_bg_flags_test(fs, i, EXT2_BG_BLOCK_UNINIT) &&
 311                             ext2fs_group_desc_csum_verify(fs, i))
 312                                 blk = 0;
 313                         if (blk) {
 314                                 retval = io_channel_read_blk64(fs->io, blk,
 315                                                                1, block_bitmap);
 316                                 if (retval) {
 317                                         retval = EXT2_ET_BLOCK_BITMAP_READ;
 318                                         goto cleanup;
 319                                 }
 320                                 /* verify block bitmap checksum */
 321                                 if (!(fs->flags &
 322                                       EXT2_FLAG_IGNORE_CSUM_ERRORS) &&
 323                                     !ext2fs_block_bitmap_csum_verify(fs, i,
 324                                                 block_bitmap, block_nbytes)) {
 325                                         retval =
 326                                         EXT2_ET_BLOCK_BITMAP_CSUM_INVALID;
 327                                         goto cleanup;
 328                                 }
 329                                 if (!bitmap_tail_verify((unsigned char *) block_bitmap,
 330                                                         block_nbytes, fs->blocksize - 1))
 331                                         tail_flags |= EXT2_FLAG_BBITMAP_TAIL_PROBLEM;
 332                         } else
 333                                 memset(block_bitmap, 0, block_nbytes);
 334                         cnt = block_nbytes << 3;
 335                         retval = ext2fs_set_block_bitmap_range2(fs->block_map,
 336                                                blk_itr, cnt, block_bitmap);
 337                         if (retval)
 338                                 goto cleanup;
 339                         blk_itr += block_nbytes << 3;
 340                 }
 341                 if (inode_bitmap) {
 342                         blk = ext2fs_inode_bitmap_loc(fs, i);
 343                         if (csum_flag &&
 344                             ext2fs_bg_flags_test(fs, i, EXT2_BG_INODE_UNINIT) &&
 345                             ext2fs_group_desc_csum_verify(fs, i))
 346                                 blk = 0;
 347                         if (blk) {
 348                                 retval = io_channel_read_blk64(fs->io, blk,
 349                                                                1, inode_bitmap);
 350                                 if (retval) {
 351                                         retval = EXT2_ET_INODE_BITMAP_READ;
 352                                         goto cleanup;
 353                                 }
 354
 355                                 /* verify inode bitmap checksum */
 356                                 if (!(fs->flags &
 357                                       EXT2_FLAG_IGNORE_CSUM_ERRORS) &&
 358                                     !ext2fs_inode_bitmap_csum_verify(fs, i,
 359                                                 inode_bitmap, inode_nbytes)) {
 360                                         retval =
 361                                         EXT2_ET_INODE_BITMAP_CSUM_INVALID;
 362                                         goto cleanup;
 363                                 }
 364                                 if (!bitmap_tail_verify((unsigned char *) inode_bitmap,
 365                                                         inode_nbytes, fs->blocksize - 1))
 366                                         tail_flags |= EXT2_FLAG_IBITMAP_TAIL_PROBLEM;
 367                         } else
 368                                 memset(inode_bitmap, 0, inode_nbytes);
 369                         cnt = inode_nbytes << 3;
 370                         retval = ext2fs_set_inode_bitmap_range2(fs->inode_map,
 371                                                ino_itr, cnt, inode_bitmap);
 372                         if (retval)
 373                                 goto cleanup;
 374                         ino_itr += inode_nbytes << 3;
 375                 }
 376         }
 377
 378         /* Mark group blocks for any BLOCK_UNINIT groups */
 379         if (do_block) {
 380                 retval = mark_uninit_bg_group_blocks(fs);
 381                 if (retval)
 382                         goto cleanup;
 383         }
 384
 385 success_cleanup:
 386         if (inode_bitmap) {
 387                 ext2fs_free_mem(&inode_bitmap);
 388                 fs->flags &= ~EXT2_FLAG_IBITMAP_TAIL_PROBLEM;
 389         }
 390         if (block_bitmap) {
 391                 ext2fs_free_mem(&block_bitmap);
 392                 fs->flags &= ~EXT2_FLAG_BBITMAP_TAIL_PROBLEM;
 393         }
 394         fs->flags |= tail_flags;
 395         return 0;
 396
 397 cleanup:
 398         if (do_block) {
 399                 ext2fs_free_mem(&fs->block_map);
 400                 fs->block_map = 0;
 401         }
 402         if (do_inode) {
 403                 ext2fs_free_mem(&fs->inode_map);
 404                 fs->inode_map = 0;
 405         }
 406         if (inode_bitmap)
 407                 ext2fs_free_mem(&inode_bitmap);
 408         if (block_bitmap)
 409                 ext2fs_free_mem(&block_bitmap);
 410         if (buf)
 411                 ext2fs_free_mem(&buf);
 412         return retval;
 413 }
 414
 415 errcode_t ext2fs_read_inode_bitmap(ext2_filsys fs)
 416 {
 417         return read_bitmaps(fs, 1, 0);
 418 }
 419
 420 errcode_t ext2fs_read_block_bitmap(ext2_filsys fs)
 421 {
 422         return read_bitmaps(fs, 0, 1);
 423 }
 424
 425 errcode_t ext2fs_write_inode_bitmap(ext2_filsys fs)
 426 {
 427         return write_bitmaps(fs, 1, 0);
 428 }
 429
 430 errcode_t ext2fs_write_block_bitmap (ext2_filsys fs)
 431 {
 432         return write_bitmaps(fs, 0, 1);
 433 }
 434
 435 errcode_t ext2fs_read_bitmaps(ext2_filsys fs)
 436 {
 437         if (fs->inode_map && fs->block_map)
 438                 return 0;
 439
 440         return read_bitmaps(fs, !fs->inode_map, !fs->block_map);
 441 }
 442
 443 errcode_t ext2fs_write_bitmaps(ext2_filsys fs)
 444 {
 445         int do_inode = fs->inode_map && ext2fs_test_ib_dirty(fs);
 446         int do_block = fs->block_map && ext2fs_test_bb_dirty(fs);
 447
 448         if (!do_inode && !do_block)
 449                 return 0;
 450
 451         return write_bitmaps(fs, do_inode, do_block);
 452 }