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
  98                 blk = ext2fs_block_bitmap_loc(fs, i);
  99                 if (blk) {
 100                         retval = io_channel_write_blk64(fs->io, blk, 1,
 101                                                         block_buf);
 102                         if (retval) {
 103                                 retval = EXT2_ET_BLOCK_BITMAP_WRITE;
 104                                 goto errout;
 105                         }
 106                 }
 107         skip_this_block_bitmap:
 108                 blk_itr += block_nbytes << 3;
 109         skip_block_bitmap:
 110
 111                 if (!do_inode)
 112                         continue;
 113
 114                 if (csum_flag && ext2fs_bg_flags_test(fs, i, EXT2_BG_INODE_UNINIT)
 115                     )
 116                         goto skip_this_inode_bitmap;
 117
 118                 retval = ext2fs_get_inode_bitmap_range2(fs->inode_map,
 119                                 ino_itr, inode_nbytes << 3, inode_buf);
 120                 if (retval)
 121                         goto errout;
 122
 123                 retval = ext2fs_inode_bitmap_csum_set(fs, i, inode_buf,
 124                                                       inode_nbytes);
 125                 if (retval)
 126                         goto errout;
 127                 ext2fs_group_desc_csum_set(fs, i);
 128
 129                 blk = ext2fs_inode_bitmap_loc(fs, i);
 130                 if (blk) {
 131                         retval = io_channel_write_blk64(fs->io, blk, 1,
 132                                                       inode_buf);
 133                         if (retval) {
 134                                 retval = EXT2_ET_INODE_BITMAP_WRITE;
 135                                 goto errout;
 136                         }
 137                 }
 138         skip_this_inode_bitmap:
 139                 ino_itr += inode_nbytes << 3;
 140
 141         }
 142         if (do_block) {
 143                 fs->flags &= ~EXT2_FLAG_BB_DIRTY;
 144                 ext2fs_free_mem(&block_buf);
 145         }
 146         if (do_inode) {
 147                 fs->flags &= ~EXT2_FLAG_IB_DIRTY;
 148                 ext2fs_free_mem(&inode_buf);
 149         }
 150         return 0;
 151 errout:
 152         if (inode_buf)
 153                 ext2fs_free_mem(&inode_buf);
 154         if (block_buf)
 155                 ext2fs_free_mem(&block_buf);
 156         return retval;
 157 }
 158
 159 static errcode_t mark_uninit_bg_group_blocks(ext2_filsys fs)
 160 {
 161         dgrp_t                  i;
 162         blk64_t                 blk;
 163         ext2fs_block_bitmap     bmap = fs->block_map;
 164
 165         for (i = 0; i < fs->group_desc_count; i++) {
 166                 if (!ext2fs_bg_flags_test(fs, i, EXT2_BG_BLOCK_UNINIT))
 167                         continue;
 168
 169                 ext2fs_reserve_super_and_bgd(fs, i, bmap);
 170
 171                 /*
 172                  * Mark the blocks used for the inode table
 173                  */
 174                 blk = ext2fs_inode_table_loc(fs, i);
 175                 if (blk)
 176                         ext2fs_mark_block_bitmap_range2(bmap, blk,
 177                                                 fs->inode_blocks_per_group);
 178
 179                 /*
 180                  * Mark block used for the block bitmap
 181                  */
 182                 blk = ext2fs_block_bitmap_loc(fs, i);
 183                 if (blk)
 184                         ext2fs_mark_block_bitmap2(bmap, blk);
 185
 186                 /*
 187                  * Mark block used for the inode bitmap
 188                  */
 189                 blk = ext2fs_inode_bitmap_loc(fs, i);
 190                 if (blk)
 191                         ext2fs_mark_block_bitmap2(bmap, blk);
 192         }
 193         return 0;
 194 }
 195
 196 static errcode_t read_bitmaps(ext2_filsys fs, int do_inode, int do_block)
 197 {
 198         dgrp_t i;
 199         char *block_bitmap = 0, *inode_bitmap = 0;
 200         char *buf;
 201         errcode_t retval;
 202         int block_nbytes = EXT2_CLUSTERS_PER_GROUP(fs->super) / 8;
 203         int inode_nbytes = EXT2_INODES_PER_GROUP(fs->super) / 8;
 204         int csum_flag;
 205         unsigned int    cnt;
 206         blk64_t blk;
 207         blk64_t blk_itr = EXT2FS_B2C(fs, fs->super->s_first_data_block);
 208         blk64_t   blk_cnt;
 209         ext2_ino_t ino_itr = 1;
 210         ext2_ino_t ino_cnt;
 211
 212         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 213
 214         if ((block_nbytes > (int) fs->blocksize) ||
 215             (inode_nbytes > (int) fs->blocksize))
 216                 return EXT2_ET_CORRUPT_SUPERBLOCK;
 217
 218         fs->write_bitmaps = ext2fs_write_bitmaps;
 219
 220         csum_flag = ext2fs_has_group_desc_csum(fs);
 221
 222         retval = ext2fs_get_mem(strlen(fs->device_name) + 80, &buf);
 223         if (retval)
 224                 return retval;
 225         if (do_block) {
 226                 if (fs->block_map)
 227                         ext2fs_free_block_bitmap(fs->block_map);
 228                 strcpy(buf, "block bitmap for ");
 229                 strcat(buf, fs->device_name);
 230                 retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map);
 231                 if (retval)
 232                         goto cleanup;
 233                 retval = io_channel_alloc_buf(fs->io, 0, &block_bitmap);
 234                 if (retval)
 235                         goto cleanup;
 236         } else
 237                 block_nbytes = 0;
 238         if (do_inode) {
 239                 if (fs->inode_map)
 240                         ext2fs_free_inode_bitmap(fs->inode_map);
 241                 strcpy(buf, "inode bitmap for ");
 242                 strcat(buf, fs->device_name);
 243                 retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map);
 244                 if (retval)
 245                         goto cleanup;
 246                 retval = io_channel_alloc_buf(fs->io, 0, &inode_bitmap);
 247                 if (retval)
 248                         goto cleanup;
 249         } else
 250                 inode_nbytes = 0;
 251         ext2fs_free_mem(&buf);
 252
 253         if (fs->flags & EXT2_FLAG_IMAGE_FILE) {
 254                 blk = (fs->image_header->offset_inodemap / fs->blocksize);
 255                 ino_cnt = fs->super->s_inodes_count;
 256                 while (inode_nbytes > 0) {
 257                         retval = io_channel_read_blk64(fs->image_io, blk++,
 258                                                      1, inode_bitmap);
 259                         if (retval)
 260                                 goto cleanup;
 261                         cnt = fs->blocksize << 3;
 262                         if (cnt > ino_cnt)
 263                                 cnt = ino_cnt;
 264                         retval = ext2fs_set_inode_bitmap_range2(fs->inode_map,
 265                                                ino_itr, cnt, inode_bitmap);
 266                         if (retval)
 267                                 goto cleanup;
 268                         ino_itr += fs->blocksize << 3;
 269                         ino_cnt -= fs->blocksize << 3;
 270                         inode_nbytes -= fs->blocksize;
 271                 }
 272                 blk = (fs->image_header->offset_blockmap /
 273                        fs->blocksize);
 274                 blk_cnt = (blk64_t)EXT2_CLUSTERS_PER_GROUP(fs->super) *
 275                         fs->group_desc_count;
 276                 while (block_nbytes > 0) {
 277                         retval = io_channel_read_blk64(fs->image_io, blk++,
 278                                                      1, block_bitmap);
 279                         if (retval)
 280                                 goto cleanup;
 281                         cnt = fs->blocksize << 3;
 282                         if (cnt > blk_cnt)
 283                                 cnt = blk_cnt;
 284                         retval = ext2fs_set_block_bitmap_range2(fs->block_map,
 285                                        blk_itr, cnt, block_bitmap);
 286                         if (retval)
 287                                 goto cleanup;
 288                         blk_itr += fs->blocksize << 3;
 289                         blk_cnt -= fs->blocksize << 3;
 290                         block_nbytes -= fs->blocksize;
 291                 }
 292                 goto success_cleanup;
 293         }
 294
 295         for (i = 0; i < fs->group_desc_count; i++) {
 296                 if (block_bitmap) {
 297                         blk = ext2fs_block_bitmap_loc(fs, i);
 298                         if (csum_flag &&
 299                             ext2fs_bg_flags_test(fs, i, EXT2_BG_BLOCK_UNINIT) &&
 300                             ext2fs_group_desc_csum_verify(fs, i))
 301                                 blk = 0;
 302                         if (blk) {
 303                                 retval = io_channel_read_blk64(fs->io, blk,
 304                                                                1, block_bitmap);
 305                                 if (retval) {
 306                                         retval = EXT2_ET_BLOCK_BITMAP_READ;
 307                                         goto cleanup;
 308                                 }
 309                                 /* verify block bitmap checksum */
 310                                 if (!(fs->flags &
 311                                       EXT2_FLAG_IGNORE_CSUM_ERRORS) &&
 312                                     !ext2fs_block_bitmap_csum_verify(fs, i,
 313                                                 block_bitmap, block_nbytes)) {
 314                                         retval =
 315                                         EXT2_ET_BLOCK_BITMAP_CSUM_INVALID;
 316                                         goto cleanup;
 317                                 }
 318                         } else
 319                                 memset(block_bitmap, 0, block_nbytes);
 320                         cnt = block_nbytes << 3;
 321                         retval = ext2fs_set_block_bitmap_range2(fs->block_map,
 322                                                blk_itr, cnt, block_bitmap);
 323                         if (retval)
 324                                 goto cleanup;
 325                         blk_itr += block_nbytes << 3;
 326                 }
 327                 if (inode_bitmap) {
 328                         blk = ext2fs_inode_bitmap_loc(fs, i);
 329                         if (csum_flag &&
 330                             ext2fs_bg_flags_test(fs, i, EXT2_BG_INODE_UNINIT) &&
 331                             ext2fs_group_desc_csum_verify(fs, i))
 332                                 blk = 0;
 333                         if (blk) {
 334                                 retval = io_channel_read_blk64(fs->io, blk,
 335                                                                1, inode_bitmap);
 336                                 if (retval) {
 337                                         retval = EXT2_ET_INODE_BITMAP_READ;
 338                                         goto cleanup;
 339                                 }
 340
 341                                 /* verify inode bitmap checksum */
 342                                 if (!(fs->flags &
 343                                       EXT2_FLAG_IGNORE_CSUM_ERRORS) &&
 344                                     !ext2fs_inode_bitmap_csum_verify(fs, i,
 345                                                 inode_bitmap, inode_nbytes)) {
 346                                         retval =
 347                                         EXT2_ET_INODE_BITMAP_CSUM_INVALID;
 348                                         goto cleanup;
 349                                 }
 350                         } else
 351                                 memset(inode_bitmap, 0, inode_nbytes);
 352                         cnt = inode_nbytes << 3;
 353                         retval = ext2fs_set_inode_bitmap_range2(fs->inode_map,
 354                                                ino_itr, cnt, inode_bitmap);
 355                         if (retval)
 356                                 goto cleanup;
 357                         ino_itr += inode_nbytes << 3;
 358                 }
 359         }
 360
 361         /* Mark group blocks for any BLOCK_UNINIT groups */
 362         if (do_block) {
 363                 retval = mark_uninit_bg_group_blocks(fs);
 364                 if (retval)
 365                         goto cleanup;
 366         }
 367
 368 success_cleanup:
 369         if (inode_bitmap)
 370                 ext2fs_free_mem(&inode_bitmap);
 371         if (block_bitmap)
 372                 ext2fs_free_mem(&block_bitmap);
 373         return 0;
 374
 375 cleanup:
 376         if (do_block) {
 377                 ext2fs_free_mem(&fs->block_map);
 378                 fs->block_map = 0;
 379         }
 380         if (do_inode) {
 381                 ext2fs_free_mem(&fs->inode_map);
 382                 fs->inode_map = 0;
 383         }
 384         if (inode_bitmap)
 385                 ext2fs_free_mem(&inode_bitmap);
 386         if (block_bitmap)
 387                 ext2fs_free_mem(&block_bitmap);
 388         if (buf)
 389                 ext2fs_free_mem(&buf);
 390         return retval;
 391 }
 392
 393 errcode_t ext2fs_read_inode_bitmap(ext2_filsys fs)
 394 {
 395         return read_bitmaps(fs, 1, 0);
 396 }
 397
 398 errcode_t ext2fs_read_block_bitmap(ext2_filsys fs)
 399 {
 400         return read_bitmaps(fs, 0, 1);
 401 }
 402
 403 errcode_t ext2fs_write_inode_bitmap(ext2_filsys fs)
 404 {
 405         return write_bitmaps(fs, 1, 0);
 406 }
 407
 408 errcode_t ext2fs_write_block_bitmap (ext2_filsys fs)
 409 {
 410         return write_bitmaps(fs, 0, 1);
 411 }
 412
 413 errcode_t ext2fs_read_bitmaps(ext2_filsys fs)
 414 {
 415         if (fs->inode_map && fs->block_map)
 416                 return 0;
 417
 418         return read_bitmaps(fs, !fs->inode_map, !fs->block_map);
 419 }
 420
 421 errcode_t ext2fs_write_bitmaps(ext2_filsys fs)
 422 {
 423         int do_inode = fs->inode_map && ext2fs_test_ib_dirty(fs);
 424         int do_block = fs->block_map && ext2fs_test_bb_dirty(fs);
 425
 426         if (!do_inode && !do_block)
 427                 return 0;
 428
 429         return write_bitmaps(fs, do_inode, do_block);
 430 }