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 = 0;
  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         if (EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
  50                                        EXT4_FEATURE_RO_COMPAT_GDT_CSUM))
  51                 csum_flag = 1;
  52
  53         inode_nbytes = block_nbytes = 0;
  54         if (do_block) {
  55                 block_nbytes = EXT2_CLUSTERS_PER_GROUP(fs->super) / 8;
  56                 retval = ext2fs_get_memalign(fs->blocksize, fs->blocksize,
  57                                              &block_buf);
  58                 if (retval)
  59                         goto errout;
  60                 memset(block_buf, 0xff, fs->blocksize);
  61         }
  62         if (do_inode) {
  63                 inode_nbytes = (size_t)
  64                         ((EXT2_INODES_PER_GROUP(fs->super)+7) / 8);
  65                 retval = ext2fs_get_memalign(fs->blocksize, fs->blocksize,
  66                                              &inode_buf);
  67                 if (retval)
  68                         goto errout;
  69                 memset(inode_buf, 0xff, fs->blocksize);
  70         }
  71
  72         for (i = 0; i < fs->group_desc_count; i++) {
  73                 if (!do_block)
  74                         goto skip_block_bitmap;
  75
  76                 if (csum_flag && ext2fs_bg_flags_test(fs, i, EXT2_BG_BLOCK_UNINIT)
  77                     )
  78                         goto skip_this_block_bitmap;
  79
  80                 retval = ext2fs_get_block_bitmap_range2(fs->block_map,
  81                                 blk_itr, block_nbytes << 3, block_buf);
  82                 if (retval)
  83                         goto errout;
  84
  85                 if (i == fs->group_desc_count - 1) {
  86                         /* Force bitmap padding for the last group */
  87                         nbits = EXT2FS_NUM_B2C(fs,
  88                                 ((ext2fs_blocks_count(fs->super)
  89                                   - (__u64) fs->super->s_first_data_block)
  90                                  % (__u64) EXT2_BLOCKS_PER_GROUP(fs->super)));
  91                         if (nbits)
  92                                 for (j = nbits; j < fs->blocksize * 8; j++)
  93                                         ext2fs_set_bit(j, block_buf);
  94                 }
  95                 blk = ext2fs_block_bitmap_loc(fs, i);
  96                 if (blk) {
  97                         retval = io_channel_write_blk64(fs->io, blk, 1,
  98                                                         block_buf);
  99                         if (retval) {
 100                                 retval = EXT2_ET_BLOCK_BITMAP_WRITE;
 101                                 goto errout;
 102                         }
 103                 }
 104         skip_this_block_bitmap:
 105                 blk_itr += block_nbytes << 3;
 106         skip_block_bitmap:
 107
 108                 if (!do_inode)
 109                         continue;
 110
 111                 if (csum_flag && ext2fs_bg_flags_test(fs, i, EXT2_BG_INODE_UNINIT)
 112                     )
 113                         goto skip_this_inode_bitmap;
 114
 115                 retval = ext2fs_get_inode_bitmap_range2(fs->inode_map,
 116                                 ino_itr, inode_nbytes << 3, inode_buf);
 117                 if (retval)
 118                         goto errout;
 119
 120                 blk = ext2fs_inode_bitmap_loc(fs, i);
 121                 if (blk) {
 122                         retval = io_channel_write_blk64(fs->io, blk, 1,
 123                                                       inode_buf);
 124                         if (retval) {
 125                                 retval = EXT2_ET_INODE_BITMAP_WRITE;
 126                                 goto errout;
 127                         }
 128                 }
 129         skip_this_inode_bitmap:
 130                 ino_itr += inode_nbytes << 3;
 131
 132         }
 133         if (do_block) {
 134                 fs->flags &= ~EXT2_FLAG_BB_DIRTY;
 135                 ext2fs_free_mem(&block_buf);
 136         }
 137         if (do_inode) {
 138                 fs->flags &= ~EXT2_FLAG_IB_DIRTY;
 139                 ext2fs_free_mem(&inode_buf);
 140         }
 141         return 0;
 142 errout:
 143         if (inode_buf)
 144                 ext2fs_free_mem(&inode_buf);
 145         if (block_buf)
 146                 ext2fs_free_mem(&block_buf);
 147         return retval;
 148 }
 149
 150 static errcode_t read_bitmaps(ext2_filsys fs, int do_inode, int do_block)
 151 {
 152         dgrp_t i;
 153         char *block_bitmap = 0, *inode_bitmap = 0;
 154         char *buf;
 155         errcode_t retval;
 156         int block_nbytes = EXT2_CLUSTERS_PER_GROUP(fs->super) / 8;
 157         int inode_nbytes = EXT2_INODES_PER_GROUP(fs->super) / 8;
 158         int csum_flag = 0;
 159         int do_image = fs->flags & EXT2_FLAG_IMAGE_FILE;
 160         unsigned int    cnt;
 161         blk64_t blk;
 162         blk64_t blk_itr = EXT2FS_B2C(fs, fs->super->s_first_data_block);
 163         blk64_t   blk_cnt;
 164         ext2_ino_t ino_itr = 1;
 165         ext2_ino_t ino_cnt;
 166
 167         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 168
 169         if ((block_nbytes > fs->blocksize) || (inode_nbytes > fs->blocksize))
 170                 return EXT2_ET_CORRUPT_SUPERBLOCK;
 171
 172         fs->write_bitmaps = ext2fs_write_bitmaps;
 173
 174         if (EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
 175                                        EXT4_FEATURE_RO_COMPAT_GDT_CSUM))
 176                 csum_flag = 1;
 177
 178         retval = ext2fs_get_mem(strlen(fs->device_name) + 80, &buf);
 179         if (retval)
 180                 return retval;
 181         if (do_block) {
 182                 if (fs->block_map)
 183                         ext2fs_free_block_bitmap(fs->block_map);
 184                 strcpy(buf, "block bitmap for ");
 185                 strcat(buf, fs->device_name);
 186                 retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map);
 187                 if (retval)
 188                         goto cleanup;
 189                 if (do_image)
 190                         retval = ext2fs_get_mem(fs->blocksize, &block_bitmap);
 191                 else
 192                         retval = ext2fs_get_memalign(fs->blocksize,
 193                                                      fs->blocksize,
 194                                                      &block_bitmap);
 195
 196                 if (retval)
 197                         goto cleanup;
 198         } else
 199                 block_nbytes = 0;
 200         if (do_inode) {
 201                 if (fs->inode_map)
 202                         ext2fs_free_inode_bitmap(fs->inode_map);
 203                 strcpy(buf, "inode bitmap for ");
 204                 strcat(buf, fs->device_name);
 205                 retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map);
 206                 if (retval)
 207                         goto cleanup;
 208                 retval = ext2fs_get_mem(fs->blocksize, &inode_bitmap);
 209                 if (retval)
 210                         goto cleanup;
 211         } else
 212                 inode_nbytes = 0;
 213         ext2fs_free_mem(&buf);
 214
 215         if (fs->flags & EXT2_FLAG_IMAGE_FILE) {
 216                 blk = (fs->image_header->offset_inodemap / fs->blocksize);
 217                 ino_cnt = fs->super->s_inodes_count;
 218                 while (inode_nbytes > 0) {
 219                         retval = io_channel_read_blk64(fs->image_io, blk++,
 220                                                      1, inode_bitmap);
 221                         if (retval)
 222                                 goto cleanup;
 223                         cnt = fs->blocksize << 3;
 224                         if (cnt > ino_cnt)
 225                                 cnt = ino_cnt;
 226                         retval = ext2fs_set_inode_bitmap_range2(fs->inode_map,
 227                                                ino_itr, cnt, inode_bitmap);
 228                         if (retval)
 229                                 goto cleanup;
 230                         ino_itr += fs->blocksize << 3;
 231                         ino_cnt -= fs->blocksize << 3;
 232                         inode_nbytes -= fs->blocksize;
 233                 }
 234                 blk = (fs->image_header->offset_blockmap /
 235                        fs->blocksize);
 236                 blk_cnt = (blk64_t)EXT2_CLUSTERS_PER_GROUP(fs->super) *
 237                         fs->group_desc_count;
 238                 while (block_nbytes > 0) {
 239                         retval = io_channel_read_blk64(fs->image_io, blk++,
 240                                                      1, block_bitmap);
 241                         if (retval)
 242                                 goto cleanup;
 243                         cnt = fs->blocksize << 3;
 244                         if (cnt > blk_cnt)
 245                                 cnt = blk_cnt;
 246                         retval = ext2fs_set_block_bitmap_range2(fs->block_map,
 247                                        blk_itr, cnt, block_bitmap);
 248                         if (retval)
 249                                 goto cleanup;
 250                         blk_itr += fs->blocksize << 3;
 251                         blk_cnt -= fs->blocksize << 3;
 252                         block_nbytes -= fs->blocksize;
 253                 }
 254                 goto success_cleanup;
 255         }
 256
 257         for (i = 0; i < fs->group_desc_count; i++) {
 258                 if (block_bitmap) {
 259                         blk = ext2fs_block_bitmap_loc(fs, i);
 260                         if (csum_flag &&
 261                             ext2fs_bg_flags_test(fs, i, EXT2_BG_BLOCK_UNINIT) &&
 262                             ext2fs_group_desc_csum_verify(fs, i))
 263                                 blk = 0;
 264                         if (blk) {
 265                                 retval = io_channel_read_blk64(fs->io, blk,
 266                                                                1, block_bitmap);
 267                                 if (retval) {
 268                                         retval = EXT2_ET_BLOCK_BITMAP_READ;
 269                                         goto cleanup;
 270                                 }
 271                         } else
 272                                 memset(block_bitmap, 0, block_nbytes);
 273                         cnt = block_nbytes << 3;
 274                         retval = ext2fs_set_block_bitmap_range2(fs->block_map,
 275                                                blk_itr, cnt, block_bitmap);
 276                         if (retval)
 277                                 goto cleanup;
 278                         blk_itr += block_nbytes << 3;
 279                 }
 280                 if (inode_bitmap) {
 281                         blk = ext2fs_inode_bitmap_loc(fs, i);
 282                         if (csum_flag &&
 283                             ext2fs_bg_flags_test(fs, i, EXT2_BG_INODE_UNINIT) &&
 284                             ext2fs_group_desc_csum_verify(fs, i))
 285                                 blk = 0;
 286                         if (blk) {
 287                                 retval = io_channel_read_blk64(fs->io, blk,
 288                                                                1, inode_bitmap);
 289                                 if (retval) {
 290                                         retval = EXT2_ET_INODE_BITMAP_READ;
 291                                         goto cleanup;
 292                                 }
 293                         } else
 294                                 memset(inode_bitmap, 0, inode_nbytes);
 295                         cnt = inode_nbytes << 3;
 296                         retval = ext2fs_set_inode_bitmap_range2(fs->inode_map,
 297                                                ino_itr, cnt, inode_bitmap);
 298                         if (retval)
 299                                 goto cleanup;
 300                         ino_itr += inode_nbytes << 3;
 301                 }
 302         }
 303 success_cleanup:
 304         if (inode_bitmap)
 305                 ext2fs_free_mem(&inode_bitmap);
 306         if (block_bitmap)
 307                 ext2fs_free_mem(&block_bitmap);
 308         return 0;
 309
 310 cleanup:
 311         if (do_block) {
 312                 ext2fs_free_mem(&fs->block_map);
 313                 fs->block_map = 0;
 314         }
 315         if (do_inode) {
 316                 ext2fs_free_mem(&fs->inode_map);
 317                 fs->inode_map = 0;
 318         }
 319         if (inode_bitmap)
 320                 ext2fs_free_mem(&inode_bitmap);
 321         if (block_bitmap)
 322                 ext2fs_free_mem(&block_bitmap);
 323         if (buf)
 324                 ext2fs_free_mem(&buf);
 325         return retval;
 326 }
 327
 328 errcode_t ext2fs_read_inode_bitmap(ext2_filsys fs)
 329 {
 330         return read_bitmaps(fs, 1, 0);
 331 }
 332
 333 errcode_t ext2fs_read_block_bitmap(ext2_filsys fs)
 334 {
 335         return read_bitmaps(fs, 0, 1);
 336 }
 337
 338 errcode_t ext2fs_write_inode_bitmap(ext2_filsys fs)
 339 {
 340         return write_bitmaps(fs, 1, 0);
 341 }
 342
 343 errcode_t ext2fs_write_block_bitmap (ext2_filsys fs)
 344 {
 345         return write_bitmaps(fs, 0, 1);
 346 }
 347
 348 errcode_t ext2fs_read_bitmaps(ext2_filsys fs)
 349 {
 350         if (fs->inode_map && fs->block_map)
 351                 return 0;
 352
 353         return read_bitmaps(fs, !fs->inode_map, !fs->block_map);
 354 }
 355
 356 errcode_t ext2fs_write_bitmaps(ext2_filsys fs)
 357 {
 358         int do_inode = fs->inode_map && ext2fs_test_ib_dirty(fs);
 359         int do_block = fs->block_map && ext2fs_test_bb_dirty(fs);
 360
 361         if (!do_inode && !do_block)
 362                 return 0;
 363
 364         return write_bitmaps(fs, do_inode, do_block);
 365 }