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 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 #include <fcntl.h>
  18 #include <time.h>
  19 #ifdef HAVE_SYS_STAT_H
  20 #include <sys/stat.h>
  21 #endif
  22 #ifdef HAVE_SYS_TYPES_H
  23 #include <sys/types.h>
  24 #endif
  25
  26 #include "ext2_fs.h"
  27 #include "ext2fs.h"
  28 #include "e2image.h"
  29
  30 static errcode_t write_bitmaps(ext2_filsys fs, int do_inode, int do_block)
  31 {
  32         dgrp_t          i;
  33         unsigned int    j;
  34         int             block_nbytes, inode_nbytes;
  35         unsigned int    nbits;
  36         errcode_t       retval;
  37         char            *block_buf, *inode_buf;
  38         int             csum_flag = 0;
  39         blk_t           blk;
  40         blk64_t         blk_itr = fs->super->s_first_data_block;
  41         ext2_ino_t      ino_itr = 1;
  42
  43         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
  44
  45         if (!(fs->flags & EXT2_FLAG_RW))
  46                 return EXT2_ET_RO_FILSYS;
  47
  48         if (EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
  49                                        EXT4_FEATURE_RO_COMPAT_GDT_CSUM))
  50                 csum_flag = 1;
  51
  52         inode_nbytes = block_nbytes = 0;
  53         if (do_block) {
  54                 block_nbytes = EXT2_BLOCKS_PER_GROUP(fs->super) / 8;
  55                 retval = ext2fs_get_mem(fs->blocksize, &block_buf);
  56                 if (retval)
  57                         return retval;
  58                 memset(block_buf, 0xff, fs->blocksize);
  59         }
  60         if (do_inode) {
  61                 inode_nbytes = (size_t)
  62                         ((EXT2_INODES_PER_GROUP(fs->super)+7) / 8);
  63                 retval = ext2fs_get_mem(fs->blocksize, &inode_buf);
  64                 if (retval)
  65                         return retval;
  66                 memset(inode_buf, 0xff, fs->blocksize);
  67         }
  68
  69         for (i = 0; i < fs->group_desc_count; i++) {
  70                 if (!do_block)
  71                         goto skip_block_bitmap;
  72
  73                 if (csum_flag && ext2fs_bg_flag_test(fs, i, EXT2_BG_BLOCK_UNINIT)
  74                     )
  75                         goto skip_this_block_bitmap;
  76
  77                 retval = ext2fs_get_block_bitmap_range2(fs->block_map,
  78                                 blk_itr, block_nbytes << 3, block_buf);
  79                 if (retval)
  80                         return retval;
  81
  82                 if (i == fs->group_desc_count - 1) {
  83                         /* Force bitmap padding for the last group */
  84                         nbits = ((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                 blk = fs->group_desc[i].bg_block_bitmap;
  92                 if (blk) {
  93                         retval = io_channel_write_blk64(fs->io, blk, 1,
  94                                                         block_buf);
  95                         if (retval)
  96                                 return EXT2_ET_BLOCK_BITMAP_WRITE;
  97                 }
  98         skip_this_block_bitmap:
  99                 blk_itr += block_nbytes << 3;
 100         skip_block_bitmap:
 101
 102                 if (!do_inode)
 103                         continue;
 104
 105                 if (csum_flag && ext2fs_bg_flag_test(fs, i, EXT2_BG_INODE_UNINIT)
 106                     )
 107                         goto skip_this_inode_bitmap;
 108
 109                 retval = ext2fs_get_inode_bitmap_range2(fs->inode_map,
 110                                 ino_itr, inode_nbytes << 3, inode_buf);
 111                 if (retval)
 112                         return retval;
 113
 114                 blk = fs->group_desc[i].bg_inode_bitmap;
 115                 if (blk) {
 116                         retval = io_channel_write_blk64(fs->io, blk, 1,
 117                                                       inode_buf);
 118                         if (retval)
 119                                 return EXT2_ET_INODE_BITMAP_WRITE;
 120                 }
 121         skip_this_inode_bitmap:
 122                 ino_itr += inode_nbytes << 3;
 123
 124         }
 125         if (do_block) {
 126                 fs->flags &= ~EXT2_FLAG_BB_DIRTY;
 127                 ext2fs_free_mem(&block_buf);
 128         }
 129         if (do_inode) {
 130                 fs->flags &= ~EXT2_FLAG_IB_DIRTY;
 131                 ext2fs_free_mem(&inode_buf);
 132         }
 133         return 0;
 134 }
 135
 136 static errcode_t read_bitmaps(ext2_filsys fs, int do_inode, int do_block)
 137 {
 138         dgrp_t i;
 139         char *block_bitmap = 0, *inode_bitmap = 0;
 140         char *buf;
 141         errcode_t retval;
 142         int block_nbytes = EXT2_BLOCKS_PER_GROUP(fs->super) / 8;
 143         int inode_nbytes = EXT2_INODES_PER_GROUP(fs->super) / 8;
 144         int csum_flag = 0;
 145         int do_image = fs->flags & EXT2_FLAG_IMAGE_FILE;
 146         unsigned int    cnt;
 147         blk_t   blk;
 148         blk64_t blk_itr = fs->super->s_first_data_block;
 149         blk_t   blk_cnt;
 150         ext2_ino_t ino_itr = 1;
 151         ext2_ino_t ino_cnt;
 152
 153         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 154
 155         fs->write_bitmaps = ext2fs_write_bitmaps;
 156
 157         if (EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
 158                                        EXT4_FEATURE_RO_COMPAT_GDT_CSUM))
 159                 csum_flag = 1;
 160
 161         retval = ext2fs_get_mem(strlen(fs->device_name) + 80, &buf);
 162         if (retval)
 163                 return retval;
 164         if (do_block) {
 165                 if (fs->block_map)
 166                         ext2fs_free_block_bitmap(fs->block_map);
 167                 strcpy(buf, "block bitmap for ");
 168                 strcat(buf, fs->device_name);
 169                 retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map);
 170                 if (retval)
 171                         goto cleanup;
 172                 retval = ext2fs_get_mem(do_image ? fs->blocksize :
 173                                         (unsigned) block_nbytes, &block_bitmap);
 174                 if (retval)
 175                         goto cleanup;
 176         } else
 177                 block_nbytes = 0;
 178         if (do_inode) {
 179                 if (fs->inode_map)
 180                         ext2fs_free_inode_bitmap(fs->inode_map);
 181                 strcpy(buf, "inode bitmap for ");
 182                 strcat(buf, fs->device_name);
 183                 retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map);
 184                 if (retval)
 185                         goto cleanup;
 186                 retval = ext2fs_get_mem(do_image ? fs->blocksize :
 187                                         (unsigned) inode_nbytes, &inode_bitmap);
 188                 if (retval)
 189                         goto cleanup;
 190         } else
 191                 inode_nbytes = 0;
 192         ext2fs_free_mem(&buf);
 193
 194         if (fs->flags & EXT2_FLAG_IMAGE_FILE) {
 195                 blk = (fs->image_header->offset_inodemap / fs->blocksize);
 196                 ino_cnt = fs->super->s_inodes_count;
 197                 while (inode_nbytes > 0) {
 198                         retval = io_channel_read_blk64(fs->image_io, blk++,
 199                                                      1, inode_bitmap);
 200                         if (retval)
 201                                 goto cleanup;
 202                         cnt = fs->blocksize << 3;
 203                         if (cnt > ino_cnt)
 204                                 cnt = ino_cnt;
 205                         retval = ext2fs_set_inode_bitmap_range2(fs->inode_map,
 206                                                ino_itr, cnt, inode_bitmap);
 207                         if (retval)
 208                                 goto cleanup;
 209                         ino_itr += fs->blocksize << 3;
 210                         ino_cnt -= fs->blocksize << 3;
 211                         inode_nbytes -= fs->blocksize;
 212                 }
 213                 blk = (fs->image_header->offset_blockmap /
 214                        fs->blocksize);
 215                 blk_cnt = (blk64_t)EXT2_BLOCKS_PER_GROUP(fs->super) *
 216                         fs->group_desc_count;
 217                 while (block_nbytes > 0) {
 218                         retval = io_channel_read_blk64(fs->image_io, blk++,
 219                                                      1, block_bitmap);
 220                         if (retval)
 221                                 goto cleanup;
 222                         cnt = fs->blocksize << 3;
 223                         if (cnt > blk_cnt)
 224                                 cnt = blk_cnt;
 225                         retval = ext2fs_set_block_bitmap_range2(fs->block_map,
 226                                        blk_itr, cnt, block_bitmap);
 227                         if (retval)
 228                                 goto cleanup;
 229                         blk_itr += fs->blocksize << 3;
 230                         blk_cnt -= fs->blocksize << 3;
 231                         block_nbytes -= fs->blocksize;
 232                 }
 233                 goto success_cleanup;
 234         }
 235
 236         for (i = 0; i < fs->group_desc_count; i++) {
 237                 if (block_bitmap) {
 238                         blk = fs->group_desc[i].bg_block_bitmap;
 239                         if (csum_flag &&
 240                             ext2fs_bg_flag_test(fs, i, EXT2_BG_BLOCK_UNINIT) &&
 241                             ext2fs_group_desc_csum_verify(fs, i))
 242                                 blk = 0;
 243                         if (blk) {
 244                                 retval = io_channel_read_blk64(fs->io, blk,
 245                                              -block_nbytes, block_bitmap);
 246                                 if (retval) {
 247                                         retval = EXT2_ET_BLOCK_BITMAP_READ;
 248                                         goto cleanup;
 249                                 }
 250                         } else
 251                                 memset(block_bitmap, 0, block_nbytes);
 252                         cnt = block_nbytes << 3;
 253                         retval = ext2fs_set_block_bitmap_range2(fs->block_map,
 254                                                blk_itr, cnt, block_bitmap);
 255                         if (retval)
 256                                 goto cleanup;
 257                         blk_itr += block_nbytes << 3;
 258                 }
 259                 if (inode_bitmap) {
 260                         blk = fs->group_desc[i].bg_inode_bitmap;
 261                         if (csum_flag &&
 262                             ext2fs_bg_flag_test(fs, i, EXT2_BG_INODE_UNINIT) &&
 263                             ext2fs_group_desc_csum_verify(fs, i))
 264                                 blk = 0;
 265                         if (blk) {
 266                                 retval = io_channel_read_blk64(fs->io, blk,
 267                                              -inode_nbytes, inode_bitmap);
 268                                 if (retval) {
 269                                         retval = EXT2_ET_INODE_BITMAP_READ;
 270                                         goto cleanup;
 271                                 }
 272                         } else
 273                                 memset(inode_bitmap, 0, inode_nbytes);
 274                         cnt = inode_nbytes << 3;
 275                         retval = ext2fs_set_inode_bitmap_range2(fs->inode_map,
 276                                                ino_itr, cnt, inode_bitmap);
 277                         if (retval)
 278                                 goto cleanup;
 279                         ino_itr += inode_nbytes << 3;
 280                 }
 281         }
 282 success_cleanup:
 283         if (inode_bitmap)
 284                 ext2fs_free_mem(&inode_bitmap);
 285         if (block_bitmap)
 286                 ext2fs_free_mem(&block_bitmap);
 287         return 0;
 288
 289 cleanup:
 290         if (do_block) {
 291                 ext2fs_free_mem(&fs->block_map);
 292                 fs->block_map = 0;
 293         }
 294         if (do_inode) {
 295                 ext2fs_free_mem(&fs->inode_map);
 296                 fs->inode_map = 0;
 297         }
 298         if (inode_bitmap)
 299                 ext2fs_free_mem(&inode_bitmap);
 300         if (block_bitmap)
 301                 ext2fs_free_mem(&block_bitmap);
 302         if (buf)
 303                 ext2fs_free_mem(&buf);
 304         return retval;
 305 }
 306
 307 errcode_t ext2fs_read_inode_bitmap(ext2_filsys fs)
 308 {
 309         return read_bitmaps(fs, 1, 0);
 310 }
 311
 312 errcode_t ext2fs_read_block_bitmap(ext2_filsys fs)
 313 {
 314         return read_bitmaps(fs, 0, 1);
 315 }
 316
 317 errcode_t ext2fs_write_inode_bitmap(ext2_filsys fs)
 318 {
 319         return write_bitmaps(fs, 1, 0);
 320 }
 321
 322 errcode_t ext2fs_write_block_bitmap (ext2_filsys fs)
 323 {
 324         return write_bitmaps(fs, 0, 1);
 325 }
 326
 327 errcode_t ext2fs_read_bitmaps(ext2_filsys fs)
 328 {
 329         if (fs->inode_map && fs->block_map)
 330                 return 0;
 331
 332         return read_bitmaps(fs, !fs->inode_map, !fs->block_map);
 333 }
 334
 335 errcode_t ext2fs_write_bitmaps(ext2_filsys fs)
 336 {
 337         int do_inode = fs->inode_map && ext2fs_test_ib_dirty(fs);
 338         int do_block = fs->block_map && ext2fs_test_bb_dirty(fs);
 339
 340         if (!do_inode && !do_block)
 341                 return 0;
 342
 343         return write_bitmaps(fs, do_inode, do_block);
 344 }