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