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