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             lazy_flag = 0;
  39         blk_t           blk;
  40         blk_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         if (EXT2_HAS_COMPAT_FEATURE(fs->super,
  48                                     EXT2_FEATURE_COMPAT_LAZY_BG))
  49                 lazy_flag = 1;
  50         inode_nbytes = block_nbytes = 0;
  51         if (do_block) {
  52                 block_nbytes = EXT2_BLOCKS_PER_GROUP(fs->super) / 8;
  53                 retval = ext2fs_get_mem(fs->blocksize, &block_buf);
  54                 if (retval)
  55                         return retval;
  56                 memset(block_buf, 0xff, fs->blocksize);
  57         }
  58         if (do_inode) {
  59                 inode_nbytes = (size_t)
  60                         ((EXT2_INODES_PER_GROUP(fs->super)+7) / 8);
  61                 retval = ext2fs_get_mem(fs->blocksize, &inode_buf);
  62                 if (retval)
  63                         return retval;
  64                 memset(inode_buf, 0xff, fs->blocksize);
  65         }
  66
  67         for (i = 0; i < fs->group_desc_count; i++) {
  68                 if (!do_block)
  69                         goto skip_block_bitmap;
  70
  71                 if (lazy_flag && fs->group_desc[i].bg_flags &
  72                     EXT2_BG_BLOCK_UNINIT)
  73                         goto skip_this_block_bitmap;
  74
  75                 retval = ext2fs_get_block_bitmap_range(fs->block_map,
  76                                 blk_itr, block_nbytes << 3, block_buf);
  77                 if (retval)
  78                         return retval;
  79
  80                 if (i == fs->group_desc_count - 1) {
  81                         /* Force bitmap padding for the last group */
  82                         nbits = ((fs->super->s_blocks_count
  83                                   - fs->super->s_first_data_block)
  84                                  % EXT2_BLOCKS_PER_GROUP(fs->super));
  85                         if (nbits)
  86                                 for (j = nbits; j < fs->blocksize * 8; j++)
  87                                         ext2fs_set_bit(j, block_buf);
  88                 }
  89                 blk = fs->group_desc[i].bg_block_bitmap;
  90                 if (blk) {
  91                         retval = io_channel_write_blk(fs->io, blk, 1,
  92                                                       block_buf);
  93                         if (retval)
  94                                 return EXT2_ET_BLOCK_BITMAP_WRITE;
  95                 }
  96         skip_this_block_bitmap:
  97                 blk_itr += block_nbytes << 3;
  98         skip_block_bitmap:
  99
 100                 if (!do_inode)
 101                         continue;
 102
 103                 if (lazy_flag && fs->group_desc[i].bg_flags &
 104                     EXT2_BG_INODE_UNINIT)
 105                         goto skip_this_inode_bitmap;
 106
 107                 retval = ext2fs_get_inode_bitmap_range(fs->inode_map,
 108                                 ino_itr, inode_nbytes << 3, inode_buf);
 109                 if (retval)
 110                         return retval;
 111
 112                 blk = fs->group_desc[i].bg_inode_bitmap;
 113                 if (blk) {
 114                         retval = io_channel_write_blk(fs->io, blk, 1,
 115                                                       inode_buf);
 116                         if (retval)
 117                                 return EXT2_ET_INODE_BITMAP_WRITE;
 118                 }
 119         skip_this_inode_bitmap:
 120                 ino_itr += inode_nbytes << 3;
 121
 122         }
 123         if (do_block) {
 124                 fs->flags &= ~EXT2_FLAG_BB_DIRTY;
 125                 ext2fs_free_mem(&block_buf);
 126         }
 127         if (do_inode) {
 128                 fs->flags &= ~EXT2_FLAG_IB_DIRTY;
 129                 ext2fs_free_mem(&inode_buf);
 130         }
 131         return 0;
 132 }
 133
 134 static errcode_t read_bitmaps(ext2_filsys fs, int do_inode, int do_block)
 135 {
 136         dgrp_t i;
 137         char *block_bitmap = 0, *inode_bitmap = 0;
 138         char *buf;
 139         errcode_t retval;
 140         unsigned int block_nbytes = EXT2_BLOCKS_PER_GROUP(fs->super) / 8;
 141         unsigned inode_nbytes = EXT2_INODES_PER_GROUP(fs->super) / 8;
 142         int lazy_flag = 0;
 143         int do_image = fs->flags & EXT2_FLAG_IMAGE_FILE;
 144         unsigned int    cnt;
 145         blk_t   blk;
 146         blk_t   blk_itr = fs->super->s_first_data_block;
 147         blk_t   blk_cnt;
 148         ext2_ino_t ino_itr = 1;
 149         ext2_ino_t ino_cnt;
 150
 151         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 152
 153         fs->write_bitmaps = ext2fs_write_bitmaps;
 154
 155         if (EXT2_HAS_COMPAT_FEATURE(fs->super,
 156                                     EXT2_FEATURE_COMPAT_LAZY_BG) ||
 157             EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
 158                                        EXT4_FEATURE_RO_COMPAT_GDT_CSUM))
 159                 lazy_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                 sprintf(buf, "block bitmap for %s", fs->device_name);
 168                 retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map);
 169                 if (retval)
 170                         goto cleanup;
 171                 retval = ext2fs_get_mem(do_image ? fs->blocksize :
 172                                         block_nbytes, &block_bitmap);
 173                 if (retval)
 174                         goto cleanup;
 175         } else
 176                 block_nbytes = 0;
 177         if (do_inode) {
 178                 if (fs->inode_map)
 179                         ext2fs_free_inode_bitmap(fs->inode_map);
 180                 sprintf(buf, "inode bitmap for %s", fs->device_name);
 181                 retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map);
 182                 if (retval)
 183                         goto cleanup;
 184                 retval = ext2fs_get_mem(do_image ? fs->blocksize :
 185                                         inode_nbytes, &inode_bitmap);
 186                 if (retval)
 187                         goto cleanup;
 188         } else
 189                 inode_nbytes = 0;
 190         ext2fs_free_mem(&buf);
 191
 192         if (fs->flags & EXT2_FLAG_IMAGE_FILE) {
 193                 blk = (fs->image_header->offset_inodemap / fs->blocksize);
 194                 ino_cnt = fs->super->s_inodes_count;
 195                 while (inode_nbytes > 0) {
 196                         retval = io_channel_read_blk(fs->image_io, blk++,
 197                                                      1, inode_bitmap);
 198                         if (retval)
 199                                 goto cleanup;
 200                         cnt = fs->blocksize << 3;
 201                         if (cnt > ino_cnt)
 202                                 cnt = ino_cnt;
 203                         retval = ext2fs_set_inode_bitmap_range(fs->inode_map,
 204                                                ino_itr, cnt, inode_bitmap);
 205                         if (retval)
 206                                 goto cleanup;
 207                         ino_itr += fs->blocksize << 3;
 208                         ino_cnt -= fs->blocksize << 3;
 209                         inode_nbytes -= fs->blocksize;
 210                 }
 211                 blk = (fs->image_header->offset_blockmap /
 212                        fs->blocksize);
 213                 blk_cnt = EXT2_BLOCKS_PER_GROUP(fs->super) *
 214                         fs->group_desc_count;
 215                 while (block_nbytes > 0) {
 216                         retval = io_channel_read_blk(fs->image_io, blk++,
 217                                                      1, block_bitmap);
 218                         if (retval)
 219                                 goto cleanup;
 220                         cnt = fs->blocksize << 3;
 221                         if (cnt > blk_cnt)
 222                                 cnt = blk_cnt;
 223                         retval = ext2fs_set_block_bitmap_range(fs->block_map,
 224                                        blk_itr, cnt, block_bitmap);
 225                         if (retval)
 226                                 goto cleanup;
 227                         blk_itr += fs->blocksize << 3;
 228                         blk_cnt -= fs->blocksize << 3;
 229                         block_nbytes -= fs->blocksize;
 230                 }
 231                 goto success_cleanup;
 232         }
 233
 234         for (i = 0; i < fs->group_desc_count; i++) {
 235                 if (block_bitmap) {
 236                         blk = fs->group_desc[i].bg_block_bitmap;
 237                         if (lazy_flag && fs->group_desc[i].bg_flags &
 238                             EXT2_BG_BLOCK_UNINIT &&
 239                             ext2fs_group_desc_csum_verify(fs, i))
 240                                 blk = 0;
 241                         if (blk) {
 242                                 retval = io_channel_read_blk(fs->io, blk,
 243                                              -block_nbytes, block_bitmap);
 244                                 if (retval) {
 245                                         retval = EXT2_ET_BLOCK_BITMAP_READ;
 246                                         goto cleanup;
 247                                 }
 248                         } else
 249                                 memset(block_bitmap, 0xff, block_nbytes);
 250                         cnt = block_nbytes << 3;
 251                         retval = ext2fs_set_block_bitmap_range(fs->block_map,
 252                                                blk_itr, cnt, block_bitmap);
 253                         if (retval)
 254                                 goto cleanup;
 255                         blk_itr += block_nbytes << 3;
 256                 }
 257                 if (inode_bitmap) {
 258                         blk = fs->group_desc[i].bg_inode_bitmap;
 259                         if (lazy_flag && fs->group_desc[i].bg_flags &
 260                             EXT2_BG_INODE_UNINIT &&
 261                             ext2fs_group_desc_csum_verify(fs, i))
 262                                 blk = 0;
 263                         if (blk) {
 264                                 retval = io_channel_read_blk(fs->io, blk,
 265                                              -inode_nbytes, inode_bitmap);
 266                                 if (retval) {
 267                                         retval = EXT2_ET_INODE_BITMAP_READ;
 268                                         goto cleanup;
 269                                 }
 270                         } else
 271                                 memset(inode_bitmap, 0xff, inode_nbytes);
 272                         cnt = inode_nbytes << 3;
 273                         retval = ext2fs_set_inode_bitmap_range(fs->inode_map,
 274                                                ino_itr, cnt, inode_bitmap);
 275                         if (retval)
 276                                 goto cleanup;
 277                         ino_itr += inode_nbytes << 3;
 278                 }
 279         }
 280 success_cleanup:
 281         if (inode_bitmap)
 282                 ext2fs_free_mem(&inode_bitmap);
 283         if (block_bitmap)
 284                 ext2fs_free_mem(&block_bitmap);
 285         return 0;
 286
 287 cleanup:
 288         if (do_block) {
 289                 ext2fs_free_mem(&fs->block_map);
 290                 fs->block_map = 0;
 291         }
 292         if (do_inode) {
 293                 ext2fs_free_mem(&fs->inode_map);
 294                 fs->inode_map = 0;
 295         }
 296         if (inode_bitmap)
 297                 ext2fs_free_mem(&inode_bitmap);
 298         if (block_bitmap)
 299                 ext2fs_free_mem(&block_bitmap);
 300         if (buf)
 301                 ext2fs_free_mem(&buf);
 302         return retval;
 303 }
 304
 305 errcode_t ext2fs_read_inode_bitmap(ext2_filsys fs)
 306 {
 307         return read_bitmaps(fs, 1, 0);
 308 }
 309
 310 errcode_t ext2fs_read_block_bitmap(ext2_filsys fs)
 311 {
 312         return read_bitmaps(fs, 0, 1);
 313 }
 314
 315 errcode_t ext2fs_write_inode_bitmap(ext2_filsys fs)
 316 {
 317         return write_bitmaps(fs, 1, 0);
 318 }
 319
 320 errcode_t ext2fs_write_block_bitmap (ext2_filsys fs)
 321 {
 322         return write_bitmaps(fs, 0, 1);
 323 }
 324
 325 errcode_t ext2fs_read_bitmaps(ext2_filsys fs)
 326 {
 327         if (fs->inode_map && fs->block_map)
 328                 return 0;
 329
 330         return read_bitmaps(fs, !fs->inode_map, !fs->block_map);
 331 }
 332
 333 errcode_t ext2fs_write_bitmaps(ext2_filsys fs)
 334 {
 335         int do_inode = fs->inode_map && ext2fs_test_ib_dirty(fs);
 336         int do_block = fs->block_map && ext2fs_test_bb_dirty(fs);
 337
 338         if (!do_inode && !do_block)
 339                 return 0;
 340
 341         return write_bitmaps(fs, do_inode, do_block);
 342 }