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 <stdlib.h>
  18 #include <fcntl.h>
  19 #include <time.h>
  20 #include <sys/stat.h>
  21 #include <sys/types.h>
  22 #if HAVE_ERRNO_H
  23 #include <errno.h>
  24 #endif
  25
  26 #include <linux/ext2_fs.h>
  27
  28 #include "ext2fs.h"
  29
  30 errcode_t ext2fs_write_inode_bitmap(ext2_filsys fs)
  31 {
  32         int             i;
  33         size_t          nbytes;
  34         errcode_t       retval;
  35         char * inode_bitmap = fs->inode_map->bitmap;
  36         char * bitmap_block = NULL;
  37         blk_t           blk;
  38
  39         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
  40
  41         if (!(fs->flags & EXT2_FLAG_RW))
  42                 return EXT2_ET_RO_FILSYS;
  43         if (!inode_bitmap)
  44                 return 0;
  45         nbytes = (size_t) ((EXT2_INODES_PER_GROUP(fs->super)+7) / 8);
  46
  47         bitmap_block = malloc(fs->blocksize);
  48         if (!bitmap_block)
  49                 return ENOMEM;
  50         memset(bitmap_block, 0xff, fs->blocksize);
  51         for (i = 0; i < fs->group_desc_count; i++) {
  52                 memcpy(bitmap_block, inode_bitmap, nbytes);
  53                 blk = fs->group_desc[i].bg_inode_bitmap;
  54                 if (blk) {
  55                         retval = io_channel_write_blk(fs->io, blk, 1,
  56                                                       bitmap_block);
  57                         if (retval)
  58                                 return EXT2_ET_INODE_BITMAP_WRITE;
  59                 }
  60                 inode_bitmap += nbytes;
  61         }
  62         fs->flags |= EXT2_FLAG_CHANGED;
  63         fs->flags &= ~EXT2_FLAG_IB_DIRTY;
  64         free(bitmap_block);
  65         return 0;
  66 }
  67
  68 errcode_t ext2fs_write_block_bitmap (ext2_filsys fs)
  69 {
  70         int             i;
  71         int             j;
  72         int             nbytes;
  73         int             nbits;
  74         errcode_t       retval;
  75         char * block_bitmap = fs->block_map->bitmap;
  76         char * bitmap_block = NULL;
  77         blk_t           blk;
  78
  79         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
  80
  81         if (!(fs->flags & EXT2_FLAG_RW))
  82                 return EXT2_ET_RO_FILSYS;
  83         if (!block_bitmap)
  84                 return 0;
  85         nbytes = EXT2_BLOCKS_PER_GROUP(fs->super) / 8;
  86         bitmap_block = malloc(fs->blocksize);
  87         if (!bitmap_block)
  88                 return ENOMEM;
  89         memset(bitmap_block, 0xff, fs->blocksize);
  90         for (i = 0; i < fs->group_desc_count; i++) {
  91                 memcpy(bitmap_block, block_bitmap, nbytes);
  92                 if (i == fs->group_desc_count - 1) {
  93                         /* Force bitmap padding for the last group */
  94                         nbits = (int) ((fs->super->s_blocks_count
  95                                         - fs->super->s_first_data_block)
  96                                        % EXT2_BLOCKS_PER_GROUP(fs->super));
  97                         if (nbits)
  98                                 for (j = nbits; j < fs->blocksize * 8; j++)
  99                                         ext2fs_set_bit(j, bitmap_block);
 100                 }
 101                 blk = fs->group_desc[i].bg_block_bitmap;
 102                 if (blk) {
 103                         retval = io_channel_write_blk(fs->io, blk, 1,
 104                                                       bitmap_block);
 105                         if (retval)
 106                                 return EXT2_ET_BLOCK_BITMAP_WRITE;
 107                 }
 108                 block_bitmap += nbytes;
 109         }
 110         fs->flags |= EXT2_FLAG_CHANGED;
 111         fs->flags &= ~EXT2_FLAG_BB_DIRTY;
 112         free(bitmap_block);
 113         return 0;
 114 }
 115
 116 static errcode_t read_bitmaps(ext2_filsys fs, int do_inode, int do_block)
 117 {
 118         int i;
 119         char *block_bitmap = 0, *inode_bitmap = 0;
 120         char *buf;
 121         errcode_t retval;
 122         int block_nbytes = (int) EXT2_BLOCKS_PER_GROUP(fs->super) / 8;
 123         int inode_nbytes = (int) EXT2_INODES_PER_GROUP(fs->super) / 8;
 124         blk_t   blk;
 125
 126         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 127
 128         fs->write_bitmaps = ext2fs_write_bitmaps;
 129
 130         buf = malloc(strlen(fs->device_name) + 80);
 131         if (do_block) {
 132                 if (fs->block_map)
 133                         ext2fs_free_block_bitmap(fs->block_map);
 134                 sprintf(buf, "block bitmap for %s", fs->device_name);
 135                 retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map);
 136                 if (retval)
 137                         goto cleanup;
 138                 block_bitmap = fs->block_map->bitmap;
 139         }
 140         if (do_inode) {
 141                 if (fs->inode_map)
 142                         ext2fs_free_inode_bitmap(fs->inode_map);
 143                 sprintf(buf, "inode bitmap for %s", fs->device_name);
 144                 retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map);
 145                 if (retval)
 146                         goto cleanup;
 147                 inode_bitmap = fs->inode_map->bitmap;
 148         }
 149         free(buf);
 150
 151         for (i = 0; i < fs->group_desc_count; i++) {
 152                 if (block_bitmap) {
 153                         blk = fs->group_desc[i].bg_block_bitmap;
 154                         if (blk) {
 155                                 retval = io_channel_read_blk(fs->io, blk,
 156                                              -block_nbytes, block_bitmap);
 157                                 if (retval) {
 158                                         retval = EXT2_ET_BLOCK_BITMAP_READ;
 159                                         goto cleanup;
 160                                 }
 161                         } else
 162                                 memset(block_bitmap, 0, block_nbytes);
 163                         block_bitmap += block_nbytes;
 164                 }
 165                 if (inode_bitmap) {
 166                         blk = fs->group_desc[i].bg_inode_bitmap;
 167                         if (blk) {
 168                                 retval = io_channel_read_blk(fs->io, blk,
 169                                              -inode_nbytes, inode_bitmap);
 170                                 if (retval) {
 171                                         retval = EXT2_ET_INODE_BITMAP_READ;
 172                                         goto cleanup;
 173                                 }
 174                         } else
 175                                 memset(inode_bitmap, 0, inode_nbytes);
 176                         inode_bitmap += inode_nbytes;
 177                 }
 178         }
 179         return 0;
 180
 181 cleanup:
 182         if (do_block) {
 183                 free(fs->block_map);
 184                 fs->block_map = 0;
 185         }
 186         if (do_inode) {
 187                 free(fs->inode_map);
 188                 fs->inode_map = 0;
 189         }
 190         if (buf)
 191                 free(buf);
 192         return retval;
 193 }
 194
 195 errcode_t ext2fs_read_inode_bitmap (ext2_filsys fs)
 196 {
 197         return read_bitmaps(fs, 1, 0);
 198 }
 199
 200 errcode_t ext2fs_read_block_bitmap(ext2_filsys fs)
 201 {
 202         return read_bitmaps(fs, 0, 1);
 203 }
 204
 205 errcode_t ext2fs_read_bitmaps(ext2_filsys fs)
 206 {
 207
 208         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 209
 210         return read_bitmaps(fs, !fs->inode_map, !fs->block_map);
 211 }
 212
 213 errcode_t ext2fs_write_bitmaps(ext2_filsys fs)
 214 {
 215         errcode_t       retval;
 216
 217         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 218
 219         if (fs->block_map && ext2fs_test_bb_dirty(fs)) {
 220                 retval = ext2fs_write_block_bitmap(fs);
 221                 if (retval)
 222                         return retval;
 223         }
 224         if (fs->inode_map && ext2fs_test_ib_dirty(fs)) {
 225                 retval = ext2fs_write_inode_bitmap(fs);
 226                 if (retval)
 227                         return retval;
 228         }
 229         return 0;
 230 }
 231