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