lib/ext2fs/rs_bitmap.c

   1 /*
   2  * rs_bitmap.c --- routine for changing the size of a bitmap
   3  *
   4  * Copyright (C) 1996, 1997 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 #if EXT2_FLAT_INCLUDES
  27 #include "ext2_fs.h"
  28 #else
  29 #include <linux/ext2_fs.h>
  30 #endif
  31
  32 #include "ext2fs.h"
  33
  34 errcode_t ext2fs_resize_generic_bitmap(__u32 new_end, __u32 new_real_end,
  35                                        ext2fs_generic_bitmap bmap)
  36 {
  37         errcode_t       retval;
  38         size_t          size, new_size;
  39         __u32           bitno;
  40
  41         if (!bmap)
  42                 return EXT2_ET_INVALID_ARGUMENT;
  43
  44         EXT2_CHECK_MAGIC(bmap, EXT2_ET_MAGIC_GENERIC_BITMAP);
  45
  46         /*
  47          * If we're expanding the bitmap, make sure all of the new
  48          * parts of the bitmap are zero.
  49          */
  50         if (new_end > bmap->end) {
  51                 bitno = bmap->real_end;
  52                 if (bitno > new_end)
  53                         bitno = new_end;
  54                 for (; bitno > bmap->end; bitno--)
  55                         ext2fs_clear_bit(bitno - bmap->start, bmap->bitmap);
  56         }
  57         if (new_real_end == bmap->real_end) {
  58                 bmap->end = new_end;
  59                 return 0;
  60         }
  61
  62         size = ((bmap->real_end - bmap->start) / 8) + 1;
  63         new_size = ((new_real_end - bmap->start) / 8) + 1;
  64
  65         if (size != new_size) {
  66                 retval = ext2fs_resize_mem(size, new_size,
  67                                            (void **) &bmap->bitmap);
  68                 if (retval)
  69                         return retval;
  70         }
  71         if (new_size > size)
  72                 memset(bmap->bitmap + size, 0, new_size - size);
  73
  74         bmap->end = new_end;
  75         bmap->real_end = new_real_end;
  76         return 0;
  77 }
  78
  79 errcode_t ext2fs_resize_inode_bitmap(__u32 new_end, __u32 new_real_end,
  80                                      ext2fs_inode_bitmap bmap)
  81 {
  82         errcode_t       retval;
  83
  84         if (!bmap)
  85                 return EXT2_ET_INVALID_ARGUMENT;
  86
  87         EXT2_CHECK_MAGIC(bmap, EXT2_ET_MAGIC_INODE_BITMAP);
  88
  89         bmap->magic = EXT2_ET_MAGIC_GENERIC_BITMAP;
  90         retval = ext2fs_resize_generic_bitmap(new_end, new_real_end,
  91                                               bmap);
  92         bmap->magic = EXT2_ET_MAGIC_INODE_BITMAP;
  93         return retval;
  94 }
  95
  96 errcode_t ext2fs_resize_block_bitmap(__u32 new_end, __u32 new_real_end,
  97                                      ext2fs_block_bitmap bmap)
  98 {
  99         errcode_t       retval;
 100
 101         if (!bmap)
 102                 return EXT2_ET_INVALID_ARGUMENT;
 103
 104         EXT2_CHECK_MAGIC(bmap, EXT2_ET_MAGIC_BLOCK_BITMAP);
 105
 106         bmap->magic = EXT2_ET_MAGIC_GENERIC_BITMAP;
 107         retval = ext2fs_resize_generic_bitmap(new_end, new_real_end,
 108                                               bmap);
 109         bmap->magic = EXT2_ET_MAGIC_BLOCK_BITMAP;
 110         return retval;
 111 }
 112