lib/ext2fs/ind_block.c

   1 /*
   2  * ind_block.c --- indirect block I/O routines
   3  *
   4  * Copyright (C) 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000,
   5  *      2001, 2002, 2003, 2004, 2005 by  Theodore Ts'o.
   6  *
   7  * %Begin-Header%
   8  * This file may be redistributed under the terms of the GNU Public
   9  * License.
  10  * %End-Header%
  11  */
  12
  13 #include <stdio.h>
  14 #include <string.h>
  15 #if HAVE_UNISTD_H
  16 #include <unistd.h>
  17 #endif
  18
  19 #include "ext2_fs.h"
  20 #include "ext2fs.h"
  21
  22 errcode_t ext2fs_read_ind_block(ext2_filsys fs, blk_t blk, void *buf)
  23 {
  24         errcode_t       retval;
  25         blk_t           *block_nr;
  26         int             i;
  27         int             limit = fs->blocksize >> 2;
  28
  29         if ((fs->flags & EXT2_FLAG_IMAGE_FILE) &&
  30             (fs->io != fs->image_io))
  31                 memset(buf, 0, fs->blocksize);
  32         else {
  33                 retval = io_channel_read_blk(fs->io, blk, 1, buf);
  34                 if (retval)
  35                         retval;
  36         }
  37 #ifdef EXT2FS_ENABLE_SWAPFS
  38         if (fs->flags & (EXT2_FLAG_SWAP_BYTES | EXT2_FLAG_SWAP_BYTES_READ)) {
  39                 block_nr = (blk_t *) buf;
  40                 for (i = 0; i < limit; i++, block_nr++)
  41                         *block_nr = ext2fs_swab32(*block_nr);
  42         }
  43 #endif
  44         return 0;
  45 }
  46
  47 errcode_t ext2fs_write_ind_block(ext2_filsys fs, blk_t blk, void *buf)
  48 {
  49         blk_t           *block_nr;
  50         int             i;
  51         int             limit = fs->blocksize >> 2;
  52
  53         if (fs->flags & EXT2_FLAG_IMAGE_FILE)
  54                 return 0;
  55
  56 #ifdef EXT2FS_ENABLE_SWAPFS
  57         if (fs->flags & (EXT2_FLAG_SWAP_BYTES | EXT2_FLAG_SWAP_BYTES_WRITE)) {
  58                 block_nr = (blk_t *) buf;
  59                 for (i = 0; i < limit; i++, block_nr++)
  60                         *block_nr = ext2fs_swab32(*block_nr);
  61         }
  62 #endif
  63         return io_channel_write_blk(fs->io, blk, 1, buf);
  64 }
  65
  66