fs/reiserfs/dev.c

   1 /*
   2  *  (C) Copyright 2003 - 2004
   3  *  Sysgo AG, <www.elinos.com>, Pavel Bartusek <pba@sysgo.com>
   4  *
   5  *  This program is free software; you can redistribute it and/or modify
   6  *  it under the terms of the GNU General Public License as published by
   7  *  the Free Software Foundation; either version 2 of the License, or
   8  *  (at your option) any later version.
   9  *
  10  *  This program is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *  GNU General Public License for more details.
  14  *
  15  *  You should have received a copy of the GNU General Public License
  16  *  along with this program; if not, write to the Free Software
  17  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  18  */
  19
  20
  21 #include <common.h>
  22 #include <config.h>
  23 #include <reiserfs.h>
  24
  25 #include "reiserfs_private.h"
  26
  27 static block_dev_desc_t *reiserfs_block_dev_desc;
  28 static disk_partition_t part_info;
  29
  30
  31 int reiserfs_set_blk_dev(block_dev_desc_t *rbdd, int part)
  32 {
  33         reiserfs_block_dev_desc = rbdd;
  34
  35         if (part == 0) {
  36                 /* disk doesn't use partition table */
  37                 part_info.start = 0;
  38                 part_info.size = rbdd->lba;
  39                 part_info.blksz = rbdd->blksz;
  40         } else {
  41                 if (get_partition_info (reiserfs_block_dev_desc, part, &part_info)) {
  42                         return 0;
  43                 }
  44         }
  45         return (part_info.size);
  46 }
  47
  48
  49 int reiserfs_devread (int sector, int byte_offset, int byte_len, char *buf)
  50 {
  51         char sec_buf[SECTOR_SIZE];
  52         unsigned block_len;
  53 /*
  54         unsigned len = byte_len;
  55         u8 *start = buf;
  56 */
  57         /*
  58         *  Check partition boundaries
  59         */
  60         if (sector < 0
  61             || ((sector + ((byte_offset + byte_len - 1) >> SECTOR_BITS))
  62             >= part_info.size)) {
  63 /*              errnum = ERR_OUTSIDE_PART; */
  64                 printf (" ** reiserfs_devread() read outside partition\n");
  65                 return 0;
  66         }
  67
  68         /*
  69          *  Get the read to the beginning of a partition.
  70          */
  71         sector += byte_offset >> SECTOR_BITS;
  72         byte_offset &= SECTOR_SIZE - 1;
  73
  74 #if defined(DEBUG)
  75         printf (" <%d, %d, %d> ", sector, byte_offset, byte_len);
  76 #endif
  77
  78
  79         if (reiserfs_block_dev_desc == NULL)
  80                 return 0;
  81
  82
  83         if (byte_offset != 0) {
  84                 /* read first part which isn't aligned with start of sector */
  85                 if (reiserfs_block_dev_desc->block_read(reiserfs_block_dev_desc->dev,
  86                     part_info.start+sector, 1, (unsigned long *)sec_buf) != 1) {
  87                         printf (" ** reiserfs_devread() read error\n");
  88                         return 0;
  89                 }
  90                 memcpy(buf, sec_buf+byte_offset, min(SECTOR_SIZE-byte_offset, byte_len));
  91                 buf+=min(SECTOR_SIZE-byte_offset, byte_len);
  92                 byte_len-=min(SECTOR_SIZE-byte_offset, byte_len);
  93                 sector++;
  94         }
  95
  96         /* read sector aligned part */
  97         block_len = byte_len & ~(SECTOR_SIZE-1);
  98         if (reiserfs_block_dev_desc->block_read(reiserfs_block_dev_desc->dev,
  99             part_info.start+sector, block_len/SECTOR_SIZE, (unsigned long *)buf) !=
 100             block_len/SECTOR_SIZE) {
 101                 printf (" ** reiserfs_devread() read error - block\n");
 102                 return 0;
 103         }
 104         buf+=block_len;
 105         byte_len-=block_len;
 106         sector+= block_len/SECTOR_SIZE;
 107
 108         if ( byte_len != 0 ) {
 109                 /* read rest of data which are not in whole sector */
 110                 if (reiserfs_block_dev_desc->block_read(reiserfs_block_dev_desc->dev,
 111                     part_info.start+sector, 1, (unsigned long *)sec_buf) != 1) {
 112                         printf (" ** reiserfs_devread() read error - last part\n");
 113                         return 0;
 114                 }
 115                 memcpy(buf, sec_buf, byte_len);
 116         }
 117
 118         return 1;
 119 }