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/* vi: set sw=4 ts=4: */
/*
* rw_bitmaps.c --- routines to read and write the inode and block bitmaps.
*
* Copyright (C) 1993, 1994, 1994, 1996 Theodore Ts'o.
*
* %Begin-Header%
* This file may be redistributed under the terms of the GNU Public
* License.
* %End-Header%
*/
#include <stdio.h>
#include <string.h>
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <fcntl.h>
#include <time.h>
#ifdef HAVE_SYS_STAT_H
#include <sys/stat.h>
#endif
#ifdef HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#include "ext2_fs.h"
#include "ext2fs.h"
#include "e2image.h"
#if defined(__powerpc__) && BB_BIG_ENDIAN
/*
* On the PowerPC, the big-endian variant of the ext2 filesystem
* has its bitmaps stored as 32-bit words with bit 0 as the LSB
* of each word. Thus a bitmap with only bit 0 set would be, as
* a string of bytes, 00 00 00 01 00 ...
* To cope with this, we byte-reverse each word of a bitmap if
* we have a big-endian filesystem, that is, if we are *not*
* byte-swapping other word-sized numbers.
*/
#define EXT2_BIG_ENDIAN_BITMAPS
#endif
#ifdef EXT2_BIG_ENDIAN_BITMAPS
static void ext2fs_swap_bitmap(ext2_filsys fs, char *bitmap, int nbytes)
{
__u32 *p = (__u32 *) bitmap;
int n;
for (n = nbytes / sizeof(__u32); n > 0; --n, ++p)
*p = ext2fs_swab32(*p);
}
#endif
errcode_t ext2fs_write_inode_bitmap(ext2_filsys fs)
{
dgrp_t i;
size_t nbytes;
errcode_t retval;
char * inode_bitmap = fs->inode_map->bitmap;
char * bitmap_block = NULL;
blk_t blk;
EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
if (!(fs->flags & EXT2_FLAG_RW))
return EXT2_ET_RO_FILSYS;
if (!inode_bitmap)
return 0;
nbytes = (size_t) ((EXT2_INODES_PER_GROUP(fs->super)+7) / 8);
retval = ext2fs_get_mem(fs->blocksize, &bitmap_block);
if (retval)
return retval;
memset(bitmap_block, 0xff, fs->blocksize);
for (i = 0; i < fs->group_desc_count; i++) {
memcpy(bitmap_block, inode_bitmap, nbytes);
blk = fs->group_desc[i].bg_inode_bitmap;
if (blk) {
#ifdef EXT2_BIG_ENDIAN_BITMAPS
if (!((fs->flags & EXT2_FLAG_SWAP_BYTES) ||
(fs->flags & EXT2_FLAG_SWAP_BYTES_WRITE)))
ext2fs_swap_bitmap(fs, bitmap_block, nbytes);
#endif
retval = io_channel_write_blk(fs->io, blk, 1,
bitmap_block);
if (retval)
return EXT2_ET_INODE_BITMAP_WRITE;
}
inode_bitmap += nbytes;
}
fs->flags &= ~EXT2_FLAG_IB_DIRTY;
ext2fs_free_mem(&bitmap_block);
return 0;
}
errcode_t ext2fs_write_block_bitmap (ext2_filsys fs)
{
dgrp_t i;
unsigned int j;
int nbytes;
unsigned int nbits;
errcode_t retval;
char * block_bitmap = fs->block_map->bitmap;
char * bitmap_block = NULL;
blk_t blk;
EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
if (!(fs->flags & EXT2_FLAG_RW))
return EXT2_ET_RO_FILSYS;
if (!block_bitmap)
return 0;
nbytes = EXT2_BLOCKS_PER_GROUP(fs->super) / 8;
retval = ext2fs_get_mem(fs->blocksize, &bitmap_block);
if (retval)
return retval;
memset(bitmap_block, 0xff, fs->blocksize);
for (i = 0; i < fs->group_desc_count; i++) {
memcpy(bitmap_block, block_bitmap, nbytes);
if (i == fs->group_desc_count - 1) {
/* Force bitmap padding for the last group */
nbits = ((fs->super->s_blocks_count
- fs->super->s_first_data_block)
% EXT2_BLOCKS_PER_GROUP(fs->super));
if (nbits)
for (j = nbits; j < fs->blocksize * 8; j++)
ext2fs_set_bit(j, bitmap_block);
}
blk = fs->group_desc[i].bg_block_bitmap;
if (blk) {
#ifdef EXT2_BIG_ENDIAN_BITMAPS
if (!((fs->flags & EXT2_FLAG_SWAP_BYTES) ||
(fs->flags & EXT2_FLAG_SWAP_BYTES_WRITE)))
ext2fs_swap_bitmap(fs, bitmap_block, nbytes);
#endif
retval = io_channel_write_blk(fs->io, blk, 1,
bitmap_block);
if (retval)
return EXT2_ET_BLOCK_BITMAP_WRITE;
}
block_bitmap += nbytes;
}
fs->flags &= ~EXT2_FLAG_BB_DIRTY;
ext2fs_free_mem(&bitmap_block);
return 0;
}
static errcode_t read_bitmaps(ext2_filsys fs, int do_inode, int do_block)
{
dgrp_t i;
char *block_bitmap = NULL, *inode_bitmap = NULL;
char *buf;
errcode_t retval;
int block_nbytes = (int) EXT2_BLOCKS_PER_GROUP(fs->super) / 8;
int inode_nbytes = (int) EXT2_INODES_PER_GROUP(fs->super) / 8;
blk_t blk;
EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
fs->write_bitmaps = ext2fs_write_bitmaps;
retval = ext2fs_get_mem(strlen(fs->device_name) + 80, &buf);
if (retval)
return retval;
if (do_block) {
ext2fs_free_block_bitmap(fs->block_map);
sprintf(buf, "block bitmap for %s", fs->device_name);
retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map);
if (retval)
goto cleanup;
block_bitmap = fs->block_map->bitmap;
}
if (do_inode) {
ext2fs_free_inode_bitmap(fs->inode_map);
sprintf(buf, "inode bitmap for %s", fs->device_name);
retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map);
if (retval)
goto cleanup;
inode_bitmap = fs->inode_map->bitmap;
}
ext2fs_free_mem(&buf);
if (fs->flags & EXT2_FLAG_IMAGE_FILE) {
if (inode_bitmap) {
blk = (fs->image_header->offset_inodemap /
fs->blocksize);
retval = io_channel_read_blk(fs->image_io, blk,
-(inode_nbytes * fs->group_desc_count),
inode_bitmap);
if (retval)
goto cleanup;
}
if (block_bitmap) {
blk = (fs->image_header->offset_blockmap /
fs->blocksize);
retval = io_channel_read_blk(fs->image_io, blk,
-(block_nbytes * fs->group_desc_count),
block_bitmap);
if (retval)
goto cleanup;
}
return 0;
}
for (i = 0; i < fs->group_desc_count; i++) {
if (block_bitmap) {
blk = fs->group_desc[i].bg_block_bitmap;
if (blk) {
retval = io_channel_read_blk(fs->io, blk,
-block_nbytes, block_bitmap);
if (retval) {
retval = EXT2_ET_BLOCK_BITMAP_READ;
goto cleanup;
}
#ifdef EXT2_BIG_ENDIAN_BITMAPS
if (!((fs->flags & EXT2_FLAG_SWAP_BYTES) ||
(fs->flags & EXT2_FLAG_SWAP_BYTES_READ)))
ext2fs_swap_bitmap(fs, block_bitmap, block_nbytes);
#endif
} else
memset(block_bitmap, 0, block_nbytes);
block_bitmap += block_nbytes;
}
if (inode_bitmap) {
blk = fs->group_desc[i].bg_inode_bitmap;
if (blk) {
retval = io_channel_read_blk(fs->io, blk,
-inode_nbytes, inode_bitmap);
if (retval) {
retval = EXT2_ET_INODE_BITMAP_READ;
goto cleanup;
}
#ifdef EXT2_BIG_ENDIAN_BITMAPS
if (!((fs->flags & EXT2_FLAG_SWAP_BYTES) ||
(fs->flags & EXT2_FLAG_SWAP_BYTES_READ)))
ext2fs_swap_bitmap(fs, inode_bitmap, inode_nbytes);
#endif
} else
memset(inode_bitmap, 0, inode_nbytes);
inode_bitmap += inode_nbytes;
}
}
return 0;
cleanup:
if (do_block) {
ext2fs_free_mem(&fs->block_map);
}
if (do_inode) {
ext2fs_free_mem(&fs->inode_map);
}
ext2fs_free_mem(&buf);
return retval;
}
errcode_t ext2fs_read_inode_bitmap (ext2_filsys fs)
{
return read_bitmaps(fs, 1, 0);
}
errcode_t ext2fs_read_block_bitmap(ext2_filsys fs)
{
return read_bitmaps(fs, 0, 1);
}
errcode_t ext2fs_read_bitmaps(ext2_filsys fs)
{
EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
if (fs->inode_map && fs->block_map)
return 0;
return read_bitmaps(fs, !fs->inode_map, !fs->block_map);
}
errcode_t ext2fs_write_bitmaps(ext2_filsys fs)
{
errcode_t retval;
EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
if (fs->block_map && ext2fs_test_bb_dirty(fs)) {
retval = ext2fs_write_block_bitmap(fs);
if (retval)
return retval;
}
if (fs->inode_map && ext2fs_test_ib_dirty(fs)) {
retval = ext2fs_write_inode_bitmap(fs);
if (retval)
return retval;
}
return 0;
}
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