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/*
* swapfs.c --- byte-swap an ext2 filesystem
*
* Copyright 1996, 1997 by Theodore Ts'o
*
* %Begin-Header%
* This file may be redistributed under the terms of the GNU Public
* License.
* %End-Header%
*
*/
#ifdef HAVE_ERRNO_H
#include <errno.h>
#endif
#include <et/com_err.h>
#include "e2fsck.h"
#ifdef ENABLE_SWAPFS
struct swap_block_struct {
ext2_ino_t ino;
int isdir;
errcode_t errcode;
char *dir_buf;
struct ext2_inode *inode;
};
/*
* This is a helper function for block_iterate. We mark all of the
* indirect and direct blocks as changed, so that block_iterate will
* write them out.
*/
static int swap_block(ext2_filsys fs, blk_t *block_nr, int blockcnt,
void *priv_data)
{
errcode_t retval;
struct swap_block_struct *sb = (struct swap_block_struct *) priv_data;
if (sb->isdir && (blockcnt >= 0) && *block_nr) {
retval = ext2fs_read_dir_block(fs, *block_nr, sb->dir_buf);
if (retval) {
sb->errcode = retval;
return BLOCK_ABORT;
}
retval = ext2fs_write_dir_block(fs, *block_nr, sb->dir_buf);
if (retval) {
sb->errcode = retval;
return BLOCK_ABORT;
}
}
if (blockcnt >= 0) {
if (blockcnt < EXT2_NDIR_BLOCKS)
return 0;
return BLOCK_CHANGED;
}
if (blockcnt == BLOCK_COUNT_IND) {
if (*block_nr == sb->inode->i_block[EXT2_IND_BLOCK])
return 0;
return BLOCK_CHANGED;
}
if (blockcnt == BLOCK_COUNT_DIND) {
if (*block_nr == sb->inode->i_block[EXT2_DIND_BLOCK])
return 0;
return BLOCK_CHANGED;
}
if (blockcnt == BLOCK_COUNT_TIND) {
if (*block_nr == sb->inode->i_block[EXT2_TIND_BLOCK])
return 0;
return BLOCK_CHANGED;
}
return BLOCK_CHANGED;
}
/*
* This function is responsible for byte-swapping all of the indirect,
* block pointers. It is also responsible for byte-swapping directories.
*/
static void swap_inode_blocks(e2fsck_t ctx, ext2_ino_t ino, char *block_buf,
struct ext2_inode *inode)
{
errcode_t retval;
struct swap_block_struct sb;
sb.ino = ino;
sb.inode = inode;
sb.dir_buf = block_buf + ctx->fs->blocksize*3;
sb.errcode = 0;
sb.isdir = 0;
if (LINUX_S_ISDIR(inode->i_mode))
sb.isdir = 1;
retval = ext2fs_block_iterate(ctx->fs, ino, 0, block_buf,
swap_block, &sb);
if (retval) {
com_err("swap_inode_blocks", retval,
_("while calling ext2fs_block_iterate"));
ctx->flags |= E2F_FLAG_ABORT;
return;
}
if (sb.errcode) {
com_err("swap_inode_blocks", sb.errcode,
_("while calling iterator function"));
ctx->flags |= E2F_FLAG_ABORT;
return;
}
}
static void swap_inodes(e2fsck_t ctx)
{
ext2_filsys fs = ctx->fs;
dgrp_t group;
unsigned int i;
ext2_ino_t ino = 1;
char *buf, *block_buf;
errcode_t retval;
struct ext2_inode * inode;
e2fsck_use_inode_shortcuts(ctx, 1);
retval = ext2fs_get_mem(fs->blocksize * fs->inode_blocks_per_group,
&buf);
if (retval) {
com_err("swap_inodes", retval,
_("while allocating inode buffer"));
ctx->flags |= E2F_FLAG_ABORT;
return;
}
block_buf = (char *) e2fsck_allocate_memory(ctx, fs->blocksize * 4,
"block interate buffer");
for (group = 0; group < fs->group_desc_count; group++) {
retval = io_channel_read_blk(fs->io,
fs->group_desc[group].bg_inode_table,
fs->inode_blocks_per_group, buf);
if (retval) {
com_err("swap_inodes", retval,
_("while reading inode table (group %d)"),
group);
ctx->flags |= E2F_FLAG_ABORT;
return;
}
inode = (struct ext2_inode *) buf;
for (i=0; i < fs->super->s_inodes_per_group;
i++, ino++, inode++) {
ctx->stashed_ino = ino;
ctx->stashed_inode = inode;
if (fs->flags & EXT2_FLAG_SWAP_BYTES_READ)
ext2fs_swap_inode(fs, inode, inode, 0);
/*
* Skip deleted files.
*/
if (inode->i_links_count == 0)
continue;
if (LINUX_S_ISDIR(inode->i_mode) ||
((inode->i_block[EXT2_IND_BLOCK] ||
inode->i_block[EXT2_DIND_BLOCK] ||
inode->i_block[EXT2_TIND_BLOCK]) &&
ext2fs_inode_has_valid_blocks(inode)))
swap_inode_blocks(ctx, ino, block_buf, inode);
if (ctx->flags & E2F_FLAG_SIGNAL_MASK)
return;
if (fs->flags & EXT2_FLAG_SWAP_BYTES_WRITE)
ext2fs_swap_inode(fs, inode, inode, 1);
}
retval = io_channel_write_blk(fs->io,
fs->group_desc[group].bg_inode_table,
fs->inode_blocks_per_group, buf);
if (retval) {
com_err("swap_inodes", retval,
_("while writing inode table (group %d)"),
group);
ctx->flags |= E2F_FLAG_ABORT;
return;
}
}
ext2fs_free_mem(&buf);
ext2fs_free_mem(&block_buf);
e2fsck_use_inode_shortcuts(ctx, 0);
ext2fs_flush_icache(fs);
}
#if defined(__powerpc__) && defined(EXT2FS_ENABLE_SWAPFS)
/*
* 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(ext2fs_generic_bitmap bmap)
{
__u32 *p = (__u32 *) bmap->bitmap;
int n, nbytes = (bmap->end - bmap->start + 7) / 8;
for (n = nbytes / sizeof(__u32); n > 0; --n, ++p)
*p = ext2fs_swab32(*p);
}
#endif
void swap_filesys(e2fsck_t ctx)
{
ext2_filsys fs = ctx->fs;
#ifdef RESOURCE_TRACK
struct resource_track rtrack;
init_resource_track(&rtrack);
#endif
if (!(ctx->options & E2F_OPT_PREEN))
printf(_("Pass 0: Doing byte-swap of filesystem\n"));
#ifdef MTRACE
mtrace_print("Byte swap");
#endif
if (fs->super->s_mnt_count) {
fprintf(stderr, _("%s: the filesystem must be freshly "
"checked using fsck\n"
"and not mounted before trying to "
"byte-swap it.\n"), ctx->device_name);
ctx->flags |= E2F_FLAG_ABORT;
return;
}
if (fs->flags & EXT2_FLAG_SWAP_BYTES) {
fs->flags &= ~(EXT2_FLAG_SWAP_BYTES|
EXT2_FLAG_SWAP_BYTES_WRITE);
fs->flags |= EXT2_FLAG_SWAP_BYTES_READ;
} else {
fs->flags &= ~EXT2_FLAG_SWAP_BYTES_READ;
fs->flags |= EXT2_FLAG_SWAP_BYTES_WRITE;
}
swap_inodes(ctx);
if (ctx->flags & E2F_FLAG_SIGNAL_MASK)
return;
if (fs->flags & EXT2_FLAG_SWAP_BYTES_WRITE)
fs->flags |= EXT2_FLAG_SWAP_BYTES;
fs->flags &= ~(EXT2_FLAG_SWAP_BYTES_READ|
EXT2_FLAG_SWAP_BYTES_WRITE);
#ifdef EXT2_BIG_ENDIAN_BITMAPS
e2fsck_read_bitmaps(ctx);
ext2fs_swap_bitmap(fs->inode_map);
ext2fs_swap_bitmap(fs->block_map);
fs->flags |= EXT2_FLAG_BB_DIRTY | EXT2_FLAG_IB_DIRTY;
#endif
fs->flags &= ~EXT2_FLAG_MASTER_SB_ONLY;
ext2fs_flush(fs);
fs->flags |= EXT2_FLAG_MASTER_SB_ONLY;
#ifdef RESOURCE_TRACK
if (ctx->options & E2F_OPT_TIME2)
print_resource_track(_("Byte swap"), &rtrack);
#endif
}
#endif
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