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270 lines
6.7 KiB
C
270 lines
6.7 KiB
C
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/*
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* swapfs.c --- byte-swap an ext2 filesystem
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*
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* Copyright 1996, 1997 by Theodore Ts'o
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*
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* %Begin-Header%
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* This file may be redistributed under the terms of the GNU Public
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* License.
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* %End-Header%
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*
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*/
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#ifdef HAVE_ERRNO_H
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#include <errno.h>
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#endif
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#include <et/com_err.h>
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#include "e2fsck.h"
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#ifdef ENABLE_SWAPFS
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struct swap_block_struct {
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ext2_ino_t ino;
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int isdir;
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errcode_t errcode;
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char *dir_buf;
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struct ext2_inode *inode;
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};
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/*
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* This is a helper function for block_iterate. We mark all of the
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* indirect and direct blocks as changed, so that block_iterate will
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* write them out.
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*/
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static int swap_block(ext2_filsys fs, blk_t *block_nr, int blockcnt,
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void *priv_data)
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{
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errcode_t retval;
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struct swap_block_struct *sb = (struct swap_block_struct *) priv_data;
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if (sb->isdir && (blockcnt >= 0) && *block_nr) {
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retval = ext2fs_read_dir_block(fs, *block_nr, sb->dir_buf);
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if (retval) {
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sb->errcode = retval;
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return BLOCK_ABORT;
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}
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retval = ext2fs_write_dir_block(fs, *block_nr, sb->dir_buf);
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if (retval) {
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sb->errcode = retval;
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return BLOCK_ABORT;
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}
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}
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if (blockcnt >= 0) {
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if (blockcnt < EXT2_NDIR_BLOCKS)
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return 0;
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return BLOCK_CHANGED;
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}
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if (blockcnt == BLOCK_COUNT_IND) {
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if (*block_nr == sb->inode->i_block[EXT2_IND_BLOCK])
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return 0;
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return BLOCK_CHANGED;
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}
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if (blockcnt == BLOCK_COUNT_DIND) {
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if (*block_nr == sb->inode->i_block[EXT2_DIND_BLOCK])
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return 0;
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return BLOCK_CHANGED;
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}
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if (blockcnt == BLOCK_COUNT_TIND) {
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if (*block_nr == sb->inode->i_block[EXT2_TIND_BLOCK])
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return 0;
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return BLOCK_CHANGED;
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}
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return BLOCK_CHANGED;
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}
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/*
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* This function is responsible for byte-swapping all of the indirect,
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* block pointers. It is also responsible for byte-swapping directories.
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*/
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static void swap_inode_blocks(e2fsck_t ctx, ext2_ino_t ino, char *block_buf,
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struct ext2_inode *inode)
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{
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errcode_t retval;
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struct swap_block_struct sb;
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sb.ino = ino;
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sb.inode = inode;
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sb.dir_buf = block_buf + ctx->fs->blocksize*3;
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sb.errcode = 0;
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sb.isdir = 0;
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if (LINUX_S_ISDIR(inode->i_mode))
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sb.isdir = 1;
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retval = ext2fs_block_iterate(ctx->fs, ino, 0, block_buf,
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swap_block, &sb);
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if (retval) {
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com_err("swap_inode_blocks", retval,
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_("while calling ext2fs_block_iterate"));
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ctx->flags |= E2F_FLAG_ABORT;
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return;
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}
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if (sb.errcode) {
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com_err("swap_inode_blocks", sb.errcode,
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_("while calling iterator function"));
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ctx->flags |= E2F_FLAG_ABORT;
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return;
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}
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}
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static void swap_inodes(e2fsck_t ctx)
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{
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ext2_filsys fs = ctx->fs;
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dgrp_t group;
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unsigned int i;
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ext2_ino_t ino = 1;
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char *buf, *block_buf;
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errcode_t retval;
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struct ext2_inode * inode;
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e2fsck_use_inode_shortcuts(ctx, 1);
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retval = ext2fs_get_mem(fs->blocksize * fs->inode_blocks_per_group,
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&buf);
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if (retval) {
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com_err("swap_inodes", retval,
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_("while allocating inode buffer"));
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ctx->flags |= E2F_FLAG_ABORT;
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return;
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}
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block_buf = (char *) e2fsck_allocate_memory(ctx, fs->blocksize * 4,
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"block interate buffer");
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for (group = 0; group < fs->group_desc_count; group++) {
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retval = io_channel_read_blk(fs->io,
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fs->group_desc[group].bg_inode_table,
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fs->inode_blocks_per_group, buf);
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if (retval) {
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com_err("swap_inodes", retval,
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_("while reading inode table (group %d)"),
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group);
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ctx->flags |= E2F_FLAG_ABORT;
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return;
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}
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inode = (struct ext2_inode *) buf;
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for (i=0; i < fs->super->s_inodes_per_group;
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i++, ino++, inode++) {
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ctx->stashed_ino = ino;
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ctx->stashed_inode = inode;
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if (fs->flags & EXT2_FLAG_SWAP_BYTES_READ)
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ext2fs_swap_inode(fs, inode, inode, 0);
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/*
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* Skip deleted files.
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*/
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if (inode->i_links_count == 0)
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continue;
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if (LINUX_S_ISDIR(inode->i_mode) ||
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((inode->i_block[EXT2_IND_BLOCK] ||
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inode->i_block[EXT2_DIND_BLOCK] ||
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inode->i_block[EXT2_TIND_BLOCK]) &&
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ext2fs_inode_has_valid_blocks(inode)))
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swap_inode_blocks(ctx, ino, block_buf, inode);
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if (ctx->flags & E2F_FLAG_SIGNAL_MASK)
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return;
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if (fs->flags & EXT2_FLAG_SWAP_BYTES_WRITE)
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ext2fs_swap_inode(fs, inode, inode, 1);
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}
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retval = io_channel_write_blk(fs->io,
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fs->group_desc[group].bg_inode_table,
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fs->inode_blocks_per_group, buf);
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if (retval) {
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com_err("swap_inodes", retval,
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_("while writing inode table (group %d)"),
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group);
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ctx->flags |= E2F_FLAG_ABORT;
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return;
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}
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}
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ext2fs_free_mem(&buf);
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ext2fs_free_mem(&block_buf);
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e2fsck_use_inode_shortcuts(ctx, 0);
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ext2fs_flush_icache(fs);
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}
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#if defined(__powerpc__) && defined(EXT2FS_ENABLE_SWAPFS)
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/*
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* On the PowerPC, the big-endian variant of the ext2 filesystem
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* has its bitmaps stored as 32-bit words with bit 0 as the LSB
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* of each word. Thus a bitmap with only bit 0 set would be, as
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* a string of bytes, 00 00 00 01 00 ...
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* To cope with this, we byte-reverse each word of a bitmap if
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* we have a big-endian filesystem, that is, if we are *not*
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* byte-swapping other word-sized numbers.
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*/
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#define EXT2_BIG_ENDIAN_BITMAPS
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#endif
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#ifdef EXT2_BIG_ENDIAN_BITMAPS
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static void ext2fs_swap_bitmap(ext2fs_generic_bitmap bmap)
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{
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__u32 *p = (__u32 *) bmap->bitmap;
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int n, nbytes = (bmap->end - bmap->start + 7) / 8;
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for (n = nbytes / sizeof(__u32); n > 0; --n, ++p)
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*p = ext2fs_swab32(*p);
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}
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#endif
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void swap_filesys(e2fsck_t ctx)
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{
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ext2_filsys fs = ctx->fs;
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#ifdef RESOURCE_TRACK
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struct resource_track rtrack;
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init_resource_track(&rtrack);
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#endif
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if (!(ctx->options & E2F_OPT_PREEN))
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printf(_("Pass 0: Doing byte-swap of filesystem\n"));
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#ifdef MTRACE
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mtrace_print("Byte swap");
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#endif
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if (fs->super->s_mnt_count) {
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fprintf(stderr, _("%s: the filesystem must be freshly "
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"checked using fsck\n"
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"and not mounted before trying to "
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"byte-swap it.\n"), ctx->device_name);
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ctx->flags |= E2F_FLAG_ABORT;
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return;
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}
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if (fs->flags & EXT2_FLAG_SWAP_BYTES) {
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fs->flags &= ~(EXT2_FLAG_SWAP_BYTES|
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EXT2_FLAG_SWAP_BYTES_WRITE);
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fs->flags |= EXT2_FLAG_SWAP_BYTES_READ;
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} else {
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fs->flags &= ~EXT2_FLAG_SWAP_BYTES_READ;
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fs->flags |= EXT2_FLAG_SWAP_BYTES_WRITE;
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}
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swap_inodes(ctx);
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if (ctx->flags & E2F_FLAG_SIGNAL_MASK)
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return;
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if (fs->flags & EXT2_FLAG_SWAP_BYTES_WRITE)
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fs->flags |= EXT2_FLAG_SWAP_BYTES;
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fs->flags &= ~(EXT2_FLAG_SWAP_BYTES_READ|
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EXT2_FLAG_SWAP_BYTES_WRITE);
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#ifdef EXT2_BIG_ENDIAN_BITMAPS
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e2fsck_read_bitmaps(ctx);
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ext2fs_swap_bitmap(fs->inode_map);
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ext2fs_swap_bitmap(fs->block_map);
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fs->flags |= EXT2_FLAG_BB_DIRTY | EXT2_FLAG_IB_DIRTY;
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#endif
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fs->flags &= ~EXT2_FLAG_MASTER_SB_ONLY;
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ext2fs_flush(fs);
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fs->flags |= EXT2_FLAG_MASTER_SB_ONLY;
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#ifdef RESOURCE_TRACK
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if (ctx->options & E2F_OPT_TIME2)
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print_resource_track(_("Byte swap"), &rtrack);
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#endif
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}
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#endif
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