/*
 * 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"

struct swap_block_struct {
	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 *private)
{
	errcode_t	retval;
	
	struct swap_block_struct *sb = (struct swap_block_struct *) private;

	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(ext2_filsys fs, 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 + fs->blocksize*3;
	sb.errcode = 0;
	sb.isdir = 0;
	if (LINUX_S_ISDIR(inode->i_mode))
		sb.isdir = 1;

	retval = ext2fs_block_iterate(fs, ino, 0, block_buf, swap_block, &sb);
	if (retval) {
		com_err("swap_inode_blocks", retval,
			"while calling ext2fs_block_iterate");
		fatal_error(0);
	}
	if (sb.errcode) {
		com_err("swap_inode_blocks", sb.errcode,
			"while calling iterator function");
		fatal_error(0);
	}
}

static void swap_inodes(ext2_filsys fs)
{
	int			i, group;
	ino_t			ino = 1;
	char 			*buf, *block_buf;
	errcode_t		retval;
	struct ext2_inode *	inode;

	fs->read_inode = pass1_read_inode;
	fs->get_blocks = pass1_get_blocks;
	

	buf = malloc(fs->blocksize * fs->inode_blocks_per_group);
	if (!buf) {
		com_err("swap_inodes", ENOMEM,
			"while allocating inode buffer");
		fatal_error(0);
	}
	block_buf = allocate_memory(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);
			fatal_error(0);
		}
		inode = (struct ext2_inode *) buf;
		for (i=0; i < fs->super->s_inodes_per_group;
		     i++, ino++, inode++) {
			stashed_ino = ino;
			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(fs, ino, block_buf, inode);
			
			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);
			fatal_error(0);
		}
	}
	free(buf);
	free(block_buf);
	fs->read_inode = 0;
	fs->get_blocks = 0;
}

void swap_filesys(ext2_filsys fs)
{
	struct resource_track	rtrack;

	init_resource_track(&rtrack);

	if (!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", device_name);
		fatal_error(0);
	}
	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(fs);
	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);
	ext2fs_flush(fs);
	
	if (tflag > 1) {
		printf("Byte swap: ");
		print_resource_track(&rtrack);
	}
}