/* vi: set sw=4 ts=4: *//* * closefs.c --- close an ext2 filesystem * * Copyright (C) 1993, 1994, 1995, 1996 Theodore Ts'o. * * %Begin-Header% * This file may be redistributed under the terms of the GNU Public * License. * %End-Header% */#include <stdio.h>#if HAVE_UNISTD_H#include <unistd.h>#endif#include <time.h>#include <string.h>#include "ext2_fs.h"#include "ext2fsP.h"static int test_root(int a, int b){	if (a == 0)		return 1;	while (1) {		if (a == 1)			return 1;		if (a % b)			return 0;		a = a / b;	}}int ext2fs_bg_has_super(ext2_filsys fs, int group_block){	if (!(fs->super->s_feature_ro_compat &	      EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER))		return 1;	if (test_root(group_block, 3) || (test_root(group_block, 5)) ||	    test_root(group_block, 7))		return 1;	return 0;}int ext2fs_super_and_bgd_loc(ext2_filsys fs,			     dgrp_t group,			     blk_t *ret_super_blk,			     blk_t *ret_old_desc_blk,			     blk_t *ret_new_desc_blk,			     int *ret_meta_bg){	blk_t	group_block, super_blk = 0, old_desc_blk = 0, new_desc_blk = 0;	unsigned int meta_bg, meta_bg_size;	int	numblocks, has_super;	int	old_desc_blocks;	group_block = fs->super->s_first_data_block +		(group * fs->super->s_blocks_per_group);	if (fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG)		old_desc_blocks = fs->super->s_first_meta_bg;	else		old_desc_blocks =			fs->desc_blocks + fs->super->s_reserved_gdt_blocks;	if (group == fs->group_desc_count-1) {		numblocks = (fs->super->s_blocks_count -			     fs->super->s_first_data_block) %			fs->super->s_blocks_per_group;		if (!numblocks)			numblocks = fs->super->s_blocks_per_group;	} else		numblocks = fs->super->s_blocks_per_group;	has_super = ext2fs_bg_has_super(fs, group);	if (has_super) {		super_blk = group_block;		numblocks--;	}	meta_bg_size = (fs->blocksize / sizeof (struct ext2_group_desc));	meta_bg = group / meta_bg_size;	if (!(fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG) ||	    (meta_bg < fs->super->s_first_meta_bg)) {		if (has_super) {			old_desc_blk = group_block + 1;			numblocks -= old_desc_blocks;		}	} else {		if (((group % meta_bg_size) == 0) ||		    ((group % meta_bg_size) == 1) ||		    ((group % meta_bg_size) == (meta_bg_size-1))) {			if (has_super)				has_super = 1;			new_desc_blk = group_block + has_super;			numblocks--;		}	}	numblocks -= 2 + fs->inode_blocks_per_group;	if (ret_super_blk)		*ret_super_blk = super_blk;	if (ret_old_desc_blk)		*ret_old_desc_blk = old_desc_blk;	if (ret_new_desc_blk)		*ret_new_desc_blk = new_desc_blk;	if (ret_meta_bg)		*ret_meta_bg = meta_bg;	return numblocks;}/* * This function forces out the primary superblock.  We need to only * write out those fields which we have changed, since if the * filesystem is mounted, it may have changed some of the other * fields. * * It takes as input a superblock which has already been byte swapped * (if necessary). * */static errcode_t write_primary_superblock(ext2_filsys fs,					  struct ext2_super_block *super){	__u16		*old_super, *new_super;	int		check_idx, write_idx, size;	errcode_t	retval;	if (!fs->io->manager->write_byte || !fs->orig_super) {		io_channel_set_blksize(fs->io, SUPERBLOCK_OFFSET);		retval = io_channel_write_blk(fs->io, 1, -SUPERBLOCK_SIZE,					      super);		io_channel_set_blksize(fs->io, fs->blocksize);		return retval;	}	old_super = (__u16 *) fs->orig_super;	new_super = (__u16 *) super;	for (check_idx = 0; check_idx < SUPERBLOCK_SIZE/2; check_idx++) {		if (old_super[check_idx] == new_super[check_idx])			continue;		write_idx = check_idx;		for (check_idx++; check_idx < SUPERBLOCK_SIZE/2; check_idx++)			if (old_super[check_idx] == new_super[check_idx])				break;		size = 2 * (check_idx - write_idx);		retval = io_channel_write_byte(fs->io,			       SUPERBLOCK_OFFSET + (2 * write_idx), size,					       new_super + write_idx);		if (retval)			return retval;	}	memcpy(fs->orig_super, super, SUPERBLOCK_SIZE);	return 0;}/* * Updates the revision to EXT2_DYNAMIC_REV */void ext2fs_update_dynamic_rev(ext2_filsys fs){	struct ext2_super_block *sb = fs->super;	if (sb->s_rev_level > EXT2_GOOD_OLD_REV)		return;	sb->s_rev_level = EXT2_DYNAMIC_REV;	sb->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;	sb->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;	/* s_uuid is handled by e2fsck already */	/* other fields should be left alone */}static errcode_t write_backup_super(ext2_filsys fs, dgrp_t group,				    blk_t group_block,				    struct ext2_super_block *super_shadow){	dgrp_t	sgrp = group;	if (sgrp > ((1 << 16) - 1))		sgrp = (1 << 16) - 1;#if BB_BIG_ENDIAN	if (fs->flags & EXT2_FLAG_SWAP_BYTES)		super_shadow->s_block_group_nr = ext2fs_swab16(sgrp);	else#endif		fs->super->s_block_group_nr = sgrp;	return io_channel_write_blk(fs->io, group_block, -SUPERBLOCK_SIZE,				    super_shadow);}errcode_t ext2fs_flush(ext2_filsys fs){	dgrp_t		i;	blk_t		group_block;	errcode_t	retval;	unsigned long	fs_state;	struct ext2_super_block *super_shadow = 0;	struct ext2_group_desc *group_shadow = 0;	char	*group_ptr;	int	old_desc_blocks;#if BB_BIG_ENDIAN	dgrp_t		j;	struct ext2_group_desc *s, *t;#endif	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);	fs_state = fs->super->s_state;	fs->super->s_wtime = time(NULL);	fs->super->s_block_group_nr = 0;#if BB_BIG_ENDIAN	if (fs->flags & EXT2_FLAG_SWAP_BYTES) {		retval = EXT2_ET_NO_MEMORY;		retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &super_shadow);		if (retval)			goto errout;		retval = ext2fs_get_mem((size_t)(fs->blocksize *						 fs->desc_blocks),					&group_shadow);		if (retval)			goto errout;		memset(group_shadow, 0, (size_t) fs->blocksize *		       fs->desc_blocks);		/* swap the group descriptors */		for (j=0, s=fs->group_desc, t=group_shadow;		     j < fs->group_desc_count; j++, t++, s++) {			*t = *s;			ext2fs_swap_group_desc(t);		}	} else {		super_shadow = fs->super;		group_shadow = fs->group_desc;	}#else	super_shadow = fs->super;	group_shadow = fs->group_desc;#endif	/*	 * If this is an external journal device, don't write out the	 * block group descriptors or any of the backup superblocks	 */	if (fs->super->s_feature_incompat &	    EXT3_FEATURE_INCOMPAT_JOURNAL_DEV)		goto write_primary_superblock_only;	/*	 * Set the state of the FS to be non-valid.  (The state has	 * already been backed up earlier, and will be restored after	 * we write out the backup superblocks.)	 */	fs->super->s_state &= ~EXT2_VALID_FS;#if BB_BIG_ENDIAN	if (fs->flags & EXT2_FLAG_SWAP_BYTES) {		*super_shadow = *fs->super;		ext2fs_swap_super(super_shadow);	}#endif	/*	 * Write out the master group descriptors, and the backup	 * superblocks and group descriptors.	 */	group_block = fs->super->s_first_data_block;	group_ptr = (char *) group_shadow;	if (fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG)		old_desc_blocks = fs->super->s_first_meta_bg;	else		old_desc_blocks = fs->desc_blocks;	for (i = 0; i < fs->group_desc_count; i++) {		blk_t	super_blk, old_desc_blk, new_desc_blk;		int	meta_bg;		ext2fs_super_and_bgd_loc(fs, i, &super_blk, &old_desc_blk,					 &new_desc_blk, &meta_bg);		if (!(fs->flags & EXT2_FLAG_MASTER_SB_ONLY) &&i && super_blk) {			retval = write_backup_super(fs, i, super_blk,						    super_shadow);			if (retval)				goto errout;		}		if (fs->flags & EXT2_FLAG_SUPER_ONLY)			continue;		if ((old_desc_blk) &&		    (!(fs->flags & EXT2_FLAG_MASTER_SB_ONLY) || (i == 0))) {			retval = io_channel_write_blk(fs->io,			      old_desc_blk, old_desc_blocks, group_ptr);			if (retval)				goto errout;		}		if (new_desc_blk) {			retval = io_channel_write_blk(fs->io, new_desc_blk,				1, group_ptr + (meta_bg*fs->blocksize));			if (retval)				goto errout;		}	}	fs->super->s_block_group_nr = 0;	fs->super->s_state = fs_state;#if BB_BIG_ENDIAN	if (fs->flags & EXT2_FLAG_SWAP_BYTES) {		*super_shadow = *fs->super;		ext2fs_swap_super(super_shadow);	}#endif	/*	 * If the write_bitmaps() function is present, call it to	 * flush the bitmaps.  This is done this way so that a simple	 * program that doesn't mess with the bitmaps doesn't need to	 * drag in the bitmaps.c code.	 */	if (fs->write_bitmaps) {		retval = fs->write_bitmaps(fs);		if (retval)			goto errout;	}write_primary_superblock_only:	/*	 * Write out master superblock.  This has to be done	 * separately, since it is located at a fixed location	 * (SUPERBLOCK_OFFSET).  We flush all other pending changes	 * out to disk first, just to avoid a race condition with an	 * insy-tinsy window....	 */	retval = io_channel_flush(fs->io);	retval = write_primary_superblock(fs, super_shadow);	if (retval)		goto errout;	fs->flags &= ~EXT2_FLAG_DIRTY;	retval = io_channel_flush(fs->io);errout:	fs->super->s_state = fs_state;	if (fs->flags & EXT2_FLAG_SWAP_BYTES) {		if (super_shadow)			ext2fs_free_mem(&super_shadow);		if (group_shadow)			ext2fs_free_mem(&group_shadow);	}	return retval;}errcode_t ext2fs_close(ext2_filsys fs){	errcode_t	retval;	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);	if (fs->flags & EXT2_FLAG_DIRTY) {		retval = ext2fs_flush(fs);		if (retval)			return retval;	}	if (fs->write_bitmaps) {		retval = fs->write_bitmaps(fs);		if (retval)			return retval;	}	ext2fs_free(fs);	return 0;}