parted-1.8.7/libparted/fs/ext2/ext2.c - nest-learning-thermostat/5.1.1/parted - Git at Google

 /*
     ext2.c -- generic ext2 stuff
     Copyright (C) 1998, 1999, 2000, 2001, 2007 Free Software Foundation, Inc.

     This program is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
     the Free Software Foundation; either version 2 of the License, or
     (at your option) any later version.

     This program is distributed in the hope that it will be useful,
     but WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     GNU General Public License for more details.

     You should have received a copy of the GNU General Public License
     along with this program; if not, write to the Free Software
     Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
 */

 #include <config.h>

 #ifndef DISCOVER_ONLY

 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <time.h>
 #include <uuid/uuid.h>
 #include "ext2.h"

 /* ext2 stuff ****************************************************************/

 unsigned char _bitmap[8] = {0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80};

 int ext2_copy_block(struct ext2_fs *fs, blk_t from, blk_t to)
 {
 	unsigned char* buf = ped_malloc (fs->blocksize);

 	if (!ext2_bcache_flush(fs, from)) return 0;
 	if (!ext2_bcache_flush(fs, to)) return 0;

 	if (!ext2_read_blocks(fs, buf, from, 1)) return 0;
 	if (!ext2_write_blocks(fs, buf, to, 1)) return 0;

 	return 1;
 }

 int ext2_get_block_state(struct ext2_fs *fs, blk_t block)
 {
 	struct ext2_buffer_head *bh;
 	int group;
 	int offset;
 	int state;

 	block -= EXT2_SUPER_FIRST_DATA_BLOCK(fs->sb);
 	group = block / EXT2_SUPER_BLOCKS_PER_GROUP(fs->sb);
 	offset = block % EXT2_SUPER_BLOCKS_PER_GROUP(fs->sb);

 	bh = ext2_bread(fs, EXT2_GROUP_BLOCK_BITMAP(fs->gd[group]));
 	state = bh->data[offset>>3] & _bitmap[offset&7];
 	ext2_brelse(bh, 0);

 	return state;
 }

 blk_t ext2_find_free_block(struct ext2_fs *fs)
 {
 	int i;

 	for (i=0;i<fs->numgroups;i++)
 		if (EXT2_GROUP_FREE_BLOCKS_COUNT(fs->gd[i]))
 		{
 			blk_t j;
 			blk_t offset;

 			offset = i * EXT2_SUPER_BLOCKS_PER_GROUP(fs->sb)
 				 + EXT2_SUPER_FIRST_DATA_BLOCK(fs->sb);
 			for (j=fs->adminblocks;
 			     j<EXT2_SUPER_BLOCKS_PER_GROUP(fs->sb);
 			     j++)
 				if (ext2_is_data_block(fs, offset + j) &&
 				    !ext2_get_block_state(fs, offset + j))
 					return offset + j;

 			ped_exception_throw (PED_EXCEPTION_ERROR,
 				PED_EXCEPTION_CANCEL,
 				_("Inconsistent group descriptors!"));
 		}

 	ped_exception_throw (PED_EXCEPTION_ERROR, PED_EXCEPTION_CANCEL,
 			     _("File system full!"));
 	return 0;
 }

 ino_t ext2_find_free_inode(struct ext2_fs *fs)
 {
 	int i;

 	for (i=0;i<fs->numgroups;i++)
 		if (EXT2_GROUP_FREE_INODES_COUNT(fs->gd[i]))
 		{
 			ino_t j;
 			ino_t offset;

 			offset = i * EXT2_SUPER_INODES_PER_GROUP(fs->sb) + 1;
 			for (j=0;j<EXT2_SUPER_INODES_PER_GROUP(fs->sb);j++)
 				if (!ext2_get_inode_state(fs, offset + j))
 					return offset + j;

 			ped_exception_throw (PED_EXCEPTION_ERROR,
 				PED_EXCEPTION_CANCEL,
 				_("Inconsistent group descriptors!"));
 		}

 	ped_exception_throw (PED_EXCEPTION_ERROR, PED_EXCEPTION_CANCEL,
 			     _("File system full!"));
 	return 0;
 }

 int ext2_move_blocks(struct ext2_fs *fs, blk_t src, blk_t num, blk_t dest)
 {
 	unsigned char *buf;
 	blk_t i;

 	ped_exception_fetch_all();
 	if ((buf = ped_malloc(num << fs->logsize)) != NULL)
 	{
 		ped_exception_leave_all();

 		if (!ext2_bcache_flush_range(fs, src, num)) return 0;
 		if (!ext2_bcache_flush_range(fs, dest, num)) return 0;

 		if (!ext2_read_blocks(fs, buf, src, num)) return 0;
 		if (!ext2_write_blocks(fs, buf, dest, num)) return 0;

 		ped_free(buf);
 		return 1;
 	}
 	ped_exception_catch();
 	ped_exception_leave_all();

 	if (src > dest)
 	{
 		for (i=0;i<num;i++)
 			if (!ext2_copy_block(fs, src+i, dest+i))
 				return 0;
 	}
 	else
 	{
 		for (i=num;i>0;i--)
 			if (!ext2_copy_block(fs, src+i, dest+i))
 				return 0;
 	}
 	return 1;
 }

 int ext2_read_blocks(struct ext2_fs *fs, void *ptr, blk_t block, blk_t num)
 {
 	return fs->devhandle->ops->read(fs->devhandle->cookie, ptr, block, num);
 }

 int ext2_set_block_state(struct ext2_fs *fs, blk_t block, int state, int updatemetadata)
 {
 	struct ext2_buffer_head *bh;
 	int                      group;
 	int                      offset;

 	block -= EXT2_SUPER_FIRST_DATA_BLOCK(fs->sb);
 	group = block / EXT2_SUPER_BLOCKS_PER_GROUP(fs->sb);
 	offset = block % EXT2_SUPER_BLOCKS_PER_GROUP(fs->sb);

 	bh = ext2_bread(fs, EXT2_GROUP_BLOCK_BITMAP(fs->gd[group]));
 	bh->dirty = 1;
 	if (state)
 		bh->data[offset>>3] |= _bitmap[offset&7];
 	else
 		bh->data[offset>>3] &= ~_bitmap[offset&7];
 	ext2_brelse(bh, 0);

 	if (updatemetadata)
 	{
 		int diff;

 		diff = state ? -1 : 1;

 		fs->gd[group].bg_free_blocks_count = PED_CPU_TO_LE16
 			(EXT2_GROUP_FREE_BLOCKS_COUNT(fs->gd[group]) + diff);
 		fs->sb.s_free_blocks_count = PED_CPU_TO_LE32
 			(EXT2_SUPER_FREE_BLOCKS_COUNT(fs->sb) + diff);
 		fs->metadirty |= EXT2_META_SB | EXT2_META_GD;
 	}
 	return 1;
 }

 int ext2_write_blocks(struct ext2_fs *fs, void *ptr, blk_t block, blk_t num)
 {
 	return fs->devhandle->ops->write(fs->devhandle->cookie, ptr, block, num);
 }

 int ext2_zero_blocks(struct ext2_fs *fs, blk_t block, blk_t num)
 {
 	unsigned char *buf;
 	blk_t i;

 	ped_exception_fetch_all();
 	buf = ped_malloc (num << fs->logsize);
 	if (buf)
 	{
 		ped_exception_leave_all();

 		memset(buf, 0, num << fs->logsize);
 		if (!ext2_bcache_flush_range(fs, block, num))
 			goto error_free_buf;
 		if (!ext2_write_blocks(fs, buf, block, num))
 			goto error_free_buf;
 		ped_free(buf);
 		return 1;
 	}
 	ped_exception_catch();

 	buf = ped_malloc (fs->blocksize);
 	if (buf)
 	{
 		ped_exception_leave_all();

 		memset(buf, 0, fs->blocksize);

 		for (i=0;i<num;i++)
 		{
 			if (!ext2_bcache_flush(fs, block+i))
 				goto error_free_buf;
 			if (!ext2_write_blocks(fs, buf, block+i, 1))
 				goto error_free_buf;
 		}

 		ped_free(buf);
 		return 1;
 	}
 	ped_exception_catch();
 	ped_exception_leave_all();

 	for (i=0;i<num;i++)
 	{
 		struct ext2_buffer_head *bh;

 		bh = ext2_bcreate(fs, block+i);
 		if (!bh)
 			goto error;
 		bh->dirty = 1;
 		if (!ext2_brelse(bh, 1))
 			goto error;
 	}
 	return 1;

 error_free_buf:
 	ped_free(buf);
 error:
 	return 0;
 }

 off_t ext2_get_inode_offset(struct ext2_fs *fs, ino_t inode, blk_t *block)
 {
 	int group;
 	int offset;

 	inode--;

 	group = inode / EXT2_SUPER_INODES_PER_GROUP(fs->sb);
 	offset = (inode % EXT2_SUPER_INODES_PER_GROUP(fs->sb))
 	       	 * sizeof(struct ext2_inode);

 	*block = EXT2_GROUP_INODE_TABLE(fs->gd[group])
 	         + (offset >> fs->logsize);

 	return offset & (fs->blocksize - 1);
 }

 int ext2_get_inode_state(struct ext2_fs *fs, ino_t inode)
 {
 	struct ext2_buffer_head *bh;
 	int                      group;
 	int                      offset;
 	int                      ret;

 	inode--;
 	group = inode / EXT2_SUPER_INODES_PER_GROUP(fs->sb);
 	offset = inode % EXT2_SUPER_INODES_PER_GROUP(fs->sb);

 	bh = ext2_bread(fs, EXT2_GROUP_INODE_BITMAP(fs->gd[group]));
 	ret = bh->data[offset>>3] & _bitmap[offset&7];
 	ext2_brelse(bh, 0);

 	return ret;
 }

 int ext2_read_inode(struct ext2_fs *fs, ino_t inode, struct ext2_inode *data)
 {
 	struct ext2_buffer_head *bh;
 	blk_t			 blk;
 	off_t			 off;

 	off = ext2_get_inode_offset(fs, inode, &blk);

 	bh = ext2_bread(fs, blk);
 	if (!bh)
 		return 0;

 	memcpy(data, bh->data + off, sizeof(struct ext2_inode));
 	ext2_brelse(bh, 0);
 	return 1;
 }

 int ext2_set_inode_state(struct ext2_fs *fs, ino_t inode, int state, int updatemetadata)
 {
 	struct ext2_buffer_head *bh;
 	int                      group;
 	int                      offset;

 	inode--;
 	group = inode / EXT2_SUPER_INODES_PER_GROUP(fs->sb);
 	offset = inode % EXT2_SUPER_INODES_PER_GROUP(fs->sb);

 	bh = ext2_bread(fs, EXT2_GROUP_INODE_BITMAP(fs->gd[group]));
 	if (!bh)
 		return 0;
 	bh->dirty = 1;
 	if (state)
 		bh->data[offset>>3] |= _bitmap[offset&7];
 	else
 		bh->data[offset>>3] &= ~_bitmap[offset&7];
 	ext2_brelse(bh, 0);

 	if (updatemetadata)
 	{
 		int diff;

 		diff = state ? -1 : 1;

 		fs->gd[group].bg_free_inodes_count = PED_CPU_TO_LE16
 			(EXT2_GROUP_FREE_INODES_COUNT(fs->gd[group]) + diff);
 		fs->sb.s_free_inodes_count = PED_CPU_TO_LE32
 			(EXT2_SUPER_FREE_INODES_COUNT(fs->sb) + diff);
 		fs->metadirty = EXT2_META_SB | EXT2_META_GD;
 	}
 	return 1;
 }

 static void
 _inode_update_size(struct ext2_fs *fs, struct ext2_inode *inode, int delta)
 {
 	int		i512perblock = 1 << (fs->logsize - 9);
 	uint64_t	size;

 	/* i_blocks is in 512 byte blocks */
 	inode->i_blocks = PED_CPU_TO_LE32(EXT2_INODE_BLOCKS(*inode)
 		       			  + delta * i512perblock);
 	size = EXT2_INODE_SIZE(*inode) + delta * fs->blocksize;
 	inode->i_size = PED_CPU_TO_LE32(size % (1LL << 32));
 	inode->i_size_high = PED_CPU_TO_LE32(size / (1LL << 32));
 	inode->i_mtime = PED_CPU_TO_LE32(time(NULL));
 }

 int ext2_do_inode(struct ext2_fs *fs, struct ext2_inode *inode, blk_t block,
 		   int action)
 {
 	struct ext2_buffer_head *bh;
 	uint32_t		*udata;
 	blk_t			 count = 0;
 	int			 i;
 	int			 u32perblock = fs->blocksize >> 2;
 	int			 i512perblock = 1 << (fs->logsize - 9);

 	if (block == 0 || EXT2_INODE_MODE(*inode) == 0)
 		return -1;

 	if (fs->opt_debug)
 		switch (action)
 		{
 			case EXT2_ACTION_ADD:
 				fprintf(stderr,"adding 0x%04x to inode\n",
 					block);
 				break;
 			case EXT2_ACTION_DELETE:
 				fprintf(stderr,"deleting 0x%04x from inode\n",
 					block);
 				break;
 			case EXT2_ACTION_FIND:
 				fprintf(stderr,"finding 0x%04x in inode\n",
 					block);
 				break;
 		}

 	/* Direct blocks for first 12 blocks */
 	for (i = 0; i < EXT2_NDIR_BLOCKS; i++)
 	{
 		if (action == EXT2_ACTION_ADD && !EXT2_INODE_BLOCK(*inode, i))
 		{
 			inode->i_block[i] = PED_CPU_TO_LE32(block);
 			_inode_update_size (fs, inode, 1);
 			ext2_set_block_state(fs, block, 1, 1);
 			return i;
 		}
 		if (EXT2_INODE_BLOCK(*inode, i) == block)
 		{
 			if (action == EXT2_ACTION_DELETE)
 			{
 				inode->i_block[i] = 0;
 				_inode_update_size (fs, inode, -1);
 				ext2_set_block_state(fs, block, 0, 1);
 			}
 			return i;
 		}
 		if (EXT2_INODE_BLOCK(*inode, i))
 			count += i512perblock;
 	}

 	count += EXT2_INODE_BLOCK(*inode, EXT2_IND_BLOCK) ? i512perblock : 0;
 	count += EXT2_INODE_BLOCK(*inode, EXT2_DIND_BLOCK) ? i512perblock : 0;
 	count += EXT2_INODE_BLOCK(*inode, EXT2_TIND_BLOCK) ? i512perblock : 0;

 	if (!EXT2_INODE_BLOCK(*inode, EXT2_IND_BLOCK) ||
 	    (count >= EXT2_INODE_BLOCKS(*inode) && action != EXT2_ACTION_ADD))
 		return -1;

 	bh = ext2_bread(fs, EXT2_INODE_BLOCK(*inode, EXT2_IND_BLOCK));
 	udata = (uint32_t *)bh->data;

 	/* Indirect blocks for next 256/512/1024 blocks (for 1k/2k/4k blocks) */
 	for (i = 0; i < u32perblock; i++) {
 		if (action == EXT2_ACTION_ADD && !udata[i]) {
 			bh->dirty = 1;
 			udata[i] = PED_CPU_TO_LE32(block);
 			_inode_update_size (fs, inode, 1);
 			ext2_set_block_state(fs, block, 1, 1);
 			ext2_brelse(bh, 0);
 			return EXT2_NDIR_BLOCKS + i;
 		}
 		if (PED_LE32_TO_CPU(udata[i]) == block) {
 			if (action == EXT2_ACTION_DELETE) {
 				bh->dirty = 1;
 				udata[i] = 0;
 				_inode_update_size (fs, inode, -1);
 				ext2_set_block_state(fs, block, 0, 1);
 			}
 			ext2_brelse(bh, 0);
 			return EXT2_NDIR_BLOCKS + i;
 		}
 		if (udata[i])
 		{
 			count += i512perblock;
 			if (count >= EXT2_INODE_BLOCKS(*inode) &&
 			    action != EXT2_ACTION_ADD)
 				return -1;
 		}
 	}

 	ext2_brelse(bh, 0);

 	if (!EXT2_INODE_BLOCK(*inode, EXT2_DIND_BLOCK) ||
 	    (count >= EXT2_INODE_BLOCKS(*inode) && action != EXT2_ACTION_ADD))
 		return -1;
 	bh = ext2_bread(fs, EXT2_INODE_BLOCK(*inode, EXT2_DIND_BLOCK));
 	udata = (uint32_t *)bh->data;

 	/* Double indirect blocks for next 2^16/2^18/2^20 1k/2k/4k blocks */
 	for (i = 0; i < u32perblock; i++) {
 		struct ext2_buffer_head	*bh2;
 		uint32_t			*udata2;
 		int			 j;

 		if (!udata[i]) {
 			ext2_brelse(bh, 0);
 			return -1;
 		}
 		bh2 = ext2_bread(fs, PED_LE32_TO_CPU(udata[i]));
 		udata2 = (uint32_t *)bh2->data;
 		count += i512perblock;

 		for (j = 0; j < u32perblock; j++) {
 			if (action == EXT2_ACTION_ADD && !udata2[j]) {
 				bh2->dirty = 1;
 				udata2[j] = PED_CPU_TO_LE32(block);
 				_inode_update_size (fs, inode, 1);
 				ext2_set_block_state(fs, block, 1, 1);
 				ext2_brelse(bh, 0);
 				ext2_brelse(bh2, 0);
 				return EXT2_NDIR_BLOCKS + i * u32perblock + j;
 			}
 			if (PED_LE32_TO_CPU(udata2[j]) == block) {
 				if (action == EXT2_ACTION_DELETE) {
 					bh2->dirty = 1;
 					udata2[j] = 0;
 					_inode_update_size (fs, inode, -1);
 					ext2_set_block_state(fs, block, 0, 1);
 				}
 				ext2_brelse(bh, 0);
 				ext2_brelse(bh2, 0);
 				return EXT2_NDIR_BLOCKS + i * u32perblock + j;
 			}
 			if (udata2[j])
 			{
 				count += i512perblock;
 				if (count >= EXT2_INODE_BLOCKS(*inode) &&
 				    action != EXT2_ACTION_ADD)
 					return -1;
 			}
 		}
 		ext2_brelse(bh2, 0);
 	}
 	ext2_brelse(bh, 0);

 	/* FIXME: we should check for triple-indirect blocks here, but it
 	 * would be nice to have a better routine to traverse blocks, and
 	 * file systems that need triple-indirect blocks for the resize
 	 * inode are too big to worry about yet.
 	 */

 	return -1;
 }

 int ext2_write_inode(struct ext2_fs *fs, ino_t inode, const struct ext2_inode *data)
 {
 	struct ext2_buffer_head *bh;
 	blk_t			 blk;
 	off_t			 off;

 	off = ext2_get_inode_offset(fs, inode, &blk);

 	bh = ext2_bread(fs, blk);
 	if (!bh)
 		return 0;
 	bh->dirty = 1;
 	memcpy(bh->data + off, data, sizeof(struct ext2_inode));
 	ext2_brelse(bh, 0);

 	return 1;
 }

 int ext2_zero_inode(struct ext2_fs *fs, ino_t inode)
 {
 	struct ext2_inode buf;

 	memset(&buf, 0, sizeof(struct ext2_inode));
 	return ext2_write_inode(fs, inode, &buf);
 }


 /* check whether y is root of x
  * (formula grabbed from linux ext2 kernel source) */
 static int is_root(int x, int y)
 {
 	if (!x)
 		return 1;

 	while (1)
 	{
 		if (x == 1)
 			return 1;

 		if (x % y)
 			return 0;

 		x /= y;
 	}
 }

 /* check whether group contains a superblock copy on file systems
  * where not all groups have one (sparse superblock feature) */
 int ext2_is_group_sparse(struct ext2_fs *fs, int group)
 {
 	if (!fs->sparse)
 		return 1;

 	if (is_root(group, 3) || is_root(group, 5) || is_root(group, 7))
 		return 1;

 	return 0;
 }

 void ext2_close(struct ext2_fs *fs)
 {
 	ext2_commit_metadata(fs, EXT2_META_PRIMARY | EXT2_META_BACKUP);
 	ext2_sync(fs);

 	ext2_bcache_deinit(fs);

 	fs->devhandle->ops->close(fs->devhandle->cookie);

 	ped_free(fs->gd);
 	ped_free(fs);
 }

 int ext2_commit_metadata(struct ext2_fs *fs, int copies)
 {
 	int		i;
 	int		num;
 	int		wmeta = fs->metadirty & copies;
 	unsigned char*	sb = ped_malloc(fs->blocksize);
 	struct ext2_super_block *sb_for_io;
 	int		sb_block;

 	/* See if there is even anything to write... */
 	if (wmeta == EXT2_META_CLEAN)
 		return 1;

 	fs->sb.s_r_blocks_count = PED_CPU_TO_LE32 (
 		fs->r_frac * (loff_t)EXT2_SUPER_BLOCKS_COUNT(fs->sb)
 				  / 100);

 	if (!ext2_read_blocks (fs, sb, 0, 1))
 		return 0;

 	if (EXT2_SUPER_FIRST_DATA_BLOCK(fs->sb)) {
 		memcpy(sb, &fs->sb, 1024);
 		sb_for_io = (struct ext2_super_block *) sb;
 	} else {
 		memcpy(sb+1024, &fs->sb, 1024);
 		sb_for_io = (struct ext2_super_block *) (sb + 1024);
 	}

 	num = copies & EXT2_META_BACKUP ? fs->numgroups : 1;

 	for (i = 0, sb_block = EXT2_SUPER_FIRST_DATA_BLOCK(fs->sb); i < num;
 	     i++, sb_block += EXT2_SUPER_BLOCKS_PER_GROUP(fs->sb))
 	{

 		if (!ext2_is_group_sparse(fs, i))
 			continue;

 		if (fs->dynamic_version)
 			sb_for_io->s_block_group_nr = PED_CPU_TO_LE16 (i);

 		if ((i == 0 && wmeta & EXT2_META_PRIMARY_SB) ||
 		    (i != 0 && wmeta & EXT2_META_SB))
 		{
 			if (!ext2_bcache_flush_range(fs, sb_block, 1))
 				return 0;
 			if (!ext2_write_blocks(fs, sb, sb_block, 1))
 				return 0;
 		}
 		if ((i == 0 && wmeta & EXT2_META_PRIMARY_GD) ||
 		    (i != 0 && wmeta & EXT2_META_GD))
 		{
 			if (!ext2_bcache_flush_range(fs, sb_block + 1,
 						     fs->gdblocks))
 				return 0;
 			if (!ext2_write_blocks(fs, fs->gd, sb_block + 1,
 					       fs->gdblocks))
 				return 0;
 		}
 	}

 	sb_for_io->s_block_group_nr = 0;

 	/* Clear the flags of the components we just finished writing. */
 	fs->metadirty &= ~copies;

 	return 1;
 }

 int ext2_sync(struct ext2_fs *fs)
 {
 	if (!ext2_commit_metadata(fs, EXT2_META_PRIMARY)) return 0;
 	if (!ext2_bcache_sync(fs)) return 0;
 	if (!fs->devhandle->ops->sync(fs->devhandle->cookie)) return 0;
 	return 1;
 }

 struct ext2_fs *ext2_open(struct ext2_dev_handle *handle, int state)
 {
 	struct ext2_fs *fs;

 	if ((fs = (struct ext2_fs *) ped_malloc(sizeof(struct ext2_fs)))
 		== NULL)
 		goto error;

 	handle->ops->set_blocksize(handle->cookie, 10);

 	if (!handle->ops->read(handle->cookie, &fs->sb, 1, 1)
 	    || EXT2_SUPER_MAGIC(fs->sb) != EXT2_SUPER_MAGIC_CONST)
 	{
 		ped_exception_throw (PED_EXCEPTION_ERROR, PED_EXCEPTION_CANCEL,
 			_("Invalid superblock.  Are you sure this is an ext2 "
 			  "file system?"));
 		goto error_free_fs;
 	}


 	fs->opt_debug = 1;
 	fs->opt_safe = 1;
 	fs->opt_verbose = 0;

 	if (EXT2_SUPER_STATE(fs->sb) & EXT2_ERROR_FS & ~(state & EXT2_ERROR_FS))
 	{
 		if (ped_exception_throw (
 			PED_EXCEPTION_WARNING, PED_EXCEPTION_IGNORE_CANCEL,
 			_("File system has errors!  You should run e2fsck."))
 				== PED_EXCEPTION_CANCEL)
 			goto error_free_fs;
 	}

 	if (!((EXT2_SUPER_STATE(fs->sb) | state) & EXT2_VALID_FS)
 	    || (EXT2_SUPER_FEATURE_INCOMPAT(fs->sb)
 		& EXT3_FEATURE_INCOMPAT_RECOVER))
 	{
 		if (ped_exception_throw (
 			PED_EXCEPTION_ERROR, PED_EXCEPTION_IGNORE_CANCEL,
 			_("File system was not cleanly unmounted!  "
 			  "You should run e2fsck.  Modifying an unclean "
 			  "file system could cause severe corruption."))
 				!= PED_EXCEPTION_IGNORE)
 			goto error_free_fs;
 	}

 	fs->dynamic_version = EXT2_SUPER_REV_LEVEL (fs->sb) > 0;

 	if ((EXT2_SUPER_FEATURE_COMPAT(fs->sb)
 	                & ~(EXT3_FEATURE_COMPAT_HAS_JOURNAL |
 			    EXT2_FEATURE_COMPAT_HAS_DIR_INDEX)) ||
 	    (EXT2_SUPER_FEATURE_INCOMPAT(fs->sb)
 	    		& ~(EXT2_FEATURE_INCOMPAT_FILETYPE |
 			    EXT3_FEATURE_INCOMPAT_RECOVER)) ||
 	    (EXT2_SUPER_FEATURE_RO_COMPAT(fs->sb)
 			& ~(EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER |
 			    EXT2_FEATURE_RO_COMPAT_LARGE_FILE)))
 	{
 		ped_exception_throw (PED_EXCEPTION_ERROR, PED_EXCEPTION_CANCEL,
 		     _("File system has an incompatible feature enabled."));
 		goto error_free_fs;
 	}

 	fs->devhandle = handle;
 	fs->logsize = EXT2_SUPER_LOG_BLOCK_SIZE(fs->sb) + 10;
 	handle->ops->set_blocksize(handle->cookie, fs->logsize);

 	if (!ext2_bcache_init(fs))
 	{
 		ped_exception_throw (PED_EXCEPTION_ERROR, PED_EXCEPTION_CANCEL,
 				     _("Error allocating buffer cache."));
 		goto error_free_fs;
 	}

 	fs->blocksize = 1 << fs->logsize;

 	fs->numgroups = ped_div_round_up (EXT2_SUPER_BLOCKS_COUNT(fs->sb)
 		       		- EXT2_SUPER_FIRST_DATA_BLOCK(fs->sb),
 				EXT2_SUPER_BLOCKS_PER_GROUP(fs->sb));
 	fs->gdblocks = ped_div_round_up (fs->numgroups
                         * sizeof(struct ext2_group_desc),
 			       fs->blocksize);
 	fs->inodeblocks = ped_div_round_up (EXT2_SUPER_INODES_PER_GROUP(fs->sb)
 		       		  * sizeof(struct ext2_inode),
 				  fs->blocksize);
 	fs->r_frac = ped_div_round_up (100 * (loff_t)EXT2_SUPER_R_BLOCKS_COUNT(fs->sb),
 		       	     EXT2_SUPER_BLOCKS_COUNT(fs->sb));
 	fs->adminblocks = 3 + fs->gdblocks + fs->inodeblocks;

 	fs->sparse = 0;
 	if (EXT2_SUPER_FEATURE_RO_COMPAT(fs->sb)
 			& EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER)
 		fs->sparse = 1;

 	fs->has_journal = 0 < (EXT2_SUPER_FEATURE_COMPAT(fs->sb)
 			       & EXT3_FEATURE_COMPAT_HAS_JOURNAL);
 	fs->has_internal_journal
 		= fs->has_journal
 			&& uuid_is_null(EXT2_SUPER_JOURNAL_UUID(fs->sb))
 			&& EXT2_SUPER_JOURNAL_INUM(fs->sb);

 	fs->gd = ped_malloc (fs->numgroups * sizeof (struct ext2_group_desc)
 			     	+ fs->blocksize);
 	if (!fs->gd)
 		goto error_deinit_bcache;

 	ext2_read_blocks(fs, fs->gd, EXT2_SUPER_FIRST_DATA_BLOCK(fs->sb) + 1,
 			 fs->gdblocks);

 	fs->metadirty = 0;
 	return fs;

 	ped_free(fs->gd);
 error_deinit_bcache:
 	ext2_bcache_deinit(fs);
 error_free_fs:
 	ped_free(fs);
 error:
 	return NULL;
 }

 #endif /* !DISCOVER_ONLY */
	/*
	ext2.c -- generic ext2 stuff
	Copyright (C) 1998, 1999, 2000, 2001, 2007 Free Software Foundation, Inc.

	This program is free software; you can redistribute it and/or modify
	it under the terms of the GNU General Public License as published by
	the Free Software Foundation; either version 2 of the License, or
	(at your option) any later version.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with this program; if not, write to the Free Software
	Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
	*/

	#include <config.h>

	#ifndef DISCOVER_ONLY

	#include <stdio.h>
	#include <stdlib.h>
	#include <string.h>
	#include <time.h>
	#include <uuid/uuid.h>
	#include "ext2.h"

	/* ext2 stuff ****************************************************************/

	unsigned char _bitmap[8] = {0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80};

	int ext2_copy_block(struct ext2_fs *fs, blk_t from, blk_t to)
	{
	unsigned char* buf = ped_malloc (fs->blocksize);

	if (!ext2_bcache_flush(fs, from)) return 0;
	if (!ext2_bcache_flush(fs, to)) return 0;

	if (!ext2_read_blocks(fs, buf, from, 1)) return 0;
	if (!ext2_write_blocks(fs, buf, to, 1)) return 0;

	return 1;
	}

	int ext2_get_block_state(struct ext2_fs *fs, blk_t block)
	{
	struct ext2_buffer_head *bh;
	int group;
	int offset;
	int state;

	block -= EXT2_SUPER_FIRST_DATA_BLOCK(fs->sb);
	group = block / EXT2_SUPER_BLOCKS_PER_GROUP(fs->sb);
	offset = block % EXT2_SUPER_BLOCKS_PER_GROUP(fs->sb);

	bh = ext2_bread(fs, EXT2_GROUP_BLOCK_BITMAP(fs->gd[group]));
	state = bh->data[offset>>3] & _bitmap[offset&7];
	ext2_brelse(bh, 0);

	return state;
	}

	blk_t ext2_find_free_block(struct ext2_fs *fs)
	{
	int i;

	for (i=0;i<fs->numgroups;i++)
	if (EXT2_GROUP_FREE_BLOCKS_COUNT(fs->gd[i]))
	{
	blk_t j;
	blk_t offset;

	offset = i * EXT2_SUPER_BLOCKS_PER_GROUP(fs->sb)
	+ EXT2_SUPER_FIRST_DATA_BLOCK(fs->sb);
	for (j=fs->adminblocks;
	j<EXT2_SUPER_BLOCKS_PER_GROUP(fs->sb);
	j++)
	if (ext2_is_data_block(fs, offset + j) &&
	!ext2_get_block_state(fs, offset + j))
	return offset + j;

	ped_exception_throw (PED_EXCEPTION_ERROR,
	PED_EXCEPTION_CANCEL,
	_("Inconsistent group descriptors!"));
	}

	ped_exception_throw (PED_EXCEPTION_ERROR, PED_EXCEPTION_CANCEL,
	_("File system full!"));
	return 0;
	}

	ino_t ext2_find_free_inode(struct ext2_fs *fs)
	{
	int i;

	for (i=0;i<fs->numgroups;i++)
	if (EXT2_GROUP_FREE_INODES_COUNT(fs->gd[i]))
	{
	ino_t j;
	ino_t offset;

	offset = i * EXT2_SUPER_INODES_PER_GROUP(fs->sb) + 1;
	for (j=0;j<EXT2_SUPER_INODES_PER_GROUP(fs->sb);j++)
	if (!ext2_get_inode_state(fs, offset + j))
	return offset + j;

	ped_exception_throw (PED_EXCEPTION_ERROR,
	PED_EXCEPTION_CANCEL,
	_("Inconsistent group descriptors!"));
	}

	ped_exception_throw (PED_EXCEPTION_ERROR, PED_EXCEPTION_CANCEL,
	_("File system full!"));
	return 0;
	}

	int ext2_move_blocks(struct ext2_fs *fs, blk_t src, blk_t num, blk_t dest)
	{
	unsigned char *buf;
	blk_t i;

	ped_exception_fetch_all();
	if ((buf = ped_malloc(num << fs->logsize)) != NULL)
	{
	ped_exception_leave_all();

	if (!ext2_bcache_flush_range(fs, src, num)) return 0;
	if (!ext2_bcache_flush_range(fs, dest, num)) return 0;

	if (!ext2_read_blocks(fs, buf, src, num)) return 0;
	if (!ext2_write_blocks(fs, buf, dest, num)) return 0;

	ped_free(buf);
	return 1;
	}
	ped_exception_catch();
	ped_exception_leave_all();

	if (src > dest)
	{
	for (i=0;i<num;i++)
	if (!ext2_copy_block(fs, src+i, dest+i))
	return 0;
	}
	else
	{
	for (i=num;i>0;i--)
	if (!ext2_copy_block(fs, src+i, dest+i))
	return 0;
	}
	return 1;
	}

	int ext2_read_blocks(struct ext2_fs fs, void ptr, blk_t block, blk_t num)
	{
	return fs->devhandle->ops->read(fs->devhandle->cookie, ptr, block, num);
	}

	int ext2_set_block_state(struct ext2_fs *fs, blk_t block, int state, int updatemetadata)
	{
	struct ext2_buffer_head *bh;
	int group;
	int offset;

	block -= EXT2_SUPER_FIRST_DATA_BLOCK(fs->sb);
	group = block / EXT2_SUPER_BLOCKS_PER_GROUP(fs->sb);
	offset = block % EXT2_SUPER_BLOCKS_PER_GROUP(fs->sb);

	bh = ext2_bread(fs, EXT2_GROUP_BLOCK_BITMAP(fs->gd[group]));
	bh->dirty = 1;
	if (state)
	bh->data[offset>>3] \|= _bitmap[offset&7];
	else
	bh->data[offset>>3] &= ~_bitmap[offset&7];
	ext2_brelse(bh, 0);

	if (updatemetadata)
	{
	int diff;

	diff = state ? -1 : 1;

	fs->gd[group].bg_free_blocks_count = PED_CPU_TO_LE16
	(EXT2_GROUP_FREE_BLOCKS_COUNT(fs->gd[group]) + diff);
	fs->sb.s_free_blocks_count = PED_CPU_TO_LE32
	(EXT2_SUPER_FREE_BLOCKS_COUNT(fs->sb) + diff);
	fs->metadirty \|= EXT2_META_SB \| EXT2_META_GD;
	}
	return 1;
	}

	int ext2_write_blocks(struct ext2_fs fs, void ptr, blk_t block, blk_t num)
	{
	return fs->devhandle->ops->write(fs->devhandle->cookie, ptr, block, num);
	}

	int ext2_zero_blocks(struct ext2_fs *fs, blk_t block, blk_t num)
	{
	unsigned char *buf;
	blk_t i;

	ped_exception_fetch_all();
	buf = ped_malloc (num << fs->logsize);
	if (buf)
	{
	ped_exception_leave_all();

	memset(buf, 0, num << fs->logsize);
	if (!ext2_bcache_flush_range(fs, block, num))
	goto error_free_buf;
	if (!ext2_write_blocks(fs, buf, block, num))
	goto error_free_buf;
	ped_free(buf);
	return 1;
	}
	ped_exception_catch();

	buf = ped_malloc (fs->blocksize);
	if (buf)
	{
	ped_exception_leave_all();

	memset(buf, 0, fs->blocksize);

	for (i=0;i<num;i++)
	{
	if (!ext2_bcache_flush(fs, block+i))
	goto error_free_buf;
	if (!ext2_write_blocks(fs, buf, block+i, 1))
	goto error_free_buf;
	}

	ped_free(buf);
	return 1;
	}
	ped_exception_catch();
	ped_exception_leave_all();

	for (i=0;i<num;i++)
	{
	struct ext2_buffer_head *bh;

	bh = ext2_bcreate(fs, block+i);
	if (!bh)
	goto error;
	bh->dirty = 1;
	if (!ext2_brelse(bh, 1))
	goto error;
	}
	return 1;

	error_free_buf:
	ped_free(buf);
	error:
	return 0;
	}

	off_t ext2_get_inode_offset(struct ext2_fs fs, ino_t inode, blk_t block)
	{
	int group;
	int offset;

	inode--;

	group = inode / EXT2_SUPER_INODES_PER_GROUP(fs->sb);
	offset = (inode % EXT2_SUPER_INODES_PER_GROUP(fs->sb))
	* sizeof(struct ext2_inode);

	*block = EXT2_GROUP_INODE_TABLE(fs->gd[group])
	+ (offset >> fs->logsize);

	return offset & (fs->blocksize - 1);
	}

	int ext2_get_inode_state(struct ext2_fs *fs, ino_t inode)
	{
	struct ext2_buffer_head *bh;
	int group;
	int offset;
	int ret;

	inode--;
	group = inode / EXT2_SUPER_INODES_PER_GROUP(fs->sb);
	offset = inode % EXT2_SUPER_INODES_PER_GROUP(fs->sb);

	bh = ext2_bread(fs, EXT2_GROUP_INODE_BITMAP(fs->gd[group]));
	ret = bh->data[offset>>3] & _bitmap[offset&7];
	ext2_brelse(bh, 0);

	return ret;
	}

	int ext2_read_inode(struct ext2_fs fs, ino_t inode, struct ext2_inode data)
	{
	struct ext2_buffer_head *bh;
	blk_t blk;
	off_t off;

	off = ext2_get_inode_offset(fs, inode, &blk);

	bh = ext2_bread(fs, blk);
	if (!bh)
	return 0;

	memcpy(data, bh->data + off, sizeof(struct ext2_inode));
	ext2_brelse(bh, 0);
	return 1;
	}

	int ext2_set_inode_state(struct ext2_fs *fs, ino_t inode, int state, int updatemetadata)
	{
	struct ext2_buffer_head *bh;
	int group;
	int offset;

	inode--;
	group = inode / EXT2_SUPER_INODES_PER_GROUP(fs->sb);
	offset = inode % EXT2_SUPER_INODES_PER_GROUP(fs->sb);

	bh = ext2_bread(fs, EXT2_GROUP_INODE_BITMAP(fs->gd[group]));
	if (!bh)
	return 0;
	bh->dirty = 1;
	if (state)
	bh->data[offset>>3] \|= _bitmap[offset&7];
	else
	bh->data[offset>>3] &= ~_bitmap[offset&7];
	ext2_brelse(bh, 0);

	if (updatemetadata)
	{
	int diff;

	diff = state ? -1 : 1;

	fs->gd[group].bg_free_inodes_count = PED_CPU_TO_LE16
	(EXT2_GROUP_FREE_INODES_COUNT(fs->gd[group]) + diff);
	fs->sb.s_free_inodes_count = PED_CPU_TO_LE32
	(EXT2_SUPER_FREE_INODES_COUNT(fs->sb) + diff);
	fs->metadirty = EXT2_META_SB \| EXT2_META_GD;
	}
	return 1;
	}

	static void
	_inode_update_size(struct ext2_fs fs, struct ext2_inode inode, int delta)
	{
	int i512perblock = 1 << (fs->logsize - 9);
	uint64_t size;

	/* i_blocks is in 512 byte blocks */
	inode->i_blocks = PED_CPU_TO_LE32(EXT2_INODE_BLOCKS(*inode)
	+ delta * i512perblock);
	size = EXT2_INODE_SIZE(inode) + delta fs->blocksize;
	inode->i_size = PED_CPU_TO_LE32(size % (1LL << 32));
	inode->i_size_high = PED_CPU_TO_LE32(size / (1LL << 32));
	inode->i_mtime = PED_CPU_TO_LE32(time(NULL));
	}

	int ext2_do_inode(struct ext2_fs fs, struct ext2_inode inode, blk_t block,
	int action)
	{
	struct ext2_buffer_head *bh;
	uint32_t *udata;
	blk_t count = 0;
	int i;
	int u32perblock = fs->blocksize >> 2;
	int i512perblock = 1 << (fs->logsize - 9);

	if (block == 0 \|\| EXT2_INODE_MODE(*inode) == 0)
	return -1;

	if (fs->opt_debug)
	switch (action)
	{
	case EXT2_ACTION_ADD:
	fprintf(stderr,"adding 0x%04x to inode\n",
	block);
	break;
	case EXT2_ACTION_DELETE:
	fprintf(stderr,"deleting 0x%04x from inode\n",
	block);
	break;
	case EXT2_ACTION_FIND:
	fprintf(stderr,"finding 0x%04x in inode\n",
	block);
	break;
	}

	/* Direct blocks for first 12 blocks */
	for (i = 0; i < EXT2_NDIR_BLOCKS; i++)
	{
	if (action == EXT2_ACTION_ADD && !EXT2_INODE_BLOCK(*inode, i))
	{
	inode->i_block[i] = PED_CPU_TO_LE32(block);
	_inode_update_size (fs, inode, 1);
	ext2_set_block_state(fs, block, 1, 1);
	return i;
	}
	if (EXT2_INODE_BLOCK(*inode, i) == block)
	{
	if (action == EXT2_ACTION_DELETE)
	{
	inode->i_block[i] = 0;
	_inode_update_size (fs, inode, -1);
	ext2_set_block_state(fs, block, 0, 1);
	}
	return i;
	}
	if (EXT2_INODE_BLOCK(*inode, i))
	count += i512perblock;
	}

	count += EXT2_INODE_BLOCK(*inode, EXT2_IND_BLOCK) ? i512perblock : 0;
	count += EXT2_INODE_BLOCK(*inode, EXT2_DIND_BLOCK) ? i512perblock : 0;
	count += EXT2_INODE_BLOCK(*inode, EXT2_TIND_BLOCK) ? i512perblock : 0;

	if (!EXT2_INODE_BLOCK(*inode, EXT2_IND_BLOCK) \|\|
	(count >= EXT2_INODE_BLOCKS(*inode) && action != EXT2_ACTION_ADD))
	return -1;

	bh = ext2_bread(fs, EXT2_INODE_BLOCK(*inode, EXT2_IND_BLOCK));
	udata = (uint32_t *)bh->data;

	/* Indirect blocks for next 256/512/1024 blocks (for 1k/2k/4k blocks) */
	for (i = 0; i < u32perblock; i++) {
	if (action == EXT2_ACTION_ADD && !udata[i]) {
	bh->dirty = 1;
	udata[i] = PED_CPU_TO_LE32(block);
	_inode_update_size (fs, inode, 1);
	ext2_set_block_state(fs, block, 1, 1);
	ext2_brelse(bh, 0);
	return EXT2_NDIR_BLOCKS + i;
	}
	if (PED_LE32_TO_CPU(udata[i]) == block) {
	if (action == EXT2_ACTION_DELETE) {
	bh->dirty = 1;
	udata[i] = 0;
	_inode_update_size (fs, inode, -1);
	ext2_set_block_state(fs, block, 0, 1);
	}
	ext2_brelse(bh, 0);
	return EXT2_NDIR_BLOCKS + i;
	}
	if (udata[i])
	{
	count += i512perblock;
	if (count >= EXT2_INODE_BLOCKS(*inode) &&
	action != EXT2_ACTION_ADD)
	return -1;
	}
	}

	ext2_brelse(bh, 0);

	if (!EXT2_INODE_BLOCK(*inode, EXT2_DIND_BLOCK) \|\|
	(count >= EXT2_INODE_BLOCKS(*inode) && action != EXT2_ACTION_ADD))
	return -1;
	bh = ext2_bread(fs, EXT2_INODE_BLOCK(*inode, EXT2_DIND_BLOCK));
	udata = (uint32_t *)bh->data;

	/* Double indirect blocks for next 2^16/2^18/2^20 1k/2k/4k blocks */
	for (i = 0; i < u32perblock; i++) {
	struct ext2_buffer_head *bh2;
	uint32_t *udata2;
	int j;

	if (!udata[i]) {
	ext2_brelse(bh, 0);
	return -1;
	}
	bh2 = ext2_bread(fs, PED_LE32_TO_CPU(udata[i]));
	udata2 = (uint32_t *)bh2->data;
	count += i512perblock;

	for (j = 0; j < u32perblock; j++) {
	if (action == EXT2_ACTION_ADD && !udata2[j]) {
	bh2->dirty = 1;
	udata2[j] = PED_CPU_TO_LE32(block);
	_inode_update_size (fs, inode, 1);
	ext2_set_block_state(fs, block, 1, 1);
	ext2_brelse(bh, 0);
	ext2_brelse(bh2, 0);
	return EXT2_NDIR_BLOCKS + i * u32perblock + j;
	}
	if (PED_LE32_TO_CPU(udata2[j]) == block) {
	if (action == EXT2_ACTION_DELETE) {
	bh2->dirty = 1;
	udata2[j] = 0;
	_inode_update_size (fs, inode, -1);
	ext2_set_block_state(fs, block, 0, 1);
	}
	ext2_brelse(bh, 0);
	ext2_brelse(bh2, 0);
	return EXT2_NDIR_BLOCKS + i * u32perblock + j;
	}
	if (udata2[j])
	{
	count += i512perblock;
	if (count >= EXT2_INODE_BLOCKS(*inode) &&
	action != EXT2_ACTION_ADD)
	return -1;
	}
	}
	ext2_brelse(bh2, 0);
	}
	ext2_brelse(bh, 0);

	/* FIXME: we should check for triple-indirect blocks here, but it
	* would be nice to have a better routine to traverse blocks, and
	* file systems that need triple-indirect blocks for the resize
	* inode are too big to worry about yet.
	*/

	return -1;
	}

	int ext2_write_inode(struct ext2_fs fs, ino_t inode, const struct ext2_inode data)
	{
	struct ext2_buffer_head *bh;
	blk_t blk;
	off_t off;

	off = ext2_get_inode_offset(fs, inode, &blk);

	bh = ext2_bread(fs, blk);
	if (!bh)
	return 0;
	bh->dirty = 1;
	memcpy(bh->data + off, data, sizeof(struct ext2_inode));
	ext2_brelse(bh, 0);

	return 1;
	}

	int ext2_zero_inode(struct ext2_fs *fs, ino_t inode)
	{
	struct ext2_inode buf;

	memset(&buf, 0, sizeof(struct ext2_inode));
	return ext2_write_inode(fs, inode, &buf);
	}





	/* check whether y is root of x
	* (formula grabbed from linux ext2 kernel source) */
	static int is_root(int x, int y)
	{
	if (!x)
	return 1;

	while (1)
	{
	if (x == 1)
	return 1;

	if (x % y)
	return 0;

	x /= y;
	}
	}

	/* check whether group contains a superblock copy on file systems
	* where not all groups have one (sparse superblock feature) */
	int ext2_is_group_sparse(struct ext2_fs *fs, int group)
	{
	if (!fs->sparse)
	return 1;

	if (is_root(group, 3) \|\| is_root(group, 5) \|\| is_root(group, 7))
	return 1;

	return 0;
	}

	void ext2_close(struct ext2_fs *fs)
	{
	ext2_commit_metadata(fs, EXT2_META_PRIMARY \| EXT2_META_BACKUP);
	ext2_sync(fs);

	ext2_bcache_deinit(fs);

	fs->devhandle->ops->close(fs->devhandle->cookie);

	ped_free(fs->gd);
	ped_free(fs);
	}

	int ext2_commit_metadata(struct ext2_fs *fs, int copies)
	{
	int i;
	int num;
	int wmeta = fs->metadirty & copies;
	unsigned char* sb = ped_malloc(fs->blocksize);
	struct ext2_super_block *sb_for_io;
	int sb_block;

	/* See if there is even anything to write... */
	if (wmeta == EXT2_META_CLEAN)
	return 1;

	fs->sb.s_r_blocks_count = PED_CPU_TO_LE32 (
	fs->r_frac * (loff_t)EXT2_SUPER_BLOCKS_COUNT(fs->sb)
	/ 100);

	if (!ext2_read_blocks (fs, sb, 0, 1))
	return 0;

	if (EXT2_SUPER_FIRST_DATA_BLOCK(fs->sb)) {
	memcpy(sb, &fs->sb, 1024);
	sb_for_io = (struct ext2_super_block *) sb;
	} else {
	memcpy(sb+1024, &fs->sb, 1024);
	sb_for_io = (struct ext2_super_block *) (sb + 1024);
	}

	num = copies & EXT2_META_BACKUP ? fs->numgroups : 1;

	for (i = 0, sb_block = EXT2_SUPER_FIRST_DATA_BLOCK(fs->sb); i < num;
	i++, sb_block += EXT2_SUPER_BLOCKS_PER_GROUP(fs->sb))
	{

	if (!ext2_is_group_sparse(fs, i))
	continue;

	if (fs->dynamic_version)
	sb_for_io->s_block_group_nr = PED_CPU_TO_LE16 (i);

	if ((i == 0 && wmeta & EXT2_META_PRIMARY_SB) \|\|
	(i != 0 && wmeta & EXT2_META_SB))
	{
	if (!ext2_bcache_flush_range(fs, sb_block, 1))
	return 0;
	if (!ext2_write_blocks(fs, sb, sb_block, 1))
	return 0;
	}
	if ((i == 0 && wmeta & EXT2_META_PRIMARY_GD) \|\|
	(i != 0 && wmeta & EXT2_META_GD))
	{
	if (!ext2_bcache_flush_range(fs, sb_block + 1,
	fs->gdblocks))
	return 0;
	if (!ext2_write_blocks(fs, fs->gd, sb_block + 1,
	fs->gdblocks))
	return 0;
	}
	}

	sb_for_io->s_block_group_nr = 0;

	/* Clear the flags of the components we just finished writing. */
	fs->metadirty &= ~copies;

	return 1;
	}

	int ext2_sync(struct ext2_fs *fs)
	{
	if (!ext2_commit_metadata(fs, EXT2_META_PRIMARY)) return 0;
	if (!ext2_bcache_sync(fs)) return 0;
	if (!fs->devhandle->ops->sync(fs->devhandle->cookie)) return 0;
	return 1;
	}

	struct ext2_fs ext2_open(struct ext2_dev_handle handle, int state)
	{
	struct ext2_fs *fs;

	if ((fs = (struct ext2_fs *) ped_malloc(sizeof(struct ext2_fs)))
	== NULL)
	goto error;

	handle->ops->set_blocksize(handle->cookie, 10);

	if (!handle->ops->read(handle->cookie, &fs->sb, 1, 1)
	\|\| EXT2_SUPER_MAGIC(fs->sb) != EXT2_SUPER_MAGIC_CONST)
	{
	ped_exception_throw (PED_EXCEPTION_ERROR, PED_EXCEPTION_CANCEL,
	_("Invalid superblock. Are you sure this is an ext2 "
	"file system?"));
	goto error_free_fs;
	}


	fs->opt_debug = 1;
	fs->opt_safe = 1;
	fs->opt_verbose = 0;

	if (EXT2_SUPER_STATE(fs->sb) & EXT2_ERROR_FS & ~(state & EXT2_ERROR_FS))
	{
	if (ped_exception_throw (
	PED_EXCEPTION_WARNING, PED_EXCEPTION_IGNORE_CANCEL,
	_("File system has errors! You should run e2fsck."))
	== PED_EXCEPTION_CANCEL)
	goto error_free_fs;
	}

	if (!((EXT2_SUPER_STATE(fs->sb) \| state) & EXT2_VALID_FS)
	\|\| (EXT2_SUPER_FEATURE_INCOMPAT(fs->sb)
	& EXT3_FEATURE_INCOMPAT_RECOVER))
	{
	if (ped_exception_throw (
	PED_EXCEPTION_ERROR, PED_EXCEPTION_IGNORE_CANCEL,
	_("File system was not cleanly unmounted! "
	"You should run e2fsck. Modifying an unclean "
	"file system could cause severe corruption."))
	!= PED_EXCEPTION_IGNORE)
	goto error_free_fs;
	}

	fs->dynamic_version = EXT2_SUPER_REV_LEVEL (fs->sb) > 0;

	if ((EXT2_SUPER_FEATURE_COMPAT(fs->sb)
	& ~(EXT3_FEATURE_COMPAT_HAS_JOURNAL \|
	EXT2_FEATURE_COMPAT_HAS_DIR_INDEX)) \|\|
	(EXT2_SUPER_FEATURE_INCOMPAT(fs->sb)
	& ~(EXT2_FEATURE_INCOMPAT_FILETYPE \|
	EXT3_FEATURE_INCOMPAT_RECOVER)) \|\|
	(EXT2_SUPER_FEATURE_RO_COMPAT(fs->sb)
	& ~(EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER \|
	EXT2_FEATURE_RO_COMPAT_LARGE_FILE)))
	{
	ped_exception_throw (PED_EXCEPTION_ERROR, PED_EXCEPTION_CANCEL,
	_("File system has an incompatible feature enabled."));
	goto error_free_fs;
	}

	fs->devhandle = handle;
	fs->logsize = EXT2_SUPER_LOG_BLOCK_SIZE(fs->sb) + 10;
	handle->ops->set_blocksize(handle->cookie, fs->logsize);

	if (!ext2_bcache_init(fs))
	{
	ped_exception_throw (PED_EXCEPTION_ERROR, PED_EXCEPTION_CANCEL,
	_("Error allocating buffer cache."));
	goto error_free_fs;
	}

	fs->blocksize = 1 << fs->logsize;

	fs->numgroups = ped_div_round_up (EXT2_SUPER_BLOCKS_COUNT(fs->sb)
	- EXT2_SUPER_FIRST_DATA_BLOCK(fs->sb),
	EXT2_SUPER_BLOCKS_PER_GROUP(fs->sb));
	fs->gdblocks = ped_div_round_up (fs->numgroups
	* sizeof(struct ext2_group_desc),
	fs->blocksize);
	fs->inodeblocks = ped_div_round_up (EXT2_SUPER_INODES_PER_GROUP(fs->sb)
	* sizeof(struct ext2_inode),
	fs->blocksize);
	fs->r_frac = ped_div_round_up (100 * (loff_t)EXT2_SUPER_R_BLOCKS_COUNT(fs->sb),
	EXT2_SUPER_BLOCKS_COUNT(fs->sb));
	fs->adminblocks = 3 + fs->gdblocks + fs->inodeblocks;

	fs->sparse = 0;
	if (EXT2_SUPER_FEATURE_RO_COMPAT(fs->sb)
	& EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER)
	fs->sparse = 1;

	fs->has_journal = 0 < (EXT2_SUPER_FEATURE_COMPAT(fs->sb)
	& EXT3_FEATURE_COMPAT_HAS_JOURNAL);
	fs->has_internal_journal
	= fs->has_journal
	&& uuid_is_null(EXT2_SUPER_JOURNAL_UUID(fs->sb))
	&& EXT2_SUPER_JOURNAL_INUM(fs->sb);

	fs->gd = ped_malloc (fs->numgroups * sizeof (struct ext2_group_desc)
	+ fs->blocksize);
	if (!fs->gd)
	goto error_deinit_bcache;

	ext2_read_blocks(fs, fs->gd, EXT2_SUPER_FIRST_DATA_BLOCK(fs->sb) + 1,
	fs->gdblocks);

	fs->metadirty = 0;
	return fs;

	ped_free(fs->gd);
	error_deinit_bcache:
	ext2_bcache_deinit(fs);
	error_free_fs:
	ped_free(fs);
	error:
	return NULL;
	}

	#endif /* !DISCOVER_ONLY */