[thirdparty/e2fsprogs.git] / resize / resize2fs.c

/*
 * resize2fs.c --- ext2 main routine
 *
 * Copyright (C) 1997 Theodore Ts'o
 * 
 * %Begin-Header%
 * All rights reserved.
 * %End-Header%
 */

#include "resize2fs.h"

/*
 * This routine adjusts the superblock and other data structures...
 */
static errcode_t adjust_superblock(ext2_resize_t rfs, blk_t new_size)
{
	ext2_filsys fs;
	int		overhead = 0;
	int		rem;
	errcode_t	retval;
	ino_t		real_end;
	blk_t		blk, group_block;
	unsigned long	i, j;
	struct ext2_group_desc *new;
	char		*buf;
	int		old_numblocks, numblocks, adjblocks;
	
	fs = rfs->new_fs;
	fs->super->s_blocks_count = new_size;
	ext2fs_mark_super_dirty(fs);
	ext2fs_mark_bb_dirty(fs);
	ext2fs_mark_ib_dirty(fs);

retry:
	fs->group_desc_count = (fs->super->s_blocks_count -
				fs->super->s_first_data_block +
				EXT2_BLOCKS_PER_GROUP(fs->super) - 1)
		/ EXT2_BLOCKS_PER_GROUP(fs->super);
	if (fs->group_desc_count == 0)
		return EXT2_ET_TOOSMALL;
	fs->desc_blocks = (fs->group_desc_count +
			   EXT2_DESC_PER_BLOCK(fs->super) - 1)
		/ EXT2_DESC_PER_BLOCK(fs->super);

	/*
	 * Overhead is the number of bookkeeping blocks per group.  It
	 * includes the superblock backup, the group descriptor
	 * backups, the inode bitmap, the block bitmap, and the inode
	 * table.
	 *
	 * XXX Not all block groups need the descriptor blocks, but
	 * being clever is tricky...
	 */
	overhead = 3 + fs->desc_blocks + fs->inode_blocks_per_group;
	
	/*
	 * See if the last group is big enough to support the
	 * necessary data structures.  If not, we need to get rid of
	 * it.
	 */
	rem = (fs->super->s_blocks_count - fs->super->s_first_data_block) %
		fs->super->s_blocks_per_group;
	if ((fs->group_desc_count == 1) && rem && (rem < overhead))
		return EXT2_ET_TOOSMALL;
	if (rem && (rem < overhead+50)) {
		fs->super->s_blocks_count -= rem;
		goto retry;
	}
	/*
	 * Adjust the number of inodes
	 */
	fs->super->s_inodes_count = fs->super->s_inodes_per_group *
		fs->group_desc_count;

	/*
	 * Adjust the number of free blocks
	 */
	blk = rfs->old_fs->super->s_blocks_count;
	if (blk > fs->super->s_blocks_count)
		fs->super->s_free_blocks_count -=
			(blk - fs->super->s_blocks_count);
	else
		fs->super->s_free_blocks_count +=
			(fs->super->s_blocks_count - blk);

	/*
	 * Adjust the bitmaps for size
	 */
	retval = ext2fs_resize_inode_bitmap(fs->super->s_inodes_count,
					    fs->super->s_inodes_count,
					    fs->inode_map);
	if (retval)
		return retval;
	
	real_end = ((EXT2_BLOCKS_PER_GROUP(fs->super)
		     * fs->group_desc_count)) - 1 +
			     fs->super->s_first_data_block;
	retval = ext2fs_resize_block_bitmap(fs->super->s_blocks_count-1,
					    real_end, fs->block_map);

	if (retval)
		return retval;

	/*
	 * Reallocate the group descriptors as necessary.
	 */
	if (rfs->old_fs->desc_blocks != fs->desc_blocks) {
		new = realloc(fs->group_desc,
			      fs->desc_blocks * fs->blocksize);
		if (!new)
			return ENOMEM;
		fs->group_desc = new;
	}

	/*
	 * Fix the count of the last (old) block group
	 */
	if (rfs->old_fs->group_desc_count > fs->group_desc_count)
		return 0;
	old_numblocks = (rfs->old_fs->super->s_blocks_count -
			 rfs->old_fs->super->s_first_data_block) %
				 rfs->old_fs->super->s_blocks_per_group;
	if (!old_numblocks)
		old_numblocks = rfs->old_fs->super->s_blocks_per_group;
	if (rfs->old_fs->group_desc_count == fs->group_desc_count) {
		numblocks = (rfs->new_fs->super->s_blocks_count -
			     rfs->new_fs->super->s_first_data_block) %
				     rfs->new_fs->super->s_blocks_per_group;
		if (!numblocks)
			numblocks = rfs->new_fs->super->s_blocks_per_group;
	} else
		numblocks = rfs->new_fs->super->s_blocks_per_group;
	i = rfs->old_fs->group_desc_count - 1;
	fs->group_desc[i].bg_free_blocks_count += (numblocks-old_numblocks);
		
	/*
	 * Initialize the new block group descriptors
	 */
	if (rfs->old_fs->group_desc_count >= fs->group_desc_count)
		return 0;
	buf = malloc(fs->blocksize);
	if (!buf)
		return ENOMEM;
	memset(buf, 0, fs->blocksize);
	group_block = fs->super->s_first_data_block +
		rfs->old_fs->group_desc_count * fs->super->s_blocks_per_group;
	for (i = rfs->old_fs->group_desc_count;
	     i < fs->group_desc_count; i++) {
		memset(&fs->group_desc[i], 0,
		       sizeof(struct ext2_group_desc));
		adjblocks = 0;

		if (i == 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;

		if (ext2fs_bg_has_super(fs, i)) {
			for (j=0; j < fs->desc_blocks+1; j++)
				ext2fs_mark_block_bitmap(fs->block_map,
							 group_block + j);
			adjblocks = 1 + fs->desc_blocks;
		}
		adjblocks += 2 + fs->inode_blocks_per_group;
		
		numblocks -= adjblocks;
		fs->super->s_free_blocks_count -= adjblocks;
		fs->super->s_free_inodes_count +=
			fs->super->s_inodes_per_group;
		fs->group_desc[i].bg_free_blocks_count = numblocks;
		fs->group_desc[i].bg_free_inodes_count =
			fs->super->s_inodes_per_group;
		fs->group_desc[i].bg_used_dirs_count = 0;

		retval = ext2fs_allocate_group_table(fs, i, 0);
		if (retval)
			return retval;

		for (blk=fs->group_desc[i].bg_inode_table, j=0;
		     j < fs->inode_blocks_per_group;
		     blk++, j++) {
			retval = io_channel_write_blk(fs->io, blk, 1, buf);
			if (retval)
				return retval;
		}
		group_block += fs->super->s_blocks_per_group;
	}
	return 0;
}

/*
 * This routine marks and unmarks reserved blocks in the new block
 * bitmap.  It also determines which blocks need to be moved and
 * places this information into the move_blocks bitmap.
 */
static errcode_t determine_relocations(ext2_resize_t rfs)
{
	int	i, j, max, adj;
	blk_t	blk, group_blk;
	unsigned long old_blocks, new_blocks;
	errcode_t	retval;
	ext2_filsys 	fs = rfs->new_fs;

	retval = ext2fs_allocate_block_bitmap(rfs->old_fs,
					      "blocks to be moved",
					      &rfs->reserve_blocks);
	if (retval)
		return retval;

	/*
	 * If we're shrinking the filesystem, we need to move all of
	 * the blocks that don't fit any more
	 */
	for (blk = fs->super->s_blocks_count;
	     blk < rfs->old_fs->super->s_blocks_count; blk++) {
		if (ext2fs_test_block_bitmap(rfs->old_fs->block_map, blk))
			rfs->needed_blocks++;
		ext2fs_mark_block_bitmap(rfs->reserve_blocks, blk);
	}
	
	old_blocks = rfs->old_fs->desc_blocks;
	new_blocks = fs->desc_blocks;

	if (old_blocks == new_blocks)
		return 0;

	max = fs->group_desc_count;
	if (max > rfs->old_fs->group_desc_count)
		max = rfs->old_fs->group_desc_count;
	group_blk = rfs->old_fs->super->s_first_data_block;
	/*
	 * If we're reducing the number of descriptor blocks, this
	 * makes life easy.  :-)   We just have to mark some extra
	 * blocks as free.
	 */
	if (old_blocks > new_blocks) {
		for (i = 0; i < max; i++) {
			if (!ext2fs_bg_has_super(fs, i)) {
				group_blk += fs->super->s_blocks_per_group;
				continue;
			}
			for (blk = group_blk+1+old_blocks;
			     blk < group_blk+1+new_blocks; blk++) {
				ext2fs_unmark_block_bitmap(fs->block_map,
							   blk);
				rfs->needed_blocks--;
			}
			group_blk += fs->super->s_blocks_per_group;
		}
		return 0;
	}
	/*
	 * If we're increasing the number of descriptor blocks, life
	 * gets interesting....  
	 */
	for (i = 0; i < max; i++) {
		if (!ext2fs_bg_has_super(fs, i))
			goto next_group;

		for (blk = group_blk;
		     blk < group_blk + 1 + new_blocks; blk++) {
			ext2fs_mark_block_bitmap(rfs->reserve_blocks, blk);
			ext2fs_mark_block_bitmap(fs->block_map, blk);

			/*
			 * Check to see if we overlap with the inode
			 * or block bitmap
			 */
			if (blk == fs->group_desc[i].bg_block_bitmap) {
				fs->group_desc[i].bg_block_bitmap = 0;
				rfs->needed_blocks++;
			}
			if (blk == fs->group_desc[i].bg_inode_bitmap) {
				fs->group_desc[i].bg_inode_bitmap = 0;
				rfs->needed_blocks++;
			}
			/*
			 * Check to see if we overlap with the inode
			 * table
			 */
			if (blk < fs->group_desc[i].bg_inode_table)
				continue;
			if (blk >= (fs->group_desc[i].bg_inode_table +
				    fs->inode_blocks_per_group))
				continue;
			fs->group_desc[i].bg_inode_table = 0;
			blk = fs->group_desc[i].bg_inode_table +
				fs->inode_blocks_per_group - 1;
		}
		if (fs->group_desc[i].bg_inode_table &&
		    fs->group_desc[i].bg_inode_bitmap &&
		    fs->group_desc[i].bg_block_bitmap)
			goto next_group;

		/*
		 * Allocate the missing bitmap and inode table
		 * structures, passing in rfs->reserve_blocks to
		 * prevent a conflict.  
		 */
		if (fs->group_desc[i].bg_block_bitmap)
			ext2fs_mark_block_bitmap(rfs->reserve_blocks,
				 fs->group_desc[i].bg_block_bitmap);
		if (fs->group_desc[i].bg_inode_bitmap)
			ext2fs_mark_block_bitmap(rfs->reserve_blocks,
				 fs->group_desc[i].bg_inode_bitmap);
		if (fs->group_desc[i].bg_inode_table)
			for (blk = fs->group_desc[i].bg_inode_table, j=0;
			     j < fs->inode_blocks_per_group ; j++, blk++)
				ext2fs_mark_block_bitmap(rfs->reserve_blocks,
							 blk);

		retval = ext2fs_allocate_group_table(fs, i,
						     rfs->reserve_blocks);
		if (retval)
			return retval;

		/*
		 * Now make sure these blocks are reserved in the new
		 * block bitmap
		 */
		ext2fs_mark_block_bitmap(fs->block_map,
					 fs->group_desc[i].bg_block_bitmap);
		ext2fs_mark_block_bitmap(fs->block_map,
					 fs->group_desc[i].bg_inode_bitmap);

		/*
		 * The inode table, if we need to relocate it, is
		 * handled specially.  We have to reserve the blocks
		 * for both the old and the new inode table, since we
		 * can't have the inode table be destroyed during the
		 * block relocation phase.
		 */
		adj = fs->group_desc[i].bg_inode_table -
			rfs->old_fs->group_desc[i].bg_inode_table;
		if (!adj)
			goto next_group; /* inode table not moved */

		/*
		 * Figure out how many blocks we need to have free.
		 * This takes into account that we need to reserve
		 * both inode tables, which may be overallping.
		 */
		if (adj < 0)
			adj = -adj;
		if (adj > fs->inode_blocks_per_group)
			adj = fs->inode_blocks_per_group;
		rfs->needed_blocks += fs->inode_blocks_per_group + adj;

		/*
		 * Mark the new inode table as in use in the new block
		 * allocation bitmap.
		 */
		for (blk = fs->group_desc[i].bg_inode_table, j=0;
		     j < fs->inode_blocks_per_group ; j++, blk++)
			ext2fs_mark_block_bitmap(fs->block_map, blk);
		/*
		 * Make sure the old inode table is reserved in the
		 * block reservation bitmap.
		 */
		for (blk = rfs->old_fs->group_desc[i].bg_inode_table, j=0;
		     j < fs->inode_blocks_per_group ; j++, blk++)
			ext2fs_mark_block_bitmap(rfs->reserve_blocks, blk);
		
	next_group:
		group_blk += rfs->new_fs->super->s_blocks_per_group;
	}
	return 0;
}


/*
 * A very scary routine --- this one moves the inode table around!!!
 *
 * After this you have to use the rfs->new_fs file handle to read and
 * write inodes.
 */
errcode_t move_itables(ext2_resize_t rfs)
{
	int	i, max;
	ext2_filsys	fs = rfs->new_fs;
	char		*buf;
	blk_t		old, new;
	errcode_t	retval, err;

	printf("Hide the women and children --- "
	       "commencing inode table moves!!\n");
	
	max = fs->group_desc_count;
	if (max > rfs->old_fs->group_desc_count)
		max = rfs->old_fs->group_desc_count;

	buf = malloc(fs->blocksize * fs->inode_blocks_per_group);
	if (!buf)
		return ENOMEM;
	
	for (i=0; i < max; i++) {
		old = rfs->old_fs->group_desc[i].bg_inode_table;
		new = fs->group_desc[i].bg_inode_table;
		
		printf("Group %d block %ld->%ld\n", i, old, new);
		
		if (old == new)
			continue;

		retval = io_channel_read_blk(fs->io, old,
					     fs->inode_blocks_per_group, buf);
		if (retval) 
			goto backout;
		retval = io_channel_write_blk(fs->io, new,
					      fs->inode_blocks_per_group, buf);
		if (retval) {
			io_channel_write_blk(fs->io, old,
					      fs->inode_blocks_per_group, buf);
			goto backout;
		}
	}
	ext2fs_flush(rfs->new_fs);
	printf("Inode table move finished.\n");
	return 0;
	
backout:
	printf("Error: %s; now backing out!\n", error_message(retval));
	while (--i >= 0) {
		printf("Group %d block %ld->%ld\n", i, new, old);
		old = rfs->old_fs->group_desc[i].bg_inode_table;
		new = fs->group_desc[i].bg_inode_table;
		
		err = io_channel_read_blk(fs->io, new,
					  fs->inode_blocks_per_group, buf);
		if (err)
			continue;
		err = io_channel_write_blk(fs->io, old,
					   fs->inode_blocks_per_group, buf);
	}
	return retval;
}

/*
 * Finally, recalculate the summary information
 */
static errcode_t ext2fs_calculate_summary_stats(ext2_filsys fs)
{
	blk_t	blk;
	ino_t	ino;
	int	group = 0;
	int	count = 0;
	int	total_free = 0;
	int	group_free = 0;

	/*
	 * First calculate the block statistics
	 */
	for (blk = fs->super->s_first_data_block;
	     blk < fs->super->s_blocks_count; blk++) {
		if (!ext2fs_fast_test_block_bitmap(fs->block_map, blk)) {
			group_free++;
			total_free++;
		}
		count++;
		if ((count == fs->super->s_blocks_per_group) ||
		    (blk == fs->super->s_blocks_count-1)) {
			fs->group_desc[group++].bg_free_blocks_count =
				group_free;
			count = 0;
			group_free = 0;
		}
	}
	fs->super->s_free_blocks_count = total_free;
	
	/*
	 * Next, calculate the inode statistics
	 */
	group_free = 0;
	total_free = 0;
	count = 0;
	group = 0;
	for (ino = 1; ino <= fs->super->s_inodes_count; ino++) {
		if (!ext2fs_fast_test_inode_bitmap(fs->inode_map, ino)) {
			group_free++;
			total_free++;
		}
		count++;
		if ((count == fs->super->s_inodes_per_group) ||
		    (ino == fs->super->s_inodes_count)) {
			fs->group_desc[group++].bg_free_inodes_count =
				group_free;
			count = 0;
			group_free = 0;
		}
	}
	fs->super->s_free_inodes_count = total_free;
	ext2fs_mark_super_dirty(fs);
	return 0;
}


/*
 * This is the top-level routine which does the dirty deed....
 */
errcode_t resize_fs(ext2_filsys fs, blk_t new_size)
{
	ext2_resize_t	rfs;
	errcode_t	retval;

	retval = ext2fs_read_bitmaps(fs);
	if (retval)
		return retval;
	
	/*
	 * Create the data structure
	 */
	rfs = malloc(sizeof(struct ext2_resize_struct));
	if (!rfs)
		return ENOMEM;
	memset(rfs, 0, sizeof(struct ext2_resize_struct));

	rfs->old_fs = fs;
	retval = ext2fs_dup_handle(fs, &rfs->new_fs);
	if (retval)
		goto errout;

	retval = adjust_superblock(rfs, new_size);
	if (retval)
		goto errout;

	retval = determine_relocations(rfs);
	if (retval)
		goto errout;

	printf("Number of free blocks: %d, Needed: %d\n",
	       fs->super->s_free_blocks_count, rfs->needed_blocks);
	
	if (rfs->needed_blocks > fs->super->s_free_blocks_count) {
		retval = ENOSPC;
		goto errout;
	}
	
	printf("\nOld superblock:\n");
	list_super(rfs->old_fs->super);
	printf("\n\nNew superblock:\n");
	list_super(rfs->new_fs->super);
	printf("\n");

	retval = ext2fs_move_blocks(rfs->old_fs, rfs->reserve_blocks,
				    rfs->new_fs->block_map,
				    EXT2_BMOVE_GET_DBLIST);
	if (retval)
		return retval;

	retval = ext2fs_inode_move(rfs);
	if (retval)
		return retval;

	retval = move_itables(rfs);
	if (retval)
		return retval;

	retval = ext2fs_calculate_summary_stats(rfs->new_fs);
	if (retval)
		return retval;
	
	retval = ext2fs_close(rfs->new_fs);
	if (retval)
		return retval;
	
	ext2fs_free(rfs->old_fs);
	
	return 0;

errout:
	if (rfs->new_fs)
		ext2fs_free(rfs->new_fs);
	free(rfs);
	return retval;
}
Commit	Line	Data
24b2c7a7 TT	1	/*
	2	* resize2fs.c --- ext2 main routine
	3	*
	4	* Copyright (C) 1997 Theodore Ts'o
	5	*
	6	* %Begin-Header%
	7	* All rights reserved.
	8	* %End-Header%
	9	*/
	10
	11	#include "resize2fs.h"
	12
	13	/*
	14	* This routine adjusts the superblock and other data structures...
	15	*/
	16	static errcode_t adjust_superblock(ext2_resize_t rfs, blk_t new_size)
	17	{
	18	ext2_filsys fs;
	19	int overhead = 0;
	20	int rem;
	21	errcode_t retval;
	22	ino_t real_end;
	23	blk_t blk, group_block;
1e1da29f	24	unsigned long i, j;
24b2c7a7	25	struct ext2_group_desc *new;
1e1da29f TT	26	char *buf;
1e1da29f TT	27	int old_numblocks, numblocks, adjblocks;
24b2c7a7 TT	28
	29	fs = rfs->new_fs;
	30	fs->super->s_blocks_count = new_size;
1e1da29f TT	31	ext2fs_mark_super_dirty(fs);
	32	ext2fs_mark_bb_dirty(fs);
	33	ext2fs_mark_ib_dirty(fs);
24b2c7a7 TT	34
	35	retry:
	36	fs->group_desc_count = (fs->super->s_blocks_count -
	37	fs->super->s_first_data_block +
	38	EXT2_BLOCKS_PER_GROUP(fs->super) - 1)
	39	/ EXT2_BLOCKS_PER_GROUP(fs->super);
	40	if (fs->group_desc_count == 0)
	41	return EXT2_ET_TOOSMALL;
	42	fs->desc_blocks = (fs->group_desc_count +
	43	EXT2_DESC_PER_BLOCK(fs->super) - 1)
	44	/ EXT2_DESC_PER_BLOCK(fs->super);
	45
	46	/*
	47	* Overhead is the number of bookkeeping blocks per group. It
	48	* includes the superblock backup, the group descriptor
	49	* backups, the inode bitmap, the block bitmap, and the inode
	50	* table.
	51	*
	52	* XXX Not all block groups need the descriptor blocks, but
	53	* being clever is tricky...
	54	*/
	55	overhead = 3 + fs->desc_blocks + fs->inode_blocks_per_group;
	56
	57	/*
	58	* See if the last group is big enough to support the
	59	* necessary data structures. If not, we need to get rid of
	60	* it.
	61	*/
	62	rem = (fs->super->s_blocks_count - fs->super->s_first_data_block) %
	63	fs->super->s_blocks_per_group;
	64	if ((fs->group_desc_count == 1) && rem && (rem < overhead))
	65	return EXT2_ET_TOOSMALL;
	66	if (rem && (rem < overhead+50)) {
	67	fs->super->s_blocks_count -= rem;
	68	goto retry;
	69	}
	70	/*
	71	* Adjust the number of inodes
	72	*/
	73	fs->super->s_inodes_count = fs->super->s_inodes_per_group *
	74	fs->group_desc_count;
	75
	76	/*
	77	* Adjust the number of free blocks
	78	*/
	79	blk = rfs->old_fs->super->s_blocks_count;
	80	if (blk > fs->super->s_blocks_count)
	81	fs->super->s_free_blocks_count -=
	82	(blk - fs->super->s_blocks_count);
	83	else
	84	fs->super->s_free_blocks_count +=
	85	(fs->super->s_blocks_count - blk);
	86
	87	/*
	88	* Adjust the bitmaps for size
	89	*/
	90	retval = ext2fs_resize_inode_bitmap(fs->super->s_inodes_count,
	91	fs->super->s_inodes_count,
	92	fs->inode_map);
	93	if (retval)
	94	return retval;
	95
	96	real_end = ((EXT2_BLOCKS_PER_GROUP(fs->super)
	97	* fs->group_desc_count)) - 1 +
98	fs->super->s_first_data_block;
99	retval = ext2fs_resize_block_bitmap(fs->super->s_blocks_count-1,
100	real_end, fs->block_map);
101
102	if (retval)
103	return retval;
104
105	/*
106	* Reallocate the group descriptors as necessary.
107	*/
108	if (rfs->old_fs->desc_blocks != fs->desc_blocks) {
109	new = realloc(fs->group_desc,
110	fs->desc_blocks * fs->blocksize);
111	if (!new)
112	return ENOMEM;
113	fs->group_desc = new;
114	}
1e1da29f TT	115
	116	/*
	117	* Fix the count of the last (old) block group
	118	*/
	119	if (rfs->old_fs->group_desc_count > fs->group_desc_count)
	120	return 0;
	121	old_numblocks = (rfs->old_fs->super->s_blocks_count -
	122	rfs->old_fs->super->s_first_data_block) %
	123	rfs->old_fs->super->s_blocks_per_group;
	124	if (!old_numblocks)
	125	old_numblocks = rfs->old_fs->super->s_blocks_per_group;
	126	if (rfs->old_fs->group_desc_count == fs->group_desc_count) {
	127	numblocks = (rfs->new_fs->super->s_blocks_count -
	128	rfs->new_fs->super->s_first_data_block) %
	129	rfs->new_fs->super->s_blocks_per_group;
	130	if (!numblocks)
	131	numblocks = rfs->new_fs->super->s_blocks_per_group;
	132	} else
	133	numblocks = rfs->new_fs->super->s_blocks_per_group;
	134	i = rfs->old_fs->group_desc_count - 1;
	135	fs->group_desc[i].bg_free_blocks_count += (numblocks-old_numblocks);
	136
	137	/*
	138	* Initialize the new block group descriptors
	139	*/
	140	if (rfs->old_fs->group_desc_count >= fs->group_desc_count)
	141	return 0;
	142	buf = malloc(fs->blocksize);
	143	if (!buf)
	144	return ENOMEM;
	145	memset(buf, 0, fs->blocksize);
	146	group_block = fs->super->s_first_data_block +
	147	rfs->old_fs->group_desc_count * fs->super->s_blocks_per_group;
	148	for (i = rfs->old_fs->group_desc_count;
	149	i < fs->group_desc_count; i++) {
	150	memset(&fs->group_desc[i], 0,
	151	sizeof(struct ext2_group_desc));
	152	adjblocks = 0;
	153
	154	if (i == fs->group_desc_count-1) {
	155	numblocks = (fs->super->s_blocks_count -
	156	fs->super->s_first_data_block) %
	157	fs->super->s_blocks_per_group;
	158	if (!numblocks)
	159	numblocks = fs->super->s_blocks_per_group;
	160	} else
	161	numblocks = fs->super->s_blocks_per_group;
	162
	163	if (ext2fs_bg_has_super(fs, i)) {
	164	for (j=0; j < fs->desc_blocks+1; j++)
	165	ext2fs_mark_block_bitmap(fs->block_map,
	166	group_block + j);
	167	adjblocks = 1 + fs->desc_blocks;
24b2c7a7	168	}
1e1da29f TT	169	adjblocks += 2 + fs->inode_blocks_per_group;
	170
	171	numblocks -= adjblocks;
	172	fs->super->s_free_blocks_count -= adjblocks;
	173	fs->super->s_free_inodes_count +=
	174	fs->super->s_inodes_per_group;
	175	fs->group_desc[i].bg_free_blocks_count = numblocks;
	176	fs->group_desc[i].bg_free_inodes_count =
	177	fs->super->s_inodes_per_group;
	178	fs->group_desc[i].bg_used_dirs_count = 0;
24b2c7a7	179
1e1da29f TT	180	retval = ext2fs_allocate_group_table(fs, i, 0);
	181	if (retval)
	182	return retval;
24b2c7a7	183
1e1da29f TT	184	for (blk=fs->group_desc[i].bg_inode_table, j=0;
	185	j < fs->inode_blocks_per_group;
	186	blk++, j++) {
	187	retval = io_channel_write_blk(fs->io, blk, 1, buf);
	188	if (retval)
	189	return retval;
24b2c7a7	190	}
1e1da29f	191	group_block += fs->super->s_blocks_per_group;
24b2c7a7	192	}
1e1da29f	193	return 0;
24b2c7a7 TT	194	}
24b2c7a7 TT	195
24b2c7a7 TT	196	/*
	197	* This routine marks and unmarks reserved blocks in the new block
	198	* bitmap. It also determines which blocks need to be moved and
	199	* places this information into the move_blocks bitmap.
	200	*/
	201	static errcode_t determine_relocations(ext2_resize_t rfs)
	202	{
052db4b7	203	int i, j, max, adj;
24b2c7a7 TT	204	blk_t blk, group_blk;
	205	unsigned long old_blocks, new_blocks;
	206	errcode_t retval;
1e1da29f	207	ext2_filsys fs = rfs->new_fs;
24b2c7a7 TT	208
	209	retval = ext2fs_allocate_block_bitmap(rfs->old_fs,
	210	"blocks to be moved",
1e1da29f	211	&rfs->reserve_blocks);
24b2c7a7 TT	212	if (retval)
24b2c7a7 TT	213	return retval;
1e1da29f TT	214
	215	/*
	216	* If we're shrinking the filesystem, we need to move all of
	217	* the blocks that don't fit any more
	218	*/
	219	for (blk = fs->super->s_blocks_count;
	220	blk < rfs->old_fs->super->s_blocks_count; blk++) {
	221	if (ext2fs_test_block_bitmap(rfs->old_fs->block_map, blk))
	222	rfs->needed_blocks++;
	223	ext2fs_mark_block_bitmap(rfs->reserve_blocks, blk);
	224	}
24b2c7a7 TT	225
24b2c7a7 TT	226	old_blocks = rfs->old_fs->desc_blocks;
1e1da29f TT	227	new_blocks = fs->desc_blocks;
	228
	229	if (old_blocks == new_blocks)
	230	return 0;
24b2c7a7	231
052db4b7 TT	232	max = fs->group_desc_count;
	233	if (max > rfs->old_fs->group_desc_count)
	234	max = rfs->old_fs->group_desc_count;
24b2c7a7 TT	235	group_blk = rfs->old_fs->super->s_first_data_block;
	236	/*
	237	* If we're reducing the number of descriptor blocks, this
	238	* makes life easy. :-) We just have to mark some extra
	239	* blocks as free.
	240	*/
	241	if (old_blocks > new_blocks) {
052db4b7	242	for (i = 0; i < max; i++) {
1e1da29f TT	243	if (!ext2fs_bg_has_super(fs, i)) {
1e1da29f TT	244	group_blk += fs->super->s_blocks_per_group;
24b2c7a7 TT	245	continue;
	246	}
	247	for (blk = group_blk+1+old_blocks;
052db4b7	248	blk < group_blk+1+new_blocks; blk++) {
1e1da29f	249	ext2fs_unmark_block_bitmap(fs->block_map,
24b2c7a7	250	blk);
052db4b7 TT	251	rfs->needed_blocks--;
052db4b7 TT	252	}
1e1da29f	253	group_blk += fs->super->s_blocks_per_group;
24b2c7a7	254	}
1e1da29f	255	return 0;
24b2c7a7 TT	256	}
	257	/*
	258	* If we're increasing the number of descriptor blocks, life
1e1da29f	259	* gets interesting....
24b2c7a7	260	*/
052db4b7	261	for (i = 0; i < max; i++) {
1e1da29f TT	262	if (!ext2fs_bg_has_super(fs, i))
	263	goto next_group;
	264
	265	for (blk = group_blk;
	266	blk < group_blk + 1 + new_blocks; blk++) {
	267	ext2fs_mark_block_bitmap(rfs->reserve_blocks, blk);
	268	ext2fs_mark_block_bitmap(fs->block_map, blk);
	269
	270	/*
	271	* Check to see if we overlap with the inode
	272	* or block bitmap
	273	*/
052db4b7 TT	274	if (blk == fs->group_desc[i].bg_block_bitmap) {
	275	fs->group_desc[i].bg_block_bitmap = 0;
	276	rfs->needed_blocks++;
	277	}
	278	if (blk == fs->group_desc[i].bg_inode_bitmap) {
1e1da29f	279	fs->group_desc[i].bg_inode_bitmap = 0;
052db4b7 TT	280	rfs->needed_blocks++;
052db4b7 TT	281	}
1e1da29f TT	282	/*
	283	* Check to see if we overlap with the inode
	284	* table
	285	*/
	286	if (blk < fs->group_desc[i].bg_inode_table)
24b2c7a7	287	continue;
1e1da29f TT	288	if (blk >= (fs->group_desc[i].bg_inode_table +
	289	fs->inode_blocks_per_group))
	290	continue;
	291	fs->group_desc[i].bg_inode_table = 0;
	292	blk = fs->group_desc[i].bg_inode_table +
	293	fs->inode_blocks_per_group - 1;
24b2c7a7	294	}
1e1da29f TT	295	if (fs->group_desc[i].bg_inode_table &&
	296	fs->group_desc[i].bg_inode_bitmap &&
	297	fs->group_desc[i].bg_block_bitmap)
	298	goto next_group;
24b2c7a7	299
1e1da29f TT	300	/*
	301	* Allocate the missing bitmap and inode table
	302	* structures, passing in rfs->reserve_blocks to
	303	* prevent a conflict.
	304	*/
	305	if (fs->group_desc[i].bg_block_bitmap)
	306	ext2fs_mark_block_bitmap(rfs->reserve_blocks,
	307	fs->group_desc[i].bg_block_bitmap);
	308	if (fs->group_desc[i].bg_inode_bitmap)
	309	ext2fs_mark_block_bitmap(rfs->reserve_blocks,
	310	fs->group_desc[i].bg_inode_bitmap);
	311	if (fs->group_desc[i].bg_inode_table)
	312	for (blk = fs->group_desc[i].bg_inode_table, j=0;
	313	j < fs->inode_blocks_per_group ; j++, blk++)
	314	ext2fs_mark_block_bitmap(rfs->reserve_blocks,
	315	blk);
24b2c7a7	316
1e1da29f TT	317	retval = ext2fs_allocate_group_table(fs, i,
	318	rfs->reserve_blocks);
	319	if (retval)
	320	return retval;
24b2c7a7	321
1e1da29f TT	322	/*
	323	* Now make sure these blocks are reserved in the new
	324	* block bitmap
	325	*/
	326	ext2fs_mark_block_bitmap(fs->block_map,
	327	fs->group_desc[i].bg_block_bitmap);
	328	ext2fs_mark_block_bitmap(fs->block_map,
	329	fs->group_desc[i].bg_inode_bitmap);
24b2c7a7	330
052db4b7 TT	331	/*
	332	* The inode table, if we need to relocate it, is
	333	* handled specially. We have to reserve the blocks
	334	* for both the old and the new inode table, since we
	335	* can't have the inode table be destroyed during the
	336	* block relocation phase.
	337	*/
	338	adj = fs->group_desc[i].bg_inode_table -
	339	rfs->old_fs->group_desc[i].bg_inode_table;
	340	if (!adj)
	341	goto next_group; /* inode table not moved */
	342
	343	/*
	344	* Figure out how many blocks we need to have free.
	345	* This takes into account that we need to reserve
	346	* both inode tables, which may be overallping.
	347	*/
	348	if (adj < 0)
	349	adj = -adj;
	350	if (adj > fs->inode_blocks_per_group)
	351	adj = fs->inode_blocks_per_group;
	352	rfs->needed_blocks += fs->inode_blocks_per_group + adj;
	353
	354	/*
	355	* Mark the new inode table as in use in the new block
	356	* allocation bitmap.
	357	*/
1e1da29f TT	358	for (blk = fs->group_desc[i].bg_inode_table, j=0;
	359	j < fs->inode_blocks_per_group ; j++, blk++)
	360	ext2fs_mark_block_bitmap(fs->block_map, blk);
1e1da29f	361	/*
052db4b7 TT	362	* Make sure the old inode table is reserved in the
052db4b7 TT	363	* block reservation bitmap.
1e1da29f	364	*/
052db4b7 TT	365	for (blk = rfs->old_fs->group_desc[i].bg_inode_table, j=0;
	366	j < fs->inode_blocks_per_group ; j++, blk++)
	367	ext2fs_mark_block_bitmap(rfs->reserve_blocks, blk);
1e1da29f TT	368
	369	next_group:
	370	group_blk += rfs->new_fs->super->s_blocks_per_group;
	371	}
052db4b7	372	return 0;
1e1da29f	373	}
24b2c7a7 TT	374
24b2c7a7 TT	375
052db4b7 TT	376	/*
	377	* A very scary routine --- this one moves the inode table around!!!
	378	*
	379	* After this you have to use the rfs->new_fs file handle to read and
	380	* write inodes.
	381	*/
	382	errcode_t move_itables(ext2_resize_t rfs)
	383	{
	384	int i, max;
	385	ext2_filsys fs = rfs->new_fs;
	386	char *buf;
	387	blk_t old, new;
	388	errcode_t retval, err;
	389
	390	printf("Hide the women and children --- "
	391	"commencing inode table moves!!\n");
	392
	393	max = fs->group_desc_count;
	394	if (max > rfs->old_fs->group_desc_count)
	395	max = rfs->old_fs->group_desc_count;
	396
	397	buf = malloc(fs->blocksize * fs->inode_blocks_per_group);
	398	if (!buf)
	399	return ENOMEM;
	400
	401	for (i=0; i < max; i++) {
	402	old = rfs->old_fs->group_desc[i].bg_inode_table;
	403	new = fs->group_desc[i].bg_inode_table;
	404
	405	printf("Group %d block %ld->%ld\n", i, old, new);
	406
	407	if (old == new)
	408	continue;
	409
	410	retval = io_channel_read_blk(fs->io, old,
	411	fs->inode_blocks_per_group, buf);
	412	if (retval)
	413	goto backout;
	414	retval = io_channel_write_blk(fs->io, new,
	415	fs->inode_blocks_per_group, buf);
	416	if (retval) {
	417	io_channel_write_blk(fs->io, old,
	418	fs->inode_blocks_per_group, buf);
	419	goto backout;
	420	}
	421	}
	422	ext2fs_flush(rfs->new_fs);
	423	printf("Inode table move finished.\n");
	424	return 0;
	425
	426	backout:
	427	printf("Error: %s; now backing out!\n", error_message(retval));
	428	while (--i >= 0) {
	429	printf("Group %d block %ld->%ld\n", i, new, old);
	430	old = rfs->old_fs->group_desc[i].bg_inode_table;
	431	new = fs->group_desc[i].bg_inode_table;
	432
	433	err = io_channel_read_blk(fs->io, new,
	434	fs->inode_blocks_per_group, buf);
	435	if (err)
	436	continue;
	437	err = io_channel_write_blk(fs->io, old,
	438	fs->inode_blocks_per_group, buf);
	439	}
440	return retval;
441	}
442
443	/*
444	* Finally, recalculate the summary information
445	*/
446	static errcode_t ext2fs_calculate_summary_stats(ext2_filsys fs)
447	{
448	blk_t blk;
449	ino_t ino;
450	int group = 0;
451	int count = 0;
452	int total_free = 0;
453	int group_free = 0;
454
455	/*
456	* First calculate the block statistics
457	*/
458	for (blk = fs->super->s_first_data_block;
459	blk < fs->super->s_blocks_count; blk++) {
460	if (!ext2fs_fast_test_block_bitmap(fs->block_map, blk)) {
461	group_free++;
462	total_free++;
463	}
464	count++;
465	if ((count == fs->super->s_blocks_per_group) \|\|
466	(blk == fs->super->s_blocks_count-1)) {
467	fs->group_desc[group++].bg_free_blocks_count =
468	group_free;
469	count = 0;
470	group_free = 0;
471	}
472	}
473	fs->super->s_free_blocks_count = total_free;
474
475	/*
476	* Next, calculate the inode statistics
477	*/
478	group_free = 0;
479	total_free = 0;
480	count = 0;
481	group = 0;
482	for (ino = 1; ino <= fs->super->s_inodes_count; ino++) {
483	if (!ext2fs_fast_test_inode_bitmap(fs->inode_map, ino)) {
484	group_free++;
485	total_free++;
486	}
487	count++;
488	if ((count == fs->super->s_inodes_per_group) \|\|
489	(ino == fs->super->s_inodes_count)) {
490	fs->group_desc[group++].bg_free_inodes_count =
491	group_free;
492	count = 0;
493	group_free = 0;
494	}
495	}
496	fs->super->s_free_inodes_count = total_free;
497	ext2fs_mark_super_dirty(fs);
498	return 0;
499	}
500
501
502
24b2c7a7 TT	503	/*
	504	* This is the top-level routine which does the dirty deed....
	505	*/
	506	errcode_t resize_fs(ext2_filsys fs, blk_t new_size)
	507	{
	508	ext2_resize_t rfs;
	509	errcode_t retval;
	510
1e1da29f TT	511	retval = ext2fs_read_bitmaps(fs);
	512	if (retval)
	513	return retval;
	514
24b2c7a7	515	/*
1e1da29f	516	* Create the data structure
24b2c7a7 TT	517	*/
	518	rfs = malloc(sizeof(struct ext2_resize_struct));
	519	if (!rfs)
	520	return ENOMEM;
	521	memset(rfs, 0, sizeof(struct ext2_resize_struct));
	522
	523	rfs->old_fs = fs;
	524	retval = ext2fs_dup_handle(fs, &rfs->new_fs);
1e1da29f TT	525	if (retval)
	526	goto errout;
	527
24b2c7a7 TT	528	retval = adjust_superblock(rfs, new_size);
	529	if (retval)
	530	goto errout;
1e1da29f TT	531
	532	retval = determine_relocations(rfs);
	533	if (retval)
	534	goto errout;
	535
052db4b7 TT	536	printf("Number of free blocks: %d, Needed: %d\n",
	537	fs->super->s_free_blocks_count, rfs->needed_blocks);
	538
	539	if (rfs->needed_blocks > fs->super->s_free_blocks_count) {
	540	retval = ENOSPC;
	541	goto errout;
	542	}
	543
1e1da29f TT	544	printf("\nOld superblock:\n");
	545	list_super(rfs->old_fs->super);
	546	printf("\n\nNew superblock:\n");
	547	list_super(rfs->new_fs->super);
	548	printf("\n");
	549
	550	retval = ext2fs_move_blocks(rfs->old_fs, rfs->reserve_blocks,
052db4b7	551	rfs->new_fs->block_map,
1e1da29f	552	EXT2_BMOVE_GET_DBLIST);
052db4b7 TT	553	if (retval)
052db4b7 TT	554	return retval;
1e1da29f	555
052db4b7 TT	556	retval = ext2fs_inode_move(rfs);
	557	if (retval)
	558	return retval;
	559
	560	retval = move_itables(rfs);
	561	if (retval)
	562	return retval;
	563
	564	retval = ext2fs_calculate_summary_stats(rfs->new_fs);
	565	if (retval)
	566	return retval;
	567
1e1da29f TT	568	retval = ext2fs_close(rfs->new_fs);
	569	if (retval)
	570	return retval;
	571
	572	ext2fs_free(rfs->old_fs);
24b2c7a7 TT	573
	574	return 0;
	575
	576	errout:
1e1da29f TT	577	if (rfs->new_fs)
1e1da29f TT	578	ext2fs_free(rfs->new_fs);
24b2c7a7 TT	579	free(rfs);
	580	return retval;
	581	}