path: root/fs/ext3/resize.c

/*
 *  linux/fs/ext3/resize.c
 *
 * Support for resizing an ext3 filesystem while it is mounted.
 *
 * Copyright (C) 2001, 2002 Andreas Dilger <adilger@clusterfs.com>
 *
 * This could probably be made into a module, because it is not often in use.
 */


#define EXT3FS_DEBUG

#include <linux/smp_lock.h>
#include <linux/ext3_jbd.h>

#include <linux/errno.h>
#include <linux/slab.h>


#define outside(b, first, last)	((b) < (first) || (b) >= (last))
#define inside(b, first, last)	((b) >= (first) && (b) < (last))

static int verify_group_input(struct super_block *sb,
			      struct ext3_new_group_data *input)
{
	struct ext3_sb_info *sbi = EXT3_SB(sb);
	struct ext3_super_block *es = sbi->s_es;
	ext3_fsblk_t start = le32_to_cpu(es->s_blocks_count);
	ext3_fsblk_t end = start + input->blocks_count;
	unsigned group = input->group;
	ext3_fsblk_t itend = input->inode_table + sbi->s_itb_per_group;
	unsigned overhead = ext3_bg_has_super(sb, group) ?
		(1 + ext3_bg_num_gdb(sb, group) +
		 le16_to_cpu(es->s_reserved_gdt_blocks)) : 0;
	ext3_fsblk_t metaend = start + overhead;
	struct buffer_head *bh = NULL;
	ext3_grpblk_t free_blocks_count;
	int err = -EINVAL;

	input->free_blocks_count = free_blocks_count =
		input->blocks_count - 2 - overhead - sbi->s_itb_per_group;

	if (test_opt(sb, DEBUG))
		printk(KERN_DEBUG "EXT3-fs: adding %s group %u: %u blocks "
		       "(%d free, %u reserved)\n",
		       ext3_bg_has_super(sb, input->group) ? "normal" :
		       "no-super", input->group, input->blocks_count,
		       free_blocks_count, input->reserved_blocks);

	if (group != sbi->s_groups_count)
		ext3_warning(sb, __FUNCTION__,
			     "Cannot add at group %u (only %lu groups)",
			     input->group, sbi->s_groups_count);
	else if ((start - le32_to_cpu(es->s_first_data_block)) %
		 EXT3_BLOCKS_PER_GROUP(sb))
		ext3_warning(sb, __FUNCTION__, "Last group not full");
	else if (input->reserved_blocks > input->blocks_count / 5)
		ext3_warning(sb, __FUNCTION__, "Reserved blocks too high (%u)",
			     input->reserved_blocks);
	else if (free_blocks_count < 0)
		ext3_warning(sb, __FUNCTION__, "Bad blocks count %u",
			     input->blocks_count);
	else if (!(bh = sb_bread(sb, end - 1)))
		ext3_warning(sb, __FUNCTION__,
			     "Cannot read last block ("E3FSBLK")",
			     end - 1);
	else if (outside(input->block_bitmap, start, end))
		ext3_warning(sb, __FUNCTION__,
			     "Block bitmap not in group (block %u)",
			     input->block_bitmap);
	else if (outside(input->inode_bitmap, start, end))
		ext3_warning(sb, __FUNCTION__,
			     "Inode bitmap not in group (block %u)",
			     input->inode_bitmap);
	else if (outside(input->inode_table, start, end) ||
	         outside(itend - 1, start, end))
		ext3_warning(sb, __FUNCTION__,
			     "Inode table not in group (blocks %u-"E3FSBLK")",
			     input->inode_table, itend - 1);
	else if (input->inode_bitmap == input->block_bitmap)
		ext3_warning(sb, __FUNCTION__,
			     "Block bitmap same as inode bitmap (%u)",
			     input->block_bitmap);
	else if (inside(input->block_bitmap, input->inode_table, itend))
		ext3_warning(sb, __FUNCTION__,
			     "Block bitmap (%u) in inode table (%u-"E3FSBLK")",
			     input->block_bitmap, input->inode_table, itend-1);
	else if (inside(input->inode_bitmap, input->inode_table, itend))
		ext3_warning(sb, __FUNCTION__,
			     "Inode bitmap (%u) in inode table (%u-"E3FSBLK")",
			     input->inode_bitmap, input->inode_table, itend-1);
	else if (inside(input->block_bitmap, start, metaend))
		ext3_warning(sb, __FUNCTION__,
			     "Block bitmap (%u) in GDT table"
			     " ("E3FSBLK"-"E3FSBLK")",
			     input->block_bitmap, start