more ext3 16T overflow fixes

Some of the changes in balloc.c are just cosmetic, as Andreas pointed out - if they overflow they'll then underflow and things are fine.

5th hunk actually fixes an overflow problem.

Also check for potential overflows in inode & block counts when resizing.

Index: linux-2.6.17/fs/ext3/balloc.c
===================================================================
@@ -168,7 +168,7 @@ goal_in_my_reservation(struct ext3_reser

	ext3_fsblk_t group_first_block, group_last_block;

	group_first_block = ext3_group_first_block_no(sb, group);

- group_last_block = group_first_block + EXT3_BLOCKS_PER_GROUP(sb) - 1;
+ group_last_block = group_first_block + (EXT3_BLOCKS_PER_GROUP(sb) - 1);

	if ((rsv->_rsv_start > group_last_block) ||
	    (rsv->_rsv_end < group_first_block))
@@ -897,7 +897,7 @@ static int alloc_new_reservation(struct 
	spinlock_t *rsv_lock = &EXT3_SB(sb)->s_rsv_window_lock;

	group_first_block = ext3_group_first_block_no(sb, group);

- group_end_block = group_first_block + EXT3_BLOCKS_PER_GROUP(sb) - 1;
+ group_end_block = group_first_block + (EXT3_BLOCKS_PER_GROUP(sb) - 1);

	if (grp_goal < 0)
		start_block = group_first_block;

@@ -1063,7 +1063,7 @@ ext3_try_to_allocate_with_rsv(struct sup
struct ext3_reserve_window_node * my_rsv, unsigned long *count, int *errp)
{
- ext3_fsblk_t group_first_block;

+	ext3_fsblk_t group_first_block, group_last_block;
	ext3_grpblk_t ret = 0;
	int fatal;
	unsigned long num = *count;
@@ -1100,6 +1100,7 @@ ext3_try_to_allocate_with_rsv(struct sup
	 * first block is the block number of the first block in this group
	 */
	group_first_block = ext3_group_first_block_no(sb, group);

+ group_last_block = group_first_block + (EXT3_BLOCKS_PER_GROUP(sb) - 1);

	/*
	 * Basically we will allocate a new block from inode's reservation
@@ -1132,7 +1133,7 @@ ext3_try_to_allocate_with_rsv(struct sup
			try_to_extend_reservation(my_rsv, sb,
					*count-my_rsv->rsv_end + grp_goal - 1);

- if ((my_rsv->rsv_start >= group_first_block + EXT3_BLOCKS_PER_GROUP(sb))
+ if ((my_rsv->rsv_start > group_last_block)

		    || (my_rsv->rsv_end < group_first_block))
			BUG();
		ret = ext3_try_to_allocate(sb, handle, group, bitmap_bh, grp_goal,

Index: linux-2.6.17/fs/ext3/resize.c
===================================================================
@@ -730,6 +730,16 @@ int ext3_group_add(struct super_block *s

		return -EPERM;
	}

+ if (es->s_blocks_count + input->blocks_count < es->s_blocks_count) {
+ ext3_warning(sb, __FUNCTION__, "blocks_count overflow\n");
+ return -EINVAL;
+ }
+
+ if (es->s_inodes_count+EXT3_INODES_PER_GROUP(sb) < es->s_inodes_count) {
+ ext3_warning(sb, __FUNCTION__, "inodes_count overflow\n");
+ return -EINVAL;
+ }
+

	if (reserved_gdb || gdb_off == 0) {
		if (!EXT3_HAS_COMPAT_FEATURE(sb,
					     EXT3_FEATURE_COMPAT_RESIZE_INODE)){

@@ -958,6 +968,11 @@ int ext3_group_extend(struct super_block

	add = EXT3_BLOCKS_PER_GROUP(sb) - last;

+ if (o_blocks_count + add < o_blocks_count) {
+ ext3_warning(sb, __FUNCTION__, "blocks_count overflow");
+ return -EINVAL;
+ }
+

	if (o_blocks_count + add > n_blocks_count)
		add = n_blocks_count - o_blocks_count;