On Aug 18, 2008  22:21 +0530, Aneesh Kumar wrote:

quoted

+static int ext2_block_in_group(struct super_block *sb,
+			unsigned int block_group, ext2_fsblk_t block)
+{
+	if (block < ext2_group_first_block_no(sb, block_group))
+		return 0;
+	if (block >= ext2_group_first_block_no(sb, block_group) +
+	    EXT2_BLOCKS_PER_GROUP(sb))
+		return 0;
+	return 1;
+}
+
 /*
  * Read the bitmap for a given block_group,and validate the
  * bits for block/inode/inode tables are set in the bitmaps

@@ -129,6 +140,24 @@ read_block_bitmap(struct super_block *sb, unsigned int block_group)
 	desc = ext2_get_group_desc(sb, block_group, NULL);
 	if (!desc)
 		return NULL;
+	if (!ext2_block_in_group(sb, block_group,
+				le32_to_cpu(desc->bg_block_bitmap)) ||
+	    !ext2_block_in_group(sb, block_group,
+				le32_to_cpu(desc->bg_inode_bitmap)) ||
+	    !ext2_block_in_group(sb, block_group,
+				le32_to_cpu(desc->bg_inode_table)) ||
+	    !ext2_block_in_group(sb, block_group,
+				le32_to_cpu(desc->bg_inode_table) +
+				EXT2_SB(sb)->s_itb_per_group - 1)) {

Isn't equivalent checking done in ext2_check_descriptors()?  It would make
sense to abstract out the "check one group and return error" code and use
it in both places.

Cheers, Andreas
--
Andreas Dilger
Sr. Staff Engineer, Lustre Group
Sun Microsystems of Canada, Inc.