--- /dev/null
+Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
+Signed-off-by: Andreas Dilger <adilger@clusterfs.com>
+Index: linux-2.6.9/fs/ext3/balloc.c
+===================================================================
+--- linux-2.6.9.orig/fs/ext3/balloc.c
++++ linux-2.6.9/fs/ext3/balloc.c
+@@ -143,6 +143,14 @@ unsigned ext3_init_block_bitmap(struct s
+ return free_blocks - sbi->s_itb_per_group - 2;
+ }
+
++static inline int
++block_in_use(unsigned long block, struct super_block *sb, unsigned char *map)
++{
++ return ext3_test_bit ((block -
++ le32_to_cpu(EXT3_SB(sb)->s_es->s_first_data_block)) %
++ EXT3_BLOCKS_PER_GROUP(sb), map);
++}
++
+ /*
+ * Read the bitmap for a given block_group, reading into the specified
+ * slot in the superblock's bitmap cache.
+@@ -152,14 +160,18 @@ unsigned ext3_init_block_bitmap(struct s
+ struct buffer_head *
+ read_block_bitmap(struct super_block *sb, unsigned int block_group)
+ {
++ int i;
+ struct ext3_group_desc * desc;
+ struct buffer_head * bh = NULL;
++ unsigned long bitmap_blk;
+
+ desc = ext3_get_group_desc (sb, block_group, NULL);
+ if (!desc)
+- goto error_out;
++ return NULL;
++
++ bitmap_blk = le32_to_cpu(desc->bg_block_bitmap);
+ if (desc->bg_flags & cpu_to_le16(EXT3_BG_BLOCK_UNINIT)) {
+- bh = sb_getblk(sb, le32_to_cpu(desc->bg_block_bitmap));
++ bh = sb_getblk(sb, bitmap_blk);
+ if (!buffer_uptodate(bh)) {
+ lock_buffer(bh);
+ if (!buffer_uptodate(bh)) {
+@@ -169,15 +181,44 @@ read_block_bitmap(struct super_block *sb
+ unlock_buffer(bh);
+ }
+ } else {
+- bh = sb_bread(sb, le32_to_cpu(desc->bg_block_bitmap));
++ bh = sb_bread(sb, bitmap_blk);
+ }
+ if (!bh)
+- ext3_error (sb, "read_block_bitmap",
++ ext3_error (sb, __FUNCTION__,
+ "Cannot read block bitmap - "
+- "block_group = %d, block_bitmap = %u",
+- block_group, le32_to_cpu(desc->bg_block_bitmap));
+-error_out:
++ "block_group = %d, block_bitmap = %lu",
++ block_group, bitmap_blk);
++
++ /* check whether block bitmap block number is set */
++ if (!block_in_use(bitmap_blk, sb, bh->b_data)) {
++ /* bad block bitmap */
++ goto error_out;
++ }
++
++ /* check whether the inode bitmap block number is set */
++ bitmap_blk = le32_to_cpu(desc->bg_inode_bitmap);
++ if (!block_in_use(bitmap_blk, sb, bh->b_data)) {
++ /* bad block bitmap */
++ goto error_out;
++ }
++ /* check whether the inode table block number is set */
++ bitmap_blk = le32_to_cpu(desc->bg_inode_table);
++ for (i = 0; i < EXT3_SB(sb)->s_itb_per_group; i++, bitmap_blk++) {
++ if (!block_in_use(bitmap_blk, sb, bh->b_data)) {
++ /* bad block bitmap */
++ goto error_out;
++ }
++ }
+ return bh;
++
++error_out:
++ brelse(bh);
++ ext3_error(sb, __FUNCTION__,
++ "Invalid block bitmap - "
++ "block_group = %d, block = %lu",
++ block_group, bitmap_blk);
++ return NULL;
++
+ }
+ /*
+ * The reservation window structure operations
+@@ -1501,15 +1542,6 @@ unsigned long ext3_count_free_blocks(str
+ #endif
+ }
+
+-static inline int block_in_use(unsigned long block,
+- struct super_block * sb,
+- unsigned char * map)
+-{
+- return ext3_test_bit ((block -
+- le32_to_cpu(EXT3_SB(sb)->s_es->s_first_data_block)) %
+- EXT3_BLOCKS_PER_GROUP(sb), map);
+-}
+-
+ static inline int test_root(int a, int b)
+ {
+ if (a == 0)