ocfs2: Fix extent lookup to return true size of holes

Initially, we had wired things to return a size '1' of holes. Cook up a
small amount of code to find the next extent and calculate the number of
clusters between the virtual offset and the next allocated extent.

Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
index eb67c90..ff71e0b 100644
--- a/fs/ocfs2/aops.c
+++ b/fs/ocfs2/aops.c
@@ -439,8 +439,7 @@
 				     struct buffer_head *bh_result, int create)
 {
 	int ret;
-	u64 p_blkno, inode_blocks;
-	int contig_blocks;
+	u64 p_blkno, inode_blocks, contig_blocks;
 	unsigned int ext_flags;
 	unsigned char blocksize_bits = inode->i_sb->s_blocksize_bits;
 	unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits;