ocfs2: temporarily remove extent map caching

The code in extent_map.c is not prepared to deal with a subtree being
rotated between lookups. This can happen when filling holes in sparse files.
Instead of a lengthy patch to update the code (which would likely lose the
benefit of caching subtree roots), we remove most of the algorithms and
implement a simple path based lookup. A less ambitious extent caching scheme
will be added in a later patch.

Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
index 875c114..f3b0cc5 100644
--- a/fs/ocfs2/aops.c
+++ b/fs/ocfs2/aops.c
@@ -158,8 +158,7 @@
 	if (err)
 		goto bail;
 
-	err = ocfs2_extent_map_get_blocks(inode, iblock, 1, &p_blkno,
-					  NULL);
+	err = ocfs2_extent_map_get_blocks(inode, iblock, &p_blkno, NULL);
 	if (err) {
 		mlog(ML_ERROR, "Error %d from get_blocks(0x%p, %llu, 1, "
 		     "%llu, NULL)\n", err, inode, (unsigned long long)iblock,
@@ -499,8 +498,7 @@
 		down_read(&OCFS2_I(inode)->ip_alloc_sem);
 	}
 
-	err = ocfs2_extent_map_get_blocks(inode, block, 1, &p_blkno,
-					  NULL);
+	err = ocfs2_extent_map_get_blocks(inode, block, &p_blkno, NULL);
 
 	if (!INODE_JOURNAL(inode)) {
 		up_read(&OCFS2_I(inode)->ip_alloc_sem);
@@ -574,7 +572,7 @@
 
 	/* This figures out the size of the next contiguous block, and
 	 * our logical offset */
-	ret = ocfs2_extent_map_get_blocks(inode, iblock, 1, &p_blkno,
+	ret = ocfs2_extent_map_get_blocks(inode, iblock, &p_blkno,
 					  &contig_blocks);
 	if (ret) {
 		mlog(ML_ERROR, "get_blocks() failed iblock=%llu\n",