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>

fs/ocfs2/slot_map.c

@@ -197,7 +197,7 @@ int ocfs2_init_slot_info(struct ocfs2_super *osb)
 		goto bail;
 	}
 
-	status = ocfs2_extent_map_get_blocks(inode, 0ULL, 1, &blkno, NULL);
+	status = ocfs2_extent_map_get_blocks(inode, 0ULL, &blkno, NULL);
 	if (status < 0) {
 		mlog_errno(status);
 		goto bail;