Ocfs2: Make ocfs2_find_cpos_for_left_leaf() public.

The original idea to pull ocfs2_find_cpos_for_left_leaf() out of
alloc.c is to benefit punching-holes optimization patch, it however,
can also be referred by other funcs in the future who want to do the
same job.

Signed-off-by: Tristan Ye <tristan.ye@oracle.com>
Acked-by: Mark Fasheh <mfasheh@suse.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
diff --git a/fs/ocfs2/alloc.c b/fs/ocfs2/alloc.c
index 0cb4248..7e9cb75 100644
--- a/fs/ocfs2/alloc.c
+++ b/fs/ocfs2/alloc.c
@@ -2209,8 +2209,8 @@
  *
  * Will return zero if the path passed in is already the leftmost path.
  */
-static int ocfs2_find_cpos_for_left_leaf(struct super_block *sb,
-					 struct ocfs2_path *path, u32 *cpos)
+int ocfs2_find_cpos_for_left_leaf(struct super_block *sb,
+				  struct ocfs2_path *path, u32 *cpos)
 {
 	int i, j, ret = 0;
 	u64 blkno;