ocfs2: Change ocfs2_get_*_extent_tree() to ocfs2_init_*_extent_tree()

The original get/put_extent_tree() functions held a reference on
et_root_bh.  However, every single caller already has a safe reference,
making the get/put cycle irrelevant.

We change ocfs2_get_*_extent_tree() to ocfs2_init_*_extent_tree().  It
no longer gets a reference on et_root_bh.  ocfs2_put_extent_tree() is
removed.  Callers now have a simpler init+use pattern.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
index ed937fa..259775e 100644
--- a/fs/ocfs2/aops.c
+++ b/fs/ocfs2/aops.c
@@ -1277,11 +1277,10 @@
 			goto out;
 		}
 	} else if (unwritten) {
-		ocfs2_get_dinode_extent_tree(&et, inode, wc->w_di_bh);
+		ocfs2_init_dinode_extent_tree(&et, inode, wc->w_di_bh);
 		ret = ocfs2_mark_extent_written(inode, &et,
 						wc->w_handle, cpos, 1, phys,
 						meta_ac, &wc->w_dealloc);
-		ocfs2_put_extent_tree(&et);
 		if (ret < 0) {
 			mlog_errno(ret);
 			goto out;
@@ -1722,11 +1721,10 @@
 		     (long long)i_size_read(inode), le32_to_cpu(di->i_clusters),
 		     clusters_to_alloc, extents_to_split);
 
-		ocfs2_get_dinode_extent_tree(&et, inode, wc->w_di_bh);
+		ocfs2_init_dinode_extent_tree(&et, inode, wc->w_di_bh);
 		ret = ocfs2_lock_allocators(inode, &et,
 					    clusters_to_alloc, extents_to_split,
 					    &data_ac, &meta_ac);
-		ocfs2_put_extent_tree(&et);
 		if (ret) {
 			mlog_errno(ret);
 			goto out;