ocfs2: move nonsparse hole-filling into ocfs2_write_begin()

By doing this, we can remove any higher level logic which has to have
knowledge of btree functionality - any callers of ocfs2_write_begin() can
now expect it to do anything necessary to prepare the inode for new data.

Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
Reviewed-by: Joel Becker <joel.becker@oracle.com>
diff --git a/fs/ocfs2/file.h b/fs/ocfs2/file.h
index 36fe27f..066f14a 100644
--- a/fs/ocfs2/file.h
+++ b/fs/ocfs2/file.h
@@ -47,6 +47,8 @@
 			       struct ocfs2_alloc_context *data_ac,
 			       struct ocfs2_alloc_context *meta_ac,
 			       enum ocfs2_alloc_restarted *reason_ret);
+int ocfs2_extend_no_holes(struct inode *inode, u64 new_i_size,
+			  u64 zero_to);
 int ocfs2_lock_allocators(struct inode *inode, struct ocfs2_dinode *di,
 			  u32 clusters_to_add, u32 extents_to_split,
 			  struct ocfs2_alloc_context **data_ac,