Make XFS use block_page_mkwrite

Index: 2.6.x-xfs-new/fs/xfs/linux-2.6/xfs_file.c
===================================================================
@@ -446,6 +446,20 @@ xfs_file_open_exec(
 }
 #endif /* HAVE_FOP_OPEN_EXEC */
 
+/*
+ * mmap()d file has taken write protection fault and is being made
+ * writable. We can set the page state up correctly for a writable
+ * page, which means we can do correct delalloc accounting (ENOSPC
+ * checking!) and unwritten extent mapping.
+ */
+STATIC int
+xfs_vm_page_mkwrite(
+	struct vm_area_struct	*vma,
+	struct page		*page)
+{
+	return block_page_mkwrite(vma, page, xfs_get_blocks);
+}
+
 const struct file_operations xfs_file_operations = {
 	.llseek		= generic_file_llseek,
 	.read		= do_sync_read,

@@ -503,12 +517,14 @@ const struct file_operations xfs_dir_fil
 static struct vm_operations_struct xfs_file_vm_ops = {
 	.nopage		= filemap_nopage,
 	.populate	= filemap_populate,
+	.page_mkwrite	= xfs_vm_page_mkwrite,
 };
 
 #ifdef HAVE_DMAPI
 static struct vm_operations_struct xfs_dmapi_file_vm_ops = {
 	.nopage		= xfs_vm_nopage,
 	.populate	= filemap_populate,
+	.page_mkwrite	= xfs_vm_page_mkwrite,
 #ifdef HAVE_VMOP_MPROTECT
 	.mprotect	= xfs_vm_mprotect,
 #endif