diff --git a/fs/xfs/linux-2.6/xfs_file.c b/fs/xfs/linux-2.6/xfs_file.c
index cbcd40c..b4c9364 100644
--- a/fs/xfs/linux-2.6/xfs_file.c
+++ b/fs/xfs/linux-2.6/xfs_file.c
@@ -413,6 +413,20 @@
 }
 #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,
@@ -466,12 +480,14 @@
 static struct vm_operations_struct xfs_file_vm_ops = {
 	.nopage		= filemap_nopage,
 	.populate	= filemap_populate,
+	.page_mkwrite	= xfs_vm_page_mkwrite,
 };
 
 #ifdef CONFIG_XFS_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