diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 4496b45..4827e82 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -44,6 +44,7 @@
 #include <linux/falloc.h>
 #include <linux/pagevec.h>
 #include <linux/backing-dev.h>
+#include <linux/mman.h>
 
 static const struct vm_operations_struct xfs_file_vm_ops;
 
@@ -1040,7 +1041,11 @@ __xfs_filemap_fault(
 
 	xfs_ilock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
 	if (IS_DAX(inode)) {
-		ret = dax_iomap_fault(vmf, pe_size, NULL, &xfs_iomap_ops);
+		pfn_t pfn;
+
+		ret = dax_iomap_fault(vmf, pe_size, &pfn, &xfs_iomap_ops);
+		if (ret & VM_FAULT_NEEDDSYNC)
+			ret = dax_finish_sync_fault(vmf, pe_size, pfn);
 	} else {
 		if (write_fault)
 			ret = iomap_page_mkwrite(vmf, &xfs_iomap_ops);
@@ -1110,6 +1115,13 @@ xfs_file_mmap(
 	struct file	*filp,
 	struct vm_area_struct *vma)
 {
+	/*
+	 * We don't support synchronous mappings for non-DAX files. At least
+	 * until someone comes with a sensible use case.
+	 */
+	if (!IS_DAX(file_inode(filp)) && (vma->vm_flags & VM_SYNC))
+		return -EOPNOTSUPP;
+
 	file_accessed(filp);
 	vma->vm_ops = &xfs_file_vm_ops;
 	if (IS_DAX(file_inode(filp)))
@@ -1128,6 +1140,7 @@ const struct file_operations xfs_file_operations = {
 	.compat_ioctl	= xfs_file_compat_ioctl,
 #endif
 	.mmap		= xfs_file_mmap,
+	.mmap_supported_flags = MAP_SYNC,
 	.open		= xfs_file_open,
 	.release	= xfs_file_release,
 	.fsync		= xfs_file_fsync,