[PATCH] xfs: add ->pfn_mkwrite support for DAX

[Dave Chinner]

From: Dave Chinner <dchinner at redhat.com>

->pfn_mkwrite support is needed so that when a page with allocated
backing store first takes a write fault the timestamps on the
file are updated. THis fixes a generic/080 failure.

Signed-off-by: Dave Chinner <dchinner at redhat.com>
---
 fs/xfs/xfs_file.c  | 11 +++++++++++
 fs/xfs/xfs_trace.h |  1 +
 2 files changed, 12 insertions(+)

diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index de2c237..26535ba 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -1546,10 +1546,21 @@ xfs_filemap_fault(
 	return ret;
 }
 
+static int
+xfs_filemap_pfn_mkwrite(
+	struct vm_area_struct	*vma,
+	struct vm_fault		*vmf)
+{
+	trace_xfs_filemap_pfn_mkwrite(XFS_I(file_inode(vma->vm_file)));
+
+	return dax_pfn_mkwrite(vma, vmf);
+}
+
 static const struct vm_operations_struct xfs_file_vm_ops = {
 	.fault		= xfs_filemap_fault,
 	.map_pages	= filemap_map_pages,
 	.page_mkwrite	= xfs_filemap_page_mkwrite,
+	.pfn_mkwrite	= xfs_filemap_pfn_mkwrite,
 };
 
 STATIC int
diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
index 8b5432e..63d87f2 100644
--- a/fs/xfs/xfs_trace.h
+++ b/fs/xfs/xfs_trace.h
@@ -688,6 +688,7 @@ DEFINE_INODE_EVENT(xfs_inode_free_eofblocks_invalid);
 
 DEFINE_INODE_EVENT(xfs_filemap_fault);
 DEFINE_INODE_EVENT(xfs_filemap_page_mkwrite);
+DEFINE_INODE_EVENT(xfs_filemap_pfn_mkwrite);
 
 DECLARE_EVENT_CLASS(xfs_iref_class,
 	TP_PROTO(struct xfs_inode *ip, unsigned long caller_ip),
-- 
2.5.0