[PATCH v8 8/9] ext4: call dax_pfn_mkwrite() for DAX fsync/msync

[Ross Zwisler]

To properly support the new DAX fsync/msync infrastructure filesystems
need to call dax_pfn_mkwrite() so that DAX can track when user pages are
dirtied.

Signed-off-by: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>
Reviewed-by: Jan Kara <jack@xxxxxxx>
---
 fs/ext4/file.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index 60683ab..fa899c9 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -291,8 +291,8 @@ static int ext4_dax_pfn_mkwrite(struct vm_area_struct *vma,
 {
 	struct inode *inode = file_inode(vma->vm_file);
 	struct super_block *sb = inode->i_sb;
-	int ret = VM_FAULT_NOPAGE;
 	loff_t size;
+	int ret;
 
 	sb_start_pagefault(sb);
 	file_update_time(vma->vm_file);
@@ -300,6 +300,8 @@ static int ext4_dax_pfn_mkwrite(struct vm_area_struct *vma,
 	size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT;
 	if (vmf->pgoff >= size)
 		ret = VM_FAULT_SIGBUS;
+	else
+		ret = dax_pfn_mkwrite(vma, vmf);
 	up_read(&EXT4_I(inode)->i_mmap_sem);
 	sb_end_pagefault(sb);
 
-- 
2.5.0