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

[Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>]

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