cifs: revalidate mapping when doing direct writes

Kernel bugzilla: 216301

When doing direct writes we need to also invalidate the mapping in case
we have a cached copy of the affected page(s) in memory or else
subsequent reads of the data might return the old/stale content
before we wrote an update to the server.

Cc: [email protected]
Reviewed-by: Paulo Alcantara (SUSE) <[email protected]>
Signed-off-by: Ronnie Sahlberg <[email protected]>
Signed-off-by: Steve French <[email protected]>

Author: Ronnie Sahlberg

fs/cifs/file.c

@@ -3575,6 +3575,9 @@ static ssize_t __cifs_writev(
 
 ssize_t cifs_direct_writev(struct kiocb *iocb, struct iov_iter *from)
 {
+	struct file *file = iocb->ki_filp;
+
+	cifs_revalidate_mapping(file->f_inode);
 	return __cifs_writev(iocb, from, true);
 }