[PATCH 5.4 012/120] cifs: revalidate mapping when doing direct writes

[Greg Kroah-Hartman]

From: Ronnie Sahlberg <lsahlber@xxxxxxxxxx>

commit 7500a99281dfed2d4a84771c933bcb9e17af279b upstream.

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: stable@xxxxxxxxxxxxxxx
Reviewed-by: Paulo Alcantara (SUSE) <pc@xxxxxx>
Signed-off-by: Ronnie Sahlberg <lsahlber@xxxxxxxxxx>
Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 fs/cifs/file.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -3194,6 +3194,9 @@ 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);
 }