[PATCH 4.14 087/165] smb3: Do not send SMB3 SET_INFO if nothing changed

From: Greg Kroah-Hartman
Date: Mon Sep 03 2018 - 13:22:44 EST


4.14-stable review patch. If anyone has any objections, please let me know.

------------------

From: Steve French <stfrench@xxxxxxxxxxxxx>

commit fd09b7d3b352105f08b8e02f7afecf7e816380ef upstream.

An earlier commit had a typo which prevented the
optimization from working:

commit 18dd8e1a65dd ("Do not send SMB3 SET_INFO request if nothing is changing")

Thank you to Metze for noticing this. Also clear a
reserved field in the FILE_BASIC_INFO struct we send
that should be zero (all the other fields in that
struct were set or cleared explicitly already in
cifs_set_file_info).

Reviewed-by: Pavel Shilovsky <pshilov@xxxxxxxxxxxxx>
CC: Stable <stable@xxxxxxxxxxxxxxx> # 4.9.x+
Reported-by: Stefan Metzmacher <metze@xxxxxxxxx>
Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
fs/cifs/inode.c | 2 ++
fs/cifs/smb2inode.c | 2 +-
2 files changed, 3 insertions(+), 1 deletion(-)

--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -1122,6 +1122,8 @@ cifs_set_file_info(struct inode *inode,
if (!server->ops->set_file_info)
return -ENOSYS;

+ info_buf.Pad = 0;
+
if (attrs->ia_valid & ATTR_ATIME) {
set_time = true;
info_buf.LastAccessTime =
--- a/fs/cifs/smb2inode.c
+++ b/fs/cifs/smb2inode.c
@@ -267,7 +267,7 @@ smb2_set_file_info(struct inode *inode,
int rc;

if ((buf->CreationTime == 0) && (buf->LastAccessTime == 0) &&
- (buf->LastWriteTime == 0) && (buf->ChangeTime) &&
+ (buf->LastWriteTime == 0) && (buf->ChangeTime == 0) &&
(buf->Attributes == 0))
return 0; /* would be a no op, no sense sending this */