[PATCH 4.18 012/123] smb3: Do not send SMB3 SET_INFO if nothing changed

[Greg Kroah-Hartman]

4.18-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
@@ -283,7 +283,7 @@ 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 */