Do not send SMB3 SET_INFO request if nothing is changing

[CIFS] We had cases where we sent a SMB2/SMB3 setinfo request with all
timestamp (and DOS attribute) fields marked as 0 (ie do not change)
e.g. on chmod or chown.

Signed-off-by: Steve French <steve.french@primarydata.com>
CC: Stable <stable@vger.kernel.org>

1 files changed, 6 insertions, 0 deletions

diff --git a/fs/cifs/smb2inode.c b/fs/cifs/smb2inode.c
index 4f0231e685a9..1238cd3552f9 100644
--- a/fs/cifs/smb2inode.c
+++ b/fs/cifs/smb2inode.c
@@ -266,9 +266,15 @@ smb2_set_file_info(struct inode *inode, const char *full_path,
         struct tcon_link *tlink;
         int rc;
 
+        if ((buf->CreationTime == 0) && (buf->LastAccessTime == 0) &&
+            (buf->LastWriteTime == 0) && (buf->ChangeTime) &&
+            (buf->Attributes == 0))
+                return 0; /* would be a no op, no sense sending this */
+
         tlink = cifs_sb_tlink(cifs_sb);
         if (IS_ERR(tlink))
                 return PTR_ERR(tlink);
+
         rc = smb2_open_op_close(xid, tlink_tcon(tlink), cifs_sb, full_path,
                                 FILE_WRITE_ATTRIBUTES, FILE_OPEN, 0, buf,
                                 SMB2_OP_SET_INFO);