cifs: copy_file_range needs to strip setuid bits and update timestamps

cifs has both source and destination inodes locked throughout the copy.
Like ->write_iter(), we update mtime and strip setuid bits of destination
file before copy and like ->read_iter(), we update atime of source file
after copy.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/cifs/cifsfs.c

@@ -1104,6 +1104,10 @@ ssize_t cifs_file_copychunk_range(unsigned int xid,
 		goto out;
 	}
 
+	rc = -EOPNOTSUPP;
+	if (!target_tcon->ses->server->ops->copychunk_range)
+		goto out;
+
 	/*
 	 * Note: cifs case is easier than btrfs since server responsible for
 	 * checks for proper open modes and file type and if it wants
@@ -1115,11 +1119,12 @@ ssize_t cifs_file_copychunk_range(unsigned int xid,
 	/* should we flush first and last page first */
 	truncate_inode_pages(&target_inode->i_data, 0);
 
-	if (target_tcon->ses->server->ops->copychunk_range)
+	rc = file_modified(dst_file);
+	if (!rc)
 		rc = target_tcon->ses->server->ops->copychunk_range(xid,
 			smb_file_src, smb_file_target, off, len, destoff);
-	else
-		rc = -EOPNOTSUPP;
+
+	file_accessed(src_file);
 
 	/* force revalidate of size and timestamps of target file now
 	 * that target is updated on the server