cifs: fix smb3_zero_range so it can expand the file-size when required

This allows fallocate -z to work against a Windows2016 share.

This is due to the SMB3 ZERO_RANGE command does not modify the filesize.
To address this we will now append a compounded SET-INFO to update the
end-of-file information.

This brings xfstests generic/469 closer to working against a windows share.

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/cifs/smb2pdu.h

@@ -959,6 +959,13 @@ struct duplicate_extents_to_file {
 	__le64 ByteCount;  /* Bytes to be copied */
 } __packed;
 
+/*
+ * Maximum number of iovs we need for an ioctl request.
+ * [0] : struct smb2_ioctl_req
+ * [1] : in_data
+ */
+#define SMB2_IOCTL_IOV_SIZE 2
+
 struct smb2_ioctl_req {
 	struct smb2_sync_hdr sync_hdr;
 	__le16 StructureSize;	/* Must be 57 */