Tools: hv: Handle the case when the target file exists correctly

Return the appropriate error code and handle the case when the target
file exists correctly. This fixes a bug.
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Cc: <stable@vger.kernel.org> [3.14]
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

include/uapi/linux/hyperv.h

@@ -305,6 +305,7 @@ enum hv_kvp_exchg_pool {
 #define HV_ERROR_DEVICE_NOT_CONNECTED	0x8007048F
 #define HV_INVALIDARG			0x80070057
 #define HV_GUID_NOTFOUND		0x80041002
+#define HV_ERROR_ALREADY_EXISTS		0x80070050
 
 #define ADDR_FAMILY_NONE	0x00
 #define ADDR_FAMILY_IPV4	0x01

tools/hv/hv_fcopy_daemon.c

@@ -82,8 +82,10 @@ static int hv_start_fcopy(struct hv_start_fcopy *smsg)
 
 	if (!access(target_fname, F_OK)) {
 		syslog(LOG_INFO, "File: %s exists", target_fname);
-		if (!smsg->copy_flags & OVER_WRITE)
+		if (!(smsg->copy_flags & OVER_WRITE)) {
+			error = HV_ERROR_ALREADY_EXISTS;
 			goto done;
+		}
 	}
 
 	target_fd = open(target_fname, O_RDWR | O_CREAT | O_CLOEXEC, 0744);