tools: hv: use FIFREEZE/FITHAW in hv_vss_daemon

As suggested by Paolo Bonzini, use ioctl instead of calling fsfreeze.

Signed-off-by: Olaf Hering <olaf@aepfle.de>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 22 insertions, 9 deletions

diff --git a/tools/hv/hv_vss_daemon.c b/tools/hv/hv_vss_daemon.c
index a5da91df4f76..dc73a897d8c6 100644
--- a/tools/hv/hv_vss_daemon.c
+++ b/tools/hv/hv_vss_daemon.c
@@ -21,7 +21,9 @@
 #include <sys/types.h>
 #include <sys/socket.h>
 #include <sys/poll.h>
+#include <sys/ioctl.h>
 #include <linux/types.h>
+#include <fcntl.h>
 #include <stdio.h>
 #include <mntent.h>
 #include <stdlib.h>
@@ -30,6 +32,7 @@
 #include <ctype.h>
 #include <errno.h>
 #include <arpa/inet.h>
+#include <linux/fs.h>
 #include <linux/connector.h>
 #include <linux/hyperv.h>
 #include <linux/netlink.h>
@@ -44,21 +47,35 @@ static struct sockaddr_nl addr;
 #endif
 
 
+static int vss_do_freeze(char *dir, unsigned int cmd, char *fs_op)
+{
+        int ret, fd = open(dir, O_RDONLY);
+
+        if (fd < 0)
+                return 1;
+        ret = ioctl(fd, cmd, 0);
+        syslog(LOG_INFO, "VSS: %s of %s: %s\n", fs_op, dir, strerror(errno));
+        close(fd);
+        return !!ret;
+}
+
 static int vss_operate(int operation)
 {
         char *fs_op;
-        char cmd[512];
         char match[] = "/dev/";
         FILE *mounts;
         struct mntent *ent;
+        unsigned int cmd;
         int error = 0, root_seen = 0;
 
         switch (operation) {
         case VSS_OP_FREEZE:
-                fs_op = "-f ";
+                cmd = FIFREEZE;
+                fs_op = "freeze";
                 break;
         case VSS_OP_THAW:
-                fs_op = "-u ";
+                cmd = FITHAW;
+                fs_op = "thaw";
                 break;
         default:
                 return -1;
@@ -75,16 +92,12 @@ static int vss_operate(int operation)
                         root_seen = 1;
                         continue;
                 }
-                snprintf(cmd, sizeof(cmd), "fsfreeze %s '%s'", fs_op, ent->mnt_dir);
-                syslog(LOG_INFO, "VSS cmd is %s\n", cmd);
-                error |= system(cmd);
+                error |= vss_do_freeze(ent->mnt_dir, cmd, fs_op);
         }
         endmntent(mounts);
 
         if (root_seen) {
-                sprintf(cmd, "fsfreeze %s /", fs_op);
-                syslog(LOG_INFO, "VSS cmd is %s\n", cmd);
-                error |= system(cmd);
+                error |= vss_do_freeze("/", cmd, fs_op);
         }
 
         return error;