cmdMigrate: move vshConnect before vshWatchJob

A possible fix to issue:
http://www.redhat.com/archives/libvir-list/2014-August/thread.html#00227

While doing migration on KVM host, found problem sometimes:
VM is already running on the target host and disappears from source
host, but 'virsh migrate' command line hangs, cannot exit normally.
If pressing "ENTER" key, it will exit.

The code hangs at tools/virsh-domain.c: cmdMigrate
->vshWatchJob->poll():
poll() is trying to select pipe_fd, which is used to receive message
from doMigrate thread. In debugging, found that doMigrate finishes
and at the end it does call safewrite() to write the retval ('0' or
'1') to pipe_fd, and the write is completed. But cmdMigrate poll()
cannot get the event. If pressing "ENTER" key, poll() can get the
event and select pipe_fd, then command line can exit.

In current code, authentication thread which is called by vshConnect
will use stdin, and at the same time, in cmdMigrate main process,
poll() is listening to stdin, that probably affect poll() to get
pipe_fd event. Better to move authentication before vshWatchJob. With
this change, above problem does not exist.

Signed-off-by: Chunyan Liu <cyliu@suse.com>

diff --git a/tools/virsh-domain.c b/tools/virsh-domain.c
index f7193cb560e019466fd9464312db9eac7ed871c5..2562326d2aef318ad057ff1ef5b3c0e2e1f5e2d8 100644 (file)
--- a/tools/virsh-domain.c
+++ b/tools/virsh-domain.c
@@ -8965,6 +8965,7 @@ doMigrate(void *opaque)
     virTypedParameterPtr params = NULL;
     int nparams = 0;
     int maxparams = 0;
+    virConnectPtr dconn = data->dconn;
 
     sigemptyset(&sigmask);
     sigaddset(&sigmask, SIGINT);
@@ -9079,18 +9080,12 @@ doMigrate(void *opaque)
             ret = '0';
     } else {
         /* For traditional live migration, connect to the destination host directly. */
-        virConnectPtr dconn = NULL;
         virDomainPtr ddom = NULL;
 
-        dconn = vshConnect(ctl, desturi, false);
-        if (!dconn)
-            goto out;
-
         if ((ddom = virDomainMigrate3(dom, dconn, params, nparams, flags))) {
             virDomainFree(ddom);
             ret = '0';
         }
-        virConnectClose(dconn);
     }
 
  out:
@@ -9152,6 +9147,23 @@ cmdMigrate(vshControl *ctl, const vshCmd *cmd)
     data.cmd = cmd;
     data.writefd = p[1];
 
+    if (vshCommandOptBool(cmd, "p2p") || vshCommandOptBool(cmd, "direct")) {
+        data.dconn = NULL;
+    } else {
+        /* For traditional live migration, connect to the destination host. */
+        virConnectPtr dconn = NULL;
+        const char *desturi = NULL;
+
+        if (vshCommandOptStringReq(ctl, cmd, "desturi", &desturi) < 0)
+            goto cleanup;
+
+        dconn = vshConnect(ctl, desturi, false);
+        if (!dconn)
+            goto cleanup;
+
+        data.dconn = dconn;
+    }
+
     if (virThreadCreate(&workerThread,
                         true,
                         doMigrate,
@@ -9163,6 +9175,8 @@ cmdMigrate(vshControl *ctl, const vshCmd *cmd)
     virThreadJoin(&workerThread);
 
  cleanup:
+    if (data.dconn)
+        virConnectClose(data.dconn);
     virDomainFree(dom);
     VIR_FORCE_CLOSE(p[0]);
     VIR_FORCE_CLOSE(p[1]);

diff --git a/tools/virsh.h b/tools/virsh.h
index 7656407c9be532c1fb5c6b36fb4f2b2192676006..b4df24bb39d45b5fa26eb5ef79d3af7d61a71e45 100644 (file)
--- a/tools/virsh.h
+++ b/tools/virsh.h
@@ -371,6 +371,7 @@ struct _vshCtrlData {
     vshControl *ctl;
     const vshCmd *cmd;
     int writefd;
+    virConnectPtr dconn;
 };
 
 /* error handling */