Re: [libvirt] [PATCH] cmdMigrate: move vshConnect before vshWatchJob

>> On 8/8/2014 at 04:44 PM, in message

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(a)suse.com&gt; --- tools/virsh-domain.c | 26 ++++++++++++++++++++------ tools/virsh.h | 1 + 2 files changed, 21 insertions(+), 6 deletions(-) diff --git a/tools/virsh-domain.c b/tools/virsh-domain.c index f7193cb..2562326 100644 --- 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 7656407..b4df24b 100644 --- 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 */