On Tue, Jan 19, 2016 at 04:18:46PM +0000, Richard W.M. Jones wrote: > Libvirt has a fixed 15 second timeout for qemu to exit. If qemu is > writing to a slow USB key, it can hang (in D state) for much longer > than this - many minutes usually. > > The solution is to check specifically for the libvirt EBUSY error when > this happens, and retry the virDomainDestroyFlags operation > (indefinitely). > > See also the description here: > https://www.redhat.com/archives/libvir-list/2016-January/msg00767.html > > Similar to the following OpenStack Nova commit: > http://git.openstack.org/cgit/openstack/nova/commit/?id=3907867 > > Thanks: Kashyap Chamarthy and Daniel Berrange. > --- > src/launch-libvirt.c | 45 +++++++++++++++++++++++++++++++++++---------- > 1 file changed, 35 insertions(+), 10 deletions(-) > > diff --git a/src/launch-libvirt.c b/src/launch-libvirt.c > index 8215e02..90b6c49 100644 > --- a/src/launch-libvirt.c > +++ b/src/launch-libvirt.c > @@ -25,6 +25,7 @@ > #include <unistd.h> > #include <fcntl.h> > #include <grp.h> > +#include <errno.h> > #include <sys/types.h> > #include <sys/stat.h> > #include <assert.h> > @@ -2015,6 +2016,8 @@ ignore_errors (void *ignore, virErrorPtr ignore2) > /* empty */ > } > > +static int destroy_domain (guestfs_h *g, virDomainPtr dom, int check_for_errors); > + > static int > shutdown_libvirt (guestfs_h *g, void *datav, int check_for_errors) > { > @@ -2023,23 +2026,14 @@ shutdown_libvirt (guestfs_h *g, void *datav, int check_for_errors) > virDomainPtr dom = data->dom; > size_t i; > int ret = 0; > - int flags; > > /* Note that we can be called back very early in launch (specifically > * from launch_libvirt itself), when conn and dom might be NULL. > */ > - > if (dom != NULL) { > - flags = check_for_errors ? VIR_DOMAIN_DESTROY_GRACEFUL : 0; > - debug (g, "calling virDomainDestroy \"%s\" flags=%s", > - data->name, check_for_errors ? "VIR_DOMAIN_DESTROY_GRACEFUL" : "0"); > - if (virDomainDestroyFlags (dom, flags) == -1) { > - libvirt_error (g, _("could not destroy libvirt domain")); > - ret = -1; > - } > + ret = destroy_domain (g, dom, check_for_errors); > virDomainFree (dom); > } > - > if (conn != NULL) > virConnectClose (conn); > > @@ -2068,6 +2062,37 @@ shutdown_libvirt (guestfs_h *g, void *datav, int check_for_errors) > return ret; > } > > +/* Wrapper around virDomainDestroy which handles errors and retries.. */ > +static int > +destroy_domain (guestfs_h *g, virDomainPtr dom, int check_for_errors) > +{ > + const int flags = check_for_errors ? VIR_DOMAIN_DESTROY_GRACEFUL : 0; > + virErrorPtr err; > + > + again: > + debug (g, "calling virDomainDestroy flags=%s", > + check_for_errors ? "VIR_DOMAIN_DESTROY_GRACEFUL" : "0"); > + if (virDomainDestroyFlags (dom, flags) == -1) { > + err = virGetLastError (); > + > + /* Second chance if we're just waiting for qemu to shut down. See: > + * https://www.redhat.com/archives/libvir-list/2016-January/msg00767.html > + */ > + if ((flags & VIR_DOMAIN_DESTROY_GRACEFUL) && > + err && err->code == VIR_ERR_SYSTEM_ERROR && err->int1 == EBUSY) > + goto again; NB, you could get that error even if you don't specify VIR_DOMAIN_DESTROY_GRACEFUL, because even SIGKILL can fail to kill QEMU if it is in an uninterruptable sleep on a dead NFS server for example and hard,nointr is used as mount options. So perhaps you don't want to check flags here ?

> + > + /* "Domain not found" is not treated as an error. */ > + if (err && err->code == VIR_ERR_NO_DOMAIN) > + return 0; > + > + libvirt_error (g, _("could not destroy libvirt domain")); > + return -1; > + } > + > + return 0; > +} I don't know the use context from libguestfs POV, but is there any scenario in which a user would want a way to time out this, instead of making libguestfs wait forever ?