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[libvirt] [PATCH] init: raise default system aio limits
by Eric Blake 05 Oct '11

05 Oct '11

https://bugzilla.redhat.com/show_bug.cgi?id=740899 documents that if qemu uses aio=native for its disks, then it consumes 128 aio requests per disk. On a host with multiple guests, this can quickly run out of kernel aio requests with the default aio-max-nr of 65536. Kernel developers have confirmed that there is no up-front cost to raising this limit (a larger limit merely implies that more aio requests can be issued in parallel, which in turn will result in more kernel memory allocation if the system really does use that many requests). Since the system default limit prevents 256 disks, which is well within libvirt's current scalability, this patch installs a file to raise the limit and document it in case a system administrator has further cause to tune the limit. The install only works on platforms new enough to source /etc/sysctl.d/* alongside /etc/sysctl.conf (F14 and RHEL 6). * daemon/libvirtd.sysctl: New file. * daemon/Makefile.am (EXTRA_DIST): Ship it. (install-init, uninstall-init): Install it. * libvirt.spec.in (%files): Include it in rpm. --- So far, I've confirmed that this passes 'make distcheck' (well, once https://www.redhat.com/archives/libvir-list/2011-October/msg00074.html is applied) and 'make rpm', although I didn't actually try installing the resulting rpm nor rebooting a system to see if it takes effect. daemon/Makefile.am | 11 ++++++++--- daemon/libvirtd.sysctl | 8 ++++++++ libvirt.spec.in | 5 +++++ 3 files changed, 21 insertions(+), 3 deletions(-) create mode 100644 daemon/libvirtd.sysctl diff --git a/daemon/Makefile.am b/daemon/Makefile.am index 690bf85..1cf2b73 100644 --- a/daemon/Makefile.am +++ b/daemon/Makefile.am @@ -38,6 +38,7 @@ EXTRA_DIST = \ libvirtd.policy-1 \ libvirtd.sasl \ libvirtd.sysconf \ + libvirtd.sysctl \ libvirtd.aug \ libvirtd.logrotate.in \ libvirtd.qemu.logrotate.in \ @@ -252,16 +253,20 @@ install-logrotate: $(LOGROTATE_CONFS) if LIBVIRT_INIT_SCRIPT_RED_HAT install-init: libvirtd.init - mkdir -p $(DESTDIR)$(sysconfdir)/rc.d/init.d + mkdir -p $(DESTDIR)$(sysconfdir)/rc.d/init.d \ + $(DESTDIR)$(sysconfdir)/sysconfig \ + $(DESTDIR)$(sysconfdir)/sysctl.d $(INSTALL_SCRIPT) libvirtd.init \ $(DESTDIR)$(sysconfdir)/rc.d/init.d/libvirtd - mkdir -p $(DESTDIR)$(sysconfdir)/sysconfig $(INSTALL_DATA) $(srcdir)/libvirtd.sysconf \ $(DESTDIR)$(sysconfdir)/sysconfig/libvirtd + $(INSTALL_DATA) $(srcdir)/libvirtd.sysctl \ + $(DESTDIR)$(sysconfdir)/sysctl.d/libvirtd uninstall-init: rm -f $(DESTDIR)$(sysconfdir)/rc.d/init.d/libvirtd \ - $(DESTDIR)$(sysconfdir)/sysconfig/libvirtd + $(DESTDIR)$(sysconfdir)/sysconfig/libvirtd \ + $(DESTDIR)$(sysconfdir)/sysctl.d/libvirtd BUILT_SOURCES += libvirtd.init diff --git a/daemon/libvirtd.sysctl b/daemon/libvirtd.sysctl new file mode 100644 index 0000000..3c70884 --- /dev/null +++ b/daemon/libvirtd.sysctl @@ -0,0 +1,8 @@ +# The kernel allocates aio memory on demand, and this number limits the +# number of parallel aio requests; the only drawback of a larger limit is +# that a malicious guest could issue parallel requests to cause the kernel +# to set aside memory. Set this number at least as large as +# 128 * (number of virtual disks on the host) +# Libvirt uses a default of 1M requests to allow 8k disks, with at most +# 64M of kernel memory if all disks hit an aio request at the same time. +fs.aio-max-size = 1048576 diff --git a/libvirt.spec.in b/libvirt.spec.in index b87e3f6..9f5797a 100644 --- a/libvirt.spec.in +++ b/libvirt.spec.in @@ -962,6 +962,11 @@ fi %doc daemon/libvirtd.upstart %config(noreplace) %{_sysconfdir}/sysconfig/libvirtd %config(noreplace) %{_sysconfdir}/libvirt/libvirtd.conf +%if 0%{?fedora} >= 14 || 0%{?rhel} >= 6 +%config(noreplace) %{_sysconfdir}/sysctl.d/libvirtd +%else +rm -f $RPM_BUILD_ROOT%{_sysconfdir}/sysctl.d/libvirtd +%endif %if %{with_dtrace} %{_datadir}/systemtap/tapset/libvirtd.stp %endif -- 1.7.4.4

2 2

[libvirt] [PATCH] maint: fix minor issues in virterror public header
by Eric Blake 05 Oct '11

05 Oct '11

Consistent use of tabs, fewer long lines, and a typo fix. * include/libvirt/virterror.h: Fix typos, layout. --- Pushing under the trivial rule. include/libvirt/virterror.h | 19 ++++++++++--------- 1 files changed, 10 insertions(+), 9 deletions(-) diff --git a/include/libvirt/virterror.h b/include/libvirt/virterror.h index 0c98014..dfbe2bc 100644 --- a/include/libvirt/virterror.h +++ b/include/libvirt/virterror.h @@ -66,7 +66,8 @@ typedef enum { VIR_FROM_SECURITY = 24, /* Error from security framework */ VIR_FROM_VBOX = 25, /* Error from VirtualBox driver */ VIR_FROM_INTERFACE = 26, /* Error when operating on an interface */ - VIR_FROM_ONE = 27, /* The OpenNebula driver no longer exists. Retained for ABI/API compat only */ + VIR_FROM_ONE = 27, /* The OpenNebula driver no longer exists. + Retained for ABI/API compat only */ VIR_FROM_ESX = 28, /* Error from ESX driver */ VIR_FROM_PHYP = 29, /* Error from IBM power hypervisor */ VIR_FROM_SECRET = 30, /* Error from secret storage */ @@ -79,10 +80,10 @@ typedef enum { VIR_FROM_SYSINFO = 37, /* Error from sysinfo/SMBIOS */ VIR_FROM_STREAMS = 38, /* Error from I/O streams */ VIR_FROM_VMWARE = 39, /* Error from VMware driver */ - VIR_FROM_EVENT = 40, /* Error from event loop impl */ + VIR_FROM_EVENT = 40, /* Error from event loop impl */ VIR_FROM_LIBXL = 41, /* Error from libxenlight driver */ - VIR_FROM_LOCKING = 42, /* Error from lock manager */ - VIR_FROM_HYPERV = 43, /* Error from Hyper-V driver */ + VIR_FROM_LOCKING = 42, /* Error from lock manager */ + VIR_FROM_HYPERV = 43, /* Error from Hyper-V driver */ } virErrorDomain; @@ -232,12 +233,12 @@ typedef enum { VIR_ERR_HOOK_SCRIPT_FAILED = 70, /* a synchronous hook script failed */ VIR_ERR_INVALID_DOMAIN_SNAPSHOT = 71,/* invalid domain snapshot */ VIR_ERR_NO_DOMAIN_SNAPSHOT = 72, /* domain snapshot not found */ - VIR_ERR_INVALID_STREAM = 73, /* stream pointer not valid */ - VIR_ERR_ARGUMENT_UNSUPPORTED = 74, /* valid API use but unsupported by + VIR_ERR_INVALID_STREAM = 73, /* stream pointer not valid */ + VIR_ERR_ARGUMENT_UNSUPPORTED = 74, /* valid API use but unsupported by the given driver */ - VIR_ERR_STORAGE_PROBE_FAILED = 75, /* storage pool proble failed */ - VIR_ERR_STORAGE_POOL_BUILT = 76, /* storage pool already built */ - VIR_ERR_SNAPSHOT_REVERT_RISKY = 77, /* force was not requested for a + VIR_ERR_STORAGE_PROBE_FAILED = 75, /* storage pool probe failed */ + VIR_ERR_STORAGE_POOL_BUILT = 76, /* storage pool already built */ + VIR_ERR_SNAPSHOT_REVERT_RISKY = 77, /* force was not requested for a risky domain snapshot revert */ } virErrorNumber; -- 1.7.4.4

1 0

[libvirt] [RFC PATCHv2 0/9] DHCP snooping support for libvirt.
by David L Stevens 05 Oct '11

05 Oct '11

This series of patches adds DHCP snooping support to libvirt. This version saves leases on disk for restoration after a libvirtd restart and allows selection of different ip_learning methods by setting filter parameter "ip_learning" to one of "any" (existing IP learning code) "none" (static only addresses) or "DHCP" (DHCP Snooping). This code does not (yet) support passing lease information across a migration. A migrated guest requires a DHCP ACK (e.g., via ifdown/ifup on the guest) to send/receive traffic for DHCP-learned addresses after a migration. David L Stevens (9): support continue/return allow required ARP packets reverse sense of address matching make default chain policy "DROP" allow chain modification support addRules support variable value changing add DHCP snooping add leasefile support examples/xml/nwfilter/Makefile.am | 5 +- examples/xml/nwfilter/allow-arp.xml | 5 +- examples/xml/nwfilter/allow-arpip.xml | 3 + examples/xml/nwfilter/allow-arpmac.xml | 3 + examples/xml/nwfilter/clean-traffic.xml | 6 +- examples/xml/nwfilter/no-arp-spoofing.xml | 38 +- examples/xml/nwfilter/no-arpip-spoofing.xml | 10 + examples/xml/nwfilter/no-arpmac-spoofing.xml | 5 + examples/xml/nwfilter/no-ip-spoofing.xml | 9 +- examples/xml/nwfilter/no-mac-spoofing.xml | 10 +- examples/xml/nwfilter/no-other-l2-traffic.xml | 13 +- examples/xml/nwfilter/no-other-rarp-traffic.xml | 3 - examples/xml/nwfilter/qemu-announce-self.xml | 1 - src/Makefile.am | 2 + src/conf/nwfilter_conf.c | 12 +- src/conf/nwfilter_conf.h | 16 +- src/nwfilter/nwfilter_dhcpsnoop.c | 938 +++++++++++++++++++++++ src/nwfilter/nwfilter_dhcpsnoop.h | 36 + src/nwfilter/nwfilter_driver.c | 5 + src/nwfilter/nwfilter_ebiptables_driver.c | 225 +++++-- src/nwfilter/nwfilter_gentech_driver.c | 199 ++++- src/nwfilter/nwfilter_gentech_driver.h | 11 + 22 files changed, 1419 insertions(+), 136 deletions(-) create mode 100644 examples/xml/nwfilter/allow-arpip.xml create mode 100644 examples/xml/nwfilter/allow-arpmac.xml create mode 100644 examples/xml/nwfilter/no-arpip-spoofing.xml create mode 100644 examples/xml/nwfilter/no-arpmac-spoofing.xml delete mode 100644 examples/xml/nwfilter/no-other-rarp-traffic.xml create mode 100644 src/nwfilter/nwfilter_dhcpsnoop.c create mode 100644 src/nwfilter/nwfilter_dhcpsnoop.h -- 1.7.6.4

3 15

[libvirt] [PATCH 0/2] snapshot: add force for risky reverts
by Eric Blake 05 Oct '11

05 Oct '11

I first documented the need for force back in my RFC: https://www.redhat.com/archives/libvir-list/2011-August/msg00361.html but only now got around to implementing it. At the moment, I'm posting the code for early review. I'm still in the process of testing out multiple scenarios, and will send followup mail detailing the actual steps I took using virsh to cover the multiple scenarios. Eric Blake (2): snapshot: add REVERT_FORCE to API snapshot: enforce REVERT_FORCE on qemu include/libvirt/libvirt.h.in | 1 + include/libvirt/virterror.h | 2 + src/libvirt.c | 22 +++++++++++++++++++ src/qemu/qemu_driver.c | 47 +++++++++++++++++++++++++++++++++--------- src/util/virterror.c | 6 +++++ tools/virsh.c | 19 ++++++++++++++++- tools/virsh.pod | 17 +++++++++++++++ 7 files changed, 103 insertions(+), 11 deletions(-) -- 1.7.4.4

2 11

[libvirt] [PATCH] qemu: Don't fail virDomainGetInfo if we can't update balloon info
by Jiri Denemark 05 Oct '11

05 Oct '11

Qemu driver tries to update balloon data in virDomainGetInfo and if it can't do so because there is another monitor job running, it just reports what's known in domain def. However, if there was no job running but getting the data from qemu fails, we would fail the whole API. This doesn't make sense. Let's make the failure nonfatal. --- src/qemu/qemu_driver.c | 13 +++++++++---- 1 files changed, 9 insertions(+), 4 deletions(-) diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c index dc34e1d..276dc06 100644 --- a/src/qemu/qemu_driver.c +++ b/src/qemu/qemu_driver.c @@ -2071,37 +2071,42 @@ static int qemudDomainGetInfo(virDomainPtr dom, } else if (qemuDomainJobAllowed(priv, QEMU_JOB_QUERY)) { if (qemuDomainObjBeginJob(driver, vm, QEMU_JOB_QUERY) < 0) goto cleanup; if (!virDomainObjIsActive(vm)) err = 0; else { qemuDomainObjEnterMonitor(driver, vm); err = qemuMonitorGetBalloonInfo(priv->mon, &balloon); qemuDomainObjExitMonitor(driver, vm); } if (qemuDomainObjEndJob(driver, vm) == 0) { vm = NULL; goto cleanup; } - if (err < 0) - goto cleanup; - if (err == 0) + if (err < 0) { + /* We couldn't get current memory allocation but that's not + * a show stopper; we wouldn't get it if there was a job + * active either + */ + info->memory = vm->def->mem.cur_balloon; + } else if (err == 0) { /* Balloon not supported, so maxmem is always the allocation */ info->memory = vm->def->mem.max_balloon; - else + } else { info->memory = balloon; + } } else { info->memory = vm->def->mem.cur_balloon; } } else { info->memory = vm->def->mem.cur_balloon; } info->nrVirtCpu = vm->def->vcpus; ret = 0; cleanup: if (vm) virDomainObjUnlock(vm); return ret; } -- 1.7.7

2 2

[libvirt] [RFC] security_dac: don't chown iso file
by Serge E. Hallyn 05 Oct '11

05 Oct '11

isos are read-only, so libvirt doesn't need to chown them. In one of our testing setups, libvirt uses mirrorred isos. Since libvirt chowns the files, (and especially does not chown them back) the mirror refuses to update the iso. This patch prevents libvirt from chowning files. Does this seem reasonable? Signed-off-by: Serge Hallyn <serge.hallyn(a)canonical.com> --- src/security/security_dac.c | 2 ++ 1 files changed, 2 insertions(+), 0 deletions(-) diff --git a/src/security/security_dac.c b/src/security/security_dac.c index af02236..e7db324 100644 --- a/src/security/security_dac.c +++ b/src/security/security_dac.c @@ -555,6 +555,8 @@ virSecurityDACSetSecurityAllLabel(virSecurityManagerPtr mgr, /* XXX fixme - we need to recursively label the entire tree :-( */ if (vm->def->disks[i]->type == VIR_DOMAIN_DISK_TYPE_DIR) continue; + if (vm->def->disks[i]->device == VIR_DOMAIN_DISK_DEVICE_CDROM) + continue; if (virSecurityDACSetSecurityImageLabel(mgr, vm, vm->def->disks[i]) < 0) -- 1.7.5.4

4 5

[libvirt] [PATCH] qemu: Fix migration with dname
by Jiri Denemark 05 Oct '11

05 Oct '11

Destination libvirtd remembers the original name in the prepare phase and clears it in the finish phase. The original name is used when comparing domain name in migration cookie. --- Notes: Originally, I wanted to transfer the new name in migration cookie but that appeared to be much more complicated and it would require adding new Confirm API since the current version does not have 'dname' parameter. src/qemu/qemu_domain.c | 1 + src/qemu/qemu_domain.h | 1 + src/qemu/qemu_migration.c | 19 ++++++++++++++++--- 3 files changed, 18 insertions(+), 3 deletions(-) diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c index d3ad192..65f721a 100644 --- a/src/qemu/qemu_domain.c +++ b/src/qemu/qemu_domain.c @@ -231,6 +231,7 @@ static void qemuDomainObjPrivateFree(void *data) qemuDomainObjFreeJob(priv); VIR_FREE(priv->vcpupids); VIR_FREE(priv->lockState); + VIR_FREE(priv->origname); /* This should never be non-NULL if we get here, but just in case... */ if (priv->mon) { diff --git a/src/qemu/qemu_domain.h b/src/qemu/qemu_domain.h index cdf1375..d9f323c 100644 --- a/src/qemu/qemu_domain.h +++ b/src/qemu/qemu_domain.h @@ -126,6 +126,7 @@ struct _qemuDomainObjPrivate { int jobs_queued; unsigned long migMaxBandwidth; + char *origname; }; struct qemuDomainWatchdogEvent diff --git a/src/qemu/qemu_migration.c b/src/qemu/qemu_migration.c index 1122dab..4516231 100644 --- a/src/qemu/qemu_migration.c +++ b/src/qemu/qemu_migration.c @@ -254,12 +254,18 @@ error: static qemuMigrationCookiePtr qemuMigrationCookieNew(virDomainObjPtr dom) { + qemuDomainObjPrivatePtr priv = dom->privateData; qemuMigrationCookiePtr mig = NULL; + const char *name; if (VIR_ALLOC(mig) < 0) goto no_memory; - if (!(mig->name = strdup(dom->def->name))) + if (priv->origname) + name = priv->origname; + else + name = dom->def->name; + if (!(mig->name = strdup(name))) goto no_memory; memcpy(mig->uuid, dom->def->uuid, VIR_UUID_BUFLEN); @@ -1064,6 +1070,7 @@ qemuMigrationPrepareAny(struct qemud_driver *driver, unsigned long long now; qemuMigrationCookiePtr mig = NULL; bool tunnel = !!st; + char *origname = NULL; if (virTimeMs(&now) < 0) return -1; @@ -1078,7 +1085,7 @@ qemuMigrationPrepareAny(struct qemud_driver *driver, /* Target domain name, maybe renamed. */ if (dname) { - VIR_FREE(def->name); + origname = def->name; def->name = strdup(dname); if (def->name == NULL) goto cleanup; @@ -1095,6 +1102,8 @@ qemuMigrationPrepareAny(struct qemud_driver *driver, } def = NULL; priv = vm->privateData; + priv->origname = origname; + origname = NULL; if (!(mig = qemuMigrationEatCookie(driver, vm, cookiein, cookieinlen, QEMU_MIGRATION_COOKIE_LOCKSTATE))) @@ -1175,6 +1184,7 @@ qemuMigrationPrepareAny(struct qemud_driver *driver, ret = 0; cleanup: + VIR_FREE(origname); virDomainDefFree(def); VIR_FORCE_CLOSE(dataFD[0]); VIR_FORCE_CLOSE(dataFD[1]); @@ -2542,6 +2552,7 @@ qemuMigrationFinish(struct qemud_driver *driver, qemuMigrationCookiePtr mig = NULL; virErrorPtr orig_err = NULL; int cookie_flags = 0; + qemuDomainObjPrivatePtr priv = vm->privateData; VIR_DEBUG("driver=%p, dconn=%p, vm=%p, cookiein=%s, cookieinlen=%d, " "cookieout=%p, cookieoutlen=%p, flags=%lx, retcode=%d", @@ -2695,8 +2706,10 @@ endjob: } cleanup: - if (vm) + if (vm) { + VIR_FREE(priv->origname); virDomainObjUnlock(vm); + } if (event) qemuDomainEventQueue(driver, event); qemuMigrationCookieFree(mig); -- 1.7.7

3 6

[libvirt] "Connection does not support host device enumeration"
by Kaushal Shriyan 05 Oct '11

05 Oct '11

Hi, I have "20:04.0 Network controller: Sangoma Technologies Corp. A104d QUAD T1/E1 AFT card" on Host OS, Its not visible on guest OS using linux KVM application. I did open the window for guest from virt-manager on my Ubuntu Linux Desktop 11.04, shut down the guest, then select the "Details" view from the menu on that window, and click "Add Hardware" at the bottom, select "PCI Host Device" in the selections on the left, and find your device in the list of host devices on the right. Then click "Finish". Finally, start your guest up again, and the device should appear. I get "Connection does not support host device enumeration" Any clue ? libvirt-0.8.2-22.el5 version running on CentOS Linux Server version 5.6 Please let me know if you need any additional information Regards, Kaushal

3 10

[libvirt] [RFC PATCH] snapshot: better virsh handling of missing current, parent
by Eric Blake 04 Oct '11

04 Oct '11

Previously, virsh 'snapshot-parent' and 'snapshot-current' were completely silent in the case where the code conclusively proved there was no parent or current snapshot, but differed in exit status; this silence caused some confusion on whether the commands worked. Furthermore, commit d1be48f introduced a regression where snapshot-parent would leak output about an unknown function, but only on the first attempt, when talking to an older server that lacks virDomainSnapshotGetParent. This changes things to consistenly report an error message and exit with status 1 when no snapshot exists, and to avoid leaking unknown function warnings when using fallbacks. * tools/virsh.c (vshGetSnapshotParent): Alter signature, to distinguish between real error and missing parent. Don't pollute last_error on success. (cmdSnapshotParent): Adjust caller. Always output message on failure. (vshGetSnapshotParent): Adjust caller. (cmdSnapshotCurrent): Always output message on failure. --- This patch is an RFC because of backwards-compatibility concerns: Currently, snapshot-current outputs nothing but has status 0 if there is no current snapshot; but snapshot-parent outputs nothing but has status 1 if there is no parent snapshot. Either way, we have an inconsistency that needs to be fixed, and gaining consistency means breaking backwards compatibility with at least one command. Approach 1 (this patch): change snapshot-parent and snapshot-current to always output something, whether to stdout on success or to stderr on failure, with lack of a snapshot being considered a failure (where snapshot-current used to treat it as success). Approach 2 (not written) since snapshot-current existed much longer, makesnapshot-parent consistent by giving status 0 when it is silent. Preferences? (I guess mine is approach 1, by evidence of this patch). tools/virsh.c | 54 +++++++++++++++++++++++++++++++++++++++--------------- 1 files changed, 39 insertions(+), 15 deletions(-) diff --git a/tools/virsh.c b/tools/virsh.c index 1909dce..179cda5 100644 --- a/tools/virsh.c +++ b/tools/virsh.c @@ -12945,6 +12945,7 @@ cmdSnapshotCurrent(vshControl *ctl, const vshCmd *cmd) char *xml = NULL; const char *snapshotname = NULL; unsigned int flags = 0; + const char *domname; if (vshCommandOptBool(cmd, "security-info")) flags |= VIR_DOMAIN_XML_SECURE; @@ -12952,7 +12953,7 @@ cmdSnapshotCurrent(vshControl *ctl, const vshCmd *cmd) if (!vshConnectionUsability(ctl, ctl->conn)) goto cleanup; - dom = vshCommandOptDomain(ctl, cmd, NULL); + dom = vshCommandOptDomain(ctl, cmd, &domname); if (dom == NULL) goto cleanup; @@ -12986,9 +12987,12 @@ cmdSnapshotCurrent(vshControl *ctl, const vshCmd *cmd) } current = virDomainHasCurrentSnapshot(dom, 0); - if (current < 0) + if (current < 0) { + goto cleanup; + } else if (!current) { + vshError(ctl, _("domain '%s' has no current snapshot"), domname); goto cleanup; - else if (current) { + } else { const char *name = NULL; if (!(snapshot = virDomainSnapshotCurrent(dom, 0))) @@ -13010,6 +13014,8 @@ cmdSnapshotCurrent(vshControl *ctl, const vshCmd *cmd) ret = true; cleanup: + if (!ret) + virshReportError(ctl); VIR_FREE(xml); if (snapshot) virDomainSnapshotFree(snapshot); @@ -13020,26 +13026,33 @@ cleanup: } /* Helper function to get the name of a snapshot's parent. Caller - * must free the result. */ -static char * -vshGetSnapshotParent(vshControl *ctl, virDomainSnapshotPtr snapshot) + * must free the result. Returns 0 on success (including when it was + * proven no parent exists), and -1 on failure with error reported + * (such as no snapshot support or domain deleted in meantime). */ +static int +vshGetSnapshotParent(vshControl *ctl, virDomainSnapshotPtr snapshot, + char **parent_name) { virDomainSnapshotPtr parent = NULL; char *xml = NULL; xmlDocPtr xmldoc = NULL; xmlXPathContextPtr ctxt = NULL; - char *parent_name = NULL; + int ret = -1; + + *parent_name = NULL; /* Try new API, since it is faster. */ if (!ctl->useSnapshotGetXML) { parent = virDomainSnapshotGetParent(snapshot, 0); if (parent) { - /* API works, and virDomainSnapshotGetName will succeed */ - parent_name = vshStrdup(ctl, virDomainSnapshotGetName(parent)); + /* API works, and virDomainSnapshotGetName will be accurate */ + *parent_name = vshStrdup(ctl, virDomainSnapshotGetName(parent)); + ret = 0; goto cleanup; } if (last_error->code == VIR_ERR_NO_DOMAIN_SNAPSHOT) { /* API works, and we found a root with no parent */ + ret = 0; goto cleanup; } /* API didn't work, fall back to XML scraping. */ @@ -13054,15 +13067,23 @@ vshGetSnapshotParent(vshControl *ctl, virDomainSnapshotPtr snapshot) if (!xmldoc) goto cleanup; - parent_name = virXPathString("string(/domainsnapshot/parent/name)", ctxt); + *parent_name = virXPathString("string(/domainsnapshot/parent/name)", ctxt); + ret = 0; cleanup: + if (ret < 0) { + virshReportError(ctl); + vshError(ctl, "%s", _("unable to determine if snapshot has parent")); + } else { + virFreeError(last_error); + last_error = NULL; + } if (parent) virDomainSnapshotFree(parent); xmlXPathFreeContext(ctxt); xmlFreeDoc(xmldoc); VIR_FREE(xml); - return parent_name; + return ret; } /* @@ -13187,13 +13208,13 @@ cmdSnapshotList(vshControl *ctl, const vshCmd *cmd) if (snapshot) virDomainSnapshotFree(snapshot); snapshot = virDomainSnapshotLookupByName(dom, names[i], 0); - if (!snapshot) { + if (!snapshot || + vshGetSnapshotParent(ctl, snapshot, &parents[i]) < 0) { while (--i >= 0) VIR_FREE(parents[i]); VIR_FREE(parents); goto cleanup; } - parents[i] = vshGetSnapshotParent(ctl, snapshot); } for (i = 0 ; i < actual ; i++) { memset(indentBuf, '\0', sizeof indentBuf); @@ -13389,9 +13410,12 @@ cmdSnapshotParent(vshControl *ctl, const vshCmd *cmd) if (snapshot == NULL) goto cleanup; - parent = vshGetSnapshotParent(ctl, snapshot); - if (!parent) + if (vshGetSnapshotParent(ctl, snapshot, &parent) < 0) goto cleanup; + if (!parent) { + vshError(ctl, _("snapshot '%s' has no parent"), name); + goto cleanup; + } vshPrint(ctl, "%s", parent); -- 1.7.4.4

2 2

[libvirt] Deadlock when using custom handlers
by Guido Günther 04 Oct '11

04 Oct '11

Hi, virt-viewer is using it's own virEventRegisterImpl. With current libvirt this can deadlock when connection to nonexistant URIs like qemu+ssh:///unknownhost.example.com/system like: 23:47:00.338: 1526: debug : doRemoteOpen:503 : proceeding with name = qemu:///system 23:47:00.338: 1526: debug : doRemoteOpen:513 : Connecting with transport 2 23:47:00.338: 1526: debug : virCommandRunAsync:2042 : About to run LC_ALL=C LD_LIBRARY_PATH=/var/scratch/debian/libvirt/upstream/libvirt/src/.libs/ PATH=/usr/local/bin:/usr/bin:/bin:/usr/games:/home/agx/bin:/sbin:/usr/sbin:/usr/lib/git-core HOME=/home/agx USER=agx LOGNAME=agx SSH_AUTH_SOCK=/tmp/keyring-RNvlnT/ssh DISPLAY=:0 ssh pustekiste nc -U /var/run/libvirt/libvirt-sock-ro 23:47:00.339: 1526: debug : virCommandRunAsync:2058 : Command result 0, with PID 1527 23:47:00.339: 1526: debug : virNetSocketNew:115 : localAddr=(nil) remoteAddr=(nil) fd=6 errfd=8 pid=1527 23:47:00.339: 1526: debug : virNetSocketNew:173 : sock=0x8926d20 localAddrStr=(null) remoteAddrStr=(null) ** (virt-viewer:1526): DEBUG: Add handle 6 1 0x8926d20 23:47:00.339: 1526: debug : virNetClientNew:160 : client=0xb5b5f008 refs=2 23:47:00.339: 1526: debug : doRemoteOpen:640 : Trying authentication 23:47:00.339: 1526: debug : virNetMessageNew:44 : msg=0xb5b1e008 23:47:00.340: 1526: debug : virNetMessageEncodePayload:255 : Encode length as 28 23:47:00.340: 1526: debug : virNetClientIO:1035 : program=536903814 version=1 serial=0 proc=66 type=0 length=28 dispatch=(nil) 23:47:00.340: 1526: debug : virNetClientIO:1103 : We have the buck 0x8939940 0x8939940 23:47:00.350: 1526: debug : virNetClientIOEventLoop:979 : Giving up the buck due to I/O error 0x8939940 (nil) 23:47:00.350: 1526: debug : virNetClientIO:1130 : All done with our call (nil) 0x8939940 -1 23:47:00.350: 1526: debug : virNetMessageFree:57 : msg=0xb5b1e008 ** (virt-viewer:1526): DEBUG: Remove handle 1 6 <deadlock> Gdb displays the deadlock nicely: #0 0xb7710424 in __kernel_vsyscall () #1 0xb692cf02 in __lll_lock_wait () at ../nptl/sysdeps/unix/sysv/linux/i386/i686/../i486/lowlevellock.S:142 #2 0xb692839b in _L_lock_728 () from /lib/i386-linux-gnu/i686/cmov/libpthread.so.0 #3 0xb69281c1 in __pthread_mutex_lock (mutex=0x95e1c30) at pthread_mutex_lock.c:61 #4 0xb698fd07 in virMutexLock (m=0x95e1c30) at util/threads-pthread.c:85 #5 0xb6a5dd56 in virNetSocketEventFree (opaque=0x95e1c30) at rpc/virnetsocket.c:1147 #6 0x080514a1 in virt_viewer_events_remove_handle (watch=1) at virt-viewer-events.c:178 #7 0xb697264e in virEventRemoveHandle (watch=1) at util/event.c:84 #8 0xb6a608ed in virNetSocketRemoveIOCallback (sock=0x95e1c30) at rpc/virnetsocket.c:1221 #9 0xb6a57114 in virNetClientClose (client=0xb5b7e008) at rpc/virnetclient.c:280 #10 0xb6a46fc4 in doRemoteOpen (conn=0x95e1aa8, priv=0x95b1370, auth=0xbfc3b178, flags=1) at remote/remote_driver.c:705 #11 0xb6a49612 in remoteOpen (conn=0x95e1aa8, auth=0xbfc3b178, flags=1) at remote/remote_driver.c:820 #12 0xb69f70c6 in do_open (name=0x95aac10 "qemu+ssh://pustekiste:2222/system", auth=0xbfc3b178, flags=1) at libvirt.c:1054 #13 0xb69f9b88 in virConnectOpenAuth (name=0x95aac10 "qemu+ssh://pustekiste:2222/system", auth=0xbfc3b178, flags=1) at libvirt.c:1280 #14 0x080500cf in virt_viewer_start (app=0x95a1010) at virt-viewer.c:483 #15 0x08053be8 in virt_viewer_app_start (self=0x95a1010) at virt-viewer-app.c:1044 #16 0x0804f54d in main (argc=1, argv=0xbfc3b3f4) at virt-viewer-main.c:120 which is the sock->lock: virNetSocketRemoveIOCallback holds sock->lock -> virEventRemoveHandle -> impl_remove_handle -> opaque->ff -> virNetSocketEventFree want to hold sock->lock Working around this by removing the locks from virNetSocketRemoveIOCallback leads to another deadlock: #0 0xb77de424 in __kernel_vsyscall () #1 0xb69faf02 in __lll_lock_wait () at ../nptl/sysdeps/unix/sysv/linux/i386/i686/../i486/lowlevellock.S:142 #2 0xb69f639b in _L_lock_728 () from /lib/i386-linux-gnu/i686/cmov/libpthread.so.0 #3 0xb69f61c1 in __pthread_mutex_lock (mutex=0xb5c4c00c) at pthread_mutex_lock.c:61 #4 0xb6a5dd07 in virMutexLock (m=0xb5c4c00c) at util/threads-pthread.c:85 #5 0xb6b24a98 in virNetClientLock (client=0xb5c4c008) at rpc/virnetclient.c:99 #6 virNetClientFree (client=0xb5c4c008) at rpc/virnetclient.c:243 #7 0xb6b250b7 in virNetClientEventFree (opaque=0xb5c4c008) at rpc/virnetclient.c:117 #8 0xb6b2bd82 in virNetSocketEventFree (opaque=0x8aabc30) at rpc/virnetsocket.c:1156 #9 0x080514a1 in virt_viewer_events_remove_handle (watch=1) at virt-viewer-events.c:178 #10 0xb6a4064e in virEventRemoveHandle (watch=1) at util/event.c:84 #11 0xb6b2e8e5 in virNetSocketRemoveIOCallback (sock=0x8aabc30) at rpc/virnetsocket.c:1219 #12 0xb6b25114 in virNetClientClose (client=0xb5c4c008) at rpc/virnetclient.c:280 #13 0xb6b14fc4 in doRemoteOpen (conn=0x8aabaa8, priv=0x8a7b370, auth=0xbfbf1798, flags=1) at remote/remote_driver.c:705 #14 0xb6b17612 in remoteOpen (conn=0x8aabaa8, auth=0xbfbf1798, flags=1) at remote/remote_driver.c:820 #15 0xb6ac50c6 in do_open (name=0x8a74c10 "qemu+ssh://pustekiste:2222/system", auth=0xbfbf1798, flags=1) at libvirt.c:1054 #16 0xb6ac7b88 in virConnectOpenAuth (name=0x8a74c10 "qemu+ssh://pustekiste:2222/system", auth=0xbfbf1798, flags=1) at libvirt.c:1280 #17 0x080500cf in virt_viewer_start (app=0x8a6b010) at virt-viewer.c:483 #18 0x08053be8 in virt_viewer_app_start (self=0x8a6b010) at virt-viewer-app.c:1044 #19 0x0804f54d in main (argc=1, argv=0xbfbf1a14) at virt-viewer-main.c:120 which is the virNetClient lock: virNetClientClose holds client->lock -> virNetSocketRemoveIOCallback -> virEventRemoveHandle -> impl_remove_handle -> virNetSocketEventFree -> virNetClientEventFree wants the lock I didn't see a simple way to fix this but would welcome any suggestions. Cheers, -- Guido

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