Re: [libvirt] [PATCH 3/3] libxl: provide integration with lock manager

21 Apr 2015

On Fri, Apr 17, 2015 at 03:36:22PM -0600, Jim Fehlig wrote:
...
Provide integration with libvirt's lock manager in the libxl driver.
Signed-off-by: Jim Fehlig <jfehlig@suse.com>
---
 src/Makefile.am                      | 12 +++++++++
 src/libxl/libvirtd_libxl.aug         |  2 ++
 src/libxl/libxl.conf                 | 10 ++++++++
 src/libxl/libxl_conf.c               | 14 +++++++++++
 src/libxl/libxl_conf.h               |  6 +++++
 src/libxl/libxl_domain.c             | 47 ++++++++++++++++++++++++++++++++++--
 src/libxl/libxl_domain.h             |  1 +
 src/libxl/libxl_driver.c             | 25 +++++++++++++++++++
 src/libxl/libxl_migration.c          |  6 +++++
 src/libxl/test_libvirtd_libxl.aug.in |  1 +
 10 files changed, 122 insertions(+), 2 deletions(-)

diff --git a/src/Makefile.am b/src/Makefile.am
index 9a5f16c..1438174 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -2246,6 +2246,12 @@ BUILT_SOURCES += locking/qemu-lockd.conf
 DISTCLEANFILES += locking/qemu-lockd.conf
 endif WITH_QEMU
+if WITH_LIBXL
+nodist_conf_DATA += locking/libxl-lockd.conf
+BUILT_SOURCES += locking/libxl-lockd.conf
+DISTCLEANFILES += locking/libxl-lockd.conf
+endif WITH_LIBXL
+
 locking/%-lockd.conf: $(srcdir)/locking/lockd.conf
  $(AM_V_GEN)$(MKDIR_P) locking ; \
  cp $< $@
@@ -2431,6 +2437,12 @@ nodist_conf_DATA += locking/qemu-sanlock.conf
 BUILT_SOURCES += locking/qemu-sanlock.conf
 DISTCLEANFILES += locking/qemu-sanlock.conf
 endif WITH_QEMU
+
+if WITH_LIBXL
+nodist_conf_DATA += locking/libxl-sanlock.conf
+BUILT_SOURCES += locking/libxl-sanlock.conf
+DISTCLEANFILES += locking/libxl-sanlock.conf
+endif WITH_LIBXL
 else ! WITH_SANLOCK
 EXTRA_DIST += $(LOCK_DRIVER_SANLOCK_SOURCES)
 endif ! WITH_SANLOCK
diff --git a/src/libxl/libvirtd_libxl.aug b/src/libxl/libvirtd_libxl.aug
index f225954..d5aa150 100644
--- a/src/libxl/libvirtd_libxl.aug
+++ b/src/libxl/libvirtd_libxl.aug
@@ -25,9 +25,11 @@ module Libvirtd_libxl =
(* Config entry grouped by function - same order as example config *)
    let autoballoon_entry = bool_entry "autoballoon"
+   let lock_entry = str_entry "lock_manager"
(* Each entry in the config is one of the following ... *)
    let entry = autoballoon_entry
+             | lock_entry
let comment = [ label "#comment" . del /#[ \t]*/ "# " .  store /([^ \t\n][^\n]*)?/ . del /\n/ "\n" ]
    let empty = [ label "#empty" . eol ]
diff --git a/src/libxl/libxl.conf b/src/libxl/libxl.conf
index c104d40..ba3de7a 100644
--- a/src/libxl/libxl.conf
+++ b/src/libxl/libxl.conf
@@ -10,3 +10,13 @@
 # autoballoon setting.
 #
 #autoballoon = 1
+
+
+# In order to prevent accidentally starting two domains that
+# share one writable disk, libvirt offers two approaches for
+# locking files: sanlock and virtlockd.  sanlock is an external
+# project which libvirt integrates with via the libvirt-lock-sanlock
+# package.  virtlockd is a libvirt implementation that is enabled with
+# "lockd".  Accepted values are "sanlock" and "lockd".
+#
+#lock_manager = "lockd"
diff --git a/src/libxl/libxl_conf.c b/src/libxl/libxl_conf.c
index 6ea2889..503e8a4 100644
--- a/src/libxl/libxl_conf.c
+++ b/src/libxl/libxl_conf.c
@@ -102,6 +102,7 @@ libxlDriverConfigDispose(void *obj)
     VIR_FREE(cfg->libDir);
     VIR_FREE(cfg->saveDir);
     VIR_FREE(cfg->autoDumpDir);
+    VIR_FREE(cfg->lockManagerName);
 }
@@ -1495,6 +1496,7 @@ int libxlDriverConfigLoadFile(libxlDriverConfigPtr cfg,
                               const char *filename)
 {
     virConfPtr conf = NULL;
+    virConfValuePtr p;
     int ret = -1;
/* Check the file is readable before opening it, otherwise
@@ -1512,6 +1514,18 @@ int libxlDriverConfigLoadFile(libxlDriverConfigPtr cfg,
     if (libxlGetAutoballoonConf(cfg, conf) < 0)
         goto cleanup;
+    if ((p = virConfGetValue(conf, "lock_manager"))) {
+        if (p->type != VIR_CONF_STRING) {
+            virReportError(VIR_ERR_INTERNAL_ERROR,
+                           "%s",
+                           _("Unexpected type for 'lock_manager' setting"));
+            goto cleanup;
+        }
+
+        if (VIR_STRDUP(cfg->lockManagerName, p->str) < 0)
+            goto cleanup;
+    }
+
     ret = 0;
cleanup:
diff --git a/src/libxl/libxl_conf.h b/src/libxl/libxl_conf.h
index 5ba1a71..0a1c0db 100644
--- a/src/libxl/libxl_conf.h
+++ b/src/libxl/libxl_conf.h
@@ -38,6 +38,7 @@
 # include "virobject.h"
 # include "virchrdev.h"
 # include "virhostdev.h"
+# include "locking/lock_manager.h"
# define LIBXL_DRIVER_NAME "xenlight"
 # define LIBXL_VNC_PORT_MIN  5900
@@ -98,6 +99,8 @@ struct _libxlDriverConfig {
      * memory for new domains from domain0. */
     bool autoballoon;
+    char *lockManagerName;
+
     /* Once created, caps are immutable */
     virCapsPtr caps;
@@ -144,6 +147,9 @@ struct _libxlDriverPrivate {
/* Immutable pointer, lockless APIs*/
     virSysinfoDefPtr hostsysinfo;
+
+    /* Immutable pointer. lockless access */
+    virLockManagerPluginPtr lockManager;
 };
# define LIBXL_SAVE_MAGIC "libvirt-xml\n \0 \r"
diff --git a/src/libxl/libxl_domain.c b/src/libxl/libxl_domain.c
index 77d46d0..70247f5 100644
--- a/src/libxl/libxl_domain.c
+++ b/src/libxl/libxl_domain.c
@@ -34,6 +34,7 @@
 #include "virlog.h"
 #include "virstring.h"
 #include "virtime.h"
+#include "locking/domain_lock.h"
#define VIR_FROM_THIS VIR_FROM_LIBXL
@@ -217,12 +218,36 @@ libxlDomainObjPrivateFree(void *data)
 {
     libxlDomainObjPrivatePtr priv = data;
+    VIR_FREE(priv->lockState);
     virObjectUnref(priv);
 }
+static int
+libxlDomainObjPrivateXMLParse(xmlXPathContextPtr ctxt, void *data)
+{
+    libxlDomainObjPrivatePtr priv = data;
+
+    priv->lockState = virXPathString("string(./lockstate)", ctxt);
+
+    return 0;
+}
+
+static int
+libxlDomainObjPrivateXMLFormat(virBufferPtr buf, void *data)
+{
+    libxlDomainObjPrivatePtr priv = data;
+
+    if (priv->lockState)
+        virBufferAsprintf(buf, "<lockstate>%s</lockstate>\n", priv->lockState);
+
+    return 0;
+}
+
 virDomainXMLPrivateDataCallbacks libxlDomainXMLPrivateDataCallbacks = {
     .alloc = libxlDomainObjPrivateAlloc,
     .free = libxlDomainObjPrivateFree,
+    .parse = libxlDomainObjPrivateXMLParse,
+    .format = libxlDomainObjPrivateXMLFormat,
 };
@@ -668,6 +693,11 @@ libxlDomainCleanup(libxlDriverPrivatePtr driver,
     virHostdevReAttachDomainDevices(hostdev_mgr, LIBXL_DRIVER_NAME,
                                     vm->def, VIR_HOSTDEV_SP_PCI, NULL);
+    VIR_FREE(priv->lockState);
+    if (virDomainLockProcessPause(driver->lockManager, vm, &priv->lockState) < 0)
+        VIR_WARN("Unable to release lease on %s", vm->def->name);
+    VIR_DEBUG("Preserving lock state '%s'", NULLSTR(priv->lockState));
I see a few calls to ProcessPause, but I'm not seeing any to ProcessResume,
so I think you might have missed a few places needing hooks.


Regards,
Daniel
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Re: [libvirt] [PATCH 3/3] libxl: provide integration with lock manager

Daniel P. Berrange