libxl: provide integration with lock manager

Provide integration with libvirt's lock manager in the libxl driver.

Signed-off-by: Jim Fehlig <jfehlig@suse.com>

src/Makefile.am

@@ -2247,6 +2247,12 @@ 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 $< $@
@@ -2432,6 +2438,12 @@ 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

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 ]

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"

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);
 }
 
 
@@ -1498,6 +1499,7 @@ int libxlDriverConfigLoadFile(libxlDriverConfigPtr cfg,
                               const char *filename)
 {
     virConfPtr conf = NULL;
+    virConfValuePtr p;
     int ret = -1;
 
     /* Check the file is readable before opening it, otherwise
@@ -1515,6 +1517,18 @@ 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:

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"

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,
 };
 
 
@@ -667,6 +692,11 @@ 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));
+
     vm->def->id = -1;
 
     if (priv->deathW) {
@@ -960,6 +990,20 @@ libxlDomainStart(libxlDriverPrivatePtr driver, virDomainObjPtr vm,
                                        vm->def, VIR_HOSTDEV_SP_PCI) < 0)
         goto cleanup;
 
+    if (virDomainLockProcessStart(driver->lockManager,
+                                  "xen:///system",
+                                  vm,
+                                  true,
+                                  NULL) < 0)
+        goto cleanup;
+
+    if (virDomainLockProcessResume(driver->lockManager,
+                                  "xen:///system",
+                                  vm,
+                                  priv->lockState) < 0)
+        goto cleanup;
+    VIR_FREE(priv->lockState);
+
     /* Unlock virDomainObj while creating the domain */
     virObjectUnlock(vm);
 
@@ -990,7 +1034,7 @@ libxlDomainStart(libxlDriverPrivatePtr driver, virDomainObjPtr vm,
             virReportError(VIR_ERR_INTERNAL_ERROR,
                            _("libxenlight failed to restore domain '%s'"),
                            d_config.c_info.name);
-        goto cleanup;
+        goto release_dom;
     }
 
     /*
@@ -1003,6 +1047,7 @@ libxlDomainStart(libxlDriverPrivatePtr driver, virDomainObjPtr vm,
     if (libxl_evenable_domain_death(cfg->ctx, vm->def->id, 0, &priv->deathW))
         goto cleanup_dom;
 
+
     if ((dom_xml = virDomainDefFormat(vm->def, 0)) == NULL)
         goto cleanup_dom;
 
@@ -1040,6 +1085,7 @@ libxlDomainStart(libxlDriverPrivatePtr driver, virDomainObjPtr vm,
     goto cleanup;
 
  cleanup_dom:
+    ret = -1;
     if (priv->deathW) {
         libxl_evdisable_domain_death(cfg->ctx, priv->deathW);
         priv->deathW = NULL;
@@ -1048,6 +1094,9 @@ libxlDomainStart(libxlDriverPrivatePtr driver, virDomainObjPtr vm,
     vm->def->id = -1;
     virDomainObjSetState(vm, VIR_DOMAIN_SHUTOFF, VIR_DOMAIN_SHUTOFF_FAILED);
 
+ release_dom:
+    virDomainLockProcessPause(driver->lockManager, vm, &priv->lockState);
+
  cleanup:
     libxl_domain_config_dispose(&d_config);
     VIR_FREE(dom_xml);

src/libxl/libxl_domain.h

@@ -64,6 +64,7 @@ struct _libxlDomainObjPrivate {
     virChrdevsPtr devs;
     libxl_evgen_domain_death *deathW;
     unsigned short migrationPort;
+    char *lockState;
 
     struct libxlDomainJobObj job;
 };

src/libxl/libxl_driver.c

@@ -57,6 +57,7 @@
 #include "viratomic.h"
 #include "virhostdev.h"
 #include "network/bridge_driver.h"
+#include "locking/domain_lock.h"
 
 #define VIR_FROM_THIS VIR_FROM_LIBXL
 
@@ -411,6 +412,7 @@ libxlStateCleanup(void)
     virObjectUnref(libxl_driver->domains);
     virObjectUnref(libxl_driver->reservedVNCPorts);
     virObjectUnref(libxl_driver->migrationPorts);
+    virLockManagerPluginUnref(libxl_driver->lockManager);
 
     virObjectEventStateFree(libxl_driver->domainEventState);
     virSysinfoDefFree(libxl_driver->hostsysinfo);
@@ -590,6 +592,14 @@ libxlStateInitialize(bool privileged,
         goto error;
     }
 
+    if (!(libxl_driver->lockManager =
+          virLockManagerPluginNew(cfg->lockManagerName ?
+                                  cfg->lockManagerName : "nop",
+                                  "libxl",
+                                  cfg->configBaseDir,
+                                  0)))
+        goto error;
+
     /* read the host sysinfo */
     libxl_driver->hostsysinfo = virSysinfoRead();
 
@@ -2859,11 +2869,21 @@ libxlDomainAttachDeviceDiskLive(virDomainObjPtr vm, virDomainDeviceDefPtr dev)
                 if (libxlMakeDisk(l_disk, &x_disk) < 0)
                     goto cleanup;
 
+                if (virDomainLockDiskAttach(libxl_driver->lockManager,
+                                            "xen:///system",
+                                            vm, l_disk) < 0)
+                    goto cleanup;
+
                 if ((ret = libxl_device_disk_add(cfg->ctx, vm->def->id,
                                                 &x_disk, NULL)) < 0) {
                     virReportError(VIR_ERR_INTERNAL_ERROR,
                                    _("libxenlight failed to attach disk '%s'"),
                                    l_disk->dst);
+                    if (virDomainLockDiskDetach(libxl_driver->lockManager,
+                                                vm, l_disk) < 0) {
+                        VIR_WARN("Unable to release lock on %s",
+                                 virDomainDiskGetSource(l_disk));
+                    }
                     goto cleanup;
                 }
 
@@ -3004,6 +3024,11 @@ libxlDomainDetachDeviceDiskLive(virDomainObjPtr vm, virDomainDeviceDefPtr dev)
                     goto cleanup;
                 }
 
+                if (virDomainLockDiskDetach(libxl_driver->lockManager,
+                                            vm, l_disk) < 0)
+                    VIR_WARN("Unable to release lock on %s",
+                             virDomainDiskGetSource(l_disk));
+
                 virDomainDiskRemove(vm->def, idx);
                 virDomainDiskDefFree(l_disk);
 

src/libxl/libxl_migration.c

@@ -41,6 +41,7 @@
 #include "libxl_driver.h"
 #include "libxl_conf.h"
 #include "libxl_migration.h"
+#include "locking/domain_lock.h"
 
 #define VIR_FROM_THIS VIR_FROM_LIBXL
 
@@ -469,6 +470,7 @@ libxlDomainMigrationPerform(libxlDriverPrivatePtr driver,
                             const char *dname ATTRIBUTE_UNUSED,
                             unsigned int flags)
 {
+    libxlDomainObjPrivatePtr priv = vm->privateData;
     char *hostname = NULL;
     unsigned short port = 0;
     char portstr[100];
@@ -503,6 +505,10 @@ libxlDomainMigrationPerform(libxlDriverPrivatePtr driver,
     sockfd = virNetSocketDupFD(sock, true);
     virObjectUnref(sock);
 
+    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));
+
     /* suspend vm and send saved data to dst through socket fd */
     virObjectUnlock(vm);
     ret = libxlDoMigrateSend(driver, vm, flags, sockfd);

src/libxl/test_libvirtd_libxl.aug.in

@@ -3,3 +3,4 @@ module Test_libvirtd_libxl =
 
    test Libvirtd_libxl.lns get conf =
 { "autoballoon" = "1" }
+{ "lock_manager" = "lockd" }