From 565d040f43018c60e8b9c4c8f6194b4f5cee3ce1 Mon Sep 17 00:00:00 2001
From: "Daniel P. Berrange" <berrange@redhat.com>
Date: Tue, 11 Dec 2012 16:39:50 +0000
Subject: [PATCH] Add support for locking based on LVM volume uuid

---
 src/locking/libvirt_lockd.aug         |  1 +
 src/locking/lock_driver_lockd.c       | 38 ++++++++++++++++++++++++++-
 src/locking/lockd.conf                | 14 ++++++++++
 src/locking/test_libvirt_lockd.aug.in |  1 +
 4 files changed, 53 insertions(+), 1 deletion(-)

diff --git a/src/locking/libvirt_lockd.aug b/src/locking/libvirt_lockd.aug
index dafd8f9d0b..3473862796 100644
--- a/src/locking/libvirt_lockd.aug
+++ b/src/locking/libvirt_lockd.aug
@@ -20,6 +20,7 @@ module Libvirt_lockd =
    let entry = bool_entry "auto_disk_leases"
              | bool_entry "require_lease_for_disks"
              | str_entry "file_lockspace_dir"
+	     | str_entry "lvm_lockspace_dir"
    let comment = [ label "#comment" . del /#[ \t]*/ "# " .  store /([^ \t\n][^\n]*)?/ . del /\n/ "\n" ]
    let empty = [ label "#empty" . eol ]
 
diff --git a/src/locking/lock_driver_lockd.c b/src/locking/lock_driver_lockd.c
index aa0f94a464..e9f9071f8b 100644
--- a/src/locking/lock_driver_lockd.c
+++ b/src/locking/lock_driver_lockd.c
@@ -73,6 +73,7 @@ struct _virLockManagerLockDaemonDriver {
     bool requireLeaseForDisks;
 
     char *fileLockSpaceDir;
+    char *lvmLockSpaceDir;
 };
 
 static virLockManagerLockDaemonDriverPtr driver = NULL;
@@ -134,6 +135,17 @@ static int virLockManagerLockDaemonLoadConfig(const char *configFile)
         }
     }
 
+    p = virConfGetValue(conf, "lvm_lockspace_dir");
+    CHECK_TYPE("lvm_lockspace_dir", VIR_CONF_STRING);
+    if (p && p->str) {
+        VIR_FREE(driver->lvmLockSpaceDir);
+        if (!(driver->lvmLockSpaceDir = strdup(p->str))) {
+            virReportOOMError();
+            virConfFree(conf);
+            return -1;
+        }
+    }
+
     p = virConfGetValue(conf, "require_lease_for_disks");
     CHECK_TYPE("require_lease_for_disks", VIR_CONF_LONG);
     if (p)
@@ -371,8 +383,11 @@ static int virLockManagerLockDaemonInit(unsigned int version,
         if (driver->fileLockSpaceDir &&
             virLockManagerLockDaemonSetupLockspace(driver->fileLockSpaceDir) < 0)
             goto error;
-    }
 
+        if (driver->lvmLockSpaceDir &&
+            virLockManagerLockDaemonSetupLockspace(driver->lvmLockSpaceDir) < 0)
+            goto error;
+    }
 
     return 0;
 
@@ -546,6 +561,26 @@ static int virLockManagerLockDaemonAddResource(virLockManagerPtr lock,
             return 0;
         }
 
+        /* XXX we should somehow pass in TYPE=BLOCK info
+         * from the domain_lock code, instead of assuming /dev
+         */
+        if (STRPREFIX(name, "/dev") &&
+            driver->lvmLockSpaceDir) {
+            VIR_DEBUG("Trying to find an LVM UUID for %s", name);
+            if (virStorageFileGetLVMKey(name, &newName) < 0)
+                goto error;
+
+            if (newName) {
+                VIR_DEBUG("Got an LVM UUID %s for %s", newName, name);
+                if (!(newLockspace = strdup(driver->lvmLockSpaceDir)))
+                    goto no_memory;
+                autoCreate = true;
+                break;
+            }
+            virResetLastError();
+            /* Fallback to generic non-block code */
+        }
+
         if (driver->fileLockSpaceDir) {
             if (!(newLockspace = strdup(driver->fileLockSpaceDir)))
                 goto no_memory;
@@ -623,6 +658,7 @@ static int virLockManagerLockDaemonAddResource(virLockManagerPtr lock,
 
 no_memory:
     virReportOOMError();
+error:
     VIR_FREE(newLockspace);
     VIR_FREE(newName);
     return -1;
diff --git a/src/locking/lockd.conf b/src/locking/lockd.conf
index 7545fd97ee..00f9b495e1 100644
--- a/src/locking/lockd.conf
+++ b/src/locking/lockd.conf
@@ -38,3 +38,17 @@
 # storage.
 #
 #file_lockspace_dir = "/var/lib/libvirt/lockd/files"
+
+
+#
+# When using LVM volumes that can be visible across
+# multiple, it is desirable to do locking based on
+# the unique UUID associated with each volume, instead
+# of their paths. Setting this path causes libvirt to
+# do UUID based locking for LVM.
+#
+# Typically this directory would be located on a shared
+# filesystem visible to all hosts accessing the same
+# storage.
+#
+#lvm_lockspace_dir = "/var/lib/libvirt/lockd/lvmvolumes"
diff --git a/src/locking/test_libvirt_lockd.aug.in b/src/locking/test_libvirt_lockd.aug.in
index 2e65af6217..25cba68c07 100644
--- a/src/locking/test_libvirt_lockd.aug.in
+++ b/src/locking/test_libvirt_lockd.aug.in
@@ -5,3 +5,4 @@ module Test_libvirt_lockd =
 { "auto_disk_leases" = "0" }
 { "require_lease_for_disks" = "1" }
 { "file_lockspace_dir" = "/var/lib/libvirt/lockd/files" }
+{ "lvm_lockspace_dir" = "/var/lib/libvirt/lockd/lvmvolumes" }