ubik: avoid early DISK_Begin calls we know will fail

[openafs.git] / src / ubik / beacon.c

diff --git a/src/ubik/beacon.c b/src/ubik/beacon.c
index a3a48d6..bf32432 100644 (file)
--- a/src/ubik/beacon.c
+++ b/src/ubik/beacon.c
@@ -119,6 +119,7 @@ amSyncSite(void)
            if (beacon_globals.ubik_amSyncSite)
                ubik_dprint("Ubik: I am no longer the sync site\n");
            beacon_globals.ubik_amSyncSite = 0;
+           beacon_globals.ubik_syncSiteAdvertised = 0;
            rcode = 0;
        } else {
            rcode = 1;          /* otherwise still have the required votes */
@@ -159,6 +160,32 @@ ubeacon_AmSyncSite(void)
 }
 
 /*!
+ * \brief Determine whether at least quorum are aware we have a sync-site.
+ *
+ * Called from higher-level modules.
+ *
+ * There is a gap between the time when a new sync-site is elected and the time
+ * when the remotes are aware of that. Therefore, any write transaction between
+ * this gap will fail. This will force a new re-election which might be time
+ * consuming. This procedure determines whether the remotes (quorum) are aware
+ * we have a sync-site.
+ *
+ * \return 1 if remotes are aware we have a sync-site
+ * \return 0 if remotes are not aware we have a sync-site
+ */
+int
+ubeacon_SyncSiteAdvertised(void)
+{
+    afs_int32 rcode;
+
+    UBIK_BEACON_LOCK;
+    rcode = beacon_globals.ubik_syncSiteAdvertised;
+    UBIK_BEACON_UNLOCK;
+
+    return rcode;
+}
+
+/*!
  * \see ubeacon_InitServerListCommon()
  */
 int
@@ -371,6 +398,7 @@ ubeacon_InitServerListCommon(afs_uint32 ame, struct afsconf_cell *info,
        if (nServers == 1 && !amIClone) {
            beacon_globals.ubik_amSyncSite = 1; /* let's start as sync site */
            beacon_globals.syncSiteUntil = 0x7fffffff;  /* and be it quite a while */
+           beacon_globals.ubik_syncSiteAdvertised = 1;
        }
     } else {
        if (nServers == 1)      /* special case 1 server */
@@ -382,6 +410,7 @@ ubeacon_InitServerListCommon(afs_uint32 ame, struct afsconf_cell *info,
            ubik_dprint("Ubik: I am the sync site - 1 server\n");
        beacon_globals.ubik_amSyncSite = 1;
        beacon_globals.syncSiteUntil = 0x7fffffff;      /* quite a while */
+       beacon_globals.ubik_syncSiteAdvertised = 1;
     }
     return 0;
 }
@@ -579,6 +608,11 @@ ubeacon_Interact(void *dummy)
            UBIK_BEACON_LOCK;
            if (!beacon_globals.ubik_amSyncSite)
                ubik_dprint("Ubik: I am the sync site\n");
+           else {
+               /* at this point, we have the guarantee that at least quorum
+                * received a beacon packet informing we have a sync-site. */
+               beacon_globals.ubik_syncSiteAdvertised = 1;
+           }
            beacon_globals.ubik_amSyncSite = 1;
            beacon_globals.syncSiteUntil = oldestYesVote + SMALLTIME;
 #ifndef AFS_PTHREAD_ENV
@@ -592,6 +626,7 @@ ubeacon_Interact(void *dummy)
            if (beacon_globals.ubik_amSyncSite)
                ubik_dprint("Ubik: I am no longer the sync site\n");
            beacon_globals.ubik_amSyncSite = 0;
+           beacon_globals.ubik_syncSiteAdvertised = 0;
            UBIK_BEACON_UNLOCK;
            DBHOLD(ubik_dbase);
            urecovery_ResetState();     /* tell recovery we're no longer the sync site */