Windows: Insert Server Reference List changes
authorJeffrey Altman <jaltman@your-file-system.com>
Sat, 13 Aug 2011 18:35:53 +0000 (14:35 -0400)
committerDerrick Brashear <shadow@dementix.org>
Sun, 14 Aug 2011 02:06:52 +0000 (19:06 -0700)
When inserting a new cm_serverRef_t object into a server list
perform the following operations:

1. take advantage of the fact that the cm_serverLock is held
   exclusively to purge the list of any deleted entries that
   could not be removed previously.

2. check to ensure that the item that is being added does not
   already exist in the list.  If it does, discard it.

Change-Id: Ibabfc3b2e1b716f2a0cc664a4667bc9219fde09c
Reviewed-on: http://gerrit.openafs.org/5258
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Tested-by: Jeffrey Altman <jaltman@openafs.org>
Reviewed-by: Jeffrey Altman <jaltman@openafs.org>
Reviewed-by: Derrick Brashear <shadow@dementix.org>

src/WINNT/afsd/cm_server.c

index 963c05d..b7a4081 100644 (file)
@@ -1075,27 +1075,91 @@ void cm_InsertServerList(cm_serverRef_t** list, cm_serverRef_t* element)
     unsigned short ipRank;
 
     lock_ObtainWrite(&cm_serverLock);
-    current=*list;
-    ipRank = element->server->ipRank;
+    /*
+     * Since we are grabbing the serverLock exclusively remove any
+     * deleted serverRef objects with a zero refcount before
+     * inserting the new item.
+     */
+    if (*list) {
+        cm_serverRef_t  **currentp = list;
+        cm_serverRef_t  **nextp = NULL;
+        cm_serverRef_t  * next = NULL;
+
+        for (currentp = list; *currentp; currentp = nextp)
+        {
+            nextp = &(*currentp)->next;
+            if ((*currentp)->refCount == 0 &&
+                (*currentp)->status == srv_deleted) {
+                next = *nextp;
+
+                if ((*currentp)->volID)
+                    cm_RemoveVolumeFromServer((*currentp)->server, (*currentp)->volID);
+                cm_FreeServer((*currentp)->server);
+                free(*currentp);
+                nextp = &next;
+            }
+        }
+    }
 
     /* insertion into empty list  or at the beginning of the list */
-    if ( !current || (current->server->ipRank > ipRank) )
+    if (!(*list))
+    {
+        element->next = NULL;
+        *list = element;
+        goto done;
+    }
+
+    /*
+     * Now that deleted entries have been removed and we know that the
+     * list was not empty, look for duplicates.  If the element we are
+     * inserting already exists, discard it.
+     */
+    for ( current = *list; current; current = current->next)
+    {
+        cm_server_t * server1 = current->server;
+        cm_server_t * server2 = element->server;
+
+        if (current->status == srv_deleted)
+            continue;
+
+        if (server1->type != server2->type)
+            continue;
+
+        if (server1->addr.sin_addr.s_addr != server2->addr.sin_addr.s_addr)
+            continue;
+
+        if ((server1->flags & CM_SERVERFLAG_UUID) != (server2->flags & CM_SERVERFLAG_UUID))
+            continue;
+
+        if ((server1->flags & CM_SERVERFLAG_UUID) &&
+            !afs_uuid_equal(&server1->uuid, &server2->uuid))
+            continue;
+
+        /* we must have a match, discard the new element */
+        free(element);
+        goto done;
+    }
+
+    ipRank = element->server->ipRank;
+
+       /* insertion at the beginning of the list */
+    if ((*list)->server->ipRank > ipRank)
     {
         element->next = *list;
         *list = element;
-        lock_ReleaseWrite(&cm_serverLock);
-        return ;
+        goto done;
     }
 
-    while ( current->next ) /* find appropriate place to insert */
+    /* find appropriate place to insert */
+    for ( current = *list; current->next; current = current->next)
     {
         if ( current->next->server->ipRank > ipRank )
             break;
-        else current = current->next;
     }
     element->next = current->next;
     current->next = element;
 
+  done:
     lock_ReleaseWrite(&cm_serverLock);
 }
 /*