From 5b40c5f5294964fc09df2c8332ab63cd2d729264 Mon Sep 17 00:00:00 2001
From: Jeffrey Altman <jaltman@your-file-system.com>
Date: Sat, 13 Aug 2011 14:35:53 -0400
Subject: [PATCH] Windows: Insert Server Reference List changes

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 | 78 ++++++++++++++++++++++++++++++++++----
 1 file changed, 71 insertions(+), 7 deletions(-)

diff --git a/src/WINNT/afsd/cm_server.c b/src/WINNT/afsd/cm_server.c
index 963c05d4ae..b7a40810ef 100644
--- a/src/WINNT/afsd/cm_server.c
+++ b/src/WINNT/afsd/cm_server.c
@@ -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);
 }
 /*