win-power-mgmt-flush-test-20041003

The windows power management code responds to a request to suspend or
hibernate by performing a "fs flushvol" as the logged in user on each
of the SMB/CIFS mounted shares.  This can be very time consuming if
the cell servers cannot be reached.

This patch adds a test to ensure that there is at least one network
adapter in the machine which is not a loopback adapter.

While developing this patch other areas of concern have been raised.
The power management code waits a fixed period of time based upon
the hard dead timeout before allowing the suspend/hibernate to continue.
This allows the machine to shutdown even if there are active flush
operations being performed.  This defeats the benefit of performing
the flush at all.

A better mechanism could be developed if the functions called via
cm_IoctlFlushVolume returned and checked error codes.  Then it might
be possible to abandon the flush operation if a Server Not Reachable
state was obtained.

The power management flush operations will also not work on Terminal
Server.  This would be important in the case where a terminal server
is shutting down due to a switch over to a UPS.  The reason it does
not work on Terminal Server is that there is that it is not possible
for afsd_service.exe to enumerate the SMB/CIFS shares and impersonate
the individual logged in users.

It would be preferred for there to be a new cm_FlushAll() function
implemented which was not dependent on the use of the ioctl mechanism
for the purpose of identifying a volume ID or a user ID.

src/WINNT/afsd/afsd_flushvol.c

@@ -27,6 +27,9 @@
 
 #include "afsd_flushvol.h"
 #include "afsd_eventlog.h"
+#include "lanahelper.h"
+
+extern void afsi_log(char *pattern, ...);
 
 static FLUSHVOLTHREADINFO	gThreadInfo   = {0};
 static HANDLE			gThreadHandle = NULL;
@@ -48,6 +51,7 @@ afsd_ServicePerformFlushVolumeCmd(char *data)
     register afs_int32 code;
     struct ViceIoctl blob;
 
+    afsi_log("Flushing Volume \"%s\"",data);
     memset(&blob, '\0', sizeof(blob));
     code = pioctl(data, VIOC_FLUSHVOLUME, &blob, 0);
     
@@ -74,6 +78,11 @@ afsd_ServicePerformFlushVolumes()
     PCHAR		pszShareName, pc;
     afs_int32	afsRet = 0;
 
+    if ( lana_OnlyLoopback() ) {
+        // Nothing to do if we only have a loopback interface
+        return TRUE;
+    }
+
     // Determine the root share name (\\AFS\ALL or \\<machine>-AFS\ALL),
     // and the length of the server name prefix.
     pszShareName = smb_GetSharename();
@@ -143,8 +152,7 @@ afsd_ServicePerformFlushVolumes()
             {
                 // got one!
                 // but we don't want to flush '\\[...]afs\all'
-				if (_stricmp(lpnr->lpRemoteName,
-					     pszShareName) == 0)
+                if (_stricmp(lpnr->lpRemoteName, pszShareName) == 0)
                     continue;
                 ++dwTotalVols;
 

src/WINNT/afsd/afsd_service.c

@@ -32,7 +32,8 @@
 // The following is defined if you want to receive Power notifications,
 // including Hibernation, and also subsequent flushing of AFS volumes
 //
-#define REGISTER_POWER_NOTIFICATIONS
+#define REGISTER_POWER_NOTIFICATIONS 1
+#define FLUSH_VOLUME                 1
 //
 // Check
 */
@@ -130,7 +131,6 @@ afsd_ServiceFlushVolume(DWORD dwlpEventData)
     {
         dwRet = NO_ERROR;
     }
-
     else
     {
         /* flush was unsuccessful, or timeout - deny shutdown */
@@ -276,7 +276,7 @@ afsd_ServiceControlHandlerEx(
             case PBT_APMQUERYSUSPEND:                                                         
             case PBT_APMQUERYSTANDBY:                                                         
 
-#ifdef	REGISTER_POWER_NOTIFICATIONS				                                      
+#ifdef	FLUSH_VOLUME
                 /* handle event */                                                            
                 dwRet = afsd_ServiceFlushVolume((DWORD) lpEventData);                         
 #else                                                                                       

src/WINNT/afsd/lanahelper.cpp

@@ -394,6 +394,35 @@ extern "C" lana_number_t lana_FindLoopback(void)
     return LANA_INVALID;
 }
 
+/* Returns TRUE if all adapters are loopback adapters */
+extern "C" BOOL lana_OnlyLoopback(void)
+{
+    NCB ncb;
+    LANA_ENUM lana_list;
+    int status;
+    int i;
+
+    memset(&ncb, 0, sizeof(ncb));
+    ncb.ncb_command = NCBENUM;
+    ncb.ncb_buffer = (UCHAR *) &lana_list;
+    ncb.ncb_length = sizeof(lana_list);
+    status = Netbios(&ncb);
+    if (status != 0) {
+#ifndef NOLOGGING
+        afsi_log("Netbios NCBENUM failed: status %ld", status);
+#endif
+        return FALSE;
+    }
+    for (i = 0; i < lana_list.length; i++) {
+	if (!lana_IsLoopback(lana_list.lana[i])) {
+	    // Found one non-Loopback adapter
+	    return FALSE;
+	}
+    }
+    // All adapters are loopback
+    return TRUE;
+}
+
 // Is the given lana a Windows Loopback Adapter?
 // TODO: implement a better check for loopback
 // TODO: also check for proper bindings (IPv4)

src/WINNT/afsd/lanahelper.h

@@ -59,6 +59,8 @@ extern "C" {
 
   lana_number_t lana_FindLoopback(void);
 
+  BOOL lana_OnlyLoopback(void);
+
   BOOL lana_IsLoopback(lana_number_t lana);
 
   long lana_GetUncServerNameEx(char *buffer, lana_number_t * pLana, int * pIsGateway, int flags);