DAFS: Avoid unnecessary preattach on FSYNC_VOL_ON

FSYNC_VOL_ON/FSYNC_VOL_ATTACH can be called to "online" a volume that
was actually kept online for the duration of the volume operation.
Avoid calling VPreAttachVolumeByVp_r for such a volume if it's already
attached, in order to avoid an unnecessary log message and to save a
tiny bit of processing.

Change-Id: I7776b933599ec0488941ccbd9a8e1279f5a552f4
Reviewed-on: http://gerrit.openafs.org/6167
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@dementix.org>

diff --git a/src/vol/fssync-server.c b/src/vol/fssync-server.c
index d8f274c..14d2247 100644 (file)
--- a/src/vol/fssync-server.c
+++ b/src/vol/fssync-server.c
@@ -751,10 +751,25 @@ FSYNC_com_VolOn(FSSYNC_VolOp_command * vcom, SYNC_response * res)
     }
 
 #ifdef AFS_DEMAND_ATTACH_FS
-    /* first, check to see whether we have such a volume defined */
-    vp = VPreAttachVolumeById_r(&error,
-                               vcom->vop->partName,
-                               vcom->vop->volume);
+
+    if (vp &&
+        FSYNC_partMatch(vcom, vp, 0) &&
+        vp->pending_vol_op &&
+        vp->pending_vol_op->vol_op_state == FSSYNC_VolOpRunningOnline &&
+        V_attachState(vp) == VOL_STATE_ATTACHED) {
+
+       /* noop; the volume stayed online for the volume operation and we were
+        * simply told that the vol op is done. The vp we already have is fine,
+        * so avoid confusing volume routines with trying to preattach an
+        * attached volume. */
+
+    } else {
+       /* first, check to see whether we have such a volume defined */
+       vp = VPreAttachVolumeById_r(&error,
+                                   vcom->vop->partName,
+                                   vcom->vop->volume);
+    }
+
     if (vp) {
        VCreateReservation_r(vp);
        VWaitExclusiveState_r(vp);