fix confusion in ConveyorBeltVacuum

per report from Dilip Kumar

diff --git a/src/backend/access/conveyor/conveyor.c b/src/backend/access/conveyor/conveyor.c
index c4443c8ca66cd80ccdffe9080955574174aec269..cdea7a420a8194a345a51f2a9265d924cf945ba2 100644 (file)
--- a/src/backend/access/conveyor/conveyor.c
+++ b/src/backend/access/conveyor/conveyor.c
@@ -990,7 +990,7 @@ void
 ConveyorBeltVacuum(ConveyorBelt *cb)
 {
        Buffer          metabuffer;
-       BlockNumber     fsmblock = CONVEYOR_METAPAGE;
+       BlockNumber     fsmblock = InvalidBlockNumber;
        Buffer          fsmbuffer = InvalidBuffer;
        CBSegNo         cleared_segno = CB_INVALID_SEGMENT;
        bool            needs_xlog;
@@ -1033,10 +1033,10 @@ ConveyorBeltVacuum(ConveyorBelt *cb)
                 * segment.
                 */
                if ((obsolete_state != CBM_OBSOLETE_METAPAGE_ENTRIES ||
-                       metapage_segno != cleared_segno) && fsmblock != CONVEYOR_METAPAGE)
+                       metapage_segno != cleared_segno) && fsmblock != InvalidBlockNumber)
                {
                        UnlockReleaseBuffer(fsmbuffer);
-                       fsmblock = CONVEYOR_METAPAGE;
+                       fsmblock = InvalidBlockNumber;
                        fsmbuffer = InvalidBuffer;
                }
 
@@ -1088,9 +1088,7 @@ ConveyorBeltVacuum(ConveyorBelt *cb)
                                 * we must do this before relocking the metapage.
                                 */
                                fsmblock = ConveyorBeltFSMBlockNumber(cb, cleared_segno);
-                               if (fsmblock == CONVEYOR_METAPAGE)
-                                       fsmbuffer = metabuffer;
-                               else
+                               if (fsmblock != InvalidBlockNumber)
                                        fsmbuffer = ConveyorBeltRead(cb, fsmblock,
                                                                                                 BUFFER_LOCK_EXCLUSIVE);
 
@@ -1282,7 +1280,7 @@ ConveyorBeltExtend(ConveyorBelt *cb, BlockNumber blkno,
 /*
  * Figure out where the FSM bit for a given segment number is located.
  *
- * Returns CONVEYOR_METAPAGE if the segment's FSM bit is in the metapage,
+ * Returns InvalidBlockNumber if the segment's FSM bit is in the metapage,
  * or otherwise the block number of the FSM page that contains that FSM bit.
  */
 BlockNumber
@@ -1293,7 +1291,7 @@ ConveyorBeltFSMBlockNumber(ConveyorBelt *cb, CBSegNo segno)
        unsigned        whichfsmpage;
 
        if (segno < CB_FSM_SEGMENTS_FOR_METAPAGE)
-               return CONVEYOR_METAPAGE;
+               return InvalidBlockNumber;
 
        firstblkno = cb_first_fsm_block(cb->cb_pages_per_segment);
        stride = cb_fsm_block_spacing(cb->cb_pages_per_segment);