【bugfix】修复按需回放redo阶段备机读业务同时触发reform，导主节点死锁，最后报错退出的问题

src/gausskernel/ddes/adapter/ss_dms_bufmgr.cpp

@@ -553,6 +553,9 @@ bool SSOndemandRequestPrimaryRedo(BufferTag tag)
         return false;
     } else if (SS_STANDBY_ONDEMAND_NORMAL || SS_PRIMARY_MODE) {
         return true;
+    // retry after reform finish
+    } else if (SS_IN_REFORM) {
+        return false;
     }
 
     ereport(DEBUG1,

src/gausskernel/ddes/adapter/ss_dms_callback.cpp

@@ -2171,6 +2171,16 @@ int CBOndemandRedoPageForStandby(void *block_key, int32 *redo_status)
         return GS_SUCCESS;;
     }
 
+    if (SS_IN_REFORM) {
+        ereport(WARNING, (errmodule(MOD_DMS),
+            errmsg("[SS][On-demand][%u/%u/%u/%d %d-%u] Reform happend when primary redo page for standby,"
+            "return ONDEMAND_REDO_FAIL.",
+            tag->rnode.spcNode, tag->rnode.dbNode,
+            tag->rnode.relNode, tag->rnode.bucketNode, tag->forkNum, tag->blockNum)));
+        *redo_status = ONDEMAND_REDO_FAIL;
+        return GS_SUCCESS;
+    }
+
     Buffer buffer = InvalidBuffer;
     uint32 saveInterruptHoldoffCount = t_thrd.int_cxt.InterruptHoldoffCount;
     *redo_status = ONDEMAND_REDO_DONE;

src/gausskernel/storage/buffer/bufmgr.cpp

@@ -6357,11 +6357,11 @@ retry:
              * hold the content shared lock all the time, give the MES from the primary a chance to get it,
              * and the timeout time of the primary and standby servers is modified to open the unlocking
              * time window.
-	     */
+            */
             if (!dms_standby_retry_read && SS_STANDBY_MODE) {
-	        dms_standby_retry_read = true;
-		mode = BUFFER_LOCK_EXCLUSIVE;
-	    }
+                dms_standby_retry_read = true;
+                mode = BUFFER_LOCK_EXCLUSIVE;
+            }
             pg_usleep(5000L);
             goto retry;
         } else if (dms_standby_retry_read) {
@@ -6371,11 +6371,11 @@ retry:
              *
              * A good idea would be to add the ability to lock downgrade for LWLock.
              */
-	    mode = origin_mode;
-	    dms_standby_retry_read = false;
-	    LWLockRelease(buf->content_lock);
-	    goto retry;
-	}
+            mode = origin_mode;
+            dms_standby_retry_read = false;
+            LWLockRelease(buf->content_lock);
+            goto retry;
+        }
     }
 
 }