Fix checksums for CLUSTER, VACUUM FULL etc.

In CLUSTER, VACUUM FULL and ALTER TABLE SET TABLESPACE
I erroneously set checksum before log_newpage, which
sets the LSN and invalidates the checksum. So set
checksum immediately *after* log_newpage.

Bug report Fujii Masao, Fix and patch by Jeff Davis

src/backend/access/heap/rewriteheap.c

@@ -273,14 +273,15 @@ end_heap_rewrite(RewriteState state)
 	/* Write the last page, if any */
 	if (state->rs_buffer_valid)
 	{
-		PageSetChecksumInplace(state->rs_buffer, state->rs_blockno);
-
 		if (state->rs_use_wal)
 			log_newpage(&state->rs_new_rel->rd_node,
 						MAIN_FORKNUM,
 						state->rs_blockno,
 						state->rs_buffer);
 		RelationOpenSmgr(state->rs_new_rel);
+
+		PageSetChecksumInplace(state->rs_buffer, state->rs_blockno);
+
 		smgrextend(state->rs_new_rel->rd_smgr, MAIN_FORKNUM, state->rs_blockno,
 				   (char *) state->rs_buffer, true);
 	}
@@ -616,8 +617,6 @@ raw_heap_insert(RewriteState state, HeapTuple tup)
 		{
 			/* Doesn't fit, so write out the existing page */
 
-			PageSetChecksumInplace(page, state->rs_blockno);
-
 			/* XLOG stuff */
 			if (state->rs_use_wal)
 				log_newpage(&state->rs_new_rel->rd_node,
@@ -632,6 +631,9 @@ raw_heap_insert(RewriteState state, HeapTuple tup)
 			 * end_heap_rewrite.
 			 */
 			RelationOpenSmgr(state->rs_new_rel);
+
+			PageSetChecksumInplace(page, state->rs_blockno);
+
 			smgrextend(state->rs_new_rel->rd_smgr, MAIN_FORKNUM,
 					   state->rs_blockno, (char *) page, true);
 

src/backend/commands/tablecmds.c

@@ -51,6 +51,7 @@
 #include "commands/tablespace.h"
 #include "commands/trigger.h"
 #include "commands/typecmds.h"
+#include "common/relpath.h"
 #include "executor/executor.h"
 #include "foreign/foreign.h"
 #include "miscadmin.h"
@@ -8902,12 +8903,21 @@ copy_relation_data(SMgrRelation src, SMgrRelation dst,
 
 		smgrread(src, forkNum, blkno, buf);
 
-		PageSetChecksumInplace(page, blkno);
+		if (!PageIsVerified(page, blkno))
+			ereport(ERROR,
+					(errcode(ERRCODE_DATA_CORRUPTED),
+					 errmsg("invalid page in block %u of relation %s",
+							blkno,
+							relpathbackend(src->smgr_rnode.node,
+										   src->smgr_rnode.backend,
+										   forkNum))));
 
 		/* XLOG stuff */
 		if (use_wal)
 			log_newpage(&dst->smgr_rnode.node, forkNum, blkno, page);
 
+		PageSetChecksumInplace(page, blkno);
+
 		/*
 		 * Now write the page.	We say isTemp = true even if it's not a temp
 		 * rel, because there's no need for smgr to schedule an fsync for this