Modify BufferGetPage() to prepare for "snapshot too old" feature

This patch is a no-op patch which is intended to reduce the chances
of failures of omission once the functional part of the "snapshot
too old" patch goes in.  It adds parameters for snapshot, relation,
and an enum to specify whether the snapshot age check needs to be
done for the page at this point.  This initial patch passes NULL
for the first two new parameters and BGP_NO_SNAPSHOT_TEST for the
third.  The follow-on patch will change the places where the test
needs to be made.

10 files changed, 30 insertions, 21 deletions

diff --git a/contrib/bloom/blinsert.c b/contrib/bloom/blinsert.c
index 6eecb12187d..cc12808375b 100644
--- a/contrib/bloom/blinsert.c
+++ b/contrib/bloom/blinsert.c
@@ -204,7 +204,8 @@ blinsert(Relation index, Datum *values, bool *isnull,
 	 */
 	metaBuffer = ReadBuffer(index, BLOOM_METAPAGE_BLKNO);
 	LockBuffer(metaBuffer, BUFFER_LOCK_SHARE);
-	metaData = BloomPageGetMeta(BufferGetPage(metaBuffer));
+	metaData = BloomPageGetMeta(BufferGetPage(metaBuffer, NULL, NULL,
+											  BGP_NO_SNAPSHOT_TEST));
 
 	if (metaData->nEnd > metaData->nStart)
 	{
diff --git a/contrib/bloom/blscan.c b/contrib/bloom/blscan.c
index ba137835494..ae937f66710 100644
--- a/contrib/bloom/blscan.c
+++ b/contrib/bloom/blscan.c
@@ -138,7 +138,7 @@ blgetbitmap(IndexScanDesc scan, TIDBitmap *tbm)
 									blkno, RBM_NORMAL, bas);
 
 		LockBuffer(buffer, BUFFER_LOCK_SHARE);
-		page = BufferGetPage(buffer);
+		page = BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 
 		if (!BloomPageIsDeleted(page))
 		{
diff --git a/contrib/bloom/blutils.c b/contrib/bloom/blutils.c
index 76d6ba80222..6c7dc1d07d1 100644
--- a/contrib/bloom/blutils.c
+++ b/contrib/bloom/blutils.c
@@ -139,11 +139,12 @@ initBloomState(BloomState *state, Relation index)
 		buffer = ReadBuffer(index, BLOOM_METAPAGE_BLKNO);
 		LockBuffer(buffer, BUFFER_LOCK_SHARE);
 
-		page = BufferGetPage(buffer);
+		page = BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 
 		if (!BloomPageIsMeta(page))
 			elog(ERROR, "Relation is not a bloom index");
-		meta = BloomPageGetMeta(BufferGetPage(buffer));
+		meta = BloomPageGetMeta(BufferGetPage(buffer, NULL, NULL,
+											  BGP_NO_SNAPSHOT_TEST));
 
 		if (meta->magickNumber != BLOOM_MAGICK_NUMBER)
 			elog(ERROR, "Relation is not a bloom index");
@@ -315,7 +316,8 @@ BloomNewBuffer(Relation index)
 		 */
 		if (ConditionalLockBuffer(buffer))
 		{
-			Page		page = BufferGetPage(buffer);
+			Page		page = BufferGetPage(buffer, NULL, NULL,
+											 BGP_NO_SNAPSHOT_TEST);
 
 			if (PageIsNew(page))
 				return buffer;	/* OK to use, if never initialized */
diff --git a/contrib/bloom/blvacuum.c b/contrib/bloom/blvacuum.c
index 19c010c2524..ee40ebbd973 100644
--- a/contrib/bloom/blvacuum.c
+++ b/contrib/bloom/blvacuum.c
@@ -194,7 +194,7 @@ blvacuumcleanup(IndexVacuumInfo *info, IndexBulkDeleteResult *stats)
 		buffer = ReadBufferExtended(index, MAIN_FORKNUM, blkno,
 									RBM_NORMAL, info->strategy);
 		LockBuffer(buffer, BUFFER_LOCK_SHARE);
-		page = (Page) BufferGetPage(buffer);
+		page = BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 
 		if (BloomPageIsDeleted(page))
 		{
diff --git a/contrib/pageinspect/btreefuncs.c b/contrib/pageinspect/btreefuncs.c
index d088ce57197..cdeffe3e013 100644
--- a/contrib/pageinspect/btreefuncs.c
+++ b/contrib/pageinspect/btreefuncs.c
@@ -90,7 +90,7 @@ typedef struct BTPageStat
 static void
 GetBTPageStatistics(BlockNumber blkno, Buffer buffer, BTPageStat *stat)
 {
-	Page		page = BufferGetPage(buffer);
+	Page		page = BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 	PageHeader	phdr = (PageHeader) page;
 	OffsetNumber maxoff = PageGetMaxOffsetNumber(page);
 	BTPageOpaque opaque = (BTPageOpaque) PageGetSpecialPointer(page);
@@ -317,7 +317,9 @@ bt_page_items(PG_FUNCTION_ARGS)
 		uargs = palloc(sizeof(struct user_args));
 
 		uargs->page = palloc(BLCKSZ);
-		memcpy(uargs->page, BufferGetPage(buffer), BLCKSZ);
+		memcpy(uargs->page,
+			   BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST),
+			   BLCKSZ);
 
 		UnlockReleaseBuffer(buffer);
 		relation_close(rel, AccessShareLock);
@@ -447,7 +449,7 @@ bt_metap(PG_FUNCTION_ARGS)
 	buffer = ReadBuffer(rel, 0);
 	LockBuffer(buffer, BUFFER_LOCK_SHARE);
 
-	page = BufferGetPage(buffer);
+	page = BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 	metad = BTPageGetMeta(page);
 
 	/* Build a tuple descriptor for our result type */
diff --git a/contrib/pageinspect/rawpage.c b/contrib/pageinspect/rawpage.c
index 71d0c8d2ca9..139419ae1a4 100644
--- a/contrib/pageinspect/rawpage.c
+++ b/contrib/pageinspect/rawpage.c
@@ -147,7 +147,9 @@ get_raw_page_internal(text *relname, ForkNumber forknum, BlockNumber blkno)
 	buf = ReadBufferExtended(rel, forknum, blkno, RBM_NORMAL, NULL);
 	LockBuffer(buf, BUFFER_LOCK_SHARE);
 
-	memcpy(raw_page_data, BufferGetPage(buf), BLCKSZ);
+	memcpy(raw_page_data,
+		   BufferGetPage(buf, NULL, NULL, BGP_NO_SNAPSHOT_TEST),
+		   BLCKSZ);
 
 	LockBuffer(buf, BUFFER_LOCK_UNLOCK);
 	ReleaseBuffer(buf);
diff --git a/contrib/pg_visibility/pg_visibility.c b/contrib/pg_visibility/pg_visibility.c
index 5e5c7cce244..4a626c23643 100644
--- a/contrib/pg_visibility/pg_visibility.c
+++ b/contrib/pg_visibility/pg_visibility.c
@@ -107,7 +107,7 @@ pg_visibility(PG_FUNCTION_ARGS)
 	buffer = ReadBuffer(rel, blkno);
 	LockBuffer(buffer, BUFFER_LOCK_SHARE);
 
-	page = BufferGetPage(buffer);
+	page = BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 	values[2] = BoolGetDatum(PageIsAllVisible(page));
 
 	UnlockReleaseBuffer(buffer);
@@ -333,7 +333,7 @@ collect_visibility_data(Oid relid, bool include_pd)
 										bstrategy);
 			LockBuffer(buffer, BUFFER_LOCK_SHARE);
 
-			page = BufferGetPage(buffer);
+			page = BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 			if (PageIsAllVisible(page))
 				info->bits[blkno] |= (1 << 2);
 
diff --git a/contrib/pgstattuple/pgstatapprox.c b/contrib/pgstattuple/pgstatapprox.c
index a49ff543d2d..b7734fac887 100644
--- a/contrib/pgstattuple/pgstatapprox.c
+++ b/contrib/pgstattuple/pgstatapprox.c
@@ -100,7 +100,7 @@ statapprox_heap(Relation rel, output_type *stat)
 
 		LockBuffer(buf, BUFFER_LOCK_SHARE);
 
-		page = BufferGetPage(buf);
+		page = BufferGetPage(buf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 
 		/*
 		 * It's not safe to call PageGetHeapFreeSpace() on new pages, so we
diff --git a/contrib/pgstattuple/pgstatindex.c b/contrib/pgstattuple/pgstatindex.c
index 9f1377c4cd9..4596632c091 100644
--- a/contrib/pgstattuple/pgstatindex.c
+++ b/contrib/pgstattuple/pgstatindex.c
@@ -173,7 +173,7 @@ pgstatindex_impl(Relation rel, FunctionCallInfo fcinfo)
 	 */
 	{
 		Buffer		buffer = ReadBufferExtended(rel, MAIN_FORKNUM, 0, RBM_NORMAL, bstrategy);
-		Page		page = BufferGetPage(buffer);
+		Page		page = BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 		BTMetaPageData *metad = BTPageGetMeta(page);
 
 		indexStat.version = metad->btm_version;
@@ -211,7 +211,7 @@ pgstatindex_impl(Relation rel, FunctionCallInfo fcinfo)
 		buffer = ReadBufferExtended(rel, MAIN_FORKNUM, blkno, RBM_NORMAL, bstrategy);
 		LockBuffer(buffer, BUFFER_LOCK_SHARE);
 
-		page = BufferGetPage(buffer);
+		page = BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 		opaque = (BTPageOpaque) PageGetSpecialPointer(page);
 
 		/* Determine page type, and update totals */
@@ -399,7 +399,7 @@ pgstatginindex(PG_FUNCTION_ARGS)
 	 */
 	buffer = ReadBuffer(rel, GIN_METAPAGE_BLKNO);
 	LockBuffer(buffer, GIN_SHARE);
-	page = BufferGetPage(buffer);
+	page = BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 	metadata = GinPageGetMeta(page);
 
 	stats.version = metadata->ginVersion;
diff --git a/contrib/pgstattuple/pgstattuple.c b/contrib/pgstattuple/pgstattuple.c
index c1122b496ad..46655ac01c5 100644
--- a/contrib/pgstattuple/pgstattuple.c
+++ b/contrib/pgstattuple/pgstattuple.c
@@ -320,7 +320,8 @@ pgstat_heap(Relation rel, FunctionCallInfo fcinfo)
 			buffer = ReadBufferExtended(rel, MAIN_FORKNUM, block,
 										RBM_NORMAL, scan->rs_strategy);
 			LockBuffer(buffer, BUFFER_LOCK_SHARE);
-			stat.free_space += PageGetHeapFreeSpace((Page) BufferGetPage(buffer));
+			stat.free_space += PageGetHeapFreeSpace
+				(BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST));
 			UnlockReleaseBuffer(buffer);
 			block++;
 		}
@@ -333,7 +334,8 @@ pgstat_heap(Relation rel, FunctionCallInfo fcinfo)
 		buffer = ReadBufferExtended(rel, MAIN_FORKNUM, block,
 									RBM_NORMAL, scan->rs_strategy);
 		LockBuffer(buffer, BUFFER_LOCK_SHARE);
-		stat.free_space += PageGetHeapFreeSpace((Page) BufferGetPage(buffer));
+		stat.free_space += PageGetHeapFreeSpace
+			(BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST));
 		UnlockReleaseBuffer(buffer);
 		block++;
 	}
@@ -358,7 +360,7 @@ pgstat_btree_page(pgstattuple_type *stat, Relation rel, BlockNumber blkno,
 
 	buf = ReadBufferExtended(rel, MAIN_FORKNUM, blkno, RBM_NORMAL, bstrategy);
 	LockBuffer(buf, BT_READ);
-	page = BufferGetPage(buf);
+	page = BufferGetPage(buf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 
 	/* Page is valid, see what to do with it */
 	if (PageIsNew(page))
@@ -402,7 +404,7 @@ pgstat_hash_page(pgstattuple_type *stat, Relation rel, BlockNumber blkno,
 
 	_hash_getlock(rel, blkno, HASH_SHARE);
 	buf = _hash_getbuf_with_strategy(rel, blkno, HASH_READ, 0, bstrategy);
-	page = BufferGetPage(buf);
+	page = BufferGetPage(buf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 
 	if (PageGetSpecialSize(page) == MAXALIGN(sizeof(HashPageOpaqueData)))
 	{
@@ -447,7 +449,7 @@ pgstat_gist_page(pgstattuple_type *stat, Relation rel, BlockNumber blkno,
 	buf = ReadBufferExtended(rel, MAIN_FORKNUM, blkno, RBM_NORMAL, bstrategy);
 	LockBuffer(buf, GIST_SHARE);
 	gistcheckpage(rel, buf);
-	page = BufferGetPage(buf);
+	page = BufferGetPage(buf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 
 	if (GistPageIsLeaf(page))
 	{