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 6eecb12187..cc12808375 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 ba13783549..ae937f6671 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 76d6ba8022..6c7dc1d07d 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 19c010c252..ee40ebbd97 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 d088ce5719..cdeffe3e01 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 71d0c8d2ca..139419ae1a 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 5e5c7cce24..4a626c2364 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 a49ff543d2..b7734fac88 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 9f1377c4cd..4596632c09 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 c1122b496a..46655ac01c 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))
 	{