From 44965db6004a8fce320ac09519e4b49d7243ae40 Mon Sep 17 00:00:00 2001
From: Dilip Kumar <dilip.kumar@enterprisedb.com>
Date: Thu, 7 Jul 2022 16:30:26 +0530
Subject: [PATCH v7 3/4] Assert checking (to be merged with 0002)

---
 src/backend/catalog/catalog.c    | 54 ++++++++++++++++++++++++++++++++++++++++
 src/backend/catalog/heap.c       |  5 ++++
 src/backend/catalog/storage.c    |  6 +++++
 src/backend/commands/tablecmds.c |  3 +++
 src/include/catalog/catalog.h    |  9 +++++++
 5 files changed, 77 insertions(+)

diff --git a/src/backend/catalog/catalog.c b/src/backend/catalog/catalog.c
index 155400c..9a22203 100644
--- a/src/backend/catalog/catalog.c
+++ b/src/backend/catalog/catalog.c
@@ -583,3 +583,57 @@ pg_stop_making_pinned_objects(PG_FUNCTION_ARGS)
 
 	PG_RETURN_VOID();
 }
+
+#ifdef USE_ASSERT_CHECKING
+
+/*
+ * Assert that there is no existing diskfile for input relnumber.
+ */
+void
+AssertRelfileNumberFileNotExists(Oid spcoid, RelFileNumber relnumber,
+								 char relpersistence)
+{
+	RelFileLocatorBackend rlocator;
+	char	   *rpath;
+	BackendId	backend;
+
+	/*
+	 * If we ever get here during pg_upgrade, there's something wrong; all
+	 * relfilenode assignments during a binary-upgrade run should be
+	 * determined by commands in the dump script.
+	 */
+	Assert(!IsBinaryUpgrade);
+
+	switch (relpersistence)
+	{
+		case RELPERSISTENCE_TEMP:
+			backend = BackendIdForTempRelations();
+			break;
+		case RELPERSISTENCE_UNLOGGED:
+		case RELPERSISTENCE_PERMANENT:
+			backend = InvalidBackendId;
+			break;
+		default:
+			elog(ERROR, "invalid relpersistence: %c", relpersistence);
+			return;	/* placate compiler */
+	}
+
+	/* this logic should match RelationInitPhysicalAddr */
+	rlocator.locator.spcOid = spcoid ? spcoid : MyDatabaseTableSpace;
+	rlocator.locator.dbOid =
+			(rlocator.locator.spcOid == GLOBALTABLESPACE_OID) ? InvalidOid :
+																MyDatabaseId;
+
+	/*
+	 * The relpath will vary based on the backend ID, so we must initialize
+	 * that properly here to make sure that any collisions based on filename
+	 * are properly detected.
+	 */
+	rlocator.backend = backend;
+
+	/* check for existing file of same name. */
+	rpath = relpath(rlocator, MAIN_FORKNUM);
+
+	Assert(access(rpath, F_OK) != 0);
+}
+#endif
\ No newline at end of file
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index 955ae3b..30fd15c 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -345,7 +345,12 @@ heap_create(const char *relname,
 		 * with oid same as relid.
 		 */
 		if (!RelFileNumberIsValid(relfilenumber))
+		{
 			relfilenumber = GetNewRelFileNumber();
+			AssertRelfileNumberFileNotExists(reltablespace,
+											 relfilenumber,
+											 relpersistence);
+		}
 	}
 
 	/*
diff --git a/src/backend/catalog/storage.c b/src/backend/catalog/storage.c
index d708af1..db85bd8 100644
--- a/src/backend/catalog/storage.c
+++ b/src/backend/catalog/storage.c
@@ -968,6 +968,9 @@ smgr_redo(XLogReaderState *record)
 		xl_smgr_create *xlrec = (xl_smgr_create *) XLogRecGetData(record);
 		SMgrRelation reln;
 
+		Assert(xlrec->rlocator.relNumber <=
+			   ShmemVariableCache->nextRelFileNumber);
+
 		reln = smgropen(xlrec->rlocator, InvalidBackendId);
 		smgrcreate(reln, xlrec->forkNum, true);
 	}
@@ -981,6 +984,9 @@ smgr_redo(XLogReaderState *record)
 		int			nforks = 0;
 		bool		need_fsm_vacuum = false;
 
+		Assert(xlrec->rlocator.relNumber <=
+			   ShmemVariableCache->nextRelFileNumber);
+
 		reln = smgropen(xlrec->rlocator, InvalidBackendId);
 
 		/*
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 3f48523..0678681 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -14377,6 +14377,9 @@ ATExecSetTableSpace(Oid tableOid, Oid newTableSpace, LOCKMODE lockmode)
 	 * will get the conflicting relfilenumber file.
 	 */
 	newrelfilenumber = GetNewRelFileNumber();
+	AssertRelfileNumberFileNotExists(newTableSpace,
+									 newrelfilenumber,
+									 rel->rd_rel->relpersistence);
 
 	/* Open old and new relation */
 	newrlocator = rel->rd_locator;
diff --git a/src/include/catalog/catalog.h b/src/include/catalog/catalog.h
index b452530..be6ba13 100644
--- a/src/include/catalog/catalog.h
+++ b/src/include/catalog/catalog.h
@@ -39,4 +39,13 @@ extern bool IsPinnedObject(Oid classId, Oid objectId);
 extern Oid	GetNewOidWithIndex(Relation relation, Oid indexId,
 							   AttrNumber oidcolumn);
 
+#ifdef USE_ASSERT_CHECKING
+extern void AssertRelfileNumberFileNotExists(Oid spcoid,
+											 RelFileNumber relnumber,
+											 char relpersistence);
+#else
+#define AssertRelfileNumberFileNotExists(spcoid, relnumber, relpersistence) \
+										((void)true)
+#endif
+
 #endif							/* CATALOG_H */
-- 
1.8.3.1