PoC: PG-1392 Encrypt all relation forks

It is unclear to me why we stopped encrypting the FSM and visibility
map forks in commit e514ac5 which
sadly does not explain why we stopped doing so. Both of them leak
metadata that we do not have to. Especially once we also encrypt the
catalogs.

Author: jeltz

contrib/pg_tde/src/smgr/pg_tde_smgr.c

@@ -26,15 +26,6 @@ typedef struct TDESMgrRelationData
 
 typedef TDESMgrRelationData *TDESMgrRelation;
 
-/*
- * we only encrypt main and init forks
- */
-static inline bool
-tde_is_encryption_required(TDESMgrRelation tdereln, ForkNumber forknum)
-{
-	return (tdereln->encrypted_relation && (forknum == MAIN_FORKNUM || forknum == INIT_FORKNUM));
-}
-
 static InternalKey *
 tde_smgr_get_key(SMgrRelation reln, RelFileLocator *old_locator, bool can_create)
 {
@@ -90,7 +81,7 @@ tde_mdwritev(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
 	TDESMgrRelation tdereln = (TDESMgrRelation) reln;
 	InternalKey *int_key = &tdereln->relKey;
 
-	if (!tde_is_encryption_required(tdereln, forknum))
+	if (!tdereln->encrypted_relation)
 	{
 		mdwritev(reln, forknum, blocknum, buffers, nblocks, skipFsync);
 	}
@@ -131,7 +122,7 @@ tde_mdextend(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
 	TDESMgrRelation tdereln = (TDESMgrRelation) reln;
 	InternalKey *int_key = &tdereln->relKey;
 
-	if (!tde_is_encryption_required(tdereln, forknum))
+	if (!tdereln->encrypted_relation)
 	{
 		mdextend(reln, forknum, blocknum, buffer, skipFsync);
 	}
@@ -165,7 +156,7 @@ tde_mdreadv(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
 
 	mdreadv(reln, forknum, blocknum, buffers, nblocks);
 
-	if (!tde_is_encryption_required(tdereln, forknum))
+	if (!tdereln->encrypted_relation)
 		return;
 
 	AesInit();