Revert 56-bit relfilenode change and follow-up commits.

There are still some alignment-related failures in the buildfarm,
which might or might not be able to be fixed quickly, but I've also
just realized that it increased the size of many WAL records by 4 bytes
because a block reference contains a RelFileLocator. The effect of that
hasn't been studied or discussed, so revert for now.

1 files changed, 9 insertions, 46 deletions

diff --git a/src/include/storage/buf_internals.h b/src/include/storage/buf_internals.h
index d4dc9eb3429..406db6be783 100644
--- a/src/include/storage/buf_internals.h
+++ b/src/include/storage/buf_internals.h
@@ -92,66 +92,29 @@ typedef struct buftag
 {
 	Oid			spcOid;			/* tablespace oid */
 	Oid			dbOid;			/* database oid */
-
-	/*
-	 * relForkDetails[] stores the fork number in the high 8 bits of the first
-	 * integer; the remaining 56 bits are used to store the relfilenmber.
-	 * Expanding the relfilenumber to a full 64 bits would require widening
-	 * the BufferTag, which is undesirable for performance reasons. We use
-	 * two 32-bit values here rather than a single 64-bit value to avoid
-	 * padding the struct out to a multiple of 8 bytes.
-	 */
-	uint32		relForkDetails[2];
+	RelFileNumber relNumber;	/* relation file number */
+	ForkNumber	forkNum;		/* fork number */
 	BlockNumber blockNum;		/* blknum relative to begin of reln */
 } BufferTag;
 
-/* High relNumber bits in relForkDetails[0] */
-#define	BUFTAG_RELNUM_HIGH_BITS	24
-
-/* Low relNumber bits in relForkDetails[1] */
-#define	BUFTAG_RELNUM_LOW_BITS	32
-
-/* Mask to fetch high bits of relNumber from relForkDetails[0] */
-#define	BUFTAG_RELNUM_HIGH_MASK	((1U << BUFTAG_RELNUM_HIGH_BITS) - 1)
-
-/* Mask to fetch low bits of relNumber from relForkDetails[1] */
-#define	BUFTAG_RELNUM_LOW_MASK	0XFFFFFFFF
-
 static inline RelFileNumber
 BufTagGetRelNumber(const BufferTag *tag)
 {
-	uint64		relnum;
-
-	relnum = ((uint64) tag->relForkDetails[0]) & BUFTAG_RELNUM_HIGH_MASK;
-	relnum = (relnum << BUFTAG_RELNUM_LOW_BITS) | tag->relForkDetails[1];
-
-	Assert(relnum <= MAX_RELFILENUMBER);
-	return (RelFileNumber) relnum;
+	return tag->relNumber;
 }
 
 static inline ForkNumber
 BufTagGetForkNum(const BufferTag *tag)
 {
-	ForkNumber		ret;
-
-	StaticAssertStmt(MAX_FORKNUM <= INT8_MAX,
-					 "MAX_FORKNUM can't be greater than INT8_MAX");
-
-	ret = (ForkNumber) (tag->relForkDetails[0] >> BUFTAG_RELNUM_HIGH_BITS);
-	return ret;
+	return tag->forkNum;
 }
 
 static inline void
 BufTagSetRelForkDetails(BufferTag *tag, RelFileNumber relnumber,
 						ForkNumber forknum)
 {
-	Assert(relnumber <= MAX_RELFILENUMBER);
-	Assert(forknum <= MAX_FORKNUM);
-
-	tag->relForkDetails[0] = (relnumber >> BUFTAG_RELNUM_LOW_BITS) &
-		BUFTAG_RELNUM_HIGH_MASK;
-	tag->relForkDetails[0] |= (forknum << BUFTAG_RELNUM_HIGH_BITS);
-	tag->relForkDetails[1] = relnumber & BUFTAG_RELNUM_LOW_MASK;
+	tag->relNumber = relnumber;
+	tag->forkNum = forknum;
 }
 
 static inline RelFileLocator
@@ -190,9 +153,9 @@ BufferTagsEqual(const BufferTag *tag1, const BufferTag *tag2)
 {
 	return (tag1->spcOid == tag2->spcOid) &&
 		(tag1->dbOid == tag2->dbOid) &&
-		(tag1->relForkDetails[0] == tag2->relForkDetails[0]) &&
-		(tag1->relForkDetails[1] == tag2->relForkDetails[1]) &&
-		(tag1->blockNum == tag2->blockNum);
+		(tag1->relNumber == tag2->relNumber) &&
+		(tag1->blockNum == tag2->blockNum) &&
+		(tag1->forkNum == tag2->forkNum);
 }
 
 static inline bool