ExtendBufferedWhat -> BufferManagerRelation.

Commit 31966b1 invented a way for functions dealing with relation
extension to accept a Relation in online code and an SMgrRelation in
recovery code.  It seems highly likely that future bufmgr.c interfaces
will face the same problem, and need to do something similar.
Generalize the names so that each interface doesn't have to re-invent
the wheel.

Back-patch to 16.  Since extension AM authors might start using the
constructor macros once 16 ships, we agreed to do the rename in 16
rather than waiting for 17.

Reviewed-by: Peter Geoghegan <pg@bowt.ie>
Reviewed-by: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/CA%2BhUKG%2B6tLD2BhpRWycEoti6LVLyQq457UL4ticP5xd8LqHySA%40mail.gmail.com

contrib/bloom/blutils.c

@@ -386,7 +386,7 @@ BloomNewBuffer(Relation index)
 	}
 
 	/* Must extend the file */
-	buffer = ExtendBufferedRel(EB_REL(index), MAIN_FORKNUM, NULL,
+	buffer = ExtendBufferedRel(BMR_REL(index), MAIN_FORKNUM, NULL,
 							   EB_LOCK_FIRST);
 
 	return buffer;

src/backend/access/brin/brin.c

@@ -848,7 +848,7 @@ brinbuild(Relation heap, Relation index, IndexInfo *indexInfo)
 	 * whole relation will be rolled back.
 	 */
 
-	meta = ExtendBufferedRel(EB_REL(index), MAIN_FORKNUM, NULL,
+	meta = ExtendBufferedRel(BMR_REL(index), MAIN_FORKNUM, NULL,
 							 EB_LOCK_FIRST | EB_SKIP_EXTENSION_LOCK);
 	Assert(BufferGetBlockNumber(meta) == BRIN_METAPAGE_BLKNO);
 
@@ -915,7 +915,7 @@ brinbuildempty(Relation index)
 	Buffer		metabuf;
 
 	/* An empty BRIN index has a metapage only. */
-	metabuf = ExtendBufferedRel(EB_REL(index), INIT_FORKNUM, NULL,
+	metabuf = ExtendBufferedRel(BMR_REL(index), INIT_FORKNUM, NULL,
 								EB_LOCK_FIRST | EB_SKIP_EXTENSION_LOCK);
 
 	/* Initialize and xlog metabuffer. */

src/backend/access/brin/brin_revmap.c

@@ -569,7 +569,7 @@ revmap_physical_extend(BrinRevmap *revmap)
 	}
 	else
 	{
-		buf = ExtendBufferedRel(EB_REL(irel), MAIN_FORKNUM, NULL,
+		buf = ExtendBufferedRel(BMR_REL(irel), MAIN_FORKNUM, NULL,
 								EB_LOCK_FIRST);
 		if (BufferGetBlockNumber(buf) != mapBlk)
 		{

src/backend/access/gin/gininsert.c

@@ -440,9 +440,9 @@ ginbuildempty(Relation index)
 				MetaBuffer;
 
 	/* An empty GIN index has two pages. */
-	MetaBuffer = ExtendBufferedRel(EB_REL(index), INIT_FORKNUM, NULL,
+	MetaBuffer = ExtendBufferedRel(BMR_REL(index), INIT_FORKNUM, NULL,
 								   EB_LOCK_FIRST | EB_SKIP_EXTENSION_LOCK);
-	RootBuffer = ExtendBufferedRel(EB_REL(index), INIT_FORKNUM, NULL,
+	RootBuffer = ExtendBufferedRel(BMR_REL(index), INIT_FORKNUM, NULL,
 								   EB_LOCK_FIRST | EB_SKIP_EXTENSION_LOCK);
 
 	/* Initialize and xlog metabuffer and root buffer. */

src/backend/access/gin/ginutil.c

@@ -327,7 +327,7 @@ GinNewBuffer(Relation index)
 	}
 
 	/* Must extend the file */
-	buffer = ExtendBufferedRel(EB_REL(index), MAIN_FORKNUM, NULL,
+	buffer = ExtendBufferedRel(BMR_REL(index), MAIN_FORKNUM, NULL,
 							   EB_LOCK_FIRST);
 
 	return buffer;

src/backend/access/gist/gist.c

@@ -134,7 +134,7 @@ gistbuildempty(Relation index)
 	Buffer		buffer;
 
 	/* Initialize the root page */
-	buffer = ExtendBufferedRel(EB_REL(index), INIT_FORKNUM, NULL,
+	buffer = ExtendBufferedRel(BMR_REL(index), INIT_FORKNUM, NULL,
 							   EB_SKIP_EXTENSION_LOCK | EB_LOCK_FIRST);
 
 	/* Initialize and xlog buffer */

src/backend/access/gist/gistutil.c

@@ -877,7 +877,7 @@ gistNewBuffer(Relation r, Relation heaprel)
 	}
 
 	/* Must extend the file */
-	buffer = ExtendBufferedRel(EB_REL(r), MAIN_FORKNUM, NULL,
+	buffer = ExtendBufferedRel(BMR_REL(r), MAIN_FORKNUM, NULL,
 							   EB_LOCK_FIRST);
 
 	return buffer;

src/backend/access/hash/hashpage.c

@@ -209,7 +209,7 @@ _hash_getnewbuf(Relation rel, BlockNumber blkno, ForkNumber forkNum)
 	/* smgr insists we explicitly extend the relation */
 	if (blkno == nblocks)
 	{
-		buf = ExtendBufferedRel(EB_REL(rel), forkNum, NULL,
+		buf = ExtendBufferedRel(BMR_REL(rel), forkNum, NULL,
 								EB_LOCK_FIRST | EB_SKIP_EXTENSION_LOCK);
 		if (BufferGetBlockNumber(buf) != blkno)
 			elog(ERROR, "unexpected hash relation size: %u, should be %u",

src/backend/access/heap/hio.c

@@ -339,7 +339,7 @@ RelationAddBlocks(Relation relation, BulkInsertState bistate,
 	 * [auto]vacuum trying to truncate later pages as REL_TRUNCATE_MINIMUM is
 	 * way larger.
 	 */
-	first_block = ExtendBufferedRelBy(EB_REL(relation), MAIN_FORKNUM,
+	first_block = ExtendBufferedRelBy(BMR_REL(relation), MAIN_FORKNUM,
 									  bistate ? bistate->strategy : NULL,
 									  EB_LOCK_FIRST,
 									  extend_by_pages,

src/backend/access/heap/visibilitymap.c

@@ -628,7 +628,7 @@ vm_extend(Relation rel, BlockNumber vm_nblocks)
 {
 	Buffer		buf;
 
-	buf = ExtendBufferedRelTo(EB_REL(rel), VISIBILITYMAP_FORKNUM, NULL,
+	buf = ExtendBufferedRelTo(BMR_REL(rel), VISIBILITYMAP_FORKNUM, NULL,
 							  EB_CREATE_FORK_IF_NEEDED |
 							  EB_CLEAR_SIZE_CACHE,
 							  vm_nblocks,

src/backend/access/nbtree/nbtpage.c

@@ -975,7 +975,7 @@ _bt_allocbuf(Relation rel, Relation heaprel)
 	 * otherwise would make, as we can't use _bt_lockbuf() without introducing
 	 * a race.
 	 */
-	buf = ExtendBufferedRel(EB_REL(rel), MAIN_FORKNUM, NULL, EB_LOCK_FIRST);
+	buf = ExtendBufferedRel(BMR_REL(rel), MAIN_FORKNUM, NULL, EB_LOCK_FIRST);
 	if (!RelationUsesLocalBuffers(rel))
 		VALGRIND_MAKE_MEM_DEFINED(BufferGetPage(buf), BLCKSZ);
 

src/backend/access/spgist/spgutils.c

@@ -405,7 +405,7 @@ SpGistNewBuffer(Relation index)
 		ReleaseBuffer(buffer);
 	}
 
-	buffer = ExtendBufferedRel(EB_REL(index), MAIN_FORKNUM, NULL,
+	buffer = ExtendBufferedRel(BMR_REL(index), MAIN_FORKNUM, NULL,
 							   EB_LOCK_FIRST);
 
 	return buffer;

src/backend/access/transam/xlogutils.c

@@ -524,7 +524,7 @@ XLogReadBufferExtended(RelFileLocator rlocator, ForkNumber forknum,
 		/* OK to extend the file */
 		/* we do this in recovery only - no rel-extension lock needed */
 		Assert(InRecovery);
-		buffer = ExtendBufferedRelTo(EB_SMGR(smgr, RELPERSISTENCE_PERMANENT),
+		buffer = ExtendBufferedRelTo(BMR_SMGR(smgr, RELPERSISTENCE_PERMANENT),
 									 forknum,
 									 NULL,
 									 EB_PERFORMING_RECOVERY |

src/backend/commands/sequence.c

@@ -377,7 +377,7 @@ fill_seq_fork_with_data(Relation rel, HeapTuple tuple, ForkNumber forkNum)
 
 	/* Initialize first page of relation with special magic number */
 
-	buf = ExtendBufferedRel(EB_REL(rel), forkNum, NULL,
+	buf = ExtendBufferedRel(BMR_REL(rel), forkNum, NULL,
 							EB_LOCK_FIRST | EB_SKIP_EXTENSION_LOCK);
 	Assert(BufferGetBlockNumber(buf) == 0);