Add a new option to RestoreBkpBlocks() to indicate if a cleanup lock should

be used instead of the normal exclusive lock, and make WAL redo functions
responsible for calling RestoreBkpBlocks(). They know better what kind of a
lock they need.

At the moment, this just moves things around with no functional change, but
makes the hot standby patch that's under review cleaner.

14 files changed, 92 insertions, 35 deletions

diff --git a/src/backend/access/gin/ginxlog.c b/src/backend/access/gin/ginxlog.c
index 04ae872d42a..362709de330 100644
--- a/src/backend/access/gin/ginxlog.c
+++ b/src/backend/access/gin/ginxlog.c
@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *			 $PostgreSQL: pgsql/src/backend/access/gin/ginxlog.c,v 1.16 2009/01/01 17:23:34 momjian Exp $
+ *			 $PostgreSQL: pgsql/src/backend/access/gin/ginxlog.c,v 1.17 2009/01/20 18:59:36 heikki Exp $
  *-------------------------------------------------------------------------
  */
 #include "postgres.h"
@@ -438,6 +438,8 @@ gin_redo(XLogRecPtr lsn, XLogRecord *record)
 {
 	uint8		info = record->xl_info & ~XLR_INFO_MASK;
 
+	RestoreBkpBlocks(lsn, record, false);
+
 	topCtx = MemoryContextSwitchTo(opCtx);
 	switch (info)
 	{
diff --git a/src/backend/access/gist/gistxlog.c b/src/backend/access/gist/gistxlog.c
index b6d76a1f477..672d714e014 100644
--- a/src/backend/access/gist/gistxlog.c
+++ b/src/backend/access/gist/gistxlog.c
@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *			 $PostgreSQL: pgsql/src/backend/access/gist/gistxlog.c,v 1.31 2009/01/01 17:23:35 momjian Exp $
+ *			 $PostgreSQL: pgsql/src/backend/access/gist/gistxlog.c,v 1.32 2009/01/20 18:59:36 heikki Exp $
  *-------------------------------------------------------------------------
  */
 #include "postgres.h"
@@ -394,9 +394,10 @@ void
 gist_redo(XLogRecPtr lsn, XLogRecord *record)
 {
 	uint8		info = record->xl_info & ~XLR_INFO_MASK;
-
 	MemoryContext oldCxt;
 
+	RestoreBkpBlocks(lsn, record, false);
+
 	oldCxt = MemoryContextSwitchTo(opCtx);
 	switch (info)
 	{
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index c9d655de577..43af0c7e048 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/access/heap/heapam.c,v 1.273 2009/01/01 17:23:35 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/access/heap/heapam.c,v 1.274 2009/01/20 18:59:36 heikki Exp $
  *
  *
  * INTERFACE ROUTINES
@@ -4777,6 +4777,8 @@ heap_redo(XLogRecPtr lsn, XLogRecord *record)
 {
 	uint8		info = record->xl_info & ~XLR_INFO_MASK;
 
+	RestoreBkpBlocks(lsn, record, false);
+
 	switch (info & XLOG_HEAP_OPMASK)
 	{
 		case XLOG_HEAP_INSERT:
@@ -4816,12 +4818,15 @@ heap2_redo(XLogRecPtr lsn, XLogRecord *record)
 	switch (info & XLOG_HEAP_OPMASK)
 	{
 		case XLOG_HEAP2_FREEZE:
+			RestoreBkpBlocks(lsn, record, false);
 			heap_xlog_freeze(lsn, record);
 			break;
 		case XLOG_HEAP2_CLEAN:
+			RestoreBkpBlocks(lsn, record, true);
 			heap_xlog_clean(lsn, record, false);
 			break;
 		case XLOG_HEAP2_CLEAN_MOVE:
+			RestoreBkpBlocks(lsn, record, true);
 			heap_xlog_clean(lsn, record, true);
 			break;
 		default:
diff --git a/src/backend/access/nbtree/nbtxlog.c b/src/backend/access/nbtree/nbtxlog.c
index c72dda2806a..3de7d50e012 100644
--- a/src/backend/access/nbtree/nbtxlog.c
+++ b/src/backend/access/nbtree/nbtxlog.c
@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/access/nbtree/nbtxlog.c,v 1.53 2009/01/01 17:23:36 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/access/nbtree/nbtxlog.c,v 1.54 2009/01/20 18:59:37 heikki Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -714,6 +714,8 @@ btree_redo(XLogRecPtr lsn, XLogRecord *record)
 {
 	uint8		info = record->xl_info & ~XLR_INFO_MASK;
 
+	RestoreBkpBlocks(lsn, record, false);
+
 	switch (info)
 	{
 		case XLOG_BTREE_INSERT_LEAF:
diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index e9c422b85ef..368d2c9d1a5 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -26,7 +26,7 @@
  * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/backend/access/transam/clog.c,v 1.51 2009/01/01 17:23:36 momjian Exp $
+ * $PostgreSQL: pgsql/src/backend/access/transam/clog.c,v 1.52 2009/01/20 18:59:37 heikki Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -684,6 +684,9 @@ clog_redo(XLogRecPtr lsn, XLogRecord *record)
 {
 	uint8		info = record->xl_info & ~XLR_INFO_MASK;
 
+	/* Backup blocks are not used in clog records */
+	Assert(!(record->xl_info & XLR_BKP_BLOCK_MASK));
+
 	if (info == CLOG_ZEROPAGE)
 	{
 		int			pageno;
diff --git a/src/backend/access/transam/multixact.c b/src/backend/access/transam/multixact.c
index a0ab280a1b0..4888b0b36b9 100644
--- a/src/backend/access/transam/multixact.c
+++ b/src/backend/access/transam/multixact.c
@@ -42,7 +42,7 @@
  * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/backend/access/transam/multixact.c,v 1.29 2009/01/01 17:23:36 momjian Exp $
+ * $PostgreSQL: pgsql/src/backend/access/transam/multixact.c,v 1.30 2009/01/20 18:59:37 heikki Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1870,6 +1870,9 @@ multixact_redo(XLogRecPtr lsn, XLogRecord *record)
 {
 	uint8		info = record->xl_info & ~XLR_INFO_MASK;
 
+	/* Backup blocks are not used in multixact records */
+	Assert(!(record->xl_info & XLR_BKP_BLOCK_MASK));
+
 	if (info == XLOG_MULTIXACT_ZERO_OFF_PAGE)
 	{
 		int			pageno;
diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c
index 42f6bb8125b..fbe55135473 100644
--- a/src/backend/access/transam/xact.c
+++ b/src/backend/access/transam/xact.c
@@ -10,7 +10,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/access/transam/xact.c,v 1.271 2009/01/01 17:23:36 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/access/transam/xact.c,v 1.272 2009/01/20 18:59:37 heikki Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -4308,6 +4308,9 @@ xact_redo(XLogRecPtr lsn, XLogRecord *record)
 {
 	uint8		info = record->xl_info & ~XLR_INFO_MASK;
 
+	/* Backup blocks are not used in xact records */
+	Assert(!(record->xl_info & XLR_BKP_BLOCK_MASK));
+
 	if (info == XLOG_XACT_COMMIT)
 	{
 		xl_xact_commit *xlrec = (xl_xact_commit *) XLogRecGetData(record);
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 9a2b3308b1e..bf85d2ffae7 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/backend/access/transam/xlog.c,v 1.327 2009/01/11 18:02:17 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/access/transam/xlog.c,v 1.328 2009/01/20 18:59:37 heikki Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -2922,9 +2922,15 @@ CleanupBackupHistory(void)
  * page might not be.  This will force us to replay all subsequent
  * modifications of the page that appear in XLOG, rather than possibly
  * ignoring them as already applied, but that's not a huge drawback.
+ *
+ * If 'cleanup' is true, a cleanup lock is used when restoring blocks.
+ * Otherwise, a normal exclusive lock is used.  At the moment, that's just
+ * pro forma, because there can't be any regular backends in the system
+ * during recovery.  The 'cleanup' argument applies to all backup blocks
+ * in the WAL record, that suffices for now.
  */
-static void
-RestoreBkpBlocks(XLogRecord *record, XLogRecPtr lsn)
+void
+RestoreBkpBlocks(XLogRecPtr lsn, XLogRecord *record, bool cleanup)
 {
 	Buffer		buffer;
 	Page		page;
@@ -2944,6 +2950,11 @@ RestoreBkpBlocks(XLogRecord *record, XLogRecPtr lsn)
 		buffer = XLogReadBufferExtended(bkpb.node, bkpb.fork, bkpb.block,
 										RBM_ZERO);
 		Assert(BufferIsValid(buffer));
+		if (cleanup)
+			LockBufferForCleanup(buffer);
+		else
+			LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
+
 		page = (Page) BufferGetPage(buffer);
 
 		if (bkpb.hole_length == 0)
@@ -5199,9 +5210,6 @@ StartupXLOG(void)
 					TransactionIdAdvance(ShmemVariableCache->nextXid);
 				}
 
-				if (record->xl_info & XLR_BKP_BLOCK_MASK)
-					RestoreBkpBlocks(record, EndRecPtr);
-
 				RmgrTable[record->xl_rmid].rm_redo(EndRecPtr, record);
 
 				/* Pop the error context stack */
@@ -6233,6 +6241,9 @@ xlog_redo(XLogRecPtr lsn, XLogRecord *record)
 {
 	uint8		info = record->xl_info & ~XLR_INFO_MASK;
 
+	/* Backup blocks are not used in xlog records */
+	Assert(!(record->xl_info & XLR_BKP_BLOCK_MASK));
+
 	if (info == XLOG_NEXTOID)
 	{
 		Oid			nextOid;
diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c
index 02b281c86ad..458af10ca19 100644
--- a/src/backend/access/transam/xlogutils.c
+++ b/src/backend/access/transam/xlogutils.c
@@ -11,7 +11,7 @@
  * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/backend/access/transam/xlogutils.c,v 1.66 2009/01/01 17:23:36 momjian Exp $
+ * $PostgreSQL: pgsql/src/backend/access/transam/xlogutils.c,v 1.67 2009/01/20 18:59:37 heikki Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -217,8 +217,19 @@ XLogCheckInvalidPages(void)
 
 /*
  * XLogReadBuffer
- *		A shorthand of XLogReadBufferExtended(), for reading from the main
- *		fork.
+ *		Read a page during XLOG replay.
+ *
+ * This is a shorthand of XLogReadBufferExtended() followed by
+ * LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE), for reading from the main
+ * fork.
+ *
+ * (Getting the lock is not really necessary, since we expect that this is
+ * only used during single-process XLOG replay, but some subroutines such
+ * as MarkBufferDirty will complain if we don't. And hopefully we'll get
+ * hot standby support in the future, where there will be backends running
+ * read-only queries during XLOG replay.)
+ *
+ * The returned buffer is exclusively-locked.
  *
  * For historical reasons, instead of a ReadBufferMode argument, this only
  * supports RBM_ZERO (init == true) and RBM_NORMAL (init == false) modes.
@@ -226,22 +237,21 @@ XLogCheckInvalidPages(void)
 Buffer
 XLogReadBuffer(RelFileNode rnode, BlockNumber blkno, bool init)
 {
-	return XLogReadBufferExtended(rnode, MAIN_FORKNUM, blkno,
-								  init ? RBM_ZERO : RBM_NORMAL);
+	Buffer buf;
+	buf = XLogReadBufferExtended(rnode, MAIN_FORKNUM, blkno,
+								 init ? RBM_ZERO : RBM_NORMAL);
+	if (BufferIsValid(buf))
+		LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
+
+	return buf;
 }
 
 /*
  * XLogReadBufferExtended
  *		Read a page during XLOG replay
  *
- * This is functionally comparable to ReadBuffer followed by
- * LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE): you get back a pinned
- * and locked buffer.  (Getting the lock is not really necessary, since we
- * expect that this is only used during single-process XLOG replay, but
- * some subroutines such as MarkBufferDirty will complain if we don't.)
- *
- * There's some differences in the behavior wrt. the "mode" argument,
- * compared to ReadBufferExtended:
+ * This is functionally comparable to ReadBufferExtended. There's some
+ * differences in the behavior wrt. the "mode" argument:
  *
  * In RBM_NORMAL mode, if the page doesn't exist, or contains all-zeroes, we
  * return InvalidBuffer. In this case the caller should silently skip the
@@ -306,16 +316,19 @@ XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum,
 		Assert(BufferGetBlockNumber(buffer) == blkno);
 	}
 
-	LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
-
 	if (mode == RBM_NORMAL)
 	{
 		/* check that page has been initialized */
 		Page		page = (Page) BufferGetPage(buffer);
 
+		/*
+		 * We assume that PageIsNew is safe without a lock. During recovery,
+		 * there should be no other backends that could modify the buffer at
+		 * the same time.
+		 */
 		if (PageIsNew(page))
 		{
-			UnlockReleaseBuffer(buffer);
+			ReleaseBuffer(buffer);
 			log_invalid_page(rnode, forknum, blkno, true);
 			return InvalidBuffer;
 		}
diff --git a/src/backend/catalog/storage.c b/src/backend/catalog/storage.c
index aec9d05852e..e1a0f6254c6 100644
--- a/src/backend/catalog/storage.c
+++ b/src/backend/catalog/storage.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/catalog/storage.c,v 1.4 2009/01/04 14:59:22 heikki Exp $
+ *	  $PostgreSQL: pgsql/src/backend/catalog/storage.c,v 1.5 2009/01/20 18:59:37 heikki Exp $
  *
  * NOTES
  *	  Some of this code used to be in storage/smgr/smgr.c, and the
@@ -401,6 +401,9 @@ smgr_redo(XLogRecPtr lsn, XLogRecord *record)
 {
 	uint8		info = record->xl_info & ~XLR_INFO_MASK;
 
+	/* Backup blocks are not used in smgr records */
+	Assert(!(record->xl_info & XLR_BKP_BLOCK_MASK));
+
 	if (info == XLOG_SMGR_CREATE)
 	{
 		xl_smgr_create *xlrec = (xl_smgr_create *) XLogRecGetData(record);
diff --git a/src/backend/commands/dbcommands.c b/src/backend/commands/dbcommands.c
index e9e8ea3363d..2ff7021f285 100644
--- a/src/backend/commands/dbcommands.c
+++ b/src/backend/commands/dbcommands.c
@@ -13,7 +13,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/dbcommands.c,v 1.217 2009/01/01 17:23:37 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/dbcommands.c,v 1.218 2009/01/20 18:59:37 heikki Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1941,6 +1941,9 @@ dbase_redo(XLogRecPtr lsn, XLogRecord *record)
 {
 	uint8		info = record->xl_info & ~XLR_INFO_MASK;
 
+	/* Backup blocks are not used in dbase records */
+	Assert(!(record->xl_info & XLR_BKP_BLOCK_MASK));
+
 	if (info == XLOG_DBASE_CREATE)
 	{
 		xl_dbase_create_rec *xlrec = (xl_dbase_create_rec *) XLogRecGetData(record);
diff --git a/src/backend/commands/sequence.c b/src/backend/commands/sequence.c
index c8f513d2da7..d68f525ba02 100644
--- a/src/backend/commands/sequence.c
+++ b/src/backend/commands/sequence.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/sequence.c,v 1.156 2009/01/01 17:23:39 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/sequence.c,v 1.157 2009/01/20 18:59:37 heikki Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1339,6 +1339,9 @@ seq_redo(XLogRecPtr lsn, XLogRecord *record)
 	xl_seq_rec *xlrec = (xl_seq_rec *) XLogRecGetData(record);
 	sequence_magic *sm;
 
+	/* Backup blocks are not used in seq records */
+	Assert(!(record->xl_info & XLR_BKP_BLOCK_MASK));
+
 	if (info != XLOG_SEQ_LOG)
 		elog(PANIC, "seq_redo: unknown op code %u", info);
 
diff --git a/src/backend/commands/tablespace.c b/src/backend/commands/tablespace.c
index 610d69358b6..54818ff34d7 100644
--- a/src/backend/commands/tablespace.c
+++ b/src/backend/commands/tablespace.c
@@ -37,7 +37,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/tablespace.c,v 1.59 2009/01/01 17:23:40 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/tablespace.c,v 1.60 2009/01/20 18:59:37 heikki Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1276,6 +1276,9 @@ tblspc_redo(XLogRecPtr lsn, XLogRecord *record)
 {
 	uint8		info = record->xl_info & ~XLR_INFO_MASK;
 
+	/* Backup blocks are not used in tblspc records */
+	Assert(!(record->xl_info & XLR_BKP_BLOCK_MASK));
+
 	if (info == XLOG_TBLSPC_CREATE)
 	{
 		xl_tblspc_create_rec *xlrec = (xl_tblspc_create_rec *) XLogRecGetData(record);
diff --git a/src/backend/storage/freespace/freespace.c b/src/backend/storage/freespace/freespace.c
index d8a1bd3a62b..558c56f80d5 100644
--- a/src/backend/storage/freespace/freespace.c
+++ b/src/backend/storage/freespace/freespace.c
@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/storage/freespace/freespace.c,v 1.71 2009/01/01 17:23:47 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/storage/freespace/freespace.c,v 1.72 2009/01/20 18:59:37 heikki Exp $
  *
  *
  * NOTES:
@@ -212,6 +212,8 @@ XLogRecordPageWithFreeSpace(RelFileNode rnode, BlockNumber heapBlk,
 
 	/* If the page doesn't exist already, extend */
 	buf = XLogReadBufferExtended(rnode, FSM_FORKNUM, blkno, RBM_ZERO_ON_ERROR);
+	LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
+
 	page = BufferGetPage(buf);
 	if (PageIsNew(page))
 		PageInit(page, BLCKSZ, 0);