From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Fri, 12 Jan 2001 21:54:01 +0000 (+0000)
Subject: Add more critical-section calls: all code sections that hold spinlocks
X-Git-Tag: REL7_1~847
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=6162432de9fb023b710c171f196e27b910e45fa7;p=postgresql

Add more critical-section calls: all code sections that hold spinlocks
are now critical sections, so as to ensure die() won't interrupt us while
we are munging shared-memory data structures.  Avoid insecure intermediate
states in some code that proc_exit will call, like palloc/pfree.  Rename
START/END_CRIT_CODE to START/END_CRIT_SECTION, since that seems to be
what people tend to call them anyway, and make them be called with () like
a function call, in hopes of not confusing pg_indent.
I doubt that this is sufficient to make SIGTERM safe anywhere; there's
just too much code that could get invoked during proc_exit().
---

diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index 612e4c6861..db443218b4 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/access/heap/heapam.c,v 1.106 2001/01/07 22:14:31 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/access/heap/heapam.c,v 1.107 2001/01/12 21:53:54 tgl Exp $
  *
  *
  * INTERFACE ROUTINES
@@ -1359,7 +1359,7 @@ heap_insert(Relation relation, HeapTuple tup)
 	buffer = RelationGetBufferForTuple(relation, tup->t_len);
 
 	/* NO ELOG(ERROR) from here till changes are logged */
-	START_CRIT_CODE;
+	START_CRIT_SECTION();
 	RelationPutHeapTuple(relation, buffer, tup);
 
 	/* XLOG stuff */
@@ -1405,7 +1405,7 @@ heap_insert(Relation relation, HeapTuple tup)
 		PageSetLSN(page, recptr);
 		PageSetSUI(page, ThisStartUpID);
 	}
-	END_CRIT_CODE;
+	END_CRIT_SECTION();
 
 	LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
 	WriteBuffer(buffer);
@@ -1503,7 +1503,7 @@ l1:
 		return result;
 	}
 
-	START_CRIT_CODE;
+	START_CRIT_SECTION();
 	/* store transaction information of xact deleting the tuple */
 	TransactionIdStore(GetCurrentTransactionId(), &(tp.t_data->t_xmax));
 	tp.t_data->t_cmax = GetCurrentCommandId();
@@ -1532,7 +1532,7 @@ l1:
 		PageSetLSN(dp, recptr);
 		PageSetSUI(dp, ThisStartUpID);
 	}
-	END_CRIT_CODE;
+	END_CRIT_SECTION();
 
 #ifdef TUPLE_TOASTER_ACTIVE
 	/* ----------
@@ -1702,7 +1702,7 @@ l2:
 	}
 
 	/* NO ELOG(ERROR) from here till changes are logged */
-	START_CRIT_CODE;
+	START_CRIT_SECTION();
 
 	RelationPutHeapTuple(relation, newbuf, newtup);	/* insert new tuple */
 	if (buffer == newbuf)
@@ -1734,7 +1734,7 @@ l2:
 		PageSetLSN(BufferGetPage(buffer), recptr);
 		PageSetSUI(BufferGetPage(buffer), ThisStartUpID);
 	}
-	END_CRIT_CODE;
+	END_CRIT_SECTION();
 
 	if (newbuf != buffer)
 		LockBuffer(newbuf, BUFFER_LOCK_UNLOCK);
diff --git a/src/backend/access/nbtree/nbtinsert.c b/src/backend/access/nbtree/nbtinsert.c
index cdd5c6d620..1aae86c002 100644
--- a/src/backend/access/nbtree/nbtinsert.c
+++ b/src/backend/access/nbtree/nbtinsert.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/access/nbtree/nbtinsert.c,v 1.72 2000/12/29 20:47:16 vadim Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/access/nbtree/nbtinsert.c,v 1.73 2001/01/12 21:53:55 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -518,7 +518,7 @@ _bt_insertonpg(Relation rel,
 	}
 	else
 	{
-		START_CRIT_CODE;
+		START_CRIT_SECTION();
 		_bt_pgaddtup(rel, page, itemsz, btitem, newitemoff, "page");
 		itup_off = newitemoff;
 		itup_blkno = BufferGetBlockNumber(buf);
@@ -563,7 +563,7 @@ _bt_insertonpg(Relation rel,
 			PageSetSUI(page, ThisStartUpID);
 		}
 
-		END_CRIT_CODE;
+		END_CRIT_SECTION();
 		/* Write out the updated page and release pin/lock */
 		_bt_wrtbuf(rel, buf);
 	}
@@ -774,7 +774,7 @@ _bt_split(Relation rel, Buffer buf, OffsetNumber firstright,
 	 * NO ELOG(ERROR) till right sibling is updated.
 	 *
 	 */
-	START_CRIT_CODE;
+	START_CRIT_SECTION();
 	{
 		xl_btree_split	xlrec;
 		int				flag = (newitemonleft) ? 
@@ -863,7 +863,7 @@ _bt_split(Relation rel, Buffer buf, OffsetNumber firstright,
 	/* write and release the old right sibling */
 	if (!P_RIGHTMOST(ropaque))
 		_bt_wrtbuf(rel, sbuf);
-	END_CRIT_CODE;
+	END_CRIT_SECTION();
 
 	/* split's done */
 	return rbuf;
@@ -1160,7 +1160,7 @@ _bt_newroot(Relation rel, Buffer lbuf, Buffer rbuf)
 	metad = BTPageGetMeta(metapg);
 
 	/* NO ELOG(ERROR) from here till newroot op is logged */
-	START_CRIT_CODE;
+	START_CRIT_SECTION();
 
 	/* set btree special data */
 	rootopaque = (BTPageOpaque) PageGetSpecialPointer(rootpage);
@@ -1253,7 +1253,7 @@ _bt_newroot(Relation rel, Buffer lbuf, Buffer rbuf)
 		PageSetSUI(metapg, ThisStartUpID);
 
 	}
-	END_CRIT_CODE;
+	END_CRIT_SECTION();
 
 	/* write and let go of the new root buffer */
 	_bt_wrtbuf(rel, rootbuf);
diff --git a/src/backend/access/nbtree/nbtpage.c b/src/backend/access/nbtree/nbtpage.c
index e2e403a2af..81faf71c9d 100644
--- a/src/backend/access/nbtree/nbtpage.c
+++ b/src/backend/access/nbtree/nbtpage.c
@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/access/nbtree/nbtpage.c,v 1.45 2000/12/29 20:47:17 vadim Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/access/nbtree/nbtpage.c,v 1.46 2001/01/12 21:53:55 tgl Exp $
  *
  *	NOTES
  *	   Postgres btree pages look like ordinary relation pages.	The opaque
@@ -165,7 +165,7 @@ _bt_getroot(Relation rel, int access)
 			rootpage = BufferGetPage(rootbuf);
 
 			/* NO ELOG(ERROR) till meta is updated */
-			START_CRIT_CODE;
+			START_CRIT_SECTION();
 
 			metad->btm_root = rootblkno;
 			metad->btm_level = 1;
@@ -197,7 +197,7 @@ _bt_getroot(Relation rel, int access)
 				PageSetSUI(metapg, ThisStartUpID);
 			}
 
-			END_CRIT_CODE;
+			END_CRIT_SECTION();
 
 			_bt_wrtnorelbuf(rel, rootbuf);
 
@@ -410,7 +410,7 @@ _bt_pagedel(Relation rel, ItemPointer tid)
 	buf = _bt_getbuf(rel, blkno, BT_WRITE);
 	page = BufferGetPage(buf);
 
-	START_CRIT_CODE;
+	START_CRIT_SECTION();
 	PageIndexTupleDelete(page, offno);
 	/* XLOG stuff */
 	{
@@ -435,7 +435,7 @@ _bt_pagedel(Relation rel, ItemPointer tid)
 		PageSetLSN(page, recptr);
 		PageSetSUI(page, ThisStartUpID);
 	}
-	END_CRIT_CODE;
+	END_CRIT_SECTION();
 
 	/* write the buffer and release the lock */
 	_bt_wrtbuf(rel, buf);
diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c
index 50f4f1a100..e3f4a5618f 100644
--- a/src/backend/access/transam/xact.c
+++ b/src/backend/access/transam/xact.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/access/transam/xact.c,v 1.91 2000/12/28 13:00:08 vadim Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/access/transam/xact.c,v 1.92 2001/01/12 21:53:56 tgl Exp $
  *
  * NOTES
  *		Transaction aborts can now occur two ways:
@@ -678,7 +678,7 @@ RecordTransactionCommit()
 		rdata.len = SizeOfXactCommit;
 		rdata.next = NULL;
 
-		START_CRIT_CODE;
+		START_CRIT_SECTION();
 		/*
 		 * SHOULD SAVE ARRAY OF RELFILENODE-s TO DROP
 		 */
@@ -697,7 +697,7 @@ RecordTransactionCommit()
 		TransactionIdCommit(xid);
 
 		MyProc->logRec.xrecoff = 0;
-		END_CRIT_CODE;
+		END_CRIT_SECTION();
 	}
 
 	if (leak)
@@ -800,12 +800,12 @@ RecordTransactionAbort(void)
 		rdata.len = SizeOfXactAbort;
 		rdata.next = NULL;
 
-		START_CRIT_CODE;
+		START_CRIT_SECTION();
 		recptr = XLogInsert(RM_XACT_ID, XLOG_XACT_ABORT, &rdata);
 
 		TransactionIdAbort(xid);
 		MyProc->logRec.xrecoff = 0;
-		END_CRIT_CODE;
+		END_CRIT_SECTION();
 	}
 
 	/*
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index c0b6104db5..e995b06f91 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -6,7 +6,7 @@
  * Portions Copyright (c) 1996-2000, PostgreSQL, Inc
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Header: /cvsroot/pgsql/src/backend/access/transam/xlog.c,v 1.48 2001/01/09 06:24:32 vadim Exp $
+ * $Header: /cvsroot/pgsql/src/backend/access/transam/xlog.c,v 1.49 2001/01/12 21:53:56 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -42,7 +42,7 @@
 int			XLOGbuffers = 8;
 int			XLOGfiles = 0;	/* how many files to pre-allocate */
 XLogRecPtr	MyLastRecPtr = {0, 0};
-uint32		CritSectionCount = 0;
+volatile uint32 CritSectionCount = 0;
 bool		InRecovery = false;
 StartUpID	ThisStartUpID = 0;
 XLogRecPtr	RedoRecPtr;
@@ -382,7 +382,7 @@ begin:;
 	if (len == 0 || len > MAXLOGRECSZ)
 		elog(STOP, "XLogInsert: invalid record len %u", len);
 
-	START_CRIT_CODE;
+	START_CRIT_SECTION();
 
 	/* obtain xlog insert lock */
 	if (TAS(&(XLogCtl->insert_lck)))	/* busy */
@@ -447,7 +447,7 @@ begin:;
 	if (repeat)
 	{
 		S_UNLOCK(&(XLogCtl->insert_lck));
-		END_CRIT_CODE;
+		END_CRIT_SECTION();
 		goto begin;
 	}
 
@@ -618,7 +618,7 @@ begin:;
 		S_UNLOCK(&(XLogCtl->info_lck));
 	}
 
-	END_CRIT_CODE;
+	END_CRIT_SECTION();
 	return (RecPtr);
 }
 
@@ -647,7 +647,7 @@ XLogFlush(XLogRecPtr record)
 	if (XLByteLE(record, LgwrResult.Flush))
 		return;
 
-	START_CRIT_CODE;
+	START_CRIT_SECTION();
 
 	WriteRqst = LgwrRqst.Write;
 	for (;;)
@@ -659,7 +659,7 @@ XLogFlush(XLogRecPtr record)
 			if (XLByteLE(record, LgwrResult.Flush))
 			{
 				S_UNLOCK(&(XLogCtl->info_lck));
-				END_CRIT_CODE;
+				END_CRIT_SECTION();
 				return;
 			}
 			if (XLByteLT(XLogCtl->LgwrRqst.Flush, record))
@@ -705,7 +705,7 @@ XLogFlush(XLogRecPtr record)
 				if (XLByteLE(record, LgwrResult.Flush))
 				{
 					S_UNLOCK(&(XLogCtl->lgwr_lck));
-					END_CRIT_CODE;
+					END_CRIT_SECTION();
 					return;
 				}
 				if (XLByteLT(LgwrResult.Write, WriteRqst))
@@ -715,7 +715,7 @@ XLogFlush(XLogRecPtr record)
 					S_UNLOCK(&(XLogCtl->lgwr_lck));
 					if (XLByteLT(LgwrResult.Flush, record))
 						elog(STOP, "XLogFlush: request is not satisfied");
-					END_CRIT_CODE;
+					END_CRIT_SECTION();
 					return;
 				}
 				break;
@@ -756,7 +756,7 @@ XLogFlush(XLogRecPtr record)
 
 	S_UNLOCK(&(XLogCtl->lgwr_lck));
 
-	END_CRIT_CODE;
+	END_CRIT_SECTION();
 	return;
 
 }
@@ -2081,7 +2081,7 @@ CreateCheckPoint(bool shutdown)
 	if (MyLastRecPtr.xrecoff != 0)
 		elog(ERROR, "CreateCheckPoint: cannot be called inside transaction block");
  
-	START_CRIT_CODE;
+	START_CRIT_SECTION();
 
 	/* Grab lock, using larger than normal sleep between tries (1 sec) */
 	while (TAS(&(XLogCtl->chkp_lck)))
@@ -2230,7 +2230,7 @@ CreateCheckPoint(bool shutdown)
 	S_UNLOCK(&(XLogCtl->chkp_lck));
 
 	MyLastRecPtr.xrecoff = 0;	/* to avoid commit record */
-	END_CRIT_CODE;
+	END_CRIT_SECTION();
 
 	return;
 }
diff --git a/src/backend/commands/sequence.c b/src/backend/commands/sequence.c
index 64fc0102a8..f6e6328312 100644
--- a/src/backend/commands/sequence.c
+++ b/src/backend/commands/sequence.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/commands/sequence.c,v 1.47 2000/12/28 13:00:17 vadim Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/commands/sequence.c,v 1.48 2001/01/12 21:53:56 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -301,7 +301,7 @@ nextval(PG_FUNCTION_ARGS)
 	elm->last = result;			/* last returned number */
 	elm->cached = last;			/* last fetched number */
 
-	START_CRIT_CODE;
+	START_CRIT_SECTION();
 	if (logit)
 	{
 		xl_seq_rec	xlrec;
@@ -338,7 +338,7 @@ nextval(PG_FUNCTION_ARGS)
 	seq->is_called = 't';
 	Assert(log >= 0);
 	seq->log_cnt = log;			/* how much is logged */
-	END_CRIT_CODE;
+	END_CRIT_SECTION();
 
 	LockBuffer(buf, BUFFER_LOCK_UNLOCK);
 
@@ -398,7 +398,7 @@ do_setval(char *seqname, int32 next, bool iscalled)
 	elm->last = next;			/* last returned number */
 	elm->cached = next;			/* last cached number (forget cached values) */
 
-	START_CRIT_CODE;
+	START_CRIT_SECTION();
 	{
 		xl_seq_rec	xlrec;
 		XLogRecPtr	recptr;
@@ -429,7 +429,7 @@ do_setval(char *seqname, int32 next, bool iscalled)
 	seq->last_value = next;		/* last fetched number */
 	seq->is_called = iscalled ? 't' : 'f';
 	seq->log_cnt = (iscalled) ? 0 : 1;
-	END_CRIT_CODE;
+	END_CRIT_SECTION();
 
 	LockBuffer(buf, BUFFER_LOCK_UNLOCK);
 
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index 738d9e7283..76425652b9 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/commands/vacuum.c,v 1.181 2000/12/30 15:19:55 vadim Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/commands/vacuum.c,v 1.182 2001/01/12 21:53:56 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1427,7 +1427,7 @@ repair_frag(VRelStats *vacrelstats, Relation onerel,
 					Cpage = BufferGetPage(Cbuf);
 
 					/* NO ELOG(ERROR) TILL CHANGES ARE LOGGED */
-					START_CRIT_CODE;
+					START_CRIT_SECTION();
 
 					Citemid = PageGetItemId(Cpage,
 							ItemPointerGetOffsetNumber(&(tuple.t_self)));
@@ -1512,7 +1512,7 @@ repair_frag(VRelStats *vacrelstats, Relation onerel,
 						PageSetLSN(ToPage, recptr);
 						PageSetSUI(ToPage, ThisStartUpID);
 					}
-					END_CRIT_CODE;
+					END_CRIT_SECTION();
 
 					if (((int) destvacpage->blkno) > last_move_dest_block)
 						last_move_dest_block = destvacpage->blkno;
@@ -1637,7 +1637,7 @@ repair_frag(VRelStats *vacrelstats, Relation onerel,
 			newtup.t_data->t_infomask |= HEAP_MOVED_IN;
 
 			/* NO ELOG(ERROR) TILL CHANGES ARE LOGGED */
-			START_CRIT_CODE;
+			START_CRIT_SECTION();
 
 			/* add tuple to the page */
 			newoff = PageAddItem(ToPage, (Item) newtup.t_data, tuple_len,
@@ -1675,7 +1675,7 @@ failed to add item with len = %lu to page %u (free space %lu, nusd %u, noff %u)"
 				PageSetLSN(ToPage, recptr);
 				PageSetSUI(ToPage, ThisStartUpID);
 			}
-			END_CRIT_CODE;
+			END_CRIT_SECTION();
 
 			cur_page->offsets_used++;
 			num_moved++;
@@ -1905,7 +1905,7 @@ failed to add item with len = %lu to page %u (free space %lu, nusd %u, noff %u)"
 
 			buf = ReadBuffer(onerel, vacpage->blkno);
 			LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
-			START_CRIT_CODE;
+			START_CRIT_SECTION();
 			page = BufferGetPage(buf);
 			num_tuples = 0;
 			for (offnum = FirstOffsetNumber;
@@ -1941,7 +1941,7 @@ failed to add item with len = %lu to page %u (free space %lu, nusd %u, noff %u)"
 				PageSetLSN(page, recptr);
 				PageSetSUI(page, ThisStartUpID);
 			}
-			END_CRIT_CODE;
+			END_CRIT_SECTION();
 			LockBuffer(buf, BUFFER_LOCK_UNLOCK);
 			WriteBuffer(buf);
 		}
@@ -2056,7 +2056,7 @@ vacuum_page(Relation onerel, Buffer buffer, VacPage vacpage)
 	/* There shouldn't be any tuples moved onto the page yet! */
 	Assert(vacpage->offsets_used == 0);
 
-	START_CRIT_CODE;
+	START_CRIT_SECTION();
 	for (i = 0; i < vacpage->offsets_free; i++)
 	{
 		itemid = &(((PageHeader) page)->pd_linp[vacpage->offsets[i] - 1]);
@@ -2070,7 +2070,7 @@ vacuum_page(Relation onerel, Buffer buffer, VacPage vacpage)
 		PageSetLSN(page, recptr);
 		PageSetSUI(page, ThisStartUpID);
 	}
-	END_CRIT_CODE;
+	END_CRIT_SECTION();
 
 }
 
diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c
index 6ba74f5e06..2be519193b 100644
--- a/src/backend/storage/buffer/bufmgr.c
+++ b/src/backend/storage/buffer/bufmgr.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/storage/buffer/bufmgr.c,v 1.102 2001/01/08 18:31:49 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/storage/buffer/bufmgr.c,v 1.103 2001/01/12 21:53:57 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -404,8 +404,7 @@ BufferAlloc(Relation reln,
 			 */
 			if ((buf->flags & BM_IO_ERROR) != 0)
 			{
-				PrivateRefCount[BufferDescriptorGetBuffer(buf) - 1] = 0;
-				buf->refcount--;
+				UnpinBuffer(buf);
 				buf = (BufferDesc *) NULL;
 				continue;
 			}
@@ -869,8 +868,10 @@ WaitIO(BufferDesc *buf, SPINLOCK spinlock)
 	while ((buf->flags & BM_IO_IN_PROGRESS) != 0)
 	{
 		SpinRelease(spinlock);
+		START_CRIT_SECTION();	/* don't want to die() holding the lock... */
 		S_LOCK(&(buf->io_in_progress_lock));
 		S_UNLOCK(&(buf->io_in_progress_lock));
+		END_CRIT_SECTION();
 		SpinAcquire(spinlock);
 	}
 }
@@ -921,14 +922,11 @@ ResetBufferUsage()
  *		ResetBufferPool
  *
  *		This routine is supposed to be called when a transaction aborts.
- *		it will release all the buffer pins held by the transaction.
+ *		It will release all the buffer pins held by the transaction.
  *		Currently, we also call it during commit if BufferPoolCheckLeak
  *		detected a problem --- in that case, isCommit is TRUE, and we
  *		only clean up buffer pin counts.
  *
- * During abort, we also forget any pending fsync requests.  Dirtied buffers
- * will still get written, eventually, but there will be no fsync for them.
- *
  * ----------------------------------------------
  */
 void
@@ -943,6 +941,7 @@ ResetBufferPool(bool isCommit)
 			BufferDesc *buf = &BufferDescriptors[i];
 
 			SpinAcquire(BufMgrLock);
+			PrivateRefCount[i] = 0;
 			Assert(buf->refcount > 0);
 			buf->refcount--;
 			if (buf->refcount == 0)
@@ -952,7 +951,6 @@ ResetBufferPool(bool isCommit)
 			}
 			SpinRelease(BufMgrLock);
 		}
-		PrivateRefCount[i] = 0;
 	}
 
 	ResetLocalBufferPool();
@@ -1900,7 +1898,7 @@ SetBufferCommitInfoNeedsSave(Buffer buffer)
 }
 
 void
-UnlockBuffers()
+UnlockBuffers(void)
 {
 	BufferDesc *buf;
 	int			i;
@@ -1913,6 +1911,8 @@ UnlockBuffers()
 		Assert(BufferIsValid(i + 1));
 		buf = &(BufferDescriptors[i]);
 
+		START_CRIT_SECTION();	/* don't want to die() holding the lock... */
+
 		S_LOCK(&(buf->cntx_lock));
 
 		if (BufferLocks[i] & BL_R_LOCK)
@@ -1940,6 +1940,8 @@ UnlockBuffers()
 		S_UNLOCK(&(buf->cntx_lock));
 
 		BufferLocks[i] = 0;
+
+		END_CRIT_SECTION();
 	}
 }
 
@@ -1956,6 +1958,8 @@ LockBuffer(Buffer buffer, int mode)
 	buf = &(BufferDescriptors[buffer - 1]);
 	buflock = &(BufferLocks[buffer - 1]);
 
+	START_CRIT_SECTION();		/* don't want to die() holding the lock... */
+
 	S_LOCK(&(buf->cntx_lock));
 
 	if (mode == BUFFER_LOCK_UNLOCK)
@@ -1979,6 +1983,7 @@ LockBuffer(Buffer buffer, int mode)
 		else
 		{
 			S_UNLOCK(&(buf->cntx_lock));
+			END_CRIT_SECTION();
 			elog(ERROR, "UNLockBuffer: buffer %lu is not locked", buffer);
 		}
 	}
@@ -1990,7 +1995,9 @@ LockBuffer(Buffer buffer, int mode)
 		while (buf->ri_lock || buf->w_lock)
 		{
 			S_UNLOCK(&(buf->cntx_lock));
+			END_CRIT_SECTION();
 			S_LOCK_SLEEP(&(buf->cntx_lock), i++);
+			START_CRIT_SECTION();
 			S_LOCK(&(buf->cntx_lock));
 		}
 		(buf->r_locks)++;
@@ -2016,7 +2023,9 @@ LockBuffer(Buffer buffer, int mode)
 				buf->ri_lock = true;
 			}
 			S_UNLOCK(&(buf->cntx_lock));
+			END_CRIT_SECTION();
 			S_LOCK_SLEEP(&(buf->cntx_lock), i++);
+			START_CRIT_SECTION();
 			S_LOCK(&(buf->cntx_lock));
 		}
 		buf->w_lock = true;
@@ -2038,10 +2047,12 @@ LockBuffer(Buffer buffer, int mode)
 	else
 	{
 		S_UNLOCK(&(buf->cntx_lock));
+		END_CRIT_SECTION();
 		elog(ERROR, "LockBuffer: unknown lock mode %d", mode);
 	}
 
 	S_UNLOCK(&(buf->cntx_lock));
+	END_CRIT_SECTION();
 }
 
 /*
@@ -2062,7 +2073,9 @@ static bool IsForInput;
  *	BM_IO_IN_PROGRESS mask is not set for the buffer
  *	The buffer is Pinned
  *
-*/
+ * Because BufMgrLock is held, we are already in a CRIT_SECTION here,
+ * and do not need another.
+ */
 static void
 StartBufferIO(BufferDesc *buf, bool forInput)
 {
@@ -2094,7 +2107,9 @@ StartBufferIO(BufferDesc *buf, bool forInput)
  *	BufMgrLock is held
  *	The buffer is Pinned
  *
-*/
+ * Because BufMgrLock is held, we are already in a CRIT_SECTION here,
+ * and do not need another.
+ */
 static void
 TerminateBufferIO(BufferDesc *buf)
 {
@@ -2110,7 +2125,9 @@ TerminateBufferIO(BufferDesc *buf)
  *	BufMgrLock is held
  *	The buffer is Pinned
  *
-*/
+ * Because BufMgrLock is held, we are already in a CRIT_SECTION here,
+ * and do not need another.
+ */
 static void
 ContinueBufferIO(BufferDesc *buf, bool forInput)
 {
@@ -2132,7 +2149,7 @@ InitBufferIO(void)
  *	This function is called from ProcReleaseSpins().
  *	BufMgrLock isn't held when this function is called.
  *
- *	If I/O was in progress, BM_IO_ERROR is always set.
+ *	If I/O was in progress, we always set BM_IO_ERROR.
  */
 void
 AbortBufferIO(void)
@@ -2141,8 +2158,8 @@ AbortBufferIO(void)
 
 	if (buf)
 	{
-		Assert(buf->flags & BM_IO_IN_PROGRESS);
 		SpinAcquire(BufMgrLock);
+		Assert(buf->flags & BM_IO_IN_PROGRESS);
 		if (IsForInput)
 			Assert(!(buf->flags & BM_DIRTY) && !(buf->cntxDirty));
 		else
diff --git a/src/backend/storage/file/fd.c b/src/backend/storage/file/fd.c
index 3cff793212..9ad40849eb 100644
--- a/src/backend/storage/file/fd.c
+++ b/src/backend/storage/file/fd.c
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/storage/file/fd.c,v 1.69 2000/12/08 22:21:32 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/storage/file/fd.c,v 1.70 2001/01/12 21:53:58 tgl Exp $
  *
  * NOTES:
  *
@@ -770,7 +770,11 @@ FileClose(File file)
 	 * Delete the file if it was temporary
 	 */
 	if (VfdCache[file].fdstate & FD_TEMPORARY)
+	{
+		/* reset flag so that die() interrupt won't cause problems */
+		VfdCache[file].fdstate &= ~FD_TEMPORARY;
 		unlink(VfdCache[file].fileName);
+	}
 
 	/*
 	 * Return the Vfd slot to the free list
@@ -1049,7 +1053,8 @@ AllocateFile(char *name, char *mode)
 TryAgain:
 	if ((file = fopen(name, mode)) != NULL)
 	{
-		allocatedFiles[numAllocatedFiles++] = file;
+		allocatedFiles[numAllocatedFiles] = file;
+		numAllocatedFiles++;
 		return file;
 	}
 
@@ -1080,7 +1085,8 @@ FreeFile(FILE *file)
 	{
 		if (allocatedFiles[i] == file)
 		{
-			allocatedFiles[i] = allocatedFiles[--numAllocatedFiles];
+			numAllocatedFiles--;
+			allocatedFiles[i] = allocatedFiles[numAllocatedFiles];
 			break;
 		}
 	}
diff --git a/src/backend/storage/ipc/spin.c b/src/backend/storage/ipc/spin.c
index 554eeba797..ed71d79ad9 100644
--- a/src/backend/storage/ipc/spin.c
+++ b/src/backend/storage/ipc/spin.c
@@ -14,7 +14,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/storage/ipc/Attic/spin.c,v 1.27 2000/12/11 00:49:52 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/storage/ipc/Attic/spin.c,v 1.28 2001/01/12 21:53:59 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -144,8 +144,21 @@ SpinAcquire(SPINLOCK lockid)
 	SLock	   *slckP = &(SLockArray[lockid]);
 
 	PRINT_SLDEBUG("SpinAcquire", lockid, slckP);
+	/*
+	 * Lock out die() until we exit the critical section protected by the
+	 * spinlock.  This ensures that die() will not interrupt manipulations
+	 * of data structures in shared memory.  We don't want die() to
+	 * interrupt this routine between S_LOCK and PROC_INCR_SLOCK, either,
+	 * so must do it before acquiring the lock, not after.
+	 */
+	START_CRIT_SECTION();
+	/*
+	 * Acquire the lock, then record that we have done so (for recovery
+	 * in case of elog(ERROR) during the critical section).
+	 */
 	S_LOCK(&(slckP->shlock));
 	PROC_INCR_SLOCK(lockid);
+
     PRINT_SLDEBUG("SpinAcquire/done", lockid, slckP);
 }
 
@@ -154,15 +167,22 @@ SpinRelease(SPINLOCK lockid)
 {
 	SLock	   *slckP = &(SLockArray[lockid]);
 
+    PRINT_SLDEBUG("SpinRelease", lockid, slckP);
 	/*
 	 * Check that we are actually holding the lock we are releasing. This
 	 * can be done only after MyProc has been initialized.
 	 */
     Assert(!MyProc || MyProc->sLocks[lockid] > 0);
-
+	/*
+	 * Record that we no longer hold the spinlock, and release it.
+	 */
 	PROC_DECR_SLOCK(lockid);
-    PRINT_SLDEBUG("SpinRelease", lockid, slckP);
 	S_UNLOCK(&(slckP->shlock));
+	/*
+	 * Exit the critical section entered in SpinAcquire().
+	 */
+	END_CRIT_SECTION();
+
     PRINT_SLDEBUG("SpinRelease/done", lockid, slckP);
 }
 
@@ -187,7 +207,7 @@ SpinRelease(SPINLOCK lockid)
  *
  * Note that the SpinLockIds array is not in shared memory; it is filled
  * by the postmaster and then inherited through fork() by backends.  This
- * is OK because its contents do not change after system startup.
+ * is OK because its contents do not change after shmem initialization.
  */
 
 #define SPINLOCKS_PER_SET  PROC_NSEMS_PER_SET
@@ -285,6 +305,8 @@ SpinFreeAllSemaphores(void)
 		if (SpinLockIds[i] >= 0)
 			IpcSemaphoreKill(SpinLockIds[i]);
 	}
+	free(SpinLockIds);
+	SpinLockIds = NULL;
 }
 
 /*
@@ -295,6 +317,8 @@ SpinFreeAllSemaphores(void)
 void
 SpinAcquire(SPINLOCK lock)
 {
+	/* See the TAS() version of this routine for commentary */
+	START_CRIT_SECTION();
 	IpcSemaphoreLock(SpinLockIds[0], lock);
 	PROC_INCR_SLOCK(lock);
 }
@@ -307,15 +331,18 @@ SpinAcquire(SPINLOCK lock)
 void
 SpinRelease(SPINLOCK lock)
 {
+	/* See the TAS() version of this routine for commentary */
 #ifdef USE_ASSERT_CHECKING
 	/* Check it's locked */
 	int			semval;
 
 	semval = IpcSemaphoreGetValue(SpinLockIds[0], lock);
 	Assert(semval < 1);
+    Assert(!MyProc || MyProc->sLocks[lockid] > 0);
 #endif
 	PROC_DECR_SLOCK(lock);
 	IpcSemaphoreUnlock(SpinLockIds[0], lock);
+	END_CRIT_SECTION();
 }
 
 /*
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 2730c8811e..baa31413e2 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/storage/lmgr/proc.c,v 1.90 2001/01/09 09:38:57 inoue Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/storage/lmgr/proc.c,v 1.91 2001/01/12 21:53:59 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -48,7 +48,7 @@
  *		This is so that we can support more backends. (system-wide semaphore
  *		sets run out pretty fast.)				  -ay 4/95
  *
- * $Header: /cvsroot/pgsql/src/backend/storage/lmgr/proc.c,v 1.90 2001/01/09 09:38:57 inoue Exp $
+ * $Header: /cvsroot/pgsql/src/backend/storage/lmgr/proc.c,v 1.91 2001/01/12 21:53:59 tgl Exp $
  */
 #include "postgres.h"
 
@@ -241,7 +241,6 @@ InitProcess(void)
 	MemSet(MyProc->sLocks, 0, sizeof(MyProc->sLocks));
 	MyProc->sLocks[ProcStructLock] = 1;
 
-
 	if (IsUnderPostmaster)
 	{
 		IpcSemaphoreId	semId;
@@ -264,23 +263,16 @@ InitProcess(void)
 	else
 		MyProc->sem.semId = -1;
 
-	/* ----------------------
-	 * Release the lock.
-	 * ----------------------
-	 */
-	SpinRelease(ProcStructLock);
-
 	MyProc->pid = MyProcPid;
 	MyProc->databaseId = MyDatabaseId;
 	MyProc->xid = InvalidTransactionId;
 	MyProc->xmin = InvalidTransactionId;
 
-	/* ----------------
-	 * Start keeping spin lock stats from here on.	Any botch before
-	 * this initialization is forever botched
-	 * ----------------
+	/* ----------------------
+	 * Release the lock.
+	 * ----------------------
 	 */
-	MemSet(MyProc->sLocks, 0, MAX_SPINS * sizeof(*MyProc->sLocks));
+	SpinRelease(ProcStructLock);
 
 	/* -------------------------
 	 * Install ourselves in the shmem index table.	The name to
@@ -412,15 +404,6 @@ ProcKill(int exitStatus, Datum pid)
 {
 	PROC	   *proc;
 
-	/* --------------------
-	 * If this is a FATAL exit the postmaster will have to kill all the
-	 * existing backends and reinitialize shared memory.  So we don't
-	 * need to do anything here.
-	 * --------------------
-	 */
-	if (exitStatus != 0)
-		return;
-
 	if ((int) pid == MyProcPid)
 	{
 		proc = MyProc;
diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index a73ba4df4a..1a0aa5d0cd 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/tcop/postgres.c,v 1.199 2001/01/07 04:17:29 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/tcop/postgres.c,v 1.200 2001/01/12 21:53:59 tgl Exp $
  *
  * NOTES
  *	  this is the "main" module of the postgres backend and
@@ -982,7 +982,7 @@ die(SIGNAL_ARGS)
 
 /*
  * This is split out of die() so that it can be invoked later from
- * END_CRIT_CODE.
+ * END_CRIT_SECTION().
  */
 void
 ForceProcDie(void)
@@ -1683,7 +1683,7 @@ PostgresMain(int argc, char *argv[], int real_argc, char *real_argv[], const cha
 	if (!IsUnderPostmaster)
 	{
 		puts("\nPOSTGRES backend interactive interface ");
-		puts("$Revision: 1.199 $ $Date: 2001/01/07 04:17:29 $\n");
+		puts("$Revision: 1.200 $ $Date: 2001/01/12 21:53:59 $\n");
 	}
 
 	/*
diff --git a/src/backend/utils/cache/temprel.c b/src/backend/utils/cache/temprel.c
index a0066f2eaf..b1580d65b4 100644
--- a/src/backend/utils/cache/temprel.c
+++ b/src/backend/utils/cache/temprel.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/utils/cache/Attic/temprel.c,v 1.32 2000/12/22 23:12:07 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/utils/cache/Attic/temprel.c,v 1.33 2001/01/12 21:54:00 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -263,8 +263,6 @@ AtEOXact_temp_relations(bool isCommit)
 			temp_rel->created_in_cur_xact)
 		{
 			/* This entry must be removed */
-			pfree(temp_rel);
-			/* remove from linked list */
 			if (prev != NIL)
 			{
 				lnext(prev) = lnext(l);
@@ -277,6 +275,7 @@ AtEOXact_temp_relations(bool isCommit)
 				pfree(l);
 				l = temp_rels;
 			}
+			pfree(temp_rel);
 		}
 		else
 		{
diff --git a/src/backend/utils/init/postinit.c b/src/backend/utils/init/postinit.c
index c8bd8a0d26..6248c7bea6 100644
--- a/src/backend/utils/init/postinit.c
+++ b/src/backend/utils/init/postinit.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/utils/init/postinit.c,v 1.76 2000/12/18 00:44:48 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/utils/init/postinit.c,v 1.77 2001/01/12 21:54:00 tgl Exp $
  *
  *
  *-------------------------------------------------------------------------
@@ -395,11 +395,12 @@ ShutdownPostgres(void)
 	 * We don't want to do any inessential cleanup, since that just raises
 	 * the odds of failure --- but there's some stuff we need to do.
 	 *
-	 * Release any spinlocks that we may hold.  This is a kluge to improve
-	 * the odds that we won't get into a self-made stuck spinlock scenario
-	 * while trying to shut down.
+	 * Release any spinlocks or buffer context locks we might be holding.
+	 * This is a kluge to improve the odds that we won't get into a self-made
+	 * stuck-spinlock scenario while trying to shut down.
 	 */
 	ProcReleaseSpins(NULL);
+	UnlockBuffers();
 	/*
 	 * In case a transaction is open, delete any files it created.  This
 	 * has to happen before bufmgr shutdown, so having smgr register a
diff --git a/src/backend/utils/mmgr/aset.c b/src/backend/utils/mmgr/aset.c
index cdb2601e38..5c0cf30745 100644
--- a/src/backend/utils/mmgr/aset.c
+++ b/src/backend/utils/mmgr/aset.c
@@ -11,7 +11,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/utils/mmgr/aset.c,v 1.36 2001/01/06 21:59:39 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/utils/mmgr/aset.c,v 1.37 2001/01/12 21:54:01 tgl Exp $
  *
  * NOTE:
  *	This is a new (Feb. 05, 1999) implementation of the allocation set
@@ -384,6 +384,11 @@ AllocSetReset(MemoryContext context)
 	AllocSetCheck(context);
 #endif
 
+	/* Clear chunk freelists */
+	MemSet(set->freelist, 0, sizeof(set->freelist));
+	/* New blocks list is either empty or just the keeper block */
+	set->blocks = set->keeper;
+
 	while (block != NULL)
 	{
 		AllocBlock	next = block->next;
@@ -411,11 +416,6 @@ AllocSetReset(MemoryContext context)
 		}
 		block = next;
 	}
-
-	/* Now blocks list is either empty or just the keeper block */
-	set->blocks = set->keeper;
-	/* Clear chunk freelists in any case */
-	MemSet(set->freelist, 0, sizeof(set->freelist));
 }
 
 /*
@@ -439,6 +439,11 @@ AllocSetDelete(MemoryContext context)
 	AllocSetCheck(context);
 #endif
 
+	/* Make it look empty, just in case... */
+	MemSet(set->freelist, 0, sizeof(set->freelist));
+	set->blocks = NULL;
+	set->keeper = NULL;
+
 	while (block != NULL)
 	{
 		AllocBlock	next = block->next;
@@ -450,11 +455,6 @@ AllocSetDelete(MemoryContext context)
 		free(block);
 		block = next;
 	}
-
-	/* Make it look empty, just in case... */
-	set->blocks = NULL;
-	MemSet(set->freelist, 0, sizeof(set->freelist));
-	set->keeper = NULL;
 }
 
 /*
@@ -605,15 +605,16 @@ AllocSetAlloc(MemoryContext context, Size size)
 				}
 
 				chunk = (AllocChunk) (block->freeptr);
+
+				block->freeptr += (availchunk + ALLOC_CHUNKHDRSZ);
+				availspace -= (availchunk + ALLOC_CHUNKHDRSZ);
+
 				chunk->size = availchunk;
 #ifdef MEMORY_CONTEXT_CHECKING
 				chunk->requested_size = 0; /* mark it free */
 #endif
 				chunk->aset = (void *) set->freelist[a_fidx];
 				set->freelist[a_fidx] = chunk;
-
-				block->freeptr += (availchunk + ALLOC_CHUNKHDRSZ);
-				availspace -= (availchunk + ALLOC_CHUNKHDRSZ);
 			}
 
 			/* Mark that we need to create a new block */
@@ -696,6 +697,10 @@ AllocSetAlloc(MemoryContext context, Size size)
 	 * OK, do the allocation
 	 */
 	chunk = (AllocChunk) (block->freeptr);
+
+	block->freeptr += (chunk_size + ALLOC_CHUNKHDRSZ);
+	Assert(block->freeptr <= block->endptr);
+
 	chunk->aset = (void *) set;
 	chunk->size = chunk_size;
 #ifdef MEMORY_CONTEXT_CHECKING
@@ -705,9 +710,6 @@ AllocSetAlloc(MemoryContext context, Size size)
 		((char *) AllocChunkGetPointer(chunk))[size] = 0x7E;
 #endif	
 
-	block->freeptr += (chunk_size + ALLOC_CHUNKHDRSZ);
-	Assert(block->freeptr <= block->endptr);
-
 	AllocAllocInfo(set, chunk);
 	return AllocChunkGetPointer(chunk);
 }
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 88268b0b0b..7736ec92e8 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -3,7 +3,7 @@
  *
  * PostgreSQL transaction log manager
  *
- * $Header: /cvsroot/pgsql/src/include/access/xlog.h,v 1.15 2000/12/28 13:00:25 vadim Exp $
+ * $Header: /cvsroot/pgsql/src/include/access/xlog.h,v 1.16 2001/01/12 21:54:01 tgl Exp $
  */
 #ifndef XLOG_H
 #define XLOG_H
@@ -101,7 +101,7 @@ typedef XLogPageHeaderData *XLogPageHeader;
 extern	StartUpID	ThisStartUpID;	/* current SUI */
 extern	bool		InRecovery;
 extern	XLogRecPtr	MyLastRecPtr;
-extern	uint32		CritSectionCount;
+extern volatile uint32		CritSectionCount;
 
 typedef struct RmgrData
 {
diff --git a/src/include/utils/elog.h b/src/include/utils/elog.h
index e7305d67fc..da9178b276 100644
--- a/src/include/utils/elog.h
+++ b/src/include/utils/elog.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2000, PostgreSQL, Inc
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: elog.h,v 1.22 2001/01/07 04:17:28 tgl Exp $
+ * $Id: elog.h,v 1.23 2001/01/12 21:54:01 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -34,16 +34,15 @@ extern int Use_syslog;
  * ProcDiePending will be honored at critical section exit,
  * but QueryCancel is only checked at specified points.
  */
-extern uint32 CritSectionCount;	/* duplicates access/xlog.h */
+extern volatile uint32 CritSectionCount;	/* duplicates access/xlog.h */
 extern volatile bool ProcDiePending;
 extern void ForceProcDie(void);	/* in postgres.c */
 
-#define	START_CRIT_CODE		(CritSectionCount++)
+#define	START_CRIT_SECTION()  (CritSectionCount++)
 
-#define END_CRIT_CODE	\
+#define END_CRIT_SECTION() \
 	do { \
-		if (CritSectionCount == 0) \
-			elog(STOP, "Not in critical section"); \
+		Assert(CritSectionCount > 0); \
 		CritSectionCount--; \
 		if (CritSectionCount == 0 && ProcDiePending) \
 			ForceProcDie(); \