Cancel pending fsync requests during WAL replay of DROP DATABASE, per bug

report from David Darville.  Back-patch as far as 8.1, which may or may not
have the problem but it seems a safe change anyway.

src/backend/commands/dbcommands.c

@@ -15,7 +15,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/dbcommands.c,v 1.173.2.2 2007/01/27 20:15:55 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/dbcommands.c,v 1.173.2.3 2007/04/12 15:04:47 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1375,6 +1375,12 @@ dbase_redo(XLogRecPtr lsn, XLogRecord *record)
 		 */
 		DropBuffers(xlrec->db_id);
 
+		/* Also, clean out any entries in the shared free space map */
+		FreeSpaceMapForgetDatabase(xlrec->db_id);
+
+		/* Also, clean out any fsync requests that might be pending in md.c */
+		ForgetDatabaseFsyncRequests(xlrec->db_id);
+
 		if (!rmtree(dst_path, true))
 			ereport(WARNING,
 					(errmsg("could not remove database directory \"%s\"",