mscp_tape.c

<B>Digital的Unix操作系统VAX 4.2源码</B>

#ifndef	lint 
static char *sccsid = "@(#)mscp_tape.c	4.5    (ULTRIX)        12/20/90";
#endif	lint

/************************************************************************
 *                                                                      *
 *                      Copyright (c) 1987 - 1990 by                    *
 *              Digital Equipment Corporation, Maynard, MA              *
 *                      All rights reserved.                            *
 *                                                                      *
 *   This software is furnished under a license and may be used and     *
 *   copied  only  in accordance with the terms of such license and     *
 *   with the  inclusion  of  the  above  copyright  notice.   This     *
 *   software  or  any  other copies thereof may not be provided or     *
 *   otherwise made available to any other person.  No title to and     *
 *   ownership of the software is hereby transferred.                   *
 *                                                                      *
 *   The information in this software is subject to change  without     *
 *   notice  and should not be construed as a commitment by Digital     *
 *   Equipment Corporation.                                             *
 *                                                                      *
 *   Digital assumes no responsibility for the use  or  reliability     *
 *   of its software on equipment which is not supplied by Digital.     *
 *                                                                      *
 ************************************************************************
 *
 *
 *   Facility:	Systems Communication Architecture
 *		Tape Class Driver
 *
 *   Abstract:	This module contains the 
 *		routines specific to the tape
 *		variant of MSCP.
 *
 *   Author:	Robin Lewis	3/2/1987
 *
 *   History:
 *
 *   08-Dec-1990	Tom Tierney
 *	Fixed recovery problem: removed checks for recovery state in
 *	tmscp_availcm.  In this way, available commands will be issued
 *	to units failing recovery and available end message processing
 *	will mark the unit appropriately and then continue recovery
 *	processing.  The mscp_restart_next routine should only be called
 *	after all previously online units had attempted recovery.
 *
 *	Also updated get unit status recovery table so that an online
 *	error (EV_ONLERROR) will cause available processing to occur and
 *	updated online end message processing to return EV_ONLERROR 
 *	when online fails during the unit recovery process. 
 * 
 *    4-Dec-1990	Brian Nadeau
 *	Add a return to tmscpioctl so lint will not complain.
 *
 *   26-Nov-1990	Brian Nadeau
 *	Ignore mscp_byte_cnt value when a serious exception occurs.
 *	Some controllers like the TQK50 fail to zero it after the
 *	exception.
 *
 *   05-Nov-1990	Tom Tierney
 *	Corrected transferem routine to copy byte count from the
 *	response packet's byte count field for all transfer commands
 *	except for "access" commands which get their byte count from
 *	the end packet's tape record field.
 *
 *   18-Dec-1989	Tim Burke
 *	Increase the timeout period of reposition commands from 20 minutes
 *	to 60 minutes.
 *
 *   06-Nov-1989	Tim Burke
 *	Set the exclusive access modifier in the setunitcm routine.
 *
 *   11-Sep-1989	Tim Burke
 *	Provide support for the following TA90 densities:
 *	MSCP_TF_NDCP, MSCP_TF_ENHD, and MSCP_TF_EDCP.
 *
 *   23-Aug-1989	Tim Burke
 *	Software workaround to a TU81+ microcode bug.  Do not allow the TU81
 *	to use caching because the command issued after the flush command will
 *	hang in the drive.
 *
 *   18-Aug-1989	Tim Burke
 *	In tmscp_setunitcm() only specify a tape format if positioned at
 *	BOT.  This prevents the command from being rejected with an invalid
 *	command, invalid format subcode.
 *
 *   01-Aug-1989	Tim Burke
 *	Fixed assignment of the mt_dsreg in mtiocget to properly contain the
 *	tms_flags field in the upper 8 bits of the field.
 *
 *   21-Jul-1989	David E. Eiche		DEE0070
 *	Changed various field names to conform to the T/MSCP preferred
 *	mnemonics, eliminate multiple levels of qualification, and
 *	eliminate multiple names for the same field.
 *	
 *   20-Jun-1989	Tim Burke
 *	Added TQK7L support.  This consists of loader present bit and 
 *	logging of loader errors.  Changed debugging printf's to be run off
 *	levels as specified by the tmscpdebug variable.  Added the kernel
 *	variable tmscptestcache which when set forces the drive to always run
 *	in caching mode, this is intended for debug and analysis usage only.
 *
 *   05-May-1989	Tim Burke
 *	Merged 3.1 deltas into pu and isis pools.
 *	Bug fix:  In transfercm if a non-nbuf read is being done and the 
 *	previous read hit a tape mark, clear the serious exception to allow
 *	the next read to be done on the first record of the next file.
 *
 *   14-Apr-1989	Tim Burke
 *	Added caching support to allow the use of controller read-ahead and 
 *	write-behind caching.  Changes involve adding MTFLUSH mtop, checking
 *	cache status in close routine, and keeping track of when writes could
 *	be pending in the controller's write back cache.
 *
 *   15-Mar-1989	Tim Burke
 *	Changed splx( IPL_SCS ) to Splscs();
 *
 *   07-Mar-1989	Todd M. Katz		TMK0002
 *	Include header file ../vaxmsi/msisysap.h.
 *
 *   28-Feb-1989	Tim Burke
 *	Prevent panics in recovery code.  Previously a panic would occur if
 *	more than one unit was online and needs recovery.  The fix involved
 *	recycling the rspid in tmscp_recovnext, and changing the recovery
 *	state table entries associated with the EV_ONLDONEXT from tmscp_invevent
 *	to tmscp_onlinecm.  This change was done on states 3 and 4.
 *
 *   27-Feb-1989	Tim Burke
 *	Prevent panics in recovery code by properly returning from the 
 *	tmscp_availcm routine if the reposition to last known position command
 *	fails.  Return to prevent sending a message when no resources are
 *	allocated to do so.
 *
 *   02-Feb-1989	Tim Burke
 *	Clear the up->Tflags.tms_wait flag in the tmscp_setunitem routine to
 *	prevent hanging in the tmscpopen routine.  Add a check in tmscpopen to
 *	see if the unit goes available unexpectadly.  Add missing subcode of
 *	MSCP_SC_EXUSE to the offline status code in check_return.
 *
 *   05-Jan-1988	Tim Burke
 *	In the transferem routine setup rp->p1 with the resid count so that it
 *	can be stuffed back into the buf struct in mscp_dealloc_reqb.  Also in
 *	this routine do not clear the BOM flag if you are still at BOT (if the
 *	operation fails).
 * 
 *	Added the Time_Check macro to log an error if the end message does not
 *	come back within the propper time interval.
 *
 *	Initilize the tms_status field in the unit block which will cause ioctls
 *	to fail if the device goes offline after it is opened.
 *
 *	Clear the serious exception state in the MTFSR and MTBSR ioctls if a
 *	tape mark has been encountered.
 *
 *	Added MSCP_ST_LOADR case to the check_return() routine. 
 *
 *   20-Dec-1988	Tim Burke
 *	Change MTFSR and MTBSR to move tape records and not tape objects.  This
 *	is done to be consistent with other drivers which don't traverse tape
 *	marks with record movement commands.  Change to return the propper
 *	resid field in MTIOCGET.
 *
 *   03-Oct-1988	Tim Burke
 *	Added state table and command routine for the set unit command.
 *	In tmscpopen() if the device is already online at position 0,
 *	set the density.  This is a software workaround to the TU81+
 *	failing to clear the online status via the avail command.
 *
 *   29-Sep-1988	Tim Burke
 *	Don't clear tms_category_flags in the onlineinit routine.  This would
 *	cause the tape density returned in DEVIOCGET to be wrong if the tape
 *	wasn't sitting at BOT.
 *
 *   14-Sep-1988	Tim Burke
 *	Clear tape written flag when a reposition command has changed the
 *	present position.  This prevents the close routine from improperly 
 * 	laying down tape marks in the wrong place.
 *
 *   17-Aug-1988	David E. Eiche		DEE0051
 *	Change state definitions to use ST_CMN_INITIAL so that
 *	recovery can rely on the initial state in any state table
 *	to be the same.  Also change unused events in the recovery
 *	state table to dispatch to the invalid event routine.
 *
 *   10-Aug-1988	David E. Eiche		DEE0050
 *	Change routines tmscp_recov_init and tmscp_recov_next
 *	to store the tape unit position only after finding a
 *	tape unit in the appropriate state.
 *
 *   05-Aug-1988	Tim Burke
 *	Maintain one copy of the online/offline status instead of using
 *	up->tms_flags with DEV_OFFLINE and up->flags.online; only keep 
 *	up->flags.online current and setup tms_flags in the ioctl routines
 *	as needed.
 *
 *   18-Jul-1988	Tim Burke
 *	In the open routine, derive the online status directly from the
 *	get unit status command.  Set inuse early in open routine to avoid
 *	race condition.  Allow for handling of non-EOT serious exceptions.
 *
 *   17-Jul-1988	David E. Eiche		DEE0045
 *	Change get device information ioctl to get model name from
 *	the connection block.
 *
 *   23-Jun-1988	Tim Burke
 *	Allow MTCLX and MTCLS ioctls by SU only.  Don't zero out tape
 *	attributes in the end message.
 *
 *   09-Jun-1988	Robin
 *	Added code that:stopped panic by setting a pointer value before it
 *	is used; returnes from ioctl calls with the correct status; sets up
 *	the hardware cache the correct way.
 *
 *   02-Jun-1988     Ricky S. Palmer
 *      Removed inclusion of header file ../vaxmsi/msisysap.h
 *
 *   20-Apr-1988	Tim Burke
 *	Setup residual count on partial writes in tmscp_transferem.
 *
 *   08-Apr-1988	Robin
 *	added some debug prints around tape density code.
 *
 *   04-Mar-1988	Robin
 *	In checking returns the write lock condition was set but it was only
 *	reset in close.  Now I reset the write lock flags and then reset them
 *	if the unit is still write locked.
 *
 *   01-Mar-1988	Robin
 *	We have a bug in the TU81+ which causes the path to crash if we
 *	issue two available commands and then do a get_command-status
 *	on the second.  The command status returned is zero (unknown command)
 *	and thats a problem.  To work around the problem I now must wait for
 *	the tape to rewind before letting close finish.
 *
 *   22-Feb-1988	Robin
 *	Changes the open routine to wait for the get unit status to finish.
 *	also changed the ioctl calls to get a rspid to check the return
 *	values.
 *
 *	The connection recovery code was added to bring a unit back online
 *	and reposition to a know position on the tape; then the outstanding
 *	I/O requests are re-issued.  Everything continues as before after
 *	the conection is recovered.
 *
 *
 *   02-Feb-1988	David E. Eiche		DEE0011
 *	Change tmscpstrategy to sleep if the request block is not
 *	available immediately.  Also remove code that initialized
 *	unused request block wait queue.
 *
 *   27-Jan-1988	Robin
 *	Removed the initialization routine calls in the open routine.  This
 *	will be done is start_sysap and mscp_systm_poll will break if we
 *	continue to do this.
 *
 *   15-Jan-1988	Todd M. Katz		TMK0001
 *	Include new header file ../vaxmsi/msisysap.h.
 *
 *   22-DEC-1987	Robin
 *	added B_error debug prints and fixed the DEVIOCGET ioctl
 *	DEV_CSE flag, it was set in the wrong word.
 */


/* Libraries and Include Files.
 */
#include	"../h/types.h"
#include	"../h/time.h"
#include	"../h/param.h"
#include	"../h/buf.h"
#include	"../h/errno.h"
#include	"../h/ioctl.h"
#include	"../h/devio.h"
#include	"../h/mtio.h"
#include	"../h/file.h"
#include	"../h/dump.h"
#include	"../h/systm.h"
#include	"../fs/ufs/fs.h"
#include	"../h/errlog.h"
#include	"../io/scs/sca.h"
#include	"../io/ci/cippdsysap.h"
#include	"../io/ci/cisysap.h"
#include        "../io/msi/msisysap.h"
#include	"../io/bi/bvpsysap.h"
#include	"../io/gvp/gvpsysap.h"
#include	"../io/uba/uqsysap.h"
#include	"../io/uba/ubavar.h"
#include	"../io/sysap/sysap.h"
#include	"../io/sysap/mscp_msg.h"
#include	"../io/sysap/mscp_defs.h"

/*
 * Caching control variable.  Setting this variable will always cause caching
 * to be used on this driver reguardless of calls to mtcache/mtnocache.  This
 * could prove useful at determining theoretical utility performance if they
 * utilized caching support.  Note that this should be used for debugging
 * and analysis because it opens a window of data integrity for utilities which
 * do not use mtflush; here there may be no indication of cache data loss to
 * the utility.
 */
int 	tmscptestcache = 0;
/* Debugging variables.  This value determines the debugging output level.
 * the larger the number, the more output.
 */
int 	tmscpdebug = 0;

#define TMSCPDEBUG
#ifdef TMSCPDEBUG

/*
 * Provide various levels of debugging printouts based on the value of
 * tmscpdebug.
 */
#define Dprint1 if ( tmscpdebug )      printf		/* Highest priority */
#define Dprint2 if ( tmscpdebug > 1 )  printf
#define Dprint3 if ( tmscpdebug > 2 )  printf
#define Dprint4 if ( tmscpdebug > 3 )  printf
#define Dprint5 if ( tmscpdebug > 4 )  printf
#define Dprint6 if ( tmscpdebug > 5 )  printf
#define Dprint7 if ( tmscpdebug > 6 )  printf
#define Dprint8 if ( tmscpdebug > 7 )  printf		/* Lowest priority */

/*
 * This macro is used to see if the timer has expired before the bit that
 * we are waiting for has cleared.  Typically the driver is waiting for an
 * end message for a particular command.  To prevent hanging you only wait
 * so long before giving up.
 */
#define Time_Check( Wait_For, Retry_Count, Error_String) { 		\
	if ((Wait_For) && ((Retry_Count) < 0)) { 			\
		mprintf("tmscp driver error: no end message for %s\n", 	\
			(Error_String));				\
	}}								

#else
#define Dprint1 ;
#define Dprint2 ;
#define Dprint3 ;
#define Dprint4 ;
#define Dprint5 ;
#define Dprint6 ;
#define Dprint7 ;
#define Dprint8 ;
#define Time_Check ;
#endif

/*
 * Evaluates to 1 if the unit in question is a TU81 drive.  This is being
 * done to provide software workarounds to hardware problems, hack, hack.
 */
#define IS_TU81_DRIVE( drive_model_name ) 				\
	(strncmp( drive_model_name, DEV_TU81, strlen(drive_model_name)) == 0)

/*
 * There have been cases where no end messages appear for outstanding commands.
 * As a result the utility program would end up hung in an unkillable state.
 * To avoid this problem (which shouldn't happen in the first place) impose
 * timers on how long to wait for the end message to return.
 *
 * Give reposition type commands a long time to complete.  On the TK70 a
 * forward skip command could take up to 57 minutes to complete (WOW).  This
 * is calculated as (600feet * 48tracks * 12inches) / (100ips * 60sec) = 57min.
 * Actual timing reveals that using 60 minutes is not enough to forward skip
 * file from the beginning to the last tape mark at the end of the tape.  So
 * use a value of 70 minutes to allow the needed time.
 */