tape.c

早期freebsd实现

/*-
 * Copyright (c) 1980, 1991, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifndef lint
static char sccsid[] = "@(#)tape.c	8.2 (Berkeley) 3/17/94";
#endif /* not lint */

#include <sys/param.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <sys/wait.h>
#ifdef sunos
#include <sys/vnode.h>

#include <ufs/fs.h>
#include <ufs/inode.h>
#else
#include <ufs/ffs/fs.h>
#include <ufs/ufs/dinode.h>
#endif

#include <protocols/dumprestore.h>

#include <errno.h>
#include <fcntl.h>
#include <setjmp.h>
#include <signal.h>
#include <stdio.h>
#ifdef __STDC__
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#else
int	write(), read();
#endif

#include "dump.h"
#include "pathnames.h"

int	writesize;		/* size of malloc()ed buffer for tape */
long	lastspclrec = -1;	/* tape block number of last written header */
int	trecno = 0;		/* next record to write in current block */
extern	long blocksperfile;	/* number of blocks per output file */
long	blocksthisvol;		/* number of blocks on current output file */
extern	int ntrec;		/* blocking factor on tape */
extern	int cartridge;
extern	char *host;
char	*nexttape;

static	int atomic __P((int (*)(), int, char *, int));
static	void doslave __P((int, int));
static	void enslave __P((void));
static	void flushtape __P((void));
static	void killall __P((void));
static	void rollforward __P((void));

/*
 * Concurrent dump mods (Caltech) - disk block reading and tape writing
 * are exported to several slave processes.  While one slave writes the
 * tape, the others read disk blocks; they pass control of the tape in
 * a ring via signals. The parent process traverses the filesystem and
 * sends writeheader()'s and lists of daddr's to the slaves via pipes.
 * The following structure defines the instruction packets sent to slaves.
 */
struct req {
	daddr_t dblk;
	int count;
};
int reqsiz;

#define SLAVES 3		/* 1 slave writing, 1 reading, 1 for slack */
struct slave {
	int tapea;		/* header number at start of this chunk */
	int count;		/* count to next header (used for TS_TAPE */
				/* after EOT) */
	int inode;		/* inode that we are currently dealing with */
	int fd;			/* FD for this slave */
	int pid;		/* PID for this slave */
	int sent;		/* 1 == we've sent this slave requests */
	int firstrec;		/* record number of this block */
	char (*tblock)[TP_BSIZE]; /* buffer for data blocks */
	struct req *req;	/* buffer for requests */
} slaves[SLAVES+1];
struct slave *slp;

char	(*nextblock)[TP_BSIZE];

int master;		/* pid of master, for sending error signals */
int tenths;		/* length of tape used per block written */
static int caught;	/* have we caught the signal to proceed? */
static int ready;	/* have we reached the lock point without having */
			/* received the SIGUSR2 signal from the prev slave? */
static jmp_buf jmpbuf;	/* where to jump to if we are ready when the */
			/* SIGUSR2 arrives from the previous slave */

int
alloctape()
{
	int pgoff = getpagesize() - 1;
	char *buf;
	int i;

	writesize = ntrec * TP_BSIZE;
	reqsiz = (ntrec + 1) * sizeof(struct req);
	/*
	 * CDC 92181's and 92185's make 0.8" gaps in 1600-bpi start/stop mode
	 * (see DEC TU80 User's Guide).  The shorter gaps of 6250-bpi require
	 * repositioning after stopping, i.e, streaming mode, where the gap is
	 * variable, 0.30" to 0.45".  The gap is maximal when the tape stops.
	 */
	if (blocksperfile == 0)
		tenths = writesize / density +
		    (cartridge ? 16 : density == 625 ? 5 : 8);
	/*
	 * Allocate tape buffer contiguous with the array of instruction
	 * packets, so flushtape() can write them together with one write().
	 * Align tape buffer on page boundary to speed up tape write().
	 */
	for (i = 0; i <= SLAVES; i++) {
		buf = (char *)
		    malloc((unsigned)(reqsiz + writesize + pgoff + TP_BSIZE));
		if (buf == NULL)
			return(0);
		slaves[i].tblock = (char (*)[TP_BSIZE])
		    (((long)&buf[ntrec + 1] + pgoff) &~ pgoff);
		slaves[i].req = (struct req *)slaves[i].tblock - ntrec - 1;
	}
	slp = &slaves[0];
	slp->count = 1;
	slp->tapea = 0;
	slp->firstrec = 0;
	nextblock = slp->tblock;
	return(1);
}

void
writerec(dp, isspcl)
	char *dp;
	int isspcl;
{

	slp->req[trecno].dblk = (daddr_t)0;
	slp->req[trecno].count = 1;
	*(union u_spcl *)(*(nextblock)++) = *(union u_spcl *)dp;
	if (isspcl)
		lastspclrec = spcl.c_tapea;
	trecno++;
	spcl.c_tapea++;
	if (trecno >= ntrec)
		flushtape();
}

void
dumpblock(blkno, size)
	daddr_t blkno;
	int size;
{
	int avail, tpblks, dblkno;

	dblkno = fsbtodb(sblock, blkno);
	tpblks = size >> tp_bshift;
	while ((avail = MIN(tpblks, ntrec - trecno)) > 0) {
		slp->req[trecno].dblk = dblkno;
		slp->req[trecno].count = avail;
		trecno += avail;
		spcl.c_tapea += avail;
		if (trecno >= ntrec)
			flushtape();
		dblkno += avail << (tp_bshift - dev_bshift);
		tpblks -= avail;
	}
}

int	nogripe = 0;

void
tperror(signo)
	int signo;
{

	if (pipeout) {
		msg("write error on %s\n", tape);
		quit("Cannot recover\n");
		/* NOTREACHED */
	}
	msg("write error %d blocks into volume %d\n", blocksthisvol, tapeno);
	broadcast("DUMP WRITE ERROR!\n");
	if (!query("Do you want to restart?"))
		dumpabort(0);
	msg("Closing this volume.  Prepare to restart with new media;\n");
	msg("this dump volume will be rewritten.\n");
	killall();
	nogripe = 1;
	close_rewind();
	Exit(X_REWRITE);
}

void
sigpipe(signo)
	int signo;
{

	quit("Broken pipe\n");
}

static void
flushtape()
{
	int i, blks, got;
	long lastfirstrec;

	int siz = (char *)nextblock - (char *)slp->req;

	slp->req[trecno].count = 0;			/* Sentinel */

	if (atomic(write, slp->fd, (char *)slp->req, siz) != siz)
		quit("error writing command pipe: %s\n", strerror(errno));
	slp->sent = 1; /* we sent a request, read the response later */

	lastfirstrec = slp->firstrec;

	if (++slp >= &slaves[SLAVES])
		slp = &slaves[0];

	/* Read results back from next slave */
	if (slp->sent) {
		if (atomic(read, slp->fd, (char *)&got, sizeof got)
		    != sizeof got) {
			perror("  DUMP: error reading command pipe in master");
			dumpabort(0);
		}
		slp->sent = 0;

		/* Check for end of tape */
		if (got < writesize) {
			msg("End of tape detected\n");

			/*
			 * Drain the results, don't care what the values were.
			 * If we read them here then trewind won't...
			 */
			for (i = 0; i < SLAVES; i++) {
				if (slaves[i].sent) {
					if (atomic(read, slaves[i].fd,
					    (char *)&got, sizeof got)
					    != sizeof got) {
						perror("  DUMP: error reading command pipe in master");
						dumpabort(0);
					}
					slaves[i].sent = 0;
				}
			}

			close_rewind();
			rollforward();
			return;
		}
	}

	blks = 0;
	if (spcl.c_type != TS_END) {
		for (i = 0; i < spcl.c_count; i++)
			if (spcl.c_addr[i] != 0)
				blks++;
	}
	slp->count = lastspclrec + blks + 1 - spcl.c_tapea;
	slp->tapea = spcl.c_tapea;
	slp->firstrec = lastfirstrec + ntrec;
	slp->inode = curino;
	nextblock = slp->tblock;
	trecno = 0;
	asize += tenths;
	blockswritten += ntrec;
	blocksthisvol += ntrec;
	if (!pipeout && (blocksperfile ?
	    (blocksthisvol >= blocksperfile) : (asize > tsize))) {
		close_rewind();
		startnewtape(0);
	}
	timeest();
}

void
trewind()
{
	int f;
	int got;

	for (f = 0; f < SLAVES; f++) {
		/*
		 * Drain the results, but unlike EOT we DO (or should) care 
		 * what the return values were, since if we detect EOT after 
		 * we think we've written the last blocks to the tape anyway, 
		 * we have to replay those blocks with rollforward.
		 *
		 * fixme: punt for now.  
		 */
		if (slaves[f].sent) {
			if (atomic(read, slaves[f].fd, (char *)&got, sizeof got)
			    != sizeof got) {
				perror("  DUMP: error reading command pipe in master");
				dumpabort(0);
			}
			slaves[f].sent = 0;
			if (got != writesize) {
				msg("EOT detected in last 2 tape records!\n");
				msg("Use a longer tape, decrease the size estimate\n");
				quit("or use no size estimate at all.\n");
			}
		}
		(void) close(slaves[f].fd);
	}
	while (wait((int *)NULL) >= 0)	/* wait for any signals from slaves */
		/* void */;

	if (pipeout)
		return;

	msg("Closing %s\n", tape);

#ifdef RDUMP
	if (host) {
		rmtclose();
		while (rmtopen(tape, 0) < 0)
			sleep(10);
		rmtclose();
		return;
	}
#endif
	(void) close(tapefd);
	while ((f = open(tape, 0)) < 0)
		sleep (10);
	(void) close(f);
}

void
close_rewind()
{
	trewind();
	if (nexttape)
		return;
	if (!nogripe) {
		msg("Change Volumes: Mount volume #%d\n", tapeno+1);
		broadcast("CHANGE DUMP VOLUMES!\7\7\n");
	}
	while (!query("Is the new volume mounted and ready to go?"))
		if (query("Do you want to abort?")) {
			dumpabort(0);
			/*NOTREACHED*/
		}
}

void
rollforward()
{
	register struct req *p, *q, *prev;
	register struct slave *tslp;
	int i, size, savedtapea, got;
	union u_spcl *ntb, *otb;
	tslp = &slaves[SLAVES];
	ntb = (union u_spcl *)tslp->tblock[1];

	/*
	 * Each of the N slaves should have requests that need to 
	 * be replayed on the next tape.  Use the extra slave buffers 
	 * (slaves[SLAVES]) to construct request lists to be sent to 
	 * each slave in turn.
	 */
	for (i = 0; i < SLAVES; i++) {
		q = &tslp->req[1];
		otb = (union u_spcl *)slp->tblock;

		/*
		 * For each request in the current slave, copy it to tslp. 
		 */

		prev = NULL;
		for (p = slp->req; p->count > 0; p += p->count) {
			*q = *p;
			if (p->dblk == 0)
				*ntb++ = *otb++; /* copy the datablock also */
			prev = q;
			q += q->count;
		}
		if (prev == NULL)
			quit("rollforward: protocol botch");
		if (prev->dblk != 0)
			prev->count -= 1;
		else
			ntb--;
		q -= 1;
		q->count = 0;
		q = &tslp->req[0];
		if (i == 0) {
			q->dblk = 0;
			q->count = 1;
			trecno = 0;
			nextblock = tslp->tblock;
			savedtapea = spcl.c_tapea;
			spcl.c_tapea = slp->tapea;