xref: /src/sys/kern/subr_disk.c

/*	$NetBSD: subr_disk.c,v 1.29.6.1 2001/08/24 00:11:35 nathanw Exp $	*/

/*-
 * Copyright (c) 1996, 1997, 1999, 2000 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
 * NASA Ames Research Center.
 *
 * 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 NetBSD
 *	Foundation, Inc. and its contributors.
 * 4. Neither the name of The NetBSD Foundation 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
 */

/*
 * Copyright (c) 1982, 1986, 1988, 1993
 *	The Regents of the University of California.  All rights reserved.
 * (c) UNIX System Laboratories, Inc.
 * All or some portions of this file are derived from material licensed
 * to the University of California by American Telephone and Telegraph
 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
 * the permission of UNIX System Laboratories, Inc.
 *
 * 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.
 *
 *	@(#)ufs_disksubr.c	8.5 (Berkeley) 1/21/94
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/buf.h>
#include <sys/syslog.h>
#include <sys/time.h>
#include <sys/disklabel.h>
#include <sys/disk.h>

/*
 * A global list of all disks attached to the system.  May grow or
 * shrink over time.
 */
struct	disklist_head disklist;	/* TAILQ_HEAD */
int	disk_count;		/* number of drives in global disklist */

/*
 * Seek sort for disks.  We depend on the driver which calls us using b_resid
 * as the current cylinder number.
 *
 * The argument bufq is an I/O queue for the device, on which there are
 * actually two queues, sorted in ascending cylinder order.  The first
 * queue holds those requests which are positioned after the current
 * cylinder (in the first request); the second holds requests which came
 * in after their cylinder number was passed.  Thus we implement a one-way
 * scan, retracting after reaching the end of the drive to the first request
 * on the second queue, at which time it becomes the first queue.
 *
 * A one-way scan is natural because of the way UNIX read-ahead blocks are
 * allocated.
 *
 * This is further adjusted by any `barriers' which may exist in the queue.
 * The bufq points to the last such ordered request.
 */
void
disksort_cylinder(struct buf_queue *bufq, struct buf *bp)
{
	struct buf *bq, *nbq;

	/*
	 * If there are ordered requests on the queue, we must start
	 * the elevator sort after the last of these.
	 */
	if ((bq = bufq->bq_barrier) == NULL)
		bq = BUFQ_FIRST(bufq);

	/*
	 * If the queue is empty, of if it's an ordered request,
	 * it's easy; we just go on the end.
	 */
	if (bq == NULL || (bp->b_flags & B_ORDERED) != 0) {
		BUFQ_INSERT_TAIL(bufq, bp);
		return;
	}

	/*
	 * If we lie after the first (currently active) request, then we
	 * must locate the second request list and add ourselves to it.
	 */
	if (bp->b_cylinder < bq->b_cylinder ||
	    (bp->b_cylinder == bq->b_cylinder &&
	     bp->b_rawblkno < bq->b_rawblkno)) {
		while ((nbq = BUFQ_NEXT(bq)) != NULL) {
			/*
			 * Check for an ``inversion'' in the normally ascending
			 * cylinder numbers, indicating the start of the second
			 * request list.
			 */
			if (nbq->b_cylinder < bq->b_cylinder) {
				/*
				 * Search the second request list for the first
				 * request at a larger cylinder number.  We go
				 * before that; if there is no such request, we
				 * go at end.
				 */
				do {
					if (bp->b_cylinder < nbq->b_cylinder)
						goto insert;
					if (bp->b_cylinder == nbq->b_cylinder &&
					    bp->b_rawblkno < nbq->b_rawblkno)
						goto insert;
					bq = nbq;
				} while ((nbq = BUFQ_NEXT(bq)) != NULL);
				goto insert;		/* after last */
			}
			bq = BUFQ_NEXT(bq);
		}
		/*
		 * No inversions... we will go after the last, and
		 * be the first request in the second request list.
		 */
		goto insert;
	}
	/*
	 * Request is at/after the current request...
	 * sort in the first request list.
	 */
	while ((nbq = BUFQ_NEXT(bq)) != NULL) {
		/*
		 * We want to go after the current request if there is an
		 * inversion after it (i.e. it is the end of the first
		 * request list), or if the next request is a larger cylinder
		 * than our request.
		 */
		if (nbq->b_cylinder < bq->b_cylinder ||
		    bp->b_cylinder < nbq->b_cylinder ||
		    (bp->b_cylinder == nbq->b_cylinder &&
		     bp->b_rawblkno < nbq->b_rawblkno))
			goto insert;
		bq = nbq;
	}
	/*
	 * Neither a second list nor a larger request... we go at the end of
	 * the first list, which is the same as the end of the whole schebang.
	 */
insert:	BUFQ_INSERT_AFTER(bufq, bq, bp);
}

/*
 * Seek sort for disks.  This version sorts based on b_rawblkno, which
 * indicates the block number.
 *
 * As before, there are actually two queues, sorted in ascendening block
 * order.  The first queue holds those requests which are positioned after
 * the current block (in the first request); the second holds requests which
 * came in after their block number was passed.  Thus we implement a one-way
 * scan, retracting after reaching the end of the driver to the first request
 * on the second queue, at which time it becomes the first queue.
 *
 * A one-way scan is natural because of the way UNIX read-ahead blocks are
 * allocated.
 *
 * This is further adjusted by any `barriers' which may exist in the queue.
 * The bufq points to the last such ordered request.
 */
void
disksort_blkno(struct buf_queue *bufq, struct buf *bp)
{
	struct buf *bq, *nbq;

	/*
	 * If there are ordered requests on the queue, we must start
	 * the elevator sort after the last of these.
	 */
	if ((bq = bufq->bq_barrier) == NULL)
		bq = BUFQ_FIRST(bufq);

	/*
	 * If the queue is empty, or if it's an ordered request,
	 * it's easy; we just go on the end.
	 */
	if (bq == NULL || (bp->b_flags & B_ORDERED) != 0) {
		BUFQ_INSERT_TAIL(bufq, bp);
		return;
	}

	/*
	 * If we lie after the first (currently active) request, then we
	 * must locate the second request list and add ourselves to it.
	 */
	if (bp->b_rawblkno < bq->b_rawblkno) {
		while ((nbq = BUFQ_NEXT(bq)) != NULL) {
			/*
			 * Check for an ``inversion'' in the normally ascending
			 * block numbers, indicating the start of the second
			 * request list.
			 */
			if (nbq->b_rawblkno < bq->b_rawblkno) {
				/*
				 * Search the second request list for the first
				 * request at a larger block number.  We go
				 * after that; if there is no such request, we
				 * go at the end.
				 */
				do {
					if (bp->b_rawblkno < nbq->b_rawblkno)
						goto insert;
					bq = nbq;
				} while ((nbq = BUFQ_NEXT(bq)) != NULL);
				goto insert;		/* after last */
			}
			bq = BUFQ_NEXT(bq);
		}
		/*
		 * No inversions... we will go after the last, and
		 * be the first request in the second request list.
		 */
		goto insert;
	}
	/*
	 * Request is at/after the current request...
	 * sort in the first request list.
	 */
	while ((nbq = BUFQ_NEXT(bq)) != NULL) {
		/*
		 * We want to go after the current request if there is an
		 * inversion after it (i.e. it is the end of the first
		 * request list), or if the next request is a larger cylinder
		 * than our request.
		 */
		if (nbq->b_rawblkno < bq->b_rawblkno ||
		    bp->b_rawblkno < nbq->b_rawblkno)
			goto insert;
		bq = nbq;
	}
	/*
	 * Neither a second list nor a larger request... we go at the end of
	 * the first list, which is the same as the end of the whole schebang.
	 */
insert:	BUFQ_INSERT_AFTER(bufq, bq, bp);
}

/*
 * Seek non-sort for disks.  This version simply inserts requests at
 * the tail of the queue.
 */
void
disksort_tail(struct buf_queue *bufq, struct buf *bp)
{

	BUFQ_INSERT_TAIL(bufq, bp);
}

/*
 * Compute checksum for disk label.
 */
u_int
dkcksum(struct disklabel *lp)
{
	u_short *start, *end;
	u_short sum = 0;

	start = (u_short *)lp;
	end = (u_short *)&lp->d_partitions[lp->d_npartitions];
	while (start < end)
		sum ^= *start++;
	return (sum);
}

/*
 * Disk error is the preface to plaintive error messages
 * about failing disk transfers.  It prints messages of the form

hp0g: hard error reading fsbn 12345 of 12344-12347 (hp0 bn %d cn %d tn %d sn %d)

 * if the offset of the error in the transfer and a disk label
 * are both available.  blkdone should be -1 if the position of the error
 * is unknown; the disklabel pointer may be null from drivers that have not
 * been converted to use them.  The message is printed with printf
 * if pri is LOG_PRINTF, otherwise it uses log at the specified priority.
 * The message should be completed (with at least a newline) with printf
 * or addlog, respectively.  There is no trailing space.
 */
void
diskerr(struct buf *bp, char *dname, char *what, int pri, int blkdone,
    struct disklabel *lp)
{
	int unit = DISKUNIT(bp->b_dev), part = DISKPART(bp->b_dev);
	void (*pr)(const char *, ...);
	char partname = 'a' + part;
	int sn;

	if (pri != LOG_PRINTF) {
		static const char fmt[] = "";
		log(pri, fmt);
		pr = addlog;
	} else
		pr = printf;
	(*pr)("%s%d%c: %s %sing fsbn ", dname, unit, partname, what,
	    bp->b_flags & B_READ ? "read" : "writ");
	sn = bp->b_blkno;
	if (bp->b_bcount <= DEV_BSIZE)
		(*pr)("%d", sn);
	else {
		if (blkdone >= 0) {
			sn += blkdone;
			(*pr)("%d of ", sn);
		}
		(*pr)("%d-%d", bp->b_blkno,
		    bp->b_blkno + (bp->b_bcount - 1) / DEV_BSIZE);
	}
	if (lp && (blkdone >= 0 || bp->b_bcount <= lp->d_secsize)) {
		sn += lp->d_partitions[part].p_offset;
		(*pr)(" (%s%d bn %d; cn %d", dname, unit, sn,
		    sn / lp->d_secpercyl);
		sn %= lp->d_secpercyl;
		(*pr)(" tn %d sn %d)", sn / lp->d_nsectors, sn % lp->d_nsectors);
	}
}

/*
 * Initialize the disklist.  Called by main() before autoconfiguration.
 */
void
disk_init(void)
{

	TAILQ_INIT(&disklist);
	disk_count = 0;
}

/*
 * Searches the disklist for the disk corresponding to the
 * name provided.
 */
struct disk *
disk_find(char *name)
{
	struct disk *diskp;

	if ((name == NULL) || (disk_count <= 0))
		return (NULL);

	for (diskp = disklist.tqh_first; diskp != NULL;
	    diskp = diskp->dk_link.tqe_next)
		if (strcmp(diskp->dk_name, name) == 0)
			return (diskp);

	return (NULL);
}

/*
 * Attach a disk.
 */
void
disk_attach(struct disk *diskp)
{
	int s;

	/*
	 * Allocate and initialize the disklabel structures.  Note that
	 * it's not safe to sleep here, since we're probably going to be
	 * called during autoconfiguration.
	 */
	diskp->dk_label = malloc(sizeof(struct disklabel), M_DEVBUF, M_NOWAIT);
	diskp->dk_cpulabel = malloc(sizeof(struct cpu_disklabel), M_DEVBUF,
	    M_NOWAIT);
	if ((diskp->dk_label == NULL) || (diskp->dk_cpulabel == NULL))
		panic("disk_attach: can't allocate storage for disklabel");

	memset(diskp->dk_label, 0, sizeof(struct disklabel));
	memset(diskp->dk_cpulabel, 0, sizeof(struct cpu_disklabel));

	/*
	 * Set the attached timestamp.
	 */
	s = splclock();
	diskp->dk_attachtime = mono_time;
	splx(s);

	/*
	 * Link into the disklist.
	 */
	TAILQ_INSERT_TAIL(&disklist, diskp, dk_link);
	++disk_count;
}

/*
 * Detach a disk.
 */
void
disk_detach(struct disk *diskp)
{

	/*
	 * Remove from the disklist.
	 */
	if (--disk_count < 0)
		panic("disk_detach: disk_count < 0");
	TAILQ_REMOVE(&disklist, diskp, dk_link);

	/*
	 * Free the space used by the disklabel structures.
	 */
	free(diskp->dk_label, M_DEVBUF);
	free(diskp->dk_cpulabel, M_DEVBUF);
}

/*
 * Increment a disk's busy counter.  If the counter is going from
 * 0 to 1, set the timestamp.
 */
void
disk_busy(struct disk *diskp)
{
	int s;

	/*
	 * XXX We'd like to use something as accurate as microtime(),
	 * but that doesn't depend on the system TOD clock.
	 */
	if (diskp->dk_busy++ == 0) {
		s = splclock();
		diskp->dk_timestamp = mono_time;
		splx(s);
	}
}

/*
 * Decrement a disk's busy counter, increment the byte count, total busy
 * time, and reset the timestamp.
 */
void
disk_unbusy(struct disk *diskp, long bcount)
{
	int s;
	struct timeval dv_time, diff_time;

	if (diskp->dk_busy-- == 0) {
		printf("%s: dk_busy < 0\n", diskp->dk_name);
		panic("disk_unbusy");
	}

	s = splclock();
	dv_time = mono_time;
	splx(s);

	timersub(&dv_time, &diskp->dk_timestamp, &diff_time);
	timeradd(&diskp->dk_time, &diff_time, &diskp->dk_time);

	diskp->dk_timestamp = dv_time;
	if (bcount > 0) {
		diskp->dk_bytes += bcount;
		diskp->dk_xfer++;
	}
}

/*
 * Reset the metrics counters on the given disk.  Note that we cannot
 * reset the busy counter, as it may case a panic in disk_unbusy().
 * We also must avoid playing with the timestamp information, as it
 * may skew any pending transfer results.
 */
void
disk_resetstat(struct disk *diskp)
{
	int s = splbio(), t;

	diskp->dk_xfer = 0;
	diskp->dk_bytes = 0;

	t = splclock();
	diskp->dk_attachtime = mono_time;
	splx(t);

	timerclear(&diskp->dk_time);

	splx(s);
}