File:  [DragonFly] / src / sys / dev / disk / ccd / ccd.c
Revision 1.16: download - view: text, annotated - select for diffs
Wed May 19 22:52:41 2004 UTC (10 years, 4 months ago) by dillon
Branches: MAIN
CVS tags: HEAD, DragonFly_Snap29Sep2004, DragonFly_Snap13Sep2004, DragonFly_1_0_REL, DragonFly_1_0_RC1, DragonFly_1_0A_REL
Device layer rollup commit.

* cdevsw_add() is now required.  cdevsw_add() and cdevsw_remove() may specify
  a mask/match indicating the range of supported minor numbers.  Multiple
  cdevsw_add()'s using the same major number, but distinctly different
  ranges, may be issued.  All devices that failed to call cdevsw_add() before
  now do.

* cdevsw_remove() now automatically marks all devices within its supported
  range as being destroyed.

* vnode->v_rdev is no longer resolved when the vnode is created.  Instead,
  only v_udev (a newly added field) is resolved.  v_rdev is resolved when
  the vnode is opened and cleared on the last close.

* A great deal of code was making rather dubious assumptions with regards
  to the validity of devices associated with vnodes, primarily due to
  the persistence of a device structure due to being indexed by (major, minor)
  instead of by (cdevsw, major, minor).  In particular, if you run a program
  which connects to a USB device and then you pull the USB device and plug
  it back in, the vnode subsystem will continue to believe that the device
  is open when, in fact, it isn't (because it was destroyed and recreated).

  In particular, note that all the VFS mount procedures now check devices
  via v_udev instead of v_rdev prior to calling VOP_OPEN(), since v_rdev
  is NULL prior to the first open.

* The disk layer's device interaction has been rewritten.  The disk layer
  (i.e. the slice and disklabel management layer) no longer overloads
  its data onto the device structure representing the underlying physical
  disk.  Instead, the disk layer uses the new cdevsw_add() functionality
  to register its own cdevsw using the underlying device's major number,
  and simply does NOT register the underlying device's cdevsw.  No
  confusion is created because the device hash is now based on
  (cdevsw,major,minor) rather then (major,minor).

  NOTE: This also means that underlying raw disk devices may use the entire
  device minor number instead of having to reserve the bits used by the disk
  layer, and also means that can we (theoretically) stack a fully
  disklabel-supported 'disk' on top of any block device.

* The new reference counting scheme prevents this by associating a device
  with a cdevsw and disconnecting the device from its cdevsw when the cdevsw
  is removed.  Additionally, all udev2dev() lookups run through the cdevsw
  mask/match and only successfully find devices still associated with an
  active cdevsw.

* Major work on MFS:  MFS no longer shortcuts vnode and device creation.  It
  now creates a real vnode and a real device and implements real open and
  close VOPs.  Additionally, due to the disk layer changes, MFS is no longer
  limited to 255 mounts.  The new limit is 16 million.  Since MFS creates a
  real device node, mount_mfs will now create a real /dev/mfs<PID> device
  that can be read from userland (e.g. so you can dump an MFS filesystem).

* BUF AND DEVICE STRATEGY changes.  The struct buf contains a b_dev field.
  In order to properly handle stacked devices we now require that the b_dev
  field be initialized before the device strategy routine is called.  This
  required some additional work in various VFS implementations.  To enforce
  this requirement, biodone() now sets b_dev to NODEV.  The new disk layer
  will adjust b_dev before forwarding a request to the actual physical
  device.

* A bug in the ISO CD boot sequence which resulted in a panic has been fixed.

Testing by: lots of people, but David Rhodus found the most aggregious bugs.

/* $FreeBSD: src/sys/dev/ccd/ccd.c,v 1.73.2.1 2001/09/11 09:49:52 kris Exp $ */
/* $DragonFly: src/sys/dev/disk/ccd/ccd.c,v 1.16 2004/05/19 22:52:41 dillon Exp $ */

/*	$NetBSD: ccd.c,v 1.22 1995/12/08 19:13:26 thorpej Exp $	*/

/*
 * Copyright (c) 1995 Jason R. Thorpe.
 * 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 for the NetBSD Project
 *	by Jason R. Thorpe.
 * 4. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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) 1988 University of Utah.
 * Copyright (c) 1990, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * the Systems Programming Group of the University of Utah Computer
 * Science Department.
 *
 * 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.
 *
 * from: Utah $Hdr: cd.c 1.6 90/11/28$
 *
 *	@(#)cd.c	8.2 (Berkeley) 11/16/93
 */

/*
 * "Concatenated" disk driver.
 *
 * Dynamic configuration and disklabel support by:
 *	Jason R. Thorpe <thorpej@nas.nasa.gov>
 *	Numerical Aerodynamic Simulation Facility
 *	Mail Stop 258-6
 *	NASA Ames Research Center
 *	Moffett Field, CA 94035
 */

#include "use_ccd.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/proc.h>
#include <sys/buf.h>
#include <sys/malloc.h>
#include <sys/namei.h>
#include <sys/conf.h>
#include <sys/stat.h>
#include <sys/sysctl.h>
#include <sys/disklabel.h>
#include <vfs/ufs/fs.h> 
#include <sys/devicestat.h>
#include <sys/fcntl.h>
#include <sys/vnode.h>
#include <sys/buf2.h>

#include <sys/ccdvar.h>

#include <vm/vm_zone.h>

#if defined(CCDDEBUG) && !defined(DEBUG)
#define DEBUG
#endif

#ifdef DEBUG
#define CCDB_FOLLOW	0x01
#define CCDB_INIT	0x02
#define CCDB_IO		0x04
#define CCDB_LABEL	0x08
#define CCDB_VNODE	0x10
static int ccddebug = CCDB_FOLLOW | CCDB_INIT | CCDB_IO | CCDB_LABEL |
    CCDB_VNODE;
SYSCTL_INT(_debug, OID_AUTO, ccddebug, CTLFLAG_RW, &ccddebug, 0, "");
#undef DEBUG
#endif

#define	ccdunit(x)	dkunit(x)
#define ccdpart(x)	dkpart(x)

/*
   This is how mirroring works (only writes are special):

   When initiating a write, ccdbuffer() returns two "struct ccdbuf *"s
   linked together by the cb_mirror field.  "cb_pflags &
   CCDPF_MIRROR_DONE" is set to 0 on both of them.

   When a component returns to ccdiodone(), it checks if "cb_pflags &
   CCDPF_MIRROR_DONE" is set or not.  If not, it sets the partner's
   flag and returns.  If it is, it means its partner has already
   returned, so it will go to the regular cleanup.

 */

struct ccdbuf {
	struct buf	cb_buf;		/* new I/O buf */
	struct buf	*cb_obp;	/* ptr. to original I/O buf */
	struct ccdbuf	*cb_freenext;	/* free list link */
	int		cb_unit;	/* target unit */
	int		cb_comp;	/* target component */
	int		cb_pflags;	/* mirror/parity status flag */
	struct ccdbuf	*cb_mirror;	/* mirror counterpart */
};

/* bits in cb_pflags */
#define CCDPF_MIRROR_DONE 1	/* if set, mirror counterpart is done */

#define CCDLABELDEV(dev)	\
	(make_sub_dev(dev, dkmakeminor(ccdunit((dev)), 0, RAW_PART)))

static d_open_t ccdopen;
static d_close_t ccdclose;
static d_strategy_t ccdstrategy;
static d_ioctl_t ccdioctl;
static d_dump_t ccddump;
static d_psize_t ccdsize;

#define NCCDFREEHIWAT	16

#define CDEV_MAJOR 74

static struct cdevsw ccd_cdevsw = {
	/* name */	"ccd",
	/* maj */	CDEV_MAJOR,
	/* flags */	D_DISK,
	/* port */      NULL,
	/* clone */	NULL,
 
	/* open */	ccdopen,
	/* close */	ccdclose,
	/* read */	physread,
	/* write */	physwrite,
	/* ioctl */	ccdioctl,
	/* poll */	nopoll,
	/* mmap */	nommap,
	/* strategy */	ccdstrategy,
	/* dump */	ccddump,
	/* psize */	ccdsize
};

/* called during module initialization */
static	void ccdattach (void);
static	int ccd_modevent (module_t, int, void *);

/* called by biodone() at interrupt time */
static	void ccdiodone (struct ccdbuf *cbp);

static	void ccdstart (struct ccd_softc *, struct buf *);
static	void ccdinterleave (struct ccd_softc *, int);
static	void ccdintr (struct ccd_softc *, struct buf *);
static	int ccdinit (struct ccddevice *, char **, struct thread *);
static	int ccdlookup (char *, struct thread *td, struct vnode **);
static	void ccdbuffer (struct ccdbuf **ret, struct ccd_softc *,
		struct buf *, daddr_t, caddr_t, long);
static	void ccdgetdisklabel (dev_t);
static	void ccdmakedisklabel (struct ccd_softc *);
static	int ccdlock (struct ccd_softc *);
static	void ccdunlock (struct ccd_softc *);

#ifdef DEBUG
static	void printiinfo (struct ccdiinfo *);
#endif

/* Non-private for the benefit of libkvm. */
struct	ccd_softc *ccd_softc;
struct	ccddevice *ccddevs;
struct	ccdbuf *ccdfreebufs;
static	int numccdfreebufs;
static	int numccd = 0;

/*
 * getccdbuf() -	Allocate and zero a ccd buffer.
 *
 *	This routine is called at splbio().
 */

static __inline
struct ccdbuf *
getccdbuf(struct ccdbuf *cpy)
{
	struct ccdbuf *cbp;

	/*
	 * Allocate from freelist or malloc as necessary
	 */
	if ((cbp = ccdfreebufs) != NULL) {
		ccdfreebufs = cbp->cb_freenext;
		--numccdfreebufs;
	} else {
		cbp = malloc(sizeof(struct ccdbuf), M_DEVBUF, M_WAITOK);
	}

	/*
	 * Used by mirroring code
	 */
	if (cpy)
		bcopy(cpy, cbp, sizeof(struct ccdbuf));
	else
		bzero(cbp, sizeof(struct ccdbuf));

	/*
	 * independant struct buf initialization
	 */
	LIST_INIT(&cbp->cb_buf.b_dep);
	BUF_LOCKINIT(&cbp->cb_buf);
	BUF_LOCK(&cbp->cb_buf, LK_EXCLUSIVE);
	BUF_KERNPROC(&cbp->cb_buf);

	return(cbp);
}

/*
 * putccdbuf() -	Free a ccd buffer.
 *
 *	This routine is called at splbio().
 */

static __inline
void
putccdbuf(struct ccdbuf *cbp)
{
	BUF_UNLOCK(&cbp->cb_buf);
	BUF_LOCKFREE(&cbp->cb_buf);

	if (numccdfreebufs < NCCDFREEHIWAT) {
		cbp->cb_freenext = ccdfreebufs;
		ccdfreebufs = cbp;
		++numccdfreebufs;
	} else {
		free((caddr_t)cbp, M_DEVBUF);
	}
}


/*
 * Number of blocks to untouched in front of a component partition.
 * This is to avoid violating its disklabel area when it starts at the
 * beginning of the slice.
 */
#if !defined(CCD_OFFSET)
#define CCD_OFFSET 16
#endif

/*
 * Called by main() during pseudo-device attachment.  All we need
 * to do is allocate enough space for devices to be configured later, and
 * add devsw entries.
 */
static void
ccdattach()
{
	int i;
	int num = NCCD;

	if (num > 1)
		printf("ccd0-%d: Concatenated disk drivers\n", num-1);
	else
		printf("ccd0: Concatenated disk driver\n");

	ccd_softc = malloc(num * sizeof(struct ccd_softc), M_DEVBUF, 
			    M_WAITOK | M_ZERO);
	ccddevs = malloc(num * sizeof(struct ccddevice), M_DEVBUF,
			    M_WAITOK | M_ZERO);
	numccd = num;

	cdevsw_add(&ccd_cdevsw, 0, 0);
	/* XXX: is this necessary? */
	for (i = 0; i < numccd; ++i)
		ccddevs[i].ccd_dk = -1;
}

static int
ccd_modevent(mod, type, data)
	module_t mod;
	int type;
	void *data;
{
	int error = 0;

	switch (type) {
	case MOD_LOAD:
		ccdattach();
		break;

	case MOD_UNLOAD:
		printf("ccd0: Unload not supported!\n");
		error = EOPNOTSUPP;
		break;

	default:	/* MOD_SHUTDOWN etc */
		break;
	}
	return (error);
}

DEV_MODULE(ccd, ccd_modevent, NULL);

static int
ccdinit(struct ccddevice *ccd, char **cpaths, struct thread *td)
{
	struct ccd_softc *cs = &ccd_softc[ccd->ccd_unit];
	struct ccdcinfo *ci = NULL;	/* XXX */
	size_t size;
	int ix;
	struct vnode *vp;
	size_t minsize;
	int maxsecsize;
	struct partinfo dpart;
	struct ccdgeom *ccg = &cs->sc_geom;
	char tmppath[MAXPATHLEN];
	int error = 0;
	struct ucred *cred;

	KKASSERT(td->td_proc);
	cred = td->td_proc->p_ucred;

#ifdef DEBUG
	if (ccddebug & (CCDB_FOLLOW|CCDB_INIT))
		printf("ccdinit: unit %d\n", ccd->ccd_unit);
#endif

	cs->sc_size = 0;
	cs->sc_ileave = ccd->ccd_interleave;
	cs->sc_nccdisks = ccd->ccd_ndev;

	/* Allocate space for the component info. */
	cs->sc_cinfo = malloc(cs->sc_nccdisks * sizeof(struct ccdcinfo),
	    M_DEVBUF, M_WAITOK);

	/*
	 * Verify that each component piece exists and record
	 * relevant information about it.
	 */
	maxsecsize = 0;
	minsize = 0;
	for (ix = 0; ix < cs->sc_nccdisks; ix++) {
		vp = ccd->ccd_vpp[ix];
		ci = &cs->sc_cinfo[ix];
		ci->ci_vp = vp;

		/*
		 * Copy in the pathname of the component.
		 */
		bzero(tmppath, sizeof(tmppath));	/* sanity */
		if ((error = copyinstr(cpaths[ix], tmppath,
		    MAXPATHLEN, &ci->ci_pathlen)) != 0) {
#ifdef DEBUG
			if (ccddebug & (CCDB_FOLLOW|CCDB_INIT))
				printf("ccd%d: can't copy path, error = %d\n",
				    ccd->ccd_unit, error);
#endif
			goto fail;
		}
		ci->ci_path = malloc(ci->ci_pathlen, M_DEVBUF, M_WAITOK);
		bcopy(tmppath, ci->ci_path, ci->ci_pathlen);

		ci->ci_dev = vn_todev(vp);

		/*
		 * Get partition information for the component.
		 */
		if ((error = VOP_IOCTL(vp, DIOCGPART, (caddr_t)&dpart,
		    FREAD, cred, td)) != 0) {
#ifdef DEBUG
			if (ccddebug & (CCDB_FOLLOW|CCDB_INIT))
				 printf("ccd%d: %s: ioctl failed, error = %d\n",
				     ccd->ccd_unit, ci->ci_path, error);
#endif
			goto fail;
		}
		if (dpart.part->p_fstype == FS_BSDFFS) {
			maxsecsize =
			    ((dpart.disklab->d_secsize > maxsecsize) ?
			    dpart.disklab->d_secsize : maxsecsize);
			size = dpart.part->p_size - CCD_OFFSET;
		} else {
#ifdef DEBUG
			if (ccddebug & (CCDB_FOLLOW|CCDB_INIT))
				printf("ccd%d: %s: incorrect partition type\n",
				    ccd->ccd_unit, ci->ci_path);
#endif
			error = EFTYPE;
			goto fail;
		}

		/*
		 * Calculate the size, truncating to an interleave
		 * boundary if necessary.
		 */

		if (cs->sc_ileave > 1)
			size -= size % cs->sc_ileave;

		if (size == 0) {
#ifdef DEBUG
			if (ccddebug & (CCDB_FOLLOW|CCDB_INIT))
				printf("ccd%d: %s: size == 0\n",
				    ccd->ccd_unit, ci->ci_path);
#endif
			error = ENODEV;
			goto fail;
		}

		if (minsize == 0 || size < minsize)
			minsize = size;
		ci->ci_size = size;
		cs->sc_size += size;
	}

	/*
	 * Don't allow the interleave to be smaller than
	 * the biggest component sector.
	 */
	if ((cs->sc_ileave > 0) &&
	    (cs->sc_ileave < (maxsecsize / DEV_BSIZE))) {
#ifdef DEBUG
		if (ccddebug & (CCDB_FOLLOW|CCDB_INIT))
			printf("ccd%d: interleave must be at least %d\n",
			    ccd->ccd_unit, (maxsecsize / DEV_BSIZE));
#endif
		error = EINVAL;
		goto fail;
	}

	/*
	 * If uniform interleave is desired set all sizes to that of
	 * the smallest component.  This will guarentee that a single
	 * interleave table is generated.
	 *
	 * Lost space must be taken into account when calculating the
	 * overall size.  Half the space is lost when CCDF_MIRROR is
	 * specified.  One disk is lost when CCDF_PARITY is specified.
	 */
	if (ccd->ccd_flags & CCDF_UNIFORM) {
		for (ci = cs->sc_cinfo;
		     ci < &cs->sc_cinfo[cs->sc_nccdisks]; ci++) {
			ci->ci_size = minsize;
		}
		if (ccd->ccd_flags & CCDF_MIRROR) {
			/*
			 * Check to see if an even number of components
			 * have been specified.  The interleave must also
			 * be non-zero in order for us to be able to 
			 * guarentee the topology.
			 */
			if (cs->sc_nccdisks % 2) {
				printf("ccd%d: mirroring requires an even number of disks\n", ccd->ccd_unit );
				error = EINVAL;
				goto fail;
			}
			if (cs->sc_ileave == 0) {
				printf("ccd%d: an interleave must be specified when mirroring\n", ccd->ccd_unit);
				error = EINVAL;
				goto fail;
			}
			cs->sc_size = (cs->sc_nccdisks/2) * minsize;
		} else if (ccd->ccd_flags & CCDF_PARITY) {
			cs->sc_size = (cs->sc_nccdisks-1) * minsize;
		} else {
			if (cs->sc_ileave == 0) {
				printf("ccd%d: an interleave must be specified when using parity\n", ccd->ccd_unit);
				error = EINVAL;
				goto fail;
			}
			cs->sc_size = cs->sc_nccdisks * minsize;
		}
	}

	/*
	 * Construct the interleave table.
	 */
	ccdinterleave(cs, ccd->ccd_unit);

	/*
	 * Create pseudo-geometry based on 1MB cylinders.  It's
	 * pretty close.
	 */
	ccg->ccg_secsize = maxsecsize;
	ccg->ccg_ntracks = 1;
	ccg->ccg_nsectors = 1024 * 1024 / ccg->ccg_secsize;
	ccg->ccg_ncylinders = cs->sc_size / ccg->ccg_nsectors;

	/*
	 * Add an devstat entry for this device.
	 */
	devstat_add_entry(&cs->device_stats, "ccd", ccd->ccd_unit,
			  ccg->ccg_secsize, DEVSTAT_ALL_SUPPORTED,
			  DEVSTAT_TYPE_STORARRAY |DEVSTAT_TYPE_IF_OTHER,
			  DEVSTAT_PRIORITY_ARRAY);

	cs->sc_flags |= CCDF_INITED;
	cs->sc_cflags = ccd->ccd_flags;	/* So we can find out later... */
	cs->sc_unit = ccd->ccd_unit;
	return (0);
fail:
	while (ci > cs->sc_cinfo) {
		ci--;
		free(ci->ci_path, M_DEVBUF);
	}
	free(cs->sc_cinfo, M_DEVBUF);
	return (error);
}

static void
ccdinterleave(cs, unit)
	struct ccd_softc *cs;
	int unit;
{
	struct ccdcinfo *ci, *smallci;
	struct ccdiinfo *ii;
	daddr_t bn, lbn;
	int ix;
	u_long size;

#ifdef DEBUG
	if (ccddebug & CCDB_INIT)
		printf("ccdinterleave(%x): ileave %d\n", cs, cs->sc_ileave);
#endif

	/*
	 * Allocate an interleave table.  The worst case occurs when each
	 * of N disks is of a different size, resulting in N interleave
	 * tables.
	 *
	 * Chances are this is too big, but we don't care.
	 */
	size = (cs->sc_nccdisks + 1) * sizeof(struct ccdiinfo);
	cs->sc_itable = (struct ccdiinfo *)malloc(size, M_DEVBUF, M_WAITOK);
	bzero((caddr_t)cs->sc_itable, size);

	/*
	 * Trivial case: no interleave (actually interleave of disk size).
	 * Each table entry represents a single component in its entirety.
	 *
	 * An interleave of 0 may not be used with a mirror or parity setup.
	 */
	if (cs->sc_ileave == 0) {
		bn = 0;
		ii = cs->sc_itable;

		for (ix = 0; ix < cs->sc_nccdisks; ix++) {
			/* Allocate space for ii_index. */
			ii->ii_index = malloc(sizeof(int), M_DEVBUF, M_WAITOK);
			ii->ii_ndisk = 1;
			ii->ii_startblk = bn;
			ii->ii_startoff = 0;
			ii->ii_index[0] = ix;
			bn += cs->sc_cinfo[ix].ci_size;
			ii++;
		}
		ii->ii_ndisk = 0;
#ifdef DEBUG
		if (ccddebug & CCDB_INIT)
			printiinfo(cs->sc_itable);
#endif
		return;
	}

	/*
	 * The following isn't fast or pretty; it doesn't have to be.
	 */
	size = 0;
	bn = lbn = 0;
	for (ii = cs->sc_itable; ; ii++) {
		/*
		 * Allocate space for ii_index.  We might allocate more then
		 * we use.
		 */
		ii->ii_index = malloc((sizeof(int) * cs->sc_nccdisks),
		    M_DEVBUF, M_WAITOK);

		/*
		 * Locate the smallest of the remaining components
		 */
		smallci = NULL;
		for (ci = cs->sc_cinfo; ci < &cs->sc_cinfo[cs->sc_nccdisks]; 
		    ci++) {
			if (ci->ci_size > size &&
			    (smallci == NULL ||
			     ci->ci_size < smallci->ci_size)) {
				smallci = ci;
			}
		}

		/*
		 * Nobody left, all done
		 */
		if (smallci == NULL) {
			ii->ii_ndisk = 0;
			break;
		}

		/*
		 * Record starting logical block using an sc_ileave blocksize.
		 */
		ii->ii_startblk = bn / cs->sc_ileave;

		/*
		 * Record starting comopnent block using an sc_ileave 
		 * blocksize.  This value is relative to the beginning of
		 * a component disk.
		 */
		ii->ii_startoff = lbn;

		/*
		 * Determine how many disks take part in this interleave
		 * and record their indices.
		 */
		ix = 0;
		for (ci = cs->sc_cinfo; 
		    ci < &cs->sc_cinfo[cs->sc_nccdisks]; ci++) {
			if (ci->ci_size >= smallci->ci_size) {
				ii->ii_index[ix++] = ci - cs->sc_cinfo;
			}
		}
		ii->ii_ndisk = ix;
		bn += ix * (smallci->ci_size - size);
		lbn = smallci->ci_size / cs->sc_ileave;
		size = smallci->ci_size;
	}
#ifdef DEBUG
	if (ccddebug & CCDB_INIT)
		printiinfo(cs->sc_itable);
#endif
}

/* ARGSUSED */
static int
ccdopen(dev_t dev, int flags, int fmt, d_thread_t *td)
{
	int unit = ccdunit(dev);
	struct ccd_softc *cs;
	struct disklabel *lp;
	int error = 0, part, pmask;

#ifdef DEBUG
	if (ccddebug & CCDB_FOLLOW)
		printf("ccdopen(%x, %x)\n", dev, flags);
#endif
	if (unit >= numccd)
		return (ENXIO);
	cs = &ccd_softc[unit];

	if ((error = ccdlock(cs)) != 0)
		return (error);

	lp = &cs->sc_label;

	part = ccdpart(dev);
	pmask = (1 << part);

	/*
	 * If we're initialized, check to see if there are any other
	 * open partitions.  If not, then it's safe to update
	 * the in-core disklabel.
	 */
	if ((cs->sc_flags & CCDF_INITED) && (cs->sc_openmask == 0))
		ccdgetdisklabel(dev);

	/* Check that the partition exists. */
	if (part != RAW_PART && ((part >= lp->d_npartitions) ||
	    (lp->d_partitions[part].p_fstype == FS_UNUSED))) {
		error = ENXIO;
		goto done;
	}

	cs->sc_openmask |= pmask;
 done:
	ccdunlock(cs);
	return (0);
}

/* ARGSUSED */
static int
ccdclose(dev_t dev, int flags, int fmt, d_thread_t *td)
{
	int unit = ccdunit(dev);
	struct ccd_softc *cs;
	int error = 0, part;

#ifdef DEBUG
	if (ccddebug & CCDB_FOLLOW)
		printf("ccdclose(%x, %x)\n", dev, flags);
#endif

	if (unit >= numccd)
		return (ENXIO);
	cs = &ccd_softc[unit];

	if ((error = ccdlock(cs)) != 0)
		return (error);

	part = ccdpart(dev);

	/* ...that much closer to allowing unconfiguration... */
	cs->sc_openmask &= ~(1 << part);
	ccdunlock(cs);
	return (0);
}

static void
ccdstrategy(bp)
	struct buf *bp;
{
	int unit = ccdunit(bp->b_dev);
	struct ccd_softc *cs = &ccd_softc[unit];
	int s;
	int wlabel;
	struct disklabel *lp;

#ifdef DEBUG
	if (ccddebug & CCDB_FOLLOW)
		printf("ccdstrategy(%x): unit %d\n", bp, unit);
#endif
	if ((cs->sc_flags & CCDF_INITED) == 0) {
		bp->b_error = ENXIO;
		bp->b_flags |= B_ERROR;
		goto done;
	}

	/* If it's a nil transfer, wake up the top half now. */
	if (bp->b_bcount == 0)
		goto done;

	lp = &cs->sc_label;

	/*
	 * Do bounds checking and adjust transfer.  If there's an
	 * error, the bounds check will flag that for us.
	 */
	wlabel = cs->sc_flags & (CCDF_WLABEL|CCDF_LABELLING);
	if (ccdpart(bp->b_dev) != RAW_PART) {
		if (bounds_check_with_label(bp, lp, wlabel) <= 0)
			goto done;
	} else {
		int pbn;        /* in sc_secsize chunks */
		long sz;        /* in sc_secsize chunks */

		pbn = bp->b_blkno / (cs->sc_geom.ccg_secsize / DEV_BSIZE);
		sz = howmany(bp->b_bcount, cs->sc_geom.ccg_secsize);

		/*
		 * If out of bounds return an error. If at the EOF point,
		 * simply read or write less.
		 */

		if (pbn < 0 || pbn >= cs->sc_size) {
			bp->b_resid = bp->b_bcount;
			if (pbn != cs->sc_size) {
				bp->b_error = EINVAL;
				bp->b_flags |= B_ERROR | B_INVAL;
			}
			goto done;
		}

		/*
		 * If the request crosses EOF, truncate the request.
		 */
		if (pbn + sz > cs->sc_size) {
			bp->b_bcount = (cs->sc_size - pbn) * 
			    cs->sc_geom.ccg_secsize;
		}
	}

	bp->b_resid = bp->b_bcount;

	/*
	 * "Start" the unit.
	 */
	s = splbio();
	ccdstart(cs, bp);
	splx(s);
	return;
done:
	biodone(bp);
}

static void
ccdstart(cs, bp)
	struct ccd_softc *cs;
	struct buf *bp;
{
	long bcount, rcount;
	struct ccdbuf *cbp[4];
	/* XXX! : 2 reads and 2 writes for RAID 4/5 */
	caddr_t addr;
	daddr_t bn;
	struct partition *pp;

#ifdef DEBUG
	if (ccddebug & CCDB_FOLLOW)
		printf("ccdstart(%x, %x)\n", cs, bp);
#endif

	/* Record the transaction start  */
	devstat_start_transaction(&cs->device_stats);

	/*
	 * Translate the partition-relative block number to an absolute.
	 */
	bn = bp->b_blkno;
	if (ccdpart(bp->b_dev) != RAW_PART) {
		pp = &cs->sc_label.d_partitions[ccdpart(bp->b_dev)];
		bn += pp->p_offset;
	}

	/*
	 * Allocate component buffers and fire off the requests
	 */
	addr = bp->b_data;
	for (bcount = bp->b_bcount; bcount > 0; bcount -= rcount) {
		ccdbuffer(cbp, cs, bp, bn, addr, bcount);
		rcount = cbp[0]->cb_buf.b_bcount;

		if (cs->sc_cflags & CCDF_MIRROR) {
			/*
			 * Mirroring.  Writes go to both disks, reads are
			 * taken from whichever disk seems most appropriate.
			 *
			 * We attempt to localize reads to the disk whos arm
			 * is nearest the read request.  We ignore seeks due
			 * to writes when making this determination and we
			 * also try to avoid hogging.
			 */
			if ((cbp[0]->cb_buf.b_flags & B_READ) == 0) {
				cbp[0]->cb_buf.b_vp->v_numoutput++;
				cbp[1]->cb_buf.b_vp->v_numoutput++;
				VOP_STRATEGY(cbp[0]->cb_buf.b_vp, 
				    &cbp[0]->cb_buf);
				VOP_STRATEGY(cbp[1]->cb_buf.b_vp, 
				    &cbp[1]->cb_buf);
			} else {
				int pick = cs->sc_pick;
				daddr_t range = cs->sc_size / 16;

				if (bn < cs->sc_blk[pick] - range ||
				    bn > cs->sc_blk[pick] + range
				) {
					cs->sc_pick = pick = 1 - pick;
				}
				cs->sc_blk[pick] = bn + btodb(rcount);
				VOP_STRATEGY(cbp[pick]->cb_buf.b_vp, 
				    &cbp[pick]->cb_buf);
			}
		} else {
			/*
			 * Not mirroring
			 */
			if ((cbp[0]->cb_buf.b_flags & B_READ) == 0)
				cbp[0]->cb_buf.b_vp->v_numoutput++;
			VOP_STRATEGY(cbp[0]->cb_buf.b_vp, &cbp[0]->cb_buf);
		}
		bn += btodb(rcount);
		addr += rcount;
	}
}

/*
 * Build a component buffer header.
 */
static void
ccdbuffer(cb, cs, bp, bn, addr, bcount)
	struct ccdbuf **cb;
	struct ccd_softc *cs;
	struct buf *bp;
	daddr_t bn;
	caddr_t addr;
	long bcount;
{
	struct ccdcinfo *ci, *ci2 = NULL;	/* XXX */
	struct ccdbuf *cbp;
	daddr_t cbn, cboff;
	off_t cbc;

#ifdef DEBUG
	if (ccddebug & CCDB_IO)
		printf("ccdbuffer(%x, %x, %d, %x, %d)\n",
		       cs, bp, bn, addr, bcount);
#endif
	/*
	 * Determine which component bn falls in.
	 */
	cbn = bn;
	cboff = 0;

	if (cs->sc_ileave == 0) {
		/*
		 * Serially concatenated and neither a mirror nor a parity
		 * config.  This is a special case.
		 */
		daddr_t sblk;

		sblk = 0;
		for (ci = cs->sc_cinfo; cbn >= sblk + ci->ci_size; ci++)
			sblk += ci->ci_size;
		cbn -= sblk;
	} else {
		struct ccdiinfo *ii;
		int ccdisk, off;

		/*
		 * Calculate cbn, the logical superblock (sc_ileave chunks),
		 * and cboff, a normal block offset (DEV_BSIZE chunks) relative
		 * to cbn.
		 */
		cboff = cbn % cs->sc_ileave;	/* DEV_BSIZE gran */
		cbn = cbn / cs->sc_ileave;	/* DEV_BSIZE * ileave gran */

		/*
		 * Figure out which interleave table to use.
		 */
		for (ii = cs->sc_itable; ii->ii_ndisk; ii++) {
			if (ii->ii_startblk > cbn)
				break;
		}
		ii--;

		/*
		 * off is the logical superblock relative to the beginning 
		 * of this interleave block.  
		 */
		off = cbn - ii->ii_startblk;

		/*
		 * We must calculate which disk component to use (ccdisk),
		 * and recalculate cbn to be the superblock relative to
		 * the beginning of the component.  This is typically done by
		 * adding 'off' and ii->ii_startoff together.  However, 'off'
		 * must typically be divided by the number of components in
		 * this interleave array to be properly convert it from a
		 * CCD-relative logical superblock number to a 
		 * component-relative superblock number.
		 */
		if (ii->ii_ndisk == 1) {
			/*
			 * When we have just one disk, it can't be a mirror
			 * or a parity config.
			 */
			ccdisk = ii->ii_index[0];
			cbn = ii->ii_startoff + off;
		} else {
			if (cs->sc_cflags & CCDF_MIRROR) {
				/*
				 * We have forced a uniform mapping, resulting
				 * in a single interleave array.  We double
				 * up on the first half of the available
				 * components and our mirror is in the second
				 * half.  This only works with a single 
				 * interleave array because doubling up
				 * doubles the number of sectors, so there
				 * cannot be another interleave array because
				 * the next interleave array's calculations
				 * would be off.
				 */
				int ndisk2 = ii->ii_ndisk / 2;
				ccdisk = ii->ii_index[off % ndisk2];
				cbn = ii->ii_startoff + off / ndisk2;
				ci2 = &cs->sc_cinfo[ccdisk + ndisk2];
			} else if (cs->sc_cflags & CCDF_PARITY) {
				/* 
				 * XXX not implemented yet
				 */
				int ndisk2 = ii->ii_ndisk - 1;
				ccdisk = ii->ii_index[off % ndisk2];
				cbn = ii->ii_startoff + off / ndisk2;
				if (cbn % ii->ii_ndisk <= ccdisk)
					ccdisk++;
			} else {
				ccdisk = ii->ii_index[off % ii->ii_ndisk];
				cbn = ii->ii_startoff + off / ii->ii_ndisk;
			}
		}

		ci = &cs->sc_cinfo[ccdisk];

		/*
		 * Convert cbn from a superblock to a normal block so it
		 * can be used to calculate (along with cboff) the normal
		 * block index into this particular disk.
		 */
		cbn *= cs->sc_ileave;
	}

	/*
	 * Fill in the component buf structure.
	 */
	cbp = getccdbuf(NULL);
	cbp->cb_buf.b_flags = bp->b_flags | B_CALL;
	cbp->cb_buf.b_iodone = (void (*)(struct buf *))ccdiodone;
	cbp->cb_buf.b_dev = ci->ci_dev;		/* XXX */
	cbp->cb_buf.b_blkno = cbn + cboff + CCD_OFFSET;
	cbp->cb_buf.b_offset = dbtob(cbn + cboff + CCD_OFFSET);
	cbp->cb_buf.b_data = addr;
	cbp->cb_buf.b_vp = ci->ci_vp;
	if (cs->sc_ileave == 0)
              cbc = dbtob((off_t)(ci->ci_size - cbn));
	else
              cbc = dbtob((off_t)(cs->sc_ileave - cboff));
	cbp->cb_buf.b_bcount = (cbc < bcount) ? cbc : bcount;
 	cbp->cb_buf.b_bufsize = cbp->cb_buf.b_bcount;

	/*
	 * context for ccdiodone
	 */
	cbp->cb_obp = bp;
	cbp->cb_unit = cs - ccd_softc;
	cbp->cb_comp = ci - cs->sc_cinfo;

#ifdef DEBUG
	if (ccddebug & CCDB_IO)
		printf(" dev %x(u%d): cbp %x bn %d addr %x bcnt %d\n",
		       ci->ci_dev, ci-cs->sc_cinfo, cbp, cbp->cb_buf.b_blkno,
		       cbp->cb_buf.b_data, cbp->cb_buf.b_bcount);
#endif
	cb[0] = cbp;

	/*
	 * Note: both I/O's setup when reading from mirror, but only one
	 * will be executed.
	 */
	if (cs->sc_cflags & CCDF_MIRROR) {
		/* mirror, setup second I/O */
		cbp = getccdbuf(cb[0]);
		cbp->cb_buf.b_dev = ci2->ci_dev;
		cbp->cb_buf.b_vp = ci2->ci_vp;
		cbp->cb_comp = ci2 - cs->sc_cinfo;
		cb[1] = cbp;
		/* link together the ccdbuf's and clear "mirror done" flag */
		cb[0]->cb_mirror = cb[1];
		cb[1]->cb_mirror = cb[0];
		cb[0]->cb_pflags &= ~CCDPF_MIRROR_DONE;
		cb[1]->cb_pflags &= ~CCDPF_MIRROR_DONE;
	}
}

static void
ccdintr(cs, bp)
	struct ccd_softc *cs;
	struct buf *bp;
{
#ifdef DEBUG
	if (ccddebug & CCDB_FOLLOW)
		printf("ccdintr(%x, %x)\n", cs, bp);
#endif
	/*
	 * Request is done for better or worse, wakeup the top half.
	 */
	if (bp->b_flags & B_ERROR)
		bp->b_resid = bp->b_bcount;
	devstat_end_transaction_buf(&cs->device_stats, bp);
	biodone(bp);
}

/*
 * Called at interrupt time.
 * Mark the component as done and if all components are done,
 * take a ccd interrupt.
 */
static void
ccdiodone(cbp)
	struct ccdbuf *cbp;
{
	struct buf *bp = cbp->cb_obp;
	int unit = cbp->cb_unit;
	int count, s;

	s = splbio();
#ifdef DEBUG
	if (ccddebug & CCDB_FOLLOW)
		printf("ccdiodone(%x)\n", cbp);
	if (ccddebug & CCDB_IO) {
		printf("ccdiodone: bp %x bcount %d resid %d\n",
		       bp, bp->b_bcount, bp->b_resid);
		printf(" dev %x(u%d), cbp %x bn %d addr %x bcnt %d\n",
		       cbp->cb_buf.b_dev, cbp->cb_comp, cbp,
		       cbp->cb_buf.b_blkno, cbp->cb_buf.b_data,
		       cbp->cb_buf.b_bcount);
	}
#endif
	/*
	 * If an error occured, report it.  If this is a mirrored 
	 * configuration and the first of two possible reads, do not
	 * set the error in the bp yet because the second read may
	 * succeed.
	 */

	if (cbp->cb_buf.b_flags & B_ERROR) {
		const char *msg = "";

		if ((ccd_softc[unit].sc_cflags & CCDF_MIRROR) &&
		    (cbp->cb_buf.b_flags & B_READ) &&
		    (cbp->cb_pflags & CCDPF_MIRROR_DONE) == 0) {
			/*
			 * We will try our read on the other disk down
			 * below, also reverse the default pick so if we 
			 * are doing a scan we do not keep hitting the
			 * bad disk first.
			 */
			struct ccd_softc *cs = &ccd_softc[unit];

			msg = ", trying other disk";
			cs->sc_pick = 1 - cs->sc_pick;
			cs->sc_blk[cs->sc_pick] = bp->b_blkno;
		} else {
			bp->b_flags |= B_ERROR;
			bp->b_error = cbp->cb_buf.b_error ? 
			    cbp->cb_buf.b_error : EIO;
		}
		printf("ccd%d: error %d on component %d block %d (ccd block %d)%s\n",
		       unit, bp->b_error, cbp->cb_comp, 
		       (int)cbp->cb_buf.b_blkno, bp->b_blkno, msg);
	}

	/*
	 * Process mirror.  If we are writing, I/O has been initiated on both
	 * buffers and we fall through only after both are finished.
	 *
	 * If we are reading only one I/O is initiated at a time.  If an
	 * error occurs we initiate the second I/O and return, otherwise 
	 * we free the second I/O without initiating it.
	 */

	if (ccd_softc[unit].sc_cflags & CCDF_MIRROR) {
		if ((cbp->cb_buf.b_flags & B_READ) == 0) {
			/*
			 * When writing, handshake with the second buffer
			 * to determine when both are done.  If both are not
			 * done, return here.
			 */
			if ((cbp->cb_pflags & CCDPF_MIRROR_DONE) == 0) {
				cbp->cb_mirror->cb_pflags |= CCDPF_MIRROR_DONE;
				putccdbuf(cbp);
				splx(s);
				return;
			}
		} else {
			/*
			 * When reading, either dispose of the second buffer
			 * or initiate I/O on the second buffer if an error 
			 * occured with this one.
			 */
			if ((cbp->cb_pflags & CCDPF_MIRROR_DONE) == 0) {
				if (cbp->cb_buf.b_flags & B_ERROR) {
					cbp->cb_mirror->cb_pflags |= 
					    CCDPF_MIRROR_DONE;
					VOP_STRATEGY(
					    cbp->cb_mirror->cb_buf.b_vp, 
					    &cbp->cb_mirror->cb_buf
					);
					putccdbuf(cbp);
					splx(s);
					return;
				} else {
					putccdbuf(cbp->cb_mirror);
					/* fall through */
				}
			}
		}
	}

	/*
	 * use b_bufsize to determine how big the original request was rather
	 * then b_bcount, because b_bcount may have been truncated for EOF.
	 *
	 * XXX We check for an error, but we do not test the resid for an
	 * aligned EOF condition.  This may result in character & block
	 * device access not recognizing EOF properly when read or written 
	 * sequentially, but will not effect filesystems.
	 */
	count = cbp->cb_buf.b_bufsize;
	putccdbuf(cbp);

	/*
	 * If all done, "interrupt".
	 */
	bp->b_resid -= count;
	if (bp->b_resid < 0)
		panic("ccdiodone: count");
	if (bp->b_resid == 0)
		ccdintr(&ccd_softc[unit], bp);
	splx(s);
}

static int
ccdioctl(dev_t dev, u_long cmd, caddr_t data, int flag, d_thread_t *td)
{
	int unit = ccdunit(dev);
	int i, j, lookedup = 0, error = 0;
	int part, pmask, s;
	struct ccd_softc *cs;
	struct ccd_ioctl *ccio = (struct ccd_ioctl *)data;
	struct ccddevice ccd;
	char **cpp;
	struct vnode **vpp;
	struct ucred *cred;

	KKASSERT(td->td_proc != NULL);
	cred = td->td_proc->p_ucred;

	if (unit >= numccd)
		return (ENXIO);
	cs = &ccd_softc[unit];

	bzero(&ccd, sizeof(ccd));

	switch (cmd) {
	case CCDIOCSET:
		if (cs->sc_flags & CCDF_INITED)
			return (EBUSY);

		if ((flag & FWRITE) == 0)
			return (EBADF);

		if ((error = ccdlock(cs)) != 0)
			return (error);

		if (ccio->ccio_ndisks > CCD_MAXNDISKS)
			return (EINVAL);
 
		/* Fill in some important bits. */
		ccd.ccd_unit = unit;
		ccd.ccd_interleave = ccio->ccio_ileave;
		if (ccd.ccd_interleave == 0 &&
		    ((ccio->ccio_flags & CCDF_MIRROR) ||
		     (ccio->ccio_flags & CCDF_PARITY))) {
			printf("ccd%d: disabling mirror/parity, interleave is 0\n", unit);
			ccio->ccio_flags &= ~(CCDF_MIRROR | CCDF_PARITY);
		}
		if ((ccio->ccio_flags & CCDF_MIRROR) &&
		    (ccio->ccio_flags & CCDF_PARITY)) {
			printf("ccd%d: can't specify both mirror and parity, using mirror\n", unit);
			ccio->ccio_flags &= ~CCDF_PARITY;
		}
		if ((ccio->ccio_flags & (CCDF_MIRROR | CCDF_PARITY)) &&
		    !(ccio->ccio_flags & CCDF_UNIFORM)) {
			printf("ccd%d: mirror/parity forces uniform flag\n",
			       unit);
			ccio->ccio_flags |= CCDF_UNIFORM;
		}
		ccd.ccd_flags = ccio->ccio_flags & CCDF_USERMASK;

		/*
		 * Allocate space for and copy in the array of
		 * componet pathnames and device numbers.
		 */
		cpp = malloc(ccio->ccio_ndisks * sizeof(char *),
		    M_DEVBUF, M_WAITOK);
		vpp = malloc(ccio->ccio_ndisks * sizeof(struct vnode *),
		    M_DEVBUF, M_WAITOK);

		error = copyin((caddr_t)ccio->ccio_disks, (caddr_t)cpp,
		    ccio->ccio_ndisks * sizeof(char **));
		if (error) {
			free(vpp, M_DEVBUF);
			free(cpp, M_DEVBUF);
			ccdunlock(cs);
			return (error);
		}

#ifdef DEBUG
		if (ccddebug & CCDB_INIT)
			for (i = 0; i < ccio->ccio_ndisks; ++i)
				printf("ccdioctl: component %d: 0x%x\n",
				    i, cpp[i]);
#endif

		for (i = 0; i < ccio->ccio_ndisks; ++i) {
#ifdef DEBUG
			if (ccddebug & CCDB_INIT)
				printf("ccdioctl: lookedup = %d\n", lookedup);
#endif
			if ((error = ccdlookup(cpp[i], td, &vpp[i])) != 0) {
				for (j = 0; j < lookedup; ++j)
					(void)vn_close(vpp[j], FREAD|FWRITE, td);
				free(vpp, M_DEVBUF);
				free(cpp, M_DEVBUF);
				ccdunlock(cs);
				return (error);
			}
			++lookedup;
		}
		ccd.ccd_cpp = cpp;
		ccd.ccd_vpp = vpp;
		ccd.ccd_ndev = ccio->ccio_ndisks;

		/*
		 * Initialize the ccd.  Fills in the softc for us.
		 */
		if ((error = ccdinit(&ccd, cpp, td)) != 0) {
			for (j = 0; j < lookedup; ++j)
				(void)vn_close(vpp[j], FREAD|FWRITE, td);
			bzero(&ccd_softc[unit], sizeof(struct ccd_softc));
			free(vpp, M_DEVBUF);
			free(cpp, M_DEVBUF);
			ccdunlock(cs);
			return (error);
		}

		/*
		 * The ccd has been successfully initialized, so
		 * we can place it into the array and read the disklabel.
		 */
		bcopy(&ccd, &ccddevs[unit], sizeof(ccd));
		ccio->ccio_unit = unit;
		ccio->ccio_size = cs->sc_size;
		ccdgetdisklabel(dev);

		ccdunlock(cs);

		break;

	case CCDIOCCLR:
		if ((cs->sc_flags & CCDF_INITED) == 0)
			return (ENXIO);

		if ((flag & FWRITE) == 0)
			return (EBADF);

		if ((error = ccdlock(cs)) != 0)
			return (error);

		/* Don't unconfigure if any other partitions are open */
		part = ccdpart(dev);
		pmask = (1 << part);
		if ((cs->sc_openmask & ~pmask)) {
			ccdunlock(cs);
			return (EBUSY);
		}

		/*
		 * Free ccd_softc information and clear entry.
		 */

		/* Close the components and free their pathnames. */
		for (i = 0; i < cs->sc_nccdisks; ++i) {
			/*
			 * XXX: this close could potentially fail and
			 * cause Bad Things.  Maybe we need to force
			 * the close to happen?
			 */
#ifdef DEBUG
			if (ccddebug & CCDB_VNODE)
				vprint("CCDIOCCLR: vnode info",
				    cs->sc_cinfo[i].ci_vp);
#endif
			(void)vn_close(cs->sc_cinfo[i].ci_vp, FREAD|FWRITE, td);
			free(cs->sc_cinfo[i].ci_path, M_DEVBUF);
		}

		/* Free interleave index. */
		for (i = 0; cs->sc_itable[i].ii_ndisk; ++i)
			free(cs->sc_itable[i].ii_index, M_DEVBUF);

		/* Free component info and interleave table. */
		free(cs->sc_cinfo, M_DEVBUF);
		free(cs->sc_itable, M_DEVBUF);
		cs->sc_flags &= ~CCDF_INITED;

		/*
		 * Free ccddevice information and clear entry.
		 */
		free(ccddevs[unit].ccd_cpp, M_DEVBUF);
		free(ccddevs[unit].ccd_vpp, M_DEVBUF);
		ccd.ccd_dk = -1;
		bcopy(&ccd, &ccddevs[unit], sizeof(ccd));

		/*
		 * And remove the devstat entry.
		 */
		devstat_remove_entry(&cs->device_stats);

		/* This must be atomic. */
		s = splhigh();
		ccdunlock(cs);
		bzero(cs, sizeof(struct ccd_softc));
		splx(s);

		break;

	case DIOCGDINFO:
		if ((cs->sc_flags & CCDF_INITED) == 0)
			return (ENXIO);

		*(struct disklabel *)data = cs->sc_label;
		break;

	case DIOCGPART:
		if ((cs->sc_flags & CCDF_INITED) == 0)
			return (ENXIO);

		((struct partinfo *)data)->disklab = &cs->sc_label;
		((struct partinfo *)data)->part =
		    &cs->sc_label.d_partitions[ccdpart(dev)];
		break;

	case DIOCWDINFO:
	case DIOCSDINFO:
		if ((cs->sc_flags & CCDF_INITED) == 0)
			return (ENXIO);

		if ((flag & FWRITE) == 0)
			return (EBADF);

		if ((error = ccdlock(cs)) != 0)
			return (error);

		cs->sc_flags |= CCDF_LABELLING;

		error = setdisklabel(&cs->sc_label,
		    (struct disklabel *)data, 0);
		if (error == 0) {
			if (cmd == DIOCWDINFO) {
				dev_t cdev = CCDLABELDEV(dev);
				error = writedisklabel(cdev, &cs->sc_label);
			}
		}

		cs->sc_flags &= ~CCDF_LABELLING;

		ccdunlock(cs);

		if (error)
			return (error);
		break;

	case DIOCWLABEL:
		if ((cs->sc_flags & CCDF_INITED) == 0)
			return (ENXIO);

		if ((flag & FWRITE) == 0)
			return (EBADF);
		if (*(int *)data != 0)
			cs->sc_flags |= CCDF_WLABEL;
		else
			cs->sc_flags &= ~CCDF_WLABEL;
		break;

	default:
		return (ENOTTY);
	}

	return (0);
}

static int
ccdsize(dev_t dev)
{
	struct ccd_softc *cs;
	int part, size;

	if (ccdopen(dev, 0, S_IFCHR, curthread))
		return (-1);

	cs = &ccd_softc[ccdunit(dev)];
	part = ccdpart(dev);

	if ((cs->sc_flags & CCDF_INITED) == 0)
		return (-1);

	if (cs->sc_label.d_partitions[part].p_fstype != FS_SWAP)
		size = -1;
	else
		size = cs->sc_label.d_partitions[part].p_size;

	if (ccdclose(dev, 0, S_IFCHR, curthread))
		return (-1);

	return (size);
}

static int
ccddump(dev_t dev, u_int count, u_int blkno, u_int secsize)
{
	/* Not implemented. */
	return ENXIO;
}

/*
 * Lookup the provided name in the filesystem.  If the file exists,
 * is a valid block device, and isn't being used by anyone else,
 * set *vpp to the file's vnode.
 */
static int
ccdlookup(char *path, struct thread *td, struct vnode **vpp)
{
	struct nameidata nd;
	struct vnode *vp;
	int error;
	struct ucred *cred;

	KKASSERT(td->td_proc);
	cred = td->td_proc->p_ucred;

	NDINIT(&nd, NAMEI_LOOKUP, CNP_FOLLOW, UIO_USERSPACE, path, td);
	if ((error = vn_open(&nd, FREAD|FWRITE, 0)) != 0) {
#ifdef DEBUG
		if (ccddebug & CCDB_FOLLOW|CCDB_INIT)
			printf("ccdlookup: vn_open error = %d\n", error);
#endif
		return (error);
	}
	vp = nd.ni_vp;

	if (vp->v_usecount > 1) {
		error = EBUSY;
		goto bad;
	}

	if (!vn_isdisk(vp, &error)) 
		goto bad;

#ifdef DEBUG
	if (ccddebug & CCDB_VNODE)
		vprint("ccdlookup: vnode info", vp);
#endif

	VOP_UNLOCK(vp, NULL, 0, td);
	NDFREE(&nd, NDF_ONLY_PNBUF);
	*vpp = vp;
	return (0);
bad:
	VOP_UNLOCK(vp, NULL, 0, td);
	NDFREE(&nd, NDF_ONLY_PNBUF);
	/* vn_close does vrele() for vp */
	(void)vn_close(vp, FREAD|FWRITE, td);
	return (error);
}

/*
 * Read the disklabel from the ccd.  If one is not present, fake one
 * up.
 */
static void
ccdgetdisklabel(dev)
	dev_t dev;
{
	int unit = ccdunit(dev);
	struct ccd_softc *cs = &ccd_softc[unit];
	char *errstring;
	struct disklabel *lp = &cs->sc_label;
	struct ccdgeom *ccg = &cs->sc_geom;
	dev_t cdev;

	bzero(lp, sizeof(*lp));

	lp->d_secperunit = cs->sc_size;
	lp->d_secsize = ccg->ccg_secsize;
	lp->d_nsectors = ccg->ccg_nsectors;
	lp->d_ntracks = ccg->ccg_ntracks;
	lp->d_ncylinders = ccg->ccg_ncylinders;
	lp->d_secpercyl = lp->d_ntracks * lp->d_nsectors;

	strncpy(lp->d_typename, "ccd", sizeof(lp->d_typename));
	lp->d_type = DTYPE_CCD;
	strncpy(lp->d_packname, "fictitious", sizeof(lp->d_packname));
	lp->d_rpm = 3600;
	lp->d_interleave = 1;
	lp->d_flags = 0;

	lp->d_partitions[RAW_PART].p_offset = 0;
	lp->d_partitions[RAW_PART].p_size = cs->sc_size;
	lp->d_partitions[RAW_PART].p_fstype = FS_UNUSED;
	lp->d_npartitions = RAW_PART + 1;

	lp->d_bbsize = BBSIZE;				/* XXX */
	lp->d_sbsize = SBSIZE;				/* XXX */

	lp->d_magic = DISKMAGIC;
	lp->d_magic2 = DISKMAGIC;
	lp->d_checksum = dkcksum(&cs->sc_label);

	/*
	 * Call the generic disklabel extraction routine.
	 */
	cdev = CCDLABELDEV(dev);
	errstring = readdisklabel(cdev, &cs->sc_label);
	if (errstring != NULL)
		ccdmakedisklabel(cs);

#ifdef DEBUG
	/* It's actually extremely common to have unlabeled ccds. */
	if (ccddebug & CCDB_LABEL)
		if (errstring != NULL)
			printf("ccd%d: %s\n", unit, errstring);
#endif
}

/*
 * Take care of things one might want to take care of in the event
 * that a disklabel isn't present.
 */
static void
ccdmakedisklabel(cs)
	struct ccd_softc *cs;
{
	struct disklabel *lp = &cs->sc_label;

	/*
	 * For historical reasons, if there's no disklabel present
	 * the raw partition must be marked FS_BSDFFS.
	 */
	lp->d_partitions[RAW_PART].p_fstype = FS_BSDFFS;

	strncpy(lp->d_packname, "default label", sizeof(lp->d_packname));
}

/*
 * Wait interruptibly for an exclusive lock.
 *
 * XXX
 * Several drivers do this; it should be abstracted and made MP-safe.
 */
static int
ccdlock(cs)
	struct ccd_softc *cs;
{
	int error;

	while ((cs->sc_flags & CCDF_LOCKED) != 0) {
		cs->sc_flags |= CCDF_WANTED;
		if ((error = tsleep(cs, PCATCH, "ccdlck", 0)) != 0)
			return (error);
	}
	cs->sc_flags |= CCDF_LOCKED;
	return (0);
}

/*
 * Unlock and wake up any waiters.
 */
static void
ccdunlock(cs)
	struct ccd_softc *cs;
{

	cs->sc_flags &= ~CCDF_LOCKED;
	if ((cs->sc_flags & CCDF_WANTED) != 0) {
		cs->sc_flags &= ~CCDF_WANTED;
		wakeup(cs);
	}
}

#ifdef DEBUG
static void
printiinfo(ii)
	struct ccdiinfo *ii;
{
	int ix, i;

	for (ix = 0; ii->ii_ndisk; ix++, ii++) {
		printf(" itab[%d]: #dk %d sblk %d soff %d",
		       ix, ii->ii_ndisk, ii->ii_startblk, ii->ii_startoff);
		for (i = 0; i < ii->ii_ndisk; i++)
			printf(" %d", ii->ii_index[i]);
		printf("\n");
	}
}
#endif


/* Local Variables: */
/* c-argdecl-indent: 8 */
/* c-continued-statement-offset: 8 */
/* c-indent-level: 8 */
/* End: */