freebsd-dev/sys/geom/geom_disk.c

/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 2002 Poul-Henning Kamp
 * Copyright (c) 2002 Networks Associates Technology, Inc.
 * All rights reserved.
 *
 * This software was developed for the FreeBSD Project by Poul-Henning Kamp
 * and NAI Labs, the Security Research Division of Network Associates, Inc.
 * under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the
 * DARPA CHATS research program.
 *
 * 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. The names of the authors 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 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 AUTHOR 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.
 */

#include <sys/cdefs.h>
#include "opt_geom.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/sysctl.h>
#include <sys/bio.h>
#include <sys/ctype.h>
#include <sys/devctl.h>
#include <sys/fcntl.h>
#include <sys/malloc.h>
#include <sys/msan.h>
#include <sys/sbuf.h>
#include <sys/devicestat.h>

#include <sys/lock.h>
#include <sys/mutex.h>
#include <geom/geom.h>
#include <geom/geom_disk.h>
#include <geom/geom_int.h>

#include <dev/led/led.h>

#include <machine/bus.h>

struct g_disk_softc {
	struct disk		*dp;
	struct devstat		*d_devstat;
	struct sysctl_ctx_list	sysctl_ctx;
	struct sysctl_oid	*sysctl_tree;
	char			led[64];
	uint32_t		state;
	struct mtx		 done_mtx;
	bool                    flush_notsup_succeed;
};

static g_access_t g_disk_access;
static g_start_t g_disk_start;
static g_ioctl_t g_disk_ioctl;
static g_dumpconf_t g_disk_dumpconf;
static g_provgone_t g_disk_providergone;

static int g_disk_sysctl_flags(SYSCTL_HANDLER_ARGS);

static struct g_class g_disk_class = {
	.name = G_DISK_CLASS_NAME,
	.version = G_VERSION,
	.start = g_disk_start,
	.access = g_disk_access,
	.ioctl = g_disk_ioctl,
	.providergone = g_disk_providergone,
	.dumpconf = g_disk_dumpconf,
};

SYSCTL_DECL(_kern_geom);
static SYSCTL_NODE(_kern_geom, OID_AUTO, disk, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
    "GEOM_DISK stuff");

DECLARE_GEOM_CLASS(g_disk_class, g_disk);

static int
g_disk_access(struct g_provider *pp, int r, int w, int e)
{
	struct disk *dp;
	struct g_disk_softc *sc;
	int error;

	g_trace(G_T_ACCESS, "g_disk_access(%s, %d, %d, %d)",
	    pp->name, r, w, e);
	g_topology_assert();
	sc = pp->private;
	if ((dp = sc->dp) == NULL || dp->d_destroyed) {
		/*
		 * Allow decreasing access count even if disk is not
		 * available anymore.
		 */
		if (r <= 0 && w <= 0 && e <= 0)
			return (0);
		return (ENXIO);
	}
	r += pp->acr;
	w += pp->acw;
	e += pp->ace;
	error = 0;
	if ((pp->acr + pp->acw + pp->ace) == 0 && (r + w + e) > 0) {
		/*
		 * It would be better to defer this decision to d_open if
		 * it was able to take flags.
		 */
		if (w > 0 && (dp->d_flags & DISKFLAG_WRITE_PROTECT) != 0)
			error = EROFS;
		if (error == 0 && dp->d_open != NULL)
			error = dp->d_open(dp);
		if (bootverbose && error != 0)
			printf("Opened disk %s -> %d\n", pp->name, error);
		if (error != 0)
			return (error);
		pp->sectorsize = dp->d_sectorsize;
		if (dp->d_maxsize == 0) {
			printf("WARNING: Disk drive %s%d has no d_maxsize\n",
			    dp->d_name, dp->d_unit);
			dp->d_maxsize = DFLTPHYS;
		}
		if (dp->d_delmaxsize == 0) {
			if (bootverbose && dp->d_flags & DISKFLAG_CANDELETE) {
				printf("WARNING: Disk drive %s%d has no "
				    "d_delmaxsize\n", dp->d_name, dp->d_unit);
			}
			dp->d_delmaxsize = dp->d_maxsize;
		}
		pp->stripeoffset = dp->d_stripeoffset;
		pp->stripesize = dp->d_stripesize;
		dp->d_flags |= DISKFLAG_OPEN;
		/*
		 * Do not invoke resize event when initial size was zero.
		 * Some disks report its size only after first opening.
		 */
		if (pp->mediasize == 0)
			pp->mediasize = dp->d_mediasize;
		else
			g_resize_provider(pp, dp->d_mediasize);
	} else if ((pp->acr + pp->acw + pp->ace) > 0 && (r + w + e) == 0) {
		if (dp->d_close != NULL) {
			error = dp->d_close(dp);
			if (error != 0)
				printf("Closed disk %s -> %d\n",
				    pp->name, error);
		}
		sc->state = G_STATE_ACTIVE;
		if (sc->led[0] != 0)
			led_set(sc->led, "0");
		dp->d_flags &= ~DISKFLAG_OPEN;
	}
	return (error);
}

static void
g_disk_kerneldump(struct bio *bp, struct disk *dp)
{
	struct g_kerneldump *gkd;
	struct g_geom *gp;

	gkd = (struct g_kerneldump*)bp->bio_data;
	gp = bp->bio_to->geom;
	g_trace(G_T_TOPOLOGY, "g_disk_kerneldump(%s, %jd, %jd)",
		gp->name, (intmax_t)gkd->offset, (intmax_t)gkd->length);
	if (dp->d_dump == NULL) {
		g_io_deliver(bp, ENODEV);
		return;
	}
	gkd->di.dumper = dp->d_dump;
	gkd->di.priv = dp;
	gkd->di.blocksize = dp->d_sectorsize;
	gkd->di.maxiosize = dp->d_maxsize;
	gkd->di.mediaoffset = gkd->offset;
	if ((gkd->offset + gkd->length) > dp->d_mediasize)
		gkd->length = dp->d_mediasize - gkd->offset;
	gkd->di.mediasize = gkd->length;
	g_io_deliver(bp, 0);
}

static void
g_disk_setstate(struct bio *bp, struct g_disk_softc *sc)
{
	const char *cmd;

	memcpy(&sc->state, bp->bio_data, sizeof(sc->state));
	if (sc->led[0] != 0) {
		switch (sc->state) {
		case G_STATE_FAILED:
			cmd = "1";
			break;
		case G_STATE_REBUILD:
			cmd = "f5";
			break;
		case G_STATE_RESYNC:
			cmd = "f1";
			break;
		default:
			cmd = "0";
			break;
		}
		led_set(sc->led, cmd);
	}
	g_io_deliver(bp, 0);
}

static void
g_disk_done(struct bio *bp)
{
	struct bintime now;
	struct bio *bp2;
	struct g_disk_softc *sc;

	/* See "notes" for why we need a mutex here */
	sc = bp->bio_caller1;
	bp2 = bp->bio_parent;
	binuptime(&now);
	mtx_lock(&sc->done_mtx);
	if (bp2->bio_error == 0)
		bp2->bio_error = bp->bio_error;
	bp2->bio_completed += bp->bio_length - bp->bio_resid;

	if (bp->bio_cmd == BIO_READ)
		kmsan_check(bp2->bio_data, bp2->bio_completed, "g_disk_done");

	switch (bp->bio_cmd) {
	case BIO_ZONE:
		bcopy(&bp->bio_zone, &bp2->bio_zone, sizeof(bp->bio_zone));
		/*FALLTHROUGH*/
	case BIO_READ:
	case BIO_WRITE:
	case BIO_DELETE:
	case BIO_FLUSH:
		devstat_end_transaction_bio_bt(sc->d_devstat, bp, &now);
		break;
	default:
		break;
	}
	bp2->bio_inbed++;
	if (bp2->bio_children == bp2->bio_inbed) {
		mtx_unlock(&sc->done_mtx);
		bp2->bio_resid = bp2->bio_bcount - bp2->bio_completed;
		g_io_deliver(bp2, bp2->bio_error);
	} else
		mtx_unlock(&sc->done_mtx);
	g_destroy_bio(bp);
}

static int
g_disk_ioctl(struct g_provider *pp, u_long cmd, void * data, int fflag, struct thread *td)
{
	struct disk *dp;
	struct g_disk_softc *sc;

	sc = pp->private;
	dp = sc->dp;
	KASSERT(dp != NULL && !dp->d_destroyed,
	    ("g_disk_ioctl(%lx) on destroyed disk %s", cmd, pp->name));

	if (dp->d_ioctl == NULL)
		return (ENOIOCTL);
	return (dp->d_ioctl(dp, cmd, data, fflag, td));
}

static off_t
g_disk_maxsize(struct disk *dp, struct bio *bp)
{
	if (bp->bio_cmd == BIO_DELETE)
		return (dp->d_delmaxsize);
	return (dp->d_maxsize);
}

static int
g_disk_maxsegs(struct disk *dp, struct bio *bp)
{
	return ((g_disk_maxsize(dp, bp) / PAGE_SIZE) + 1);
}

static void
g_disk_advance(struct disk *dp, struct bio *bp, off_t off)
{

	bp->bio_offset += off;
	bp->bio_length -= off;

	if ((bp->bio_flags & BIO_VLIST) != 0) {
		bus_dma_segment_t *seg, *end;

		seg = (bus_dma_segment_t *)bp->bio_data;
		end = (bus_dma_segment_t *)bp->bio_data + bp->bio_ma_n;
		off += bp->bio_ma_offset;
		while (off >= seg->ds_len) {
			KASSERT((seg != end),
			    ("vlist request runs off the end"));
			off -= seg->ds_len;
			seg++;
		}
		bp->bio_ma_offset = off;
		bp->bio_ma_n = end - seg;
		bp->bio_data = (void *)seg;
	} else if ((bp->bio_flags & BIO_UNMAPPED) != 0) {
		bp->bio_ma += off / PAGE_SIZE;
		bp->bio_ma_offset += off;
		bp->bio_ma_offset %= PAGE_SIZE;
		bp->bio_ma_n -= off / PAGE_SIZE;
	} else {
		bp->bio_data += off;
	}
}

static void
g_disk_seg_limit(bus_dma_segment_t *seg, off_t *poffset,
    off_t *plength, int *ppages)
{
	uintptr_t seg_page_base;
	uintptr_t seg_page_end;
	off_t offset;
	off_t length;
	int seg_pages;

	offset = *poffset;
	length = *plength;

	if (length > seg->ds_len - offset)
		length = seg->ds_len - offset;

	seg_page_base = trunc_page(seg->ds_addr + offset);
	seg_page_end  = round_page(seg->ds_addr + offset + length);
	seg_pages = (seg_page_end - seg_page_base) >> PAGE_SHIFT;

	if (seg_pages > *ppages) {
		seg_pages = *ppages;
		length = (seg_page_base + (seg_pages << PAGE_SHIFT)) -
		    (seg->ds_addr + offset);
	}

	*poffset = 0;
	*plength -= length;
	*ppages -= seg_pages;
}

static off_t
g_disk_vlist_limit(struct disk *dp, struct bio *bp, bus_dma_segment_t **pendseg)
{
	bus_dma_segment_t *seg, *end __diagused;
	off_t residual;
	off_t offset;
	int pages;

	seg = (bus_dma_segment_t *)bp->bio_data;
	end = (bus_dma_segment_t *)bp->bio_data + bp->bio_ma_n;
	residual = bp->bio_length;
	offset = bp->bio_ma_offset;
	pages = g_disk_maxsegs(dp, bp);
	while (residual != 0 && pages != 0) {
		KASSERT((seg != end),
		    ("vlist limit runs off the end"));
		g_disk_seg_limit(seg, &offset, &residual, &pages);
		seg++;
	}
	if (pendseg != NULL)
		*pendseg = seg;
	return (residual);
}

static bool
g_disk_limit(struct disk *dp, struct bio *bp)
{
	bool limited = false;
	off_t maxsz;

	maxsz = g_disk_maxsize(dp, bp);

	/*
	 * XXX: If we have a stripesize we should really use it here.
	 *      Care should be taken in the delete case if this is done
	 *      as deletes can be very sensitive to size given how they
	 *      are processed.
	 */
	if (bp->bio_length > maxsz) {
		bp->bio_length = maxsz;
		limited = true;
	}

	if ((bp->bio_flags & BIO_VLIST) != 0) {
		bus_dma_segment_t *firstseg, *endseg;
		off_t residual;

		firstseg = (bus_dma_segment_t*)bp->bio_data;
		residual = g_disk_vlist_limit(dp, bp, &endseg);
		if (residual != 0) {
			bp->bio_ma_n = endseg - firstseg;
			bp->bio_length -= residual;
			limited = true;
		}
	} else if ((bp->bio_flags & BIO_UNMAPPED) != 0) {
		bp->bio_ma_n =
		    howmany(bp->bio_ma_offset + bp->bio_length, PAGE_SIZE);
	}

	return (limited);
}

static void
g_disk_start(struct bio *bp)
{
	struct bio *bp2, *bp3;
	struct disk *dp;
	struct g_disk_softc *sc;
	int error;
	off_t off;

	biotrack(bp, __func__);

	sc = bp->bio_to->private;
	dp = sc->dp;
	KASSERT(dp != NULL && !dp->d_destroyed,
	    ("g_disk_start(%p) on destroyed disk %s", bp, bp->bio_to->name));
	error = EJUSTRETURN;
	switch(bp->bio_cmd) {
	case BIO_DELETE:
		if (!(dp->d_flags & DISKFLAG_CANDELETE)) {
			error = EOPNOTSUPP;
			break;
		}
		/* fall-through */
	case BIO_READ:
	case BIO_WRITE:
		KASSERT((dp->d_flags & DISKFLAG_UNMAPPED_BIO) != 0 ||
		    (bp->bio_flags & BIO_UNMAPPED) == 0,
		    ("unmapped bio not supported by disk %s", dp->d_name));

		if (bp->bio_cmd == BIO_WRITE)
			kmsan_check_bio(bp, "g_disk_start");

		off = 0;
		bp3 = NULL;
		bp2 = g_clone_bio(bp);
		if (bp2 == NULL) {
			error = ENOMEM;
			break;
		}
		for (;;) {
			if (g_disk_limit(dp, bp2)) {
				off += bp2->bio_length;

				/*
				 * To avoid a race, we need to grab the next bio
				 * before we schedule this one.  See "notes".
				 */
				bp3 = g_clone_bio(bp);
				if (bp3 == NULL)
					bp->bio_error = ENOMEM;
			}
			bp2->bio_done = g_disk_done;
			bp2->bio_caller1 = sc;
			bp2->bio_pblkno = bp2->bio_offset / dp->d_sectorsize;
			bp2->bio_bcount = bp2->bio_length;
			bp2->bio_disk = dp;
			devstat_start_transaction_bio(dp->d_devstat, bp2);
			dp->d_strategy(bp2);

			if (bp3 == NULL)
				break;

			bp2 = bp3;
			bp3 = NULL;
			g_disk_advance(dp, bp2, off);
		}
		break;
	case BIO_GETATTR:
		/* Give the driver a chance to override */
		if (dp->d_getattr != NULL) {
			if (bp->bio_disk == NULL)
				bp->bio_disk = dp;
			error = dp->d_getattr(bp);
			if (error != -1)
				break;
			error = EJUSTRETURN;
		}
		if (g_handleattr_int(bp, "GEOM::candelete",
		    (dp->d_flags & DISKFLAG_CANDELETE) != 0))
			break;
		else if (g_handleattr_int(bp, "GEOM::fwsectors",
		    dp->d_fwsectors))
			break;
		else if (g_handleattr_int(bp, "GEOM::fwheads", dp->d_fwheads))
			break;
		else if (g_handleattr_str(bp, "GEOM::ident", dp->d_ident))
			break;
		else if (g_handleattr_str(bp, "GEOM::descr", dp->d_descr))
			break;
		else if (g_handleattr_uint16_t(bp, "GEOM::hba_vendor",
		    dp->d_hba_vendor))
			break;
		else if (g_handleattr_uint16_t(bp, "GEOM::hba_device",
		    dp->d_hba_device))
			break;
		else if (g_handleattr_uint16_t(bp, "GEOM::hba_subvendor",
		    dp->d_hba_subvendor))
			break;
		else if (g_handleattr_uint16_t(bp, "GEOM::hba_subdevice",
		    dp->d_hba_subdevice))
			break;
		else if (!strcmp(bp->bio_attribute, "GEOM::kerneldump"))
			g_disk_kerneldump(bp, dp);
		else if (!strcmp(bp->bio_attribute, "GEOM::setstate"))
			g_disk_setstate(bp, sc);
		else if (g_handleattr_uint16_t(bp, "GEOM::rotation_rate",
		    dp->d_rotation_rate))
			break;
		else if (g_handleattr_str(bp, "GEOM::attachment",
		    dp->d_attachment))
			break;
		else
			error = ENOIOCTL;
		break;
	case BIO_FLUSH:
		g_trace(G_T_BIO, "g_disk_flushcache(%s)",
		    bp->bio_to->name);
		if (!(dp->d_flags & DISKFLAG_CANFLUSHCACHE)) {
			error = (sc->flush_notsup_succeed) ? 0 : EOPNOTSUPP;
			break;
		}
		/*FALLTHROUGH*/
	case BIO_ZONE:
		if (bp->bio_cmd == BIO_ZONE) {
			if (!(dp->d_flags & DISKFLAG_CANZONE)) {
				error = EOPNOTSUPP;
				break;
			}
			g_trace(G_T_BIO, "g_disk_zone(%s)",
			    bp->bio_to->name);
		}
		bp2 = g_clone_bio(bp);
		if (bp2 == NULL) {
			g_io_deliver(bp, ENOMEM);
			return;
		}
		bp2->bio_done = g_disk_done;
		bp2->bio_caller1 = sc;
		bp2->bio_disk = dp;
		devstat_start_transaction_bio(dp->d_devstat, bp2);
		dp->d_strategy(bp2);
		break;
	case BIO_SPEEDUP:
		bp2 = g_clone_bio(bp);
		if (bp2 == NULL) {
			g_io_deliver(bp, ENOMEM);
			return;
		}
		bp2->bio_done = g_disk_done;
		bp2->bio_caller1 = sc;
		bp2->bio_disk = dp;
		dp->d_strategy(bp2);
		break;
	default:
		error = EOPNOTSUPP;
		break;
	}
	if (error != EJUSTRETURN)
		g_io_deliver(bp, error);
	return;
}

static void
g_disk_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp, struct g_consumer *cp, struct g_provider *pp)
{
	struct bio *bp;
	struct disk *dp;
	struct g_disk_softc *sc;
	char *buf;
	int res = 0;

	sc = gp->softc;
	if (sc == NULL || (dp = sc->dp) == NULL)
		return;
	if (indent == NULL) {
		sbuf_printf(sb, " hd %u", dp->d_fwheads);
		sbuf_printf(sb, " sc %u", dp->d_fwsectors);
		return;
	}
	if (pp != NULL) {
		sbuf_printf(sb, "%s<fwheads>%u</fwheads>\n",
		    indent, dp->d_fwheads);
		sbuf_printf(sb, "%s<fwsectors>%u</fwsectors>\n",
		    indent, dp->d_fwsectors);

		/*
		 * "rotationrate" is a little complicated, because the value
		 * returned by the drive might not be the RPM; 0 and 1 are
		 * special cases, and there's also a valid range.
		 */
		sbuf_printf(sb, "%s<rotationrate>", indent);
		if (dp->d_rotation_rate == DISK_RR_UNKNOWN) /* Old drives */
			sbuf_cat(sb, "unknown");	/* don't report RPM. */
		else if (dp->d_rotation_rate == DISK_RR_NON_ROTATING)
			sbuf_cat(sb, "0");
		else if ((dp->d_rotation_rate >= DISK_RR_MIN) &&
		    (dp->d_rotation_rate <= DISK_RR_MAX))
			sbuf_printf(sb, "%u", dp->d_rotation_rate);
		else
			sbuf_cat(sb, "invalid");
		sbuf_cat(sb, "</rotationrate>\n");
		if (dp->d_getattr != NULL) {
			buf = g_malloc(DISK_IDENT_SIZE, M_WAITOK);
			bp = g_alloc_bio();
			bp->bio_disk = dp;
			bp->bio_attribute = "GEOM::ident";
			bp->bio_length = DISK_IDENT_SIZE;
			bp->bio_data = buf;
			res = dp->d_getattr(bp);
			sbuf_printf(sb, "%s<ident>", indent);
			g_conf_cat_escaped(sb, res == 0 ? buf : dp->d_ident);
			sbuf_cat(sb, "</ident>\n");
			bp->bio_attribute = "GEOM::lunid";
			bp->bio_length = DISK_IDENT_SIZE;
			bp->bio_data = buf;
			if (dp->d_getattr(bp) == 0) {
				sbuf_printf(sb, "%s<lunid>", indent);
				g_conf_cat_escaped(sb, buf);
				sbuf_cat(sb, "</lunid>\n");
			}
			bp->bio_attribute = "GEOM::lunname";
			bp->bio_length = DISK_IDENT_SIZE;
			bp->bio_data = buf;
			if (dp->d_getattr(bp) == 0) {
				sbuf_printf(sb, "%s<lunname>", indent);
				g_conf_cat_escaped(sb, buf);
				sbuf_cat(sb, "</lunname>\n");
			}
			g_destroy_bio(bp);
			g_free(buf);
		} else {
			sbuf_printf(sb, "%s<ident>", indent);
			g_conf_cat_escaped(sb, dp->d_ident);
			sbuf_cat(sb, "</ident>\n");
		}
		sbuf_printf(sb, "%s<descr>", indent);
		g_conf_cat_escaped(sb, dp->d_descr);
		sbuf_cat(sb, "</descr>\n");
	}
}

static void
g_disk_resize(void *ptr, int flag)
{
	struct disk *dp;
	struct g_geom *gp;
	struct g_provider *pp;

	if (flag == EV_CANCEL)
		return;
	g_topology_assert();

	dp = ptr;
	gp = dp->d_geom;

	if (dp->d_destroyed || gp == NULL)
		return;

	LIST_FOREACH(pp, &gp->provider, provider) {
		if (pp->sectorsize != 0 &&
		    pp->sectorsize != dp->d_sectorsize)
			g_wither_provider(pp, ENXIO);
		else
			g_resize_provider(pp, dp->d_mediasize);
	}
}

static void
g_disk_create(void *arg, int flag)
{
	struct g_geom *gp;
	struct g_provider *pp;
	struct disk *dp;
	struct g_disk_softc *sc;
	struct disk_alias *dap;
	char tmpstr[80];

	if (flag == EV_CANCEL)
		return;
	g_topology_assert();
	dp = arg;

	mtx_pool_lock(mtxpool_sleep, dp);
	dp->d_init_level = DISK_INIT_START;

	/*
	 * If the disk has already gone away, we can just stop here and
	 * call the user's callback to tell him we've cleaned things up.
	 */
	if (dp->d_goneflag != 0) {
		mtx_pool_unlock(mtxpool_sleep, dp);
		if (dp->d_gone != NULL)
			dp->d_gone(dp);
		return;
	}
	mtx_pool_unlock(mtxpool_sleep, dp);

	sc = g_malloc(sizeof(*sc), M_WAITOK | M_ZERO);
	mtx_init(&sc->done_mtx, "g_disk_done", NULL, MTX_DEF);
	sc->dp = dp;
	if (dp->d_devstat == NULL) {
		dp->d_devstat = devstat_new_entry(dp->d_name, dp->d_unit,
		    dp->d_sectorsize, DEVSTAT_ALL_SUPPORTED,
		    DEVSTAT_TYPE_DIRECT, DEVSTAT_PRIORITY_MAX);
	}
	sc->d_devstat = dp->d_devstat;
	gp = g_new_geomf(&g_disk_class, "%s%d", dp->d_name, dp->d_unit);
	gp->softc = sc;
	pp = g_new_providerf(gp, "%s", gp->name);
	LIST_FOREACH(dap, &dp->d_aliases, da_next)
		g_provider_add_alias(pp, "%s%d", dap->da_alias, dp->d_unit);
	devstat_remove_entry(pp->stat);
	pp->stat = NULL;
	dp->d_devstat->id = pp;
	pp->mediasize = dp->d_mediasize;
	pp->sectorsize = dp->d_sectorsize;
	pp->stripeoffset = dp->d_stripeoffset;
	pp->stripesize = dp->d_stripesize;
	if ((dp->d_flags & DISKFLAG_UNMAPPED_BIO) != 0)
		pp->flags |= G_PF_ACCEPT_UNMAPPED;
	if ((dp->d_flags & DISKFLAG_DIRECT_COMPLETION) != 0)
		pp->flags |= G_PF_DIRECT_SEND;
	pp->flags |= G_PF_DIRECT_RECEIVE;
	if (bootverbose)
		printf("GEOM: new disk %s\n", gp->name);
	sysctl_ctx_init(&sc->sysctl_ctx);
	snprintf(tmpstr, sizeof(tmpstr), "GEOM disk %s", gp->name);
	sc->sysctl_tree = SYSCTL_ADD_NODE(&sc->sysctl_ctx,
		SYSCTL_STATIC_CHILDREN(_kern_geom_disk), OID_AUTO, gp->name,
		CTLFLAG_RD | CTLFLAG_MPSAFE, 0, tmpstr);
	if (sc->sysctl_tree != NULL) {
		SYSCTL_ADD_STRING(&sc->sysctl_ctx,
		    SYSCTL_CHILDREN(sc->sysctl_tree), OID_AUTO, "led",
		    CTLFLAG_RWTUN, sc->led, sizeof(sc->led),
		    "LED name");
		SYSCTL_ADD_PROC(&sc->sysctl_ctx,
		    SYSCTL_CHILDREN(sc->sysctl_tree), OID_AUTO, "flags",
		    CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, dp, 0,
		    g_disk_sysctl_flags, "A", "Report disk flags");
		SYSCTL_ADD_BOOL(&sc->sysctl_ctx,
		    SYSCTL_CHILDREN(sc->sysctl_tree), OID_AUTO, "flush_notsup_succeed",
		    CTLFLAG_RWTUN, &sc->flush_notsup_succeed, sizeof(sc->flush_notsup_succeed),
		    "Do not return EOPNOTSUPP if there is no cache to flush");
	}
	pp->private = sc;
	dp->d_geom = gp;
	g_error_provider(pp, 0);

	mtx_pool_lock(mtxpool_sleep, dp);
	dp->d_init_level = DISK_INIT_DONE;

	/*
	 * If the disk has gone away at this stage, start the withering
	 * process for it.
	 */
	if (dp->d_goneflag != 0) {
		mtx_pool_unlock(mtxpool_sleep, dp);
		g_wither_provider(pp, ENXIO);
		return;
	}
	mtx_pool_unlock(mtxpool_sleep, dp);

}

/*
 * We get this callback after all of the consumers have gone away, and just
 * before the provider is freed.  If the disk driver provided a d_gone
 * callback, let them know that it is okay to free resources -- they won't
 * be getting any more accesses from GEOM.
 */
static void
g_disk_providergone(struct g_provider *pp)
{
	struct disk *dp;
	struct g_disk_softc *sc;

	sc = (struct g_disk_softc *)pp->private;
	dp = sc->dp;
	if (dp != NULL && dp->d_gone != NULL)
		dp->d_gone(dp);
	if (sc->sysctl_tree != NULL) {
		sysctl_ctx_free(&sc->sysctl_ctx);
		sc->sysctl_tree = NULL;
	}
	if (sc->led[0] != 0) {
		led_set(sc->led, "0");
		sc->led[0] = 0;
	}
	pp->private = NULL;
	pp->geom->softc = NULL;
	mtx_destroy(&sc->done_mtx);
	g_free(sc);
}

static void
g_disk_destroy(void *ptr, int flag)
{
	struct disk *dp;
	struct g_geom *gp;
	struct g_disk_softc *sc;
	struct disk_alias *dap, *daptmp;

	g_topology_assert();
	dp = ptr;
	gp = dp->d_geom;
	if (gp != NULL) {
		sc = gp->softc;
		if (sc != NULL)
			sc->dp = NULL;
		dp->d_geom = NULL;
		g_wither_geom(gp, ENXIO);
	}
	LIST_FOREACH_SAFE(dap, &dp->d_aliases, da_next, daptmp)
		g_free(dap);

	g_free(dp);
}

/*
 * We only allow printable characters in disk ident,
 * the rest is converted to 'x<HH>'.
 */
static void
g_disk_ident_adjust(char *ident, size_t size)
{
	char *p, tmp[4], newid[DISK_IDENT_SIZE];

	newid[0] = '\0';
	for (p = ident; *p != '\0'; p++) {
		if (isprint(*p)) {
			tmp[0] = *p;
			tmp[1] = '\0';
		} else {
			snprintf(tmp, sizeof(tmp), "x%02hhx",
			    *(unsigned char *)p);
		}
		if (strlcat(newid, tmp, sizeof(newid)) >= sizeof(newid))
			break;
	}
	bzero(ident, size);
	strlcpy(ident, newid, size);
}

struct disk *
disk_alloc(void)
{
	struct disk *dp;

	dp = g_malloc(sizeof(struct disk), M_WAITOK | M_ZERO);
	LIST_INIT(&dp->d_aliases);
	dp->d_init_level = DISK_INIT_NONE;
	dp->d_cevent = g_alloc_event(M_WAITOK);
	dp->d_devent = g_alloc_event(M_WAITOK);
	return (dp);
}

void
disk_create(struct disk *dp, int version)
{

	if (version != DISK_VERSION) {
		printf("WARNING: Attempt to add disk %s%d %s",
		    dp->d_name, dp->d_unit,
		    " using incompatible ABI version of disk(9)\n");
		printf("WARNING: Ignoring disk %s%d\n",
		    dp->d_name, dp->d_unit);
		return;
	}
	if (dp->d_flags & DISKFLAG_RESERVED) {
		printf("WARNING: Attempt to add non-MPSAFE disk %s%d\n",
		    dp->d_name, dp->d_unit);
		printf("WARNING: Ignoring disk %s%d\n",
		    dp->d_name, dp->d_unit);
		return;
	}
	KASSERT(dp->d_strategy != NULL, ("disk_create need d_strategy"));
	KASSERT(dp->d_name != NULL, ("disk_create need d_name"));
	KASSERT(*dp->d_name != 0, ("disk_create need d_name"));
	KASSERT(strlen(dp->d_name) < SPECNAMELEN - 4, ("disk name too long"));
	g_disk_ident_adjust(dp->d_ident, sizeof(dp->d_ident));

	dp->d_init_level = DISK_INIT_CREATE;

	KASSERT(dp->d_cevent != NULL,
	    ("Disk create for %p with event NULL", dp));
	g_post_event_ep(g_disk_create, dp, dp->d_cevent, dp, NULL);
}

void
disk_destroy(struct disk *dp)
{
	struct disk_alias *dap, *daptmp;

	/* If disk_create() was never called, just free the resources. */
	if (dp->d_init_level < DISK_INIT_CREATE) {
		if (dp->d_devstat != NULL)
			devstat_remove_entry(dp->d_devstat);
		LIST_FOREACH_SAFE(dap, &dp->d_aliases, da_next, daptmp)
			g_free(dap);
		g_free(dp->d_cevent);
		g_free(dp->d_devent);
		g_free(dp);
		return;
	}

	KASSERT(dp->d_devent != NULL,
	    ("Disk destroy for %p with event NULL", dp));
	disk_gone(dp);
	dp->d_destroyed = 1;
	g_cancel_event(dp);
	if (dp->d_devstat != NULL)
		devstat_remove_entry(dp->d_devstat);
	g_post_event_ep(g_disk_destroy, dp, dp->d_devent, NULL);
}

void
disk_add_alias(struct disk *dp, const char *name)
{
	struct disk_alias *dap;

	dap = (struct disk_alias *)g_malloc(
		sizeof(struct disk_alias) + strlen(name) + 1, M_WAITOK);
	strcpy((char *)(dap + 1), name);
	dap->da_alias = (const char *)(dap + 1);
	LIST_INSERT_HEAD(&dp->d_aliases, dap, da_next);
}

void
disk_gone(struct disk *dp)
{
	struct g_geom *gp;
	struct g_provider *pp;

	mtx_pool_lock(mtxpool_sleep, dp);

	/*
	 * Second wither call makes no sense, plus we can not access the list
	 * of providers without topology lock after calling wither once.
	 */
	if (dp->d_goneflag != 0) {
		mtx_pool_unlock(mtxpool_sleep, dp);
		return;
	}

	dp->d_goneflag = 1;

	/*
	 * If we're still in the process of creating this disk (the
	 * g_disk_create() function is still queued, or is in
	 * progress), the init level will not yet be DISK_INIT_DONE.
	 *
	 * If that is the case, g_disk_create() will see d_goneflag
	 * and take care of cleaning things up.
	 *
	 * If the disk has already been created, we default to
	 * withering the provider as usual below.
	 *
	 * If the caller has not set a d_gone() callback, he will
	 * not be any worse off by returning here, because the geom
	 * has not been fully setup in any case.
	 */
	if (dp->d_init_level < DISK_INIT_DONE) {
		mtx_pool_unlock(mtxpool_sleep, dp);
		return;
	}
	mtx_pool_unlock(mtxpool_sleep, dp);

	gp = dp->d_geom;
	pp = LIST_FIRST(&gp->provider);
	if (pp != NULL) {
		KASSERT(LIST_NEXT(pp, provider) == NULL,
		    ("geom %p has more than one provider", gp));
		g_wither_provider(pp, ENXIO);
	}
}

void
disk_attr_changed(struct disk *dp, const char *attr, int flag)
{
	struct g_geom *gp = dp->d_geom;
	struct g_provider *pp;
	char devnamebuf[128];

	if (gp == NULL)
		return;
	LIST_FOREACH(pp, &gp->provider, provider)
		(void)g_attr_changed(pp, attr, flag);
	snprintf(devnamebuf, sizeof(devnamebuf), "devname=%s%d", dp->d_name,
	    dp->d_unit);
	devctl_notify("GEOM", "disk", attr, devnamebuf);
}

void
disk_media_changed(struct disk *dp, int flag)
{
	struct g_geom *gp = dp->d_geom;
	struct g_provider *pp;

	if (gp == NULL)
		return;
	pp = LIST_FIRST(&gp->provider);
	if (pp != NULL) {
		KASSERT(LIST_NEXT(pp, provider) == NULL,
		    ("geom %p has more than one provider", gp));
		g_media_changed(pp, flag);
	}
}

void
disk_media_gone(struct disk *dp, int flag)
{
	struct g_geom *gp = dp->d_geom;
	struct g_provider *pp;

	if (gp == NULL)
		return;
	pp = LIST_FIRST(&gp->provider);
	if (pp != NULL) {
		KASSERT(LIST_NEXT(pp, provider) == NULL,
		    ("geom %p has more than one provider", gp));
		g_media_gone(pp, flag);
	}
}

int
disk_resize(struct disk *dp, int flag)
{

	if (dp->d_destroyed || dp->d_geom == NULL)
		return (0);

	return (g_post_event(g_disk_resize, dp, flag, NULL));
}

static void
g_kern_disks(void *p, int flag __unused)
{
	struct sbuf *sb;
	struct g_geom *gp;
	char *sp;

	sb = p;
	sp = "";
	g_topology_assert();
	LIST_FOREACH(gp, &g_disk_class.geom, geom) {
		sbuf_printf(sb, "%s%s", sp, gp->name);
		sp = " ";
	}
	sbuf_finish(sb);
}

static int
g_disk_sysctl_flags(SYSCTL_HANDLER_ARGS)
{
	struct disk *dp;
	struct sbuf *sb;
	int error;

	sb = sbuf_new_auto();
	dp = (struct disk *)arg1;
	sbuf_printf(sb, "%b", dp->d_flags,
		"\20"
		"\2OPEN"
		"\3CANDELETE"
		"\4CANFLUSHCACHE"
		"\5UNMAPPEDBIO"
		"\6DIRECTCOMPLETION"
		"\10CANZONE"
		"\11WRITEPROTECT");

	sbuf_finish(sb);
	error = SYSCTL_OUT(req, sbuf_data(sb), sbuf_len(sb) + 1);
	sbuf_delete(sb);
	return (error);
}

static int
sysctl_disks(SYSCTL_HANDLER_ARGS)
{
	int error;
	struct sbuf *sb;

	sb = sbuf_new_auto();
	g_waitfor_event(g_kern_disks, sb, M_WAITOK, NULL);
	error = SYSCTL_OUT(req, sbuf_data(sb), sbuf_len(sb) + 1);
	sbuf_delete(sb);
	return error;
}

SYSCTL_PROC(_kern, OID_AUTO, disks,
    CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0,
    sysctl_disks, "A", "names of available disks");