GEOM_UNCOMPRESS module, can be used with uzip images and with new ulzma images.

Approved by:	adrian (mentor)

1 files changed, 670 insertions, 0 deletions

diff --git a/sys/geom/uncompress/g_uncompress.c b/sys/geom/uncompress/g_uncompress.c
new file mode 100644
index 0000000..778d5c6
--- /dev/null
+++ b/sys/geom/uncompress/g_uncompress.c
@@ -0,0 +1,670 @@
+/*-
+ * Copyright (c) 2010-2012 Aleksandr Rybalko
+ * Copyright (c) 2004 Max Khon
+ * 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.
+ *
+ * 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.
+ */
+
+/*
+ * GEOM UNCOMPRESS module - simple decompression module for use with read-only
+ * copressed images maked by mkuzip(8) or mkulzma(8) utilities.
+ *
+ * To enable module in kernel config, put this line:
+ * device	geom_uncompress
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/param.h>
+#include <sys/bio.h>
+#include <sys/endian.h>
+#include <sys/errno.h>
+#include <sys/kernel.h>
+#include <sys/lock.h>
+#include <sys/mutex.h>
+#include <sys/malloc.h>
+#include <sys/systm.h>
+
+#include <geom/geom.h>
+
+#include <net/zlib.h>
+#include <contrib/xz-embedded/linux/include/linux/xz.h>
+
+#ifdef GEOM_UNCOMPRESS_DEBUG
+#define	DPRINTF(a)	printf a
+extern int g_debugflags;
+#else
+#define	DPRINTF(a)
+#endif
+
+static MALLOC_DEFINE(M_GEOM_UNCOMPRESS, "geom_uncompress",
+    "GEOM UNCOMPRESS data structures");
+
+#define	UNCOMPRESS_CLASS_NAME	"UNCOMPRESS"
+#define	GEOM_UZIP_MAJVER '2'
+#define	GEOM_ULZMA_MAJVER '3'
+
+/*
+ * Maximum allowed valid block size (to prevent foot-shooting)
+ */
+#define	MAX_BLKSZ	(MAXPHYS)
+
+/*
+ * Integer values (block size, number of blocks, offsets)
+ * are stored in big-endian (network) order on disk and struct cloop_header
+ * and in native order in struct g_uncompress_softc
+ */
+
+#define	CLOOP_MAGIC_LEN	128
+static char CLOOP_MAGIC_START[] = "#!/bin/sh\n";
+
+struct cloop_header {
+	char magic[CLOOP_MAGIC_LEN];	/* cloop magic */
+	uint32_t blksz;			/* block size */
+	uint32_t nblocks;		/* number of blocks */
+};
+
+struct g_uncompress_softc {
+	uint32_t blksz;			/* block size */
+	uint32_t nblocks;		/* number of blocks */
+	uint64_t *offsets;
+	enum {
+		GEOM_UZIP = 1,
+		GEOM_ULZMA
+	} type;
+
+	struct mtx last_mtx;
+	uint32_t last_blk;		/* last blk no */
+	char *last_buf;			/* last blk data */
+	int req_total;			/* total requests */
+	int req_cached;			/* cached requests */
+
+	/* XZ decoder structs */
+	struct xz_buf *b;
+	struct xz_dec *s;
+	z_stream *zs;
+};
+
+static void
+g_uncompress_softc_free(struct g_uncompress_softc *sc, struct g_geom *gp)
+{
+
+	if (gp != NULL) {
+		printf("%s: %d requests, %d cached\n",
+		    gp->name, sc->req_total, sc->req_cached);
+	}
+	if (sc->offsets != NULL) {
+		free(sc->offsets, M_GEOM_UNCOMPRESS);
+		sc->offsets = 0;
+	}
+
+	switch (sc->type) {
+	case GEOM_ULZMA:
+		if (sc->b) {
+			free(sc->b, M_GEOM_UNCOMPRESS);
+			sc->b = 0;
+		}
+		if (sc->s) {
+			xz_dec_end(sc->s);
+			sc->s = 0;
+		}
+		break;
+	case GEOM_UZIP:
+		if (sc->zs) {
+			inflateEnd(sc->zs);
+			free(sc->zs, M_GEOM_UNCOMPRESS);
+			sc->zs = 0;
+		}
+		break;
+	}
+
+	mtx_destroy(&sc->last_mtx);
+	free(sc->last_buf, M_GEOM_UNCOMPRESS);
+	free(sc, M_GEOM_UNCOMPRESS);
+}
+
+static void *
+z_alloc(void *nil, u_int type, u_int size)
+{
+	void *ptr;
+
+	ptr = malloc(type * size, M_GEOM_UNCOMPRESS, M_NOWAIT);
+	return (ptr);
+}
+
+static void
+z_free(void *nil, void *ptr)
+{
+
+	free(ptr, M_GEOM_UNCOMPRESS);
+}
+
+static void
+g_uncompress_done(struct bio *bp)
+{
+	struct g_uncompress_softc *sc;
+	struct g_provider *pp, *pp2;
+	struct g_consumer *cp;
+	struct g_geom *gp;
+	struct bio *bp2;
+	uint32_t start_blk, i;
+	off_t pos, upos;
+	size_t bsize;
+	int err;
+
+	err = 0;
+	bp2 = bp->bio_parent;
+	pp = bp2->bio_to;
+	gp = pp->geom;
+	cp = LIST_FIRST(&gp->consumer);
+	pp2 = cp->provider;
+	sc = gp->softc;
+	DPRINTF(("%s: done\n", gp->name));
+
+	bp2->bio_error = bp->bio_error;
+	if (bp2->bio_error != 0)
+		goto done;
+
+	/*
+	 * Example:
+	 * Uncompressed block size = 65536
+	 * User request: 65540-261632
+	 * (4 uncompressed blocks -4B at start, -512B at end)
+	 *
+	 * We have 512(secsize)*63(nsec) = 32256B at offset 1024
+	 * From:  1024  bp->bio_offset = 1024
+	 * To:   33280  bp->bio_length = 33280 - 1024 = 32256
+	 * Compressed blocks: 0-1020, 1020-1080, 1080-4845, 4845-12444,
+	 * 	12444-33210, 33210-44100, ...
+	 *
+	 * Get start_blk from user request:
+	 * start_blk = bp2->bio_offset / 65536 = 65540/65536 = 1
+	 * bsize (block size of parent) = pp2->sectorsize (Now is 4B)
+	 * pos(in stream from parent) = sc->offsets[start_blk] % bsize =
+	 *    = sc->offsets[1] % 4 = 1020 % 4 = 0
+	 */
+
+	/*
+	 * Uncompress data.
+	 */
+	start_blk = bp2->bio_offset / sc->blksz;
+	bsize = pp2->sectorsize;
+	pos = sc->offsets[start_blk] % bsize;
+	upos = 0;
+
+	DPRINTF(("%s: done: bio_length %lld bio_completed %lld start_blk %d, "
+		"pos %lld, upos %lld (%lld, %d, %d)\n",
+	    gp->name, bp->bio_length, bp->bio_completed, start_blk, pos, upos,
+	    bp2->bio_offset, sc->blksz, bsize));
+
+	for (i = start_blk; upos < bp2->bio_length; i++) {
+		off_t len, dlen, ulen, uoff;
+
+		uoff = i == start_blk ? bp2->bio_offset % sc->blksz : 0;
+		ulen = MIN(sc->blksz - uoff, bp2->bio_length - upos);
+		dlen = len = sc->offsets[i + 1] - sc->offsets[i];
+
+		DPRINTF(("%s: done: inflate block %d, start %lld, end %lld "
+			"len %lld\n",
+		    gp->name, i, sc->offsets[i], sc->offsets[i + 1], len));
+
+		if (len == 0) {
+			/* All zero block: no cache update */
+			bzero(bp2->bio_data + upos, ulen);
+			upos += ulen;
+			bp2->bio_completed += ulen;
+			continue;
+		}
+
+		mtx_lock(&sc->last_mtx);
+
+#ifdef GEOM_UNCOMPRESS_DEBUG
+		if (g_debugflags & 32)
+			hexdump(bp->bio_data + pos, dlen, 0, 0);
+#endif
+
+		switch (sc->type) {
+		case GEOM_ULZMA:
+			sc->b->in = bp->bio_data + pos;
+			sc->b->out = sc->last_buf;
+			sc->b->in_pos = sc->b->out_pos = 0;
+			sc->b->in_size = dlen;
+			sc->b->out_size = (size_t)-1;
+
+			err = (xz_dec_run(sc->s, sc->b) != XZ_STREAM_END) ?
+			    1 : 0;
+			/* TODO decoder recovery, if needed */
+			break;
+		case GEOM_UZIP:
+			sc->zs->next_in = bp->bio_data + pos;
+			sc->zs->avail_in = dlen;
+			sc->zs->next_out = sc->last_buf;
+			sc->zs->avail_out = sc->blksz;
+
+			err = (inflate(sc->zs, Z_FINISH) != Z_STREAM_END) ?
+			    1 : 0;
+			if ((err) && (inflateReset(sc->zs) != Z_OK))
+				printf("%s: UZIP decoder reset failed\n",
+				     gp->name);
+			break;
+		}
+
+		if (err) {
+			sc->last_blk = -1;
+			mtx_unlock(&sc->last_mtx);
+			DPRINTF(("%s: done: inflate failed, code=%d\n",
+			    gp->name, err));
+			bp2->bio_error = EIO;
+			goto done;
+		}
+
+#ifdef GEOM_UNCOMPRESS_DEBUG
+		if (g_debugflags & 32)
+			hexdump(sc->last_buf, sc->b->out_size, 0, 0);
+#endif
+
+		sc->last_blk = i;
+		DPRINTF(("%s: done: inflated \n", gp->name));
+		memcpy(bp2->bio_data + upos, sc->last_buf + uoff, ulen);
+		mtx_unlock(&sc->last_mtx);
+
+		pos += len;
+		upos += ulen;
+		bp2->bio_completed += ulen;
+	}
+
+done:
+	/*
+	 * Finish processing the request.
+	 */
+	DPRINTF(("%s: done: (%d, %lld, %ld)\n",
+	    gp->name, bp2->bio_error, bp2->bio_completed, bp2->bio_resid));
+	free(bp->bio_data, M_GEOM_UNCOMPRESS);
+	g_destroy_bio(bp);
+	g_io_deliver(bp2, bp2->bio_error);
+}
+
+static void
+g_uncompress_start(struct bio *bp)
+{
+	struct g_uncompress_softc *sc;
+	struct g_provider *pp, *pp2;
+	struct g_consumer *cp;
+	struct g_geom *gp;
+	struct bio *bp2;
+	uint32_t start_blk, end_blk;
+	size_t bsize;
+
+
+	pp = bp->bio_to;
+	gp = pp->geom;
+	DPRINTF(("%s: start (%s) to %s off=%lld len=%lld\n", gp->name,
+		(bp->bio_cmd==BIO_READ) ? "BIO_READ" : "BIO_WRITE*",
+		pp->name, bp->bio_offset, bp->bio_length));
+
+	if (bp->bio_cmd != BIO_READ) {
+		g_io_deliver(bp, EOPNOTSUPP);
+		return;
+	}
+
+	cp = LIST_FIRST(&gp->consumer);
+	pp2 = cp->provider;
+	sc = gp->softc;
+
+	start_blk = bp->bio_offset / sc->blksz;
+	end_blk   = howmany(bp->bio_offset + bp->bio_length, sc->blksz);
+	KASSERT(start_blk < sc->nblocks,
+		("start_blk out of range"));
+	KASSERT(end_blk <= sc->nblocks,
+		("end_blk out of range"));
+
+	sc->req_total++;
+	if (start_blk + 1 == end_blk) {
+		mtx_lock(&sc->last_mtx);
+		if (start_blk == sc->last_blk) {
+			off_t uoff;
+
+			uoff = bp->bio_offset % sc->blksz;
+			KASSERT(bp->bio_length <= sc->blksz - uoff,
+			    ("cached data error"));
+			memcpy(bp->bio_data, sc->last_buf + uoff,
+			    bp->bio_length);
+			sc->req_cached++;
+			mtx_unlock(&sc->last_mtx);
+
+			DPRINTF(("%s: start: cached 0 + %lld, "
+			    "%lld + 0 + %lld\n",
+			    gp->name, bp->bio_length, uoff, bp->bio_length));
+			bp->bio_completed = bp->bio_length;
+			g_io_deliver(bp, 0);
+			return;
+		}
+		mtx_unlock(&sc->last_mtx);
+	}
+
+	bp2 = g_clone_bio(bp);
+	if (bp2 == NULL) {
+		g_io_deliver(bp, ENOMEM);
+		return;
+	}
+	DPRINTF(("%s: start (%d..%d), %s: %d + %llu, %s: %d + %llu\n",
+	    gp->name, start_blk, end_blk,
+	    pp->name, pp->sectorsize, pp->mediasize,
+	    pp2->name, pp2->sectorsize, pp2->mediasize));
+
+	bsize = pp2->sectorsize;
+
+	bp2->bio_done = g_uncompress_done;
+	bp2->bio_offset = rounddown(sc->offsets[start_blk],bsize);
+	bp2->bio_length = roundup(sc->offsets[end_blk],bsize) -
+	    bp2->bio_offset;
+	bp2->bio_data = malloc(bp2->bio_length, M_GEOM_UNCOMPRESS, M_NOWAIT);
+
+	DPRINTF(("%s: start %lld + %lld -> %lld + %lld -> %lld + %lld\n",
+	    gp->name,
+	    bp->bio_offset, bp->bio_length,
+	    sc->offsets[start_blk],
+	    sc->offsets[end_blk] - sc->offsets[start_blk],
+	    bp2->bio_offset, bp2->bio_length));
+
+	if (bp2->bio_data == NULL) {
+		g_destroy_bio(bp2);
+		g_io_deliver(bp, ENOMEM);
+		return;
+	}
+
+	g_io_request(bp2, cp);
+	DPRINTF(("%s: start ok\n", gp->name));
+}
+
+static void
+g_uncompress_orphan(struct g_consumer *cp)
+{
+	struct g_geom *gp;
+
+	g_trace(G_T_TOPOLOGY, "%s(%p/%s)", __func__, cp,
+		cp->provider->name);
+	g_topology_assert();
+	KASSERT(cp->provider->error != 0,
+		("g_uncompress_orphan with error == 0"));
+
+	gp = cp->geom;
+	g_uncompress_softc_free(gp->softc, gp);
+	gp->softc = NULL;
+	g_wither_geom(gp, cp->provider->error);
+}
+
+static int
+g_uncompress_access(struct g_provider *pp, int dr, int dw, int de)
+{
+	struct g_consumer *cp;
+	struct g_geom *gp;
+
+	gp = pp->geom;
+	cp = LIST_FIRST(&gp->consumer);
+	KASSERT (cp != NULL, ("g_uncompress_access but no consumer"));
+
+	if (cp->acw + dw > 0)
+		return (EROFS);
+
+	return (g_access(cp, dr, dw, de));
+}
+
+static void
+g_uncompress_spoiled(struct g_consumer *cp)
+{
+	struct g_geom *gp;
+
+	gp = cp->geom;
+	g_trace(G_T_TOPOLOGY, "%s(%p/%s)", __func__, cp, gp->name);
+	g_topology_assert();
+
+	g_uncompress_softc_free(gp->softc, gp);
+	gp->softc = NULL;
+	g_wither_geom(gp, ENXIO);
+}
+
+static struct g_geom *
+g_uncompress_taste(struct g_class *mp, struct g_provider *pp, int flags)
+{
+	struct cloop_header *header;
+	struct g_uncompress_softc *sc;
+	struct g_provider *pp2;
+	struct g_consumer *cp;
+	struct g_geom *gp;
+	uint32_t i, total_offsets, offsets_read, type;
+	uint8_t *buf;
+	int error;
+
+	g_trace(G_T_TOPOLOGY, "%s(%s,%s)", __func__, mp->name, pp->name);
+	g_topology_assert();
+
+	/* Skip providers that are already open for writing. */
+	if (pp->acw > 0)
+		return (NULL);
+
+	buf = NULL;
+
+	/*
+	 * Create geom instance.
+	 */
+	gp = g_new_geomf(mp, "%s.uncompress", pp->name);
+	cp = g_new_consumer(gp);
+	error = g_attach(cp, pp);
+	if (error == 0)
+		error = g_access(cp, 1, 0, 0);
+	if (error) {
+		g_detach(cp);
+		g_destroy_consumer(cp);
+		g_destroy_geom(gp);
+		return (NULL);
+	}
+	g_topology_unlock();
+
+	/*
+	 * Read cloop header, look for CLOOP magic, perform
+	 * other validity checks.
+	 */
+	DPRINTF(("%s: media sectorsize %u, mediasize %lld\n",
+	    gp->name, pp->sectorsize, pp->mediasize));
+
+	i = roundup(sizeof(struct cloop_header), pp->sectorsize);
+	buf = g_read_data(cp, 0, i, NULL);
+	if (buf == NULL)
+		goto err;
+
+	header = (struct cloop_header *) buf;
+	if (strncmp(header->magic, CLOOP_MAGIC_START,
+		    sizeof(CLOOP_MAGIC_START) - 1) != 0) {
+		DPRINTF(("%s: no CLOOP magic\n", gp->name));
+		goto err;
+	}
+
+	switch (header->magic[0x0b]) {
+	case 'L':
+		type = GEOM_ULZMA;
+		if (header->magic[0x0c] < GEOM_ULZMA_MAJVER) {
+			DPRINTF(("%s: image version too old\n", gp->name));
+			goto err;
+		}
+		printf("%s: GEOM_ULZMA image found\n", gp->name);
+		break;
+	case 'V':
+		type = GEOM_UZIP;
+		if (header->magic[0x0c] < GEOM_UZIP_MAJVER) {
+			DPRINTF(("%s: image version too old\n", gp->name));
+			goto err;
+		}
+		printf("%s: GEOM_UZIP image found\n", gp->name);
+		break;
+	default:
+		DPRINTF(("%s: unsupported image type\n", gp->name));
+		goto err;
+	}
+
+	DPRINTF(("%s: found CLOOP magic\n", gp->name));
+	/*
+	 * Initialize softc and read offsets.
+	 */
+	sc = malloc(sizeof(*sc), M_GEOM_UNCOMPRESS, M_WAITOK | M_ZERO);
+	gp->softc = sc;
+	sc->type = type;
+	sc->blksz = ntohl(header->blksz);
+	sc->nblocks = ntohl(header->nblocks);
+	if (sc->blksz % 4 != 0) {
+		printf("%s: block size (%u) should be multiple of 4.\n",
+		    gp->name, sc->blksz);
+		goto err;
+	}
+	if (sc->blksz > MAX_BLKSZ) {
+		printf("%s: block size (%u) should not be larger than %d.\n",
+		    gp->name, sc->blksz, MAX_BLKSZ);
+	}
+	total_offsets = sc->nblocks + 1;
+	if (sizeof(struct cloop_header) +
+	    total_offsets * sizeof(uint64_t) > pp->mediasize) {
+		printf("%s: media too small for %u blocks\n",
+		    gp->name, sc->nblocks);
+		goto err;
+	}
+	sc->offsets = malloc(
+	    total_offsets * sizeof(uint64_t), M_GEOM_UNCOMPRESS, M_WAITOK);
+	offsets_read = MIN(total_offsets,
+	    (pp->sectorsize - sizeof(*header)) / sizeof(uint64_t));
+	for (i = 0; i < offsets_read; i++)
+		sc->offsets[i] = be64toh(((uint64_t *) (header + 1))[i]);
+	DPRINTF(("%s: %u offsets in the first sector\n",
+	    gp->name, offsets_read));
+
+	free(buf, M_GEOM);
+	i = roundup((sizeof(struct cloop_header) +
+		total_offsets * sizeof(uint64_t)),pp->sectorsize);
+	buf = g_read_data(cp, 0, i, NULL);
+	if (buf == NULL)
+		goto err;
+	for (i = 0; i <= total_offsets; i++) {
+		sc->offsets[i] = be64toh(((uint64_t *)
+		    (buf+sizeof(struct cloop_header)))[i]);
+	}
+	DPRINTF(("%s: done reading offsets\n", gp->name));
+	mtx_init(&sc->last_mtx, "geom_uncompress cache", NULL, MTX_DEF);
+	sc->last_blk = -1;
+	sc->last_buf = malloc(sc->blksz, M_GEOM_UNCOMPRESS, M_WAITOK);
+	sc->req_total = 0;
+	sc->req_cached = 0;
+
+	switch (sc->type) {
+	case GEOM_ULZMA:
+		xz_crc32_init();
+		sc->s = xz_dec_init(XZ_SINGLE, 0);
+		sc->b = (struct xz_buf*)malloc(sizeof(struct xz_buf),
+		    M_GEOM_UNCOMPRESS, M_WAITOK);
+		break;
+	case GEOM_UZIP:
+		sc->zs = (z_stream *)malloc(sizeof(z_stream),
+		    M_GEOM_UNCOMPRESS, M_WAITOK);
+		sc->zs->zalloc = z_alloc;
+		sc->zs->zfree = z_free;
+		if (inflateInit(sc->zs) != Z_OK) {
+			goto err;
+		}
+		break;
+	}
+
+	g_topology_lock();
+	pp2 = g_new_providerf(gp, "%s", gp->name);
+	pp2->sectorsize = 512;
+	pp2->mediasize = (off_t)sc->nblocks * sc->blksz;
+	pp2->flags = pp->flags & G_PF_CANDELETE;
+	if (pp->stripesize > 0) {
+		pp2->stripesize = pp->stripesize;
+		pp2->stripeoffset = pp->stripeoffset;
+	}
+	g_error_provider(pp2, 0);
+	free(buf, M_GEOM);
+	g_access(cp, -1, 0, 0);
+
+	DPRINTF(("%s: taste ok (%d, %lld), (%d, %d), %x\n",
+	    gp->name,
+	    pp2->sectorsize, pp2->mediasize,
+	    pp2->stripeoffset, pp2->stripesize, pp2->flags));
+	printf("%s: %u x %u blocks\n",
+	    gp->name, sc->nblocks, sc->blksz);
+	return (gp);
+
+err:
+	g_topology_lock();
+	g_access(cp, -1, 0, 0);
+	if (buf != NULL)
+		free(buf, M_GEOM);
+	if (gp->softc != NULL) {
+		g_uncompress_softc_free(gp->softc, NULL);
+		gp->softc = NULL;
+	}
+	g_detach(cp);
+	g_destroy_consumer(cp);
+	g_destroy_geom(gp);
+	return (NULL);
+}
+
+static int
+g_uncompress_destroy_geom(struct gctl_req *req, struct g_class *mp,
+			  struct g_geom *gp)
+{
+	struct g_provider *pp;
+
+	g_trace(G_T_TOPOLOGY, "%s(%s, %s)", __func__, mp->name, gp->name);
+	g_topology_assert();
+
+	if (gp->softc == NULL) {
+		printf("%s(%s): gp->softc == NULL\n", __func__, gp->name);
+		return (ENXIO);
+	}
+
+	KASSERT(gp != NULL, ("NULL geom"));
+	pp = LIST_FIRST(&gp->provider);
+	KASSERT(pp != NULL, ("NULL provider"));
+	if (pp->acr > 0 || pp->acw > 0 || pp->ace > 0)
+		return (EBUSY);
+
+	g_uncompress_softc_free(gp->softc, gp);
+	gp->softc = NULL;
+	g_wither_geom(gp, ENXIO);
+	return (0);
+}
+
+static struct g_class g_uncompress_class = {
+	.name = UNCOMPRESS_CLASS_NAME,
+	.version = G_VERSION,
+	.taste = g_uncompress_taste,
+	.destroy_geom = g_uncompress_destroy_geom,
+
+	.start = g_uncompress_start,
+	.orphan = g_uncompress_orphan,
+	.access = g_uncompress_access,
+	.spoiled = g_uncompress_spoiled,
+};
+
+DECLARE_GEOM_CLASS(g_uncompress_class, g_uncompress);
+