Improve mkuzip(8) and geom_uzip(4), merge in LZMA support from mkulzma(8)

and geom_uncompress(4):

1. mkuzip(8):

 - Proper support for eliminating all-zero blocks when compressing an
   image. This feature is already supported by the geom_uzip(4) module
   and CLOOP format in general, so it's just a matter of making mkuzip(8)
   match. It should be noted, however that this feature while it sounds
   great, results in very slight improvement in the overall compression
   ratio, since compressing default 16k all-zero block produces only 39
   bytes compressed output block, which is 99.8% compression ratio. With
   typical average compression ratio of amd64 binaries and data being
   around 60-70% the difference between 99.8% and 100.0% is not that
   great further diluted by the ratio of number of zero blocks in the
   uncompressed image to the overall number of blocks being less than
   0.5 (typically). However, this may be important from performance
   standpoint, so that kernel are not spinning its wheels decompressing
   those empty blocks every time this zero region is read. It could also
   be important when you create huge image mostly filled with zero
   blocks for testing purposes.

 - New feature allowing to de-duplicate output image. It turns out that
   if you twist CLOOP format a bit you can do that as well. And unlike
   zero-blocks elimination, this gives a noticeable improvement in the
   overall compression ratio, reducing output image by something like
   3-4% on my test UFS2 3GB image consisting of full FreeBSD base system
   plus some of the packages (openjdk, apache etc), about 2.3GB worth of
   file data (800+MB compressed). The only caveat is that images created
   with this feature "on" would not work on older versions of FeeBSDxi
   kernel, hence it's turned off by default.

 - provide options to control both features and document them in manual
   page.

 - merge in all relevant LZMA compression support from the mkulzma(8),
   add new option to select between both.

 - switch license from ad-hoc beerware into standard 2-clause BSD.

2. geom_uzip(4):

 - implement support for de-duplicated images;

 - optimize some code paths to handle "all-zero" blocks without reading
   any compressed data;

 - beef up manual page to explain that geom_uzip(4) is not limited only
   to md(4) images. The compressed data can be written to the block
   device and accessed directly via magic of GEOM(4) and devfs(4),
   including to mount root fs from a compressed drive.

 - convert debug log code from being compiled in conditionally into
   being present all the time and provide two sysctls to turn it on or
   off. Due to intended use of the module, it can be used in
   environments where there may not be a luxury to put new kernel with
   debug code enabled. Having those options handy allows debug issues
   without as much problem by just having access to serial console or
   network shell access to a box/appliance. The resulting additional
   CPU cycles are just few int comparisons and branches, and those are
   minuscule when compared to data decompression which is the main
   feature of the module.

 - hopefully improve robustness and resiliency of the geom_uzip(4) by
   performing some of the data validation / range checking on the TOC
   entries and rejecting to attach to an image if those checks fail.

 - merge in all relevant LZMA decompression support from the
   geom_uncompress(4), enable automatically when appropriate format is
   indicated in the header.

 - move compilation work into its own worker thread so that it does not
   clog g_up. This allows multiple instances work in parallel utilizing
   smp cores.

 - document new knobs in the manual page.

Reviewed by:		adrian
MFC after:		1 month
Differential Revision:	https://reviews.freebsd.org/D5333

11 files changed, 985 insertions, 143 deletions

diff --git a/sys/geom/uzip/g_uzip.c b/sys/geom/uzip/g_uzip.c
index 8363d06..17d179b 100644
--- a/sys/geom/uzip/g_uzip.c
+++ b/sys/geom/uzip/g_uzip.c
@@ -1,6 +1,7 @@
 /*-
  * Copyright (c) 2004 Max Khon
  * Copyright (c) 2014 Juniper Networks, Inc.
+ * Copyright (c) 2006-2016 Maxim Sobolev <sobomax@FreeBSD.org>
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -38,91 +39,116 @@ __FBSDID("$FreeBSD$");
 #include <sys/malloc.h>
 #include <sys/sysctl.h>
 #include <sys/systm.h>
-#include <sys/zlib.h>
+#include <sys/kthread.h>
 
 #include <geom/geom.h>
 
-FEATURE(geom_uzip, "GEOM uzip read-only compressed disks support");
+MALLOC_DEFINE(M_GEOM_UZIP, "geom_uzip", "GEOM UZIP data structures");
+
+#include <geom/uzip/g_uzip.h>
+#include <geom/uzip/g_uzip_cloop.h>
+#include <geom/uzip/g_uzip_softc.h>
+#include <geom/uzip/g_uzip_dapi.h>
+#include <geom/uzip/g_uzip_zlib.h>
+#include <geom/uzip/g_uzip_lzma.h>
+#include <geom/uzip/g_uzip_wrkthr.h>
+
+FEATURE(geom_uzip, "GEOM read-only compressed disks support");
+
+struct g_uzip_blk {
+        uint64_t offset;
+        uint32_t blen;
+#define BLEN_UNDEF      UINT32_MAX
+};
+
+#ifndef ABS
+#define	ABS(a)			((a) < 0 ? -(a) : (a))
+#endif
+
+#define BLK_IN_RANGE(mcn, bcn, ilen)	\
+    (((bcn) != BLEN_UNDEF) && ( \
+	((ilen) >= 0 && (mcn >= bcn) && (mcn <= ((intmax_t)(bcn) + (ilen)))) || \
+	((ilen) < 0 && (mcn <= bcn) && (mcn >= ((intmax_t)(bcn) + (ilen)))) \
+    ))
 
-#undef GEOM_UZIP_DEBUG
 #ifdef GEOM_UZIP_DEBUG
-#define	DPRINTF(a)	printf a
+# define GEOM_UZIP_DBG_DEFAULT	3
 #else
-#define	DPRINTF(a)
+# define GEOM_UZIP_DBG_DEFAULT	0
 #endif
 
-static MALLOC_DEFINE(M_GEOM_UZIP, "geom_uzip", "GEOM UZIP data structures");
+#define	GUZ_DBG_ERR	1
+#define	GUZ_DBG_INFO	2
+#define	GUZ_DBG_IO	3
+#define	GUZ_DBG_TOC	4
+
+SYSCTL_DECL(_kern_geom);
+SYSCTL_NODE(_kern_geom, OID_AUTO, uzip, CTLFLAG_RW, 0, "GEOM_UZIP stuff");
+static u_int g_uzip_debug = GEOM_UZIP_DBG_DEFAULT;
+SYSCTL_UINT(_kern_geom_uzip, OID_AUTO, debug, CTLFLAG_RWTUN, &g_uzip_debug, 0,
+    "Debug level (0-4)");
+static u_int g_uzip_debug_block = BLEN_UNDEF;
+SYSCTL_UINT(_kern_geom_uzip, OID_AUTO, debug_block, CTLFLAG_RWTUN,
+    &g_uzip_debug_block, 0, "Debug operations around specific cluster#");
+
+#define	DPRINTF(lvl, a)		\
+	if ((lvl) <= g_uzip_debug) { \
+		printf a; \
+	}
+#define	DPRINTF_BLK(lvl, cn, a)	\
+	if ((lvl) <= g_uzip_debug || \
+	    BLK_IN_RANGE(cn, g_uzip_debug_block, 8) || \
+	    BLK_IN_RANGE(cn, g_uzip_debug_block, -8)) { \
+		printf a; \
+	}
+#define	DPRINTF_BRNG(lvl, bcn, ecn, a) \
+	if (bcn >= ecn) { \
+		printf("DPRINTF_BRNG: invalid range (%ju, %ju), BUG BUG " \
+		    "BUG!\n", (uintmax_t)bcn, (uintmax_t)ecn); \
+	} else if (((lvl) <= g_uzip_debug) || \
+	    BLK_IN_RANGE(g_uzip_debug_block, bcn, \
+	     (intmax_t)ecn - (intmax_t)bcn)) { \
+		printf a; \
+	}
 
 #define	UZIP_CLASS_NAME	"UZIP"
 
 /*
  * Maximum allowed valid block size (to prevent foot-shooting)
  */
-#define	MAX_BLKSZ	(MAXPHYS - MAXPHYS / 1000 - 12)
+#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_uzip_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_uzip_softc {
-	uint32_t blksz;			/* block size */
-	uint32_t nblocks;		/* number of blocks */
-	uint64_t *offsets;
-
-	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 */
-};
-
-static void g_uzip_done(struct bio *bp);
+static void g_uzip_read_done(struct bio *bp);
+static void g_uzip_do(struct g_uzip_softc *, struct bio *bp);
 
 static void
 g_uzip_softc_free(struct g_uzip_softc *sc, struct g_geom *gp)
 {
 
 	if (gp != NULL) {
-		DPRINTF(("%s: %d requests, %d cached\n",
+		DPRINTF(GUZ_DBG_INFO, ("%s: %d requests, %d cached\n",
 		    gp->name, sc->req_total, sc->req_cached));
 	}
-	if (sc->offsets != NULL) {
-		free(sc->offsets, M_GEOM_UZIP);
-		sc->offsets = NULL;
+
+	mtx_lock(&sc->queue_mtx);
+	sc->wrkthr_flags |= GUZ_SHUTDOWN;
+	wakeup(sc);
+	while (!(sc->wrkthr_flags & GUZ_EXITING)) {
+		msleep(sc->procp, &sc->queue_mtx, PRIBIO, "guzfree",
+		    hz / 10);
 	}
+	mtx_unlock(&sc->queue_mtx);
+
+	sc->dcp->free(sc->dcp);
+	free(sc->toc, M_GEOM_UZIP);
+	mtx_destroy(&sc->queue_mtx);
 	mtx_destroy(&sc->last_mtx);
 	free(sc->last_buf, M_GEOM_UZIP);
 	free(sc, M_GEOM_UZIP);
 }
 
-static void *
-z_alloc(void *nil, u_int type, u_int size)
-{
-	void *ptr;
-
-	ptr = malloc(type * size, M_GEOM_UZIP, M_NOWAIT);
-
-	return (ptr);
-}
-
-static void
-z_free(void *nil, void *ptr)
-{
-
-	free(ptr, M_GEOM_UZIP);
-}
-
 static int
 g_uzip_cached(struct g_geom *gp, struct bio *bp)
 {
@@ -144,8 +170,9 @@ g_uzip_cached(struct g_geom *gp, struct bio *bp)
 		sc->req_cached++;
 		mtx_unlock(&sc->last_mtx);
 
-		DPRINTF(("%s/%s: %p: offset=%jd: got %jd bytes from cache\n",
-		    __func__, gp->name, bp, (intmax_t)ofs, (intmax_t)usz));
+		DPRINTF(GUZ_DBG_IO, ("%s/%s: %p: offset=%jd: got %jd bytes "
+		    "from cache\n", __func__, gp->name, bp, (intmax_t)ofs,
+		    (intmax_t)usz));
 
 		bp->bio_completed += usz;
 		bp->bio_resid -= usz;
@@ -160,6 +187,19 @@ g_uzip_cached(struct g_geom *gp, struct bio *bp)
 	return (0);
 }
 
+#define BLK_ENDS(sc, bi)	((sc)->toc[(bi)].offset + \
+    (sc)->toc[(bi)].blen)
+
+#define BLK_IS_CONT(sc, bi)	(BLK_ENDS((sc), (bi) - 1) == \
+    (sc)->toc[(bi)].offset)
+#define	BLK_IS_NIL(sc, bi)	((sc)->toc[(bi)].blen == 0)
+
+#define TOFF_2_BOFF(sc, pp, bi)	    ((sc)->toc[(bi)].offset - \
+    (sc)->toc[(bi)].offset % (pp)->sectorsize)
+#define TLEN_2_BLEN(sc, pp, bp, ei) ((BLK_ENDS((sc), (ei)) - \
+    (bp)->bio_offset + (pp)->sectorsize - 1) / \
+    (pp)->sectorsize * (pp)->sectorsize)
+
 static int
 g_uzip_request(struct g_geom *gp, struct bio *bp)
 {
@@ -167,21 +207,14 @@ g_uzip_request(struct g_geom *gp, struct bio *bp)
 	struct bio *bp2;
 	struct g_consumer *cp;
 	struct g_provider *pp;
-	off_t ofs;
-	size_t start_blk, end_blk;
+	off_t ofs, start_blk_ofs;
+	size_t i, start_blk, end_blk, zsize;
 
 	if (g_uzip_cached(gp, bp) != 0)
 		return (1);
 
 	sc = gp->softc;
 
-	bp2 = g_clone_bio(bp);
-	if (bp2 == NULL) {
-		g_io_deliver(bp, ENOMEM);
-		return (1);
-	}
-	bp2->bio_done = g_uzip_done;
-
 	cp = LIST_FIRST(&gp->consumer);
 	pp = cp->provider;
 
@@ -191,17 +224,54 @@ g_uzip_request(struct g_geom *gp, struct bio *bp)
 	end_blk = (ofs + bp->bio_resid + sc->blksz - 1) / sc->blksz;
 	KASSERT(end_blk <= sc->nblocks, ("end_blk out of range"));
 
-	DPRINTF(("%s/%s: %p: start=%u (%jd), end=%u (%jd)\n",
-	    __func__, gp->name, bp,
-	    (u_int)start_blk, (intmax_t)sc->offsets[start_blk],
-	    (u_int)end_blk, (intmax_t)sc->offsets[end_blk]));
+	for (; BLK_IS_NIL(sc, start_blk) && start_blk < end_blk; start_blk++) {
+		/* Fill in any leading Nil blocks */
+		start_blk_ofs = ofs % sc->blksz;
+		zsize = MIN(sc->blksz - start_blk_ofs, bp->bio_resid);
+		DPRINTF_BLK(GUZ_DBG_IO, start_blk, ("%s/%s: %p/%ju: "
+		    "filling %ju zero bytes\n", __func__, gp->name, gp,
+		    (uintmax_t)bp->bio_completed, (uintmax_t)zsize));
+		bzero(bp->bio_data + bp->bio_completed, zsize);
+		bp->bio_completed += zsize;
+		bp->bio_resid -= zsize;
+		ofs += zsize;
+	}
+
+	if (start_blk == end_blk) {
+		KASSERT(bp->bio_resid == 0, ("bp->bio_resid is invalid"));
+		/*
+		 * No non-Nil data is left, complete request immediately.
+		 */
+		DPRINTF(GUZ_DBG_IO, ("%s/%s: %p: all done returning %ju "
+		    "bytes\n", __func__, gp->name, gp,
+		    (uintmax_t)bp->bio_completed));
+		g_io_deliver(bp, 0);
+		return (1);
+	}
+
+	for (i = start_blk + 1; i < end_blk; i++) {
+		/* Trim discontinuous areas if any */
+		if (!BLK_IS_CONT(sc, i)) {
+			end_blk = i;
+			break;
+		}
+	}
+
+	DPRINTF_BRNG(GUZ_DBG_IO, start_blk, end_blk, ("%s/%s: %p: "
+	    "start=%u (%ju), end=%u (%ju)\n", __func__, gp->name, bp,
+	    (u_int)start_blk, (uintmax_t)sc->toc[start_blk].offset,
+	    (u_int)end_blk, (uintmax_t)BLK_ENDS(sc, end_blk - 1)));
+
+	bp2 = g_clone_bio(bp);
+	if (bp2 == NULL) {
+		g_io_deliver(bp, ENOMEM);
+		return (1);
+	}
+	bp2->bio_done = g_uzip_read_done;
 
-	bp2->bio_offset = sc->offsets[start_blk] - 
-	    sc->offsets[start_blk] % pp->sectorsize;
+	bp2->bio_offset = TOFF_2_BOFF(sc, pp, start_blk);
 	while (1) {
-		bp2->bio_length = sc->offsets[end_blk] - bp2->bio_offset;
-		bp2->bio_length = (bp2->bio_length + pp->sectorsize - 1) /
-		    pp->sectorsize * pp->sectorsize;
+		bp2->bio_length = TLEN_2_BLEN(sc, pp, bp2, end_blk - 1);
 		if (bp2->bio_length <= MAXPHYS)
 			break;
 
@@ -215,8 +285,8 @@ g_uzip_request(struct g_geom *gp, struct bio *bp)
 		return (1);
 	}
 
-	DPRINTF(("%s/%s: %p: reading %jd bytes from offset %jd\n",
-	    __func__, gp->name, bp,
+	DPRINTF_BRNG(GUZ_DBG_IO, start_blk, end_blk, ("%s/%s: %p: "
+	    "reading %jd bytes from offset %jd\n", __func__, gp->name, bp,
 	    (intmax_t)bp2->bio_length, (intmax_t)bp2->bio_offset));
 
 	g_io_request(bp2, cp);
@@ -224,21 +294,36 @@ g_uzip_request(struct g_geom *gp, struct bio *bp)
 }
 
 static void
-g_uzip_done(struct bio *bp)
+g_uzip_read_done(struct bio *bp)
+{
+	struct bio *bp2;
+	struct g_geom *gp;
+	struct g_uzip_softc *sc;
+
+	bp2 = bp->bio_parent;
+	gp = bp2->bio_to->geom;
+	sc = gp->softc;
+
+	mtx_lock(&sc->queue_mtx);
+	bioq_disksort(&sc->bio_queue, bp);
+	mtx_unlock(&sc->queue_mtx);
+	wakeup(sc);
+}
+
+static void
+g_uzip_do(struct g_uzip_softc *sc, struct bio *bp)
 {
-	z_stream zs;
 	struct bio *bp2;
 	struct g_provider *pp;
 	struct g_consumer *cp;
 	struct g_geom *gp;
-	struct g_uzip_softc *sc;
 	char *data, *data2;
 	off_t ofs;
-	size_t blk, blkofs, len, ulen;
+	size_t blk, blkofs, len, ulen, firstblk;
+	int err;
 
 	bp2 = bp->bio_parent;
 	gp = bp2->bio_to->geom;
-	sc = gp->softc;
 
 	cp = LIST_FIRST(&gp->consumer);
 	pp = cp->provider;
@@ -253,46 +338,47 @@ g_uzip_done(struct bio *bp)
 		goto done;
 	}
 
-	zs.zalloc = z_alloc;
-	zs.zfree = z_free;
-	if (inflateInit(&zs) != Z_OK) {
-		bp2->bio_error = EILSEQ;
-		goto done;
-	}
-
 	ofs = bp2->bio_offset + bp2->bio_completed;
-	blk = ofs / sc->blksz;
+	firstblk = blk = ofs / sc->blksz;
 	blkofs = ofs % sc->blksz;
-	data = bp->bio_data + sc->offsets[blk] % pp->sectorsize;
+	data = bp->bio_data + sc->toc[blk].offset % pp->sectorsize;
 	data2 = bp2->bio_data + bp2->bio_completed;
 	while (bp->bio_completed && bp2->bio_resid) {
+		if (blk > firstblk && !BLK_IS_CONT(sc, blk)) {
+			DPRINTF_BLK(GUZ_DBG_IO, blk, ("%s/%s: %p: backref'ed "
+			    "cluster #%u requested, looping around\n",
+			    __func__, gp->name, bp2, (u_int)blk));
+			goto done;
+		}
 		ulen = MIN(sc->blksz - blkofs, bp2->bio_resid);
-		len = sc->offsets[blk + 1] - sc->offsets[blk];
-		DPRINTF(("%s/%s: %p/%ju: data2=%p, ulen=%u, data=%p, len=%u\n",
-		    __func__, gp->name, gp, bp->bio_completed,
-		    data2, (u_int)ulen, data, (u_int)len));
+		len = sc->toc[blk].blen;
+		DPRINTF(GUZ_DBG_IO, ("%s/%s: %p/%ju: data2=%p, ulen=%u, "
+		    "data=%p, len=%u\n", __func__, gp->name, gp,
+		    bp->bio_completed, data2, (u_int)ulen, data, (u_int)len));
 		if (len == 0) {
 			/* All zero block: no cache update */
 			bzero(data2, ulen);
 		} else if (len <= bp->bio_completed) {
-			zs.next_in = data;
-			zs.avail_in = len;
-			zs.next_out = sc->last_buf;
-			zs.avail_out = sc->blksz;
 			mtx_lock(&sc->last_mtx);
-			if (inflate(&zs, Z_FINISH) != Z_STREAM_END) {
+			err = sc->dcp->decompress(sc->dcp, gp->name, data,
+			    len, sc->last_buf);
+			if (err != 0) {
 				sc->last_blk = -1;
 				mtx_unlock(&sc->last_mtx);
-				inflateEnd(&zs);
 				bp2->bio_error = EILSEQ;
+				DPRINTF(GUZ_DBG_ERR, ("%s/%s: decompress"
+				    "(%p) failed\n", __func__, gp->name,
+				    sc->dcp));
 				goto done;
 			}
 			sc->last_blk = blk;
 			memcpy(data2, sc->last_buf + blkofs, ulen);
 			mtx_unlock(&sc->last_mtx);
-			if (inflateReset(&zs) != Z_OK) {
-				inflateEnd(&zs);
+			err = sc->dcp->rewind(sc->dcp, gp->name);
+			if (err != 0) {
 				bp2->bio_error = EILSEQ;
+				DPRINTF(GUZ_DBG_ERR, ("%s/%s: rewind(%p) "
+				    "failed\n", __func__, gp->name, sc->dcp));
 				goto done;
 			}
 			data += len;
@@ -307,9 +393,6 @@ g_uzip_done(struct bio *bp)
 		blk++;
 	}
 
-	if (inflateEnd(&zs) != Z_OK)
-		bp2->bio_error = EILSEQ;
-
 done:
 	/* Finish processing the request. */
 	free(bp->bio_data, M_GEOM_UZIP);
@@ -330,9 +413,9 @@ g_uzip_start(struct bio *bp)
 	pp = bp->bio_to;
 	gp = pp->geom;
 
-	DPRINTF(("%s/%s: %p: cmd=%d, offset=%jd, length=%jd, buffer=%p\n",
-	    __func__, gp->name, bp, bp->bio_cmd, (intmax_t)bp->bio_offset,
-	    (intmax_t)bp->bio_length, bp->bio_data));
+	DPRINTF(GUZ_DBG_IO, ("%s/%s: %p: cmd=%d, offset=%jd, length=%jd, "
+	    "buffer=%p\n", __func__, gp->name, bp, bp->bio_cmd,
+	    (intmax_t)bp->bio_offset, (intmax_t)bp->bio_length, bp->bio_data));
 
 	sc = gp->softc;
 	sc->req_total++;
@@ -392,6 +475,92 @@ g_uzip_spoiled(struct g_consumer *cp)
 	g_wither_geom(gp, ENXIO);
 }
 
+static int
+g_uzip_parse_toc(struct g_uzip_softc *sc, struct g_provider *pp,
+    struct g_geom *gp)
+{
+	uint32_t i, j, backref_to;
+	uint64_t max_offset, min_offset;
+
+	min_offset = sizeof(struct cloop_header) +
+	    (sc->nblocks + 1) * sizeof(uint64_t);
+	max_offset = sc->toc[0].offset - 1;
+	for (i = 0; i < sc->nblocks; i++) {
+		/* First do some bounds checking */
+		if ((sc->toc[i].offset < min_offset) ||
+		    (sc->toc[i].offset >= pp->mediasize)) {
+			goto error_offset;
+		}
+		DPRINTF_BLK(GUZ_DBG_IO, i, ("%s: cluster #%u "
+		    "sc->toc[i].offset=%ju max_offset=%ju\n", gp->name,
+		    (u_int)i, (uintmax_t)sc->toc[i].offset,
+		    (uintmax_t)max_offset));
+		backref_to = BLEN_UNDEF;
+		if (sc->toc[i].offset < max_offset) {
+			/*
+			 * For the backref'ed blocks search already parsed
+			 * TOC entries for the matching offset and copy the
+			 * size from matched entry.
+			 */
+			for (j = 0; j <= i; j++) {
+                                if (sc->toc[j].offset == sc->toc[i].offset &&
+				    !BLK_IS_NIL(sc, j)) {
+                                        break;
+                                }
+                                if (j != i) {
+					continue;
+				}
+				DPRINTF(GUZ_DBG_ERR, ("%s: cannot match "
+				    "backref'ed offset at cluster #%u\n",
+				    gp->name, i));
+				return (-1);
+			}
+			sc->toc[i].blen = sc->toc[j].blen;
+			backref_to = j;
+		} else {
+			/*
+			 * For the "normal blocks" seek forward until we hit
+			 * block whose offset is larger than ours and assume
+			 * it's going to be the next one.
+			 */
+			for (j = i + 1; j < sc->nblocks; j++) {
+				if (sc->toc[j].offset > max_offset) {
+					break;
+				}
+			}
+			sc->toc[i].blen = sc->toc[j].offset -
+			    sc->toc[i].offset;
+			if (BLK_ENDS(sc, i) > pp->mediasize) {
+				DPRINTF(GUZ_DBG_ERR, ("%s: cluster #%u "
+				    "extends past media boundary (%ju > %ju)\n",
+				    gp->name, (u_int)i,
+				    (uintmax_t)BLK_ENDS(sc, i),
+				    (intmax_t)pp->mediasize));
+				return (-1);
+			}
+			KASSERT(max_offset <= sc->toc[i].offset, (
+			    "%s: max_offset is incorrect: %ju",
+			    gp->name, (uintmax_t)max_offset));
+			max_offset = BLK_ENDS(sc, i) - 1;
+		}
+		DPRINTF_BLK(GUZ_DBG_TOC, i, ("%s: cluster #%u, original %u "
+		    "bytes, in %u bytes", gp->name, i, sc->blksz,
+		    sc->toc[i].blen));
+		if (backref_to != BLEN_UNDEF) {
+			DPRINTF_BLK(GUZ_DBG_TOC, i, (" (->#%u)",
+			    (u_int)backref_to));
+		}
+		DPRINTF_BLK(GUZ_DBG_TOC, i, ("\n"));
+	}
+	return (0);
+
+error_offset:
+	DPRINTF(GUZ_DBG_ERR, ("%s: cluster #%u: invalid offset %ju, "
+	    "min_offset=%ju mediasize=%jd\n", gp->name, (u_int)i,
+	    sc->toc[i].offset, min_offset, pp->mediasize));
+	return (-1);
+}
+
 static struct g_geom *
 g_uzip_taste(struct g_class *mp, struct g_provider *pp, int flags)
 {
@@ -403,6 +572,10 @@ g_uzip_taste(struct g_class *mp, struct g_provider *pp, int flags)
 	struct g_geom *gp;
 	struct g_provider *pp2;
 	struct g_uzip_softc *sc;
+	enum {
+		GEOM_UZIP = 1,
+		GEOM_ULZMA
+	} type;
 
 	g_trace(G_T_TOPOLOGY, "%s(%s,%s)", __func__, mp->name, pp->name);
 	g_topology_assert();
@@ -422,10 +595,7 @@ g_uzip_taste(struct g_class *mp, struct g_provider *pp, int flags)
 	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);
+		goto e1;
 	}
 	g_topology_unlock();
 
@@ -433,22 +603,47 @@ g_uzip_taste(struct g_class *mp, struct g_provider *pp, int flags)
 	 * Read cloop header, look for CLOOP magic, perform
 	 * other validity checks.
 	 */
-	DPRINTF(("%s: media sectorsize %u, mediasize %jd\n",
+	DPRINTF(GUZ_DBG_INFO, ("%s: media sectorsize %u, mediasize %jd\n",
 	    gp->name, pp->sectorsize, (intmax_t)pp->mediasize));
 	buf = g_read_data(cp, 0, pp->sectorsize, NULL);
 	if (buf == NULL)
-		goto err;
+		goto e2;
 	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;
-	}
-	if (header->magic[0x0b] != 'V' || header->magic[0x0c] < '2') {
-		DPRINTF(("%s: image version too old\n", gp->name));
-		goto err;
+		DPRINTF(GUZ_DBG_ERR, ("%s: no CLOOP magic\n", gp->name));
+		goto e3;
 	}
 
+	switch (header->magic[CLOOP_OFS_COMPR]) {
+	case CLOOP_COMP_LZMA:
+	case CLOOP_COMP_LZMA_DDP:
+		type = GEOM_ULZMA;
+		if (header->magic[CLOOP_OFS_VERSN] < CLOOP_MINVER_LZMA) {
+			DPRINTF(GUZ_DBG_ERR, ("%s: image version too old\n",
+			    gp->name));
+			goto e3;
+		}
+		DPRINTF(GUZ_DBG_INFO, ("%s: GEOM_UZIP_LZMA image found\n",
+		    gp->name));
+		break;
+	case CLOOP_COMP_LIBZ:
+	case CLOOP_COMP_LIBZ_DDP:
+		type = GEOM_UZIP;
+		if (header->magic[CLOOP_OFS_VERSN] < CLOOP_MINVER_ZLIB) {
+			DPRINTF(GUZ_DBG_ERR, ("%s: image version too old\n",
+			    gp->name));
+			goto e3;
+		}
+		DPRINTF(GUZ_DBG_INFO, ("%s: GEOM_UZIP_ZLIB image found\n",
+		    gp->name));
+		break;
+	default:
+		DPRINTF(GUZ_DBG_ERR, ("%s: unsupported image type\n",
+		    gp->name));
+                goto e3;
+        }
+
 	/*
 	 * Initialize softc and read offsets.
 	 */
@@ -459,7 +654,7 @@ g_uzip_taste(struct g_class *mp, struct g_provider *pp, int flags)
 	if (sc->blksz % 512 != 0) {
 		printf("%s: block size (%u) should be multiple of 512.\n",
 		    gp->name, sc->blksz);
-		goto err;
+		goto e4;
 	}
 	if (sc->blksz > MAX_BLKSZ) {
 		printf("%s: block size (%u) should not be larger than %d.\n",
@@ -470,15 +665,17 @@ g_uzip_taste(struct g_class *mp, struct g_provider *pp, int flags)
 	    total_offsets * sizeof(uint64_t) > pp->mediasize) {
 		printf("%s: media too small for %u blocks\n",
 		    gp->name, sc->nblocks);
-		goto err;
+		goto e4;
 	}
-	sc->offsets = malloc(
-	    total_offsets * sizeof(uint64_t), M_GEOM_UZIP, M_WAITOK);
+	sc->toc = malloc(total_offsets * sizeof(struct g_uzip_blk),
+	    M_GEOM_UZIP, M_WAITOK | M_ZERO);
 	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",
+	for (i = 0; i < offsets_read; i++) {
+		sc->toc[i].offset = be64toh(((uint64_t *) (header + 1))[i]);
+		sc->toc[i].blen = BLEN_UNDEF;
+	}
+	DPRINTF(GUZ_DBG_INFO, ("%s: %u offsets in the first sector\n",
 	       gp->name, offsets_read));
 	for (blk = 1; offsets_read < total_offsets; blk++) {
 		uint32_t nread;
@@ -487,25 +684,59 @@ g_uzip_taste(struct g_class *mp, struct g_provider *pp, int flags)
 		buf = g_read_data(
 		    cp, blk * pp->sectorsize, pp->sectorsize, NULL);
 		if (buf == NULL)
-			goto err;
+			goto e5;
 		nread = MIN(total_offsets - offsets_read,
 		     pp->sectorsize / sizeof(uint64_t));
-		DPRINTF(("%s: %u offsets read from sector %d\n",
+		DPRINTF(GUZ_DBG_TOC, ("%s: %u offsets read from sector %d\n",
 		    gp->name, nread, blk));
 		for (i = 0; i < nread; i++) {
-			sc->offsets[offsets_read + i] =
+			sc->toc[offsets_read + i].offset =
 			    be64toh(((uint64_t *) buf)[i]);
+			sc->toc[offsets_read + i].blen = BLEN_UNDEF;
 		}
 		offsets_read += nread;
 	}
 	free(buf, M_GEOM);
-	DPRINTF(("%s: done reading offsets\n", gp->name));
+	buf = NULL;
+	offsets_read -= 1;
+	DPRINTF(GUZ_DBG_INFO, ("%s: done reading %u block offsets from %u "
+	    "sectors\n", gp->name, offsets_read, blk));
+	if (sc->nblocks != offsets_read) {
+		DPRINTF(GUZ_DBG_ERR, ("%s: read %s offsets than expected "
+		    "blocks\n", gp->name,
+		    sc->nblocks < offsets_read ? "more" : "less"));
+		goto e5;
+	}
+	/* Massage TOC (table of contents), make sure it is sound */
+	if (g_uzip_parse_toc(sc, pp, gp) != 0) {
+		DPRINTF(GUZ_DBG_ERR, ("%s: TOC error\n", gp->name));
+		goto e5;
+	}
 	mtx_init(&sc->last_mtx, "geom_uzip cache", NULL, MTX_DEF);
+	mtx_init(&sc->queue_mtx, "geom_uzip wrkthread", NULL, MTX_DEF);
+	bioq_init(&sc->bio_queue);
 	sc->last_blk = -1;
 	sc->last_buf = malloc(sc->blksz, M_GEOM_UZIP, M_WAITOK);
 	sc->req_total = 0;
 	sc->req_cached = 0;
 
+	if (type == GEOM_UZIP) {
+		sc->dcp = g_uzip_zlib_ctor(sc->blksz);
+	} else {
+		sc->dcp = g_uzip_lzma_ctor(sc->blksz);
+	}
+	if (sc->dcp == NULL) {
+		goto e6;
+	}
+
+	sc->uzip_do = &g_uzip_do;
+
+	error = kproc_create(g_uzip_wrkthr, sc, &sc->procp, 0, 0, "%s",
+	    gp->name);
+	if (error != 0) {
+		goto e7;
+	}
+
 	g_topology_lock();
 	pp2 = g_new_providerf(gp, "%s", gp->name);
 	pp2->sectorsize = 512;
@@ -515,22 +746,31 @@ g_uzip_taste(struct g_class *mp, struct g_provider *pp, int flags)
 	g_error_provider(pp2, 0);
 	g_access(cp, -1, 0, 0);
 
-	DPRINTF(("%s: taste ok (%d, %jd), (%d, %d), %x\n",
-	    gp->name,
-	    pp2->sectorsize, (intmax_t)pp2->mediasize,
+	DPRINTF(GUZ_DBG_INFO, ("%s: taste ok (%d, %jd), (%d, %d), %x\n",
+	    gp->name, pp2->sectorsize, (intmax_t)pp2->mediasize,
 	    pp2->stripeoffset, pp2->stripesize, pp2->flags));
-	DPRINTF(("%s: %u x %u blocks\n", gp->name, sc->nblocks, sc->blksz));
+	DPRINTF(GUZ_DBG_INFO, ("%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)
+e7:
+	sc->dcp->free(sc->dcp);
+e6:
+	free(sc->last_buf, M_GEOM);
+	mtx_destroy(&sc->queue_mtx);
+	mtx_destroy(&sc->last_mtx);
+e5:
+	free(sc->toc, M_GEOM);
+e4:
+	free(gp->softc, M_GEOM_UZIP);
+e3:
+	if (buf != NULL) {
 		free(buf, M_GEOM);
-	if (gp->softc != NULL) {
-		g_uzip_softc_free(gp->softc, NULL);
-		gp->softc = NULL;
 	}
+e2:
+	g_topology_lock();
+	g_access(cp, -1, 0, 0);
+e1:
 	g_detach(cp);
 	g_destroy_consumer(cp);
 	g_destroy_geom(gp);
@@ -547,7 +787,8 @@ g_uzip_destroy_geom(struct gctl_req *req, struct g_class *mp, struct g_geom *gp)
 	g_topology_assert();
 
 	if (gp->softc == NULL) {
-		DPRINTF(("%s(%s): gp->softc == NULL\n", __func__, gp->name));
+		DPRINTF(GUZ_DBG_ERR, ("%s(%s): gp->softc == NULL\n", __func__,
+		    gp->name));
 		return (ENXIO);
 	}
 
diff --git a/sys/geom/uzip/g_uzip.h b/sys/geom/uzip/g_uzip.h
new file mode 100644
index 0000000..7a16827
--- /dev/null
+++ b/sys/geom/uzip/g_uzip.h
@@ -0,0 +1,35 @@
+/*-
+ * Copyright (c) 2004 Max Khon
+ * Copyright (c) 2014 Juniper Networks, Inc.
+ * Copyright (c) 2006-2016 Maxim Sobolev <sobomax@FreeBSD.org>
+ * 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.
+ *
+ * $FreeBSD$
+ */
+
+#if !defined(M_GEOM_UZIP)
+MALLOC_DECLARE(M_GEOM_UZIP);
+#endif
+
+#define DEFINE_RAW_METHOD(func, rval, args...) typedef rval (*func##_t)(args)
diff --git a/sys/geom/uzip/g_uzip_cloop.h b/sys/geom/uzip/g_uzip_cloop.h
new file mode 100644
index 0000000..219a7b6
--- /dev/null
+++ b/sys/geom/uzip/g_uzip_cloop.h
@@ -0,0 +1,55 @@
+/*
+ * Copyright (c) 2004-2016 Maxim Sobolev <sobomax@FreeBSD.org>
+ * 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.
+ *
+ * $FreeBSD$
+ */
+
+/* CLOOP format and related constants */
+
+/*
+ * Integer values (block size, number of blocks, offsets)
+ * are stored in big-endian (network) order on disk.
+ */
+
+#define CLOOP_MAGIC_LEN 128
+#define CLOOP_OFS_COMPR 0x0b
+#define CLOOP_OFS_VERSN (CLOOP_OFS_COMPR + 1)
+
+#define CLOOP_MAJVER_2	'2'
+#define CLOOP_MAJVER_3	'3'
+
+#define	CLOOP_COMP_LIBZ		'V'
+#define	CLOOP_COMP_LIBZ_DDP	'v'
+#define	CLOOP_COMP_LZMA		'L'
+#define	CLOOP_COMP_LZMA_DDP	'l'
+
+#define	CLOOP_MINVER_LZMA	CLOOP_MAJVER_3
+#define	CLOOP_MINVER_ZLIB	CLOOP_MAJVER_2
+
+struct cloop_header {
+        char magic[CLOOP_MAGIC_LEN];    /* cloop magic */
+        uint32_t blksz;                 /* block size */
+        uint32_t nblocks;               /* number of blocks */
+};
diff --git a/sys/geom/uzip/g_uzip_dapi.h b/sys/geom/uzip/g_uzip_dapi.h
new file mode 100644
index 0000000..0689c32
--- /dev/null
+++ b/sys/geom/uzip/g_uzip_dapi.h
@@ -0,0 +1,41 @@
+/*-
+ * Copyright (c) 2006-2016 Maxim Sobolev <sobomax@FreeBSD.org>
+ * 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.
+ *
+ * $FreeBSD$
+ */
+
+struct g_uzip_dapi;
+
+DEFINE_RAW_METHOD(g_uzip_dapi_decompress, int, struct g_uzip_dapi *,
+    const char *, void *, size_t, void *);
+DEFINE_RAW_METHOD(g_uzip_dapi_free, void, struct g_uzip_dapi *);
+DEFINE_RAW_METHOD(g_uzip_dapi_rewind, int, struct g_uzip_dapi *, const char *);
+
+struct g_uzip_dapi {
+	g_uzip_dapi_decompress_t decompress;
+	g_uzip_dapi_free_t free;
+	g_uzip_dapi_rewind_t rewind;
+	void *pvt;
+};
diff --git a/sys/geom/uzip/g_uzip_lzma.c b/sys/geom/uzip/g_uzip_lzma.c
new file mode 100644
index 0000000..0a981ba
--- /dev/null
+++ b/sys/geom/uzip/g_uzip_lzma.c
@@ -0,0 +1,111 @@
+/*-
+ * Copyright (c) 2004 Max Khon
+ * Copyright (c) 2014 Juniper Networks, Inc.
+ * Copyright (c) 2006-2016 Maxim Sobolev <sobomax@FreeBSD.org>
+ * Copyright (c) 2010-2012 Aleksandr Rybalko
+ * 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.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/types.h>
+#include <sys/malloc.h>
+
+#include <contrib/xz-embedded/linux/include/linux/xz.h>
+
+#include <geom/uzip/g_uzip.h>
+#include <geom/uzip/g_uzip_dapi.h>
+#include <geom/uzip/g_uzip_lzma.h>
+
+struct g_uzip_lzma {
+	struct g_uzip_dapi pub;
+	/* XZ decoder structs */
+	struct xz_buf b;
+	struct xz_dec *s;
+};
+
+static int g_uzip_lzma_nop(struct g_uzip_dapi *, const char *);
+
+static void
+g_uzip_lzma_free(struct g_uzip_dapi *lzpp)
+{
+	struct g_uzip_lzma *lzp;
+
+	lzp = (struct g_uzip_lzma *)lzpp->pvt;
+	if (lzp->s != NULL) {
+		xz_dec_end(lzp->s);
+		lzp->s = NULL;
+	}
+
+	free(lzp, M_GEOM_UZIP);
+}
+
+static int
+g_uzip_lzma_decompress(struct g_uzip_dapi *lzpp, const char *gp_name,
+    void *ibp, size_t ilen, void *obp)
+{
+	struct g_uzip_lzma *lzp;
+	int err;
+
+	lzp = (struct g_uzip_lzma *)lzpp->pvt;
+
+	lzp->b.in = ibp;
+	lzp->b.out = obp;
+	lzp->b.in_pos = lzp->b.out_pos = 0;
+	lzp->b.in_size = ilen;
+	lzp->b.out_size = (size_t)-1;
+	err = (xz_dec_run(lzp->s, &lzp->b) != XZ_STREAM_END) ? 1 : 0;
+	/* TODO decoder recovery, if needed */
+
+	return (err);
+}
+
+struct g_uzip_dapi *
+g_uzip_lzma_ctor(uint32_t blksz)
+{
+	struct g_uzip_lzma *lzp;
+
+	lzp = malloc(sizeof(struct g_uzip_lzma), M_GEOM_UZIP, M_WAITOK);
+	xz_crc32_init();
+	lzp->s = xz_dec_init(XZ_SINGLE, 0);
+	if (lzp->s == NULL) {
+		goto e1;
+	}
+	lzp->pub.decompress = &g_uzip_lzma_decompress;
+	lzp->pub.free = &g_uzip_lzma_free;
+	lzp->pub.rewind = &g_uzip_lzma_nop;
+	lzp->pub.pvt = lzp;
+	return (&lzp->pub);
+e1:
+        free(lzp, M_GEOM_UZIP);
+        return (NULL);
+}
+
+static int
+g_uzip_lzma_nop(struct g_uzip_dapi *zpp, const char *gp_name)
+{
+
+        return (0);
+}
diff --git a/sys/geom/uzip/g_uzip_lzma.h b/sys/geom/uzip/g_uzip_lzma.h
new file mode 100644
index 0000000..f9f8a27
--- /dev/null
+++ b/sys/geom/uzip/g_uzip_lzma.h
@@ -0,0 +1,32 @@
+/*-
+ * Copyright (c) 2004 Max Khon
+ * Copyright (c) 2014 Juniper Networks, Inc.
+ * Copyright (c) 2006-2016 Maxim Sobolev <sobomax@FreeBSD.org>
+ * Copyright (c) 2010-2012 Aleksandr Rybalko
+ * 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.
+ *
+ * $FreeBSD$
+ */
+
+struct g_uzip_dapi *g_uzip_lzma_ctor(uint32_t);
diff --git a/sys/geom/uzip/g_uzip_softc.h b/sys/geom/uzip/g_uzip_softc.h
new file mode 100644
index 0000000..1d12ac0
--- /dev/null
+++ b/sys/geom/uzip/g_uzip_softc.h
@@ -0,0 +1,56 @@
+/*-
+ * Copyright (c) 2004 Max Khon
+ * Copyright (c) 2014 Juniper Networks, Inc.
+ * Copyright (c) 2006-2016 Maxim Sobolev <sobomax@FreeBSD.org>
+ * 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.
+ *
+ * $FreeBSD$
+ */
+
+struct g_uzip_softc;
+struct bio;
+
+DEFINE_RAW_METHOD(g_uzip_do, void, struct g_uzip_softc *, struct bio *);
+
+struct g_uzip_softc {
+	uint32_t blksz;                 /* block size */
+	uint32_t nblocks;               /* number of blocks */
+	struct g_uzip_blk *toc;         /* table of contents */
+
+	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 */
+	struct g_uzip_dapi *dcp;        /* decompressor instance */
+
+	g_uzip_do_t uzip_do;
+
+	struct proc *procp;
+	struct bio_queue_head bio_queue; 
+	struct mtx queue_mtx;
+	unsigned wrkthr_flags;
+#define	GUZ_SHUTDOWN	(0x1 << 0)
+#define	GUZ_EXITING	(0x1 << 1)
+};
diff --git a/sys/geom/uzip/g_uzip_wrkthr.c b/sys/geom/uzip/g_uzip_wrkthr.c
new file mode 100644
index 0000000..ad24cb8
--- /dev/null
+++ b/sys/geom/uzip/g_uzip_wrkthr.c
@@ -0,0 +1,71 @@
+/*-
+ * Copyright (c) 2006-2016 Maxim Sobolev <sobomax@FreeBSD.org>
+ * 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.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/types.h>
+#include <sys/param.h>
+#include <sys/lock.h>
+#include <sys/mutex.h>
+#include <sys/bio.h>
+#include <sys/proc.h>
+#include <sys/sched.h>
+#include <sys/kthread.h>
+#include <sys/malloc.h>
+
+#include <geom/uzip/g_uzip.h>
+#include <geom/uzip/g_uzip_softc.h>
+#include <geom/uzip/g_uzip_wrkthr.h>
+
+void
+g_uzip_wrkthr(void *arg)
+{
+	struct g_uzip_softc *sc;
+	struct bio *bp;
+
+	sc = (struct g_uzip_softc *)arg;
+	thread_lock(curthread);
+	sched_prio(curthread, PRIBIO);
+	thread_unlock(curthread);
+
+	for (;;) {
+		mtx_lock(&sc->queue_mtx);
+		if (sc->wrkthr_flags & GUZ_SHUTDOWN) {
+			sc->wrkthr_flags |= GUZ_EXITING;
+			mtx_unlock(&sc->queue_mtx);
+			kproc_exit(0);
+		}
+		bp = bioq_takefirst(&sc->bio_queue);
+		if (!bp) {
+			msleep(sc, &sc->queue_mtx, PRIBIO | PDROP,
+			    "wrkwait", 0);
+			continue;
+		}
+		mtx_unlock(&sc->queue_mtx);
+		sc->uzip_do(sc, bp);
+	}
+}
diff --git a/sys/geom/uzip/g_uzip_wrkthr.h b/sys/geom/uzip/g_uzip_wrkthr.h
new file mode 100644
index 0000000..8492378
--- /dev/null
+++ b/sys/geom/uzip/g_uzip_wrkthr.h
@@ -0,0 +1,30 @@
+/*-
+ * Copyright (c) 2006-2016 Maxim Sobolev <sobomax@FreeBSD.org>
+ * 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.
+ *
+ * $FreeBSD$
+ */
+
+void g_uzip_wrkthr(void *);
+
diff --git a/sys/geom/uzip/g_uzip_zlib.c b/sys/geom/uzip/g_uzip_zlib.c
new file mode 100644
index 0000000..cecac6e
--- /dev/null
+++ b/sys/geom/uzip/g_uzip_zlib.c
@@ -0,0 +1,137 @@
+/*-
+ * Copyright (c) 2004 Max Khon
+ * Copyright (c) 2014 Juniper Networks, Inc.
+ * Copyright (c) 2006-2016 Maxim Sobolev <sobomax@FreeBSD.org>
+ * 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.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/types.h>
+#include <sys/systm.h>
+#include <sys/malloc.h>
+
+#include <sys/zlib.h>
+
+#include <geom/uzip/g_uzip.h>
+#include <geom/uzip/g_uzip_dapi.h>
+#include <geom/uzip/g_uzip_zlib.h>
+
+struct g_uzip_zlib {
+	uint32_t blksz;
+	struct g_uzip_dapi pub;
+	/* Zlib decoder structs */
+	z_stream zs;
+};
+
+static void *z_alloc(void *, u_int, u_int);
+static void z_free(void *, void *);
+static int g_uzip_zlib_rewind(struct g_uzip_dapi *, const char *);
+
+static void
+g_uzip_zlib_free(struct g_uzip_dapi *zpp)
+{
+	struct g_uzip_zlib *zp;
+
+	zp = (struct g_uzip_zlib *)zpp->pvt;
+	inflateEnd(&zp->zs);
+	free(zp, M_GEOM_UZIP);
+}
+
+static int
+g_uzip_zlib_decompress(struct g_uzip_dapi *zpp, const char *gp_name, void *ibp,
+    size_t ilen, void *obp)
+{
+	int err;
+	struct g_uzip_zlib *zp;
+
+	zp = (struct g_uzip_zlib *)zpp->pvt;
+
+	zp->zs.next_in = ibp;
+	zp->zs.avail_in = ilen;
+	zp->zs.next_out = obp;
+	zp->zs.avail_out = zp->blksz;
+
+	err = (inflate(&zp->zs, Z_FINISH) != Z_STREAM_END) ? 1 : 0;
+	if (err != 0) {
+		printf("%s: UZIP(zlib) inflate() failed\n", gp_name);
+	}
+	return (err);
+}
+
+static int
+g_uzip_zlib_rewind(struct g_uzip_dapi *zpp, const char *gp_name)
+{
+	int err;
+	struct g_uzip_zlib *zp;
+
+	zp = (struct g_uzip_zlib *)zpp->pvt;
+
+	err = 0;
+	if (inflateReset(&zp->zs) != Z_OK) {
+		printf("%s: UZIP(zlib) decoder reset failed\n", gp_name);
+		err = 1;
+	}
+	return (err);
+}
+
+struct g_uzip_dapi *
+g_uzip_zlib_ctor(uint32_t blksz)
+{
+	struct g_uzip_zlib *zp;
+
+	zp = malloc(sizeof(struct g_uzip_zlib), M_GEOM_UZIP, M_WAITOK);
+	zp->zs.zalloc = z_alloc;
+	zp->zs.zfree = z_free;
+	if (inflateInit(&zp->zs) != Z_OK) {
+		goto e1;
+	}
+	zp->blksz = blksz;
+	zp->pub.decompress = &g_uzip_zlib_decompress;
+	zp->pub.free = &g_uzip_zlib_free;
+	zp->pub.rewind = &g_uzip_zlib_rewind;
+	zp->pub.pvt = (void *)zp;
+	return (&zp->pub);
+e1:
+	free(zp, M_GEOM_UZIP);
+	return (NULL);
+}
+
+static void *
+z_alloc(void *nil, u_int type, u_int size)
+{
+        void *ptr;
+
+        ptr = malloc(type * size, M_GEOM_UZIP, M_NOWAIT);
+
+        return (ptr);
+}
+
+static void
+z_free(void *nil, void *ptr)
+{
+
+        free(ptr, M_GEOM_UZIP);
+}
diff --git a/sys/geom/uzip/g_uzip_zlib.h b/sys/geom/uzip/g_uzip_zlib.h
new file mode 100644
index 0000000..7a767b8
--- /dev/null
+++ b/sys/geom/uzip/g_uzip_zlib.h
@@ -0,0 +1,33 @@
+/*-
+ * Copyright (c) 2004 Max Khon
+ * Copyright (c) 2014 Juniper Networks, Inc.
+ * Copyright (c) 2006-2016 Maxim Sobolev <sobomax@FreeBSD.org>
+ * 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.
+ *
+ * $FreeBSD$
+ */
+
+struct g_geom;
+
+struct g_uzip_dapi *g_uzip_zlib_ctor(uint32_t);