Adding upstream version 18.2.2.upstream/18.2.2

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

4 files changed, 1384 insertions, 0 deletions

diff --git a/src/spdk/test/unit/lib/reduce/Makefile b/src/spdk/test/unit/lib/reduce/Makefile
new file mode 100644
index 000000000..7c901ac18
--- /dev/null
+++ b/src/spdk/test/unit/lib/reduce/Makefile
@@ -0,0 +1,44 @@
+#
+#  BSD LICENSE
+#
+#  Copyright (c) Intel Corporation.
+#  All rights reserved.
+#
+#  Redistribution and use in source and binary forms, with or without
+#  modification, are permitted provided that the following conditions
+#  are met:
+#
+#    * Redistributions of source code must retain the above copyright
+#      notice, this list of conditions and the following disclaimer.
+#    * 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.
+#    * Neither the name of Intel Corporation nor the names of its
+#      contributors may be used to endorse or promote products derived
+#      from this software without specific prior written permission.
+#
+#  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT
+#  OWNER 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.
+#
+
+SPDK_ROOT_DIR := $(abspath $(CURDIR)/../../../..)
+include $(SPDK_ROOT_DIR)/mk/spdk.common.mk
+
+DIRS-y = reduce.c
+
+.PHONY: all clean $(DIRS-y)
+
+all: $(DIRS-y)
+clean: $(DIRS-y)
+
+include $(SPDK_ROOT_DIR)/mk/spdk.subdirs.mk
diff --git a/src/spdk/test/unit/lib/reduce/reduce.c/.gitignore b/src/spdk/test/unit/lib/reduce/reduce.c/.gitignore
new file mode 100644
index 000000000..be248403f
--- /dev/null
+++ b/src/spdk/test/unit/lib/reduce/reduce.c/.gitignore
@@ -0,0 +1 @@
+reduce_ut
diff --git a/src/spdk/test/unit/lib/reduce/reduce.c/Makefile b/src/spdk/test/unit/lib/reduce/reduce.c/Makefile
new file mode 100644
index 000000000..4a704c660
--- /dev/null
+++ b/src/spdk/test/unit/lib/reduce/reduce.c/Makefile
@@ -0,0 +1,39 @@
+#
+#  BSD LICENSE
+#
+#  Copyright (c) Intel Corporation.
+#  All rights reserved.
+#
+#  Redistribution and use in source and binary forms, with or without
+#  modification, are permitted provided that the following conditions
+#  are met:
+#
+#    * Redistributions of source code must retain the above copyright
+#      notice, this list of conditions and the following disclaimer.
+#    * 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.
+#    * Neither the name of Intel Corporation nor the names of its
+#      contributors may be used to endorse or promote products derived
+#      from this software without specific prior written permission.
+#
+#  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT
+#  OWNER 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.
+#
+
+SPDK_ROOT_DIR := $(abspath $(CURDIR)/../../../../..)
+
+TEST_FILE = reduce_ut.c
+LDFLAGS += -Wl,--wrap,unlink
+
+include $(SPDK_ROOT_DIR)/mk/spdk.unittest.mk
diff --git a/src/spdk/test/unit/lib/reduce/reduce.c/reduce_ut.c b/src/spdk/test/unit/lib/reduce/reduce.c/reduce_ut.c
new file mode 100644
index 000000000..9c94a4ac6
--- /dev/null
+++ b/src/spdk/test/unit/lib/reduce/reduce.c/reduce_ut.c
@@ -0,0 +1,1300 @@
+/*-
+ *   BSD LICENSE
+ *
+ *   Copyright (c) Intel Corporation.
+ *   All rights reserved.
+ *
+ *   Redistribution and use in source and binary forms, with or without
+ *   modification, are permitted provided that the following conditions
+ *   are met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * 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.
+ *     * Neither the name of Intel Corporation nor the names of its
+ *       contributors may be used to endorse or promote products derived
+ *       from this software without specific prior written permission.
+ *
+ *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT
+ *   OWNER 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 "spdk/stdinc.h"
+
+#include "spdk_cunit.h"
+
+#include "reduce/reduce.c"
+#include "spdk_internal/mock.h"
+#include "common/lib/test_env.c"
+
+static struct spdk_reduce_vol *g_vol;
+static int g_reduce_errno;
+static char *g_volatile_pm_buf;
+static size_t g_volatile_pm_buf_len;
+static char *g_persistent_pm_buf;
+static size_t g_persistent_pm_buf_len;
+static char *g_backing_dev_buf;
+static char g_path[REDUCE_PATH_MAX];
+static char *g_decomp_buf;
+
+#define TEST_MD_PATH "/tmp"
+
+enum ut_reduce_bdev_io_type {
+	UT_REDUCE_IO_READV = 1,
+	UT_REDUCE_IO_WRITEV = 2,
+	UT_REDUCE_IO_UNMAP = 3,
+};
+
+struct ut_reduce_bdev_io {
+	enum ut_reduce_bdev_io_type type;
+	struct spdk_reduce_backing_dev *backing_dev;
+	struct iovec *iov;
+	int iovcnt;
+	uint64_t lba;
+	uint32_t lba_count;
+	struct spdk_reduce_vol_cb_args *args;
+	TAILQ_ENTRY(ut_reduce_bdev_io)	link;
+};
+
+static bool g_defer_bdev_io = false;
+static TAILQ_HEAD(, ut_reduce_bdev_io) g_pending_bdev_io =
+	TAILQ_HEAD_INITIALIZER(g_pending_bdev_io);
+static uint32_t g_pending_bdev_io_count = 0;
+
+static void
+sync_pm_buf(const void *addr, size_t length)
+{
+	uint64_t offset = (char *)addr - g_volatile_pm_buf;
+
+	memcpy(&g_persistent_pm_buf[offset], addr, length);
+}
+
+int
+pmem_msync(const void *addr, size_t length)
+{
+	sync_pm_buf(addr, length);
+	return 0;
+}
+
+void
+pmem_persist(const void *addr, size_t len)
+{
+	sync_pm_buf(addr, len);
+}
+
+static void
+get_pm_file_size(void)
+{
+	struct spdk_reduce_vol_params params;
+	uint64_t pm_size, expected_pm_size;
+
+	params.backing_io_unit_size = 4096;
+	params.chunk_size = 4096 * 4;
+	params.vol_size = 4096 * 4 * 100;
+
+	pm_size = _get_pm_file_size(&params);
+	expected_pm_size = sizeof(struct spdk_reduce_vol_superblock);
+	/* 100 chunks in logical map * 8 bytes per chunk */
+	expected_pm_size += 100 * sizeof(uint64_t);
+	/* 100 chunks * (chunk stuct size + 4 backing io units per chunk * 8 bytes per backing io unit) */
+	expected_pm_size += 100 * (sizeof(struct spdk_reduce_chunk_map) + 4 * sizeof(uint64_t));
+	/* reduce allocates some extra chunks too for in-flight writes when logical map
+	 * is full.  REDUCE_EXTRA_CHUNKS is a private #ifdef in reduce.c Here we need the num chunks
+	 * times (chunk struct size + 4 backing io units per chunk * 8 bytes per backing io unit).
+	 */
+	expected_pm_size += REDUCE_NUM_EXTRA_CHUNKS *
+			    (sizeof(struct spdk_reduce_chunk_map) + 4 * sizeof(uint64_t));
+	/* reduce will add some padding so numbers may not match exactly.  Make sure
+	 * they are close though.
+	 */
+	CU_ASSERT((pm_size - expected_pm_size) <= REDUCE_PM_SIZE_ALIGNMENT);
+}
+
+static void
+get_vol_size(void)
+{
+	uint64_t chunk_size, backing_dev_size;
+
+	chunk_size = 16 * 1024;
+	backing_dev_size = 16 * 1024 * 1000;
+	CU_ASSERT(_get_vol_size(chunk_size, backing_dev_size) < backing_dev_size);
+}
+
+void *
+pmem_map_file(const char *path, size_t len, int flags, mode_t mode,
+	      size_t *mapped_lenp, int *is_pmemp)
+{
+	CU_ASSERT(g_volatile_pm_buf == NULL);
+	snprintf(g_path, sizeof(g_path), "%s", path);
+	*is_pmemp = 1;
+
+	if (g_persistent_pm_buf == NULL) {
+		g_persistent_pm_buf = calloc(1, len);
+		g_persistent_pm_buf_len = len;
+		SPDK_CU_ASSERT_FATAL(g_persistent_pm_buf != NULL);
+	}
+
+	*mapped_lenp = g_persistent_pm_buf_len;
+	g_volatile_pm_buf = calloc(1, g_persistent_pm_buf_len);
+	SPDK_CU_ASSERT_FATAL(g_volatile_pm_buf != NULL);
+	memcpy(g_volatile_pm_buf, g_persistent_pm_buf, g_persistent_pm_buf_len);
+	g_volatile_pm_buf_len = g_persistent_pm_buf_len;
+
+	return g_volatile_pm_buf;
+}
+
+int
+pmem_unmap(void *addr, size_t len)
+{
+	CU_ASSERT(addr == g_volatile_pm_buf);
+	CU_ASSERT(len == g_volatile_pm_buf_len);
+	free(g_volatile_pm_buf);
+	g_volatile_pm_buf = NULL;
+	g_volatile_pm_buf_len = 0;
+
+	return 0;
+}
+
+static void
+persistent_pm_buf_destroy(void)
+{
+	CU_ASSERT(g_persistent_pm_buf != NULL);
+	free(g_persistent_pm_buf);
+	g_persistent_pm_buf = NULL;
+	g_persistent_pm_buf_len = 0;
+}
+
+static void
+unlink_cb(void)
+{
+	persistent_pm_buf_destroy();
+}
+
+static void
+init_cb(void *cb_arg, struct spdk_reduce_vol *vol, int reduce_errno)
+{
+	g_vol = vol;
+	g_reduce_errno = reduce_errno;
+}
+
+static void
+load_cb(void *cb_arg, struct spdk_reduce_vol *vol, int reduce_errno)
+{
+	g_vol = vol;
+	g_reduce_errno = reduce_errno;
+}
+
+static void
+unload_cb(void *cb_arg, int reduce_errno)
+{
+	g_reduce_errno = reduce_errno;
+}
+
+static void
+init_failure(void)
+{
+	struct spdk_reduce_vol_params params = {};
+	struct spdk_reduce_backing_dev backing_dev = {};
+
+	backing_dev.blocklen = 512;
+	/* This blockcnt is too small for a reduce vol - there needs to be
+	 *  enough space for at least REDUCE_NUM_EXTRA_CHUNKS + 1 chunks.
+	 */
+	backing_dev.blockcnt = 20;
+
+	params.vol_size = 0;
+	params.chunk_size = 16 * 1024;
+	params.backing_io_unit_size = backing_dev.blocklen;
+	params.logical_block_size = 512;
+
+	/* backing_dev has an invalid size.  This should fail. */
+	g_vol = NULL;
+	g_reduce_errno = 0;
+	spdk_reduce_vol_init(&params, &backing_dev, TEST_MD_PATH, init_cb, NULL);
+	CU_ASSERT(g_reduce_errno == -EINVAL);
+	SPDK_CU_ASSERT_FATAL(g_vol == NULL);
+
+	/* backing_dev now has valid size, but backing_dev still has null
+	 *  function pointers.  This should fail.
+	 */
+	backing_dev.blockcnt = 20000;
+
+	g_vol = NULL;
+	g_reduce_errno = 0;
+	spdk_reduce_vol_init(&params, &backing_dev, TEST_MD_PATH, init_cb, NULL);
+	CU_ASSERT(g_reduce_errno == -EINVAL);
+	SPDK_CU_ASSERT_FATAL(g_vol == NULL);
+}
+
+static void
+backing_dev_readv_execute(struct spdk_reduce_backing_dev *backing_dev,
+			  struct iovec *iov, int iovcnt,
+			  uint64_t lba, uint32_t lba_count,
+			  struct spdk_reduce_vol_cb_args *args)
+{
+	char *offset;
+	int i;
+
+	offset = g_backing_dev_buf + lba * backing_dev->blocklen;
+	for (i = 0; i < iovcnt; i++) {
+		memcpy(iov[i].iov_base, offset, iov[i].iov_len);
+		offset += iov[i].iov_len;
+	}
+	args->cb_fn(args->cb_arg, 0);
+}
+
+static void
+backing_dev_insert_io(enum ut_reduce_bdev_io_type type, struct spdk_reduce_backing_dev *backing_dev,
+		      struct iovec *iov, int iovcnt, uint64_t lba, uint32_t lba_count,
+		      struct spdk_reduce_vol_cb_args *args)
+{
+	struct ut_reduce_bdev_io *ut_bdev_io;
+
+	ut_bdev_io = calloc(1, sizeof(*ut_bdev_io));
+	SPDK_CU_ASSERT_FATAL(ut_bdev_io != NULL);
+
+	ut_bdev_io->type = type;
+	ut_bdev_io->backing_dev = backing_dev;
+	ut_bdev_io->iov = iov;
+	ut_bdev_io->iovcnt = iovcnt;
+	ut_bdev_io->lba = lba;
+	ut_bdev_io->lba_count = lba_count;
+	ut_bdev_io->args = args;
+	TAILQ_INSERT_TAIL(&g_pending_bdev_io, ut_bdev_io, link);
+	g_pending_bdev_io_count++;
+}
+
+static void
+backing_dev_readv(struct spdk_reduce_backing_dev *backing_dev, struct iovec *iov, int iovcnt,
+		  uint64_t lba, uint32_t lba_count, struct spdk_reduce_vol_cb_args *args)
+{
+	if (g_defer_bdev_io == false) {
+		CU_ASSERT(g_pending_bdev_io_count == 0);
+		CU_ASSERT(TAILQ_EMPTY(&g_pending_bdev_io));
+		backing_dev_readv_execute(backing_dev, iov, iovcnt, lba, lba_count, args);
+		return;
+	}
+
+	backing_dev_insert_io(UT_REDUCE_IO_READV, backing_dev, iov, iovcnt, lba, lba_count, args);
+}
+
+static void
+backing_dev_writev_execute(struct spdk_reduce_backing_dev *backing_dev,
+			   struct iovec *iov, int iovcnt,
+			   uint64_t lba, uint32_t lba_count,
+			   struct spdk_reduce_vol_cb_args *args)
+{
+	char *offset;
+	int i;
+
+	offset = g_backing_dev_buf + lba * backing_dev->blocklen;
+	for (i = 0; i < iovcnt; i++) {
+		memcpy(offset, iov[i].iov_base, iov[i].iov_len);
+		offset += iov[i].iov_len;
+	}
+	args->cb_fn(args->cb_arg, 0);
+}
+
+static void
+backing_dev_writev(struct spdk_reduce_backing_dev *backing_dev, struct iovec *iov, int iovcnt,
+		   uint64_t lba, uint32_t lba_count, struct spdk_reduce_vol_cb_args *args)
+{
+	if (g_defer_bdev_io == false) {
+		CU_ASSERT(g_pending_bdev_io_count == 0);
+		CU_ASSERT(TAILQ_EMPTY(&g_pending_bdev_io));
+		backing_dev_writev_execute(backing_dev, iov, iovcnt, lba, lba_count, args);
+		return;
+	}
+
+	backing_dev_insert_io(UT_REDUCE_IO_WRITEV, backing_dev, iov, iovcnt, lba, lba_count, args);
+}
+
+static void
+backing_dev_unmap_execute(struct spdk_reduce_backing_dev *backing_dev,
+			  uint64_t lba, uint32_t lba_count,
+			  struct spdk_reduce_vol_cb_args *args)
+{
+	char *offset;
+
+	offset = g_backing_dev_buf + lba * backing_dev->blocklen;
+	memset(offset, 0, lba_count * backing_dev->blocklen);
+	args->cb_fn(args->cb_arg, 0);
+}
+
+static void
+backing_dev_unmap(struct spdk_reduce_backing_dev *backing_dev,
+		  uint64_t lba, uint32_t lba_count, struct spdk_reduce_vol_cb_args *args)
+{
+	if (g_defer_bdev_io == false) {
+		CU_ASSERT(g_pending_bdev_io_count == 0);
+		CU_ASSERT(TAILQ_EMPTY(&g_pending_bdev_io));
+		backing_dev_unmap_execute(backing_dev, lba, lba_count, args);
+		return;
+	}
+
+	backing_dev_insert_io(UT_REDUCE_IO_UNMAP, backing_dev, NULL, 0, lba, lba_count, args);
+}
+
+static void
+backing_dev_io_execute(uint32_t count)
+{
+	struct ut_reduce_bdev_io *ut_bdev_io;
+	uint32_t done = 0;
+
+	CU_ASSERT(g_defer_bdev_io == true);
+	while (!TAILQ_EMPTY(&g_pending_bdev_io) && (count == 0 || done < count)) {
+		ut_bdev_io = TAILQ_FIRST(&g_pending_bdev_io);
+		TAILQ_REMOVE(&g_pending_bdev_io, ut_bdev_io, link);
+		g_pending_bdev_io_count--;
+		switch (ut_bdev_io->type) {
+		case UT_REDUCE_IO_READV:
+			backing_dev_readv_execute(ut_bdev_io->backing_dev,
+						  ut_bdev_io->iov, ut_bdev_io->iovcnt,
+						  ut_bdev_io->lba, ut_bdev_io->lba_count,
+						  ut_bdev_io->args);
+			break;
+		case UT_REDUCE_IO_WRITEV:
+			backing_dev_writev_execute(ut_bdev_io->backing_dev,
+						   ut_bdev_io->iov, ut_bdev_io->iovcnt,
+						   ut_bdev_io->lba, ut_bdev_io->lba_count,
+						   ut_bdev_io->args);
+			break;
+		case UT_REDUCE_IO_UNMAP:
+			backing_dev_unmap_execute(ut_bdev_io->backing_dev,
+						  ut_bdev_io->lba, ut_bdev_io->lba_count,
+						  ut_bdev_io->args);
+			break;
+		default:
+			CU_ASSERT(false);
+			break;
+		}
+		free(ut_bdev_io);
+		done++;
+	}
+}
+
+static int
+ut_compress(char *outbuf, uint32_t *compressed_len, char *inbuf, uint32_t inbuflen)
+{
+	uint32_t len = 0;
+	uint8_t count;
+	char last;
+
+	while (true) {
+		if (inbuflen == 0) {
+			*compressed_len = len;
+			return 0;
+		}
+
+		if (*compressed_len < (len + 2)) {
+			return -ENOSPC;
+		}
+
+		last = *inbuf;
+		count = 1;
+		inbuflen--;
+		inbuf++;
+
+		while (inbuflen > 0 && *inbuf == last && count < UINT8_MAX) {
+			count++;
+			inbuflen--;
+			inbuf++;
+		}
+
+		outbuf[len] = count;
+		outbuf[len + 1] = last;
+		len += 2;
+	}
+}
+
+static int
+ut_decompress(uint8_t *outbuf, uint32_t *compressed_len, uint8_t *inbuf, uint32_t inbuflen)
+{
+	uint32_t len = 0;
+
+	SPDK_CU_ASSERT_FATAL(inbuflen % 2 == 0);
+
+	while (true) {
+		if (inbuflen == 0) {
+			*compressed_len = len;
+			return 0;
+		}
+
+		if ((len + inbuf[0]) > *compressed_len) {
+			return -ENOSPC;
+		}
+
+		memset(outbuf, inbuf[1], inbuf[0]);
+		outbuf += inbuf[0];
+		len += inbuf[0];
+		inbuflen -= 2;
+		inbuf += 2;
+	}
+}
+
+static void
+ut_build_data_buffer(uint8_t *data, uint32_t data_len, uint8_t init_val, uint32_t repeat)
+{
+	uint32_t _repeat = repeat;
+
+	SPDK_CU_ASSERT_FATAL(repeat > 0);
+
+	while (data_len > 0) {
+		*data = init_val;
+		data++;
+		data_len--;
+		_repeat--;
+		if (_repeat == 0) {
+			init_val++;
+			_repeat = repeat;
+		}
+	}
+}
+
+static void
+backing_dev_compress(struct spdk_reduce_backing_dev *backing_dev,
+		     struct iovec *src_iov, int src_iovcnt,
+		     struct iovec *dst_iov, int dst_iovcnt,
+		     struct spdk_reduce_vol_cb_args *args)
+{
+	uint32_t compressed_len;
+	uint64_t total_length = 0;
+	char *buf = g_decomp_buf;
+	int rc, i;
+
+	CU_ASSERT(dst_iovcnt == 1);
+
+	for (i = 0; i < src_iovcnt; i++) {
+		memcpy(buf, src_iov[i].iov_base, src_iov[i].iov_len);
+		buf += src_iov[i].iov_len;
+		total_length += src_iov[i].iov_len;
+	}
+
+	compressed_len = dst_iov[0].iov_len;
+	rc = ut_compress(dst_iov[0].iov_base, &compressed_len,
+			 g_decomp_buf, total_length);
+
+	args->cb_fn(args->cb_arg, rc ? rc : (int)compressed_len);
+}
+
+static void
+backing_dev_decompress(struct spdk_reduce_backing_dev *backing_dev,
+		       struct iovec *src_iov, int src_iovcnt,
+		       struct iovec *dst_iov, int dst_iovcnt,
+		       struct spdk_reduce_vol_cb_args *args)
+{
+	uint32_t decompressed_len = 0;
+	char *buf = g_decomp_buf;
+	int rc, i;
+
+	CU_ASSERT(src_iovcnt == 1);
+
+	for (i = 0; i < dst_iovcnt; i++) {
+		decompressed_len += dst_iov[i].iov_len;
+	}
+
+	rc = ut_decompress(g_decomp_buf, &decompressed_len,
+			   src_iov[0].iov_base, src_iov[0].iov_len);
+
+	for (i = 0; i < dst_iovcnt; i++) {
+		memcpy(dst_iov[i].iov_base, buf, dst_iov[i].iov_len);
+		buf += dst_iov[i].iov_len;
+	}
+
+	args->cb_fn(args->cb_arg, rc ? rc : (int)decompressed_len);
+}
+
+static void
+backing_dev_destroy(struct spdk_reduce_backing_dev *backing_dev)
+{
+	/* We don't free this during backing_dev_close so that we can test init/unload/load
+	 *  scenarios.
+	 */
+	free(g_backing_dev_buf);
+	free(g_decomp_buf);
+	g_backing_dev_buf = NULL;
+}
+
+static void
+backing_dev_init(struct spdk_reduce_backing_dev *backing_dev, struct spdk_reduce_vol_params *params,
+		 uint32_t backing_blocklen)
+{
+	int64_t size;
+
+	size = 4 * 1024 * 1024;
+	backing_dev->blocklen = backing_blocklen;
+	backing_dev->blockcnt = size / backing_dev->blocklen;
+	backing_dev->readv = backing_dev_readv;
+	backing_dev->writev = backing_dev_writev;
+	backing_dev->unmap = backing_dev_unmap;
+	backing_dev->compress = backing_dev_compress;
+	backing_dev->decompress = backing_dev_decompress;
+
+	g_decomp_buf = calloc(1, params->chunk_size);
+	SPDK_CU_ASSERT_FATAL(g_decomp_buf != NULL);
+
+	g_backing_dev_buf = calloc(1, size);
+	SPDK_CU_ASSERT_FATAL(g_backing_dev_buf != NULL);
+}
+
+static void
+init_md(void)
+{
+	struct spdk_reduce_vol_params params = {};
+	struct spdk_reduce_vol_params *persistent_params;
+	struct spdk_reduce_backing_dev backing_dev = {};
+	struct spdk_uuid uuid;
+	uint64_t *entry;
+
+	params.chunk_size = 16 * 1024;
+	params.backing_io_unit_size = 512;
+	params.logical_block_size = 512;
+
+	backing_dev_init(&backing_dev, &params, 512);
+
+	g_vol = NULL;
+	g_reduce_errno = -1;
+	spdk_reduce_vol_init(&params, &backing_dev, TEST_MD_PATH, init_cb, NULL);
+	CU_ASSERT(g_reduce_errno == 0);
+	SPDK_CU_ASSERT_FATAL(g_vol != NULL);
+	/* Confirm that reduce persisted the params to metadata. */
+	CU_ASSERT(memcmp(g_persistent_pm_buf, SPDK_REDUCE_SIGNATURE, 8) == 0);
+	persistent_params = (struct spdk_reduce_vol_params *)(g_persistent_pm_buf + 8);
+	CU_ASSERT(memcmp(persistent_params, &params, sizeof(params)) == 0);
+	/* Now confirm that contents of pm_file after the superblock have been initialized
+	 *  to REDUCE_EMPTY_MAP_ENTRY.
+	 */
+	entry = (uint64_t *)(g_persistent_pm_buf + sizeof(struct spdk_reduce_vol_superblock));
+	while (entry != (uint64_t *)(g_persistent_pm_buf + g_vol->pm_file.size)) {
+		CU_ASSERT(*entry == REDUCE_EMPTY_MAP_ENTRY);
+		entry++;
+	}
+
+	/* Check that the pm file path was constructed correctly.  It should be in
+	 * the form:
+	 * TEST_MD_PATH + "/" + <uuid string>
+	 */
+	CU_ASSERT(strncmp(&g_path[0], TEST_MD_PATH, strlen(TEST_MD_PATH)) == 0);
+	CU_ASSERT(g_path[strlen(TEST_MD_PATH)] == '/');
+	CU_ASSERT(spdk_uuid_parse(&uuid, &g_path[strlen(TEST_MD_PATH) + 1]) == 0);
+	CU_ASSERT(spdk_uuid_compare(&uuid, spdk_reduce_vol_get_uuid(g_vol)) == 0);
+
+	g_reduce_errno = -1;
+	spdk_reduce_vol_unload(g_vol, unload_cb, NULL);
+	CU_ASSERT(g_reduce_errno == 0);
+	CU_ASSERT(g_volatile_pm_buf == NULL);
+
+	persistent_pm_buf_destroy();
+	backing_dev_destroy(&backing_dev);
+}
+
+static void
+_init_backing_dev(uint32_t backing_blocklen)
+{
+	struct spdk_reduce_vol_params params = {};
+	struct spdk_reduce_vol_params *persistent_params;
+	struct spdk_reduce_backing_dev backing_dev = {};
+
+	params.chunk_size = 16 * 1024;
+	params.backing_io_unit_size = 512;
+	params.logical_block_size = 512;
+	spdk_uuid_generate(&params.uuid);
+
+	backing_dev_init(&backing_dev, &params, backing_blocklen);
+
+	g_vol = NULL;
+	memset(g_path, 0, sizeof(g_path));
+	g_reduce_errno = -1;
+	spdk_reduce_vol_init(&params, &backing_dev, TEST_MD_PATH, init_cb, NULL);
+	CU_ASSERT(g_reduce_errno == 0);
+	SPDK_CU_ASSERT_FATAL(g_vol != NULL);
+	CU_ASSERT(strncmp(TEST_MD_PATH, g_path, strlen(TEST_MD_PATH)) == 0);
+	/* Confirm that libreduce persisted the params to the backing device. */
+	CU_ASSERT(memcmp(g_backing_dev_buf, SPDK_REDUCE_SIGNATURE, 8) == 0);
+	persistent_params = (struct spdk_reduce_vol_params *)(g_backing_dev_buf + 8);
+	CU_ASSERT(memcmp(persistent_params, &params, sizeof(params)) == 0);
+	/* Confirm that the path to the persistent memory metadata file was persisted to
+	 *  the backing device.
+	 */
+	CU_ASSERT(strncmp(g_path,
+			  g_backing_dev_buf + REDUCE_BACKING_DEV_PATH_OFFSET,
+			  REDUCE_PATH_MAX) == 0);
+
+	g_reduce_errno = -1;
+	spdk_reduce_vol_unload(g_vol, unload_cb, NULL);
+	CU_ASSERT(g_reduce_errno == 0);
+
+	persistent_pm_buf_destroy();
+	backing_dev_destroy(&backing_dev);
+}
+
+static void
+init_backing_dev(void)
+{
+	_init_backing_dev(512);
+	_init_backing_dev(4096);
+}
+
+static void
+_load(uint32_t backing_blocklen)
+{
+	struct spdk_reduce_vol_params params = {};
+	struct spdk_reduce_backing_dev backing_dev = {};
+	char pmem_file_path[REDUCE_PATH_MAX];
+
+	params.chunk_size = 16 * 1024;
+	params.backing_io_unit_size = 512;
+	params.logical_block_size = 512;
+	spdk_uuid_generate(&params.uuid);
+
+	backing_dev_init(&backing_dev, &params, backing_blocklen);
+
+	g_vol = NULL;
+	g_reduce_errno = -1;
+	spdk_reduce_vol_init(&params, &backing_dev, TEST_MD_PATH, init_cb, NULL);
+	CU_ASSERT(g_reduce_errno == 0);
+	SPDK_CU_ASSERT_FATAL(g_vol != NULL);
+	CU_ASSERT(strncmp(TEST_MD_PATH, g_path, strlen(TEST_MD_PATH)) == 0);
+	memcpy(pmem_file_path, g_path, sizeof(pmem_file_path));
+
+	g_reduce_errno = -1;
+	spdk_reduce_vol_unload(g_vol, unload_cb, NULL);
+	CU_ASSERT(g_reduce_errno == 0);
+
+	g_vol = NULL;
+	memset(g_path, 0, sizeof(g_path));
+	g_reduce_errno = -1;
+	spdk_reduce_vol_load(&backing_dev, load_cb, NULL);
+	CU_ASSERT(g_reduce_errno == 0);
+	SPDK_CU_ASSERT_FATAL(g_vol != NULL);
+	CU_ASSERT(strncmp(g_path, pmem_file_path, sizeof(pmem_file_path)) == 0);
+	CU_ASSERT(g_vol->params.vol_size == params.vol_size);
+	CU_ASSERT(g_vol->params.chunk_size == params.chunk_size);
+	CU_ASSERT(g_vol->params.backing_io_unit_size == params.backing_io_unit_size);
+
+	g_reduce_errno = -1;
+	spdk_reduce_vol_unload(g_vol, unload_cb, NULL);
+	CU_ASSERT(g_reduce_errno == 0);
+
+	persistent_pm_buf_destroy();
+	backing_dev_destroy(&backing_dev);
+}
+
+static void
+load(void)
+{
+	_load(512);
+	_load(4096);
+}
+
+static uint64_t
+_vol_get_chunk_map_index(struct spdk_reduce_vol *vol, uint64_t offset)
+{
+	uint64_t logical_map_index = offset / vol->logical_blocks_per_chunk;
+
+	return vol->pm_logical_map[logical_map_index];
+}
+
+static void
+write_cb(void *arg, int reduce_errno)
+{
+	g_reduce_errno = reduce_errno;
+}
+
+static void
+read_cb(void *arg, int reduce_errno)
+{
+	g_reduce_errno = reduce_errno;
+}
+
+static void
+_write_maps(uint32_t backing_blocklen)
+{
+	struct spdk_reduce_vol_params params = {};
+	struct spdk_reduce_backing_dev backing_dev = {};
+	struct iovec iov;
+	const int bufsize = 16 * 1024; /* chunk size */
+	char buf[bufsize];
+	uint32_t num_lbas, i;
+	uint64_t old_chunk0_map_index, new_chunk0_map_index;
+	struct spdk_reduce_chunk_map *old_chunk0_map, *new_chunk0_map;
+
+	params.chunk_size = bufsize;
+	params.backing_io_unit_size = 4096;
+	params.logical_block_size = 512;
+	num_lbas = bufsize / params.logical_block_size;
+	spdk_uuid_generate(&params.uuid);
+
+	backing_dev_init(&backing_dev, &params, backing_blocklen);
+
+	g_vol = NULL;
+	g_reduce_errno = -1;
+	spdk_reduce_vol_init(&params, &backing_dev, TEST_MD_PATH, init_cb, NULL);
+	CU_ASSERT(g_reduce_errno == 0);
+	SPDK_CU_ASSERT_FATAL(g_vol != NULL);
+
+	for (i = 0; i < g_vol->params.vol_size / g_vol->params.chunk_size; i++) {
+		CU_ASSERT(_vol_get_chunk_map_index(g_vol, i) == REDUCE_EMPTY_MAP_ENTRY);
+	}
+
+	ut_build_data_buffer(buf, bufsize, 0x00, 1);
+	iov.iov_base = buf;
+	iov.iov_len = bufsize;
+	g_reduce_errno = -1;
+	spdk_reduce_vol_writev(g_vol, &iov, 1, 0, num_lbas, write_cb, NULL);
+	CU_ASSERT(g_reduce_errno == 0);
+
+	old_chunk0_map_index = _vol_get_chunk_map_index(g_vol, 0);
+	CU_ASSERT(old_chunk0_map_index != REDUCE_EMPTY_MAP_ENTRY);
+	CU_ASSERT(spdk_bit_array_get(g_vol->allocated_chunk_maps, old_chunk0_map_index) == true);
+
+	old_chunk0_map = _reduce_vol_get_chunk_map(g_vol, old_chunk0_map_index);
+	for (i = 0; i < g_vol->backing_io_units_per_chunk; i++) {
+		CU_ASSERT(old_chunk0_map->io_unit_index[i] != REDUCE_EMPTY_MAP_ENTRY);
+		CU_ASSERT(spdk_bit_array_get(g_vol->allocated_backing_io_units,
+					     old_chunk0_map->io_unit_index[i]) == true);
+	}
+
+	g_reduce_errno = -1;
+	spdk_reduce_vol_writev(g_vol, &iov, 1, 0, num_lbas, write_cb, NULL);
+	CU_ASSERT(g_reduce_errno == 0);
+
+	new_chunk0_map_index = _vol_get_chunk_map_index(g_vol, 0);
+	CU_ASSERT(new_chunk0_map_index != REDUCE_EMPTY_MAP_ENTRY);
+	CU_ASSERT(new_chunk0_map_index != old_chunk0_map_index);
+	CU_ASSERT(spdk_bit_array_get(g_vol->allocated_chunk_maps, new_chunk0_map_index) == true);
+	CU_ASSERT(spdk_bit_array_get(g_vol->allocated_chunk_maps, old_chunk0_map_index) == false);
+
+	for (i = 0; i < g_vol->backing_io_units_per_chunk; i++) {
+		CU_ASSERT(spdk_bit_array_get(g_vol->allocated_backing_io_units,
+					     old_chunk0_map->io_unit_index[i]) == false);
+	}
+
+	new_chunk0_map = _reduce_vol_get_chunk_map(g_vol, new_chunk0_map_index);
+	for (i = 0; i < g_vol->backing_io_units_per_chunk; i++) {
+		CU_ASSERT(new_chunk0_map->io_unit_index[i] != REDUCE_EMPTY_MAP_ENTRY);
+		CU_ASSERT(spdk_bit_array_get(g_vol->allocated_backing_io_units,
+					     new_chunk0_map->io_unit_index[i]) == true);
+	}
+
+	g_reduce_errno = -1;
+	spdk_reduce_vol_unload(g_vol, unload_cb, NULL);
+	CU_ASSERT(g_reduce_errno == 0);
+
+	g_vol = NULL;
+	g_reduce_errno = -1;
+	spdk_reduce_vol_load(&backing_dev, load_cb, NULL);
+	CU_ASSERT(g_reduce_errno == 0);
+	SPDK_CU_ASSERT_FATAL(g_vol != NULL);
+	CU_ASSERT(g_vol->params.vol_size == params.vol_size);
+	CU_ASSERT(g_vol->params.chunk_size == params.chunk_size);
+	CU_ASSERT(g_vol->params.backing_io_unit_size == params.backing_io_unit_size);
+
+	g_reduce_errno = -1;
+	spdk_reduce_vol_unload(g_vol, unload_cb, NULL);
+	CU_ASSERT(g_reduce_errno == 0);
+
+	persistent_pm_buf_destroy();
+	backing_dev_destroy(&backing_dev);
+}
+
+static void
+write_maps(void)
+{
+	_write_maps(512);
+	_write_maps(4096);
+}
+
+static void
+_read_write(uint32_t backing_blocklen)
+{
+	struct spdk_reduce_vol_params params = {};
+	struct spdk_reduce_backing_dev backing_dev = {};
+	struct iovec iov;
+	char buf[16 * 1024]; /* chunk size */
+	char compare_buf[16 * 1024];
+	uint32_t i;
+
+	params.chunk_size = 16 * 1024;
+	params.backing_io_unit_size = 4096;
+	params.logical_block_size = 512;
+	spdk_uuid_generate(&params.uuid);
+
+	backing_dev_init(&backing_dev, &params, backing_blocklen);
+
+	g_vol = NULL;
+	g_reduce_errno = -1;
+	spdk_reduce_vol_init(&params, &backing_dev, TEST_MD_PATH, init_cb, NULL);
+	CU_ASSERT(g_reduce_errno == 0);
+	SPDK_CU_ASSERT_FATAL(g_vol != NULL);
+
+	/* Write 0xAA to 2 512-byte logical blocks, starting at LBA 2. */
+	memset(buf, 0xAA, 2 * params.logical_block_size);
+	iov.iov_base = buf;
+	iov.iov_len = 2 * params.logical_block_size;
+	g_reduce_errno = -1;
+	spdk_reduce_vol_writev(g_vol, &iov, 1, 2, 2, write_cb, NULL);
+	CU_ASSERT(g_reduce_errno == 0);
+
+	memset(compare_buf, 0xAA, sizeof(compare_buf));
+	for (i = 0; i < params.chunk_size / params.logical_block_size; i++) {
+		memset(buf, 0xFF, params.logical_block_size);
+		iov.iov_base = buf;
+		iov.iov_len = params.logical_block_size;
+		g_reduce_errno = -1;
+		spdk_reduce_vol_readv(g_vol, &iov, 1, i, 1, read_cb, NULL);
+		CU_ASSERT(g_reduce_errno == 0);
+
+		switch (i) {
+		case 2:
+		case 3:
+			CU_ASSERT(memcmp(buf, compare_buf, params.logical_block_size) == 0);
+			break;
+		default:
+			CU_ASSERT(spdk_mem_all_zero(buf, params.logical_block_size));
+			break;
+		}
+	}
+
+	g_reduce_errno = -1;
+	spdk_reduce_vol_unload(g_vol, unload_cb, NULL);
+	CU_ASSERT(g_reduce_errno == 0);
+
+	/* Overwrite what we just wrote with 0xCC */
+	g_vol = NULL;
+	g_reduce_errno = -1;
+	spdk_reduce_vol_load(&backing_dev, load_cb, NULL);
+	CU_ASSERT(g_reduce_errno == 0);
+	SPDK_CU_ASSERT_FATAL(g_vol != NULL);
+	CU_ASSERT(g_vol->params.vol_size == params.vol_size);
+	CU_ASSERT(g_vol->params.chunk_size == params.chunk_size);
+	CU_ASSERT(g_vol->params.backing_io_unit_size == params.backing_io_unit_size);
+
+	memset(buf, 0xCC, 2 * params.logical_block_size);
+	iov.iov_base = buf;
+	iov.iov_len = 2 * params.logical_block_size;
+	g_reduce_errno = -1;
+	spdk_reduce_vol_writev(g_vol, &iov, 1, 2, 2, write_cb, NULL);
+	CU_ASSERT(g_reduce_errno == 0);
+
+	memset(compare_buf, 0xCC, sizeof(compare_buf));
+	for (i = 0; i < params.chunk_size / params.logical_block_size; i++) {
+		memset(buf, 0xFF, params.logical_block_size);
+		iov.iov_base = buf;
+		iov.iov_len = params.logical_block_size;
+		g_reduce_errno = -1;
+		spdk_reduce_vol_readv(g_vol, &iov, 1, i, 1, read_cb, NULL);
+		CU_ASSERT(g_reduce_errno == 0);
+
+		switch (i) {
+		case 2:
+		case 3:
+			CU_ASSERT(memcmp(buf, compare_buf, params.logical_block_size) == 0);
+			break;
+		default:
+			CU_ASSERT(spdk_mem_all_zero(buf, params.logical_block_size));
+			break;
+		}
+	}
+
+	g_reduce_errno = -1;
+	spdk_reduce_vol_unload(g_vol, unload_cb, NULL);
+	CU_ASSERT(g_reduce_errno == 0);
+
+	g_vol = NULL;
+	g_reduce_errno = -1;
+	spdk_reduce_vol_load(&backing_dev, load_cb, NULL);
+	CU_ASSERT(g_reduce_errno == 0);
+	SPDK_CU_ASSERT_FATAL(g_vol != NULL);
+	CU_ASSERT(g_vol->params.vol_size == params.vol_size);
+	CU_ASSERT(g_vol->params.chunk_size == params.chunk_size);
+	CU_ASSERT(g_vol->params.backing_io_unit_size == params.backing_io_unit_size);
+
+	g_reduce_errno = -1;
+
+	/* Write 0xBB to 2 512-byte logical blocks, starting at LBA 37.
+	 * This is writing into the second chunk of the volume.  This also
+	 * enables implicitly checking that we reloaded the bit arrays
+	 * correctly - making sure we don't use the first chunk map again
+	 * for this new write - the first chunk map was already used by the
+	 * write from before we unloaded and reloaded.
+	 */
+	memset(buf, 0xBB, 2 * params.logical_block_size);
+	iov.iov_base = buf;
+	iov.iov_len = 2 * params.logical_block_size;
+	g_reduce_errno = -1;
+	spdk_reduce_vol_writev(g_vol, &iov, 1, 37, 2, write_cb, NULL);
+	CU_ASSERT(g_reduce_errno == 0);
+
+	for (i = 0; i < 2 * params.chunk_size / params.logical_block_size; i++) {
+		memset(buf, 0xFF, params.logical_block_size);
+		iov.iov_base = buf;
+		iov.iov_len = params.logical_block_size;
+		g_reduce_errno = -1;
+		spdk_reduce_vol_readv(g_vol, &iov, 1, i, 1, read_cb, NULL);
+		CU_ASSERT(g_reduce_errno == 0);
+
+		switch (i) {
+		case 2:
+		case 3:
+			memset(compare_buf, 0xCC, sizeof(compare_buf));
+			CU_ASSERT(memcmp(buf, compare_buf, params.logical_block_size) == 0);
+			break;
+		case 37:
+		case 38:
+			memset(compare_buf, 0xBB, sizeof(compare_buf));
+			CU_ASSERT(memcmp(buf, compare_buf, params.logical_block_size) == 0);
+			break;
+		default:
+			CU_ASSERT(spdk_mem_all_zero(buf, params.logical_block_size));
+			break;
+		}
+	}
+
+	g_reduce_errno = -1;
+	spdk_reduce_vol_unload(g_vol, unload_cb, NULL);
+	CU_ASSERT(g_reduce_errno == 0);
+
+	persistent_pm_buf_destroy();
+	backing_dev_destroy(&backing_dev);
+}
+
+static void
+read_write(void)
+{
+	_read_write(512);
+	_read_write(4096);
+}
+
+static void
+_readv_writev(uint32_t backing_blocklen)
+{
+	struct spdk_reduce_vol_params params = {};
+	struct spdk_reduce_backing_dev backing_dev = {};
+	struct iovec iov[REDUCE_MAX_IOVECS + 1];
+
+	params.chunk_size = 16 * 1024;
+	params.backing_io_unit_size = 4096;
+	params.logical_block_size = 512;
+	spdk_uuid_generate(&params.uuid);
+
+	backing_dev_init(&backing_dev, &params, backing_blocklen);
+
+	g_vol = NULL;
+	g_reduce_errno = -1;
+	spdk_reduce_vol_init(&params, &backing_dev, TEST_MD_PATH, init_cb, NULL);
+	CU_ASSERT(g_reduce_errno == 0);
+	SPDK_CU_ASSERT_FATAL(g_vol != NULL);
+
+	g_reduce_errno = -1;
+	spdk_reduce_vol_writev(g_vol, iov, REDUCE_MAX_IOVECS + 1, 2, REDUCE_MAX_IOVECS + 1, write_cb, NULL);
+	CU_ASSERT(g_reduce_errno == -EINVAL);
+
+	g_reduce_errno = -1;
+	spdk_reduce_vol_unload(g_vol, unload_cb, NULL);
+	CU_ASSERT(g_reduce_errno == 0);
+
+	persistent_pm_buf_destroy();
+	backing_dev_destroy(&backing_dev);
+}
+
+static void
+readv_writev(void)
+{
+	_readv_writev(512);
+	_readv_writev(4096);
+}
+
+static void
+destroy_cb(void *ctx, int reduce_errno)
+{
+	g_reduce_errno = reduce_errno;
+}
+
+static void
+destroy(void)
+{
+	struct spdk_reduce_vol_params params = {};
+	struct spdk_reduce_backing_dev backing_dev = {};
+
+	params.chunk_size = 16 * 1024;
+	params.backing_io_unit_size = 512;
+	params.logical_block_size = 512;
+	spdk_uuid_generate(&params.uuid);
+
+	backing_dev_init(&backing_dev, &params, 512);
+
+	g_vol = NULL;
+	g_reduce_errno = -1;
+	spdk_reduce_vol_init(&params, &backing_dev, TEST_MD_PATH, init_cb, NULL);
+	CU_ASSERT(g_reduce_errno == 0);
+	SPDK_CU_ASSERT_FATAL(g_vol != NULL);
+
+	g_reduce_errno = -1;
+	spdk_reduce_vol_unload(g_vol, unload_cb, NULL);
+	CU_ASSERT(g_reduce_errno == 0);
+
+	g_vol = NULL;
+	g_reduce_errno = -1;
+	spdk_reduce_vol_load(&backing_dev, load_cb, NULL);
+	CU_ASSERT(g_reduce_errno == 0);
+	SPDK_CU_ASSERT_FATAL(g_vol != NULL);
+
+	g_reduce_errno = -1;
+	spdk_reduce_vol_unload(g_vol, unload_cb, NULL);
+	CU_ASSERT(g_reduce_errno == 0);
+
+	g_reduce_errno = -1;
+	MOCK_CLEAR(spdk_malloc);
+	MOCK_CLEAR(spdk_zmalloc);
+	spdk_reduce_vol_destroy(&backing_dev, destroy_cb, NULL);
+	CU_ASSERT(g_reduce_errno == 0);
+
+	g_reduce_errno = 0;
+	spdk_reduce_vol_load(&backing_dev, load_cb, NULL);
+	CU_ASSERT(g_reduce_errno == -EILSEQ);
+
+	backing_dev_destroy(&backing_dev);
+}
+
+/* This test primarily checks that the reduce unit test infrastructure for asynchronous
+ * backing device I/O operations is working correctly.
+ */
+static void
+defer_bdev_io(void)
+{
+	struct spdk_reduce_vol_params params = {};
+	struct spdk_reduce_backing_dev backing_dev = {};
+	const uint32_t logical_block_size = 512;
+	struct iovec iov;
+	char buf[logical_block_size];
+	char compare_buf[logical_block_size];
+
+	params.chunk_size = 16 * 1024;
+	params.backing_io_unit_size = 4096;
+	params.logical_block_size = logical_block_size;
+	spdk_uuid_generate(&params.uuid);
+
+	backing_dev_init(&backing_dev, &params, 512);
+
+	g_vol = NULL;
+	g_reduce_errno = -1;
+	spdk_reduce_vol_init(&params, &backing_dev, TEST_MD_PATH, init_cb, NULL);
+	CU_ASSERT(g_reduce_errno == 0);
+	SPDK_CU_ASSERT_FATAL(g_vol != NULL);
+
+	/* Write 0xAA to 1 512-byte logical block. */
+	memset(buf, 0xAA, params.logical_block_size);
+	iov.iov_base = buf;
+	iov.iov_len = params.logical_block_size;
+	g_reduce_errno = -100;
+	g_defer_bdev_io = true;
+	spdk_reduce_vol_writev(g_vol, &iov, 1, 0, 1, write_cb, NULL);
+	/* Callback should not have executed, so this should still equal -100. */
+	CU_ASSERT(g_reduce_errno == -100);
+	CU_ASSERT(!TAILQ_EMPTY(&g_pending_bdev_io));
+	/* We wrote to just 512 bytes of one chunk which was previously unallocated.  This
+	 * should result in 1 pending I/O since the rest of this chunk will be zeroes and
+	 * very compressible.
+	 */
+	CU_ASSERT(g_pending_bdev_io_count == 1);
+
+	backing_dev_io_execute(0);
+	CU_ASSERT(TAILQ_EMPTY(&g_pending_bdev_io));
+	CU_ASSERT(g_reduce_errno == 0);
+
+	g_defer_bdev_io = false;
+	memset(compare_buf, 0xAA, sizeof(compare_buf));
+	memset(buf, 0xFF, sizeof(buf));
+	iov.iov_base = buf;
+	iov.iov_len = params.logical_block_size;
+	g_reduce_errno = -100;
+	spdk_reduce_vol_readv(g_vol, &iov, 1, 0, 1, read_cb, NULL);
+	CU_ASSERT(g_reduce_errno == 0);
+	CU_ASSERT(memcmp(buf, compare_buf, sizeof(buf)) == 0);
+
+	g_reduce_errno = -1;
+	spdk_reduce_vol_unload(g_vol, unload_cb, NULL);
+	CU_ASSERT(g_reduce_errno == 0);
+
+	persistent_pm_buf_destroy();
+	backing_dev_destroy(&backing_dev);
+}
+
+static void
+overlapped(void)
+{
+	struct spdk_reduce_vol_params params = {};
+	struct spdk_reduce_backing_dev backing_dev = {};
+	const uint32_t logical_block_size = 512;
+	struct iovec iov;
+	char buf[2 * logical_block_size];
+	char compare_buf[2 * logical_block_size];
+
+	params.chunk_size = 16 * 1024;
+	params.backing_io_unit_size = 4096;
+	params.logical_block_size = logical_block_size;
+	spdk_uuid_generate(&params.uuid);
+
+	backing_dev_init(&backing_dev, &params, 512);
+
+	g_vol = NULL;
+	g_reduce_errno = -1;
+	spdk_reduce_vol_init(&params, &backing_dev, TEST_MD_PATH, init_cb, NULL);
+	CU_ASSERT(g_reduce_errno == 0);
+	SPDK_CU_ASSERT_FATAL(g_vol != NULL);
+
+	/* Write 0xAA to 1 512-byte logical block. */
+	memset(buf, 0xAA, logical_block_size);
+	iov.iov_base = buf;
+	iov.iov_len = logical_block_size;
+	g_reduce_errno = -100;
+	g_defer_bdev_io = true;
+	spdk_reduce_vol_writev(g_vol, &iov, 1, 0, 1, write_cb, NULL);
+	/* Callback should not have executed, so this should still equal -100. */
+	CU_ASSERT(g_reduce_errno == -100);
+	CU_ASSERT(!TAILQ_EMPTY(&g_pending_bdev_io));
+	/* We wrote to just 512 bytes of one chunk which was previously unallocated.  This
+	 * should result in 1 pending I/O since the rest of this chunk will be zeroes and
+	 * very compressible.
+	 */
+	CU_ASSERT(g_pending_bdev_io_count == 1);
+
+	/* Now do an overlapped I/O to the same chunk. */
+	spdk_reduce_vol_writev(g_vol, &iov, 1, 1, 1, write_cb, NULL);
+	/* Callback should not have executed, so this should still equal -100. */
+	CU_ASSERT(g_reduce_errno == -100);
+	CU_ASSERT(!TAILQ_EMPTY(&g_pending_bdev_io));
+	/* The second I/O overlaps with the first one.  So we should only see pending bdev_io
+	 * related to the first I/O here - the second one won't start until the first one is completed.
+	 */
+	CU_ASSERT(g_pending_bdev_io_count == 1);
+
+	backing_dev_io_execute(0);
+	CU_ASSERT(g_reduce_errno == 0);
+
+	g_defer_bdev_io = false;
+	memset(compare_buf, 0xAA, sizeof(compare_buf));
+	memset(buf, 0xFF, sizeof(buf));
+	iov.iov_base = buf;
+	iov.iov_len = 2 * logical_block_size;
+	g_reduce_errno = -100;
+	spdk_reduce_vol_readv(g_vol, &iov, 1, 0, 2, read_cb, NULL);
+	CU_ASSERT(g_reduce_errno == 0);
+	CU_ASSERT(memcmp(buf, compare_buf, 2 * logical_block_size) == 0);
+
+	g_reduce_errno = -1;
+	spdk_reduce_vol_unload(g_vol, unload_cb, NULL);
+	CU_ASSERT(g_reduce_errno == 0);
+
+	persistent_pm_buf_destroy();
+	backing_dev_destroy(&backing_dev);
+}
+
+#define BUFSIZE 4096
+
+static void
+compress_algorithm(void)
+{
+	uint8_t original_data[BUFSIZE];
+	uint8_t compressed_data[BUFSIZE];
+	uint8_t decompressed_data[BUFSIZE];
+	uint32_t compressed_len, decompressed_len;
+	int rc;
+
+	ut_build_data_buffer(original_data, BUFSIZE, 0xAA, BUFSIZE);
+	compressed_len = sizeof(compressed_data);
+	rc = ut_compress(compressed_data, &compressed_len, original_data, UINT8_MAX);
+	CU_ASSERT(rc == 0);
+	CU_ASSERT(compressed_len == 2);
+	CU_ASSERT(compressed_data[0] == UINT8_MAX);
+	CU_ASSERT(compressed_data[1] == 0xAA);
+
+	decompressed_len = sizeof(decompressed_data);
+	rc = ut_decompress(decompressed_data, &decompressed_len, compressed_data, compressed_len);
+	CU_ASSERT(rc == 0);
+	CU_ASSERT(decompressed_len == UINT8_MAX);
+	CU_ASSERT(memcmp(original_data, decompressed_data, decompressed_len) == 0);
+
+	compressed_len = sizeof(compressed_data);
+	rc = ut_compress(compressed_data, &compressed_len, original_data, UINT8_MAX + 1);
+	CU_ASSERT(rc == 0);
+	CU_ASSERT(compressed_len == 4);
+	CU_ASSERT(compressed_data[0] == UINT8_MAX);
+	CU_ASSERT(compressed_data[1] == 0xAA);
+	CU_ASSERT(compressed_data[2] == 1);
+	CU_ASSERT(compressed_data[3] == 0xAA);
+
+	decompressed_len = sizeof(decompressed_data);
+	rc = ut_decompress(decompressed_data, &decompressed_len, compressed_data, compressed_len);
+	CU_ASSERT(rc == 0);
+	CU_ASSERT(decompressed_len == UINT8_MAX + 1);
+	CU_ASSERT(memcmp(original_data, decompressed_data, decompressed_len) == 0);
+
+	ut_build_data_buffer(original_data, BUFSIZE, 0x00, 1);
+	compressed_len = sizeof(compressed_data);
+	rc = ut_compress(compressed_data, &compressed_len, original_data, 2048);
+	CU_ASSERT(rc == 0);
+	CU_ASSERT(compressed_len == 4096);
+	CU_ASSERT(compressed_data[0] == 1);
+	CU_ASSERT(compressed_data[1] == 0);
+	CU_ASSERT(compressed_data[4094] == 1);
+	CU_ASSERT(compressed_data[4095] == 0xFF);
+
+	decompressed_len = sizeof(decompressed_data);
+	rc = ut_decompress(decompressed_data, &decompressed_len, compressed_data, compressed_len);
+	CU_ASSERT(rc == 0);
+	CU_ASSERT(decompressed_len == 2048);
+	CU_ASSERT(memcmp(original_data, decompressed_data, decompressed_len) == 0);
+
+	compressed_len = sizeof(compressed_data);
+	rc = ut_compress(compressed_data, &compressed_len, original_data, 2049);
+	CU_ASSERT(rc == -ENOSPC);
+}
+
+int
+main(int argc, char **argv)
+{
+	CU_pSuite	suite = NULL;
+	unsigned int	num_failures;
+
+	CU_set_error_action(CUEA_ABORT);
+	CU_initialize_registry();
+
+	suite = CU_add_suite("reduce", NULL, NULL);
+
+	CU_ADD_TEST(suite, get_pm_file_size);
+	CU_ADD_TEST(suite, get_vol_size);
+	CU_ADD_TEST(suite, init_failure);
+	CU_ADD_TEST(suite, init_md);
+	CU_ADD_TEST(suite, init_backing_dev);
+	CU_ADD_TEST(suite, load);
+	CU_ADD_TEST(suite, write_maps);
+	CU_ADD_TEST(suite, read_write);
+	CU_ADD_TEST(suite, readv_writev);
+	CU_ADD_TEST(suite, destroy);
+	CU_ADD_TEST(suite, defer_bdev_io);
+	CU_ADD_TEST(suite, overlapped);
+	CU_ADD_TEST(suite, compress_algorithm);
+
+	g_unlink_path = g_path;
+	g_unlink_callback = unlink_cb;
+
+	CU_basic_set_mode(CU_BRM_VERBOSE);
+	CU_basic_run_tests();
+	num_failures = CU_get_number_of_failures();
+	CU_cleanup_registry();
+	return num_failures;
+}