blob: Add a bs_dev that always returns 0

This will be useful for backing thin provisioned
blobs in the future.

Change-Id: I78cf8cda39e8dff42da69b79ed460797d7494af1
Signed-off-by: Ben Walker <benjamin.walker@intel.com>
Reviewed-on: https://review.gerrithub.io/397043
Reviewed-by: Daniel Verkamp <daniel.verkamp@intel.com>
Tested-by: SPDK Automated Test System <sys_sgsw@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>

lib/blob/Makefile

@@ -34,7 +34,7 @@
 SPDK_ROOT_DIR := $(abspath $(CURDIR)/../..)
 include $(SPDK_ROOT_DIR)/mk/spdk.common.mk
 
-C_SRCS = blobstore.c request.c
+C_SRCS = blobstore.c request.c zeroes.c
 LIBNAME = blob
 
 DIRS-y += bdev

lib/blob/blobstore.h

@@ -325,6 +325,8 @@ SPDK_STATIC_ASSERT(sizeof(struct spdk_bs_super_block) == 0x1000, "Invalid super
 
 #pragma pack(pop)
 
+struct spdk_bs_dev *spdk_bs_create_zeroes_dev(void);
+
 /* Unit Conversions
  *
  * The blobstore works with several different units:

lib/blob/zeroes.c

@@ -0,0 +1,122 @@
+/*-
+ *   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/blob.h"
+
+#include "blobstore.h"
+
+static void
+zeroes_destroy(struct spdk_bs_dev *bs_dev)
+{
+	return;
+}
+
+static void
+zeroes_read(struct spdk_bs_dev *dev, struct spdk_io_channel *channel, void *payload,
+	    uint64_t lba, uint32_t lba_count, struct spdk_bs_dev_cb_args *cb_args)
+{
+	memset(payload, 0, dev->blocklen * lba_count);
+	cb_args->cb_fn(cb_args->channel, cb_args->cb_arg, 0);
+}
+
+static void
+zeroes_write(struct spdk_bs_dev *dev, struct spdk_io_channel *channel, void *payload,
+	     uint64_t lba, uint32_t lba_count,
+	     struct spdk_bs_dev_cb_args *cb_args)
+{
+	cb_args->cb_fn(cb_args->channel, cb_args->cb_arg, -EPERM);
+	assert(false);
+}
+
+static void
+zeroes_readv(struct spdk_bs_dev *dev, struct spdk_io_channel *channel,
+	     struct iovec *iov, int iovcnt,
+	     uint64_t lba, uint32_t lba_count, struct spdk_bs_dev_cb_args *cb_args)
+{
+	int i;
+
+	for (i = 0; i < iovcnt; i++) {
+		memset(iov[i].iov_base, 0, iov[i].iov_len);
+	}
+
+	cb_args->cb_fn(cb_args->channel, cb_args->cb_arg, 0);
+}
+
+
+
+static void
+zeroes_writev(struct spdk_bs_dev *dev, struct spdk_io_channel *channel,
+	      struct iovec *iov, int iovcnt,
+	      uint64_t lba, uint32_t lba_count,
+	      struct spdk_bs_dev_cb_args *cb_args)
+{
+	cb_args->cb_fn(cb_args->channel, cb_args->cb_arg, -EPERM);
+	assert(false);
+}
+
+static void
+zeroes_write_zeroes(struct spdk_bs_dev *dev, struct spdk_io_channel *channel,
+		    uint64_t lba, uint32_t lba_count,
+		    struct spdk_bs_dev_cb_args *cb_args)
+{
+	cb_args->cb_fn(cb_args->channel, cb_args->cb_arg, 0);
+}
+
+static void
+zeroes_unmap(struct spdk_bs_dev *dev, struct spdk_io_channel *channel,
+	     uint64_t lba, uint32_t lba_count,
+	     struct spdk_bs_dev_cb_args *cb_args)
+{
+	cb_args->cb_fn(cb_args->channel, cb_args->cb_arg, 0);
+}
+
+static struct spdk_bs_dev g_zeroes_bs_dev = {
+	.blockcnt = UINT64_MAX,
+	.blocklen = SPDK_BS_PAGE_SIZE,
+	.create_channel = NULL,
+	.destroy_channel = NULL,
+	.destroy = zeroes_destroy,
+	.read = zeroes_read,
+	.write = zeroes_write,
+	.readv = zeroes_readv,
+	.writev = zeroes_writev,
+	.write_zeroes = zeroes_write_zeroes,
+	.unmap = zeroes_unmap,
+};
+
+struct spdk_bs_dev *
+spdk_bs_create_zeroes_dev(void)
+{
+	return &g_zeroes_bs_dev;
+}