ce67e0c787
This is the beginning of support for external snapshots. An external
snapshot is a read-only blobstore device (struct spdk_bs_dev) that can
be used as a blob's back device. Normally a blob will have no back
device (a normal blob), a zeroes back device (a thin provisioned blob),
or a blob back device (a clone blob). When a blob has an external
snapshot ("esnap") as its back device, it is called an esnap clone.
With this patch, esnap clones can be created but they are not yet
useful. Subsequent patches in the series will plumb the IO path, enable
various features, and allow lvol bdevs to be esnap clones.
Signed-off-by: Mike Gerdts <mgerdts@nvidia.com>
Change-Id: I29206b628a2b03b6386a88532565e228df988e0e
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/14969
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Shuhei Matsumoto <smatsumoto@nvidia.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
109 lines
2.6 KiB
C
109 lines
2.6 KiB
C
/* SPDX-License-Identifier: BSD-3-Clause
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* Copyright (c) 2022-2023 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
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*/
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#include "spdk/stdinc.h"
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#include "spdk_cunit.h"
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#include "spdk/blob.h"
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/*
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* This creates a bs_dev that does not depend on a bdev. Typical use without assertions looks like:
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*
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* struct spdk_bs_dev *dev;
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* struct spdk_bs_opts bs_opts;
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* struct spdk_blob_opts blob_opts;
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* struct ut_snap_opts esnap_opts;
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*
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* Create the blobstore with external snapshot support.
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* dev = init_dev();
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* memset(g_dev_buffer, 0, DEV_BUFFER_SIZE);
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* spdk_bs_opts_init(&bs_opts, sizeof(bs_opts));
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* bs_opts.esnap_bs_dev_create = ut_esnap_create;
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*
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* Create an esnap clone blob.
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* ut_spdk_blob_opts_init(&blob_opts);
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* ut_esnap_opts_init(512, 2048, "name", &esnap_opts);
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* blob_opts.esnap_id = &esnap_opts;
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* blob_opts.esnap_id_len = sizeof(esnap_opts);
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* opts.num_clusters = 4;
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* blob = ut_blob_create_and_open(bs, &opts);
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*
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* At this point the blob can be used like any other blob.
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*/
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#define UT_ESNAP_OPTS_MAGIC 0xbadf1ea5
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struct ut_esnap_opts {
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/*
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* This structure gets stored in an xattr. The magic number is used to give some assurance
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* that we got the right thing before trying to use the other fields.
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*/
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uint32_t magic;
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uint32_t block_size;
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uint64_t num_blocks;
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char name[32];
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};
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struct ut_esnap_dev {
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struct spdk_bs_dev bs_dev;
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struct ut_esnap_opts ut_opts;
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spdk_blob_id blob_id;
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uint32_t num_channels;
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};
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static void
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ut_esnap_opts_init(uint32_t block_size, uint32_t num_blocks, const char *name,
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struct ut_esnap_opts *opts)
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{
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memset(opts, 0, sizeof(*opts));
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opts->magic = UT_ESNAP_OPTS_MAGIC;
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opts->block_size = block_size;
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opts->num_blocks = num_blocks;
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spdk_strcpy_pad(opts->name, name, sizeof(opts->name) - 1, '\0');
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}
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static void
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ut_esnap_destroy(struct spdk_bs_dev *bs_dev)
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{
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free(bs_dev);
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}
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static struct spdk_bs_dev *
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ut_esnap_dev_alloc(const struct ut_esnap_opts *opts)
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{
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struct ut_esnap_dev *ut_dev;
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struct spdk_bs_dev *bs_dev;
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assert(opts->magic == UT_ESNAP_OPTS_MAGIC);
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ut_dev = calloc(1, sizeof(*ut_dev));
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if (ut_dev == NULL) {
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return NULL;
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}
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ut_dev->ut_opts = *opts;
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bs_dev = &ut_dev->bs_dev;
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bs_dev->blocklen = opts->block_size;
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bs_dev->blockcnt = opts->num_blocks;
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bs_dev->destroy = ut_esnap_destroy;
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return bs_dev;
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}
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static int
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ut_esnap_create(struct spdk_blob *blob, const void *id, uint32_t id_len,
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struct spdk_bs_dev **bs_devp)
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{
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struct spdk_bs_dev *bs_dev = NULL;
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SPDK_CU_ASSERT_FATAL(id != NULL);
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SPDK_CU_ASSERT_FATAL(sizeof(struct ut_esnap_opts) == id_len);
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bs_dev = ut_esnap_dev_alloc(id);
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SPDK_CU_ASSERT_FATAL(bs_dev != NULL);
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*bs_devp = bs_dev;
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return 0;
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}
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