spdk_blob_io_write 代码案例，以及参数说明-DPDK中文网

下面是一个使用SPDK（Storage Performance Development Kit）中的spdk_blob_io_write函数进行异步写入的简单示例代码：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "spdk/stdinc.h"
#include "spdk/env.h"
#include "spdk/blob_bdev.h"
#include "spdk/io_channel.h"

// 回调函数，在IO完成时被调用
static void write_complete(void *cb_arg, int bserrno)
{
    if (bserrno) {
        printf("Write operation failed with error: %d\n", bserrno);
    } else {
        printf("Write operation completed successfully.\n");
    }

    // 释放资源并退出应用程序
    spdk_app_stop(bserrno);
}

int main(int argc, char **argv)
{
    struct spdk_app_opts opts;
    struct spdk_blob_store *bs;
    struct spdk_bs_dev *dev;
    struct spdk_io_channel *channel;
    
    // 初始化 SPDK 应用程序选项
    spdk_app_opts_init(&opts);

    // 设置应用程序选项，如名称、配置文件路径等

	// ...

	// 启动 SPDK 应用程序，并初始化环境
	if (spdk_app_start(&opts, NULL, NULL) != 0) {
		fprintf(stderr, "Failed to start SPDK application.\n");
		return 1;
	}

	// 创建 Blob 存储设备
	dev = spdk_bdev_create_bs_dev("/path/to/block_device", NULL, NULL);
	if (!dev) {
	    fprintf(stderr, "Failed to create blob storage device.\n");
	    return 1;
	}

	// 打开 Blob 存储设备
	bs = spdk_bs_init(dev, NULL, NULL);
	if (!bs) {
	    fprintf(stderr, "Failed to open blob storage device.\n");
	    return 1;
	}

	// 创建 IO 通道
	channel = spdk_bs_alloc_io_channel(bs);
	if (!channel) {
	    fprintf(stderr, "Failed to allocate IO channel.\n");
	    return 1;
	}

    // 构造写入缓冲区和长度
    char *write_buffer = "Hello, SPDK!";
    size_t write_length = strlen(write_buffer);

    // 构造写入请求
    struct spdk_blob *blob;
    spdk_blob_id blobid = 0; // 假设 Blob ID 为0
    uint64_t offset = 0;     // 写入偏移量为0

    blob = spdk_bs_open_blob(bs, blobid);
    if (!blob) {
        fprintf(stderr, "Failed to open blob with ID: %lu\n", (unsigned long)blobid);
        return 1;
    }

	// 异步写入操作
	spdk_blob_io_write(blob, channel, write_buffer, offset, write_length,
			    write_complete, NULL);

	// 启动事件循环并等待应用程序退出
	spdk_app_run();

	// 清理资源
	spdk_bs_free_io_channel(channel);
	spdk_bs_unload(bs);
	spdk_bdev_close(dev);

	return 0;
}

spdk_blob_io_write函数的参数说明如下：