filtered out / handled by the kernel. Access modes (O_RDONLY, O_WRONLY, O_RDWR) should be used by the filesystem to check if the operation is permitted. If the -o default_permissions mount option is given, this open() and may thus be omitted by the filesystem. When writeback caching is enabled, the kernel may send read requests even for files opened with O_WRONLY. The filesystem should be prepared to handle this this. When writeback caching is disabled, the filesystem is expected to properly handle the O_APPEND flag and ensure that each write is appending to the end of the file. When writeback caching is enabled,

{ TrimStop(); } int Init(const std::string cacheDir); int Write(std::string name, const char* buf, uint64_t length); int Read(std::string name, char* buf, uint64_t offset, uint64_t length); int CreateDir(); uint64_t GetCachedSize(); std::string GetCacheDir(); std::string GetCacheReadFullDir(); std::string GetCacheWriteFullDir(); /** * @brief tell whether whether the obj is cached in local cache disk. */ bool IsCached(std::string name); void addCache(std::string name); /** * @brief tell whether the cache disk is full or not. */

int nlink; /* ref count for hard link */ int64_t size; FileType type; SpaceList std::map; // string symLink; /* for symLink only */ inodeid key std::unordered_map inodeMap_; // inode ::curve::common::RWLock lock_;© XXX Page 9 of 24 }; class DentryKey { uint64_t fsId; InodeId parentId; std::string name; List(const DentryParentKey &key, std::list); void Delete(const DentryKey &key); void Update(const Dentry &dentry); DentryKey GetKey(InodeId parentId, std::string &name); int Count();

ClientS3Adaptor () {} void Init(const S3ClientAdaptorOption option, S3Client *client, std::shared_ptr inodeManager);© XXX Page 5 of 9 int Write(Inode *inode, uint64_t offset, uint64_t chunkSize_; std::string metaServerEps_; std::string allocateServerEps_; Thread bgFlushThread_; std::atomic toStop_; std::shared_ptr fsCacheManager_; std::shared_ptr inodeManager_; FileCacheManager; class FsCacheManager; using FileCacheManagerPtr = std::shared_ptr; using ChunkCacheManagerPtr = std::shared_ptr; using DataCachePtr = std::shared_ptr; class FsCacheManager { public: FsCacheManager()

public: bool Init(); int Set(const std::string& key, const std::string& value); int Get(const std::string& key, std::string* value); int Delete(const std::string& key); int Save(); // private: std::string EncodeJournal(OpType opType, const std::string& key, const std::string& value=""); bool WriteJournal(const std::string& message); private: map<std::string, std::string> Hash; Hash; // B+ std::string filePtah; // WAL dump (WAL : curvefs.waldump : curvefs.dump) }; Q&A© XXX Page 9 of 12 单靠 redis 的 AOF 机制能否保证数据不丢失? 不能，因为 AOF 与 SET/DEL 这些操作不是同步进行的，即使刷入文件配置项 开启最高级别的

virtual int Upload(std::string name, const char* buf, uint64_t length) = 0; virtual int Append(std::string name, const char* buf, uint64_t length) = 0; virtual int Download(std::string name, char* uint64_t NextChunkId() { auto id = chunkId_.fetch_add(1, std::memory_order_relaxed); return id; } private: std::atomic chunkId_;© XXX Page 10 of 11 }; 关键流程 关键流程包括

程负责发送 86.4K -> 130KCLIENT性能优化  发送RPC耗时较长  增加发送线程个数  在bthread协程中使用std::mutex/spinlock，在大量并发的情况下，会阻塞worker线程，也 存在瓶颈  std::mutex/spinlock 改成 bthread::Mutex  …… 128深度、4K随机写欢 迎 大 家 参 与 C U R V

bvar::LatencyRecorder : 专用于记录延时和qps的变量。  bvar::Maxer : 记录最大值，默认std::numeric_limits::min()， varname << N相当于varname = max(varname, N)。  bvar::Miner : 记录最小值，默认std::numeric_limits::max()， varname << N相当于varname =

rightOffset = 0; }; struct Extent { uint64_t offset = 0; uint32_t len = 0; }; using Extents = std::vector; class Allocator { public: Allocator(...) {} virtual ~Allocator() = default;©

●BRPC是Curve的基础通讯框架 ●支持远程过程调用 –C++ –TCP传输 –bthread协程(m:n调度，减少基于内核的下文切换 ，减少cache miss) ●多协议支持 –baidu_std,http,grpc… ●protobuf3 BRPC简介 ●Client/Server架构 ●使用Protobuf定义协议文件 –例如: echo.proto:4 BRPC简介 client