CurveBS I/O processing flow Before introducing IO processing flow, we first describe the overall architecture, data organization and topology structure of CURVE. CurveBS uses the central interface, such as read/write/aioread/aiowrite in data plane and open/create/rename/extend, etc in control plane. 2. Depending on libCurve, the application must be restarted every time the library is the NEBDServer, which affects services in few seconds. CurveBS IO processing flow Overall process The flow of user's read and write request to curve: 1. The user initiates a request (fd=1

CurveBS Data Organization • MetaData Server (MDS) • ChunkServer • Client • CurveBS IO processing flow • CurveBS Performance considerations • Cloud NativeAgenda • CurveFS Architecture • CurveFS Organization • CurveFS file Organization • CurveFS MetaServer • CurveFS Client • CurveFS MKNode Flow • CurveFS Write to S3 FlowCurveBS ArchitectureCurveBS TopologyCurveBS Data OrganizationMetaData

二、文件系统权限管理 文件类型 文件权限 特殊权限(SUID, SGID, STICKY) 文件默认权限umask 用户&用户组 文件系统用户权限管理 对mode的管理 对ACL（Access Control Lists）的管理 ACL Access Entry保存在哪？ ACL的表示 内存中的ACL 是如何与具体的 Inode 相关联 如何存储和获取ACL信息 Inode权限校验 chmod、 umask; }; // in fuse_lowlevel.h is const struct fuse_ctx *fuse_req_ctx(fuse_req_t req) 对ACL（Access Control Lists）的管理 访问控制列表（ACL 或 POSIX ACL）是多用户系统的 。 与基本的 POSIX RWX 位相比，POSIX ACL 有助于对文件系统权限进行 的控制。可以针对用户（User）、群组（Group） file access control lists Usage: getfacl [-aceEsRLPtpndvh] file ... -a, --access display the file access control list only -d, --default display the default access control list only