）中指向这个打开的文件。打开的文件描述符记录中保存着文件的offset 和 文件status。 每个进程都有个 task_struct 描述符用来描述进程相关的信息，其中有个 files_struct 类型的 files 字段，里面有个保存了当前进程所有已打开文件 描述符的数组，而通过 fd 就可以找到具体的文件描述符:© XXX Page 3 of 23 open & openat 系统调用 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. When writeback caching is

file structure of virtual block device As mentioned above, CurveBS maps virtual block devices to files. Let's look at the metadata for a file in CurveBS. 1. A file in CurveBS consists of chunks interface based on FUSE. 1. Fs-meta Cluster is used to manage the inode and dentry metadata of files. The architecture is like CurveBS, so metadata scalability is very good in this way. 2. Fs-data

file access to the filesystem owner, so that all users (including root) can access the files. allow_root This option is similar to allow_other but file access is limited effective rights -E, --no-effective print no effective rights -s, --skip-base skip files that only have the base entries -R, --recursive recurse into subdirectories -L, --logical

instance on a physical serverCurve metadata organization Curve maps virtual block devices to files Each file contains chunks scattered across storage nodes in the cluster Chunkservers are grouped