Module vfs

A union file system which combines multiple backend file systems into one.

A simple union file system with limited functionality, which

1. uses pseudo fs to maintain the directory structures
2. supports mounting a file system at “/” or and subdirectory
3. supports mounting multiple file systems at different paths
4. remounting another file system at the same path will evict the old one
5. doesn’t support recursive mounts. If /a is a mounted file system, you can’t mount another file systems under /a.

Its main usage is to avoid virtio-fs device hotplug. With this simple union fs, a new backend file system could be mounted onto a subdirectory, instead of hot-adding another virtio-fs device. This is very convenient to manage container images at runtime.

Structs

Vfs

A union fs that combines multiple backend file systems.

VfsInode

Data struct to store inode number for the VFS filesystem.

VfsOptions

vfs init options

Enums

VfsError

Vfs error definition

Constants

CURRENT_DIR_CSTR

Current directory

EMPTY_CSTR

Emptry CSTR

PARENT_DIR_CSTR

Parent directory

PROC_SELF_FD_CSTR

Proc fd directory

SLASH_ASCII

ASCII for slash(‘/’)

VFS_MAX_INO

Maximum inode number supported by the VFS for backend file system

Traits

BackendFileSystem

BackendFileSystem abstracts all backend file systems under vfs

Functions

validate_path_component

Validate a path component. A well behaved FUSE client should never send dot, dotdot and path components containing slash (‘/’). The only exception is that LOOKUP might contain dot and dotdot to support NFS export.

Type Aliases

BackFileSystem

Type that implements BackendFileSystem and Sync and Send

VfsIndex

Vfs backend file system index

VfsResult

Vfs result