Module fuse_backend_rs::api::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