upspinfs

Documentation

Overview

Command upspinfs is a FUSE interface for Upspin. It presents Upspin files as a locally mounted file system.

If the config or flags specify a cache server endpoint and cacheserver is not running, upspinfs will attempt to start one. All the flags listed below are also passed to the cacheserver should one be started.

Usage:

upspinfs [flags] mountpoint

where 'mountpoint' is an existing directory upon which to mount the Upspin name space.

The flags are:

-cachedir directory
	'directory' will contain all file caches (default "$HOME/upspin")
-cachesize bytes
	max disk bytes for cache (default 5000000000)
-config file
	user's configuration file (default "$HOME/upspin/config")
-log level
	level of logging: debug, info, error, disabled (default info)
-writethrough
	make storage cache writethrough

Examples:

% mkdir $HOME/ufs
% upspinfs $HOME/ufs &
% ls -l $HOME/ufs/tester@tester.com
% ...
% killall -9 upspinfs
% umount $HOME/ufs

Limitations:

Uspinfs tries to present a Posix file system. However since Upspin semantics are different than Posix, some things will be different:

- Files always appear owned by the user who started upspinfs

- Permission bits are settable but are not stored in Upspin. After the final close of a file, when the kernel and FUSE decide to forget about the file, permissions will revert to 0700. The access to a file is determined by the intersection of the permission bits and the relevant Access file.

- While random access will work, the first time a file is opened for read, it is read in its entirety and cached locally.

- Hard links are really copy on write. The two names will refer to the original data until either file is changed. They will then diverge.