.. SPDX-License-Identifier: GPL-2.0
===========================
Coda Kernel-Venus Interface
===========================
.. Note::
This is one of the technical documents describing a component of
Coda -- this document describes the client kernel-Venus interface.
For more information:
http://www.coda.cs.cmu.edu
For user level software needed to run Coda:
ftp://ftp.coda.cs.cmu.edu
To run Coda you need to get a user level cache manager for the client,
named Venus, as well as tools to manipulate ACLs, to log in, etc. The
client needs to have the Coda filesystem selected in the kernel
configuration.
The server needs a user level server and at present does not depend on
kernel support.
The Venus kernel interface
Peter J. Braam
v1.0, Nov 9, 1997
This document describes the communication between Venus and kernel
level filesystem code needed for the operation of the Coda file sys-
tem. This document version is meant to describe the current interface
(version 1.0) as well as improvements we envisage.
.. Table of Contents
1. Introduction
2. Servicing Coda filesystem calls
3. The message layer
3.1 Implementation details
4. The interface at the call level
4.1 Data structures shared by the kernel and Venus
4.2 The pioctl interface
4.3 root
4.4 lookup
4.5 getattr
4.6 setattr
4.7 access
4.8 create
4.9 mkdir
4.10 link
4.11 symlink
4.12 remove
4.13 rmdir
4.14 readlink
4.15 open
4.16 close
4.17 ioctl
4.18 rename
4.19 readdir
4.20 vget
4.21 fsync
4.22 inactive
4.23 rdwr
4.24 odymount
4.25 ody_lookup
4.26 ody_expand
4.27 prefetch
4.28 signal
5. The minicache and downcalls
5.1 INVALIDATE
5.2 FLUSH
5.3 PURGEUSER
5.4 ZAPFILE
5.5 ZAPDIR
5.6 ZAPVNODE
5.7 PURGEFID
5.8 REPLACE
6. Initialization and cleanup
6.1 Requirements
1. Introduction
===============
A key component in the Coda Distributed File System is the cache
manager, Venus.
When processes on a Coda enabled system access files in the Coda
filesystem, requests are directed at the filesystem layer in the
operating system. The operating system will communicate with Venus to
service the request for the process. Venus manages a persistent
client cache and makes remote procedure calls to Coda file servers and
related servers (such as authentication servers) to service these
requests it receive
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