Annotation of wikisrc/puffs.mdwn, revision 1.4
1.1 jdf 1: **Contents**
2:
3: [[!toc levels=2]]
4:
5: # Filesystems in userspace: puffs, refuse, FUSE, and more
6:
7: ## About
8:
9: NetBSD now offers full support for running file systems in userspace. Major
10: components are "puffs", which is the kernel subsystem that realizes the
11: pass-to-userspace framework file system, as well as the userland libraries that
12: support constructing file system implementations. These are libpuffs and the
13: FUSE compatibility library, librefuse.
14:
15: This page describes the situation in NetBSD 5.0 and later.
16:
17: ## Components
18:
19: There are a number of components interacting to provide routines for userland
20: file systems: puffs as the kernel part, and libpuffs and librefuse to provide
21: functions for userland file systems to call. The following image gives an
22: overview of the components and their connections:
23:
1.3 jdf 24: 
1.1 jdf 25: **Overview about puffs**
26:
27: The components themselves are:
28:
29: * **puffs** is the core component inside the kernel. It exposes a file system
30: interface towards the userland programs (accessible via `/dev/puffs` and
31: libpuffs), and communicates with the kernel's own idea of files, which are
32: represented as vnodes. The puffs kernel component and how to interface it is
33: described further in the MAN.PUFFS.4 manpage.
34:
35: * The **libpuffs** library is the interface between userland file systems
36: and the kernel component. It provides a number of convenience routines that
37: userland file systems can use, and is described in the MAN.PUFFS.3 manpage.
38:
39: * To facilitate running the huge amount of file systems already available for
40: the FUSE interface, but not dictate the capabilities of puffs by it, it was
41: decided that FUSE support should be provided as a compatibility layer on top
42: of the native puffs interface, which is offered by **librefuse**. The
43: re-implementation of the FUSE functionality is designed to be source code
44: compatible with FUSE, and it is further described in the
1.4 ! kim 45: [[!template id=man name="refuse" section="3"]]
1.1 jdf 46: manpage.
47:
48: Examples for puffs and refuse filesystems can be found in the the NetBSD source
49: tree in `src/share/examples/{puffs,refuse}`.
50:
51: ## Enabling puffs
52:
53: puffs is enabled by default in GENERIC on major architectures starting from
54: NetBSD 5.0. For a custom kernel, the following are required in the kernel
55: configuration.
56:
57: file-system PUFFS
58: pseudo-device putter
59:
60: Alternatively, modules can be used.
61:
62: ## Base system examples
63:
64: This section presents usage examples for file systems shipped with the NetBSD
65: base system.
66:
67: ### psshfs, The NetBSD sshfs
68:
69: See the manpage for
1.4 ! kim 70: [[!template id=man name="mount_psshfs" section="8"]].
1.1 jdf 71:
72: # mount_psshfs host.name.tld:/directory /puffs
73: # ls /puffs
74: AdobeFnt.lst OS bin public_html
75: Desktop OpenOffice.org1.1.0 in tmp
76: ...
77: # cd /puffs
78: # ls -l .cshrc
79: -rw-r--r-- 1 39068 2000 4706 Jun 16 01:01 .cshrc
80: # head -2 .cshrc
81: # Default .cshrc for Solaris, Irix, ...
82: #
83: # md5 .cshrc
84: MD5 (.cshrc) = 2ad1d2606a5678f312709a388376c2e5
85: # ls -l test
86: ls: test: No such file or directory
87: # date >test
88: # ls -l test
89: -rw-r--r-- 1 39068 2000 29 Nov 23 01:19 test
90: # cat test
91: Thu Nov 23 01:19:36 MET 2006
92: # umount /puffs
93:
94: ### 9P file servers
95:
96: See the [Bell manpage](http://www.cs.bell-labs.com/sys/man/5/INDEX.html) and
1.4 ! kim 97: the NetBSD manpage [[!template id=man name="mount_9p" section="8"]].
1.1 jdf 98:
99: # mount_9p nobody@192.168.1.2:/tmp /puffs
100: # cd /puffs
101: # echo 9puffs in action > msg_from_earth
102: # ls -l msg_from_earth
103: -rw-r--r-- 1 nobody wheel 17 Apr 25 23:24 msg_from_earth
104: # rsh 192.168.1.2 cat /tmp/msg_from_earth
105: 9puffs in action
106:
107: Since there is currently no support in the implementation for access control or
108: support for authentication, the account nobody was picked just to prove a point.
109: The NFS nobody user really does not have anything to do with 9P. Support for
110: access control and use of pre-established secure connections will be added to
111: `mount_9p` on a later date.
112:
113: ## pkgsrc & FUSE
114:
115: FUSE compatibility was added within pkgsrc, and besides the required
116: infrastructure work a number of FUSE packages were added to pkgsrc in the new
117: *filesystem* category. Example packages that are currently available include:
118:
119: * [fuse](ftp://ftp.netbsd.org/pub/pkgsrc/current/pkgsrc/filesystems/fuse/README.html)
120: -- filesystem in userspace (compat headers, pkg-config files, etc.), needed for
121: pkgsrc on Linux
122:
123: * [fuse-archivemount](ftp://ftp.netbsd.org/pub/pkgsrc/current/pkgsrc/filesystems/fuse-archivemount/README.html)
124: -- FUSE gateway to libarchive
125:
126: * [fuse-cddfs](ftp://ftp.netbsd.org/pub/pkgsrc/current/pkgsrc/filesystems/fuse-cddfs/README.html)
127: -- FUSE filesystem that uses libparanoia for audio CDs
128:
129: * [fuse-ntfs-3g](ftp://ftp.netbsd.org/pub/pkgsrc/current/pkgsrc/filesystems/fuse-ntfs-3g/README.html)
130: -- a NTFS driver with read and write support
131:
132: * ...
133:
134: More packages are currently being worked on, please see
135: [pkgsrc/filesystems](ftp://ftp.NetBSD.org/pub/pkgsrc/current/pkgsrc/filesystems/README.html)
136: for a full list.
137:
138: Here is an example of installing and using the FUSE-enabled NTFS-3g
139: implementation:
140:
141: # cd pkgsrc/filesystems/fuse-ntfs-3g
142: # make install
143: # ntfs-3g ntfs.img /ntfs
144:
145: Using FUSE file systems on NetBSD 4.0 is possible, but in addition to adding
146: puffs support support to the kernel, it requires fetching and manually
147: installing a backport of the ReFUSE library. The library is available
148: [here](http://www.cs.hut.fi/~pooka/NetBSD/librefuse_nb4-20080115.tar.gz)
149: and further instructions are available
150: [here](http://mail-index.NetBSD.org/netbsd-users/2008/01/15/msg000075.html).
151:
152: ## Further Information
153:
154: An in-depth technical description of puffs was presented at
155: [AsiaBSDCon](http://www.asiabsdcon.org/) 2007 in a paper entitled
156: *puffs - Pass-to-Userspace Framework File System*. The
157: [paper](http://2007.asiabsdcon.org/papers/P04-paper.pdf) and
158: [slides](http://2007.asiabsdcon.org/papers/P04-slides.pdf) are available.
159:
160: The ReFUSE emulation layer for FUSE file systems is described in
1.2 jdf 161: *[ReFUSE: Userspace FUSE Reimplementation Using puffs](/puffs/refuse.pdf)*
1.1 jdf 162: presented at EuroBSDCon 2007.
163:
164: A [paper](http://2008.asiabsdcon.org/papers/P4B-paper.pdf) discussing the
165: implementation of distributed file systems on top of puffs was presented at
166: AsiaBSDCon 2008.
167:
1.4 ! kim 168: The [[!template id=man name="puffs" section="3"]] manual pages provide further
1.1 jdf 169: information from a development perspective.
170:
171: The source code in browsable form:
172:
173: * [kernel code](http://cvsweb.netbsd.org/bsdweb.cgi/src/sys/fs/puffs/)
174: * [libpuffs](http://cvsweb.netbsd.org/bsdweb.cgi/src/lib/libpuffs/)
175: * [librefuse](http://cvsweb.netbsd.org/bsdweb.cgi/src/lib/librefuse/)
176: * [puffs file systems in the base system](http://cvsweb.netbsd.org/bsdweb.cgi/src/usr.sbin/puffs/)
177: * [source code examples of other puffs file systems](http://cvsweb.netbsd.org/bsdweb.cgi/src/share/examples/puffs/)
178: * [source code examples for refuse](http://cvsweb.netbsd.org/bsdweb.cgi/src/share/examples/refuse/)
179:
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