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1 v9fs: Plan 9 Resource Sharing for Linux
2 =======================================
3
4ABOUT
5=====
6
7v9fs is a Unix implementation of the Plan 9 9p remote filesystem protocol.
8
9This software was originally developed by Ron Minnich <rminnich@sandia.gov>
10and Maya Gokhale. Additional development by Greg Watson
11<gwatson@lanl.gov> and most recently Eric Van Hensbergen
12<ericvh@gmail.com>, Latchesar Ionkov <lucho@ionkov.net> and Russ Cox
13<rsc@swtch.com>.
14
15The best detailed explanation of the Linux implementation and applications of
16the 9p client is available in the form of a USENIX paper:
17 http://www.usenix.org/events/usenix05/tech/freenix/hensbergen.html
18
19Other applications are described in the following papers:
20 * XCPU & Clustering
21 http://xcpu.org/papers/xcpu-talk.pdf
22 * KVMFS: control file system for KVM
23 http://xcpu.org/papers/kvmfs.pdf
24 * CellFS: A New Programming Model for the Cell BE
25 http://xcpu.org/papers/cellfs-talk.pdf
26 * PROSE I/O: Using 9p to enable Application Partitions
27 http://plan9.escet.urjc.es/iwp9/cready/PROSE_iwp9_2006.pdf
28 * VirtFS: A Virtualization Aware File System pass-through
29 http://goo.gl/3WPDg
30
31USAGE
32=====
33
34For remote file server:
35
36 mount -t 9p 10.10.1.2 /mnt/9
37
38For Plan 9 From User Space applications (http://swtch.com/plan9)
39
40 mount -t 9p `namespace`/acme /mnt/9 -o trans=unix,uname=$USER
41
42For server running on QEMU host with virtio transport:
43
44 mount -t 9p -o trans=virtio <mount_tag> /mnt/9
45
46where mount_tag is the tag associated by the server to each of the exported
47mount points. Each 9P export is seen by the client as a virtio device with an
48associated "mount_tag" property. Available mount tags can be
49seen by reading /sys/bus/virtio/drivers/9pnet_virtio/virtio<n>/mount_tag files.
50
51OPTIONS
52=======
53
54 trans=name select an alternative transport. Valid options are
55 currently:
56 unix - specifying a named pipe mount point
57 tcp - specifying a normal TCP/IP connection
58 fd - used passed file descriptors for connection
59 (see rfdno and wfdno)
60 virtio - connect to the next virtio channel available
61 (from QEMU with trans_virtio module)
62 rdma - connect to a specified RDMA channel
63
64 uname=name user name to attempt mount as on the remote server. The
65 server may override or ignore this value. Certain user
66 names may require authentication.
67
68 aname=name aname specifies the file tree to access when the server is
69 offering several exported file systems.
70
71 cache=mode specifies a caching policy. By default, no caches are used.
72 none = default no cache policy, metadata and data
73 alike are synchronous.
74 loose = no attempts are made at consistency,
75 intended for exclusive, read-only mounts
76 fscache = use FS-Cache for a persistent, read-only
77 cache backend.
78 mmap = minimal cache that is only used for read-write
79 mmap. Northing else is cached, like cache=none
80
81 debug=n specifies debug level. The debug level is a bitmask.
82 0x01 = display verbose error messages
83 0x02 = developer debug (DEBUG_CURRENT)
84 0x04 = display 9p trace
85 0x08 = display VFS trace
86 0x10 = display Marshalling debug
87 0x20 = display RPC debug
88 0x40 = display transport debug
89 0x80 = display allocation debug
90 0x100 = display protocol message debug
91 0x200 = display Fid debug
92 0x400 = display packet debug
93 0x800 = display fscache tracing debug
94
95 rfdno=n the file descriptor for reading with trans=fd
96
97 wfdno=n the file descriptor for writing with trans=fd
98
99 msize=n the number of bytes to use for 9p packet payload
100
101 port=n port to connect to on the remote server
102
103 noextend force legacy mode (no 9p2000.u or 9p2000.L semantics)
104
105 version=name Select 9P protocol version. Valid options are:
106 9p2000 - Legacy mode (same as noextend)
107 9p2000.u - Use 9P2000.u protocol
108 9p2000.L - Use 9P2000.L protocol
109
110 dfltuid attempt to mount as a particular uid
111
112 dfltgid attempt to mount with a particular gid
113
114 afid security channel - used by Plan 9 authentication protocols
115
116 nodevmap do not map special files - represent them as normal files.
117 This can be used to share devices/named pipes/sockets between
118 hosts. This functionality will be expanded in later versions.
119
120 access there are four access modes.
121 user = if a user tries to access a file on v9fs
122 filesystem for the first time, v9fs sends an
123 attach command (Tattach) for that user.
124 This is the default mode.
125 <uid> = allows only user with uid=<uid> to access
126 the files on the mounted filesystem
127 any = v9fs does single attach and performs all
128 operations as one user
129 client = ACL based access check on the 9p client
130 side for access validation
131
132 cachetag cache tag to use the specified persistent cache.
133 cache tags for existing cache sessions can be listed at
134 /sys/fs/9p/caches. (applies only to cache=fscache)
135
136RESOURCES
137=========
138
139Protocol specifications are maintained on github:
140http://ericvh.github.com/9p-rfc/
141
1429p client and server implementations are listed on
143http://9p.cat-v.org/implementations
144
145A 9p2000.L server is being developed by LLNL and can be found
146at http://code.google.com/p/diod/
147
148There are user and developer mailing lists available through the v9fs project
149on sourceforge (http://sourceforge.net/projects/v9fs).
150
151News and other information is maintained on a Wiki.
152(http://sf.net/apps/mediawiki/v9fs/index.php).
153
154Bug reports are best issued via the mailing list.
155
156For more information on the Plan 9 Operating System check out
157http://plan9.bell-labs.com/plan9
158
159For information on Plan 9 from User Space (Plan 9 applications and libraries
160ported to Linux/BSD/OSX/etc) check out http://swtch.com/plan9
161