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Based on kernel version 3.16. Page generated on 2014-08-06 21:39 EST.

1		  	    v9fs: Plan 9 Resource Sharing for Linux
2			    =======================================
3	
4	ABOUT
5	=====
6	
7	v9fs is a Unix implementation of the Plan 9 9p remote filesystem protocol.
8	
9	This software was originally developed by Ron Minnich <rminnich@sandia.gov>
10	and 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	
15	The best detailed explanation of the Linux implementation and applications of
16	the 9p client is available in the form of a USENIX paper:
17	   http://www.usenix.org/events/usenix05/tech/freenix/hensbergen.html
18	
19	Other 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	
31	USAGE
32	=====
33	
34	For remote file server:
35	
36		mount -t 9p 10.10.1.2 /mnt/9
37	
38	For 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	
42	For server running on QEMU host with virtio transport:
43	
44		mount -t 9p -o trans=virtio <mount_tag> /mnt/9
45	
46	where mount_tag is the tag associated by the server to each of the exported
47	mount points. Each 9P export is seen by the client as a virtio device with an
48	associated "mount_tag" property. Available mount tags can be
49	seen by reading /sys/bus/virtio/drivers/9pnet_virtio/virtio<n>/mount_tag files.
50	
51	OPTIONS
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	
136	RESOURCES
137	=========
138	
139	Protocol specifications are maintained on github:
140	http://ericvh.github.com/9p-rfc/
141	
142	9p client and server implementations are listed on
143	http://9p.cat-v.org/implementations
144	
145	A 9p2000.L server is being developed by LLNL and can be found
146	at http://code.google.com/p/diod/
147	
148	There are user and developer mailing lists available through the v9fs project
149	on sourceforge (http://sourceforge.net/projects/v9fs).
150	
151	News and other information is maintained on a Wiki.
152	(http://sf.net/apps/mediawiki/v9fs/index.php).
153	
154	Bug reports are best issued via the mailing list.
155	
156	For more information on the Plan 9 Operating System check out
157	http://plan9.bell-labs.com/plan9
158	
159	For information on Plan 9 from User Space (Plan 9 applications and libraries
160	ported to Linux/BSD/OSX/etc) check out http://swtch.com/plan9
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