About Kernel Documentation Linux Kernel Contact Linux Resources Linux Blog

Documentation / filesystems / 9p.txt




Custom Search

Based on kernel version 3.13. Page generated on 2014-01-20 22:02 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				loose = no attempts are made at consistency,
73	                                intended for exclusive, read-only mounts
74				fscache = use FS-Cache for a persistent, read-only
75					cache backend.
76	
77	  debug=n	specifies debug level.  The debug level is a bitmask.
78				0x01  = display verbose error messages
79				0x02  = developer debug (DEBUG_CURRENT)
80				0x04  = display 9p trace
81				0x08  = display VFS trace
82				0x10  = display Marshalling debug
83				0x20  = display RPC debug
84				0x40  = display transport debug
85				0x80  = display allocation debug
86				0x100 = display protocol message debug
87				0x200 = display Fid debug
88				0x400 = display packet debug
89				0x800 = display fscache tracing debug
90	
91	  rfdno=n	the file descriptor for reading with trans=fd
92	
93	  wfdno=n	the file descriptor for writing with trans=fd
94	
95	  msize=n	the number of bytes to use for 9p packet payload
96	
97	  port=n	port to connect to on the remote server
98	
99	  noextend	force legacy mode (no 9p2000.u or 9p2000.L semantics)
100	
101	  version=name	Select 9P protocol version. Valid options are:
102				9p2000          - Legacy mode (same as noextend)
103				9p2000.u        - Use 9P2000.u protocol
104				9p2000.L        - Use 9P2000.L protocol
105	
106	  dfltuid	attempt to mount as a particular uid
107	
108	  dfltgid	attempt to mount with a particular gid
109	
110	  afid		security channel - used by Plan 9 authentication protocols
111	
112	  nodevmap	do not map special files - represent them as normal files.
113	  		This can be used to share devices/named pipes/sockets between
114			hosts.  This functionality will be expanded in later versions.
115	
116	  access	there are four access modes.
117				user  = if a user tries to access a file on v9fs
118				        filesystem for the first time, v9fs sends an
119				        attach command (Tattach) for that user.
120					This is the default mode.
121				<uid> = allows only user with uid=<uid> to access
122					the files on the mounted filesystem
123				any   = v9fs does single attach and performs all
124					operations as one user
125				client = ACL based access check on the 9p client
126				         side for access validation
127	
128	  cachetag	cache tag to use the specified persistent cache.
129			cache tags for existing cache sessions can be listed at
130			/sys/fs/9p/caches. (applies only to cache=fscache)
131	
132	RESOURCES
133	=========
134	
135	Protocol specifications are maintained on github:
136	http://ericvh.github.com/9p-rfc/
137	
138	9p client and server implementations are listed on
139	http://9p.cat-v.org/implementations
140	
141	A 9p2000.L server is being developed by LLNL and can be found
142	at http://code.google.com/p/diod/
143	
144	There are user and developer mailing lists available through the v9fs project
145	on sourceforge (http://sourceforge.net/projects/v9fs).
146	
147	News and other information is maintained on a Wiki.
148	(http://sf.net/apps/mediawiki/v9fs/index.php).
149	
150	Bug reports may be issued through the kernel.org bugzilla 
151	(http://bugzilla.kernel.org)
152	
153	For more information on the Plan 9 Operating System check out
154	http://plan9.bell-labs.com/plan9
155	
156	For information on Plan 9 from User Space (Plan 9 applications and libraries
157	ported to Linux/BSD/OSX/etc) check out http://swtch.com/plan9
158	
159	
160	STATUS
161	======
162	
163	The 2.6 kernel support is working on PPC and x86.
164	
165	PLEASE USE THE KERNEL BUGZILLA TO REPORT PROBLEMS. (http://bugzilla.kernel.org)
Hide Line Numbers
About Kernel Documentation Linux Kernel Contact Linux Resources Linux Blog

Information is copyright its respective author. All material is available from the Linux Kernel Source distributed under a GPL License. This page is provided as a free service by mjmwired.net.