v9fs: Plan 9 Resource Sharing for Linux ======================================= ABOUT ===== v9fs is a Unix implementation of the Plan 9 9p remote filesystem protocol. This software was originally developed by Ron Minnich and Maya Gokhale. Additional development by Greg Watson and most recently Eric Van Hensbergen , Latchesar Ionkov and Russ Cox . The best detailed explanation of the Linux implementation and applications of the 9p client is available in the form of a USENIX paper: http://www.usenix.org/events/usenix05/tech/freenix/hensbergen.html Other applications are described in the following papers: * XCPU & Clustering http://xcpu.org/papers/xcpu-talk.pdf * KVMFS: control file system for KVM http://xcpu.org/papers/kvmfs.pdf * CellFS: A New Programming Model for the Cell BE http://xcpu.org/papers/cellfs-talk.pdf * PROSE I/O: Using 9p to enable Application Partitions http://plan9.escet.urjc.es/iwp9/cready/PROSE_iwp9_2006.pdf USAGE ===== For remote file server: mount -t 9p 10.10.1.2 /mnt/9 For Plan 9 From User Space applications (http://swtch.com/plan9) mount -t 9p `namespace`/acme /mnt/9 -o trans=unix,uname=$USER For server running on QEMU host with virtio transport: mount -t 9p -o trans=virtio /mnt/9 where mount_tag is the tag associated by the server to each of the exported mount points. Each 9P export is seen by the client as a virtio device with an associated "mount_tag" property. Available mount tags can be seen by reading /sys/bus/virtio/drivers/9pnet_virtio/virtio/mount_tag files. OPTIONS ======= trans=name select an alternative transport. Valid options are currently: unix - specifying a named pipe mount point tcp - specifying a normal TCP/IP connection fd - used passed file descriptors for connection (see rfdno and wfdno) virtio - connect to the next virtio channel available (from QEMU with trans_virtio module) rdma - connect to a specified RDMA channel uname=name user name to attempt mount as on the remote server. The server may override or ignore this value. Certain user names may require authentication. aname=name aname specifies the file tree to access when the server is offering several exported file systems. cache=mode specifies a caching policy. By default, no caches are used. loose = no attempts are made at consistency, intended for exclusive, read-only mounts fscache = use FS-Cache for a persistent, read-only cache backend. debug=n specifies debug level. The debug level is a bitmask. 0x01 = display verbose error messages 0x02 = developer debug (DEBUG_CURRENT) 0x04 = display 9p trace 0x08 = display VFS trace 0x10 = display Marshalling debug 0x20 = display RPC debug 0x40 = display transport debug 0x80 = display allocation debug 0x100 = display protocol message debug 0x200 = display Fid debug 0x400 = display packet debug 0x800 = display fscache tracing debug rfdno=n the file descriptor for reading with trans=fd wfdno=n the file descriptor for writing with trans=fd maxdata=n the number of bytes to use for 9p packet payload (msize) port=n port to connect to on the remote server noextend force legacy mode (no 9p2000.u or 9p2000.L semantics) version=name Select 9P protocol version. Valid options are: 9p2000 - Legacy mode (same as noextend) 9p2000.u - Use 9P2000.u protocol 9p2000.L - Use 9P2000.L protocol dfltuid attempt to mount as a particular uid dfltgid attempt to mount with a particular gid afid security channel - used by Plan 9 authentication protocols nodevmap do not map special files - represent them as normal files. This can be used to share devices/named pipes/sockets between hosts. This functionality will be expanded in later versions. access there are three access modes. user = if a user tries to access a file on v9fs filesystem for the first time, v9fs sends an attach command (Tattach) for that user. This is the default mode. = allows only user with uid= to access the files on the mounted filesystem any = v9fs does single attach and performs all operations as one user cachetag cache tag to use the specified persistent cache. cache tags for existing cache sessions can be listed at /sys/fs/9p/caches. (applies only to cache=fscache) RESOURCES ========= Our current recommendation is to use Inferno (http://www.vitanuova.com/nferno/index.html) as the 9p server. You can start a 9p server under Inferno by issuing the following command: ; styxlisten -A tcp!*!564 export '#U*' The -A specifies an unauthenticated export. The 564 is the port # (you may have to choose a higher port number if running as a normal user). The '#U*' specifies exporting the root of the Linux name space. You may specify a subset of the namespace by extending the path: '#U*'/tmp would just export /tmp. For more information, see the Inferno manual pages covering styxlisten and export. A Linux version of the 9p server is now maintained under the npfs project on sourceforge (http://sourceforge.net/projects/npfs). The currently maintained version is the single-threaded version of the server (named spfs) available from the same SVN repository. There are user and developer mailing lists available through the v9fs project on sourceforge (http://sourceforge.net/projects/v9fs). A stand-alone version of the module (which should build for any 2.6 kernel) is available via (http://github.com/ericvh/9p-sac/tree/master) News and other information is maintained on SWiK (http://swik.net/v9fs) and the Wiki (http://sf.net/apps/mediawiki/v9fs/index.php). Bug reports may be issued through the kernel.org bugzilla (http://bugzilla.kernel.org) For more information on the Plan 9 Operating System check out http://plan9.bell-labs.com/plan9 For information on Plan 9 from User Space (Plan 9 applications and libraries ported to Linux/BSD/OSX/etc) check out http://swtch.com/plan9 STATUS ====== The 2.6 kernel support is working on PPC and x86. PLEASE USE THE KERNEL BUGZILLA TO REPORT PROBLEMS. (http://bugzilla.kernel.org)