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