linux/include/net/9p/9p.h
Abhishek Kulkarni 60e78d2c99 9p: Add fscache support to 9p
This patch adds a persistent, read-only caching facility for
9p clients using the FS-Cache caching backend.

When the fscache facility is enabled, each inode is associated
with a corresponding vcookie which is an index into the FS-Cache
indexing tree. The FS-Cache indexing tree is indexed at 3 levels:
- session object associated with each mount.
- inode/vcookie
- actual data (pages)

A cache tag is chosen randomly for each session. These tags can
be read off /sys/fs/9p/caches and can be passed as a mount-time
parameter to re-attach to the specified caching session.

Signed-off-by: Abhishek Kulkarni <adkulkar@umail.iu.edu>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
2009-09-23 13:03:46 -05:00

527 lines
13 KiB
C

/*
* include/net/9p/9p.h
*
* 9P protocol definitions.
*
* Copyright (C) 2005 by Latchesar Ionkov <lucho@ionkov.net>
* Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
* Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to:
* Free Software Foundation
* 51 Franklin Street, Fifth Floor
* Boston, MA 02111-1301 USA
*
*/
#ifndef NET_9P_H
#define NET_9P_H
/**
* enum p9_debug_flags - bits for mount time debug parameter
* @P9_DEBUG_ERROR: more verbose error messages including original error string
* @P9_DEBUG_9P: 9P protocol tracing
* @P9_DEBUG_VFS: VFS API tracing
* @P9_DEBUG_CONV: protocol conversion tracing
* @P9_DEBUG_MUX: trace management of concurrent transactions
* @P9_DEBUG_TRANS: transport tracing
* @P9_DEBUG_SLABS: memory management tracing
* @P9_DEBUG_FCALL: verbose dump of protocol messages
* @P9_DEBUG_FID: fid allocation/deallocation tracking
* @P9_DEBUG_PKT: packet marshalling/unmarshalling
* @P9_DEBUG_FSC: FS-cache tracing
*
* These flags are passed at mount time to turn on various levels of
* verbosity and tracing which will be output to the system logs.
*/
enum p9_debug_flags {
P9_DEBUG_ERROR = (1<<0),
P9_DEBUG_9P = (1<<2),
P9_DEBUG_VFS = (1<<3),
P9_DEBUG_CONV = (1<<4),
P9_DEBUG_MUX = (1<<5),
P9_DEBUG_TRANS = (1<<6),
P9_DEBUG_SLABS = (1<<7),
P9_DEBUG_FCALL = (1<<8),
P9_DEBUG_FID = (1<<9),
P9_DEBUG_PKT = (1<<10),
P9_DEBUG_FSC = (1<<11),
};
#ifdef CONFIG_NET_9P_DEBUG
extern unsigned int p9_debug_level;
#define P9_DPRINTK(level, format, arg...) \
do { \
if ((p9_debug_level & level) == level) {\
if (level == P9_DEBUG_9P) \
printk(KERN_NOTICE "(%8.8d) " \
format , task_pid_nr(current) , ## arg); \
else \
printk(KERN_NOTICE "-- %s (%d): " \
format , __func__, task_pid_nr(current) , ## arg); \
} \
} while (0)
#else
#define P9_DPRINTK(level, format, arg...) do { } while (0)
#endif
#define P9_EPRINTK(level, format, arg...) \
do { \
printk(level "9p: %s (%d): " \
format , __func__, task_pid_nr(current), ## arg); \
} while (0)
/**
* enum p9_msg_t - 9P message types
* @P9_TVERSION: version handshake request
* @P9_RVERSION: version handshake response
* @P9_TAUTH: request to establish authentication channel
* @P9_RAUTH: response with authentication information
* @P9_TATTACH: establish user access to file service
* @P9_RATTACH: response with top level handle to file hierarchy
* @P9_TERROR: not used
* @P9_RERROR: response for any failed request
* @P9_TFLUSH: request to abort a previous request
* @P9_RFLUSH: response when previous request has been cancelled
* @P9_TWALK: descend a directory hierarchy
* @P9_RWALK: response with new handle for position within hierarchy
* @P9_TOPEN: prepare a handle for I/O on an existing file
* @P9_ROPEN: response with file access information
* @P9_TCREATE: prepare a handle for I/O on a new file
* @P9_RCREATE: response with file access information
* @P9_TREAD: request to transfer data from a file or directory
* @P9_RREAD: response with data requested
* @P9_TWRITE: reuqest to transfer data to a file
* @P9_RWRITE: response with out much data was transfered to file
* @P9_TCLUNK: forget about a handle to an entity within the file system
* @P9_RCLUNK: response when server has forgotten about the handle
* @P9_TREMOVE: request to remove an entity from the hierarchy
* @P9_RREMOVE: response when server has removed the entity
* @P9_TSTAT: request file entity attributes
* @P9_RSTAT: response with file entity attributes
* @P9_TWSTAT: request to update file entity attributes
* @P9_RWSTAT: response when file entity attributes are updated
*
* There are 14 basic operations in 9P2000, paired as
* requests and responses. The one special case is ERROR
* as there is no @P9_TERROR request for clients to transmit to
* the server, but the server may respond to any other request
* with an @P9_RERROR.
*
* See Also: http://plan9.bell-labs.com/sys/man/5/INDEX.html
*/
enum p9_msg_t {
P9_TVERSION = 100,
P9_RVERSION,
P9_TAUTH = 102,
P9_RAUTH,
P9_TATTACH = 104,
P9_RATTACH,
P9_TERROR = 106,
P9_RERROR,
P9_TFLUSH = 108,
P9_RFLUSH,
P9_TWALK = 110,
P9_RWALK,
P9_TOPEN = 112,
P9_ROPEN,
P9_TCREATE = 114,
P9_RCREATE,
P9_TREAD = 116,
P9_RREAD,
P9_TWRITE = 118,
P9_RWRITE,
P9_TCLUNK = 120,
P9_RCLUNK,
P9_TREMOVE = 122,
P9_RREMOVE,
P9_TSTAT = 124,
P9_RSTAT,
P9_TWSTAT = 126,
P9_RWSTAT,
};
/**
* enum p9_open_mode_t - 9P open modes
* @P9_OREAD: open file for reading only
* @P9_OWRITE: open file for writing only
* @P9_ORDWR: open file for reading or writing
* @P9_OEXEC: open file for execution
* @P9_OTRUNC: truncate file to zero-length before opening it
* @P9_OREXEC: close the file when an exec(2) system call is made
* @P9_ORCLOSE: remove the file when the file is closed
* @P9_OAPPEND: open the file and seek to the end
* @P9_OEXCL: only create a file, do not open it
*
* 9P open modes differ slightly from Posix standard modes.
* In particular, there are extra modes which specify different
* semantic behaviors than may be available on standard Posix
* systems. For example, @P9_OREXEC and @P9_ORCLOSE are modes that
* most likely will not be issued from the Linux VFS client, but may
* be supported by servers.
*
* See Also: http://plan9.bell-labs.com/magic/man2html/2/open
*/
enum p9_open_mode_t {
P9_OREAD = 0x00,
P9_OWRITE = 0x01,
P9_ORDWR = 0x02,
P9_OEXEC = 0x03,
P9_OTRUNC = 0x10,
P9_OREXEC = 0x20,
P9_ORCLOSE = 0x40,
P9_OAPPEND = 0x80,
P9_OEXCL = 0x1000,
};
/**
* enum p9_perm_t - 9P permissions
* @P9_DMDIR: mode bite for directories
* @P9_DMAPPEND: mode bit for is append-only
* @P9_DMEXCL: mode bit for excluse use (only one open handle allowed)
* @P9_DMMOUNT: mode bite for mount points
* @P9_DMAUTH: mode bit for authentication file
* @P9_DMTMP: mode bit for non-backed-up files
* @P9_DMSYMLINK: mode bit for symbolic links (9P2000.u)
* @P9_DMLINK: mode bit for hard-link (9P2000.u)
* @P9_DMDEVICE: mode bit for device files (9P2000.u)
* @P9_DMNAMEDPIPE: mode bit for named pipe (9P2000.u)
* @P9_DMSOCKET: mode bit for socket (9P2000.u)
* @P9_DMSETUID: mode bit for setuid (9P2000.u)
* @P9_DMSETGID: mode bit for setgid (9P2000.u)
* @P9_DMSETVTX: mode bit for sticky bit (9P2000.u)
*
* 9P permissions differ slightly from Posix standard modes.
*
* See Also: http://plan9.bell-labs.com/magic/man2html/2/stat
*/
enum p9_perm_t {
P9_DMDIR = 0x80000000,
P9_DMAPPEND = 0x40000000,
P9_DMEXCL = 0x20000000,
P9_DMMOUNT = 0x10000000,
P9_DMAUTH = 0x08000000,
P9_DMTMP = 0x04000000,
/* 9P2000.u extensions */
P9_DMSYMLINK = 0x02000000,
P9_DMLINK = 0x01000000,
P9_DMDEVICE = 0x00800000,
P9_DMNAMEDPIPE = 0x00200000,
P9_DMSOCKET = 0x00100000,
P9_DMSETUID = 0x00080000,
P9_DMSETGID = 0x00040000,
P9_DMSETVTX = 0x00010000,
};
/**
* enum p9_qid_t - QID types
* @P9_QTDIR: directory
* @P9_QTAPPEND: append-only
* @P9_QTEXCL: excluse use (only one open handle allowed)
* @P9_QTMOUNT: mount points
* @P9_QTAUTH: authentication file
* @P9_QTTMP: non-backed-up files
* @P9_QTSYMLINK: symbolic links (9P2000.u)
* @P9_QTLINK: hard-link (9P2000.u)
* @P9_QTFILE: normal files
*
* QID types are a subset of permissions - they are primarily
* used to differentiate semantics for a file system entity via
* a jump-table. Their value is also the most signifigant 16 bits
* of the permission_t
*
* See Also: http://plan9.bell-labs.com/magic/man2html/2/stat
*/
enum p9_qid_t {
P9_QTDIR = 0x80,
P9_QTAPPEND = 0x40,
P9_QTEXCL = 0x20,
P9_QTMOUNT = 0x10,
P9_QTAUTH = 0x08,
P9_QTTMP = 0x04,
P9_QTSYMLINK = 0x02,
P9_QTLINK = 0x01,
P9_QTFILE = 0x00,
};
/* 9P Magic Numbers */
#define P9_NOTAG (u16)(~0)
#define P9_NOFID (u32)(~0)
#define P9_MAXWELEM 16
/* ample room for Twrite/Rread header */
#define P9_IOHDRSZ 24
/**
* struct p9_str - length prefixed string type
* @len: length of the string
* @str: the string
*
* The protocol uses length prefixed strings for all
* string data, so we replicate that for our internal
* string members.
*/
struct p9_str {
u16 len;
char *str;
};
/**
* struct p9_qid - file system entity information
* @type: 8-bit type &p9_qid_t
* @version: 16-bit monotonically incrementing version number
* @path: 64-bit per-server-unique ID for a file system element
*
* qids are identifiers used by 9P servers to track file system
* entities. The type is used to differentiate semantics for operations
* on the entity (ie. read means something different on a directory than
* on a file). The path provides a server unique index for an entity
* (roughly analogous to an inode number), while the version is updated
* every time a file is modified and can be used to maintain cache
* coherency between clients and serves.
* Servers will often differentiate purely synthetic entities by setting
* their version to 0, signaling that they should never be cached and
* should be accessed synchronously.
*
* See Also://plan9.bell-labs.com/magic/man2html/2/stat
*/
struct p9_qid {
u8 type;
u32 version;
u64 path;
};
/**
* struct p9_stat - file system metadata information
* @size: length prefix for this stat structure instance
* @type: the type of the server (equivilent to a major number)
* @dev: the sub-type of the server (equivilent to a minor number)
* @qid: unique id from the server of type &p9_qid
* @mode: Plan 9 format permissions of type &p9_perm_t
* @atime: Last access/read time
* @mtime: Last modify/write time
* @length: file length
* @name: last element of path (aka filename) in type &p9_str
* @uid: owner name in type &p9_str
* @gid: group owner in type &p9_str
* @muid: last modifier in type &p9_str
* @extension: area used to encode extended UNIX support in type &p9_str
* @n_uid: numeric user id of owner (part of 9p2000.u extension)
* @n_gid: numeric group id (part of 9p2000.u extension)
* @n_muid: numeric user id of laster modifier (part of 9p2000.u extension)
*
* See Also: http://plan9.bell-labs.com/magic/man2html/2/stat
*/
struct p9_wstat {
u16 size;
u16 type;
u32 dev;
struct p9_qid qid;
u32 mode;
u32 atime;
u32 mtime;
u64 length;
char *name;
char *uid;
char *gid;
char *muid;
char *extension; /* 9p2000.u extensions */
u32 n_uid; /* 9p2000.u extensions */
u32 n_gid; /* 9p2000.u extensions */
u32 n_muid; /* 9p2000.u extensions */
};
/* Structures for Protocol Operations */
struct p9_tversion {
u32 msize;
struct p9_str version;
};
struct p9_rversion {
u32 msize;
struct p9_str version;
};
struct p9_tauth {
u32 afid;
struct p9_str uname;
struct p9_str aname;
u32 n_uname; /* 9P2000.u extensions */
};
struct p9_rauth {
struct p9_qid qid;
};
struct p9_rerror {
struct p9_str error;
u32 errno; /* 9p2000.u extension */
};
struct p9_tflush {
u16 oldtag;
};
struct p9_rflush {
};
struct p9_tattach {
u32 fid;
u32 afid;
struct p9_str uname;
struct p9_str aname;
u32 n_uname; /* 9P2000.u extensions */
};
struct p9_rattach {
struct p9_qid qid;
};
struct p9_twalk {
u32 fid;
u32 newfid;
u16 nwname;
struct p9_str wnames[16];
};
struct p9_rwalk {
u16 nwqid;
struct p9_qid wqids[16];
};
struct p9_topen {
u32 fid;
u8 mode;
};
struct p9_ropen {
struct p9_qid qid;
u32 iounit;
};
struct p9_tcreate {
u32 fid;
struct p9_str name;
u32 perm;
u8 mode;
struct p9_str extension;
};
struct p9_rcreate {
struct p9_qid qid;
u32 iounit;
};
struct p9_tread {
u32 fid;
u64 offset;
u32 count;
};
struct p9_rread {
u32 count;
u8 *data;
};
struct p9_twrite {
u32 fid;
u64 offset;
u32 count;
u8 *data;
};
struct p9_rwrite {
u32 count;
};
struct p9_tclunk {
u32 fid;
};
struct p9_rclunk {
};
struct p9_tremove {
u32 fid;
};
struct p9_rremove {
};
struct p9_tstat {
u32 fid;
};
struct p9_rstat {
struct p9_wstat stat;
};
struct p9_twstat {
u32 fid;
struct p9_wstat stat;
};
struct p9_rwstat {
};
/**
* struct p9_fcall - primary packet structure
* @size: prefixed length of the structure
* @id: protocol operating identifier of type &p9_msg_t
* @tag: transaction id of the request
* @offset: used by marshalling routines to track currentposition in buffer
* @capacity: used by marshalling routines to track total capacity
* @sdata: payload
*
* &p9_fcall represents the structure for all 9P RPC
* transactions. Requests are packaged into fcalls, and reponses
* must be extracted from them.
*
* See Also: http://plan9.bell-labs.com/magic/man2html/2/fcall
*/
struct p9_fcall {
u32 size;
u8 id;
u16 tag;
size_t offset;
size_t capacity;
uint8_t *sdata;
};
struct p9_idpool;
int p9_errstr2errno(char *errstr, int len);
struct p9_idpool *p9_idpool_create(void);
void p9_idpool_destroy(struct p9_idpool *);
int p9_idpool_get(struct p9_idpool *p);
void p9_idpool_put(int id, struct p9_idpool *p);
int p9_idpool_check(int id, struct p9_idpool *p);
int p9_error_init(void);
int p9_errstr2errno(char *, int);
int p9_trans_fd_init(void);
void p9_trans_fd_exit(void);
#endif /* NET_9P_H */