From ee443996a35c1e04f210cafd43d5a98d41e46085 Mon Sep 17 00:00:00 2001 From: Eric Van Hensbergen Date: Wed, 5 Mar 2008 07:08:09 -0600 Subject: 9p: Documentation updates The kernel-doc comments of much of the 9p system have been in disarray since reorganization. This patch fixes those problems, adds additional documentation and a template book which collects the 9p information. Signed-off-by: Eric Van Hensbergen --- include/net/9p/9p.h | 239 +++++++++++++++++++++++++++++++++++++++------ include/net/9p/client.h | 35 +++++++ include/net/9p/transport.h | 43 ++++++++ 3 files changed, 287 insertions(+), 30 deletions(-) (limited to 'include/net/9p') diff --git a/include/net/9p/9p.h b/include/net/9p/9p.h index 585eb44..7bfb2f2 100644 --- a/include/net/9p/9p.h +++ b/include/net/9p/9p.h @@ -29,14 +29,31 @@ #ifdef CONFIG_NET_9P_DEBUG -#define P9_DEBUG_ERROR (1<<0) -#define P9_DEBUG_9P (1<<2) -#define P9_DEBUG_VFS (1<<3) -#define P9_DEBUG_CONV (1<<4) -#define P9_DEBUG_MUX (1<<5) -#define P9_DEBUG_TRANS (1<<6) -#define P9_DEBUG_SLABS (1<<7) -#define P9_DEBUG_FCALL (1<<8) +/** + * 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 + * + * 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), +}; extern unsigned int p9_debug_level; @@ -62,9 +79,47 @@ do { \ format , __FUNCTION__, 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 + */ -/* Message Types */ -enum { +enum p9_msg_t { P9_TVERSION = 100, P9_RVERSION, P9_TAUTH = 102, @@ -95,30 +150,71 @@ enum { P9_RWSTAT, }; -/* open modes */ -enum { +/** + * 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_OEXCL = 0x04, P9_OTRUNC = 0x10, P9_OREXEC = 0x20, P9_ORCLOSE = 0x40, P9_OAPPEND = 0x80, -}; - -/* permissions */ -enum { + 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, - /* 9P2000.u extensions */ P9_DMDEVICE = 0x00800000, P9_DMNAMEDPIPE = 0x00200000, P9_DMSOCKET = 0x00100000, @@ -127,8 +223,26 @@ enum { P9_DMSETVTX = 0x00010000, }; -/* qid.types */ -enum { +/** + * 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, @@ -140,6 +254,7 @@ enum { P9_QTFILE = 0x00, }; +/* 9P Magic Numbers */ #define P9_NOTAG (u16)(~0) #define P9_NOFID (u32)(~0) #define P9_MAXWELEM 16 @@ -147,19 +262,69 @@ enum { /* 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; }; -/* qids are the unique ID for a file (like an inode */ +/** + * 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; }; -/* Plan 9 file metadata (stat) structure */ +/** + * 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_stat { u16 size; u16 type; @@ -179,10 +344,14 @@ struct p9_stat { u32 n_muid; /* 9p2000.u extensions */ }; -/* file metadata (stat) structure used to create Twstat message - The is similar to p9_stat, but the strings don't point to - the same memory block and should be freed separately -*/ +/* + * file metadata (stat) structure used to create Twstat message + * The is identical to &p9_stat, but the strings don't point to + * the same memory block and should be freed separately + * + * See Also: http://plan9.bell-labs.com/magic/man2html/2/stat + */ + struct p9_wstat { u16 size; u16 type; @@ -335,10 +504,20 @@ struct p9_twstat { struct p9_rwstat { }; -/* - * fcall is the primary packet structure - * - */ +/** + * 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 + * @sdata: payload + * @params: per-operation parameters + * + * &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; diff --git a/include/net/9p/client.h b/include/net/9p/client.h index e52f93d..c936dd1 100644 --- a/include/net/9p/client.h +++ b/include/net/9p/client.h @@ -26,6 +26,23 @@ #ifndef NET_9P_CLIENT_H #define NET_9P_CLIENT_H +/** + * struct p9_client - per client instance state + * @lock: protect @fidlist + * @msize: maximum data size negotiated by protocol + * @dotu: extension flags negotiated by protocol + * @trans_mod: module API instantiated with this client + * @trans: tranport instance state and API + * @conn: connection state information used by trans_fd + * @fidpool: fid handle accounting for session + * @fidlist: List of active fid handles + * + * The client structure is used to keep track of various per-client + * state that has been instantiated. + * + * Bugs: duplicated data and potentially unnecessary elements. + */ + struct p9_client { spinlock_t lock; /* protect client structure */ int msize; @@ -38,6 +55,24 @@ struct p9_client { struct list_head fidlist; }; +/** + * struct p9_fid - file system entity handle + * @clnt: back pointer to instantiating &p9_client + * @fid: numeric identifier for this handle + * @mode: current mode of this fid (enum?) + * @qid: the &p9_qid server identifier this handle points to + * @iounit: the server reported maximum transaction size for this file + * @uid: the numeric uid of the local user who owns this handle + * @aux: transport specific information (unused?) + * @rdir_fpos: tracks offset of file position when reading directory contents + * @rdir_pos: (unused?) + * @rdir_fcall: holds response of last directory read request + * @flist: per-client-instance fid tracking + * @dlist: per-dentry fid tracking + * + * TODO: This needs lots of explanation. + */ + struct p9_fid { struct p9_client *clnt; u32 fid; diff --git a/include/net/9p/transport.h b/include/net/9p/transport.h index d2209ae..240e0de 100644 --- a/include/net/9p/transport.h +++ b/include/net/9p/transport.h @@ -26,12 +26,40 @@ #ifndef NET_9P_TRANSPORT_H #define NET_9P_TRANSPORT_H +/** + * enum p9_trans_status - different states of underlying transports + * @Connected: transport is connected and healthy + * @Disconnected: transport has been disconnected + * @Hung: transport is connected by wedged + * + * This enumeration details the various states a transport + * instatiation can be in. + */ + enum p9_trans_status { Connected, Disconnected, Hung, }; +/** + * struct p9_trans - per-transport state and API + * @status: transport &p9_trans_status + * @msize: negotiated maximum packet size (duplicate from client) + * @extended: negotiated protocol extensions (duplicate from client) + * @priv: transport private data + * @close: member function to disconnect and close the transport + * @rpc: member function to issue a request to the transport + * + * This is the basic API for a transport instance. It is used as + * a handle by the client to issue requests. This interface is currently + * in flux during reorganization. + * + * Bugs: there is lots of duplicated data here and its not clear that + * the member functions need to be per-instance versus per transport + * module. + */ + struct p9_trans { enum p9_trans_status status; int msize; @@ -42,6 +70,21 @@ struct p9_trans { struct p9_fcall **rc); }; +/** + * struct p9_trans_module - transport module interface + * @list: used to maintain a list of currently available transports + * @name: the human-readable name of the transport + * @maxsize: transport provided maximum packet size + * @def: set if this transport should be considered the default + * @create: member function to create a new connection on this transport + * + * This is the basic API for a transport module which is registered by the + * transport module with the 9P core network module and used by the client + * to instantiate a new connection on a transport. + * + * Bugs: the transport module list isn't protected. + */ + struct p9_trans_module { struct list_head list; char *name; /* name of transport */ -- cgit v1.1