linux/include/net/9p/client.h
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   1/*
   2 * include/net/9p/client.h
   3 *
   4 * 9P Client Definitions
   5 *
   6 *  Copyright (C) 2008 by Eric Van Hensbergen <ericvh@gmail.com>
   7 *  Copyright (C) 2007 by Latchesar Ionkov <lucho@ionkov.net>
   8 *
   9 *  This program is free software; you can redistribute it and/or modify
  10 *  it under the terms of the GNU General Public License version 2
  11 *  as published by the Free Software Foundation.
  12 *
  13 *  This program is distributed in the hope that it will be useful,
  14 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 *  GNU General Public License for more details.
  17 *
  18 *  You should have received a copy of the GNU General Public License
  19 *  along with this program; if not, write to:
  20 *  Free Software Foundation
  21 *  51 Franklin Street, Fifth Floor
  22 *  Boston, MA  02111-1301  USA
  23 *
  24 */
  25
  26#ifndef NET_9P_CLIENT_H
  27#define NET_9P_CLIENT_H
  28
  29#include <linux/utsname.h>
  30
  31/* Number of requests per row */
  32#define P9_ROW_MAXTAG 255
  33
  34/** enum p9_proto_versions - 9P protocol versions
  35 * @p9_proto_legacy: 9P Legacy mode, pre-9P2000.u
  36 * @p9_proto_2000u: 9P2000.u extension
  37 * @p9_proto_2000L: 9P2000.L extension
  38 */
  39
  40enum p9_proto_versions{
  41        p9_proto_legacy,
  42        p9_proto_2000u,
  43        p9_proto_2000L,
  44};
  45
  46
  47/**
  48 * enum p9_trans_status - different states of underlying transports
  49 * @Connected: transport is connected and healthy
  50 * @Disconnected: transport has been disconnected
  51 * @Hung: transport is connected by wedged
  52 *
  53 * This enumeration details the various states a transport
  54 * instatiation can be in.
  55 */
  56
  57enum p9_trans_status {
  58        Connected,
  59        BeginDisconnect,
  60        Disconnected,
  61        Hung,
  62};
  63
  64/**
  65 * enum p9_req_status_t - status of a request
  66 * @REQ_STATUS_IDLE: request slot unused
  67 * @REQ_STATUS_ALLOC: request has been allocated but not sent
  68 * @REQ_STATUS_UNSENT: request waiting to be sent
  69 * @REQ_STATUS_SENT: request sent to server
  70 * @REQ_STATUS_RCVD: response received from server
  71 * @REQ_STATUS_FLSHD: request has been flushed
  72 * @REQ_STATUS_ERROR: request encountered an error on the client side
  73 *
  74 * The @REQ_STATUS_IDLE state is used to mark a request slot as unused
  75 * but use is actually tracked by the idpool structure which handles tag
  76 * id allocation.
  77 *
  78 */
  79
  80enum p9_req_status_t {
  81        REQ_STATUS_IDLE,
  82        REQ_STATUS_ALLOC,
  83        REQ_STATUS_UNSENT,
  84        REQ_STATUS_SENT,
  85        REQ_STATUS_RCVD,
  86        REQ_STATUS_FLSHD,
  87        REQ_STATUS_ERROR,
  88};
  89
  90/**
  91 * struct p9_req_t - request slots
  92 * @status: status of this request slot
  93 * @t_err: transport error
  94 * @flush_tag: tag of request being flushed (for flush requests)
  95 * @wq: wait_queue for the client to block on for this request
  96 * @tc: the request fcall structure
  97 * @rc: the response fcall structure
  98 * @aux: transport specific data (provided for trans_fd migration)
  99 * @req_list: link for higher level objects to chain requests
 100 *
 101 * Transport use an array to track outstanding requests
 102 * instead of a list.  While this may incurr overhead during initial
 103 * allocation or expansion, it makes request lookup much easier as the
 104 * tag id is a index into an array.  (We use tag+1 so that we can accommodate
 105 * the -1 tag for the T_VERSION request).
 106 * This also has the nice effect of only having to allocate wait_queues
 107 * once, instead of constantly allocating and freeing them.  Its possible
 108 * other resources could benefit from this scheme as well.
 109 *
 110 */
 111
 112struct p9_req_t {
 113        int status;
 114        int t_err;
 115        wait_queue_head_t *wq;
 116        struct p9_fcall *tc;
 117        struct p9_fcall *rc;
 118        void *aux;
 119
 120        struct list_head req_list;
 121};
 122
 123/**
 124 * struct p9_client - per client instance state
 125 * @lock: protect @fidlist
 126 * @msize: maximum data size negotiated by protocol
 127 * @dotu: extension flags negotiated by protocol
 128 * @proto_version: 9P protocol version to use
 129 * @trans_mod: module API instantiated with this client
 130 * @trans: tranport instance state and API
 131 * @fidpool: fid handle accounting for session
 132 * @fidlist: List of active fid handles
 133 * @tagpool - transaction id accounting for session
 134 * @reqs - 2D array of requests
 135 * @max_tag - current maximum tag id allocated
 136 * @name - node name used as client id
 137 *
 138 * The client structure is used to keep track of various per-client
 139 * state that has been instantiated.
 140 * In order to minimize per-transaction overhead we use a
 141 * simple array to lookup requests instead of a hash table
 142 * or linked list.  In order to support larger number of
 143 * transactions, we make this a 2D array, allocating new rows
 144 * when we need to grow the total number of the transactions.
 145 *
 146 * Each row is 256 requests and we'll support up to 256 rows for
 147 * a total of 64k concurrent requests per session.
 148 *
 149 * Bugs: duplicated data and potentially unnecessary elements.
 150 */
 151
 152struct p9_client {
 153        spinlock_t lock; /* protect client structure */
 154        unsigned int msize;
 155        unsigned char proto_version;
 156        struct p9_trans_module *trans_mod;
 157        enum p9_trans_status status;
 158        void *trans;
 159
 160        union {
 161                struct {
 162                        int rfd;
 163                        int wfd;
 164                } fd;
 165                struct {
 166                        u16 port;
 167                        bool privport;
 168
 169                } tcp;
 170        } trans_opts;
 171
 172        struct p9_idpool *fidpool;
 173        struct list_head fidlist;
 174
 175        struct p9_idpool *tagpool;
 176        struct p9_req_t *reqs[P9_ROW_MAXTAG];
 177        int max_tag;
 178
 179        char name[__NEW_UTS_LEN + 1];
 180};
 181
 182/**
 183 * struct p9_fid - file system entity handle
 184 * @clnt: back pointer to instantiating &p9_client
 185 * @fid: numeric identifier for this handle
 186 * @mode: current mode of this fid (enum?)
 187 * @qid: the &p9_qid server identifier this handle points to
 188 * @iounit: the server reported maximum transaction size for this file
 189 * @uid: the numeric uid of the local user who owns this handle
 190 * @rdir: readdir accounting structure (allocated on demand)
 191 * @flist: per-client-instance fid tracking
 192 * @dlist: per-dentry fid tracking
 193 *
 194 * TODO: This needs lots of explanation.
 195 */
 196
 197struct p9_fid {
 198        struct p9_client *clnt;
 199        u32 fid;
 200        int mode;
 201        struct p9_qid qid;
 202        u32 iounit;
 203        kuid_t uid;
 204
 205        void *rdir;
 206
 207        struct list_head flist;
 208        struct hlist_node dlist;        /* list of all fids attached to a dentry */
 209};
 210
 211/**
 212 * struct p9_dirent - directory entry structure
 213 * @qid: The p9 server qid for this dirent
 214 * @d_off: offset to the next dirent
 215 * @d_type: type of file
 216 * @d_name: file name
 217 */
 218
 219struct p9_dirent {
 220        struct p9_qid qid;
 221        u64 d_off;
 222        unsigned char d_type;
 223        char d_name[256];
 224};
 225
 226struct iov_iter;
 227
 228int p9_show_client_options(struct seq_file *m, struct p9_client *clnt);
 229int p9_client_statfs(struct p9_fid *fid, struct p9_rstatfs *sb);
 230int p9_client_rename(struct p9_fid *fid, struct p9_fid *newdirfid,
 231                     const char *name);
 232int p9_client_renameat(struct p9_fid *olddirfid, const char *old_name,
 233                       struct p9_fid *newdirfid, const char *new_name);
 234struct p9_client *p9_client_create(const char *dev_name, char *options);
 235void p9_client_destroy(struct p9_client *clnt);
 236void p9_client_disconnect(struct p9_client *clnt);
 237void p9_client_begin_disconnect(struct p9_client *clnt);
 238struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid,
 239                                const char *uname, kuid_t n_uname, const char *aname);
 240struct p9_fid *p9_client_walk(struct p9_fid *oldfid, uint16_t nwname,
 241                const unsigned char * const *wnames, int clone);
 242int p9_client_open(struct p9_fid *fid, int mode);
 243int p9_client_fcreate(struct p9_fid *fid, const char *name, u32 perm, int mode,
 244                                                        char *extension);
 245int p9_client_link(struct p9_fid *fid, struct p9_fid *oldfid, const char *newname);
 246int p9_client_symlink(struct p9_fid *fid, const char *name, const char *symname,
 247                kgid_t gid, struct p9_qid *qid);
 248int p9_client_create_dotl(struct p9_fid *ofid, const char *name, u32 flags, u32 mode,
 249                kgid_t gid, struct p9_qid *qid);
 250int p9_client_clunk(struct p9_fid *fid);
 251int p9_client_fsync(struct p9_fid *fid, int datasync);
 252int p9_client_remove(struct p9_fid *fid);
 253int p9_client_unlinkat(struct p9_fid *dfid, const char *name, int flags);
 254int p9_client_read(struct p9_fid *fid, u64 offset, struct iov_iter *to, int *err);
 255int p9_client_write(struct p9_fid *fid, u64 offset, struct iov_iter *from, int *err);
 256int p9_client_readdir(struct p9_fid *fid, char *data, u32 count, u64 offset);
 257int p9dirent_read(struct p9_client *clnt, char *buf, int len,
 258                  struct p9_dirent *dirent);
 259struct p9_wstat *p9_client_stat(struct p9_fid *fid);
 260int p9_client_wstat(struct p9_fid *fid, struct p9_wstat *wst);
 261int p9_client_setattr(struct p9_fid *fid, struct p9_iattr_dotl *attr);
 262
 263struct p9_stat_dotl *p9_client_getattr_dotl(struct p9_fid *fid,
 264                                                        u64 request_mask);
 265
 266int p9_client_mknod_dotl(struct p9_fid *oldfid, const char *name, int mode,
 267                        dev_t rdev, kgid_t gid, struct p9_qid *);
 268int p9_client_mkdir_dotl(struct p9_fid *fid, const char *name, int mode,
 269                                kgid_t gid, struct p9_qid *);
 270int p9_client_lock_dotl(struct p9_fid *fid, struct p9_flock *flock, u8 *status);
 271int p9_client_getlock_dotl(struct p9_fid *fid, struct p9_getlock *fl);
 272struct p9_req_t *p9_tag_lookup(struct p9_client *, u16);
 273void p9_client_cb(struct p9_client *c, struct p9_req_t *req, int status);
 274
 275int p9_parse_header(struct p9_fcall *, int32_t *, int8_t *, int16_t *, int);
 276int p9stat_read(struct p9_client *, char *, int, struct p9_wstat *);
 277void p9stat_free(struct p9_wstat *);
 278
 279int p9_is_proto_dotu(struct p9_client *clnt);
 280int p9_is_proto_dotl(struct p9_client *clnt);
 281struct p9_fid *p9_client_xattrwalk(struct p9_fid *, const char *, u64 *);
 282int p9_client_xattrcreate(struct p9_fid *, const char *, u64, int);
 283int p9_client_readlink(struct p9_fid *fid, char **target);
 284
 285#endif /* NET_9P_CLIENT_H */
 286