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   1 /*
   2  *  linux/fs/9p/v9fs.c
   3  *
   4  *  This file contains functions assisting in mapping VFS to 9P2000
   5  *
   6  *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
   7  *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
   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 #include <linux/module.h>
  27 #include <linux/errno.h>
  28 #include <linux/fs.h>
  29 #include <linux/sched.h>
  30 #include <linux/parser.h>
  31 #include <linux/idr.h>
  32 #include <net/9p/9p.h>
  33 #include <net/9p/transport.h>
  34 #include <net/9p/conn.h>
  35 #include <net/9p/client.h>
  36 #include "v9fs.h"
  37 #include "v9fs_vfs.h"
  38
  39 /*
  40  * Dynamic Transport Registration Routines
  41  *
  42  */
  43
  44 static LIST_HEAD(v9fs_trans_list);
  45 static struct p9_trans_module *v9fs_default_trans;
  46
  47 /**
  48  * v9fs_register_trans - register a new transport with 9p
  49  * @m - structure describing the transport module and entry points
  50  *
  51  */
  52 void v9fs_register_trans(struct p9_trans_module *m)
  53 {
  54         list_add_tail(&m->list, &v9fs_trans_list);
  55         if (m->def)
  56                 v9fs_default_trans = m;
  57 }
  58 EXPORT_SYMBOL(v9fs_register_trans);
  59
  60 /**
  61  * v9fs_match_trans - match transport versus registered transports
  62  * @arg: string identifying transport
  63  *
  64  */
  65 static struct p9_trans_module *v9fs_match_trans(const substring_t *name)
  66 {
  67         struct list_head *p;
  68         struct p9_trans_module *t = NULL;
  69
  70         list_for_each(p, &v9fs_trans_list) {
  71                 t = list_entry(p, struct p9_trans_module, list);
  72                 if (strncmp(t->name, name->from, name->to-name->from) == 0) {
  73                         P9_DPRINTK(P9_DEBUG_TRANS, "trans=%s\n", t->name);
  74                         break;
  75                 }
  76         }
  77         return t;
  78 }
  79
  80 /*
  81   * Option Parsing (code inspired by NFS code)
  82   *  NOTE: each transport will parse its own options
  83   */
  84
  85 enum {
  86         /* Options that take integer arguments */
  87         Opt_debug, Opt_msize, Opt_dfltuid, Opt_dfltgid, Opt_afid,
  88         /* String options */
  89         Opt_uname, Opt_remotename, Opt_trans,
  90         /* Options that take no arguments */
  91         Opt_legacy, Opt_nodevmap,
  92         /* Cache options */
  93         Opt_cache_loose,
  94         /* Error token */
  95         Opt_err
  96 };
  97
  98 static match_table_t tokens = {
  99         {Opt_debug, "debug=%x"},
 100         {Opt_msize, "msize=%u"},
 101         {Opt_dfltuid, "dfltuid=%u"},
 102         {Opt_dfltgid, "dfltgid=%u"},
 103         {Opt_afid, "afid=%u"},
 104         {Opt_uname, "uname=%s"},
 105         {Opt_remotename, "aname=%s"},
 106         {Opt_trans, "trans=%s"},
 107         {Opt_legacy, "noextend"},
 108         {Opt_nodevmap, "nodevmap"},
 109         {Opt_cache_loose, "cache=loose"},
 110         {Opt_cache_loose, "loose"},
 111         {Opt_err, NULL}
 112 };
 113
 114 /**
 115  * v9fs_parse_options - parse mount options into session structure
 116  * @options: options string passed from mount
 117  * @v9ses: existing v9fs session information
 118  *
 119  */
 120
 121 static void v9fs_parse_options(struct v9fs_session_info *v9ses)
 122 {
 123         char *options = v9ses->options;
 124         substring_t args[MAX_OPT_ARGS];
 125         char *p;
 126         int option;
 127         int ret;
 128
 129         /* setup defaults */
 130         v9ses->maxdata = 8192;
 131         v9ses->flags = V9FS_EXTENDED;
 132         v9ses->afid = ~0;
 133         v9ses->debug = 0;
 134         v9ses->cache = 0;
 135         v9ses->trans = v9fs_default_trans;
 136
 137         if (!options)
 138                 return;
 139
 140         while ((p = strsep(&options, ",")) != NULL) {
 141                 int token;
 142                 if (!*p)
 143                         continue;
 144                 token = match_token(p, tokens, args);
 145                 if (token < Opt_uname) {
 146                         if ((ret = match_int(&args[0], &option)) < 0) {
 147                                 P9_DPRINTK(P9_DEBUG_ERROR,
 148                                         "integer field, but no integer?\n");
 149                                 continue;
 150                         }
 151                 }
 152                 switch (token) {
 153                 case Opt_debug:
 154                         v9ses->debug = option;
 155 #ifdef CONFIG_NET_9P_DEBUG
 156                         p9_debug_level = option;
 157 #endif
 158                         break;
 159                 case Opt_msize:
 160                         v9ses->maxdata = option;
 161                         break;
 162                 case Opt_dfltuid:
 163                         v9ses->dfltuid = option;
 164                         break;
 165                 case Opt_dfltgid:
 166                         v9ses->dfltgid = option;
 167                         break;
 168                 case Opt_afid:
 169                         v9ses->afid = option;
 170                         break;
 171                 case Opt_trans:
 172                         v9ses->trans = v9fs_match_trans(&args[0]);
 173                         break;
 174                 case Opt_uname:
 175                         match_strcpy(v9ses->name, &args[0]);
 176                         break;
 177                 case Opt_remotename:
 178                         match_strcpy(v9ses->remotename, &args[0]);
 179                         break;
 180                 case Opt_legacy:
 181                         v9ses->flags &= ~V9FS_EXTENDED;
 182                         break;
 183                 case Opt_nodevmap:
 184                         v9ses->nodev = 1;
 185                         break;
 186                 case Opt_cache_loose:
 187                         v9ses->cache = CACHE_LOOSE;
 188                         break;
 189                 default:
 190                         continue;
 191                 }
 192         }
 193 }
 194
 195 /**
 196  * v9fs_session_init - initialize session
 197  * @v9ses: session information structure
 198  * @dev_name: device being mounted
 199  * @data: options
 200  *
 201  */
 202
 203 struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
 204                   const char *dev_name, char *data)
 205 {
 206         int retval = -EINVAL;
 207         struct p9_trans *trans = NULL;
 208         struct p9_fid *fid;
 209
 210         v9ses->name = __getname();
 211         if (!v9ses->name)
 212                 return ERR_PTR(-ENOMEM);
 213
 214         v9ses->remotename = __getname();
 215         if (!v9ses->remotename) {
 216                 __putname(v9ses->name);
 217                 return ERR_PTR(-ENOMEM);
 218         }
 219
 220         strcpy(v9ses->name, V9FS_DEFUSER);
 221         strcpy(v9ses->remotename, V9FS_DEFANAME);
 222         v9ses->dfltuid = V9FS_DEFUID;
 223         v9ses->dfltgid = V9FS_DEFGID;
 224
 225         v9ses->options = kstrdup(data, GFP_KERNEL);
 226         v9fs_parse_options(v9ses);
 227
 228         if ((v9ses->trans == NULL) && !list_empty(&v9fs_trans_list))
 229                 v9ses->trans = list_first_entry(&v9fs_trans_list,
 230                  struct p9_trans_module, list);
 231
 232         if (v9ses->trans == NULL) {
 233                 retval = -EPROTONOSUPPORT;
 234                 P9_DPRINTK(P9_DEBUG_ERROR,
 235                                 "No transport defined or default transport\n");
 236                 goto error;
 237         }
 238
 239         trans = v9ses->trans->create(dev_name, v9ses->options);
 240         if (IS_ERR(trans)) {
 241                 retval = PTR_ERR(trans);
 242                 trans = NULL;
 243                 goto error;
 244         }
 245         if ((v9ses->maxdata+P9_IOHDRSZ) > v9ses->trans->maxsize)
 246                 v9ses->maxdata = v9ses->trans->maxsize-P9_IOHDRSZ;
 247
 248         v9ses->clnt = p9_client_create(trans, v9ses->maxdata+P9_IOHDRSZ,
 249                 v9fs_extended(v9ses));
 250
 251         if (IS_ERR(v9ses->clnt)) {
 252                 retval = PTR_ERR(v9ses->clnt);
 253                 v9ses->clnt = NULL;
 254                 P9_DPRINTK(P9_DEBUG_ERROR, "problem initializing 9p client\n");
 255                 goto error;
 256         }
 257
 258         fid = p9_client_attach(v9ses->clnt, NULL, v9ses->name,
 259                                                         v9ses->remotename);
 260         if (IS_ERR(fid)) {
 261                 retval = PTR_ERR(fid);
 262                 fid = NULL;
 263                 P9_DPRINTK(P9_DEBUG_ERROR, "cannot attach\n");
 264                 goto error;
 265         }
 266
 267         return fid;
 268
 269 error:
 270         v9fs_session_close(v9ses);
 271         return ERR_PTR(retval);
 272 }
 273
 274 /**
 275  * v9fs_session_close - shutdown a session
 276  * @v9ses: session information structure
 277  *
 278  */
 279
 280 void v9fs_session_close(struct v9fs_session_info *v9ses)
 281 {
 282         if (v9ses->clnt) {
 283                 p9_client_destroy(v9ses->clnt);
 284                 v9ses->clnt = NULL;
 285         }
 286
 287         __putname(v9ses->name);
 288         __putname(v9ses->remotename);
 289         kfree(v9ses->options);
 290 }
 291
 292 /**
 293  * v9fs_session_cancel - mark transport as disconnected
 294  *      and cancel all pending requests.
 295  */
 296 void v9fs_session_cancel(struct v9fs_session_info *v9ses) {
 297         P9_DPRINTK(P9_DEBUG_ERROR, "cancel session %p\n", v9ses);
 298         p9_client_disconnect(v9ses->clnt);
 299 }
 300
 301 extern int v9fs_error_init(void);
 302
 303 /**
 304  * v9fs_init - Initialize module
 305  *
 306  */
 307
 308 static int __init init_v9fs(void)
 309 {
 310         printk(KERN_INFO "Installing v9fs 9p2000 file system support\n");
 311         /* TODO: Setup list of registered trasnport modules */
 312         return register_filesystem(&v9fs_fs_type);
 313 }
 314
 315 /**
 316  * v9fs_init - shutdown module
 317  *
 318  */
 319
 320 static void __exit exit_v9fs(void)
 321 {
 322         unregister_filesystem(&v9fs_fs_type);
 323 }
 324
 325 module_init(init_v9fs)
 326 module_exit(exit_v9fs)
 327
 328 MODULE_AUTHOR("Latchesar Ionkov <lucho@ionkov.net>");
 329 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
 330 MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
 331 MODULE_LICENSE("GPL");