fs/9p/v9fs.c

   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 as published by
  11  *  the Free Software Foundation; either version 2 of the License, or
  12  *  (at your option) any later version.
  13  *
  14  *  This program is distributed in the hope that it will be useful,
  15  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  *  GNU General Public License for more details.
  18  *
  19  *  You should have received a copy of the GNU General Public License
  20  *  along with this program; if not, write to:
  21  *  Free Software Foundation
  22  *  51 Franklin Street, Fifth Floor
  23  *  Boston, MA  02111-1301  USA
  24  *
  25  */
  26
  27 #include <linux/config.h>
  28 #include <linux/module.h>
  29 #include <linux/errno.h>
  30 #include <linux/fs.h>
  31 #include <linux/parser.h>
  32 #include <linux/idr.h>
  33
  34 #include "debug.h"
  35 #include "v9fs.h"
  36 #include "9p.h"
  37 #include "v9fs_vfs.h"
  38 #include "transport.h"
  39 #include "mux.h"
  40 #include "conv.h"
  41
  42 /* TODO: sysfs or debugfs interface */
  43 int v9fs_debug_level = 0;       /* feature-rific global debug level  */
  44
  45 /*
  46   * Option Parsing (code inspired by NFS code)
  47   *
  48   */
  49
  50 enum {
  51         /* Options that take integer arguments */
  52         Opt_port, Opt_msize, Opt_uid, Opt_gid, Opt_afid, Opt_debug,
  53         Opt_rfdno, Opt_wfdno,
  54         /* String options */
  55         Opt_name, Opt_remotename,
  56         /* Options that take no arguments */
  57         Opt_legacy, Opt_nodevmap, Opt_unix, Opt_tcp, Opt_fd,
  58         /* Error token */
  59         Opt_err
  60 };
  61
  62 static match_table_t tokens = {
  63         {Opt_port, "port=%u"},
  64         {Opt_msize, "msize=%u"},
  65         {Opt_uid, "uid=%u"},
  66         {Opt_gid, "gid=%u"},
  67         {Opt_afid, "afid=%u"},
  68         {Opt_rfdno, "rfdno=%u"},
  69         {Opt_wfdno, "wfdno=%u"},
  70         {Opt_debug, "debug=%u"},
  71         {Opt_name, "name=%s"},
  72         {Opt_remotename, "aname=%s"},
  73         {Opt_unix, "proto=unix"},
  74         {Opt_tcp, "proto=tcp"},
  75         {Opt_fd, "proto=fd"},
  76         {Opt_tcp, "tcp"},
  77         {Opt_unix, "unix"},
  78         {Opt_fd, "fd"},
  79         {Opt_legacy, "noextend"},
  80         {Opt_nodevmap, "nodevmap"},
  81         {Opt_err, NULL}
  82 };
  83
  84 /*
  85  *  Parse option string.
  86  */
  87
  88 /**
  89  * v9fs_parse_options - parse mount options into session structure
  90  * @options: options string passed from mount
  91  * @v9ses: existing v9fs session information
  92  *
  93  */
  94
  95 static void v9fs_parse_options(char *options, struct v9fs_session_info *v9ses)
  96 {
  97         char *p;
  98         substring_t args[MAX_OPT_ARGS];
  99         int option;
 100         int ret;
 101
 102         /* setup defaults */
 103         v9ses->port = V9FS_PORT;
 104         v9ses->maxdata = 9000;
 105         v9ses->proto = PROTO_TCP;
 106         v9ses->extended = 1;
 107         v9ses->afid = ~0;
 108         v9ses->debug = 0;
 109         v9ses->rfdno = ~0;
 110         v9ses->wfdno = ~0;
 111
 112         if (!options)
 113                 return;
 114
 115         while ((p = strsep(&options, ",")) != NULL) {
 116                 int token;
 117                 if (!*p)
 118                         continue;
 119                 token = match_token(p, tokens, args);
 120                 if (token < Opt_name) {
 121                         if ((ret = match_int(&args[0], &option)) < 0) {
 122                                 dprintk(DEBUG_ERROR,
 123                                         "integer field, but no integer?\n");
 124                                 continue;
 125                         }
 126
 127                 }
 128                 switch (token) {
 129                 case Opt_port:
 130                         v9ses->port = option;
 131                         break;
 132                 case Opt_msize:
 133                         v9ses->maxdata = option;
 134                         break;
 135                 case Opt_uid:
 136                         v9ses->uid = option;
 137                         break;
 138                 case Opt_gid:
 139                         v9ses->gid = option;
 140                         break;
 141                 case Opt_afid:
 142                         v9ses->afid = option;
 143                         break;
 144                 case Opt_rfdno:
 145                         v9ses->rfdno = option;
 146                         break;
 147                 case Opt_wfdno:
 148                         v9ses->wfdno = option;
 149                         break;
 150                 case Opt_debug:
 151                         v9ses->debug = option;
 152                         break;
 153                 case Opt_tcp:
 154                         v9ses->proto = PROTO_TCP;
 155                         break;
 156                 case Opt_unix:
 157                         v9ses->proto = PROTO_UNIX;
 158                         break;
 159                 case Opt_fd:
 160                         v9ses->proto = PROTO_FD;
 161                         break;
 162                 case Opt_name:
 163                         match_strcpy(v9ses->name, &args[0]);
 164                         break;
 165                 case Opt_remotename:
 166                         match_strcpy(v9ses->remotename, &args[0]);
 167                         break;
 168                 case Opt_legacy:
 169                         v9ses->extended = 0;
 170                         break;
 171                 case Opt_nodevmap:
 172                         v9ses->nodev = 1;
 173                         break;
 174                 default:
 175                         continue;
 176                 }
 177         }
 178 }
 179
 180 /**
 181  * v9fs_inode2v9ses - safely extract v9fs session info from super block
 182  * @inode: inode to extract information from
 183  *
 184  * Paranoid function to extract v9ses information from superblock,
 185  * if anything is missing it will report an error.
 186  *
 187  */
 188
 189 struct v9fs_session_info *v9fs_inode2v9ses(struct inode *inode)
 190 {
 191         return (inode->i_sb->s_fs_info);
 192 }
 193
 194 /**
 195  * v9fs_get_idpool - allocate numeric id from pool
 196  * @p - pool to allocate from
 197  *
 198  * XXX - This seems to be an awful generic function, should it be in idr.c with
 199  *            the lock included in struct idr?
 200  */
 201
 202 int v9fs_get_idpool(struct v9fs_idpool *p)
 203 {
 204         int i = 0;
 205         int error;
 206
 207 retry:
 208         if (idr_pre_get(&p->pool, GFP_KERNEL) == 0)
 209                 return 0;
 210
 211         if (down_interruptible(&p->lock) == -EINTR) {
 212                 eprintk(KERN_WARNING, "Interrupted while locking\n");
 213                 return -1;
 214         }
 215
 216         /* no need to store exactly p, we just need something non-null */
 217         error = idr_get_new(&p->pool, p, &i);
 218         up(&p->lock);
 219
 220         if (error == -EAGAIN)
 221                 goto retry;
 222         else if (error)
 223                 return -1;
 224
 225         return i;
 226 }
 227
 228 /**
 229  * v9fs_put_idpool - release numeric id from pool
 230  * @p - pool to allocate from
 231  *
 232  * XXX - This seems to be an awful generic function, should it be in idr.c with
 233  *            the lock included in struct idr?
 234  */
 235
 236 void v9fs_put_idpool(int id, struct v9fs_idpool *p)
 237 {
 238         if (down_interruptible(&p->lock) == -EINTR) {
 239                 eprintk(KERN_WARNING, "Interrupted while locking\n");
 240                 return;
 241         }
 242         idr_remove(&p->pool, id);
 243         up(&p->lock);
 244 }
 245
 246 /**
 247  * v9fs_check_idpool - check if the specified id is available
 248  * @id - id to check
 249  * @p - pool
 250  */
 251 int v9fs_check_idpool(int id, struct v9fs_idpool *p)
 252 {
 253         return idr_find(&p->pool, id) != NULL;
 254 }
 255
 256 /**
 257  * v9fs_session_init - initialize session
 258  * @v9ses: session information structure
 259  * @dev_name: device being mounted
 260  * @data: options
 261  *
 262  */
 263
 264 int
 265 v9fs_session_init(struct v9fs_session_info *v9ses,
 266                   const char *dev_name, char *data)
 267 {
 268         struct v9fs_fcall *fcall = NULL;
 269         struct v9fs_transport *trans_proto;
 270         int n = 0;
 271         int newfid = -1;
 272         int retval = -EINVAL;
 273
 274         v9ses->name = __getname();
 275         if (!v9ses->name)
 276                 return -ENOMEM;
 277
 278         v9ses->remotename = __getname();
 279         if (!v9ses->remotename) {
 280                 __putname(v9ses->name);
 281                 return -ENOMEM;
 282         }
 283
 284         strcpy(v9ses->name, V9FS_DEFUSER);
 285         strcpy(v9ses->remotename, V9FS_DEFANAME);
 286
 287         v9fs_parse_options(data, v9ses);
 288
 289         /* set global debug level */
 290         v9fs_debug_level = v9ses->debug;
 291
 292         /* id pools that are session-dependent: FIDs and TIDs */
 293         idr_init(&v9ses->fidpool.pool);
 294         init_MUTEX(&v9ses->fidpool.lock);
 295
 296         switch (v9ses->proto) {
 297         case PROTO_TCP:
 298                 trans_proto = &v9fs_trans_tcp;
 299                 break;
 300         case PROTO_UNIX:
 301                 trans_proto = &v9fs_trans_unix;
 302                 *v9ses->remotename = 0;
 303                 break;
 304         case PROTO_FD:
 305                 trans_proto = &v9fs_trans_fd;
 306                 *v9ses->remotename = 0;
 307                 break;
 308         default:
 309                 printk(KERN_ERR "v9fs: Bad mount protocol %d\n", v9ses->proto);
 310                 retval = -ENOPROTOOPT;
 311                 goto SessCleanUp;
 312         };
 313
 314         v9ses->transport = kmalloc(sizeof(*v9ses->transport), GFP_KERNEL);
 315         if (!v9ses->transport) {
 316                 retval = -ENOMEM;
 317                 goto SessCleanUp;
 318         }
 319
 320         memmove(v9ses->transport, trans_proto, sizeof(*v9ses->transport));
 321
 322         if ((retval = v9ses->transport->init(v9ses, dev_name, data)) < 0) {
 323                 eprintk(KERN_ERR, "problem initializing transport\n");
 324                 goto SessCleanUp;
 325         }
 326
 327         v9ses->inprogress = 0;
 328         v9ses->shutdown = 0;
 329         v9ses->session_hung = 0;
 330
 331         v9ses->mux = v9fs_mux_init(v9ses->transport, v9ses->maxdata + V9FS_IOHDRSZ,
 332                 &v9ses->extended);
 333
 334         if (IS_ERR(v9ses->mux)) {
 335                 retval = PTR_ERR(v9ses->mux);
 336                 v9ses->mux = NULL;
 337                 dprintk(DEBUG_ERROR, "problem initializing mux\n");
 338                 goto SessCleanUp;
 339         }
 340
 341         if (v9ses->afid == ~0) {
 342                 if (v9ses->extended)
 343                         retval =
 344                             v9fs_t_version(v9ses, v9ses->maxdata, "9P2000.u",
 345                                            &fcall);
 346                 else
 347                         retval = v9fs_t_version(v9ses, v9ses->maxdata, "9P2000",
 348                                                 &fcall);
 349
 350                 if (retval < 0) {
 351                         dprintk(DEBUG_ERROR, "v9fs_t_version failed\n");
 352                         goto FreeFcall;
 353                 }
 354
 355                 /* Really should check for 9P1 and report error */
 356                 if (!strcmp(fcall->params.rversion.version, "9P2000.u")) {
 357                         dprintk(DEBUG_9P, "9P2000 UNIX extensions enabled\n");
 358                         v9ses->extended = 1;
 359                 } else {
 360                         dprintk(DEBUG_9P, "9P2000 legacy mode enabled\n");
 361                         v9ses->extended = 0;
 362                 }
 363
 364                 n = fcall->params.rversion.msize;
 365                 kfree(fcall);
 366
 367                 if (n < v9ses->maxdata)
 368                         v9ses->maxdata = n;
 369         }
 370
 371         newfid = v9fs_get_idpool(&v9ses->fidpool);
 372         if (newfid < 0) {
 373                 eprintk(KERN_WARNING, "couldn't allocate FID\n");
 374                 retval = -ENOMEM;
 375                 goto SessCleanUp;
 376         }
 377         /* it is a little bit ugly, but we have to prevent newfid */
 378         /* being the same as afid, so if it is, get a new fid     */
 379         if (v9ses->afid != ~0 && newfid == v9ses->afid) {
 380                 newfid = v9fs_get_idpool(&v9ses->fidpool);
 381                 if (newfid < 0) {
 382                         eprintk(KERN_WARNING, "couldn't allocate FID\n");
 383                         retval = -ENOMEM;
 384                         goto SessCleanUp;
 385                 }
 386         }
 387
 388         if ((retval =
 389              v9fs_t_attach(v9ses, v9ses->name, v9ses->remotename, newfid,
 390                            v9ses->afid, NULL))
 391             < 0) {
 392                 dprintk(DEBUG_ERROR, "cannot attach\n");
 393                 goto SessCleanUp;
 394         }
 395
 396         if (v9ses->afid != ~0) {
 397                 if (v9fs_t_clunk(v9ses, v9ses->afid))
 398                         dprintk(DEBUG_ERROR, "clunk failed\n");
 399         }
 400
 401         return newfid;
 402
 403       FreeFcall:
 404         kfree(fcall);
 405
 406       SessCleanUp:
 407         v9fs_session_close(v9ses);
 408         return retval;
 409 }
 410
 411 /**
 412  * v9fs_session_close - shutdown a session
 413  * @v9ses: session information structure
 414  *
 415  */
 416
 417 void v9fs_session_close(struct v9fs_session_info *v9ses)
 418 {
 419         if (v9ses->mux) {
 420                 v9fs_mux_destroy(v9ses->mux);
 421                 v9ses->mux = NULL;
 422         }
 423
 424         if (v9ses->transport) {
 425                 v9ses->transport->close(v9ses->transport);
 426                 kfree(v9ses->transport);
 427                 v9ses->transport = NULL;
 428         }
 429
 430         __putname(v9ses->name);
 431         __putname(v9ses->remotename);
 432 }
 433
 434 /**
 435  * v9fs_session_cancel - mark transport as disconnected
 436  *      and cancel all pending requests.
 437  */
 438 void v9fs_session_cancel(struct v9fs_session_info *v9ses) {
 439         dprintk(DEBUG_ERROR, "cancel session %p\n", v9ses);
 440         v9ses->transport->status = Disconnected;
 441         v9fs_mux_cancel(v9ses->mux, -EIO);
 442 }
 443
 444 extern int v9fs_error_init(void);
 445
 446 /**
 447  * v9fs_init - Initialize module
 448  *
 449  */
 450
 451 static int __init init_v9fs(void)
 452 {
 453         v9fs_error_init();
 454
 455         printk(KERN_INFO "Installing v9fs 9P2000 file system support\n");
 456
 457         v9fs_mux_global_init();
 458         return register_filesystem(&v9fs_fs_type);
 459 }
 460
 461 /**
 462  * v9fs_init - shutdown module
 463  *
 464  */
 465
 466 static void __exit exit_v9fs(void)
 467 {
 468         v9fs_mux_global_exit();
 469         unregister_filesystem(&v9fs_fs_type);
 470 }
 471
 472 module_init(init_v9fs)
 473 module_exit(exit_v9fs)
 474
 475 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
 476 MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
 477 MODULE_LICENSE("GPL");