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
  41 /* TODO: sysfs or debugfs interface */
  42 int v9fs_debug_level = 0;       /* feature-rific global debug level  */
  43
  44 /*
  45   * Option Parsing (code inspired by NFS code)
  46   *
  47   */
  48
  49 enum {
  50         /* Options that take integer arguments */
  51         Opt_port, Opt_msize, Opt_uid, Opt_gid, Opt_afid, Opt_debug,
  52         Opt_rfdno, Opt_wfdno,
  53         /* String options */
  54         Opt_name, Opt_remotename,
  55         /* Options that take no arguments */
  56         Opt_legacy, Opt_nodevmap, Opt_unix, Opt_tcp, Opt_fd,
  57         /* Error token */
  58         Opt_err
  59 };
  60
  61 static match_table_t tokens = {
  62         {Opt_port, "port=%u"},
  63         {Opt_msize, "msize=%u"},
  64         {Opt_uid, "uid=%u"},
  65         {Opt_gid, "gid=%u"},
  66         {Opt_afid, "afid=%u"},
  67         {Opt_rfdno, "rfdno=%u"},
  68         {Opt_wfdno, "wfdno=%u"},
  69         {Opt_debug, "debug=%x"},
  70         {Opt_name, "name=%s"},
  71         {Opt_remotename, "aname=%s"},
  72         {Opt_unix, "proto=unix"},
  73         {Opt_tcp, "proto=tcp"},
  74         {Opt_fd, "proto=fd"},
  75         {Opt_tcp, "tcp"},
  76         {Opt_unix, "unix"},
  77         {Opt_fd, "fd"},
  78         {Opt_legacy, "noextend"},
  79         {Opt_nodevmap, "nodevmap"},
  80         {Opt_err, NULL}
  81 };
  82
  83 /*
  84  *  Parse option string.
  85  */
  86
  87 /**
  88  * v9fs_parse_options - parse mount options into session structure
  89  * @options: options string passed from mount
  90  * @v9ses: existing v9fs session information
  91  *
  92  */
  93
  94 static void v9fs_parse_options(char *options, struct v9fs_session_info *v9ses)
  95 {
  96         char *p;
  97         substring_t args[MAX_OPT_ARGS];
  98         int option;
  99         int ret;
 100
 101         /* setup defaults */
 102         v9ses->port = V9FS_PORT;
 103         v9ses->maxdata = 9000;
 104         v9ses->proto = PROTO_TCP;
 105         v9ses->extended = 1;
 106         v9ses->afid = ~0;
 107         v9ses->debug = 0;
 108         v9ses->rfdno = ~0;
 109         v9ses->wfdno = ~0;
 110
 111         if (!options)
 112                 return;
 113
 114         while ((p = strsep(&options, ",")) != NULL) {
 115                 int token;
 116                 if (!*p)
 117                         continue;
 118                 token = match_token(p, tokens, args);
 119                 if (token < Opt_name) {
 120                         if ((ret = match_int(&args[0], &option)) < 0) {
 121                                 dprintk(DEBUG_ERROR,
 122                                         "integer field, but no integer?\n");
 123                                 continue;
 124                         }
 125
 126                 }
 127                 switch (token) {
 128                 case Opt_port:
 129                         v9ses->port = option;
 130                         break;
 131                 case Opt_msize:
 132                         v9ses->maxdata = option;
 133                         break;
 134                 case Opt_uid:
 135                         v9ses->uid = option;
 136                         break;
 137                 case Opt_gid:
 138                         v9ses->gid = option;
 139                         break;
 140                 case Opt_afid:
 141                         v9ses->afid = option;
 142                         break;
 143                 case Opt_rfdno:
 144                         v9ses->rfdno = option;
 145                         break;
 146                 case Opt_wfdno:
 147                         v9ses->wfdno = option;
 148                         break;
 149                 case Opt_debug:
 150                         v9ses->debug = option;
 151                         break;
 152                 case Opt_tcp:
 153                         v9ses->proto = PROTO_TCP;
 154                         break;
 155                 case Opt_unix:
 156                         v9ses->proto = PROTO_UNIX;
 157                         break;
 158                 case Opt_fd:
 159                         v9ses->proto = PROTO_FD;
 160                         break;
 161                 case Opt_name:
 162                         match_strcpy(v9ses->name, &args[0]);
 163                         break;
 164                 case Opt_remotename:
 165                         match_strcpy(v9ses->remotename, &args[0]);
 166                         break;
 167                 case Opt_legacy:
 168                         v9ses->extended = 0;
 169                         break;
 170                 case Opt_nodevmap:
 171                         v9ses->nodev = 1;
 172                         break;
 173                 default:
 174                         continue;
 175                 }
 176         }
 177 }
 178
 179 /**
 180  * v9fs_inode2v9ses - safely extract v9fs session info from super block
 181  * @inode: inode to extract information from
 182  *
 183  * Paranoid function to extract v9ses information from superblock,
 184  * if anything is missing it will report an error.
 185  *
 186  */
 187
 188 struct v9fs_session_info *v9fs_inode2v9ses(struct inode *inode)
 189 {
 190         return (inode->i_sb->s_fs_info);
 191 }
 192
 193 /**
 194  * v9fs_get_idpool - allocate numeric id from pool
 195  * @p - pool to allocate from
 196  *
 197  * XXX - This seems to be an awful generic function, should it be in idr.c with
 198  *            the lock included in struct idr?
 199  */
 200
 201 int v9fs_get_idpool(struct v9fs_idpool *p)
 202 {
 203         int i = 0;
 204         int error;
 205
 206 retry:
 207         if (idr_pre_get(&p->pool, GFP_KERNEL) == 0)
 208                 return 0;
 209
 210         if (down_interruptible(&p->lock) == -EINTR) {
 211                 eprintk(KERN_WARNING, "Interrupted while locking\n");
 212                 return -1;
 213         }
 214
 215         /* no need to store exactly p, we just need something non-null */
 216         error = idr_get_new(&p->pool, p, &i);
 217         up(&p->lock);
 218
 219         if (error == -EAGAIN)
 220                 goto retry;
 221         else if (error)
 222                 return -1;
 223
 224         return i;
 225 }
 226
 227 /**
 228  * v9fs_put_idpool - release numeric id from pool
 229  * @p - pool to allocate from
 230  *
 231  * XXX - This seems to be an awful generic function, should it be in idr.c with
 232  *            the lock included in struct idr?
 233  */
 234
 235 void v9fs_put_idpool(int id, struct v9fs_idpool *p)
 236 {
 237         if (down_interruptible(&p->lock) == -EINTR) {
 238                 eprintk(KERN_WARNING, "Interrupted while locking\n");
 239                 return;
 240         }
 241         idr_remove(&p->pool, id);
 242         up(&p->lock);
 243 }
 244
 245 /**
 246  * v9fs_check_idpool - check if the specified id is available
 247  * @id - id to check
 248  * @p - pool
 249  */
 250 int v9fs_check_idpool(int id, struct v9fs_idpool *p)
 251 {
 252         return idr_find(&p->pool, id) != NULL;
 253 }
 254
 255 /**
 256  * v9fs_session_init - initialize session
 257  * @v9ses: session information structure
 258  * @dev_name: device being mounted
 259  * @data: options
 260  *
 261  */
 262
 263 int
 264 v9fs_session_init(struct v9fs_session_info *v9ses,
 265                   const char *dev_name, char *data)
 266 {
 267         struct v9fs_fcall *fcall = NULL;
 268         struct v9fs_transport *trans_proto;
 269         int n = 0;
 270         int newfid = -1;
 271         int retval = -EINVAL;
 272         struct v9fs_str *version;
 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                 version = &fcall->params.rversion.version;
 356                 if (version->len==8 && !memcmp(version->str, "9P2000.u", 8)) {
 357                         dprintk(DEBUG_9P, "9P2000 UNIX extensions enabled\n");
 358                         v9ses->extended = 1;
 359                 } else if (version->len==6 && !memcmp(version->str, "9P2000", 6)) {
 360                         dprintk(DEBUG_9P, "9P2000 legacy mode enabled\n");
 361                         v9ses->extended = 0;
 362                 } else {
 363                         retval = -EREMOTEIO;
 364                         goto FreeFcall;
 365                 }
 366
 367                 n = fcall->params.rversion.msize;
 368                 kfree(fcall);
 369
 370                 if (n < v9ses->maxdata)
 371                         v9ses->maxdata = n;
 372         }
 373
 374         newfid = v9fs_get_idpool(&v9ses->fidpool);
 375         if (newfid < 0) {
 376                 eprintk(KERN_WARNING, "couldn't allocate FID\n");
 377                 retval = -ENOMEM;
 378                 goto SessCleanUp;
 379         }
 380         /* it is a little bit ugly, but we have to prevent newfid */
 381         /* being the same as afid, so if it is, get a new fid     */
 382         if (v9ses->afid != ~0 && newfid == v9ses->afid) {
 383                 newfid = v9fs_get_idpool(&v9ses->fidpool);
 384                 if (newfid < 0) {
 385                         eprintk(KERN_WARNING, "couldn't allocate FID\n");
 386                         retval = -ENOMEM;
 387                         goto SessCleanUp;
 388                 }
 389         }
 390
 391         if ((retval =
 392              v9fs_t_attach(v9ses, v9ses->name, v9ses->remotename, newfid,
 393                            v9ses->afid, NULL))
 394             < 0) {
 395                 dprintk(DEBUG_ERROR, "cannot attach\n");
 396                 goto SessCleanUp;
 397         }
 398
 399         if (v9ses->afid != ~0) {
 400                 dprintk(DEBUG_ERROR, "afid not equal to ~0\n");
 401                 if (v9fs_t_clunk(v9ses, v9ses->afid))
 402                         dprintk(DEBUG_ERROR, "clunk failed\n");
 403         }
 404
 405         return newfid;
 406
 407       FreeFcall:
 408         kfree(fcall);
 409
 410       SessCleanUp:
 411         v9fs_session_close(v9ses);
 412         return retval;
 413 }
 414
 415 /**
 416  * v9fs_session_close - shutdown a session
 417  * @v9ses: session information structure
 418  *
 419  */
 420
 421 void v9fs_session_close(struct v9fs_session_info *v9ses)
 422 {
 423         if (v9ses->mux) {
 424                 v9fs_mux_destroy(v9ses->mux);
 425                 v9ses->mux = NULL;
 426         }
 427
 428         if (v9ses->transport) {
 429                 v9ses->transport->close(v9ses->transport);
 430                 kfree(v9ses->transport);
 431                 v9ses->transport = NULL;
 432         }
 433
 434         __putname(v9ses->name);
 435         __putname(v9ses->remotename);
 436 }
 437
 438 /**
 439  * v9fs_session_cancel - mark transport as disconnected
 440  *      and cancel all pending requests.
 441  */
 442 void v9fs_session_cancel(struct v9fs_session_info *v9ses) {
 443         dprintk(DEBUG_ERROR, "cancel session %p\n", v9ses);
 444         v9ses->transport->status = Disconnected;
 445         v9fs_mux_cancel(v9ses->mux, -EIO);
 446 }
 447
 448 extern int v9fs_error_init(void);
 449
 450 /**
 451  * v9fs_init - Initialize module
 452  *
 453  */
 454
 455 static int __init init_v9fs(void)
 456 {
 457         int ret;
 458
 459         v9fs_error_init();
 460
 461         printk(KERN_INFO "Installing v9fs 9P2000 file system support\n");
 462
 463         ret = v9fs_mux_global_init();
 464         if (!ret)
 465                 ret = register_filesystem(&v9fs_fs_type);
 466
 467         return ret;
 468 }
 469
 470 /**
 471  * v9fs_init - shutdown module
 472  *
 473  */
 474
 475 static void __exit exit_v9fs(void)
 476 {
 477         v9fs_mux_global_exit();
 478         unregister_filesystem(&v9fs_fs_type);
 479 }
 480
 481 module_init(init_v9fs)
 482 module_exit(exit_v9fs)
 483
 484 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
 485 MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
 486 MODULE_LICENSE("GPL");