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 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
  33 #include "debug.h"
  34 #include "v9fs.h"
  35 #include "9p.h"
  36 #include "v9fs_vfs.h"
  37 #include "transport.h"
  38 #include "mux.h"
  39
  40 /* TODO: sysfs or debugfs interface */
  41 int v9fs_debug_level = 0;       /* feature-rific global debug level  */
  42
  43 /*
  44   * Option Parsing (code inspired by NFS code)
  45   *
  46   */
  47
  48 enum {
  49         /* Options that take integer arguments */
  50         Opt_port, Opt_msize, Opt_uid, Opt_gid, Opt_afid, Opt_debug,
  51         Opt_rfdno, Opt_wfdno,
  52         /* String options */
  53         Opt_uname, Opt_remotename,
  54         /* Options that take no arguments */
  55         Opt_legacy, Opt_nodevmap, Opt_unix, Opt_tcp, Opt_fd,
  56         /* Cache options */
  57         Opt_cache_loose,
  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=%x"},
  71         {Opt_uname, "uname=%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_cache_loose, "cache=loose"},
  82         {Opt_cache_loose, "loose"},
  83         {Opt_err, NULL}
  84 };
  85
  86 /*
  87  *  Parse option string.
  88  */
  89
  90 /**
  91  * v9fs_parse_options - parse mount options into session structure
  92  * @options: options string passed from mount
  93  * @v9ses: existing v9fs session information
  94  *
  95  */
  96
  97 static void v9fs_parse_options(char *options, struct v9fs_session_info *v9ses)
  98 {
  99         char *p;
 100         substring_t args[MAX_OPT_ARGS];
 101         int option;
 102         int ret;
 103
 104         /* setup defaults */
 105         v9ses->port = V9FS_PORT;
 106         v9ses->maxdata = 9000;
 107         v9ses->proto = PROTO_TCP;
 108         v9ses->extended = 1;
 109         v9ses->afid = ~0;
 110         v9ses->debug = 0;
 111         v9ses->rfdno = ~0;
 112         v9ses->wfdno = ~0;
 113         v9ses->cache = 0;
 114
 115         if (!options)
 116                 return;
 117
 118         while ((p = strsep(&options, ",")) != NULL) {
 119                 int token;
 120                 if (!*p)
 121                         continue;
 122                 token = match_token(p, tokens, args);
 123                 if (token < Opt_uname) {
 124                         if ((ret = match_int(&args[0], &option)) < 0) {
 125                                 dprintk(DEBUG_ERROR,
 126                                         "integer field, but no integer?\n");
 127                                 continue;
 128                         }
 129                 }
 130                 switch (token) {
 131                 case Opt_port:
 132                         v9ses->port = option;
 133                         break;
 134                 case Opt_msize:
 135                         v9ses->maxdata = option;
 136                         break;
 137                 case Opt_uid:
 138                         v9ses->uid = option;
 139                         break;
 140                 case Opt_gid:
 141                         v9ses->gid = option;
 142                         break;
 143                 case Opt_afid:
 144                         v9ses->afid = option;
 145                         break;
 146                 case Opt_rfdno:
 147                         v9ses->rfdno = option;
 148                         break;
 149                 case Opt_wfdno:
 150                         v9ses->wfdno = option;
 151                         break;
 152                 case Opt_debug:
 153                         v9ses->debug = option;
 154                         break;
 155                 case Opt_tcp:
 156                         v9ses->proto = PROTO_TCP;
 157                         break;
 158                 case Opt_unix:
 159                         v9ses->proto = PROTO_UNIX;
 160                         break;
 161                 case Opt_fd:
 162                         v9ses->proto = PROTO_FD;
 163                         break;
 164                 case Opt_uname:
 165                         match_strcpy(v9ses->name, &args[0]);
 166                         break;
 167                 case Opt_remotename:
 168                         match_strcpy(v9ses->remotename, &args[0]);
 169                         break;
 170                 case Opt_legacy:
 171                         v9ses->extended = 0;
 172                         break;
 173                 case Opt_nodevmap:
 174                         v9ses->nodev = 1;
 175                         break;
 176                 case Opt_cache_loose:
 177                         v9ses->cache = CACHE_LOOSE;
 178                         break;
 179                 default:
 180                         continue;
 181                 }
 182         }
 183 }
 184
 185 /**
 186  * v9fs_inode2v9ses - safely extract v9fs session info from super block
 187  * @inode: inode to extract information from
 188  *
 189  * Paranoid function to extract v9ses information from superblock,
 190  * if anything is missing it will report an error.
 191  *
 192  */
 193
 194 struct v9fs_session_info *v9fs_inode2v9ses(struct inode *inode)
 195 {
 196         return (inode->i_sb->s_fs_info);
 197 }
 198
 199 /**
 200  * v9fs_get_idpool - allocate numeric id from pool
 201  * @p - pool to allocate from
 202  *
 203  * XXX - This seems to be an awful generic function, should it be in idr.c with
 204  *            the lock included in struct idr?
 205  */
 206
 207 int v9fs_get_idpool(struct v9fs_idpool *p)
 208 {
 209         int i = 0;
 210         int error;
 211
 212 retry:
 213         if (idr_pre_get(&p->pool, GFP_KERNEL) == 0)
 214                 return 0;
 215
 216         if (down_interruptible(&p->lock) == -EINTR) {
 217                 eprintk(KERN_WARNING, "Interrupted while locking\n");
 218                 return -1;
 219         }
 220
 221         /* no need to store exactly p, we just need something non-null */
 222         error = idr_get_new(&p->pool, p, &i);
 223         up(&p->lock);
 224
 225         if (error == -EAGAIN)
 226                 goto retry;
 227         else if (error)
 228                 return -1;
 229
 230         return i;
 231 }
 232
 233 /**
 234  * v9fs_put_idpool - release numeric id from pool
 235  * @p - pool to allocate from
 236  *
 237  * XXX - This seems to be an awful generic function, should it be in idr.c with
 238  *            the lock included in struct idr?
 239  */
 240
 241 void v9fs_put_idpool(int id, struct v9fs_idpool *p)
 242 {
 243         if (down_interruptible(&p->lock) == -EINTR) {
 244                 eprintk(KERN_WARNING, "Interrupted while locking\n");
 245                 return;
 246         }
 247         idr_remove(&p->pool, id);
 248         up(&p->lock);
 249 }
 250
 251 /**
 252  * v9fs_check_idpool - check if the specified id is available
 253  * @id - id to check
 254  * @p - pool
 255  */
 256 int v9fs_check_idpool(int id, struct v9fs_idpool *p)
 257 {
 258         return idr_find(&p->pool, id) != NULL;
 259 }
 260
 261 /**
 262  * v9fs_session_init - initialize session
 263  * @v9ses: session information structure
 264  * @dev_name: device being mounted
 265  * @data: options
 266  *
 267  */
 268
 269 int
 270 v9fs_session_init(struct v9fs_session_info *v9ses,
 271                   const char *dev_name, char *data)
 272 {
 273         struct v9fs_fcall *fcall = NULL;
 274         struct v9fs_transport *trans_proto;
 275         int n = 0;
 276         int newfid = -1;
 277         int retval = -EINVAL;
 278         struct v9fs_str *version;
 279
 280         v9ses->name = __getname();
 281         if (!v9ses->name)
 282                 return -ENOMEM;
 283
 284         v9ses->remotename = __getname();
 285         if (!v9ses->remotename) {
 286                 __putname(v9ses->name);
 287                 return -ENOMEM;
 288         }
 289
 290         strcpy(v9ses->name, V9FS_DEFUSER);
 291         strcpy(v9ses->remotename, V9FS_DEFANAME);
 292
 293         v9fs_parse_options(data, v9ses);
 294
 295         /* set global debug level */
 296         v9fs_debug_level = v9ses->debug;
 297
 298         /* id pools that are session-dependent: fids and tags */
 299         idr_init(&v9ses->fidpool.pool);
 300         init_MUTEX(&v9ses->fidpool.lock);
 301
 302         switch (v9ses->proto) {
 303         case PROTO_TCP:
 304                 trans_proto = &v9fs_trans_tcp;
 305                 break;
 306         case PROTO_UNIX:
 307                 trans_proto = &v9fs_trans_unix;
 308                 *v9ses->remotename = 0;
 309                 break;
 310         case PROTO_FD:
 311                 trans_proto = &v9fs_trans_fd;
 312                 *v9ses->remotename = 0;
 313                 break;
 314         default:
 315                 printk(KERN_ERR "v9fs: Bad mount protocol %d\n", v9ses->proto);
 316                 retval = -ENOPROTOOPT;
 317                 goto SessCleanUp;
 318         };
 319
 320         v9ses->transport = kmalloc(sizeof(*v9ses->transport), GFP_KERNEL);
 321         if (!v9ses->transport) {
 322                 retval = -ENOMEM;
 323                 goto SessCleanUp;
 324         }
 325
 326         memmove(v9ses->transport, trans_proto, sizeof(*v9ses->transport));
 327
 328         if ((retval = v9ses->transport->init(v9ses, dev_name, data)) < 0) {
 329                 eprintk(KERN_ERR, "problem initializing transport\n");
 330                 goto SessCleanUp;
 331         }
 332
 333         v9ses->inprogress = 0;
 334         v9ses->shutdown = 0;
 335         v9ses->session_hung = 0;
 336
 337         v9ses->mux = v9fs_mux_init(v9ses->transport, v9ses->maxdata + V9FS_IOHDRSZ,
 338                 &v9ses->extended);
 339
 340         if (IS_ERR(v9ses->mux)) {
 341                 retval = PTR_ERR(v9ses->mux);
 342                 v9ses->mux = NULL;
 343                 dprintk(DEBUG_ERROR, "problem initializing mux\n");
 344                 goto SessCleanUp;
 345         }
 346
 347         if (v9ses->afid == ~0) {
 348                 if (v9ses->extended)
 349                         retval =
 350                             v9fs_t_version(v9ses, v9ses->maxdata, "9P2000.u",
 351                                            &fcall);
 352                 else
 353                         retval = v9fs_t_version(v9ses, v9ses->maxdata, "9P2000",
 354                                                 &fcall);
 355
 356                 if (retval < 0) {
 357                         dprintk(DEBUG_ERROR, "v9fs_t_version failed\n");
 358                         goto FreeFcall;
 359                 }
 360
 361                 version = &fcall->params.rversion.version;
 362                 if (version->len==8 && !memcmp(version->str, "9P2000.u", 8)) {
 363                         dprintk(DEBUG_9P, "9P2000 UNIX extensions enabled\n");
 364                         v9ses->extended = 1;
 365                 } else if (version->len==6 && !memcmp(version->str, "9P2000", 6)) {
 366                         dprintk(DEBUG_9P, "9P2000 legacy mode enabled\n");
 367                         v9ses->extended = 0;
 368                 } else {
 369                         retval = -EREMOTEIO;
 370                         goto FreeFcall;
 371                 }
 372
 373                 n = fcall->params.rversion.msize;
 374                 kfree(fcall);
 375
 376                 if (n < v9ses->maxdata)
 377                         v9ses->maxdata = n;
 378         }
 379
 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         /* it is a little bit ugly, but we have to prevent newfid */
 387         /* being the same as afid, so if it is, get a new fid     */
 388         if (v9ses->afid != ~0 && newfid == v9ses->afid) {
 389                 newfid = v9fs_get_idpool(&v9ses->fidpool);
 390                 if (newfid < 0) {
 391                         eprintk(KERN_WARNING, "couldn't allocate FID\n");
 392                         retval = -ENOMEM;
 393                         goto SessCleanUp;
 394                 }
 395         }
 396
 397         if ((retval =
 398              v9fs_t_attach(v9ses, v9ses->name, v9ses->remotename, newfid,
 399                            v9ses->afid, NULL))
 400             < 0) {
 401                 dprintk(DEBUG_ERROR, "cannot attach\n");
 402                 goto SessCleanUp;
 403         }
 404
 405         if (v9ses->afid != ~0) {
 406                 dprintk(DEBUG_ERROR, "afid not equal to ~0\n");
 407                 if (v9fs_t_clunk(v9ses, v9ses->afid))
 408                         dprintk(DEBUG_ERROR, "clunk failed\n");
 409         }
 410
 411         return newfid;
 412
 413       FreeFcall:
 414         kfree(fcall);
 415
 416       SessCleanUp:
 417         v9fs_session_close(v9ses);
 418         return retval;
 419 }
 420
 421 /**
 422  * v9fs_session_close - shutdown a session
 423  * @v9ses: session information structure
 424  *
 425  */
 426
 427 void v9fs_session_close(struct v9fs_session_info *v9ses)
 428 {
 429         if (v9ses->mux) {
 430                 v9fs_mux_destroy(v9ses->mux);
 431                 v9ses->mux = NULL;
 432         }
 433
 434         if (v9ses->transport) {
 435                 v9ses->transport->close(v9ses->transport);
 436                 kfree(v9ses->transport);
 437                 v9ses->transport = NULL;
 438         }
 439
 440         __putname(v9ses->name);
 441         __putname(v9ses->remotename);
 442 }
 443
 444 /**
 445  * v9fs_session_cancel - mark transport as disconnected
 446  *      and cancel all pending requests.
 447  */
 448 void v9fs_session_cancel(struct v9fs_session_info *v9ses) {
 449         dprintk(DEBUG_ERROR, "cancel session %p\n", v9ses);
 450         v9ses->transport->status = Disconnected;
 451         v9fs_mux_cancel(v9ses->mux, -EIO);
 452 }
 453
 454 extern int v9fs_error_init(void);
 455
 456 /**
 457  * v9fs_init - Initialize module
 458  *
 459  */
 460
 461 static int __init init_v9fs(void)
 462 {
 463         int ret;
 464
 465         v9fs_error_init();
 466
 467         printk(KERN_INFO "Installing v9fs 9p2000 file system support\n");
 468
 469         ret = v9fs_mux_global_init();
 470         if (ret) {
 471                 printk(KERN_WARNING "v9fs: starting mux failed\n");
 472                 return ret;
 473         }
 474         ret = register_filesystem(&v9fs_fs_type);
 475         if (ret) {
 476                 printk(KERN_WARNING "v9fs: registering file system failed\n");
 477                 v9fs_mux_global_exit();
 478         }
 479
 480         return ret;
 481 }
 482
 483 /**
 484  * v9fs_init - shutdown module
 485  *
 486  */
 487
 488 static void __exit exit_v9fs(void)
 489 {
 490         v9fs_mux_global_exit();
 491         unregister_filesystem(&v9fs_fs_type);
 492 }
 493
 494 module_init(init_v9fs)
 495 module_exit(exit_v9fs)
 496
 497 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
 498 MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
 499 MODULE_LICENSE("GPL");