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         /* Error token */
  57         Opt_err
  58 };
  59
  60 static match_table_t tokens = {
  61         {Opt_port, "port=%u"},
  62         {Opt_msize, "msize=%u"},
  63         {Opt_uid, "uid=%u"},
  64         {Opt_gid, "gid=%u"},
  65         {Opt_afid, "afid=%u"},
  66         {Opt_rfdno, "rfdno=%u"},
  67         {Opt_wfdno, "wfdno=%u"},
  68         {Opt_debug, "debug=%x"},
  69         {Opt_uname, "uname=%s"},
  70         {Opt_remotename, "aname=%s"},
  71         {Opt_unix, "proto=unix"},
  72         {Opt_tcp, "proto=tcp"},
  73         {Opt_fd, "proto=fd"},
  74         {Opt_tcp, "tcp"},
  75         {Opt_unix, "unix"},
  76         {Opt_fd, "fd"},
  77         {Opt_legacy, "noextend"},
  78         {Opt_nodevmap, "nodevmap"},
  79         {Opt_err, NULL}
  80 };
  81
  82 /*
  83  *  Parse option string.
  84  */
  85
  86 /**
  87  * v9fs_parse_options - parse mount options into session structure
  88  * @options: options string passed from mount
  89  * @v9ses: existing v9fs session information
  90  *
  91  */
  92
  93 static void v9fs_parse_options(char *options, struct v9fs_session_info *v9ses)
  94 {
  95         char *p;
  96         substring_t args[MAX_OPT_ARGS];
  97         int option;
  98         int ret;
  99
 100         /* setup defaults */
 101         v9ses->port = V9FS_PORT;
 102         v9ses->maxdata = 9000;
 103         v9ses->proto = PROTO_TCP;
 104         v9ses->extended = 1;
 105         v9ses->afid = ~0;
 106         v9ses->debug = 0;
 107         v9ses->rfdno = ~0;
 108         v9ses->wfdno = ~0;
 109
 110         if (!options)
 111                 return;
 112
 113         while ((p = strsep(&options, ",")) != NULL) {
 114                 int token;
 115                 if (!*p)
 116                         continue;
 117                 token = match_token(p, tokens, args);
 118                 if (token < Opt_uname) {
 119                         if ((ret = match_int(&args[0], &option)) < 0) {
 120                                 dprintk(DEBUG_ERROR,
 121                                         "integer field, but no integer?\n");
 122                                 continue;
 123                         }
 124
 125                 }
 126                 switch (token) {
 127                 case Opt_port:
 128                         v9ses->port = option;
 129                         break;
 130                 case Opt_msize:
 131                         v9ses->maxdata = option;
 132                         break;
 133                 case Opt_uid:
 134                         v9ses->uid = option;
 135                         break;
 136                 case Opt_gid:
 137                         v9ses->gid = option;
 138                         break;
 139                 case Opt_afid:
 140                         v9ses->afid = option;
 141                         break;
 142                 case Opt_rfdno:
 143                         v9ses->rfdno = option;
 144                         break;
 145                 case Opt_wfdno:
 146                         v9ses->wfdno = option;
 147                         break;
 148                 case Opt_debug:
 149                         v9ses->debug = option;
 150                         break;
 151                 case Opt_tcp:
 152                         v9ses->proto = PROTO_TCP;
 153                         break;
 154                 case Opt_unix:
 155                         v9ses->proto = PROTO_UNIX;
 156                         break;
 157                 case Opt_fd:
 158                         v9ses->proto = PROTO_FD;
 159                         break;
 160                 case Opt_uname:
 161                         match_strcpy(v9ses->name, &args[0]);
 162                         break;
 163                 case Opt_remotename:
 164                         match_strcpy(v9ses->remotename, &args[0]);
 165                         break;
 166                 case Opt_legacy:
 167                         v9ses->extended = 0;
 168                         break;
 169                 case Opt_nodevmap:
 170                         v9ses->nodev = 1;
 171                         break;
 172                 default:
 173                         continue;
 174                 }
 175         }
 176 }
 177
 178 /**
 179  * v9fs_inode2v9ses - safely extract v9fs session info from super block
 180  * @inode: inode to extract information from
 181  *
 182  * Paranoid function to extract v9ses information from superblock,
 183  * if anything is missing it will report an error.
 184  *
 185  */
 186
 187 struct v9fs_session_info *v9fs_inode2v9ses(struct inode *inode)
 188 {
 189         return (inode->i_sb->s_fs_info);
 190 }
 191
 192 /**
 193  * v9fs_get_idpool - allocate numeric id from pool
 194  * @p - pool to allocate from
 195  *
 196  * XXX - This seems to be an awful generic function, should it be in idr.c with
 197  *            the lock included in struct idr?
 198  */
 199
 200 int v9fs_get_idpool(struct v9fs_idpool *p)
 201 {
 202         int i = 0;
 203         int error;
 204
 205 retry:
 206         if (idr_pre_get(&p->pool, GFP_KERNEL) == 0)
 207                 return 0;
 208
 209         if (down_interruptible(&p->lock) == -EINTR) {
 210                 eprintk(KERN_WARNING, "Interrupted while locking\n");
 211                 return -1;
 212         }
 213
 214         /* no need to store exactly p, we just need something non-null */
 215         error = idr_get_new(&p->pool, p, &i);
 216         up(&p->lock);
 217
 218         if (error == -EAGAIN)
 219                 goto retry;
 220         else if (error)
 221                 return -1;
 222
 223         return i;
 224 }
 225
 226 /**
 227  * v9fs_put_idpool - release numeric id from pool
 228  * @p - pool to allocate from
 229  *
 230  * XXX - This seems to be an awful generic function, should it be in idr.c with
 231  *            the lock included in struct idr?
 232  */
 233
 234 void v9fs_put_idpool(int id, struct v9fs_idpool *p)
 235 {
 236         if (down_interruptible(&p->lock) == -EINTR) {
 237                 eprintk(KERN_WARNING, "Interrupted while locking\n");
 238                 return;
 239         }
 240         idr_remove(&p->pool, id);
 241         up(&p->lock);
 242 }
 243
 244 /**
 245  * v9fs_check_idpool - check if the specified id is available
 246  * @id - id to check
 247  * @p - pool
 248  */
 249 int v9fs_check_idpool(int id, struct v9fs_idpool *p)
 250 {
 251         return idr_find(&p->pool, id) != NULL;
 252 }
 253
 254 /**
 255  * v9fs_session_init - initialize session
 256  * @v9ses: session information structure
 257  * @dev_name: device being mounted
 258  * @data: options
 259  *
 260  */
 261
 262 int
 263 v9fs_session_init(struct v9fs_session_info *v9ses,
 264                   const char *dev_name, char *data)
 265 {
 266         struct v9fs_fcall *fcall = NULL;
 267         struct v9fs_transport *trans_proto;
 268         int n = 0;
 269         int newfid = -1;
 270         int retval = -EINVAL;
 271         struct v9fs_str *version;
 272
 273         v9ses->name = __getname();
 274         if (!v9ses->name)
 275                 return -ENOMEM;
 276
 277         v9ses->remotename = __getname();
 278         if (!v9ses->remotename) {
 279                 __putname(v9ses->name);
 280                 return -ENOMEM;
 281         }
 282
 283         strcpy(v9ses->name, V9FS_DEFUSER);
 284         strcpy(v9ses->remotename, V9FS_DEFANAME);
 285
 286         v9fs_parse_options(data, v9ses);
 287
 288         /* set global debug level */
 289         v9fs_debug_level = v9ses->debug;
 290
 291         /* id pools that are session-dependent: fids and tags */
 292         idr_init(&v9ses->fidpool.pool);
 293         init_MUTEX(&v9ses->fidpool.lock);
 294
 295         switch (v9ses->proto) {
 296         case PROTO_TCP:
 297                 trans_proto = &v9fs_trans_tcp;
 298                 break;
 299         case PROTO_UNIX:
 300                 trans_proto = &v9fs_trans_unix;
 301                 *v9ses->remotename = 0;
 302                 break;
 303         case PROTO_FD:
 304                 trans_proto = &v9fs_trans_fd;
 305                 *v9ses->remotename = 0;
 306                 break;
 307         default:
 308                 printk(KERN_ERR "v9fs: Bad mount protocol %d\n", v9ses->proto);
 309                 retval = -ENOPROTOOPT;
 310                 goto SessCleanUp;
 311         };
 312
 313         v9ses->transport = kmalloc(sizeof(*v9ses->transport), GFP_KERNEL);
 314         if (!v9ses->transport) {
 315                 retval = -ENOMEM;
 316                 goto SessCleanUp;
 317         }
 318
 319         memmove(v9ses->transport, trans_proto, sizeof(*v9ses->transport));
 320
 321         if ((retval = v9ses->transport->init(v9ses, dev_name, data)) < 0) {
 322                 eprintk(KERN_ERR, "problem initializing transport\n");
 323                 goto SessCleanUp;
 324         }
 325
 326         v9ses->inprogress = 0;
 327         v9ses->shutdown = 0;
 328         v9ses->session_hung = 0;
 329
 330         v9ses->mux = v9fs_mux_init(v9ses->transport, v9ses->maxdata + V9FS_IOHDRSZ,
 331                 &v9ses->extended);
 332
 333         if (IS_ERR(v9ses->mux)) {
 334                 retval = PTR_ERR(v9ses->mux);
 335                 v9ses->mux = NULL;
 336                 dprintk(DEBUG_ERROR, "problem initializing mux\n");
 337                 goto SessCleanUp;
 338         }
 339
 340         if (v9ses->afid == ~0) {
 341                 if (v9ses->extended)
 342                         retval =
 343                             v9fs_t_version(v9ses, v9ses->maxdata, "9P2000.u",
 344                                            &fcall);
 345                 else
 346                         retval = v9fs_t_version(v9ses, v9ses->maxdata, "9P2000",
 347                                                 &fcall);
 348
 349                 if (retval < 0) {
 350                         dprintk(DEBUG_ERROR, "v9fs_t_version failed\n");
 351                         goto FreeFcall;
 352                 }
 353
 354                 version = &fcall->params.rversion.version;
 355                 if (version->len==8 && !memcmp(version->str, "9P2000.u", 8)) {
 356                         dprintk(DEBUG_9P, "9P2000 UNIX extensions enabled\n");
 357                         v9ses->extended = 1;
 358                 } else if (version->len==6 && !memcmp(version->str, "9P2000", 6)) {
 359                         dprintk(DEBUG_9P, "9P2000 legacy mode enabled\n");
 360                         v9ses->extended = 0;
 361                 } else {
 362                         retval = -EREMOTEIO;
 363                         goto FreeFcall;
 364                 }
 365
 366                 n = fcall->params.rversion.msize;
 367                 kfree(fcall);
 368
 369                 if (n < v9ses->maxdata)
 370                         v9ses->maxdata = n;
 371         }
 372
 373         newfid = v9fs_get_idpool(&v9ses->fidpool);
 374         if (newfid < 0) {
 375                 eprintk(KERN_WARNING, "couldn't allocate FID\n");
 376                 retval = -ENOMEM;
 377                 goto SessCleanUp;
 378         }
 379         /* it is a little bit ugly, but we have to prevent newfid */
 380         /* being the same as afid, so if it is, get a new fid     */
 381         if (v9ses->afid != ~0 && newfid == v9ses->afid) {
 382                 newfid = v9fs_get_idpool(&v9ses->fidpool);
 383                 if (newfid < 0) {
 384                         eprintk(KERN_WARNING, "couldn't allocate FID\n");
 385                         retval = -ENOMEM;
 386                         goto SessCleanUp;
 387                 }
 388         }
 389
 390         if ((retval =
 391              v9fs_t_attach(v9ses, v9ses->name, v9ses->remotename, newfid,
 392                            v9ses->afid, NULL))
 393             < 0) {
 394                 dprintk(DEBUG_ERROR, "cannot attach\n");
 395                 goto SessCleanUp;
 396         }
 397
 398         if (v9ses->afid != ~0) {
 399                 dprintk(DEBUG_ERROR, "afid not equal to ~0\n");
 400                 if (v9fs_t_clunk(v9ses, v9ses->afid))
 401                         dprintk(DEBUG_ERROR, "clunk failed\n");
 402         }
 403
 404         return newfid;
 405
 406       FreeFcall:
 407         kfree(fcall);
 408
 409       SessCleanUp:
 410         v9fs_session_close(v9ses);
 411         return retval;
 412 }
 413
 414 /**
 415  * v9fs_session_close - shutdown a session
 416  * @v9ses: session information structure
 417  *
 418  */
 419
 420 void v9fs_session_close(struct v9fs_session_info *v9ses)
 421 {
 422         if (v9ses->mux) {
 423                 v9fs_mux_destroy(v9ses->mux);
 424                 v9ses->mux = NULL;
 425         }
 426
 427         if (v9ses->transport) {
 428                 v9ses->transport->close(v9ses->transport);
 429                 kfree(v9ses->transport);
 430                 v9ses->transport = NULL;
 431         }
 432
 433         __putname(v9ses->name);
 434         __putname(v9ses->remotename);
 435 }
 436
 437 /**
 438  * v9fs_session_cancel - mark transport as disconnected
 439  *      and cancel all pending requests.
 440  */
 441 void v9fs_session_cancel(struct v9fs_session_info *v9ses) {
 442         dprintk(DEBUG_ERROR, "cancel session %p\n", v9ses);
 443         v9ses->transport->status = Disconnected;
 444         v9fs_mux_cancel(v9ses->mux, -EIO);
 445 }
 446
 447 extern int v9fs_error_init(void);
 448
 449 /**
 450  * v9fs_init - Initialize module
 451  *
 452  */
 453
 454 static int __init init_v9fs(void)
 455 {
 456         int ret;
 457
 458         v9fs_error_init();
 459
 460         printk(KERN_INFO "Installing v9fs 9P2000 file system support\n");
 461
 462         ret = v9fs_mux_global_init();
 463         if (!ret)
 464                 return ret;
 465         ret = register_filesystem(&v9fs_fs_type);
 466         if (!ret)
 467                 v9fs_mux_global_exit();
 468         return ret;
 469 }
 470
 471 /**
 472  * v9fs_init - shutdown module
 473  *
 474  */
 475
 476 static void __exit exit_v9fs(void)
 477 {
 478         v9fs_mux_global_exit();
 479         unregister_filesystem(&v9fs_fs_type);
 480 }
 481
 482 module_init(init_v9fs)
 483 module_exit(exit_v9fs)
 484
 485 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
 486 MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
 487 MODULE_LICENSE("GPL");