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/parser.h>
  30 #include <linux/idr.h>
  31
  32 #include "debug.h"
  33 #include "v9fs.h"
  34 #include "9p.h"
  35 #include "v9fs_vfs.h"
  36 #include "transport.h"
  37 #include "mux.h"
  38
  39 /* TODO: sysfs or debugfs interface */
  40 int v9fs_debug_level = 0;       /* feature-rific global debug level  */
  41
  42 /*
  43   * Option Parsing (code inspired by NFS code)
  44   *
  45   */
  46
  47 enum {
  48         /* Options that take integer arguments */
  49         Opt_port, Opt_msize, Opt_uid, Opt_gid, Opt_afid, Opt_debug,
  50         Opt_rfdno, Opt_wfdno,
  51         /* String options */
  52         Opt_uname, Opt_remotename,
  53         /* Options that take no arguments */
  54         Opt_legacy, Opt_nodevmap, Opt_unix, Opt_tcp, Opt_fd,
  55         /* Error token */
  56         Opt_err
  57 };
  58
  59 static match_table_t tokens = {
  60         {Opt_port, "port=%u"},
  61         {Opt_msize, "msize=%u"},
  62         {Opt_uid, "uid=%u"},
  63         {Opt_gid, "gid=%u"},
  64         {Opt_afid, "afid=%u"},
  65         {Opt_rfdno, "rfdno=%u"},
  66         {Opt_wfdno, "wfdno=%u"},
  67         {Opt_debug, "debug=%x"},
  68         {Opt_uname, "uname=%s"},
  69         {Opt_remotename, "aname=%s"},
  70         {Opt_unix, "proto=unix"},
  71         {Opt_tcp, "proto=tcp"},
  72         {Opt_fd, "proto=fd"},
  73         {Opt_tcp, "tcp"},
  74         {Opt_unix, "unix"},
  75         {Opt_fd, "fd"},
  76         {Opt_legacy, "noextend"},
  77         {Opt_nodevmap, "nodevmap"},
  78         {Opt_err, NULL}
  79 };
  80
  81 /*
  82  *  Parse option string.
  83  */
  84
  85 /**
  86  * v9fs_parse_options - parse mount options into session structure
  87  * @options: options string passed from mount
  88  * @v9ses: existing v9fs session information
  89  *
  90  */
  91
  92 static void v9fs_parse_options(char *options, struct v9fs_session_info *v9ses)
  93 {
  94         char *p;
  95         substring_t args[MAX_OPT_ARGS];
  96         int option;
  97         int ret;
  98
  99         /* setup defaults */
 100         v9ses->port = V9FS_PORT;
 101         v9ses->maxdata = 9000;
 102         v9ses->proto = PROTO_TCP;
 103         v9ses->extended = 1;
 104         v9ses->afid = ~0;
 105         v9ses->debug = 0;
 106         v9ses->rfdno = ~0;
 107         v9ses->wfdno = ~0;
 108
 109         if (!options)
 110                 return;
 111
 112         while ((p = strsep(&options, ",")) != NULL) {
 113                 int token;
 114                 if (!*p)
 115                         continue;
 116                 token = match_token(p, tokens, args);
 117                 if (token < Opt_uname) {
 118                         if ((ret = match_int(&args[0], &option)) < 0) {
 119                                 dprintk(DEBUG_ERROR,
 120                                         "integer field, but no integer?\n");
 121                                 continue;
 122                         }
 123
 124                 }
 125                 switch (token) {
 126                 case Opt_port:
 127                         v9ses->port = option;
 128                         break;
 129                 case Opt_msize:
 130                         v9ses->maxdata = option;
 131                         break;
 132                 case Opt_uid:
 133                         v9ses->uid = option;
 134                         break;
 135                 case Opt_gid:
 136                         v9ses->gid = option;
 137                         break;
 138                 case Opt_afid:
 139                         v9ses->afid = option;
 140                         break;
 141                 case Opt_rfdno:
 142                         v9ses->rfdno = option;
 143                         break;
 144                 case Opt_wfdno:
 145                         v9ses->wfdno = option;
 146                         break;
 147                 case Opt_debug:
 148                         v9ses->debug = option;
 149                         break;
 150                 case Opt_tcp:
 151                         v9ses->proto = PROTO_TCP;
 152                         break;
 153                 case Opt_unix:
 154                         v9ses->proto = PROTO_UNIX;
 155                         break;
 156                 case Opt_fd:
 157                         v9ses->proto = PROTO_FD;
 158                         break;
 159                 case Opt_uname:
 160                         match_strcpy(v9ses->name, &args[0]);
 161                         break;
 162                 case Opt_remotename:
 163                         match_strcpy(v9ses->remotename, &args[0]);
 164                         break;
 165                 case Opt_legacy:
 166                         v9ses->extended = 0;
 167                         break;
 168                 case Opt_nodevmap:
 169                         v9ses->nodev = 1;
 170                         break;
 171                 default:
 172                         continue;
 173                 }
 174         }
 175 }
 176
 177 /**
 178  * v9fs_inode2v9ses - safely extract v9fs session info from super block
 179  * @inode: inode to extract information from
 180  *
 181  * Paranoid function to extract v9ses information from superblock,
 182  * if anything is missing it will report an error.
 183  *
 184  */
 185
 186 struct v9fs_session_info *v9fs_inode2v9ses(struct inode *inode)
 187 {
 188         return (inode->i_sb->s_fs_info);
 189 }
 190
 191 /**
 192  * v9fs_get_idpool - allocate numeric id from pool
 193  * @p - pool to allocate from
 194  *
 195  * XXX - This seems to be an awful generic function, should it be in idr.c with
 196  *            the lock included in struct idr?
 197  */
 198
 199 int v9fs_get_idpool(struct v9fs_idpool *p)
 200 {
 201         int i = 0;
 202         int error;
 203
 204 retry:
 205         if (idr_pre_get(&p->pool, GFP_KERNEL) == 0)
 206                 return 0;
 207
 208         if (down_interruptible(&p->lock) == -EINTR) {
 209                 eprintk(KERN_WARNING, "Interrupted while locking\n");
 210                 return -1;
 211         }
 212
 213         /* no need to store exactly p, we just need something non-null */
 214         error = idr_get_new(&p->pool, p, &i);
 215         up(&p->lock);
 216
 217         if (error == -EAGAIN)
 218                 goto retry;
 219         else if (error)
 220                 return -1;
 221
 222         return i;
 223 }
 224
 225 /**
 226  * v9fs_put_idpool - release numeric id from pool
 227  * @p - pool to allocate from
 228  *
 229  * XXX - This seems to be an awful generic function, should it be in idr.c with
 230  *            the lock included in struct idr?
 231  */
 232
 233 void v9fs_put_idpool(int id, struct v9fs_idpool *p)
 234 {
 235         if (down_interruptible(&p->lock) == -EINTR) {
 236                 eprintk(KERN_WARNING, "Interrupted while locking\n");
 237                 return;
 238         }
 239         idr_remove(&p->pool, id);
 240         up(&p->lock);
 241 }
 242
 243 /**
 244  * v9fs_check_idpool - check if the specified id is available
 245  * @id - id to check
 246  * @p - pool
 247  */
 248 int v9fs_check_idpool(int id, struct v9fs_idpool *p)
 249 {
 250         return idr_find(&p->pool, id) != NULL;
 251 }
 252
 253 /**
 254  * v9fs_session_init - initialize session
 255  * @v9ses: session information structure
 256  * @dev_name: device being mounted
 257  * @data: options
 258  *
 259  */
 260
 261 int
 262 v9fs_session_init(struct v9fs_session_info *v9ses,
 263                   const char *dev_name, char *data)
 264 {
 265         struct v9fs_fcall *fcall = NULL;
 266         struct v9fs_transport *trans_proto;
 267         int n = 0;
 268         int newfid = -1;
 269         int retval = -EINVAL;
 270         struct v9fs_str *version;
 271
 272         v9ses->name = __getname();
 273         if (!v9ses->name)
 274                 return -ENOMEM;
 275
 276         v9ses->remotename = __getname();
 277         if (!v9ses->remotename) {
 278                 __putname(v9ses->name);
 279                 return -ENOMEM;
 280         }
 281
 282         strcpy(v9ses->name, V9FS_DEFUSER);
 283         strcpy(v9ses->remotename, V9FS_DEFANAME);
 284
 285         v9fs_parse_options(data, v9ses);
 286
 287         /* set global debug level */
 288         v9fs_debug_level = v9ses->debug;
 289
 290         /* id pools that are session-dependent: fids and tags */
 291         idr_init(&v9ses->fidpool.pool);
 292         init_MUTEX(&v9ses->fidpool.lock);
 293
 294         switch (v9ses->proto) {
 295         case PROTO_TCP:
 296                 trans_proto = &v9fs_trans_tcp;
 297                 break;
 298         case PROTO_UNIX:
 299                 trans_proto = &v9fs_trans_unix;
 300                 *v9ses->remotename = 0;
 301                 break;
 302         case PROTO_FD:
 303                 trans_proto = &v9fs_trans_fd;
 304                 *v9ses->remotename = 0;
 305                 break;
 306         default:
 307                 printk(KERN_ERR "v9fs: Bad mount protocol %d\n", v9ses->proto);
 308                 retval = -ENOPROTOOPT;
 309                 goto SessCleanUp;
 310         };
 311
 312         v9ses->transport = kmalloc(sizeof(*v9ses->transport), GFP_KERNEL);
 313         if (!v9ses->transport) {
 314                 retval = -ENOMEM;
 315                 goto SessCleanUp;
 316         }
 317
 318         memmove(v9ses->transport, trans_proto, sizeof(*v9ses->transport));
 319
 320         if ((retval = v9ses->transport->init(v9ses, dev_name, data)) < 0) {
 321                 eprintk(KERN_ERR, "problem initializing transport\n");
 322                 goto SessCleanUp;
 323         }
 324
 325         v9ses->inprogress = 0;
 326         v9ses->shutdown = 0;
 327         v9ses->session_hung = 0;
 328
 329         v9ses->mux = v9fs_mux_init(v9ses->transport, v9ses->maxdata + V9FS_IOHDRSZ,
 330                 &v9ses->extended);
 331
 332         if (IS_ERR(v9ses->mux)) {
 333                 retval = PTR_ERR(v9ses->mux);
 334                 v9ses->mux = NULL;
 335                 dprintk(DEBUG_ERROR, "problem initializing mux\n");
 336                 goto SessCleanUp;
 337         }
 338
 339         if (v9ses->afid == ~0) {
 340                 if (v9ses->extended)
 341                         retval =
 342                             v9fs_t_version(v9ses, v9ses->maxdata, "9P2000.u",
 343                                            &fcall);
 344                 else
 345                         retval = v9fs_t_version(v9ses, v9ses->maxdata, "9P2000",
 346                                                 &fcall);
 347
 348                 if (retval < 0) {
 349                         dprintk(DEBUG_ERROR, "v9fs_t_version failed\n");
 350                         goto FreeFcall;
 351                 }
 352
 353                 version = &fcall->params.rversion.version;
 354                 if (version->len==8 && !memcmp(version->str, "9P2000.u", 8)) {
 355                         dprintk(DEBUG_9P, "9P2000 UNIX extensions enabled\n");
 356                         v9ses->extended = 1;
 357                 } else if (version->len==6 && !memcmp(version->str, "9P2000", 6)) {
 358                         dprintk(DEBUG_9P, "9P2000 legacy mode enabled\n");
 359                         v9ses->extended = 0;
 360                 } else {
 361                         retval = -EREMOTEIO;
 362                         goto FreeFcall;
 363                 }
 364
 365                 n = fcall->params.rversion.msize;
 366                 kfree(fcall);
 367
 368                 if (n < v9ses->maxdata)
 369                         v9ses->maxdata = n;
 370         }
 371
 372         newfid = v9fs_get_idpool(&v9ses->fidpool);
 373         if (newfid < 0) {
 374                 eprintk(KERN_WARNING, "couldn't allocate FID\n");
 375                 retval = -ENOMEM;
 376                 goto SessCleanUp;
 377         }
 378         /* it is a little bit ugly, but we have to prevent newfid */
 379         /* being the same as afid, so if it is, get a new fid     */
 380         if (v9ses->afid != ~0 && newfid == v9ses->afid) {
 381                 newfid = v9fs_get_idpool(&v9ses->fidpool);
 382                 if (newfid < 0) {
 383                         eprintk(KERN_WARNING, "couldn't allocate FID\n");
 384                         retval = -ENOMEM;
 385                         goto SessCleanUp;
 386                 }
 387         }
 388
 389         if ((retval =
 390              v9fs_t_attach(v9ses, v9ses->name, v9ses->remotename, newfid,
 391                            v9ses->afid, NULL))
 392             < 0) {
 393                 dprintk(DEBUG_ERROR, "cannot attach\n");
 394                 goto SessCleanUp;
 395         }
 396
 397         if (v9ses->afid != ~0) {
 398                 dprintk(DEBUG_ERROR, "afid not equal to ~0\n");
 399                 if (v9fs_t_clunk(v9ses, v9ses->afid))
 400                         dprintk(DEBUG_ERROR, "clunk failed\n");
 401         }
 402
 403         return newfid;
 404
 405       FreeFcall:
 406         kfree(fcall);
 407
 408       SessCleanUp:
 409         v9fs_session_close(v9ses);
 410         return retval;
 411 }
 412
 413 /**
 414  * v9fs_session_close - shutdown a session
 415  * @v9ses: session information structure
 416  *
 417  */
 418
 419 void v9fs_session_close(struct v9fs_session_info *v9ses)
 420 {
 421         if (v9ses->mux) {
 422                 v9fs_mux_destroy(v9ses->mux);
 423                 v9ses->mux = NULL;
 424         }
 425
 426         if (v9ses->transport) {
 427                 v9ses->transport->close(v9ses->transport);
 428                 kfree(v9ses->transport);
 429                 v9ses->transport = NULL;
 430         }
 431
 432         __putname(v9ses->name);
 433         __putname(v9ses->remotename);
 434 }
 435
 436 /**
 437  * v9fs_session_cancel - mark transport as disconnected
 438  *      and cancel all pending requests.
 439  */
 440 void v9fs_session_cancel(struct v9fs_session_info *v9ses) {
 441         dprintk(DEBUG_ERROR, "cancel session %p\n", v9ses);
 442         v9ses->transport->status = Disconnected;
 443         v9fs_mux_cancel(v9ses->mux, -EIO);
 444 }
 445
 446 extern int v9fs_error_init(void);
 447
 448 /**
 449  * v9fs_init - Initialize module
 450  *
 451  */
 452
 453 static int __init init_v9fs(void)
 454 {
 455         int ret;
 456
 457         v9fs_error_init();
 458
 459         printk(KERN_INFO "Installing v9fs 9P2000 file system support\n");
 460
 461         ret = v9fs_mux_global_init();
 462         if (!ret)
 463                 ret = register_filesystem(&v9fs_fs_type);
 464
 465         return ret;
 466 }
 467
 468 /**
 469  * v9fs_init - shutdown module
 470  *
 471  */
 472
 473 static void __exit exit_v9fs(void)
 474 {
 475         v9fs_mux_global_exit();
 476         unregister_filesystem(&v9fs_fs_type);
 477 }
 478
 479 module_init(init_v9fs)
 480 module_exit(exit_v9fs)
 481
 482 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
 483 MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
 484 MODULE_LICENSE("GPL");