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) 2004-2008 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 #include <linux/slab.h>
  33 #include <net/9p/9p.h>
  34 #include <net/9p/client.h>
  35 #include <net/9p/transport.h>
  36 #include "v9fs.h"
  37 #include "v9fs_vfs.h"
  38 #include "cache.h"
  39
  40 static DEFINE_SPINLOCK(v9fs_sessionlist_lock);
  41 static LIST_HEAD(v9fs_sessionlist);
  42
  43 /*
  44  * Option Parsing (code inspired by NFS code)
  45  *  NOTE: each transport will parse its own options
  46  */
  47
  48 enum {
  49         /* Options that take integer arguments */
  50         Opt_debug, Opt_dfltuid, Opt_dfltgid, Opt_afid,
  51         /* String options */
  52         Opt_uname, Opt_remotename, Opt_trans, Opt_cache, Opt_cachetag,
  53         /* Options that take no arguments */
  54         Opt_nodevmap,
  55         /* Cache options */
  56         Opt_cache_loose, Opt_fscache,
  57         /* Access options */
  58         Opt_access, Opt_posixacl,
  59         /* Error token */
  60         Opt_err
  61 };
  62
  63 static const match_table_t tokens = {
  64         {Opt_debug, "debug=%x"},
  65         {Opt_dfltuid, "dfltuid=%u"},
  66         {Opt_dfltgid, "dfltgid=%u"},
  67         {Opt_afid, "afid=%u"},
  68         {Opt_uname, "uname=%s"},
  69         {Opt_remotename, "aname=%s"},
  70         {Opt_nodevmap, "nodevmap"},
  71         {Opt_cache, "cache=%s"},
  72         {Opt_cache_loose, "loose"},
  73         {Opt_fscache, "fscache"},
  74         {Opt_cachetag, "cachetag=%s"},
  75         {Opt_access, "access=%s"},
  76         {Opt_posixacl, "posixacl"},
  77         {Opt_err, NULL}
  78 };
  79
  80 /**
  81  * v9fs_parse_options - parse mount options into session structure
  82  * @v9ses: existing v9fs session information
  83  *
  84  * Return 0 upon success, -ERRNO upon failure.
  85  */
  86
  87 static int v9fs_parse_options(struct v9fs_session_info *v9ses, char *opts)
  88 {
  89         char *options, *tmp_options;
  90         substring_t args[MAX_OPT_ARGS];
  91         char *p;
  92         int option = 0;
  93         char *s, *e;
  94         int ret = 0;
  95
  96         /* setup defaults */
  97         v9ses->afid = ~0;
  98         v9ses->debug = 0;
  99         v9ses->cache = 0;
 100 #ifdef CONFIG_9P_FSCACHE
 101         v9ses->cachetag = NULL;
 102 #endif
 103
 104         if (!opts)
 105                 return 0;
 106
 107         tmp_options = kstrdup(opts, GFP_KERNEL);
 108         if (!tmp_options) {
 109                 ret = -ENOMEM;
 110                 goto fail_option_alloc;
 111         }
 112         options = tmp_options;
 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_uname) {
 120                         int r = match_int(&args[0], &option);
 121                         if (r < 0) {
 122                                 P9_DPRINTK(P9_DEBUG_ERROR,
 123                                         "integer field, but no integer?\n");
 124                                 ret = r;
 125                                 continue;
 126                         }
 127                 }
 128                 switch (token) {
 129                 case Opt_debug:
 130                         v9ses->debug = option;
 131 #ifdef CONFIG_NET_9P_DEBUG
 132                         p9_debug_level = option;
 133 #endif
 134                         break;
 135
 136                 case Opt_dfltuid:
 137                         v9ses->dfltuid = option;
 138                         break;
 139                 case Opt_dfltgid:
 140                         v9ses->dfltgid = option;
 141                         break;
 142                 case Opt_afid:
 143                         v9ses->afid = option;
 144                         break;
 145                 case Opt_uname:
 146                         match_strlcpy(v9ses->uname, &args[0], PATH_MAX);
 147                         break;
 148                 case Opt_remotename:
 149                         match_strlcpy(v9ses->aname, &args[0], PATH_MAX);
 150                         break;
 151                 case Opt_nodevmap:
 152                         v9ses->nodev = 1;
 153                         break;
 154                 case Opt_cache_loose:
 155                         v9ses->cache = CACHE_LOOSE;
 156                         break;
 157                 case Opt_fscache:
 158                         v9ses->cache = CACHE_FSCACHE;
 159                         break;
 160                 case Opt_cachetag:
 161 #ifdef CONFIG_9P_FSCACHE
 162                         v9ses->cachetag = match_strdup(&args[0]);
 163 #endif
 164                         break;
 165                 case Opt_cache:
 166                         s = match_strdup(&args[0]);
 167                         if (!s) {
 168                                 ret = -ENOMEM;
 169                                 P9_DPRINTK(P9_DEBUG_ERROR,
 170                                   "problem allocating copy of cache arg\n");
 171                                 goto free_and_return;
 172                         }
 173
 174                         if (strcmp(s, "loose") == 0)
 175                                 v9ses->cache = CACHE_LOOSE;
 176                         else if (strcmp(s, "fscache") == 0)
 177                                 v9ses->cache = CACHE_FSCACHE;
 178                         else
 179                                 v9ses->cache = CACHE_NONE;
 180                         kfree(s);
 181                         break;
 182
 183                 case Opt_access:
 184                         s = match_strdup(&args[0]);
 185                         if (!s) {
 186                                 ret = -ENOMEM;
 187                                 P9_DPRINTK(P9_DEBUG_ERROR,
 188                                   "problem allocating copy of access arg\n");
 189                                 goto free_and_return;
 190                         }
 191
 192                         v9ses->flags &= ~V9FS_ACCESS_MASK;
 193                         if (strcmp(s, "user") == 0)
 194                                 v9ses->flags |= V9FS_ACCESS_USER;
 195                         else if (strcmp(s, "any") == 0)
 196                                 v9ses->flags |= V9FS_ACCESS_ANY;
 197                         else if (strcmp(s, "client") == 0) {
 198                                 v9ses->flags |= V9FS_ACCESS_CLIENT;
 199                         } else {
 200                                 v9ses->flags |= V9FS_ACCESS_SINGLE;
 201                                 v9ses->uid = simple_strtoul(s, &e, 10);
 202                                 if (*e != '\0')
 203                                         v9ses->uid = ~0;
 204                         }
 205                         kfree(s);
 206                         break;
 207
 208                 case Opt_posixacl:
 209 #ifdef CONFIG_9P_FS_POSIX_ACL
 210                         v9ses->flags |= V9FS_POSIX_ACL;
 211 #else
 212                         P9_DPRINTK(P9_DEBUG_ERROR,
 213                                         "Not defined CONFIG_9P_FS_POSIX_ACL. "
 214                                         "Ignoring posixacl option\n");
 215 #endif
 216                         break;
 217
 218                 default:
 219                         continue;
 220                 }
 221         }
 222
 223 free_and_return:
 224         kfree(tmp_options);
 225 fail_option_alloc:
 226         return ret;
 227 }
 228
 229 /**
 230  * v9fs_session_init - initialize session
 231  * @v9ses: session information structure
 232  * @dev_name: device being mounted
 233  * @data: options
 234  *
 235  */
 236
 237 struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
 238                   const char *dev_name, char *data)
 239 {
 240         int retval = -EINVAL;
 241         struct p9_fid *fid;
 242         int rc;
 243
 244         v9ses->uname = __getname();
 245         if (!v9ses->uname)
 246                 return ERR_PTR(-ENOMEM);
 247
 248         v9ses->aname = __getname();
 249         if (!v9ses->aname) {
 250                 __putname(v9ses->uname);
 251                 return ERR_PTR(-ENOMEM);
 252         }
 253         init_rwsem(&v9ses->rename_sem);
 254
 255         rc = bdi_setup_and_register(&v9ses->bdi, "9p", BDI_CAP_MAP_COPY);
 256         if (rc) {
 257                 __putname(v9ses->aname);
 258                 __putname(v9ses->uname);
 259                 return ERR_PTR(rc);
 260         }
 261
 262         spin_lock(&v9fs_sessionlist_lock);
 263         list_add(&v9ses->slist, &v9fs_sessionlist);
 264         spin_unlock(&v9fs_sessionlist_lock);
 265
 266         v9ses->flags = V9FS_ACCESS_USER;
 267         strcpy(v9ses->uname, V9FS_DEFUSER);
 268         strcpy(v9ses->aname, V9FS_DEFANAME);
 269         v9ses->uid = ~0;
 270         v9ses->dfltuid = V9FS_DEFUID;
 271         v9ses->dfltgid = V9FS_DEFGID;
 272
 273         rc = v9fs_parse_options(v9ses, data);
 274         if (rc < 0) {
 275                 retval = rc;
 276                 goto error;
 277         }
 278
 279         v9ses->clnt = p9_client_create(dev_name, data);
 280         if (IS_ERR(v9ses->clnt)) {
 281                 retval = PTR_ERR(v9ses->clnt);
 282                 v9ses->clnt = NULL;
 283                 P9_DPRINTK(P9_DEBUG_ERROR, "problem initializing 9p client\n");
 284                 goto error;
 285         }
 286
 287         if (p9_is_proto_dotl(v9ses->clnt))
 288                 v9ses->flags |= V9FS_PROTO_2000L;
 289         else if (p9_is_proto_dotu(v9ses->clnt))
 290                 v9ses->flags |= V9FS_PROTO_2000U;
 291
 292         v9ses->maxdata = v9ses->clnt->msize - P9_IOHDRSZ;
 293
 294         if (!v9fs_proto_dotl(v9ses) &&
 295             ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
 296                 /*
 297                  * We support ACCESS_CLIENT only for dotl.
 298                  * Fall back to ACCESS_USER
 299                  */
 300                 v9ses->flags &= ~V9FS_ACCESS_MASK;
 301                 v9ses->flags |= V9FS_ACCESS_USER;
 302         }
 303         /*FIXME !! */
 304         /* for legacy mode, fall back to V9FS_ACCESS_ANY */
 305         if (!(v9fs_proto_dotu(v9ses) || v9fs_proto_dotl(v9ses)) &&
 306                 ((v9ses->flags&V9FS_ACCESS_MASK) == V9FS_ACCESS_USER)) {
 307
 308                 v9ses->flags &= ~V9FS_ACCESS_MASK;
 309                 v9ses->flags |= V9FS_ACCESS_ANY;
 310                 v9ses->uid = ~0;
 311         }
 312         if (!v9fs_proto_dotl(v9ses) ||
 313                 !((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
 314                 /*
 315                  * We support ACL checks on clinet only if the protocol is
 316                  * 9P2000.L and access is V9FS_ACCESS_CLIENT.
 317                  */
 318                 v9ses->flags &= ~V9FS_ACL_MASK;
 319         }
 320
 321         fid = p9_client_attach(v9ses->clnt, NULL, v9ses->uname, ~0,
 322                                                         v9ses->aname);
 323         if (IS_ERR(fid)) {
 324                 retval = PTR_ERR(fid);
 325                 fid = NULL;
 326                 P9_DPRINTK(P9_DEBUG_ERROR, "cannot attach\n");
 327                 goto error;
 328         }
 329
 330         if ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_SINGLE)
 331                 fid->uid = v9ses->uid;
 332         else
 333                 fid->uid = ~0;
 334
 335 #ifdef CONFIG_9P_FSCACHE
 336         /* register the session for caching */
 337         v9fs_cache_session_get_cookie(v9ses);
 338 #endif
 339
 340         return fid;
 341
 342 error:
 343         bdi_destroy(&v9ses->bdi);
 344         return ERR_PTR(retval);
 345 }
 346
 347 /**
 348  * v9fs_session_close - shutdown a session
 349  * @v9ses: session information structure
 350  *
 351  */
 352
 353 void v9fs_session_close(struct v9fs_session_info *v9ses)
 354 {
 355         if (v9ses->clnt) {
 356                 p9_client_destroy(v9ses->clnt);
 357                 v9ses->clnt = NULL;
 358         }
 359
 360 #ifdef CONFIG_9P_FSCACHE
 361         if (v9ses->fscache) {
 362                 v9fs_cache_session_put_cookie(v9ses);
 363                 kfree(v9ses->cachetag);
 364         }
 365 #endif
 366         __putname(v9ses->uname);
 367         __putname(v9ses->aname);
 368
 369         bdi_destroy(&v9ses->bdi);
 370
 371         spin_lock(&v9fs_sessionlist_lock);
 372         list_del(&v9ses->slist);
 373         spin_unlock(&v9fs_sessionlist_lock);
 374 }
 375
 376 /**
 377  * v9fs_session_cancel - terminate a session
 378  * @v9ses: session to terminate
 379  *
 380  * mark transport as disconnected and cancel all pending requests.
 381  */
 382
 383 void v9fs_session_cancel(struct v9fs_session_info *v9ses) {
 384         P9_DPRINTK(P9_DEBUG_ERROR, "cancel session %p\n", v9ses);
 385         p9_client_disconnect(v9ses->clnt);
 386 }
 387
 388 /**
 389  * v9fs_session_begin_cancel - Begin terminate of a session
 390  * @v9ses: session to terminate
 391  *
 392  * After this call we don't allow any request other than clunk.
 393  */
 394
 395 void v9fs_session_begin_cancel(struct v9fs_session_info *v9ses)
 396 {
 397         P9_DPRINTK(P9_DEBUG_ERROR, "begin cancel session %p\n", v9ses);
 398         p9_client_begin_disconnect(v9ses->clnt);
 399 }
 400
 401 extern int v9fs_error_init(void);
 402
 403 static struct kobject *v9fs_kobj;
 404
 405 #ifdef CONFIG_9P_FSCACHE
 406 /**
 407  * caches_show - list caches associated with a session
 408  *
 409  * Returns the size of buffer written.
 410  */
 411
 412 static ssize_t caches_show(struct kobject *kobj,
 413                            struct kobj_attribute *attr,
 414                            char *buf)
 415 {
 416         ssize_t n = 0, count = 0, limit = PAGE_SIZE;
 417         struct v9fs_session_info *v9ses;
 418
 419         spin_lock(&v9fs_sessionlist_lock);
 420         list_for_each_entry(v9ses, &v9fs_sessionlist, slist) {
 421                 if (v9ses->cachetag) {
 422                         n = snprintf(buf, limit, "%s\n", v9ses->cachetag);
 423                         if (n < 0) {
 424                                 count = n;
 425                                 break;
 426                         }
 427
 428                         count += n;
 429                         limit -= n;
 430                 }
 431         }
 432
 433         spin_unlock(&v9fs_sessionlist_lock);
 434         return count;
 435 }
 436
 437 static struct kobj_attribute v9fs_attr_cache = __ATTR_RO(caches);
 438 #endif /* CONFIG_9P_FSCACHE */
 439
 440 static struct attribute *v9fs_attrs[] = {
 441 #ifdef CONFIG_9P_FSCACHE
 442         &v9fs_attr_cache.attr,
 443 #endif
 444         NULL,
 445 };
 446
 447 static struct attribute_group v9fs_attr_group = {
 448         .attrs = v9fs_attrs,
 449 };
 450
 451 /**
 452  * v9fs_sysfs_init - Initialize the v9fs sysfs interface
 453  *
 454  */
 455
 456 static int v9fs_sysfs_init(void)
 457 {
 458         v9fs_kobj = kobject_create_and_add("9p", fs_kobj);
 459         if (!v9fs_kobj)
 460                 return -ENOMEM;
 461
 462         if (sysfs_create_group(v9fs_kobj, &v9fs_attr_group)) {
 463                 kobject_put(v9fs_kobj);
 464                 return -ENOMEM;
 465         }
 466
 467         return 0;
 468 }
 469
 470 /**
 471  * v9fs_sysfs_cleanup - Unregister the v9fs sysfs interface
 472  *
 473  */
 474
 475 static void v9fs_sysfs_cleanup(void)
 476 {
 477         sysfs_remove_group(v9fs_kobj, &v9fs_attr_group);
 478         kobject_put(v9fs_kobj);
 479 }
 480
 481 /**
 482  * init_v9fs - Initialize module
 483  *
 484  */
 485
 486 static int __init init_v9fs(void)
 487 {
 488         int err;
 489         printk(KERN_INFO "Installing v9fs 9p2000 file system support\n");
 490         /* TODO: Setup list of registered trasnport modules */
 491         err = register_filesystem(&v9fs_fs_type);
 492         if (err < 0) {
 493                 printk(KERN_ERR "Failed to register filesystem\n");
 494                 return err;
 495         }
 496
 497         err = v9fs_cache_register();
 498         if (err < 0) {
 499                 printk(KERN_ERR "Failed to register v9fs for caching\n");
 500                 goto out_fs_unreg;
 501         }
 502
 503         err = v9fs_sysfs_init();
 504         if (err < 0) {
 505                 printk(KERN_ERR "Failed to register with sysfs\n");
 506                 goto out_sysfs_cleanup;
 507         }
 508
 509         return 0;
 510
 511 out_sysfs_cleanup:
 512         v9fs_sysfs_cleanup();
 513
 514 out_fs_unreg:
 515         unregister_filesystem(&v9fs_fs_type);
 516
 517         return err;
 518 }
 519
 520 /**
 521  * exit_v9fs - shutdown module
 522  *
 523  */
 524
 525 static void __exit exit_v9fs(void)
 526 {
 527         v9fs_sysfs_cleanup();
 528         v9fs_cache_unregister();
 529         unregister_filesystem(&v9fs_fs_type);
 530 }
 531
 532 module_init(init_v9fs)
 533 module_exit(exit_v9fs)
 534
 535 MODULE_AUTHOR("Latchesar Ionkov <lucho@ionkov.net>");
 536 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
 537 MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
 538 MODULE_LICENSE("GPL");