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 struct kmem_cache *v9fs_inode_cache;
  43
  44 /*
  45  * Option Parsing (code inspired by NFS code)
  46  *  NOTE: each transport will parse its own options
  47  */
  48
  49 enum {
  50         /* Options that take integer arguments */
  51         Opt_debug, Opt_dfltuid, Opt_dfltgid, Opt_afid,
  52         /* String options */
  53         Opt_uname, Opt_remotename, Opt_trans, Opt_cache, Opt_cachetag,
  54         /* Options that take no arguments */
  55         Opt_nodevmap,
  56         /* Cache options */
  57         Opt_cache_loose, Opt_fscache,
  58         /* Access options */
  59         Opt_access, Opt_posixacl,
  60         /* Error token */
  61         Opt_err
  62 };
  63
  64 static const match_table_t tokens = {
  65         {Opt_debug, "debug=%x"},
  66         {Opt_dfltuid, "dfltuid=%u"},
  67         {Opt_dfltgid, "dfltgid=%u"},
  68         {Opt_afid, "afid=%u"},
  69         {Opt_uname, "uname=%s"},
  70         {Opt_remotename, "aname=%s"},
  71         {Opt_nodevmap, "nodevmap"},
  72         {Opt_cache, "cache=%s"},
  73         {Opt_cache_loose, "loose"},
  74         {Opt_fscache, "fscache"},
  75         {Opt_cachetag, "cachetag=%s"},
  76         {Opt_access, "access=%s"},
  77         {Opt_posixacl, "posixacl"},
  78         {Opt_err, NULL}
  79 };
  80
  81 /**
  82  * v9fs_parse_options - parse mount options into session structure
  83  * @v9ses: existing v9fs session information
  84  *
  85  * Return 0 upon success, -ERRNO upon failure.
  86  */
  87
  88 static int v9fs_parse_options(struct v9fs_session_info *v9ses, char *opts)
  89 {
  90         char *options, *tmp_options;
  91         substring_t args[MAX_OPT_ARGS];
  92         char *p;
  93         int option = 0;
  94         char *s, *e;
  95         int ret = 0;
  96
  97         /* setup defaults */
  98         v9ses->afid = ~0;
  99         v9ses->debug = 0;
 100         v9ses->cache = 0;
 101 #ifdef CONFIG_9P_FSCACHE
 102         v9ses->cachetag = NULL;
 103 #endif
 104
 105         if (!opts)
 106                 return 0;
 107
 108         tmp_options = kstrdup(opts, GFP_KERNEL);
 109         if (!tmp_options) {
 110                 ret = -ENOMEM;
 111                 goto fail_option_alloc;
 112         }
 113         options = tmp_options;
 114
 115         while ((p = strsep(&options, ",")) != NULL) {
 116                 int token;
 117                 if (!*p)
 118                         continue;
 119                 token = match_token(p, tokens, args);
 120                 if (token < Opt_uname) {
 121                         int r = match_int(&args[0], &option);
 122                         if (r < 0) {
 123                                 P9_DPRINTK(P9_DEBUG_ERROR,
 124                                         "integer field, but no integer?\n");
 125                                 ret = r;
 126                                 continue;
 127                         }
 128                 }
 129                 switch (token) {
 130                 case Opt_debug:
 131                         v9ses->debug = option;
 132 #ifdef CONFIG_NET_9P_DEBUG
 133                         p9_debug_level = option;
 134 #endif
 135                         break;
 136
 137                 case Opt_dfltuid:
 138                         v9ses->dfltuid = option;
 139                         break;
 140                 case Opt_dfltgid:
 141                         v9ses->dfltgid = option;
 142                         break;
 143                 case Opt_afid:
 144                         v9ses->afid = option;
 145                         break;
 146                 case Opt_uname:
 147                         match_strlcpy(v9ses->uname, &args[0], PATH_MAX);
 148                         break;
 149                 case Opt_remotename:
 150                         match_strlcpy(v9ses->aname, &args[0], PATH_MAX);
 151                         break;
 152                 case Opt_nodevmap:
 153                         v9ses->nodev = 1;
 154                         break;
 155                 case Opt_cache_loose:
 156                         v9ses->cache = CACHE_LOOSE;
 157                         break;
 158                 case Opt_fscache:
 159                         v9ses->cache = CACHE_FSCACHE;
 160                         break;
 161                 case Opt_cachetag:
 162 #ifdef CONFIG_9P_FSCACHE
 163                         v9ses->cachetag = match_strdup(&args[0]);
 164 #endif
 165                         break;
 166                 case Opt_cache:
 167                         s = match_strdup(&args[0]);
 168                         if (!s) {
 169                                 ret = -ENOMEM;
 170                                 P9_DPRINTK(P9_DEBUG_ERROR,
 171                                   "problem allocating copy of cache arg\n");
 172                                 goto free_and_return;
 173                         }
 174
 175                         if (strcmp(s, "loose") == 0)
 176                                 v9ses->cache = CACHE_LOOSE;
 177                         else if (strcmp(s, "fscache") == 0)
 178                                 v9ses->cache = CACHE_FSCACHE;
 179                         else
 180                                 v9ses->cache = CACHE_NONE;
 181                         kfree(s);
 182                         break;
 183
 184                 case Opt_access:
 185                         s = match_strdup(&args[0]);
 186                         if (!s) {
 187                                 ret = -ENOMEM;
 188                                 P9_DPRINTK(P9_DEBUG_ERROR,
 189                                   "problem allocating copy of access arg\n");
 190                                 goto free_and_return;
 191                         }
 192
 193                         v9ses->flags &= ~V9FS_ACCESS_MASK;
 194                         if (strcmp(s, "user") == 0)
 195                                 v9ses->flags |= V9FS_ACCESS_USER;
 196                         else if (strcmp(s, "any") == 0)
 197                                 v9ses->flags |= V9FS_ACCESS_ANY;
 198                         else if (strcmp(s, "client") == 0) {
 199                                 v9ses->flags |= V9FS_ACCESS_CLIENT;
 200                         } else {
 201                                 v9ses->flags |= V9FS_ACCESS_SINGLE;
 202                                 v9ses->uid = simple_strtoul(s, &e, 10);
 203                                 if (*e != '\0')
 204                                         v9ses->uid = ~0;
 205                         }
 206                         kfree(s);
 207                         break;
 208
 209                 case Opt_posixacl:
 210 #ifdef CONFIG_9P_FS_POSIX_ACL
 211                         v9ses->flags |= V9FS_POSIX_ACL;
 212 #else
 213                         P9_DPRINTK(P9_DEBUG_ERROR,
 214                                         "Not defined CONFIG_9P_FS_POSIX_ACL. "
 215                                         "Ignoring posixacl option\n");
 216 #endif
 217                         break;
 218
 219                 default:
 220                         continue;
 221                 }
 222         }
 223
 224 free_and_return:
 225         kfree(tmp_options);
 226 fail_option_alloc:
 227         return ret;
 228 }
 229
 230 /**
 231  * v9fs_session_init - initialize session
 232  * @v9ses: session information structure
 233  * @dev_name: device being mounted
 234  * @data: options
 235  *
 236  */
 237
 238 struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
 239                   const char *dev_name, char *data)
 240 {
 241         int retval = -EINVAL;
 242         struct p9_fid *fid;
 243         int rc;
 244
 245         v9ses->uname = __getname();
 246         if (!v9ses->uname)
 247                 return ERR_PTR(-ENOMEM);
 248
 249         v9ses->aname = __getname();
 250         if (!v9ses->aname) {
 251                 __putname(v9ses->uname);
 252                 return ERR_PTR(-ENOMEM);
 253         }
 254         init_rwsem(&v9ses->rename_sem);
 255
 256         rc = bdi_setup_and_register(&v9ses->bdi, "9p", BDI_CAP_MAP_COPY);
 257         if (rc) {
 258                 __putname(v9ses->aname);
 259                 __putname(v9ses->uname);
 260                 return ERR_PTR(rc);
 261         }
 262
 263         spin_lock(&v9fs_sessionlist_lock);
 264         list_add(&v9ses->slist, &v9fs_sessionlist);
 265         spin_unlock(&v9fs_sessionlist_lock);
 266
 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         v9ses->clnt = p9_client_create(dev_name, data);
 274         if (IS_ERR(v9ses->clnt)) {
 275                 retval = PTR_ERR(v9ses->clnt);
 276                 v9ses->clnt = NULL;
 277                 P9_DPRINTK(P9_DEBUG_ERROR, "problem initializing 9p client\n");
 278                 goto error;
 279         }
 280
 281         v9ses->flags = V9FS_ACCESS_USER;
 282
 283         if (p9_is_proto_dotl(v9ses->clnt)) {
 284                 v9ses->flags = V9FS_ACCESS_CLIENT;
 285                 v9ses->flags |= V9FS_PROTO_2000L;
 286         } else if (p9_is_proto_dotu(v9ses->clnt)) {
 287                 v9ses->flags |= V9FS_PROTO_2000U;
 288         }
 289
 290         rc = v9fs_parse_options(v9ses, data);
 291         if (rc < 0) {
 292                 retval = rc;
 293                 goto error;
 294         }
 295
 296         v9ses->maxdata = v9ses->clnt->msize - P9_IOHDRSZ;
 297
 298         if (!v9fs_proto_dotl(v9ses) &&
 299             ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
 300                 /*
 301                  * We support ACCESS_CLIENT only for dotl.
 302                  * Fall back to ACCESS_USER
 303                  */
 304                 v9ses->flags &= ~V9FS_ACCESS_MASK;
 305                 v9ses->flags |= V9FS_ACCESS_USER;
 306         }
 307         /*FIXME !! */
 308         /* for legacy mode, fall back to V9FS_ACCESS_ANY */
 309         if (!(v9fs_proto_dotu(v9ses) || v9fs_proto_dotl(v9ses)) &&
 310                 ((v9ses->flags&V9FS_ACCESS_MASK) == V9FS_ACCESS_USER)) {
 311
 312                 v9ses->flags &= ~V9FS_ACCESS_MASK;
 313                 v9ses->flags |= V9FS_ACCESS_ANY;
 314                 v9ses->uid = ~0;
 315         }
 316         if (!v9fs_proto_dotl(v9ses) ||
 317                 !((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
 318                 /*
 319                  * We support ACL checks on clinet only if the protocol is
 320                  * 9P2000.L and access is V9FS_ACCESS_CLIENT.
 321                  */
 322                 v9ses->flags &= ~V9FS_ACL_MASK;
 323         }
 324
 325         fid = p9_client_attach(v9ses->clnt, NULL, v9ses->uname, ~0,
 326                                                         v9ses->aname);
 327         if (IS_ERR(fid)) {
 328                 retval = PTR_ERR(fid);
 329                 fid = NULL;
 330                 P9_DPRINTK(P9_DEBUG_ERROR, "cannot attach\n");
 331                 goto error;
 332         }
 333
 334         if ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_SINGLE)
 335                 fid->uid = v9ses->uid;
 336         else
 337                 fid->uid = ~0;
 338
 339 #ifdef CONFIG_9P_FSCACHE
 340         /* register the session for caching */
 341         v9fs_cache_session_get_cookie(v9ses);
 342 #endif
 343
 344         return fid;
 345
 346 error:
 347         bdi_destroy(&v9ses->bdi);
 348         return ERR_PTR(retval);
 349 }
 350
 351 /**
 352  * v9fs_session_close - shutdown a session
 353  * @v9ses: session information structure
 354  *
 355  */
 356
 357 void v9fs_session_close(struct v9fs_session_info *v9ses)
 358 {
 359         if (v9ses->clnt) {
 360                 p9_client_destroy(v9ses->clnt);
 361                 v9ses->clnt = NULL;
 362         }
 363
 364 #ifdef CONFIG_9P_FSCACHE
 365         if (v9ses->fscache) {
 366                 v9fs_cache_session_put_cookie(v9ses);
 367                 kfree(v9ses->cachetag);
 368         }
 369 #endif
 370         __putname(v9ses->uname);
 371         __putname(v9ses->aname);
 372
 373         bdi_destroy(&v9ses->bdi);
 374
 375         spin_lock(&v9fs_sessionlist_lock);
 376         list_del(&v9ses->slist);
 377         spin_unlock(&v9fs_sessionlist_lock);
 378 }
 379
 380 /**
 381  * v9fs_session_cancel - terminate a session
 382  * @v9ses: session to terminate
 383  *
 384  * mark transport as disconnected and cancel all pending requests.
 385  */
 386
 387 void v9fs_session_cancel(struct v9fs_session_info *v9ses) {
 388         P9_DPRINTK(P9_DEBUG_ERROR, "cancel session %p\n", v9ses);
 389         p9_client_disconnect(v9ses->clnt);
 390 }
 391
 392 /**
 393  * v9fs_session_begin_cancel - Begin terminate of a session
 394  * @v9ses: session to terminate
 395  *
 396  * After this call we don't allow any request other than clunk.
 397  */
 398
 399 void v9fs_session_begin_cancel(struct v9fs_session_info *v9ses)
 400 {
 401         P9_DPRINTK(P9_DEBUG_ERROR, "begin cancel session %p\n", v9ses);
 402         p9_client_begin_disconnect(v9ses->clnt);
 403 }
 404
 405 extern int v9fs_error_init(void);
 406
 407 static struct kobject *v9fs_kobj;
 408
 409 #ifdef CONFIG_9P_FSCACHE
 410 /**
 411  * caches_show - list caches associated with a session
 412  *
 413  * Returns the size of buffer written.
 414  */
 415
 416 static ssize_t caches_show(struct kobject *kobj,
 417                            struct kobj_attribute *attr,
 418                            char *buf)
 419 {
 420         ssize_t n = 0, count = 0, limit = PAGE_SIZE;
 421         struct v9fs_session_info *v9ses;
 422
 423         spin_lock(&v9fs_sessionlist_lock);
 424         list_for_each_entry(v9ses, &v9fs_sessionlist, slist) {
 425                 if (v9ses->cachetag) {
 426                         n = snprintf(buf, limit, "%s\n", v9ses->cachetag);
 427                         if (n < 0) {
 428                                 count = n;
 429                                 break;
 430                         }
 431
 432                         count += n;
 433                         limit -= n;
 434                 }
 435         }
 436
 437         spin_unlock(&v9fs_sessionlist_lock);
 438         return count;
 439 }
 440
 441 static struct kobj_attribute v9fs_attr_cache = __ATTR_RO(caches);
 442 #endif /* CONFIG_9P_FSCACHE */
 443
 444 static struct attribute *v9fs_attrs[] = {
 445 #ifdef CONFIG_9P_FSCACHE
 446         &v9fs_attr_cache.attr,
 447 #endif
 448         NULL,
 449 };
 450
 451 static struct attribute_group v9fs_attr_group = {
 452         .attrs = v9fs_attrs,
 453 };
 454
 455 /**
 456  * v9fs_sysfs_init - Initialize the v9fs sysfs interface
 457  *
 458  */
 459
 460 static int v9fs_sysfs_init(void)
 461 {
 462         v9fs_kobj = kobject_create_and_add("9p", fs_kobj);
 463         if (!v9fs_kobj)
 464                 return -ENOMEM;
 465
 466         if (sysfs_create_group(v9fs_kobj, &v9fs_attr_group)) {
 467                 kobject_put(v9fs_kobj);
 468                 return -ENOMEM;
 469         }
 470
 471         return 0;
 472 }
 473
 474 /**
 475  * v9fs_sysfs_cleanup - Unregister the v9fs sysfs interface
 476  *
 477  */
 478
 479 static void v9fs_sysfs_cleanup(void)
 480 {
 481         sysfs_remove_group(v9fs_kobj, &v9fs_attr_group);
 482         kobject_put(v9fs_kobj);
 483 }
 484
 485 static void v9fs_inode_init_once(void *foo)
 486 {
 487         struct v9fs_inode *v9inode = (struct v9fs_inode *)foo;
 488 #ifdef CONFIG_9P_FSCACHE
 489         v9inode->fscache = NULL;
 490         v9inode->fscache_key = NULL;
 491 #endif
 492         inode_init_once(&v9inode->vfs_inode);
 493 }
 494
 495 /**
 496  * v9fs_init_inode_cache - initialize a cache for 9P
 497  * Returns 0 on success.
 498  */
 499 static int v9fs_init_inode_cache(void)
 500 {
 501         v9fs_inode_cache = kmem_cache_create("v9fs_inode_cache",
 502                                           sizeof(struct v9fs_inode),
 503                                           0, (SLAB_RECLAIM_ACCOUNT|
 504                                               SLAB_MEM_SPREAD),
 505                                           v9fs_inode_init_once);
 506         if (!v9fs_inode_cache)
 507                 return -ENOMEM;
 508
 509         return 0;
 510 }
 511
 512 /**
 513  * v9fs_destroy_inode_cache - destroy the cache of 9P inode
 514  *
 515  */
 516 static void v9fs_destroy_inode_cache(void)
 517 {
 518         kmem_cache_destroy(v9fs_inode_cache);
 519 }
 520
 521 static int v9fs_cache_register(void)
 522 {
 523         int ret;
 524         ret = v9fs_init_inode_cache();
 525         if (ret < 0)
 526                 return ret;
 527 #ifdef CONFIG_9P_FSCACHE
 528         return fscache_register_netfs(&v9fs_cache_netfs);
 529 #else
 530         return ret;
 531 #endif
 532 }
 533
 534 static void v9fs_cache_unregister(void)
 535 {
 536         v9fs_destroy_inode_cache();
 537 #ifdef CONFIG_9P_FSCACHE
 538         fscache_unregister_netfs(&v9fs_cache_netfs);
 539 #endif
 540 }
 541
 542 /**
 543  * init_v9fs - Initialize module
 544  *
 545  */
 546
 547 static int __init init_v9fs(void)
 548 {
 549         int err;
 550         printk(KERN_INFO "Installing v9fs 9p2000 file system support\n");
 551         /* TODO: Setup list of registered trasnport modules */
 552         err = register_filesystem(&v9fs_fs_type);
 553         if (err < 0) {
 554                 printk(KERN_ERR "Failed to register filesystem\n");
 555                 return err;
 556         }
 557
 558         err = v9fs_cache_register();
 559         if (err < 0) {
 560                 printk(KERN_ERR "Failed to register v9fs for caching\n");
 561                 goto out_fs_unreg;
 562         }
 563
 564         err = v9fs_sysfs_init();
 565         if (err < 0) {
 566                 printk(KERN_ERR "Failed to register with sysfs\n");
 567                 goto out_sysfs_cleanup;
 568         }
 569
 570         return 0;
 571
 572 out_sysfs_cleanup:
 573         v9fs_sysfs_cleanup();
 574
 575 out_fs_unreg:
 576         unregister_filesystem(&v9fs_fs_type);
 577
 578         return err;
 579 }
 580
 581 /**
 582  * exit_v9fs - shutdown module
 583  *
 584  */
 585
 586 static void __exit exit_v9fs(void)
 587 {
 588         v9fs_sysfs_cleanup();
 589         v9fs_cache_unregister();
 590         unregister_filesystem(&v9fs_fs_type);
 591 }
 592
 593 module_init(init_v9fs)
 594 module_exit(exit_v9fs)
 595
 596 MODULE_AUTHOR("Latchesar Ionkov <lucho@ionkov.net>");
 597 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
 598 MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
 599 MODULE_LICENSE("GPL");