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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  27
  28 #include <linux/module.h>
  29 #include <linux/errno.h>
  30 #include <linux/fs.h>
  31 #include <linux/sched.h>
  32 #include <linux/parser.h>
  33 #include <linux/idr.h>
  34 #include <linux/slab.h>
  35 #include <net/9p/9p.h>
  36 #include <net/9p/client.h>
  37 #include <net/9p/transport.h>
  38 #include "v9fs.h"
  39 #include "v9fs_vfs.h"
  40 #include "cache.h"
  41
  42 static DEFINE_SPINLOCK(v9fs_sessionlist_lock);
  43 static LIST_HEAD(v9fs_sessionlist);
  44 struct kmem_cache *v9fs_inode_cache;
  45
  46 /*
  47  * Option Parsing (code inspired by NFS code)
  48  *  NOTE: each transport will parse its own options
  49  */
  50
  51 enum {
  52         /* Options that take integer arguments */
  53         Opt_debug, Opt_dfltuid, Opt_dfltgid, Opt_afid,
  54         /* String options */
  55         Opt_uname, Opt_remotename, Opt_trans, Opt_cache, Opt_cachetag,
  56         /* Options that take no arguments */
  57         Opt_nodevmap,
  58         /* Cache options */
  59         Opt_cache_loose, Opt_fscache,
  60         /* Access options */
  61         Opt_access, Opt_posixacl,
  62         /* Error token */
  63         Opt_err
  64 };
  65
  66 static const match_table_t tokens = {
  67         {Opt_debug, "debug=%x"},
  68         {Opt_dfltuid, "dfltuid=%u"},
  69         {Opt_dfltgid, "dfltgid=%u"},
  70         {Opt_afid, "afid=%u"},
  71         {Opt_uname, "uname=%s"},
  72         {Opt_remotename, "aname=%s"},
  73         {Opt_nodevmap, "nodevmap"},
  74         {Opt_cache, "cache=%s"},
  75         {Opt_cache_loose, "loose"},
  76         {Opt_fscache, "fscache"},
  77         {Opt_cachetag, "cachetag=%s"},
  78         {Opt_access, "access=%s"},
  79         {Opt_posixacl, "posixacl"},
  80         {Opt_err, NULL}
  81 };
  82
  83 /* Interpret mount options for cache mode */
  84 static int get_cache_mode(char *s)
  85 {
  86         int version = -EINVAL;
  87
  88         if (!strcmp(s, "loose")) {
  89                 version = CACHE_LOOSE;
  90                 p9_debug(P9_DEBUG_9P, "Cache mode: loose\n");
  91         } else if (!strcmp(s, "fscache")) {
  92                 version = CACHE_FSCACHE;
  93                 p9_debug(P9_DEBUG_9P, "Cache mode: fscache\n");
  94         } else if (!strcmp(s, "none")) {
  95                 version = CACHE_NONE;
  96                 p9_debug(P9_DEBUG_9P, "Cache mode: none\n");
  97         } else
  98                 pr_info("Unknown Cache mode %s\n", s);
  99         return version;
 100 }
 101
 102 /**
 103  * v9fs_parse_options - parse mount options into session structure
 104  * @v9ses: existing v9fs session information
 105  *
 106  * Return 0 upon success, -ERRNO upon failure.
 107  */
 108
 109 static int v9fs_parse_options(struct v9fs_session_info *v9ses, char *opts)
 110 {
 111         char *options, *tmp_options;
 112         substring_t args[MAX_OPT_ARGS];
 113         char *p;
 114         int option = 0;
 115         char *s, *e;
 116         int ret = 0;
 117
 118         /* setup defaults */
 119         v9ses->afid = ~0;
 120         v9ses->debug = 0;
 121         v9ses->cache = CACHE_NONE;
 122 #ifdef CONFIG_9P_FSCACHE
 123         v9ses->cachetag = NULL;
 124 #endif
 125
 126         if (!opts)
 127                 return 0;
 128
 129         tmp_options = kstrdup(opts, GFP_KERNEL);
 130         if (!tmp_options) {
 131                 ret = -ENOMEM;
 132                 goto fail_option_alloc;
 133         }
 134         options = tmp_options;
 135
 136         while ((p = strsep(&options, ",")) != NULL) {
 137                 int token, r;
 138                 if (!*p)
 139                         continue;
 140                 token = match_token(p, tokens, args);
 141                 switch (token) {
 142                 case Opt_debug:
 143                         r = match_int(&args[0], &option);
 144                         if (r < 0) {
 145                                 p9_debug(P9_DEBUG_ERROR,
 146                                          "integer field, but no integer?\n");
 147                                 ret = r;
 148                                 continue;
 149                         }
 150                         v9ses->debug = option;
 151 #ifdef CONFIG_NET_9P_DEBUG
 152                         p9_debug_level = option;
 153 #endif
 154                         break;
 155
 156                 case Opt_dfltuid:
 157                         r = match_int(&args[0], &option);
 158                         if (r < 0) {
 159                                 p9_debug(P9_DEBUG_ERROR,
 160                                          "integer field, but no integer?\n");
 161                                 ret = r;
 162                                 continue;
 163                         }
 164                         v9ses->dfltuid = option;
 165                         break;
 166                 case Opt_dfltgid:
 167                         r = match_int(&args[0], &option);
 168                         if (r < 0) {
 169                                 p9_debug(P9_DEBUG_ERROR,
 170                                          "integer field, but no integer?\n");
 171                                 ret = r;
 172                                 continue;
 173                         }
 174                         v9ses->dfltgid = option;
 175                         break;
 176                 case Opt_afid:
 177                         r = match_int(&args[0], &option);
 178                         if (r < 0) {
 179                                 p9_debug(P9_DEBUG_ERROR,
 180                                          "integer field, but no integer?\n");
 181                                 ret = r;
 182                                 continue;
 183                         }
 184                         v9ses->afid = option;
 185                         break;
 186                 case Opt_uname:
 187                         match_strlcpy(v9ses->uname, &args[0], PATH_MAX);
 188                         break;
 189                 case Opt_remotename:
 190                         match_strlcpy(v9ses->aname, &args[0], PATH_MAX);
 191                         break;
 192                 case Opt_nodevmap:
 193                         v9ses->nodev = 1;
 194                         break;
 195                 case Opt_cache_loose:
 196                         v9ses->cache = CACHE_LOOSE;
 197                         break;
 198                 case Opt_fscache:
 199                         v9ses->cache = CACHE_FSCACHE;
 200                         break;
 201                 case Opt_cachetag:
 202 #ifdef CONFIG_9P_FSCACHE
 203                         v9ses->cachetag = match_strdup(&args[0]);
 204 #endif
 205                         break;
 206                 case Opt_cache:
 207                         s = match_strdup(&args[0]);
 208                         if (!s) {
 209                                 ret = -ENOMEM;
 210                                 p9_debug(P9_DEBUG_ERROR,
 211                                          "problem allocating copy of cache arg\n");
 212                                 goto free_and_return;
 213                         }
 214                         ret = get_cache_mode(s);
 215                         if (ret == -EINVAL) {
 216                                 kfree(s);
 217                                 goto free_and_return;
 218                         }
 219
 220                         v9ses->cache = ret;
 221                         kfree(s);
 222                         break;
 223
 224                 case Opt_access:
 225                         s = match_strdup(&args[0]);
 226                         if (!s) {
 227                                 ret = -ENOMEM;
 228                                 p9_debug(P9_DEBUG_ERROR,
 229                                          "problem allocating copy of access arg\n");
 230                                 goto free_and_return;
 231                         }
 232
 233                         v9ses->flags &= ~V9FS_ACCESS_MASK;
 234                         if (strcmp(s, "user") == 0)
 235                                 v9ses->flags |= V9FS_ACCESS_USER;
 236                         else if (strcmp(s, "any") == 0)
 237                                 v9ses->flags |= V9FS_ACCESS_ANY;
 238                         else if (strcmp(s, "client") == 0) {
 239                                 v9ses->flags |= V9FS_ACCESS_CLIENT;
 240                         } else {
 241                                 v9ses->flags |= V9FS_ACCESS_SINGLE;
 242                                 v9ses->uid = simple_strtoul(s, &e, 10);
 243                                 if (*e != '\0') {
 244                                         ret = -EINVAL;
 245                                         pr_info("Unknown access argument %s\n",
 246                                                 s);
 247                                         kfree(s);
 248                                         goto free_and_return;
 249                                 }
 250                         }
 251
 252                         kfree(s);
 253                         break;
 254
 255                 case Opt_posixacl:
 256 #ifdef CONFIG_9P_FS_POSIX_ACL
 257                         v9ses->flags |= V9FS_POSIX_ACL;
 258 #else
 259                         p9_debug(P9_DEBUG_ERROR,
 260                                  "Not defined CONFIG_9P_FS_POSIX_ACL. Ignoring posixacl option\n");
 261 #endif
 262                         break;
 263
 264                 default:
 265                         continue;
 266                 }
 267         }
 268
 269 free_and_return:
 270         kfree(tmp_options);
 271 fail_option_alloc:
 272         return ret;
 273 }
 274
 275 /**
 276  * v9fs_session_init - initialize session
 277  * @v9ses: session information structure
 278  * @dev_name: device being mounted
 279  * @data: options
 280  *
 281  */
 282
 283 struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
 284                   const char *dev_name, char *data)
 285 {
 286         int retval = -EINVAL;
 287         struct p9_fid *fid;
 288         int rc;
 289
 290         v9ses->uname = __getname();
 291         if (!v9ses->uname)
 292                 return ERR_PTR(-ENOMEM);
 293
 294         v9ses->aname = __getname();
 295         if (!v9ses->aname) {
 296                 __putname(v9ses->uname);
 297                 return ERR_PTR(-ENOMEM);
 298         }
 299         init_rwsem(&v9ses->rename_sem);
 300
 301         rc = bdi_setup_and_register(&v9ses->bdi, "9p", BDI_CAP_MAP_COPY);
 302         if (rc) {
 303                 __putname(v9ses->aname);
 304                 __putname(v9ses->uname);
 305                 return ERR_PTR(rc);
 306         }
 307
 308         spin_lock(&v9fs_sessionlist_lock);
 309         list_add(&v9ses->slist, &v9fs_sessionlist);
 310         spin_unlock(&v9fs_sessionlist_lock);
 311
 312         strcpy(v9ses->uname, V9FS_DEFUSER);
 313         strcpy(v9ses->aname, V9FS_DEFANAME);
 314         v9ses->uid = ~0;
 315         v9ses->dfltuid = V9FS_DEFUID;
 316         v9ses->dfltgid = V9FS_DEFGID;
 317
 318         v9ses->clnt = p9_client_create(dev_name, data);
 319         if (IS_ERR(v9ses->clnt)) {
 320                 retval = PTR_ERR(v9ses->clnt);
 321                 v9ses->clnt = NULL;
 322                 p9_debug(P9_DEBUG_ERROR, "problem initializing 9p client\n");
 323                 goto error;
 324         }
 325
 326         v9ses->flags = V9FS_ACCESS_USER;
 327
 328         if (p9_is_proto_dotl(v9ses->clnt)) {
 329                 v9ses->flags = V9FS_ACCESS_CLIENT;
 330                 v9ses->flags |= V9FS_PROTO_2000L;
 331         } else if (p9_is_proto_dotu(v9ses->clnt)) {
 332                 v9ses->flags |= V9FS_PROTO_2000U;
 333         }
 334
 335         rc = v9fs_parse_options(v9ses, data);
 336         if (rc < 0) {
 337                 retval = rc;
 338                 goto error;
 339         }
 340
 341         v9ses->maxdata = v9ses->clnt->msize - P9_IOHDRSZ;
 342
 343         if (!v9fs_proto_dotl(v9ses) &&
 344             ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
 345                 /*
 346                  * We support ACCESS_CLIENT only for dotl.
 347                  * Fall back to ACCESS_USER
 348                  */
 349                 v9ses->flags &= ~V9FS_ACCESS_MASK;
 350                 v9ses->flags |= V9FS_ACCESS_USER;
 351         }
 352         /*FIXME !! */
 353         /* for legacy mode, fall back to V9FS_ACCESS_ANY */
 354         if (!(v9fs_proto_dotu(v9ses) || v9fs_proto_dotl(v9ses)) &&
 355                 ((v9ses->flags&V9FS_ACCESS_MASK) == V9FS_ACCESS_USER)) {
 356
 357                 v9ses->flags &= ~V9FS_ACCESS_MASK;
 358                 v9ses->flags |= V9FS_ACCESS_ANY;
 359                 v9ses->uid = ~0;
 360         }
 361         if (!v9fs_proto_dotl(v9ses) ||
 362                 !((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
 363                 /*
 364                  * We support ACL checks on clinet only if the protocol is
 365                  * 9P2000.L and access is V9FS_ACCESS_CLIENT.
 366                  */
 367                 v9ses->flags &= ~V9FS_ACL_MASK;
 368         }
 369
 370         fid = p9_client_attach(v9ses->clnt, NULL, v9ses->uname, ~0,
 371                                                         v9ses->aname);
 372         if (IS_ERR(fid)) {
 373                 retval = PTR_ERR(fid);
 374                 fid = NULL;
 375                 p9_debug(P9_DEBUG_ERROR, "cannot attach\n");
 376                 goto error;
 377         }
 378
 379         if ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_SINGLE)
 380                 fid->uid = v9ses->uid;
 381         else
 382                 fid->uid = ~0;
 383
 384 #ifdef CONFIG_9P_FSCACHE
 385         /* register the session for caching */
 386         v9fs_cache_session_get_cookie(v9ses);
 387 #endif
 388
 389         return fid;
 390
 391 error:
 392         bdi_destroy(&v9ses->bdi);
 393         return ERR_PTR(retval);
 394 }
 395
 396 /**
 397  * v9fs_session_close - shutdown a session
 398  * @v9ses: session information structure
 399  *
 400  */
 401
 402 void v9fs_session_close(struct v9fs_session_info *v9ses)
 403 {
 404         if (v9ses->clnt) {
 405                 p9_client_destroy(v9ses->clnt);
 406                 v9ses->clnt = NULL;
 407         }
 408
 409 #ifdef CONFIG_9P_FSCACHE
 410         if (v9ses->fscache) {
 411                 v9fs_cache_session_put_cookie(v9ses);
 412                 kfree(v9ses->cachetag);
 413         }
 414 #endif
 415         __putname(v9ses->uname);
 416         __putname(v9ses->aname);
 417
 418         bdi_destroy(&v9ses->bdi);
 419
 420         spin_lock(&v9fs_sessionlist_lock);
 421         list_del(&v9ses->slist);
 422         spin_unlock(&v9fs_sessionlist_lock);
 423 }
 424
 425 /**
 426  * v9fs_session_cancel - terminate a session
 427  * @v9ses: session to terminate
 428  *
 429  * mark transport as disconnected and cancel all pending requests.
 430  */
 431
 432 void v9fs_session_cancel(struct v9fs_session_info *v9ses) {
 433         p9_debug(P9_DEBUG_ERROR, "cancel session %p\n", v9ses);
 434         p9_client_disconnect(v9ses->clnt);
 435 }
 436
 437 /**
 438  * v9fs_session_begin_cancel - Begin terminate of a session
 439  * @v9ses: session to terminate
 440  *
 441  * After this call we don't allow any request other than clunk.
 442  */
 443
 444 void v9fs_session_begin_cancel(struct v9fs_session_info *v9ses)
 445 {
 446         p9_debug(P9_DEBUG_ERROR, "begin cancel session %p\n", v9ses);
 447         p9_client_begin_disconnect(v9ses->clnt);
 448 }
 449
 450 extern int v9fs_error_init(void);
 451
 452 static struct kobject *v9fs_kobj;
 453
 454 #ifdef CONFIG_9P_FSCACHE
 455 /**
 456  * caches_show - list caches associated with a session
 457  *
 458  * Returns the size of buffer written.
 459  */
 460
 461 static ssize_t caches_show(struct kobject *kobj,
 462                            struct kobj_attribute *attr,
 463                            char *buf)
 464 {
 465         ssize_t n = 0, count = 0, limit = PAGE_SIZE;
 466         struct v9fs_session_info *v9ses;
 467
 468         spin_lock(&v9fs_sessionlist_lock);
 469         list_for_each_entry(v9ses, &v9fs_sessionlist, slist) {
 470                 if (v9ses->cachetag) {
 471                         n = snprintf(buf, limit, "%s\n", v9ses->cachetag);
 472                         if (n < 0) {
 473                                 count = n;
 474                                 break;
 475                         }
 476
 477                         count += n;
 478                         limit -= n;
 479                 }
 480         }
 481
 482         spin_unlock(&v9fs_sessionlist_lock);
 483         return count;
 484 }
 485
 486 static struct kobj_attribute v9fs_attr_cache = __ATTR_RO(caches);
 487 #endif /* CONFIG_9P_FSCACHE */
 488
 489 static struct attribute *v9fs_attrs[] = {
 490 #ifdef CONFIG_9P_FSCACHE
 491         &v9fs_attr_cache.attr,
 492 #endif
 493         NULL,
 494 };
 495
 496 static struct attribute_group v9fs_attr_group = {
 497         .attrs = v9fs_attrs,
 498 };
 499
 500 /**
 501  * v9fs_sysfs_init - Initialize the v9fs sysfs interface
 502  *
 503  */
 504
 505 static int v9fs_sysfs_init(void)
 506 {
 507         v9fs_kobj = kobject_create_and_add("9p", fs_kobj);
 508         if (!v9fs_kobj)
 509                 return -ENOMEM;
 510
 511         if (sysfs_create_group(v9fs_kobj, &v9fs_attr_group)) {
 512                 kobject_put(v9fs_kobj);
 513                 return -ENOMEM;
 514         }
 515
 516         return 0;
 517 }
 518
 519 /**
 520  * v9fs_sysfs_cleanup - Unregister the v9fs sysfs interface
 521  *
 522  */
 523
 524 static void v9fs_sysfs_cleanup(void)
 525 {
 526         sysfs_remove_group(v9fs_kobj, &v9fs_attr_group);
 527         kobject_put(v9fs_kobj);
 528 }
 529
 530 static void v9fs_inode_init_once(void *foo)
 531 {
 532         struct v9fs_inode *v9inode = (struct v9fs_inode *)foo;
 533 #ifdef CONFIG_9P_FSCACHE
 534         v9inode->fscache = NULL;
 535 #endif
 536         memset(&v9inode->qid, 0, sizeof(v9inode->qid));
 537         inode_init_once(&v9inode->vfs_inode);
 538 }
 539
 540 /**
 541  * v9fs_init_inode_cache - initialize a cache for 9P
 542  * Returns 0 on success.
 543  */
 544 static int v9fs_init_inode_cache(void)
 545 {
 546         v9fs_inode_cache = kmem_cache_create("v9fs_inode_cache",
 547                                           sizeof(struct v9fs_inode),
 548                                           0, (SLAB_RECLAIM_ACCOUNT|
 549                                               SLAB_MEM_SPREAD),
 550                                           v9fs_inode_init_once);
 551         if (!v9fs_inode_cache)
 552                 return -ENOMEM;
 553
 554         return 0;
 555 }
 556
 557 /**
 558  * v9fs_destroy_inode_cache - destroy the cache of 9P inode
 559  *
 560  */
 561 static void v9fs_destroy_inode_cache(void)
 562 {
 563         kmem_cache_destroy(v9fs_inode_cache);
 564 }
 565
 566 static int v9fs_cache_register(void)
 567 {
 568         int ret;
 569         ret = v9fs_init_inode_cache();
 570         if (ret < 0)
 571                 return ret;
 572 #ifdef CONFIG_9P_FSCACHE
 573         return fscache_register_netfs(&v9fs_cache_netfs);
 574 #else
 575         return ret;
 576 #endif
 577 }
 578
 579 static void v9fs_cache_unregister(void)
 580 {
 581         v9fs_destroy_inode_cache();
 582 #ifdef CONFIG_9P_FSCACHE
 583         fscache_unregister_netfs(&v9fs_cache_netfs);
 584 #endif
 585 }
 586
 587 /**
 588  * init_v9fs - Initialize module
 589  *
 590  */
 591
 592 static int __init init_v9fs(void)
 593 {
 594         int err;
 595         pr_info("Installing v9fs 9p2000 file system support\n");
 596         /* TODO: Setup list of registered trasnport modules */
 597         err = register_filesystem(&v9fs_fs_type);
 598         if (err < 0) {
 599                 pr_err("Failed to register filesystem\n");
 600                 return err;
 601         }
 602
 603         err = v9fs_cache_register();
 604         if (err < 0) {
 605                 pr_err("Failed to register v9fs for caching\n");
 606                 goto out_fs_unreg;
 607         }
 608
 609         err = v9fs_sysfs_init();
 610         if (err < 0) {
 611                 pr_err("Failed to register with sysfs\n");
 612                 goto out_sysfs_cleanup;
 613         }
 614
 615         return 0;
 616
 617 out_sysfs_cleanup:
 618         v9fs_sysfs_cleanup();
 619
 620 out_fs_unreg:
 621         unregister_filesystem(&v9fs_fs_type);
 622
 623         return err;
 624 }
 625
 626 /**
 627  * exit_v9fs - shutdown module
 628  *
 629  */
 630
 631 static void __exit exit_v9fs(void)
 632 {
 633         v9fs_sysfs_cleanup();
 634         v9fs_cache_unregister();
 635         unregister_filesystem(&v9fs_fs_type);
 636 }
 637
 638 module_init(init_v9fs)
 639 module_exit(exit_v9fs)
 640
 641 MODULE_AUTHOR("Latchesar Ionkov <lucho@ionkov.net>");
 642 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
 643 MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
 644 MODULE_LICENSE("GPL");