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/cred.h>
  33 #include <linux/parser.h>
  34 #include <linux/idr.h>
  35 #include <linux/slab.h>
  36 #include <linux/seq_file.h>
  37 #include <net/9p/9p.h>
  38 #include <net/9p/client.h>
  39 #include <net/9p/transport.h>
  40 #include "v9fs.h"
  41 #include "v9fs_vfs.h"
  42 #include "cache.h"
  43
  44 static DEFINE_SPINLOCK(v9fs_sessionlist_lock);
  45 static LIST_HEAD(v9fs_sessionlist);
  46 struct kmem_cache *v9fs_inode_cache;
  47
  48 /*
  49  * Option Parsing (code inspired by NFS code)
  50  *  NOTE: each transport will parse its own options
  51  */
  52
  53 enum {
  54         /* Options that take integer arguments */
  55         Opt_debug, Opt_dfltuid, Opt_dfltgid, Opt_afid,
  56         /* String options */
  57         Opt_uname, Opt_remotename, Opt_cache, Opt_cachetag,
  58         /* Options that take no arguments */
  59         Opt_nodevmap,
  60         /* Cache options */
  61         Opt_cache_loose, Opt_fscache, Opt_mmap,
  62         /* Access options */
  63         Opt_access, Opt_posixacl,
  64         /* Error token */
  65         Opt_err
  66 };
  67
  68 static const match_table_t tokens = {
  69         {Opt_debug, "debug=%x"},
  70         {Opt_dfltuid, "dfltuid=%u"},
  71         {Opt_dfltgid, "dfltgid=%u"},
  72         {Opt_afid, "afid=%u"},
  73         {Opt_uname, "uname=%s"},
  74         {Opt_remotename, "aname=%s"},
  75         {Opt_nodevmap, "nodevmap"},
  76         {Opt_cache, "cache=%s"},
  77         {Opt_cache_loose, "loose"},
  78         {Opt_fscache, "fscache"},
  79         {Opt_mmap, "mmap"},
  80         {Opt_cachetag, "cachetag=%s"},
  81         {Opt_access, "access=%s"},
  82         {Opt_posixacl, "posixacl"},
  83         {Opt_err, NULL}
  84 };
  85
  86 static const char *const v9fs_cache_modes[nr__p9_cache_modes] = {
  87         [CACHE_NONE]    = "none",
  88         [CACHE_MMAP]    = "mmap",
  89         [CACHE_LOOSE]   = "loose",
  90         [CACHE_FSCACHE] = "fscache",
  91 };
  92
  93 /* Interpret mount options for cache mode */
  94 static int get_cache_mode(char *s)
  95 {
  96         int version = -EINVAL;
  97
  98         if (!strcmp(s, "loose")) {
  99                 version = CACHE_LOOSE;
 100                 p9_debug(P9_DEBUG_9P, "Cache mode: loose\n");
 101         } else if (!strcmp(s, "fscache")) {
 102                 version = CACHE_FSCACHE;
 103                 p9_debug(P9_DEBUG_9P, "Cache mode: fscache\n");
 104         } else if (!strcmp(s, "mmap")) {
 105                 version = CACHE_MMAP;
 106                 p9_debug(P9_DEBUG_9P, "Cache mode: mmap\n");
 107         } else if (!strcmp(s, "none")) {
 108                 version = CACHE_NONE;
 109                 p9_debug(P9_DEBUG_9P, "Cache mode: none\n");
 110         } else
 111                 pr_info("Unknown Cache mode %s\n", s);
 112         return version;
 113 }
 114
 115 /*
 116  * Display the mount options in /proc/mounts.
 117  */
 118 int v9fs_show_options(struct seq_file *m, struct dentry *root)
 119 {
 120         struct v9fs_session_info *v9ses = root->d_sb->s_fs_info;
 121
 122         if (v9ses->debug)
 123                 seq_printf(m, ",debug=%x", v9ses->debug);
 124         if (!uid_eq(v9ses->dfltuid, V9FS_DEFUID))
 125                 seq_printf(m, ",dfltuid=%u",
 126                            from_kuid_munged(&init_user_ns, v9ses->dfltuid));
 127         if (!gid_eq(v9ses->dfltgid, V9FS_DEFGID))
 128                 seq_printf(m, ",dfltgid=%u",
 129                            from_kgid_munged(&init_user_ns, v9ses->dfltgid));
 130         if (v9ses->afid != ~0)
 131                 seq_printf(m, ",afid=%u", v9ses->afid);
 132         if (strcmp(v9ses->uname, V9FS_DEFUSER) != 0)
 133                 seq_printf(m, ",uname=%s", v9ses->uname);
 134         if (strcmp(v9ses->aname, V9FS_DEFANAME) != 0)
 135                 seq_printf(m, ",aname=%s", v9ses->aname);
 136         if (v9ses->nodev)
 137                 seq_puts(m, ",nodevmap");
 138         if (v9ses->cache)
 139                 seq_printf(m, ",%s", v9fs_cache_modes[v9ses->cache]);
 140 #ifdef CONFIG_9P_FSCACHE
 141         if (v9ses->cachetag && v9ses->cache == CACHE_FSCACHE)
 142                 seq_printf(m, ",cachetag=%s", v9ses->cachetag);
 143 #endif
 144
 145         switch (v9ses->flags & V9FS_ACCESS_MASK) {
 146         case V9FS_ACCESS_USER:
 147                 seq_puts(m, ",access=user");
 148                 break;
 149         case V9FS_ACCESS_ANY:
 150                 seq_puts(m, ",access=any");
 151                 break;
 152         case V9FS_ACCESS_CLIENT:
 153                 seq_puts(m, ",access=client");
 154                 break;
 155         case V9FS_ACCESS_SINGLE:
 156                 seq_printf(m, ",access=%u",
 157                            from_kuid_munged(&init_user_ns, v9ses->uid));
 158                 break;
 159         }
 160
 161         if (v9ses->flags & V9FS_POSIX_ACL)
 162                 seq_puts(m, ",posixacl");
 163
 164         return p9_show_client_options(m, v9ses->clnt);
 165 }
 166
 167 /**
 168  * v9fs_parse_options - parse mount options into session structure
 169  * @v9ses: existing v9fs session information
 170  *
 171  * Return 0 upon success, -ERRNO upon failure.
 172  */
 173
 174 static int v9fs_parse_options(struct v9fs_session_info *v9ses, char *opts)
 175 {
 176         char *options, *tmp_options;
 177         substring_t args[MAX_OPT_ARGS];
 178         char *p;
 179         int option = 0;
 180         char *s, *e;
 181         int ret = 0;
 182
 183         /* setup defaults */
 184         v9ses->afid = ~0;
 185         v9ses->debug = 0;
 186         v9ses->cache = CACHE_NONE;
 187 #ifdef CONFIG_9P_FSCACHE
 188         v9ses->cachetag = NULL;
 189 #endif
 190
 191         if (!opts)
 192                 return 0;
 193
 194         tmp_options = kstrdup(opts, GFP_KERNEL);
 195         if (!tmp_options) {
 196                 ret = -ENOMEM;
 197                 goto fail_option_alloc;
 198         }
 199         options = tmp_options;
 200
 201         while ((p = strsep(&options, ",")) != NULL) {
 202                 int token, r;
 203                 if (!*p)
 204                         continue;
 205                 token = match_token(p, tokens, args);
 206                 switch (token) {
 207                 case Opt_debug:
 208                         r = match_int(&args[0], &option);
 209                         if (r < 0) {
 210                                 p9_debug(P9_DEBUG_ERROR,
 211                                          "integer field, but no integer?\n");
 212                                 ret = r;
 213                                 continue;
 214                         }
 215                         v9ses->debug = option;
 216 #ifdef CONFIG_NET_9P_DEBUG
 217                         p9_debug_level = option;
 218 #endif
 219                         break;
 220
 221                 case Opt_dfltuid:
 222                         r = match_int(&args[0], &option);
 223                         if (r < 0) {
 224                                 p9_debug(P9_DEBUG_ERROR,
 225                                          "integer field, but no integer?\n");
 226                                 ret = r;
 227                                 continue;
 228                         }
 229                         v9ses->dfltuid = make_kuid(current_user_ns(), option);
 230                         if (!uid_valid(v9ses->dfltuid)) {
 231                                 p9_debug(P9_DEBUG_ERROR,
 232                                          "uid field, but not a uid?\n");
 233                                 ret = -EINVAL;
 234                                 continue;
 235                         }
 236                         break;
 237                 case Opt_dfltgid:
 238                         r = match_int(&args[0], &option);
 239                         if (r < 0) {
 240                                 p9_debug(P9_DEBUG_ERROR,
 241                                          "integer field, but no integer?\n");
 242                                 ret = r;
 243                                 continue;
 244                         }
 245                         v9ses->dfltgid = make_kgid(current_user_ns(), option);
 246                         if (!gid_valid(v9ses->dfltgid)) {
 247                                 p9_debug(P9_DEBUG_ERROR,
 248                                          "gid field, but not a gid?\n");
 249                                 ret = -EINVAL;
 250                                 continue;
 251                         }
 252                         break;
 253                 case Opt_afid:
 254                         r = match_int(&args[0], &option);
 255                         if (r < 0) {
 256                                 p9_debug(P9_DEBUG_ERROR,
 257                                          "integer field, but no integer?\n");
 258                                 ret = r;
 259                                 continue;
 260                         }
 261                         v9ses->afid = option;
 262                         break;
 263                 case Opt_uname:
 264                         kfree(v9ses->uname);
 265                         v9ses->uname = match_strdup(&args[0]);
 266                         if (!v9ses->uname) {
 267                                 ret = -ENOMEM;
 268                                 goto free_and_return;
 269                         }
 270                         break;
 271                 case Opt_remotename:
 272                         kfree(v9ses->aname);
 273                         v9ses->aname = match_strdup(&args[0]);
 274                         if (!v9ses->aname) {
 275                                 ret = -ENOMEM;
 276                                 goto free_and_return;
 277                         }
 278                         break;
 279                 case Opt_nodevmap:
 280                         v9ses->nodev = 1;
 281                         break;
 282                 case Opt_cache_loose:
 283                         v9ses->cache = CACHE_LOOSE;
 284                         break;
 285                 case Opt_fscache:
 286                         v9ses->cache = CACHE_FSCACHE;
 287                         break;
 288                 case Opt_mmap:
 289                         v9ses->cache = CACHE_MMAP;
 290                         break;
 291                 case Opt_cachetag:
 292 #ifdef CONFIG_9P_FSCACHE
 293                         kfree(v9ses->cachetag);
 294                         v9ses->cachetag = match_strdup(&args[0]);
 295 #endif
 296                         break;
 297                 case Opt_cache:
 298                         s = match_strdup(&args[0]);
 299                         if (!s) {
 300                                 ret = -ENOMEM;
 301                                 p9_debug(P9_DEBUG_ERROR,
 302                                          "problem allocating copy of cache arg\n");
 303                                 goto free_and_return;
 304                         }
 305                         ret = get_cache_mode(s);
 306                         if (ret == -EINVAL) {
 307                                 kfree(s);
 308                                 goto free_and_return;
 309                         }
 310
 311                         v9ses->cache = ret;
 312                         kfree(s);
 313                         break;
 314
 315                 case Opt_access:
 316                         s = match_strdup(&args[0]);
 317                         if (!s) {
 318                                 ret = -ENOMEM;
 319                                 p9_debug(P9_DEBUG_ERROR,
 320                                          "problem allocating copy of access arg\n");
 321                                 goto free_and_return;
 322                         }
 323
 324                         v9ses->flags &= ~V9FS_ACCESS_MASK;
 325                         if (strcmp(s, "user") == 0)
 326                                 v9ses->flags |= V9FS_ACCESS_USER;
 327                         else if (strcmp(s, "any") == 0)
 328                                 v9ses->flags |= V9FS_ACCESS_ANY;
 329                         else if (strcmp(s, "client") == 0) {
 330                                 v9ses->flags |= V9FS_ACCESS_CLIENT;
 331                         } else {
 332                                 uid_t uid;
 333                                 v9ses->flags |= V9FS_ACCESS_SINGLE;
 334                                 uid = simple_strtoul(s, &e, 10);
 335                                 if (*e != '\0') {
 336                                         ret = -EINVAL;
 337                                         pr_info("Unknown access argument %s\n",
 338                                                 s);
 339                                         kfree(s);
 340                                         goto free_and_return;
 341                                 }
 342                                 v9ses->uid = make_kuid(current_user_ns(), uid);
 343                                 if (!uid_valid(v9ses->uid)) {
 344                                         ret = -EINVAL;
 345                                         pr_info("Uknown uid %s\n", s);
 346                                         kfree(s);
 347                                         goto free_and_return;
 348                                 }
 349                         }
 350
 351                         kfree(s);
 352                         break;
 353
 354                 case Opt_posixacl:
 355 #ifdef CONFIG_9P_FS_POSIX_ACL
 356                         v9ses->flags |= V9FS_POSIX_ACL;
 357 #else
 358                         p9_debug(P9_DEBUG_ERROR,
 359                                  "Not defined CONFIG_9P_FS_POSIX_ACL. Ignoring posixacl option\n");
 360 #endif
 361                         break;
 362
 363                 default:
 364                         continue;
 365                 }
 366         }
 367
 368 free_and_return:
 369         kfree(tmp_options);
 370 fail_option_alloc:
 371         return ret;
 372 }
 373
 374 /**
 375  * v9fs_session_init - initialize session
 376  * @v9ses: session information structure
 377  * @dev_name: device being mounted
 378  * @data: options
 379  *
 380  */
 381
 382 struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
 383                   const char *dev_name, char *data)
 384 {
 385         struct p9_fid *fid;
 386         int rc = -ENOMEM;
 387
 388         v9ses->uname = kstrdup(V9FS_DEFUSER, GFP_KERNEL);
 389         if (!v9ses->uname)
 390                 goto err_names;
 391
 392         v9ses->aname = kstrdup(V9FS_DEFANAME, GFP_KERNEL);
 393         if (!v9ses->aname)
 394                 goto err_names;
 395         init_rwsem(&v9ses->rename_sem);
 396
 397         v9ses->uid = INVALID_UID;
 398         v9ses->dfltuid = V9FS_DEFUID;
 399         v9ses->dfltgid = V9FS_DEFGID;
 400
 401         v9ses->clnt = p9_client_create(dev_name, data);
 402         if (IS_ERR(v9ses->clnt)) {
 403                 rc = PTR_ERR(v9ses->clnt);
 404                 p9_debug(P9_DEBUG_ERROR, "problem initializing 9p client\n");
 405                 goto err_names;
 406         }
 407
 408         v9ses->flags = V9FS_ACCESS_USER;
 409
 410         if (p9_is_proto_dotl(v9ses->clnt)) {
 411                 v9ses->flags = V9FS_ACCESS_CLIENT;
 412                 v9ses->flags |= V9FS_PROTO_2000L;
 413         } else if (p9_is_proto_dotu(v9ses->clnt)) {
 414                 v9ses->flags |= V9FS_PROTO_2000U;
 415         }
 416
 417         rc = v9fs_parse_options(v9ses, data);
 418         if (rc < 0)
 419                 goto err_clnt;
 420
 421         v9ses->maxdata = v9ses->clnt->msize - P9_IOHDRSZ;
 422
 423         if (!v9fs_proto_dotl(v9ses) &&
 424             ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
 425                 /*
 426                  * We support ACCESS_CLIENT only for dotl.
 427                  * Fall back to ACCESS_USER
 428                  */
 429                 v9ses->flags &= ~V9FS_ACCESS_MASK;
 430                 v9ses->flags |= V9FS_ACCESS_USER;
 431         }
 432         /*FIXME !! */
 433         /* for legacy mode, fall back to V9FS_ACCESS_ANY */
 434         if (!(v9fs_proto_dotu(v9ses) || v9fs_proto_dotl(v9ses)) &&
 435                 ((v9ses->flags&V9FS_ACCESS_MASK) == V9FS_ACCESS_USER)) {
 436
 437                 v9ses->flags &= ~V9FS_ACCESS_MASK;
 438                 v9ses->flags |= V9FS_ACCESS_ANY;
 439                 v9ses->uid = INVALID_UID;
 440         }
 441         if (!v9fs_proto_dotl(v9ses) ||
 442                 !((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
 443                 /*
 444                  * We support ACL checks on clinet only if the protocol is
 445                  * 9P2000.L and access is V9FS_ACCESS_CLIENT.
 446                  */
 447                 v9ses->flags &= ~V9FS_ACL_MASK;
 448         }
 449
 450         fid = p9_client_attach(v9ses->clnt, NULL, v9ses->uname, INVALID_UID,
 451                                                         v9ses->aname);
 452         if (IS_ERR(fid)) {
 453                 rc = PTR_ERR(fid);
 454                 p9_debug(P9_DEBUG_ERROR, "cannot attach\n");
 455                 goto err_clnt;
 456         }
 457
 458         if ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_SINGLE)
 459                 fid->uid = v9ses->uid;
 460         else
 461                 fid->uid = INVALID_UID;
 462
 463 #ifdef CONFIG_9P_FSCACHE
 464         /* register the session for caching */
 465         v9fs_cache_session_get_cookie(v9ses);
 466 #endif
 467         spin_lock(&v9fs_sessionlist_lock);
 468         list_add(&v9ses->slist, &v9fs_sessionlist);
 469         spin_unlock(&v9fs_sessionlist_lock);
 470
 471         return fid;
 472
 473 err_clnt:
 474         p9_client_destroy(v9ses->clnt);
 475 err_names:
 476         kfree(v9ses->uname);
 477         kfree(v9ses->aname);
 478         return ERR_PTR(rc);
 479 }
 480
 481 /**
 482  * v9fs_session_close - shutdown a session
 483  * @v9ses: session information structure
 484  *
 485  */
 486
 487 void v9fs_session_close(struct v9fs_session_info *v9ses)
 488 {
 489         if (v9ses->clnt) {
 490                 p9_client_destroy(v9ses->clnt);
 491                 v9ses->clnt = NULL;
 492         }
 493
 494 #ifdef CONFIG_9P_FSCACHE
 495         if (v9ses->fscache) {
 496                 v9fs_cache_session_put_cookie(v9ses);
 497                 kfree(v9ses->cachetag);
 498         }
 499 #endif
 500         kfree(v9ses->uname);
 501         kfree(v9ses->aname);
 502
 503         spin_lock(&v9fs_sessionlist_lock);
 504         list_del(&v9ses->slist);
 505         spin_unlock(&v9fs_sessionlist_lock);
 506 }
 507
 508 /**
 509  * v9fs_session_cancel - terminate a session
 510  * @v9ses: session to terminate
 511  *
 512  * mark transport as disconnected and cancel all pending requests.
 513  */
 514
 515 void v9fs_session_cancel(struct v9fs_session_info *v9ses) {
 516         p9_debug(P9_DEBUG_ERROR, "cancel session %p\n", v9ses);
 517         p9_client_disconnect(v9ses->clnt);
 518 }
 519
 520 /**
 521  * v9fs_session_begin_cancel - Begin terminate of a session
 522  * @v9ses: session to terminate
 523  *
 524  * After this call we don't allow any request other than clunk.
 525  */
 526
 527 void v9fs_session_begin_cancel(struct v9fs_session_info *v9ses)
 528 {
 529         p9_debug(P9_DEBUG_ERROR, "begin cancel session %p\n", v9ses);
 530         p9_client_begin_disconnect(v9ses->clnt);
 531 }
 532
 533 extern int v9fs_error_init(void);
 534
 535 static struct kobject *v9fs_kobj;
 536
 537 #ifdef CONFIG_9P_FSCACHE
 538 /**
 539  * caches_show - list caches associated with a session
 540  *
 541  * Returns the size of buffer written.
 542  */
 543
 544 static ssize_t caches_show(struct kobject *kobj,
 545                            struct kobj_attribute *attr,
 546                            char *buf)
 547 {
 548         ssize_t n = 0, count = 0, limit = PAGE_SIZE;
 549         struct v9fs_session_info *v9ses;
 550
 551         spin_lock(&v9fs_sessionlist_lock);
 552         list_for_each_entry(v9ses, &v9fs_sessionlist, slist) {
 553                 if (v9ses->cachetag) {
 554                         n = snprintf(buf, limit, "%s\n", v9ses->cachetag);
 555                         if (n < 0) {
 556                                 count = n;
 557                                 break;
 558                         }
 559
 560                         count += n;
 561                         limit -= n;
 562                 }
 563         }
 564
 565         spin_unlock(&v9fs_sessionlist_lock);
 566         return count;
 567 }
 568
 569 static struct kobj_attribute v9fs_attr_cache = __ATTR_RO(caches);
 570 #endif /* CONFIG_9P_FSCACHE */
 571
 572 static struct attribute *v9fs_attrs[] = {
 573 #ifdef CONFIG_9P_FSCACHE
 574         &v9fs_attr_cache.attr,
 575 #endif
 576         NULL,
 577 };
 578
 579 static struct attribute_group v9fs_attr_group = {
 580         .attrs = v9fs_attrs,
 581 };
 582
 583 /**
 584  * v9fs_sysfs_init - Initialize the v9fs sysfs interface
 585  *
 586  */
 587
 588 static int __init v9fs_sysfs_init(void)
 589 {
 590         v9fs_kobj = kobject_create_and_add("9p", fs_kobj);
 591         if (!v9fs_kobj)
 592                 return -ENOMEM;
 593
 594         if (sysfs_create_group(v9fs_kobj, &v9fs_attr_group)) {
 595                 kobject_put(v9fs_kobj);
 596                 return -ENOMEM;
 597         }
 598
 599         return 0;
 600 }
 601
 602 /**
 603  * v9fs_sysfs_cleanup - Unregister the v9fs sysfs interface
 604  *
 605  */
 606
 607 static void v9fs_sysfs_cleanup(void)
 608 {
 609         sysfs_remove_group(v9fs_kobj, &v9fs_attr_group);
 610         kobject_put(v9fs_kobj);
 611 }
 612
 613 static void v9fs_inode_init_once(void *foo)
 614 {
 615         struct v9fs_inode *v9inode = (struct v9fs_inode *)foo;
 616 #ifdef CONFIG_9P_FSCACHE
 617         v9inode->fscache = NULL;
 618 #endif
 619         memset(&v9inode->qid, 0, sizeof(v9inode->qid));
 620         inode_init_once(&v9inode->vfs_inode);
 621 }
 622
 623 /**
 624  * v9fs_init_inode_cache - initialize a cache for 9P
 625  * Returns 0 on success.
 626  */
 627 static int v9fs_init_inode_cache(void)
 628 {
 629         v9fs_inode_cache = kmem_cache_create("v9fs_inode_cache",
 630                                           sizeof(struct v9fs_inode),
 631                                           0, (SLAB_RECLAIM_ACCOUNT|
 632                                               SLAB_MEM_SPREAD|SLAB_ACCOUNT),
 633                                           v9fs_inode_init_once);
 634         if (!v9fs_inode_cache)
 635                 return -ENOMEM;
 636
 637         return 0;
 638 }
 639
 640 /**
 641  * v9fs_destroy_inode_cache - destroy the cache of 9P inode
 642  *
 643  */
 644 static void v9fs_destroy_inode_cache(void)
 645 {
 646         /*
 647          * Make sure all delayed rcu free inodes are flushed before we
 648          * destroy cache.
 649          */
 650         rcu_barrier();
 651         kmem_cache_destroy(v9fs_inode_cache);
 652 }
 653
 654 static int v9fs_cache_register(void)
 655 {
 656         int ret;
 657         ret = v9fs_init_inode_cache();
 658         if (ret < 0)
 659                 return ret;
 660 #ifdef CONFIG_9P_FSCACHE
 661         ret = fscache_register_netfs(&v9fs_cache_netfs);
 662         if (ret < 0)
 663                 v9fs_destroy_inode_cache();
 664 #endif
 665         return ret;
 666 }
 667
 668 static void v9fs_cache_unregister(void)
 669 {
 670         v9fs_destroy_inode_cache();
 671 #ifdef CONFIG_9P_FSCACHE
 672         fscache_unregister_netfs(&v9fs_cache_netfs);
 673 #endif
 674 }
 675
 676 /**
 677  * init_v9fs - Initialize module
 678  *
 679  */
 680
 681 static int __init init_v9fs(void)
 682 {
 683         int err;
 684         pr_info("Installing v9fs 9p2000 file system support\n");
 685         /* TODO: Setup list of registered trasnport modules */
 686
 687         err = v9fs_cache_register();
 688         if (err < 0) {
 689                 pr_err("Failed to register v9fs for caching\n");
 690                 return err;
 691         }
 692
 693         err = v9fs_sysfs_init();
 694         if (err < 0) {
 695                 pr_err("Failed to register with sysfs\n");
 696                 goto out_cache;
 697         }
 698         err = register_filesystem(&v9fs_fs_type);
 699         if (err < 0) {
 700                 pr_err("Failed to register filesystem\n");
 701                 goto out_sysfs_cleanup;
 702         }
 703
 704         return 0;
 705
 706 out_sysfs_cleanup:
 707         v9fs_sysfs_cleanup();
 708
 709 out_cache:
 710         v9fs_cache_unregister();
 711
 712         return err;
 713 }
 714
 715 /**
 716  * exit_v9fs - shutdown module
 717  *
 718  */
 719
 720 static void __exit exit_v9fs(void)
 721 {
 722         v9fs_sysfs_cleanup();
 723         v9fs_cache_unregister();
 724         unregister_filesystem(&v9fs_fs_type);
 725 }
 726
 727 module_init(init_v9fs)
 728 module_exit(exit_v9fs)
 729
 730 MODULE_AUTHOR("Latchesar Ionkov <lucho@ionkov.net>");
 731 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
 732 MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
 733 MODULE_LICENSE("GPL");