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                         } else {
 214                                 v9ses->debug = option;
 215 #ifdef CONFIG_NET_9P_DEBUG
 216                                 p9_debug_level = option;
 217 #endif
 218                         }
 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                         }
 235                         break;
 236                 case Opt_dfltgid:
 237                         r = match_int(&args[0], &option);
 238                         if (r < 0) {
 239                                 p9_debug(P9_DEBUG_ERROR,
 240                                          "integer field, but no integer?\n");
 241                                 ret = r;
 242                                 continue;
 243                         }
 244                         v9ses->dfltgid = make_kgid(current_user_ns(), option);
 245                         if (!gid_valid(v9ses->dfltgid)) {
 246                                 p9_debug(P9_DEBUG_ERROR,
 247                                          "gid field, but not a gid?\n");
 248                                 ret = -EINVAL;
 249                         }
 250                         break;
 251                 case Opt_afid:
 252                         r = match_int(&args[0], &option);
 253                         if (r < 0) {
 254                                 p9_debug(P9_DEBUG_ERROR,
 255                                          "integer field, but no integer?\n");
 256                                 ret = r;
 257                         } else {
 258                                 v9ses->afid = option;
 259                         }
 260                         break;
 261                 case Opt_uname:
 262                         kfree(v9ses->uname);
 263                         v9ses->uname = match_strdup(&args[0]);
 264                         if (!v9ses->uname) {
 265                                 ret = -ENOMEM;
 266                                 goto free_and_return;
 267                         }
 268                         break;
 269                 case Opt_remotename:
 270                         kfree(v9ses->aname);
 271                         v9ses->aname = match_strdup(&args[0]);
 272                         if (!v9ses->aname) {
 273                                 ret = -ENOMEM;
 274                                 goto free_and_return;
 275                         }
 276                         break;
 277                 case Opt_nodevmap:
 278                         v9ses->nodev = 1;
 279                         break;
 280                 case Opt_cache_loose:
 281                         v9ses->cache = CACHE_LOOSE;
 282                         break;
 283                 case Opt_fscache:
 284                         v9ses->cache = CACHE_FSCACHE;
 285                         break;
 286                 case Opt_mmap:
 287                         v9ses->cache = CACHE_MMAP;
 288                         break;
 289                 case Opt_cachetag:
 290 #ifdef CONFIG_9P_FSCACHE
 291                         kfree(v9ses->cachetag);
 292                         v9ses->cachetag = match_strdup(&args[0]);
 293                         if (!v9ses->cachetag) {
 294                                 ret = -ENOMEM;
 295                                 goto free_and_return;
 296                         }
 297 #endif
 298                         break;
 299                 case Opt_cache:
 300                         s = match_strdup(&args[0]);
 301                         if (!s) {
 302                                 ret = -ENOMEM;
 303                                 p9_debug(P9_DEBUG_ERROR,
 304                                          "problem allocating copy of cache arg\n");
 305                                 goto free_and_return;
 306                         }
 307                         r = get_cache_mode(s);
 308                         if (r < 0)
 309                                 ret = r;
 310                         else
 311                                 v9ses->cache = r;
 312
 313                         kfree(s);
 314                         break;
 315
 316                 case Opt_access:
 317                         s = match_strdup(&args[0]);
 318                         if (!s) {
 319                                 ret = -ENOMEM;
 320                                 p9_debug(P9_DEBUG_ERROR,
 321                                          "problem allocating copy of access arg\n");
 322                                 goto free_and_return;
 323                         }
 324
 325                         v9ses->flags &= ~V9FS_ACCESS_MASK;
 326                         if (strcmp(s, "user") == 0)
 327                                 v9ses->flags |= V9FS_ACCESS_USER;
 328                         else if (strcmp(s, "any") == 0)
 329                                 v9ses->flags |= V9FS_ACCESS_ANY;
 330                         else if (strcmp(s, "client") == 0) {
 331                                 v9ses->flags |= V9FS_ACCESS_CLIENT;
 332                         } else {
 333                                 uid_t uid;
 334                                 v9ses->flags |= V9FS_ACCESS_SINGLE;
 335                                 uid = simple_strtoul(s, &e, 10);
 336                                 if (*e != '\0') {
 337                                         ret = -EINVAL;
 338                                         pr_info("Unknown access argument %s\n",
 339                                                 s);
 340                                         kfree(s);
 341                                         continue;
 342                                 }
 343                                 v9ses->uid = make_kuid(current_user_ns(), uid);
 344                                 if (!uid_valid(v9ses->uid)) {
 345                                         ret = -EINVAL;
 346                                         pr_info("Uknown uid %s\n", s);
 347                                 }
 348                         }
 349
 350                         kfree(s);
 351                         break;
 352
 353                 case Opt_posixacl:
 354 #ifdef CONFIG_9P_FS_POSIX_ACL
 355                         v9ses->flags |= V9FS_POSIX_ACL;
 356 #else
 357                         p9_debug(P9_DEBUG_ERROR,
 358                                  "Not defined CONFIG_9P_FS_POSIX_ACL. Ignoring posixacl option\n");
 359 #endif
 360                         break;
 361
 362                 default:
 363                         continue;
 364                 }
 365         }
 366
 367 free_and_return:
 368         kfree(tmp_options);
 369 fail_option_alloc:
 370         return ret;
 371 }
 372
 373 /**
 374  * v9fs_session_init - initialize session
 375  * @v9ses: session information structure
 376  * @dev_name: device being mounted
 377  * @data: options
 378  *
 379  */
 380
 381 struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
 382                   const char *dev_name, char *data)
 383 {
 384         struct p9_fid *fid;
 385         int rc = -ENOMEM;
 386
 387         v9ses->uname = kstrdup(V9FS_DEFUSER, GFP_KERNEL);
 388         if (!v9ses->uname)
 389                 goto err_names;
 390
 391         v9ses->aname = kstrdup(V9FS_DEFANAME, GFP_KERNEL);
 392         if (!v9ses->aname)
 393                 goto err_names;
 394         init_rwsem(&v9ses->rename_sem);
 395
 396         v9ses->uid = INVALID_UID;
 397         v9ses->dfltuid = V9FS_DEFUID;
 398         v9ses->dfltgid = V9FS_DEFGID;
 399
 400         v9ses->clnt = p9_client_create(dev_name, data);
 401         if (IS_ERR(v9ses->clnt)) {
 402                 rc = PTR_ERR(v9ses->clnt);
 403                 p9_debug(P9_DEBUG_ERROR, "problem initializing 9p client\n");
 404                 goto err_names;
 405         }
 406
 407         v9ses->flags = V9FS_ACCESS_USER;
 408
 409         if (p9_is_proto_dotl(v9ses->clnt)) {
 410                 v9ses->flags = V9FS_ACCESS_CLIENT;
 411                 v9ses->flags |= V9FS_PROTO_2000L;
 412         } else if (p9_is_proto_dotu(v9ses->clnt)) {
 413                 v9ses->flags |= V9FS_PROTO_2000U;
 414         }
 415
 416         rc = v9fs_parse_options(v9ses, data);
 417         if (rc < 0)
 418                 goto err_clnt;
 419
 420         v9ses->maxdata = v9ses->clnt->msize - P9_IOHDRSZ;
 421
 422         if (!v9fs_proto_dotl(v9ses) &&
 423             ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
 424                 /*
 425                  * We support ACCESS_CLIENT only for dotl.
 426                  * Fall back to ACCESS_USER
 427                  */
 428                 v9ses->flags &= ~V9FS_ACCESS_MASK;
 429                 v9ses->flags |= V9FS_ACCESS_USER;
 430         }
 431         /*FIXME !! */
 432         /* for legacy mode, fall back to V9FS_ACCESS_ANY */
 433         if (!(v9fs_proto_dotu(v9ses) || v9fs_proto_dotl(v9ses)) &&
 434                 ((v9ses->flags&V9FS_ACCESS_MASK) == V9FS_ACCESS_USER)) {
 435
 436                 v9ses->flags &= ~V9FS_ACCESS_MASK;
 437                 v9ses->flags |= V9FS_ACCESS_ANY;
 438                 v9ses->uid = INVALID_UID;
 439         }
 440         if (!v9fs_proto_dotl(v9ses) ||
 441                 !((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
 442                 /*
 443                  * We support ACL checks on clinet only if the protocol is
 444                  * 9P2000.L and access is V9FS_ACCESS_CLIENT.
 445                  */
 446                 v9ses->flags &= ~V9FS_ACL_MASK;
 447         }
 448
 449         fid = p9_client_attach(v9ses->clnt, NULL, v9ses->uname, INVALID_UID,
 450                                                         v9ses->aname);
 451         if (IS_ERR(fid)) {
 452                 rc = PTR_ERR(fid);
 453                 p9_debug(P9_DEBUG_ERROR, "cannot attach\n");
 454                 goto err_clnt;
 455         }
 456
 457         if ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_SINGLE)
 458                 fid->uid = v9ses->uid;
 459         else
 460                 fid->uid = INVALID_UID;
 461
 462 #ifdef CONFIG_9P_FSCACHE
 463         /* register the session for caching */
 464         v9fs_cache_session_get_cookie(v9ses);
 465 #endif
 466         spin_lock(&v9fs_sessionlist_lock);
 467         list_add(&v9ses->slist, &v9fs_sessionlist);
 468         spin_unlock(&v9fs_sessionlist_lock);
 469
 470         return fid;
 471
 472 err_clnt:
 473 #ifdef CONFIG_9P_FSCACHE
 474         kfree(v9ses->cachetag);
 475 #endif
 476         p9_client_destroy(v9ses->clnt);
 477 err_names:
 478         kfree(v9ses->uname);
 479         kfree(v9ses->aname);
 480         return ERR_PTR(rc);
 481 }
 482
 483 /**
 484  * v9fs_session_close - shutdown a session
 485  * @v9ses: session information structure
 486  *
 487  */
 488
 489 void v9fs_session_close(struct v9fs_session_info *v9ses)
 490 {
 491         if (v9ses->clnt) {
 492                 p9_client_destroy(v9ses->clnt);
 493                 v9ses->clnt = NULL;
 494         }
 495
 496 #ifdef CONFIG_9P_FSCACHE
 497         if (v9ses->fscache) {
 498                 v9fs_cache_session_put_cookie(v9ses);
 499                 kfree(v9ses->cachetag);
 500         }
 501 #endif
 502         kfree(v9ses->uname);
 503         kfree(v9ses->aname);
 504
 505         spin_lock(&v9fs_sessionlist_lock);
 506         list_del(&v9ses->slist);
 507         spin_unlock(&v9fs_sessionlist_lock);
 508 }
 509
 510 /**
 511  * v9fs_session_cancel - terminate a session
 512  * @v9ses: session to terminate
 513  *
 514  * mark transport as disconnected and cancel all pending requests.
 515  */
 516
 517 void v9fs_session_cancel(struct v9fs_session_info *v9ses) {
 518         p9_debug(P9_DEBUG_ERROR, "cancel session %p\n", v9ses);
 519         p9_client_disconnect(v9ses->clnt);
 520 }
 521
 522 /**
 523  * v9fs_session_begin_cancel - Begin terminate of a session
 524  * @v9ses: session to terminate
 525  *
 526  * After this call we don't allow any request other than clunk.
 527  */
 528
 529 void v9fs_session_begin_cancel(struct v9fs_session_info *v9ses)
 530 {
 531         p9_debug(P9_DEBUG_ERROR, "begin cancel session %p\n", v9ses);
 532         p9_client_begin_disconnect(v9ses->clnt);
 533 }
 534
 535 extern int v9fs_error_init(void);
 536
 537 static struct kobject *v9fs_kobj;
 538
 539 #ifdef CONFIG_9P_FSCACHE
 540 /**
 541  * caches_show - list caches associated with a session
 542  *
 543  * Returns the size of buffer written.
 544  */
 545
 546 static ssize_t caches_show(struct kobject *kobj,
 547                            struct kobj_attribute *attr,
 548                            char *buf)
 549 {
 550         ssize_t n = 0, count = 0, limit = PAGE_SIZE;
 551         struct v9fs_session_info *v9ses;
 552
 553         spin_lock(&v9fs_sessionlist_lock);
 554         list_for_each_entry(v9ses, &v9fs_sessionlist, slist) {
 555                 if (v9ses->cachetag) {
 556                         n = snprintf(buf, limit, "%s\n", v9ses->cachetag);
 557                         if (n < 0) {
 558                                 count = n;
 559                                 break;
 560                         }
 561
 562                         count += n;
 563                         limit -= n;
 564                 }
 565         }
 566
 567         spin_unlock(&v9fs_sessionlist_lock);
 568         return count;
 569 }
 570
 571 static struct kobj_attribute v9fs_attr_cache = __ATTR_RO(caches);
 572 #endif /* CONFIG_9P_FSCACHE */
 573
 574 static struct attribute *v9fs_attrs[] = {
 575 #ifdef CONFIG_9P_FSCACHE
 576         &v9fs_attr_cache.attr,
 577 #endif
 578         NULL,
 579 };
 580
 581 static struct attribute_group v9fs_attr_group = {
 582         .attrs = v9fs_attrs,
 583 };
 584
 585 /**
 586  * v9fs_sysfs_init - Initialize the v9fs sysfs interface
 587  *
 588  */
 589
 590 static int __init v9fs_sysfs_init(void)
 591 {
 592         v9fs_kobj = kobject_create_and_add("9p", fs_kobj);
 593         if (!v9fs_kobj)
 594                 return -ENOMEM;
 595
 596         if (sysfs_create_group(v9fs_kobj, &v9fs_attr_group)) {
 597                 kobject_put(v9fs_kobj);
 598                 return -ENOMEM;
 599         }
 600
 601         return 0;
 602 }
 603
 604 /**
 605  * v9fs_sysfs_cleanup - Unregister the v9fs sysfs interface
 606  *
 607  */
 608
 609 static void v9fs_sysfs_cleanup(void)
 610 {
 611         sysfs_remove_group(v9fs_kobj, &v9fs_attr_group);
 612         kobject_put(v9fs_kobj);
 613 }
 614
 615 static void v9fs_inode_init_once(void *foo)
 616 {
 617         struct v9fs_inode *v9inode = (struct v9fs_inode *)foo;
 618 #ifdef CONFIG_9P_FSCACHE
 619         v9inode->fscache = NULL;
 620 #endif
 621         memset(&v9inode->qid, 0, sizeof(v9inode->qid));
 622         inode_init_once(&v9inode->vfs_inode);
 623 }
 624
 625 /**
 626  * v9fs_init_inode_cache - initialize a cache for 9P
 627  * Returns 0 on success.
 628  */
 629 static int v9fs_init_inode_cache(void)
 630 {
 631         v9fs_inode_cache = kmem_cache_create("v9fs_inode_cache",
 632                                           sizeof(struct v9fs_inode),
 633                                           0, (SLAB_RECLAIM_ACCOUNT|
 634                                               SLAB_MEM_SPREAD|SLAB_ACCOUNT),
 635                                           v9fs_inode_init_once);
 636         if (!v9fs_inode_cache)
 637                 return -ENOMEM;
 638
 639         return 0;
 640 }
 641
 642 /**
 643  * v9fs_destroy_inode_cache - destroy the cache of 9P inode
 644  *
 645  */
 646 static void v9fs_destroy_inode_cache(void)
 647 {
 648         /*
 649          * Make sure all delayed rcu free inodes are flushed before we
 650          * destroy cache.
 651          */
 652         rcu_barrier();
 653         kmem_cache_destroy(v9fs_inode_cache);
 654 }
 655
 656 static int v9fs_cache_register(void)
 657 {
 658         int ret;
 659         ret = v9fs_init_inode_cache();
 660         if (ret < 0)
 661                 return ret;
 662 #ifdef CONFIG_9P_FSCACHE
 663         ret = fscache_register_netfs(&v9fs_cache_netfs);
 664         if (ret < 0)
 665                 v9fs_destroy_inode_cache();
 666 #endif
 667         return ret;
 668 }
 669
 670 static void v9fs_cache_unregister(void)
 671 {
 672         v9fs_destroy_inode_cache();
 673 #ifdef CONFIG_9P_FSCACHE
 674         fscache_unregister_netfs(&v9fs_cache_netfs);
 675 #endif
 676 }
 677
 678 /**
 679  * init_v9fs - Initialize module
 680  *
 681  */
 682
 683 static int __init init_v9fs(void)
 684 {
 685         int err;
 686         pr_info("Installing v9fs 9p2000 file system support\n");
 687         /* TODO: Setup list of registered trasnport modules */
 688
 689         err = v9fs_cache_register();
 690         if (err < 0) {
 691                 pr_err("Failed to register v9fs for caching\n");
 692                 return err;
 693         }
 694
 695         err = v9fs_sysfs_init();
 696         if (err < 0) {
 697                 pr_err("Failed to register with sysfs\n");
 698                 goto out_cache;
 699         }
 700         err = register_filesystem(&v9fs_fs_type);
 701         if (err < 0) {
 702                 pr_err("Failed to register filesystem\n");
 703                 goto out_sysfs_cleanup;
 704         }
 705
 706         return 0;
 707
 708 out_sysfs_cleanup:
 709         v9fs_sysfs_cleanup();
 710
 711 out_cache:
 712         v9fs_cache_unregister();
 713
 714         return err;
 715 }
 716
 717 /**
 718  * exit_v9fs - shutdown module
 719  *
 720  */
 721
 722 static void __exit exit_v9fs(void)
 723 {
 724         v9fs_sysfs_cleanup();
 725         v9fs_cache_unregister();
 726         unregister_filesystem(&v9fs_fs_type);
 727 }
 728
 729 module_init(init_v9fs)
 730 module_exit(exit_v9fs)
 731
 732 MODULE_AUTHOR("Latchesar Ionkov <lucho@ionkov.net>");
 733 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
 734 MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
 735 MODULE_LICENSE("GPL");