fs/9p/v9fs.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *  linux/fs/9p/v9fs.c
   4  *
   5  *  This file contains functions assisting in mapping VFS to 9P2000
   6  *
   7  *  Copyright (C) 2004-2008 by Eric Van Hensbergen <ericvh@gmail.com>
   8  *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
   9  */
  10
  11 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  12
  13 #include <linux/module.h>
  14 #include <linux/errno.h>
  15 #include <linux/fs.h>
  16 #include <linux/sched.h>
  17 #include <linux/cred.h>
  18 #include <linux/parser.h>
  19 #include <linux/idr.h>
  20 #include <linux/slab.h>
  21 #include <linux/seq_file.h>
  22 #include <net/9p/9p.h>
  23 #include <net/9p/client.h>
  24 #include <net/9p/transport.h>
  25 #include "v9fs.h"
  26 #include "v9fs_vfs.h"
  27 #include "cache.h"
  28
  29 static DEFINE_SPINLOCK(v9fs_sessionlist_lock);
  30 static LIST_HEAD(v9fs_sessionlist);
  31 struct kmem_cache *v9fs_inode_cache;
  32
  33 /*
  34  * Option Parsing (code inspired by NFS code)
  35  *  NOTE: each transport will parse its own options
  36  */
  37
  38 enum {
  39         /* Options that take integer arguments */
  40         Opt_debug, Opt_dfltuid, Opt_dfltgid, Opt_afid,
  41         /* String options */
  42         Opt_uname, Opt_remotename, Opt_cache, Opt_cachetag,
  43         /* Options that take no arguments */
  44         Opt_nodevmap,
  45         /* Cache options */
  46         Opt_cache_loose, Opt_fscache, Opt_mmap,
  47         /* Access options */
  48         Opt_access, Opt_posixacl,
  49         /* Lock timeout option */
  50         Opt_locktimeout,
  51         /* Error token */
  52         Opt_err
  53 };
  54
  55 static const match_table_t tokens = {
  56         {Opt_debug, "debug=%x"},
  57         {Opt_dfltuid, "dfltuid=%u"},
  58         {Opt_dfltgid, "dfltgid=%u"},
  59         {Opt_afid, "afid=%u"},
  60         {Opt_uname, "uname=%s"},
  61         {Opt_remotename, "aname=%s"},
  62         {Opt_nodevmap, "nodevmap"},
  63         {Opt_cache, "cache=%s"},
  64         {Opt_cache_loose, "loose"},
  65         {Opt_fscache, "fscache"},
  66         {Opt_mmap, "mmap"},
  67         {Opt_cachetag, "cachetag=%s"},
  68         {Opt_access, "access=%s"},
  69         {Opt_posixacl, "posixacl"},
  70         {Opt_locktimeout, "locktimeout=%u"},
  71         {Opt_err, NULL}
  72 };
  73
  74 static const char *const v9fs_cache_modes[nr__p9_cache_modes] = {
  75         [CACHE_NONE]    = "none",
  76         [CACHE_MMAP]    = "mmap",
  77         [CACHE_LOOSE]   = "loose",
  78         [CACHE_FSCACHE] = "fscache",
  79 };
  80
  81 /* Interpret mount options for cache mode */
  82 static int get_cache_mode(char *s)
  83 {
  84         int version = -EINVAL;
  85
  86         if (!strcmp(s, "loose")) {
  87                 version = CACHE_LOOSE;
  88                 p9_debug(P9_DEBUG_9P, "Cache mode: loose\n");
  89         } else if (!strcmp(s, "fscache")) {
  90                 version = CACHE_FSCACHE;
  91                 p9_debug(P9_DEBUG_9P, "Cache mode: fscache\n");
  92         } else if (!strcmp(s, "mmap")) {
  93                 version = CACHE_MMAP;
  94                 p9_debug(P9_DEBUG_9P, "Cache mode: mmap\n");
  95         } else if (!strcmp(s, "none")) {
  96                 version = CACHE_NONE;
  97                 p9_debug(P9_DEBUG_9P, "Cache mode: none\n");
  98         } else
  99                 pr_info("Unknown Cache mode %s\n", s);
 100         return version;
 101 }
 102
 103 /*
 104  * Display the mount options in /proc/mounts.
 105  */
 106 int v9fs_show_options(struct seq_file *m, struct dentry *root)
 107 {
 108         struct v9fs_session_info *v9ses = root->d_sb->s_fs_info;
 109
 110         if (v9ses->debug)
 111                 seq_printf(m, ",debug=%x", v9ses->debug);
 112         if (!uid_eq(v9ses->dfltuid, V9FS_DEFUID))
 113                 seq_printf(m, ",dfltuid=%u",
 114                            from_kuid_munged(&init_user_ns, v9ses->dfltuid));
 115         if (!gid_eq(v9ses->dfltgid, V9FS_DEFGID))
 116                 seq_printf(m, ",dfltgid=%u",
 117                            from_kgid_munged(&init_user_ns, v9ses->dfltgid));
 118         if (v9ses->afid != ~0)
 119                 seq_printf(m, ",afid=%u", v9ses->afid);
 120         if (strcmp(v9ses->uname, V9FS_DEFUSER) != 0)
 121                 seq_printf(m, ",uname=%s", v9ses->uname);
 122         if (strcmp(v9ses->aname, V9FS_DEFANAME) != 0)
 123                 seq_printf(m, ",aname=%s", v9ses->aname);
 124         if (v9ses->nodev)
 125                 seq_puts(m, ",nodevmap");
 126         if (v9ses->cache)
 127                 seq_printf(m, ",%s", v9fs_cache_modes[v9ses->cache]);
 128 #ifdef CONFIG_9P_FSCACHE
 129         if (v9ses->cachetag && v9ses->cache == CACHE_FSCACHE)
 130                 seq_printf(m, ",cachetag=%s", v9ses->cachetag);
 131 #endif
 132
 133         switch (v9ses->flags & V9FS_ACCESS_MASK) {
 134         case V9FS_ACCESS_USER:
 135                 seq_puts(m, ",access=user");
 136                 break;
 137         case V9FS_ACCESS_ANY:
 138                 seq_puts(m, ",access=any");
 139                 break;
 140         case V9FS_ACCESS_CLIENT:
 141                 seq_puts(m, ",access=client");
 142                 break;
 143         case V9FS_ACCESS_SINGLE:
 144                 seq_printf(m, ",access=%u",
 145                            from_kuid_munged(&init_user_ns, v9ses->uid));
 146                 break;
 147         }
 148
 149         if (v9ses->flags & V9FS_POSIX_ACL)
 150                 seq_puts(m, ",posixacl");
 151
 152         return p9_show_client_options(m, v9ses->clnt);
 153 }
 154
 155 /**
 156  * v9fs_parse_options - parse mount options into session structure
 157  * @v9ses: existing v9fs session information
 158  * @opts: The mount option string
 159  *
 160  * Return 0 upon success, -ERRNO upon failure.
 161  */
 162
 163 static int v9fs_parse_options(struct v9fs_session_info *v9ses, char *opts)
 164 {
 165         char *options, *tmp_options;
 166         substring_t args[MAX_OPT_ARGS];
 167         char *p;
 168         int option = 0;
 169         char *s, *e;
 170         int ret = 0;
 171
 172         /* setup defaults */
 173         v9ses->afid = ~0;
 174         v9ses->debug = 0;
 175         v9ses->cache = CACHE_NONE;
 176 #ifdef CONFIG_9P_FSCACHE
 177         v9ses->cachetag = NULL;
 178 #endif
 179         v9ses->session_lock_timeout = P9_LOCK_TIMEOUT;
 180
 181         if (!opts)
 182                 return 0;
 183
 184         tmp_options = kstrdup(opts, GFP_KERNEL);
 185         if (!tmp_options) {
 186                 ret = -ENOMEM;
 187                 goto fail_option_alloc;
 188         }
 189         options = tmp_options;
 190
 191         while ((p = strsep(&options, ",")) != NULL) {
 192                 int token, r;
 193
 194                 if (!*p)
 195                         continue;
 196
 197                 token = match_token(p, tokens, args);
 198                 switch (token) {
 199                 case Opt_debug:
 200                         r = match_int(&args[0], &option);
 201                         if (r < 0) {
 202                                 p9_debug(P9_DEBUG_ERROR,
 203                                          "integer field, but no integer?\n");
 204                                 ret = r;
 205                         } else {
 206                                 v9ses->debug = option;
 207 #ifdef CONFIG_NET_9P_DEBUG
 208                                 p9_debug_level = option;
 209 #endif
 210                         }
 211                         break;
 212
 213                 case Opt_dfltuid:
 214                         r = match_int(&args[0], &option);
 215                         if (r < 0) {
 216                                 p9_debug(P9_DEBUG_ERROR,
 217                                          "integer field, but no integer?\n");
 218                                 ret = r;
 219                                 continue;
 220                         }
 221                         v9ses->dfltuid = make_kuid(current_user_ns(), option);
 222                         if (!uid_valid(v9ses->dfltuid)) {
 223                                 p9_debug(P9_DEBUG_ERROR,
 224                                          "uid field, but not a uid?\n");
 225                                 ret = -EINVAL;
 226                         }
 227                         break;
 228                 case Opt_dfltgid:
 229                         r = match_int(&args[0], &option);
 230                         if (r < 0) {
 231                                 p9_debug(P9_DEBUG_ERROR,
 232                                          "integer field, but no integer?\n");
 233                                 ret = r;
 234                                 continue;
 235                         }
 236                         v9ses->dfltgid = make_kgid(current_user_ns(), option);
 237                         if (!gid_valid(v9ses->dfltgid)) {
 238                                 p9_debug(P9_DEBUG_ERROR,
 239                                          "gid field, but not a gid?\n");
 240                                 ret = -EINVAL;
 241                         }
 242                         break;
 243                 case Opt_afid:
 244                         r = match_int(&args[0], &option);
 245                         if (r < 0) {
 246                                 p9_debug(P9_DEBUG_ERROR,
 247                                          "integer field, but no integer?\n");
 248                                 ret = r;
 249                         } else {
 250                                 v9ses->afid = option;
 251                         }
 252                         break;
 253                 case Opt_uname:
 254                         kfree(v9ses->uname);
 255                         v9ses->uname = match_strdup(&args[0]);
 256                         if (!v9ses->uname) {
 257                                 ret = -ENOMEM;
 258                                 goto free_and_return;
 259                         }
 260                         break;
 261                 case Opt_remotename:
 262                         kfree(v9ses->aname);
 263                         v9ses->aname = match_strdup(&args[0]);
 264                         if (!v9ses->aname) {
 265                                 ret = -ENOMEM;
 266                                 goto free_and_return;
 267                         }
 268                         break;
 269                 case Opt_nodevmap:
 270                         v9ses->nodev = 1;
 271                         break;
 272                 case Opt_cache_loose:
 273                         v9ses->cache = CACHE_LOOSE;
 274                         break;
 275                 case Opt_fscache:
 276                         v9ses->cache = CACHE_FSCACHE;
 277                         break;
 278                 case Opt_mmap:
 279                         v9ses->cache = CACHE_MMAP;
 280                         break;
 281                 case Opt_cachetag:
 282 #ifdef CONFIG_9P_FSCACHE
 283                         kfree(v9ses->cachetag);
 284                         v9ses->cachetag = match_strdup(&args[0]);
 285                         if (!v9ses->cachetag) {
 286                                 ret = -ENOMEM;
 287                                 goto free_and_return;
 288                         }
 289 #endif
 290                         break;
 291                 case Opt_cache:
 292                         s = match_strdup(&args[0]);
 293                         if (!s) {
 294                                 ret = -ENOMEM;
 295                                 p9_debug(P9_DEBUG_ERROR,
 296                                          "problem allocating copy of cache arg\n");
 297                                 goto free_and_return;
 298                         }
 299                         r = get_cache_mode(s);
 300                         if (r < 0)
 301                                 ret = r;
 302                         else
 303                                 v9ses->cache = r;
 304
 305                         kfree(s);
 306                         break;
 307
 308                 case Opt_access:
 309                         s = match_strdup(&args[0]);
 310                         if (!s) {
 311                                 ret = -ENOMEM;
 312                                 p9_debug(P9_DEBUG_ERROR,
 313                                          "problem allocating copy of access arg\n");
 314                                 goto free_and_return;
 315                         }
 316
 317                         v9ses->flags &= ~V9FS_ACCESS_MASK;
 318                         if (strcmp(s, "user") == 0)
 319                                 v9ses->flags |= V9FS_ACCESS_USER;
 320                         else if (strcmp(s, "any") == 0)
 321                                 v9ses->flags |= V9FS_ACCESS_ANY;
 322                         else if (strcmp(s, "client") == 0) {
 323                                 v9ses->flags |= V9FS_ACCESS_CLIENT;
 324                         } else {
 325                                 uid_t uid;
 326                                 v9ses->flags |= V9FS_ACCESS_SINGLE;
 327                                 uid = simple_strtoul(s, &e, 10);
 328                                 if (*e != '\0') {
 329                                         ret = -EINVAL;
 330                                         pr_info("Unknown access argument %s\n",
 331                                                 s);
 332                                         kfree(s);
 333                                         continue;
 334                                 }
 335                                 v9ses->uid = make_kuid(current_user_ns(), uid);
 336                                 if (!uid_valid(v9ses->uid)) {
 337                                         ret = -EINVAL;
 338                                         pr_info("Unknown uid %s\n", s);
 339                                 }
 340                         }
 341
 342                         kfree(s);
 343                         break;
 344
 345                 case Opt_posixacl:
 346 #ifdef CONFIG_9P_FS_POSIX_ACL
 347                         v9ses->flags |= V9FS_POSIX_ACL;
 348 #else
 349                         p9_debug(P9_DEBUG_ERROR,
 350                                  "Not defined CONFIG_9P_FS_POSIX_ACL. Ignoring posixacl option\n");
 351 #endif
 352                         break;
 353
 354                 case Opt_locktimeout:
 355                         r = match_int(&args[0], &option);
 356                         if (r < 0) {
 357                                 p9_debug(P9_DEBUG_ERROR,
 358                                          "integer field, but no integer?\n");
 359                                 ret = r;
 360                                 continue;
 361                         }
 362                         if (option < 1) {
 363                                 p9_debug(P9_DEBUG_ERROR,
 364                                          "locktimeout must be a greater than zero integer.\n");
 365                                 ret = -EINVAL;
 366                                 continue;
 367                         }
 368                         v9ses->session_lock_timeout = (long)option * HZ;
 369                         break;
 370
 371                 default:
 372                         continue;
 373                 }
 374         }
 375
 376 free_and_return:
 377         kfree(tmp_options);
 378 fail_option_alloc:
 379         return ret;
 380 }
 381
 382 /**
 383  * v9fs_session_init - initialize session
 384  * @v9ses: session information structure
 385  * @dev_name: device being mounted
 386  * @data: options
 387  *
 388  */
 389
 390 struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
 391                   const char *dev_name, char *data)
 392 {
 393         struct p9_fid *fid;
 394         int rc = -ENOMEM;
 395
 396         v9ses->uname = kstrdup(V9FS_DEFUSER, GFP_KERNEL);
 397         if (!v9ses->uname)
 398                 goto err_names;
 399
 400         v9ses->aname = kstrdup(V9FS_DEFANAME, GFP_KERNEL);
 401         if (!v9ses->aname)
 402                 goto err_names;
 403         init_rwsem(&v9ses->rename_sem);
 404
 405         v9ses->uid = INVALID_UID;
 406         v9ses->dfltuid = V9FS_DEFUID;
 407         v9ses->dfltgid = V9FS_DEFGID;
 408
 409         v9ses->clnt = p9_client_create(dev_name, data);
 410         if (IS_ERR(v9ses->clnt)) {
 411                 rc = PTR_ERR(v9ses->clnt);
 412                 p9_debug(P9_DEBUG_ERROR, "problem initializing 9p client\n");
 413                 goto err_names;
 414         }
 415
 416         v9ses->flags = V9FS_ACCESS_USER;
 417
 418         if (p9_is_proto_dotl(v9ses->clnt)) {
 419                 v9ses->flags = V9FS_ACCESS_CLIENT;
 420                 v9ses->flags |= V9FS_PROTO_2000L;
 421         } else if (p9_is_proto_dotu(v9ses->clnt)) {
 422                 v9ses->flags |= V9FS_PROTO_2000U;
 423         }
 424
 425         rc = v9fs_parse_options(v9ses, data);
 426         if (rc < 0)
 427                 goto err_clnt;
 428
 429         v9ses->maxdata = v9ses->clnt->msize - P9_IOHDRSZ;
 430
 431         if (!v9fs_proto_dotl(v9ses) &&
 432             ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
 433                 /*
 434                  * We support ACCESS_CLIENT only for dotl.
 435                  * Fall back to ACCESS_USER
 436                  */
 437                 v9ses->flags &= ~V9FS_ACCESS_MASK;
 438                 v9ses->flags |= V9FS_ACCESS_USER;
 439         }
 440         /*FIXME !! */
 441         /* for legacy mode, fall back to V9FS_ACCESS_ANY */
 442         if (!(v9fs_proto_dotu(v9ses) || v9fs_proto_dotl(v9ses)) &&
 443                 ((v9ses->flags&V9FS_ACCESS_MASK) == V9FS_ACCESS_USER)) {
 444
 445                 v9ses->flags &= ~V9FS_ACCESS_MASK;
 446                 v9ses->flags |= V9FS_ACCESS_ANY;
 447                 v9ses->uid = INVALID_UID;
 448         }
 449         if (!v9fs_proto_dotl(v9ses) ||
 450                 !((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
 451                 /*
 452                  * We support ACL checks on clinet only if the protocol is
 453                  * 9P2000.L and access is V9FS_ACCESS_CLIENT.
 454                  */
 455                 v9ses->flags &= ~V9FS_ACL_MASK;
 456         }
 457
 458         fid = p9_client_attach(v9ses->clnt, NULL, v9ses->uname, INVALID_UID,
 459                                                         v9ses->aname);
 460         if (IS_ERR(fid)) {
 461                 rc = PTR_ERR(fid);
 462                 p9_debug(P9_DEBUG_ERROR, "cannot attach\n");
 463                 goto err_clnt;
 464         }
 465
 466         if ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_SINGLE)
 467                 fid->uid = v9ses->uid;
 468         else
 469                 fid->uid = INVALID_UID;
 470
 471 #ifdef CONFIG_9P_FSCACHE
 472         /* register the session for caching */
 473         v9fs_cache_session_get_cookie(v9ses);
 474 #endif
 475         spin_lock(&v9fs_sessionlist_lock);
 476         list_add(&v9ses->slist, &v9fs_sessionlist);
 477         spin_unlock(&v9fs_sessionlist_lock);
 478
 479         return fid;
 480
 481 err_clnt:
 482 #ifdef CONFIG_9P_FSCACHE
 483         kfree(v9ses->cachetag);
 484 #endif
 485         p9_client_destroy(v9ses->clnt);
 486 err_names:
 487         kfree(v9ses->uname);
 488         kfree(v9ses->aname);
 489         return ERR_PTR(rc);
 490 }
 491
 492 /**
 493  * v9fs_session_close - shutdown a session
 494  * @v9ses: session information structure
 495  *
 496  */
 497
 498 void v9fs_session_close(struct v9fs_session_info *v9ses)
 499 {
 500         if (v9ses->clnt) {
 501                 p9_client_destroy(v9ses->clnt);
 502                 v9ses->clnt = NULL;
 503         }
 504
 505 #ifdef CONFIG_9P_FSCACHE
 506         if (v9ses->fscache)
 507                 v9fs_cache_session_put_cookie(v9ses);
 508         kfree(v9ses->cachetag);
 509 #endif
 510         kfree(v9ses->uname);
 511         kfree(v9ses->aname);
 512
 513         spin_lock(&v9fs_sessionlist_lock);
 514         list_del(&v9ses->slist);
 515         spin_unlock(&v9fs_sessionlist_lock);
 516 }
 517
 518 /**
 519  * v9fs_session_cancel - terminate a session
 520  * @v9ses: session to terminate
 521  *
 522  * mark transport as disconnected and cancel all pending requests.
 523  */
 524
 525 void v9fs_session_cancel(struct v9fs_session_info *v9ses) {
 526         p9_debug(P9_DEBUG_ERROR, "cancel session %p\n", v9ses);
 527         p9_client_disconnect(v9ses->clnt);
 528 }
 529
 530 /**
 531  * v9fs_session_begin_cancel - Begin terminate of a session
 532  * @v9ses: session to terminate
 533  *
 534  * After this call we don't allow any request other than clunk.
 535  */
 536
 537 void v9fs_session_begin_cancel(struct v9fs_session_info *v9ses)
 538 {
 539         p9_debug(P9_DEBUG_ERROR, "begin cancel session %p\n", v9ses);
 540         p9_client_begin_disconnect(v9ses->clnt);
 541 }
 542
 543 extern int v9fs_error_init(void);
 544
 545 static struct kobject *v9fs_kobj;
 546
 547 #ifdef CONFIG_9P_FSCACHE
 548 /*
 549  * List caches associated with a session
 550  */
 551 static ssize_t caches_show(struct kobject *kobj,
 552                            struct kobj_attribute *attr,
 553                            char *buf)
 554 {
 555         ssize_t n = 0, count = 0, limit = PAGE_SIZE;
 556         struct v9fs_session_info *v9ses;
 557
 558         spin_lock(&v9fs_sessionlist_lock);
 559         list_for_each_entry(v9ses, &v9fs_sessionlist, slist) {
 560                 if (v9ses->cachetag) {
 561                         n = snprintf(buf, limit, "%s\n", v9ses->cachetag);
 562                         if (n < 0) {
 563                                 count = n;
 564                                 break;
 565                         }
 566
 567                         count += n;
 568                         limit -= n;
 569                 }
 570         }
 571
 572         spin_unlock(&v9fs_sessionlist_lock);
 573         return count;
 574 }
 575
 576 static struct kobj_attribute v9fs_attr_cache = __ATTR_RO(caches);
 577 #endif /* CONFIG_9P_FSCACHE */
 578
 579 static struct attribute *v9fs_attrs[] = {
 580 #ifdef CONFIG_9P_FSCACHE
 581         &v9fs_attr_cache.attr,
 582 #endif
 583         NULL,
 584 };
 585
 586 static const struct attribute_group v9fs_attr_group = {
 587         .attrs = v9fs_attrs,
 588 };
 589
 590 /**
 591  * v9fs_sysfs_init - Initialize the v9fs sysfs interface
 592  *
 593  */
 594
 595 static int __init v9fs_sysfs_init(void)
 596 {
 597         v9fs_kobj = kobject_create_and_add("9p", fs_kobj);
 598         if (!v9fs_kobj)
 599                 return -ENOMEM;
 600
 601         if (sysfs_create_group(v9fs_kobj, &v9fs_attr_group)) {
 602                 kobject_put(v9fs_kobj);
 603                 return -ENOMEM;
 604         }
 605
 606         return 0;
 607 }
 608
 609 /**
 610  * v9fs_sysfs_cleanup - Unregister the v9fs sysfs interface
 611  *
 612  */
 613
 614 static void v9fs_sysfs_cleanup(void)
 615 {
 616         sysfs_remove_group(v9fs_kobj, &v9fs_attr_group);
 617         kobject_put(v9fs_kobj);
 618 }
 619
 620 static void v9fs_inode_init_once(void *foo)
 621 {
 622         struct v9fs_inode *v9inode = (struct v9fs_inode *)foo;
 623 #ifdef CONFIG_9P_FSCACHE
 624         v9inode->fscache = NULL;
 625 #endif
 626         memset(&v9inode->qid, 0, sizeof(v9inode->qid));
 627         inode_init_once(&v9inode->vfs_inode);
 628 }
 629
 630 /**
 631  * v9fs_init_inode_cache - initialize a cache for 9P
 632  * Returns 0 on success.
 633  */
 634 static int v9fs_init_inode_cache(void)
 635 {
 636         v9fs_inode_cache = kmem_cache_create("v9fs_inode_cache",
 637                                           sizeof(struct v9fs_inode),
 638                                           0, (SLAB_RECLAIM_ACCOUNT|
 639                                               SLAB_MEM_SPREAD|SLAB_ACCOUNT),
 640                                           v9fs_inode_init_once);
 641         if (!v9fs_inode_cache)
 642                 return -ENOMEM;
 643
 644         return 0;
 645 }
 646
 647 /**
 648  * v9fs_destroy_inode_cache - destroy the cache of 9P inode
 649  *
 650  */
 651 static void v9fs_destroy_inode_cache(void)
 652 {
 653         /*
 654          * Make sure all delayed rcu free inodes are flushed before we
 655          * destroy cache.
 656          */
 657         rcu_barrier();
 658         kmem_cache_destroy(v9fs_inode_cache);
 659 }
 660
 661 static int v9fs_cache_register(void)
 662 {
 663         int ret;
 664
 665         ret = v9fs_init_inode_cache();
 666         if (ret < 0)
 667                 return ret;
 668 #ifdef CONFIG_9P_FSCACHE
 669         ret = fscache_register_netfs(&v9fs_cache_netfs);
 670         if (ret < 0)
 671                 v9fs_destroy_inode_cache();
 672 #endif
 673         return ret;
 674 }
 675
 676 static void v9fs_cache_unregister(void)
 677 {
 678         v9fs_destroy_inode_cache();
 679 #ifdef CONFIG_9P_FSCACHE
 680         fscache_unregister_netfs(&v9fs_cache_netfs);
 681 #endif
 682 }
 683
 684 /**
 685  * init_v9fs - Initialize module
 686  *
 687  */
 688
 689 static int __init init_v9fs(void)
 690 {
 691         int err;
 692
 693         pr_info("Installing v9fs 9p2000 file system support\n");
 694         /* TODO: Setup list of registered trasnport modules */
 695
 696         err = v9fs_cache_register();
 697         if (err < 0) {
 698                 pr_err("Failed to register v9fs for caching\n");
 699                 return err;
 700         }
 701
 702         err = v9fs_sysfs_init();
 703         if (err < 0) {
 704                 pr_err("Failed to register with sysfs\n");
 705                 goto out_cache;
 706         }
 707         err = register_filesystem(&v9fs_fs_type);
 708         if (err < 0) {
 709                 pr_err("Failed to register filesystem\n");
 710                 goto out_sysfs_cleanup;
 711         }
 712
 713         return 0;
 714
 715 out_sysfs_cleanup:
 716         v9fs_sysfs_cleanup();
 717
 718 out_cache:
 719         v9fs_cache_unregister();
 720
 721         return err;
 722 }
 723
 724 /**
 725  * exit_v9fs - shutdown module
 726  *
 727  */
 728
 729 static void __exit exit_v9fs(void)
 730 {
 731         v9fs_sysfs_cleanup();
 732         v9fs_cache_unregister();
 733         unregister_filesystem(&v9fs_fs_type);
 734 }
 735
 736 module_init(init_v9fs)
 737 module_exit(exit_v9fs)
 738
 739 MODULE_AUTHOR("Latchesar Ionkov <lucho@ionkov.net>");
 740 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
 741 MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
 742 MODULE_LICENSE("GPL");