fs/9p/v9fs.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *  This file contains functions assisting in mapping VFS to 9P2000
   4  *
   5  *  Copyright (C) 2004-2008 by Eric Van Hensbergen <ericvh@gmail.com>
   6  *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
   7  */
   8
   9 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  10
  11 #include <linux/module.h>
  12 #include <linux/errno.h>
  13 #include <linux/fs.h>
  14 #include <linux/sched.h>
  15 #include <linux/cred.h>
  16 #include <linux/parser.h>
  17 #include <linux/idr.h>
  18 #include <linux/slab.h>
  19 #include <linux/seq_file.h>
  20 #include <net/9p/9p.h>
  21 #include <net/9p/client.h>
  22 #include <net/9p/transport.h>
  23 #include "v9fs.h"
  24 #include "v9fs_vfs.h"
  25 #include "cache.h"
  26
  27 static DEFINE_SPINLOCK(v9fs_sessionlist_lock);
  28 static LIST_HEAD(v9fs_sessionlist);
  29 struct kmem_cache *v9fs_inode_cache;
  30
  31 /*
  32  * Option Parsing (code inspired by NFS code)
  33  *  NOTE: each transport will parse its own options
  34  */
  35
  36 enum {
  37         /* Options that take integer arguments */
  38         Opt_debug, Opt_dfltuid, Opt_dfltgid, Opt_afid,
  39         /* String options */
  40         Opt_uname, Opt_remotename, Opt_cache, Opt_cachetag,
  41         /* Options that take no arguments */
  42         Opt_nodevmap,
  43         /* Cache options */
  44         Opt_cache_loose, Opt_fscache, Opt_mmap,
  45         /* Access options */
  46         Opt_access, Opt_posixacl,
  47         /* Lock timeout option */
  48         Opt_locktimeout,
  49         /* Error token */
  50         Opt_err
  51 };
  52
  53 static const match_table_t tokens = {
  54         {Opt_debug, "debug=%x"},
  55         {Opt_dfltuid, "dfltuid=%u"},
  56         {Opt_dfltgid, "dfltgid=%u"},
  57         {Opt_afid, "afid=%u"},
  58         {Opt_uname, "uname=%s"},
  59         {Opt_remotename, "aname=%s"},
  60         {Opt_nodevmap, "nodevmap"},
  61         {Opt_cache, "cache=%s"},
  62         {Opt_cache_loose, "loose"},
  63         {Opt_fscache, "fscache"},
  64         {Opt_mmap, "mmap"},
  65         {Opt_cachetag, "cachetag=%s"},
  66         {Opt_access, "access=%s"},
  67         {Opt_posixacl, "posixacl"},
  68         {Opt_locktimeout, "locktimeout=%u"},
  69         {Opt_err, NULL}
  70 };
  71
  72 static const char *const v9fs_cache_modes[nr__p9_cache_modes] = {
  73         [CACHE_NONE]    = "none",
  74         [CACHE_MMAP]    = "mmap",
  75         [CACHE_LOOSE]   = "loose",
  76         [CACHE_FSCACHE] = "fscache",
  77 };
  78
  79 /* Interpret mount options for cache mode */
  80 static int get_cache_mode(char *s)
  81 {
  82         int version = -EINVAL;
  83
  84         if (!strcmp(s, "loose")) {
  85                 version = CACHE_LOOSE;
  86                 p9_debug(P9_DEBUG_9P, "Cache mode: loose\n");
  87         } else if (!strcmp(s, "fscache")) {
  88                 version = CACHE_FSCACHE;
  89                 p9_debug(P9_DEBUG_9P, "Cache mode: fscache\n");
  90         } else if (!strcmp(s, "mmap")) {
  91                 version = CACHE_MMAP;
  92                 p9_debug(P9_DEBUG_9P, "Cache mode: mmap\n");
  93         } else if (!strcmp(s, "none")) {
  94                 version = CACHE_NONE;
  95                 p9_debug(P9_DEBUG_9P, "Cache mode: none\n");
  96         } else
  97                 pr_info("Unknown Cache mode %s\n", s);
  98         return version;
  99 }
 100
 101 /*
 102  * Display the mount options in /proc/mounts.
 103  */
 104 int v9fs_show_options(struct seq_file *m, struct dentry *root)
 105 {
 106         struct v9fs_session_info *v9ses = root->d_sb->s_fs_info;
 107
 108         if (v9ses->debug)
 109                 seq_printf(m, ",debug=%x", v9ses->debug);
 110         if (!uid_eq(v9ses->dfltuid, V9FS_DEFUID))
 111                 seq_printf(m, ",dfltuid=%u",
 112                            from_kuid_munged(&init_user_ns, v9ses->dfltuid));
 113         if (!gid_eq(v9ses->dfltgid, V9FS_DEFGID))
 114                 seq_printf(m, ",dfltgid=%u",
 115                            from_kgid_munged(&init_user_ns, v9ses->dfltgid));
 116         if (v9ses->afid != ~0)
 117                 seq_printf(m, ",afid=%u", v9ses->afid);
 118         if (strcmp(v9ses->uname, V9FS_DEFUSER) != 0)
 119                 seq_printf(m, ",uname=%s", v9ses->uname);
 120         if (strcmp(v9ses->aname, V9FS_DEFANAME) != 0)
 121                 seq_printf(m, ",aname=%s", v9ses->aname);
 122         if (v9ses->nodev)
 123                 seq_puts(m, ",nodevmap");
 124         if (v9ses->cache)
 125                 seq_printf(m, ",%s", v9fs_cache_modes[v9ses->cache]);
 126 #ifdef CONFIG_9P_FSCACHE
 127         if (v9ses->cachetag && v9ses->cache == CACHE_FSCACHE)
 128                 seq_printf(m, ",cachetag=%s", v9ses->cachetag);
 129 #endif
 130
 131         switch (v9ses->flags & V9FS_ACCESS_MASK) {
 132         case V9FS_ACCESS_USER:
 133                 seq_puts(m, ",access=user");
 134                 break;
 135         case V9FS_ACCESS_ANY:
 136                 seq_puts(m, ",access=any");
 137                 break;
 138         case V9FS_ACCESS_CLIENT:
 139                 seq_puts(m, ",access=client");
 140                 break;
 141         case V9FS_ACCESS_SINGLE:
 142                 seq_printf(m, ",access=%u",
 143                            from_kuid_munged(&init_user_ns, v9ses->uid));
 144                 break;
 145         }
 146
 147         if (v9ses->flags & V9FS_POSIX_ACL)
 148                 seq_puts(m, ",posixacl");
 149
 150         return p9_show_client_options(m, v9ses->clnt);
 151 }
 152
 153 /**
 154  * v9fs_parse_options - parse mount options into session structure
 155  * @v9ses: existing v9fs session information
 156  * @opts: The mount option string
 157  *
 158  * Return 0 upon success, -ERRNO upon failure.
 159  */
 160
 161 static int v9fs_parse_options(struct v9fs_session_info *v9ses, char *opts)
 162 {
 163         char *options, *tmp_options;
 164         substring_t args[MAX_OPT_ARGS];
 165         char *p;
 166         int option = 0;
 167         char *s;
 168         int ret = 0;
 169
 170         /* setup defaults */
 171         v9ses->afid = ~0;
 172         v9ses->debug = 0;
 173         v9ses->cache = CACHE_NONE;
 174 #ifdef CONFIG_9P_FSCACHE
 175         v9ses->cachetag = NULL;
 176 #endif
 177         v9ses->session_lock_timeout = P9_LOCK_TIMEOUT;
 178
 179         if (!opts)
 180                 return 0;
 181
 182         tmp_options = kstrdup(opts, GFP_KERNEL);
 183         if (!tmp_options) {
 184                 ret = -ENOMEM;
 185                 goto fail_option_alloc;
 186         }
 187         options = tmp_options;
 188
 189         while ((p = strsep(&options, ",")) != NULL) {
 190                 int token, r;
 191
 192                 if (!*p)
 193                         continue;
 194
 195                 token = match_token(p, tokens, args);
 196                 switch (token) {
 197                 case Opt_debug:
 198                         r = match_int(&args[0], &option);
 199                         if (r < 0) {
 200                                 p9_debug(P9_DEBUG_ERROR,
 201                                          "integer field, but no integer?\n");
 202                                 ret = r;
 203                         } else {
 204                                 v9ses->debug = option;
 205 #ifdef CONFIG_NET_9P_DEBUG
 206                                 p9_debug_level = option;
 207 #endif
 208                         }
 209                         break;
 210
 211                 case Opt_dfltuid:
 212                         r = match_int(&args[0], &option);
 213                         if (r < 0) {
 214                                 p9_debug(P9_DEBUG_ERROR,
 215                                          "integer field, but no integer?\n");
 216                                 ret = r;
 217                                 continue;
 218                         }
 219                         v9ses->dfltuid = make_kuid(current_user_ns(), option);
 220                         if (!uid_valid(v9ses->dfltuid)) {
 221                                 p9_debug(P9_DEBUG_ERROR,
 222                                          "uid field, but not a uid?\n");
 223                                 ret = -EINVAL;
 224                         }
 225                         break;
 226                 case Opt_dfltgid:
 227                         r = match_int(&args[0], &option);
 228                         if (r < 0) {
 229                                 p9_debug(P9_DEBUG_ERROR,
 230                                          "integer field, but no integer?\n");
 231                                 ret = r;
 232                                 continue;
 233                         }
 234                         v9ses->dfltgid = make_kgid(current_user_ns(), option);
 235                         if (!gid_valid(v9ses->dfltgid)) {
 236                                 p9_debug(P9_DEBUG_ERROR,
 237                                          "gid field, but not a gid?\n");
 238                                 ret = -EINVAL;
 239                         }
 240                         break;
 241                 case Opt_afid:
 242                         r = match_int(&args[0], &option);
 243                         if (r < 0) {
 244                                 p9_debug(P9_DEBUG_ERROR,
 245                                          "integer field, but no integer?\n");
 246                                 ret = r;
 247                         } else {
 248                                 v9ses->afid = option;
 249                         }
 250                         break;
 251                 case Opt_uname:
 252                         kfree(v9ses->uname);
 253                         v9ses->uname = match_strdup(&args[0]);
 254                         if (!v9ses->uname) {
 255                                 ret = -ENOMEM;
 256                                 goto free_and_return;
 257                         }
 258                         break;
 259                 case Opt_remotename:
 260                         kfree(v9ses->aname);
 261                         v9ses->aname = match_strdup(&args[0]);
 262                         if (!v9ses->aname) {
 263                                 ret = -ENOMEM;
 264                                 goto free_and_return;
 265                         }
 266                         break;
 267                 case Opt_nodevmap:
 268                         v9ses->nodev = 1;
 269                         break;
 270                 case Opt_cache_loose:
 271                         v9ses->cache = CACHE_LOOSE;
 272                         break;
 273                 case Opt_fscache:
 274                         v9ses->cache = CACHE_FSCACHE;
 275                         break;
 276                 case Opt_mmap:
 277                         v9ses->cache = CACHE_MMAP;
 278                         break;
 279                 case Opt_cachetag:
 280 #ifdef CONFIG_9P_FSCACHE
 281                         kfree(v9ses->cachetag);
 282                         v9ses->cachetag = match_strdup(&args[0]);
 283                         if (!v9ses->cachetag) {
 284                                 ret = -ENOMEM;
 285                                 goto free_and_return;
 286                         }
 287 #endif
 288                         break;
 289                 case Opt_cache:
 290                         s = match_strdup(&args[0]);
 291                         if (!s) {
 292                                 ret = -ENOMEM;
 293                                 p9_debug(P9_DEBUG_ERROR,
 294                                          "problem allocating copy of cache arg\n");
 295                                 goto free_and_return;
 296                         }
 297                         r = get_cache_mode(s);
 298                         if (r < 0)
 299                                 ret = r;
 300                         else
 301                                 v9ses->cache = r;
 302
 303                         kfree(s);
 304                         break;
 305
 306                 case Opt_access:
 307                         s = match_strdup(&args[0]);
 308                         if (!s) {
 309                                 ret = -ENOMEM;
 310                                 p9_debug(P9_DEBUG_ERROR,
 311                                          "problem allocating copy of access arg\n");
 312                                 goto free_and_return;
 313                         }
 314
 315                         v9ses->flags &= ~V9FS_ACCESS_MASK;
 316                         if (strcmp(s, "user") == 0)
 317                                 v9ses->flags |= V9FS_ACCESS_USER;
 318                         else if (strcmp(s, "any") == 0)
 319                                 v9ses->flags |= V9FS_ACCESS_ANY;
 320                         else if (strcmp(s, "client") == 0) {
 321                                 v9ses->flags |= V9FS_ACCESS_CLIENT;
 322                         } else {
 323                                 uid_t uid;
 324
 325                                 v9ses->flags |= V9FS_ACCESS_SINGLE;
 326                                 r = kstrtouint(s, 10, &uid);
 327                                 if (r) {
 328                                         ret = r;
 329                                         pr_info("Unknown access argument %s: %d\n",
 330                                                 s, r);
 331                                         kfree(s);
 332                                         continue;
 333                                 }
 334                                 v9ses->uid = make_kuid(current_user_ns(), uid);
 335                                 if (!uid_valid(v9ses->uid)) {
 336                                         ret = -EINVAL;
 337                                         pr_info("Unknown uid %s\n", s);
 338                                 }
 339                         }
 340
 341                         kfree(s);
 342                         break;
 343
 344                 case Opt_posixacl:
 345 #ifdef CONFIG_9P_FS_POSIX_ACL
 346                         v9ses->flags |= V9FS_POSIX_ACL;
 347 #else
 348                         p9_debug(P9_DEBUG_ERROR,
 349                                  "Not defined CONFIG_9P_FS_POSIX_ACL. Ignoring posixacl option\n");
 350 #endif
 351                         break;
 352
 353                 case Opt_locktimeout:
 354                         r = match_int(&args[0], &option);
 355                         if (r < 0) {
 356                                 p9_debug(P9_DEBUG_ERROR,
 357                                          "integer field, but no integer?\n");
 358                                 ret = r;
 359                                 continue;
 360                         }
 361                         if (option < 1) {
 362                                 p9_debug(P9_DEBUG_ERROR,
 363                                          "locktimeout must be a greater than zero integer.\n");
 364                                 ret = -EINVAL;
 365                                 continue;
 366                         }
 367                         v9ses->session_lock_timeout = (long)option * HZ;
 368                         break;
 369
 370                 default:
 371                         continue;
 372                 }
 373         }
 374
 375 free_and_return:
 376         kfree(tmp_options);
 377 fail_option_alloc:
 378         return ret;
 379 }
 380
 381 /**
 382  * v9fs_session_init - initialize session
 383  * @v9ses: session information structure
 384  * @dev_name: device being mounted
 385  * @data: options
 386  *
 387  */
 388
 389 struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
 390                   const char *dev_name, char *data)
 391 {
 392         struct p9_fid *fid;
 393         int rc = -ENOMEM;
 394
 395         v9ses->uname = kstrdup(V9FS_DEFUSER, GFP_KERNEL);
 396         if (!v9ses->uname)
 397                 goto err_names;
 398
 399         v9ses->aname = kstrdup(V9FS_DEFANAME, GFP_KERNEL);
 400         if (!v9ses->aname)
 401                 goto err_names;
 402         init_rwsem(&v9ses->rename_sem);
 403
 404         v9ses->uid = INVALID_UID;
 405         v9ses->dfltuid = V9FS_DEFUID;
 406         v9ses->dfltgid = V9FS_DEFGID;
 407
 408         v9ses->clnt = p9_client_create(dev_name, data);
 409         if (IS_ERR(v9ses->clnt)) {
 410                 rc = PTR_ERR(v9ses->clnt);
 411                 p9_debug(P9_DEBUG_ERROR, "problem initializing 9p client\n");
 412                 goto err_names;
 413         }
 414
 415         v9ses->flags = V9FS_ACCESS_USER;
 416
 417         if (p9_is_proto_dotl(v9ses->clnt)) {
 418                 v9ses->flags = V9FS_ACCESS_CLIENT;
 419                 v9ses->flags |= V9FS_PROTO_2000L;
 420         } else if (p9_is_proto_dotu(v9ses->clnt)) {
 421                 v9ses->flags |= V9FS_PROTO_2000U;
 422         }
 423
 424         rc = v9fs_parse_options(v9ses, data);
 425         if (rc < 0)
 426                 goto err_clnt;
 427
 428         v9ses->maxdata = v9ses->clnt->msize - P9_IOHDRSZ;
 429
 430         if (!v9fs_proto_dotl(v9ses) &&
 431             ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
 432                 /*
 433                  * We support ACCESS_CLIENT only for dotl.
 434                  * Fall back to ACCESS_USER
 435                  */
 436                 v9ses->flags &= ~V9FS_ACCESS_MASK;
 437                 v9ses->flags |= V9FS_ACCESS_USER;
 438         }
 439         /*FIXME !! */
 440         /* for legacy mode, fall back to V9FS_ACCESS_ANY */
 441         if (!(v9fs_proto_dotu(v9ses) || v9fs_proto_dotl(v9ses)) &&
 442                 ((v9ses->flags&V9FS_ACCESS_MASK) == V9FS_ACCESS_USER)) {
 443
 444                 v9ses->flags &= ~V9FS_ACCESS_MASK;
 445                 v9ses->flags |= V9FS_ACCESS_ANY;
 446                 v9ses->uid = INVALID_UID;
 447         }
 448         if (!v9fs_proto_dotl(v9ses) ||
 449                 !((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
 450                 /*
 451                  * We support ACL checks on clinet only if the protocol is
 452                  * 9P2000.L and access is V9FS_ACCESS_CLIENT.
 453                  */
 454                 v9ses->flags &= ~V9FS_ACL_MASK;
 455         }
 456
 457         fid = p9_client_attach(v9ses->clnt, NULL, v9ses->uname, INVALID_UID,
 458                                                         v9ses->aname);
 459         if (IS_ERR(fid)) {
 460                 rc = PTR_ERR(fid);
 461                 p9_debug(P9_DEBUG_ERROR, "cannot attach\n");
 462                 goto err_clnt;
 463         }
 464
 465         if ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_SINGLE)
 466                 fid->uid = v9ses->uid;
 467         else
 468                 fid->uid = INVALID_UID;
 469
 470 #ifdef CONFIG_9P_FSCACHE
 471         /* register the session for caching */
 472         if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) {
 473                 rc = v9fs_cache_session_get_cookie(v9ses, dev_name);
 474                 if (rc < 0)
 475                         goto err_clnt;
 476         }
 477 #endif
 478         spin_lock(&v9fs_sessionlist_lock);
 479         list_add(&v9ses->slist, &v9fs_sessionlist);
 480         spin_unlock(&v9fs_sessionlist_lock);
 481
 482         return fid;
 483
 484 err_clnt:
 485 #ifdef CONFIG_9P_FSCACHE
 486         kfree(v9ses->cachetag);
 487 #endif
 488         p9_client_destroy(v9ses->clnt);
 489 err_names:
 490         kfree(v9ses->uname);
 491         kfree(v9ses->aname);
 492         return ERR_PTR(rc);
 493 }
 494
 495 /**
 496  * v9fs_session_close - shutdown a session
 497  * @v9ses: session information structure
 498  *
 499  */
 500
 501 void v9fs_session_close(struct v9fs_session_info *v9ses)
 502 {
 503         if (v9ses->clnt) {
 504                 p9_client_destroy(v9ses->clnt);
 505                 v9ses->clnt = NULL;
 506         }
 507
 508 #ifdef CONFIG_9P_FSCACHE
 509         fscache_relinquish_volume(v9fs_session_cache(v9ses), NULL, false);
 510         kfree(v9ses->cachetag);
 511 #endif
 512         kfree(v9ses->uname);
 513         kfree(v9ses->aname);
 514
 515         spin_lock(&v9fs_sessionlist_lock);
 516         list_del(&v9ses->slist);
 517         spin_unlock(&v9fs_sessionlist_lock);
 518 }
 519
 520 /**
 521  * v9fs_session_cancel - terminate a session
 522  * @v9ses: session to terminate
 523  *
 524  * mark transport as disconnected and cancel all pending requests.
 525  */
 526
 527 void v9fs_session_cancel(struct v9fs_session_info *v9ses)
 528 {
 529         p9_debug(P9_DEBUG_ERROR, "cancel session %p\n", v9ses);
 530         p9_client_disconnect(v9ses->clnt);
 531 }
 532
 533 /**
 534  * v9fs_session_begin_cancel - Begin terminate of a session
 535  * @v9ses: session to terminate
 536  *
 537  * After this call we don't allow any request other than clunk.
 538  */
 539
 540 void v9fs_session_begin_cancel(struct v9fs_session_info *v9ses)
 541 {
 542         p9_debug(P9_DEBUG_ERROR, "begin cancel session %p\n", v9ses);
 543         p9_client_begin_disconnect(v9ses->clnt);
 544 }
 545
 546 extern int v9fs_error_init(void);
 547
 548 static struct kobject *v9fs_kobj;
 549
 550 #ifdef CONFIG_9P_FSCACHE
 551 /*
 552  * List caches associated with a session
 553  */
 554 static ssize_t caches_show(struct kobject *kobj,
 555                            struct kobj_attribute *attr,
 556                            char *buf)
 557 {
 558         ssize_t n = 0, count = 0, limit = PAGE_SIZE;
 559         struct v9fs_session_info *v9ses;
 560
 561         spin_lock(&v9fs_sessionlist_lock);
 562         list_for_each_entry(v9ses, &v9fs_sessionlist, slist) {
 563                 if (v9ses->cachetag) {
 564                         n = snprintf(buf, limit, "%s\n", v9ses->cachetag);
 565                         if (n < 0) {
 566                                 count = n;
 567                                 break;
 568                         }
 569
 570                         count += n;
 571                         limit -= n;
 572                 }
 573         }
 574
 575         spin_unlock(&v9fs_sessionlist_lock);
 576         return count;
 577 }
 578
 579 static struct kobj_attribute v9fs_attr_cache = __ATTR_RO(caches);
 580 #endif /* CONFIG_9P_FSCACHE */
 581
 582 static struct attribute *v9fs_attrs[] = {
 583 #ifdef CONFIG_9P_FSCACHE
 584         &v9fs_attr_cache.attr,
 585 #endif
 586         NULL,
 587 };
 588
 589 static const struct attribute_group v9fs_attr_group = {
 590         .attrs = v9fs_attrs,
 591 };
 592
 593 /**
 594  * v9fs_sysfs_init - Initialize the v9fs sysfs interface
 595  *
 596  */
 597
 598 static int __init v9fs_sysfs_init(void)
 599 {
 600         v9fs_kobj = kobject_create_and_add("9p", fs_kobj);
 601         if (!v9fs_kobj)
 602                 return -ENOMEM;
 603
 604         if (sysfs_create_group(v9fs_kobj, &v9fs_attr_group)) {
 605                 kobject_put(v9fs_kobj);
 606                 return -ENOMEM;
 607         }
 608
 609         return 0;
 610 }
 611
 612 /**
 613  * v9fs_sysfs_cleanup - Unregister the v9fs sysfs interface
 614  *
 615  */
 616
 617 static void v9fs_sysfs_cleanup(void)
 618 {
 619         sysfs_remove_group(v9fs_kobj, &v9fs_attr_group);
 620         kobject_put(v9fs_kobj);
 621 }
 622
 623 static void v9fs_inode_init_once(void *foo)
 624 {
 625         struct v9fs_inode *v9inode = (struct v9fs_inode *)foo;
 626
 627         memset(&v9inode->qid, 0, sizeof(v9inode->qid));
 628         inode_init_once(&v9inode->vfs_inode);
 629 }
 630
 631 /**
 632  * v9fs_init_inode_cache - initialize a cache for 9P
 633  * Returns 0 on success.
 634  */
 635 static int v9fs_init_inode_cache(void)
 636 {
 637         v9fs_inode_cache = kmem_cache_create("v9fs_inode_cache",
 638                                           sizeof(struct v9fs_inode),
 639                                           0, (SLAB_RECLAIM_ACCOUNT|
 640                                               SLAB_MEM_SPREAD|SLAB_ACCOUNT),
 641                                           v9fs_inode_init_once);
 642         if (!v9fs_inode_cache)
 643                 return -ENOMEM;
 644
 645         return 0;
 646 }
 647
 648 /**
 649  * v9fs_destroy_inode_cache - destroy the cache of 9P inode
 650  *
 651  */
 652 static void v9fs_destroy_inode_cache(void)
 653 {
 654         /*
 655          * Make sure all delayed rcu free inodes are flushed before we
 656          * destroy cache.
 657          */
 658         rcu_barrier();
 659         kmem_cache_destroy(v9fs_inode_cache);
 660 }
 661
 662 static int v9fs_cache_register(void)
 663 {
 664         int ret;
 665
 666         ret = v9fs_init_inode_cache();
 667         if (ret < 0)
 668                 return ret;
 669         return ret;
 670 }
 671
 672 static void v9fs_cache_unregister(void)
 673 {
 674         v9fs_destroy_inode_cache();
 675 }
 676
 677 /**
 678  * init_v9fs - Initialize module
 679  *
 680  */
 681
 682 static int __init init_v9fs(void)
 683 {
 684         int err;
 685
 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");