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         /* Lock timeout option */
  65         Opt_locktimeout,
  66         /* Error token */
  67         Opt_err
  68 };
  69
  70 static const match_table_t tokens = {
  71         {Opt_debug, "debug=%x"},
  72         {Opt_dfltuid, "dfltuid=%u"},
  73         {Opt_dfltgid, "dfltgid=%u"},
  74         {Opt_afid, "afid=%u"},
  75         {Opt_uname, "uname=%s"},
  76         {Opt_remotename, "aname=%s"},
  77         {Opt_nodevmap, "nodevmap"},
  78         {Opt_cache, "cache=%s"},
  79         {Opt_cache_loose, "loose"},
  80         {Opt_fscache, "fscache"},
  81         {Opt_mmap, "mmap"},
  82         {Opt_cachetag, "cachetag=%s"},
  83         {Opt_access, "access=%s"},
  84         {Opt_posixacl, "posixacl"},
  85         {Opt_locktimeout, "locktimeout=%u"},
  86         {Opt_err, NULL}
  87 };
  88
  89 static const char *const v9fs_cache_modes[nr__p9_cache_modes] = {
  90         [CACHE_NONE]    = "none",
  91         [CACHE_MMAP]    = "mmap",
  92         [CACHE_LOOSE]   = "loose",
  93         [CACHE_FSCACHE] = "fscache",
  94 };
  95
  96 /* Interpret mount options for cache mode */
  97 static int get_cache_mode(char *s)
  98 {
  99         int version = -EINVAL;
 100
 101         if (!strcmp(s, "loose")) {
 102                 version = CACHE_LOOSE;
 103                 p9_debug(P9_DEBUG_9P, "Cache mode: loose\n");
 104         } else if (!strcmp(s, "fscache")) {
 105                 version = CACHE_FSCACHE;
 106                 p9_debug(P9_DEBUG_9P, "Cache mode: fscache\n");
 107         } else if (!strcmp(s, "mmap")) {
 108                 version = CACHE_MMAP;
 109                 p9_debug(P9_DEBUG_9P, "Cache mode: mmap\n");
 110         } else if (!strcmp(s, "none")) {
 111                 version = CACHE_NONE;
 112                 p9_debug(P9_DEBUG_9P, "Cache mode: none\n");
 113         } else
 114                 pr_info("Unknown Cache mode %s\n", s);
 115         return version;
 116 }
 117
 118 /*
 119  * Display the mount options in /proc/mounts.
 120  */
 121 int v9fs_show_options(struct seq_file *m, struct dentry *root)
 122 {
 123         struct v9fs_session_info *v9ses = root->d_sb->s_fs_info;
 124
 125         if (v9ses->debug)
 126                 seq_printf(m, ",debug=%x", v9ses->debug);
 127         if (!uid_eq(v9ses->dfltuid, V9FS_DEFUID))
 128                 seq_printf(m, ",dfltuid=%u",
 129                            from_kuid_munged(&init_user_ns, v9ses->dfltuid));
 130         if (!gid_eq(v9ses->dfltgid, V9FS_DEFGID))
 131                 seq_printf(m, ",dfltgid=%u",
 132                            from_kgid_munged(&init_user_ns, v9ses->dfltgid));
 133         if (v9ses->afid != ~0)
 134                 seq_printf(m, ",afid=%u", v9ses->afid);
 135         if (strcmp(v9ses->uname, V9FS_DEFUSER) != 0)
 136                 seq_printf(m, ",uname=%s", v9ses->uname);
 137         if (strcmp(v9ses->aname, V9FS_DEFANAME) != 0)
 138                 seq_printf(m, ",aname=%s", v9ses->aname);
 139         if (v9ses->nodev)
 140                 seq_puts(m, ",nodevmap");
 141         if (v9ses->cache)
 142                 seq_printf(m, ",%s", v9fs_cache_modes[v9ses->cache]);
 143 #ifdef CONFIG_9P_FSCACHE
 144         if (v9ses->cachetag && v9ses->cache == CACHE_FSCACHE)
 145                 seq_printf(m, ",cachetag=%s", v9ses->cachetag);
 146 #endif
 147
 148         switch (v9ses->flags & V9FS_ACCESS_MASK) {
 149         case V9FS_ACCESS_USER:
 150                 seq_puts(m, ",access=user");
 151                 break;
 152         case V9FS_ACCESS_ANY:
 153                 seq_puts(m, ",access=any");
 154                 break;
 155         case V9FS_ACCESS_CLIENT:
 156                 seq_puts(m, ",access=client");
 157                 break;
 158         case V9FS_ACCESS_SINGLE:
 159                 seq_printf(m, ",access=%u",
 160                            from_kuid_munged(&init_user_ns, v9ses->uid));
 161                 break;
 162         }
 163
 164         if (v9ses->flags & V9FS_POSIX_ACL)
 165                 seq_puts(m, ",posixacl");
 166
 167         return p9_show_client_options(m, v9ses->clnt);
 168 }
 169
 170 /**
 171  * v9fs_parse_options - parse mount options into session structure
 172  * @v9ses: existing v9fs session information
 173  *
 174  * Return 0 upon success, -ERRNO upon failure.
 175  */
 176
 177 static int v9fs_parse_options(struct v9fs_session_info *v9ses, char *opts)
 178 {
 179         char *options, *tmp_options;
 180         substring_t args[MAX_OPT_ARGS];
 181         char *p;
 182         int option = 0;
 183         char *s, *e;
 184         int ret = 0;
 185
 186         /* setup defaults */
 187         v9ses->afid = ~0;
 188         v9ses->debug = 0;
 189         v9ses->cache = CACHE_NONE;
 190 #ifdef CONFIG_9P_FSCACHE
 191         v9ses->cachetag = NULL;
 192 #endif
 193         v9ses->session_lock_timeout = P9_LOCK_TIMEOUT;
 194
 195         if (!opts)
 196                 return 0;
 197
 198         tmp_options = kstrdup(opts, GFP_KERNEL);
 199         if (!tmp_options) {
 200                 ret = -ENOMEM;
 201                 goto fail_option_alloc;
 202         }
 203         options = tmp_options;
 204
 205         while ((p = strsep(&options, ",")) != NULL) {
 206                 int token, r;
 207                 if (!*p)
 208                         continue;
 209                 token = match_token(p, tokens, args);
 210                 switch (token) {
 211                 case Opt_debug:
 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                         } else {
 218                                 v9ses->debug = option;
 219 #ifdef CONFIG_NET_9P_DEBUG
 220                                 p9_debug_level = option;
 221 #endif
 222                         }
 223                         break;
 224
 225                 case Opt_dfltuid:
 226                         r = match_int(&args[0], &option);
 227                         if (r < 0) {
 228                                 p9_debug(P9_DEBUG_ERROR,
 229                                          "integer field, but no integer?\n");
 230                                 ret = r;
 231                                 continue;
 232                         }
 233                         v9ses->dfltuid = make_kuid(current_user_ns(), option);
 234                         if (!uid_valid(v9ses->dfltuid)) {
 235                                 p9_debug(P9_DEBUG_ERROR,
 236                                          "uid field, but not a uid?\n");
 237                                 ret = -EINVAL;
 238                         }
 239                         break;
 240                 case Opt_dfltgid:
 241                         r = match_int(&args[0], &option);
 242                         if (r < 0) {
 243                                 p9_debug(P9_DEBUG_ERROR,
 244                                          "integer field, but no integer?\n");
 245                                 ret = r;
 246                                 continue;
 247                         }
 248                         v9ses->dfltgid = make_kgid(current_user_ns(), option);
 249                         if (!gid_valid(v9ses->dfltgid)) {
 250                                 p9_debug(P9_DEBUG_ERROR,
 251                                          "gid field, but not a gid?\n");
 252                                 ret = -EINVAL;
 253                         }
 254                         break;
 255                 case Opt_afid:
 256                         r = match_int(&args[0], &option);
 257                         if (r < 0) {
 258                                 p9_debug(P9_DEBUG_ERROR,
 259                                          "integer field, but no integer?\n");
 260                                 ret = r;
 261                         } else {
 262                                 v9ses->afid = option;
 263                         }
 264                         break;
 265                 case Opt_uname:
 266                         kfree(v9ses->uname);
 267                         v9ses->uname = match_strdup(&args[0]);
 268                         if (!v9ses->uname) {
 269                                 ret = -ENOMEM;
 270                                 goto free_and_return;
 271                         }
 272                         break;
 273                 case Opt_remotename:
 274                         kfree(v9ses->aname);
 275                         v9ses->aname = match_strdup(&args[0]);
 276                         if (!v9ses->aname) {
 277                                 ret = -ENOMEM;
 278                                 goto free_and_return;
 279                         }
 280                         break;
 281                 case Opt_nodevmap:
 282                         v9ses->nodev = 1;
 283                         break;
 284                 case Opt_cache_loose:
 285                         v9ses->cache = CACHE_LOOSE;
 286                         break;
 287                 case Opt_fscache:
 288                         v9ses->cache = CACHE_FSCACHE;
 289                         break;
 290                 case Opt_mmap:
 291                         v9ses->cache = CACHE_MMAP;
 292                         break;
 293                 case Opt_cachetag:
 294 #ifdef CONFIG_9P_FSCACHE
 295                         kfree(v9ses->cachetag);
 296                         v9ses->cachetag = match_strdup(&args[0]);
 297                         if (!v9ses->cachetag) {
 298                                 ret = -ENOMEM;
 299                                 goto free_and_return;
 300                         }
 301 #endif
 302                         break;
 303                 case Opt_cache:
 304                         s = match_strdup(&args[0]);
 305                         if (!s) {
 306                                 ret = -ENOMEM;
 307                                 p9_debug(P9_DEBUG_ERROR,
 308                                          "problem allocating copy of cache arg\n");
 309                                 goto free_and_return;
 310                         }
 311                         r = get_cache_mode(s);
 312                         if (r < 0)
 313                                 ret = r;
 314                         else
 315                                 v9ses->cache = r;
 316
 317                         kfree(s);
 318                         break;
 319
 320                 case Opt_access:
 321                         s = match_strdup(&args[0]);
 322                         if (!s) {
 323                                 ret = -ENOMEM;
 324                                 p9_debug(P9_DEBUG_ERROR,
 325                                          "problem allocating copy of access arg\n");
 326                                 goto free_and_return;
 327                         }
 328
 329                         v9ses->flags &= ~V9FS_ACCESS_MASK;
 330                         if (strcmp(s, "user") == 0)
 331                                 v9ses->flags |= V9FS_ACCESS_USER;
 332                         else if (strcmp(s, "any") == 0)
 333                                 v9ses->flags |= V9FS_ACCESS_ANY;
 334                         else if (strcmp(s, "client") == 0) {
 335                                 v9ses->flags |= V9FS_ACCESS_CLIENT;
 336                         } else {
 337                                 uid_t uid;
 338                                 v9ses->flags |= V9FS_ACCESS_SINGLE;
 339                                 uid = simple_strtoul(s, &e, 10);
 340                                 if (*e != '\0') {
 341                                         ret = -EINVAL;
 342                                         pr_info("Unknown access argument %s\n",
 343                                                 s);
 344                                         kfree(s);
 345                                         continue;
 346                                 }
 347                                 v9ses->uid = make_kuid(current_user_ns(), uid);
 348                                 if (!uid_valid(v9ses->uid)) {
 349                                         ret = -EINVAL;
 350                                         pr_info("Unknown uid %s\n", s);
 351                                 }
 352                         }
 353
 354                         kfree(s);
 355                         break;
 356
 357                 case Opt_posixacl:
 358 #ifdef CONFIG_9P_FS_POSIX_ACL
 359                         v9ses->flags |= V9FS_POSIX_ACL;
 360 #else
 361                         p9_debug(P9_DEBUG_ERROR,
 362                                  "Not defined CONFIG_9P_FS_POSIX_ACL. Ignoring posixacl option\n");
 363 #endif
 364                         break;
 365
 366                 case Opt_locktimeout:
 367                         r = match_int(&args[0], &option);
 368                         if (r < 0) {
 369                                 p9_debug(P9_DEBUG_ERROR,
 370                                          "integer field, but no integer?\n");
 371                                 ret = r;
 372                                 continue;
 373                         }
 374                         if (option < 1) {
 375                                 p9_debug(P9_DEBUG_ERROR,
 376                                          "locktimeout must be a greater than zero integer.\n");
 377                                 ret = -EINVAL;
 378                                 continue;
 379                         }
 380                         v9ses->session_lock_timeout = (long)option * HZ;
 381                         break;
 382
 383                 default:
 384                         continue;
 385                 }
 386         }
 387
 388 free_and_return:
 389         kfree(tmp_options);
 390 fail_option_alloc:
 391         return ret;
 392 }
 393
 394 /**
 395  * v9fs_session_init - initialize session
 396  * @v9ses: session information structure
 397  * @dev_name: device being mounted
 398  * @data: options
 399  *
 400  */
 401
 402 struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
 403                   const char *dev_name, char *data)
 404 {
 405         struct p9_fid *fid;
 406         int rc = -ENOMEM;
 407
 408         v9ses->uname = kstrdup(V9FS_DEFUSER, GFP_KERNEL);
 409         if (!v9ses->uname)
 410                 goto err_names;
 411
 412         v9ses->aname = kstrdup(V9FS_DEFANAME, GFP_KERNEL);
 413         if (!v9ses->aname)
 414                 goto err_names;
 415         init_rwsem(&v9ses->rename_sem);
 416
 417         v9ses->uid = INVALID_UID;
 418         v9ses->dfltuid = V9FS_DEFUID;
 419         v9ses->dfltgid = V9FS_DEFGID;
 420
 421         v9ses->clnt = p9_client_create(dev_name, data);
 422         if (IS_ERR(v9ses->clnt)) {
 423                 rc = PTR_ERR(v9ses->clnt);
 424                 p9_debug(P9_DEBUG_ERROR, "problem initializing 9p client\n");
 425                 goto err_names;
 426         }
 427
 428         v9ses->flags = V9FS_ACCESS_USER;
 429
 430         if (p9_is_proto_dotl(v9ses->clnt)) {
 431                 v9ses->flags = V9FS_ACCESS_CLIENT;
 432                 v9ses->flags |= V9FS_PROTO_2000L;
 433         } else if (p9_is_proto_dotu(v9ses->clnt)) {
 434                 v9ses->flags |= V9FS_PROTO_2000U;
 435         }
 436
 437         rc = v9fs_parse_options(v9ses, data);
 438         if (rc < 0)
 439                 goto err_clnt;
 440
 441         v9ses->maxdata = v9ses->clnt->msize - P9_IOHDRSZ;
 442
 443         if (!v9fs_proto_dotl(v9ses) &&
 444             ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
 445                 /*
 446                  * We support ACCESS_CLIENT only for dotl.
 447                  * Fall back to ACCESS_USER
 448                  */
 449                 v9ses->flags &= ~V9FS_ACCESS_MASK;
 450                 v9ses->flags |= V9FS_ACCESS_USER;
 451         }
 452         /*FIXME !! */
 453         /* for legacy mode, fall back to V9FS_ACCESS_ANY */
 454         if (!(v9fs_proto_dotu(v9ses) || v9fs_proto_dotl(v9ses)) &&
 455                 ((v9ses->flags&V9FS_ACCESS_MASK) == V9FS_ACCESS_USER)) {
 456
 457                 v9ses->flags &= ~V9FS_ACCESS_MASK;
 458                 v9ses->flags |= V9FS_ACCESS_ANY;
 459                 v9ses->uid = INVALID_UID;
 460         }
 461         if (!v9fs_proto_dotl(v9ses) ||
 462                 !((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
 463                 /*
 464                  * We support ACL checks on clinet only if the protocol is
 465                  * 9P2000.L and access is V9FS_ACCESS_CLIENT.
 466                  */
 467                 v9ses->flags &= ~V9FS_ACL_MASK;
 468         }
 469
 470         fid = p9_client_attach(v9ses->clnt, NULL, v9ses->uname, INVALID_UID,
 471                                                         v9ses->aname);
 472         if (IS_ERR(fid)) {
 473                 rc = PTR_ERR(fid);
 474                 p9_debug(P9_DEBUG_ERROR, "cannot attach\n");
 475                 goto err_clnt;
 476         }
 477
 478         if ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_SINGLE)
 479                 fid->uid = v9ses->uid;
 480         else
 481                 fid->uid = INVALID_UID;
 482
 483 #ifdef CONFIG_9P_FSCACHE
 484         /* register the session for caching */
 485         v9fs_cache_session_get_cookie(v9ses);
 486 #endif
 487         spin_lock(&v9fs_sessionlist_lock);
 488         list_add(&v9ses->slist, &v9fs_sessionlist);
 489         spin_unlock(&v9fs_sessionlist_lock);
 490
 491         return fid;
 492
 493 err_clnt:
 494 #ifdef CONFIG_9P_FSCACHE
 495         kfree(v9ses->cachetag);
 496 #endif
 497         p9_client_destroy(v9ses->clnt);
 498 err_names:
 499         kfree(v9ses->uname);
 500         kfree(v9ses->aname);
 501         return ERR_PTR(rc);
 502 }
 503
 504 /**
 505  * v9fs_session_close - shutdown a session
 506  * @v9ses: session information structure
 507  *
 508  */
 509
 510 void v9fs_session_close(struct v9fs_session_info *v9ses)
 511 {
 512         if (v9ses->clnt) {
 513                 p9_client_destroy(v9ses->clnt);
 514                 v9ses->clnt = NULL;
 515         }
 516
 517 #ifdef CONFIG_9P_FSCACHE
 518         if (v9ses->fscache) {
 519                 v9fs_cache_session_put_cookie(v9ses);
 520                 kfree(v9ses->cachetag);
 521         }
 522 #endif
 523         kfree(v9ses->uname);
 524         kfree(v9ses->aname);
 525
 526         spin_lock(&v9fs_sessionlist_lock);
 527         list_del(&v9ses->slist);
 528         spin_unlock(&v9fs_sessionlist_lock);
 529 }
 530
 531 /**
 532  * v9fs_session_cancel - terminate a session
 533  * @v9ses: session to terminate
 534  *
 535  * mark transport as disconnected and cancel all pending requests.
 536  */
 537
 538 void v9fs_session_cancel(struct v9fs_session_info *v9ses) {
 539         p9_debug(P9_DEBUG_ERROR, "cancel session %p\n", v9ses);
 540         p9_client_disconnect(v9ses->clnt);
 541 }
 542
 543 /**
 544  * v9fs_session_begin_cancel - Begin terminate of a session
 545  * @v9ses: session to terminate
 546  *
 547  * After this call we don't allow any request other than clunk.
 548  */
 549
 550 void v9fs_session_begin_cancel(struct v9fs_session_info *v9ses)
 551 {
 552         p9_debug(P9_DEBUG_ERROR, "begin cancel session %p\n", v9ses);
 553         p9_client_begin_disconnect(v9ses->clnt);
 554 }
 555
 556 extern int v9fs_error_init(void);
 557
 558 static struct kobject *v9fs_kobj;
 559
 560 #ifdef CONFIG_9P_FSCACHE
 561 /**
 562  * caches_show - list caches associated with a session
 563  *
 564  * Returns the size of buffer written.
 565  */
 566
 567 static ssize_t caches_show(struct kobject *kobj,
 568                            struct kobj_attribute *attr,
 569                            char *buf)
 570 {
 571         ssize_t n = 0, count = 0, limit = PAGE_SIZE;
 572         struct v9fs_session_info *v9ses;
 573
 574         spin_lock(&v9fs_sessionlist_lock);
 575         list_for_each_entry(v9ses, &v9fs_sessionlist, slist) {
 576                 if (v9ses->cachetag) {
 577                         n = snprintf(buf, limit, "%s\n", v9ses->cachetag);
 578                         if (n < 0) {
 579                                 count = n;
 580                                 break;
 581                         }
 582
 583                         count += n;
 584                         limit -= n;
 585                 }
 586         }
 587
 588         spin_unlock(&v9fs_sessionlist_lock);
 589         return count;
 590 }
 591
 592 static struct kobj_attribute v9fs_attr_cache = __ATTR_RO(caches);
 593 #endif /* CONFIG_9P_FSCACHE */
 594
 595 static struct attribute *v9fs_attrs[] = {
 596 #ifdef CONFIG_9P_FSCACHE
 597         &v9fs_attr_cache.attr,
 598 #endif
 599         NULL,
 600 };
 601
 602 static struct attribute_group v9fs_attr_group = {
 603         .attrs = v9fs_attrs,
 604 };
 605
 606 /**
 607  * v9fs_sysfs_init - Initialize the v9fs sysfs interface
 608  *
 609  */
 610
 611 static int __init v9fs_sysfs_init(void)
 612 {
 613         v9fs_kobj = kobject_create_and_add("9p", fs_kobj);
 614         if (!v9fs_kobj)
 615                 return -ENOMEM;
 616
 617         if (sysfs_create_group(v9fs_kobj, &v9fs_attr_group)) {
 618                 kobject_put(v9fs_kobj);
 619                 return -ENOMEM;
 620         }
 621
 622         return 0;
 623 }
 624
 625 /**
 626  * v9fs_sysfs_cleanup - Unregister the v9fs sysfs interface
 627  *
 628  */
 629
 630 static void v9fs_sysfs_cleanup(void)
 631 {
 632         sysfs_remove_group(v9fs_kobj, &v9fs_attr_group);
 633         kobject_put(v9fs_kobj);
 634 }
 635
 636 static void v9fs_inode_init_once(void *foo)
 637 {
 638         struct v9fs_inode *v9inode = (struct v9fs_inode *)foo;
 639 #ifdef CONFIG_9P_FSCACHE
 640         v9inode->fscache = NULL;
 641 #endif
 642         memset(&v9inode->qid, 0, sizeof(v9inode->qid));
 643         inode_init_once(&v9inode->vfs_inode);
 644 }
 645
 646 /**
 647  * v9fs_init_inode_cache - initialize a cache for 9P
 648  * Returns 0 on success.
 649  */
 650 static int v9fs_init_inode_cache(void)
 651 {
 652         v9fs_inode_cache = kmem_cache_create("v9fs_inode_cache",
 653                                           sizeof(struct v9fs_inode),
 654                                           0, (SLAB_RECLAIM_ACCOUNT|
 655                                               SLAB_MEM_SPREAD|SLAB_ACCOUNT),
 656                                           v9fs_inode_init_once);
 657         if (!v9fs_inode_cache)
 658                 return -ENOMEM;
 659
 660         return 0;
 661 }
 662
 663 /**
 664  * v9fs_destroy_inode_cache - destroy the cache of 9P inode
 665  *
 666  */
 667 static void v9fs_destroy_inode_cache(void)
 668 {
 669         /*
 670          * Make sure all delayed rcu free inodes are flushed before we
 671          * destroy cache.
 672          */
 673         rcu_barrier();
 674         kmem_cache_destroy(v9fs_inode_cache);
 675 }
 676
 677 static int v9fs_cache_register(void)
 678 {
 679         int ret;
 680         ret = v9fs_init_inode_cache();
 681         if (ret < 0)
 682                 return ret;
 683 #ifdef CONFIG_9P_FSCACHE
 684         ret = fscache_register_netfs(&v9fs_cache_netfs);
 685         if (ret < 0)
 686                 v9fs_destroy_inode_cache();
 687 #endif
 688         return ret;
 689 }
 690
 691 static void v9fs_cache_unregister(void)
 692 {
 693         v9fs_destroy_inode_cache();
 694 #ifdef CONFIG_9P_FSCACHE
 695         fscache_unregister_netfs(&v9fs_cache_netfs);
 696 #endif
 697 }
 698
 699 /**
 700  * init_v9fs - Initialize module
 701  *
 702  */
 703
 704 static int __init init_v9fs(void)
 705 {
 706         int err;
 707         pr_info("Installing v9fs 9p2000 file system support\n");
 708         /* TODO: Setup list of registered trasnport modules */
 709
 710         err = v9fs_cache_register();
 711         if (err < 0) {
 712                 pr_err("Failed to register v9fs for caching\n");
 713                 return err;
 714         }
 715
 716         err = v9fs_sysfs_init();
 717         if (err < 0) {
 718                 pr_err("Failed to register with sysfs\n");
 719                 goto out_cache;
 720         }
 721         err = register_filesystem(&v9fs_fs_type);
 722         if (err < 0) {
 723                 pr_err("Failed to register filesystem\n");
 724                 goto out_sysfs_cleanup;
 725         }
 726
 727         return 0;
 728
 729 out_sysfs_cleanup:
 730         v9fs_sysfs_cleanup();
 731
 732 out_cache:
 733         v9fs_cache_unregister();
 734
 735         return err;
 736 }
 737
 738 /**
 739  * exit_v9fs - shutdown module
 740  *
 741  */
 742
 743 static void __exit exit_v9fs(void)
 744 {
 745         v9fs_sysfs_cleanup();
 746         v9fs_cache_unregister();
 747         unregister_filesystem(&v9fs_fs_type);
 748 }
 749
 750 module_init(init_v9fs)
 751 module_exit(exit_v9fs)
 752
 753 MODULE_AUTHOR("Latchesar Ionkov <lucho@ionkov.net>");
 754 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
 755 MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
 756 MODULE_LICENSE("GPL");