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