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