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