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 <[email protected]>
   7  *  Copyright (C) 2002 by Ron Minnich <[email protected]>
   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 = option;
 165                         break;
 166                 case Opt_dfltgid:
 167                         r = match_int(&args[0], &option);
 168                         if (r < 0) {
 169                                 p9_debug(P9_DEBUG_ERROR,
 170                                          "integer field, but no integer?\n");
 171                                 ret = r;
 172                                 continue;
 173                         }
 174                         v9ses->dfltgid = option;
 175                         break;
 176                 case Opt_afid:
 177                         r = match_int(&args[0], &option);
 178                         if (r < 0) {
 179                                 p9_debug(P9_DEBUG_ERROR,
 180                                          "integer field, but no integer?\n");
 181                                 ret = r;
 182                                 continue;
 183                         }
 184                         v9ses->afid = option;
 185                         break;
 186                 case Opt_uname:
 187                         kfree(v9ses->uname);
 188                         v9ses->uname = match_strdup(&args[0]);
 189                         if (!v9ses->uname) {
 190                                 ret = -ENOMEM;
 191                                 goto free_and_return;
 192                         }
 193                         break;
 194                 case Opt_remotename:
 195                         kfree(v9ses->aname);
 196                         v9ses->aname = match_strdup(&args[0]);
 197                         if (!v9ses->aname) {
 198                                 ret = -ENOMEM;
 199                                 goto free_and_return;
 200                         }
 201                         break;
 202                 case Opt_nodevmap:
 203                         v9ses->nodev = 1;
 204                         break;
 205                 case Opt_cache_loose:
 206                         v9ses->cache = CACHE_LOOSE;
 207                         break;
 208                 case Opt_fscache:
 209                         v9ses->cache = CACHE_FSCACHE;
 210                         break;
 211                 case Opt_cachetag:
 212 #ifdef CONFIG_9P_FSCACHE
 213                         v9ses->cachetag = match_strdup(&args[0]);
 214 #endif
 215                         break;
 216                 case Opt_cache:
 217                         s = match_strdup(&args[0]);
 218                         if (!s) {
 219                                 ret = -ENOMEM;
 220                                 p9_debug(P9_DEBUG_ERROR,
 221                                          "problem allocating copy of cache arg\n");
 222                                 goto free_and_return;
 223                         }
 224                         ret = get_cache_mode(s);
 225                         if (ret == -EINVAL) {
 226                                 kfree(s);
 227                                 goto free_and_return;
 228                         }
 229
 230                         v9ses->cache = ret;
 231                         kfree(s);
 232                         break;
 233
 234                 case Opt_access:
 235                         s = match_strdup(&args[0]);
 236                         if (!s) {
 237                                 ret = -ENOMEM;
 238                                 p9_debug(P9_DEBUG_ERROR,
 239                                          "problem allocating copy of access arg\n");
 240                                 goto free_and_return;
 241                         }
 242
 243                         v9ses->flags &= ~V9FS_ACCESS_MASK;
 244                         if (strcmp(s, "user") == 0)
 245                                 v9ses->flags |= V9FS_ACCESS_USER;
 246                         else if (strcmp(s, "any") == 0)
 247                                 v9ses->flags |= V9FS_ACCESS_ANY;
 248                         else if (strcmp(s, "client") == 0) {
 249                                 v9ses->flags |= V9FS_ACCESS_CLIENT;
 250                         } else {
 251                                 v9ses->flags |= V9FS_ACCESS_SINGLE;
 252                                 v9ses->uid = simple_strtoul(s, &e, 10);
 253                                 if (*e != '\0') {
 254                                         ret = -EINVAL;
 255                                         pr_info("Unknown access argument %s\n",
 256                                                 s);
 257                                         kfree(s);
 258                                         goto free_and_return;
 259                                 }
 260                         }
 261
 262                         kfree(s);
 263                         break;
 264
 265                 case Opt_posixacl:
 266 #ifdef CONFIG_9P_FS_POSIX_ACL
 267                         v9ses->flags |= V9FS_POSIX_ACL;
 268 #else
 269                         p9_debug(P9_DEBUG_ERROR,
 270                                  "Not defined CONFIG_9P_FS_POSIX_ACL. Ignoring posixacl option\n");
 271 #endif
 272                         break;
 273
 274                 default:
 275                         continue;
 276                 }
 277         }
 278
 279 free_and_return:
 280         kfree(tmp_options);
 281 fail_option_alloc:
 282         return ret;
 283 }
 284
 285 /**
 286  * v9fs_session_init - initialize session
 287  * @v9ses: session information structure
 288  * @dev_name: device being mounted
 289  * @data: options
 290  *
 291  */
 292
 293 struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
 294                   const char *dev_name, char *data)
 295 {
 296         int retval = -EINVAL;
 297         struct p9_fid *fid;
 298         int rc;
 299
 300         v9ses->uname = kstrdup(V9FS_DEFUSER, GFP_KERNEL);
 301         if (!v9ses->uname)
 302                 return ERR_PTR(-ENOMEM);
 303
 304         v9ses->aname = kstrdup(V9FS_DEFANAME, GFP_KERNEL);
 305         if (!v9ses->aname) {
 306                 kfree(v9ses->uname);
 307                 return ERR_PTR(-ENOMEM);
 308         }
 309         init_rwsem(&v9ses->rename_sem);
 310
 311         rc = bdi_setup_and_register(&v9ses->bdi, "9p", BDI_CAP_MAP_COPY);
 312         if (rc) {
 313                 kfree(v9ses->aname);
 314                 kfree(v9ses->uname);
 315                 return ERR_PTR(rc);
 316         }
 317
 318         spin_lock(&v9fs_sessionlist_lock);
 319         list_add(&v9ses->slist, &v9fs_sessionlist);
 320         spin_unlock(&v9fs_sessionlist_lock);
 321
 322         v9ses->uid = ~0;
 323         v9ses->dfltuid = V9FS_DEFUID;
 324         v9ses->dfltgid = V9FS_DEFGID;
 325
 326         v9ses->clnt = p9_client_create(dev_name, data);
 327         if (IS_ERR(v9ses->clnt)) {
 328                 retval = PTR_ERR(v9ses->clnt);
 329                 v9ses->clnt = NULL;
 330                 p9_debug(P9_DEBUG_ERROR, "problem initializing 9p client\n");
 331                 goto error;
 332         }
 333
 334         v9ses->flags = V9FS_ACCESS_USER;
 335
 336         if (p9_is_proto_dotl(v9ses->clnt)) {
 337                 v9ses->flags = V9FS_ACCESS_CLIENT;
 338                 v9ses->flags |= V9FS_PROTO_2000L;
 339         } else if (p9_is_proto_dotu(v9ses->clnt)) {
 340                 v9ses->flags |= V9FS_PROTO_2000U;
 341         }
 342
 343         rc = v9fs_parse_options(v9ses, data);
 344         if (rc < 0) {
 345                 retval = rc;
 346                 goto error;
 347         }
 348
 349         v9ses->maxdata = v9ses->clnt->msize - P9_IOHDRSZ;
 350
 351         if (!v9fs_proto_dotl(v9ses) &&
 352             ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
 353                 /*
 354                  * We support ACCESS_CLIENT only for dotl.
 355                  * Fall back to ACCESS_USER
 356                  */
 357                 v9ses->flags &= ~V9FS_ACCESS_MASK;
 358                 v9ses->flags |= V9FS_ACCESS_USER;
 359         }
 360         /*FIXME !! */
 361         /* for legacy mode, fall back to V9FS_ACCESS_ANY */
 362         if (!(v9fs_proto_dotu(v9ses) || v9fs_proto_dotl(v9ses)) &&
 363                 ((v9ses->flags&V9FS_ACCESS_MASK) == V9FS_ACCESS_USER)) {
 364
 365                 v9ses->flags &= ~V9FS_ACCESS_MASK;
 366                 v9ses->flags |= V9FS_ACCESS_ANY;
 367                 v9ses->uid = ~0;
 368         }
 369         if (!v9fs_proto_dotl(v9ses) ||
 370                 !((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
 371                 /*
 372                  * We support ACL checks on clinet only if the protocol is
 373                  * 9P2000.L and access is V9FS_ACCESS_CLIENT.
 374                  */
 375                 v9ses->flags &= ~V9FS_ACL_MASK;
 376         }
 377
 378         fid = p9_client_attach(v9ses->clnt, NULL, v9ses->uname, ~0,
 379                                                         v9ses->aname);
 380         if (IS_ERR(fid)) {
 381                 retval = PTR_ERR(fid);
 382                 fid = NULL;
 383                 p9_debug(P9_DEBUG_ERROR, "cannot attach\n");
 384                 goto error;
 385         }
 386
 387         if ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_SINGLE)
 388                 fid->uid = v9ses->uid;
 389         else
 390                 fid->uid = ~0;
 391
 392 #ifdef CONFIG_9P_FSCACHE
 393         /* register the session for caching */
 394         v9fs_cache_session_get_cookie(v9ses);
 395 #endif
 396
 397         return fid;
 398
 399 error:
 400         bdi_destroy(&v9ses->bdi);
 401         return ERR_PTR(retval);
 402 }
 403
 404 /**
 405  * v9fs_session_close - shutdown a session
 406  * @v9ses: session information structure
 407  *
 408  */
 409
 410 void v9fs_session_close(struct v9fs_session_info *v9ses)
 411 {
 412         if (v9ses->clnt) {
 413                 p9_client_destroy(v9ses->clnt);
 414                 v9ses->clnt = NULL;
 415         }
 416
 417 #ifdef CONFIG_9P_FSCACHE
 418         if (v9ses->fscache) {
 419                 v9fs_cache_session_put_cookie(v9ses);
 420                 kfree(v9ses->cachetag);
 421         }
 422 #endif
 423         kfree(v9ses->uname);
 424         kfree(v9ses->aname);
 425
 426         bdi_destroy(&v9ses->bdi);
 427
 428         spin_lock(&v9fs_sessionlist_lock);
 429         list_del(&v9ses->slist);
 430         spin_unlock(&v9fs_sessionlist_lock);
 431 }
 432
 433 /**
 434  * v9fs_session_cancel - terminate a session
 435  * @v9ses: session to terminate
 436  *
 437  * mark transport as disconnected and cancel all pending requests.
 438  */
 439
 440 void v9fs_session_cancel(struct v9fs_session_info *v9ses) {
 441         p9_debug(P9_DEBUG_ERROR, "cancel session %p\n", v9ses);
 442         p9_client_disconnect(v9ses->clnt);
 443 }
 444
 445 /**
 446  * v9fs_session_begin_cancel - Begin terminate of a session
 447  * @v9ses: session to terminate
 448  *
 449  * After this call we don't allow any request other than clunk.
 450  */
 451
 452 void v9fs_session_begin_cancel(struct v9fs_session_info *v9ses)
 453 {
 454         p9_debug(P9_DEBUG_ERROR, "begin cancel session %p\n", v9ses);
 455         p9_client_begin_disconnect(v9ses->clnt);
 456 }
 457
 458 extern int v9fs_error_init(void);
 459
 460 static struct kobject *v9fs_kobj;
 461
 462 #ifdef CONFIG_9P_FSCACHE
 463 /**
 464  * caches_show - list caches associated with a session
 465  *
 466  * Returns the size of buffer written.
 467  */
 468
 469 static ssize_t caches_show(struct kobject *kobj,
 470                            struct kobj_attribute *attr,
 471                            char *buf)
 472 {
 473         ssize_t n = 0, count = 0, limit = PAGE_SIZE;
 474         struct v9fs_session_info *v9ses;
 475
 476         spin_lock(&v9fs_sessionlist_lock);
 477         list_for_each_entry(v9ses, &v9fs_sessionlist, slist) {
 478                 if (v9ses->cachetag) {
 479                         n = snprintf(buf, limit, "%s\n", v9ses->cachetag);
 480                         if (n < 0) {
 481                                 count = n;
 482                                 break;
 483                         }
 484
 485                         count += n;
 486                         limit -= n;
 487                 }
 488         }
 489
 490         spin_unlock(&v9fs_sessionlist_lock);
 491         return count;
 492 }
 493
 494 static struct kobj_attribute v9fs_attr_cache = __ATTR_RO(caches);
 495 #endif /* CONFIG_9P_FSCACHE */
 496
 497 static struct attribute *v9fs_attrs[] = {
 498 #ifdef CONFIG_9P_FSCACHE
 499         &v9fs_attr_cache.attr,
 500 #endif
 501         NULL,
 502 };
 503
 504 static struct attribute_group v9fs_attr_group = {
 505         .attrs = v9fs_attrs,
 506 };
 507
 508 /**
 509  * v9fs_sysfs_init - Initialize the v9fs sysfs interface
 510  *
 511  */
 512
 513 static int v9fs_sysfs_init(void)
 514 {
 515         v9fs_kobj = kobject_create_and_add("9p", fs_kobj);
 516         if (!v9fs_kobj)
 517                 return -ENOMEM;
 518
 519         if (sysfs_create_group(v9fs_kobj, &v9fs_attr_group)) {
 520                 kobject_put(v9fs_kobj);
 521                 return -ENOMEM;
 522         }
 523
 524         return 0;
 525 }
 526
 527 /**
 528  * v9fs_sysfs_cleanup - Unregister the v9fs sysfs interface
 529  *
 530  */
 531
 532 static void v9fs_sysfs_cleanup(void)
 533 {
 534         sysfs_remove_group(v9fs_kobj, &v9fs_attr_group);
 535         kobject_put(v9fs_kobj);
 536 }
 537
 538 static void v9fs_inode_init_once(void *foo)
 539 {
 540         struct v9fs_inode *v9inode = (struct v9fs_inode *)foo;
 541 #ifdef CONFIG_9P_FSCACHE
 542         v9inode->fscache = NULL;
 543 #endif
 544         memset(&v9inode->qid, 0, sizeof(v9inode->qid));
 545         inode_init_once(&v9inode->vfs_inode);
 546 }
 547
 548 /**
 549  * v9fs_init_inode_cache - initialize a cache for 9P
 550  * Returns 0 on success.
 551  */
 552 static int v9fs_init_inode_cache(void)
 553 {
 554         v9fs_inode_cache = kmem_cache_create("v9fs_inode_cache",
 555                                           sizeof(struct v9fs_inode),
 556                                           0, (SLAB_RECLAIM_ACCOUNT|
 557                                               SLAB_MEM_SPREAD),
 558                                           v9fs_inode_init_once);
 559         if (!v9fs_inode_cache)
 560                 return -ENOMEM;
 561
 562         return 0;
 563 }
 564
 565 /**
 566  * v9fs_destroy_inode_cache - destroy the cache of 9P inode
 567  *
 568  */
 569 static void v9fs_destroy_inode_cache(void)
 570 {
 571         /*
 572          * Make sure all delayed rcu free inodes are flushed before we
 573          * destroy cache.
 574          */
 575         rcu_barrier();
 576         kmem_cache_destroy(v9fs_inode_cache);
 577 }
 578
 579 static int v9fs_cache_register(void)
 580 {
 581         int ret;
 582         ret = v9fs_init_inode_cache();
 583         if (ret < 0)
 584                 return ret;
 585 #ifdef CONFIG_9P_FSCACHE
 586         return fscache_register_netfs(&v9fs_cache_netfs);
 587 #else
 588         return ret;
 589 #endif
 590 }
 591
 592 static void v9fs_cache_unregister(void)
 593 {
 594         v9fs_destroy_inode_cache();
 595 #ifdef CONFIG_9P_FSCACHE
 596         fscache_unregister_netfs(&v9fs_cache_netfs);
 597 #endif
 598 }
 599
 600 /**
 601  * init_v9fs - Initialize module
 602  *
 603  */
 604
 605 static int __init init_v9fs(void)
 606 {
 607         int err;
 608         pr_info("Installing v9fs 9p2000 file system support\n");
 609         /* TODO: Setup list of registered trasnport modules */
 610
 611         err = v9fs_cache_register();
 612         if (err < 0) {
 613                 pr_err("Failed to register v9fs for caching\n");
 614                 return err;
 615         }
 616
 617         err = v9fs_sysfs_init();
 618         if (err < 0) {
 619                 pr_err("Failed to register with sysfs\n");
 620                 goto out_cache;
 621         }
 622         err = register_filesystem(&v9fs_fs_type);
 623         if (err < 0) {
 624                 pr_err("Failed to register filesystem\n");
 625                 goto out_sysfs_cleanup;
 626         }
 627
 628         return 0;
 629
 630 out_sysfs_cleanup:
 631         v9fs_sysfs_cleanup();
 632
 633 out_cache:
 634         v9fs_cache_unregister();
 635
 636         return err;
 637 }
 638
 639 /**
 640  * exit_v9fs - shutdown module
 641  *
 642  */
 643
 644 static void __exit exit_v9fs(void)
 645 {
 646         v9fs_sysfs_cleanup();
 647         v9fs_cache_unregister();
 648         unregister_filesystem(&v9fs_fs_type);
 649 }
 650
 651 module_init(init_v9fs)
 652 module_exit(exit_v9fs)
 653
 654 MODULE_AUTHOR("Latchesar Ionkov <[email protected]>");
 655 MODULE_AUTHOR("Eric Van Hensbergen <[email protected]>");
 656 MODULE_AUTHOR("Ron Minnich <[email protected]>");
 657 MODULE_LICENSE("GPL");