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 #include <linux/module.h>
  27 #include <linux/errno.h>
  28 #include <linux/fs.h>
  29 #include <linux/sched.h>
  30 #include <linux/parser.h>
  31 #include <linux/idr.h>
  32 #include <linux/slab.h>
  33 #include <net/9p/9p.h>
  34 #include <net/9p/client.h>
  35 #include <net/9p/transport.h>
  36 #include "v9fs.h"
  37 #include "v9fs_vfs.h"
  38 #include "cache.h"
  39
  40 static DEFINE_SPINLOCK(v9fs_sessionlist_lock);
  41 static LIST_HEAD(v9fs_sessionlist);
  42 struct kmem_cache *v9fs_inode_cache;
  43
  44 /*
  45  * Option Parsing (code inspired by NFS code)
  46  *  NOTE: each transport will parse its own options
  47  */
  48
  49 enum {
  50         /* Options that take integer arguments */
  51         Opt_debug, Opt_dfltuid, Opt_dfltgid, Opt_afid,
  52         /* String options */
  53         Opt_uname, Opt_remotename, Opt_trans, Opt_cache, Opt_cachetag,
  54         /* Options that take no arguments */
  55         Opt_nodevmap,
  56         /* Cache options */
  57         Opt_cache_loose, Opt_fscache,
  58         /* Access options */
  59         Opt_access, Opt_posixacl,
  60         /* Error token */
  61         Opt_err
  62 };
  63
  64 static const match_table_t tokens = {
  65         {Opt_debug, "debug=%x"},
  66         {Opt_dfltuid, "dfltuid=%u"},
  67         {Opt_dfltgid, "dfltgid=%u"},
  68         {Opt_afid, "afid=%u"},
  69         {Opt_uname, "uname=%s"},
  70         {Opt_remotename, "aname=%s"},
  71         {Opt_nodevmap, "nodevmap"},
  72         {Opt_cache, "cache=%s"},
  73         {Opt_cache_loose, "loose"},
  74         {Opt_fscache, "fscache"},
  75         {Opt_cachetag, "cachetag=%s"},
  76         {Opt_access, "access=%s"},
  77         {Opt_posixacl, "posixacl"},
  78         {Opt_err, NULL}
  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_DPRINTK(P9_DEBUG_9P, "Cache mode: loose\n");
  89         } else if (!strcmp(s, "fscache")) {
  90                 version = CACHE_FSCACHE;
  91                 P9_DPRINTK(P9_DEBUG_9P, "Cache mode: fscache\n");
  92         } else if (!strcmp(s, "none")) {
  93                 version = CACHE_NONE;
  94                 P9_DPRINTK(P9_DEBUG_9P, "Cache mode: none\n");
  95         } else
  96                 printk(KERN_INFO "9p: Unknown Cache mode %s.\n", s);
  97         return version;
  98 }
  99
 100 /**
 101  * v9fs_parse_options - parse mount options into session structure
 102  * @v9ses: existing v9fs session information
 103  *
 104  * Return 0 upon success, -ERRNO upon failure.
 105  */
 106
 107 static int v9fs_parse_options(struct v9fs_session_info *v9ses, char *opts)
 108 {
 109         char *options, *tmp_options;
 110         substring_t args[MAX_OPT_ARGS];
 111         char *p;
 112         int option = 0;
 113         char *s, *e;
 114         int ret = 0;
 115
 116         /* setup defaults */
 117         v9ses->afid = ~0;
 118         v9ses->debug = 0;
 119         v9ses->cache = CACHE_NONE;
 120 #ifdef CONFIG_9P_FSCACHE
 121         v9ses->cachetag = NULL;
 122 #endif
 123
 124         if (!opts)
 125                 return 0;
 126
 127         tmp_options = kstrdup(opts, GFP_KERNEL);
 128         if (!tmp_options) {
 129                 ret = -ENOMEM;
 130                 goto fail_option_alloc;
 131         }
 132         options = tmp_options;
 133
 134         while ((p = strsep(&options, ",")) != NULL) {
 135                 int token, r;
 136                 if (!*p)
 137                         continue;
 138                 token = match_token(p, tokens, args);
 139                 switch (token) {
 140                 case Opt_debug:
 141                         r = match_int(&args[0], &option);
 142                         if (r < 0) {
 143                                 P9_DPRINTK(P9_DEBUG_ERROR,
 144                                            "integer field, but no integer?\n");
 145                                 ret = r;
 146                                 continue;
 147                         }
 148                         v9ses->debug = option;
 149 #ifdef CONFIG_NET_9P_DEBUG
 150                         p9_debug_level = option;
 151 #endif
 152                         break;
 153
 154                 case Opt_dfltuid:
 155                         r = match_int(&args[0], &option);
 156                         if (r < 0) {
 157                                 P9_DPRINTK(P9_DEBUG_ERROR,
 158                                            "integer field, but no integer?\n");
 159                                 ret = r;
 160                                 continue;
 161                         }
 162                         v9ses->dfltuid = option;
 163                         break;
 164                 case Opt_dfltgid:
 165                         r = match_int(&args[0], &option);
 166                         if (r < 0) {
 167                                 P9_DPRINTK(P9_DEBUG_ERROR,
 168                                            "integer field, but no integer?\n");
 169                                 ret = r;
 170                                 continue;
 171                         }
 172                         v9ses->dfltgid = option;
 173                         break;
 174                 case Opt_afid:
 175                         r = match_int(&args[0], &option);
 176                         if (r < 0) {
 177                                 P9_DPRINTK(P9_DEBUG_ERROR,
 178                                            "integer field, but no integer?\n");
 179                                 ret = r;
 180                                 continue;
 181                         }
 182                         v9ses->afid = option;
 183                         break;
 184                 case Opt_uname:
 185                         match_strlcpy(v9ses->uname, &args[0], PATH_MAX);
 186                         break;
 187                 case Opt_remotename:
 188                         match_strlcpy(v9ses->aname, &args[0], PATH_MAX);
 189                         break;
 190                 case Opt_nodevmap:
 191                         v9ses->nodev = 1;
 192                         break;
 193                 case Opt_cache_loose:
 194                         v9ses->cache = CACHE_LOOSE;
 195                         break;
 196                 case Opt_fscache:
 197                         v9ses->cache = CACHE_FSCACHE;
 198                         break;
 199                 case Opt_cachetag:
 200 #ifdef CONFIG_9P_FSCACHE
 201                         v9ses->cachetag = match_strdup(&args[0]);
 202 #endif
 203                         break;
 204                 case Opt_cache:
 205                         s = match_strdup(&args[0]);
 206                         if (!s) {
 207                                 ret = -ENOMEM;
 208                                 P9_DPRINTK(P9_DEBUG_ERROR,
 209                                   "problem allocating copy of cache arg\n");
 210                                 goto free_and_return;
 211                         }
 212                         ret = get_cache_mode(s);
 213                         if (ret == -EINVAL) {
 214                                 kfree(s);
 215                                 goto free_and_return;
 216                         }
 217
 218                         v9ses->cache = ret;
 219                         kfree(s);
 220                         break;
 221
 222                 case Opt_access:
 223                         s = match_strdup(&args[0]);
 224                         if (!s) {
 225                                 ret = -ENOMEM;
 226                                 P9_DPRINTK(P9_DEBUG_ERROR,
 227                                   "problem allocating copy of access arg\n");
 228                                 goto free_and_return;
 229                         }
 230
 231                         v9ses->flags &= ~V9FS_ACCESS_MASK;
 232                         if (strcmp(s, "user") == 0)
 233                                 v9ses->flags |= V9FS_ACCESS_USER;
 234                         else if (strcmp(s, "any") == 0)
 235                                 v9ses->flags |= V9FS_ACCESS_ANY;
 236                         else if (strcmp(s, "client") == 0) {
 237                                 v9ses->flags |= V9FS_ACCESS_CLIENT;
 238                         } else {
 239                                 v9ses->flags |= V9FS_ACCESS_SINGLE;
 240                                 v9ses->uid = simple_strtoul(s, &e, 10);
 241                                 if (*e != '\0') {
 242                                         ret = -EINVAL;
 243                                         printk(KERN_INFO "9p: Unknown access "
 244                                                         "argument %s.\n", s);
 245                                         kfree(s);
 246                                         goto free_and_return;
 247                                 }
 248                         }
 249
 250                         kfree(s);
 251                         break;
 252
 253                 case Opt_posixacl:
 254 #ifdef CONFIG_9P_FS_POSIX_ACL
 255                         v9ses->flags |= V9FS_POSIX_ACL;
 256 #else
 257                         P9_DPRINTK(P9_DEBUG_ERROR,
 258                                         "Not defined CONFIG_9P_FS_POSIX_ACL. "
 259                                         "Ignoring posixacl option\n");
 260 #endif
 261                         break;
 262
 263                 default:
 264                         continue;
 265                 }
 266         }
 267
 268 free_and_return:
 269         kfree(tmp_options);
 270 fail_option_alloc:
 271         return ret;
 272 }
 273
 274 /**
 275  * v9fs_session_init - initialize session
 276  * @v9ses: session information structure
 277  * @dev_name: device being mounted
 278  * @data: options
 279  *
 280  */
 281
 282 struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
 283                   const char *dev_name, char *data)
 284 {
 285         int retval = -EINVAL;
 286         struct p9_fid *fid;
 287         int rc;
 288
 289         v9ses->uname = __getname();
 290         if (!v9ses->uname)
 291                 return ERR_PTR(-ENOMEM);
 292
 293         v9ses->aname = __getname();
 294         if (!v9ses->aname) {
 295                 __putname(v9ses->uname);
 296                 return ERR_PTR(-ENOMEM);
 297         }
 298         init_rwsem(&v9ses->rename_sem);
 299
 300         rc = bdi_setup_and_register(&v9ses->bdi, "9p", BDI_CAP_MAP_COPY);
 301         if (rc) {
 302                 __putname(v9ses->aname);
 303                 __putname(v9ses->uname);
 304                 return ERR_PTR(rc);
 305         }
 306
 307         spin_lock(&v9fs_sessionlist_lock);
 308         list_add(&v9ses->slist, &v9fs_sessionlist);
 309         spin_unlock(&v9fs_sessionlist_lock);
 310
 311         strcpy(v9ses->uname, V9FS_DEFUSER);
 312         strcpy(v9ses->aname, V9FS_DEFANAME);
 313         v9ses->uid = ~0;
 314         v9ses->dfltuid = V9FS_DEFUID;
 315         v9ses->dfltgid = V9FS_DEFGID;
 316
 317         v9ses->clnt = p9_client_create(dev_name, data);
 318         if (IS_ERR(v9ses->clnt)) {
 319                 retval = PTR_ERR(v9ses->clnt);
 320                 v9ses->clnt = NULL;
 321                 P9_DPRINTK(P9_DEBUG_ERROR, "problem initializing 9p client\n");
 322                 goto error;
 323         }
 324
 325         v9ses->flags = V9FS_ACCESS_USER;
 326
 327         if (p9_is_proto_dotl(v9ses->clnt)) {
 328                 v9ses->flags = V9FS_ACCESS_CLIENT;
 329                 v9ses->flags |= V9FS_PROTO_2000L;
 330         } else if (p9_is_proto_dotu(v9ses->clnt)) {
 331                 v9ses->flags |= V9FS_PROTO_2000U;
 332         }
 333
 334         rc = v9fs_parse_options(v9ses, data);
 335         if (rc < 0) {
 336                 retval = rc;
 337                 goto error;
 338         }
 339
 340         v9ses->maxdata = v9ses->clnt->msize - P9_IOHDRSZ;
 341
 342         if (!v9fs_proto_dotl(v9ses) &&
 343             ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
 344                 /*
 345                  * We support ACCESS_CLIENT only for dotl.
 346                  * Fall back to ACCESS_USER
 347                  */
 348                 v9ses->flags &= ~V9FS_ACCESS_MASK;
 349                 v9ses->flags |= V9FS_ACCESS_USER;
 350         }
 351         /*FIXME !! */
 352         /* for legacy mode, fall back to V9FS_ACCESS_ANY */
 353         if (!(v9fs_proto_dotu(v9ses) || v9fs_proto_dotl(v9ses)) &&
 354                 ((v9ses->flags&V9FS_ACCESS_MASK) == V9FS_ACCESS_USER)) {
 355
 356                 v9ses->flags &= ~V9FS_ACCESS_MASK;
 357                 v9ses->flags |= V9FS_ACCESS_ANY;
 358                 v9ses->uid = ~0;
 359         }
 360         if (!v9fs_proto_dotl(v9ses) ||
 361                 !((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
 362                 /*
 363                  * We support ACL checks on clinet only if the protocol is
 364                  * 9P2000.L and access is V9FS_ACCESS_CLIENT.
 365                  */
 366                 v9ses->flags &= ~V9FS_ACL_MASK;
 367         }
 368
 369         fid = p9_client_attach(v9ses->clnt, NULL, v9ses->uname, ~0,
 370                                                         v9ses->aname);
 371         if (IS_ERR(fid)) {
 372                 retval = PTR_ERR(fid);
 373                 fid = NULL;
 374                 P9_DPRINTK(P9_DEBUG_ERROR, "cannot attach\n");
 375                 goto error;
 376         }
 377
 378         if ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_SINGLE)
 379                 fid->uid = v9ses->uid;
 380         else
 381                 fid->uid = ~0;
 382
 383 #ifdef CONFIG_9P_FSCACHE
 384         /* register the session for caching */
 385         v9fs_cache_session_get_cookie(v9ses);
 386 #endif
 387
 388         return fid;
 389
 390 error:
 391         bdi_destroy(&v9ses->bdi);
 392         return ERR_PTR(retval);
 393 }
 394
 395 /**
 396  * v9fs_session_close - shutdown a session
 397  * @v9ses: session information structure
 398  *
 399  */
 400
 401 void v9fs_session_close(struct v9fs_session_info *v9ses)
 402 {
 403         if (v9ses->clnt) {
 404                 p9_client_destroy(v9ses->clnt);
 405                 v9ses->clnt = NULL;
 406         }
 407
 408 #ifdef CONFIG_9P_FSCACHE
 409         if (v9ses->fscache) {
 410                 v9fs_cache_session_put_cookie(v9ses);
 411                 kfree(v9ses->cachetag);
 412         }
 413 #endif
 414         __putname(v9ses->uname);
 415         __putname(v9ses->aname);
 416
 417         bdi_destroy(&v9ses->bdi);
 418
 419         spin_lock(&v9fs_sessionlist_lock);
 420         list_del(&v9ses->slist);
 421         spin_unlock(&v9fs_sessionlist_lock);
 422 }
 423
 424 /**
 425  * v9fs_session_cancel - terminate a session
 426  * @v9ses: session to terminate
 427  *
 428  * mark transport as disconnected and cancel all pending requests.
 429  */
 430
 431 void v9fs_session_cancel(struct v9fs_session_info *v9ses) {
 432         P9_DPRINTK(P9_DEBUG_ERROR, "cancel session %p\n", v9ses);
 433         p9_client_disconnect(v9ses->clnt);
 434 }
 435
 436 /**
 437  * v9fs_session_begin_cancel - Begin terminate of a session
 438  * @v9ses: session to terminate
 439  *
 440  * After this call we don't allow any request other than clunk.
 441  */
 442
 443 void v9fs_session_begin_cancel(struct v9fs_session_info *v9ses)
 444 {
 445         P9_DPRINTK(P9_DEBUG_ERROR, "begin cancel session %p\n", v9ses);
 446         p9_client_begin_disconnect(v9ses->clnt);
 447 }
 448
 449 extern int v9fs_error_init(void);
 450
 451 static struct kobject *v9fs_kobj;
 452
 453 #ifdef CONFIG_9P_FSCACHE
 454 /**
 455  * caches_show - list caches associated with a session
 456  *
 457  * Returns the size of buffer written.
 458  */
 459
 460 static ssize_t caches_show(struct kobject *kobj,
 461                            struct kobj_attribute *attr,
 462                            char *buf)
 463 {
 464         ssize_t n = 0, count = 0, limit = PAGE_SIZE;
 465         struct v9fs_session_info *v9ses;
 466
 467         spin_lock(&v9fs_sessionlist_lock);
 468         list_for_each_entry(v9ses, &v9fs_sessionlist, slist) {
 469                 if (v9ses->cachetag) {
 470                         n = snprintf(buf, limit, "%s\n", v9ses->cachetag);
 471                         if (n < 0) {
 472                                 count = n;
 473                                 break;
 474                         }
 475
 476                         count += n;
 477                         limit -= n;
 478                 }
 479         }
 480
 481         spin_unlock(&v9fs_sessionlist_lock);
 482         return count;
 483 }
 484
 485 static struct kobj_attribute v9fs_attr_cache = __ATTR_RO(caches);
 486 #endif /* CONFIG_9P_FSCACHE */
 487
 488 static struct attribute *v9fs_attrs[] = {
 489 #ifdef CONFIG_9P_FSCACHE
 490         &v9fs_attr_cache.attr,
 491 #endif
 492         NULL,
 493 };
 494
 495 static struct attribute_group v9fs_attr_group = {
 496         .attrs = v9fs_attrs,
 497 };
 498
 499 /**
 500  * v9fs_sysfs_init - Initialize the v9fs sysfs interface
 501  *
 502  */
 503
 504 static int v9fs_sysfs_init(void)
 505 {
 506         v9fs_kobj = kobject_create_and_add("9p", fs_kobj);
 507         if (!v9fs_kobj)
 508                 return -ENOMEM;
 509
 510         if (sysfs_create_group(v9fs_kobj, &v9fs_attr_group)) {
 511                 kobject_put(v9fs_kobj);
 512                 return -ENOMEM;
 513         }
 514
 515         return 0;
 516 }
 517
 518 /**
 519  * v9fs_sysfs_cleanup - Unregister the v9fs sysfs interface
 520  *
 521  */
 522
 523 static void v9fs_sysfs_cleanup(void)
 524 {
 525         sysfs_remove_group(v9fs_kobj, &v9fs_attr_group);
 526         kobject_put(v9fs_kobj);
 527 }
 528
 529 static void v9fs_inode_init_once(void *foo)
 530 {
 531         struct v9fs_inode *v9inode = (struct v9fs_inode *)foo;
 532 #ifdef CONFIG_9P_FSCACHE
 533         v9inode->fscache = NULL;
 534 #endif
 535         memset(&v9inode->qid, 0, sizeof(v9inode->qid));
 536         inode_init_once(&v9inode->vfs_inode);
 537 }
 538
 539 /**
 540  * v9fs_init_inode_cache - initialize a cache for 9P
 541  * Returns 0 on success.
 542  */
 543 static int v9fs_init_inode_cache(void)
 544 {
 545         v9fs_inode_cache = kmem_cache_create("v9fs_inode_cache",
 546                                           sizeof(struct v9fs_inode),
 547                                           0, (SLAB_RECLAIM_ACCOUNT|
 548                                               SLAB_MEM_SPREAD),
 549                                           v9fs_inode_init_once);
 550         if (!v9fs_inode_cache)
 551                 return -ENOMEM;
 552
 553         return 0;
 554 }
 555
 556 /**
 557  * v9fs_destroy_inode_cache - destroy the cache of 9P inode
 558  *
 559  */
 560 static void v9fs_destroy_inode_cache(void)
 561 {
 562         kmem_cache_destroy(v9fs_inode_cache);
 563 }
 564
 565 static int v9fs_cache_register(void)
 566 {
 567         int ret;
 568         ret = v9fs_init_inode_cache();
 569         if (ret < 0)
 570                 return ret;
 571 #ifdef CONFIG_9P_FSCACHE
 572         return fscache_register_netfs(&v9fs_cache_netfs);
 573 #else
 574         return ret;
 575 #endif
 576 }
 577
 578 static void v9fs_cache_unregister(void)
 579 {
 580         v9fs_destroy_inode_cache();
 581 #ifdef CONFIG_9P_FSCACHE
 582         fscache_unregister_netfs(&v9fs_cache_netfs);
 583 #endif
 584 }
 585
 586 /**
 587  * init_v9fs - Initialize module
 588  *
 589  */
 590
 591 static int __init init_v9fs(void)
 592 {
 593         int err;
 594         printk(KERN_INFO "Installing v9fs 9p2000 file system support\n");
 595         /* TODO: Setup list of registered trasnport modules */
 596         err = register_filesystem(&v9fs_fs_type);
 597         if (err < 0) {
 598                 printk(KERN_ERR "Failed to register filesystem\n");
 599                 return err;
 600         }
 601
 602         err = v9fs_cache_register();
 603         if (err < 0) {
 604                 printk(KERN_ERR "Failed to register v9fs for caching\n");
 605                 goto out_fs_unreg;
 606         }
 607
 608         err = v9fs_sysfs_init();
 609         if (err < 0) {
 610                 printk(KERN_ERR "Failed to register with sysfs\n");
 611                 goto out_sysfs_cleanup;
 612         }
 613
 614         return 0;
 615
 616 out_sysfs_cleanup:
 617         v9fs_sysfs_cleanup();
 618
 619 out_fs_unreg:
 620         unregister_filesystem(&v9fs_fs_type);
 621
 622         return err;
 623 }
 624
 625 /**
 626  * exit_v9fs - shutdown module
 627  *
 628  */
 629
 630 static void __exit exit_v9fs(void)
 631 {
 632         v9fs_sysfs_cleanup();
 633         v9fs_cache_unregister();
 634         unregister_filesystem(&v9fs_fs_type);
 635 }
 636
 637 module_init(init_v9fs)
 638 module_exit(exit_v9fs)
 639
 640 MODULE_AUTHOR("Latchesar Ionkov <[email protected]>");
 641 MODULE_AUTHOR("Eric Van Hensbergen <[email protected]>");
 642 MODULE_AUTHOR("Ron Minnich <[email protected]>");
 643 MODULE_LICENSE("GPL");