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