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                         p9_debug_level = option;
 152                         break;
 153
 154                 case Opt_dfltuid:
 155                         v9ses->dfltuid = option;
 156                         break;
 157                 case Opt_dfltgid:
 158                         v9ses->dfltgid = option;
 159                         break;
 160                 case Opt_afid:
 161                         v9ses->afid = option;
 162                         break;
 163                 case Opt_uname:
 164                         match_strlcpy(v9ses->uname, &args[0], PATH_MAX);
 165                         break;
 166                 case Opt_remotename:
 167                         match_strlcpy(v9ses->aname, &args[0], PATH_MAX);
 168                         break;
 169                 case Opt_nodevmap:
 170                         v9ses->nodev = 1;
 171                         break;
 172                 case Opt_cache_loose:
 173                         v9ses->cache = CACHE_LOOSE;
 174                         break;
 175                 case Opt_fscache:
 176                         v9ses->cache = CACHE_FSCACHE;
 177                         break;
 178                 case Opt_cachetag:
 179 #ifdef CONFIG_9P_FSCACHE
 180                         v9ses->cachetag = match_strdup(&args[0]);
 181 #endif
 182                         break;
 183                 case Opt_cache:
 184                         s = match_strdup(&args[0]);
 185                         if (!s) {
 186                                 ret = -ENOMEM;
 187                                 P9_DPRINTK(P9_DEBUG_ERROR,
 188                                   "problem allocating copy of cache arg\n");
 189                                 goto free_and_return;
 190                         }
 191                         ret = get_cache_mode(s);
 192                         if (ret == -EINVAL) {
 193                                 kfree(s);
 194                                 goto free_and_return;
 195                         }
 196
 197                         v9ses->cache = ret;
 198                         kfree(s);
 199                         break;
 200
 201                 case Opt_access:
 202                         s = match_strdup(&args[0]);
 203                         if (!s) {
 204                                 ret = -ENOMEM;
 205                                 P9_DPRINTK(P9_DEBUG_ERROR,
 206                                   "problem allocating copy of access arg\n");
 207                                 goto free_and_return;
 208                         }
 209
 210                         v9ses->flags &= ~V9FS_ACCESS_MASK;
 211                         if (strcmp(s, "user") == 0)
 212                                 v9ses->flags |= V9FS_ACCESS_USER;
 213                         else if (strcmp(s, "any") == 0)
 214                                 v9ses->flags |= V9FS_ACCESS_ANY;
 215                         else if (strcmp(s, "client") == 0) {
 216                                 v9ses->flags |= V9FS_ACCESS_CLIENT;
 217                         } else {
 218                                 v9ses->flags |= V9FS_ACCESS_SINGLE;
 219                                 v9ses->uid = simple_strtoul(s, &e, 10);
 220                                 if (*e != '\0') {
 221                                         ret = -EINVAL;
 222                                         printk(KERN_INFO "9p: Unknown access "
 223                                                         "argument %s.\n", s);
 224                                         kfree(s);
 225                                         goto free_and_return;
 226                                 }
 227                         }
 228
 229                         kfree(s);
 230                         break;
 231
 232                 case Opt_posixacl:
 233 #ifdef CONFIG_9P_FS_POSIX_ACL
 234                         v9ses->flags |= V9FS_POSIX_ACL;
 235 #else
 236                         P9_DPRINTK(P9_DEBUG_ERROR,
 237                                         "Not defined CONFIG_9P_FS_POSIX_ACL. "
 238                                         "Ignoring posixacl option\n");
 239 #endif
 240                         break;
 241
 242                 default:
 243                         continue;
 244                 }
 245         }
 246
 247 free_and_return:
 248         kfree(tmp_options);
 249 fail_option_alloc:
 250         return ret;
 251 }
 252
 253 /**
 254  * v9fs_session_init - initialize session
 255  * @v9ses: session information structure
 256  * @dev_name: device being mounted
 257  * @data: options
 258  *
 259  */
 260
 261 struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
 262                   const char *dev_name, char *data)
 263 {
 264         int retval = -EINVAL;
 265         struct p9_fid *fid;
 266         int rc;
 267
 268         v9ses->uname = __getname();
 269         if (!v9ses->uname)
 270                 return ERR_PTR(-ENOMEM);
 271
 272         v9ses->aname = __getname();
 273         if (!v9ses->aname) {
 274                 __putname(v9ses->uname);
 275                 return ERR_PTR(-ENOMEM);
 276         }
 277         init_rwsem(&v9ses->rename_sem);
 278
 279         rc = bdi_setup_and_register(&v9ses->bdi, "9p", BDI_CAP_MAP_COPY);
 280         if (rc) {
 281                 __putname(v9ses->aname);
 282                 __putname(v9ses->uname);
 283                 return ERR_PTR(rc);
 284         }
 285
 286         spin_lock(&v9fs_sessionlist_lock);
 287         list_add(&v9ses->slist, &v9fs_sessionlist);
 288         spin_unlock(&v9fs_sessionlist_lock);
 289
 290         strcpy(v9ses->uname, V9FS_DEFUSER);
 291         strcpy(v9ses->aname, V9FS_DEFANAME);
 292         v9ses->uid = ~0;
 293         v9ses->dfltuid = V9FS_DEFUID;
 294         v9ses->dfltgid = V9FS_DEFGID;
 295
 296         v9ses->clnt = p9_client_create(dev_name, data);
 297         if (IS_ERR(v9ses->clnt)) {
 298                 retval = PTR_ERR(v9ses->clnt);
 299                 v9ses->clnt = NULL;
 300                 P9_DPRINTK(P9_DEBUG_ERROR, "problem initializing 9p client\n");
 301                 goto error;
 302         }
 303
 304         v9ses->flags = V9FS_ACCESS_USER;
 305
 306         if (p9_is_proto_dotl(v9ses->clnt)) {
 307                 v9ses->flags = V9FS_ACCESS_CLIENT;
 308                 v9ses->flags |= V9FS_PROTO_2000L;
 309         } else if (p9_is_proto_dotu(v9ses->clnt)) {
 310                 v9ses->flags |= V9FS_PROTO_2000U;
 311         }
 312
 313         rc = v9fs_parse_options(v9ses, data);
 314         if (rc < 0) {
 315                 retval = rc;
 316                 goto error;
 317         }
 318
 319         v9ses->maxdata = v9ses->clnt->msize - P9_IOHDRSZ;
 320
 321         if (!v9fs_proto_dotl(v9ses) &&
 322             ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
 323                 /*
 324                  * We support ACCESS_CLIENT only for dotl.
 325                  * Fall back to ACCESS_USER
 326                  */
 327                 v9ses->flags &= ~V9FS_ACCESS_MASK;
 328                 v9ses->flags |= V9FS_ACCESS_USER;
 329         }
 330         /*FIXME !! */
 331         /* for legacy mode, fall back to V9FS_ACCESS_ANY */
 332         if (!(v9fs_proto_dotu(v9ses) || v9fs_proto_dotl(v9ses)) &&
 333                 ((v9ses->flags&V9FS_ACCESS_MASK) == V9FS_ACCESS_USER)) {
 334
 335                 v9ses->flags &= ~V9FS_ACCESS_MASK;
 336                 v9ses->flags |= V9FS_ACCESS_ANY;
 337                 v9ses->uid = ~0;
 338         }
 339         if (!v9fs_proto_dotl(v9ses) ||
 340                 !((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
 341                 /*
 342                  * We support ACL checks on clinet only if the protocol is
 343                  * 9P2000.L and access is V9FS_ACCESS_CLIENT.
 344                  */
 345                 v9ses->flags &= ~V9FS_ACL_MASK;
 346         }
 347
 348         fid = p9_client_attach(v9ses->clnt, NULL, v9ses->uname, ~0,
 349                                                         v9ses->aname);
 350         if (IS_ERR(fid)) {
 351                 retval = PTR_ERR(fid);
 352                 fid = NULL;
 353                 P9_DPRINTK(P9_DEBUG_ERROR, "cannot attach\n");
 354                 goto error;
 355         }
 356
 357         if ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_SINGLE)
 358                 fid->uid = v9ses->uid;
 359         else
 360                 fid->uid = ~0;
 361
 362 #ifdef CONFIG_9P_FSCACHE
 363         /* register the session for caching */
 364         v9fs_cache_session_get_cookie(v9ses);
 365 #endif
 366
 367         return fid;
 368
 369 error:
 370         bdi_destroy(&v9ses->bdi);
 371         return ERR_PTR(retval);
 372 }
 373
 374 /**
 375  * v9fs_session_close - shutdown a session
 376  * @v9ses: session information structure
 377  *
 378  */
 379
 380 void v9fs_session_close(struct v9fs_session_info *v9ses)
 381 {
 382         if (v9ses->clnt) {
 383                 p9_client_destroy(v9ses->clnt);
 384                 v9ses->clnt = NULL;
 385         }
 386
 387 #ifdef CONFIG_9P_FSCACHE
 388         if (v9ses->fscache) {
 389                 v9fs_cache_session_put_cookie(v9ses);
 390                 kfree(v9ses->cachetag);
 391         }
 392 #endif
 393         __putname(v9ses->uname);
 394         __putname(v9ses->aname);
 395
 396         bdi_destroy(&v9ses->bdi);
 397
 398         spin_lock(&v9fs_sessionlist_lock);
 399         list_del(&v9ses->slist);
 400         spin_unlock(&v9fs_sessionlist_lock);
 401 }
 402
 403 /**
 404  * v9fs_session_cancel - terminate a session
 405  * @v9ses: session to terminate
 406  *
 407  * mark transport as disconnected and cancel all pending requests.
 408  */
 409
 410 void v9fs_session_cancel(struct v9fs_session_info *v9ses) {
 411         P9_DPRINTK(P9_DEBUG_ERROR, "cancel session %p\n", v9ses);
 412         p9_client_disconnect(v9ses->clnt);
 413 }
 414
 415 /**
 416  * v9fs_session_begin_cancel - Begin terminate of a session
 417  * @v9ses: session to terminate
 418  *
 419  * After this call we don't allow any request other than clunk.
 420  */
 421
 422 void v9fs_session_begin_cancel(struct v9fs_session_info *v9ses)
 423 {
 424         P9_DPRINTK(P9_DEBUG_ERROR, "begin cancel session %p\n", v9ses);
 425         p9_client_begin_disconnect(v9ses->clnt);
 426 }
 427
 428 extern int v9fs_error_init(void);
 429
 430 static struct kobject *v9fs_kobj;
 431
 432 #ifdef CONFIG_9P_FSCACHE
 433 /**
 434  * caches_show - list caches associated with a session
 435  *
 436  * Returns the size of buffer written.
 437  */
 438
 439 static ssize_t caches_show(struct kobject *kobj,
 440                            struct kobj_attribute *attr,
 441                            char *buf)
 442 {
 443         ssize_t n = 0, count = 0, limit = PAGE_SIZE;
 444         struct v9fs_session_info *v9ses;
 445
 446         spin_lock(&v9fs_sessionlist_lock);
 447         list_for_each_entry(v9ses, &v9fs_sessionlist, slist) {
 448                 if (v9ses->cachetag) {
 449                         n = snprintf(buf, limit, "%s\n", v9ses->cachetag);
 450                         if (n < 0) {
 451                                 count = n;
 452                                 break;
 453                         }
 454
 455                         count += n;
 456                         limit -= n;
 457                 }
 458         }
 459
 460         spin_unlock(&v9fs_sessionlist_lock);
 461         return count;
 462 }
 463
 464 static struct kobj_attribute v9fs_attr_cache = __ATTR_RO(caches);
 465 #endif /* CONFIG_9P_FSCACHE */
 466
 467 static struct attribute *v9fs_attrs[] = {
 468 #ifdef CONFIG_9P_FSCACHE
 469         &v9fs_attr_cache.attr,
 470 #endif
 471         NULL,
 472 };
 473
 474 static struct attribute_group v9fs_attr_group = {
 475         .attrs = v9fs_attrs,
 476 };
 477
 478 /**
 479  * v9fs_sysfs_init - Initialize the v9fs sysfs interface
 480  *
 481  */
 482
 483 static int v9fs_sysfs_init(void)
 484 {
 485         v9fs_kobj = kobject_create_and_add("9p", fs_kobj);
 486         if (!v9fs_kobj)
 487                 return -ENOMEM;
 488
 489         if (sysfs_create_group(v9fs_kobj, &v9fs_attr_group)) {
 490                 kobject_put(v9fs_kobj);
 491                 return -ENOMEM;
 492         }
 493
 494         return 0;
 495 }
 496
 497 /**
 498  * v9fs_sysfs_cleanup - Unregister the v9fs sysfs interface
 499  *
 500  */
 501
 502 static void v9fs_sysfs_cleanup(void)
 503 {
 504         sysfs_remove_group(v9fs_kobj, &v9fs_attr_group);
 505         kobject_put(v9fs_kobj);
 506 }
 507
 508 static void v9fs_inode_init_once(void *foo)
 509 {
 510         struct v9fs_inode *v9inode = (struct v9fs_inode *)foo;
 511 #ifdef CONFIG_9P_FSCACHE
 512         v9inode->fscache = NULL;
 513 #endif
 514         memset(&v9inode->qid, 0, sizeof(v9inode->qid));
 515         inode_init_once(&v9inode->vfs_inode);
 516 }
 517
 518 /**
 519  * v9fs_init_inode_cache - initialize a cache for 9P
 520  * Returns 0 on success.
 521  */
 522 static int v9fs_init_inode_cache(void)
 523 {
 524         v9fs_inode_cache = kmem_cache_create("v9fs_inode_cache",
 525                                           sizeof(struct v9fs_inode),
 526                                           0, (SLAB_RECLAIM_ACCOUNT|
 527                                               SLAB_MEM_SPREAD),
 528                                           v9fs_inode_init_once);
 529         if (!v9fs_inode_cache)
 530                 return -ENOMEM;
 531
 532         return 0;
 533 }
 534
 535 /**
 536  * v9fs_destroy_inode_cache - destroy the cache of 9P inode
 537  *
 538  */
 539 static void v9fs_destroy_inode_cache(void)
 540 {
 541         kmem_cache_destroy(v9fs_inode_cache);
 542 }
 543
 544 static int v9fs_cache_register(void)
 545 {
 546         int ret;
 547         ret = v9fs_init_inode_cache();
 548         if (ret < 0)
 549                 return ret;
 550 #ifdef CONFIG_9P_FSCACHE
 551         return fscache_register_netfs(&v9fs_cache_netfs);
 552 #else
 553         return ret;
 554 #endif
 555 }
 556
 557 static void v9fs_cache_unregister(void)
 558 {
 559         v9fs_destroy_inode_cache();
 560 #ifdef CONFIG_9P_FSCACHE
 561         fscache_unregister_netfs(&v9fs_cache_netfs);
 562 #endif
 563 }
 564
 565 /**
 566  * init_v9fs - Initialize module
 567  *
 568  */
 569
 570 static int __init init_v9fs(void)
 571 {
 572         int err;
 573         printk(KERN_INFO "Installing v9fs 9p2000 file system support\n");
 574         /* TODO: Setup list of registered trasnport modules */
 575         err = register_filesystem(&v9fs_fs_type);
 576         if (err < 0) {
 577                 printk(KERN_ERR "Failed to register filesystem\n");
 578                 return err;
 579         }
 580
 581         err = v9fs_cache_register();
 582         if (err < 0) {
 583                 printk(KERN_ERR "Failed to register v9fs for caching\n");
 584                 goto out_fs_unreg;
 585         }
 586
 587         err = v9fs_sysfs_init();
 588         if (err < 0) {
 589                 printk(KERN_ERR "Failed to register with sysfs\n");
 590                 goto out_sysfs_cleanup;
 591         }
 592
 593         return 0;
 594
 595 out_sysfs_cleanup:
 596         v9fs_sysfs_cleanup();
 597
 598 out_fs_unreg:
 599         unregister_filesystem(&v9fs_fs_type);
 600
 601         return err;
 602 }
 603
 604 /**
 605  * exit_v9fs - shutdown module
 606  *
 607  */
 608
 609 static void __exit exit_v9fs(void)
 610 {
 611         v9fs_sysfs_cleanup();
 612         v9fs_cache_unregister();
 613         unregister_filesystem(&v9fs_fs_type);
 614 }
 615
 616 module_init(init_v9fs)
 617 module_exit(exit_v9fs)
 618
 619 MODULE_AUTHOR("Latchesar Ionkov <lucho@ionkov.net>");
 620 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
 621 MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
 622 MODULE_LICENSE("GPL");