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
  43 /*
  44  * Option Parsing (code inspired by NFS code)
  45  *  NOTE: each transport will parse its own options
  46  */
  47
  48 enum {
  49         /* Options that take integer arguments */
  50         Opt_debug, Opt_dfltuid, Opt_dfltgid, Opt_afid,
  51         /* String options */
  52         Opt_uname, Opt_remotename, Opt_trans, Opt_cache, Opt_cachetag,
  53         /* Options that take no arguments */
  54         Opt_nodevmap,
  55         /* Cache options */
  56         Opt_cache_loose, Opt_fscache,
  57         /* Access options */
  58         Opt_access, Opt_posixacl,
  59         /* Error token */
  60         Opt_err
  61 };
  62
  63 static const match_table_t tokens = {
  64         {Opt_debug, "debug=%x"},
  65         {Opt_dfltuid, "dfltuid=%u"},
  66         {Opt_dfltgid, "dfltgid=%u"},
  67         {Opt_afid, "afid=%u"},
  68         {Opt_uname, "uname=%s"},
  69         {Opt_remotename, "aname=%s"},
  70         {Opt_nodevmap, "nodevmap"},
  71         {Opt_cache, "cache=%s"},
  72         {Opt_cache_loose, "loose"},
  73         {Opt_fscache, "fscache"},
  74         {Opt_cachetag, "cachetag=%s"},
  75         {Opt_access, "access=%s"},
  76         {Opt_posixacl, "posixacl"},
  77         {Opt_err, NULL}
  78 };
  79
  80 /**
  81  * v9fs_parse_options - parse mount options into session structure
  82  * @v9ses: existing v9fs session information
  83  *
  84  * Return 0 upon success, -ERRNO upon failure.
  85  */
  86
  87 static int v9fs_parse_options(struct v9fs_session_info *v9ses, char *opts)
  88 {
  89         char *options, *tmp_options;
  90         substring_t args[MAX_OPT_ARGS];
  91         char *p;
  92         int option = 0;
  93         char *s, *e;
  94         int ret = 0;
  95
  96         /* setup defaults */
  97         v9ses->afid = ~0;
  98         v9ses->debug = 0;
  99         v9ses->cache = 0;
 100 #ifdef CONFIG_9P_FSCACHE
 101         v9ses->cachetag = NULL;
 102 #endif
 103
 104         if (!opts)
 105                 return 0;
 106
 107         tmp_options = kstrdup(opts, GFP_KERNEL);
 108         if (!tmp_options) {
 109                 ret = -ENOMEM;
 110                 goto fail_option_alloc;
 111         }
 112         options = tmp_options;
 113
 114         while ((p = strsep(&options, ",")) != NULL) {
 115                 int token;
 116                 if (!*p)
 117                         continue;
 118                 token = match_token(p, tokens, args);
 119                 if (token < Opt_uname) {
 120                         int r = match_int(&args[0], &option);
 121                         if (r < 0) {
 122                                 P9_DPRINTK(P9_DEBUG_ERROR,
 123                                         "integer field, but no integer?\n");
 124                                 ret = r;
 125                                 continue;
 126                         }
 127                 }
 128                 switch (token) {
 129                 case Opt_debug:
 130                         v9ses->debug = option;
 131 #ifdef CONFIG_NET_9P_DEBUG
 132                         p9_debug_level = option;
 133 #endif
 134                         break;
 135
 136                 case Opt_dfltuid:
 137                         v9ses->dfltuid = option;
 138                         break;
 139                 case Opt_dfltgid:
 140                         v9ses->dfltgid = option;
 141                         break;
 142                 case Opt_afid:
 143                         v9ses->afid = option;
 144                         break;
 145                 case Opt_uname:
 146                         match_strlcpy(v9ses->uname, &args[0], PATH_MAX);
 147                         break;
 148                 case Opt_remotename:
 149                         match_strlcpy(v9ses->aname, &args[0], PATH_MAX);
 150                         break;
 151                 case Opt_nodevmap:
 152                         v9ses->nodev = 1;
 153                         break;
 154                 case Opt_cache_loose:
 155                         v9ses->cache = CACHE_LOOSE;
 156                         break;
 157                 case Opt_fscache:
 158                         v9ses->cache = CACHE_FSCACHE;
 159                         break;
 160                 case Opt_cachetag:
 161 #ifdef CONFIG_9P_FSCACHE
 162                         v9ses->cachetag = match_strdup(&args[0]);
 163 #endif
 164                         break;
 165                 case Opt_cache:
 166                         s = match_strdup(&args[0]);
 167                         if (!s) {
 168                                 ret = -ENOMEM;
 169                                 P9_DPRINTK(P9_DEBUG_ERROR,
 170                                   "problem allocating copy of cache arg\n");
 171                                 goto free_and_return;
 172                         }
 173
 174                         if (strcmp(s, "loose") == 0)
 175                                 v9ses->cache = CACHE_LOOSE;
 176                         else if (strcmp(s, "fscache") == 0)
 177                                 v9ses->cache = CACHE_FSCACHE;
 178                         else
 179                                 v9ses->cache = CACHE_NONE;
 180                         kfree(s);
 181                         break;
 182
 183                 case Opt_access:
 184                         s = match_strdup(&args[0]);
 185                         if (!s) {
 186                                 ret = -ENOMEM;
 187                                 P9_DPRINTK(P9_DEBUG_ERROR,
 188                                   "problem allocating copy of access arg\n");
 189                                 goto free_and_return;
 190                         }
 191
 192                         v9ses->flags &= ~V9FS_ACCESS_MASK;
 193                         if (strcmp(s, "user") == 0)
 194                                 v9ses->flags |= V9FS_ACCESS_USER;
 195                         else if (strcmp(s, "any") == 0)
 196                                 v9ses->flags |= V9FS_ACCESS_ANY;
 197                         else if (strcmp(s, "client") == 0) {
 198                                 v9ses->flags |= V9FS_ACCESS_CLIENT;
 199                         } else {
 200                                 v9ses->flags |= V9FS_ACCESS_SINGLE;
 201                                 v9ses->uid = simple_strtoul(s, &e, 10);
 202                                 if (*e != '\0')
 203                                         v9ses->uid = ~0;
 204                         }
 205                         kfree(s);
 206                         break;
 207
 208                 case Opt_posixacl:
 209 #ifdef CONFIG_9P_FS_POSIX_ACL
 210                         v9ses->flags |= V9FS_POSIX_ACL;
 211 #else
 212                         P9_DPRINTK(P9_DEBUG_ERROR,
 213                                         "Not defined CONFIG_9P_FS_POSIX_ACL. "
 214                                         "Ignoring posixacl option\n");
 215 #endif
 216                         break;
 217
 218                 default:
 219                         continue;
 220                 }
 221         }
 222
 223 free_and_return:
 224         kfree(tmp_options);
 225 fail_option_alloc:
 226         return ret;
 227 }
 228
 229 /**
 230  * v9fs_session_init - initialize session
 231  * @v9ses: session information structure
 232  * @dev_name: device being mounted
 233  * @data: options
 234  *
 235  */
 236
 237 struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
 238                   const char *dev_name, char *data)
 239 {
 240         int retval = -EINVAL;
 241         struct p9_fid *fid;
 242         int rc;
 243
 244         v9ses->uname = __getname();
 245         if (!v9ses->uname)
 246                 return ERR_PTR(-ENOMEM);
 247
 248         v9ses->aname = __getname();
 249         if (!v9ses->aname) {
 250                 __putname(v9ses->uname);
 251                 return ERR_PTR(-ENOMEM);
 252         }
 253         init_rwsem(&v9ses->rename_sem);
 254
 255         rc = bdi_setup_and_register(&v9ses->bdi, "9p", BDI_CAP_MAP_COPY);
 256         if (rc) {
 257                 __putname(v9ses->aname);
 258                 __putname(v9ses->uname);
 259                 return ERR_PTR(rc);
 260         }
 261
 262         spin_lock(&v9fs_sessionlist_lock);
 263         list_add(&v9ses->slist, &v9fs_sessionlist);
 264         spin_unlock(&v9fs_sessionlist_lock);
 265
 266         strcpy(v9ses->uname, V9FS_DEFUSER);
 267         strcpy(v9ses->aname, V9FS_DEFANAME);
 268         v9ses->uid = ~0;
 269         v9ses->dfltuid = V9FS_DEFUID;
 270         v9ses->dfltgid = V9FS_DEFGID;
 271
 272         v9ses->clnt = p9_client_create(dev_name, data);
 273         if (IS_ERR(v9ses->clnt)) {
 274                 retval = PTR_ERR(v9ses->clnt);
 275                 v9ses->clnt = NULL;
 276                 P9_DPRINTK(P9_DEBUG_ERROR, "problem initializing 9p client\n");
 277                 goto error;
 278         }
 279
 280         v9ses->flags = V9FS_ACCESS_USER;
 281
 282         if (p9_is_proto_dotl(v9ses->clnt)) {
 283                 v9ses->flags = V9FS_ACCESS_CLIENT;
 284                 v9ses->flags |= V9FS_PROTO_2000L;
 285         } else if (p9_is_proto_dotu(v9ses->clnt)) {
 286                 v9ses->flags |= V9FS_PROTO_2000U;
 287         }
 288
 289         rc = v9fs_parse_options(v9ses, data);
 290         if (rc < 0) {
 291                 retval = rc;
 292                 goto error;
 293         }
 294
 295         v9ses->maxdata = v9ses->clnt->msize - P9_IOHDRSZ;
 296
 297         if (!v9fs_proto_dotl(v9ses) &&
 298             ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
 299                 /*
 300                  * We support ACCESS_CLIENT only for dotl.
 301                  * Fall back to ACCESS_USER
 302                  */
 303                 v9ses->flags &= ~V9FS_ACCESS_MASK;
 304                 v9ses->flags |= V9FS_ACCESS_USER;
 305         }
 306         /*FIXME !! */
 307         /* for legacy mode, fall back to V9FS_ACCESS_ANY */
 308         if (!(v9fs_proto_dotu(v9ses) || v9fs_proto_dotl(v9ses)) &&
 309                 ((v9ses->flags&V9FS_ACCESS_MASK) == V9FS_ACCESS_USER)) {
 310
 311                 v9ses->flags &= ~V9FS_ACCESS_MASK;
 312                 v9ses->flags |= V9FS_ACCESS_ANY;
 313                 v9ses->uid = ~0;
 314         }
 315         if (!v9fs_proto_dotl(v9ses) ||
 316                 !((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
 317                 /*
 318                  * We support ACL checks on clinet only if the protocol is
 319                  * 9P2000.L and access is V9FS_ACCESS_CLIENT.
 320                  */
 321                 v9ses->flags &= ~V9FS_ACL_MASK;
 322         }
 323
 324         fid = p9_client_attach(v9ses->clnt, NULL, v9ses->uname, ~0,
 325                                                         v9ses->aname);
 326         if (IS_ERR(fid)) {
 327                 retval = PTR_ERR(fid);
 328                 fid = NULL;
 329                 P9_DPRINTK(P9_DEBUG_ERROR, "cannot attach\n");
 330                 goto error;
 331         }
 332
 333         if ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_SINGLE)
 334                 fid->uid = v9ses->uid;
 335         else
 336                 fid->uid = ~0;
 337
 338 #ifdef CONFIG_9P_FSCACHE
 339         /* register the session for caching */
 340         v9fs_cache_session_get_cookie(v9ses);
 341 #endif
 342
 343         return fid;
 344
 345 error:
 346         bdi_destroy(&v9ses->bdi);
 347         return ERR_PTR(retval);
 348 }
 349
 350 /**
 351  * v9fs_session_close - shutdown a session
 352  * @v9ses: session information structure
 353  *
 354  */
 355
 356 void v9fs_session_close(struct v9fs_session_info *v9ses)
 357 {
 358         if (v9ses->clnt) {
 359                 p9_client_destroy(v9ses->clnt);
 360                 v9ses->clnt = NULL;
 361         }
 362
 363 #ifdef CONFIG_9P_FSCACHE
 364         if (v9ses->fscache) {
 365                 v9fs_cache_session_put_cookie(v9ses);
 366                 kfree(v9ses->cachetag);
 367         }
 368 #endif
 369         __putname(v9ses->uname);
 370         __putname(v9ses->aname);
 371
 372         bdi_destroy(&v9ses->bdi);
 373
 374         spin_lock(&v9fs_sessionlist_lock);
 375         list_del(&v9ses->slist);
 376         spin_unlock(&v9fs_sessionlist_lock);
 377 }
 378
 379 /**
 380  * v9fs_session_cancel - terminate a session
 381  * @v9ses: session to terminate
 382  *
 383  * mark transport as disconnected and cancel all pending requests.
 384  */
 385
 386 void v9fs_session_cancel(struct v9fs_session_info *v9ses) {
 387         P9_DPRINTK(P9_DEBUG_ERROR, "cancel session %p\n", v9ses);
 388         p9_client_disconnect(v9ses->clnt);
 389 }
 390
 391 /**
 392  * v9fs_session_begin_cancel - Begin terminate of a session
 393  * @v9ses: session to terminate
 394  *
 395  * After this call we don't allow any request other than clunk.
 396  */
 397
 398 void v9fs_session_begin_cancel(struct v9fs_session_info *v9ses)
 399 {
 400         P9_DPRINTK(P9_DEBUG_ERROR, "begin cancel session %p\n", v9ses);
 401         p9_client_begin_disconnect(v9ses->clnt);
 402 }
 403
 404 extern int v9fs_error_init(void);
 405
 406 static struct kobject *v9fs_kobj;
 407
 408 #ifdef CONFIG_9P_FSCACHE
 409 /**
 410  * caches_show - list caches associated with a session
 411  *
 412  * Returns the size of buffer written.
 413  */
 414
 415 static ssize_t caches_show(struct kobject *kobj,
 416                            struct kobj_attribute *attr,
 417                            char *buf)
 418 {
 419         ssize_t n = 0, count = 0, limit = PAGE_SIZE;
 420         struct v9fs_session_info *v9ses;
 421
 422         spin_lock(&v9fs_sessionlist_lock);
 423         list_for_each_entry(v9ses, &v9fs_sessionlist, slist) {
 424                 if (v9ses->cachetag) {
 425                         n = snprintf(buf, limit, "%s\n", v9ses->cachetag);
 426                         if (n < 0) {
 427                                 count = n;
 428                                 break;
 429                         }
 430
 431                         count += n;
 432                         limit -= n;
 433                 }
 434         }
 435
 436         spin_unlock(&v9fs_sessionlist_lock);
 437         return count;
 438 }
 439
 440 static struct kobj_attribute v9fs_attr_cache = __ATTR_RO(caches);
 441 #endif /* CONFIG_9P_FSCACHE */
 442
 443 static struct attribute *v9fs_attrs[] = {
 444 #ifdef CONFIG_9P_FSCACHE
 445         &v9fs_attr_cache.attr,
 446 #endif
 447         NULL,
 448 };
 449
 450 static struct attribute_group v9fs_attr_group = {
 451         .attrs = v9fs_attrs,
 452 };
 453
 454 /**
 455  * v9fs_sysfs_init - Initialize the v9fs sysfs interface
 456  *
 457  */
 458
 459 static int v9fs_sysfs_init(void)
 460 {
 461         v9fs_kobj = kobject_create_and_add("9p", fs_kobj);
 462         if (!v9fs_kobj)
 463                 return -ENOMEM;
 464
 465         if (sysfs_create_group(v9fs_kobj, &v9fs_attr_group)) {
 466                 kobject_put(v9fs_kobj);
 467                 return -ENOMEM;
 468         }
 469
 470         return 0;
 471 }
 472
 473 /**
 474  * v9fs_sysfs_cleanup - Unregister the v9fs sysfs interface
 475  *
 476  */
 477
 478 static void v9fs_sysfs_cleanup(void)
 479 {
 480         sysfs_remove_group(v9fs_kobj, &v9fs_attr_group);
 481         kobject_put(v9fs_kobj);
 482 }
 483
 484 /**
 485  * init_v9fs - Initialize module
 486  *
 487  */
 488
 489 static int __init init_v9fs(void)
 490 {
 491         int err;
 492         printk(KERN_INFO "Installing v9fs 9p2000 file system support\n");
 493         /* TODO: Setup list of registered trasnport modules */
 494         err = register_filesystem(&v9fs_fs_type);
 495         if (err < 0) {
 496                 printk(KERN_ERR "Failed to register filesystem\n");
 497                 return err;
 498         }
 499
 500         err = v9fs_cache_register();
 501         if (err < 0) {
 502                 printk(KERN_ERR "Failed to register v9fs for caching\n");
 503                 goto out_fs_unreg;
 504         }
 505
 506         err = v9fs_sysfs_init();
 507         if (err < 0) {
 508                 printk(KERN_ERR "Failed to register with sysfs\n");
 509                 goto out_sysfs_cleanup;
 510         }
 511
 512         return 0;
 513
 514 out_sysfs_cleanup:
 515         v9fs_sysfs_cleanup();
 516
 517 out_fs_unreg:
 518         unregister_filesystem(&v9fs_fs_type);
 519
 520         return err;
 521 }
 522
 523 /**
 524  * exit_v9fs - shutdown module
 525  *
 526  */
 527
 528 static void __exit exit_v9fs(void)
 529 {
 530         v9fs_sysfs_cleanup();
 531         v9fs_cache_unregister();
 532         unregister_filesystem(&v9fs_fs_type);
 533 }
 534
 535 module_init(init_v9fs)
 536 module_exit(exit_v9fs)
 537
 538 MODULE_AUTHOR("Latchesar Ionkov <lucho@ionkov.net>");
 539 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
 540 MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
 541 MODULE_LICENSE("GPL");