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