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 <net/9p/9p.h>
  33 #include <net/9p/client.h>
  34 #include <net/9p/transport.h>
  35 #include "v9fs.h"
  36 #include "v9fs_vfs.h"
  37 #include "cache.h"
  38
  39 static DEFINE_SPINLOCK(v9fs_sessionlist_lock);
  40 static LIST_HEAD(v9fs_sessionlist);
  41
  42 /*
  43  * Option Parsing (code inspired by NFS code)
  44  *  NOTE: each transport will parse its own options
  45  */
  46
  47 enum {
  48         /* Options that take integer arguments */
  49         Opt_debug, Opt_dfltuid, Opt_dfltgid, Opt_afid,
  50         /* String options */
  51         Opt_uname, Opt_remotename, Opt_trans, Opt_cache, Opt_cachetag,
  52         /* Options that take no arguments */
  53         Opt_nodevmap,
  54         /* Cache options */
  55         Opt_cache_loose, Opt_fscache,
  56         /* Access options */
  57         Opt_access,
  58         /* Error token */
  59         Opt_err
  60 };
  61
  62 static const match_table_t tokens = {
  63         {Opt_debug, "debug=%x"},
  64         {Opt_dfltuid, "dfltuid=%u"},
  65         {Opt_dfltgid, "dfltgid=%u"},
  66         {Opt_afid, "afid=%u"},
  67         {Opt_uname, "uname=%s"},
  68         {Opt_remotename, "aname=%s"},
  69         {Opt_nodevmap, "nodevmap"},
  70         {Opt_cache, "cache=%s"},
  71         {Opt_cache_loose, "loose"},
  72         {Opt_fscache, "fscache"},
  73         {Opt_cachetag, "cachetag=%s"},
  74         {Opt_access, "access=%s"},
  75         {Opt_err, NULL}
  76 };
  77
  78 /**
  79  * v9fs_parse_options - parse mount options into session structure
  80  * @v9ses: existing v9fs session information
  81  *
  82  * Return 0 upon success, -ERRNO upon failure.
  83  */
  84
  85 static int v9fs_parse_options(struct v9fs_session_info *v9ses, char *opts)
  86 {
  87         char *options, *tmp_options;
  88         substring_t args[MAX_OPT_ARGS];
  89         char *p;
  90         int option = 0;
  91         char *s, *e;
  92         int ret = 0;
  93
  94         /* setup defaults */
  95         v9ses->afid = ~0;
  96         v9ses->debug = 0;
  97         v9ses->cache = 0;
  98 #ifdef CONFIG_9P_FSCACHE
  99         v9ses->cachetag = NULL;
 100 #endif
 101
 102         if (!opts)
 103                 return 0;
 104
 105         tmp_options = kstrdup(opts, GFP_KERNEL);
 106         if (!tmp_options) {
 107                 ret = -ENOMEM;
 108                 goto fail_option_alloc;
 109         }
 110         options = tmp_options;
 111
 112         while ((p = strsep(&options, ",")) != NULL) {
 113                 int token;
 114                 if (!*p)
 115                         continue;
 116                 token = match_token(p, tokens, args);
 117                 if (token < Opt_uname) {
 118                         int r = match_int(&args[0], &option);
 119                         if (r < 0) {
 120                                 P9_DPRINTK(P9_DEBUG_ERROR,
 121                                         "integer field, but no integer?\n");
 122                                 ret = r;
 123                                 continue;
 124                         }
 125                 }
 126                 switch (token) {
 127                 case Opt_debug:
 128                         v9ses->debug = option;
 129 #ifdef CONFIG_NET_9P_DEBUG
 130                         p9_debug_level = option;
 131 #endif
 132                         break;
 133
 134                 case Opt_dfltuid:
 135                         v9ses->dfltuid = option;
 136                         break;
 137                 case Opt_dfltgid:
 138                         v9ses->dfltgid = option;
 139                         break;
 140                 case Opt_afid:
 141                         v9ses->afid = option;
 142                         break;
 143                 case Opt_uname:
 144                         match_strlcpy(v9ses->uname, &args[0], PATH_MAX);
 145                         break;
 146                 case Opt_remotename:
 147                         match_strlcpy(v9ses->aname, &args[0], PATH_MAX);
 148                         break;
 149                 case Opt_nodevmap:
 150                         v9ses->nodev = 1;
 151                         break;
 152                 case Opt_cache_loose:
 153                         v9ses->cache = CACHE_LOOSE;
 154                         break;
 155                 case Opt_fscache:
 156                         v9ses->cache = CACHE_FSCACHE;
 157                         break;
 158                 case Opt_cachetag:
 159 #ifdef CONFIG_9P_FSCACHE
 160                         v9ses->cachetag = match_strdup(&args[0]);
 161 #endif
 162                         break;
 163                 case Opt_cache:
 164                         s = match_strdup(&args[0]);
 165                         if (!s) {
 166                                 ret = -ENOMEM;
 167                                 P9_DPRINTK(P9_DEBUG_ERROR,
 168                                   "problem allocating copy of cache arg\n");
 169                                 goto free_and_return;
 170                         }
 171
 172                         if (strcmp(s, "loose") == 0)
 173                                 v9ses->cache = CACHE_LOOSE;
 174                         else if (strcmp(s, "fscache") == 0)
 175                                 v9ses->cache = CACHE_FSCACHE;
 176                         else
 177                                 v9ses->cache = CACHE_NONE;
 178                         kfree(s);
 179                         break;
 180
 181                 case Opt_access:
 182                         s = match_strdup(&args[0]);
 183                         if (!s) {
 184                                 ret = -ENOMEM;
 185                                 P9_DPRINTK(P9_DEBUG_ERROR,
 186                                   "problem allocating copy of access arg\n");
 187                                 goto free_and_return;
 188                         }
 189
 190                         v9ses->flags &= ~V9FS_ACCESS_MASK;
 191                         if (strcmp(s, "user") == 0)
 192                                 v9ses->flags |= V9FS_ACCESS_USER;
 193                         else if (strcmp(s, "any") == 0)
 194                                 v9ses->flags |= V9FS_ACCESS_ANY;
 195                         else {
 196                                 v9ses->flags |= V9FS_ACCESS_SINGLE;
 197                                 v9ses->uid = simple_strtoul(s, &e, 10);
 198                                 if (*e != '\0')
 199                                         v9ses->uid = ~0;
 200                         }
 201                         kfree(s);
 202                         break;
 203
 204                 default:
 205                         continue;
 206                 }
 207         }
 208
 209 free_and_return:
 210         kfree(tmp_options);
 211 fail_option_alloc:
 212         return ret;
 213 }
 214
 215 /**
 216  * v9fs_session_init - initialize session
 217  * @v9ses: session information structure
 218  * @dev_name: device being mounted
 219  * @data: options
 220  *
 221  */
 222
 223 struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
 224                   const char *dev_name, char *data)
 225 {
 226         int retval = -EINVAL;
 227         struct p9_fid *fid;
 228         int rc;
 229
 230         v9ses->uname = __getname();
 231         if (!v9ses->uname)
 232                 return ERR_PTR(-ENOMEM);
 233
 234         v9ses->aname = __getname();
 235         if (!v9ses->aname) {
 236                 __putname(v9ses->uname);
 237                 return ERR_PTR(-ENOMEM);
 238         }
 239
 240         spin_lock(&v9fs_sessionlist_lock);
 241         list_add(&v9ses->slist, &v9fs_sessionlist);
 242         spin_unlock(&v9fs_sessionlist_lock);
 243
 244         v9ses->flags = V9FS_EXTENDED | V9FS_ACCESS_USER;
 245         strcpy(v9ses->uname, V9FS_DEFUSER);
 246         strcpy(v9ses->aname, V9FS_DEFANAME);
 247         v9ses->uid = ~0;
 248         v9ses->dfltuid = V9FS_DEFUID;
 249         v9ses->dfltgid = V9FS_DEFGID;
 250
 251         rc = v9fs_parse_options(v9ses, data);
 252         if (rc < 0) {
 253                 retval = rc;
 254                 goto error;
 255         }
 256
 257         v9ses->clnt = p9_client_create(dev_name, data);
 258         if (IS_ERR(v9ses->clnt)) {
 259                 retval = PTR_ERR(v9ses->clnt);
 260                 v9ses->clnt = NULL;
 261                 P9_DPRINTK(P9_DEBUG_ERROR, "problem initializing 9p client\n");
 262                 goto error;
 263         }
 264
 265         if (!v9ses->clnt->dotu)
 266                 v9ses->flags &= ~V9FS_EXTENDED;
 267
 268         v9ses->maxdata = v9ses->clnt->msize - P9_IOHDRSZ;
 269
 270         /* for legacy mode, fall back to V9FS_ACCESS_ANY */
 271         if (!v9fs_extended(v9ses) &&
 272                 ((v9ses->flags&V9FS_ACCESS_MASK) == V9FS_ACCESS_USER)) {
 273
 274                 v9ses->flags &= ~V9FS_ACCESS_MASK;
 275                 v9ses->flags |= V9FS_ACCESS_ANY;
 276                 v9ses->uid = ~0;
 277         }
 278
 279         fid = p9_client_attach(v9ses->clnt, NULL, v9ses->uname, ~0,
 280                                                         v9ses->aname);
 281         if (IS_ERR(fid)) {
 282                 retval = PTR_ERR(fid);
 283                 fid = NULL;
 284                 P9_DPRINTK(P9_DEBUG_ERROR, "cannot attach\n");
 285                 goto error;
 286         }
 287
 288         if ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_SINGLE)
 289                 fid->uid = v9ses->uid;
 290         else
 291                 fid->uid = ~0;
 292
 293 #ifdef CONFIG_9P_FSCACHE
 294         /* register the session for caching */
 295         v9fs_cache_session_get_cookie(v9ses);
 296 #endif
 297
 298         return fid;
 299
 300 error:
 301         return ERR_PTR(retval);
 302 }
 303
 304 /**
 305  * v9fs_session_close - shutdown a session
 306  * @v9ses: session information structure
 307  *
 308  */
 309
 310 void v9fs_session_close(struct v9fs_session_info *v9ses)
 311 {
 312         if (v9ses->clnt) {
 313                 p9_client_destroy(v9ses->clnt);
 314                 v9ses->clnt = NULL;
 315         }
 316
 317 #ifdef CONFIG_9P_FSCACHE
 318         if (v9ses->fscache) {
 319                 v9fs_cache_session_put_cookie(v9ses);
 320                 kfree(v9ses->cachetag);
 321         }
 322 #endif
 323         __putname(v9ses->uname);
 324         __putname(v9ses->aname);
 325
 326         spin_lock(&v9fs_sessionlist_lock);
 327         list_del(&v9ses->slist);
 328         spin_unlock(&v9fs_sessionlist_lock);
 329 }
 330
 331 /**
 332  * v9fs_session_cancel - terminate a session
 333  * @v9ses: session to terminate
 334  *
 335  * mark transport as disconnected and cancel all pending requests.
 336  */
 337
 338 void v9fs_session_cancel(struct v9fs_session_info *v9ses) {
 339         P9_DPRINTK(P9_DEBUG_ERROR, "cancel session %p\n", v9ses);
 340         p9_client_disconnect(v9ses->clnt);
 341 }
 342
 343 extern int v9fs_error_init(void);
 344
 345 static struct kobject *v9fs_kobj;
 346
 347 #ifdef CONFIG_9P_FSCACHE
 348 /**
 349  * caches_show - list caches associated with a session
 350  *
 351  * Returns the size of buffer written.
 352  */
 353
 354 static ssize_t caches_show(struct kobject *kobj,
 355                            struct kobj_attribute *attr,
 356                            char *buf)
 357 {
 358         ssize_t n = 0, count = 0, limit = PAGE_SIZE;
 359         struct v9fs_session_info *v9ses;
 360
 361         spin_lock(&v9fs_sessionlist_lock);
 362         list_for_each_entry(v9ses, &v9fs_sessionlist, slist) {
 363                 if (v9ses->cachetag) {
 364                         n = snprintf(buf, limit, "%s\n", v9ses->cachetag);
 365                         if (n < 0) {
 366                                 count = n;
 367                                 break;
 368                         }
 369
 370                         count += n;
 371                         limit -= n;
 372                 }
 373         }
 374
 375         spin_unlock(&v9fs_sessionlist_lock);
 376         return count;
 377 }
 378
 379 static struct kobj_attribute v9fs_attr_cache = __ATTR_RO(caches);
 380 #endif /* CONFIG_9P_FSCACHE */
 381
 382 static struct attribute *v9fs_attrs[] = {
 383 #ifdef CONFIG_9P_FSCACHE
 384         &v9fs_attr_cache.attr,
 385 #endif
 386         NULL,
 387 };
 388
 389 static struct attribute_group v9fs_attr_group = {
 390         .attrs = v9fs_attrs,
 391 };
 392
 393 /**
 394  * v9fs_sysfs_init - Initialize the v9fs sysfs interface
 395  *
 396  */
 397
 398 static int v9fs_sysfs_init(void)
 399 {
 400         v9fs_kobj = kobject_create_and_add("9p", fs_kobj);
 401         if (!v9fs_kobj)
 402                 return -ENOMEM;
 403
 404         if (sysfs_create_group(v9fs_kobj, &v9fs_attr_group)) {
 405                 kobject_put(v9fs_kobj);
 406                 return -ENOMEM;
 407         }
 408
 409         return 0;
 410 }
 411
 412 /**
 413  * v9fs_sysfs_cleanup - Unregister the v9fs sysfs interface
 414  *
 415  */
 416
 417 static void v9fs_sysfs_cleanup(void)
 418 {
 419         sysfs_remove_group(v9fs_kobj, &v9fs_attr_group);
 420         kobject_put(v9fs_kobj);
 421 }
 422
 423 /**
 424  * init_v9fs - Initialize module
 425  *
 426  */
 427
 428 static int __init init_v9fs(void)
 429 {
 430         int err;
 431         printk(KERN_INFO "Installing v9fs 9p2000 file system support\n");
 432         /* TODO: Setup list of registered trasnport modules */
 433         err = register_filesystem(&v9fs_fs_type);
 434         if (err < 0) {
 435                 printk(KERN_ERR "Failed to register filesystem\n");
 436                 return err;
 437         }
 438
 439         err = v9fs_cache_register();
 440         if (err < 0) {
 441                 printk(KERN_ERR "Failed to register v9fs for caching\n");
 442                 goto out_fs_unreg;
 443         }
 444
 445         err = v9fs_sysfs_init();
 446         if (err < 0) {
 447                 printk(KERN_ERR "Failed to register with sysfs\n");
 448                 goto out_sysfs_cleanup;
 449         }
 450
 451         return 0;
 452
 453 out_sysfs_cleanup:
 454         v9fs_sysfs_cleanup();
 455
 456 out_fs_unreg:
 457         unregister_filesystem(&v9fs_fs_type);
 458
 459         return err;
 460 }
 461
 462 /**
 463  * exit_v9fs - shutdown module
 464  *
 465  */
 466
 467 static void __exit exit_v9fs(void)
 468 {
 469         v9fs_sysfs_cleanup();
 470         v9fs_cache_unregister();
 471         unregister_filesystem(&v9fs_fs_type);
 472 }
 473
 474 module_init(init_v9fs)
 475 module_exit(exit_v9fs)
 476
 477 MODULE_AUTHOR("Latchesar Ionkov <lucho@ionkov.net>");
 478 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
 479 MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
 480 MODULE_LICENSE("GPL");