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