fs/afs/super.c

   1 /* AFS superblock handling
   2  *
   3  * Copyright (c) 2002, 2007 Red Hat, Inc. All rights reserved.
   4  *
   5  * This software may be freely redistributed under the terms of the
   6  * GNU General Public License.
   7  *
   8  * You should have received a copy of the GNU General Public License
   9  * along with this program; if not, write to the Free Software
  10  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  11  *
  12  * Authors: David Howells <dhowells@redhat.com>
  13  *          David Woodhouse <dwmw2@infradead.org>
  14  *
  15  */
  16
  17 #include <linux/kernel.h>
  18 #include <linux/module.h>
  19 #include <linux/mount.h>
  20 #include <linux/init.h>
  21 #include <linux/slab.h>
  22 #include <linux/fs.h>
  23 #include <linux/pagemap.h>
  24 #include <linux/parser.h>
  25 #include <linux/statfs.h>
  26 #include <linux/sched.h>
  27 #include "internal.h"
  28
  29 #define AFS_FS_MAGIC 0x6B414653 /* 'kAFS' */
  30
  31 static void afs_i_init_once(void *foo);
  32 static struct dentry *afs_mount(struct file_system_type *fs_type,
  33                       int flags, const char *dev_name, void *data);
  34 static void afs_kill_super(struct super_block *sb);
  35 static struct inode *afs_alloc_inode(struct super_block *sb);
  36 static void afs_destroy_inode(struct inode *inode);
  37 static int afs_statfs(struct dentry *dentry, struct kstatfs *buf);
  38
  39 struct file_system_type afs_fs_type = {
  40         .owner          = THIS_MODULE,
  41         .name           = "afs",
  42         .mount          = afs_mount,
  43         .kill_sb        = afs_kill_super,
  44         .fs_flags       = 0,
  45 };
  46
  47 static const struct super_operations afs_super_ops = {
  48         .statfs         = afs_statfs,
  49         .alloc_inode    = afs_alloc_inode,
  50         .drop_inode     = afs_drop_inode,
  51         .destroy_inode  = afs_destroy_inode,
  52         .evict_inode    = afs_evict_inode,
  53         .show_options   = generic_show_options,
  54 };
  55
  56 static struct kmem_cache *afs_inode_cachep;
  57 static atomic_t afs_count_active_inodes;
  58
  59 enum {
  60         afs_no_opt,
  61         afs_opt_cell,
  62         afs_opt_rwpath,
  63         afs_opt_vol,
  64         afs_opt_autocell,
  65 };
  66
  67 static const match_table_t afs_options_list = {
  68         { afs_opt_cell,         "cell=%s"       },
  69         { afs_opt_rwpath,       "rwpath"        },
  70         { afs_opt_vol,          "vol=%s"        },
  71         { afs_opt_autocell,     "autocell"      },
  72         { afs_no_opt,           NULL            },
  73 };
  74
  75 /*
  76  * initialise the filesystem
  77  */
  78 int __init afs_fs_init(void)
  79 {
  80         int ret;
  81
  82         _enter("");
  83
  84         /* create ourselves an inode cache */
  85         atomic_set(&afs_count_active_inodes, 0);
  86
  87         ret = -ENOMEM;
  88         afs_inode_cachep = kmem_cache_create("afs_inode_cache",
  89                                              sizeof(struct afs_vnode),
  90                                              0,
  91                                              SLAB_HWCACHE_ALIGN,
  92                                              afs_i_init_once);
  93         if (!afs_inode_cachep) {
  94                 printk(KERN_NOTICE "kAFS: Failed to allocate inode cache\n");
  95                 return ret;
  96         }
  97
  98         /* now export our filesystem to lesser mortals */
  99         ret = register_filesystem(&afs_fs_type);
 100         if (ret < 0) {
 101                 kmem_cache_destroy(afs_inode_cachep);
 102                 _leave(" = %d", ret);
 103                 return ret;
 104         }
 105
 106         _leave(" = 0");
 107         return 0;
 108 }
 109
 110 /*
 111  * clean up the filesystem
 112  */
 113 void __exit afs_fs_exit(void)
 114 {
 115         _enter("");
 116
 117         afs_mntpt_kill_timer();
 118         unregister_filesystem(&afs_fs_type);
 119
 120         if (atomic_read(&afs_count_active_inodes) != 0) {
 121                 printk("kAFS: %d active inode objects still present\n",
 122                        atomic_read(&afs_count_active_inodes));
 123                 BUG();
 124         }
 125
 126         /*
 127          * Make sure all delayed rcu free inodes are flushed before we
 128          * destroy cache.
 129          */
 130         rcu_barrier();
 131         kmem_cache_destroy(afs_inode_cachep);
 132         _leave("");
 133 }
 134
 135 /*
 136  * parse the mount options
 137  * - this function has been shamelessly adapted from the ext3 fs which
 138  *   shamelessly adapted it from the msdos fs
 139  */
 140 static int afs_parse_options(struct afs_mount_params *params,
 141                              char *options, const char **devname)
 142 {
 143         struct afs_cell *cell;
 144         substring_t args[MAX_OPT_ARGS];
 145         char *p;
 146         int token;
 147
 148         _enter("%s", options);
 149
 150         options[PAGE_SIZE - 1] = 0;
 151
 152         while ((p = strsep(&options, ","))) {
 153                 if (!*p)
 154                         continue;
 155
 156                 token = match_token(p, afs_options_list, args);
 157                 switch (token) {
 158                 case afs_opt_cell:
 159                         cell = afs_cell_lookup(args[0].from,
 160                                                args[0].to - args[0].from,
 161                                                false);
 162                         if (IS_ERR(cell))
 163                                 return PTR_ERR(cell);
 164                         afs_put_cell(params->cell);
 165                         params->cell = cell;
 166                         break;
 167
 168                 case afs_opt_rwpath:
 169                         params->rwpath = 1;
 170                         break;
 171
 172                 case afs_opt_vol:
 173                         *devname = args[0].from;
 174                         break;
 175
 176                 case afs_opt_autocell:
 177                         params->autocell = 1;
 178                         break;
 179
 180                 default:
 181                         printk(KERN_ERR "kAFS:"
 182                                " Unknown or invalid mount option: '%s'\n", p);
 183                         return -EINVAL;
 184                 }
 185         }
 186
 187         _leave(" = 0");
 188         return 0;
 189 }
 190
 191 /*
 192  * parse a device name to get cell name, volume name, volume type and R/W
 193  * selector
 194  * - this can be one of the following:
 195  *      "%[cell:]volume[.]"             R/W volume
 196  *      "#[cell:]volume[.]"             R/O or R/W volume (rwpath=0),
 197  *                                       or R/W (rwpath=1) volume
 198  *      "%[cell:]volume.readonly"       R/O volume
 199  *      "#[cell:]volume.readonly"       R/O volume
 200  *      "%[cell:]volume.backup"         Backup volume
 201  *      "#[cell:]volume.backup"         Backup volume
 202  */
 203 static int afs_parse_device_name(struct afs_mount_params *params,
 204                                  const char *name)
 205 {
 206         struct afs_cell *cell;
 207         const char *cellname, *suffix;
 208         int cellnamesz;
 209
 210         _enter(",%s", name);
 211
 212         if (!name) {
 213                 printk(KERN_ERR "kAFS: no volume name specified\n");
 214                 return -EINVAL;
 215         }
 216
 217         if ((name[0] != '%' && name[0] != '#') || !name[1]) {
 218                 printk(KERN_ERR "kAFS: unparsable volume name\n");
 219                 return -EINVAL;
 220         }
 221
 222         /* determine the type of volume we're looking for */
 223         params->type = AFSVL_ROVOL;
 224         params->force = false;
 225         if (params->rwpath || name[0] == '%') {
 226                 params->type = AFSVL_RWVOL;
 227                 params->force = true;
 228         }
 229         name++;
 230
 231         /* split the cell name out if there is one */
 232         params->volname = strchr(name, ':');
 233         if (params->volname) {
 234                 cellname = name;
 235                 cellnamesz = params->volname - name;
 236                 params->volname++;
 237         } else {
 238                 params->volname = name;
 239                 cellname = NULL;
 240                 cellnamesz = 0;
 241         }
 242
 243         /* the volume type is further affected by a possible suffix */
 244         suffix = strrchr(params->volname, '.');
 245         if (suffix) {
 246                 if (strcmp(suffix, ".readonly") == 0) {
 247                         params->type = AFSVL_ROVOL;
 248                         params->force = true;
 249                 } else if (strcmp(suffix, ".backup") == 0) {
 250                         params->type = AFSVL_BACKVOL;
 251                         params->force = true;
 252                 } else if (suffix[1] == 0) {
 253                 } else {
 254                         suffix = NULL;
 255                 }
 256         }
 257
 258         params->volnamesz = suffix ?
 259                 suffix - params->volname : strlen(params->volname);
 260
 261         _debug("cell %*.*s [%p]",
 262                cellnamesz, cellnamesz, cellname ?: "", params->cell);
 263
 264         /* lookup the cell record */
 265         if (cellname || !params->cell) {
 266                 cell = afs_cell_lookup(cellname, cellnamesz, true);
 267                 if (IS_ERR(cell)) {
 268                         printk(KERN_ERR "kAFS: unable to lookup cell '%*.*s'\n",
 269                                cellnamesz, cellnamesz, cellname ?: "");
 270                         return PTR_ERR(cell);
 271                 }
 272                 afs_put_cell(params->cell);
 273                 params->cell = cell;
 274         }
 275
 276         _debug("CELL:%s [%p] VOLUME:%*.*s SUFFIX:%s TYPE:%d%s",
 277                params->cell->name, params->cell,
 278                params->volnamesz, params->volnamesz, params->volname,
 279                suffix ?: "-", params->type, params->force ? " FORCE" : "");
 280
 281         return 0;
 282 }
 283
 284 /*
 285  * check a superblock to see if it's the one we're looking for
 286  */
 287 static int afs_test_super(struct super_block *sb, void *data)
 288 {
 289         struct afs_super_info *as1 = data;
 290         struct afs_super_info *as = sb->s_fs_info;
 291
 292         return as->volume == as1->volume;
 293 }
 294
 295 static int afs_set_super(struct super_block *sb, void *data)
 296 {
 297         sb->s_fs_info = data;
 298         return set_anon_super(sb, NULL);
 299 }
 300
 301 /*
 302  * fill in the superblock
 303  */
 304 static int afs_fill_super(struct super_block *sb,
 305                           struct afs_mount_params *params)
 306 {
 307         struct afs_super_info *as = sb->s_fs_info;
 308         struct afs_fid fid;
 309         struct inode *inode = NULL;
 310         int ret;
 311
 312         _enter("");
 313
 314         /* fill in the superblock */
 315         sb->s_blocksize         = PAGE_CACHE_SIZE;
 316         sb->s_blocksize_bits    = PAGE_CACHE_SHIFT;
 317         sb->s_magic             = AFS_FS_MAGIC;
 318         sb->s_op                = &afs_super_ops;
 319         sb->s_bdi               = &as->volume->bdi;
 320         strlcpy(sb->s_id, as->volume->vlocation->vldb.name, sizeof(sb->s_id));
 321
 322         /* allocate the root inode and dentry */
 323         fid.vid         = as->volume->vid;
 324         fid.vnode       = 1;
 325         fid.unique      = 1;
 326         inode = afs_iget(sb, params->key, &fid, NULL, NULL);
 327         if (IS_ERR(inode))
 328                 return PTR_ERR(inode);
 329
 330         if (params->autocell)
 331                 set_bit(AFS_VNODE_AUTOCELL, &AFS_FS_I(inode)->flags);
 332
 333         ret = -ENOMEM;
 334         sb->s_root = d_make_root(inode);
 335         if (!sb->s_root)
 336                 goto error;
 337
 338         sb->s_d_op = &afs_fs_dentry_operations;
 339
 340         _leave(" = 0");
 341         return 0;
 342
 343 error:
 344         _leave(" = %d", ret);
 345         return ret;
 346 }
 347
 348 /*
 349  * get an AFS superblock
 350  */
 351 static struct dentry *afs_mount(struct file_system_type *fs_type,
 352                       int flags, const char *dev_name, void *options)
 353 {
 354         struct afs_mount_params params;
 355         struct super_block *sb;
 356         struct afs_volume *vol;
 357         struct key *key;
 358         char *new_opts = kstrdup(options, GFP_KERNEL);
 359         struct afs_super_info *as;
 360         int ret;
 361
 362         _enter(",,%s,%p", dev_name, options);
 363
 364         memset(&params, 0, sizeof(params));
 365
 366         /* parse the options and device name */
 367         if (options) {
 368                 ret = afs_parse_options(&params, options, &dev_name);
 369                 if (ret < 0)
 370                         goto error;
 371         }
 372
 373         ret = afs_parse_device_name(&params, dev_name);
 374         if (ret < 0)
 375                 goto error;
 376
 377         /* try and do the mount securely */
 378         key = afs_request_key(params.cell);
 379         if (IS_ERR(key)) {
 380                 _leave(" = %ld [key]", PTR_ERR(key));
 381                 ret = PTR_ERR(key);
 382                 goto error;
 383         }
 384         params.key = key;
 385
 386         /* parse the device name */
 387         vol = afs_volume_lookup(&params);
 388         if (IS_ERR(vol)) {
 389                 ret = PTR_ERR(vol);
 390                 goto error;
 391         }
 392
 393         /* allocate a superblock info record */
 394         as = kzalloc(sizeof(struct afs_super_info), GFP_KERNEL);
 395         if (!as) {
 396                 ret = -ENOMEM;
 397                 afs_put_volume(vol);
 398                 goto error;
 399         }
 400         as->volume = vol;
 401
 402         /* allocate a deviceless superblock */
 403         sb = sget(fs_type, afs_test_super, afs_set_super, flags, as);
 404         if (IS_ERR(sb)) {
 405                 ret = PTR_ERR(sb);
 406                 afs_put_volume(vol);
 407                 kfree(as);
 408                 goto error;
 409         }
 410
 411         if (!sb->s_root) {
 412                 /* initial superblock/root creation */
 413                 _debug("create");
 414                 ret = afs_fill_super(sb, &params);
 415                 if (ret < 0) {
 416                         deactivate_locked_super(sb);
 417                         goto error;
 418                 }
 419                 save_mount_options(sb, new_opts);
 420                 sb->s_flags |= MS_ACTIVE;
 421         } else {
 422                 _debug("reuse");
 423                 ASSERTCMP(sb->s_flags, &, MS_ACTIVE);
 424                 afs_put_volume(vol);
 425                 kfree(as);
 426         }
 427
 428         afs_put_cell(params.cell);
 429         kfree(new_opts);
 430         _leave(" = 0 [%p]", sb);
 431         return dget(sb->s_root);
 432
 433 error:
 434         afs_put_cell(params.cell);
 435         key_put(params.key);
 436         kfree(new_opts);
 437         _leave(" = %d", ret);
 438         return ERR_PTR(ret);
 439 }
 440
 441 static void afs_kill_super(struct super_block *sb)
 442 {
 443         struct afs_super_info *as = sb->s_fs_info;
 444         kill_anon_super(sb);
 445         afs_put_volume(as->volume);
 446         kfree(as);
 447 }
 448
 449 /*
 450  * initialise an inode cache slab element prior to any use
 451  */
 452 static void afs_i_init_once(void *_vnode)
 453 {
 454         struct afs_vnode *vnode = _vnode;
 455
 456         memset(vnode, 0, sizeof(*vnode));
 457         inode_init_once(&vnode->vfs_inode);
 458         init_waitqueue_head(&vnode->update_waitq);
 459         mutex_init(&vnode->permits_lock);
 460         mutex_init(&vnode->validate_lock);
 461         spin_lock_init(&vnode->writeback_lock);
 462         spin_lock_init(&vnode->lock);
 463         INIT_LIST_HEAD(&vnode->writebacks);
 464         INIT_LIST_HEAD(&vnode->pending_locks);
 465         INIT_LIST_HEAD(&vnode->granted_locks);
 466         INIT_DELAYED_WORK(&vnode->lock_work, afs_lock_work);
 467         INIT_WORK(&vnode->cb_broken_work, afs_broken_callback_work);
 468 }
 469
 470 /*
 471  * allocate an AFS inode struct from our slab cache
 472  */
 473 static struct inode *afs_alloc_inode(struct super_block *sb)
 474 {
 475         struct afs_vnode *vnode;
 476
 477         vnode = kmem_cache_alloc(afs_inode_cachep, GFP_KERNEL);
 478         if (!vnode)
 479                 return NULL;
 480
 481         atomic_inc(&afs_count_active_inodes);
 482
 483         memset(&vnode->fid, 0, sizeof(vnode->fid));
 484         memset(&vnode->status, 0, sizeof(vnode->status));
 485
 486         vnode->volume           = NULL;
 487         vnode->update_cnt       = 0;
 488         vnode->flags            = 1 << AFS_VNODE_UNSET;
 489         vnode->cb_promised      = false;
 490
 491         _leave(" = %p", &vnode->vfs_inode);
 492         return &vnode->vfs_inode;
 493 }
 494
 495 static void afs_i_callback(struct rcu_head *head)
 496 {
 497         struct inode *inode = container_of(head, struct inode, i_rcu);
 498         struct afs_vnode *vnode = AFS_FS_I(inode);
 499         kmem_cache_free(afs_inode_cachep, vnode);
 500 }
 501
 502 /*
 503  * destroy an AFS inode struct
 504  */
 505 static void afs_destroy_inode(struct inode *inode)
 506 {
 507         struct afs_vnode *vnode = AFS_FS_I(inode);
 508
 509         _enter("%p{%x:%u}", inode, vnode->fid.vid, vnode->fid.vnode);
 510
 511         _debug("DESTROY INODE %p", inode);
 512
 513         ASSERTCMP(vnode->server, ==, NULL);
 514
 515         call_rcu(&inode->i_rcu, afs_i_callback);
 516         atomic_dec(&afs_count_active_inodes);
 517 }
 518
 519 /*
 520  * return information about an AFS volume
 521  */
 522 static int afs_statfs(struct dentry *dentry, struct kstatfs *buf)
 523 {
 524         struct afs_volume_status vs;
 525         struct afs_vnode *vnode = AFS_FS_I(dentry->d_inode);
 526         struct key *key;
 527         int ret;
 528
 529         key = afs_request_key(vnode->volume->cell);
 530         if (IS_ERR(key))
 531                 return PTR_ERR(key);
 532
 533         ret = afs_vnode_get_volume_status(vnode, key, &vs);
 534         key_put(key);
 535         if (ret < 0) {
 536                 _leave(" = %d", ret);
 537                 return ret;
 538         }
 539
 540         buf->f_type     = dentry->d_sb->s_magic;
 541         buf->f_bsize    = AFS_BLOCK_SIZE;
 542         buf->f_namelen  = AFSNAMEMAX - 1;
 543
 544         if (vs.max_quota == 0)
 545                 buf->f_blocks = vs.part_max_blocks;
 546         else
 547                 buf->f_blocks = vs.max_quota;
 548         buf->f_bavail = buf->f_bfree = buf->f_blocks - vs.blocks_in_use;
 549         return 0;
 550 }