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         kmem_cache_destroy(afs_inode_cachep);
 127         _leave("");
 128 }
 129
 130 /*
 131  * parse the mount options
 132  * - this function has been shamelessly adapted from the ext3 fs which
 133  *   shamelessly adapted it from the msdos fs
 134  */
 135 static int afs_parse_options(struct afs_mount_params *params,
 136                              char *options, const char **devname)
 137 {
 138         struct afs_cell *cell;
 139         substring_t args[MAX_OPT_ARGS];
 140         char *p;
 141         int token;
 142
 143         _enter("%s", options);
 144
 145         options[PAGE_SIZE - 1] = 0;
 146
 147         while ((p = strsep(&options, ","))) {
 148                 if (!*p)
 149                         continue;
 150
 151                 token = match_token(p, afs_options_list, args);
 152                 switch (token) {
 153                 case afs_opt_cell:
 154                         cell = afs_cell_lookup(args[0].from,
 155                                                args[0].to - args[0].from,
 156                                                false);
 157                         if (IS_ERR(cell))
 158                                 return PTR_ERR(cell);
 159                         afs_put_cell(params->cell);
 160                         params->cell = cell;
 161                         break;
 162
 163                 case afs_opt_rwpath:
 164                         params->rwpath = 1;
 165                         break;
 166
 167                 case afs_opt_vol:
 168                         *devname = args[0].from;
 169                         break;
 170
 171                 case afs_opt_autocell:
 172                         params->autocell = 1;
 173                         break;
 174
 175                 default:
 176                         printk(KERN_ERR "kAFS:"
 177                                " Unknown or invalid mount option: '%s'\n", p);
 178                         return -EINVAL;
 179                 }
 180         }
 181
 182         _leave(" = 0");
 183         return 0;
 184 }
 185
 186 /*
 187  * parse a device name to get cell name, volume name, volume type and R/W
 188  * selector
 189  * - this can be one of the following:
 190  *      "%[cell:]volume[.]"             R/W volume
 191  *      "#[cell:]volume[.]"             R/O or R/W volume (rwpath=0),
 192  *                                       or R/W (rwpath=1) volume
 193  *      "%[cell:]volume.readonly"       R/O volume
 194  *      "#[cell:]volume.readonly"       R/O volume
 195  *      "%[cell:]volume.backup"         Backup volume
 196  *      "#[cell:]volume.backup"         Backup volume
 197  */
 198 static int afs_parse_device_name(struct afs_mount_params *params,
 199                                  const char *name)
 200 {
 201         struct afs_cell *cell;
 202         const char *cellname, *suffix;
 203         int cellnamesz;
 204
 205         _enter(",%s", name);
 206
 207         if (!name) {
 208                 printk(KERN_ERR "kAFS: no volume name specified\n");
 209                 return -EINVAL;
 210         }
 211
 212         if ((name[0] != '%' && name[0] != '#') || !name[1]) {
 213                 printk(KERN_ERR "kAFS: unparsable volume name\n");
 214                 return -EINVAL;
 215         }
 216
 217         /* determine the type of volume we're looking for */
 218         params->type = AFSVL_ROVOL;
 219         params->force = false;
 220         if (params->rwpath || name[0] == '%') {
 221                 params->type = AFSVL_RWVOL;
 222                 params->force = true;
 223         }
 224         name++;
 225
 226         /* split the cell name out if there is one */
 227         params->volname = strchr(name, ':');
 228         if (params->volname) {
 229                 cellname = name;
 230                 cellnamesz = params->volname - name;
 231                 params->volname++;
 232         } else {
 233                 params->volname = name;
 234                 cellname = NULL;
 235                 cellnamesz = 0;
 236         }
 237
 238         /* the volume type is further affected by a possible suffix */
 239         suffix = strrchr(params->volname, '.');
 240         if (suffix) {
 241                 if (strcmp(suffix, ".readonly") == 0) {
 242                         params->type = AFSVL_ROVOL;
 243                         params->force = true;
 244                 } else if (strcmp(suffix, ".backup") == 0) {
 245                         params->type = AFSVL_BACKVOL;
 246                         params->force = true;
 247                 } else if (suffix[1] == 0) {
 248                 } else {
 249                         suffix = NULL;
 250                 }
 251         }
 252
 253         params->volnamesz = suffix ?
 254                 suffix - params->volname : strlen(params->volname);
 255
 256         _debug("cell %*.*s [%p]",
 257                cellnamesz, cellnamesz, cellname ?: "", params->cell);
 258
 259         /* lookup the cell record */
 260         if (cellname || !params->cell) {
 261                 cell = afs_cell_lookup(cellname, cellnamesz, true);
 262                 if (IS_ERR(cell)) {
 263                         printk(KERN_ERR "kAFS: unable to lookup cell '%*.*s'\n",
 264                                cellnamesz, cellnamesz, cellname ?: "");
 265                         return PTR_ERR(cell);
 266                 }
 267                 afs_put_cell(params->cell);
 268                 params->cell = cell;
 269         }
 270
 271         _debug("CELL:%s [%p] VOLUME:%*.*s SUFFIX:%s TYPE:%d%s",
 272                params->cell->name, params->cell,
 273                params->volnamesz, params->volnamesz, params->volname,
 274                suffix ?: "-", params->type, params->force ? " FORCE" : "");
 275
 276         return 0;
 277 }
 278
 279 /*
 280  * check a superblock to see if it's the one we're looking for
 281  */
 282 static int afs_test_super(struct super_block *sb, void *data)
 283 {
 284         struct afs_super_info *as1 = data;
 285         struct afs_super_info *as = sb->s_fs_info;
 286
 287         return as->volume == as1->volume;
 288 }
 289
 290 static int afs_set_super(struct super_block *sb, void *data)
 291 {
 292         sb->s_fs_info = data;
 293         return set_anon_super(sb, NULL);
 294 }
 295
 296 /*
 297  * fill in the superblock
 298  */
 299 static int afs_fill_super(struct super_block *sb,
 300                           struct afs_mount_params *params)
 301 {
 302         struct afs_super_info *as = sb->s_fs_info;
 303         struct afs_fid fid;
 304         struct dentry *root = NULL;
 305         struct inode *inode = NULL;
 306         int ret;
 307
 308         _enter("");
 309
 310         /* fill in the superblock */
 311         sb->s_blocksize         = PAGE_CACHE_SIZE;
 312         sb->s_blocksize_bits    = PAGE_CACHE_SHIFT;
 313         sb->s_magic             = AFS_FS_MAGIC;
 314         sb->s_op                = &afs_super_ops;
 315         sb->s_bdi               = &as->volume->bdi;
 316         strlcpy(sb->s_id, as->volume->vlocation->vldb.name, sizeof(sb->s_id));
 317
 318         /* allocate the root inode and dentry */
 319         fid.vid         = as->volume->vid;
 320         fid.vnode       = 1;
 321         fid.unique      = 1;
 322         inode = afs_iget(sb, params->key, &fid, NULL, NULL);
 323         if (IS_ERR(inode))
 324                 return PTR_ERR(inode);
 325
 326         if (params->autocell)
 327                 set_bit(AFS_VNODE_AUTOCELL, &AFS_FS_I(inode)->flags);
 328
 329         ret = -ENOMEM;
 330         root = d_alloc_root(inode);
 331         if (!root)
 332                 goto error;
 333
 334         sb->s_d_op = &afs_fs_dentry_operations;
 335         sb->s_root = root;
 336
 337         _leave(" = 0");
 338         return 0;
 339
 340 error:
 341         iput(inode);
 342         _leave(" = %d", ret);
 343         return ret;
 344 }
 345
 346 /*
 347  * get an AFS superblock
 348  */
 349 static struct dentry *afs_mount(struct file_system_type *fs_type,
 350                       int flags, const char *dev_name, void *options)
 351 {
 352         struct afs_mount_params params;
 353         struct super_block *sb;
 354         struct afs_volume *vol;
 355         struct key *key;
 356         char *new_opts = kstrdup(options, GFP_KERNEL);
 357         struct afs_super_info *as;
 358         int ret;
 359
 360         _enter(",,%s,%p", dev_name, options);
 361
 362         memset(&params, 0, sizeof(params));
 363
 364         /* parse the options and device name */
 365         if (options) {
 366                 ret = afs_parse_options(&params, options, &dev_name);
 367                 if (ret < 0)
 368                         goto error;
 369         }
 370
 371         ret = afs_parse_device_name(&params, dev_name);
 372         if (ret < 0)
 373                 goto error;
 374
 375         /* try and do the mount securely */
 376         key = afs_request_key(params.cell);
 377         if (IS_ERR(key)) {
 378                 _leave(" = %ld [key]", PTR_ERR(key));
 379                 ret = PTR_ERR(key);
 380                 goto error;
 381         }
 382         params.key = key;
 383
 384         /* parse the device name */
 385         vol = afs_volume_lookup(&params);
 386         if (IS_ERR(vol)) {
 387                 ret = PTR_ERR(vol);
 388                 goto error;
 389         }
 390
 391         /* allocate a superblock info record */
 392         as = kzalloc(sizeof(struct afs_super_info), GFP_KERNEL);
 393         if (!as) {
 394                 ret = -ENOMEM;
 395                 afs_put_volume(vol);
 396                 goto error;
 397         }
 398         as->volume = vol;
 399
 400         /* allocate a deviceless superblock */
 401         sb = sget(fs_type, afs_test_super, afs_set_super, as);
 402         if (IS_ERR(sb)) {
 403                 ret = PTR_ERR(sb);
 404                 afs_put_volume(vol);
 405                 kfree(as);
 406                 goto error;
 407         }
 408
 409         if (!sb->s_root) {
 410                 /* initial superblock/root creation */
 411                 _debug("create");
 412                 sb->s_flags = flags;
 413                 ret = afs_fill_super(sb, &params);
 414                 if (ret < 0) {
 415                         deactivate_locked_super(sb);
 416                         goto error;
 417                 }
 418                 save_mount_options(sb, new_opts);
 419                 sb->s_flags |= MS_ACTIVE;
 420         } else {
 421                 _debug("reuse");
 422                 ASSERTCMP(sb->s_flags, &, MS_ACTIVE);
 423                 afs_put_volume(vol);
 424                 kfree(as);
 425         }
 426
 427         afs_put_cell(params.cell);
 428         kfree(new_opts);
 429         _leave(" = 0 [%p]", sb);
 430         return dget(sb->s_root);
 431
 432 error:
 433         afs_put_cell(params.cell);
 434         key_put(params.key);
 435         kfree(new_opts);
 436         _leave(" = %d", ret);
 437         return ERR_PTR(ret);
 438 }
 439
 440 static void afs_kill_super(struct super_block *sb)
 441 {
 442         struct afs_super_info *as = sb->s_fs_info;
 443         kill_anon_super(sb);
 444         afs_put_volume(as->volume);
 445         kfree(as);
 446 }
 447
 448 /*
 449  * initialise an inode cache slab element prior to any use
 450  */
 451 static void afs_i_init_once(void *_vnode)
 452 {
 453         struct afs_vnode *vnode = _vnode;
 454
 455         memset(vnode, 0, sizeof(*vnode));
 456         inode_init_once(&vnode->vfs_inode);
 457         init_waitqueue_head(&vnode->update_waitq);
 458         mutex_init(&vnode->permits_lock);
 459         mutex_init(&vnode->validate_lock);
 460         spin_lock_init(&vnode->writeback_lock);
 461         spin_lock_init(&vnode->lock);
 462         INIT_LIST_HEAD(&vnode->writebacks);
 463         INIT_LIST_HEAD(&vnode->pending_locks);
 464         INIT_LIST_HEAD(&vnode->granted_locks);
 465         INIT_DELAYED_WORK(&vnode->lock_work, afs_lock_work);
 466         INIT_WORK(&vnode->cb_broken_work, afs_broken_callback_work);
 467 }
 468
 469 /*
 470  * allocate an AFS inode struct from our slab cache
 471  */
 472 static struct inode *afs_alloc_inode(struct super_block *sb)
 473 {
 474         struct afs_vnode *vnode;
 475
 476         vnode = kmem_cache_alloc(afs_inode_cachep, GFP_KERNEL);
 477         if (!vnode)
 478                 return NULL;
 479
 480         atomic_inc(&afs_count_active_inodes);
 481
 482         memset(&vnode->fid, 0, sizeof(vnode->fid));
 483         memset(&vnode->status, 0, sizeof(vnode->status));
 484
 485         vnode->volume           = NULL;
 486         vnode->update_cnt       = 0;
 487         vnode->flags            = 1 << AFS_VNODE_UNSET;
 488         vnode->cb_promised      = false;
 489
 490         _leave(" = %p", &vnode->vfs_inode);
 491         return &vnode->vfs_inode;
 492 }
 493
 494 static void afs_i_callback(struct rcu_head *head)
 495 {
 496         struct inode *inode = container_of(head, struct inode, i_rcu);
 497         struct afs_vnode *vnode = AFS_FS_I(inode);
 498         kmem_cache_free(afs_inode_cachep, vnode);
 499 }
 500
 501 /*
 502  * destroy an AFS inode struct
 503  */
 504 static void afs_destroy_inode(struct inode *inode)
 505 {
 506         struct afs_vnode *vnode = AFS_FS_I(inode);
 507
 508         _enter("%p{%x:%u}", inode, vnode->fid.vid, vnode->fid.vnode);
 509
 510         _debug("DESTROY INODE %p", inode);
 511
 512         ASSERTCMP(vnode->server, ==, NULL);
 513
 514         call_rcu(&inode->i_rcu, afs_i_callback);
 515         atomic_dec(&afs_count_active_inodes);
 516 }
 517
 518 /*
 519  * return information about an AFS volume
 520  */
 521 static int afs_statfs(struct dentry *dentry, struct kstatfs *buf)
 522 {
 523         struct afs_volume_status vs;
 524         struct afs_vnode *vnode = AFS_FS_I(dentry->d_inode);
 525         struct key *key;
 526         int ret;
 527
 528         key = afs_request_key(vnode->volume->cell);
 529         if (IS_ERR(key))
 530                 return PTR_ERR(key);
 531
 532         ret = afs_vnode_get_volume_status(vnode, key, &vs);
 533         key_put(key);
 534         if (ret < 0) {
 535                 _leave(" = %d", ret);
 536                 return ret;
 537         }
 538
 539         buf->f_type     = dentry->d_sb->s_magic;
 540         buf->f_bsize    = AFS_BLOCK_SIZE;
 541         buf->f_namelen  = AFSNAMEMAX - 1;
 542
 543         if (vs.max_quota == 0)
 544                 buf->f_blocks = vs.part_max_blocks;
 545         else
 546                 buf->f_blocks = vs.max_quota;
 547         buf->f_bavail = buf->f_bfree = buf->f_blocks - vs.blocks_in_use;
 548         return 0;
 549 }