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 int afs_get_sb(struct file_system_type *fs_type,
  33                       int flags, const char *dev_name,
  34                       void *data, struct vfsmount *mnt);
  35 static struct inode *afs_alloc_inode(struct super_block *sb);
  36 static void afs_put_super(struct super_block *sb);
  37 static void afs_destroy_inode(struct inode *inode);
  38 static int afs_statfs(struct dentry *dentry, struct kstatfs *buf);
  39
  40 struct file_system_type afs_fs_type = {
  41         .owner          = THIS_MODULE,
  42         .name           = "afs",
  43         .get_sb         = afs_get_sb,
  44         .kill_sb        = kill_anon_super,
  45         .fs_flags       = 0,
  46 };
  47
  48 static const struct super_operations afs_super_ops = {
  49         .statfs         = afs_statfs,
  50         .alloc_inode    = afs_alloc_inode,
  51         .drop_inode     = afs_drop_inode,
  52         .destroy_inode  = afs_destroy_inode,
  53         .evict_inode    = afs_evict_inode,
  54         .put_super      = afs_put_super,
  55         .show_options   = generic_show_options,
  56 };
  57
  58 static struct kmem_cache *afs_inode_cachep;
  59 static atomic_t afs_count_active_inodes;
  60
  61 enum {
  62         afs_no_opt,
  63         afs_opt_cell,
  64         afs_opt_rwpath,
  65         afs_opt_vol,
  66         afs_opt_autocell,
  67 };
  68
  69 static const match_table_t afs_options_list = {
  70         { afs_opt_cell,         "cell=%s"       },
  71         { afs_opt_rwpath,       "rwpath"        },
  72         { afs_opt_vol,          "vol=%s"        },
  73         { afs_opt_autocell,     "autocell"      },
  74         { afs_no_opt,           NULL            },
  75 };
  76
  77 /*
  78  * initialise the filesystem
  79  */
  80 int __init afs_fs_init(void)
  81 {
  82         int ret;
  83
  84         _enter("");
  85
  86         /* create ourselves an inode cache */
  87         atomic_set(&afs_count_active_inodes, 0);
  88
  89         ret = -ENOMEM;
  90         afs_inode_cachep = kmem_cache_create("afs_inode_cache",
  91                                              sizeof(struct afs_vnode),
  92                                              0,
  93                                              SLAB_HWCACHE_ALIGN,
  94                                              afs_i_init_once);
  95         if (!afs_inode_cachep) {
  96                 printk(KERN_NOTICE "kAFS: Failed to allocate inode cache\n");
  97                 return ret;
  98         }
  99
 100         /* now export our filesystem to lesser mortals */
 101         ret = register_filesystem(&afs_fs_type);
 102         if (ret < 0) {
 103                 kmem_cache_destroy(afs_inode_cachep);
 104                 _leave(" = %d", ret);
 105                 return ret;
 106         }
 107
 108         _leave(" = 0");
 109         return 0;
 110 }
 111
 112 /*
 113  * clean up the filesystem
 114  */
 115 void __exit afs_fs_exit(void)
 116 {
 117         _enter("");
 118
 119         afs_mntpt_kill_timer();
 120         unregister_filesystem(&afs_fs_type);
 121
 122         if (atomic_read(&afs_count_active_inodes) != 0) {
 123                 printk("kAFS: %d active inode objects still present\n",
 124                        atomic_read(&afs_count_active_inodes));
 125                 BUG();
 126         }
 127
 128         kmem_cache_destroy(afs_inode_cachep);
 129         _leave("");
 130 }
 131
 132 /*
 133  * parse the mount options
 134  * - this function has been shamelessly adapted from the ext3 fs which
 135  *   shamelessly adapted it from the msdos fs
 136  */
 137 static int afs_parse_options(struct afs_mount_params *params,
 138                              char *options, const char **devname)
 139 {
 140         struct afs_cell *cell;
 141         substring_t args[MAX_OPT_ARGS];
 142         char *p;
 143         int token;
 144
 145         _enter("%s", options);
 146
 147         options[PAGE_SIZE - 1] = 0;
 148
 149         while ((p = strsep(&options, ","))) {
 150                 if (!*p)
 151                         continue;
 152
 153                 token = match_token(p, afs_options_list, args);
 154                 switch (token) {
 155                 case afs_opt_cell:
 156                         cell = afs_cell_lookup(args[0].from,
 157                                                args[0].to - args[0].from,
 158                                                false);
 159                         if (IS_ERR(cell))
 160                                 return PTR_ERR(cell);
 161                         afs_put_cell(params->cell);
 162                         params->cell = cell;
 163                         break;
 164
 165                 case afs_opt_rwpath:
 166                         params->rwpath = 1;
 167                         break;
 168
 169                 case afs_opt_vol:
 170                         *devname = args[0].from;
 171                         break;
 172
 173                 case afs_opt_autocell:
 174                         params->autocell = 1;
 175                         break;
 176
 177                 default:
 178                         printk(KERN_ERR "kAFS:"
 179                                " Unknown or invalid mount option: '%s'\n", p);
 180                         return -EINVAL;
 181                 }
 182         }
 183
 184         _leave(" = 0");
 185         return 0;
 186 }
 187
 188 /*
 189  * parse a device name to get cell name, volume name, volume type and R/W
 190  * selector
 191  * - this can be one of the following:
 192  *      "%[cell:]volume[.]"             R/W volume
 193  *      "#[cell:]volume[.]"             R/O or R/W volume (rwpath=0),
 194  *                                       or R/W (rwpath=1) volume
 195  *      "%[cell:]volume.readonly"       R/O volume
 196  *      "#[cell:]volume.readonly"       R/O volume
 197  *      "%[cell:]volume.backup"         Backup volume
 198  *      "#[cell:]volume.backup"         Backup volume
 199  */
 200 static int afs_parse_device_name(struct afs_mount_params *params,
 201                                  const char *name)
 202 {
 203         struct afs_cell *cell;
 204         const char *cellname, *suffix;
 205         int cellnamesz;
 206
 207         _enter(",%s", name);
 208
 209         if (!name) {
 210                 printk(KERN_ERR "kAFS: no volume name specified\n");
 211                 return -EINVAL;
 212         }
 213
 214         if ((name[0] != '%' && name[0] != '#') || !name[1]) {
 215                 printk(KERN_ERR "kAFS: unparsable volume name\n");
 216                 return -EINVAL;
 217         }
 218
 219         /* determine the type of volume we're looking for */
 220         params->type = AFSVL_ROVOL;
 221         params->force = false;
 222         if (params->rwpath || name[0] == '%') {
 223                 params->type = AFSVL_RWVOL;
 224                 params->force = true;
 225         }
 226         name++;
 227
 228         /* split the cell name out if there is one */
 229         params->volname = strchr(name, ':');
 230         if (params->volname) {
 231                 cellname = name;
 232                 cellnamesz = params->volname - name;
 233                 params->volname++;
 234         } else {
 235                 params->volname = name;
 236                 cellname = NULL;
 237                 cellnamesz = 0;
 238         }
 239
 240         /* the volume type is further affected by a possible suffix */
 241         suffix = strrchr(params->volname, '.');
 242         if (suffix) {
 243                 if (strcmp(suffix, ".readonly") == 0) {
 244                         params->type = AFSVL_ROVOL;
 245                         params->force = true;
 246                 } else if (strcmp(suffix, ".backup") == 0) {
 247                         params->type = AFSVL_BACKVOL;
 248                         params->force = true;
 249                 } else if (suffix[1] == 0) {
 250                 } else {
 251                         suffix = NULL;
 252                 }
 253         }
 254
 255         params->volnamesz = suffix ?
 256                 suffix - params->volname : strlen(params->volname);
 257
 258         _debug("cell %*.*s [%p]",
 259                cellnamesz, cellnamesz, cellname ?: "", params->cell);
 260
 261         /* lookup the cell record */
 262         if (cellname || !params->cell) {
 263                 cell = afs_cell_lookup(cellname, cellnamesz, true);
 264                 if (IS_ERR(cell)) {
 265                         printk(KERN_ERR "kAFS: unable to lookup cell '%*.*s'\n",
 266                                cellnamesz, cellnamesz, cellname ?: "");
 267                         return PTR_ERR(cell);
 268                 }
 269                 afs_put_cell(params->cell);
 270                 params->cell = cell;
 271         }
 272
 273         _debug("CELL:%s [%p] VOLUME:%*.*s SUFFIX:%s TYPE:%d%s",
 274                params->cell->name, params->cell,
 275                params->volnamesz, params->volnamesz, params->volname,
 276                suffix ?: "-", params->type, params->force ? " FORCE" : "");
 277
 278         return 0;
 279 }
 280
 281 /*
 282  * check a superblock to see if it's the one we're looking for
 283  */
 284 static int afs_test_super(struct super_block *sb, void *data)
 285 {
 286         struct afs_mount_params *params = data;
 287         struct afs_super_info *as = sb->s_fs_info;
 288
 289         return as->volume == params->volume;
 290 }
 291
 292 /*
 293  * fill in the superblock
 294  */
 295 static int afs_fill_super(struct super_block *sb, void *data)
 296 {
 297         struct afs_mount_params *params = data;
 298         struct afs_super_info *as = NULL;
 299         struct afs_fid fid;
 300         struct dentry *root = NULL;
 301         struct inode *inode = NULL;
 302         int ret;
 303
 304         _enter("");
 305
 306         /* allocate a superblock info record */
 307         as = kzalloc(sizeof(struct afs_super_info), GFP_KERNEL);
 308         if (!as) {
 309                 _leave(" = -ENOMEM");
 310                 return -ENOMEM;
 311         }
 312
 313         afs_get_volume(params->volume);
 314         as->volume = params->volume;
 315
 316         /* fill in the superblock */
 317         sb->s_blocksize         = PAGE_CACHE_SIZE;
 318         sb->s_blocksize_bits    = PAGE_CACHE_SHIFT;
 319         sb->s_magic             = AFS_FS_MAGIC;
 320         sb->s_op                = &afs_super_ops;
 321         sb->s_fs_info           = as;
 322         sb->s_bdi               = &as->volume->bdi;
 323
 324         /* allocate the root inode and dentry */
 325         fid.vid         = as->volume->vid;
 326         fid.vnode       = 1;
 327         fid.unique      = 1;
 328         inode = afs_iget(sb, params->key, &fid, NULL, NULL);
 329         if (IS_ERR(inode))
 330                 goto error_inode;
 331
 332         if (params->autocell)
 333                 set_bit(AFS_VNODE_AUTOCELL, &AFS_FS_I(inode)->flags);
 334
 335         ret = -ENOMEM;
 336         root = d_alloc_root(inode);
 337         if (!root)
 338                 goto error;
 339
 340         sb->s_root = root;
 341
 342         _leave(" = 0");
 343         return 0;
 344
 345 error_inode:
 346         ret = PTR_ERR(inode);
 347         inode = NULL;
 348 error:
 349         iput(inode);
 350         afs_put_volume(as->volume);
 351         kfree(as);
 352
 353         sb->s_fs_info = NULL;
 354
 355         _leave(" = %d", ret);
 356         return ret;
 357 }
 358
 359 /*
 360  * get an AFS superblock
 361  */
 362 static int afs_get_sb(struct file_system_type *fs_type,
 363                       int flags,
 364                       const char *dev_name,
 365                       void *options,
 366                       struct vfsmount *mnt)
 367 {
 368         struct afs_mount_params params;
 369         struct super_block *sb;
 370         struct afs_volume *vol;
 371         struct key *key;
 372         char *new_opts = kstrdup(options, GFP_KERNEL);
 373         int ret;
 374
 375         _enter(",,%s,%p", dev_name, options);
 376
 377         memset(&params, 0, sizeof(params));
 378
 379         /* parse the options and device name */
 380         if (options) {
 381                 ret = afs_parse_options(&params, options, &dev_name);
 382                 if (ret < 0)
 383                         goto error;
 384         }
 385
 386         ret = afs_parse_device_name(&params, dev_name);
 387         if (ret < 0)
 388                 goto error;
 389
 390         /* try and do the mount securely */
 391         key = afs_request_key(params.cell);
 392         if (IS_ERR(key)) {
 393                 _leave(" = %ld [key]", PTR_ERR(key));
 394                 ret = PTR_ERR(key);
 395                 goto error;
 396         }
 397         params.key = key;
 398
 399         /* parse the device name */
 400         vol = afs_volume_lookup(&params);
 401         if (IS_ERR(vol)) {
 402                 ret = PTR_ERR(vol);
 403                 goto error;
 404         }
 405         params.volume = vol;
 406
 407         /* allocate a deviceless superblock */
 408         sb = sget(fs_type, afs_test_super, set_anon_super, &params);
 409         if (IS_ERR(sb)) {
 410                 ret = PTR_ERR(sb);
 411                 goto error;
 412         }
 413
 414         if (!sb->s_root) {
 415                 /* initial superblock/root creation */
 416                 _debug("create");
 417                 sb->s_flags = flags;
 418                 ret = afs_fill_super(sb, &params);
 419                 if (ret < 0) {
 420                         deactivate_locked_super(sb);
 421                         goto error;
 422                 }
 423                 save_mount_options(sb, new_opts);
 424                 sb->s_flags |= MS_ACTIVE;
 425         } else {
 426                 _debug("reuse");
 427                 ASSERTCMP(sb->s_flags, &, MS_ACTIVE);
 428         }
 429
 430         simple_set_mnt(mnt, sb);
 431         afs_put_volume(params.volume);
 432         afs_put_cell(params.cell);
 433         kfree(new_opts);
 434         _leave(" = 0 [%p]", sb);
 435         return 0;
 436
 437 error:
 438         afs_put_volume(params.volume);
 439         afs_put_cell(params.cell);
 440         key_put(params.key);
 441         kfree(new_opts);
 442         _leave(" = %d", ret);
 443         return ret;
 444 }
 445
 446 /*
 447  * finish the unmounting process on the superblock
 448  */
 449 static void afs_put_super(struct super_block *sb)
 450 {
 451         struct afs_super_info *as = sb->s_fs_info;
 452
 453         _enter("");
 454
 455         afs_put_volume(as->volume);
 456
 457         _leave("");
 458 }
 459
 460 /*
 461  * initialise an inode cache slab element prior to any use
 462  */
 463 static void afs_i_init_once(void *_vnode)
 464 {
 465         struct afs_vnode *vnode = _vnode;
 466
 467         memset(vnode, 0, sizeof(*vnode));
 468         inode_init_once(&vnode->vfs_inode);
 469         init_waitqueue_head(&vnode->update_waitq);
 470         mutex_init(&vnode->permits_lock);
 471         mutex_init(&vnode->validate_lock);
 472         spin_lock_init(&vnode->writeback_lock);
 473         spin_lock_init(&vnode->lock);
 474         INIT_LIST_HEAD(&vnode->writebacks);
 475         INIT_LIST_HEAD(&vnode->pending_locks);
 476         INIT_LIST_HEAD(&vnode->granted_locks);
 477         INIT_DELAYED_WORK(&vnode->lock_work, afs_lock_work);
 478         INIT_WORK(&vnode->cb_broken_work, afs_broken_callback_work);
 479 }
 480
 481 /*
 482  * allocate an AFS inode struct from our slab cache
 483  */
 484 static struct inode *afs_alloc_inode(struct super_block *sb)
 485 {
 486         struct afs_vnode *vnode;
 487
 488         vnode = kmem_cache_alloc(afs_inode_cachep, GFP_KERNEL);
 489         if (!vnode)
 490                 return NULL;
 491
 492         atomic_inc(&afs_count_active_inodes);
 493
 494         memset(&vnode->fid, 0, sizeof(vnode->fid));
 495         memset(&vnode->status, 0, sizeof(vnode->status));
 496
 497         vnode->volume           = NULL;
 498         vnode->update_cnt       = 0;
 499         vnode->flags            = 1 << AFS_VNODE_UNSET;
 500         vnode->cb_promised      = false;
 501
 502         _leave(" = %p", &vnode->vfs_inode);
 503         return &vnode->vfs_inode;
 504 }
 505
 506 /*
 507  * destroy an AFS inode struct
 508  */
 509 static void afs_destroy_inode(struct inode *inode)
 510 {
 511         struct afs_vnode *vnode = AFS_FS_I(inode);
 512
 513         _enter("%p{%x:%u}", inode, vnode->fid.vid, vnode->fid.vnode);
 514
 515         _debug("DESTROY INODE %p", inode);
 516
 517         ASSERTCMP(vnode->server, ==, NULL);
 518
 519         kmem_cache_free(afs_inode_cachep, vnode);
 520         atomic_dec(&afs_count_active_inodes);
 521 }
 522
 523 /*
 524  * return information about an AFS volume
 525  */
 526 static int afs_statfs(struct dentry *dentry, struct kstatfs *buf)
 527 {
 528         struct afs_volume_status vs;
 529         struct afs_vnode *vnode = AFS_FS_I(dentry->d_inode);
 530         struct key *key;
 531         int ret;
 532
 533         key = afs_request_key(vnode->volume->cell);
 534         if (IS_ERR(key))
 535                 return PTR_ERR(key);
 536
 537         ret = afs_vnode_get_volume_status(vnode, key, &vs);
 538         key_put(key);
 539         if (ret < 0) {
 540                 _leave(" = %d", ret);
 541                 return ret;
 542         }
 543
 544         buf->f_type     = dentry->d_sb->s_magic;
 545         buf->f_bsize    = AFS_BLOCK_SIZE;
 546         buf->f_namelen  = AFSNAMEMAX - 1;
 547
 548         if (vs.max_quota == 0)
 549                 buf->f_blocks = vs.part_max_blocks;
 550         else
 551                 buf->f_blocks = vs.max_quota;
 552         buf->f_bavail = buf->f_bfree = buf->f_blocks - vs.blocks_in_use;
 553         return 0;
 554 }