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/smp_lock.h>
  23 #include <linux/fs.h>
  24 #include <linux/pagemap.h>
  25 #include <linux/parser.h>
  26 #include <linux/statfs.h>
  27 #include <linux/sched.h>
  28 #include "internal.h"
  29
  30 #define AFS_FS_MAGIC 0x6B414653 /* 'kAFS' */
  31
  32 static void afs_i_init_once(void *foo);
  33 static int afs_get_sb(struct file_system_type *fs_type,
  34                       int flags, const char *dev_name,
  35                       void *data, struct vfsmount *mnt);
  36 static struct inode *afs_alloc_inode(struct super_block *sb);
  37 static void afs_put_super(struct super_block *sb);
  38 static void afs_destroy_inode(struct inode *inode);
  39 static int afs_statfs(struct dentry *dentry, struct kstatfs *buf);
  40
  41 struct file_system_type afs_fs_type = {
  42         .owner          = THIS_MODULE,
  43         .name           = "afs",
  44         .get_sb         = afs_get_sb,
  45         .kill_sb        = kill_anon_super,
  46         .fs_flags       = 0,
  47 };
  48
  49 static const struct super_operations afs_super_ops = {
  50         .statfs         = afs_statfs,
  51         .alloc_inode    = afs_alloc_inode,
  52         .drop_inode     = afs_drop_inode,
  53         .destroy_inode  = afs_destroy_inode,
  54         .evict_inode    = afs_evict_inode,
  55         .put_super      = afs_put_super,
  56         .show_options   = generic_show_options,
  57 };
  58
  59 static struct kmem_cache *afs_inode_cachep;
  60 static atomic_t afs_count_active_inodes;
  61
  62 enum {
  63         afs_no_opt,
  64         afs_opt_cell,
  65         afs_opt_rwpath,
  66         afs_opt_vol,
  67         afs_opt_autocell,
  68 };
  69
  70 static const match_table_t afs_options_list = {
  71         { afs_opt_cell,         "cell=%s"       },
  72         { afs_opt_rwpath,       "rwpath"        },
  73         { afs_opt_vol,          "vol=%s"        },
  74         { afs_opt_autocell,     "autocell"      },
  75         { afs_no_opt,           NULL            },
  76 };
  77
  78 /*
  79  * initialise the filesystem
  80  */
  81 int __init afs_fs_init(void)
  82 {
  83         int ret;
  84
  85         _enter("");
  86
  87         /* create ourselves an inode cache */
  88         atomic_set(&afs_count_active_inodes, 0);
  89
  90         ret = -ENOMEM;
  91         afs_inode_cachep = kmem_cache_create("afs_inode_cache",
  92                                              sizeof(struct afs_vnode),
  93                                              0,
  94                                              SLAB_HWCACHE_ALIGN,
  95                                              afs_i_init_once);
  96         if (!afs_inode_cachep) {
  97                 printk(KERN_NOTICE "kAFS: Failed to allocate inode cache\n");
  98                 return ret;
  99         }
 100
 101         /* now export our filesystem to lesser mortals */
 102         ret = register_filesystem(&afs_fs_type);
 103         if (ret < 0) {
 104                 kmem_cache_destroy(afs_inode_cachep);
 105                 _leave(" = %d", ret);
 106                 return ret;
 107         }
 108
 109         _leave(" = 0");
 110         return 0;
 111 }
 112
 113 /*
 114  * clean up the filesystem
 115  */
 116 void __exit afs_fs_exit(void)
 117 {
 118         _enter("");
 119
 120         afs_mntpt_kill_timer();
 121         unregister_filesystem(&afs_fs_type);
 122
 123         if (atomic_read(&afs_count_active_inodes) != 0) {
 124                 printk("kAFS: %d active inode objects still present\n",
 125                        atomic_read(&afs_count_active_inodes));
 126                 BUG();
 127         }
 128
 129         kmem_cache_destroy(afs_inode_cachep);
 130         _leave("");
 131 }
 132
 133 /*
 134  * parse the mount options
 135  * - this function has been shamelessly adapted from the ext3 fs which
 136  *   shamelessly adapted it from the msdos fs
 137  */
 138 static int afs_parse_options(struct afs_mount_params *params,
 139                              char *options, const char **devname)
 140 {
 141         struct afs_cell *cell;
 142         substring_t args[MAX_OPT_ARGS];
 143         char *p;
 144         int token;
 145
 146         _enter("%s", options);
 147
 148         options[PAGE_SIZE - 1] = 0;
 149
 150         while ((p = strsep(&options, ","))) {
 151                 if (!*p)
 152                         continue;
 153
 154                 token = match_token(p, afs_options_list, args);
 155                 switch (token) {
 156                 case afs_opt_cell:
 157                         cell = afs_cell_lookup(args[0].from,
 158                                                args[0].to - args[0].from,
 159                                                false);
 160                         if (IS_ERR(cell))
 161                                 return PTR_ERR(cell);
 162                         afs_put_cell(params->cell);
 163                         params->cell = cell;
 164                         break;
 165
 166                 case afs_opt_rwpath:
 167                         params->rwpath = 1;
 168                         break;
 169
 170                 case afs_opt_vol:
 171                         *devname = args[0].from;
 172                         break;
 173
 174                 case afs_opt_autocell:
 175                         params->autocell = 1;
 176                         break;
 177
 178                 default:
 179                         printk(KERN_ERR "kAFS:"
 180                                " Unknown or invalid mount option: '%s'\n", p);
 181                         return -EINVAL;
 182                 }
 183         }
 184
 185         _leave(" = 0");
 186         return 0;
 187 }
 188
 189 /*
 190  * parse a device name to get cell name, volume name, volume type and R/W
 191  * selector
 192  * - this can be one of the following:
 193  *      "%[cell:]volume[.]"             R/W volume
 194  *      "#[cell:]volume[.]"             R/O or R/W volume (rwpath=0),
 195  *                                       or R/W (rwpath=1) volume
 196  *      "%[cell:]volume.readonly"       R/O volume
 197  *      "#[cell:]volume.readonly"       R/O volume
 198  *      "%[cell:]volume.backup"         Backup volume
 199  *      "#[cell:]volume.backup"         Backup volume
 200  */
 201 static int afs_parse_device_name(struct afs_mount_params *params,
 202                                  const char *name)
 203 {
 204         struct afs_cell *cell;
 205         const char *cellname, *suffix;
 206         int cellnamesz;
 207
 208         _enter(",%s", name);
 209
 210         if (!name) {
 211                 printk(KERN_ERR "kAFS: no volume name specified\n");
 212                 return -EINVAL;
 213         }
 214
 215         if ((name[0] != '%' && name[0] != '#') || !name[1]) {
 216                 printk(KERN_ERR "kAFS: unparsable volume name\n");
 217                 return -EINVAL;
 218         }
 219
 220         /* determine the type of volume we're looking for */
 221         params->type = AFSVL_ROVOL;
 222         params->force = false;
 223         if (params->rwpath || name[0] == '%') {
 224                 params->type = AFSVL_RWVOL;
 225                 params->force = true;
 226         }
 227         name++;
 228
 229         /* split the cell name out if there is one */
 230         params->volname = strchr(name, ':');
 231         if (params->volname) {
 232                 cellname = name;
 233                 cellnamesz = params->volname - name;
 234                 params->volname++;
 235         } else {
 236                 params->volname = name;
 237                 cellname = NULL;
 238                 cellnamesz = 0;
 239         }
 240
 241         /* the volume type is further affected by a possible suffix */
 242         suffix = strrchr(params->volname, '.');
 243         if (suffix) {
 244                 if (strcmp(suffix, ".readonly") == 0) {
 245                         params->type = AFSVL_ROVOL;
 246                         params->force = true;
 247                 } else if (strcmp(suffix, ".backup") == 0) {
 248                         params->type = AFSVL_BACKVOL;
 249                         params->force = true;
 250                 } else if (suffix[1] == 0) {
 251                 } else {
 252                         suffix = NULL;
 253                 }
 254         }
 255
 256         params->volnamesz = suffix ?
 257                 suffix - params->volname : strlen(params->volname);
 258
 259         _debug("cell %*.*s [%p]",
 260                cellnamesz, cellnamesz, cellname ?: "", params->cell);
 261
 262         /* lookup the cell record */
 263         if (cellname || !params->cell) {
 264                 cell = afs_cell_lookup(cellname, cellnamesz, true);
 265                 if (IS_ERR(cell)) {
 266                         printk(KERN_ERR "kAFS: unable to lookup cell '%*.*s'\n",
 267                                cellnamesz, cellnamesz, cellname ?: "");
 268                         return PTR_ERR(cell);
 269                 }
 270                 afs_put_cell(params->cell);
 271                 params->cell = cell;
 272         }
 273
 274         _debug("CELL:%s [%p] VOLUME:%*.*s SUFFIX:%s TYPE:%d%s",
 275                params->cell->name, params->cell,
 276                params->volnamesz, params->volnamesz, params->volname,
 277                suffix ?: "-", params->type, params->force ? " FORCE" : "");
 278
 279         return 0;
 280 }
 281
 282 /*
 283  * check a superblock to see if it's the one we're looking for
 284  */
 285 static int afs_test_super(struct super_block *sb, void *data)
 286 {
 287         struct afs_mount_params *params = data;
 288         struct afs_super_info *as = sb->s_fs_info;
 289
 290         return as->volume == params->volume;
 291 }
 292
 293 /*
 294  * fill in the superblock
 295  */
 296 static int afs_fill_super(struct super_block *sb, void *data)
 297 {
 298         struct afs_mount_params *params = data;
 299         struct afs_super_info *as = NULL;
 300         struct afs_fid fid;
 301         struct dentry *root = NULL;
 302         struct inode *inode = NULL;
 303         int ret;
 304
 305         _enter("");
 306
 307         /* allocate a superblock info record */
 308         as = kzalloc(sizeof(struct afs_super_info), GFP_KERNEL);
 309         if (!as) {
 310                 _leave(" = -ENOMEM");
 311                 return -ENOMEM;
 312         }
 313
 314         afs_get_volume(params->volume);
 315         as->volume = params->volume;
 316
 317         /* fill in the superblock */
 318         sb->s_blocksize         = PAGE_CACHE_SIZE;
 319         sb->s_blocksize_bits    = PAGE_CACHE_SHIFT;
 320         sb->s_magic             = AFS_FS_MAGIC;
 321         sb->s_op                = &afs_super_ops;
 322         sb->s_fs_info           = as;
 323         sb->s_bdi               = &as->volume->bdi;
 324
 325         /* allocate the root inode and dentry */
 326         fid.vid         = as->volume->vid;
 327         fid.vnode       = 1;
 328         fid.unique      = 1;
 329         inode = afs_iget(sb, params->key, &fid, NULL, NULL);
 330         if (IS_ERR(inode))
 331                 goto error_inode;
 332
 333         if (params->autocell)
 334                 set_bit(AFS_VNODE_AUTOCELL, &AFS_FS_I(inode)->flags);
 335
 336         ret = -ENOMEM;
 337         root = d_alloc_root(inode);
 338         if (!root)
 339                 goto error;
 340
 341         sb->s_root = root;
 342
 343         _leave(" = 0");
 344         return 0;
 345
 346 error_inode:
 347         ret = PTR_ERR(inode);
 348         inode = NULL;
 349 error:
 350         iput(inode);
 351         afs_put_volume(as->volume);
 352         kfree(as);
 353
 354         sb->s_fs_info = NULL;
 355
 356         _leave(" = %d", ret);
 357         return ret;
 358 }
 359
 360 /*
 361  * get an AFS superblock
 362  */
 363 static int afs_get_sb(struct file_system_type *fs_type,
 364                       int flags,
 365                       const char *dev_name,
 366                       void *options,
 367                       struct vfsmount *mnt)
 368 {
 369         struct afs_mount_params params;
 370         struct super_block *sb;
 371         struct afs_volume *vol;
 372         struct key *key;
 373         char *new_opts = kstrdup(options, GFP_KERNEL);
 374         int ret;
 375
 376         _enter(",,%s,%p", dev_name, options);
 377
 378         memset(&params, 0, sizeof(params));
 379
 380         /* parse the options and device name */
 381         if (options) {
 382                 ret = afs_parse_options(&params, options, &dev_name);
 383                 if (ret < 0)
 384                         goto error;
 385         }
 386
 387         ret = afs_parse_device_name(&params, dev_name);
 388         if (ret < 0)
 389                 goto error;
 390
 391         /* try and do the mount securely */
 392         key = afs_request_key(params.cell);
 393         if (IS_ERR(key)) {
 394                 _leave(" = %ld [key]", PTR_ERR(key));
 395                 ret = PTR_ERR(key);
 396                 goto error;
 397         }
 398         params.key = key;
 399
 400         /* parse the device name */
 401         vol = afs_volume_lookup(&params);
 402         if (IS_ERR(vol)) {
 403                 ret = PTR_ERR(vol);
 404                 goto error;
 405         }
 406         params.volume = vol;
 407
 408         /* allocate a deviceless superblock */
 409         sb = sget(fs_type, afs_test_super, set_anon_super, &params);
 410         if (IS_ERR(sb)) {
 411                 ret = PTR_ERR(sb);
 412                 goto error;
 413         }
 414
 415         if (!sb->s_root) {
 416                 /* initial superblock/root creation */
 417                 _debug("create");
 418                 sb->s_flags = flags;
 419                 ret = afs_fill_super(sb, &params);
 420                 if (ret < 0) {
 421                         deactivate_locked_super(sb);
 422                         goto error;
 423                 }
 424                 save_mount_options(sb, new_opts);
 425                 sb->s_flags |= MS_ACTIVE;
 426         } else {
 427                 _debug("reuse");
 428                 ASSERTCMP(sb->s_flags, &, MS_ACTIVE);
 429         }
 430
 431         simple_set_mnt(mnt, sb);
 432         afs_put_volume(params.volume);
 433         afs_put_cell(params.cell);
 434         kfree(new_opts);
 435         _leave(" = 0 [%p]", sb);
 436         return 0;
 437
 438 error:
 439         afs_put_volume(params.volume);
 440         afs_put_cell(params.cell);
 441         key_put(params.key);
 442         kfree(new_opts);
 443         _leave(" = %d", ret);
 444         return ret;
 445 }
 446
 447 /*
 448  * finish the unmounting process on the superblock
 449  */
 450 static void afs_put_super(struct super_block *sb)
 451 {
 452         struct afs_super_info *as = sb->s_fs_info;
 453
 454         _enter("");
 455
 456         lock_kernel();
 457
 458         afs_put_volume(as->volume);
 459
 460         unlock_kernel();
 461
 462         _leave("");
 463 }
 464
 465 /*
 466  * initialise an inode cache slab element prior to any use
 467  */
 468 static void afs_i_init_once(void *_vnode)
 469 {
 470         struct afs_vnode *vnode = _vnode;
 471
 472         memset(vnode, 0, sizeof(*vnode));
 473         inode_init_once(&vnode->vfs_inode);
 474         init_waitqueue_head(&vnode->update_waitq);
 475         mutex_init(&vnode->permits_lock);
 476         mutex_init(&vnode->validate_lock);
 477         spin_lock_init(&vnode->writeback_lock);
 478         spin_lock_init(&vnode->lock);
 479         INIT_LIST_HEAD(&vnode->writebacks);
 480         INIT_LIST_HEAD(&vnode->pending_locks);
 481         INIT_LIST_HEAD(&vnode->granted_locks);
 482         INIT_DELAYED_WORK(&vnode->lock_work, afs_lock_work);
 483         INIT_WORK(&vnode->cb_broken_work, afs_broken_callback_work);
 484 }
 485
 486 /*
 487  * allocate an AFS inode struct from our slab cache
 488  */
 489 static struct inode *afs_alloc_inode(struct super_block *sb)
 490 {
 491         struct afs_vnode *vnode;
 492
 493         vnode = kmem_cache_alloc(afs_inode_cachep, GFP_KERNEL);
 494         if (!vnode)
 495                 return NULL;
 496
 497         atomic_inc(&afs_count_active_inodes);
 498
 499         memset(&vnode->fid, 0, sizeof(vnode->fid));
 500         memset(&vnode->status, 0, sizeof(vnode->status));
 501
 502         vnode->volume           = NULL;
 503         vnode->update_cnt       = 0;
 504         vnode->flags            = 1 << AFS_VNODE_UNSET;
 505         vnode->cb_promised      = false;
 506
 507         _leave(" = %p", &vnode->vfs_inode);
 508         return &vnode->vfs_inode;
 509 }
 510
 511 /*
 512  * destroy an AFS inode struct
 513  */
 514 static void afs_destroy_inode(struct inode *inode)
 515 {
 516         struct afs_vnode *vnode = AFS_FS_I(inode);
 517
 518         _enter("%p{%x:%u}", inode, vnode->fid.vid, vnode->fid.vnode);
 519
 520         _debug("DESTROY INODE %p", inode);
 521
 522         ASSERTCMP(vnode->server, ==, NULL);
 523
 524         kmem_cache_free(afs_inode_cachep, vnode);
 525         atomic_dec(&afs_count_active_inodes);
 526 }
 527
 528 /*
 529  * return information about an AFS volume
 530  */
 531 static int afs_statfs(struct dentry *dentry, struct kstatfs *buf)
 532 {
 533         struct afs_volume_status vs;
 534         struct afs_vnode *vnode = AFS_FS_I(dentry->d_inode);
 535         struct key *key;
 536         int ret;
 537
 538         key = afs_request_key(vnode->volume->cell);
 539         if (IS_ERR(key))
 540                 return PTR_ERR(key);
 541
 542         ret = afs_vnode_get_volume_status(vnode, key, &vs);
 543         key_put(key);
 544         if (ret < 0) {
 545                 _leave(" = %d", ret);
 546                 return ret;
 547         }
 548
 549         buf->f_type     = dentry->d_sb->s_magic;
 550         buf->f_bsize    = AFS_BLOCK_SIZE;
 551         buf->f_namelen  = AFSNAMEMAX - 1;
 552
 553         if (vs.max_quota == 0)
 554                 buf->f_blocks = vs.part_max_blocks;
 555         else
 556                 buf->f_blocks = vs.max_quota;
 557         buf->f_bavail = buf->f_bfree = buf->f_blocks - vs.blocks_in_use;
 558         return 0;
 559 }