release/src-rt-6.x/linux/linux-2.6/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@redhat.com>
  14  *
  15  */
  16
  17 #include <linux/kernel.h>
  18 #include <linux/module.h>
  19 #include <linux/init.h>
  20 #include <linux/slab.h>
  21 #include <linux/fs.h>
  22 #include <linux/pagemap.h>
  23 #include <linux/parser.h>
  24 #include <linux/statfs.h>
  25 #include <linux/sched.h>
  26 #include "internal.h"
  27
  28 #define AFS_FS_MAGIC 0x6B414653 /* 'kAFS' */
  29
  30 static void afs_i_init_once(void *foo, struct kmem_cache *cachep,
  31                             unsigned long flags);
  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         .write_inode    = afs_write_inode,
  52         .destroy_inode  = afs_destroy_inode,
  53         .clear_inode    = afs_clear_inode,
  54         .umount_begin   = afs_umount_begin,
  55         .put_super      = afs_put_super,
  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 };
  67
  68 static match_table_t afs_options_list = {
  69         { afs_opt_cell,         "cell=%s"       },
  70         { afs_opt_rwpath,       "rwpath"        },
  71         { afs_opt_vol,          "vol=%s"        },
  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                                              NULL);
  94         if (!afs_inode_cachep) {
  95                 printk(KERN_NOTICE "kAFS: Failed to allocate inode cache\n");
  96                 return ret;
  97         }
  98
  99         /* now export our filesystem to lesser mortals */
 100         ret = register_filesystem(&afs_fs_type);
 101         if (ret < 0) {
 102                 kmem_cache_destroy(afs_inode_cachep);
 103                 _leave(" = %d", ret);
 104                 return ret;
 105         }
 106
 107         _leave(" = 0");
 108         return 0;
 109 }
 110
 111 /*
 112  * clean up the filesystem
 113  */
 114 void __exit afs_fs_exit(void)
 115 {
 116         _enter("");
 117
 118         afs_mntpt_kill_timer();
 119         unregister_filesystem(&afs_fs_type);
 120
 121         if (atomic_read(&afs_count_active_inodes) != 0) {
 122                 printk("kAFS: %d active inode objects still present\n",
 123                        atomic_read(&afs_count_active_inodes));
 124                 BUG();
 125         }
 126
 127         kmem_cache_destroy(afs_inode_cachep);
 128         _leave("");
 129 }
 130
 131 /*
 132  * parse the mount options
 133  * - this function has been shamelessly adapted from the ext3 fs which
 134  *   shamelessly adapted it from the msdos fs
 135  */
 136 static int afs_parse_options(struct afs_mount_params *params,
 137                              char *options, const char **devname)
 138 {
 139         struct afs_cell *cell;
 140         substring_t args[MAX_OPT_ARGS];
 141         char *p;
 142         int token;
 143
 144         _enter("%s", options);
 145
 146         options[PAGE_SIZE - 1] = 0;
 147
 148         while ((p = strsep(&options, ","))) {
 149                 if (!*p)
 150                         continue;
 151
 152                 token = match_token(p, afs_options_list, args);
 153                 switch (token) {
 154                 case afs_opt_cell:
 155                         cell = afs_cell_lookup(args[0].from,
 156                                                args[0].to - args[0].from);
 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                 default:
 172                         printk(KERN_ERR "kAFS:"
 173                                " Unknown or invalid mount option: '%s'\n", p);
 174                         return -EINVAL;
 175                 }
 176         }
 177
 178         _leave(" = 0");
 179         return 0;
 180 }
 181
 182 /*
 183  * parse a device name to get cell name, volume name, volume type and R/W
 184  * selector
 185  * - this can be one of the following:
 186  *      "%[cell:]volume[.]"             R/W volume
 187  *      "#[cell:]volume[.]"             R/O or R/W volume (rwpath=0),
 188  *                                       or R/W (rwpath=1) volume
 189  *      "%[cell:]volume.readonly"       R/O volume
 190  *      "#[cell:]volume.readonly"       R/O volume
 191  *      "%[cell:]volume.backup"         Backup volume
 192  *      "#[cell:]volume.backup"         Backup volume
 193  */
 194 static int afs_parse_device_name(struct afs_mount_params *params,
 195                                  const char *name)
 196 {
 197         struct afs_cell *cell;
 198         const char *cellname, *suffix;
 199         int cellnamesz;
 200
 201         _enter(",%s", name);
 202
 203         if (!name) {
 204                 printk(KERN_ERR "kAFS: no volume name specified\n");
 205                 return -EINVAL;
 206         }
 207
 208         if ((name[0] != '%' && name[0] != '#') || !name[1]) {
 209                 printk(KERN_ERR "kAFS: unparsable volume name\n");
 210                 return -EINVAL;
 211         }
 212
 213         /* determine the type of volume we're looking for */
 214         params->type = AFSVL_ROVOL;
 215         params->force = false;
 216         if (params->rwpath || name[0] == '%') {
 217                 params->type = AFSVL_RWVOL;
 218                 params->force = true;
 219         }
 220         name++;
 221
 222         /* split the cell name out if there is one */
 223         params->volname = strchr(name, ':');
 224         if (params->volname) {
 225                 cellname = name;
 226                 cellnamesz = params->volname - name;
 227                 params->volname++;
 228         } else {
 229                 params->volname = name;
 230                 cellname = NULL;
 231                 cellnamesz = 0;
 232         }
 233
 234         /* the volume type is further affected by a possible suffix */
 235         suffix = strrchr(params->volname, '.');
 236         if (suffix) {
 237                 if (strcmp(suffix, ".readonly") == 0) {
 238                         params->type = AFSVL_ROVOL;
 239                         params->force = true;
 240                 } else if (strcmp(suffix, ".backup") == 0) {
 241                         params->type = AFSVL_BACKVOL;
 242                         params->force = true;
 243                 } else if (suffix[1] == 0) {
 244                 } else {
 245                         suffix = NULL;
 246                 }
 247         }
 248
 249         params->volnamesz = suffix ?
 250                 suffix - params->volname : strlen(params->volname);
 251
 252         _debug("cell %*.*s [%p]",
 253                cellnamesz, cellnamesz, cellname ?: "", params->cell);
 254
 255         /* lookup the cell record */
 256         if (cellname || !params->cell) {
 257                 cell = afs_cell_lookup(cellname, cellnamesz);
 258                 if (IS_ERR(cell)) {
 259                         printk(KERN_ERR "kAFS: unable to lookup cell '%s'\n",
 260                                cellname ?: "");
 261                         return PTR_ERR(cell);
 262                 }
 263                 afs_put_cell(params->cell);
 264                 params->cell = cell;
 265         }
 266
 267         _debug("CELL:%s [%p] VOLUME:%*.*s SUFFIX:%s TYPE:%d%s",
 268                params->cell->name, params->cell,
 269                params->volnamesz, params->volnamesz, params->volname,
 270                suffix ?: "-", params->type, params->force ? " FORCE" : "");
 271
 272         return 0;
 273 }
 274
 275 /*
 276  * check a superblock to see if it's the one we're looking for
 277  */
 278 static int afs_test_super(struct super_block *sb, void *data)
 279 {
 280         struct afs_mount_params *params = data;
 281         struct afs_super_info *as = sb->s_fs_info;
 282
 283         return as->volume == params->volume;
 284 }
 285
 286 /*
 287  * fill in the superblock
 288  */
 289 static int afs_fill_super(struct super_block *sb, void *data)
 290 {
 291         struct afs_mount_params *params = data;
 292         struct afs_super_info *as = NULL;
 293         struct afs_fid fid;
 294         struct dentry *root = NULL;
 295         struct inode *inode = NULL;
 296         int ret;
 297
 298         _enter("");
 299
 300         /* allocate a superblock info record */
 301         as = kzalloc(sizeof(struct afs_super_info), GFP_KERNEL);
 302         if (!as) {
 303                 _leave(" = -ENOMEM");
 304                 return -ENOMEM;
 305         }
 306
 307         afs_get_volume(params->volume);
 308         as->volume = params->volume;
 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_fs_info           = as;
 316
 317         /* allocate the root inode and dentry */
 318         fid.vid         = as->volume->vid;
 319         fid.vnode       = 1;
 320         fid.unique      = 1;
 321         inode = afs_iget(sb, params->key, &fid, NULL, NULL);
 322         if (IS_ERR(inode))
 323                 goto error_inode;
 324
 325         ret = -ENOMEM;
 326         root = d_alloc_root(inode);
 327         if (!root)
 328                 goto error;
 329
 330         sb->s_root = root;
 331
 332         _leave(" = 0");
 333         return 0;
 334
 335 error_inode:
 336         ret = PTR_ERR(inode);
 337         inode = NULL;
 338 error:
 339         iput(inode);
 340         afs_put_volume(as->volume);
 341         kfree(as);
 342
 343         sb->s_fs_info = NULL;
 344
 345         _leave(" = %d", ret);
 346         return ret;
 347 }
 348
 349 /*
 350  * get an AFS superblock
 351  */
 352 static int afs_get_sb(struct file_system_type *fs_type,
 353                       int flags,
 354                       const char *dev_name,
 355                       void *options,
 356                       struct vfsmount *mnt)
 357 {
 358         struct afs_mount_params params;
 359         struct super_block *sb;
 360         struct afs_volume *vol;
 361         struct key *key;
 362         int ret;
 363
 364         _enter(",,%s,%p", dev_name, options);
 365
 366         memset(&params, 0, sizeof(params));
 367
 368         /* parse the options and device name */
 369         if (options) {
 370                 ret = afs_parse_options(&params, options, &dev_name);
 371                 if (ret < 0)
 372                         goto error;
 373         }
 374
 375         ret = afs_parse_device_name(&params, dev_name);
 376         if (ret < 0)
 377                 goto error;
 378
 379         /* try and do the mount securely */
 380         key = afs_request_key(params.cell);
 381         if (IS_ERR(key)) {
 382                 _leave(" = %ld [key]", PTR_ERR(key));
 383                 ret = PTR_ERR(key);
 384                 goto error;
 385         }
 386         params.key = key;
 387
 388         /* parse the device name */
 389         vol = afs_volume_lookup(&params);
 390         if (IS_ERR(vol)) {
 391                 ret = PTR_ERR(vol);
 392                 goto error;
 393         }
 394         params.volume = vol;
 395
 396         /* allocate a deviceless superblock */
 397         sb = sget(fs_type, afs_test_super, set_anon_super, &params);
 398         if (IS_ERR(sb)) {
 399                 ret = PTR_ERR(sb);
 400                 goto error;
 401         }
 402
 403         if (!sb->s_root) {
 404                 /* initial superblock/root creation */
 405                 _debug("create");
 406                 sb->s_flags = flags;
 407                 ret = afs_fill_super(sb, &params);
 408                 if (ret < 0) {
 409                         up_write(&sb->s_umount);
 410                         deactivate_super(sb);
 411                         goto error;
 412                 }
 413                 sb->s_flags |= MS_ACTIVE;
 414         } else {
 415                 _debug("reuse");
 416                 ASSERTCMP(sb->s_flags, &, MS_ACTIVE);
 417         }
 418
 419         simple_set_mnt(mnt, sb);
 420         afs_put_volume(params.volume);
 421         afs_put_cell(params.cell);
 422         _leave(" = 0 [%p]", sb);
 423         return 0;
 424
 425 error:
 426         afs_put_volume(params.volume);
 427         afs_put_cell(params.cell);
 428         key_put(params.key);
 429         _leave(" = %d", ret);
 430         return ret;
 431 }
 432
 433 /*
 434  * finish the unmounting process on the superblock
 435  */
 436 static void afs_put_super(struct super_block *sb)
 437 {
 438         struct afs_super_info *as = sb->s_fs_info;
 439
 440         _enter("");
 441
 442         afs_put_volume(as->volume);
 443
 444         _leave("");
 445 }
 446
 447 /*
 448  * initialise an inode cache slab element prior to any use
 449  */
 450 static void afs_i_init_once(void *_vnode, struct kmem_cache *cachep,
 451                             unsigned long flags)
 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_WORK(&vnode->cb_broken_work, afs_broken_callback_work);
 464 }
 465
 466 /*
 467  * allocate an AFS inode struct from our slab cache
 468  */
 469 static struct inode *afs_alloc_inode(struct super_block *sb)
 470 {
 471         struct afs_vnode *vnode;
 472
 473         vnode = kmem_cache_alloc(afs_inode_cachep, GFP_KERNEL);
 474         if (!vnode)
 475                 return NULL;
 476
 477         atomic_inc(&afs_count_active_inodes);
 478
 479         memset(&vnode->fid, 0, sizeof(vnode->fid));
 480         memset(&vnode->status, 0, sizeof(vnode->status));
 481
 482         vnode->volume           = NULL;
 483         vnode->update_cnt       = 0;
 484         vnode->flags            = 1 << AFS_VNODE_UNSET;
 485         vnode->cb_promised      = false;
 486
 487         _leave(" = %p", &vnode->vfs_inode);
 488         return &vnode->vfs_inode;
 489 }
 490
 491 /*
 492  * destroy an AFS inode struct
 493  */
 494 static void afs_destroy_inode(struct inode *inode)
 495 {
 496         struct afs_vnode *vnode = AFS_FS_I(inode);
 497
 498         _enter("%p{%x:%u}", inode, vnode->fid.vid, vnode->fid.vnode);
 499
 500         _debug("DESTROY INODE %p", inode);
 501
 502         ASSERTCMP(vnode->server, ==, NULL);
 503
 504         kmem_cache_free(afs_inode_cachep, vnode);
 505         atomic_dec(&afs_count_active_inodes);
 506 }
 507
 508 /*
 509  * return information about an AFS volume
 510  */
 511 static int afs_statfs(struct dentry *dentry, struct kstatfs *buf)
 512 {
 513         struct afs_volume_status vs;
 514         struct afs_vnode *vnode = AFS_FS_I(dentry->d_inode);
 515         struct key *key;
 516         int ret;
 517
 518         key = afs_request_key(vnode->volume->cell);
 519         if (IS_ERR(key))
 520                 return PTR_ERR(key);
 521
 522         ret = afs_vnode_get_volume_status(vnode, key, &vs);
 523         key_put(key);
 524         if (ret < 0) {
 525                 _leave(" = %d", ret);
 526                 return ret;
 527         }
 528
 529         buf->f_type     = dentry->d_sb->s_magic;
 530         buf->f_bsize    = AFS_BLOCK_SIZE;
 531         buf->f_namelen  = AFSNAMEMAX - 1;
 532
 533         if (vs.max_quota == 0)
 534                 buf->f_blocks = vs.part_max_blocks;
 535         else
 536                 buf->f_blocks = vs.max_quota;
 537         buf->f_bavail = buf->f_bfree = buf->f_blocks - vs.blocks_in_use;
 538         return 0;
 539 }