fs/fuse/inode.c

   1 /*
   2   FUSE: Filesystem in Userspace
   3   Copyright (C) 2001-2006  Miklos Szeredi <miklos@szeredi.hu>
   4
   5   This program can be distributed under the terms of the GNU GPL.
   6   See the file COPYING.
   7 */
   8
   9 #include "fuse_i.h"
  10
  11 #include <linux/pagemap.h>
  12 #include <linux/slab.h>
  13 #include <linux/file.h>
  14 #include <linux/mount.h>
  15 #include <linux/seq_file.h>
  16 #include <linux/init.h>
  17 #include <linux/module.h>
  18 #include <linux/parser.h>
  19 #include <linux/statfs.h>
  20
  21 MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
  22 MODULE_DESCRIPTION("Filesystem in Userspace");
  23 MODULE_LICENSE("GPL");
  24
  25 static kmem_cache_t *fuse_inode_cachep;
  26 static struct subsystem connections_subsys;
  27
  28 struct fuse_conn_attr {
  29         struct attribute attr;
  30         ssize_t (*show)(struct fuse_conn *, char *);
  31         ssize_t (*store)(struct fuse_conn *, const char *, size_t);
  32 };
  33
  34 #define FUSE_SUPER_MAGIC 0x65735546
  35
  36 struct fuse_mount_data {
  37         int fd;
  38         unsigned rootmode;
  39         unsigned user_id;
  40         unsigned group_id;
  41         unsigned fd_present : 1;
  42         unsigned rootmode_present : 1;
  43         unsigned user_id_present : 1;
  44         unsigned group_id_present : 1;
  45         unsigned flags;
  46         unsigned max_read;
  47 };
  48
  49 static struct inode *fuse_alloc_inode(struct super_block *sb)
  50 {
  51         struct inode *inode;
  52         struct fuse_inode *fi;
  53
  54         inode = kmem_cache_alloc(fuse_inode_cachep, SLAB_KERNEL);
  55         if (!inode)
  56                 return NULL;
  57
  58         fi = get_fuse_inode(inode);
  59         fi->i_time = jiffies - 1;
  60         fi->nodeid = 0;
  61         fi->nlookup = 0;
  62         fi->forget_req = fuse_request_alloc();
  63         if (!fi->forget_req) {
  64                 kmem_cache_free(fuse_inode_cachep, inode);
  65                 return NULL;
  66         }
  67
  68         return inode;
  69 }
  70
  71 static void fuse_destroy_inode(struct inode *inode)
  72 {
  73         struct fuse_inode *fi = get_fuse_inode(inode);
  74         if (fi->forget_req)
  75                 fuse_request_free(fi->forget_req);
  76         kmem_cache_free(fuse_inode_cachep, inode);
  77 }
  78
  79 static void fuse_read_inode(struct inode *inode)
  80 {
  81         /* No op */
  82 }
  83
  84 void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req,
  85                       unsigned long nodeid, u64 nlookup)
  86 {
  87         struct fuse_forget_in *inarg = &req->misc.forget_in;
  88         inarg->nlookup = nlookup;
  89         req->in.h.opcode = FUSE_FORGET;
  90         req->in.h.nodeid = nodeid;
  91         req->in.numargs = 1;
  92         req->in.args[0].size = sizeof(struct fuse_forget_in);
  93         req->in.args[0].value = inarg;
  94         request_send_noreply(fc, req);
  95 }
  96
  97 static void fuse_clear_inode(struct inode *inode)
  98 {
  99         if (inode->i_sb->s_flags & MS_ACTIVE) {
 100                 struct fuse_conn *fc = get_fuse_conn(inode);
 101                 struct fuse_inode *fi = get_fuse_inode(inode);
 102                 fuse_send_forget(fc, fi->forget_req, fi->nodeid, fi->nlookup);
 103                 fi->forget_req = NULL;
 104         }
 105 }
 106
 107 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr)
 108 {
 109         if (S_ISREG(inode->i_mode) && i_size_read(inode) != attr->size)
 110                 invalidate_inode_pages(inode->i_mapping);
 111
 112         inode->i_ino     = attr->ino;
 113         inode->i_mode    = (inode->i_mode & S_IFMT) + (attr->mode & 07777);
 114         inode->i_nlink   = attr->nlink;
 115         inode->i_uid     = attr->uid;
 116         inode->i_gid     = attr->gid;
 117         i_size_write(inode, attr->size);
 118         inode->i_blksize = PAGE_CACHE_SIZE;
 119         inode->i_blocks  = attr->blocks;
 120         inode->i_atime.tv_sec   = attr->atime;
 121         inode->i_atime.tv_nsec  = attr->atimensec;
 122         inode->i_mtime.tv_sec   = attr->mtime;
 123         inode->i_mtime.tv_nsec  = attr->mtimensec;
 124         inode->i_ctime.tv_sec   = attr->ctime;
 125         inode->i_ctime.tv_nsec  = attr->ctimensec;
 126 }
 127
 128 static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr)
 129 {
 130         inode->i_mode = attr->mode & S_IFMT;
 131         i_size_write(inode, attr->size);
 132         if (S_ISREG(inode->i_mode)) {
 133                 fuse_init_common(inode);
 134                 fuse_init_file_inode(inode);
 135         } else if (S_ISDIR(inode->i_mode))
 136                 fuse_init_dir(inode);
 137         else if (S_ISLNK(inode->i_mode))
 138                 fuse_init_symlink(inode);
 139         else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
 140                  S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
 141                 fuse_init_common(inode);
 142                 init_special_inode(inode, inode->i_mode,
 143                                    new_decode_dev(attr->rdev));
 144         } else
 145                 BUG();
 146 }
 147
 148 static int fuse_inode_eq(struct inode *inode, void *_nodeidp)
 149 {
 150         unsigned long nodeid = *(unsigned long *) _nodeidp;
 151         if (get_node_id(inode) == nodeid)
 152                 return 1;
 153         else
 154                 return 0;
 155 }
 156
 157 static int fuse_inode_set(struct inode *inode, void *_nodeidp)
 158 {
 159         unsigned long nodeid = *(unsigned long *) _nodeidp;
 160         get_fuse_inode(inode)->nodeid = nodeid;
 161         return 0;
 162 }
 163
 164 struct inode *fuse_iget(struct super_block *sb, unsigned long nodeid,
 165                         int generation, struct fuse_attr *attr)
 166 {
 167         struct inode *inode;
 168         struct fuse_inode *fi;
 169         struct fuse_conn *fc = get_fuse_conn_super(sb);
 170         int retried = 0;
 171
 172  retry:
 173         inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid);
 174         if (!inode)
 175                 return NULL;
 176
 177         if ((inode->i_state & I_NEW)) {
 178                 inode->i_flags |= S_NOATIME|S_NOCMTIME;
 179                 inode->i_generation = generation;
 180                 inode->i_data.backing_dev_info = &fc->bdi;
 181                 fuse_init_inode(inode, attr);
 182                 unlock_new_inode(inode);
 183         } else if ((inode->i_mode ^ attr->mode) & S_IFMT) {
 184                 BUG_ON(retried);
 185                 /* Inode has changed type, any I/O on the old should fail */
 186                 make_bad_inode(inode);
 187                 iput(inode);
 188                 retried = 1;
 189                 goto retry;
 190         }
 191
 192         fi = get_fuse_inode(inode);
 193         fi->nlookup ++;
 194         fuse_change_attributes(inode, attr);
 195         return inode;
 196 }
 197
 198 static void fuse_umount_begin(struct vfsmount *vfsmnt, int flags)
 199 {
 200         if (flags & MNT_FORCE)
 201                 fuse_abort_conn(get_fuse_conn_super(vfsmnt->mnt_sb));
 202 }
 203
 204 static void fuse_put_super(struct super_block *sb)
 205 {
 206         struct fuse_conn *fc = get_fuse_conn_super(sb);
 207
 208         down_write(&fc->sbput_sem);
 209         while (!list_empty(&fc->background))
 210                 fuse_release_background(fc,
 211                                         list_entry(fc->background.next,
 212                                                    struct fuse_req, bg_entry));
 213
 214         spin_lock(&fc->lock);
 215         fc->mounted = 0;
 216         fc->connected = 0;
 217         spin_unlock(&fc->lock);
 218         up_write(&fc->sbput_sem);
 219         /* Flush all readers on this fs */
 220         kill_fasync(&fc->fasync, SIGIO, POLL_IN);
 221         wake_up_all(&fc->waitq);
 222         kobject_del(&fc->kobj);
 223         kobject_put(&fc->kobj);
 224 }
 225
 226 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr)
 227 {
 228         stbuf->f_type    = FUSE_SUPER_MAGIC;
 229         stbuf->f_bsize   = attr->bsize;
 230         stbuf->f_frsize  = attr->frsize;
 231         stbuf->f_blocks  = attr->blocks;
 232         stbuf->f_bfree   = attr->bfree;
 233         stbuf->f_bavail  = attr->bavail;
 234         stbuf->f_files   = attr->files;
 235         stbuf->f_ffree   = attr->ffree;
 236         stbuf->f_namelen = attr->namelen;
 237         /* fsid is left zero */
 238 }
 239
 240 static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf)
 241 {
 242         struct super_block *sb = dentry->d_sb;
 243         struct fuse_conn *fc = get_fuse_conn_super(sb);
 244         struct fuse_req *req;
 245         struct fuse_statfs_out outarg;
 246         int err;
 247
 248         req = fuse_get_req(fc);
 249         if (IS_ERR(req))
 250                 return PTR_ERR(req);
 251
 252         memset(&outarg, 0, sizeof(outarg));
 253         req->in.numargs = 0;
 254         req->in.h.opcode = FUSE_STATFS;
 255         req->out.numargs = 1;
 256         req->out.args[0].size =
 257                 fc->minor < 4 ? FUSE_COMPAT_STATFS_SIZE : sizeof(outarg);
 258         req->out.args[0].value = &outarg;
 259         request_send(fc, req);
 260         err = req->out.h.error;
 261         if (!err)
 262                 convert_fuse_statfs(buf, &outarg.st);
 263         fuse_put_request(fc, req);
 264         return err;
 265 }
 266
 267 enum {
 268         OPT_FD,
 269         OPT_ROOTMODE,
 270         OPT_USER_ID,
 271         OPT_GROUP_ID,
 272         OPT_DEFAULT_PERMISSIONS,
 273         OPT_ALLOW_OTHER,
 274         OPT_MAX_READ,
 275         OPT_ERR
 276 };
 277
 278 static match_table_t tokens = {
 279         {OPT_FD,                        "fd=%u"},
 280         {OPT_ROOTMODE,                  "rootmode=%o"},
 281         {OPT_USER_ID,                   "user_id=%u"},
 282         {OPT_GROUP_ID,                  "group_id=%u"},
 283         {OPT_DEFAULT_PERMISSIONS,       "default_permissions"},
 284         {OPT_ALLOW_OTHER,               "allow_other"},
 285         {OPT_MAX_READ,                  "max_read=%u"},
 286         {OPT_ERR,                       NULL}
 287 };
 288
 289 static int parse_fuse_opt(char *opt, struct fuse_mount_data *d)
 290 {
 291         char *p;
 292         memset(d, 0, sizeof(struct fuse_mount_data));
 293         d->max_read = ~0;
 294
 295         while ((p = strsep(&opt, ",")) != NULL) {
 296                 int token;
 297                 int value;
 298                 substring_t args[MAX_OPT_ARGS];
 299                 if (!*p)
 300                         continue;
 301
 302                 token = match_token(p, tokens, args);
 303                 switch (token) {
 304                 case OPT_FD:
 305                         if (match_int(&args[0], &value))
 306                                 return 0;
 307                         d->fd = value;
 308                         d->fd_present = 1;
 309                         break;
 310
 311                 case OPT_ROOTMODE:
 312                         if (match_octal(&args[0], &value))
 313                                 return 0;
 314                         d->rootmode = value;
 315                         d->rootmode_present = 1;
 316                         break;
 317
 318                 case OPT_USER_ID:
 319                         if (match_int(&args[0], &value))
 320                                 return 0;
 321                         d->user_id = value;
 322                         d->user_id_present = 1;
 323                         break;
 324
 325                 case OPT_GROUP_ID:
 326                         if (match_int(&args[0], &value))
 327                                 return 0;
 328                         d->group_id = value;
 329                         d->group_id_present = 1;
 330                         break;
 331
 332                 case OPT_DEFAULT_PERMISSIONS:
 333                         d->flags |= FUSE_DEFAULT_PERMISSIONS;
 334                         break;
 335
 336                 case OPT_ALLOW_OTHER:
 337                         d->flags |= FUSE_ALLOW_OTHER;
 338                         break;
 339
 340                 case OPT_MAX_READ:
 341                         if (match_int(&args[0], &value))
 342                                 return 0;
 343                         d->max_read = value;
 344                         break;
 345
 346                 default:
 347                         return 0;
 348                 }
 349         }
 350
 351         if (!d->fd_present || !d->rootmode_present ||
 352             !d->user_id_present || !d->group_id_present)
 353                 return 0;
 354
 355         return 1;
 356 }
 357
 358 static int fuse_show_options(struct seq_file *m, struct vfsmount *mnt)
 359 {
 360         struct fuse_conn *fc = get_fuse_conn_super(mnt->mnt_sb);
 361
 362         seq_printf(m, ",user_id=%u", fc->user_id);
 363         seq_printf(m, ",group_id=%u", fc->group_id);
 364         if (fc->flags & FUSE_DEFAULT_PERMISSIONS)
 365                 seq_puts(m, ",default_permissions");
 366         if (fc->flags & FUSE_ALLOW_OTHER)
 367                 seq_puts(m, ",allow_other");
 368         if (fc->max_read != ~0)
 369                 seq_printf(m, ",max_read=%u", fc->max_read);
 370         return 0;
 371 }
 372
 373 static void fuse_conn_release(struct kobject *kobj)
 374 {
 375         kfree(get_fuse_conn_kobj(kobj));
 376 }
 377
 378 static struct fuse_conn *new_conn(void)
 379 {
 380         struct fuse_conn *fc;
 381
 382         fc = kzalloc(sizeof(*fc), GFP_KERNEL);
 383         if (fc) {
 384                 spin_lock_init(&fc->lock);
 385                 init_waitqueue_head(&fc->waitq);
 386                 init_waitqueue_head(&fc->blocked_waitq);
 387                 INIT_LIST_HEAD(&fc->pending);
 388                 INIT_LIST_HEAD(&fc->processing);
 389                 INIT_LIST_HEAD(&fc->io);
 390                 INIT_LIST_HEAD(&fc->background);
 391                 init_rwsem(&fc->sbput_sem);
 392                 kobj_set_kset_s(fc, connections_subsys);
 393                 kobject_init(&fc->kobj);
 394                 atomic_set(&fc->num_waiting, 0);
 395                 fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
 396                 fc->bdi.unplug_io_fn = default_unplug_io_fn;
 397                 fc->reqctr = 0;
 398                 fc->blocked = 1;
 399         }
 400         return fc;
 401 }
 402
 403 static struct inode *get_root_inode(struct super_block *sb, unsigned mode)
 404 {
 405         struct fuse_attr attr;
 406         memset(&attr, 0, sizeof(attr));
 407
 408         attr.mode = mode;
 409         attr.ino = FUSE_ROOT_ID;
 410         return fuse_iget(sb, 1, 0, &attr);
 411 }
 412
 413 static struct super_operations fuse_super_operations = {
 414         .alloc_inode    = fuse_alloc_inode,
 415         .destroy_inode  = fuse_destroy_inode,
 416         .read_inode     = fuse_read_inode,
 417         .clear_inode    = fuse_clear_inode,
 418         .put_super      = fuse_put_super,
 419         .umount_begin   = fuse_umount_begin,
 420         .statfs         = fuse_statfs,
 421         .show_options   = fuse_show_options,
 422 };
 423
 424 static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
 425 {
 426         struct fuse_init_out *arg = &req->misc.init_out;
 427
 428         if (req->out.h.error || arg->major != FUSE_KERNEL_VERSION)
 429                 fc->conn_error = 1;
 430         else {
 431                 unsigned long ra_pages;
 432
 433                 if (arg->minor >= 6) {
 434                         ra_pages = arg->max_readahead / PAGE_CACHE_SIZE;
 435                         if (arg->flags & FUSE_ASYNC_READ)
 436                                 fc->async_read = 1;
 437                 } else
 438                         ra_pages = fc->max_read / PAGE_CACHE_SIZE;
 439
 440                 fc->bdi.ra_pages = min(fc->bdi.ra_pages, ra_pages);
 441                 fc->minor = arg->minor;
 442                 fc->max_write = arg->minor < 5 ? 4096 : arg->max_write;
 443         }
 444         fuse_put_request(fc, req);
 445         fc->blocked = 0;
 446         wake_up_all(&fc->blocked_waitq);
 447 }
 448
 449 static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req)
 450 {
 451         struct fuse_init_in *arg = &req->misc.init_in;
 452
 453         arg->major = FUSE_KERNEL_VERSION;
 454         arg->minor = FUSE_KERNEL_MINOR_VERSION;
 455         arg->max_readahead = fc->bdi.ra_pages * PAGE_CACHE_SIZE;
 456         arg->flags |= FUSE_ASYNC_READ;
 457         req->in.h.opcode = FUSE_INIT;
 458         req->in.numargs = 1;
 459         req->in.args[0].size = sizeof(*arg);
 460         req->in.args[0].value = arg;
 461         req->out.numargs = 1;
 462         /* Variable length arguement used for backward compatibility
 463            with interface version < 7.5.  Rest of init_out is zeroed
 464            by do_get_request(), so a short reply is not a problem */
 465         req->out.argvar = 1;
 466         req->out.args[0].size = sizeof(struct fuse_init_out);
 467         req->out.args[0].value = &req->misc.init_out;
 468         req->end = process_init_reply;
 469         request_send_background(fc, req);
 470 }
 471
 472 static unsigned long long conn_id(void)
 473 {
 474         /* BKL is held for ->get_sb() */
 475         static unsigned long long ctr = 1;
 476         return ctr++;
 477 }
 478
 479 static int fuse_fill_super(struct super_block *sb, void *data, int silent)
 480 {
 481         struct fuse_conn *fc;
 482         struct inode *root;
 483         struct fuse_mount_data d;
 484         struct file *file;
 485         struct dentry *root_dentry;
 486         struct fuse_req *init_req;
 487         int err;
 488
 489         if (!parse_fuse_opt((char *) data, &d))
 490                 return -EINVAL;
 491
 492         sb->s_blocksize = PAGE_CACHE_SIZE;
 493         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
 494         sb->s_magic = FUSE_SUPER_MAGIC;
 495         sb->s_op = &fuse_super_operations;
 496         sb->s_maxbytes = MAX_LFS_FILESIZE;
 497
 498         file = fget(d.fd);
 499         if (!file)
 500                 return -EINVAL;
 501
 502         if (file->f_op != &fuse_dev_operations)
 503                 return -EINVAL;
 504
 505         fc = new_conn();
 506         if (!fc)
 507                 return -ENOMEM;
 508
 509         fc->flags = d.flags;
 510         fc->user_id = d.user_id;
 511         fc->group_id = d.group_id;
 512         fc->max_read = d.max_read;
 513
 514         /* Used by get_root_inode() */
 515         sb->s_fs_info = fc;
 516
 517         err = -ENOMEM;
 518         root = get_root_inode(sb, d.rootmode);
 519         if (!root)
 520                 goto err;
 521
 522         root_dentry = d_alloc_root(root);
 523         if (!root_dentry) {
 524                 iput(root);
 525                 goto err;
 526         }
 527
 528         init_req = fuse_request_alloc();
 529         if (!init_req)
 530                 goto err_put_root;
 531
 532         err = kobject_set_name(&fc->kobj, "%llu", conn_id());
 533         if (err)
 534                 goto err_free_req;
 535
 536         err = kobject_add(&fc->kobj);
 537         if (err)
 538                 goto err_free_req;
 539
 540         /* Setting file->private_data can't race with other mount()
 541            instances, since BKL is held for ->get_sb() */
 542         err = -EINVAL;
 543         if (file->private_data)
 544                 goto err_kobject_del;
 545
 546         sb->s_root = root_dentry;
 547         fc->mounted = 1;
 548         fc->connected = 1;
 549         kobject_get(&fc->kobj);
 550         file->private_data = fc;
 551         /*
 552          * atomic_dec_and_test() in fput() provides the necessary
 553          * memory barrier for file->private_data to be visible on all
 554          * CPUs after this
 555          */
 556         fput(file);
 557
 558         fuse_send_init(fc, init_req);
 559
 560         return 0;
 561
 562  err_kobject_del:
 563         kobject_del(&fc->kobj);
 564  err_free_req:
 565         fuse_request_free(init_req);
 566  err_put_root:
 567         dput(root_dentry);
 568  err:
 569         fput(file);
 570         kobject_put(&fc->kobj);
 571         return err;
 572 }
 573
 574 static int fuse_get_sb(struct file_system_type *fs_type,
 575                        int flags, const char *dev_name,
 576                        void *raw_data, struct vfsmount *mnt)
 577 {
 578         return get_sb_nodev(fs_type, flags, raw_data, fuse_fill_super, mnt);
 579 }
 580
 581 static struct file_system_type fuse_fs_type = {
 582         .owner          = THIS_MODULE,
 583         .name           = "fuse",
 584         .get_sb         = fuse_get_sb,
 585         .kill_sb        = kill_anon_super,
 586 };
 587
 588 static ssize_t fuse_conn_waiting_show(struct fuse_conn *fc, char *page)
 589 {
 590         return sprintf(page, "%i\n", atomic_read(&fc->num_waiting));
 591 }
 592
 593 static ssize_t fuse_conn_abort_store(struct fuse_conn *fc, const char *page,
 594                                      size_t count)
 595 {
 596         fuse_abort_conn(fc);
 597         return count;
 598 }
 599
 600 static struct fuse_conn_attr fuse_conn_waiting =
 601         __ATTR(waiting, 0400, fuse_conn_waiting_show, NULL);
 602 static struct fuse_conn_attr fuse_conn_abort =
 603         __ATTR(abort, 0600, NULL, fuse_conn_abort_store);
 604
 605 static struct attribute *fuse_conn_attrs[] = {
 606         &fuse_conn_waiting.attr,
 607         &fuse_conn_abort.attr,
 608         NULL,
 609 };
 610
 611 static ssize_t fuse_conn_attr_show(struct kobject *kobj,
 612                                    struct attribute *attr,
 613                                    char *page)
 614 {
 615         struct fuse_conn_attr *fca =
 616                 container_of(attr, struct fuse_conn_attr, attr);
 617
 618         if (fca->show)
 619                 return fca->show(get_fuse_conn_kobj(kobj), page);
 620         else
 621                 return -EACCES;
 622 }
 623
 624 static ssize_t fuse_conn_attr_store(struct kobject *kobj,
 625                                     struct attribute *attr,
 626                                     const char *page, size_t count)
 627 {
 628         struct fuse_conn_attr *fca =
 629                 container_of(attr, struct fuse_conn_attr, attr);
 630
 631         if (fca->store)
 632                 return fca->store(get_fuse_conn_kobj(kobj), page, count);
 633         else
 634                 return -EACCES;
 635 }
 636
 637 static struct sysfs_ops fuse_conn_sysfs_ops = {
 638         .show   = &fuse_conn_attr_show,
 639         .store  = &fuse_conn_attr_store,
 640 };
 641
 642 static struct kobj_type ktype_fuse_conn = {
 643         .release        = fuse_conn_release,
 644         .sysfs_ops      = &fuse_conn_sysfs_ops,
 645         .default_attrs  = fuse_conn_attrs,
 646 };
 647
 648 static decl_subsys(fuse, NULL, NULL);
 649 static decl_subsys(connections, &ktype_fuse_conn, NULL);
 650
 651 static void fuse_inode_init_once(void *foo, kmem_cache_t *cachep,
 652                                  unsigned long flags)
 653 {
 654         struct inode * inode = foo;
 655
 656         if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
 657             SLAB_CTOR_CONSTRUCTOR)
 658                 inode_init_once(inode);
 659 }
 660
 661 static int __init fuse_fs_init(void)
 662 {
 663         int err;
 664
 665         err = register_filesystem(&fuse_fs_type);
 666         if (err)
 667                 printk("fuse: failed to register filesystem\n");
 668         else {
 669                 fuse_inode_cachep = kmem_cache_create("fuse_inode",
 670                                                       sizeof(struct fuse_inode),
 671                                                       0, SLAB_HWCACHE_ALIGN,
 672                                                       fuse_inode_init_once, NULL);
 673                 if (!fuse_inode_cachep) {
 674                         unregister_filesystem(&fuse_fs_type);
 675                         err = -ENOMEM;
 676                 }
 677         }
 678
 679         return err;
 680 }
 681
 682 static void fuse_fs_cleanup(void)
 683 {
 684         unregister_filesystem(&fuse_fs_type);
 685         kmem_cache_destroy(fuse_inode_cachep);
 686 }
 687
 688 static int fuse_sysfs_init(void)
 689 {
 690         int err;
 691
 692         kset_set_kset_s(&fuse_subsys, fs_subsys);
 693         err = subsystem_register(&fuse_subsys);
 694         if (err)
 695                 goto out_err;
 696
 697         kset_set_kset_s(&connections_subsys, fuse_subsys);
 698         err = subsystem_register(&connections_subsys);
 699         if (err)
 700                 goto out_fuse_unregister;
 701
 702         return 0;
 703
 704  out_fuse_unregister:
 705         subsystem_unregister(&fuse_subsys);
 706  out_err:
 707         return err;
 708 }
 709
 710 static void fuse_sysfs_cleanup(void)
 711 {
 712         subsystem_unregister(&connections_subsys);
 713         subsystem_unregister(&fuse_subsys);
 714 }
 715
 716 static int __init fuse_init(void)
 717 {
 718         int res;
 719
 720         printk("fuse init (API version %i.%i)\n",
 721                FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);
 722
 723         res = fuse_fs_init();
 724         if (res)
 725                 goto err;
 726
 727         res = fuse_dev_init();
 728         if (res)
 729                 goto err_fs_cleanup;
 730
 731         res = fuse_sysfs_init();
 732         if (res)
 733                 goto err_dev_cleanup;
 734
 735         return 0;
 736
 737  err_dev_cleanup:
 738         fuse_dev_cleanup();
 739  err_fs_cleanup:
 740         fuse_fs_cleanup();
 741  err:
 742         return res;
 743 }
 744
 745 static void __exit fuse_exit(void)
 746 {
 747         printk(KERN_DEBUG "fuse exit\n");
 748
 749         fuse_sysfs_cleanup();
 750         fuse_fs_cleanup();
 751         fuse_dev_cleanup();
 752 }
 753
 754 module_init(fuse_init);
 755 module_exit(fuse_exit);