fs/fuse/inode.c

   1 /*
   2   FUSE: Filesystem in Userspace
   3   Copyright (C) 2001-2005  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 spinlock_t fuse_lock;
  26 static kmem_cache_t *fuse_inode_cachep;
  27 static struct subsystem connections_subsys;
  28
  29 struct fuse_conn_attr {
  30         struct attribute attr;
  31         ssize_t (*show)(struct fuse_conn *, char *);
  32         ssize_t (*store)(struct fuse_conn *, const char *, size_t);
  33 };
  34
  35 #define FUSE_SUPER_MAGIC 0x65735546
  36
  37 struct fuse_mount_data {
  38         int fd;
  39         unsigned rootmode;
  40         unsigned user_id;
  41         unsigned group_id;
  42         unsigned fd_present : 1;
  43         unsigned rootmode_present : 1;
  44         unsigned user_id_present : 1;
  45         unsigned group_id_present : 1;
  46         unsigned flags;
  47         unsigned max_read;
  48 };
  49
  50 static struct inode *fuse_alloc_inode(struct super_block *sb)
  51 {
  52         struct inode *inode;
  53         struct fuse_inode *fi;
  54
  55         inode = kmem_cache_alloc(fuse_inode_cachep, SLAB_KERNEL);
  56         if (!inode)
  57                 return NULL;
  58
  59         fi = get_fuse_inode(inode);
  60         fi->i_time = jiffies - 1;
  61         fi->nodeid = 0;
  62         fi->nlookup = 0;
  63         fi->forget_req = fuse_request_alloc();
  64         if (!fi->forget_req) {
  65                 kmem_cache_free(fuse_inode_cachep, inode);
  66                 return NULL;
  67         }
  68
  69         return inode;
  70 }
  71
  72 static void fuse_destroy_inode(struct inode *inode)
  73 {
  74         struct fuse_inode *fi = get_fuse_inode(inode);
  75         if (fi->forget_req)
  76                 fuse_request_free(fi->forget_req);
  77         kmem_cache_free(fuse_inode_cachep, inode);
  78 }
  79
  80 static void fuse_read_inode(struct inode *inode)
  81 {
  82         /* No op */
  83 }
  84
  85 void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req,
  86                       unsigned long nodeid, u64 nlookup)
  87 {
  88         struct fuse_forget_in *inarg = &req->misc.forget_in;
  89         inarg->nlookup = nlookup;
  90         req->in.h.opcode = FUSE_FORGET;
  91         req->in.h.nodeid = nodeid;
  92         req->in.numargs = 1;
  93         req->in.args[0].size = sizeof(struct fuse_forget_in);
  94         req->in.args[0].value = inarg;
  95         request_send_noreply(fc, req);
  96 }
  97
  98 static void fuse_clear_inode(struct inode *inode)
  99 {
 100         if (inode->i_sb->s_flags & MS_ACTIVE) {
 101                 struct fuse_conn *fc = get_fuse_conn(inode);
 102                 struct fuse_inode *fi = get_fuse_inode(inode);
 103                 fuse_send_forget(fc, fi->forget_req, fi->nodeid, fi->nlookup);
 104                 fi->forget_req = NULL;
 105         }
 106 }
 107
 108 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr)
 109 {
 110         if (S_ISREG(inode->i_mode) && i_size_read(inode) != attr->size)
 111                 invalidate_inode_pages(inode->i_mapping);
 112
 113         inode->i_ino     = attr->ino;
 114         inode->i_mode    = (inode->i_mode & S_IFMT) + (attr->mode & 07777);
 115         inode->i_nlink   = attr->nlink;
 116         inode->i_uid     = attr->uid;
 117         inode->i_gid     = attr->gid;
 118         i_size_write(inode, attr->size);
 119         inode->i_blksize = PAGE_CACHE_SIZE;
 120         inode->i_blocks  = attr->blocks;
 121         inode->i_atime.tv_sec   = attr->atime;
 122         inode->i_atime.tv_nsec  = attr->atimensec;
 123         inode->i_mtime.tv_sec   = attr->mtime;
 124         inode->i_mtime.tv_nsec  = attr->mtimensec;
 125         inode->i_ctime.tv_sec   = attr->ctime;
 126         inode->i_ctime.tv_nsec  = attr->ctimensec;
 127 }
 128
 129 static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr)
 130 {
 131         inode->i_mode = attr->mode & S_IFMT;
 132         i_size_write(inode, attr->size);
 133         if (S_ISREG(inode->i_mode)) {
 134                 fuse_init_common(inode);
 135                 fuse_init_file_inode(inode);
 136         } else if (S_ISDIR(inode->i_mode))
 137                 fuse_init_dir(inode);
 138         else if (S_ISLNK(inode->i_mode))
 139                 fuse_init_symlink(inode);
 140         else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
 141                  S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
 142                 fuse_init_common(inode);
 143                 init_special_inode(inode, inode->i_mode,
 144                                    new_decode_dev(attr->rdev));
 145         } else
 146                 BUG();
 147 }
 148
 149 static int fuse_inode_eq(struct inode *inode, void *_nodeidp)
 150 {
 151         unsigned long nodeid = *(unsigned long *) _nodeidp;
 152         if (get_node_id(inode) == nodeid)
 153                 return 1;
 154         else
 155                 return 0;
 156 }
 157
 158 static int fuse_inode_set(struct inode *inode, void *_nodeidp)
 159 {
 160         unsigned long nodeid = *(unsigned long *) _nodeidp;
 161         get_fuse_inode(inode)->nodeid = nodeid;
 162         return 0;
 163 }
 164
 165 struct inode *fuse_iget(struct super_block *sb, unsigned long nodeid,
 166                         int generation, struct fuse_attr *attr)
 167 {
 168         struct inode *inode;
 169         struct fuse_inode *fi;
 170         struct fuse_conn *fc = get_fuse_conn_super(sb);
 171         int retried = 0;
 172
 173  retry:
 174         inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid);
 175         if (!inode)
 176                 return NULL;
 177
 178         if ((inode->i_state & I_NEW)) {
 179                 inode->i_flags |= S_NOATIME|S_NOCMTIME;
 180                 inode->i_generation = generation;
 181                 inode->i_data.backing_dev_info = &fc->bdi;
 182                 fuse_init_inode(inode, attr);
 183                 unlock_new_inode(inode);
 184         } else if ((inode->i_mode ^ attr->mode) & S_IFMT) {
 185                 BUG_ON(retried);
 186                 /* Inode has changed type, any I/O on the old should fail */
 187                 make_bad_inode(inode);
 188                 iput(inode);
 189                 retried = 1;
 190                 goto retry;
 191         }
 192
 193         fi = get_fuse_inode(inode);
 194         fi->nlookup ++;
 195         fuse_change_attributes(inode, attr);
 196         return inode;
 197 }
 198
 199 static void fuse_umount_begin(struct super_block *sb)
 200 {
 201         fuse_abort_conn(get_fuse_conn_super(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(list_entry(fc->background.next,
 211                                                    struct fuse_req, bg_entry));
 212
 213         spin_lock(&fuse_lock);
 214         fc->mounted = 0;
 215         fc->connected = 0;
 216         spin_unlock(&fuse_lock);
 217         up_write(&fc->sbput_sem);
 218         /* Flush all readers on this fs */
 219         wake_up_all(&fc->waitq);
 220         kobject_del(&fc->kobj);
 221         kobject_put(&fc->kobj);
 222 }
 223
 224 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr)
 225 {
 226         stbuf->f_type    = FUSE_SUPER_MAGIC;
 227         stbuf->f_bsize   = attr->bsize;
 228         stbuf->f_frsize  = attr->frsize;
 229         stbuf->f_blocks  = attr->blocks;
 230         stbuf->f_bfree   = attr->bfree;
 231         stbuf->f_bavail  = attr->bavail;
 232         stbuf->f_files   = attr->files;
 233         stbuf->f_ffree   = attr->ffree;
 234         stbuf->f_namelen = attr->namelen;
 235         /* fsid is left zero */
 236 }
 237
 238 static int fuse_statfs(struct super_block *sb, struct kstatfs *buf)
 239 {
 240         struct fuse_conn *fc = get_fuse_conn_super(sb);
 241         struct fuse_req *req;
 242         struct fuse_statfs_out outarg;
 243         int err;
 244
 245         req = fuse_get_request(fc);
 246         if (!req)
 247                 return -EINTR;
 248
 249         memset(&outarg, 0, sizeof(outarg));
 250         req->in.numargs = 0;
 251         req->in.h.opcode = FUSE_STATFS;
 252         req->out.numargs = 1;
 253         req->out.args[0].size =
 254                 fc->minor < 4 ? FUSE_COMPAT_STATFS_SIZE : sizeof(outarg);
 255         req->out.args[0].value = &outarg;
 256         request_send(fc, req);
 257         err = req->out.h.error;
 258         if (!err)
 259                 convert_fuse_statfs(buf, &outarg.st);
 260         fuse_put_request(fc, req);
 261         return err;
 262 }
 263
 264 enum {
 265         OPT_FD,
 266         OPT_ROOTMODE,
 267         OPT_USER_ID,
 268         OPT_GROUP_ID,
 269         OPT_DEFAULT_PERMISSIONS,
 270         OPT_ALLOW_OTHER,
 271         OPT_MAX_READ,
 272         OPT_ERR
 273 };
 274
 275 static match_table_t tokens = {
 276         {OPT_FD,                        "fd=%u"},
 277         {OPT_ROOTMODE,                  "rootmode=%o"},
 278         {OPT_USER_ID,                   "user_id=%u"},
 279         {OPT_GROUP_ID,                  "group_id=%u"},
 280         {OPT_DEFAULT_PERMISSIONS,       "default_permissions"},
 281         {OPT_ALLOW_OTHER,               "allow_other"},
 282         {OPT_MAX_READ,                  "max_read=%u"},
 283         {OPT_ERR,                       NULL}
 284 };
 285
 286 static int parse_fuse_opt(char *opt, struct fuse_mount_data *d)
 287 {
 288         char *p;
 289         memset(d, 0, sizeof(struct fuse_mount_data));
 290         d->max_read = ~0;
 291
 292         while ((p = strsep(&opt, ",")) != NULL) {
 293                 int token;
 294                 int value;
 295                 substring_t args[MAX_OPT_ARGS];
 296                 if (!*p)
 297                         continue;
 298
 299                 token = match_token(p, tokens, args);
 300                 switch (token) {
 301                 case OPT_FD:
 302                         if (match_int(&args[0], &value))
 303                                 return 0;
 304                         d->fd = value;
 305                         d->fd_present = 1;
 306                         break;
 307
 308                 case OPT_ROOTMODE:
 309                         if (match_octal(&args[0], &value))
 310                                 return 0;
 311                         d->rootmode = value;
 312                         d->rootmode_present = 1;
 313                         break;
 314
 315                 case OPT_USER_ID:
 316                         if (match_int(&args[0], &value))
 317                                 return 0;
 318                         d->user_id = value;
 319                         d->user_id_present = 1;
 320                         break;
 321
 322                 case OPT_GROUP_ID:
 323                         if (match_int(&args[0], &value))
 324                                 return 0;
 325                         d->group_id = value;
 326                         d->group_id_present = 1;
 327                         break;
 328
 329                 case OPT_DEFAULT_PERMISSIONS:
 330                         d->flags |= FUSE_DEFAULT_PERMISSIONS;
 331                         break;
 332
 333                 case OPT_ALLOW_OTHER:
 334                         d->flags |= FUSE_ALLOW_OTHER;
 335                         break;
 336
 337                 case OPT_MAX_READ:
 338                         if (match_int(&args[0], &value))
 339                                 return 0;
 340                         d->max_read = value;
 341                         break;
 342
 343                 default:
 344                         return 0;
 345                 }
 346         }
 347
 348         if (!d->fd_present || !d->rootmode_present ||
 349             !d->user_id_present || !d->group_id_present)
 350                 return 0;
 351
 352         return 1;
 353 }
 354
 355 static int fuse_show_options(struct seq_file *m, struct vfsmount *mnt)
 356 {
 357         struct fuse_conn *fc = get_fuse_conn_super(mnt->mnt_sb);
 358
 359         seq_printf(m, ",user_id=%u", fc->user_id);
 360         seq_printf(m, ",group_id=%u", fc->group_id);
 361         if (fc->flags & FUSE_DEFAULT_PERMISSIONS)
 362                 seq_puts(m, ",default_permissions");
 363         if (fc->flags & FUSE_ALLOW_OTHER)
 364                 seq_puts(m, ",allow_other");
 365         if (fc->max_read != ~0)
 366                 seq_printf(m, ",max_read=%u", fc->max_read);
 367         return 0;
 368 }
 369
 370 static void fuse_conn_release(struct kobject *kobj)
 371 {
 372         struct fuse_conn *fc = get_fuse_conn_kobj(kobj);
 373
 374         while (!list_empty(&fc->unused_list)) {
 375                 struct fuse_req *req;
 376                 req = list_entry(fc->unused_list.next, struct fuse_req, list);
 377                 list_del(&req->list);
 378                 fuse_request_free(req);
 379         }
 380         kfree(fc);
 381 }
 382
 383 static struct fuse_conn *new_conn(void)
 384 {
 385         struct fuse_conn *fc;
 386
 387         fc = kzalloc(sizeof(*fc), GFP_KERNEL);
 388         if (fc) {
 389                 int i;
 390                 init_waitqueue_head(&fc->waitq);
 391                 INIT_LIST_HEAD(&fc->pending);
 392                 INIT_LIST_HEAD(&fc->processing);
 393                 INIT_LIST_HEAD(&fc->io);
 394                 INIT_LIST_HEAD(&fc->unused_list);
 395                 INIT_LIST_HEAD(&fc->background);
 396                 sema_init(&fc->outstanding_sem, 1); /* One for INIT */
 397                 init_rwsem(&fc->sbput_sem);
 398                 kobj_set_kset_s(fc, connections_subsys);
 399                 kobject_init(&fc->kobj);
 400                 atomic_set(&fc->num_waiting, 0);
 401                 for (i = 0; i < FUSE_MAX_OUTSTANDING; i++) {
 402                         struct fuse_req *req = fuse_request_alloc();
 403                         if (!req) {
 404                                 kobject_put(&fc->kobj);
 405                                 return NULL;
 406                         }
 407                         list_add(&req->list, &fc->unused_list);
 408                 }
 409                 fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
 410                 fc->bdi.unplug_io_fn = default_unplug_io_fn;
 411                 fc->reqctr = 0;
 412         }
 413         return fc;
 414 }
 415
 416 static struct fuse_conn *get_conn(struct file *file, struct super_block *sb)
 417 {
 418         struct fuse_conn *fc;
 419         int err;
 420
 421         err = -EINVAL;
 422         if (file->f_op != &fuse_dev_operations)
 423                 goto out_err;
 424
 425         err = -ENOMEM;
 426         fc = new_conn();
 427         if (!fc)
 428                 goto out_err;
 429
 430         spin_lock(&fuse_lock);
 431         err = -EINVAL;
 432         if (file->private_data)
 433                 goto out_unlock;
 434
 435         kobject_get(&fc->kobj);
 436         file->private_data = fc;
 437         spin_unlock(&fuse_lock);
 438         return fc;
 439
 440  out_unlock:
 441         spin_unlock(&fuse_lock);
 442         kobject_put(&fc->kobj);
 443  out_err:
 444         return ERR_PTR(err);
 445 }
 446
 447 static struct inode *get_root_inode(struct super_block *sb, unsigned mode)
 448 {
 449         struct fuse_attr attr;
 450         memset(&attr, 0, sizeof(attr));
 451
 452         attr.mode = mode;
 453         attr.ino = FUSE_ROOT_ID;
 454         return fuse_iget(sb, 1, 0, &attr);
 455 }
 456
 457 static struct super_operations fuse_super_operations = {
 458         .alloc_inode    = fuse_alloc_inode,
 459         .destroy_inode  = fuse_destroy_inode,
 460         .read_inode     = fuse_read_inode,
 461         .clear_inode    = fuse_clear_inode,
 462         .put_super      = fuse_put_super,
 463         .umount_begin   = fuse_umount_begin,
 464         .statfs         = fuse_statfs,
 465         .show_options   = fuse_show_options,
 466 };
 467
 468 static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
 469 {
 470         int i;
 471         struct fuse_init_out *arg = &req->misc.init_out;
 472
 473         if (req->out.h.error || arg->major != FUSE_KERNEL_VERSION)
 474                 fc->conn_error = 1;
 475         else {
 476                 unsigned long ra_pages;
 477
 478                 if (arg->minor >= 6) {
 479                         ra_pages = arg->max_readahead / PAGE_CACHE_SIZE;
 480                         if (arg->flags & FUSE_ASYNC_READ)
 481                                 fc->async_read = 1;
 482                 } else
 483                         ra_pages = fc->max_read / PAGE_CACHE_SIZE;
 484
 485                 fc->bdi.ra_pages = min(fc->bdi.ra_pages, ra_pages);
 486                 fc->minor = arg->minor;
 487                 fc->max_write = arg->minor < 5 ? 4096 : arg->max_write;
 488         }
 489
 490         /* After INIT reply is received other requests can go
 491            out.  So do (FUSE_MAX_OUTSTANDING - 1) number of
 492            up()s on outstanding_sem.  The last up() is done in
 493            fuse_putback_request() */
 494         for (i = 1; i < FUSE_MAX_OUTSTANDING; i++)
 495                 up(&fc->outstanding_sem);
 496
 497         fuse_put_request(fc, req);
 498 }
 499
 500 static void fuse_send_init(struct fuse_conn *fc)
 501 {
 502         /* This is called from fuse_read_super() so there's guaranteed
 503            to be exactly one request available */
 504         struct fuse_req *req = fuse_get_request(fc);
 505         struct fuse_init_in *arg = &req->misc.init_in;
 506
 507         arg->major = FUSE_KERNEL_VERSION;
 508         arg->minor = FUSE_KERNEL_MINOR_VERSION;
 509         arg->max_readahead = fc->bdi.ra_pages * PAGE_CACHE_SIZE;
 510         arg->flags |= FUSE_ASYNC_READ;
 511         req->in.h.opcode = FUSE_INIT;
 512         req->in.numargs = 1;
 513         req->in.args[0].size = sizeof(*arg);
 514         req->in.args[0].value = arg;
 515         req->out.numargs = 1;
 516         /* Variable length arguement used for backward compatibility
 517            with interface version < 7.5.  Rest of init_out is zeroed
 518            by do_get_request(), so a short reply is not a problem */
 519         req->out.argvar = 1;
 520         req->out.args[0].size = sizeof(struct fuse_init_out);
 521         req->out.args[0].value = &req->misc.init_out;
 522         req->end = process_init_reply;
 523         request_send_background(fc, req);
 524 }
 525
 526 static unsigned long long conn_id(void)
 527 {
 528         static unsigned long long ctr = 1;
 529         unsigned long long val;
 530         spin_lock(&fuse_lock);
 531         val = ctr++;
 532         spin_unlock(&fuse_lock);
 533         return val;
 534 }
 535
 536 static int fuse_fill_super(struct super_block *sb, void *data, int silent)
 537 {
 538         struct fuse_conn *fc;
 539         struct inode *root;
 540         struct fuse_mount_data d;
 541         struct file *file;
 542         struct dentry *root_dentry;
 543         int err;
 544
 545         if (!parse_fuse_opt((char *) data, &d))
 546                 return -EINVAL;
 547
 548         sb->s_blocksize = PAGE_CACHE_SIZE;
 549         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
 550         sb->s_magic = FUSE_SUPER_MAGIC;
 551         sb->s_op = &fuse_super_operations;
 552         sb->s_maxbytes = MAX_LFS_FILESIZE;
 553
 554         file = fget(d.fd);
 555         if (!file)
 556                 return -EINVAL;
 557
 558         fc = get_conn(file, sb);
 559         fput(file);
 560         if (IS_ERR(fc))
 561                 return PTR_ERR(fc);
 562
 563         fc->flags = d.flags;
 564         fc->user_id = d.user_id;
 565         fc->group_id = d.group_id;
 566         fc->max_read = d.max_read;
 567
 568         /* Used by get_root_inode() */
 569         sb->s_fs_info = fc;
 570
 571         err = -ENOMEM;
 572         root = get_root_inode(sb, d.rootmode);
 573         if (!root)
 574                 goto err;
 575
 576         root_dentry = d_alloc_root(root);
 577         if (!root_dentry) {
 578                 iput(root);
 579                 goto err;
 580         }
 581
 582         err = kobject_set_name(&fc->kobj, "%llu", conn_id());
 583         if (err)
 584                 goto err_put_root;
 585
 586         err = kobject_add(&fc->kobj);
 587         if (err)
 588                 goto err_put_root;
 589
 590         sb->s_root = root_dentry;
 591         spin_lock(&fuse_lock);
 592         fc->mounted = 1;
 593         fc->connected = 1;
 594         spin_unlock(&fuse_lock);
 595
 596         fuse_send_init(fc);
 597
 598         return 0;
 599
 600  err_put_root:
 601         dput(root_dentry);
 602  err:
 603         kobject_put(&fc->kobj);
 604         return err;
 605 }
 606
 607 static struct super_block *fuse_get_sb(struct file_system_type *fs_type,
 608                                        int flags, const char *dev_name,
 609                                        void *raw_data)
 610 {
 611         return get_sb_nodev(fs_type, flags, raw_data, fuse_fill_super);
 612 }
 613
 614 static struct file_system_type fuse_fs_type = {
 615         .owner          = THIS_MODULE,
 616         .name           = "fuse",
 617         .get_sb         = fuse_get_sb,
 618         .kill_sb        = kill_anon_super,
 619 };
 620
 621 static ssize_t fuse_conn_waiting_show(struct fuse_conn *fc, char *page)
 622 {
 623         return sprintf(page, "%i\n", atomic_read(&fc->num_waiting));
 624 }
 625
 626 static ssize_t fuse_conn_abort_store(struct fuse_conn *fc, const char *page,
 627                                      size_t count)
 628 {
 629         fuse_abort_conn(fc);
 630         return count;
 631 }
 632
 633 static struct fuse_conn_attr fuse_conn_waiting =
 634         __ATTR(waiting, 0400, fuse_conn_waiting_show, NULL);
 635 static struct fuse_conn_attr fuse_conn_abort =
 636         __ATTR(abort, 0600, NULL, fuse_conn_abort_store);
 637
 638 static struct attribute *fuse_conn_attrs[] = {
 639         &fuse_conn_waiting.attr,
 640         &fuse_conn_abort.attr,
 641         NULL,
 642 };
 643
 644 static ssize_t fuse_conn_attr_show(struct kobject *kobj,
 645                                    struct attribute *attr,
 646                                    char *page)
 647 {
 648         struct fuse_conn_attr *fca =
 649                 container_of(attr, struct fuse_conn_attr, attr);
 650
 651         if (fca->show)
 652                 return fca->show(get_fuse_conn_kobj(kobj), page);
 653         else
 654                 return -EACCES;
 655 }
 656
 657 static ssize_t fuse_conn_attr_store(struct kobject *kobj,
 658                                     struct attribute *attr,
 659                                     const char *page, size_t count)
 660 {
 661         struct fuse_conn_attr *fca =
 662                 container_of(attr, struct fuse_conn_attr, attr);
 663
 664         if (fca->store)
 665                 return fca->store(get_fuse_conn_kobj(kobj), page, count);
 666         else
 667                 return -EACCES;
 668 }
 669
 670 static struct sysfs_ops fuse_conn_sysfs_ops = {
 671         .show   = &fuse_conn_attr_show,
 672         .store  = &fuse_conn_attr_store,
 673 };
 674
 675 static struct kobj_type ktype_fuse_conn = {
 676         .release        = fuse_conn_release,
 677         .sysfs_ops      = &fuse_conn_sysfs_ops,
 678         .default_attrs  = fuse_conn_attrs,
 679 };
 680
 681 static decl_subsys(fuse, NULL, NULL);
 682 static decl_subsys(connections, &ktype_fuse_conn, NULL);
 683
 684 static void fuse_inode_init_once(void *foo, kmem_cache_t *cachep,
 685                                  unsigned long flags)
 686 {
 687         struct inode * inode = foo;
 688
 689         if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
 690             SLAB_CTOR_CONSTRUCTOR)
 691                 inode_init_once(inode);
 692 }
 693
 694 static int __init fuse_fs_init(void)
 695 {
 696         int err;
 697
 698         err = register_filesystem(&fuse_fs_type);
 699         if (err)
 700                 printk("fuse: failed to register filesystem\n");
 701         else {
 702                 fuse_inode_cachep = kmem_cache_create("fuse_inode",
 703                                                       sizeof(struct fuse_inode),
 704                                                       0, SLAB_HWCACHE_ALIGN,
 705                                                       fuse_inode_init_once, NULL);
 706                 if (!fuse_inode_cachep) {
 707                         unregister_filesystem(&fuse_fs_type);
 708                         err = -ENOMEM;
 709                 }
 710         }
 711
 712         return err;
 713 }
 714
 715 static void fuse_fs_cleanup(void)
 716 {
 717         unregister_filesystem(&fuse_fs_type);
 718         kmem_cache_destroy(fuse_inode_cachep);
 719 }
 720
 721 static int fuse_sysfs_init(void)
 722 {
 723         int err;
 724
 725         kset_set_kset_s(&fuse_subsys, fs_subsys);
 726         err = subsystem_register(&fuse_subsys);
 727         if (err)
 728                 goto out_err;
 729
 730         kset_set_kset_s(&connections_subsys, fuse_subsys);
 731         err = subsystem_register(&connections_subsys);
 732         if (err)
 733                 goto out_fuse_unregister;
 734
 735         return 0;
 736
 737  out_fuse_unregister:
 738         subsystem_unregister(&fuse_subsys);
 739  out_err:
 740         return err;
 741 }
 742
 743 static void fuse_sysfs_cleanup(void)
 744 {
 745         subsystem_unregister(&connections_subsys);
 746         subsystem_unregister(&fuse_subsys);
 747 }
 748
 749 static int __init fuse_init(void)
 750 {
 751         int res;
 752
 753         printk("fuse init (API version %i.%i)\n",
 754                FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);
 755
 756         spin_lock_init(&fuse_lock);
 757         res = fuse_fs_init();
 758         if (res)
 759                 goto err;
 760
 761         res = fuse_dev_init();
 762         if (res)
 763                 goto err_fs_cleanup;
 764
 765         res = fuse_sysfs_init();
 766         if (res)
 767                 goto err_dev_cleanup;
 768
 769         return 0;
 770
 771  err_dev_cleanup:
 772         fuse_dev_cleanup();
 773  err_fs_cleanup:
 774         fuse_fs_cleanup();
 775  err:
 776         return res;
 777 }
 778
 779 static void __exit fuse_exit(void)
 780 {
 781         printk(KERN_DEBUG "fuse exit\n");
 782
 783         fuse_sysfs_cleanup();
 784         fuse_fs_cleanup();
 785         fuse_dev_cleanup();
 786 }
 787
 788 module_init(fuse_init);
 789 module_exit(fuse_exit);