fs/fuse/inode.c

   1 /*
   2   FUSE: Filesystem in Userspace
   3   Copyright (C) 2001-2008  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/seq_file.h>
  15 #include <linux/init.h>
  16 #include <linux/module.h>
  17 #include <linux/moduleparam.h>
  18 #include <linux/parser.h>
  19 #include <linux/statfs.h>
  20 #include <linux/random.h>
  21 #include <linux/sched.h>
  22 #include <linux/exportfs.h>
  23
  24 MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
  25 MODULE_DESCRIPTION("Filesystem in Userspace");
  26 MODULE_LICENSE("GPL");
  27
  28 static struct kmem_cache *fuse_inode_cachep;
  29 struct list_head fuse_conn_list;
  30 DEFINE_MUTEX(fuse_mutex);
  31
  32 static int set_global_limit(const char *val, struct kernel_param *kp);
  33
  34 unsigned max_user_bgreq;
  35 module_param_call(max_user_bgreq, set_global_limit, param_get_uint,
  36                   &max_user_bgreq, 0644);
  37 __MODULE_PARM_TYPE(max_user_bgreq, "uint");
  38 MODULE_PARM_DESC(max_user_bgreq,
  39  "Global limit for the maximum number of backgrounded requests an "
  40  "unprivileged user can set");
  41
  42 unsigned max_user_congthresh;
  43 module_param_call(max_user_congthresh, set_global_limit, param_get_uint,
  44                   &max_user_congthresh, 0644);
  45 __MODULE_PARM_TYPE(max_user_congthresh, "uint");
  46 MODULE_PARM_DESC(max_user_congthresh,
  47  "Global limit for the maximum congestion threshold an "
  48  "unprivileged user can set");
  49
  50 #define FUSE_SUPER_MAGIC 0x65735546
  51
  52 #define FUSE_DEFAULT_BLKSIZE 512
  53
  54 /** Maximum number of outstanding background requests */
  55 #define FUSE_DEFAULT_MAX_BACKGROUND 12
  56
  57 /** Congestion starts at 75% of maximum */
  58 #define FUSE_DEFAULT_CONGESTION_THRESHOLD (FUSE_DEFAULT_MAX_BACKGROUND * 3 / 4)
  59
  60 struct fuse_mount_data {
  61         int fd;
  62         unsigned rootmode;
  63         kuid_t user_id;
  64         kgid_t group_id;
  65         unsigned fd_present:1;
  66         unsigned rootmode_present:1;
  67         unsigned user_id_present:1;
  68         unsigned group_id_present:1;
  69         unsigned flags;
  70         unsigned max_read;
  71         unsigned blksize;
  72 };
  73
  74 struct fuse_forget_link *fuse_alloc_forget(void)
  75 {
  76         return kzalloc(sizeof(struct fuse_forget_link), GFP_KERNEL);
  77 }
  78
  79 static struct inode *fuse_alloc_inode(struct super_block *sb)
  80 {
  81         struct inode *inode;
  82         struct fuse_inode *fi;
  83
  84         inode = kmem_cache_alloc(fuse_inode_cachep, GFP_KERNEL);
  85         if (!inode)
  86                 return NULL;
  87
  88         fi = get_fuse_inode(inode);
  89         fi->i_time = 0;
  90         fi->nodeid = 0;
  91         fi->nlookup = 0;
  92         fi->attr_version = 0;
  93         fi->writectr = 0;
  94         fi->orig_ino = 0;
  95         fi->state = 0;
  96         INIT_LIST_HEAD(&fi->write_files);
  97         INIT_LIST_HEAD(&fi->queued_writes);
  98         INIT_LIST_HEAD(&fi->writepages);
  99         init_waitqueue_head(&fi->page_waitq);
 100         fi->forget = fuse_alloc_forget();
 101         if (!fi->forget) {
 102                 kmem_cache_free(fuse_inode_cachep, inode);
 103                 return NULL;
 104         }
 105
 106         return inode;
 107 }
 108
 109 static void fuse_i_callback(struct rcu_head *head)
 110 {
 111         struct inode *inode = container_of(head, struct inode, i_rcu);
 112         kmem_cache_free(fuse_inode_cachep, inode);
 113 }
 114
 115 static void fuse_destroy_inode(struct inode *inode)
 116 {
 117         struct fuse_inode *fi = get_fuse_inode(inode);
 118         BUG_ON(!list_empty(&fi->write_files));
 119         BUG_ON(!list_empty(&fi->queued_writes));
 120         kfree(fi->forget);
 121         call_rcu(&inode->i_rcu, fuse_i_callback);
 122 }
 123
 124 static void fuse_evict_inode(struct inode *inode)
 125 {
 126         truncate_inode_pages_final(&inode->i_data);
 127         clear_inode(inode);
 128         if (inode->i_sb->s_flags & MS_ACTIVE) {
 129                 struct fuse_conn *fc = get_fuse_conn(inode);
 130                 struct fuse_inode *fi = get_fuse_inode(inode);
 131                 fuse_queue_forget(fc, fi->forget, fi->nodeid, fi->nlookup);
 132                 fi->forget = NULL;
 133         }
 134 }
 135
 136 static int fuse_remount_fs(struct super_block *sb, int *flags, char *data)
 137 {
 138         sync_filesystem(sb);
 139         if (*flags & MS_MANDLOCK)
 140                 return -EINVAL;
 141
 142         return 0;
 143 }
 144
 145 /*
 146  * ino_t is 32-bits on 32-bit arch. We have to squash the 64-bit value down
 147  * so that it will fit.
 148  */
 149 static ino_t fuse_squash_ino(u64 ino64)
 150 {
 151         ino_t ino = (ino_t) ino64;
 152         if (sizeof(ino_t) < sizeof(u64))
 153                 ino ^= ino64 >> (sizeof(u64) - sizeof(ino_t)) * 8;
 154         return ino;
 155 }
 156
 157 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
 158                                    u64 attr_valid)
 159 {
 160         struct fuse_conn *fc = get_fuse_conn(inode);
 161         struct fuse_inode *fi = get_fuse_inode(inode);
 162
 163         fi->attr_version = ++fc->attr_version;
 164         fi->i_time = attr_valid;
 165
 166         inode->i_ino     = fuse_squash_ino(attr->ino);
 167         inode->i_mode    = (inode->i_mode & S_IFMT) | (attr->mode & 07777);
 168         set_nlink(inode, attr->nlink);
 169         inode->i_uid     = make_kuid(&init_user_ns, attr->uid);
 170         inode->i_gid     = make_kgid(&init_user_ns, attr->gid);
 171         inode->i_blocks  = attr->blocks;
 172         inode->i_atime.tv_sec   = attr->atime;
 173         inode->i_atime.tv_nsec  = attr->atimensec;
 174         /* mtime from server may be stale due to local buffered write */
 175         if (!fc->writeback_cache || !S_ISREG(inode->i_mode)) {
 176                 inode->i_mtime.tv_sec   = attr->mtime;
 177                 inode->i_mtime.tv_nsec  = attr->mtimensec;
 178                 inode->i_ctime.tv_sec   = attr->ctime;
 179                 inode->i_ctime.tv_nsec  = attr->ctimensec;
 180         }
 181
 182         if (attr->blksize != 0)
 183                 inode->i_blkbits = ilog2(attr->blksize);
 184         else
 185                 inode->i_blkbits = inode->i_sb->s_blocksize_bits;
 186
 187         /*
 188          * Don't set the sticky bit in i_mode, unless we want the VFS
 189          * to check permissions.  This prevents failures due to the
 190          * check in may_delete().
 191          */
 192         fi->orig_i_mode = inode->i_mode;
 193         if (!(fc->flags & FUSE_DEFAULT_PERMISSIONS))
 194                 inode->i_mode &= ~S_ISVTX;
 195
 196         fi->orig_ino = attr->ino;
 197 }
 198
 199 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
 200                             u64 attr_valid, u64 attr_version)
 201 {
 202         struct fuse_conn *fc = get_fuse_conn(inode);
 203         struct fuse_inode *fi = get_fuse_inode(inode);
 204         bool is_wb = fc->writeback_cache;
 205         loff_t oldsize;
 206         struct timespec old_mtime;
 207
 208         spin_lock(&fc->lock);
 209         if ((attr_version != 0 && fi->attr_version > attr_version) ||
 210             test_bit(FUSE_I_SIZE_UNSTABLE, &fi->state)) {
 211                 spin_unlock(&fc->lock);
 212                 return;
 213         }
 214
 215         old_mtime = inode->i_mtime;
 216         fuse_change_attributes_common(inode, attr, attr_valid);
 217
 218         oldsize = inode->i_size;
 219         /*
 220          * In case of writeback_cache enabled, the cached writes beyond EOF
 221          * extend local i_size without keeping userspace server in sync. So,
 222          * attr->size coming from server can be stale. We cannot trust it.
 223          */
 224         if (!is_wb || !S_ISREG(inode->i_mode))
 225                 i_size_write(inode, attr->size);
 226         spin_unlock(&fc->lock);
 227
 228         if (!is_wb && S_ISREG(inode->i_mode)) {
 229                 bool inval = false;
 230
 231                 if (oldsize != attr->size) {
 232                         truncate_pagecache(inode, attr->size);
 233                         inval = true;
 234                 } else if (fc->auto_inval_data) {
 235                         struct timespec new_mtime = {
 236                                 .tv_sec = attr->mtime,
 237                                 .tv_nsec = attr->mtimensec,
 238                         };
 239
 240                         /*
 241                          * Auto inval mode also checks and invalidates if mtime
 242                          * has changed.
 243                          */
 244                         if (!timespec_equal(&old_mtime, &new_mtime))
 245                                 inval = true;
 246                 }
 247
 248                 if (inval)
 249                         invalidate_inode_pages2(inode->i_mapping);
 250         }
 251 }
 252
 253 static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr)
 254 {
 255         inode->i_mode = attr->mode & S_IFMT;
 256         inode->i_size = attr->size;
 257         inode->i_mtime.tv_sec  = attr->mtime;
 258         inode->i_mtime.tv_nsec = attr->mtimensec;
 259         inode->i_ctime.tv_sec  = attr->ctime;
 260         inode->i_ctime.tv_nsec = attr->ctimensec;
 261         if (S_ISREG(inode->i_mode)) {
 262                 fuse_init_common(inode);
 263                 fuse_init_file_inode(inode);
 264         } else if (S_ISDIR(inode->i_mode))
 265                 fuse_init_dir(inode);
 266         else if (S_ISLNK(inode->i_mode))
 267                 fuse_init_symlink(inode);
 268         else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
 269                  S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
 270                 fuse_init_common(inode);
 271                 init_special_inode(inode, inode->i_mode,
 272                                    new_decode_dev(attr->rdev));
 273         } else
 274                 BUG();
 275 }
 276
 277 int fuse_inode_eq(struct inode *inode, void *_nodeidp)
 278 {
 279         u64 nodeid = *(u64 *) _nodeidp;
 280         if (get_node_id(inode) == nodeid)
 281                 return 1;
 282         else
 283                 return 0;
 284 }
 285
 286 static int fuse_inode_set(struct inode *inode, void *_nodeidp)
 287 {
 288         u64 nodeid = *(u64 *) _nodeidp;
 289         get_fuse_inode(inode)->nodeid = nodeid;
 290         return 0;
 291 }
 292
 293 struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
 294                         int generation, struct fuse_attr *attr,
 295                         u64 attr_valid, u64 attr_version)
 296 {
 297         struct inode *inode;
 298         struct fuse_inode *fi;
 299         struct fuse_conn *fc = get_fuse_conn_super(sb);
 300
 301  retry:
 302         inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid);
 303         if (!inode)
 304                 return NULL;
 305
 306         if ((inode->i_state & I_NEW)) {
 307                 inode->i_flags |= S_NOATIME;
 308                 if (!fc->writeback_cache || !S_ISREG(attr->mode))
 309                         inode->i_flags |= S_NOCMTIME;
 310                 inode->i_generation = generation;
 311                 fuse_init_inode(inode, attr);
 312                 unlock_new_inode(inode);
 313         } else if ((inode->i_mode ^ attr->mode) & S_IFMT) {
 314                 /* Inode has changed type, any I/O on the old should fail */
 315                 make_bad_inode(inode);
 316                 iput(inode);
 317                 goto retry;
 318         }
 319
 320         fi = get_fuse_inode(inode);
 321         spin_lock(&fc->lock);
 322         fi->nlookup++;
 323         spin_unlock(&fc->lock);
 324         fuse_change_attributes(inode, attr, attr_valid, attr_version);
 325
 326         return inode;
 327 }
 328
 329 int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid,
 330                              loff_t offset, loff_t len)
 331 {
 332         struct inode *inode;
 333         pgoff_t pg_start;
 334         pgoff_t pg_end;
 335
 336         inode = ilookup5(sb, nodeid, fuse_inode_eq, &nodeid);
 337         if (!inode)
 338                 return -ENOENT;
 339
 340         fuse_invalidate_attr(inode);
 341         if (offset >= 0) {
 342                 pg_start = offset >> PAGE_CACHE_SHIFT;
 343                 if (len <= 0)
 344                         pg_end = -1;
 345                 else
 346                         pg_end = (offset + len - 1) >> PAGE_CACHE_SHIFT;
 347                 invalidate_inode_pages2_range(inode->i_mapping,
 348                                               pg_start, pg_end);
 349         }
 350         iput(inode);
 351         return 0;
 352 }
 353
 354 static void fuse_umount_begin(struct super_block *sb)
 355 {
 356         fuse_abort_conn(get_fuse_conn_super(sb));
 357 }
 358
 359 static void fuse_send_destroy(struct fuse_conn *fc)
 360 {
 361         struct fuse_req *req = fc->destroy_req;
 362         if (req && fc->conn_init) {
 363                 fc->destroy_req = NULL;
 364                 req->in.h.opcode = FUSE_DESTROY;
 365                 __set_bit(FR_FORCE, &req->flags);
 366                 __clear_bit(FR_BACKGROUND, &req->flags);
 367                 fuse_request_send(fc, req);
 368                 fuse_put_request(fc, req);
 369         }
 370 }
 371
 372 static void fuse_bdi_destroy(struct fuse_conn *fc)
 373 {
 374         if (fc->bdi_initialized)
 375                 bdi_destroy(&fc->bdi);
 376 }
 377
 378 static void fuse_put_super(struct super_block *sb)
 379 {
 380         struct fuse_conn *fc = get_fuse_conn_super(sb);
 381
 382         fuse_send_destroy(fc);
 383
 384         fuse_abort_conn(fc);
 385         mutex_lock(&fuse_mutex);
 386         list_del(&fc->entry);
 387         fuse_ctl_remove_conn(fc);
 388         mutex_unlock(&fuse_mutex);
 389         fuse_bdi_destroy(fc);
 390
 391         fuse_conn_put(fc);
 392 }
 393
 394 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr)
 395 {
 396         stbuf->f_type    = FUSE_SUPER_MAGIC;
 397         stbuf->f_bsize   = attr->bsize;
 398         stbuf->f_frsize  = attr->frsize;
 399         stbuf->f_blocks  = attr->blocks;
 400         stbuf->f_bfree   = attr->bfree;
 401         stbuf->f_bavail  = attr->bavail;
 402         stbuf->f_files   = attr->files;
 403         stbuf->f_ffree   = attr->ffree;
 404         stbuf->f_namelen = attr->namelen;
 405         /* fsid is left zero */
 406 }
 407
 408 static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf)
 409 {
 410         struct super_block *sb = dentry->d_sb;
 411         struct fuse_conn *fc = get_fuse_conn_super(sb);
 412         FUSE_ARGS(args);
 413         struct fuse_statfs_out outarg;
 414         int err;
 415
 416         if (!fuse_allow_current_process(fc)) {
 417                 buf->f_type = FUSE_SUPER_MAGIC;
 418                 return 0;
 419         }
 420
 421         memset(&outarg, 0, sizeof(outarg));
 422         args.in.numargs = 0;
 423         args.in.h.opcode = FUSE_STATFS;
 424         args.in.h.nodeid = get_node_id(d_inode(dentry));
 425         args.out.numargs = 1;
 426         args.out.args[0].size = sizeof(outarg);
 427         args.out.args[0].value = &outarg;
 428         err = fuse_simple_request(fc, &args);
 429         if (!err)
 430                 convert_fuse_statfs(buf, &outarg.st);
 431         return err;
 432 }
 433
 434 enum {
 435         OPT_FD,
 436         OPT_ROOTMODE,
 437         OPT_USER_ID,
 438         OPT_GROUP_ID,
 439         OPT_DEFAULT_PERMISSIONS,
 440         OPT_ALLOW_OTHER,
 441         OPT_MAX_READ,
 442         OPT_BLKSIZE,
 443         OPT_ERR
 444 };
 445
 446 static const match_table_t tokens = {
 447         {OPT_FD,                        "fd=%u"},
 448         {OPT_ROOTMODE,                  "rootmode=%o"},
 449         {OPT_USER_ID,                   "user_id=%u"},
 450         {OPT_GROUP_ID,                  "group_id=%u"},
 451         {OPT_DEFAULT_PERMISSIONS,       "default_permissions"},
 452         {OPT_ALLOW_OTHER,               "allow_other"},
 453         {OPT_MAX_READ,                  "max_read=%u"},
 454         {OPT_BLKSIZE,                   "blksize=%u"},
 455         {OPT_ERR,                       NULL}
 456 };
 457
 458 static int fuse_match_uint(substring_t *s, unsigned int *res)
 459 {
 460         int err = -ENOMEM;
 461         char *buf = match_strdup(s);
 462         if (buf) {
 463                 err = kstrtouint(buf, 10, res);
 464                 kfree(buf);
 465         }
 466         return err;
 467 }
 468
 469 static int parse_fuse_opt(char *opt, struct fuse_mount_data *d, int is_bdev)
 470 {
 471         char *p;
 472         memset(d, 0, sizeof(struct fuse_mount_data));
 473         d->max_read = ~0;
 474         d->blksize = FUSE_DEFAULT_BLKSIZE;
 475
 476         while ((p = strsep(&opt, ",")) != NULL) {
 477                 int token;
 478                 int value;
 479                 unsigned uv;
 480                 substring_t args[MAX_OPT_ARGS];
 481                 if (!*p)
 482                         continue;
 483
 484                 token = match_token(p, tokens, args);
 485                 switch (token) {
 486                 case OPT_FD:
 487                         if (match_int(&args[0], &value))
 488                                 return 0;
 489                         d->fd = value;
 490                         d->fd_present = 1;
 491                         break;
 492
 493                 case OPT_ROOTMODE:
 494                         if (match_octal(&args[0], &value))
 495                                 return 0;
 496                         if (!fuse_valid_type(value))
 497                                 return 0;
 498                         d->rootmode = value;
 499                         d->rootmode_present = 1;
 500                         break;
 501
 502                 case OPT_USER_ID:
 503                         if (fuse_match_uint(&args[0], &uv))
 504                                 return 0;
 505                         d->user_id = make_kuid(current_user_ns(), uv);
 506                         if (!uid_valid(d->user_id))
 507                                 return 0;
 508                         d->user_id_present = 1;
 509                         break;
 510
 511                 case OPT_GROUP_ID:
 512                         if (fuse_match_uint(&args[0], &uv))
 513                                 return 0;
 514                         d->group_id = make_kgid(current_user_ns(), uv);
 515                         if (!gid_valid(d->group_id))
 516                                 return 0;
 517                         d->group_id_present = 1;
 518                         break;
 519
 520                 case OPT_DEFAULT_PERMISSIONS:
 521                         d->flags |= FUSE_DEFAULT_PERMISSIONS;
 522                         break;
 523
 524                 case OPT_ALLOW_OTHER:
 525                         d->flags |= FUSE_ALLOW_OTHER;
 526                         break;
 527
 528                 case OPT_MAX_READ:
 529                         if (match_int(&args[0], &value))
 530                                 return 0;
 531                         d->max_read = value;
 532                         break;
 533
 534                 case OPT_BLKSIZE:
 535                         if (!is_bdev || match_int(&args[0], &value))
 536                                 return 0;
 537                         d->blksize = value;
 538                         break;
 539
 540                 default:
 541                         return 0;
 542                 }
 543         }
 544
 545         if (!d->fd_present || !d->rootmode_present ||
 546             !d->user_id_present || !d->group_id_present)
 547                 return 0;
 548
 549         return 1;
 550 }
 551
 552 static int fuse_show_options(struct seq_file *m, struct dentry *root)
 553 {
 554         struct super_block *sb = root->d_sb;
 555         struct fuse_conn *fc = get_fuse_conn_super(sb);
 556
 557         seq_printf(m, ",user_id=%u", from_kuid_munged(&init_user_ns, fc->user_id));
 558         seq_printf(m, ",group_id=%u", from_kgid_munged(&init_user_ns, fc->group_id));
 559         if (fc->flags & FUSE_DEFAULT_PERMISSIONS)
 560                 seq_puts(m, ",default_permissions");
 561         if (fc->flags & FUSE_ALLOW_OTHER)
 562                 seq_puts(m, ",allow_other");
 563         if (fc->max_read != ~0)
 564                 seq_printf(m, ",max_read=%u", fc->max_read);
 565         if (sb->s_bdev && sb->s_blocksize != FUSE_DEFAULT_BLKSIZE)
 566                 seq_printf(m, ",blksize=%lu", sb->s_blocksize);
 567         return 0;
 568 }
 569
 570 static void fuse_iqueue_init(struct fuse_iqueue *fiq)
 571 {
 572         memset(fiq, 0, sizeof(struct fuse_iqueue));
 573         init_waitqueue_head(&fiq->waitq);
 574         INIT_LIST_HEAD(&fiq->pending);
 575         INIT_LIST_HEAD(&fiq->interrupts);
 576         fiq->forget_list_tail = &fiq->forget_list_head;
 577         fiq->connected = 1;
 578 }
 579
 580 static void fuse_pqueue_init(struct fuse_pqueue *fpq)
 581 {
 582         memset(fpq, 0, sizeof(struct fuse_pqueue));
 583         spin_lock_init(&fpq->lock);
 584         INIT_LIST_HEAD(&fpq->processing);
 585         INIT_LIST_HEAD(&fpq->io);
 586         fpq->connected = 1;
 587 }
 588
 589 void fuse_conn_init(struct fuse_conn *fc)
 590 {
 591         memset(fc, 0, sizeof(*fc));
 592         spin_lock_init(&fc->lock);
 593         init_rwsem(&fc->killsb);
 594         atomic_set(&fc->count, 1);
 595         atomic_set(&fc->dev_count, 1);
 596         init_waitqueue_head(&fc->blocked_waitq);
 597         init_waitqueue_head(&fc->reserved_req_waitq);
 598         fuse_iqueue_init(&fc->iq);
 599         INIT_LIST_HEAD(&fc->bg_queue);
 600         INIT_LIST_HEAD(&fc->entry);
 601         INIT_LIST_HEAD(&fc->devices);
 602         atomic_set(&fc->num_waiting, 0);
 603         fc->max_background = FUSE_DEFAULT_MAX_BACKGROUND;
 604         fc->congestion_threshold = FUSE_DEFAULT_CONGESTION_THRESHOLD;
 605         fc->khctr = 0;
 606         fc->polled_files = RB_ROOT;
 607         fc->blocked = 0;
 608         fc->initialized = 0;
 609         fc->connected = 1;
 610         fc->attr_version = 1;
 611         get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key));
 612 }
 613 EXPORT_SYMBOL_GPL(fuse_conn_init);
 614
 615 void fuse_conn_put(struct fuse_conn *fc)
 616 {
 617         if (atomic_dec_and_test(&fc->count)) {
 618                 if (fc->destroy_req)
 619                         fuse_request_free(fc->destroy_req);
 620                 fc->release(fc);
 621         }
 622 }
 623 EXPORT_SYMBOL_GPL(fuse_conn_put);
 624
 625 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc)
 626 {
 627         atomic_inc(&fc->count);
 628         return fc;
 629 }
 630 EXPORT_SYMBOL_GPL(fuse_conn_get);
 631
 632 static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned mode)
 633 {
 634         struct fuse_attr attr;
 635         memset(&attr, 0, sizeof(attr));
 636
 637         attr.mode = mode;
 638         attr.ino = FUSE_ROOT_ID;
 639         attr.nlink = 1;
 640         return fuse_iget(sb, 1, 0, &attr, 0, 0);
 641 }
 642
 643 struct fuse_inode_handle {
 644         u64 nodeid;
 645         u32 generation;
 646 };
 647
 648 static struct dentry *fuse_get_dentry(struct super_block *sb,
 649                                       struct fuse_inode_handle *handle)
 650 {
 651         struct fuse_conn *fc = get_fuse_conn_super(sb);
 652         struct inode *inode;
 653         struct dentry *entry;
 654         int err = -ESTALE;
 655
 656         if (handle->nodeid == 0)
 657                 goto out_err;
 658
 659         inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid);
 660         if (!inode) {
 661                 struct fuse_entry_out outarg;
 662                 struct qstr name;
 663
 664                 if (!fc->export_support)
 665                         goto out_err;
 666
 667                 name.len = 1;
 668                 name.name = ".";
 669                 err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg,
 670                                        &inode);
 671                 if (err && err != -ENOENT)
 672                         goto out_err;
 673                 if (err || !inode) {
 674                         err = -ESTALE;
 675                         goto out_err;
 676                 }
 677                 err = -EIO;
 678                 if (get_node_id(inode) != handle->nodeid)
 679                         goto out_iput;
 680         }
 681         err = -ESTALE;
 682         if (inode->i_generation != handle->generation)
 683                 goto out_iput;
 684
 685         entry = d_obtain_alias(inode);
 686         if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID)
 687                 fuse_invalidate_entry_cache(entry);
 688
 689         return entry;
 690
 691  out_iput:
 692         iput(inode);
 693  out_err:
 694         return ERR_PTR(err);
 695 }
 696
 697 static int fuse_encode_fh(struct inode *inode, u32 *fh, int *max_len,
 698                            struct inode *parent)
 699 {
 700         int len = parent ? 6 : 3;
 701         u64 nodeid;
 702         u32 generation;
 703
 704         if (*max_len < len) {
 705                 *max_len = len;
 706                 return  FILEID_INVALID;
 707         }
 708
 709         nodeid = get_fuse_inode(inode)->nodeid;
 710         generation = inode->i_generation;
 711
 712         fh[0] = (u32)(nodeid >> 32);
 713         fh[1] = (u32)(nodeid & 0xffffffff);
 714         fh[2] = generation;
 715
 716         if (parent) {
 717                 nodeid = get_fuse_inode(parent)->nodeid;
 718                 generation = parent->i_generation;
 719
 720                 fh[3] = (u32)(nodeid >> 32);
 721                 fh[4] = (u32)(nodeid & 0xffffffff);
 722                 fh[5] = generation;
 723         }
 724
 725         *max_len = len;
 726         return parent ? 0x82 : 0x81;
 727 }
 728
 729 static struct dentry *fuse_fh_to_dentry(struct super_block *sb,
 730                 struct fid *fid, int fh_len, int fh_type)
 731 {
 732         struct fuse_inode_handle handle;
 733
 734         if ((fh_type != 0x81 && fh_type != 0x82) || fh_len < 3)
 735                 return NULL;
 736
 737         handle.nodeid = (u64) fid->raw[0] << 32;
 738         handle.nodeid |= (u64) fid->raw[1];
 739         handle.generation = fid->raw[2];
 740         return fuse_get_dentry(sb, &handle);
 741 }
 742
 743 static struct dentry *fuse_fh_to_parent(struct super_block *sb,
 744                 struct fid *fid, int fh_len, int fh_type)
 745 {
 746         struct fuse_inode_handle parent;
 747
 748         if (fh_type != 0x82 || fh_len < 6)
 749                 return NULL;
 750
 751         parent.nodeid = (u64) fid->raw[3] << 32;
 752         parent.nodeid |= (u64) fid->raw[4];
 753         parent.generation = fid->raw[5];
 754         return fuse_get_dentry(sb, &parent);
 755 }
 756
 757 static struct dentry *fuse_get_parent(struct dentry *child)
 758 {
 759         struct inode *child_inode = d_inode(child);
 760         struct fuse_conn *fc = get_fuse_conn(child_inode);
 761         struct inode *inode;
 762         struct dentry *parent;
 763         struct fuse_entry_out outarg;
 764         struct qstr name;
 765         int err;
 766
 767         if (!fc->export_support)
 768                 return ERR_PTR(-ESTALE);
 769
 770         name.len = 2;
 771         name.name = "..";
 772         err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode),
 773                                &name, &outarg, &inode);
 774         if (err) {
 775                 if (err == -ENOENT)
 776                         return ERR_PTR(-ESTALE);
 777                 return ERR_PTR(err);
 778         }
 779
 780         parent = d_obtain_alias(inode);
 781         if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID)
 782                 fuse_invalidate_entry_cache(parent);
 783
 784         return parent;
 785 }
 786
 787 static const struct export_operations fuse_export_operations = {
 788         .fh_to_dentry   = fuse_fh_to_dentry,
 789         .fh_to_parent   = fuse_fh_to_parent,
 790         .encode_fh      = fuse_encode_fh,
 791         .get_parent     = fuse_get_parent,
 792 };
 793
 794 static const struct super_operations fuse_super_operations = {
 795         .alloc_inode    = fuse_alloc_inode,
 796         .destroy_inode  = fuse_destroy_inode,
 797         .evict_inode    = fuse_evict_inode,
 798         .write_inode    = fuse_write_inode,
 799         .drop_inode     = generic_delete_inode,
 800         .remount_fs     = fuse_remount_fs,
 801         .put_super      = fuse_put_super,
 802         .umount_begin   = fuse_umount_begin,
 803         .statfs         = fuse_statfs,
 804         .show_options   = fuse_show_options,
 805 };
 806
 807 static void sanitize_global_limit(unsigned *limit)
 808 {
 809         if (*limit == 0)
 810                 *limit = ((totalram_pages << PAGE_SHIFT) >> 13) /
 811                          sizeof(struct fuse_req);
 812
 813         if (*limit >= 1 << 16)
 814                 *limit = (1 << 16) - 1;
 815 }
 816
 817 static int set_global_limit(const char *val, struct kernel_param *kp)
 818 {
 819         int rv;
 820
 821         rv = param_set_uint(val, kp);
 822         if (rv)
 823                 return rv;
 824
 825         sanitize_global_limit((unsigned *)kp->arg);
 826
 827         return 0;
 828 }
 829
 830 static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg)
 831 {
 832         int cap_sys_admin = capable(CAP_SYS_ADMIN);
 833
 834         if (arg->minor < 13)
 835                 return;
 836
 837         sanitize_global_limit(&max_user_bgreq);
 838         sanitize_global_limit(&max_user_congthresh);
 839
 840         if (arg->max_background) {
 841                 fc->max_background = arg->max_background;
 842
 843                 if (!cap_sys_admin && fc->max_background > max_user_bgreq)
 844                         fc->max_background = max_user_bgreq;
 845         }
 846         if (arg->congestion_threshold) {
 847                 fc->congestion_threshold = arg->congestion_threshold;
 848
 849                 if (!cap_sys_admin &&
 850                     fc->congestion_threshold > max_user_congthresh)
 851                         fc->congestion_threshold = max_user_congthresh;
 852         }
 853 }
 854
 855 static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
 856 {
 857         struct fuse_init_out *arg = &req->misc.init_out;
 858
 859         if (req->out.h.error || arg->major != FUSE_KERNEL_VERSION)
 860                 fc->conn_error = 1;
 861         else {
 862                 unsigned long ra_pages;
 863
 864                 process_init_limits(fc, arg);
 865
 866                 if (arg->minor >= 6) {
 867                         ra_pages = arg->max_readahead / PAGE_CACHE_SIZE;
 868                         if (arg->flags & FUSE_ASYNC_READ)
 869                                 fc->async_read = 1;
 870                         if (!(arg->flags & FUSE_POSIX_LOCKS))
 871                                 fc->no_lock = 1;
 872                         if (arg->minor >= 17) {
 873                                 if (!(arg->flags & FUSE_FLOCK_LOCKS))
 874                                         fc->no_flock = 1;
 875                         } else {
 876                                 if (!(arg->flags & FUSE_POSIX_LOCKS))
 877                                         fc->no_flock = 1;
 878                         }
 879                         if (arg->flags & FUSE_ATOMIC_O_TRUNC)
 880                                 fc->atomic_o_trunc = 1;
 881                         if (arg->minor >= 9) {
 882                                 /* LOOKUP has dependency on proto version */
 883                                 if (arg->flags & FUSE_EXPORT_SUPPORT)
 884                                         fc->export_support = 1;
 885                         }
 886                         if (arg->flags & FUSE_BIG_WRITES)
 887                                 fc->big_writes = 1;
 888                         if (arg->flags & FUSE_DONT_MASK)
 889                                 fc->dont_mask = 1;
 890                         if (arg->flags & FUSE_AUTO_INVAL_DATA)
 891                                 fc->auto_inval_data = 1;
 892                         if (arg->flags & FUSE_DO_READDIRPLUS) {
 893                                 fc->do_readdirplus = 1;
 894                                 if (arg->flags & FUSE_READDIRPLUS_AUTO)
 895                                         fc->readdirplus_auto = 1;
 896                         }
 897                         if (arg->flags & FUSE_ASYNC_DIO)
 898                                 fc->async_dio = 1;
 899                         if (arg->flags & FUSE_WRITEBACK_CACHE)
 900                                 fc->writeback_cache = 1;
 901                         if (arg->time_gran && arg->time_gran <= 1000000000)
 902                                 fc->sb->s_time_gran = arg->time_gran;
 903                 } else {
 904                         ra_pages = fc->max_read / PAGE_CACHE_SIZE;
 905                         fc->no_lock = 1;
 906                         fc->no_flock = 1;
 907                 }
 908
 909                 fc->bdi.ra_pages = min(fc->bdi.ra_pages, ra_pages);
 910                 fc->minor = arg->minor;
 911                 fc->max_write = arg->minor < 5 ? 4096 : arg->max_write;
 912                 fc->max_write = max_t(unsigned, 4096, fc->max_write);
 913                 fc->conn_init = 1;
 914         }
 915         fuse_set_initialized(fc);
 916         wake_up_all(&fc->blocked_waitq);
 917 }
 918
 919 static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req)
 920 {
 921         struct fuse_init_in *arg = &req->misc.init_in;
 922
 923         arg->major = FUSE_KERNEL_VERSION;
 924         arg->minor = FUSE_KERNEL_MINOR_VERSION;
 925         arg->max_readahead = fc->bdi.ra_pages * PAGE_CACHE_SIZE;
 926         arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC |
 927                 FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK |
 928                 FUSE_SPLICE_WRITE | FUSE_SPLICE_MOVE | FUSE_SPLICE_READ |
 929                 FUSE_FLOCK_LOCKS | FUSE_IOCTL_DIR | FUSE_AUTO_INVAL_DATA |
 930                 FUSE_DO_READDIRPLUS | FUSE_READDIRPLUS_AUTO | FUSE_ASYNC_DIO |
 931                 FUSE_WRITEBACK_CACHE | FUSE_NO_OPEN_SUPPORT;
 932         req->in.h.opcode = FUSE_INIT;
 933         req->in.numargs = 1;
 934         req->in.args[0].size = sizeof(*arg);
 935         req->in.args[0].value = arg;
 936         req->out.numargs = 1;
 937         /* Variable length argument used for backward compatibility
 938            with interface version < 7.5.  Rest of init_out is zeroed
 939            by do_get_request(), so a short reply is not a problem */
 940         req->out.argvar = 1;
 941         req->out.args[0].size = sizeof(struct fuse_init_out);
 942         req->out.args[0].value = &req->misc.init_out;
 943         req->end = process_init_reply;
 944         fuse_request_send_background(fc, req);
 945 }
 946
 947 static void fuse_free_conn(struct fuse_conn *fc)
 948 {
 949         WARN_ON(!list_empty(&fc->devices));
 950         kfree_rcu(fc, rcu);
 951 }
 952
 953 static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
 954 {
 955         int err;
 956
 957         fc->bdi.name = "fuse";
 958         fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
 959         /* fuse does it's own writeback accounting */
 960         fc->bdi.capabilities = BDI_CAP_NO_ACCT_WB | BDI_CAP_STRICTLIMIT;
 961
 962         err = bdi_init(&fc->bdi);
 963         if (err)
 964                 return err;
 965
 966         fc->bdi_initialized = 1;
 967
 968         if (sb->s_bdev) {
 969                 err =  bdi_register(&fc->bdi, NULL, "%u:%u-fuseblk",
 970                                     MAJOR(fc->dev), MINOR(fc->dev));
 971         } else {
 972                 err = bdi_register_dev(&fc->bdi, fc->dev);
 973         }
 974
 975         if (err)
 976                 return err;
 977
 978         /*
 979          * For a single fuse filesystem use max 1% of dirty +
 980          * writeback threshold.
 981          *
 982          * This gives about 1M of write buffer for memory maps on a
 983          * machine with 1G and 10% dirty_ratio, which should be more
 984          * than enough.
 985          *
 986          * Privileged users can raise it by writing to
 987          *
 988          *    /sys/class/bdi/<bdi>/max_ratio
 989          */
 990         bdi_set_max_ratio(&fc->bdi, 1);
 991
 992         return 0;
 993 }
 994
 995 struct fuse_dev *fuse_dev_alloc(struct fuse_conn *fc)
 996 {
 997         struct fuse_dev *fud;
 998
 999         fud = kzalloc(sizeof(struct fuse_dev), GFP_KERNEL);
1000         if (fud) {
1001                 fud->fc = fuse_conn_get(fc);
1002                 fuse_pqueue_init(&fud->pq);
1003
1004                 spin_lock(&fc->lock);
1005                 list_add_tail(&fud->entry, &fc->devices);
1006                 spin_unlock(&fc->lock);
1007         }
1008
1009         return fud;
1010 }
1011 EXPORT_SYMBOL_GPL(fuse_dev_alloc);
1012
1013 void fuse_dev_free(struct fuse_dev *fud)
1014 {
1015         struct fuse_conn *fc = fud->fc;
1016
1017         if (fc) {
1018                 spin_lock(&fc->lock);
1019                 list_del(&fud->entry);
1020                 spin_unlock(&fc->lock);
1021
1022                 fuse_conn_put(fc);
1023         }
1024         kfree(fud);
1025 }
1026 EXPORT_SYMBOL_GPL(fuse_dev_free);
1027
1028 static int fuse_fill_super(struct super_block *sb, void *data, int silent)
1029 {
1030         struct fuse_dev *fud;
1031         struct fuse_conn *fc;
1032         struct inode *root;
1033         struct fuse_mount_data d;
1034         struct file *file;
1035         struct dentry *root_dentry;
1036         struct fuse_req *init_req;
1037         int err;
1038         int is_bdev = sb->s_bdev != NULL;
1039
1040         err = -EINVAL;
1041         if (sb->s_flags & MS_MANDLOCK)
1042                 goto err;
1043
1044         sb->s_flags &= ~(MS_NOSEC | MS_I_VERSION);
1045
1046         if (!parse_fuse_opt(data, &d, is_bdev))
1047                 goto err;
1048
1049         if (is_bdev) {
1050 #ifdef CONFIG_BLOCK
1051                 err = -EINVAL;
1052                 if (!sb_set_blocksize(sb, d.blksize))
1053                         goto err;
1054 #endif
1055         } else {
1056                 sb->s_blocksize = PAGE_CACHE_SIZE;
1057                 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
1058         }
1059         sb->s_magic = FUSE_SUPER_MAGIC;
1060         sb->s_op = &fuse_super_operations;
1061         sb->s_maxbytes = MAX_LFS_FILESIZE;
1062         sb->s_time_gran = 1;
1063         sb->s_export_op = &fuse_export_operations;
1064
1065         file = fget(d.fd);
1066         err = -EINVAL;
1067         if (!file)
1068                 goto err;
1069
1070         if ((file->f_op != &fuse_dev_operations) ||
1071             (file->f_cred->user_ns != &init_user_ns))
1072                 goto err_fput;
1073
1074         fc = kmalloc(sizeof(*fc), GFP_KERNEL);
1075         err = -ENOMEM;
1076         if (!fc)
1077                 goto err_fput;
1078
1079         fuse_conn_init(fc);
1080         fc->release = fuse_free_conn;
1081
1082         fud = fuse_dev_alloc(fc);
1083         if (!fud)
1084                 goto err_put_conn;
1085
1086         fc->dev = sb->s_dev;
1087         fc->sb = sb;
1088         err = fuse_bdi_init(fc, sb);
1089         if (err)
1090                 goto err_dev_free;
1091
1092         sb->s_bdi = &fc->bdi;
1093
1094         /* Handle umasking inside the fuse code */
1095         if (sb->s_flags & MS_POSIXACL)
1096                 fc->dont_mask = 1;
1097         sb->s_flags |= MS_POSIXACL;
1098
1099         fc->flags = d.flags;
1100         fc->user_id = d.user_id;
1101         fc->group_id = d.group_id;
1102         fc->max_read = max_t(unsigned, 4096, d.max_read);
1103
1104         /* Used by get_root_inode() */
1105         sb->s_fs_info = fc;
1106
1107         err = -ENOMEM;
1108         root = fuse_get_root_inode(sb, d.rootmode);
1109         root_dentry = d_make_root(root);
1110         if (!root_dentry)
1111                 goto err_dev_free;
1112         /* only now - we want root dentry with NULL ->d_op */
1113         sb->s_d_op = &fuse_dentry_operations;
1114
1115         init_req = fuse_request_alloc(0);
1116         if (!init_req)
1117                 goto err_put_root;
1118         __set_bit(FR_BACKGROUND, &init_req->flags);
1119
1120         if (is_bdev) {
1121                 fc->destroy_req = fuse_request_alloc(0);
1122                 if (!fc->destroy_req)
1123                         goto err_free_init_req;
1124         }
1125
1126         mutex_lock(&fuse_mutex);
1127         err = -EINVAL;
1128         if (file->private_data)
1129                 goto err_unlock;
1130
1131         err = fuse_ctl_add_conn(fc);
1132         if (err)
1133                 goto err_unlock;
1134
1135         list_add_tail(&fc->entry, &fuse_conn_list);
1136         sb->s_root = root_dentry;
1137         file->private_data = fud;
1138         mutex_unlock(&fuse_mutex);
1139         /*
1140          * atomic_dec_and_test() in fput() provides the necessary
1141          * memory barrier for file->private_data to be visible on all
1142          * CPUs after this
1143          */
1144         fput(file);
1145
1146         fuse_send_init(fc, init_req);
1147
1148         return 0;
1149
1150  err_unlock:
1151         mutex_unlock(&fuse_mutex);
1152  err_free_init_req:
1153         fuse_request_free(init_req);
1154  err_put_root:
1155         dput(root_dentry);
1156  err_dev_free:
1157         fuse_dev_free(fud);
1158  err_put_conn:
1159         fuse_bdi_destroy(fc);
1160         fuse_conn_put(fc);
1161  err_fput:
1162         fput(file);
1163  err:
1164         return err;
1165 }
1166
1167 static struct dentry *fuse_mount(struct file_system_type *fs_type,
1168                        int flags, const char *dev_name,
1169                        void *raw_data)
1170 {
1171         return mount_nodev(fs_type, flags, raw_data, fuse_fill_super);
1172 }
1173
1174 static void fuse_kill_sb_anon(struct super_block *sb)
1175 {
1176         struct fuse_conn *fc = get_fuse_conn_super(sb);
1177
1178         if (fc) {
1179                 down_write(&fc->killsb);
1180                 fc->sb = NULL;
1181                 up_write(&fc->killsb);
1182         }
1183
1184         kill_anon_super(sb);
1185 }
1186
1187 static struct file_system_type fuse_fs_type = {
1188         .owner          = THIS_MODULE,
1189         .name           = "fuse",
1190         .fs_flags       = FS_HAS_SUBTYPE,
1191         .mount          = fuse_mount,
1192         .kill_sb        = fuse_kill_sb_anon,
1193 };
1194 MODULE_ALIAS_FS("fuse");
1195
1196 #ifdef CONFIG_BLOCK
1197 static struct dentry *fuse_mount_blk(struct file_system_type *fs_type,
1198                            int flags, const char *dev_name,
1199                            void *raw_data)
1200 {
1201         return mount_bdev(fs_type, flags, dev_name, raw_data, fuse_fill_super);
1202 }
1203
1204 static void fuse_kill_sb_blk(struct super_block *sb)
1205 {
1206         struct fuse_conn *fc = get_fuse_conn_super(sb);
1207
1208         if (fc) {
1209                 down_write(&fc->killsb);
1210                 fc->sb = NULL;
1211                 up_write(&fc->killsb);
1212         }
1213
1214         kill_block_super(sb);
1215 }
1216
1217 static struct file_system_type fuseblk_fs_type = {
1218         .owner          = THIS_MODULE,
1219         .name           = "fuseblk",
1220         .mount          = fuse_mount_blk,
1221         .kill_sb        = fuse_kill_sb_blk,
1222         .fs_flags       = FS_REQUIRES_DEV | FS_HAS_SUBTYPE,
1223 };
1224 MODULE_ALIAS_FS("fuseblk");
1225
1226 static inline int register_fuseblk(void)
1227 {
1228         return register_filesystem(&fuseblk_fs_type);
1229 }
1230
1231 static inline void unregister_fuseblk(void)
1232 {
1233         unregister_filesystem(&fuseblk_fs_type);
1234 }
1235 #else
1236 static inline int register_fuseblk(void)
1237 {
1238         return 0;
1239 }
1240
1241 static inline void unregister_fuseblk(void)
1242 {
1243 }
1244 #endif
1245
1246 static void fuse_inode_init_once(void *foo)
1247 {
1248         struct inode *inode = foo;
1249
1250         inode_init_once(inode);
1251 }
1252
1253 static int __init fuse_fs_init(void)
1254 {
1255         int err;
1256
1257         fuse_inode_cachep = kmem_cache_create("fuse_inode",
1258                                               sizeof(struct fuse_inode),
1259                                               0, SLAB_HWCACHE_ALIGN,
1260                                               fuse_inode_init_once);
1261         err = -ENOMEM;
1262         if (!fuse_inode_cachep)
1263                 goto out;
1264
1265         err = register_fuseblk();
1266         if (err)
1267                 goto out2;
1268
1269         err = register_filesystem(&fuse_fs_type);
1270         if (err)
1271                 goto out3;
1272
1273         return 0;
1274
1275  out3:
1276         unregister_fuseblk();
1277  out2:
1278         kmem_cache_destroy(fuse_inode_cachep);
1279  out:
1280         return err;
1281 }
1282
1283 static void fuse_fs_cleanup(void)
1284 {
1285         unregister_filesystem(&fuse_fs_type);
1286         unregister_fuseblk();
1287
1288         /*
1289          * Make sure all delayed rcu free inodes are flushed before we
1290          * destroy cache.
1291          */
1292         rcu_barrier();
1293         kmem_cache_destroy(fuse_inode_cachep);
1294 }
1295
1296 static struct kobject *fuse_kobj;
1297
1298 static int fuse_sysfs_init(void)
1299 {
1300         int err;
1301
1302         fuse_kobj = kobject_create_and_add("fuse", fs_kobj);
1303         if (!fuse_kobj) {
1304                 err = -ENOMEM;
1305                 goto out_err;
1306         }
1307
1308         err = sysfs_create_mount_point(fuse_kobj, "connections");
1309         if (err)
1310                 goto out_fuse_unregister;
1311
1312         return 0;
1313
1314  out_fuse_unregister:
1315         kobject_put(fuse_kobj);
1316  out_err:
1317         return err;
1318 }
1319
1320 static void fuse_sysfs_cleanup(void)
1321 {
1322         sysfs_remove_mount_point(fuse_kobj, "connections");
1323         kobject_put(fuse_kobj);
1324 }
1325
1326 static int __init fuse_init(void)
1327 {
1328         int res;
1329
1330         printk(KERN_INFO "fuse init (API version %i.%i)\n",
1331                FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);
1332
1333         INIT_LIST_HEAD(&fuse_conn_list);
1334         res = fuse_fs_init();
1335         if (res)
1336                 goto err;
1337
1338         res = fuse_dev_init();
1339         if (res)
1340                 goto err_fs_cleanup;
1341
1342         res = fuse_sysfs_init();
1343         if (res)
1344                 goto err_dev_cleanup;
1345
1346         res = fuse_ctl_init();
1347         if (res)
1348                 goto err_sysfs_cleanup;
1349
1350         sanitize_global_limit(&max_user_bgreq);
1351         sanitize_global_limit(&max_user_congthresh);
1352
1353         return 0;
1354
1355  err_sysfs_cleanup:
1356         fuse_sysfs_cleanup();
1357  err_dev_cleanup:
1358         fuse_dev_cleanup();
1359  err_fs_cleanup:
1360         fuse_fs_cleanup();
1361  err:
1362         return res;
1363 }
1364
1365 static void __exit fuse_exit(void)
1366 {
1367         printk(KERN_DEBUG "fuse exit\n");
1368
1369         fuse_ctl_cleanup();
1370         fuse_sysfs_cleanup();
1371         fuse_fs_cleanup();
1372         fuse_dev_cleanup();
1373 }
1374
1375 module_init(fuse_init);
1376 module_exit(fuse_exit);