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 #include <linux/posix_acl.h>
  24
  25 MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
  26 MODULE_DESCRIPTION("Filesystem in Userspace");
  27 MODULE_LICENSE("GPL");
  28
  29 static struct kmem_cache *fuse_inode_cachep;
  30 struct list_head fuse_conn_list;
  31 DEFINE_MUTEX(fuse_mutex);
  32
  33 static int set_global_limit(const char *val, struct kernel_param *kp);
  34
  35 unsigned max_user_bgreq;
  36 module_param_call(max_user_bgreq, set_global_limit, param_get_uint,
  37                   &max_user_bgreq, 0644);
  38 __MODULE_PARM_TYPE(max_user_bgreq, "uint");
  39 MODULE_PARM_DESC(max_user_bgreq,
  40  "Global limit for the maximum number of backgrounded requests an "
  41  "unprivileged user can set");
  42
  43 unsigned max_user_congthresh;
  44 module_param_call(max_user_congthresh, set_global_limit, param_get_uint,
  45                   &max_user_congthresh, 0644);
  46 __MODULE_PARM_TYPE(max_user_congthresh, "uint");
  47 MODULE_PARM_DESC(max_user_congthresh,
  48  "Global limit for the maximum congestion threshold an "
  49  "unprivileged user can set");
  50
  51 #define FUSE_SUPER_MAGIC 0x65735546
  52
  53 #define FUSE_DEFAULT_BLKSIZE 512
  54
  55 /** Maximum number of outstanding background requests */
  56 #define FUSE_DEFAULT_MAX_BACKGROUND 12
  57
  58 /** Congestion starts at 75% of maximum */
  59 #define FUSE_DEFAULT_CONGESTION_THRESHOLD (FUSE_DEFAULT_MAX_BACKGROUND * 3 / 4)
  60
  61 struct fuse_mount_data {
  62         int fd;
  63         unsigned rootmode;
  64         kuid_t user_id;
  65         kgid_t group_id;
  66         unsigned fd_present:1;
  67         unsigned rootmode_present:1;
  68         unsigned user_id_present:1;
  69         unsigned group_id_present:1;
  70         unsigned default_permissions:1;
  71         unsigned allow_other:1;
  72         unsigned max_read;
  73         unsigned blksize;
  74 };
  75
  76 struct fuse_forget_link *fuse_alloc_forget(void)
  77 {
  78         return kzalloc(sizeof(struct fuse_forget_link), GFP_KERNEL);
  79 }
  80
  81 static struct inode *fuse_alloc_inode(struct super_block *sb)
  82 {
  83         struct inode *inode;
  84         struct fuse_inode *fi;
  85
  86         inode = kmem_cache_alloc(fuse_inode_cachep, GFP_KERNEL);
  87         if (!inode)
  88                 return NULL;
  89
  90         fi = get_fuse_inode(inode);
  91         fi->i_time = 0;
  92         fi->nodeid = 0;
  93         fi->nlookup = 0;
  94         fi->attr_version = 0;
  95         fi->writectr = 0;
  96         fi->orig_ino = 0;
  97         fi->state = 0;
  98         INIT_LIST_HEAD(&fi->write_files);
  99         INIT_LIST_HEAD(&fi->queued_writes);
 100         INIT_LIST_HEAD(&fi->writepages);
 101         init_waitqueue_head(&fi->page_waitq);
 102         mutex_init(&fi->mutex);
 103         fi->forget = fuse_alloc_forget();
 104         if (!fi->forget) {
 105                 kmem_cache_free(fuse_inode_cachep, inode);
 106                 return NULL;
 107         }
 108
 109         return inode;
 110 }
 111
 112 static void fuse_i_callback(struct rcu_head *head)
 113 {
 114         struct inode *inode = container_of(head, struct inode, i_rcu);
 115         kmem_cache_free(fuse_inode_cachep, inode);
 116 }
 117
 118 static void fuse_destroy_inode(struct inode *inode)
 119 {
 120         struct fuse_inode *fi = get_fuse_inode(inode);
 121         BUG_ON(!list_empty(&fi->write_files));
 122         BUG_ON(!list_empty(&fi->queued_writes));
 123         mutex_destroy(&fi->mutex);
 124         kfree(fi->forget);
 125         call_rcu(&inode->i_rcu, fuse_i_callback);
 126 }
 127
 128 static void fuse_evict_inode(struct inode *inode)
 129 {
 130         truncate_inode_pages_final(&inode->i_data);
 131         clear_inode(inode);
 132         if (inode->i_sb->s_flags & MS_ACTIVE) {
 133                 struct fuse_conn *fc = get_fuse_conn(inode);
 134                 struct fuse_inode *fi = get_fuse_inode(inode);
 135                 fuse_queue_forget(fc, fi->forget, fi->nodeid, fi->nlookup);
 136                 fi->forget = NULL;
 137         }
 138 }
 139
 140 static int fuse_remount_fs(struct super_block *sb, int *flags, char *data)
 141 {
 142         sync_filesystem(sb);
 143         if (*flags & MS_MANDLOCK)
 144                 return -EINVAL;
 145
 146         return 0;
 147 }
 148
 149 /*
 150  * ino_t is 32-bits on 32-bit arch. We have to squash the 64-bit value down
 151  * so that it will fit.
 152  */
 153 static ino_t fuse_squash_ino(u64 ino64)
 154 {
 155         ino_t ino = (ino_t) ino64;
 156         if (sizeof(ino_t) < sizeof(u64))
 157                 ino ^= ino64 >> (sizeof(u64) - sizeof(ino_t)) * 8;
 158         return ino;
 159 }
 160
 161 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
 162                                    u64 attr_valid)
 163 {
 164         struct fuse_conn *fc = get_fuse_conn(inode);
 165         struct fuse_inode *fi = get_fuse_inode(inode);
 166
 167         fi->attr_version = ++fc->attr_version;
 168         fi->i_time = attr_valid;
 169
 170         inode->i_ino     = fuse_squash_ino(attr->ino);
 171         inode->i_mode    = (inode->i_mode & S_IFMT) | (attr->mode & 07777);
 172         set_nlink(inode, attr->nlink);
 173         inode->i_uid     = make_kuid(&init_user_ns, attr->uid);
 174         inode->i_gid     = make_kgid(&init_user_ns, attr->gid);
 175         inode->i_blocks  = attr->blocks;
 176         inode->i_atime.tv_sec   = attr->atime;
 177         inode->i_atime.tv_nsec  = attr->atimensec;
 178         /* mtime from server may be stale due to local buffered write */
 179         if (!fc->writeback_cache || !S_ISREG(inode->i_mode)) {
 180                 inode->i_mtime.tv_sec   = attr->mtime;
 181                 inode->i_mtime.tv_nsec  = attr->mtimensec;
 182                 inode->i_ctime.tv_sec   = attr->ctime;
 183                 inode->i_ctime.tv_nsec  = attr->ctimensec;
 184         }
 185
 186         if (attr->blksize != 0)
 187                 inode->i_blkbits = ilog2(attr->blksize);
 188         else
 189                 inode->i_blkbits = inode->i_sb->s_blocksize_bits;
 190
 191         /*
 192          * Don't set the sticky bit in i_mode, unless we want the VFS
 193          * to check permissions.  This prevents failures due to the
 194          * check in may_delete().
 195          */
 196         fi->orig_i_mode = inode->i_mode;
 197         if (!fc->default_permissions)
 198                 inode->i_mode &= ~S_ISVTX;
 199
 200         fi->orig_ino = attr->ino;
 201 }
 202
 203 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
 204                             u64 attr_valid, u64 attr_version)
 205 {
 206         struct fuse_conn *fc = get_fuse_conn(inode);
 207         struct fuse_inode *fi = get_fuse_inode(inode);
 208         bool is_wb = fc->writeback_cache;
 209         loff_t oldsize;
 210         struct timespec old_mtime;
 211
 212         spin_lock(&fc->lock);
 213         if ((attr_version != 0 && fi->attr_version > attr_version) ||
 214             test_bit(FUSE_I_SIZE_UNSTABLE, &fi->state)) {
 215                 spin_unlock(&fc->lock);
 216                 return;
 217         }
 218
 219         old_mtime = inode->i_mtime;
 220         fuse_change_attributes_common(inode, attr, attr_valid);
 221
 222         oldsize = inode->i_size;
 223         /*
 224          * In case of writeback_cache enabled, the cached writes beyond EOF
 225          * extend local i_size without keeping userspace server in sync. So,
 226          * attr->size coming from server can be stale. We cannot trust it.
 227          */
 228         if (!is_wb || !S_ISREG(inode->i_mode))
 229                 i_size_write(inode, attr->size);
 230         spin_unlock(&fc->lock);
 231
 232         if (!is_wb && S_ISREG(inode->i_mode)) {
 233                 bool inval = false;
 234
 235                 if (oldsize != attr->size) {
 236                         truncate_pagecache(inode, attr->size);
 237                         inval = true;
 238                 } else if (fc->auto_inval_data) {
 239                         struct timespec new_mtime = {
 240                                 .tv_sec = attr->mtime,
 241                                 .tv_nsec = attr->mtimensec,
 242                         };
 243
 244                         /*
 245                          * Auto inval mode also checks and invalidates if mtime
 246                          * has changed.
 247                          */
 248                         if (!timespec_equal(&old_mtime, &new_mtime))
 249                                 inval = true;
 250                 }
 251
 252                 if (inval)
 253                         invalidate_inode_pages2(inode->i_mapping);
 254         }
 255 }
 256
 257 static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr)
 258 {
 259         inode->i_mode = attr->mode & S_IFMT;
 260         inode->i_size = attr->size;
 261         inode->i_mtime.tv_sec  = attr->mtime;
 262         inode->i_mtime.tv_nsec = attr->mtimensec;
 263         inode->i_ctime.tv_sec  = attr->ctime;
 264         inode->i_ctime.tv_nsec = attr->ctimensec;
 265         if (S_ISREG(inode->i_mode)) {
 266                 fuse_init_common(inode);
 267                 fuse_init_file_inode(inode);
 268         } else if (S_ISDIR(inode->i_mode))
 269                 fuse_init_dir(inode);
 270         else if (S_ISLNK(inode->i_mode))
 271                 fuse_init_symlink(inode);
 272         else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
 273                  S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
 274                 fuse_init_common(inode);
 275                 init_special_inode(inode, inode->i_mode,
 276                                    new_decode_dev(attr->rdev));
 277         } else
 278                 BUG();
 279 }
 280
 281 int fuse_inode_eq(struct inode *inode, void *_nodeidp)
 282 {
 283         u64 nodeid = *(u64 *) _nodeidp;
 284         if (get_node_id(inode) == nodeid)
 285                 return 1;
 286         else
 287                 return 0;
 288 }
 289
 290 static int fuse_inode_set(struct inode *inode, void *_nodeidp)
 291 {
 292         u64 nodeid = *(u64 *) _nodeidp;
 293         get_fuse_inode(inode)->nodeid = nodeid;
 294         return 0;
 295 }
 296
 297 struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
 298                         int generation, struct fuse_attr *attr,
 299                         u64 attr_valid, u64 attr_version)
 300 {
 301         struct inode *inode;
 302         struct fuse_inode *fi;
 303         struct fuse_conn *fc = get_fuse_conn_super(sb);
 304
 305  retry:
 306         inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid);
 307         if (!inode)
 308                 return NULL;
 309
 310         if ((inode->i_state & I_NEW)) {
 311                 inode->i_flags |= S_NOATIME;
 312                 if (!fc->writeback_cache || !S_ISREG(attr->mode))
 313                         inode->i_flags |= S_NOCMTIME;
 314                 inode->i_generation = generation;
 315                 fuse_init_inode(inode, attr);
 316                 unlock_new_inode(inode);
 317         } else if ((inode->i_mode ^ attr->mode) & S_IFMT) {
 318                 /* Inode has changed type, any I/O on the old should fail */
 319                 make_bad_inode(inode);
 320                 iput(inode);
 321                 goto retry;
 322         }
 323
 324         fi = get_fuse_inode(inode);
 325         spin_lock(&fc->lock);
 326         fi->nlookup++;
 327         spin_unlock(&fc->lock);
 328         fuse_change_attributes(inode, attr, attr_valid, attr_version);
 329
 330         return inode;
 331 }
 332
 333 int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid,
 334                              loff_t offset, loff_t len)
 335 {
 336         struct inode *inode;
 337         pgoff_t pg_start;
 338         pgoff_t pg_end;
 339
 340         inode = ilookup5(sb, nodeid, fuse_inode_eq, &nodeid);
 341         if (!inode)
 342                 return -ENOENT;
 343
 344         fuse_invalidate_attr(inode);
 345         forget_all_cached_acls(inode);
 346         if (offset >= 0) {
 347                 pg_start = offset >> PAGE_SHIFT;
 348                 if (len <= 0)
 349                         pg_end = -1;
 350                 else
 351                         pg_end = (offset + len - 1) >> PAGE_SHIFT;
 352                 invalidate_inode_pages2_range(inode->i_mapping,
 353                                               pg_start, pg_end);
 354         }
 355         iput(inode);
 356         return 0;
 357 }
 358
 359 void fuse_lock_inode(struct inode *inode)
 360 {
 361         if (!get_fuse_conn(inode)->parallel_dirops)
 362                 mutex_lock(&get_fuse_inode(inode)->mutex);
 363 }
 364
 365 void fuse_unlock_inode(struct inode *inode)
 366 {
 367         if (!get_fuse_conn(inode)->parallel_dirops)
 368                 mutex_unlock(&get_fuse_inode(inode)->mutex);
 369 }
 370
 371 static void fuse_umount_begin(struct super_block *sb)
 372 {
 373         fuse_abort_conn(get_fuse_conn_super(sb));
 374 }
 375
 376 static void fuse_send_destroy(struct fuse_conn *fc)
 377 {
 378         struct fuse_req *req = fc->destroy_req;
 379         if (req && fc->conn_init) {
 380                 fc->destroy_req = NULL;
 381                 req->in.h.opcode = FUSE_DESTROY;
 382                 __set_bit(FR_FORCE, &req->flags);
 383                 __clear_bit(FR_BACKGROUND, &req->flags);
 384                 fuse_request_send(fc, req);
 385                 fuse_put_request(fc, req);
 386         }
 387 }
 388
 389 static void fuse_bdi_destroy(struct fuse_conn *fc)
 390 {
 391         if (fc->bdi_initialized)
 392                 bdi_destroy(&fc->bdi);
 393 }
 394
 395 static void fuse_put_super(struct super_block *sb)
 396 {
 397         struct fuse_conn *fc = get_fuse_conn_super(sb);
 398
 399         fuse_send_destroy(fc);
 400
 401         fuse_abort_conn(fc);
 402         mutex_lock(&fuse_mutex);
 403         list_del(&fc->entry);
 404         fuse_ctl_remove_conn(fc);
 405         mutex_unlock(&fuse_mutex);
 406         fuse_bdi_destroy(fc);
 407
 408         fuse_conn_put(fc);
 409 }
 410
 411 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr)
 412 {
 413         stbuf->f_type    = FUSE_SUPER_MAGIC;
 414         stbuf->f_bsize   = attr->bsize;
 415         stbuf->f_frsize  = attr->frsize;
 416         stbuf->f_blocks  = attr->blocks;
 417         stbuf->f_bfree   = attr->bfree;
 418         stbuf->f_bavail  = attr->bavail;
 419         stbuf->f_files   = attr->files;
 420         stbuf->f_ffree   = attr->ffree;
 421         stbuf->f_namelen = attr->namelen;
 422         /* fsid is left zero */
 423 }
 424
 425 static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf)
 426 {
 427         struct super_block *sb = dentry->d_sb;
 428         struct fuse_conn *fc = get_fuse_conn_super(sb);
 429         FUSE_ARGS(args);
 430         struct fuse_statfs_out outarg;
 431         int err;
 432
 433         if (!fuse_allow_current_process(fc)) {
 434                 buf->f_type = FUSE_SUPER_MAGIC;
 435                 return 0;
 436         }
 437
 438         memset(&outarg, 0, sizeof(outarg));
 439         args.in.numargs = 0;
 440         args.in.h.opcode = FUSE_STATFS;
 441         args.in.h.nodeid = get_node_id(d_inode(dentry));
 442         args.out.numargs = 1;
 443         args.out.args[0].size = sizeof(outarg);
 444         args.out.args[0].value = &outarg;
 445         err = fuse_simple_request(fc, &args);
 446         if (!err)
 447                 convert_fuse_statfs(buf, &outarg.st);
 448         return err;
 449 }
 450
 451 enum {
 452         OPT_FD,
 453         OPT_ROOTMODE,
 454         OPT_USER_ID,
 455         OPT_GROUP_ID,
 456         OPT_DEFAULT_PERMISSIONS,
 457         OPT_ALLOW_OTHER,
 458         OPT_MAX_READ,
 459         OPT_BLKSIZE,
 460         OPT_ERR
 461 };
 462
 463 static const match_table_t tokens = {
 464         {OPT_FD,                        "fd=%u"},
 465         {OPT_ROOTMODE,                  "rootmode=%o"},
 466         {OPT_USER_ID,                   "user_id=%u"},
 467         {OPT_GROUP_ID,                  "group_id=%u"},
 468         {OPT_DEFAULT_PERMISSIONS,       "default_permissions"},
 469         {OPT_ALLOW_OTHER,               "allow_other"},
 470         {OPT_MAX_READ,                  "max_read=%u"},
 471         {OPT_BLKSIZE,                   "blksize=%u"},
 472         {OPT_ERR,                       NULL}
 473 };
 474
 475 static int fuse_match_uint(substring_t *s, unsigned int *res)
 476 {
 477         int err = -ENOMEM;
 478         char *buf = match_strdup(s);
 479         if (buf) {
 480                 err = kstrtouint(buf, 10, res);
 481                 kfree(buf);
 482         }
 483         return err;
 484 }
 485
 486 static int parse_fuse_opt(char *opt, struct fuse_mount_data *d, int is_bdev)
 487 {
 488         char *p;
 489         memset(d, 0, sizeof(struct fuse_mount_data));
 490         d->max_read = ~0;
 491         d->blksize = FUSE_DEFAULT_BLKSIZE;
 492
 493         while ((p = strsep(&opt, ",")) != NULL) {
 494                 int token;
 495                 int value;
 496                 unsigned uv;
 497                 substring_t args[MAX_OPT_ARGS];
 498                 if (!*p)
 499                         continue;
 500
 501                 token = match_token(p, tokens, args);
 502                 switch (token) {
 503                 case OPT_FD:
 504                         if (match_int(&args[0], &value))
 505                                 return 0;
 506                         d->fd = value;
 507                         d->fd_present = 1;
 508                         break;
 509
 510                 case OPT_ROOTMODE:
 511                         if (match_octal(&args[0], &value))
 512                                 return 0;
 513                         if (!fuse_valid_type(value))
 514                                 return 0;
 515                         d->rootmode = value;
 516                         d->rootmode_present = 1;
 517                         break;
 518
 519                 case OPT_USER_ID:
 520                         if (fuse_match_uint(&args[0], &uv))
 521                                 return 0;
 522                         d->user_id = make_kuid(current_user_ns(), uv);
 523                         if (!uid_valid(d->user_id))
 524                                 return 0;
 525                         d->user_id_present = 1;
 526                         break;
 527
 528                 case OPT_GROUP_ID:
 529                         if (fuse_match_uint(&args[0], &uv))
 530                                 return 0;
 531                         d->group_id = make_kgid(current_user_ns(), uv);
 532                         if (!gid_valid(d->group_id))
 533                                 return 0;
 534                         d->group_id_present = 1;
 535                         break;
 536
 537                 case OPT_DEFAULT_PERMISSIONS:
 538                         d->default_permissions = 1;
 539                         break;
 540
 541                 case OPT_ALLOW_OTHER:
 542                         d->allow_other = 1;
 543                         break;
 544
 545                 case OPT_MAX_READ:
 546                         if (match_int(&args[0], &value))
 547                                 return 0;
 548                         d->max_read = value;
 549                         break;
 550
 551                 case OPT_BLKSIZE:
 552                         if (!is_bdev || match_int(&args[0], &value))
 553                                 return 0;
 554                         d->blksize = value;
 555                         break;
 556
 557                 default:
 558                         return 0;
 559                 }
 560         }
 561
 562         if (!d->fd_present || !d->rootmode_present ||
 563             !d->user_id_present || !d->group_id_present)
 564                 return 0;
 565
 566         return 1;
 567 }
 568
 569 static int fuse_show_options(struct seq_file *m, struct dentry *root)
 570 {
 571         struct super_block *sb = root->d_sb;
 572         struct fuse_conn *fc = get_fuse_conn_super(sb);
 573
 574         seq_printf(m, ",user_id=%u", from_kuid_munged(&init_user_ns, fc->user_id));
 575         seq_printf(m, ",group_id=%u", from_kgid_munged(&init_user_ns, fc->group_id));
 576         if (fc->default_permissions)
 577                 seq_puts(m, ",default_permissions");
 578         if (fc->allow_other)
 579                 seq_puts(m, ",allow_other");
 580         if (fc->max_read != ~0)
 581                 seq_printf(m, ",max_read=%u", fc->max_read);
 582         if (sb->s_bdev && sb->s_blocksize != FUSE_DEFAULT_BLKSIZE)
 583                 seq_printf(m, ",blksize=%lu", sb->s_blocksize);
 584         return 0;
 585 }
 586
 587 static void fuse_iqueue_init(struct fuse_iqueue *fiq)
 588 {
 589         memset(fiq, 0, sizeof(struct fuse_iqueue));
 590         init_waitqueue_head(&fiq->waitq);
 591         INIT_LIST_HEAD(&fiq->pending);
 592         INIT_LIST_HEAD(&fiq->interrupts);
 593         fiq->forget_list_tail = &fiq->forget_list_head;
 594         fiq->connected = 1;
 595 }
 596
 597 static void fuse_pqueue_init(struct fuse_pqueue *fpq)
 598 {
 599         memset(fpq, 0, sizeof(struct fuse_pqueue));
 600         spin_lock_init(&fpq->lock);
 601         INIT_LIST_HEAD(&fpq->processing);
 602         INIT_LIST_HEAD(&fpq->io);
 603         fpq->connected = 1;
 604 }
 605
 606 void fuse_conn_init(struct fuse_conn *fc)
 607 {
 608         memset(fc, 0, sizeof(*fc));
 609         spin_lock_init(&fc->lock);
 610         init_rwsem(&fc->killsb);
 611         atomic_set(&fc->count, 1);
 612         atomic_set(&fc->dev_count, 1);
 613         init_waitqueue_head(&fc->blocked_waitq);
 614         init_waitqueue_head(&fc->reserved_req_waitq);
 615         fuse_iqueue_init(&fc->iq);
 616         INIT_LIST_HEAD(&fc->bg_queue);
 617         INIT_LIST_HEAD(&fc->entry);
 618         INIT_LIST_HEAD(&fc->devices);
 619         atomic_set(&fc->num_waiting, 0);
 620         fc->max_background = FUSE_DEFAULT_MAX_BACKGROUND;
 621         fc->congestion_threshold = FUSE_DEFAULT_CONGESTION_THRESHOLD;
 622         fc->khctr = 0;
 623         fc->polled_files = RB_ROOT;
 624         fc->blocked = 0;
 625         fc->initialized = 0;
 626         fc->connected = 1;
 627         fc->attr_version = 1;
 628         get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key));
 629 }
 630 EXPORT_SYMBOL_GPL(fuse_conn_init);
 631
 632 void fuse_conn_put(struct fuse_conn *fc)
 633 {
 634         if (atomic_dec_and_test(&fc->count)) {
 635                 if (fc->destroy_req)
 636                         fuse_request_free(fc->destroy_req);
 637                 fc->release(fc);
 638         }
 639 }
 640 EXPORT_SYMBOL_GPL(fuse_conn_put);
 641
 642 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc)
 643 {
 644         atomic_inc(&fc->count);
 645         return fc;
 646 }
 647 EXPORT_SYMBOL_GPL(fuse_conn_get);
 648
 649 static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned mode)
 650 {
 651         struct fuse_attr attr;
 652         memset(&attr, 0, sizeof(attr));
 653
 654         attr.mode = mode;
 655         attr.ino = FUSE_ROOT_ID;
 656         attr.nlink = 1;
 657         return fuse_iget(sb, 1, 0, &attr, 0, 0);
 658 }
 659
 660 struct fuse_inode_handle {
 661         u64 nodeid;
 662         u32 generation;
 663 };
 664
 665 static struct dentry *fuse_get_dentry(struct super_block *sb,
 666                                       struct fuse_inode_handle *handle)
 667 {
 668         struct fuse_conn *fc = get_fuse_conn_super(sb);
 669         struct inode *inode;
 670         struct dentry *entry;
 671         int err = -ESTALE;
 672
 673         if (handle->nodeid == 0)
 674                 goto out_err;
 675
 676         inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid);
 677         if (!inode) {
 678                 struct fuse_entry_out outarg;
 679                 const struct qstr name = QSTR_INIT(".", 1);
 680
 681                 if (!fc->export_support)
 682                         goto out_err;
 683
 684                 err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg,
 685                                        &inode);
 686                 if (err && err != -ENOENT)
 687                         goto out_err;
 688                 if (err || !inode) {
 689                         err = -ESTALE;
 690                         goto out_err;
 691                 }
 692                 err = -EIO;
 693                 if (get_node_id(inode) != handle->nodeid)
 694                         goto out_iput;
 695         }
 696         err = -ESTALE;
 697         if (inode->i_generation != handle->generation)
 698                 goto out_iput;
 699
 700         entry = d_obtain_alias(inode);
 701         if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID)
 702                 fuse_invalidate_entry_cache(entry);
 703
 704         return entry;
 705
 706  out_iput:
 707         iput(inode);
 708  out_err:
 709         return ERR_PTR(err);
 710 }
 711
 712 static int fuse_encode_fh(struct inode *inode, u32 *fh, int *max_len,
 713                            struct inode *parent)
 714 {
 715         int len = parent ? 6 : 3;
 716         u64 nodeid;
 717         u32 generation;
 718
 719         if (*max_len < len) {
 720                 *max_len = len;
 721                 return  FILEID_INVALID;
 722         }
 723
 724         nodeid = get_fuse_inode(inode)->nodeid;
 725         generation = inode->i_generation;
 726
 727         fh[0] = (u32)(nodeid >> 32);
 728         fh[1] = (u32)(nodeid & 0xffffffff);
 729         fh[2] = generation;
 730
 731         if (parent) {
 732                 nodeid = get_fuse_inode(parent)->nodeid;
 733                 generation = parent->i_generation;
 734
 735                 fh[3] = (u32)(nodeid >> 32);
 736                 fh[4] = (u32)(nodeid & 0xffffffff);
 737                 fh[5] = generation;
 738         }
 739
 740         *max_len = len;
 741         return parent ? 0x82 : 0x81;
 742 }
 743
 744 static struct dentry *fuse_fh_to_dentry(struct super_block *sb,
 745                 struct fid *fid, int fh_len, int fh_type)
 746 {
 747         struct fuse_inode_handle handle;
 748
 749         if ((fh_type != 0x81 && fh_type != 0x82) || fh_len < 3)
 750                 return NULL;
 751
 752         handle.nodeid = (u64) fid->raw[0] << 32;
 753         handle.nodeid |= (u64) fid->raw[1];
 754         handle.generation = fid->raw[2];
 755         return fuse_get_dentry(sb, &handle);
 756 }
 757
 758 static struct dentry *fuse_fh_to_parent(struct super_block *sb,
 759                 struct fid *fid, int fh_len, int fh_type)
 760 {
 761         struct fuse_inode_handle parent;
 762
 763         if (fh_type != 0x82 || fh_len < 6)
 764                 return NULL;
 765
 766         parent.nodeid = (u64) fid->raw[3] << 32;
 767         parent.nodeid |= (u64) fid->raw[4];
 768         parent.generation = fid->raw[5];
 769         return fuse_get_dentry(sb, &parent);
 770 }
 771
 772 static struct dentry *fuse_get_parent(struct dentry *child)
 773 {
 774         struct inode *child_inode = d_inode(child);
 775         struct fuse_conn *fc = get_fuse_conn(child_inode);
 776         struct inode *inode;
 777         struct dentry *parent;
 778         struct fuse_entry_out outarg;
 779         const struct qstr name = QSTR_INIT("..", 2);
 780         int err;
 781
 782         if (!fc->export_support)
 783                 return ERR_PTR(-ESTALE);
 784
 785         err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode),
 786                                &name, &outarg, &inode);
 787         if (err) {
 788                 if (err == -ENOENT)
 789                         return ERR_PTR(-ESTALE);
 790                 return ERR_PTR(err);
 791         }
 792
 793         parent = d_obtain_alias(inode);
 794         if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID)
 795                 fuse_invalidate_entry_cache(parent);
 796
 797         return parent;
 798 }
 799
 800 static const struct export_operations fuse_export_operations = {
 801         .fh_to_dentry   = fuse_fh_to_dentry,
 802         .fh_to_parent   = fuse_fh_to_parent,
 803         .encode_fh      = fuse_encode_fh,
 804         .get_parent     = fuse_get_parent,
 805 };
 806
 807 static const struct super_operations fuse_super_operations = {
 808         .alloc_inode    = fuse_alloc_inode,
 809         .destroy_inode  = fuse_destroy_inode,
 810         .evict_inode    = fuse_evict_inode,
 811         .write_inode    = fuse_write_inode,
 812         .drop_inode     = generic_delete_inode,
 813         .remount_fs     = fuse_remount_fs,
 814         .put_super      = fuse_put_super,
 815         .umount_begin   = fuse_umount_begin,
 816         .statfs         = fuse_statfs,
 817         .show_options   = fuse_show_options,
 818 };
 819
 820 static void sanitize_global_limit(unsigned *limit)
 821 {
 822         if (*limit == 0)
 823                 *limit = ((totalram_pages << PAGE_SHIFT) >> 13) /
 824                          sizeof(struct fuse_req);
 825
 826         if (*limit >= 1 << 16)
 827                 *limit = (1 << 16) - 1;
 828 }
 829
 830 static int set_global_limit(const char *val, struct kernel_param *kp)
 831 {
 832         int rv;
 833
 834         rv = param_set_uint(val, kp);
 835         if (rv)
 836                 return rv;
 837
 838         sanitize_global_limit((unsigned *)kp->arg);
 839
 840         return 0;
 841 }
 842
 843 static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg)
 844 {
 845         int cap_sys_admin = capable(CAP_SYS_ADMIN);
 846
 847         if (arg->minor < 13)
 848                 return;
 849
 850         sanitize_global_limit(&max_user_bgreq);
 851         sanitize_global_limit(&max_user_congthresh);
 852
 853         if (arg->max_background) {
 854                 fc->max_background = arg->max_background;
 855
 856                 if (!cap_sys_admin && fc->max_background > max_user_bgreq)
 857                         fc->max_background = max_user_bgreq;
 858         }
 859         if (arg->congestion_threshold) {
 860                 fc->congestion_threshold = arg->congestion_threshold;
 861
 862                 if (!cap_sys_admin &&
 863                     fc->congestion_threshold > max_user_congthresh)
 864                         fc->congestion_threshold = max_user_congthresh;
 865         }
 866 }
 867
 868 static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
 869 {
 870         struct fuse_init_out *arg = &req->misc.init_out;
 871
 872         if (req->out.h.error || arg->major != FUSE_KERNEL_VERSION)
 873                 fc->conn_error = 1;
 874         else {
 875                 unsigned long ra_pages;
 876
 877                 process_init_limits(fc, arg);
 878
 879                 if (arg->minor >= 6) {
 880                         ra_pages = arg->max_readahead / PAGE_SIZE;
 881                         if (arg->flags & FUSE_ASYNC_READ)
 882                                 fc->async_read = 1;
 883                         if (!(arg->flags & FUSE_POSIX_LOCKS))
 884                                 fc->no_lock = 1;
 885                         if (arg->minor >= 17) {
 886                                 if (!(arg->flags & FUSE_FLOCK_LOCKS))
 887                                         fc->no_flock = 1;
 888                         } else {
 889                                 if (!(arg->flags & FUSE_POSIX_LOCKS))
 890                                         fc->no_flock = 1;
 891                         }
 892                         if (arg->flags & FUSE_ATOMIC_O_TRUNC)
 893                                 fc->atomic_o_trunc = 1;
 894                         if (arg->minor >= 9) {
 895                                 /* LOOKUP has dependency on proto version */
 896                                 if (arg->flags & FUSE_EXPORT_SUPPORT)
 897                                         fc->export_support = 1;
 898                         }
 899                         if (arg->flags & FUSE_BIG_WRITES)
 900                                 fc->big_writes = 1;
 901                         if (arg->flags & FUSE_DONT_MASK)
 902                                 fc->dont_mask = 1;
 903                         if (arg->flags & FUSE_AUTO_INVAL_DATA)
 904                                 fc->auto_inval_data = 1;
 905                         if (arg->flags & FUSE_DO_READDIRPLUS) {
 906                                 fc->do_readdirplus = 1;
 907                                 if (arg->flags & FUSE_READDIRPLUS_AUTO)
 908                                         fc->readdirplus_auto = 1;
 909                         }
 910                         if (arg->flags & FUSE_ASYNC_DIO)
 911                                 fc->async_dio = 1;
 912                         if (arg->flags & FUSE_WRITEBACK_CACHE)
 913                                 fc->writeback_cache = 1;
 914                         if (arg->flags & FUSE_PARALLEL_DIROPS)
 915                                 fc->parallel_dirops = 1;
 916                         if (arg->flags & FUSE_HANDLE_KILLPRIV)
 917                                 fc->handle_killpriv = 1;
 918                         if (arg->time_gran && arg->time_gran <= 1000000000)
 919                                 fc->sb->s_time_gran = arg->time_gran;
 920                         if ((arg->flags & FUSE_POSIX_ACL)) {
 921                                 fc->default_permissions = 1;
 922                                 fc->posix_acl = 1;
 923                                 fc->sb->s_xattr = fuse_acl_xattr_handlers;
 924                         }
 925                 } else {
 926                         ra_pages = fc->max_read / PAGE_SIZE;
 927                         fc->no_lock = 1;
 928                         fc->no_flock = 1;
 929                 }
 930
 931                 fc->bdi.ra_pages = min(fc->bdi.ra_pages, ra_pages);
 932                 fc->minor = arg->minor;
 933                 fc->max_write = arg->minor < 5 ? 4096 : arg->max_write;
 934                 fc->max_write = max_t(unsigned, 4096, fc->max_write);
 935                 fc->conn_init = 1;
 936         }
 937         fuse_set_initialized(fc);
 938         wake_up_all(&fc->blocked_waitq);
 939 }
 940
 941 static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req)
 942 {
 943         struct fuse_init_in *arg = &req->misc.init_in;
 944
 945         arg->major = FUSE_KERNEL_VERSION;
 946         arg->minor = FUSE_KERNEL_MINOR_VERSION;
 947         arg->max_readahead = fc->bdi.ra_pages * PAGE_SIZE;
 948         arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC |
 949                 FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK |
 950                 FUSE_SPLICE_WRITE | FUSE_SPLICE_MOVE | FUSE_SPLICE_READ |
 951                 FUSE_FLOCK_LOCKS | FUSE_HAS_IOCTL_DIR | FUSE_AUTO_INVAL_DATA |
 952                 FUSE_DO_READDIRPLUS | FUSE_READDIRPLUS_AUTO | FUSE_ASYNC_DIO |
 953                 FUSE_WRITEBACK_CACHE | FUSE_NO_OPEN_SUPPORT |
 954                 FUSE_PARALLEL_DIROPS | FUSE_HANDLE_KILLPRIV | FUSE_POSIX_ACL;
 955         req->in.h.opcode = FUSE_INIT;
 956         req->in.numargs = 1;
 957         req->in.args[0].size = sizeof(*arg);
 958         req->in.args[0].value = arg;
 959         req->out.numargs = 1;
 960         /* Variable length argument used for backward compatibility
 961            with interface version < 7.5.  Rest of init_out is zeroed
 962            by do_get_request(), so a short reply is not a problem */
 963         req->out.argvar = 1;
 964         req->out.args[0].size = sizeof(struct fuse_init_out);
 965         req->out.args[0].value = &req->misc.init_out;
 966         req->end = process_init_reply;
 967         fuse_request_send_background(fc, req);
 968 }
 969
 970 static void fuse_free_conn(struct fuse_conn *fc)
 971 {
 972         WARN_ON(!list_empty(&fc->devices));
 973         kfree_rcu(fc, rcu);
 974 }
 975
 976 static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
 977 {
 978         int err;
 979
 980         fc->bdi.name = "fuse";
 981         fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_SIZE;
 982         /* fuse does it's own writeback accounting */
 983         fc->bdi.capabilities = BDI_CAP_NO_ACCT_WB | BDI_CAP_STRICTLIMIT;
 984
 985         err = bdi_init(&fc->bdi);
 986         if (err)
 987                 return err;
 988
 989         fc->bdi_initialized = 1;
 990
 991         if (sb->s_bdev) {
 992                 err =  bdi_register(&fc->bdi, NULL, "%u:%u-fuseblk",
 993                                     MAJOR(fc->dev), MINOR(fc->dev));
 994         } else {
 995                 err = bdi_register_dev(&fc->bdi, fc->dev);
 996         }
 997
 998         if (err)
 999                 return err;
1000
1001         /*
1002          * For a single fuse filesystem use max 1% of dirty +
1003          * writeback threshold.
1004          *
1005          * This gives about 1M of write buffer for memory maps on a
1006          * machine with 1G and 10% dirty_ratio, which should be more
1007          * than enough.
1008          *
1009          * Privileged users can raise it by writing to
1010          *
1011          *    /sys/class/bdi/<bdi>/max_ratio
1012          */
1013         bdi_set_max_ratio(&fc->bdi, 1);
1014
1015         return 0;
1016 }
1017
1018 struct fuse_dev *fuse_dev_alloc(struct fuse_conn *fc)
1019 {
1020         struct fuse_dev *fud;
1021
1022         fud = kzalloc(sizeof(struct fuse_dev), GFP_KERNEL);
1023         if (fud) {
1024                 fud->fc = fuse_conn_get(fc);
1025                 fuse_pqueue_init(&fud->pq);
1026
1027                 spin_lock(&fc->lock);
1028                 list_add_tail(&fud->entry, &fc->devices);
1029                 spin_unlock(&fc->lock);
1030         }
1031
1032         return fud;
1033 }
1034 EXPORT_SYMBOL_GPL(fuse_dev_alloc);
1035
1036 void fuse_dev_free(struct fuse_dev *fud)
1037 {
1038         struct fuse_conn *fc = fud->fc;
1039
1040         if (fc) {
1041                 spin_lock(&fc->lock);
1042                 list_del(&fud->entry);
1043                 spin_unlock(&fc->lock);
1044
1045                 fuse_conn_put(fc);
1046         }
1047         kfree(fud);
1048 }
1049 EXPORT_SYMBOL_GPL(fuse_dev_free);
1050
1051 static int fuse_fill_super(struct super_block *sb, void *data, int silent)
1052 {
1053         struct fuse_dev *fud;
1054         struct fuse_conn *fc;
1055         struct inode *root;
1056         struct fuse_mount_data d;
1057         struct file *file;
1058         struct dentry *root_dentry;
1059         struct fuse_req *init_req;
1060         int err;
1061         int is_bdev = sb->s_bdev != NULL;
1062
1063         err = -EINVAL;
1064         if (sb->s_flags & MS_MANDLOCK)
1065                 goto err;
1066
1067         sb->s_flags &= ~(MS_NOSEC | MS_I_VERSION);
1068
1069         if (!parse_fuse_opt(data, &d, is_bdev))
1070                 goto err;
1071
1072         if (is_bdev) {
1073 #ifdef CONFIG_BLOCK
1074                 err = -EINVAL;
1075                 if (!sb_set_blocksize(sb, d.blksize))
1076                         goto err;
1077 #endif
1078         } else {
1079                 sb->s_blocksize = PAGE_SIZE;
1080                 sb->s_blocksize_bits = PAGE_SHIFT;
1081         }
1082         sb->s_magic = FUSE_SUPER_MAGIC;
1083         sb->s_op = &fuse_super_operations;
1084         sb->s_xattr = fuse_xattr_handlers;
1085         sb->s_maxbytes = MAX_LFS_FILESIZE;
1086         sb->s_time_gran = 1;
1087         sb->s_export_op = &fuse_export_operations;
1088
1089         file = fget(d.fd);
1090         err = -EINVAL;
1091         if (!file)
1092                 goto err;
1093
1094         if ((file->f_op != &fuse_dev_operations) ||
1095             (file->f_cred->user_ns != &init_user_ns))
1096                 goto err_fput;
1097
1098         fc = kmalloc(sizeof(*fc), GFP_KERNEL);
1099         err = -ENOMEM;
1100         if (!fc)
1101                 goto err_fput;
1102
1103         fuse_conn_init(fc);
1104         fc->release = fuse_free_conn;
1105
1106         fud = fuse_dev_alloc(fc);
1107         if (!fud)
1108                 goto err_put_conn;
1109
1110         fc->dev = sb->s_dev;
1111         fc->sb = sb;
1112         err = fuse_bdi_init(fc, sb);
1113         if (err)
1114                 goto err_dev_free;
1115
1116         sb->s_bdi = &fc->bdi;
1117
1118         /* Handle umasking inside the fuse code */
1119         if (sb->s_flags & MS_POSIXACL)
1120                 fc->dont_mask = 1;
1121         sb->s_flags |= MS_POSIXACL;
1122
1123         fc->default_permissions = d.default_permissions;
1124         fc->allow_other = d.allow_other;
1125         fc->user_id = d.user_id;
1126         fc->group_id = d.group_id;
1127         fc->max_read = max_t(unsigned, 4096, d.max_read);
1128
1129         /* Used by get_root_inode() */
1130         sb->s_fs_info = fc;
1131
1132         err = -ENOMEM;
1133         root = fuse_get_root_inode(sb, d.rootmode);
1134         sb->s_d_op = &fuse_root_dentry_operations;
1135         root_dentry = d_make_root(root);
1136         if (!root_dentry)
1137                 goto err_dev_free;
1138         /* Root dentry doesn't have .d_revalidate */
1139         sb->s_d_op = &fuse_dentry_operations;
1140
1141         init_req = fuse_request_alloc(0);
1142         if (!init_req)
1143                 goto err_put_root;
1144         __set_bit(FR_BACKGROUND, &init_req->flags);
1145
1146         if (is_bdev) {
1147                 fc->destroy_req = fuse_request_alloc(0);
1148                 if (!fc->destroy_req)
1149                         goto err_free_init_req;
1150         }
1151
1152         mutex_lock(&fuse_mutex);
1153         err = -EINVAL;
1154         if (file->private_data)
1155                 goto err_unlock;
1156
1157         err = fuse_ctl_add_conn(fc);
1158         if (err)
1159                 goto err_unlock;
1160
1161         list_add_tail(&fc->entry, &fuse_conn_list);
1162         sb->s_root = root_dentry;
1163         file->private_data = fud;
1164         mutex_unlock(&fuse_mutex);
1165         /*
1166          * atomic_dec_and_test() in fput() provides the necessary
1167          * memory barrier for file->private_data to be visible on all
1168          * CPUs after this
1169          */
1170         fput(file);
1171
1172         fuse_send_init(fc, init_req);
1173
1174         return 0;
1175
1176  err_unlock:
1177         mutex_unlock(&fuse_mutex);
1178  err_free_init_req:
1179         fuse_request_free(init_req);
1180  err_put_root:
1181         dput(root_dentry);
1182  err_dev_free:
1183         fuse_dev_free(fud);
1184  err_put_conn:
1185         fuse_bdi_destroy(fc);
1186         fuse_conn_put(fc);
1187  err_fput:
1188         fput(file);
1189  err:
1190         return err;
1191 }
1192
1193 static struct dentry *fuse_mount(struct file_system_type *fs_type,
1194                        int flags, const char *dev_name,
1195                        void *raw_data)
1196 {
1197         return mount_nodev(fs_type, flags, raw_data, fuse_fill_super);
1198 }
1199
1200 static void fuse_kill_sb_anon(struct super_block *sb)
1201 {
1202         struct fuse_conn *fc = get_fuse_conn_super(sb);
1203
1204         if (fc) {
1205                 down_write(&fc->killsb);
1206                 fc->sb = NULL;
1207                 up_write(&fc->killsb);
1208         }
1209
1210         kill_anon_super(sb);
1211 }
1212
1213 static struct file_system_type fuse_fs_type = {
1214         .owner          = THIS_MODULE,
1215         .name           = "fuse",
1216         .fs_flags       = FS_HAS_SUBTYPE,
1217         .mount          = fuse_mount,
1218         .kill_sb        = fuse_kill_sb_anon,
1219 };
1220 MODULE_ALIAS_FS("fuse");
1221
1222 #ifdef CONFIG_BLOCK
1223 static struct dentry *fuse_mount_blk(struct file_system_type *fs_type,
1224                            int flags, const char *dev_name,
1225                            void *raw_data)
1226 {
1227         return mount_bdev(fs_type, flags, dev_name, raw_data, fuse_fill_super);
1228 }
1229
1230 static void fuse_kill_sb_blk(struct super_block *sb)
1231 {
1232         struct fuse_conn *fc = get_fuse_conn_super(sb);
1233
1234         if (fc) {
1235                 down_write(&fc->killsb);
1236                 fc->sb = NULL;
1237                 up_write(&fc->killsb);
1238         }
1239
1240         kill_block_super(sb);
1241 }
1242
1243 static struct file_system_type fuseblk_fs_type = {
1244         .owner          = THIS_MODULE,
1245         .name           = "fuseblk",
1246         .mount          = fuse_mount_blk,
1247         .kill_sb        = fuse_kill_sb_blk,
1248         .fs_flags       = FS_REQUIRES_DEV | FS_HAS_SUBTYPE,
1249 };
1250 MODULE_ALIAS_FS("fuseblk");
1251
1252 static inline int register_fuseblk(void)
1253 {
1254         return register_filesystem(&fuseblk_fs_type);
1255 }
1256
1257 static inline void unregister_fuseblk(void)
1258 {
1259         unregister_filesystem(&fuseblk_fs_type);
1260 }
1261 #else
1262 static inline int register_fuseblk(void)
1263 {
1264         return 0;
1265 }
1266
1267 static inline void unregister_fuseblk(void)
1268 {
1269 }
1270 #endif
1271
1272 static void fuse_inode_init_once(void *foo)
1273 {
1274         struct inode *inode = foo;
1275
1276         inode_init_once(inode);
1277 }
1278
1279 static int __init fuse_fs_init(void)
1280 {
1281         int err;
1282
1283         fuse_inode_cachep = kmem_cache_create("fuse_inode",
1284                                               sizeof(struct fuse_inode), 0,
1285                                               SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT,
1286                                               fuse_inode_init_once);
1287         err = -ENOMEM;
1288         if (!fuse_inode_cachep)
1289                 goto out;
1290
1291         err = register_fuseblk();
1292         if (err)
1293                 goto out2;
1294
1295         err = register_filesystem(&fuse_fs_type);
1296         if (err)
1297                 goto out3;
1298
1299         return 0;
1300
1301  out3:
1302         unregister_fuseblk();
1303  out2:
1304         kmem_cache_destroy(fuse_inode_cachep);
1305  out:
1306         return err;
1307 }
1308
1309 static void fuse_fs_cleanup(void)
1310 {
1311         unregister_filesystem(&fuse_fs_type);
1312         unregister_fuseblk();
1313
1314         /*
1315          * Make sure all delayed rcu free inodes are flushed before we
1316          * destroy cache.
1317          */
1318         rcu_barrier();
1319         kmem_cache_destroy(fuse_inode_cachep);
1320 }
1321
1322 static struct kobject *fuse_kobj;
1323
1324 static int fuse_sysfs_init(void)
1325 {
1326         int err;
1327
1328         fuse_kobj = kobject_create_and_add("fuse", fs_kobj);
1329         if (!fuse_kobj) {
1330                 err = -ENOMEM;
1331                 goto out_err;
1332         }
1333
1334         err = sysfs_create_mount_point(fuse_kobj, "connections");
1335         if (err)
1336                 goto out_fuse_unregister;
1337
1338         return 0;
1339
1340  out_fuse_unregister:
1341         kobject_put(fuse_kobj);
1342  out_err:
1343         return err;
1344 }
1345
1346 static void fuse_sysfs_cleanup(void)
1347 {
1348         sysfs_remove_mount_point(fuse_kobj, "connections");
1349         kobject_put(fuse_kobj);
1350 }
1351
1352 static int __init fuse_init(void)
1353 {
1354         int res;
1355
1356         printk(KERN_INFO "fuse init (API version %i.%i)\n",
1357                FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);
1358
1359         INIT_LIST_HEAD(&fuse_conn_list);
1360         res = fuse_fs_init();
1361         if (res)
1362                 goto err;
1363
1364         res = fuse_dev_init();
1365         if (res)
1366                 goto err_fs_cleanup;
1367
1368         res = fuse_sysfs_init();
1369         if (res)
1370                 goto err_dev_cleanup;
1371
1372         res = fuse_ctl_init();
1373         if (res)
1374                 goto err_sysfs_cleanup;
1375
1376         sanitize_global_limit(&max_user_bgreq);
1377         sanitize_global_limit(&max_user_congthresh);
1378
1379         return 0;
1380
1381  err_sysfs_cleanup:
1382         fuse_sysfs_cleanup();
1383  err_dev_cleanup:
1384         fuse_dev_cleanup();
1385  err_fs_cleanup:
1386         fuse_fs_cleanup();
1387  err:
1388         return res;
1389 }
1390
1391 static void __exit fuse_exit(void)
1392 {
1393         printk(KERN_DEBUG "fuse exit\n");
1394
1395         fuse_ctl_cleanup();
1396         fuse_sysfs_cleanup();
1397         fuse_fs_cleanup();
1398         fuse_dev_cleanup();
1399 }
1400
1401 module_init(fuse_init);
1402 module_exit(fuse_exit);