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 #include <linux/pid_namespace.h>
  25
  26 MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
  27 MODULE_DESCRIPTION("Filesystem in Userspace");
  28 MODULE_LICENSE("GPL");
  29
  30 static struct kmem_cache *fuse_inode_cachep;
  31 struct list_head fuse_conn_list;
  32 DEFINE_MUTEX(fuse_mutex);
  33
  34 static int set_global_limit(const char *val, const struct kernel_param *kp);
  35
  36 unsigned max_user_bgreq;
  37 module_param_call(max_user_bgreq, set_global_limit, param_get_uint,
  38                   &max_user_bgreq, 0644);
  39 __MODULE_PARM_TYPE(max_user_bgreq, "uint");
  40 MODULE_PARM_DESC(max_user_bgreq,
  41  "Global limit for the maximum number of backgrounded requests an "
  42  "unprivileged user can set");
  43
  44 unsigned max_user_congthresh;
  45 module_param_call(max_user_congthresh, set_global_limit, param_get_uint,
  46                   &max_user_congthresh, 0644);
  47 __MODULE_PARM_TYPE(max_user_congthresh, "uint");
  48 MODULE_PARM_DESC(max_user_congthresh,
  49  "Global limit for the maximum congestion threshold an "
  50  "unprivileged user can set");
  51
  52 #define FUSE_SUPER_MAGIC 0x65735546
  53
  54 #define FUSE_DEFAULT_BLKSIZE 512
  55
  56 /** Maximum number of outstanding background requests */
  57 #define FUSE_DEFAULT_MAX_BACKGROUND 12
  58
  59 /** Congestion starts at 75% of maximum */
  60 #define FUSE_DEFAULT_CONGESTION_THRESHOLD (FUSE_DEFAULT_MAX_BACKGROUND * 3 / 4)
  61
  62 struct fuse_mount_data {
  63         int fd;
  64         unsigned rootmode;
  65         kuid_t user_id;
  66         kgid_t group_id;
  67         unsigned fd_present:1;
  68         unsigned rootmode_present:1;
  69         unsigned user_id_present:1;
  70         unsigned group_id_present:1;
  71         unsigned default_permissions:1;
  72         unsigned allow_other:1;
  73         unsigned max_read;
  74         unsigned blksize;
  75 };
  76
  77 struct fuse_forget_link *fuse_alloc_forget(void)
  78 {
  79         return kzalloc(sizeof(struct fuse_forget_link), GFP_KERNEL);
  80 }
  81
  82 static struct inode *fuse_alloc_inode(struct super_block *sb)
  83 {
  84         struct inode *inode;
  85         struct fuse_inode *fi;
  86
  87         inode = kmem_cache_alloc(fuse_inode_cachep, GFP_KERNEL);
  88         if (!inode)
  89                 return NULL;
  90
  91         fi = get_fuse_inode(inode);
  92         fi->i_time = 0;
  93         fi->nodeid = 0;
  94         fi->nlookup = 0;
  95         fi->attr_version = 0;
  96         fi->writectr = 0;
  97         fi->orig_ino = 0;
  98         fi->state = 0;
  99         INIT_LIST_HEAD(&fi->write_files);
 100         INIT_LIST_HEAD(&fi->queued_writes);
 101         INIT_LIST_HEAD(&fi->writepages);
 102         init_waitqueue_head(&fi->page_waitq);
 103         mutex_init(&fi->mutex);
 104         fi->forget = fuse_alloc_forget();
 105         if (!fi->forget) {
 106                 kmem_cache_free(fuse_inode_cachep, inode);
 107                 return NULL;
 108         }
 109
 110         return inode;
 111 }
 112
 113 static void fuse_i_callback(struct rcu_head *head)
 114 {
 115         struct inode *inode = container_of(head, struct inode, i_rcu);
 116         kmem_cache_free(fuse_inode_cachep, inode);
 117 }
 118
 119 static void fuse_destroy_inode(struct inode *inode)
 120 {
 121         struct fuse_inode *fi = get_fuse_inode(inode);
 122         BUG_ON(!list_empty(&fi->write_files));
 123         BUG_ON(!list_empty(&fi->queued_writes));
 124         mutex_destroy(&fi->mutex);
 125         kfree(fi->forget);
 126         call_rcu(&inode->i_rcu, fuse_i_callback);
 127 }
 128
 129 static void fuse_evict_inode(struct inode *inode)
 130 {
 131         truncate_inode_pages_final(&inode->i_data);
 132         clear_inode(inode);
 133         if (inode->i_sb->s_flags & SB_ACTIVE) {
 134                 struct fuse_conn *fc = get_fuse_conn(inode);
 135                 struct fuse_inode *fi = get_fuse_inode(inode);
 136                 fuse_queue_forget(fc, fi->forget, fi->nodeid, fi->nlookup);
 137                 fi->forget = NULL;
 138         }
 139 }
 140
 141 static int fuse_remount_fs(struct super_block *sb, int *flags, char *data)
 142 {
 143         sync_filesystem(sb);
 144         if (*flags & SB_MANDLOCK)
 145                 return -EINVAL;
 146
 147         return 0;
 148 }
 149
 150 /*
 151  * ino_t is 32-bits on 32-bit arch. We have to squash the 64-bit value down
 152  * so that it will fit.
 153  */
 154 static ino_t fuse_squash_ino(u64 ino64)
 155 {
 156         ino_t ino = (ino_t) ino64;
 157         if (sizeof(ino_t) < sizeof(u64))
 158                 ino ^= ino64 >> (sizeof(u64) - sizeof(ino_t)) * 8;
 159         return ino;
 160 }
 161
 162 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
 163                                    u64 attr_valid)
 164 {
 165         struct fuse_conn *fc = get_fuse_conn(inode);
 166         struct fuse_inode *fi = get_fuse_inode(inode);
 167
 168         fi->attr_version = ++fc->attr_version;
 169         fi->i_time = attr_valid;
 170
 171         inode->i_ino     = fuse_squash_ino(attr->ino);
 172         inode->i_mode    = (inode->i_mode & S_IFMT) | (attr->mode & 07777);
 173         set_nlink(inode, attr->nlink);
 174         inode->i_uid     = make_kuid(fc->user_ns, attr->uid);
 175         inode->i_gid     = make_kgid(fc->user_ns, attr->gid);
 176         inode->i_blocks  = attr->blocks;
 177
 178         /* Sanitize nsecs */
 179         attr->atimensec = min_t(u32, attr->atimensec, NSEC_PER_SEC - 1);
 180         attr->mtimensec = min_t(u32, attr->mtimensec, NSEC_PER_SEC - 1);
 181         attr->ctimensec = min_t(u32, attr->ctimensec, NSEC_PER_SEC - 1);
 182
 183         inode->i_atime.tv_sec   = attr->atime;
 184         inode->i_atime.tv_nsec  = attr->atimensec;
 185         /* mtime from server may be stale due to local buffered write */
 186         if (!fc->writeback_cache || !S_ISREG(inode->i_mode)) {
 187                 inode->i_mtime.tv_sec   = attr->mtime;
 188                 inode->i_mtime.tv_nsec  = attr->mtimensec;
 189                 inode->i_ctime.tv_sec   = attr->ctime;
 190                 inode->i_ctime.tv_nsec  = attr->ctimensec;
 191         }
 192
 193         if (attr->blksize != 0)
 194                 inode->i_blkbits = ilog2(attr->blksize);
 195         else
 196                 inode->i_blkbits = inode->i_sb->s_blocksize_bits;
 197
 198         /*
 199          * Don't set the sticky bit in i_mode, unless we want the VFS
 200          * to check permissions.  This prevents failures due to the
 201          * check in may_delete().
 202          */
 203         fi->orig_i_mode = inode->i_mode;
 204         if (!fc->default_permissions)
 205                 inode->i_mode &= ~S_ISVTX;
 206
 207         fi->orig_ino = attr->ino;
 208 }
 209
 210 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
 211                             u64 attr_valid, u64 attr_version)
 212 {
 213         struct fuse_conn *fc = get_fuse_conn(inode);
 214         struct fuse_inode *fi = get_fuse_inode(inode);
 215         bool is_wb = fc->writeback_cache;
 216         loff_t oldsize;
 217         struct timespec64 old_mtime;
 218
 219         spin_lock(&fc->lock);
 220         if ((attr_version != 0 && fi->attr_version > attr_version) ||
 221             test_bit(FUSE_I_SIZE_UNSTABLE, &fi->state)) {
 222                 spin_unlock(&fc->lock);
 223                 return;
 224         }
 225
 226         old_mtime = inode->i_mtime;
 227         fuse_change_attributes_common(inode, attr, attr_valid);
 228
 229         oldsize = inode->i_size;
 230         /*
 231          * In case of writeback_cache enabled, the cached writes beyond EOF
 232          * extend local i_size without keeping userspace server in sync. So,
 233          * attr->size coming from server can be stale. We cannot trust it.
 234          */
 235         if (!is_wb || !S_ISREG(inode->i_mode))
 236                 i_size_write(inode, attr->size);
 237         spin_unlock(&fc->lock);
 238
 239         if (!is_wb && S_ISREG(inode->i_mode)) {
 240                 bool inval = false;
 241
 242                 if (oldsize != attr->size) {
 243                         truncate_pagecache(inode, attr->size);
 244                         inval = true;
 245                 } else if (fc->auto_inval_data) {
 246                         struct timespec64 new_mtime = {
 247                                 .tv_sec = attr->mtime,
 248                                 .tv_nsec = attr->mtimensec,
 249                         };
 250
 251                         /*
 252                          * Auto inval mode also checks and invalidates if mtime
 253                          * has changed.
 254                          */
 255                         if (!timespec64_equal(&old_mtime, &new_mtime))
 256                                 inval = true;
 257                 }
 258
 259                 if (inval)
 260                         invalidate_inode_pages2(inode->i_mapping);
 261         }
 262 }
 263
 264 static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr)
 265 {
 266         inode->i_mode = attr->mode & S_IFMT;
 267         inode->i_size = attr->size;
 268         inode->i_mtime.tv_sec  = attr->mtime;
 269         inode->i_mtime.tv_nsec = attr->mtimensec;
 270         inode->i_ctime.tv_sec  = attr->ctime;
 271         inode->i_ctime.tv_nsec = attr->ctimensec;
 272         if (S_ISREG(inode->i_mode)) {
 273                 fuse_init_common(inode);
 274                 fuse_init_file_inode(inode);
 275         } else if (S_ISDIR(inode->i_mode))
 276                 fuse_init_dir(inode);
 277         else if (S_ISLNK(inode->i_mode))
 278                 fuse_init_symlink(inode);
 279         else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
 280                  S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
 281                 fuse_init_common(inode);
 282                 init_special_inode(inode, inode->i_mode,
 283                                    new_decode_dev(attr->rdev));
 284         } else
 285                 BUG();
 286 }
 287
 288 int fuse_inode_eq(struct inode *inode, void *_nodeidp)
 289 {
 290         u64 nodeid = *(u64 *) _nodeidp;
 291         if (get_node_id(inode) == nodeid)
 292                 return 1;
 293         else
 294                 return 0;
 295 }
 296
 297 static int fuse_inode_set(struct inode *inode, void *_nodeidp)
 298 {
 299         u64 nodeid = *(u64 *) _nodeidp;
 300         get_fuse_inode(inode)->nodeid = nodeid;
 301         return 0;
 302 }
 303
 304 struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
 305                         int generation, struct fuse_attr *attr,
 306                         u64 attr_valid, u64 attr_version)
 307 {
 308         struct inode *inode;
 309         struct fuse_inode *fi;
 310         struct fuse_conn *fc = get_fuse_conn_super(sb);
 311
 312  retry:
 313         inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid);
 314         if (!inode)
 315                 return NULL;
 316
 317         if ((inode->i_state & I_NEW)) {
 318                 inode->i_flags |= S_NOATIME;
 319                 if (!fc->writeback_cache || !S_ISREG(attr->mode))
 320                         inode->i_flags |= S_NOCMTIME;
 321                 inode->i_generation = generation;
 322                 fuse_init_inode(inode, attr);
 323                 unlock_new_inode(inode);
 324         } else if ((inode->i_mode ^ attr->mode) & S_IFMT) {
 325                 /* Inode has changed type, any I/O on the old should fail */
 326                 fuse_make_bad(inode);
 327                 iput(inode);
 328                 goto retry;
 329         }
 330
 331         fi = get_fuse_inode(inode);
 332         spin_lock(&fc->lock);
 333         fi->nlookup++;
 334         spin_unlock(&fc->lock);
 335         fuse_change_attributes(inode, attr, attr_valid, attr_version);
 336
 337         return inode;
 338 }
 339
 340 int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid,
 341                              loff_t offset, loff_t len)
 342 {
 343         struct inode *inode;
 344         pgoff_t pg_start;
 345         pgoff_t pg_end;
 346
 347         inode = ilookup5(sb, nodeid, fuse_inode_eq, &nodeid);
 348         if (!inode)
 349                 return -ENOENT;
 350
 351         fuse_invalidate_attr(inode);
 352         forget_all_cached_acls(inode);
 353         if (offset >= 0) {
 354                 pg_start = offset >> PAGE_SHIFT;
 355                 if (len <= 0)
 356                         pg_end = -1;
 357                 else
 358                         pg_end = (offset + len - 1) >> PAGE_SHIFT;
 359                 invalidate_inode_pages2_range(inode->i_mapping,
 360                                               pg_start, pg_end);
 361         }
 362         iput(inode);
 363         return 0;
 364 }
 365
 366 bool fuse_lock_inode(struct inode *inode)
 367 {
 368         bool locked = false;
 369
 370         if (!get_fuse_conn(inode)->parallel_dirops) {
 371                 mutex_lock(&get_fuse_inode(inode)->mutex);
 372                 locked = true;
 373         }
 374
 375         return locked;
 376 }
 377
 378 void fuse_unlock_inode(struct inode *inode, bool locked)
 379 {
 380         if (locked)
 381                 mutex_unlock(&get_fuse_inode(inode)->mutex);
 382 }
 383
 384 static void fuse_umount_begin(struct super_block *sb)
 385 {
 386         fuse_abort_conn(get_fuse_conn_super(sb), false);
 387 }
 388
 389 static void fuse_send_destroy(struct fuse_conn *fc)
 390 {
 391         struct fuse_req *req = fc->destroy_req;
 392         if (req && fc->conn_init) {
 393                 fc->destroy_req = NULL;
 394                 req->in.h.opcode = FUSE_DESTROY;
 395                 __set_bit(FR_FORCE, &req->flags);
 396                 __clear_bit(FR_BACKGROUND, &req->flags);
 397                 fuse_request_send(fc, req);
 398                 fuse_put_request(fc, req);
 399         }
 400 }
 401
 402 static void fuse_put_super(struct super_block *sb)
 403 {
 404         struct fuse_conn *fc = get_fuse_conn_super(sb);
 405
 406         mutex_lock(&fuse_mutex);
 407         list_del(&fc->entry);
 408         fuse_ctl_remove_conn(fc);
 409         mutex_unlock(&fuse_mutex);
 410
 411         fuse_conn_put(fc);
 412 }
 413
 414 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr)
 415 {
 416         stbuf->f_type    = FUSE_SUPER_MAGIC;
 417         stbuf->f_bsize   = attr->bsize;
 418         stbuf->f_frsize  = attr->frsize;
 419         stbuf->f_blocks  = attr->blocks;
 420         stbuf->f_bfree   = attr->bfree;
 421         stbuf->f_bavail  = attr->bavail;
 422         stbuf->f_files   = attr->files;
 423         stbuf->f_ffree   = attr->ffree;
 424         stbuf->f_namelen = attr->namelen;
 425         /* fsid is left zero */
 426 }
 427
 428 static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf)
 429 {
 430         struct super_block *sb = dentry->d_sb;
 431         struct fuse_conn *fc = get_fuse_conn_super(sb);
 432         FUSE_ARGS(args);
 433         struct fuse_statfs_out outarg;
 434         int err;
 435
 436         if (!fuse_allow_current_process(fc)) {
 437                 buf->f_type = FUSE_SUPER_MAGIC;
 438                 return 0;
 439         }
 440
 441         memset(&outarg, 0, sizeof(outarg));
 442         args.in.numargs = 0;
 443         args.in.h.opcode = FUSE_STATFS;
 444         args.in.h.nodeid = get_node_id(d_inode(dentry));
 445         args.out.numargs = 1;
 446         args.out.args[0].size = sizeof(outarg);
 447         args.out.args[0].value = &outarg;
 448         err = fuse_simple_request(fc, &args);
 449         if (!err)
 450                 convert_fuse_statfs(buf, &outarg.st);
 451         return err;
 452 }
 453
 454 enum {
 455         OPT_FD,
 456         OPT_ROOTMODE,
 457         OPT_USER_ID,
 458         OPT_GROUP_ID,
 459         OPT_DEFAULT_PERMISSIONS,
 460         OPT_ALLOW_OTHER,
 461         OPT_MAX_READ,
 462         OPT_BLKSIZE,
 463         OPT_ERR
 464 };
 465
 466 static const match_table_t tokens = {
 467         {OPT_FD,                        "fd=%u"},
 468         {OPT_ROOTMODE,                  "rootmode=%o"},
 469         {OPT_USER_ID,                   "user_id=%u"},
 470         {OPT_GROUP_ID,                  "group_id=%u"},
 471         {OPT_DEFAULT_PERMISSIONS,       "default_permissions"},
 472         {OPT_ALLOW_OTHER,               "allow_other"},
 473         {OPT_MAX_READ,                  "max_read=%u"},
 474         {OPT_BLKSIZE,                   "blksize=%u"},
 475         {OPT_ERR,                       NULL}
 476 };
 477
 478 static int fuse_match_uint(substring_t *s, unsigned int *res)
 479 {
 480         int err = -ENOMEM;
 481         char *buf = match_strdup(s);
 482         if (buf) {
 483                 err = kstrtouint(buf, 10, res);
 484                 kfree(buf);
 485         }
 486         return err;
 487 }
 488
 489 static int parse_fuse_opt(char *opt, struct fuse_mount_data *d, int is_bdev,
 490                           struct user_namespace *user_ns)
 491 {
 492         char *p;
 493         memset(d, 0, sizeof(struct fuse_mount_data));
 494         d->max_read = ~0;
 495         d->blksize = FUSE_DEFAULT_BLKSIZE;
 496
 497         while ((p = strsep(&opt, ",")) != NULL) {
 498                 int token;
 499                 int value;
 500                 unsigned uv;
 501                 substring_t args[MAX_OPT_ARGS];
 502                 if (!*p)
 503                         continue;
 504
 505                 token = match_token(p, tokens, args);
 506                 switch (token) {
 507                 case OPT_FD:
 508                         if (match_int(&args[0], &value))
 509                                 return 0;
 510                         d->fd = value;
 511                         d->fd_present = 1;
 512                         break;
 513
 514                 case OPT_ROOTMODE:
 515                         if (match_octal(&args[0], &value))
 516                                 return 0;
 517                         if (!fuse_valid_type(value))
 518                                 return 0;
 519                         d->rootmode = value;
 520                         d->rootmode_present = 1;
 521                         break;
 522
 523                 case OPT_USER_ID:
 524                         if (fuse_match_uint(&args[0], &uv))
 525                                 return 0;
 526                         d->user_id = make_kuid(user_ns, uv);
 527                         if (!uid_valid(d->user_id))
 528                                 return 0;
 529                         d->user_id_present = 1;
 530                         break;
 531
 532                 case OPT_GROUP_ID:
 533                         if (fuse_match_uint(&args[0], &uv))
 534                                 return 0;
 535                         d->group_id = make_kgid(user_ns, uv);
 536                         if (!gid_valid(d->group_id))
 537                                 return 0;
 538                         d->group_id_present = 1;
 539                         break;
 540
 541                 case OPT_DEFAULT_PERMISSIONS:
 542                         d->default_permissions = 1;
 543                         break;
 544
 545                 case OPT_ALLOW_OTHER:
 546                         d->allow_other = 1;
 547                         break;
 548
 549                 case OPT_MAX_READ:
 550                         if (match_int(&args[0], &value))
 551                                 return 0;
 552                         d->max_read = value;
 553                         break;
 554
 555                 case OPT_BLKSIZE:
 556                         if (!is_bdev || match_int(&args[0], &value))
 557                                 return 0;
 558                         d->blksize = value;
 559                         break;
 560
 561                 default:
 562                         return 0;
 563                 }
 564         }
 565
 566         if (!d->fd_present || !d->rootmode_present ||
 567             !d->user_id_present || !d->group_id_present)
 568                 return 0;
 569
 570         return 1;
 571 }
 572
 573 static int fuse_show_options(struct seq_file *m, struct dentry *root)
 574 {
 575         struct super_block *sb = root->d_sb;
 576         struct fuse_conn *fc = get_fuse_conn_super(sb);
 577
 578         seq_printf(m, ",user_id=%u", from_kuid_munged(fc->user_ns, fc->user_id));
 579         seq_printf(m, ",group_id=%u", from_kgid_munged(fc->user_ns, fc->group_id));
 580         if (fc->default_permissions)
 581                 seq_puts(m, ",default_permissions");
 582         if (fc->allow_other)
 583                 seq_puts(m, ",allow_other");
 584         if (fc->max_read != ~0)
 585                 seq_printf(m, ",max_read=%u", fc->max_read);
 586         if (sb->s_bdev && sb->s_blocksize != FUSE_DEFAULT_BLKSIZE)
 587                 seq_printf(m, ",blksize=%lu", sb->s_blocksize);
 588         return 0;
 589 }
 590
 591 static void fuse_iqueue_init(struct fuse_iqueue *fiq)
 592 {
 593         memset(fiq, 0, sizeof(struct fuse_iqueue));
 594         spin_lock_init(&fiq->lock);
 595         init_waitqueue_head(&fiq->waitq);
 596         INIT_LIST_HEAD(&fiq->pending);
 597         INIT_LIST_HEAD(&fiq->interrupts);
 598         fiq->forget_list_tail = &fiq->forget_list_head;
 599         fiq->connected = 1;
 600 }
 601
 602 static void fuse_pqueue_init(struct fuse_pqueue *fpq)
 603 {
 604         memset(fpq, 0, sizeof(struct fuse_pqueue));
 605         spin_lock_init(&fpq->lock);
 606         INIT_LIST_HEAD(&fpq->processing);
 607         INIT_LIST_HEAD(&fpq->io);
 608         fpq->connected = 1;
 609 }
 610
 611 void fuse_conn_init(struct fuse_conn *fc, struct user_namespace *user_ns)
 612 {
 613         memset(fc, 0, sizeof(*fc));
 614         spin_lock_init(&fc->lock);
 615         init_rwsem(&fc->killsb);
 616         refcount_set(&fc->count, 1);
 617         atomic_set(&fc->dev_count, 1);
 618         init_waitqueue_head(&fc->blocked_waitq);
 619         init_waitqueue_head(&fc->reserved_req_waitq);
 620         fuse_iqueue_init(&fc->iq);
 621         INIT_LIST_HEAD(&fc->bg_queue);
 622         INIT_LIST_HEAD(&fc->entry);
 623         INIT_LIST_HEAD(&fc->devices);
 624         atomic_set(&fc->num_waiting, 0);
 625         fc->max_background = FUSE_DEFAULT_MAX_BACKGROUND;
 626         fc->congestion_threshold = FUSE_DEFAULT_CONGESTION_THRESHOLD;
 627         fc->khctr = 0;
 628         fc->polled_files = RB_ROOT;
 629         fc->blocked = 0;
 630         fc->initialized = 0;
 631         fc->connected = 1;
 632         fc->attr_version = 1;
 633         get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key));
 634         fc->pid_ns = get_pid_ns(task_active_pid_ns(current));
 635         fc->user_ns = get_user_ns(user_ns);
 636 }
 637 EXPORT_SYMBOL_GPL(fuse_conn_init);
 638
 639 void fuse_conn_put(struct fuse_conn *fc)
 640 {
 641         if (refcount_dec_and_test(&fc->count)) {
 642                 if (fc->destroy_req)
 643                         fuse_request_free(fc->destroy_req);
 644                 put_pid_ns(fc->pid_ns);
 645                 put_user_ns(fc->user_ns);
 646                 fc->release(fc);
 647         }
 648 }
 649 EXPORT_SYMBOL_GPL(fuse_conn_put);
 650
 651 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc)
 652 {
 653         refcount_inc(&fc->count);
 654         return fc;
 655 }
 656 EXPORT_SYMBOL_GPL(fuse_conn_get);
 657
 658 static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned mode)
 659 {
 660         struct fuse_attr attr;
 661         memset(&attr, 0, sizeof(attr));
 662
 663         attr.mode = mode;
 664         attr.ino = FUSE_ROOT_ID;
 665         attr.nlink = 1;
 666         return fuse_iget(sb, 1, 0, &attr, 0, 0);
 667 }
 668
 669 struct fuse_inode_handle {
 670         u64 nodeid;
 671         u32 generation;
 672 };
 673
 674 static struct dentry *fuse_get_dentry(struct super_block *sb,
 675                                       struct fuse_inode_handle *handle)
 676 {
 677         struct fuse_conn *fc = get_fuse_conn_super(sb);
 678         struct inode *inode;
 679         struct dentry *entry;
 680         int err = -ESTALE;
 681
 682         if (handle->nodeid == 0)
 683                 goto out_err;
 684
 685         inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid);
 686         if (!inode) {
 687                 struct fuse_entry_out outarg;
 688                 const struct qstr name = QSTR_INIT(".", 1);
 689
 690                 if (!fc->export_support)
 691                         goto out_err;
 692
 693                 err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg,
 694                                        &inode);
 695                 if (err && err != -ENOENT)
 696                         goto out_err;
 697                 if (err || !inode) {
 698                         err = -ESTALE;
 699                         goto out_err;
 700                 }
 701                 err = -EIO;
 702                 if (get_node_id(inode) != handle->nodeid)
 703                         goto out_iput;
 704         }
 705         err = -ESTALE;
 706         if (inode->i_generation != handle->generation)
 707                 goto out_iput;
 708
 709         entry = d_obtain_alias(inode);
 710         if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID)
 711                 fuse_invalidate_entry_cache(entry);
 712
 713         return entry;
 714
 715  out_iput:
 716         iput(inode);
 717  out_err:
 718         return ERR_PTR(err);
 719 }
 720
 721 static int fuse_encode_fh(struct inode *inode, u32 *fh, int *max_len,
 722                            struct inode *parent)
 723 {
 724         int len = parent ? 6 : 3;
 725         u64 nodeid;
 726         u32 generation;
 727
 728         if (*max_len < len) {
 729                 *max_len = len;
 730                 return  FILEID_INVALID;
 731         }
 732
 733         nodeid = get_fuse_inode(inode)->nodeid;
 734         generation = inode->i_generation;
 735
 736         fh[0] = (u32)(nodeid >> 32);
 737         fh[1] = (u32)(nodeid & 0xffffffff);
 738         fh[2] = generation;
 739
 740         if (parent) {
 741                 nodeid = get_fuse_inode(parent)->nodeid;
 742                 generation = parent->i_generation;
 743
 744                 fh[3] = (u32)(nodeid >> 32);
 745                 fh[4] = (u32)(nodeid & 0xffffffff);
 746                 fh[5] = generation;
 747         }
 748
 749         *max_len = len;
 750         return parent ? 0x82 : 0x81;
 751 }
 752
 753 static struct dentry *fuse_fh_to_dentry(struct super_block *sb,
 754                 struct fid *fid, int fh_len, int fh_type)
 755 {
 756         struct fuse_inode_handle handle;
 757
 758         if ((fh_type != 0x81 && fh_type != 0x82) || fh_len < 3)
 759                 return NULL;
 760
 761         handle.nodeid = (u64) fid->raw[0] << 32;
 762         handle.nodeid |= (u64) fid->raw[1];
 763         handle.generation = fid->raw[2];
 764         return fuse_get_dentry(sb, &handle);
 765 }
 766
 767 static struct dentry *fuse_fh_to_parent(struct super_block *sb,
 768                 struct fid *fid, int fh_len, int fh_type)
 769 {
 770         struct fuse_inode_handle parent;
 771
 772         if (fh_type != 0x82 || fh_len < 6)
 773                 return NULL;
 774
 775         parent.nodeid = (u64) fid->raw[3] << 32;
 776         parent.nodeid |= (u64) fid->raw[4];
 777         parent.generation = fid->raw[5];
 778         return fuse_get_dentry(sb, &parent);
 779 }
 780
 781 static struct dentry *fuse_get_parent(struct dentry *child)
 782 {
 783         struct inode *child_inode = d_inode(child);
 784         struct fuse_conn *fc = get_fuse_conn(child_inode);
 785         struct inode *inode;
 786         struct dentry *parent;
 787         struct fuse_entry_out outarg;
 788         const struct qstr name = QSTR_INIT("..", 2);
 789         int err;
 790
 791         if (!fc->export_support)
 792                 return ERR_PTR(-ESTALE);
 793
 794         err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode),
 795                                &name, &outarg, &inode);
 796         if (err) {
 797                 if (err == -ENOENT)
 798                         return ERR_PTR(-ESTALE);
 799                 return ERR_PTR(err);
 800         }
 801
 802         parent = d_obtain_alias(inode);
 803         if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID)
 804                 fuse_invalidate_entry_cache(parent);
 805
 806         return parent;
 807 }
 808
 809 static const struct export_operations fuse_export_operations = {
 810         .fh_to_dentry   = fuse_fh_to_dentry,
 811         .fh_to_parent   = fuse_fh_to_parent,
 812         .encode_fh      = fuse_encode_fh,
 813         .get_parent     = fuse_get_parent,
 814 };
 815
 816 static const struct super_operations fuse_super_operations = {
 817         .alloc_inode    = fuse_alloc_inode,
 818         .destroy_inode  = fuse_destroy_inode,
 819         .evict_inode    = fuse_evict_inode,
 820         .write_inode    = fuse_write_inode,
 821         .drop_inode     = generic_delete_inode,
 822         .remount_fs     = fuse_remount_fs,
 823         .put_super      = fuse_put_super,
 824         .umount_begin   = fuse_umount_begin,
 825         .statfs         = fuse_statfs,
 826         .show_options   = fuse_show_options,
 827 };
 828
 829 static void sanitize_global_limit(unsigned *limit)
 830 {
 831         if (*limit == 0)
 832                 *limit = ((totalram_pages << PAGE_SHIFT) >> 13) /
 833                          sizeof(struct fuse_req);
 834
 835         if (*limit >= 1 << 16)
 836                 *limit = (1 << 16) - 1;
 837 }
 838
 839 static int set_global_limit(const char *val, const struct kernel_param *kp)
 840 {
 841         int rv;
 842
 843         rv = param_set_uint(val, kp);
 844         if (rv)
 845                 return rv;
 846
 847         sanitize_global_limit((unsigned *)kp->arg);
 848
 849         return 0;
 850 }
 851
 852 static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg)
 853 {
 854         int cap_sys_admin = capable(CAP_SYS_ADMIN);
 855
 856         if (arg->minor < 13)
 857                 return;
 858
 859         sanitize_global_limit(&max_user_bgreq);
 860         sanitize_global_limit(&max_user_congthresh);
 861
 862         if (arg->max_background) {
 863                 fc->max_background = arg->max_background;
 864
 865                 if (!cap_sys_admin && fc->max_background > max_user_bgreq)
 866                         fc->max_background = max_user_bgreq;
 867         }
 868         if (arg->congestion_threshold) {
 869                 fc->congestion_threshold = arg->congestion_threshold;
 870
 871                 if (!cap_sys_admin &&
 872                     fc->congestion_threshold > max_user_congthresh)
 873                         fc->congestion_threshold = max_user_congthresh;
 874         }
 875 }
 876
 877 static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
 878 {
 879         struct fuse_init_out *arg = &req->misc.init_out;
 880
 881         if (req->out.h.error || arg->major != FUSE_KERNEL_VERSION)
 882                 fc->conn_error = 1;
 883         else {
 884                 unsigned long ra_pages;
 885
 886                 process_init_limits(fc, arg);
 887
 888                 if (arg->minor >= 6) {
 889                         ra_pages = arg->max_readahead / PAGE_SIZE;
 890                         if (arg->flags & FUSE_ASYNC_READ)
 891                                 fc->async_read = 1;
 892                         if (!(arg->flags & FUSE_POSIX_LOCKS))
 893                                 fc->no_lock = 1;
 894                         if (arg->minor >= 17) {
 895                                 if (!(arg->flags & FUSE_FLOCK_LOCKS))
 896                                         fc->no_flock = 1;
 897                         } else {
 898                                 if (!(arg->flags & FUSE_POSIX_LOCKS))
 899                                         fc->no_flock = 1;
 900                         }
 901                         if (arg->flags & FUSE_ATOMIC_O_TRUNC)
 902                                 fc->atomic_o_trunc = 1;
 903                         if (arg->minor >= 9) {
 904                                 /* LOOKUP has dependency on proto version */
 905                                 if (arg->flags & FUSE_EXPORT_SUPPORT)
 906                                         fc->export_support = 1;
 907                         }
 908                         if (arg->flags & FUSE_BIG_WRITES)
 909                                 fc->big_writes = 1;
 910                         if (arg->flags & FUSE_DONT_MASK)
 911                                 fc->dont_mask = 1;
 912                         if (arg->flags & FUSE_AUTO_INVAL_DATA)
 913                                 fc->auto_inval_data = 1;
 914                         if (arg->flags & FUSE_DO_READDIRPLUS) {
 915                                 fc->do_readdirplus = 1;
 916                                 if (arg->flags & FUSE_READDIRPLUS_AUTO)
 917                                         fc->readdirplus_auto = 1;
 918                         }
 919                         if (arg->flags & FUSE_ASYNC_DIO)
 920                                 fc->async_dio = 1;
 921                         if (arg->flags & FUSE_WRITEBACK_CACHE)
 922                                 fc->writeback_cache = 1;
 923                         if (arg->flags & FUSE_PARALLEL_DIROPS)
 924                                 fc->parallel_dirops = 1;
 925                         if (arg->flags & FUSE_HANDLE_KILLPRIV)
 926                                 fc->handle_killpriv = 1;
 927                         if (arg->time_gran && arg->time_gran <= 1000000000)
 928                                 fc->sb->s_time_gran = arg->time_gran;
 929                         if ((arg->flags & FUSE_POSIX_ACL)) {
 930                                 fc->default_permissions = 1;
 931                                 fc->posix_acl = 1;
 932                                 fc->sb->s_xattr = fuse_acl_xattr_handlers;
 933                         }
 934                         if (arg->flags & FUSE_ABORT_ERROR)
 935                                 fc->abort_err = 1;
 936                 } else {
 937                         ra_pages = fc->max_read / PAGE_SIZE;
 938                         fc->no_lock = 1;
 939                         fc->no_flock = 1;
 940                 }
 941
 942                 fc->sb->s_bdi->ra_pages =
 943                                 min(fc->sb->s_bdi->ra_pages, ra_pages);
 944                 fc->minor = arg->minor;
 945                 fc->max_write = arg->minor < 5 ? 4096 : arg->max_write;
 946                 fc->max_write = max_t(unsigned, 4096, fc->max_write);
 947                 fc->conn_init = 1;
 948         }
 949         fuse_set_initialized(fc);
 950         wake_up_all(&fc->blocked_waitq);
 951 }
 952
 953 static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req)
 954 {
 955         struct fuse_init_in *arg = &req->misc.init_in;
 956
 957         arg->major = FUSE_KERNEL_VERSION;
 958         arg->minor = FUSE_KERNEL_MINOR_VERSION;
 959         arg->max_readahead = fc->sb->s_bdi->ra_pages * PAGE_SIZE;
 960         arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC |
 961                 FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK |
 962                 FUSE_SPLICE_WRITE | FUSE_SPLICE_MOVE | FUSE_SPLICE_READ |
 963                 FUSE_FLOCK_LOCKS | FUSE_HAS_IOCTL_DIR | FUSE_AUTO_INVAL_DATA |
 964                 FUSE_DO_READDIRPLUS | FUSE_READDIRPLUS_AUTO | FUSE_ASYNC_DIO |
 965                 FUSE_WRITEBACK_CACHE | FUSE_NO_OPEN_SUPPORT |
 966                 FUSE_PARALLEL_DIROPS | FUSE_HANDLE_KILLPRIV | FUSE_POSIX_ACL |
 967                 FUSE_ABORT_ERROR;
 968         req->in.h.opcode = FUSE_INIT;
 969         req->in.numargs = 1;
 970         req->in.args[0].size = sizeof(*arg);
 971         req->in.args[0].value = arg;
 972         req->out.numargs = 1;
 973         /* Variable length argument used for backward compatibility
 974            with interface version < 7.5.  Rest of init_out is zeroed
 975            by do_get_request(), so a short reply is not a problem */
 976         req->out.argvar = 1;
 977         req->out.args[0].size = sizeof(struct fuse_init_out);
 978         req->out.args[0].value = &req->misc.init_out;
 979         req->end = process_init_reply;
 980         fuse_request_send_background(fc, req);
 981 }
 982
 983 static void fuse_free_conn(struct fuse_conn *fc)
 984 {
 985         WARN_ON(!list_empty(&fc->devices));
 986         kfree_rcu(fc, rcu);
 987 }
 988
 989 static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
 990 {
 991         int err;
 992         char *suffix = "";
 993
 994         if (sb->s_bdev) {
 995                 suffix = "-fuseblk";
 996                 /*
 997                  * sb->s_bdi points to blkdev's bdi however we want to redirect
 998                  * it to our private bdi...
 999                  */
1000                 bdi_put(sb->s_bdi);
1001                 sb->s_bdi = &noop_backing_dev_info;
1002         }
1003         err = super_setup_bdi_name(sb, "%u:%u%s", MAJOR(fc->dev),
1004                                    MINOR(fc->dev), suffix);
1005         if (err)
1006                 return err;
1007
1008         sb->s_bdi->ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_SIZE;
1009         /* fuse does it's own writeback accounting */
1010         sb->s_bdi->capabilities = BDI_CAP_NO_ACCT_WB | BDI_CAP_STRICTLIMIT;
1011
1012         /*
1013          * For a single fuse filesystem use max 1% of dirty +
1014          * writeback threshold.
1015          *
1016          * This gives about 1M of write buffer for memory maps on a
1017          * machine with 1G and 10% dirty_ratio, which should be more
1018          * than enough.
1019          *
1020          * Privileged users can raise it by writing to
1021          *
1022          *    /sys/class/bdi/<bdi>/max_ratio
1023          */
1024         bdi_set_max_ratio(sb->s_bdi, 1);
1025
1026         return 0;
1027 }
1028
1029 struct fuse_dev *fuse_dev_alloc(struct fuse_conn *fc)
1030 {
1031         struct fuse_dev *fud;
1032
1033         fud = kzalloc(sizeof(struct fuse_dev), GFP_KERNEL);
1034         if (fud) {
1035                 fud->fc = fuse_conn_get(fc);
1036                 fuse_pqueue_init(&fud->pq);
1037
1038                 spin_lock(&fc->lock);
1039                 list_add_tail(&fud->entry, &fc->devices);
1040                 spin_unlock(&fc->lock);
1041         }
1042
1043         return fud;
1044 }
1045 EXPORT_SYMBOL_GPL(fuse_dev_alloc);
1046
1047 void fuse_dev_free(struct fuse_dev *fud)
1048 {
1049         struct fuse_conn *fc = fud->fc;
1050
1051         if (fc) {
1052                 spin_lock(&fc->lock);
1053                 list_del(&fud->entry);
1054                 spin_unlock(&fc->lock);
1055
1056                 fuse_conn_put(fc);
1057         }
1058         kfree(fud);
1059 }
1060 EXPORT_SYMBOL_GPL(fuse_dev_free);
1061
1062 static int fuse_fill_super(struct super_block *sb, void *data, int silent)
1063 {
1064         struct fuse_dev *fud;
1065         struct fuse_conn *fc;
1066         struct inode *root;
1067         struct fuse_mount_data d;
1068         struct file *file;
1069         struct dentry *root_dentry;
1070         struct fuse_req *init_req;
1071         int err;
1072         int is_bdev = sb->s_bdev != NULL;
1073
1074         err = -EINVAL;
1075         if (sb->s_flags & SB_MANDLOCK)
1076                 goto err;
1077
1078         sb->s_flags &= ~(SB_NOSEC | SB_I_VERSION);
1079
1080         if (!parse_fuse_opt(data, &d, is_bdev, sb->s_user_ns))
1081                 goto err;
1082
1083         if (is_bdev) {
1084 #ifdef CONFIG_BLOCK
1085                 err = -EINVAL;
1086                 if (!sb_set_blocksize(sb, d.blksize))
1087                         goto err;
1088 #endif
1089         } else {
1090                 sb->s_blocksize = PAGE_SIZE;
1091                 sb->s_blocksize_bits = PAGE_SHIFT;
1092         }
1093         sb->s_magic = FUSE_SUPER_MAGIC;
1094         sb->s_op = &fuse_super_operations;
1095         sb->s_xattr = fuse_xattr_handlers;
1096         sb->s_maxbytes = MAX_LFS_FILESIZE;
1097         sb->s_time_gran = 1;
1098         sb->s_export_op = &fuse_export_operations;
1099         sb->s_iflags |= SB_I_IMA_UNVERIFIABLE_SIGNATURE;
1100         if (sb->s_user_ns != &init_user_ns)
1101                 sb->s_iflags |= SB_I_UNTRUSTED_MOUNTER;
1102
1103         file = fget(d.fd);
1104         err = -EINVAL;
1105         if (!file)
1106                 goto err;
1107
1108         /*
1109          * Require mount to happen from the same user namespace which
1110          * opened /dev/fuse to prevent potential attacks.
1111          */
1112         if (file->f_op != &fuse_dev_operations ||
1113             file->f_cred->user_ns != sb->s_user_ns)
1114                 goto err_fput;
1115
1116         /*
1117          * If we are not in the initial user namespace posix
1118          * acls must be translated.
1119          */
1120         if (sb->s_user_ns != &init_user_ns)
1121                 sb->s_xattr = fuse_no_acl_xattr_handlers;
1122
1123         fc = kmalloc(sizeof(*fc), GFP_KERNEL);
1124         err = -ENOMEM;
1125         if (!fc)
1126                 goto err_fput;
1127
1128         fuse_conn_init(fc, sb->s_user_ns);
1129         fc->release = fuse_free_conn;
1130
1131         fud = fuse_dev_alloc(fc);
1132         if (!fud)
1133                 goto err_put_conn;
1134
1135         fc->dev = sb->s_dev;
1136         fc->sb = sb;
1137         err = fuse_bdi_init(fc, sb);
1138         if (err)
1139                 goto err_dev_free;
1140
1141         /* Handle umasking inside the fuse code */
1142         if (sb->s_flags & SB_POSIXACL)
1143                 fc->dont_mask = 1;
1144         sb->s_flags |= SB_POSIXACL;
1145
1146         fc->default_permissions = d.default_permissions;
1147         fc->allow_other = d.allow_other;
1148         fc->user_id = d.user_id;
1149         fc->group_id = d.group_id;
1150         fc->max_read = max_t(unsigned, 4096, d.max_read);
1151
1152         /* Used by get_root_inode() */
1153         sb->s_fs_info = fc;
1154
1155         err = -ENOMEM;
1156         root = fuse_get_root_inode(sb, d.rootmode);
1157         sb->s_d_op = &fuse_root_dentry_operations;
1158         root_dentry = d_make_root(root);
1159         if (!root_dentry)
1160                 goto err_dev_free;
1161         /* Root dentry doesn't have .d_revalidate */
1162         sb->s_d_op = &fuse_dentry_operations;
1163
1164         init_req = fuse_request_alloc(0);
1165         if (!init_req)
1166                 goto err_put_root;
1167         __set_bit(FR_BACKGROUND, &init_req->flags);
1168
1169         if (is_bdev) {
1170                 fc->destroy_req = fuse_request_alloc(0);
1171                 if (!fc->destroy_req)
1172                         goto err_free_init_req;
1173         }
1174
1175         mutex_lock(&fuse_mutex);
1176         err = -EINVAL;
1177         if (file->private_data)
1178                 goto err_unlock;
1179
1180         err = fuse_ctl_add_conn(fc);
1181         if (err)
1182                 goto err_unlock;
1183
1184         list_add_tail(&fc->entry, &fuse_conn_list);
1185         sb->s_root = root_dentry;
1186         file->private_data = fud;
1187         mutex_unlock(&fuse_mutex);
1188         /*
1189          * atomic_dec_and_test() in fput() provides the necessary
1190          * memory barrier for file->private_data to be visible on all
1191          * CPUs after this
1192          */
1193         fput(file);
1194
1195         fuse_send_init(fc, init_req);
1196
1197         return 0;
1198
1199  err_unlock:
1200         mutex_unlock(&fuse_mutex);
1201  err_free_init_req:
1202         fuse_request_free(init_req);
1203  err_put_root:
1204         dput(root_dentry);
1205  err_dev_free:
1206         fuse_dev_free(fud);
1207  err_put_conn:
1208         fuse_conn_put(fc);
1209         sb->s_fs_info = NULL;
1210  err_fput:
1211         fput(file);
1212  err:
1213         return err;
1214 }
1215
1216 static struct dentry *fuse_mount(struct file_system_type *fs_type,
1217                        int flags, const char *dev_name,
1218                        void *raw_data)
1219 {
1220         return mount_nodev(fs_type, flags, raw_data, fuse_fill_super);
1221 }
1222
1223 static void fuse_sb_destroy(struct super_block *sb)
1224 {
1225         struct fuse_conn *fc = get_fuse_conn_super(sb);
1226
1227         if (fc) {
1228                 fuse_send_destroy(fc);
1229
1230                 fuse_abort_conn(fc, false);
1231                 fuse_wait_aborted(fc);
1232
1233                 down_write(&fc->killsb);
1234                 fc->sb = NULL;
1235                 up_write(&fc->killsb);
1236         }
1237 }
1238
1239 static void fuse_kill_sb_anon(struct super_block *sb)
1240 {
1241         fuse_sb_destroy(sb);
1242         kill_anon_super(sb);
1243 }
1244
1245 static struct file_system_type fuse_fs_type = {
1246         .owner          = THIS_MODULE,
1247         .name           = "fuse",
1248         .fs_flags       = FS_HAS_SUBTYPE | FS_USERNS_MOUNT,
1249         .mount          = fuse_mount,
1250         .kill_sb        = fuse_kill_sb_anon,
1251 };
1252 MODULE_ALIAS_FS("fuse");
1253
1254 #ifdef CONFIG_BLOCK
1255 static struct dentry *fuse_mount_blk(struct file_system_type *fs_type,
1256                            int flags, const char *dev_name,
1257                            void *raw_data)
1258 {
1259         return mount_bdev(fs_type, flags, dev_name, raw_data, fuse_fill_super);
1260 }
1261
1262 static void fuse_kill_sb_blk(struct super_block *sb)
1263 {
1264         fuse_sb_destroy(sb);
1265         kill_block_super(sb);
1266 }
1267
1268 static struct file_system_type fuseblk_fs_type = {
1269         .owner          = THIS_MODULE,
1270         .name           = "fuseblk",
1271         .mount          = fuse_mount_blk,
1272         .kill_sb        = fuse_kill_sb_blk,
1273         .fs_flags       = FS_REQUIRES_DEV | FS_HAS_SUBTYPE,
1274 };
1275 MODULE_ALIAS_FS("fuseblk");
1276
1277 static inline int register_fuseblk(void)
1278 {
1279         return register_filesystem(&fuseblk_fs_type);
1280 }
1281
1282 static inline void unregister_fuseblk(void)
1283 {
1284         unregister_filesystem(&fuseblk_fs_type);
1285 }
1286 #else
1287 static inline int register_fuseblk(void)
1288 {
1289         return 0;
1290 }
1291
1292 static inline void unregister_fuseblk(void)
1293 {
1294 }
1295 #endif
1296
1297 static void fuse_inode_init_once(void *foo)
1298 {
1299         struct inode *inode = foo;
1300
1301         inode_init_once(inode);
1302 }
1303
1304 static int __init fuse_fs_init(void)
1305 {
1306         int err;
1307
1308         fuse_inode_cachep = kmem_cache_create("fuse_inode",
1309                         sizeof(struct fuse_inode), 0,
1310                         SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT|SLAB_RECLAIM_ACCOUNT,
1311                         fuse_inode_init_once);
1312         err = -ENOMEM;
1313         if (!fuse_inode_cachep)
1314                 goto out;
1315
1316         err = register_fuseblk();
1317         if (err)
1318                 goto out2;
1319
1320         err = register_filesystem(&fuse_fs_type);
1321         if (err)
1322                 goto out3;
1323
1324         return 0;
1325
1326  out3:
1327         unregister_fuseblk();
1328  out2:
1329         kmem_cache_destroy(fuse_inode_cachep);
1330  out:
1331         return err;
1332 }
1333
1334 static void fuse_fs_cleanup(void)
1335 {
1336         unregister_filesystem(&fuse_fs_type);
1337         unregister_fuseblk();
1338
1339         /*
1340          * Make sure all delayed rcu free inodes are flushed before we
1341          * destroy cache.
1342          */
1343         rcu_barrier();
1344         kmem_cache_destroy(fuse_inode_cachep);
1345 }
1346
1347 static struct kobject *fuse_kobj;
1348
1349 static int fuse_sysfs_init(void)
1350 {
1351         int err;
1352
1353         fuse_kobj = kobject_create_and_add("fuse", fs_kobj);
1354         if (!fuse_kobj) {
1355                 err = -ENOMEM;
1356                 goto out_err;
1357         }
1358
1359         err = sysfs_create_mount_point(fuse_kobj, "connections");
1360         if (err)
1361                 goto out_fuse_unregister;
1362
1363         return 0;
1364
1365  out_fuse_unregister:
1366         kobject_put(fuse_kobj);
1367  out_err:
1368         return err;
1369 }
1370
1371 static void fuse_sysfs_cleanup(void)
1372 {
1373         sysfs_remove_mount_point(fuse_kobj, "connections");
1374         kobject_put(fuse_kobj);
1375 }
1376
1377 static int __init fuse_init(void)
1378 {
1379         int res;
1380
1381         printk(KERN_INFO "fuse init (API version %i.%i)\n",
1382                FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);
1383
1384         INIT_LIST_HEAD(&fuse_conn_list);
1385         res = fuse_fs_init();
1386         if (res)
1387                 goto err;
1388
1389         res = fuse_dev_init();
1390         if (res)
1391                 goto err_fs_cleanup;
1392
1393         res = fuse_sysfs_init();
1394         if (res)
1395                 goto err_dev_cleanup;
1396
1397         res = fuse_ctl_init();
1398         if (res)
1399                 goto err_sysfs_cleanup;
1400
1401         sanitize_global_limit(&max_user_bgreq);
1402         sanitize_global_limit(&max_user_congthresh);
1403
1404         return 0;
1405
1406  err_sysfs_cleanup:
1407         fuse_sysfs_cleanup();
1408  err_dev_cleanup:
1409         fuse_dev_cleanup();
1410  err_fs_cleanup:
1411         fuse_fs_cleanup();
1412  err:
1413         return res;
1414 }
1415
1416 static void __exit fuse_exit(void)
1417 {
1418         printk(KERN_DEBUG "fuse exit\n");
1419
1420         fuse_ctl_cleanup();
1421         fuse_sysfs_cleanup();
1422         fuse_fs_cleanup();
1423         fuse_dev_cleanup();
1424 }
1425
1426 module_init(fuse_init);
1427 module_exit(fuse_exit);