fs/fuse/inode.c

   1 /*
   2   FUSE: Filesystem in Userspace
   3   Copyright (C) 2001-2008  Miklos Szeredi <[email protected]>
   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/fs_context.h>
  19 #include <linux/fs_parser.h>
  20 #include <linux/statfs.h>
  21 #include <linux/random.h>
  22 #include <linux/sched.h>
  23 #include <linux/exportfs.h>
  24 #include <linux/posix_acl.h>
  25 #include <linux/pid_namespace.h>
  26
  27 MODULE_AUTHOR("Miklos Szeredi <[email protected]>");
  28 MODULE_DESCRIPTION("Filesystem in Userspace");
  29 MODULE_LICENSE("GPL");
  30
  31 static struct kmem_cache *fuse_inode_cachep;
  32 struct list_head fuse_conn_list;
  33 DEFINE_MUTEX(fuse_mutex);
  34
  35 static int set_global_limit(const char *val, const struct kernel_param *kp);
  36
  37 unsigned max_user_bgreq;
  38 module_param_call(max_user_bgreq, set_global_limit, param_get_uint,
  39                   &max_user_bgreq, 0644);
  40 __MODULE_PARM_TYPE(max_user_bgreq, "uint");
  41 MODULE_PARM_DESC(max_user_bgreq,
  42  "Global limit for the maximum number of backgrounded requests an "
  43  "unprivileged user can set");
  44
  45 unsigned max_user_congthresh;
  46 module_param_call(max_user_congthresh, set_global_limit, param_get_uint,
  47                   &max_user_congthresh, 0644);
  48 __MODULE_PARM_TYPE(max_user_congthresh, "uint");
  49 MODULE_PARM_DESC(max_user_congthresh,
  50  "Global limit for the maximum congestion threshold an "
  51  "unprivileged user can set");
  52
  53 #define FUSE_SUPER_MAGIC 0x65735546
  54
  55 #define FUSE_DEFAULT_BLKSIZE 512
  56
  57 /** Maximum number of outstanding background requests */
  58 #define FUSE_DEFAULT_MAX_BACKGROUND 12
  59
  60 /** Congestion starts at 75% of maximum */
  61 #define FUSE_DEFAULT_CONGESTION_THRESHOLD (FUSE_DEFAULT_MAX_BACKGROUND * 3 / 4)
  62
  63 #ifdef CONFIG_BLOCK
  64 static struct file_system_type fuseblk_fs_type;
  65 #endif
  66
  67 struct fuse_forget_link *fuse_alloc_forget(void)
  68 {
  69         return kzalloc(sizeof(struct fuse_forget_link), GFP_KERNEL_ACCOUNT);
  70 }
  71
  72 static struct inode *fuse_alloc_inode(struct super_block *sb)
  73 {
  74         struct fuse_inode *fi;
  75
  76         fi = kmem_cache_alloc(fuse_inode_cachep, GFP_KERNEL);
  77         if (!fi)
  78                 return NULL;
  79
  80         fi->i_time = 0;
  81         fi->inval_mask = 0;
  82         fi->nodeid = 0;
  83         fi->nlookup = 0;
  84         fi->attr_version = 0;
  85         fi->orig_ino = 0;
  86         fi->state = 0;
  87         mutex_init(&fi->mutex);
  88         spin_lock_init(&fi->lock);
  89         fi->forget = fuse_alloc_forget();
  90         if (!fi->forget)
  91                 goto out_free;
  92
  93         if (IS_ENABLED(CONFIG_FUSE_DAX) && !fuse_dax_inode_alloc(sb, fi))
  94                 goto out_free_forget;
  95
  96         return &fi->inode;
  97
  98 out_free_forget:
  99         kfree(fi->forget);
 100 out_free:
 101         kmem_cache_free(fuse_inode_cachep, fi);
 102         return NULL;
 103 }
 104
 105 static void fuse_free_inode(struct inode *inode)
 106 {
 107         struct fuse_inode *fi = get_fuse_inode(inode);
 108
 109         mutex_destroy(&fi->mutex);
 110         kfree(fi->forget);
 111 #ifdef CONFIG_FUSE_DAX
 112         kfree(fi->dax);
 113 #endif
 114         kmem_cache_free(fuse_inode_cachep, fi);
 115 }
 116
 117 static void fuse_evict_inode(struct inode *inode)
 118 {
 119         struct fuse_inode *fi = get_fuse_inode(inode);
 120
 121         /* Will write inode on close/munmap and in all other dirtiers */
 122         WARN_ON(inode->i_state & I_DIRTY_INODE);
 123
 124         truncate_inode_pages_final(&inode->i_data);
 125         clear_inode(inode);
 126         if (inode->i_sb->s_flags & SB_ACTIVE) {
 127                 struct fuse_conn *fc = get_fuse_conn(inode);
 128
 129                 if (FUSE_IS_DAX(inode))
 130                         fuse_dax_inode_cleanup(inode);
 131                 if (fi->nlookup) {
 132                         fuse_queue_forget(fc, fi->forget, fi->nodeid,
 133                                           fi->nlookup);
 134                         fi->forget = NULL;
 135                 }
 136         }
 137         if (S_ISREG(inode->i_mode) && !fuse_is_bad(inode)) {
 138                 WARN_ON(!list_empty(&fi->write_files));
 139                 WARN_ON(!list_empty(&fi->queued_writes));
 140         }
 141 }
 142
 143 static int fuse_reconfigure(struct fs_context *fsc)
 144 {
 145         struct super_block *sb = fsc->root->d_sb;
 146
 147         sync_filesystem(sb);
 148         if (fsc->sb_flags & SB_MANDLOCK)
 149                 return -EINVAL;
 150
 151         return 0;
 152 }
 153
 154 /*
 155  * ino_t is 32-bits on 32-bit arch. We have to squash the 64-bit value down
 156  * so that it will fit.
 157  */
 158 static ino_t fuse_squash_ino(u64 ino64)
 159 {
 160         ino_t ino = (ino_t) ino64;
 161         if (sizeof(ino_t) < sizeof(u64))
 162                 ino ^= ino64 >> (sizeof(u64) - sizeof(ino_t)) * 8;
 163         return ino;
 164 }
 165
 166 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
 167                                    u64 attr_valid, u32 cache_mask)
 168 {
 169         struct fuse_conn *fc = get_fuse_conn(inode);
 170         struct fuse_inode *fi = get_fuse_inode(inode);
 171
 172         lockdep_assert_held(&fi->lock);
 173
 174         fi->attr_version = atomic64_inc_return(&fc->attr_version);
 175         fi->i_time = attr_valid;
 176         WRITE_ONCE(fi->inval_mask, 0);
 177
 178         inode->i_ino     = fuse_squash_ino(attr->ino);
 179         inode->i_mode    = (inode->i_mode & S_IFMT) | (attr->mode & 07777);
 180         set_nlink(inode, attr->nlink);
 181         inode->i_uid     = make_kuid(fc->user_ns, attr->uid);
 182         inode->i_gid     = make_kgid(fc->user_ns, attr->gid);
 183         inode->i_blocks  = attr->blocks;
 184         inode->i_atime.tv_sec   = attr->atime;
 185         inode->i_atime.tv_nsec  = attr->atimensec;
 186         /* mtime from server may be stale due to local buffered write */
 187         if (!(cache_mask & STATX_MTIME)) {
 188                 inode->i_mtime.tv_sec   = attr->mtime;
 189                 inode->i_mtime.tv_nsec  = attr->mtimensec;
 190         }
 191         if (!(cache_mask & STATX_CTIME)) {
 192                 inode->i_ctime.tv_sec   = attr->ctime;
 193                 inode->i_ctime.tv_nsec  = attr->ctimensec;
 194         }
 195
 196         if (attr->blksize != 0)
 197                 inode->i_blkbits = ilog2(attr->blksize);
 198         else
 199                 inode->i_blkbits = inode->i_sb->s_blocksize_bits;
 200
 201         /*
 202          * Don't set the sticky bit in i_mode, unless we want the VFS
 203          * to check permissions.  This prevents failures due to the
 204          * check in may_delete().
 205          */
 206         fi->orig_i_mode = inode->i_mode;
 207         if (!fc->default_permissions)
 208                 inode->i_mode &= ~S_ISVTX;
 209
 210         fi->orig_ino = attr->ino;
 211
 212         /*
 213          * We are refreshing inode data and it is possible that another
 214          * client set suid/sgid or security.capability xattr. So clear
 215          * S_NOSEC. Ideally, we could have cleared it only if suid/sgid
 216          * was set or if security.capability xattr was set. But we don't
 217          * know if security.capability has been set or not. So clear it
 218          * anyway. Its less efficient but should be safe.
 219          */
 220         inode->i_flags &= ~S_NOSEC;
 221 }
 222
 223 u32 fuse_get_cache_mask(struct inode *inode)
 224 {
 225         struct fuse_conn *fc = get_fuse_conn(inode);
 226
 227         if (!fc->writeback_cache || !S_ISREG(inode->i_mode))
 228                 return 0;
 229
 230         return STATX_MTIME | STATX_CTIME | STATX_SIZE;
 231 }
 232
 233 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
 234                             u64 attr_valid, u64 attr_version)
 235 {
 236         struct fuse_conn *fc = get_fuse_conn(inode);
 237         struct fuse_inode *fi = get_fuse_inode(inode);
 238         u32 cache_mask;
 239         loff_t oldsize;
 240         struct timespec64 old_mtime;
 241
 242         spin_lock(&fi->lock);
 243         /*
 244          * In case of writeback_cache enabled, writes update mtime, ctime and
 245          * may update i_size.  In these cases trust the cached value in the
 246          * inode.
 247          */
 248         cache_mask = fuse_get_cache_mask(inode);
 249         if (cache_mask & STATX_SIZE)
 250                 attr->size = i_size_read(inode);
 251
 252         if (cache_mask & STATX_MTIME) {
 253                 attr->mtime = inode->i_mtime.tv_sec;
 254                 attr->mtimensec = inode->i_mtime.tv_nsec;
 255         }
 256         if (cache_mask & STATX_CTIME) {
 257                 attr->ctime = inode->i_ctime.tv_sec;
 258                 attr->ctimensec = inode->i_ctime.tv_nsec;
 259         }
 260
 261         if ((attr_version != 0 && fi->attr_version > attr_version) ||
 262             test_bit(FUSE_I_SIZE_UNSTABLE, &fi->state)) {
 263                 spin_unlock(&fi->lock);
 264                 return;
 265         }
 266
 267         old_mtime = inode->i_mtime;
 268         fuse_change_attributes_common(inode, attr, attr_valid, cache_mask);
 269
 270         oldsize = inode->i_size;
 271         /*
 272          * In case of writeback_cache enabled, the cached writes beyond EOF
 273          * extend local i_size without keeping userspace server in sync. So,
 274          * attr->size coming from server can be stale. We cannot trust it.
 275          */
 276         if (!(cache_mask & STATX_SIZE))
 277                 i_size_write(inode, attr->size);
 278         spin_unlock(&fi->lock);
 279
 280         if (!cache_mask && S_ISREG(inode->i_mode)) {
 281                 bool inval = false;
 282
 283                 if (oldsize != attr->size) {
 284                         truncate_pagecache(inode, attr->size);
 285                         if (!fc->explicit_inval_data)
 286                                 inval = true;
 287                 } else if (fc->auto_inval_data) {
 288                         struct timespec64 new_mtime = {
 289                                 .tv_sec = attr->mtime,
 290                                 .tv_nsec = attr->mtimensec,
 291                         };
 292
 293                         /*
 294                          * Auto inval mode also checks and invalidates if mtime
 295                          * has changed.
 296                          */
 297                         if (!timespec64_equal(&old_mtime, &new_mtime))
 298                                 inval = true;
 299                 }
 300
 301                 if (inval)
 302                         invalidate_inode_pages2(inode->i_mapping);
 303         }
 304 }
 305
 306 static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr)
 307 {
 308         inode->i_mode = attr->mode & S_IFMT;
 309         inode->i_size = attr->size;
 310         inode->i_mtime.tv_sec  = attr->mtime;
 311         inode->i_mtime.tv_nsec = attr->mtimensec;
 312         inode->i_ctime.tv_sec  = attr->ctime;
 313         inode->i_ctime.tv_nsec = attr->ctimensec;
 314         if (S_ISREG(inode->i_mode)) {
 315                 fuse_init_common(inode);
 316                 fuse_init_file_inode(inode);
 317         } else if (S_ISDIR(inode->i_mode))
 318                 fuse_init_dir(inode);
 319         else if (S_ISLNK(inode->i_mode))
 320                 fuse_init_symlink(inode);
 321         else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
 322                  S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
 323                 fuse_init_common(inode);
 324                 init_special_inode(inode, inode->i_mode,
 325                                    new_decode_dev(attr->rdev));
 326         } else
 327                 BUG();
 328 }
 329
 330 static int fuse_inode_eq(struct inode *inode, void *_nodeidp)
 331 {
 332         u64 nodeid = *(u64 *) _nodeidp;
 333         if (get_node_id(inode) == nodeid)
 334                 return 1;
 335         else
 336                 return 0;
 337 }
 338
 339 static int fuse_inode_set(struct inode *inode, void *_nodeidp)
 340 {
 341         u64 nodeid = *(u64 *) _nodeidp;
 342         get_fuse_inode(inode)->nodeid = nodeid;
 343         return 0;
 344 }
 345
 346 struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
 347                         int generation, struct fuse_attr *attr,
 348                         u64 attr_valid, u64 attr_version)
 349 {
 350         struct inode *inode;
 351         struct fuse_inode *fi;
 352         struct fuse_conn *fc = get_fuse_conn_super(sb);
 353
 354         /*
 355          * Auto mount points get their node id from the submount root, which is
 356          * not a unique identifier within this filesystem.
 357          *
 358          * To avoid conflicts, do not place submount points into the inode hash
 359          * table.
 360          */
 361         if (fc->auto_submounts && (attr->flags & FUSE_ATTR_SUBMOUNT) &&
 362             S_ISDIR(attr->mode)) {
 363                 inode = new_inode(sb);
 364                 if (!inode)
 365                         return NULL;
 366
 367                 fuse_init_inode(inode, attr);
 368                 get_fuse_inode(inode)->nodeid = nodeid;
 369                 inode->i_flags |= S_AUTOMOUNT;
 370                 goto done;
 371         }
 372
 373 retry:
 374         inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid);
 375         if (!inode)
 376                 return NULL;
 377
 378         if ((inode->i_state & I_NEW)) {
 379                 inode->i_flags |= S_NOATIME;
 380                 if (!fc->writeback_cache || !S_ISREG(attr->mode))
 381                         inode->i_flags |= S_NOCMTIME;
 382                 inode->i_generation = generation;
 383                 fuse_init_inode(inode, attr);
 384                 unlock_new_inode(inode);
 385         } else if (fuse_stale_inode(inode, generation, attr)) {
 386                 /* nodeid was reused, any I/O on the old inode should fail */
 387                 fuse_make_bad(inode);
 388                 iput(inode);
 389                 goto retry;
 390         }
 391 done:
 392         fi = get_fuse_inode(inode);
 393         spin_lock(&fi->lock);
 394         fi->nlookup++;
 395         spin_unlock(&fi->lock);
 396         fuse_change_attributes(inode, attr, attr_valid, attr_version);
 397
 398         return inode;
 399 }
 400
 401 struct inode *fuse_ilookup(struct fuse_conn *fc, u64 nodeid,
 402                            struct fuse_mount **fm)
 403 {
 404         struct fuse_mount *fm_iter;
 405         struct inode *inode;
 406
 407         WARN_ON(!rwsem_is_locked(&fc->killsb));
 408         list_for_each_entry(fm_iter, &fc->mounts, fc_entry) {
 409                 if (!fm_iter->sb)
 410                         continue;
 411
 412                 inode = ilookup5(fm_iter->sb, nodeid, fuse_inode_eq, &nodeid);
 413                 if (inode) {
 414                         if (fm)
 415                                 *fm = fm_iter;
 416                         return inode;
 417                 }
 418         }
 419
 420         return NULL;
 421 }
 422
 423 int fuse_reverse_inval_inode(struct fuse_conn *fc, u64 nodeid,
 424                              loff_t offset, loff_t len)
 425 {
 426         struct fuse_inode *fi;
 427         struct inode *inode;
 428         pgoff_t pg_start;
 429         pgoff_t pg_end;
 430
 431         inode = fuse_ilookup(fc, nodeid, NULL);
 432         if (!inode)
 433                 return -ENOENT;
 434
 435         fi = get_fuse_inode(inode);
 436         spin_lock(&fi->lock);
 437         fi->attr_version = atomic64_inc_return(&fc->attr_version);
 438         spin_unlock(&fi->lock);
 439
 440         fuse_invalidate_attr(inode);
 441         forget_all_cached_acls(inode);
 442         if (offset >= 0) {
 443                 pg_start = offset >> PAGE_SHIFT;
 444                 if (len <= 0)
 445                         pg_end = -1;
 446                 else
 447                         pg_end = (offset + len - 1) >> PAGE_SHIFT;
 448                 invalidate_inode_pages2_range(inode->i_mapping,
 449                                               pg_start, pg_end);
 450         }
 451         iput(inode);
 452         return 0;
 453 }
 454
 455 bool fuse_lock_inode(struct inode *inode)
 456 {
 457         bool locked = false;
 458
 459         if (!get_fuse_conn(inode)->parallel_dirops) {
 460                 mutex_lock(&get_fuse_inode(inode)->mutex);
 461                 locked = true;
 462         }
 463
 464         return locked;
 465 }
 466
 467 void fuse_unlock_inode(struct inode *inode, bool locked)
 468 {
 469         if (locked)
 470                 mutex_unlock(&get_fuse_inode(inode)->mutex);
 471 }
 472
 473 static void fuse_umount_begin(struct super_block *sb)
 474 {
 475         struct fuse_conn *fc = get_fuse_conn_super(sb);
 476
 477         if (!fc->no_force_umount)
 478                 fuse_abort_conn(fc);
 479 }
 480
 481 static void fuse_send_destroy(struct fuse_mount *fm)
 482 {
 483         if (fm->fc->conn_init) {
 484                 FUSE_ARGS(args);
 485
 486                 args.opcode = FUSE_DESTROY;
 487                 args.force = true;
 488                 args.nocreds = true;
 489                 fuse_simple_request(fm, &args);
 490         }
 491 }
 492
 493 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr)
 494 {
 495         stbuf->f_type    = FUSE_SUPER_MAGIC;
 496         stbuf->f_bsize   = attr->bsize;
 497         stbuf->f_frsize  = attr->frsize;
 498         stbuf->f_blocks  = attr->blocks;
 499         stbuf->f_bfree   = attr->bfree;
 500         stbuf->f_bavail  = attr->bavail;
 501         stbuf->f_files   = attr->files;
 502         stbuf->f_ffree   = attr->ffree;
 503         stbuf->f_namelen = attr->namelen;
 504         /* fsid is left zero */
 505 }
 506
 507 static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf)
 508 {
 509         struct super_block *sb = dentry->d_sb;
 510         struct fuse_mount *fm = get_fuse_mount_super(sb);
 511         FUSE_ARGS(args);
 512         struct fuse_statfs_out outarg;
 513         int err;
 514
 515         if (!fuse_allow_current_process(fm->fc)) {
 516                 buf->f_type = FUSE_SUPER_MAGIC;
 517                 return 0;
 518         }
 519
 520         memset(&outarg, 0, sizeof(outarg));
 521         args.in_numargs = 0;
 522         args.opcode = FUSE_STATFS;
 523         args.nodeid = get_node_id(d_inode(dentry));
 524         args.out_numargs = 1;
 525         args.out_args[0].size = sizeof(outarg);
 526         args.out_args[0].value = &outarg;
 527         err = fuse_simple_request(fm, &args);
 528         if (!err)
 529                 convert_fuse_statfs(buf, &outarg.st);
 530         return err;
 531 }
 532
 533 static struct fuse_sync_bucket *fuse_sync_bucket_alloc(void)
 534 {
 535         struct fuse_sync_bucket *bucket;
 536
 537         bucket = kzalloc(sizeof(*bucket), GFP_KERNEL | __GFP_NOFAIL);
 538         if (bucket) {
 539                 init_waitqueue_head(&bucket->waitq);
 540                 /* Initial active count */
 541                 atomic_set(&bucket->count, 1);
 542         }
 543         return bucket;
 544 }
 545
 546 static void fuse_sync_fs_writes(struct fuse_conn *fc)
 547 {
 548         struct fuse_sync_bucket *bucket, *new_bucket;
 549         int count;
 550
 551         new_bucket = fuse_sync_bucket_alloc();
 552         spin_lock(&fc->lock);
 553         bucket = rcu_dereference_protected(fc->curr_bucket, 1);
 554         count = atomic_read(&bucket->count);
 555         WARN_ON(count < 1);
 556         /* No outstanding writes? */
 557         if (count == 1) {
 558                 spin_unlock(&fc->lock);
 559                 kfree(new_bucket);
 560                 return;
 561         }
 562
 563         /*
 564          * Completion of new bucket depends on completion of this bucket, so add
 565          * one more count.
 566          */
 567         atomic_inc(&new_bucket->count);
 568         rcu_assign_pointer(fc->curr_bucket, new_bucket);
 569         spin_unlock(&fc->lock);
 570         /*
 571          * Drop initial active count.  At this point if all writes in this and
 572          * ancestor buckets complete, the count will go to zero and this task
 573          * will be woken up.
 574          */
 575         atomic_dec(&bucket->count);
 576
 577         wait_event(bucket->waitq, atomic_read(&bucket->count) == 0);
 578
 579         /* Drop temp count on descendant bucket */
 580         fuse_sync_bucket_dec(new_bucket);
 581         kfree_rcu(bucket, rcu);
 582 }
 583
 584 static int fuse_sync_fs(struct super_block *sb, int wait)
 585 {
 586         struct fuse_mount *fm = get_fuse_mount_super(sb);
 587         struct fuse_conn *fc = fm->fc;
 588         struct fuse_syncfs_in inarg;
 589         FUSE_ARGS(args);
 590         int err;
 591
 592         /*
 593          * Userspace cannot handle the wait == 0 case.  Avoid a
 594          * gratuitous roundtrip.
 595          */
 596         if (!wait)
 597                 return 0;
 598
 599         /* The filesystem is being unmounted.  Nothing to do. */
 600         if (!sb->s_root)
 601                 return 0;
 602
 603         if (!fc->sync_fs)
 604                 return 0;
 605
 606         fuse_sync_fs_writes(fc);
 607
 608         memset(&inarg, 0, sizeof(inarg));
 609         args.in_numargs = 1;
 610         args.in_args[0].size = sizeof(inarg);
 611         args.in_args[0].value = &inarg;
 612         args.opcode = FUSE_SYNCFS;
 613         args.nodeid = get_node_id(sb->s_root->d_inode);
 614         args.out_numargs = 0;
 615
 616         err = fuse_simple_request(fm, &args);
 617         if (err == -ENOSYS) {
 618                 fc->sync_fs = 0;
 619                 err = 0;
 620         }
 621
 622         return err;
 623 }
 624
 625 enum {
 626         OPT_SOURCE,
 627         OPT_SUBTYPE,
 628         OPT_FD,
 629         OPT_ROOTMODE,
 630         OPT_USER_ID,
 631         OPT_GROUP_ID,
 632         OPT_DEFAULT_PERMISSIONS,
 633         OPT_ALLOW_OTHER,
 634         OPT_MAX_READ,
 635         OPT_BLKSIZE,
 636         OPT_ERR
 637 };
 638
 639 static const struct fs_parameter_spec fuse_fs_parameters[] = {
 640         fsparam_string  ("source",              OPT_SOURCE),
 641         fsparam_u32     ("fd",                  OPT_FD),
 642         fsparam_u32oct  ("rootmode",            OPT_ROOTMODE),
 643         fsparam_u32     ("user_id",             OPT_USER_ID),
 644         fsparam_u32     ("group_id",            OPT_GROUP_ID),
 645         fsparam_flag    ("default_permissions", OPT_DEFAULT_PERMISSIONS),
 646         fsparam_flag    ("allow_other",         OPT_ALLOW_OTHER),
 647         fsparam_u32     ("max_read",            OPT_MAX_READ),
 648         fsparam_u32     ("blksize",             OPT_BLKSIZE),
 649         fsparam_string  ("subtype",             OPT_SUBTYPE),
 650         {}
 651 };
 652
 653 static int fuse_parse_param(struct fs_context *fsc, struct fs_parameter *param)
 654 {
 655         struct fs_parse_result result;
 656         struct fuse_fs_context *ctx = fsc->fs_private;
 657         int opt;
 658
 659         if (fsc->purpose == FS_CONTEXT_FOR_RECONFIGURE) {
 660                 /*
 661                  * Ignore options coming from mount(MS_REMOUNT) for backward
 662                  * compatibility.
 663                  */
 664                 if (fsc->oldapi)
 665                         return 0;
 666
 667                 return invalfc(fsc, "No changes allowed in reconfigure");
 668         }
 669
 670         opt = fs_parse(fsc, fuse_fs_parameters, param, &result);
 671         if (opt < 0)
 672                 return opt;
 673
 674         switch (opt) {
 675         case OPT_SOURCE:
 676                 if (fsc->source)
 677                         return invalfc(fsc, "Multiple sources specified");
 678                 fsc->source = param->string;
 679                 param->string = NULL;
 680                 break;
 681
 682         case OPT_SUBTYPE:
 683                 if (ctx->subtype)
 684                         return invalfc(fsc, "Multiple subtypes specified");
 685                 ctx->subtype = param->string;
 686                 param->string = NULL;
 687                 return 0;
 688
 689         case OPT_FD:
 690                 ctx->fd = result.uint_32;
 691                 ctx->fd_present = true;
 692                 break;
 693
 694         case OPT_ROOTMODE:
 695                 if (!fuse_valid_type(result.uint_32))
 696                         return invalfc(fsc, "Invalid rootmode");
 697                 ctx->rootmode = result.uint_32;
 698                 ctx->rootmode_present = true;
 699                 break;
 700
 701         case OPT_USER_ID:
 702                 ctx->user_id = make_kuid(fsc->user_ns, result.uint_32);
 703                 if (!uid_valid(ctx->user_id))
 704                         return invalfc(fsc, "Invalid user_id");
 705                 ctx->user_id_present = true;
 706                 break;
 707
 708         case OPT_GROUP_ID:
 709                 ctx->group_id = make_kgid(fsc->user_ns, result.uint_32);
 710                 if (!gid_valid(ctx->group_id))
 711                         return invalfc(fsc, "Invalid group_id");
 712                 ctx->group_id_present = true;
 713                 break;
 714
 715         case OPT_DEFAULT_PERMISSIONS:
 716                 ctx->default_permissions = true;
 717                 break;
 718
 719         case OPT_ALLOW_OTHER:
 720                 ctx->allow_other = true;
 721                 break;
 722
 723         case OPT_MAX_READ:
 724                 ctx->max_read = result.uint_32;
 725                 break;
 726
 727         case OPT_BLKSIZE:
 728                 if (!ctx->is_bdev)
 729                         return invalfc(fsc, "blksize only supported for fuseblk");
 730                 ctx->blksize = result.uint_32;
 731                 break;
 732
 733         default:
 734                 return -EINVAL;
 735         }
 736
 737         return 0;
 738 }
 739
 740 static void fuse_free_fsc(struct fs_context *fsc)
 741 {
 742         struct fuse_fs_context *ctx = fsc->fs_private;
 743
 744         if (ctx) {
 745                 kfree(ctx->subtype);
 746                 kfree(ctx);
 747         }
 748 }
 749
 750 static int fuse_show_options(struct seq_file *m, struct dentry *root)
 751 {
 752         struct super_block *sb = root->d_sb;
 753         struct fuse_conn *fc = get_fuse_conn_super(sb);
 754
 755         if (fc->legacy_opts_show) {
 756                 seq_printf(m, ",user_id=%u",
 757                            from_kuid_munged(fc->user_ns, fc->user_id));
 758                 seq_printf(m, ",group_id=%u",
 759                            from_kgid_munged(fc->user_ns, fc->group_id));
 760                 if (fc->default_permissions)
 761                         seq_puts(m, ",default_permissions");
 762                 if (fc->allow_other)
 763                         seq_puts(m, ",allow_other");
 764                 if (fc->max_read != ~0)
 765                         seq_printf(m, ",max_read=%u", fc->max_read);
 766                 if (sb->s_bdev && sb->s_blocksize != FUSE_DEFAULT_BLKSIZE)
 767                         seq_printf(m, ",blksize=%lu", sb->s_blocksize);
 768         }
 769 #ifdef CONFIG_FUSE_DAX
 770         if (fc->dax)
 771                 seq_puts(m, ",dax");
 772 #endif
 773
 774         return 0;
 775 }
 776
 777 static void fuse_iqueue_init(struct fuse_iqueue *fiq,
 778                              const struct fuse_iqueue_ops *ops,
 779                              void *priv)
 780 {
 781         memset(fiq, 0, sizeof(struct fuse_iqueue));
 782         spin_lock_init(&fiq->lock);
 783         init_waitqueue_head(&fiq->waitq);
 784         INIT_LIST_HEAD(&fiq->pending);
 785         INIT_LIST_HEAD(&fiq->interrupts);
 786         fiq->forget_list_tail = &fiq->forget_list_head;
 787         fiq->connected = 1;
 788         fiq->ops = ops;
 789         fiq->priv = priv;
 790 }
 791
 792 static void fuse_pqueue_init(struct fuse_pqueue *fpq)
 793 {
 794         unsigned int i;
 795
 796         spin_lock_init(&fpq->lock);
 797         for (i = 0; i < FUSE_PQ_HASH_SIZE; i++)
 798                 INIT_LIST_HEAD(&fpq->processing[i]);
 799         INIT_LIST_HEAD(&fpq->io);
 800         fpq->connected = 1;
 801 }
 802
 803 void fuse_conn_init(struct fuse_conn *fc, struct fuse_mount *fm,
 804                     struct user_namespace *user_ns,
 805                     const struct fuse_iqueue_ops *fiq_ops, void *fiq_priv)
 806 {
 807         memset(fc, 0, sizeof(*fc));
 808         spin_lock_init(&fc->lock);
 809         spin_lock_init(&fc->bg_lock);
 810         init_rwsem(&fc->killsb);
 811         refcount_set(&fc->count, 1);
 812         atomic_set(&fc->dev_count, 1);
 813         init_waitqueue_head(&fc->blocked_waitq);
 814         fuse_iqueue_init(&fc->iq, fiq_ops, fiq_priv);
 815         INIT_LIST_HEAD(&fc->bg_queue);
 816         INIT_LIST_HEAD(&fc->entry);
 817         INIT_LIST_HEAD(&fc->devices);
 818         atomic_set(&fc->num_waiting, 0);
 819         fc->max_background = FUSE_DEFAULT_MAX_BACKGROUND;
 820         fc->congestion_threshold = FUSE_DEFAULT_CONGESTION_THRESHOLD;
 821         atomic64_set(&fc->khctr, 0);
 822         fc->polled_files = RB_ROOT;
 823         fc->blocked = 0;
 824         fc->initialized = 0;
 825         fc->connected = 1;
 826         atomic64_set(&fc->attr_version, 1);
 827         get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key));
 828         fc->pid_ns = get_pid_ns(task_active_pid_ns(current));
 829         fc->user_ns = get_user_ns(user_ns);
 830         fc->max_pages = FUSE_DEFAULT_MAX_PAGES_PER_REQ;
 831         fc->max_pages_limit = FUSE_MAX_MAX_PAGES;
 832
 833         INIT_LIST_HEAD(&fc->mounts);
 834         list_add(&fm->fc_entry, &fc->mounts);
 835         fm->fc = fc;
 836 }
 837 EXPORT_SYMBOL_GPL(fuse_conn_init);
 838
 839 void fuse_conn_put(struct fuse_conn *fc)
 840 {
 841         if (refcount_dec_and_test(&fc->count)) {
 842                 struct fuse_iqueue *fiq = &fc->iq;
 843                 struct fuse_sync_bucket *bucket;
 844
 845                 if (IS_ENABLED(CONFIG_FUSE_DAX))
 846                         fuse_dax_conn_free(fc);
 847                 if (fiq->ops->release)
 848                         fiq->ops->release(fiq);
 849                 put_pid_ns(fc->pid_ns);
 850                 put_user_ns(fc->user_ns);
 851                 bucket = rcu_dereference_protected(fc->curr_bucket, 1);
 852                 if (bucket) {
 853                         WARN_ON(atomic_read(&bucket->count) != 1);
 854                         kfree(bucket);
 855                 }
 856                 fc->release(fc);
 857         }
 858 }
 859 EXPORT_SYMBOL_GPL(fuse_conn_put);
 860
 861 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc)
 862 {
 863         refcount_inc(&fc->count);
 864         return fc;
 865 }
 866 EXPORT_SYMBOL_GPL(fuse_conn_get);
 867
 868 static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned mode)
 869 {
 870         struct fuse_attr attr;
 871         memset(&attr, 0, sizeof(attr));
 872
 873         attr.mode = mode;
 874         attr.ino = FUSE_ROOT_ID;
 875         attr.nlink = 1;
 876         return fuse_iget(sb, 1, 0, &attr, 0, 0);
 877 }
 878
 879 struct fuse_inode_handle {
 880         u64 nodeid;
 881         u32 generation;
 882 };
 883
 884 static struct dentry *fuse_get_dentry(struct super_block *sb,
 885                                       struct fuse_inode_handle *handle)
 886 {
 887         struct fuse_conn *fc = get_fuse_conn_super(sb);
 888         struct inode *inode;
 889         struct dentry *entry;
 890         int err = -ESTALE;
 891
 892         if (handle->nodeid == 0)
 893                 goto out_err;
 894
 895         inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid);
 896         if (!inode) {
 897                 struct fuse_entry_out outarg;
 898                 const struct qstr name = QSTR_INIT(".", 1);
 899
 900                 if (!fc->export_support)
 901                         goto out_err;
 902
 903                 err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg,
 904                                        &inode);
 905                 if (err && err != -ENOENT)
 906                         goto out_err;
 907                 if (err || !inode) {
 908                         err = -ESTALE;
 909                         goto out_err;
 910                 }
 911                 err = -EIO;
 912                 if (get_node_id(inode) != handle->nodeid)
 913                         goto out_iput;
 914         }
 915         err = -ESTALE;
 916         if (inode->i_generation != handle->generation)
 917                 goto out_iput;
 918
 919         entry = d_obtain_alias(inode);
 920         if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID)
 921                 fuse_invalidate_entry_cache(entry);
 922
 923         return entry;
 924
 925  out_iput:
 926         iput(inode);
 927  out_err:
 928         return ERR_PTR(err);
 929 }
 930
 931 static int fuse_encode_fh(struct inode *inode, u32 *fh, int *max_len,
 932                            struct inode *parent)
 933 {
 934         int len = parent ? 6 : 3;
 935         u64 nodeid;
 936         u32 generation;
 937
 938         if (*max_len < len) {
 939                 *max_len = len;
 940                 return  FILEID_INVALID;
 941         }
 942
 943         nodeid = get_fuse_inode(inode)->nodeid;
 944         generation = inode->i_generation;
 945
 946         fh[0] = (u32)(nodeid >> 32);
 947         fh[1] = (u32)(nodeid & 0xffffffff);
 948         fh[2] = generation;
 949
 950         if (parent) {
 951                 nodeid = get_fuse_inode(parent)->nodeid;
 952                 generation = parent->i_generation;
 953
 954                 fh[3] = (u32)(nodeid >> 32);
 955                 fh[4] = (u32)(nodeid & 0xffffffff);
 956                 fh[5] = generation;
 957         }
 958
 959         *max_len = len;
 960         return parent ? 0x82 : 0x81;
 961 }
 962
 963 static struct dentry *fuse_fh_to_dentry(struct super_block *sb,
 964                 struct fid *fid, int fh_len, int fh_type)
 965 {
 966         struct fuse_inode_handle handle;
 967
 968         if ((fh_type != 0x81 && fh_type != 0x82) || fh_len < 3)
 969                 return NULL;
 970
 971         handle.nodeid = (u64) fid->raw[0] << 32;
 972         handle.nodeid |= (u64) fid->raw[1];
 973         handle.generation = fid->raw[2];
 974         return fuse_get_dentry(sb, &handle);
 975 }
 976
 977 static struct dentry *fuse_fh_to_parent(struct super_block *sb,
 978                 struct fid *fid, int fh_len, int fh_type)
 979 {
 980         struct fuse_inode_handle parent;
 981
 982         if (fh_type != 0x82 || fh_len < 6)
 983                 return NULL;
 984
 985         parent.nodeid = (u64) fid->raw[3] << 32;
 986         parent.nodeid |= (u64) fid->raw[4];
 987         parent.generation = fid->raw[5];
 988         return fuse_get_dentry(sb, &parent);
 989 }
 990
 991 static struct dentry *fuse_get_parent(struct dentry *child)
 992 {
 993         struct inode *child_inode = d_inode(child);
 994         struct fuse_conn *fc = get_fuse_conn(child_inode);
 995         struct inode *inode;
 996         struct dentry *parent;
 997         struct fuse_entry_out outarg;
 998         int err;
 999
1000         if (!fc->export_support)
1001                 return ERR_PTR(-ESTALE);
1002
1003         err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode),
1004                                &dotdot_name, &outarg, &inode);
1005         if (err) {
1006                 if (err == -ENOENT)
1007                         return ERR_PTR(-ESTALE);
1008                 return ERR_PTR(err);
1009         }
1010
1011         parent = d_obtain_alias(inode);
1012         if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID)
1013                 fuse_invalidate_entry_cache(parent);
1014
1015         return parent;
1016 }
1017
1018 static const struct export_operations fuse_export_operations = {
1019         .fh_to_dentry   = fuse_fh_to_dentry,
1020         .fh_to_parent   = fuse_fh_to_parent,
1021         .encode_fh      = fuse_encode_fh,
1022         .get_parent     = fuse_get_parent,
1023 };
1024
1025 static const struct super_operations fuse_super_operations = {
1026         .alloc_inode    = fuse_alloc_inode,
1027         .free_inode     = fuse_free_inode,
1028         .evict_inode    = fuse_evict_inode,
1029         .write_inode    = fuse_write_inode,
1030         .drop_inode     = generic_delete_inode,
1031         .umount_begin   = fuse_umount_begin,
1032         .statfs         = fuse_statfs,
1033         .sync_fs        = fuse_sync_fs,
1034         .show_options   = fuse_show_options,
1035 };
1036
1037 static void sanitize_global_limit(unsigned *limit)
1038 {
1039         /*
1040          * The default maximum number of async requests is calculated to consume
1041          * 1/2^13 of the total memory, assuming 392 bytes per request.
1042          */
1043         if (*limit == 0)
1044                 *limit = ((totalram_pages() << PAGE_SHIFT) >> 13) / 392;
1045
1046         if (*limit >= 1 << 16)
1047                 *limit = (1 << 16) - 1;
1048 }
1049
1050 static int set_global_limit(const char *val, const struct kernel_param *kp)
1051 {
1052         int rv;
1053
1054         rv = param_set_uint(val, kp);
1055         if (rv)
1056                 return rv;
1057
1058         sanitize_global_limit((unsigned *)kp->arg);
1059
1060         return 0;
1061 }
1062
1063 static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg)
1064 {
1065         int cap_sys_admin = capable(CAP_SYS_ADMIN);
1066
1067         if (arg->minor < 13)
1068                 return;
1069
1070         sanitize_global_limit(&max_user_bgreq);
1071         sanitize_global_limit(&max_user_congthresh);
1072
1073         spin_lock(&fc->bg_lock);
1074         if (arg->max_background) {
1075                 fc->max_background = arg->max_background;
1076
1077                 if (!cap_sys_admin && fc->max_background > max_user_bgreq)
1078                         fc->max_background = max_user_bgreq;
1079         }
1080         if (arg->congestion_threshold) {
1081                 fc->congestion_threshold = arg->congestion_threshold;
1082
1083                 if (!cap_sys_admin &&
1084                     fc->congestion_threshold > max_user_congthresh)
1085                         fc->congestion_threshold = max_user_congthresh;
1086         }
1087         spin_unlock(&fc->bg_lock);
1088 }
1089
1090 struct fuse_init_args {
1091         struct fuse_args args;
1092         struct fuse_init_in in;
1093         struct fuse_init_out out;
1094 };
1095
1096 static void process_init_reply(struct fuse_mount *fm, struct fuse_args *args,
1097                                int error)
1098 {
1099         struct fuse_conn *fc = fm->fc;
1100         struct fuse_init_args *ia = container_of(args, typeof(*ia), args);
1101         struct fuse_init_out *arg = &ia->out;
1102         bool ok = true;
1103
1104         if (error || arg->major != FUSE_KERNEL_VERSION)
1105                 ok = false;
1106         else {
1107                 unsigned long ra_pages;
1108
1109                 process_init_limits(fc, arg);
1110
1111                 if (arg->minor >= 6) {
1112                         ra_pages = arg->max_readahead / PAGE_SIZE;
1113                         if (arg->flags & FUSE_ASYNC_READ)
1114                                 fc->async_read = 1;
1115                         if (!(arg->flags & FUSE_POSIX_LOCKS))
1116                                 fc->no_lock = 1;
1117                         if (arg->minor >= 17) {
1118                                 if (!(arg->flags & FUSE_FLOCK_LOCKS))
1119                                         fc->no_flock = 1;
1120                         } else {
1121                                 if (!(arg->flags & FUSE_POSIX_LOCKS))
1122                                         fc->no_flock = 1;
1123                         }
1124                         if (arg->flags & FUSE_ATOMIC_O_TRUNC)
1125                                 fc->atomic_o_trunc = 1;
1126                         if (arg->minor >= 9) {
1127                                 /* LOOKUP has dependency on proto version */
1128                                 if (arg->flags & FUSE_EXPORT_SUPPORT)
1129                                         fc->export_support = 1;
1130                         }
1131                         if (arg->flags & FUSE_BIG_WRITES)
1132                                 fc->big_writes = 1;
1133                         if (arg->flags & FUSE_DONT_MASK)
1134                                 fc->dont_mask = 1;
1135                         if (arg->flags & FUSE_AUTO_INVAL_DATA)
1136                                 fc->auto_inval_data = 1;
1137                         else if (arg->flags & FUSE_EXPLICIT_INVAL_DATA)
1138                                 fc->explicit_inval_data = 1;
1139                         if (arg->flags & FUSE_DO_READDIRPLUS) {
1140                                 fc->do_readdirplus = 1;
1141                                 if (arg->flags & FUSE_READDIRPLUS_AUTO)
1142                                         fc->readdirplus_auto = 1;
1143                         }
1144                         if (arg->flags & FUSE_ASYNC_DIO)
1145                                 fc->async_dio = 1;
1146                         if (arg->flags & FUSE_WRITEBACK_CACHE)
1147                                 fc->writeback_cache = 1;
1148                         if (arg->flags & FUSE_PARALLEL_DIROPS)
1149                                 fc->parallel_dirops = 1;
1150                         if (arg->flags & FUSE_HANDLE_KILLPRIV)
1151                                 fc->handle_killpriv = 1;
1152                         if (arg->time_gran && arg->time_gran <= 1000000000)
1153                                 fm->sb->s_time_gran = arg->time_gran;
1154                         if ((arg->flags & FUSE_POSIX_ACL)) {
1155                                 fc->default_permissions = 1;
1156                                 fc->posix_acl = 1;
1157                                 fm->sb->s_xattr = fuse_acl_xattr_handlers;
1158                         }
1159                         if (arg->flags & FUSE_CACHE_SYMLINKS)
1160                                 fc->cache_symlinks = 1;
1161                         if (arg->flags & FUSE_ABORT_ERROR)
1162                                 fc->abort_err = 1;
1163                         if (arg->flags & FUSE_MAX_PAGES) {
1164                                 fc->max_pages =
1165                                         min_t(unsigned int, fc->max_pages_limit,
1166                                         max_t(unsigned int, arg->max_pages, 1));
1167                         }
1168                         if (IS_ENABLED(CONFIG_FUSE_DAX) &&
1169                             arg->flags & FUSE_MAP_ALIGNMENT &&
1170                             !fuse_dax_check_alignment(fc, arg->map_alignment)) {
1171                                 ok = false;
1172                         }
1173                         if (arg->flags & FUSE_HANDLE_KILLPRIV_V2) {
1174                                 fc->handle_killpriv_v2 = 1;
1175                                 fm->sb->s_flags |= SB_NOSEC;
1176                         }
1177                         if (arg->flags & FUSE_SETXATTR_EXT)
1178                                 fc->setxattr_ext = 1;
1179                 } else {
1180                         ra_pages = fc->max_read / PAGE_SIZE;
1181                         fc->no_lock = 1;
1182                         fc->no_flock = 1;
1183                 }
1184
1185                 fm->sb->s_bdi->ra_pages =
1186                                 min(fm->sb->s_bdi->ra_pages, ra_pages);
1187                 fc->minor = arg->minor;
1188                 fc->max_write = arg->minor < 5 ? 4096 : arg->max_write;
1189                 fc->max_write = max_t(unsigned, 4096, fc->max_write);
1190                 fc->conn_init = 1;
1191         }
1192         kfree(ia);
1193
1194         if (!ok) {
1195                 fc->conn_init = 0;
1196                 fc->conn_error = 1;
1197         }
1198
1199         fuse_set_initialized(fc);
1200         wake_up_all(&fc->blocked_waitq);
1201 }
1202
1203 void fuse_send_init(struct fuse_mount *fm)
1204 {
1205         struct fuse_init_args *ia;
1206
1207         ia = kzalloc(sizeof(*ia), GFP_KERNEL | __GFP_NOFAIL);
1208
1209         ia->in.major = FUSE_KERNEL_VERSION;
1210         ia->in.minor = FUSE_KERNEL_MINOR_VERSION;
1211         ia->in.max_readahead = fm->sb->s_bdi->ra_pages * PAGE_SIZE;
1212         ia->in.flags |=
1213                 FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC |
1214                 FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK |
1215                 FUSE_SPLICE_WRITE | FUSE_SPLICE_MOVE | FUSE_SPLICE_READ |
1216                 FUSE_FLOCK_LOCKS | FUSE_HAS_IOCTL_DIR | FUSE_AUTO_INVAL_DATA |
1217                 FUSE_DO_READDIRPLUS | FUSE_READDIRPLUS_AUTO | FUSE_ASYNC_DIO |
1218                 FUSE_WRITEBACK_CACHE | FUSE_NO_OPEN_SUPPORT |
1219                 FUSE_PARALLEL_DIROPS | FUSE_HANDLE_KILLPRIV | FUSE_POSIX_ACL |
1220                 FUSE_ABORT_ERROR | FUSE_MAX_PAGES | FUSE_CACHE_SYMLINKS |
1221                 FUSE_NO_OPENDIR_SUPPORT | FUSE_EXPLICIT_INVAL_DATA |
1222                 FUSE_HANDLE_KILLPRIV_V2 | FUSE_SETXATTR_EXT;
1223 #ifdef CONFIG_FUSE_DAX
1224         if (fm->fc->dax)
1225                 ia->in.flags |= FUSE_MAP_ALIGNMENT;
1226 #endif
1227         if (fm->fc->auto_submounts)
1228                 ia->in.flags |= FUSE_SUBMOUNTS;
1229
1230         ia->args.opcode = FUSE_INIT;
1231         ia->args.in_numargs = 1;
1232         ia->args.in_args[0].size = sizeof(ia->in);
1233         ia->args.in_args[0].value = &ia->in;
1234         ia->args.out_numargs = 1;
1235         /* Variable length argument used for backward compatibility
1236            with interface version < 7.5.  Rest of init_out is zeroed
1237            by do_get_request(), so a short reply is not a problem */
1238         ia->args.out_argvar = true;
1239         ia->args.out_args[0].size = sizeof(ia->out);
1240         ia->args.out_args[0].value = &ia->out;
1241         ia->args.force = true;
1242         ia->args.nocreds = true;
1243         ia->args.end = process_init_reply;
1244
1245         if (fuse_simple_background(fm, &ia->args, GFP_KERNEL) != 0)
1246                 process_init_reply(fm, &ia->args, -ENOTCONN);
1247 }
1248 EXPORT_SYMBOL_GPL(fuse_send_init);
1249
1250 void fuse_free_conn(struct fuse_conn *fc)
1251 {
1252         WARN_ON(!list_empty(&fc->devices));
1253         kfree_rcu(fc, rcu);
1254 }
1255 EXPORT_SYMBOL_GPL(fuse_free_conn);
1256
1257 static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
1258 {
1259         int err;
1260         char *suffix = "";
1261
1262         if (sb->s_bdev) {
1263                 suffix = "-fuseblk";
1264                 /*
1265                  * sb->s_bdi points to blkdev's bdi however we want to redirect
1266                  * it to our private bdi...
1267                  */
1268                 bdi_put(sb->s_bdi);
1269                 sb->s_bdi = &noop_backing_dev_info;
1270         }
1271         err = super_setup_bdi_name(sb, "%u:%u%s", MAJOR(fc->dev),
1272                                    MINOR(fc->dev), suffix);
1273         if (err)
1274                 return err;
1275
1276         /* fuse does it's own writeback accounting */
1277         sb->s_bdi->capabilities &= ~BDI_CAP_WRITEBACK_ACCT;
1278         sb->s_bdi->capabilities |= BDI_CAP_STRICTLIMIT;
1279
1280         /*
1281          * For a single fuse filesystem use max 1% of dirty +
1282          * writeback threshold.
1283          *
1284          * This gives about 1M of write buffer for memory maps on a
1285          * machine with 1G and 10% dirty_ratio, which should be more
1286          * than enough.
1287          *
1288          * Privileged users can raise it by writing to
1289          *
1290          *    /sys/class/bdi/<bdi>/max_ratio
1291          */
1292         bdi_set_max_ratio(sb->s_bdi, 1);
1293
1294         return 0;
1295 }
1296
1297 struct fuse_dev *fuse_dev_alloc(void)
1298 {
1299         struct fuse_dev *fud;
1300         struct list_head *pq;
1301
1302         fud = kzalloc(sizeof(struct fuse_dev), GFP_KERNEL);
1303         if (!fud)
1304                 return NULL;
1305
1306         pq = kcalloc(FUSE_PQ_HASH_SIZE, sizeof(struct list_head), GFP_KERNEL);
1307         if (!pq) {
1308                 kfree(fud);
1309                 return NULL;
1310         }
1311
1312         fud->pq.processing = pq;
1313         fuse_pqueue_init(&fud->pq);
1314
1315         return fud;
1316 }
1317 EXPORT_SYMBOL_GPL(fuse_dev_alloc);
1318
1319 void fuse_dev_install(struct fuse_dev *fud, struct fuse_conn *fc)
1320 {
1321         fud->fc = fuse_conn_get(fc);
1322         spin_lock(&fc->lock);
1323         list_add_tail(&fud->entry, &fc->devices);
1324         spin_unlock(&fc->lock);
1325 }
1326 EXPORT_SYMBOL_GPL(fuse_dev_install);
1327
1328 struct fuse_dev *fuse_dev_alloc_install(struct fuse_conn *fc)
1329 {
1330         struct fuse_dev *fud;
1331
1332         fud = fuse_dev_alloc();
1333         if (!fud)
1334                 return NULL;
1335
1336         fuse_dev_install(fud, fc);
1337         return fud;
1338 }
1339 EXPORT_SYMBOL_GPL(fuse_dev_alloc_install);
1340
1341 void fuse_dev_free(struct fuse_dev *fud)
1342 {
1343         struct fuse_conn *fc = fud->fc;
1344
1345         if (fc) {
1346                 spin_lock(&fc->lock);
1347                 list_del(&fud->entry);
1348                 spin_unlock(&fc->lock);
1349
1350                 fuse_conn_put(fc);
1351         }
1352         kfree(fud->pq.processing);
1353         kfree(fud);
1354 }
1355 EXPORT_SYMBOL_GPL(fuse_dev_free);
1356
1357 static void fuse_fill_attr_from_inode(struct fuse_attr *attr,
1358                                       const struct fuse_inode *fi)
1359 {
1360         *attr = (struct fuse_attr){
1361                 .ino            = fi->inode.i_ino,
1362                 .size           = fi->inode.i_size,
1363                 .blocks         = fi->inode.i_blocks,
1364                 .atime          = fi->inode.i_atime.tv_sec,
1365                 .mtime          = fi->inode.i_mtime.tv_sec,
1366                 .ctime          = fi->inode.i_ctime.tv_sec,
1367                 .atimensec      = fi->inode.i_atime.tv_nsec,
1368                 .mtimensec      = fi->inode.i_mtime.tv_nsec,
1369                 .ctimensec      = fi->inode.i_ctime.tv_nsec,
1370                 .mode           = fi->inode.i_mode,
1371                 .nlink          = fi->inode.i_nlink,
1372                 .uid            = fi->inode.i_uid.val,
1373                 .gid            = fi->inode.i_gid.val,
1374                 .rdev           = fi->inode.i_rdev,
1375                 .blksize        = 1u << fi->inode.i_blkbits,
1376         };
1377 }
1378
1379 static void fuse_sb_defaults(struct super_block *sb)
1380 {
1381         sb->s_magic = FUSE_SUPER_MAGIC;
1382         sb->s_op = &fuse_super_operations;
1383         sb->s_xattr = fuse_xattr_handlers;
1384         sb->s_maxbytes = MAX_LFS_FILESIZE;
1385         sb->s_time_gran = 1;
1386         sb->s_export_op = &fuse_export_operations;
1387         sb->s_iflags |= SB_I_IMA_UNVERIFIABLE_SIGNATURE;
1388         if (sb->s_user_ns != &init_user_ns)
1389                 sb->s_iflags |= SB_I_UNTRUSTED_MOUNTER;
1390         sb->s_flags &= ~(SB_NOSEC | SB_I_VERSION);
1391
1392         /*
1393          * If we are not in the initial user namespace posix
1394          * acls must be translated.
1395          */
1396         if (sb->s_user_ns != &init_user_ns)
1397                 sb->s_xattr = fuse_no_acl_xattr_handlers;
1398 }
1399
1400 static int fuse_fill_super_submount(struct super_block *sb,
1401                                     struct fuse_inode *parent_fi)
1402 {
1403         struct fuse_mount *fm = get_fuse_mount_super(sb);
1404         struct super_block *parent_sb = parent_fi->inode.i_sb;
1405         struct fuse_attr root_attr;
1406         struct inode *root;
1407
1408         fuse_sb_defaults(sb);
1409         fm->sb = sb;
1410
1411         WARN_ON(sb->s_bdi != &noop_backing_dev_info);
1412         sb->s_bdi = bdi_get(parent_sb->s_bdi);
1413
1414         sb->s_xattr = parent_sb->s_xattr;
1415         sb->s_time_gran = parent_sb->s_time_gran;
1416         sb->s_blocksize = parent_sb->s_blocksize;
1417         sb->s_blocksize_bits = parent_sb->s_blocksize_bits;
1418         sb->s_subtype = kstrdup(parent_sb->s_subtype, GFP_KERNEL);
1419         if (parent_sb->s_subtype && !sb->s_subtype)
1420                 return -ENOMEM;
1421
1422         fuse_fill_attr_from_inode(&root_attr, parent_fi);
1423         root = fuse_iget(sb, parent_fi->nodeid, 0, &root_attr, 0, 0);
1424         /*
1425          * This inode is just a duplicate, so it is not looked up and
1426          * its nlookup should not be incremented.  fuse_iget() does
1427          * that, though, so undo it here.
1428          */
1429         get_fuse_inode(root)->nlookup--;
1430         sb->s_d_op = &fuse_dentry_operations;
1431         sb->s_root = d_make_root(root);
1432         if (!sb->s_root)
1433                 return -ENOMEM;
1434
1435         return 0;
1436 }
1437
1438 /* Filesystem context private data holds the FUSE inode of the mount point */
1439 static int fuse_get_tree_submount(struct fs_context *fsc)
1440 {
1441         struct fuse_mount *fm;
1442         struct fuse_inode *mp_fi = fsc->fs_private;
1443         struct fuse_conn *fc = get_fuse_conn(&mp_fi->inode);
1444         struct super_block *sb;
1445         int err;
1446
1447         fm = kzalloc(sizeof(struct fuse_mount), GFP_KERNEL);
1448         if (!fm)
1449                 return -ENOMEM;
1450
1451         fm->fc = fuse_conn_get(fc);
1452         fsc->s_fs_info = fm;
1453         sb = sget_fc(fsc, NULL, set_anon_super_fc);
1454         if (fsc->s_fs_info)
1455                 fuse_mount_destroy(fm);
1456         if (IS_ERR(sb))
1457                 return PTR_ERR(sb);
1458
1459         /* Initialize superblock, making @mp_fi its root */
1460         err = fuse_fill_super_submount(sb, mp_fi);
1461         if (err) {
1462                 deactivate_locked_super(sb);
1463                 return err;
1464         }
1465
1466         down_write(&fc->killsb);
1467         list_add_tail(&fm->fc_entry, &fc->mounts);
1468         up_write(&fc->killsb);
1469
1470         sb->s_flags |= SB_ACTIVE;
1471         fsc->root = dget(sb->s_root);
1472
1473         return 0;
1474 }
1475
1476 static const struct fs_context_operations fuse_context_submount_ops = {
1477         .get_tree       = fuse_get_tree_submount,
1478 };
1479
1480 int fuse_init_fs_context_submount(struct fs_context *fsc)
1481 {
1482         fsc->ops = &fuse_context_submount_ops;
1483         return 0;
1484 }
1485 EXPORT_SYMBOL_GPL(fuse_init_fs_context_submount);
1486
1487 int fuse_fill_super_common(struct super_block *sb, struct fuse_fs_context *ctx)
1488 {
1489         struct fuse_dev *fud = NULL;
1490         struct fuse_mount *fm = get_fuse_mount_super(sb);
1491         struct fuse_conn *fc = fm->fc;
1492         struct inode *root;
1493         struct dentry *root_dentry;
1494         int err;
1495
1496         err = -EINVAL;
1497         if (sb->s_flags & SB_MANDLOCK)
1498                 goto err;
1499
1500         rcu_assign_pointer(fc->curr_bucket, fuse_sync_bucket_alloc());
1501         fuse_sb_defaults(sb);
1502
1503         if (ctx->is_bdev) {
1504 #ifdef CONFIG_BLOCK
1505                 err = -EINVAL;
1506                 if (!sb_set_blocksize(sb, ctx->blksize))
1507                         goto err;
1508 #endif
1509         } else {
1510                 sb->s_blocksize = PAGE_SIZE;
1511                 sb->s_blocksize_bits = PAGE_SHIFT;
1512         }
1513
1514         sb->s_subtype = ctx->subtype;
1515         ctx->subtype = NULL;
1516         if (IS_ENABLED(CONFIG_FUSE_DAX)) {
1517                 err = fuse_dax_conn_alloc(fc, ctx->dax_dev);
1518                 if (err)
1519                         goto err;
1520         }
1521
1522         if (ctx->fudptr) {
1523                 err = -ENOMEM;
1524                 fud = fuse_dev_alloc_install(fc);
1525                 if (!fud)
1526                         goto err_free_dax;
1527         }
1528
1529         fc->dev = sb->s_dev;
1530         fm->sb = sb;
1531         err = fuse_bdi_init(fc, sb);
1532         if (err)
1533                 goto err_dev_free;
1534
1535         /* Handle umasking inside the fuse code */
1536         if (sb->s_flags & SB_POSIXACL)
1537                 fc->dont_mask = 1;
1538         sb->s_flags |= SB_POSIXACL;
1539
1540         fc->default_permissions = ctx->default_permissions;
1541         fc->allow_other = ctx->allow_other;
1542         fc->user_id = ctx->user_id;
1543         fc->group_id = ctx->group_id;
1544         fc->legacy_opts_show = ctx->legacy_opts_show;
1545         fc->max_read = max_t(unsigned int, 4096, ctx->max_read);
1546         fc->destroy = ctx->destroy;
1547         fc->no_control = ctx->no_control;
1548         fc->no_force_umount = ctx->no_force_umount;
1549
1550         err = -ENOMEM;
1551         root = fuse_get_root_inode(sb, ctx->rootmode);
1552         sb->s_d_op = &fuse_root_dentry_operations;
1553         root_dentry = d_make_root(root);
1554         if (!root_dentry)
1555                 goto err_dev_free;
1556         /* Root dentry doesn't have .d_revalidate */
1557         sb->s_d_op = &fuse_dentry_operations;
1558
1559         mutex_lock(&fuse_mutex);
1560         err = -EINVAL;
1561         if (ctx->fudptr && *ctx->fudptr)
1562                 goto err_unlock;
1563
1564         err = fuse_ctl_add_conn(fc);
1565         if (err)
1566                 goto err_unlock;
1567
1568         list_add_tail(&fc->entry, &fuse_conn_list);
1569         sb->s_root = root_dentry;
1570         if (ctx->fudptr)
1571                 *ctx->fudptr = fud;
1572         mutex_unlock(&fuse_mutex);
1573         return 0;
1574
1575  err_unlock:
1576         mutex_unlock(&fuse_mutex);
1577         dput(root_dentry);
1578  err_dev_free:
1579         if (fud)
1580                 fuse_dev_free(fud);
1581  err_free_dax:
1582         if (IS_ENABLED(CONFIG_FUSE_DAX))
1583                 fuse_dax_conn_free(fc);
1584  err:
1585         return err;
1586 }
1587 EXPORT_SYMBOL_GPL(fuse_fill_super_common);
1588
1589 static int fuse_fill_super(struct super_block *sb, struct fs_context *fsc)
1590 {
1591         struct fuse_fs_context *ctx = fsc->fs_private;
1592         int err;
1593
1594         if (!ctx->file || !ctx->rootmode_present ||
1595             !ctx->user_id_present || !ctx->group_id_present)
1596                 return -EINVAL;
1597
1598         /*
1599          * Require mount to happen from the same user namespace which
1600          * opened /dev/fuse to prevent potential attacks.
1601          */
1602         if ((ctx->file->f_op != &fuse_dev_operations) ||
1603             (ctx->file->f_cred->user_ns != sb->s_user_ns))
1604                 return -EINVAL;
1605         ctx->fudptr = &ctx->file->private_data;
1606
1607         err = fuse_fill_super_common(sb, ctx);
1608         if (err)
1609                 return err;
1610         /* file->private_data shall be visible on all CPUs after this */
1611         smp_mb();
1612         fuse_send_init(get_fuse_mount_super(sb));
1613         return 0;
1614 }
1615
1616 /*
1617  * This is the path where user supplied an already initialized fuse dev.  In
1618  * this case never create a new super if the old one is gone.
1619  */
1620 static int fuse_set_no_super(struct super_block *sb, struct fs_context *fsc)
1621 {
1622         return -ENOTCONN;
1623 }
1624
1625 static int fuse_test_super(struct super_block *sb, struct fs_context *fsc)
1626 {
1627
1628         return fsc->sget_key == get_fuse_conn_super(sb);
1629 }
1630
1631 static int fuse_get_tree(struct fs_context *fsc)
1632 {
1633         struct fuse_fs_context *ctx = fsc->fs_private;
1634         struct fuse_dev *fud;
1635         struct fuse_conn *fc;
1636         struct fuse_mount *fm;
1637         struct super_block *sb;
1638         int err;
1639
1640         fc = kmalloc(sizeof(*fc), GFP_KERNEL);
1641         if (!fc)
1642                 return -ENOMEM;
1643
1644         fm = kzalloc(sizeof(*fm), GFP_KERNEL);
1645         if (!fm) {
1646                 kfree(fc);
1647                 return -ENOMEM;
1648         }
1649
1650         fuse_conn_init(fc, fm, fsc->user_ns, &fuse_dev_fiq_ops, NULL);
1651         fc->release = fuse_free_conn;
1652
1653         fsc->s_fs_info = fm;
1654
1655         if (ctx->fd_present)
1656                 ctx->file = fget(ctx->fd);
1657
1658         if (IS_ENABLED(CONFIG_BLOCK) && ctx->is_bdev) {
1659                 err = get_tree_bdev(fsc, fuse_fill_super);
1660                 goto out;
1661         }
1662         /*
1663          * While block dev mount can be initialized with a dummy device fd
1664          * (found by device name), normal fuse mounts can't
1665          */
1666         err = -EINVAL;
1667         if (!ctx->file)
1668                 goto out;
1669
1670         /*
1671          * Allow creating a fuse mount with an already initialized fuse
1672          * connection
1673          */
1674         fud = READ_ONCE(ctx->file->private_data);
1675         if (ctx->file->f_op == &fuse_dev_operations && fud) {
1676                 fsc->sget_key = fud->fc;
1677                 sb = sget_fc(fsc, fuse_test_super, fuse_set_no_super);
1678                 err = PTR_ERR_OR_ZERO(sb);
1679                 if (!IS_ERR(sb))
1680                         fsc->root = dget(sb->s_root);
1681         } else {
1682                 err = get_tree_nodev(fsc, fuse_fill_super);
1683         }
1684 out:
1685         if (fsc->s_fs_info)
1686                 fuse_mount_destroy(fm);
1687         if (ctx->file)
1688                 fput(ctx->file);
1689         return err;
1690 }
1691
1692 static const struct fs_context_operations fuse_context_ops = {
1693         .free           = fuse_free_fsc,
1694         .parse_param    = fuse_parse_param,
1695         .reconfigure    = fuse_reconfigure,
1696         .get_tree       = fuse_get_tree,
1697 };
1698
1699 /*
1700  * Set up the filesystem mount context.
1701  */
1702 static int fuse_init_fs_context(struct fs_context *fsc)
1703 {
1704         struct fuse_fs_context *ctx;
1705
1706         ctx = kzalloc(sizeof(struct fuse_fs_context), GFP_KERNEL);
1707         if (!ctx)
1708                 return -ENOMEM;
1709
1710         ctx->max_read = ~0;
1711         ctx->blksize = FUSE_DEFAULT_BLKSIZE;
1712         ctx->legacy_opts_show = true;
1713
1714 #ifdef CONFIG_BLOCK
1715         if (fsc->fs_type == &fuseblk_fs_type) {
1716                 ctx->is_bdev = true;
1717                 ctx->destroy = true;
1718         }
1719 #endif
1720
1721         fsc->fs_private = ctx;
1722         fsc->ops = &fuse_context_ops;
1723         return 0;
1724 }
1725
1726 bool fuse_mount_remove(struct fuse_mount *fm)
1727 {
1728         struct fuse_conn *fc = fm->fc;
1729         bool last = false;
1730
1731         down_write(&fc->killsb);
1732         list_del_init(&fm->fc_entry);
1733         if (list_empty(&fc->mounts))
1734                 last = true;
1735         up_write(&fc->killsb);
1736
1737         return last;
1738 }
1739 EXPORT_SYMBOL_GPL(fuse_mount_remove);
1740
1741 void fuse_conn_destroy(struct fuse_mount *fm)
1742 {
1743         struct fuse_conn *fc = fm->fc;
1744
1745         if (fc->destroy)
1746                 fuse_send_destroy(fm);
1747
1748         fuse_abort_conn(fc);
1749         fuse_wait_aborted(fc);
1750
1751         if (!list_empty(&fc->entry)) {
1752                 mutex_lock(&fuse_mutex);
1753                 list_del(&fc->entry);
1754                 fuse_ctl_remove_conn(fc);
1755                 mutex_unlock(&fuse_mutex);
1756         }
1757 }
1758 EXPORT_SYMBOL_GPL(fuse_conn_destroy);
1759
1760 static void fuse_sb_destroy(struct super_block *sb)
1761 {
1762         struct fuse_mount *fm = get_fuse_mount_super(sb);
1763         bool last;
1764
1765         if (sb->s_root) {
1766                 last = fuse_mount_remove(fm);
1767                 if (last)
1768                         fuse_conn_destroy(fm);
1769         }
1770 }
1771
1772 void fuse_mount_destroy(struct fuse_mount *fm)
1773 {
1774         fuse_conn_put(fm->fc);
1775         kfree(fm);
1776 }
1777 EXPORT_SYMBOL(fuse_mount_destroy);
1778
1779 static void fuse_kill_sb_anon(struct super_block *sb)
1780 {
1781         fuse_sb_destroy(sb);
1782         kill_anon_super(sb);
1783         fuse_mount_destroy(get_fuse_mount_super(sb));
1784 }
1785
1786 static struct file_system_type fuse_fs_type = {
1787         .owner          = THIS_MODULE,
1788         .name           = "fuse",
1789         .fs_flags       = FS_HAS_SUBTYPE | FS_USERNS_MOUNT,
1790         .init_fs_context = fuse_init_fs_context,
1791         .parameters     = fuse_fs_parameters,
1792         .kill_sb        = fuse_kill_sb_anon,
1793 };
1794 MODULE_ALIAS_FS("fuse");
1795
1796 #ifdef CONFIG_BLOCK
1797 static void fuse_kill_sb_blk(struct super_block *sb)
1798 {
1799         fuse_sb_destroy(sb);
1800         kill_block_super(sb);
1801         fuse_mount_destroy(get_fuse_mount_super(sb));
1802 }
1803
1804 static struct file_system_type fuseblk_fs_type = {
1805         .owner          = THIS_MODULE,
1806         .name           = "fuseblk",
1807         .init_fs_context = fuse_init_fs_context,
1808         .parameters     = fuse_fs_parameters,
1809         .kill_sb        = fuse_kill_sb_blk,
1810         .fs_flags       = FS_REQUIRES_DEV | FS_HAS_SUBTYPE,
1811 };
1812 MODULE_ALIAS_FS("fuseblk");
1813
1814 static inline int register_fuseblk(void)
1815 {
1816         return register_filesystem(&fuseblk_fs_type);
1817 }
1818
1819 static inline void unregister_fuseblk(void)
1820 {
1821         unregister_filesystem(&fuseblk_fs_type);
1822 }
1823 #else
1824 static inline int register_fuseblk(void)
1825 {
1826         return 0;
1827 }
1828
1829 static inline void unregister_fuseblk(void)
1830 {
1831 }
1832 #endif
1833
1834 static void fuse_inode_init_once(void *foo)
1835 {
1836         struct inode *inode = foo;
1837
1838         inode_init_once(inode);
1839 }
1840
1841 static int __init fuse_fs_init(void)
1842 {
1843         int err;
1844
1845         fuse_inode_cachep = kmem_cache_create("fuse_inode",
1846                         sizeof(struct fuse_inode), 0,
1847                         SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT|SLAB_RECLAIM_ACCOUNT,
1848                         fuse_inode_init_once);
1849         err = -ENOMEM;
1850         if (!fuse_inode_cachep)
1851                 goto out;
1852
1853         err = register_fuseblk();
1854         if (err)
1855                 goto out2;
1856
1857         err = register_filesystem(&fuse_fs_type);
1858         if (err)
1859                 goto out3;
1860
1861         return 0;
1862
1863  out3:
1864         unregister_fuseblk();
1865  out2:
1866         kmem_cache_destroy(fuse_inode_cachep);
1867  out:
1868         return err;
1869 }
1870
1871 static void fuse_fs_cleanup(void)
1872 {
1873         unregister_filesystem(&fuse_fs_type);
1874         unregister_fuseblk();
1875
1876         /*
1877          * Make sure all delayed rcu free inodes are flushed before we
1878          * destroy cache.
1879          */
1880         rcu_barrier();
1881         kmem_cache_destroy(fuse_inode_cachep);
1882 }
1883
1884 static struct kobject *fuse_kobj;
1885
1886 static int fuse_sysfs_init(void)
1887 {
1888         int err;
1889
1890         fuse_kobj = kobject_create_and_add("fuse", fs_kobj);
1891         if (!fuse_kobj) {
1892                 err = -ENOMEM;
1893                 goto out_err;
1894         }
1895
1896         err = sysfs_create_mount_point(fuse_kobj, "connections");
1897         if (err)
1898                 goto out_fuse_unregister;
1899
1900         return 0;
1901
1902  out_fuse_unregister:
1903         kobject_put(fuse_kobj);
1904  out_err:
1905         return err;
1906 }
1907
1908 static void fuse_sysfs_cleanup(void)
1909 {
1910         sysfs_remove_mount_point(fuse_kobj, "connections");
1911         kobject_put(fuse_kobj);
1912 }
1913
1914 static int __init fuse_init(void)
1915 {
1916         int res;
1917
1918         pr_info("init (API version %i.%i)\n",
1919                 FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);
1920
1921         INIT_LIST_HEAD(&fuse_conn_list);
1922         res = fuse_fs_init();
1923         if (res)
1924                 goto err;
1925
1926         res = fuse_dev_init();
1927         if (res)
1928                 goto err_fs_cleanup;
1929
1930         res = fuse_sysfs_init();
1931         if (res)
1932                 goto err_dev_cleanup;
1933
1934         res = fuse_ctl_init();
1935         if (res)
1936                 goto err_sysfs_cleanup;
1937
1938         sanitize_global_limit(&max_user_bgreq);
1939         sanitize_global_limit(&max_user_congthresh);
1940
1941         return 0;
1942
1943  err_sysfs_cleanup:
1944         fuse_sysfs_cleanup();
1945  err_dev_cleanup:
1946         fuse_dev_cleanup();
1947  err_fs_cleanup:
1948         fuse_fs_cleanup();
1949  err:
1950         return res;
1951 }
1952
1953 static void __exit fuse_exit(void)
1954 {
1955         pr_debug("exit\n");
1956
1957         fuse_ctl_cleanup();
1958         fuse_sysfs_cleanup();
1959         fuse_fs_cleanup();
1960         fuse_dev_cleanup();
1961 }
1962
1963 module_init(fuse_init);
1964 module_exit(fuse_exit);