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/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 #include <uapi/linux/magic.h>
  27
  28 MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
  29 MODULE_DESCRIPTION("Filesystem in Userspace");
  30 MODULE_LICENSE("GPL");
  31
  32 static struct kmem_cache *fuse_inode_cachep;
  33 struct list_head fuse_conn_list;
  34 DEFINE_MUTEX(fuse_mutex);
  35
  36 static int set_global_limit(const char *val, const struct kernel_param *kp);
  37
  38 unsigned max_user_bgreq;
  39 module_param_call(max_user_bgreq, set_global_limit, param_get_uint,
  40                   &max_user_bgreq, 0644);
  41 __MODULE_PARM_TYPE(max_user_bgreq, "uint");
  42 MODULE_PARM_DESC(max_user_bgreq,
  43  "Global limit for the maximum number of backgrounded requests an "
  44  "unprivileged user can set");
  45
  46 unsigned max_user_congthresh;
  47 module_param_call(max_user_congthresh, set_global_limit, param_get_uint,
  48                   &max_user_congthresh, 0644);
  49 __MODULE_PARM_TYPE(max_user_congthresh, "uint");
  50 MODULE_PARM_DESC(max_user_congthresh,
  51  "Global limit for the maximum congestion threshold an "
  52  "unprivileged user can set");
  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 #ifdef CONFIG_BLOCK
  63 static struct file_system_type fuseblk_fs_type;
  64 #endif
  65
  66 struct fuse_forget_link *fuse_alloc_forget(void)
  67 {
  68         return kzalloc(sizeof(struct fuse_forget_link), GFP_KERNEL_ACCOUNT);
  69 }
  70
  71 static struct inode *fuse_alloc_inode(struct super_block *sb)
  72 {
  73         struct fuse_inode *fi;
  74
  75         fi = alloc_inode_sb(sb, fuse_inode_cachep, GFP_KERNEL);
  76         if (!fi)
  77                 return NULL;
  78
  79         fi->i_time = 0;
  80         fi->inval_mask = 0;
  81         fi->nodeid = 0;
  82         fi->nlookup = 0;
  83         fi->attr_version = 0;
  84         fi->orig_ino = 0;
  85         fi->state = 0;
  86         mutex_init(&fi->mutex);
  87         spin_lock_init(&fi->lock);
  88         fi->forget = fuse_alloc_forget();
  89         if (!fi->forget)
  90                 goto out_free;
  91
  92         if (IS_ENABLED(CONFIG_FUSE_DAX) && !fuse_dax_inode_alloc(sb, fi))
  93                 goto out_free_forget;
  94
  95         return &fi->inode;
  96
  97 out_free_forget:
  98         kfree(fi->forget);
  99 out_free:
 100         kmem_cache_free(fuse_inode_cachep, fi);
 101         return NULL;
 102 }
 103
 104 static void fuse_free_inode(struct inode *inode)
 105 {
 106         struct fuse_inode *fi = get_fuse_inode(inode);
 107
 108         mutex_destroy(&fi->mutex);
 109         kfree(fi->forget);
 110 #ifdef CONFIG_FUSE_DAX
 111         kfree(fi->dax);
 112 #endif
 113         kmem_cache_free(fuse_inode_cachep, fi);
 114 }
 115
 116 static void fuse_evict_inode(struct inode *inode)
 117 {
 118         struct fuse_inode *fi = get_fuse_inode(inode);
 119
 120         /* Will write inode on close/munmap and in all other dirtiers */
 121         WARN_ON(inode->i_state & I_DIRTY_INODE);
 122
 123         truncate_inode_pages_final(&inode->i_data);
 124         clear_inode(inode);
 125         if (inode->i_sb->s_flags & SB_ACTIVE) {
 126                 struct fuse_conn *fc = get_fuse_conn(inode);
 127
 128                 if (FUSE_IS_DAX(inode))
 129                         fuse_dax_inode_cleanup(inode);
 130                 if (fi->nlookup) {
 131                         fuse_queue_forget(fc, fi->forget, fi->nodeid,
 132                                           fi->nlookup);
 133                         fi->forget = NULL;
 134                 }
 135         }
 136         if (S_ISREG(inode->i_mode) && !fuse_is_bad(inode)) {
 137                 WARN_ON(!list_empty(&fi->write_files));
 138                 WARN_ON(!list_empty(&fi->queued_writes));
 139         }
 140 }
 141
 142 static int fuse_reconfigure(struct fs_context *fsc)
 143 {
 144         struct super_block *sb = fsc->root->d_sb;
 145
 146         sync_filesystem(sb);
 147         if (fsc->sb_flags & SB_MANDLOCK)
 148                 return -EINVAL;
 149
 150         return 0;
 151 }
 152
 153 /*
 154  * ino_t is 32-bits on 32-bit arch. We have to squash the 64-bit value down
 155  * so that it will fit.
 156  */
 157 static ino_t fuse_squash_ino(u64 ino64)
 158 {
 159         ino_t ino = (ino_t) ino64;
 160         if (sizeof(ino_t) < sizeof(u64))
 161                 ino ^= ino64 >> (sizeof(u64) - sizeof(ino_t)) * 8;
 162         return ino;
 163 }
 164
 165 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
 166                                    u64 attr_valid, u32 cache_mask)
 167 {
 168         struct fuse_conn *fc = get_fuse_conn(inode);
 169         struct fuse_inode *fi = get_fuse_inode(inode);
 170
 171         lockdep_assert_held(&fi->lock);
 172
 173         fi->attr_version = atomic64_inc_return(&fc->attr_version);
 174         fi->i_time = attr_valid;
 175         WRITE_ONCE(fi->inval_mask, 0);
 176
 177         inode->i_ino     = fuse_squash_ino(attr->ino);
 178         inode->i_mode    = (inode->i_mode & S_IFMT) | (attr->mode & 07777);
 179         set_nlink(inode, attr->nlink);
 180         inode->i_uid     = make_kuid(fc->user_ns, attr->uid);
 181         inode->i_gid     = make_kgid(fc->user_ns, attr->gid);
 182         inode->i_blocks  = attr->blocks;
 183
 184         /* Sanitize nsecs */
 185         attr->atimensec = min_t(u32, attr->atimensec, NSEC_PER_SEC - 1);
 186         attr->mtimensec = min_t(u32, attr->mtimensec, NSEC_PER_SEC - 1);
 187         attr->ctimensec = min_t(u32, attr->ctimensec, NSEC_PER_SEC - 1);
 188
 189         inode->i_atime.tv_sec   = attr->atime;
 190         inode->i_atime.tv_nsec  = attr->atimensec;
 191         /* mtime from server may be stale due to local buffered write */
 192         if (!(cache_mask & STATX_MTIME)) {
 193                 inode->i_mtime.tv_sec   = attr->mtime;
 194                 inode->i_mtime.tv_nsec  = attr->mtimensec;
 195         }
 196         if (!(cache_mask & STATX_CTIME)) {
 197                 inode->i_ctime.tv_sec   = attr->ctime;
 198                 inode->i_ctime.tv_nsec  = attr->ctimensec;
 199         }
 200
 201         if (attr->blksize != 0)
 202                 inode->i_blkbits = ilog2(attr->blksize);
 203         else
 204                 inode->i_blkbits = inode->i_sb->s_blocksize_bits;
 205
 206         /*
 207          * Don't set the sticky bit in i_mode, unless we want the VFS
 208          * to check permissions.  This prevents failures due to the
 209          * check in may_delete().
 210          */
 211         fi->orig_i_mode = inode->i_mode;
 212         if (!fc->default_permissions)
 213                 inode->i_mode &= ~S_ISVTX;
 214
 215         fi->orig_ino = attr->ino;
 216
 217         /*
 218          * We are refreshing inode data and it is possible that another
 219          * client set suid/sgid or security.capability xattr. So clear
 220          * S_NOSEC. Ideally, we could have cleared it only if suid/sgid
 221          * was set or if security.capability xattr was set. But we don't
 222          * know if security.capability has been set or not. So clear it
 223          * anyway. Its less efficient but should be safe.
 224          */
 225         inode->i_flags &= ~S_NOSEC;
 226 }
 227
 228 u32 fuse_get_cache_mask(struct inode *inode)
 229 {
 230         struct fuse_conn *fc = get_fuse_conn(inode);
 231
 232         if (!fc->writeback_cache || !S_ISREG(inode->i_mode))
 233                 return 0;
 234
 235         return STATX_MTIME | STATX_CTIME | STATX_SIZE;
 236 }
 237
 238 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
 239                             u64 attr_valid, u64 attr_version)
 240 {
 241         struct fuse_conn *fc = get_fuse_conn(inode);
 242         struct fuse_inode *fi = get_fuse_inode(inode);
 243         u32 cache_mask;
 244         loff_t oldsize;
 245         struct timespec64 old_mtime;
 246
 247         spin_lock(&fi->lock);
 248         /*
 249          * In case of writeback_cache enabled, writes update mtime, ctime and
 250          * may update i_size.  In these cases trust the cached value in the
 251          * inode.
 252          */
 253         cache_mask = fuse_get_cache_mask(inode);
 254         if (cache_mask & STATX_SIZE)
 255                 attr->size = i_size_read(inode);
 256
 257         if (cache_mask & STATX_MTIME) {
 258                 attr->mtime = inode->i_mtime.tv_sec;
 259                 attr->mtimensec = inode->i_mtime.tv_nsec;
 260         }
 261         if (cache_mask & STATX_CTIME) {
 262                 attr->ctime = inode->i_ctime.tv_sec;
 263                 attr->ctimensec = inode->i_ctime.tv_nsec;
 264         }
 265
 266         if ((attr_version != 0 && fi->attr_version > attr_version) ||
 267             test_bit(FUSE_I_SIZE_UNSTABLE, &fi->state)) {
 268                 spin_unlock(&fi->lock);
 269                 return;
 270         }
 271
 272         old_mtime = inode->i_mtime;
 273         fuse_change_attributes_common(inode, attr, attr_valid, cache_mask);
 274
 275         oldsize = inode->i_size;
 276         /*
 277          * In case of writeback_cache enabled, the cached writes beyond EOF
 278          * extend local i_size without keeping userspace server in sync. So,
 279          * attr->size coming from server can be stale. We cannot trust it.
 280          */
 281         if (!(cache_mask & STATX_SIZE))
 282                 i_size_write(inode, attr->size);
 283         spin_unlock(&fi->lock);
 284
 285         if (!cache_mask && S_ISREG(inode->i_mode)) {
 286                 bool inval = false;
 287
 288                 if (oldsize != attr->size) {
 289                         truncate_pagecache(inode, attr->size);
 290                         if (!fc->explicit_inval_data)
 291                                 inval = true;
 292                 } else if (fc->auto_inval_data) {
 293                         struct timespec64 new_mtime = {
 294                                 .tv_sec = attr->mtime,
 295                                 .tv_nsec = attr->mtimensec,
 296                         };
 297
 298                         /*
 299                          * Auto inval mode also checks and invalidates if mtime
 300                          * has changed.
 301                          */
 302                         if (!timespec64_equal(&old_mtime, &new_mtime))
 303                                 inval = true;
 304                 }
 305
 306                 if (inval)
 307                         invalidate_inode_pages2(inode->i_mapping);
 308         }
 309
 310         if (IS_ENABLED(CONFIG_FUSE_DAX))
 311                 fuse_dax_dontcache(inode, attr->flags);
 312 }
 313
 314 static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr)
 315 {
 316         inode->i_mode = attr->mode & S_IFMT;
 317         inode->i_size = attr->size;
 318         inode->i_mtime.tv_sec  = attr->mtime;
 319         inode->i_mtime.tv_nsec = attr->mtimensec;
 320         inode->i_ctime.tv_sec  = attr->ctime;
 321         inode->i_ctime.tv_nsec = attr->ctimensec;
 322         if (S_ISREG(inode->i_mode)) {
 323                 fuse_init_common(inode);
 324                 fuse_init_file_inode(inode, attr->flags);
 325         } else if (S_ISDIR(inode->i_mode))
 326                 fuse_init_dir(inode);
 327         else if (S_ISLNK(inode->i_mode))
 328                 fuse_init_symlink(inode);
 329         else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
 330                  S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
 331                 fuse_init_common(inode);
 332                 init_special_inode(inode, inode->i_mode,
 333                                    new_decode_dev(attr->rdev));
 334         } else
 335                 BUG();
 336 }
 337
 338 static int fuse_inode_eq(struct inode *inode, void *_nodeidp)
 339 {
 340         u64 nodeid = *(u64 *) _nodeidp;
 341         if (get_node_id(inode) == nodeid)
 342                 return 1;
 343         else
 344                 return 0;
 345 }
 346
 347 static int fuse_inode_set(struct inode *inode, void *_nodeidp)
 348 {
 349         u64 nodeid = *(u64 *) _nodeidp;
 350         get_fuse_inode(inode)->nodeid = nodeid;
 351         return 0;
 352 }
 353
 354 struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
 355                         int generation, struct fuse_attr *attr,
 356                         u64 attr_valid, u64 attr_version)
 357 {
 358         struct inode *inode;
 359         struct fuse_inode *fi;
 360         struct fuse_conn *fc = get_fuse_conn_super(sb);
 361
 362         /*
 363          * Auto mount points get their node id from the submount root, which is
 364          * not a unique identifier within this filesystem.
 365          *
 366          * To avoid conflicts, do not place submount points into the inode hash
 367          * table.
 368          */
 369         if (fc->auto_submounts && (attr->flags & FUSE_ATTR_SUBMOUNT) &&
 370             S_ISDIR(attr->mode)) {
 371                 inode = new_inode(sb);
 372                 if (!inode)
 373                         return NULL;
 374
 375                 fuse_init_inode(inode, attr);
 376                 get_fuse_inode(inode)->nodeid = nodeid;
 377                 inode->i_flags |= S_AUTOMOUNT;
 378                 goto done;
 379         }
 380
 381 retry:
 382         inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid);
 383         if (!inode)
 384                 return NULL;
 385
 386         if ((inode->i_state & I_NEW)) {
 387                 inode->i_flags |= S_NOATIME;
 388                 if (!fc->writeback_cache || !S_ISREG(attr->mode))
 389                         inode->i_flags |= S_NOCMTIME;
 390                 inode->i_generation = generation;
 391                 fuse_init_inode(inode, attr);
 392                 unlock_new_inode(inode);
 393         } else if (fuse_stale_inode(inode, generation, attr)) {
 394                 /* nodeid was reused, any I/O on the old inode should fail */
 395                 fuse_make_bad(inode);
 396                 iput(inode);
 397                 goto retry;
 398         }
 399 done:
 400         fi = get_fuse_inode(inode);
 401         spin_lock(&fi->lock);
 402         fi->nlookup++;
 403         spin_unlock(&fi->lock);
 404         fuse_change_attributes(inode, attr, attr_valid, attr_version);
 405
 406         return inode;
 407 }
 408
 409 struct inode *fuse_ilookup(struct fuse_conn *fc, u64 nodeid,
 410                            struct fuse_mount **fm)
 411 {
 412         struct fuse_mount *fm_iter;
 413         struct inode *inode;
 414
 415         WARN_ON(!rwsem_is_locked(&fc->killsb));
 416         list_for_each_entry(fm_iter, &fc->mounts, fc_entry) {
 417                 if (!fm_iter->sb)
 418                         continue;
 419
 420                 inode = ilookup5(fm_iter->sb, nodeid, fuse_inode_eq, &nodeid);
 421                 if (inode) {
 422                         if (fm)
 423                                 *fm = fm_iter;
 424                         return inode;
 425                 }
 426         }
 427
 428         return NULL;
 429 }
 430
 431 int fuse_reverse_inval_inode(struct fuse_conn *fc, u64 nodeid,
 432                              loff_t offset, loff_t len)
 433 {
 434         struct fuse_inode *fi;
 435         struct inode *inode;
 436         pgoff_t pg_start;
 437         pgoff_t pg_end;
 438
 439         inode = fuse_ilookup(fc, nodeid, NULL);
 440         if (!inode)
 441                 return -ENOENT;
 442
 443         fi = get_fuse_inode(inode);
 444         spin_lock(&fi->lock);
 445         fi->attr_version = atomic64_inc_return(&fc->attr_version);
 446         spin_unlock(&fi->lock);
 447
 448         fuse_invalidate_attr(inode);
 449         forget_all_cached_acls(inode);
 450         if (offset >= 0) {
 451                 pg_start = offset >> PAGE_SHIFT;
 452                 if (len <= 0)
 453                         pg_end = -1;
 454                 else
 455                         pg_end = (offset + len - 1) >> PAGE_SHIFT;
 456                 invalidate_inode_pages2_range(inode->i_mapping,
 457                                               pg_start, pg_end);
 458         }
 459         iput(inode);
 460         return 0;
 461 }
 462
 463 bool fuse_lock_inode(struct inode *inode)
 464 {
 465         bool locked = false;
 466
 467         if (!get_fuse_conn(inode)->parallel_dirops) {
 468                 mutex_lock(&get_fuse_inode(inode)->mutex);
 469                 locked = true;
 470         }
 471
 472         return locked;
 473 }
 474
 475 void fuse_unlock_inode(struct inode *inode, bool locked)
 476 {
 477         if (locked)
 478                 mutex_unlock(&get_fuse_inode(inode)->mutex);
 479 }
 480
 481 static void fuse_umount_begin(struct super_block *sb)
 482 {
 483         struct fuse_conn *fc = get_fuse_conn_super(sb);
 484
 485         if (fc->no_force_umount)
 486                 return;
 487
 488         fuse_abort_conn(fc);
 489
 490         // Only retire block-device-based superblocks.
 491         if (sb->s_bdev != NULL)
 492                 retire_super(sb);
 493 }
 494
 495 static void fuse_send_destroy(struct fuse_mount *fm)
 496 {
 497         if (fm->fc->conn_init) {
 498                 FUSE_ARGS(args);
 499
 500                 args.opcode = FUSE_DESTROY;
 501                 args.force = true;
 502                 args.nocreds = true;
 503                 fuse_simple_request(fm, &args);
 504         }
 505 }
 506
 507 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr)
 508 {
 509         stbuf->f_type    = FUSE_SUPER_MAGIC;
 510         stbuf->f_bsize   = attr->bsize;
 511         stbuf->f_frsize  = attr->frsize;
 512         stbuf->f_blocks  = attr->blocks;
 513         stbuf->f_bfree   = attr->bfree;
 514         stbuf->f_bavail  = attr->bavail;
 515         stbuf->f_files   = attr->files;
 516         stbuf->f_ffree   = attr->ffree;
 517         stbuf->f_namelen = attr->namelen;
 518         /* fsid is left zero */
 519 }
 520
 521 static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf)
 522 {
 523         struct super_block *sb = dentry->d_sb;
 524         struct fuse_mount *fm = get_fuse_mount_super(sb);
 525         FUSE_ARGS(args);
 526         struct fuse_statfs_out outarg;
 527         int err;
 528
 529         if (!fuse_allow_current_process(fm->fc)) {
 530                 buf->f_type = FUSE_SUPER_MAGIC;
 531                 return 0;
 532         }
 533
 534         memset(&outarg, 0, sizeof(outarg));
 535         args.in_numargs = 0;
 536         args.opcode = FUSE_STATFS;
 537         args.nodeid = get_node_id(d_inode(dentry));
 538         args.out_numargs = 1;
 539         args.out_args[0].size = sizeof(outarg);
 540         args.out_args[0].value = &outarg;
 541         err = fuse_simple_request(fm, &args);
 542         if (!err)
 543                 convert_fuse_statfs(buf, &outarg.st);
 544         return err;
 545 }
 546
 547 static struct fuse_sync_bucket *fuse_sync_bucket_alloc(void)
 548 {
 549         struct fuse_sync_bucket *bucket;
 550
 551         bucket = kzalloc(sizeof(*bucket), GFP_KERNEL | __GFP_NOFAIL);
 552         if (bucket) {
 553                 init_waitqueue_head(&bucket->waitq);
 554                 /* Initial active count */
 555                 atomic_set(&bucket->count, 1);
 556         }
 557         return bucket;
 558 }
 559
 560 static void fuse_sync_fs_writes(struct fuse_conn *fc)
 561 {
 562         struct fuse_sync_bucket *bucket, *new_bucket;
 563         int count;
 564
 565         new_bucket = fuse_sync_bucket_alloc();
 566         spin_lock(&fc->lock);
 567         bucket = rcu_dereference_protected(fc->curr_bucket, 1);
 568         count = atomic_read(&bucket->count);
 569         WARN_ON(count < 1);
 570         /* No outstanding writes? */
 571         if (count == 1) {
 572                 spin_unlock(&fc->lock);
 573                 kfree(new_bucket);
 574                 return;
 575         }
 576
 577         /*
 578          * Completion of new bucket depends on completion of this bucket, so add
 579          * one more count.
 580          */
 581         atomic_inc(&new_bucket->count);
 582         rcu_assign_pointer(fc->curr_bucket, new_bucket);
 583         spin_unlock(&fc->lock);
 584         /*
 585          * Drop initial active count.  At this point if all writes in this and
 586          * ancestor buckets complete, the count will go to zero and this task
 587          * will be woken up.
 588          */
 589         atomic_dec(&bucket->count);
 590
 591         wait_event(bucket->waitq, atomic_read(&bucket->count) == 0);
 592
 593         /* Drop temp count on descendant bucket */
 594         fuse_sync_bucket_dec(new_bucket);
 595         kfree_rcu(bucket, rcu);
 596 }
 597
 598 static int fuse_sync_fs(struct super_block *sb, int wait)
 599 {
 600         struct fuse_mount *fm = get_fuse_mount_super(sb);
 601         struct fuse_conn *fc = fm->fc;
 602         struct fuse_syncfs_in inarg;
 603         FUSE_ARGS(args);
 604         int err;
 605
 606         /*
 607          * Userspace cannot handle the wait == 0 case.  Avoid a
 608          * gratuitous roundtrip.
 609          */
 610         if (!wait)
 611                 return 0;
 612
 613         /* The filesystem is being unmounted.  Nothing to do. */
 614         if (!sb->s_root)
 615                 return 0;
 616
 617         if (!fc->sync_fs)
 618                 return 0;
 619
 620         fuse_sync_fs_writes(fc);
 621
 622         memset(&inarg, 0, sizeof(inarg));
 623         args.in_numargs = 1;
 624         args.in_args[0].size = sizeof(inarg);
 625         args.in_args[0].value = &inarg;
 626         args.opcode = FUSE_SYNCFS;
 627         args.nodeid = get_node_id(sb->s_root->d_inode);
 628         args.out_numargs = 0;
 629
 630         err = fuse_simple_request(fm, &args);
 631         if (err == -ENOSYS) {
 632                 fc->sync_fs = 0;
 633                 err = 0;
 634         }
 635
 636         return err;
 637 }
 638
 639 enum {
 640         OPT_SOURCE,
 641         OPT_SUBTYPE,
 642         OPT_FD,
 643         OPT_ROOTMODE,
 644         OPT_USER_ID,
 645         OPT_GROUP_ID,
 646         OPT_DEFAULT_PERMISSIONS,
 647         OPT_ALLOW_OTHER,
 648         OPT_MAX_READ,
 649         OPT_BLKSIZE,
 650         OPT_ERR
 651 };
 652
 653 static const struct fs_parameter_spec fuse_fs_parameters[] = {
 654         fsparam_string  ("source",              OPT_SOURCE),
 655         fsparam_u32     ("fd",                  OPT_FD),
 656         fsparam_u32oct  ("rootmode",            OPT_ROOTMODE),
 657         fsparam_u32     ("user_id",             OPT_USER_ID),
 658         fsparam_u32     ("group_id",            OPT_GROUP_ID),
 659         fsparam_flag    ("default_permissions", OPT_DEFAULT_PERMISSIONS),
 660         fsparam_flag    ("allow_other",         OPT_ALLOW_OTHER),
 661         fsparam_u32     ("max_read",            OPT_MAX_READ),
 662         fsparam_u32     ("blksize",             OPT_BLKSIZE),
 663         fsparam_string  ("subtype",             OPT_SUBTYPE),
 664         {}
 665 };
 666
 667 static int fuse_parse_param(struct fs_context *fsc, struct fs_parameter *param)
 668 {
 669         struct fs_parse_result result;
 670         struct fuse_fs_context *ctx = fsc->fs_private;
 671         int opt;
 672
 673         if (fsc->purpose == FS_CONTEXT_FOR_RECONFIGURE) {
 674                 /*
 675                  * Ignore options coming from mount(MS_REMOUNT) for backward
 676                  * compatibility.
 677                  */
 678                 if (fsc->oldapi)
 679                         return 0;
 680
 681                 return invalfc(fsc, "No changes allowed in reconfigure");
 682         }
 683
 684         opt = fs_parse(fsc, fuse_fs_parameters, param, &result);
 685         if (opt < 0)
 686                 return opt;
 687
 688         switch (opt) {
 689         case OPT_SOURCE:
 690                 if (fsc->source)
 691                         return invalfc(fsc, "Multiple sources specified");
 692                 fsc->source = param->string;
 693                 param->string = NULL;
 694                 break;
 695
 696         case OPT_SUBTYPE:
 697                 if (ctx->subtype)
 698                         return invalfc(fsc, "Multiple subtypes specified");
 699                 ctx->subtype = param->string;
 700                 param->string = NULL;
 701                 return 0;
 702
 703         case OPT_FD:
 704                 ctx->fd = result.uint_32;
 705                 ctx->fd_present = true;
 706                 break;
 707
 708         case OPT_ROOTMODE:
 709                 if (!fuse_valid_type(result.uint_32))
 710                         return invalfc(fsc, "Invalid rootmode");
 711                 ctx->rootmode = result.uint_32;
 712                 ctx->rootmode_present = true;
 713                 break;
 714
 715         case OPT_USER_ID:
 716                 ctx->user_id = make_kuid(fsc->user_ns, result.uint_32);
 717                 if (!uid_valid(ctx->user_id))
 718                         return invalfc(fsc, "Invalid user_id");
 719                 ctx->user_id_present = true;
 720                 break;
 721
 722         case OPT_GROUP_ID:
 723                 ctx->group_id = make_kgid(fsc->user_ns, result.uint_32);
 724                 if (!gid_valid(ctx->group_id))
 725                         return invalfc(fsc, "Invalid group_id");
 726                 ctx->group_id_present = true;
 727                 break;
 728
 729         case OPT_DEFAULT_PERMISSIONS:
 730                 ctx->default_permissions = true;
 731                 break;
 732
 733         case OPT_ALLOW_OTHER:
 734                 ctx->allow_other = true;
 735                 break;
 736
 737         case OPT_MAX_READ:
 738                 ctx->max_read = result.uint_32;
 739                 break;
 740
 741         case OPT_BLKSIZE:
 742                 if (!ctx->is_bdev)
 743                         return invalfc(fsc, "blksize only supported for fuseblk");
 744                 ctx->blksize = result.uint_32;
 745                 break;
 746
 747         default:
 748                 return -EINVAL;
 749         }
 750
 751         return 0;
 752 }
 753
 754 static void fuse_free_fsc(struct fs_context *fsc)
 755 {
 756         struct fuse_fs_context *ctx = fsc->fs_private;
 757
 758         if (ctx) {
 759                 kfree(ctx->subtype);
 760                 kfree(ctx);
 761         }
 762 }
 763
 764 static int fuse_show_options(struct seq_file *m, struct dentry *root)
 765 {
 766         struct super_block *sb = root->d_sb;
 767         struct fuse_conn *fc = get_fuse_conn_super(sb);
 768
 769         if (fc->legacy_opts_show) {
 770                 seq_printf(m, ",user_id=%u",
 771                            from_kuid_munged(fc->user_ns, fc->user_id));
 772                 seq_printf(m, ",group_id=%u",
 773                            from_kgid_munged(fc->user_ns, fc->group_id));
 774                 if (fc->default_permissions)
 775                         seq_puts(m, ",default_permissions");
 776                 if (fc->allow_other)
 777                         seq_puts(m, ",allow_other");
 778                 if (fc->max_read != ~0)
 779                         seq_printf(m, ",max_read=%u", fc->max_read);
 780                 if (sb->s_bdev && sb->s_blocksize != FUSE_DEFAULT_BLKSIZE)
 781                         seq_printf(m, ",blksize=%lu", sb->s_blocksize);
 782         }
 783 #ifdef CONFIG_FUSE_DAX
 784         if (fc->dax_mode == FUSE_DAX_ALWAYS)
 785                 seq_puts(m, ",dax=always");
 786         else if (fc->dax_mode == FUSE_DAX_NEVER)
 787                 seq_puts(m, ",dax=never");
 788         else if (fc->dax_mode == FUSE_DAX_INODE_USER)
 789                 seq_puts(m, ",dax=inode");
 790 #endif
 791
 792         return 0;
 793 }
 794
 795 static void fuse_iqueue_init(struct fuse_iqueue *fiq,
 796                              const struct fuse_iqueue_ops *ops,
 797                              void *priv)
 798 {
 799         memset(fiq, 0, sizeof(struct fuse_iqueue));
 800         spin_lock_init(&fiq->lock);
 801         init_waitqueue_head(&fiq->waitq);
 802         INIT_LIST_HEAD(&fiq->pending);
 803         INIT_LIST_HEAD(&fiq->interrupts);
 804         fiq->forget_list_tail = &fiq->forget_list_head;
 805         fiq->connected = 1;
 806         fiq->ops = ops;
 807         fiq->priv = priv;
 808 }
 809
 810 static void fuse_pqueue_init(struct fuse_pqueue *fpq)
 811 {
 812         unsigned int i;
 813
 814         spin_lock_init(&fpq->lock);
 815         for (i = 0; i < FUSE_PQ_HASH_SIZE; i++)
 816                 INIT_LIST_HEAD(&fpq->processing[i]);
 817         INIT_LIST_HEAD(&fpq->io);
 818         fpq->connected = 1;
 819 }
 820
 821 void fuse_conn_init(struct fuse_conn *fc, struct fuse_mount *fm,
 822                     struct user_namespace *user_ns,
 823                     const struct fuse_iqueue_ops *fiq_ops, void *fiq_priv)
 824 {
 825         memset(fc, 0, sizeof(*fc));
 826         spin_lock_init(&fc->lock);
 827         spin_lock_init(&fc->bg_lock);
 828         init_rwsem(&fc->killsb);
 829         refcount_set(&fc->count, 1);
 830         atomic_set(&fc->dev_count, 1);
 831         init_waitqueue_head(&fc->blocked_waitq);
 832         fuse_iqueue_init(&fc->iq, fiq_ops, fiq_priv);
 833         INIT_LIST_HEAD(&fc->bg_queue);
 834         INIT_LIST_HEAD(&fc->entry);
 835         INIT_LIST_HEAD(&fc->devices);
 836         atomic_set(&fc->num_waiting, 0);
 837         fc->max_background = FUSE_DEFAULT_MAX_BACKGROUND;
 838         fc->congestion_threshold = FUSE_DEFAULT_CONGESTION_THRESHOLD;
 839         atomic64_set(&fc->khctr, 0);
 840         fc->polled_files = RB_ROOT;
 841         fc->blocked = 0;
 842         fc->initialized = 0;
 843         fc->connected = 1;
 844         atomic64_set(&fc->attr_version, 1);
 845         get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key));
 846         fc->pid_ns = get_pid_ns(task_active_pid_ns(current));
 847         fc->user_ns = get_user_ns(user_ns);
 848         fc->max_pages = FUSE_DEFAULT_MAX_PAGES_PER_REQ;
 849         fc->max_pages_limit = FUSE_MAX_MAX_PAGES;
 850
 851         INIT_LIST_HEAD(&fc->mounts);
 852         list_add(&fm->fc_entry, &fc->mounts);
 853         fm->fc = fc;
 854 }
 855 EXPORT_SYMBOL_GPL(fuse_conn_init);
 856
 857 void fuse_conn_put(struct fuse_conn *fc)
 858 {
 859         if (refcount_dec_and_test(&fc->count)) {
 860                 struct fuse_iqueue *fiq = &fc->iq;
 861                 struct fuse_sync_bucket *bucket;
 862
 863                 if (IS_ENABLED(CONFIG_FUSE_DAX))
 864                         fuse_dax_conn_free(fc);
 865                 if (fiq->ops->release)
 866                         fiq->ops->release(fiq);
 867                 put_pid_ns(fc->pid_ns);
 868                 put_user_ns(fc->user_ns);
 869                 bucket = rcu_dereference_protected(fc->curr_bucket, 1);
 870                 if (bucket) {
 871                         WARN_ON(atomic_read(&bucket->count) != 1);
 872                         kfree(bucket);
 873                 }
 874                 fc->release(fc);
 875         }
 876 }
 877 EXPORT_SYMBOL_GPL(fuse_conn_put);
 878
 879 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc)
 880 {
 881         refcount_inc(&fc->count);
 882         return fc;
 883 }
 884 EXPORT_SYMBOL_GPL(fuse_conn_get);
 885
 886 static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned mode)
 887 {
 888         struct fuse_attr attr;
 889         memset(&attr, 0, sizeof(attr));
 890
 891         attr.mode = mode;
 892         attr.ino = FUSE_ROOT_ID;
 893         attr.nlink = 1;
 894         return fuse_iget(sb, 1, 0, &attr, 0, 0);
 895 }
 896
 897 struct fuse_inode_handle {
 898         u64 nodeid;
 899         u32 generation;
 900 };
 901
 902 static struct dentry *fuse_get_dentry(struct super_block *sb,
 903                                       struct fuse_inode_handle *handle)
 904 {
 905         struct fuse_conn *fc = get_fuse_conn_super(sb);
 906         struct inode *inode;
 907         struct dentry *entry;
 908         int err = -ESTALE;
 909
 910         if (handle->nodeid == 0)
 911                 goto out_err;
 912
 913         inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid);
 914         if (!inode) {
 915                 struct fuse_entry_out outarg;
 916                 const struct qstr name = QSTR_INIT(".", 1);
 917
 918                 if (!fc->export_support)
 919                         goto out_err;
 920
 921                 err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg,
 922                                        &inode);
 923                 if (err && err != -ENOENT)
 924                         goto out_err;
 925                 if (err || !inode) {
 926                         err = -ESTALE;
 927                         goto out_err;
 928                 }
 929                 err = -EIO;
 930                 if (get_node_id(inode) != handle->nodeid)
 931                         goto out_iput;
 932         }
 933         err = -ESTALE;
 934         if (inode->i_generation != handle->generation)
 935                 goto out_iput;
 936
 937         entry = d_obtain_alias(inode);
 938         if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID)
 939                 fuse_invalidate_entry_cache(entry);
 940
 941         return entry;
 942
 943  out_iput:
 944         iput(inode);
 945  out_err:
 946         return ERR_PTR(err);
 947 }
 948
 949 static int fuse_encode_fh(struct inode *inode, u32 *fh, int *max_len,
 950                            struct inode *parent)
 951 {
 952         int len = parent ? 6 : 3;
 953         u64 nodeid;
 954         u32 generation;
 955
 956         if (*max_len < len) {
 957                 *max_len = len;
 958                 return  FILEID_INVALID;
 959         }
 960
 961         nodeid = get_fuse_inode(inode)->nodeid;
 962         generation = inode->i_generation;
 963
 964         fh[0] = (u32)(nodeid >> 32);
 965         fh[1] = (u32)(nodeid & 0xffffffff);
 966         fh[2] = generation;
 967
 968         if (parent) {
 969                 nodeid = get_fuse_inode(parent)->nodeid;
 970                 generation = parent->i_generation;
 971
 972                 fh[3] = (u32)(nodeid >> 32);
 973                 fh[4] = (u32)(nodeid & 0xffffffff);
 974                 fh[5] = generation;
 975         }
 976
 977         *max_len = len;
 978         return parent ? 0x82 : 0x81;
 979 }
 980
 981 static struct dentry *fuse_fh_to_dentry(struct super_block *sb,
 982                 struct fid *fid, int fh_len, int fh_type)
 983 {
 984         struct fuse_inode_handle handle;
 985
 986         if ((fh_type != 0x81 && fh_type != 0x82) || fh_len < 3)
 987                 return NULL;
 988
 989         handle.nodeid = (u64) fid->raw[0] << 32;
 990         handle.nodeid |= (u64) fid->raw[1];
 991         handle.generation = fid->raw[2];
 992         return fuse_get_dentry(sb, &handle);
 993 }
 994
 995 static struct dentry *fuse_fh_to_parent(struct super_block *sb,
 996                 struct fid *fid, int fh_len, int fh_type)
 997 {
 998         struct fuse_inode_handle parent;
 999
1000         if (fh_type != 0x82 || fh_len < 6)
1001                 return NULL;
1002
1003         parent.nodeid = (u64) fid->raw[3] << 32;
1004         parent.nodeid |= (u64) fid->raw[4];
1005         parent.generation = fid->raw[5];
1006         return fuse_get_dentry(sb, &parent);
1007 }
1008
1009 static struct dentry *fuse_get_parent(struct dentry *child)
1010 {
1011         struct inode *child_inode = d_inode(child);
1012         struct fuse_conn *fc = get_fuse_conn(child_inode);
1013         struct inode *inode;
1014         struct dentry *parent;
1015         struct fuse_entry_out outarg;
1016         int err;
1017
1018         if (!fc->export_support)
1019                 return ERR_PTR(-ESTALE);
1020
1021         err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode),
1022                                &dotdot_name, &outarg, &inode);
1023         if (err) {
1024                 if (err == -ENOENT)
1025                         return ERR_PTR(-ESTALE);
1026                 return ERR_PTR(err);
1027         }
1028
1029         parent = d_obtain_alias(inode);
1030         if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID)
1031                 fuse_invalidate_entry_cache(parent);
1032
1033         return parent;
1034 }
1035
1036 static const struct export_operations fuse_export_operations = {
1037         .fh_to_dentry   = fuse_fh_to_dentry,
1038         .fh_to_parent   = fuse_fh_to_parent,
1039         .encode_fh      = fuse_encode_fh,
1040         .get_parent     = fuse_get_parent,
1041 };
1042
1043 static const struct super_operations fuse_super_operations = {
1044         .alloc_inode    = fuse_alloc_inode,
1045         .free_inode     = fuse_free_inode,
1046         .evict_inode    = fuse_evict_inode,
1047         .write_inode    = fuse_write_inode,
1048         .drop_inode     = generic_delete_inode,
1049         .umount_begin   = fuse_umount_begin,
1050         .statfs         = fuse_statfs,
1051         .sync_fs        = fuse_sync_fs,
1052         .show_options   = fuse_show_options,
1053 };
1054
1055 static void sanitize_global_limit(unsigned *limit)
1056 {
1057         /*
1058          * The default maximum number of async requests is calculated to consume
1059          * 1/2^13 of the total memory, assuming 392 bytes per request.
1060          */
1061         if (*limit == 0)
1062                 *limit = ((totalram_pages() << PAGE_SHIFT) >> 13) / 392;
1063
1064         if (*limit >= 1 << 16)
1065                 *limit = (1 << 16) - 1;
1066 }
1067
1068 static int set_global_limit(const char *val, const struct kernel_param *kp)
1069 {
1070         int rv;
1071
1072         rv = param_set_uint(val, kp);
1073         if (rv)
1074                 return rv;
1075
1076         sanitize_global_limit((unsigned *)kp->arg);
1077
1078         return 0;
1079 }
1080
1081 static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg)
1082 {
1083         int cap_sys_admin = capable(CAP_SYS_ADMIN);
1084
1085         if (arg->minor < 13)
1086                 return;
1087
1088         sanitize_global_limit(&max_user_bgreq);
1089         sanitize_global_limit(&max_user_congthresh);
1090
1091         spin_lock(&fc->bg_lock);
1092         if (arg->max_background) {
1093                 fc->max_background = arg->max_background;
1094
1095                 if (!cap_sys_admin && fc->max_background > max_user_bgreq)
1096                         fc->max_background = max_user_bgreq;
1097         }
1098         if (arg->congestion_threshold) {
1099                 fc->congestion_threshold = arg->congestion_threshold;
1100
1101                 if (!cap_sys_admin &&
1102                     fc->congestion_threshold > max_user_congthresh)
1103                         fc->congestion_threshold = max_user_congthresh;
1104         }
1105         spin_unlock(&fc->bg_lock);
1106 }
1107
1108 struct fuse_init_args {
1109         struct fuse_args args;
1110         struct fuse_init_in in;
1111         struct fuse_init_out out;
1112 };
1113
1114 static void process_init_reply(struct fuse_mount *fm, struct fuse_args *args,
1115                                int error)
1116 {
1117         struct fuse_conn *fc = fm->fc;
1118         struct fuse_init_args *ia = container_of(args, typeof(*ia), args);
1119         struct fuse_init_out *arg = &ia->out;
1120         bool ok = true;
1121
1122         if (error || arg->major != FUSE_KERNEL_VERSION)
1123                 ok = false;
1124         else {
1125                 unsigned long ra_pages;
1126
1127                 process_init_limits(fc, arg);
1128
1129                 if (arg->minor >= 6) {
1130                         u64 flags = arg->flags | (u64) arg->flags2 << 32;
1131
1132                         ra_pages = arg->max_readahead / PAGE_SIZE;
1133                         if (flags & FUSE_ASYNC_READ)
1134                                 fc->async_read = 1;
1135                         if (!(flags & FUSE_POSIX_LOCKS))
1136                                 fc->no_lock = 1;
1137                         if (arg->minor >= 17) {
1138                                 if (!(flags & FUSE_FLOCK_LOCKS))
1139                                         fc->no_flock = 1;
1140                         } else {
1141                                 if (!(flags & FUSE_POSIX_LOCKS))
1142                                         fc->no_flock = 1;
1143                         }
1144                         if (flags & FUSE_ATOMIC_O_TRUNC)
1145                                 fc->atomic_o_trunc = 1;
1146                         if (arg->minor >= 9) {
1147                                 /* LOOKUP has dependency on proto version */
1148                                 if (flags & FUSE_EXPORT_SUPPORT)
1149                                         fc->export_support = 1;
1150                         }
1151                         if (flags & FUSE_BIG_WRITES)
1152                                 fc->big_writes = 1;
1153                         if (flags & FUSE_DONT_MASK)
1154                                 fc->dont_mask = 1;
1155                         if (flags & FUSE_AUTO_INVAL_DATA)
1156                                 fc->auto_inval_data = 1;
1157                         else if (flags & FUSE_EXPLICIT_INVAL_DATA)
1158                                 fc->explicit_inval_data = 1;
1159                         if (flags & FUSE_DO_READDIRPLUS) {
1160                                 fc->do_readdirplus = 1;
1161                                 if (flags & FUSE_READDIRPLUS_AUTO)
1162                                         fc->readdirplus_auto = 1;
1163                         }
1164                         if (flags & FUSE_ASYNC_DIO)
1165                                 fc->async_dio = 1;
1166                         if (flags & FUSE_WRITEBACK_CACHE)
1167                                 fc->writeback_cache = 1;
1168                         if (flags & FUSE_PARALLEL_DIROPS)
1169                                 fc->parallel_dirops = 1;
1170                         if (flags & FUSE_HANDLE_KILLPRIV)
1171                                 fc->handle_killpriv = 1;
1172                         if (arg->time_gran && arg->time_gran <= 1000000000)
1173                                 fm->sb->s_time_gran = arg->time_gran;
1174                         if ((flags & FUSE_POSIX_ACL)) {
1175                                 fc->default_permissions = 1;
1176                                 fc->posix_acl = 1;
1177                                 fm->sb->s_xattr = fuse_acl_xattr_handlers;
1178                         }
1179                         if (flags & FUSE_CACHE_SYMLINKS)
1180                                 fc->cache_symlinks = 1;
1181                         if (flags & FUSE_ABORT_ERROR)
1182                                 fc->abort_err = 1;
1183                         if (flags & FUSE_MAX_PAGES) {
1184                                 fc->max_pages =
1185                                         min_t(unsigned int, fc->max_pages_limit,
1186                                         max_t(unsigned int, arg->max_pages, 1));
1187                         }
1188                         if (IS_ENABLED(CONFIG_FUSE_DAX)) {
1189                                 if (flags & FUSE_MAP_ALIGNMENT &&
1190                                     !fuse_dax_check_alignment(fc, arg->map_alignment)) {
1191                                         ok = false;
1192                                 }
1193                                 if (flags & FUSE_HAS_INODE_DAX)
1194                                         fc->inode_dax = 1;
1195                         }
1196                         if (flags & FUSE_HANDLE_KILLPRIV_V2) {
1197                                 fc->handle_killpriv_v2 = 1;
1198                                 fm->sb->s_flags |= SB_NOSEC;
1199                         }
1200                         if (flags & FUSE_SETXATTR_EXT)
1201                                 fc->setxattr_ext = 1;
1202                         if (flags & FUSE_SECURITY_CTX)
1203                                 fc->init_security = 1;
1204                 } else {
1205                         ra_pages = fc->max_read / PAGE_SIZE;
1206                         fc->no_lock = 1;
1207                         fc->no_flock = 1;
1208                 }
1209
1210                 fm->sb->s_bdi->ra_pages =
1211                                 min(fm->sb->s_bdi->ra_pages, ra_pages);
1212                 fc->minor = arg->minor;
1213                 fc->max_write = arg->minor < 5 ? 4096 : arg->max_write;
1214                 fc->max_write = max_t(unsigned, 4096, fc->max_write);
1215                 fc->conn_init = 1;
1216         }
1217         kfree(ia);
1218
1219         if (!ok) {
1220                 fc->conn_init = 0;
1221                 fc->conn_error = 1;
1222         }
1223
1224         fuse_set_initialized(fc);
1225         wake_up_all(&fc->blocked_waitq);
1226 }
1227
1228 void fuse_send_init(struct fuse_mount *fm)
1229 {
1230         struct fuse_init_args *ia;
1231         u64 flags;
1232
1233         ia = kzalloc(sizeof(*ia), GFP_KERNEL | __GFP_NOFAIL);
1234
1235         ia->in.major = FUSE_KERNEL_VERSION;
1236         ia->in.minor = FUSE_KERNEL_MINOR_VERSION;
1237         ia->in.max_readahead = fm->sb->s_bdi->ra_pages * PAGE_SIZE;
1238         flags =
1239                 FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC |
1240                 FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK |
1241                 FUSE_SPLICE_WRITE | FUSE_SPLICE_MOVE | FUSE_SPLICE_READ |
1242                 FUSE_FLOCK_LOCKS | FUSE_HAS_IOCTL_DIR | FUSE_AUTO_INVAL_DATA |
1243                 FUSE_DO_READDIRPLUS | FUSE_READDIRPLUS_AUTO | FUSE_ASYNC_DIO |
1244                 FUSE_WRITEBACK_CACHE | FUSE_NO_OPEN_SUPPORT |
1245                 FUSE_PARALLEL_DIROPS | FUSE_HANDLE_KILLPRIV | FUSE_POSIX_ACL |
1246                 FUSE_ABORT_ERROR | FUSE_MAX_PAGES | FUSE_CACHE_SYMLINKS |
1247                 FUSE_NO_OPENDIR_SUPPORT | FUSE_EXPLICIT_INVAL_DATA |
1248                 FUSE_HANDLE_KILLPRIV_V2 | FUSE_SETXATTR_EXT | FUSE_INIT_EXT |
1249                 FUSE_SECURITY_CTX;
1250 #ifdef CONFIG_FUSE_DAX
1251         if (fm->fc->dax)
1252                 flags |= FUSE_MAP_ALIGNMENT;
1253         if (fuse_is_inode_dax_mode(fm->fc->dax_mode))
1254                 flags |= FUSE_HAS_INODE_DAX;
1255 #endif
1256         if (fm->fc->auto_submounts)
1257                 flags |= FUSE_SUBMOUNTS;
1258
1259         ia->in.flags = flags;
1260         ia->in.flags2 = flags >> 32;
1261
1262         ia->args.opcode = FUSE_INIT;
1263         ia->args.in_numargs = 1;
1264         ia->args.in_args[0].size = sizeof(ia->in);
1265         ia->args.in_args[0].value = &ia->in;
1266         ia->args.out_numargs = 1;
1267         /* Variable length argument used for backward compatibility
1268            with interface version < 7.5.  Rest of init_out is zeroed
1269            by do_get_request(), so a short reply is not a problem */
1270         ia->args.out_argvar = true;
1271         ia->args.out_args[0].size = sizeof(ia->out);
1272         ia->args.out_args[0].value = &ia->out;
1273         ia->args.force = true;
1274         ia->args.nocreds = true;
1275         ia->args.end = process_init_reply;
1276
1277         if (fuse_simple_background(fm, &ia->args, GFP_KERNEL) != 0)
1278                 process_init_reply(fm, &ia->args, -ENOTCONN);
1279 }
1280 EXPORT_SYMBOL_GPL(fuse_send_init);
1281
1282 void fuse_free_conn(struct fuse_conn *fc)
1283 {
1284         WARN_ON(!list_empty(&fc->devices));
1285         kfree_rcu(fc, rcu);
1286 }
1287 EXPORT_SYMBOL_GPL(fuse_free_conn);
1288
1289 static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
1290 {
1291         int err;
1292         char *suffix = "";
1293
1294         if (sb->s_bdev) {
1295                 suffix = "-fuseblk";
1296                 /*
1297                  * sb->s_bdi points to blkdev's bdi however we want to redirect
1298                  * it to our private bdi...
1299                  */
1300                 bdi_put(sb->s_bdi);
1301                 sb->s_bdi = &noop_backing_dev_info;
1302         }
1303         err = super_setup_bdi_name(sb, "%u:%u%s", MAJOR(fc->dev),
1304                                    MINOR(fc->dev), suffix);
1305         if (err)
1306                 return err;
1307
1308         /* fuse does it's own writeback accounting */
1309         sb->s_bdi->capabilities &= ~BDI_CAP_WRITEBACK_ACCT;
1310         sb->s_bdi->capabilities |= BDI_CAP_STRICTLIMIT;
1311
1312         /*
1313          * For a single fuse filesystem use max 1% of dirty +
1314          * writeback threshold.
1315          *
1316          * This gives about 1M of write buffer for memory maps on a
1317          * machine with 1G and 10% dirty_ratio, which should be more
1318          * than enough.
1319          *
1320          * Privileged users can raise it by writing to
1321          *
1322          *    /sys/class/bdi/<bdi>/max_ratio
1323          */
1324         bdi_set_max_ratio(sb->s_bdi, 1);
1325
1326         return 0;
1327 }
1328
1329 struct fuse_dev *fuse_dev_alloc(void)
1330 {
1331         struct fuse_dev *fud;
1332         struct list_head *pq;
1333
1334         fud = kzalloc(sizeof(struct fuse_dev), GFP_KERNEL);
1335         if (!fud)
1336                 return NULL;
1337
1338         pq = kcalloc(FUSE_PQ_HASH_SIZE, sizeof(struct list_head), GFP_KERNEL);
1339         if (!pq) {
1340                 kfree(fud);
1341                 return NULL;
1342         }
1343
1344         fud->pq.processing = pq;
1345         fuse_pqueue_init(&fud->pq);
1346
1347         return fud;
1348 }
1349 EXPORT_SYMBOL_GPL(fuse_dev_alloc);
1350
1351 void fuse_dev_install(struct fuse_dev *fud, struct fuse_conn *fc)
1352 {
1353         fud->fc = fuse_conn_get(fc);
1354         spin_lock(&fc->lock);
1355         list_add_tail(&fud->entry, &fc->devices);
1356         spin_unlock(&fc->lock);
1357 }
1358 EXPORT_SYMBOL_GPL(fuse_dev_install);
1359
1360 struct fuse_dev *fuse_dev_alloc_install(struct fuse_conn *fc)
1361 {
1362         struct fuse_dev *fud;
1363
1364         fud = fuse_dev_alloc();
1365         if (!fud)
1366                 return NULL;
1367
1368         fuse_dev_install(fud, fc);
1369         return fud;
1370 }
1371 EXPORT_SYMBOL_GPL(fuse_dev_alloc_install);
1372
1373 void fuse_dev_free(struct fuse_dev *fud)
1374 {
1375         struct fuse_conn *fc = fud->fc;
1376
1377         if (fc) {
1378                 spin_lock(&fc->lock);
1379                 list_del(&fud->entry);
1380                 spin_unlock(&fc->lock);
1381
1382                 fuse_conn_put(fc);
1383         }
1384         kfree(fud->pq.processing);
1385         kfree(fud);
1386 }
1387 EXPORT_SYMBOL_GPL(fuse_dev_free);
1388
1389 static void fuse_fill_attr_from_inode(struct fuse_attr *attr,
1390                                       const struct fuse_inode *fi)
1391 {
1392         *attr = (struct fuse_attr){
1393                 .ino            = fi->inode.i_ino,
1394                 .size           = fi->inode.i_size,
1395                 .blocks         = fi->inode.i_blocks,
1396                 .atime          = fi->inode.i_atime.tv_sec,
1397                 .mtime          = fi->inode.i_mtime.tv_sec,
1398                 .ctime          = fi->inode.i_ctime.tv_sec,
1399                 .atimensec      = fi->inode.i_atime.tv_nsec,
1400                 .mtimensec      = fi->inode.i_mtime.tv_nsec,
1401                 .ctimensec      = fi->inode.i_ctime.tv_nsec,
1402                 .mode           = fi->inode.i_mode,
1403                 .nlink          = fi->inode.i_nlink,
1404                 .uid            = fi->inode.i_uid.val,
1405                 .gid            = fi->inode.i_gid.val,
1406                 .rdev           = fi->inode.i_rdev,
1407                 .blksize        = 1u << fi->inode.i_blkbits,
1408         };
1409 }
1410
1411 static void fuse_sb_defaults(struct super_block *sb)
1412 {
1413         sb->s_magic = FUSE_SUPER_MAGIC;
1414         sb->s_op = &fuse_super_operations;
1415         sb->s_xattr = fuse_xattr_handlers;
1416         sb->s_maxbytes = MAX_LFS_FILESIZE;
1417         sb->s_time_gran = 1;
1418         sb->s_export_op = &fuse_export_operations;
1419         sb->s_iflags |= SB_I_IMA_UNVERIFIABLE_SIGNATURE;
1420         if (sb->s_user_ns != &init_user_ns)
1421                 sb->s_iflags |= SB_I_UNTRUSTED_MOUNTER;
1422         sb->s_flags &= ~(SB_NOSEC | SB_I_VERSION);
1423
1424         /*
1425          * If we are not in the initial user namespace posix
1426          * acls must be translated.
1427          */
1428         if (sb->s_user_ns != &init_user_ns)
1429                 sb->s_xattr = fuse_no_acl_xattr_handlers;
1430 }
1431
1432 static int fuse_fill_super_submount(struct super_block *sb,
1433                                     struct fuse_inode *parent_fi)
1434 {
1435         struct fuse_mount *fm = get_fuse_mount_super(sb);
1436         struct super_block *parent_sb = parent_fi->inode.i_sb;
1437         struct fuse_attr root_attr;
1438         struct inode *root;
1439
1440         fuse_sb_defaults(sb);
1441         fm->sb = sb;
1442
1443         WARN_ON(sb->s_bdi != &noop_backing_dev_info);
1444         sb->s_bdi = bdi_get(parent_sb->s_bdi);
1445
1446         sb->s_xattr = parent_sb->s_xattr;
1447         sb->s_time_gran = parent_sb->s_time_gran;
1448         sb->s_blocksize = parent_sb->s_blocksize;
1449         sb->s_blocksize_bits = parent_sb->s_blocksize_bits;
1450         sb->s_subtype = kstrdup(parent_sb->s_subtype, GFP_KERNEL);
1451         if (parent_sb->s_subtype && !sb->s_subtype)
1452                 return -ENOMEM;
1453
1454         fuse_fill_attr_from_inode(&root_attr, parent_fi);
1455         root = fuse_iget(sb, parent_fi->nodeid, 0, &root_attr, 0, 0);
1456         /*
1457          * This inode is just a duplicate, so it is not looked up and
1458          * its nlookup should not be incremented.  fuse_iget() does
1459          * that, though, so undo it here.
1460          */
1461         get_fuse_inode(root)->nlookup--;
1462         sb->s_d_op = &fuse_dentry_operations;
1463         sb->s_root = d_make_root(root);
1464         if (!sb->s_root)
1465                 return -ENOMEM;
1466
1467         return 0;
1468 }
1469
1470 /* Filesystem context private data holds the FUSE inode of the mount point */
1471 static int fuse_get_tree_submount(struct fs_context *fsc)
1472 {
1473         struct fuse_mount *fm;
1474         struct fuse_inode *mp_fi = fsc->fs_private;
1475         struct fuse_conn *fc = get_fuse_conn(&mp_fi->inode);
1476         struct super_block *sb;
1477         int err;
1478
1479         fm = kzalloc(sizeof(struct fuse_mount), GFP_KERNEL);
1480         if (!fm)
1481                 return -ENOMEM;
1482
1483         fm->fc = fuse_conn_get(fc);
1484         fsc->s_fs_info = fm;
1485         sb = sget_fc(fsc, NULL, set_anon_super_fc);
1486         if (fsc->s_fs_info)
1487                 fuse_mount_destroy(fm);
1488         if (IS_ERR(sb))
1489                 return PTR_ERR(sb);
1490
1491         /* Initialize superblock, making @mp_fi its root */
1492         err = fuse_fill_super_submount(sb, mp_fi);
1493         if (err) {
1494                 deactivate_locked_super(sb);
1495                 return err;
1496         }
1497
1498         down_write(&fc->killsb);
1499         list_add_tail(&fm->fc_entry, &fc->mounts);
1500         up_write(&fc->killsb);
1501
1502         sb->s_flags |= SB_ACTIVE;
1503         fsc->root = dget(sb->s_root);
1504
1505         return 0;
1506 }
1507
1508 static const struct fs_context_operations fuse_context_submount_ops = {
1509         .get_tree       = fuse_get_tree_submount,
1510 };
1511
1512 int fuse_init_fs_context_submount(struct fs_context *fsc)
1513 {
1514         fsc->ops = &fuse_context_submount_ops;
1515         return 0;
1516 }
1517 EXPORT_SYMBOL_GPL(fuse_init_fs_context_submount);
1518
1519 int fuse_fill_super_common(struct super_block *sb, struct fuse_fs_context *ctx)
1520 {
1521         struct fuse_dev *fud = NULL;
1522         struct fuse_mount *fm = get_fuse_mount_super(sb);
1523         struct fuse_conn *fc = fm->fc;
1524         struct inode *root;
1525         struct dentry *root_dentry;
1526         int err;
1527
1528         err = -EINVAL;
1529         if (sb->s_flags & SB_MANDLOCK)
1530                 goto err;
1531
1532         rcu_assign_pointer(fc->curr_bucket, fuse_sync_bucket_alloc());
1533         fuse_sb_defaults(sb);
1534
1535         if (ctx->is_bdev) {
1536 #ifdef CONFIG_BLOCK
1537                 err = -EINVAL;
1538                 if (!sb_set_blocksize(sb, ctx->blksize))
1539                         goto err;
1540 #endif
1541         } else {
1542                 sb->s_blocksize = PAGE_SIZE;
1543                 sb->s_blocksize_bits = PAGE_SHIFT;
1544         }
1545
1546         sb->s_subtype = ctx->subtype;
1547         ctx->subtype = NULL;
1548         if (IS_ENABLED(CONFIG_FUSE_DAX)) {
1549                 err = fuse_dax_conn_alloc(fc, ctx->dax_mode, ctx->dax_dev);
1550                 if (err)
1551                         goto err;
1552         }
1553
1554         if (ctx->fudptr) {
1555                 err = -ENOMEM;
1556                 fud = fuse_dev_alloc_install(fc);
1557                 if (!fud)
1558                         goto err_free_dax;
1559         }
1560
1561         fc->dev = sb->s_dev;
1562         fm->sb = sb;
1563         err = fuse_bdi_init(fc, sb);
1564         if (err)
1565                 goto err_dev_free;
1566
1567         /* Handle umasking inside the fuse code */
1568         if (sb->s_flags & SB_POSIXACL)
1569                 fc->dont_mask = 1;
1570         sb->s_flags |= SB_POSIXACL;
1571
1572         fc->default_permissions = ctx->default_permissions;
1573         fc->allow_other = ctx->allow_other;
1574         fc->user_id = ctx->user_id;
1575         fc->group_id = ctx->group_id;
1576         fc->legacy_opts_show = ctx->legacy_opts_show;
1577         fc->max_read = max_t(unsigned int, 4096, ctx->max_read);
1578         fc->destroy = ctx->destroy;
1579         fc->no_control = ctx->no_control;
1580         fc->no_force_umount = ctx->no_force_umount;
1581
1582         err = -ENOMEM;
1583         root = fuse_get_root_inode(sb, ctx->rootmode);
1584         sb->s_d_op = &fuse_root_dentry_operations;
1585         root_dentry = d_make_root(root);
1586         if (!root_dentry)
1587                 goto err_dev_free;
1588         /* Root dentry doesn't have .d_revalidate */
1589         sb->s_d_op = &fuse_dentry_operations;
1590
1591         mutex_lock(&fuse_mutex);
1592         err = -EINVAL;
1593         if (ctx->fudptr && *ctx->fudptr)
1594                 goto err_unlock;
1595
1596         err = fuse_ctl_add_conn(fc);
1597         if (err)
1598                 goto err_unlock;
1599
1600         list_add_tail(&fc->entry, &fuse_conn_list);
1601         sb->s_root = root_dentry;
1602         if (ctx->fudptr)
1603                 *ctx->fudptr = fud;
1604         mutex_unlock(&fuse_mutex);
1605         return 0;
1606
1607  err_unlock:
1608         mutex_unlock(&fuse_mutex);
1609         dput(root_dentry);
1610  err_dev_free:
1611         if (fud)
1612                 fuse_dev_free(fud);
1613  err_free_dax:
1614         if (IS_ENABLED(CONFIG_FUSE_DAX))
1615                 fuse_dax_conn_free(fc);
1616  err:
1617         return err;
1618 }
1619 EXPORT_SYMBOL_GPL(fuse_fill_super_common);
1620
1621 static int fuse_fill_super(struct super_block *sb, struct fs_context *fsc)
1622 {
1623         struct fuse_fs_context *ctx = fsc->fs_private;
1624         int err;
1625
1626         if (!ctx->file || !ctx->rootmode_present ||
1627             !ctx->user_id_present || !ctx->group_id_present)
1628                 return -EINVAL;
1629
1630         /*
1631          * Require mount to happen from the same user namespace which
1632          * opened /dev/fuse to prevent potential attacks.
1633          */
1634         if ((ctx->file->f_op != &fuse_dev_operations) ||
1635             (ctx->file->f_cred->user_ns != sb->s_user_ns))
1636                 return -EINVAL;
1637         ctx->fudptr = &ctx->file->private_data;
1638
1639         err = fuse_fill_super_common(sb, ctx);
1640         if (err)
1641                 return err;
1642         /* file->private_data shall be visible on all CPUs after this */
1643         smp_mb();
1644         fuse_send_init(get_fuse_mount_super(sb));
1645         return 0;
1646 }
1647
1648 /*
1649  * This is the path where user supplied an already initialized fuse dev.  In
1650  * this case never create a new super if the old one is gone.
1651  */
1652 static int fuse_set_no_super(struct super_block *sb, struct fs_context *fsc)
1653 {
1654         return -ENOTCONN;
1655 }
1656
1657 static int fuse_test_super(struct super_block *sb, struct fs_context *fsc)
1658 {
1659
1660         return fsc->sget_key == get_fuse_conn_super(sb);
1661 }
1662
1663 static int fuse_get_tree(struct fs_context *fsc)
1664 {
1665         struct fuse_fs_context *ctx = fsc->fs_private;
1666         struct fuse_dev *fud;
1667         struct fuse_conn *fc;
1668         struct fuse_mount *fm;
1669         struct super_block *sb;
1670         int err;
1671
1672         fc = kmalloc(sizeof(*fc), GFP_KERNEL);
1673         if (!fc)
1674                 return -ENOMEM;
1675
1676         fm = kzalloc(sizeof(*fm), GFP_KERNEL);
1677         if (!fm) {
1678                 kfree(fc);
1679                 return -ENOMEM;
1680         }
1681
1682         fuse_conn_init(fc, fm, fsc->user_ns, &fuse_dev_fiq_ops, NULL);
1683         fc->release = fuse_free_conn;
1684
1685         fsc->s_fs_info = fm;
1686
1687         if (ctx->fd_present)
1688                 ctx->file = fget(ctx->fd);
1689
1690         if (IS_ENABLED(CONFIG_BLOCK) && ctx->is_bdev) {
1691                 err = get_tree_bdev(fsc, fuse_fill_super);
1692                 goto out;
1693         }
1694         /*
1695          * While block dev mount can be initialized with a dummy device fd
1696          * (found by device name), normal fuse mounts can't
1697          */
1698         err = -EINVAL;
1699         if (!ctx->file)
1700                 goto out;
1701
1702         /*
1703          * Allow creating a fuse mount with an already initialized fuse
1704          * connection
1705          */
1706         fud = READ_ONCE(ctx->file->private_data);
1707         if (ctx->file->f_op == &fuse_dev_operations && fud) {
1708                 fsc->sget_key = fud->fc;
1709                 sb = sget_fc(fsc, fuse_test_super, fuse_set_no_super);
1710                 err = PTR_ERR_OR_ZERO(sb);
1711                 if (!IS_ERR(sb))
1712                         fsc->root = dget(sb->s_root);
1713         } else {
1714                 err = get_tree_nodev(fsc, fuse_fill_super);
1715         }
1716 out:
1717         if (fsc->s_fs_info)
1718                 fuse_mount_destroy(fm);
1719         if (ctx->file)
1720                 fput(ctx->file);
1721         return err;
1722 }
1723
1724 static const struct fs_context_operations fuse_context_ops = {
1725         .free           = fuse_free_fsc,
1726         .parse_param    = fuse_parse_param,
1727         .reconfigure    = fuse_reconfigure,
1728         .get_tree       = fuse_get_tree,
1729 };
1730
1731 /*
1732  * Set up the filesystem mount context.
1733  */
1734 static int fuse_init_fs_context(struct fs_context *fsc)
1735 {
1736         struct fuse_fs_context *ctx;
1737
1738         ctx = kzalloc(sizeof(struct fuse_fs_context), GFP_KERNEL);
1739         if (!ctx)
1740                 return -ENOMEM;
1741
1742         ctx->max_read = ~0;
1743         ctx->blksize = FUSE_DEFAULT_BLKSIZE;
1744         ctx->legacy_opts_show = true;
1745
1746 #ifdef CONFIG_BLOCK
1747         if (fsc->fs_type == &fuseblk_fs_type) {
1748                 ctx->is_bdev = true;
1749                 ctx->destroy = true;
1750         }
1751 #endif
1752
1753         fsc->fs_private = ctx;
1754         fsc->ops = &fuse_context_ops;
1755         return 0;
1756 }
1757
1758 bool fuse_mount_remove(struct fuse_mount *fm)
1759 {
1760         struct fuse_conn *fc = fm->fc;
1761         bool last = false;
1762
1763         down_write(&fc->killsb);
1764         list_del_init(&fm->fc_entry);
1765         if (list_empty(&fc->mounts))
1766                 last = true;
1767         up_write(&fc->killsb);
1768
1769         return last;
1770 }
1771 EXPORT_SYMBOL_GPL(fuse_mount_remove);
1772
1773 void fuse_conn_destroy(struct fuse_mount *fm)
1774 {
1775         struct fuse_conn *fc = fm->fc;
1776
1777         if (fc->destroy)
1778                 fuse_send_destroy(fm);
1779
1780         fuse_abort_conn(fc);
1781         fuse_wait_aborted(fc);
1782
1783         if (!list_empty(&fc->entry)) {
1784                 mutex_lock(&fuse_mutex);
1785                 list_del(&fc->entry);
1786                 fuse_ctl_remove_conn(fc);
1787                 mutex_unlock(&fuse_mutex);
1788         }
1789 }
1790 EXPORT_SYMBOL_GPL(fuse_conn_destroy);
1791
1792 static void fuse_sb_destroy(struct super_block *sb)
1793 {
1794         struct fuse_mount *fm = get_fuse_mount_super(sb);
1795         bool last;
1796
1797         if (sb->s_root) {
1798                 last = fuse_mount_remove(fm);
1799                 if (last)
1800                         fuse_conn_destroy(fm);
1801         }
1802 }
1803
1804 void fuse_mount_destroy(struct fuse_mount *fm)
1805 {
1806         fuse_conn_put(fm->fc);
1807         kfree(fm);
1808 }
1809 EXPORT_SYMBOL(fuse_mount_destroy);
1810
1811 static void fuse_kill_sb_anon(struct super_block *sb)
1812 {
1813         fuse_sb_destroy(sb);
1814         kill_anon_super(sb);
1815         fuse_mount_destroy(get_fuse_mount_super(sb));
1816 }
1817
1818 static struct file_system_type fuse_fs_type = {
1819         .owner          = THIS_MODULE,
1820         .name           = "fuse",
1821         .fs_flags       = FS_HAS_SUBTYPE | FS_USERNS_MOUNT,
1822         .init_fs_context = fuse_init_fs_context,
1823         .parameters     = fuse_fs_parameters,
1824         .kill_sb        = fuse_kill_sb_anon,
1825 };
1826 MODULE_ALIAS_FS("fuse");
1827
1828 #ifdef CONFIG_BLOCK
1829 static void fuse_kill_sb_blk(struct super_block *sb)
1830 {
1831         fuse_sb_destroy(sb);
1832         kill_block_super(sb);
1833         fuse_mount_destroy(get_fuse_mount_super(sb));
1834 }
1835
1836 static struct file_system_type fuseblk_fs_type = {
1837         .owner          = THIS_MODULE,
1838         .name           = "fuseblk",
1839         .init_fs_context = fuse_init_fs_context,
1840         .parameters     = fuse_fs_parameters,
1841         .kill_sb        = fuse_kill_sb_blk,
1842         .fs_flags       = FS_REQUIRES_DEV | FS_HAS_SUBTYPE,
1843 };
1844 MODULE_ALIAS_FS("fuseblk");
1845
1846 static inline int register_fuseblk(void)
1847 {
1848         return register_filesystem(&fuseblk_fs_type);
1849 }
1850
1851 static inline void unregister_fuseblk(void)
1852 {
1853         unregister_filesystem(&fuseblk_fs_type);
1854 }
1855 #else
1856 static inline int register_fuseblk(void)
1857 {
1858         return 0;
1859 }
1860
1861 static inline void unregister_fuseblk(void)
1862 {
1863 }
1864 #endif
1865
1866 static void fuse_inode_init_once(void *foo)
1867 {
1868         struct inode *inode = foo;
1869
1870         inode_init_once(inode);
1871 }
1872
1873 static int __init fuse_fs_init(void)
1874 {
1875         int err;
1876
1877         fuse_inode_cachep = kmem_cache_create("fuse_inode",
1878                         sizeof(struct fuse_inode), 0,
1879                         SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT|SLAB_RECLAIM_ACCOUNT,
1880                         fuse_inode_init_once);
1881         err = -ENOMEM;
1882         if (!fuse_inode_cachep)
1883                 goto out;
1884
1885         err = register_fuseblk();
1886         if (err)
1887                 goto out2;
1888
1889         err = register_filesystem(&fuse_fs_type);
1890         if (err)
1891                 goto out3;
1892
1893         return 0;
1894
1895  out3:
1896         unregister_fuseblk();
1897  out2:
1898         kmem_cache_destroy(fuse_inode_cachep);
1899  out:
1900         return err;
1901 }
1902
1903 static void fuse_fs_cleanup(void)
1904 {
1905         unregister_filesystem(&fuse_fs_type);
1906         unregister_fuseblk();
1907
1908         /*
1909          * Make sure all delayed rcu free inodes are flushed before we
1910          * destroy cache.
1911          */
1912         rcu_barrier();
1913         kmem_cache_destroy(fuse_inode_cachep);
1914 }
1915
1916 static struct kobject *fuse_kobj;
1917
1918 static int fuse_sysfs_init(void)
1919 {
1920         int err;
1921
1922         fuse_kobj = kobject_create_and_add("fuse", fs_kobj);
1923         if (!fuse_kobj) {
1924                 err = -ENOMEM;
1925                 goto out_err;
1926         }
1927
1928         err = sysfs_create_mount_point(fuse_kobj, "connections");
1929         if (err)
1930                 goto out_fuse_unregister;
1931
1932         return 0;
1933
1934  out_fuse_unregister:
1935         kobject_put(fuse_kobj);
1936  out_err:
1937         return err;
1938 }
1939
1940 static void fuse_sysfs_cleanup(void)
1941 {
1942         sysfs_remove_mount_point(fuse_kobj, "connections");
1943         kobject_put(fuse_kobj);
1944 }
1945
1946 static int __init fuse_init(void)
1947 {
1948         int res;
1949
1950         pr_info("init (API version %i.%i)\n",
1951                 FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);
1952
1953         INIT_LIST_HEAD(&fuse_conn_list);
1954         res = fuse_fs_init();
1955         if (res)
1956                 goto err;
1957
1958         res = fuse_dev_init();
1959         if (res)
1960                 goto err_fs_cleanup;
1961
1962         res = fuse_sysfs_init();
1963         if (res)
1964                 goto err_dev_cleanup;
1965
1966         res = fuse_ctl_init();
1967         if (res)
1968                 goto err_sysfs_cleanup;
1969
1970         sanitize_global_limit(&max_user_bgreq);
1971         sanitize_global_limit(&max_user_congthresh);
1972
1973         return 0;
1974
1975  err_sysfs_cleanup:
1976         fuse_sysfs_cleanup();
1977  err_dev_cleanup:
1978         fuse_dev_cleanup();
1979  err_fs_cleanup:
1980         fuse_fs_cleanup();
1981  err:
1982         return res;
1983 }
1984
1985 static void __exit fuse_exit(void)
1986 {
1987         pr_debug("exit\n");
1988
1989         fuse_ctl_cleanup();
1990         fuse_sysfs_cleanup();
1991         fuse_fs_cleanup();
1992         fuse_dev_cleanup();
1993 }
1994
1995 module_init(fuse_init);
1996 module_exit(fuse_exit);