fs/fuse/inode.c

   1 /*
   2   FUSE: Filesystem in Userspace
   3   Copyright (C) 2001-2008  Miklos Szeredi <miklos@szeredi.hu>
   4
   5   This program can be distributed under the terms of the GNU GPL.
   6   See the file COPYING.
   7 */
   8
   9 #include "fuse_i.h"
  10
  11 #include <linux/pagemap.h>
  12 #include <linux/slab.h>
  13 #include <linux/file.h>
  14 #include <linux/seq_file.h>
  15 #include <linux/init.h>
  16 #include <linux/module.h>
  17 #include <linux/moduleparam.h>
  18 #include <linux/parser.h>
  19 #include <linux/statfs.h>
  20 #include <linux/random.h>
  21 #include <linux/sched.h>
  22 #include <linux/exportfs.h>
  23 #include <linux/posix_acl.h>
  24 #include <linux/pid_namespace.h>
  25
  26 MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
  27 MODULE_DESCRIPTION("Filesystem in Userspace");
  28 MODULE_LICENSE("GPL");
  29
  30 static struct kmem_cache *fuse_inode_cachep;
  31 struct list_head fuse_conn_list;
  32 DEFINE_MUTEX(fuse_mutex);
  33
  34 static int set_global_limit(const char *val, const struct kernel_param *kp);
  35
  36 unsigned max_user_bgreq;
  37 module_param_call(max_user_bgreq, set_global_limit, param_get_uint,
  38                   &max_user_bgreq, 0644);
  39 __MODULE_PARM_TYPE(max_user_bgreq, "uint");
  40 MODULE_PARM_DESC(max_user_bgreq,
  41  "Global limit for the maximum number of backgrounded requests an "
  42  "unprivileged user can set");
  43
  44 unsigned max_user_congthresh;
  45 module_param_call(max_user_congthresh, set_global_limit, param_get_uint,
  46                   &max_user_congthresh, 0644);
  47 __MODULE_PARM_TYPE(max_user_congthresh, "uint");
  48 MODULE_PARM_DESC(max_user_congthresh,
  49  "Global limit for the maximum congestion threshold an "
  50  "unprivileged user can set");
  51
  52 #define FUSE_SUPER_MAGIC 0x65735546
  53
  54 #define FUSE_DEFAULT_BLKSIZE 512
  55
  56 /** Maximum number of outstanding background requests */
  57 #define FUSE_DEFAULT_MAX_BACKGROUND 12
  58
  59 /** Congestion starts at 75% of maximum */
  60 #define FUSE_DEFAULT_CONGESTION_THRESHOLD (FUSE_DEFAULT_MAX_BACKGROUND * 3 / 4)
  61
  62 struct fuse_mount_data {
  63         int fd;
  64         unsigned rootmode;
  65         kuid_t user_id;
  66         kgid_t group_id;
  67         unsigned fd_present:1;
  68         unsigned rootmode_present:1;
  69         unsigned user_id_present:1;
  70         unsigned group_id_present:1;
  71         unsigned default_permissions:1;
  72         unsigned allow_other:1;
  73         unsigned max_read;
  74         unsigned blksize;
  75 };
  76
  77 struct fuse_forget_link *fuse_alloc_forget(void)
  78 {
  79         return kzalloc(sizeof(struct fuse_forget_link), GFP_KERNEL);
  80 }
  81
  82 static struct inode *fuse_alloc_inode(struct super_block *sb)
  83 {
  84         struct fuse_inode *fi;
  85
  86         fi = kmem_cache_alloc(fuse_inode_cachep, GFP_KERNEL);
  87         if (!fi)
  88                 return NULL;
  89
  90         fi->i_time = 0;
  91         fi->inval_mask = 0;
  92         fi->nodeid = 0;
  93         fi->nlookup = 0;
  94         fi->attr_version = 0;
  95         fi->orig_ino = 0;
  96         fi->state = 0;
  97         mutex_init(&fi->mutex);
  98         spin_lock_init(&fi->lock);
  99         fi->forget = fuse_alloc_forget();
 100         if (!fi->forget) {
 101                 kmem_cache_free(fuse_inode_cachep, fi);
 102                 return NULL;
 103         }
 104
 105         return &fi->inode;
 106 }
 107
 108 static void fuse_i_callback(struct rcu_head *head)
 109 {
 110         struct inode *inode = container_of(head, struct inode, i_rcu);
 111         kmem_cache_free(fuse_inode_cachep, inode);
 112 }
 113
 114 static void fuse_destroy_inode(struct inode *inode)
 115 {
 116         struct fuse_inode *fi = get_fuse_inode(inode);
 117         if (S_ISREG(inode->i_mode) && !is_bad_inode(inode)) {
 118                 WARN_ON(!list_empty(&fi->write_files));
 119                 WARN_ON(!list_empty(&fi->queued_writes));
 120         }
 121         mutex_destroy(&fi->mutex);
 122         kfree(fi->forget);
 123         call_rcu(&inode->i_rcu, fuse_i_callback);
 124 }
 125
 126 static void fuse_evict_inode(struct inode *inode)
 127 {
 128         truncate_inode_pages_final(&inode->i_data);
 129         clear_inode(inode);
 130         if (inode->i_sb->s_flags & SB_ACTIVE) {
 131                 struct fuse_conn *fc = get_fuse_conn(inode);
 132                 struct fuse_inode *fi = get_fuse_inode(inode);
 133                 fuse_queue_forget(fc, fi->forget, fi->nodeid, fi->nlookup);
 134                 fi->forget = NULL;
 135         }
 136 }
 137
 138 static int fuse_remount_fs(struct super_block *sb, int *flags, char *data)
 139 {
 140         sync_filesystem(sb);
 141         if (*flags & SB_MANDLOCK)
 142                 return -EINVAL;
 143
 144         return 0;
 145 }
 146
 147 /*
 148  * ino_t is 32-bits on 32-bit arch. We have to squash the 64-bit value down
 149  * so that it will fit.
 150  */
 151 static ino_t fuse_squash_ino(u64 ino64)
 152 {
 153         ino_t ino = (ino_t) ino64;
 154         if (sizeof(ino_t) < sizeof(u64))
 155                 ino ^= ino64 >> (sizeof(u64) - sizeof(ino_t)) * 8;
 156         return ino;
 157 }
 158
 159 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
 160                                    u64 attr_valid)
 161 {
 162         struct fuse_conn *fc = get_fuse_conn(inode);
 163         struct fuse_inode *fi = get_fuse_inode(inode);
 164
 165         lockdep_assert_held(&fi->lock);
 166
 167         fi->attr_version = atomic64_inc_return(&fc->attr_version);
 168         fi->i_time = attr_valid;
 169         WRITE_ONCE(fi->inval_mask, 0);
 170
 171         inode->i_ino     = fuse_squash_ino(attr->ino);
 172         inode->i_mode    = (inode->i_mode & S_IFMT) | (attr->mode & 07777);
 173         set_nlink(inode, attr->nlink);
 174         inode->i_uid     = make_kuid(fc->user_ns, attr->uid);
 175         inode->i_gid     = make_kgid(fc->user_ns, attr->gid);
 176         inode->i_blocks  = attr->blocks;
 177         inode->i_atime.tv_sec   = attr->atime;
 178         inode->i_atime.tv_nsec  = attr->atimensec;
 179         /* mtime from server may be stale due to local buffered write */
 180         if (!fc->writeback_cache || !S_ISREG(inode->i_mode)) {
 181                 inode->i_mtime.tv_sec   = attr->mtime;
 182                 inode->i_mtime.tv_nsec  = attr->mtimensec;
 183                 inode->i_ctime.tv_sec   = attr->ctime;
 184                 inode->i_ctime.tv_nsec  = attr->ctimensec;
 185         }
 186
 187         if (attr->blksize != 0)
 188                 inode->i_blkbits = ilog2(attr->blksize);
 189         else
 190                 inode->i_blkbits = inode->i_sb->s_blocksize_bits;
 191
 192         /*
 193          * Don't set the sticky bit in i_mode, unless we want the VFS
 194          * to check permissions.  This prevents failures due to the
 195          * check in may_delete().
 196          */
 197         fi->orig_i_mode = inode->i_mode;
 198         if (!fc->default_permissions)
 199                 inode->i_mode &= ~S_ISVTX;
 200
 201         fi->orig_ino = attr->ino;
 202 }
 203
 204 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
 205                             u64 attr_valid, u64 attr_version)
 206 {
 207         struct fuse_conn *fc = get_fuse_conn(inode);
 208         struct fuse_inode *fi = get_fuse_inode(inode);
 209         bool is_wb = fc->writeback_cache;
 210         loff_t oldsize;
 211         struct timespec64 old_mtime;
 212
 213         spin_lock(&fi->lock);
 214         if ((attr_version != 0 && fi->attr_version > attr_version) ||
 215             test_bit(FUSE_I_SIZE_UNSTABLE, &fi->state)) {
 216                 spin_unlock(&fi->lock);
 217                 return;
 218         }
 219
 220         old_mtime = inode->i_mtime;
 221         fuse_change_attributes_common(inode, attr, attr_valid);
 222
 223         oldsize = inode->i_size;
 224         /*
 225          * In case of writeback_cache enabled, the cached writes beyond EOF
 226          * extend local i_size without keeping userspace server in sync. So,
 227          * attr->size coming from server can be stale. We cannot trust it.
 228          */
 229         if (!is_wb || !S_ISREG(inode->i_mode))
 230                 i_size_write(inode, attr->size);
 231         spin_unlock(&fi->lock);
 232
 233         if (!is_wb && S_ISREG(inode->i_mode)) {
 234                 bool inval = false;
 235
 236                 if (oldsize != attr->size) {
 237                         truncate_pagecache(inode, attr->size);
 238                         if (!fc->explicit_inval_data)
 239                                 inval = true;
 240                 } else if (fc->auto_inval_data) {
 241                         struct timespec64 new_mtime = {
 242                                 .tv_sec = attr->mtime,
 243                                 .tv_nsec = attr->mtimensec,
 244                         };
 245
 246                         /*
 247                          * Auto inval mode also checks and invalidates if mtime
 248                          * has changed.
 249                          */
 250                         if (!timespec64_equal(&old_mtime, &new_mtime))
 251                                 inval = true;
 252                 }
 253
 254                 if (inval)
 255                         invalidate_inode_pages2(inode->i_mapping);
 256         }
 257 }
 258
 259 static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr)
 260 {
 261         inode->i_mode = attr->mode & S_IFMT;
 262         inode->i_size = attr->size;
 263         inode->i_mtime.tv_sec  = attr->mtime;
 264         inode->i_mtime.tv_nsec = attr->mtimensec;
 265         inode->i_ctime.tv_sec  = attr->ctime;
 266         inode->i_ctime.tv_nsec = attr->ctimensec;
 267         if (S_ISREG(inode->i_mode)) {
 268                 fuse_init_common(inode);
 269                 fuse_init_file_inode(inode);
 270         } else if (S_ISDIR(inode->i_mode))
 271                 fuse_init_dir(inode);
 272         else if (S_ISLNK(inode->i_mode))
 273                 fuse_init_symlink(inode);
 274         else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
 275                  S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
 276                 fuse_init_common(inode);
 277                 init_special_inode(inode, inode->i_mode,
 278                                    new_decode_dev(attr->rdev));
 279         } else
 280                 BUG();
 281 }
 282
 283 int fuse_inode_eq(struct inode *inode, void *_nodeidp)
 284 {
 285         u64 nodeid = *(u64 *) _nodeidp;
 286         if (get_node_id(inode) == nodeid)
 287                 return 1;
 288         else
 289                 return 0;
 290 }
 291
 292 static int fuse_inode_set(struct inode *inode, void *_nodeidp)
 293 {
 294         u64 nodeid = *(u64 *) _nodeidp;
 295         get_fuse_inode(inode)->nodeid = nodeid;
 296         return 0;
 297 }
 298
 299 struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
 300                         int generation, struct fuse_attr *attr,
 301                         u64 attr_valid, u64 attr_version)
 302 {
 303         struct inode *inode;
 304         struct fuse_inode *fi;
 305         struct fuse_conn *fc = get_fuse_conn_super(sb);
 306
 307  retry:
 308         inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid);
 309         if (!inode)
 310                 return NULL;
 311
 312         if ((inode->i_state & I_NEW)) {
 313                 inode->i_flags |= S_NOATIME;
 314                 if (!fc->writeback_cache || !S_ISREG(attr->mode))
 315                         inode->i_flags |= S_NOCMTIME;
 316                 inode->i_generation = generation;
 317                 fuse_init_inode(inode, attr);
 318                 unlock_new_inode(inode);
 319         } else if ((inode->i_mode ^ attr->mode) & S_IFMT) {
 320                 /* Inode has changed type, any I/O on the old should fail */
 321                 make_bad_inode(inode);
 322                 iput(inode);
 323                 goto retry;
 324         }
 325
 326         fi = get_fuse_inode(inode);
 327         spin_lock(&fi->lock);
 328         fi->nlookup++;
 329         spin_unlock(&fi->lock);
 330         fuse_change_attributes(inode, attr, attr_valid, attr_version);
 331
 332         return inode;
 333 }
 334
 335 int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid,
 336                              loff_t offset, loff_t len)
 337 {
 338         struct inode *inode;
 339         pgoff_t pg_start;
 340         pgoff_t pg_end;
 341
 342         inode = ilookup5(sb, nodeid, fuse_inode_eq, &nodeid);
 343         if (!inode)
 344                 return -ENOENT;
 345
 346         fuse_invalidate_attr(inode);
 347         forget_all_cached_acls(inode);
 348         if (offset >= 0) {
 349                 pg_start = offset >> PAGE_SHIFT;
 350                 if (len <= 0)
 351                         pg_end = -1;
 352                 else
 353                         pg_end = (offset + len - 1) >> PAGE_SHIFT;
 354                 invalidate_inode_pages2_range(inode->i_mapping,
 355                                               pg_start, pg_end);
 356         }
 357         iput(inode);
 358         return 0;
 359 }
 360
 361 bool fuse_lock_inode(struct inode *inode)
 362 {
 363         bool locked = false;
 364
 365         if (!get_fuse_conn(inode)->parallel_dirops) {
 366                 mutex_lock(&get_fuse_inode(inode)->mutex);
 367                 locked = true;
 368         }
 369
 370         return locked;
 371 }
 372
 373 void fuse_unlock_inode(struct inode *inode, bool locked)
 374 {
 375         if (locked)
 376                 mutex_unlock(&get_fuse_inode(inode)->mutex);
 377 }
 378
 379 static void fuse_umount_begin(struct super_block *sb)
 380 {
 381         fuse_abort_conn(get_fuse_conn_super(sb));
 382 }
 383
 384 static void fuse_send_destroy(struct fuse_conn *fc)
 385 {
 386         struct fuse_req *req = fc->destroy_req;
 387         if (req && fc->conn_init) {
 388                 fc->destroy_req = NULL;
 389                 req->in.h.opcode = FUSE_DESTROY;
 390                 __set_bit(FR_FORCE, &req->flags);
 391                 __clear_bit(FR_BACKGROUND, &req->flags);
 392                 fuse_request_send(fc, req);
 393                 fuse_put_request(fc, req);
 394         }
 395 }
 396
 397 static void fuse_put_super(struct super_block *sb)
 398 {
 399         struct fuse_conn *fc = get_fuse_conn_super(sb);
 400
 401         mutex_lock(&fuse_mutex);
 402         list_del(&fc->entry);
 403         fuse_ctl_remove_conn(fc);
 404         mutex_unlock(&fuse_mutex);
 405
 406         fuse_conn_put(fc);
 407 }
 408
 409 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr)
 410 {
 411         stbuf->f_type    = FUSE_SUPER_MAGIC;
 412         stbuf->f_bsize   = attr->bsize;
 413         stbuf->f_frsize  = attr->frsize;
 414         stbuf->f_blocks  = attr->blocks;
 415         stbuf->f_bfree   = attr->bfree;
 416         stbuf->f_bavail  = attr->bavail;
 417         stbuf->f_files   = attr->files;
 418         stbuf->f_ffree   = attr->ffree;
 419         stbuf->f_namelen = attr->namelen;
 420         /* fsid is left zero */
 421 }
 422
 423 static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf)
 424 {
 425         struct super_block *sb = dentry->d_sb;
 426         struct fuse_conn *fc = get_fuse_conn_super(sb);
 427         FUSE_ARGS(args);
 428         struct fuse_statfs_out outarg;
 429         int err;
 430
 431         if (!fuse_allow_current_process(fc)) {
 432                 buf->f_type = FUSE_SUPER_MAGIC;
 433                 return 0;
 434         }
 435
 436         memset(&outarg, 0, sizeof(outarg));
 437         args.in.numargs = 0;
 438         args.in.h.opcode = FUSE_STATFS;
 439         args.in.h.nodeid = get_node_id(d_inode(dentry));
 440         args.out.numargs = 1;
 441         args.out.args[0].size = sizeof(outarg);
 442         args.out.args[0].value = &outarg;
 443         err = fuse_simple_request(fc, &args);
 444         if (!err)
 445                 convert_fuse_statfs(buf, &outarg.st);
 446         return err;
 447 }
 448
 449 enum {
 450         OPT_FD,
 451         OPT_ROOTMODE,
 452         OPT_USER_ID,
 453         OPT_GROUP_ID,
 454         OPT_DEFAULT_PERMISSIONS,
 455         OPT_ALLOW_OTHER,
 456         OPT_MAX_READ,
 457         OPT_BLKSIZE,
 458         OPT_ERR
 459 };
 460
 461 static const match_table_t tokens = {
 462         {OPT_FD,                        "fd=%u"},
 463         {OPT_ROOTMODE,                  "rootmode=%o"},
 464         {OPT_USER_ID,                   "user_id=%u"},
 465         {OPT_GROUP_ID,                  "group_id=%u"},
 466         {OPT_DEFAULT_PERMISSIONS,       "default_permissions"},
 467         {OPT_ALLOW_OTHER,               "allow_other"},
 468         {OPT_MAX_READ,                  "max_read=%u"},
 469         {OPT_BLKSIZE,                   "blksize=%u"},
 470         {OPT_ERR,                       NULL}
 471 };
 472
 473 static int fuse_match_uint(substring_t *s, unsigned int *res)
 474 {
 475         int err = -ENOMEM;
 476         char *buf = match_strdup(s);
 477         if (buf) {
 478                 err = kstrtouint(buf, 10, res);
 479                 kfree(buf);
 480         }
 481         return err;
 482 }
 483
 484 static int parse_fuse_opt(char *opt, struct fuse_mount_data *d, int is_bdev,
 485                           struct user_namespace *user_ns)
 486 {
 487         char *p;
 488         memset(d, 0, sizeof(struct fuse_mount_data));
 489         d->max_read = ~0;
 490         d->blksize = FUSE_DEFAULT_BLKSIZE;
 491
 492         while ((p = strsep(&opt, ",")) != NULL) {
 493                 int token;
 494                 int value;
 495                 unsigned uv;
 496                 substring_t args[MAX_OPT_ARGS];
 497                 if (!*p)
 498                         continue;
 499
 500                 token = match_token(p, tokens, args);
 501                 switch (token) {
 502                 case OPT_FD:
 503                         if (match_int(&args[0], &value))
 504                                 return 0;
 505                         d->fd = value;
 506                         d->fd_present = 1;
 507                         break;
 508
 509                 case OPT_ROOTMODE:
 510                         if (match_octal(&args[0], &value))
 511                                 return 0;
 512                         if (!fuse_valid_type(value))
 513                                 return 0;
 514                         d->rootmode = value;
 515                         d->rootmode_present = 1;
 516                         break;
 517
 518                 case OPT_USER_ID:
 519                         if (fuse_match_uint(&args[0], &uv))
 520                                 return 0;
 521                         d->user_id = make_kuid(user_ns, uv);
 522                         if (!uid_valid(d->user_id))
 523                                 return 0;
 524                         d->user_id_present = 1;
 525                         break;
 526
 527                 case OPT_GROUP_ID:
 528                         if (fuse_match_uint(&args[0], &uv))
 529                                 return 0;
 530                         d->group_id = make_kgid(user_ns, uv);
 531                         if (!gid_valid(d->group_id))
 532                                 return 0;
 533                         d->group_id_present = 1;
 534                         break;
 535
 536                 case OPT_DEFAULT_PERMISSIONS:
 537                         d->default_permissions = 1;
 538                         break;
 539
 540                 case OPT_ALLOW_OTHER:
 541                         d->allow_other = 1;
 542                         break;
 543
 544                 case OPT_MAX_READ:
 545                         if (match_int(&args[0], &value))
 546                                 return 0;
 547                         d->max_read = value;
 548                         break;
 549
 550                 case OPT_BLKSIZE:
 551                         if (!is_bdev || match_int(&args[0], &value))
 552                                 return 0;
 553                         d->blksize = value;
 554                         break;
 555
 556                 default:
 557                         return 0;
 558                 }
 559         }
 560
 561         if (!d->fd_present || !d->rootmode_present ||
 562             !d->user_id_present || !d->group_id_present)
 563                 return 0;
 564
 565         return 1;
 566 }
 567
 568 static int fuse_show_options(struct seq_file *m, struct dentry *root)
 569 {
 570         struct super_block *sb = root->d_sb;
 571         struct fuse_conn *fc = get_fuse_conn_super(sb);
 572
 573         seq_printf(m, ",user_id=%u", from_kuid_munged(fc->user_ns, fc->user_id));
 574         seq_printf(m, ",group_id=%u", from_kgid_munged(fc->user_ns, fc->group_id));
 575         if (fc->default_permissions)
 576                 seq_puts(m, ",default_permissions");
 577         if (fc->allow_other)
 578                 seq_puts(m, ",allow_other");
 579         if (fc->max_read != ~0)
 580                 seq_printf(m, ",max_read=%u", fc->max_read);
 581         if (sb->s_bdev && sb->s_blocksize != FUSE_DEFAULT_BLKSIZE)
 582                 seq_printf(m, ",blksize=%lu", sb->s_blocksize);
 583         return 0;
 584 }
 585
 586 static void fuse_iqueue_init(struct fuse_iqueue *fiq)
 587 {
 588         memset(fiq, 0, sizeof(struct fuse_iqueue));
 589         init_waitqueue_head(&fiq->waitq);
 590         INIT_LIST_HEAD(&fiq->pending);
 591         INIT_LIST_HEAD(&fiq->interrupts);
 592         fiq->forget_list_tail = &fiq->forget_list_head;
 593         fiq->connected = 1;
 594 }
 595
 596 static void fuse_pqueue_init(struct fuse_pqueue *fpq)
 597 {
 598         unsigned int i;
 599
 600         spin_lock_init(&fpq->lock);
 601         for (i = 0; i < FUSE_PQ_HASH_SIZE; i++)
 602                 INIT_LIST_HEAD(&fpq->processing[i]);
 603         INIT_LIST_HEAD(&fpq->io);
 604         fpq->connected = 1;
 605 }
 606
 607 void fuse_conn_init(struct fuse_conn *fc, struct user_namespace *user_ns)
 608 {
 609         memset(fc, 0, sizeof(*fc));
 610         spin_lock_init(&fc->lock);
 611         spin_lock_init(&fc->bg_lock);
 612         init_rwsem(&fc->killsb);
 613         refcount_set(&fc->count, 1);
 614         atomic_set(&fc->dev_count, 1);
 615         init_waitqueue_head(&fc->blocked_waitq);
 616         init_waitqueue_head(&fc->reserved_req_waitq);
 617         fuse_iqueue_init(&fc->iq);
 618         INIT_LIST_HEAD(&fc->bg_queue);
 619         INIT_LIST_HEAD(&fc->entry);
 620         INIT_LIST_HEAD(&fc->devices);
 621         atomic_set(&fc->num_waiting, 0);
 622         fc->max_background = FUSE_DEFAULT_MAX_BACKGROUND;
 623         fc->congestion_threshold = FUSE_DEFAULT_CONGESTION_THRESHOLD;
 624         atomic64_set(&fc->khctr, 0);
 625         fc->polled_files = RB_ROOT;
 626         fc->blocked = 0;
 627         fc->initialized = 0;
 628         fc->connected = 1;
 629         atomic64_set(&fc->attr_version, 1);
 630         get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key));
 631         fc->pid_ns = get_pid_ns(task_active_pid_ns(current));
 632         fc->user_ns = get_user_ns(user_ns);
 633         fc->max_pages = FUSE_DEFAULT_MAX_PAGES_PER_REQ;
 634 }
 635 EXPORT_SYMBOL_GPL(fuse_conn_init);
 636
 637 void fuse_conn_put(struct fuse_conn *fc)
 638 {
 639         if (refcount_dec_and_test(&fc->count)) {
 640                 if (fc->destroy_req)
 641                         fuse_request_free(fc->destroy_req);
 642                 put_pid_ns(fc->pid_ns);
 643                 put_user_ns(fc->user_ns);
 644                 fc->release(fc);
 645         }
 646 }
 647 EXPORT_SYMBOL_GPL(fuse_conn_put);
 648
 649 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc)
 650 {
 651         refcount_inc(&fc->count);
 652         return fc;
 653 }
 654 EXPORT_SYMBOL_GPL(fuse_conn_get);
 655
 656 static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned mode)
 657 {
 658         struct fuse_attr attr;
 659         memset(&attr, 0, sizeof(attr));
 660
 661         attr.mode = mode;
 662         attr.ino = FUSE_ROOT_ID;
 663         attr.nlink = 1;
 664         return fuse_iget(sb, 1, 0, &attr, 0, 0);
 665 }
 666
 667 struct fuse_inode_handle {
 668         u64 nodeid;
 669         u32 generation;
 670 };
 671
 672 static struct dentry *fuse_get_dentry(struct super_block *sb,
 673                                       struct fuse_inode_handle *handle)
 674 {
 675         struct fuse_conn *fc = get_fuse_conn_super(sb);
 676         struct inode *inode;
 677         struct dentry *entry;
 678         int err = -ESTALE;
 679
 680         if (handle->nodeid == 0)
 681                 goto out_err;
 682
 683         inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid);
 684         if (!inode) {
 685                 struct fuse_entry_out outarg;
 686                 const struct qstr name = QSTR_INIT(".", 1);
 687
 688                 if (!fc->export_support)
 689                         goto out_err;
 690
 691                 err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg,
 692                                        &inode);
 693                 if (err && err != -ENOENT)
 694                         goto out_err;
 695                 if (err || !inode) {
 696                         err = -ESTALE;
 697                         goto out_err;
 698                 }
 699                 err = -EIO;
 700                 if (get_node_id(inode) != handle->nodeid)
 701                         goto out_iput;
 702         }
 703         err = -ESTALE;
 704         if (inode->i_generation != handle->generation)
 705                 goto out_iput;
 706
 707         entry = d_obtain_alias(inode);
 708         if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID)
 709                 fuse_invalidate_entry_cache(entry);
 710
 711         return entry;
 712
 713  out_iput:
 714         iput(inode);
 715  out_err:
 716         return ERR_PTR(err);
 717 }
 718
 719 static int fuse_encode_fh(struct inode *inode, u32 *fh, int *max_len,
 720                            struct inode *parent)
 721 {
 722         int len = parent ? 6 : 3;
 723         u64 nodeid;
 724         u32 generation;
 725
 726         if (*max_len < len) {
 727                 *max_len = len;
 728                 return  FILEID_INVALID;
 729         }
 730
 731         nodeid = get_fuse_inode(inode)->nodeid;
 732         generation = inode->i_generation;
 733
 734         fh[0] = (u32)(nodeid >> 32);
 735         fh[1] = (u32)(nodeid & 0xffffffff);
 736         fh[2] = generation;
 737
 738         if (parent) {
 739                 nodeid = get_fuse_inode(parent)->nodeid;
 740                 generation = parent->i_generation;
 741
 742                 fh[3] = (u32)(nodeid >> 32);
 743                 fh[4] = (u32)(nodeid & 0xffffffff);
 744                 fh[5] = generation;
 745         }
 746
 747         *max_len = len;
 748         return parent ? 0x82 : 0x81;
 749 }
 750
 751 static struct dentry *fuse_fh_to_dentry(struct super_block *sb,
 752                 struct fid *fid, int fh_len, int fh_type)
 753 {
 754         struct fuse_inode_handle handle;
 755
 756         if ((fh_type != 0x81 && fh_type != 0x82) || fh_len < 3)
 757                 return NULL;
 758
 759         handle.nodeid = (u64) fid->raw[0] << 32;
 760         handle.nodeid |= (u64) fid->raw[1];
 761         handle.generation = fid->raw[2];
 762         return fuse_get_dentry(sb, &handle);
 763 }
 764
 765 static struct dentry *fuse_fh_to_parent(struct super_block *sb,
 766                 struct fid *fid, int fh_len, int fh_type)
 767 {
 768         struct fuse_inode_handle parent;
 769
 770         if (fh_type != 0x82 || fh_len < 6)
 771                 return NULL;
 772
 773         parent.nodeid = (u64) fid->raw[3] << 32;
 774         parent.nodeid |= (u64) fid->raw[4];
 775         parent.generation = fid->raw[5];
 776         return fuse_get_dentry(sb, &parent);
 777 }
 778
 779 static struct dentry *fuse_get_parent(struct dentry *child)
 780 {
 781         struct inode *child_inode = d_inode(child);
 782         struct fuse_conn *fc = get_fuse_conn(child_inode);
 783         struct inode *inode;
 784         struct dentry *parent;
 785         struct fuse_entry_out outarg;
 786         const struct qstr name = QSTR_INIT("..", 2);
 787         int err;
 788
 789         if (!fc->export_support)
 790                 return ERR_PTR(-ESTALE);
 791
 792         err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode),
 793                                &name, &outarg, &inode);
 794         if (err) {
 795                 if (err == -ENOENT)
 796                         return ERR_PTR(-ESTALE);
 797                 return ERR_PTR(err);
 798         }
 799
 800         parent = d_obtain_alias(inode);
 801         if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID)
 802                 fuse_invalidate_entry_cache(parent);
 803
 804         return parent;
 805 }
 806
 807 static const struct export_operations fuse_export_operations = {
 808         .fh_to_dentry   = fuse_fh_to_dentry,
 809         .fh_to_parent   = fuse_fh_to_parent,
 810         .encode_fh      = fuse_encode_fh,
 811         .get_parent     = fuse_get_parent,
 812 };
 813
 814 static const struct super_operations fuse_super_operations = {
 815         .alloc_inode    = fuse_alloc_inode,
 816         .destroy_inode  = fuse_destroy_inode,
 817         .evict_inode    = fuse_evict_inode,
 818         .write_inode    = fuse_write_inode,
 819         .drop_inode     = generic_delete_inode,
 820         .remount_fs     = fuse_remount_fs,
 821         .put_super      = fuse_put_super,
 822         .umount_begin   = fuse_umount_begin,
 823         .statfs         = fuse_statfs,
 824         .show_options   = fuse_show_options,
 825 };
 826
 827 static void sanitize_global_limit(unsigned *limit)
 828 {
 829         if (*limit == 0)
 830                 *limit = ((totalram_pages() << PAGE_SHIFT) >> 13) /
 831                          sizeof(struct fuse_req);
 832
 833         if (*limit >= 1 << 16)
 834                 *limit = (1 << 16) - 1;
 835 }
 836
 837 static int set_global_limit(const char *val, const struct kernel_param *kp)
 838 {
 839         int rv;
 840
 841         rv = param_set_uint(val, kp);
 842         if (rv)
 843                 return rv;
 844
 845         sanitize_global_limit((unsigned *)kp->arg);
 846
 847         return 0;
 848 }
 849
 850 static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg)
 851 {
 852         int cap_sys_admin = capable(CAP_SYS_ADMIN);
 853
 854         if (arg->minor < 13)
 855                 return;
 856
 857         sanitize_global_limit(&max_user_bgreq);
 858         sanitize_global_limit(&max_user_congthresh);
 859
 860         spin_lock(&fc->bg_lock);
 861         if (arg->max_background) {
 862                 fc->max_background = arg->max_background;
 863
 864                 if (!cap_sys_admin && fc->max_background > max_user_bgreq)
 865                         fc->max_background = max_user_bgreq;
 866         }
 867         if (arg->congestion_threshold) {
 868                 fc->congestion_threshold = arg->congestion_threshold;
 869
 870                 if (!cap_sys_admin &&
 871                     fc->congestion_threshold > max_user_congthresh)
 872                         fc->congestion_threshold = max_user_congthresh;
 873         }
 874         spin_unlock(&fc->bg_lock);
 875 }
 876
 877 static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
 878 {
 879         struct fuse_init_out *arg = &req->misc.init_out;
 880
 881         if (req->out.h.error || arg->major != FUSE_KERNEL_VERSION)
 882                 fc->conn_error = 1;
 883         else {
 884                 unsigned long ra_pages;
 885
 886                 process_init_limits(fc, arg);
 887
 888                 if (arg->minor >= 6) {
 889                         ra_pages = arg->max_readahead / PAGE_SIZE;
 890                         if (arg->flags & FUSE_ASYNC_READ)
 891                                 fc->async_read = 1;
 892                         if (!(arg->flags & FUSE_POSIX_LOCKS))
 893                                 fc->no_lock = 1;
 894                         if (arg->minor >= 17) {
 895                                 if (!(arg->flags & FUSE_FLOCK_LOCKS))
 896                                         fc->no_flock = 1;
 897                         } else {
 898                                 if (!(arg->flags & FUSE_POSIX_LOCKS))
 899                                         fc->no_flock = 1;
 900                         }
 901                         if (arg->flags & FUSE_ATOMIC_O_TRUNC)
 902                                 fc->atomic_o_trunc = 1;
 903                         if (arg->minor >= 9) {
 904                                 /* LOOKUP has dependency on proto version */
 905                                 if (arg->flags & FUSE_EXPORT_SUPPORT)
 906                                         fc->export_support = 1;
 907                         }
 908                         if (arg->flags & FUSE_BIG_WRITES)
 909                                 fc->big_writes = 1;
 910                         if (arg->flags & FUSE_DONT_MASK)
 911                                 fc->dont_mask = 1;
 912                         if (arg->flags & FUSE_AUTO_INVAL_DATA)
 913                                 fc->auto_inval_data = 1;
 914                         else if (arg->flags & FUSE_EXPLICIT_INVAL_DATA)
 915                                 fc->explicit_inval_data = 1;
 916                         if (arg->flags & FUSE_DO_READDIRPLUS) {
 917                                 fc->do_readdirplus = 1;
 918                                 if (arg->flags & FUSE_READDIRPLUS_AUTO)
 919                                         fc->readdirplus_auto = 1;
 920                         }
 921                         if (arg->flags & FUSE_ASYNC_DIO)
 922                                 fc->async_dio = 1;
 923                         if (arg->flags & FUSE_WRITEBACK_CACHE)
 924                                 fc->writeback_cache = 1;
 925                         if (arg->flags & FUSE_PARALLEL_DIROPS)
 926                                 fc->parallel_dirops = 1;
 927                         if (arg->flags & FUSE_HANDLE_KILLPRIV)
 928                                 fc->handle_killpriv = 1;
 929                         if (arg->time_gran && arg->time_gran <= 1000000000)
 930                                 fc->sb->s_time_gran = arg->time_gran;
 931                         if ((arg->flags & FUSE_POSIX_ACL)) {
 932                                 fc->default_permissions = 1;
 933                                 fc->posix_acl = 1;
 934                                 fc->sb->s_xattr = fuse_acl_xattr_handlers;
 935                         }
 936                         if (arg->flags & FUSE_CACHE_SYMLINKS)
 937                                 fc->cache_symlinks = 1;
 938                         if (arg->flags & FUSE_ABORT_ERROR)
 939                                 fc->abort_err = 1;
 940                         if (arg->flags & FUSE_MAX_PAGES) {
 941                                 fc->max_pages =
 942                                         min_t(unsigned int, FUSE_MAX_MAX_PAGES,
 943                                         max_t(unsigned int, arg->max_pages, 1));
 944                         }
 945                 } else {
 946                         ra_pages = fc->max_read / PAGE_SIZE;
 947                         fc->no_lock = 1;
 948                         fc->no_flock = 1;
 949                 }
 950
 951                 fc->sb->s_bdi->ra_pages =
 952                                 min(fc->sb->s_bdi->ra_pages, ra_pages);
 953                 fc->minor = arg->minor;
 954                 fc->max_write = arg->minor < 5 ? 4096 : arg->max_write;
 955                 fc->max_write = max_t(unsigned, 4096, fc->max_write);
 956                 fc->conn_init = 1;
 957         }
 958         fuse_set_initialized(fc);
 959         wake_up_all(&fc->blocked_waitq);
 960 }
 961
 962 static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req)
 963 {
 964         struct fuse_init_in *arg = &req->misc.init_in;
 965
 966         arg->major = FUSE_KERNEL_VERSION;
 967         arg->minor = FUSE_KERNEL_MINOR_VERSION;
 968         arg->max_readahead = fc->sb->s_bdi->ra_pages * PAGE_SIZE;
 969         arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC |
 970                 FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK |
 971                 FUSE_SPLICE_WRITE | FUSE_SPLICE_MOVE | FUSE_SPLICE_READ |
 972                 FUSE_FLOCK_LOCKS | FUSE_HAS_IOCTL_DIR | FUSE_AUTO_INVAL_DATA |
 973                 FUSE_DO_READDIRPLUS | FUSE_READDIRPLUS_AUTO | FUSE_ASYNC_DIO |
 974                 FUSE_WRITEBACK_CACHE | FUSE_NO_OPEN_SUPPORT |
 975                 FUSE_PARALLEL_DIROPS | FUSE_HANDLE_KILLPRIV | FUSE_POSIX_ACL |
 976                 FUSE_ABORT_ERROR | FUSE_MAX_PAGES | FUSE_CACHE_SYMLINKS |
 977                 FUSE_NO_OPENDIR_SUPPORT | FUSE_EXPLICIT_INVAL_DATA;
 978         req->in.h.opcode = FUSE_INIT;
 979         req->in.numargs = 1;
 980         req->in.args[0].size = sizeof(*arg);
 981         req->in.args[0].value = arg;
 982         req->out.numargs = 1;
 983         /* Variable length argument used for backward compatibility
 984            with interface version < 7.5.  Rest of init_out is zeroed
 985            by do_get_request(), so a short reply is not a problem */
 986         req->out.argvar = 1;
 987         req->out.args[0].size = sizeof(struct fuse_init_out);
 988         req->out.args[0].value = &req->misc.init_out;
 989         req->end = process_init_reply;
 990         fuse_request_send_background(fc, req);
 991 }
 992
 993 static void fuse_free_conn(struct fuse_conn *fc)
 994 {
 995         WARN_ON(!list_empty(&fc->devices));
 996         kfree_rcu(fc, rcu);
 997 }
 998
 999 static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
1000 {
1001         int err;
1002         char *suffix = "";
1003
1004         if (sb->s_bdev) {
1005                 suffix = "-fuseblk";
1006                 /*
1007                  * sb->s_bdi points to blkdev's bdi however we want to redirect
1008                  * it to our private bdi...
1009                  */
1010                 bdi_put(sb->s_bdi);
1011                 sb->s_bdi = &noop_backing_dev_info;
1012         }
1013         err = super_setup_bdi_name(sb, "%u:%u%s", MAJOR(fc->dev),
1014                                    MINOR(fc->dev), suffix);
1015         if (err)
1016                 return err;
1017
1018         sb->s_bdi->ra_pages = VM_READAHEAD_PAGES;
1019         /* fuse does it's own writeback accounting */
1020         sb->s_bdi->capabilities = BDI_CAP_NO_ACCT_WB | BDI_CAP_STRICTLIMIT;
1021
1022         /*
1023          * For a single fuse filesystem use max 1% of dirty +
1024          * writeback threshold.
1025          *
1026          * This gives about 1M of write buffer for memory maps on a
1027          * machine with 1G and 10% dirty_ratio, which should be more
1028          * than enough.
1029          *
1030          * Privileged users can raise it by writing to
1031          *
1032          *    /sys/class/bdi/<bdi>/max_ratio
1033          */
1034         bdi_set_max_ratio(sb->s_bdi, 1);
1035
1036         return 0;
1037 }
1038
1039 struct fuse_dev *fuse_dev_alloc(struct fuse_conn *fc)
1040 {
1041         struct fuse_dev *fud;
1042         struct list_head *pq;
1043
1044         fud = kzalloc(sizeof(struct fuse_dev), GFP_KERNEL);
1045         if (!fud)
1046                 return NULL;
1047
1048         pq = kcalloc(FUSE_PQ_HASH_SIZE, sizeof(struct list_head), GFP_KERNEL);
1049         if (!pq) {
1050                 kfree(fud);
1051                 return NULL;
1052         }
1053
1054         fud->pq.processing = pq;
1055         fud->fc = fuse_conn_get(fc);
1056         fuse_pqueue_init(&fud->pq);
1057
1058         spin_lock(&fc->lock);
1059         list_add_tail(&fud->entry, &fc->devices);
1060         spin_unlock(&fc->lock);
1061
1062         return fud;
1063 }
1064 EXPORT_SYMBOL_GPL(fuse_dev_alloc);
1065
1066 void fuse_dev_free(struct fuse_dev *fud)
1067 {
1068         struct fuse_conn *fc = fud->fc;
1069
1070         if (fc) {
1071                 spin_lock(&fc->lock);
1072                 list_del(&fud->entry);
1073                 spin_unlock(&fc->lock);
1074
1075                 fuse_conn_put(fc);
1076         }
1077         kfree(fud->pq.processing);
1078         kfree(fud);
1079 }
1080 EXPORT_SYMBOL_GPL(fuse_dev_free);
1081
1082 static int fuse_fill_super(struct super_block *sb, void *data, int silent)
1083 {
1084         struct fuse_dev *fud;
1085         struct fuse_conn *fc;
1086         struct inode *root;
1087         struct fuse_mount_data d;
1088         struct file *file;
1089         struct dentry *root_dentry;
1090         struct fuse_req *init_req;
1091         int err;
1092         int is_bdev = sb->s_bdev != NULL;
1093
1094         err = -EINVAL;
1095         if (sb->s_flags & SB_MANDLOCK)
1096                 goto err;
1097
1098         sb->s_flags &= ~(SB_NOSEC | SB_I_VERSION);
1099
1100         if (!parse_fuse_opt(data, &d, is_bdev, sb->s_user_ns))
1101                 goto err;
1102
1103         if (is_bdev) {
1104 #ifdef CONFIG_BLOCK
1105                 err = -EINVAL;
1106                 if (!sb_set_blocksize(sb, d.blksize))
1107                         goto err;
1108 #endif
1109         } else {
1110                 sb->s_blocksize = PAGE_SIZE;
1111                 sb->s_blocksize_bits = PAGE_SHIFT;
1112         }
1113         sb->s_magic = FUSE_SUPER_MAGIC;
1114         sb->s_op = &fuse_super_operations;
1115         sb->s_xattr = fuse_xattr_handlers;
1116         sb->s_maxbytes = MAX_LFS_FILESIZE;
1117         sb->s_time_gran = 1;
1118         sb->s_export_op = &fuse_export_operations;
1119         sb->s_iflags |= SB_I_IMA_UNVERIFIABLE_SIGNATURE;
1120         if (sb->s_user_ns != &init_user_ns)
1121                 sb->s_iflags |= SB_I_UNTRUSTED_MOUNTER;
1122
1123         file = fget(d.fd);
1124         err = -EINVAL;
1125         if (!file)
1126                 goto err;
1127
1128         /*
1129          * Require mount to happen from the same user namespace which
1130          * opened /dev/fuse to prevent potential attacks.
1131          */
1132         if (file->f_op != &fuse_dev_operations ||
1133             file->f_cred->user_ns != sb->s_user_ns)
1134                 goto err_fput;
1135
1136         /*
1137          * If we are not in the initial user namespace posix
1138          * acls must be translated.
1139          */
1140         if (sb->s_user_ns != &init_user_ns)
1141                 sb->s_xattr = fuse_no_acl_xattr_handlers;
1142
1143         fc = kmalloc(sizeof(*fc), GFP_KERNEL);
1144         err = -ENOMEM;
1145         if (!fc)
1146                 goto err_fput;
1147
1148         fuse_conn_init(fc, sb->s_user_ns);
1149         fc->release = fuse_free_conn;
1150
1151         fud = fuse_dev_alloc(fc);
1152         if (!fud)
1153                 goto err_put_conn;
1154
1155         fc->dev = sb->s_dev;
1156         fc->sb = sb;
1157         err = fuse_bdi_init(fc, sb);
1158         if (err)
1159                 goto err_dev_free;
1160
1161         /* Handle umasking inside the fuse code */
1162         if (sb->s_flags & SB_POSIXACL)
1163                 fc->dont_mask = 1;
1164         sb->s_flags |= SB_POSIXACL;
1165
1166         fc->default_permissions = d.default_permissions;
1167         fc->allow_other = d.allow_other;
1168         fc->user_id = d.user_id;
1169         fc->group_id = d.group_id;
1170         fc->max_read = max_t(unsigned, 4096, d.max_read);
1171
1172         /* Used by get_root_inode() */
1173         sb->s_fs_info = fc;
1174
1175         err = -ENOMEM;
1176         root = fuse_get_root_inode(sb, d.rootmode);
1177         sb->s_d_op = &fuse_root_dentry_operations;
1178         root_dentry = d_make_root(root);
1179         if (!root_dentry)
1180                 goto err_dev_free;
1181         /* Root dentry doesn't have .d_revalidate */
1182         sb->s_d_op = &fuse_dentry_operations;
1183
1184         init_req = fuse_request_alloc(0);
1185         if (!init_req)
1186                 goto err_put_root;
1187         __set_bit(FR_BACKGROUND, &init_req->flags);
1188
1189         if (is_bdev) {
1190                 fc->destroy_req = fuse_request_alloc(0);
1191                 if (!fc->destroy_req)
1192                         goto err_free_init_req;
1193         }
1194
1195         mutex_lock(&fuse_mutex);
1196         err = -EINVAL;
1197         if (file->private_data)
1198                 goto err_unlock;
1199
1200         err = fuse_ctl_add_conn(fc);
1201         if (err)
1202                 goto err_unlock;
1203
1204         list_add_tail(&fc->entry, &fuse_conn_list);
1205         sb->s_root = root_dentry;
1206         file->private_data = fud;
1207         mutex_unlock(&fuse_mutex);
1208         /*
1209          * atomic_dec_and_test() in fput() provides the necessary
1210          * memory barrier for file->private_data to be visible on all
1211          * CPUs after this
1212          */
1213         fput(file);
1214
1215         fuse_send_init(fc, init_req);
1216
1217         return 0;
1218
1219  err_unlock:
1220         mutex_unlock(&fuse_mutex);
1221  err_free_init_req:
1222         fuse_request_free(init_req);
1223  err_put_root:
1224         dput(root_dentry);
1225  err_dev_free:
1226         fuse_dev_free(fud);
1227  err_put_conn:
1228         fuse_conn_put(fc);
1229         sb->s_fs_info = NULL;
1230  err_fput:
1231         fput(file);
1232  err:
1233         return err;
1234 }
1235
1236 static struct dentry *fuse_mount(struct file_system_type *fs_type,
1237                        int flags, const char *dev_name,
1238                        void *raw_data)
1239 {
1240         return mount_nodev(fs_type, flags, raw_data, fuse_fill_super);
1241 }
1242
1243 static void fuse_sb_destroy(struct super_block *sb)
1244 {
1245         struct fuse_conn *fc = get_fuse_conn_super(sb);
1246
1247         if (fc) {
1248                 fuse_send_destroy(fc);
1249
1250                 fuse_abort_conn(fc);
1251                 fuse_wait_aborted(fc);
1252
1253                 down_write(&fc->killsb);
1254                 fc->sb = NULL;
1255                 up_write(&fc->killsb);
1256         }
1257 }
1258
1259 static void fuse_kill_sb_anon(struct super_block *sb)
1260 {
1261         fuse_sb_destroy(sb);
1262         kill_anon_super(sb);
1263 }
1264
1265 static struct file_system_type fuse_fs_type = {
1266         .owner          = THIS_MODULE,
1267         .name           = "fuse",
1268         .fs_flags       = FS_HAS_SUBTYPE | FS_USERNS_MOUNT,
1269         .mount          = fuse_mount,
1270         .kill_sb        = fuse_kill_sb_anon,
1271 };
1272 MODULE_ALIAS_FS("fuse");
1273
1274 #ifdef CONFIG_BLOCK
1275 static struct dentry *fuse_mount_blk(struct file_system_type *fs_type,
1276                            int flags, const char *dev_name,
1277                            void *raw_data)
1278 {
1279         return mount_bdev(fs_type, flags, dev_name, raw_data, fuse_fill_super);
1280 }
1281
1282 static void fuse_kill_sb_blk(struct super_block *sb)
1283 {
1284         fuse_sb_destroy(sb);
1285         kill_block_super(sb);
1286 }
1287
1288 static struct file_system_type fuseblk_fs_type = {
1289         .owner          = THIS_MODULE,
1290         .name           = "fuseblk",
1291         .mount          = fuse_mount_blk,
1292         .kill_sb        = fuse_kill_sb_blk,
1293         .fs_flags       = FS_REQUIRES_DEV | FS_HAS_SUBTYPE,
1294 };
1295 MODULE_ALIAS_FS("fuseblk");
1296
1297 static inline int register_fuseblk(void)
1298 {
1299         return register_filesystem(&fuseblk_fs_type);
1300 }
1301
1302 static inline void unregister_fuseblk(void)
1303 {
1304         unregister_filesystem(&fuseblk_fs_type);
1305 }
1306 #else
1307 static inline int register_fuseblk(void)
1308 {
1309         return 0;
1310 }
1311
1312 static inline void unregister_fuseblk(void)
1313 {
1314 }
1315 #endif
1316
1317 static void fuse_inode_init_once(void *foo)
1318 {
1319         struct inode *inode = foo;
1320
1321         inode_init_once(inode);
1322 }
1323
1324 static int __init fuse_fs_init(void)
1325 {
1326         int err;
1327
1328         fuse_inode_cachep = kmem_cache_create("fuse_inode",
1329                         sizeof(struct fuse_inode), 0,
1330                         SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT|SLAB_RECLAIM_ACCOUNT,
1331                         fuse_inode_init_once);
1332         err = -ENOMEM;
1333         if (!fuse_inode_cachep)
1334                 goto out;
1335
1336         err = register_fuseblk();
1337         if (err)
1338                 goto out2;
1339
1340         err = register_filesystem(&fuse_fs_type);
1341         if (err)
1342                 goto out3;
1343
1344         return 0;
1345
1346  out3:
1347         unregister_fuseblk();
1348  out2:
1349         kmem_cache_destroy(fuse_inode_cachep);
1350  out:
1351         return err;
1352 }
1353
1354 static void fuse_fs_cleanup(void)
1355 {
1356         unregister_filesystem(&fuse_fs_type);
1357         unregister_fuseblk();
1358
1359         /*
1360          * Make sure all delayed rcu free inodes are flushed before we
1361          * destroy cache.
1362          */
1363         rcu_barrier();
1364         kmem_cache_destroy(fuse_inode_cachep);
1365 }
1366
1367 static struct kobject *fuse_kobj;
1368
1369 static int fuse_sysfs_init(void)
1370 {
1371         int err;
1372
1373         fuse_kobj = kobject_create_and_add("fuse", fs_kobj);
1374         if (!fuse_kobj) {
1375                 err = -ENOMEM;
1376                 goto out_err;
1377         }
1378
1379         err = sysfs_create_mount_point(fuse_kobj, "connections");
1380         if (err)
1381                 goto out_fuse_unregister;
1382
1383         return 0;
1384
1385  out_fuse_unregister:
1386         kobject_put(fuse_kobj);
1387  out_err:
1388         return err;
1389 }
1390
1391 static void fuse_sysfs_cleanup(void)
1392 {
1393         sysfs_remove_mount_point(fuse_kobj, "connections");
1394         kobject_put(fuse_kobj);
1395 }
1396
1397 static int __init fuse_init(void)
1398 {
1399         int res;
1400
1401         pr_info("init (API version %i.%i)\n",
1402                 FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);
1403
1404         INIT_LIST_HEAD(&fuse_conn_list);
1405         res = fuse_fs_init();
1406         if (res)
1407                 goto err;
1408
1409         res = fuse_dev_init();
1410         if (res)
1411                 goto err_fs_cleanup;
1412
1413         res = fuse_sysfs_init();
1414         if (res)
1415                 goto err_dev_cleanup;
1416
1417         res = fuse_ctl_init();
1418         if (res)
1419                 goto err_sysfs_cleanup;
1420
1421         sanitize_global_limit(&max_user_bgreq);
1422         sanitize_global_limit(&max_user_congthresh);
1423
1424         return 0;
1425
1426  err_sysfs_cleanup:
1427         fuse_sysfs_cleanup();
1428  err_dev_cleanup:
1429         fuse_dev_cleanup();
1430  err_fs_cleanup:
1431         fuse_fs_cleanup();
1432  err:
1433         return res;
1434 }
1435
1436 static void __exit fuse_exit(void)
1437 {
1438         pr_debug("exit\n");
1439
1440         fuse_ctl_cleanup();
1441         fuse_sysfs_cleanup();
1442         fuse_fs_cleanup();
1443         fuse_dev_cleanup();
1444 }
1445
1446 module_init(fuse_init);
1447 module_exit(fuse_exit);