fs/fuse/inode.c

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