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