fs/fuse/inode.c

   1 /*
   2   FUSE: Filesystem in Userspace
   3   Copyright (C) 2001-2008  Miklos Szeredi <miklos@szeredi.hu>
   4
   5   This program can be distributed under the terms of the GNU GPL.
   6   See the file COPYING.
   7 */
   8
   9 #include "fuse_i.h"
  10
  11 #include <linux/pagemap.h>
  12 #include <linux/slab.h>
  13 #include <linux/file.h>
  14 #include <linux/seq_file.h>
  15 #include <linux/init.h>
  16 #include <linux/module.h>
  17 #include <linux/moduleparam.h>
  18 #include <linux/fs_context.h>
  19 #include <linux/fs_parser.h>
  20 #include <linux/statfs.h>
  21 #include <linux/random.h>
  22 #include <linux/sched.h>
  23 #include <linux/exportfs.h>
  24 #include <linux/posix_acl.h>
  25 #include <linux/pid_namespace.h>
  26
  27 MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
  28 MODULE_DESCRIPTION("Filesystem in Userspace");
  29 MODULE_LICENSE("GPL");
  30
  31 static struct kmem_cache *fuse_inode_cachep;
  32 struct list_head fuse_conn_list;
  33 DEFINE_MUTEX(fuse_mutex);
  34
  35 static int set_global_limit(const char *val, const struct kernel_param *kp);
  36
  37 unsigned max_user_bgreq;
  38 module_param_call(max_user_bgreq, set_global_limit, param_get_uint,
  39                   &max_user_bgreq, 0644);
  40 __MODULE_PARM_TYPE(max_user_bgreq, "uint");
  41 MODULE_PARM_DESC(max_user_bgreq,
  42  "Global limit for the maximum number of backgrounded requests an "
  43  "unprivileged user can set");
  44
  45 unsigned max_user_congthresh;
  46 module_param_call(max_user_congthresh, set_global_limit, param_get_uint,
  47                   &max_user_congthresh, 0644);
  48 __MODULE_PARM_TYPE(max_user_congthresh, "uint");
  49 MODULE_PARM_DESC(max_user_congthresh,
  50  "Global limit for the maximum congestion threshold an "
  51  "unprivileged user can set");
  52
  53 #define FUSE_SUPER_MAGIC 0x65735546
  54
  55 #define FUSE_DEFAULT_BLKSIZE 512
  56
  57 /** Maximum number of outstanding background requests */
  58 #define FUSE_DEFAULT_MAX_BACKGROUND 12
  59
  60 /** Congestion starts at 75% of maximum */
  61 #define FUSE_DEFAULT_CONGESTION_THRESHOLD (FUSE_DEFAULT_MAX_BACKGROUND * 3 / 4)
  62
  63 #ifdef CONFIG_BLOCK
  64 static struct file_system_type fuseblk_fs_type;
  65 #endif
  66
  67 struct fuse_forget_link *fuse_alloc_forget(void)
  68 {
  69         return kzalloc(sizeof(struct fuse_forget_link), GFP_KERNEL_ACCOUNT);
  70 }
  71
  72 static struct inode *fuse_alloc_inode(struct super_block *sb)
  73 {
  74         struct fuse_inode *fi;
  75
  76         fi = kmem_cache_alloc(fuse_inode_cachep, GFP_KERNEL);
  77         if (!fi)
  78                 return NULL;
  79
  80         fi->i_time = 0;
  81         fi->inval_mask = 0;
  82         fi->nodeid = 0;
  83         fi->nlookup = 0;
  84         fi->attr_version = 0;
  85         fi->orig_ino = 0;
  86         fi->state = 0;
  87         mutex_init(&fi->mutex);
  88         init_rwsem(&fi->i_mmap_sem);
  89         spin_lock_init(&fi->lock);
  90         fi->forget = fuse_alloc_forget();
  91         if (!fi->forget)
  92                 goto out_free;
  93
  94         if (IS_ENABLED(CONFIG_FUSE_DAX) && !fuse_dax_inode_alloc(sb, fi))
  95                 goto out_free_forget;
  96
  97         return &fi->inode;
  98
  99 out_free_forget:
 100         kfree(fi->forget);
 101 out_free:
 102         kmem_cache_free(fuse_inode_cachep, fi);
 103         return NULL;
 104 }
 105
 106 static void fuse_free_inode(struct inode *inode)
 107 {
 108         struct fuse_inode *fi = get_fuse_inode(inode);
 109
 110         mutex_destroy(&fi->mutex);
 111         kfree(fi->forget);
 112 #ifdef CONFIG_FUSE_DAX
 113         kfree(fi->dax);
 114 #endif
 115         kmem_cache_free(fuse_inode_cachep, fi);
 116 }
 117
 118 static void fuse_evict_inode(struct inode *inode)
 119 {
 120         struct fuse_inode *fi = get_fuse_inode(inode);
 121
 122         truncate_inode_pages_final(&inode->i_data);
 123         clear_inode(inode);
 124         if (inode->i_sb->s_flags & SB_ACTIVE) {
 125                 struct fuse_conn *fc = get_fuse_conn(inode);
 126
 127                 if (FUSE_IS_DAX(inode))
 128                         fuse_dax_inode_cleanup(inode);
 129                 if (fi->nlookup) {
 130                         fuse_queue_forget(fc, fi->forget, fi->nodeid,
 131                                           fi->nlookup);
 132                         fi->forget = NULL;
 133                 }
 134         }
 135         if (S_ISREG(inode->i_mode) && !is_bad_inode(inode)) {
 136                 WARN_ON(!list_empty(&fi->write_files));
 137                 WARN_ON(!list_empty(&fi->queued_writes));
 138         }
 139 }
 140
 141 static int fuse_reconfigure(struct fs_context *fc)
 142 {
 143         struct super_block *sb = fc->root->d_sb;
 144
 145         sync_filesystem(sb);
 146         if (fc->sb_flags & SB_MANDLOCK)
 147                 return -EINVAL;
 148
 149         return 0;
 150 }
 151
 152 /*
 153  * ino_t is 32-bits on 32-bit arch. We have to squash the 64-bit value down
 154  * so that it will fit.
 155  */
 156 static ino_t fuse_squash_ino(u64 ino64)
 157 {
 158         ino_t ino = (ino_t) ino64;
 159         if (sizeof(ino_t) < sizeof(u64))
 160                 ino ^= ino64 >> (sizeof(u64) - sizeof(ino_t)) * 8;
 161         return ino;
 162 }
 163
 164 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
 165                                    u64 attr_valid)
 166 {
 167         struct fuse_conn *fc = get_fuse_conn(inode);
 168         struct fuse_inode *fi = get_fuse_inode(inode);
 169
 170         lockdep_assert_held(&fi->lock);
 171
 172         fi->attr_version = atomic64_inc_return(&fc->attr_version);
 173         fi->i_time = attr_valid;
 174         WRITE_ONCE(fi->inval_mask, 0);
 175
 176         inode->i_ino     = fuse_squash_ino(attr->ino);
 177         inode->i_mode    = (inode->i_mode & S_IFMT) | (attr->mode & 07777);
 178         set_nlink(inode, attr->nlink);
 179         inode->i_uid     = make_kuid(fc->user_ns, attr->uid);
 180         inode->i_gid     = make_kgid(fc->user_ns, attr->gid);
 181         inode->i_blocks  = attr->blocks;
 182         inode->i_atime.tv_sec   = attr->atime;
 183         inode->i_atime.tv_nsec  = attr->atimensec;
 184         /* mtime from server may be stale due to local buffered write */
 185         if (!fc->writeback_cache || !S_ISREG(inode->i_mode)) {
 186                 inode->i_mtime.tv_sec   = attr->mtime;
 187                 inode->i_mtime.tv_nsec  = attr->mtimensec;
 188                 inode->i_ctime.tv_sec   = attr->ctime;
 189                 inode->i_ctime.tv_nsec  = attr->ctimensec;
 190         }
 191
 192         if (attr->blksize != 0)
 193                 inode->i_blkbits = ilog2(attr->blksize);
 194         else
 195                 inode->i_blkbits = inode->i_sb->s_blocksize_bits;
 196
 197         /*
 198          * Don't set the sticky bit in i_mode, unless we want the VFS
 199          * to check permissions.  This prevents failures due to the
 200          * check in may_delete().
 201          */
 202         fi->orig_i_mode = inode->i_mode;
 203         if (!fc->default_permissions)
 204                 inode->i_mode &= ~S_ISVTX;
 205
 206         fi->orig_ino = attr->ino;
 207 }
 208
 209 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
 210                             u64 attr_valid, u64 attr_version)
 211 {
 212         struct fuse_conn *fc = get_fuse_conn(inode);
 213         struct fuse_inode *fi = get_fuse_inode(inode);
 214         bool is_wb = fc->writeback_cache;
 215         loff_t oldsize;
 216         struct timespec64 old_mtime;
 217
 218         spin_lock(&fi->lock);
 219         if ((attr_version != 0 && fi->attr_version > attr_version) ||
 220             test_bit(FUSE_I_SIZE_UNSTABLE, &fi->state)) {
 221                 spin_unlock(&fi->lock);
 222                 return;
 223         }
 224
 225         old_mtime = inode->i_mtime;
 226         fuse_change_attributes_common(inode, attr, attr_valid);
 227
 228         oldsize = inode->i_size;
 229         /*
 230          * In case of writeback_cache enabled, the cached writes beyond EOF
 231          * extend local i_size without keeping userspace server in sync. So,
 232          * attr->size coming from server can be stale. We cannot trust it.
 233          */
 234         if (!is_wb || !S_ISREG(inode->i_mode))
 235                 i_size_write(inode, attr->size);
 236         spin_unlock(&fi->lock);
 237
 238         if (!is_wb && S_ISREG(inode->i_mode)) {
 239                 bool inval = false;
 240
 241                 if (oldsize != attr->size) {
 242                         truncate_pagecache(inode, attr->size);
 243                         if (!fc->explicit_inval_data)
 244                                 inval = true;
 245                 } else if (fc->auto_inval_data) {
 246                         struct timespec64 new_mtime = {
 247                                 .tv_sec = attr->mtime,
 248                                 .tv_nsec = attr->mtimensec,
 249                         };
 250
 251                         /*
 252                          * Auto inval mode also checks and invalidates if mtime
 253                          * has changed.
 254                          */
 255                         if (!timespec64_equal(&old_mtime, &new_mtime))
 256                                 inval = true;
 257                 }
 258
 259                 if (inval)
 260                         invalidate_inode_pages2(inode->i_mapping);
 261         }
 262 }
 263
 264 static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr)
 265 {
 266         inode->i_mode = attr->mode & S_IFMT;
 267         inode->i_size = attr->size;
 268         inode->i_mtime.tv_sec  = attr->mtime;
 269         inode->i_mtime.tv_nsec = attr->mtimensec;
 270         inode->i_ctime.tv_sec  = attr->ctime;
 271         inode->i_ctime.tv_nsec = attr->ctimensec;
 272         if (S_ISREG(inode->i_mode)) {
 273                 fuse_init_common(inode);
 274                 fuse_init_file_inode(inode);
 275         } else if (S_ISDIR(inode->i_mode))
 276                 fuse_init_dir(inode);
 277         else if (S_ISLNK(inode->i_mode))
 278                 fuse_init_symlink(inode);
 279         else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
 280                  S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
 281                 fuse_init_common(inode);
 282                 init_special_inode(inode, inode->i_mode,
 283                                    new_decode_dev(attr->rdev));
 284         } else
 285                 BUG();
 286 }
 287
 288 static int fuse_inode_eq(struct inode *inode, void *_nodeidp)
 289 {
 290         u64 nodeid = *(u64 *) _nodeidp;
 291         if (get_node_id(inode) == nodeid)
 292                 return 1;
 293         else
 294                 return 0;
 295 }
 296
 297 static int fuse_inode_set(struct inode *inode, void *_nodeidp)
 298 {
 299         u64 nodeid = *(u64 *) _nodeidp;
 300         get_fuse_inode(inode)->nodeid = nodeid;
 301         return 0;
 302 }
 303
 304 struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
 305                         int generation, struct fuse_attr *attr,
 306                         u64 attr_valid, u64 attr_version)
 307 {
 308         struct inode *inode;
 309         struct fuse_inode *fi;
 310         struct fuse_conn *fc = get_fuse_conn_super(sb);
 311
 312         /*
 313          * Auto mount points get their node id from the submount root, which is
 314          * not a unique identifier within this filesystem.
 315          *
 316          * To avoid conflicts, do not place submount points into the inode hash
 317          * table.
 318          */
 319         if (fc->auto_submounts && (attr->flags & FUSE_ATTR_SUBMOUNT) &&
 320             S_ISDIR(attr->mode)) {
 321                 inode = new_inode(sb);
 322                 if (!inode)
 323                         return NULL;
 324
 325                 fuse_init_inode(inode, attr);
 326                 get_fuse_inode(inode)->nodeid = nodeid;
 327                 inode->i_flags |= S_AUTOMOUNT;
 328                 goto done;
 329         }
 330
 331 retry:
 332         inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid);
 333         if (!inode)
 334                 return NULL;
 335
 336         if ((inode->i_state & I_NEW)) {
 337                 inode->i_flags |= S_NOATIME;
 338                 if (!fc->writeback_cache || !S_ISREG(attr->mode))
 339                         inode->i_flags |= S_NOCMTIME;
 340                 inode->i_generation = generation;
 341                 fuse_init_inode(inode, attr);
 342                 unlock_new_inode(inode);
 343         } else if ((inode->i_mode ^ attr->mode) & S_IFMT) {
 344                 /* Inode has changed type, any I/O on the old should fail */
 345                 make_bad_inode(inode);
 346                 iput(inode);
 347                 goto retry;
 348         }
 349 done:
 350         fi = get_fuse_inode(inode);
 351         spin_lock(&fi->lock);
 352         fi->nlookup++;
 353         spin_unlock(&fi->lock);
 354         fuse_change_attributes(inode, attr, attr_valid, attr_version);
 355
 356         return inode;
 357 }
 358
 359 struct inode *fuse_ilookup(struct fuse_conn *fc, u64 nodeid,
 360                            struct fuse_mount **fm)
 361 {
 362         struct fuse_mount *fm_iter;
 363         struct inode *inode;
 364
 365         WARN_ON(!rwsem_is_locked(&fc->killsb));
 366         list_for_each_entry(fm_iter, &fc->mounts, fc_entry) {
 367                 if (!fm_iter->sb)
 368                         continue;
 369
 370                 inode = ilookup5(fm_iter->sb, nodeid, fuse_inode_eq, &nodeid);
 371                 if (inode) {
 372                         if (fm)
 373                                 *fm = fm_iter;
 374                         return inode;
 375                 }
 376         }
 377
 378         return NULL;
 379 }
 380
 381 int fuse_reverse_inval_inode(struct fuse_conn *fc, u64 nodeid,
 382                              loff_t offset, loff_t len)
 383 {
 384         struct fuse_inode *fi;
 385         struct inode *inode;
 386         pgoff_t pg_start;
 387         pgoff_t pg_end;
 388
 389         inode = fuse_ilookup(fc, nodeid, NULL);
 390         if (!inode)
 391                 return -ENOENT;
 392
 393         fi = get_fuse_inode(inode);
 394         spin_lock(&fi->lock);
 395         fi->attr_version = atomic64_inc_return(&fc->attr_version);
 396         spin_unlock(&fi->lock);
 397
 398         fuse_invalidate_attr(inode);
 399         forget_all_cached_acls(inode);
 400         if (offset >= 0) {
 401                 pg_start = offset >> PAGE_SHIFT;
 402                 if (len <= 0)
 403                         pg_end = -1;
 404                 else
 405                         pg_end = (offset + len - 1) >> PAGE_SHIFT;
 406                 invalidate_inode_pages2_range(inode->i_mapping,
 407                                               pg_start, pg_end);
 408         }
 409         iput(inode);
 410         return 0;
 411 }
 412
 413 bool fuse_lock_inode(struct inode *inode)
 414 {
 415         bool locked = false;
 416
 417         if (!get_fuse_conn(inode)->parallel_dirops) {
 418                 mutex_lock(&get_fuse_inode(inode)->mutex);
 419                 locked = true;
 420         }
 421
 422         return locked;
 423 }
 424
 425 void fuse_unlock_inode(struct inode *inode, bool locked)
 426 {
 427         if (locked)
 428                 mutex_unlock(&get_fuse_inode(inode)->mutex);
 429 }
 430
 431 static void fuse_umount_begin(struct super_block *sb)
 432 {
 433         struct fuse_conn *fc = get_fuse_conn_super(sb);
 434
 435         if (!fc->no_force_umount)
 436                 fuse_abort_conn(fc);
 437 }
 438
 439 static void fuse_send_destroy(struct fuse_mount *fm)
 440 {
 441         if (fm->fc->conn_init) {
 442                 FUSE_ARGS(args);
 443
 444                 args.opcode = FUSE_DESTROY;
 445                 args.force = true;
 446                 args.nocreds = true;
 447                 fuse_simple_request(fm, &args);
 448         }
 449 }
 450
 451 static void fuse_put_super(struct super_block *sb)
 452 {
 453         struct fuse_mount *fm = get_fuse_mount_super(sb);
 454
 455         fuse_conn_put(fm->fc);
 456         kfree(fm);
 457 }
 458
 459 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr)
 460 {
 461         stbuf->f_type    = FUSE_SUPER_MAGIC;
 462         stbuf->f_bsize   = attr->bsize;
 463         stbuf->f_frsize  = attr->frsize;
 464         stbuf->f_blocks  = attr->blocks;
 465         stbuf->f_bfree   = attr->bfree;
 466         stbuf->f_bavail  = attr->bavail;
 467         stbuf->f_files   = attr->files;
 468         stbuf->f_ffree   = attr->ffree;
 469         stbuf->f_namelen = attr->namelen;
 470         /* fsid is left zero */
 471 }
 472
 473 static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf)
 474 {
 475         struct super_block *sb = dentry->d_sb;
 476         struct fuse_mount *fm = get_fuse_mount_super(sb);
 477         FUSE_ARGS(args);
 478         struct fuse_statfs_out outarg;
 479         int err;
 480
 481         if (!fuse_allow_current_process(fm->fc)) {
 482                 buf->f_type = FUSE_SUPER_MAGIC;
 483                 return 0;
 484         }
 485
 486         memset(&outarg, 0, sizeof(outarg));
 487         args.in_numargs = 0;
 488         args.opcode = FUSE_STATFS;
 489         args.nodeid = get_node_id(d_inode(dentry));
 490         args.out_numargs = 1;
 491         args.out_args[0].size = sizeof(outarg);
 492         args.out_args[0].value = &outarg;
 493         err = fuse_simple_request(fm, &args);
 494         if (!err)
 495                 convert_fuse_statfs(buf, &outarg.st);
 496         return err;
 497 }
 498
 499 enum {
 500         OPT_SOURCE,
 501         OPT_SUBTYPE,
 502         OPT_FD,
 503         OPT_ROOTMODE,
 504         OPT_USER_ID,
 505         OPT_GROUP_ID,
 506         OPT_DEFAULT_PERMISSIONS,
 507         OPT_ALLOW_OTHER,
 508         OPT_MAX_READ,
 509         OPT_BLKSIZE,
 510         OPT_ERR
 511 };
 512
 513 static const struct fs_parameter_spec fuse_fs_parameters[] = {
 514         fsparam_string  ("source",              OPT_SOURCE),
 515         fsparam_u32     ("fd",                  OPT_FD),
 516         fsparam_u32oct  ("rootmode",            OPT_ROOTMODE),
 517         fsparam_u32     ("user_id",             OPT_USER_ID),
 518         fsparam_u32     ("group_id",            OPT_GROUP_ID),
 519         fsparam_flag    ("default_permissions", OPT_DEFAULT_PERMISSIONS),
 520         fsparam_flag    ("allow_other",         OPT_ALLOW_OTHER),
 521         fsparam_u32     ("max_read",            OPT_MAX_READ),
 522         fsparam_u32     ("blksize",             OPT_BLKSIZE),
 523         fsparam_string  ("subtype",             OPT_SUBTYPE),
 524         {}
 525 };
 526
 527 static int fuse_parse_param(struct fs_context *fc, struct fs_parameter *param)
 528 {
 529         struct fs_parse_result result;
 530         struct fuse_fs_context *ctx = fc->fs_private;
 531         int opt;
 532
 533         if (fc->purpose == FS_CONTEXT_FOR_RECONFIGURE) {
 534                 /*
 535                  * Ignore options coming from mount(MS_REMOUNT) for backward
 536                  * compatibility.
 537                  */
 538                 if (fc->oldapi)
 539                         return 0;
 540
 541                 return invalfc(fc, "No changes allowed in reconfigure");
 542         }
 543
 544         opt = fs_parse(fc, fuse_fs_parameters, param, &result);
 545         if (opt < 0)
 546                 return opt;
 547
 548         switch (opt) {
 549         case OPT_SOURCE:
 550                 if (fc->source)
 551                         return invalfc(fc, "Multiple sources specified");
 552                 fc->source = param->string;
 553                 param->string = NULL;
 554                 break;
 555
 556         case OPT_SUBTYPE:
 557                 if (ctx->subtype)
 558                         return invalfc(fc, "Multiple subtypes specified");
 559                 ctx->subtype = param->string;
 560                 param->string = NULL;
 561                 return 0;
 562
 563         case OPT_FD:
 564                 ctx->fd = result.uint_32;
 565                 ctx->fd_present = true;
 566                 break;
 567
 568         case OPT_ROOTMODE:
 569                 if (!fuse_valid_type(result.uint_32))
 570                         return invalfc(fc, "Invalid rootmode");
 571                 ctx->rootmode = result.uint_32;
 572                 ctx->rootmode_present = true;
 573                 break;
 574
 575         case OPT_USER_ID:
 576                 ctx->user_id = make_kuid(fc->user_ns, result.uint_32);
 577                 if (!uid_valid(ctx->user_id))
 578                         return invalfc(fc, "Invalid user_id");
 579                 ctx->user_id_present = true;
 580                 break;
 581
 582         case OPT_GROUP_ID:
 583                 ctx->group_id = make_kgid(fc->user_ns, result.uint_32);
 584                 if (!gid_valid(ctx->group_id))
 585                         return invalfc(fc, "Invalid group_id");
 586                 ctx->group_id_present = true;
 587                 break;
 588
 589         case OPT_DEFAULT_PERMISSIONS:
 590                 ctx->default_permissions = true;
 591                 break;
 592
 593         case OPT_ALLOW_OTHER:
 594                 ctx->allow_other = true;
 595                 break;
 596
 597         case OPT_MAX_READ:
 598                 ctx->max_read = result.uint_32;
 599                 break;
 600
 601         case OPT_BLKSIZE:
 602                 if (!ctx->is_bdev)
 603                         return invalfc(fc, "blksize only supported for fuseblk");
 604                 ctx->blksize = result.uint_32;
 605                 break;
 606
 607         default:
 608                 return -EINVAL;
 609         }
 610
 611         return 0;
 612 }
 613
 614 static void fuse_free_fc(struct fs_context *fc)
 615 {
 616         struct fuse_fs_context *ctx = fc->fs_private;
 617
 618         if (ctx) {
 619                 kfree(ctx->subtype);
 620                 kfree(ctx);
 621         }
 622 }
 623
 624 static int fuse_show_options(struct seq_file *m, struct dentry *root)
 625 {
 626         struct super_block *sb = root->d_sb;
 627         struct fuse_conn *fc = get_fuse_conn_super(sb);
 628
 629         if (fc->legacy_opts_show) {
 630                 seq_printf(m, ",user_id=%u",
 631                            from_kuid_munged(fc->user_ns, fc->user_id));
 632                 seq_printf(m, ",group_id=%u",
 633                            from_kgid_munged(fc->user_ns, fc->group_id));
 634                 if (fc->default_permissions)
 635                         seq_puts(m, ",default_permissions");
 636                 if (fc->allow_other)
 637                         seq_puts(m, ",allow_other");
 638                 if (fc->max_read != ~0)
 639                         seq_printf(m, ",max_read=%u", fc->max_read);
 640                 if (sb->s_bdev && sb->s_blocksize != FUSE_DEFAULT_BLKSIZE)
 641                         seq_printf(m, ",blksize=%lu", sb->s_blocksize);
 642         }
 643 #ifdef CONFIG_FUSE_DAX
 644         if (fc->dax)
 645                 seq_puts(m, ",dax");
 646 #endif
 647
 648         return 0;
 649 }
 650
 651 static void fuse_iqueue_init(struct fuse_iqueue *fiq,
 652                              const struct fuse_iqueue_ops *ops,
 653                              void *priv)
 654 {
 655         memset(fiq, 0, sizeof(struct fuse_iqueue));
 656         spin_lock_init(&fiq->lock);
 657         init_waitqueue_head(&fiq->waitq);
 658         INIT_LIST_HEAD(&fiq->pending);
 659         INIT_LIST_HEAD(&fiq->interrupts);
 660         fiq->forget_list_tail = &fiq->forget_list_head;
 661         fiq->connected = 1;
 662         fiq->ops = ops;
 663         fiq->priv = priv;
 664 }
 665
 666 static void fuse_pqueue_init(struct fuse_pqueue *fpq)
 667 {
 668         unsigned int i;
 669
 670         spin_lock_init(&fpq->lock);
 671         for (i = 0; i < FUSE_PQ_HASH_SIZE; i++)
 672                 INIT_LIST_HEAD(&fpq->processing[i]);
 673         INIT_LIST_HEAD(&fpq->io);
 674         fpq->connected = 1;
 675 }
 676
 677 void fuse_conn_init(struct fuse_conn *fc, struct fuse_mount *fm,
 678                     struct user_namespace *user_ns,
 679                     const struct fuse_iqueue_ops *fiq_ops, void *fiq_priv)
 680 {
 681         memset(fc, 0, sizeof(*fc));
 682         spin_lock_init(&fc->lock);
 683         spin_lock_init(&fc->bg_lock);
 684         init_rwsem(&fc->killsb);
 685         refcount_set(&fc->count, 1);
 686         atomic_set(&fc->dev_count, 1);
 687         init_waitqueue_head(&fc->blocked_waitq);
 688         fuse_iqueue_init(&fc->iq, fiq_ops, fiq_priv);
 689         INIT_LIST_HEAD(&fc->bg_queue);
 690         INIT_LIST_HEAD(&fc->entry);
 691         INIT_LIST_HEAD(&fc->devices);
 692         atomic_set(&fc->num_waiting, 0);
 693         fc->max_background = FUSE_DEFAULT_MAX_BACKGROUND;
 694         fc->congestion_threshold = FUSE_DEFAULT_CONGESTION_THRESHOLD;
 695         atomic64_set(&fc->khctr, 0);
 696         fc->polled_files = RB_ROOT;
 697         fc->blocked = 0;
 698         fc->initialized = 0;
 699         fc->connected = 1;
 700         atomic64_set(&fc->attr_version, 1);
 701         get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key));
 702         fc->pid_ns = get_pid_ns(task_active_pid_ns(current));
 703         fc->user_ns = get_user_ns(user_ns);
 704         fc->max_pages = FUSE_DEFAULT_MAX_PAGES_PER_REQ;
 705
 706         INIT_LIST_HEAD(&fc->mounts);
 707         list_add(&fm->fc_entry, &fc->mounts);
 708         fm->fc = fc;
 709 }
 710 EXPORT_SYMBOL_GPL(fuse_conn_init);
 711
 712 void fuse_conn_put(struct fuse_conn *fc)
 713 {
 714         if (refcount_dec_and_test(&fc->count)) {
 715                 struct fuse_iqueue *fiq = &fc->iq;
 716
 717                 if (IS_ENABLED(CONFIG_FUSE_DAX))
 718                         fuse_dax_conn_free(fc);
 719                 if (fiq->ops->release)
 720                         fiq->ops->release(fiq);
 721                 put_pid_ns(fc->pid_ns);
 722                 put_user_ns(fc->user_ns);
 723                 fc->release(fc);
 724         }
 725 }
 726 EXPORT_SYMBOL_GPL(fuse_conn_put);
 727
 728 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc)
 729 {
 730         refcount_inc(&fc->count);
 731         return fc;
 732 }
 733 EXPORT_SYMBOL_GPL(fuse_conn_get);
 734
 735 static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned mode)
 736 {
 737         struct fuse_attr attr;
 738         memset(&attr, 0, sizeof(attr));
 739
 740         attr.mode = mode;
 741         attr.ino = FUSE_ROOT_ID;
 742         attr.nlink = 1;
 743         return fuse_iget(sb, 1, 0, &attr, 0, 0);
 744 }
 745
 746 struct fuse_inode_handle {
 747         u64 nodeid;
 748         u32 generation;
 749 };
 750
 751 static struct dentry *fuse_get_dentry(struct super_block *sb,
 752                                       struct fuse_inode_handle *handle)
 753 {
 754         struct fuse_conn *fc = get_fuse_conn_super(sb);
 755         struct inode *inode;
 756         struct dentry *entry;
 757         int err = -ESTALE;
 758
 759         if (handle->nodeid == 0)
 760                 goto out_err;
 761
 762         inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid);
 763         if (!inode) {
 764                 struct fuse_entry_out outarg;
 765                 const struct qstr name = QSTR_INIT(".", 1);
 766
 767                 if (!fc->export_support)
 768                         goto out_err;
 769
 770                 err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg,
 771                                        &inode);
 772                 if (err && err != -ENOENT)
 773                         goto out_err;
 774                 if (err || !inode) {
 775                         err = -ESTALE;
 776                         goto out_err;
 777                 }
 778                 err = -EIO;
 779                 if (get_node_id(inode) != handle->nodeid)
 780                         goto out_iput;
 781         }
 782         err = -ESTALE;
 783         if (inode->i_generation != handle->generation)
 784                 goto out_iput;
 785
 786         entry = d_obtain_alias(inode);
 787         if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID)
 788                 fuse_invalidate_entry_cache(entry);
 789
 790         return entry;
 791
 792  out_iput:
 793         iput(inode);
 794  out_err:
 795         return ERR_PTR(err);
 796 }
 797
 798 static int fuse_encode_fh(struct inode *inode, u32 *fh, int *max_len,
 799                            struct inode *parent)
 800 {
 801         int len = parent ? 6 : 3;
 802         u64 nodeid;
 803         u32 generation;
 804
 805         if (*max_len < len) {
 806                 *max_len = len;
 807                 return  FILEID_INVALID;
 808         }
 809
 810         nodeid = get_fuse_inode(inode)->nodeid;
 811         generation = inode->i_generation;
 812
 813         fh[0] = (u32)(nodeid >> 32);
 814         fh[1] = (u32)(nodeid & 0xffffffff);
 815         fh[2] = generation;
 816
 817         if (parent) {
 818                 nodeid = get_fuse_inode(parent)->nodeid;
 819                 generation = parent->i_generation;
 820
 821                 fh[3] = (u32)(nodeid >> 32);
 822                 fh[4] = (u32)(nodeid & 0xffffffff);
 823                 fh[5] = generation;
 824         }
 825
 826         *max_len = len;
 827         return parent ? 0x82 : 0x81;
 828 }
 829
 830 static struct dentry *fuse_fh_to_dentry(struct super_block *sb,
 831                 struct fid *fid, int fh_len, int fh_type)
 832 {
 833         struct fuse_inode_handle handle;
 834
 835         if ((fh_type != 0x81 && fh_type != 0x82) || fh_len < 3)
 836                 return NULL;
 837
 838         handle.nodeid = (u64) fid->raw[0] << 32;
 839         handle.nodeid |= (u64) fid->raw[1];
 840         handle.generation = fid->raw[2];
 841         return fuse_get_dentry(sb, &handle);
 842 }
 843
 844 static struct dentry *fuse_fh_to_parent(struct super_block *sb,
 845                 struct fid *fid, int fh_len, int fh_type)
 846 {
 847         struct fuse_inode_handle parent;
 848
 849         if (fh_type != 0x82 || fh_len < 6)
 850                 return NULL;
 851
 852         parent.nodeid = (u64) fid->raw[3] << 32;
 853         parent.nodeid |= (u64) fid->raw[4];
 854         parent.generation = fid->raw[5];
 855         return fuse_get_dentry(sb, &parent);
 856 }
 857
 858 static struct dentry *fuse_get_parent(struct dentry *child)
 859 {
 860         struct inode *child_inode = d_inode(child);
 861         struct fuse_conn *fc = get_fuse_conn(child_inode);
 862         struct inode *inode;
 863         struct dentry *parent;
 864         struct fuse_entry_out outarg;
 865         const struct qstr name = QSTR_INIT("..", 2);
 866         int err;
 867
 868         if (!fc->export_support)
 869                 return ERR_PTR(-ESTALE);
 870
 871         err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode),
 872                                &name, &outarg, &inode);
 873         if (err) {
 874                 if (err == -ENOENT)
 875                         return ERR_PTR(-ESTALE);
 876                 return ERR_PTR(err);
 877         }
 878
 879         parent = d_obtain_alias(inode);
 880         if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID)
 881                 fuse_invalidate_entry_cache(parent);
 882
 883         return parent;
 884 }
 885
 886 static const struct export_operations fuse_export_operations = {
 887         .fh_to_dentry   = fuse_fh_to_dentry,
 888         .fh_to_parent   = fuse_fh_to_parent,
 889         .encode_fh      = fuse_encode_fh,
 890         .get_parent     = fuse_get_parent,
 891 };
 892
 893 static const struct super_operations fuse_super_operations = {
 894         .alloc_inode    = fuse_alloc_inode,
 895         .free_inode     = fuse_free_inode,
 896         .evict_inode    = fuse_evict_inode,
 897         .write_inode    = fuse_write_inode,
 898         .drop_inode     = generic_delete_inode,
 899         .put_super      = fuse_put_super,
 900         .umount_begin   = fuse_umount_begin,
 901         .statfs         = fuse_statfs,
 902         .show_options   = fuse_show_options,
 903 };
 904
 905 static void sanitize_global_limit(unsigned *limit)
 906 {
 907         /*
 908          * The default maximum number of async requests is calculated to consume
 909          * 1/2^13 of the total memory, assuming 392 bytes per request.
 910          */
 911         if (*limit == 0)
 912                 *limit = ((totalram_pages() << PAGE_SHIFT) >> 13) / 392;
 913
 914         if (*limit >= 1 << 16)
 915                 *limit = (1 << 16) - 1;
 916 }
 917
 918 static int set_global_limit(const char *val, const struct kernel_param *kp)
 919 {
 920         int rv;
 921
 922         rv = param_set_uint(val, kp);
 923         if (rv)
 924                 return rv;
 925
 926         sanitize_global_limit((unsigned *)kp->arg);
 927
 928         return 0;
 929 }
 930
 931 static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg)
 932 {
 933         int cap_sys_admin = capable(CAP_SYS_ADMIN);
 934
 935         if (arg->minor < 13)
 936                 return;
 937
 938         sanitize_global_limit(&max_user_bgreq);
 939         sanitize_global_limit(&max_user_congthresh);
 940
 941         spin_lock(&fc->bg_lock);
 942         if (arg->max_background) {
 943                 fc->max_background = arg->max_background;
 944
 945                 if (!cap_sys_admin && fc->max_background > max_user_bgreq)
 946                         fc->max_background = max_user_bgreq;
 947         }
 948         if (arg->congestion_threshold) {
 949                 fc->congestion_threshold = arg->congestion_threshold;
 950
 951                 if (!cap_sys_admin &&
 952                     fc->congestion_threshold > max_user_congthresh)
 953                         fc->congestion_threshold = max_user_congthresh;
 954         }
 955         spin_unlock(&fc->bg_lock);
 956 }
 957
 958 struct fuse_init_args {
 959         struct fuse_args args;
 960         struct fuse_init_in in;
 961         struct fuse_init_out out;
 962 };
 963
 964 static void process_init_reply(struct fuse_mount *fm, struct fuse_args *args,
 965                                int error)
 966 {
 967         struct fuse_conn *fc = fm->fc;
 968         struct fuse_init_args *ia = container_of(args, typeof(*ia), args);
 969         struct fuse_init_out *arg = &ia->out;
 970         bool ok = true;
 971
 972         if (error || arg->major != FUSE_KERNEL_VERSION)
 973                 ok = false;
 974         else {
 975                 unsigned long ra_pages;
 976
 977                 process_init_limits(fc, arg);
 978
 979                 if (arg->minor >= 6) {
 980                         ra_pages = arg->max_readahead / PAGE_SIZE;
 981                         if (arg->flags & FUSE_ASYNC_READ)
 982                                 fc->async_read = 1;
 983                         if (!(arg->flags & FUSE_POSIX_LOCKS))
 984                                 fc->no_lock = 1;
 985                         if (arg->minor >= 17) {
 986                                 if (!(arg->flags & FUSE_FLOCK_LOCKS))
 987                                         fc->no_flock = 1;
 988                         } else {
 989                                 if (!(arg->flags & FUSE_POSIX_LOCKS))
 990                                         fc->no_flock = 1;
 991                         }
 992                         if (arg->flags & FUSE_ATOMIC_O_TRUNC)
 993                                 fc->atomic_o_trunc = 1;
 994                         if (arg->minor >= 9) {
 995                                 /* LOOKUP has dependency on proto version */
 996                                 if (arg->flags & FUSE_EXPORT_SUPPORT)
 997                                         fc->export_support = 1;
 998                         }
 999                         if (arg->flags & FUSE_BIG_WRITES)
1000                                 fc->big_writes = 1;
1001                         if (arg->flags & FUSE_DONT_MASK)
1002                                 fc->dont_mask = 1;
1003                         if (arg->flags & FUSE_AUTO_INVAL_DATA)
1004                                 fc->auto_inval_data = 1;
1005                         else if (arg->flags & FUSE_EXPLICIT_INVAL_DATA)
1006                                 fc->explicit_inval_data = 1;
1007                         if (arg->flags & FUSE_DO_READDIRPLUS) {
1008                                 fc->do_readdirplus = 1;
1009                                 if (arg->flags & FUSE_READDIRPLUS_AUTO)
1010                                         fc->readdirplus_auto = 1;
1011                         }
1012                         if (arg->flags & FUSE_ASYNC_DIO)
1013                                 fc->async_dio = 1;
1014                         if (arg->flags & FUSE_WRITEBACK_CACHE)
1015                                 fc->writeback_cache = 1;
1016                         if (arg->flags & FUSE_PARALLEL_DIROPS)
1017                                 fc->parallel_dirops = 1;
1018                         if (arg->flags & FUSE_HANDLE_KILLPRIV)
1019                                 fc->handle_killpriv = 1;
1020                         if (arg->time_gran && arg->time_gran <= 1000000000)
1021                                 fm->sb->s_time_gran = arg->time_gran;
1022                         if ((arg->flags & FUSE_POSIX_ACL)) {
1023                                 fc->default_permissions = 1;
1024                                 fc->posix_acl = 1;
1025                                 fm->sb->s_xattr = fuse_acl_xattr_handlers;
1026                         }
1027                         if (arg->flags & FUSE_CACHE_SYMLINKS)
1028                                 fc->cache_symlinks = 1;
1029                         if (arg->flags & FUSE_ABORT_ERROR)
1030                                 fc->abort_err = 1;
1031                         if (arg->flags & FUSE_MAX_PAGES) {
1032                                 fc->max_pages =
1033                                         min_t(unsigned int, FUSE_MAX_MAX_PAGES,
1034                                         max_t(unsigned int, arg->max_pages, 1));
1035                         }
1036                         if (IS_ENABLED(CONFIG_FUSE_DAX) &&
1037                             arg->flags & FUSE_MAP_ALIGNMENT &&
1038                             !fuse_dax_check_alignment(fc, arg->map_alignment)) {
1039                                 ok = false;
1040                         }
1041                 } else {
1042                         ra_pages = fc->max_read / PAGE_SIZE;
1043                         fc->no_lock = 1;
1044                         fc->no_flock = 1;
1045                 }
1046
1047                 fm->sb->s_bdi->ra_pages =
1048                                 min(fm->sb->s_bdi->ra_pages, ra_pages);
1049                 fc->minor = arg->minor;
1050                 fc->max_write = arg->minor < 5 ? 4096 : arg->max_write;
1051                 fc->max_write = max_t(unsigned, 4096, fc->max_write);
1052                 fc->conn_init = 1;
1053         }
1054         kfree(ia);
1055
1056         if (!ok) {
1057                 fc->conn_init = 0;
1058                 fc->conn_error = 1;
1059         }
1060
1061         fuse_set_initialized(fc);
1062         wake_up_all(&fc->blocked_waitq);
1063 }
1064
1065 void fuse_send_init(struct fuse_mount *fm)
1066 {
1067         struct fuse_init_args *ia;
1068
1069         ia = kzalloc(sizeof(*ia), GFP_KERNEL | __GFP_NOFAIL);
1070
1071         ia->in.major = FUSE_KERNEL_VERSION;
1072         ia->in.minor = FUSE_KERNEL_MINOR_VERSION;
1073         ia->in.max_readahead = fm->sb->s_bdi->ra_pages * PAGE_SIZE;
1074         ia->in.flags |=
1075                 FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC |
1076                 FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK |
1077                 FUSE_SPLICE_WRITE | FUSE_SPLICE_MOVE | FUSE_SPLICE_READ |
1078                 FUSE_FLOCK_LOCKS | FUSE_HAS_IOCTL_DIR | FUSE_AUTO_INVAL_DATA |
1079                 FUSE_DO_READDIRPLUS | FUSE_READDIRPLUS_AUTO | FUSE_ASYNC_DIO |
1080                 FUSE_WRITEBACK_CACHE | FUSE_NO_OPEN_SUPPORT |
1081                 FUSE_PARALLEL_DIROPS | FUSE_HANDLE_KILLPRIV | FUSE_POSIX_ACL |
1082                 FUSE_ABORT_ERROR | FUSE_MAX_PAGES | FUSE_CACHE_SYMLINKS |
1083                 FUSE_NO_OPENDIR_SUPPORT | FUSE_EXPLICIT_INVAL_DATA;
1084 #ifdef CONFIG_FUSE_DAX
1085         if (fm->fc->dax)
1086                 ia->in.flags |= FUSE_MAP_ALIGNMENT;
1087 #endif
1088         if (fm->fc->auto_submounts)
1089                 ia->in.flags |= FUSE_SUBMOUNTS;
1090
1091         ia->args.opcode = FUSE_INIT;
1092         ia->args.in_numargs = 1;
1093         ia->args.in_args[0].size = sizeof(ia->in);
1094         ia->args.in_args[0].value = &ia->in;
1095         ia->args.out_numargs = 1;
1096         /* Variable length argument used for backward compatibility
1097            with interface version < 7.5.  Rest of init_out is zeroed
1098            by do_get_request(), so a short reply is not a problem */
1099         ia->args.out_argvar = true;
1100         ia->args.out_args[0].size = sizeof(ia->out);
1101         ia->args.out_args[0].value = &ia->out;
1102         ia->args.force = true;
1103         ia->args.nocreds = true;
1104         ia->args.end = process_init_reply;
1105
1106         if (fuse_simple_background(fm, &ia->args, GFP_KERNEL) != 0)
1107                 process_init_reply(fm, &ia->args, -ENOTCONN);
1108 }
1109 EXPORT_SYMBOL_GPL(fuse_send_init);
1110
1111 void fuse_free_conn(struct fuse_conn *fc)
1112 {
1113         WARN_ON(!list_empty(&fc->devices));
1114         kfree_rcu(fc, rcu);
1115 }
1116 EXPORT_SYMBOL_GPL(fuse_free_conn);
1117
1118 static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
1119 {
1120         int err;
1121         char *suffix = "";
1122
1123         if (sb->s_bdev) {
1124                 suffix = "-fuseblk";
1125                 /*
1126                  * sb->s_bdi points to blkdev's bdi however we want to redirect
1127                  * it to our private bdi...
1128                  */
1129                 bdi_put(sb->s_bdi);
1130                 sb->s_bdi = &noop_backing_dev_info;
1131         }
1132         err = super_setup_bdi_name(sb, "%u:%u%s", MAJOR(fc->dev),
1133                                    MINOR(fc->dev), suffix);
1134         if (err)
1135                 return err;
1136
1137         /* fuse does it's own writeback accounting */
1138         sb->s_bdi->capabilities &= ~BDI_CAP_WRITEBACK_ACCT;
1139         sb->s_bdi->capabilities |= BDI_CAP_STRICTLIMIT;
1140
1141         /*
1142          * For a single fuse filesystem use max 1% of dirty +
1143          * writeback threshold.
1144          *
1145          * This gives about 1M of write buffer for memory maps on a
1146          * machine with 1G and 10% dirty_ratio, which should be more
1147          * than enough.
1148          *
1149          * Privileged users can raise it by writing to
1150          *
1151          *    /sys/class/bdi/<bdi>/max_ratio
1152          */
1153         bdi_set_max_ratio(sb->s_bdi, 1);
1154
1155         return 0;
1156 }
1157
1158 struct fuse_dev *fuse_dev_alloc(void)
1159 {
1160         struct fuse_dev *fud;
1161         struct list_head *pq;
1162
1163         fud = kzalloc(sizeof(struct fuse_dev), GFP_KERNEL);
1164         if (!fud)
1165                 return NULL;
1166
1167         pq = kcalloc(FUSE_PQ_HASH_SIZE, sizeof(struct list_head), GFP_KERNEL);
1168         if (!pq) {
1169                 kfree(fud);
1170                 return NULL;
1171         }
1172
1173         fud->pq.processing = pq;
1174         fuse_pqueue_init(&fud->pq);
1175
1176         return fud;
1177 }
1178 EXPORT_SYMBOL_GPL(fuse_dev_alloc);
1179
1180 void fuse_dev_install(struct fuse_dev *fud, struct fuse_conn *fc)
1181 {
1182         fud->fc = fuse_conn_get(fc);
1183         spin_lock(&fc->lock);
1184         list_add_tail(&fud->entry, &fc->devices);
1185         spin_unlock(&fc->lock);
1186 }
1187 EXPORT_SYMBOL_GPL(fuse_dev_install);
1188
1189 struct fuse_dev *fuse_dev_alloc_install(struct fuse_conn *fc)
1190 {
1191         struct fuse_dev *fud;
1192
1193         fud = fuse_dev_alloc();
1194         if (!fud)
1195                 return NULL;
1196
1197         fuse_dev_install(fud, fc);
1198         return fud;
1199 }
1200 EXPORT_SYMBOL_GPL(fuse_dev_alloc_install);
1201
1202 void fuse_dev_free(struct fuse_dev *fud)
1203 {
1204         struct fuse_conn *fc = fud->fc;
1205
1206         if (fc) {
1207                 spin_lock(&fc->lock);
1208                 list_del(&fud->entry);
1209                 spin_unlock(&fc->lock);
1210
1211                 fuse_conn_put(fc);
1212         }
1213         kfree(fud->pq.processing);
1214         kfree(fud);
1215 }
1216 EXPORT_SYMBOL_GPL(fuse_dev_free);
1217
1218 static void fuse_fill_attr_from_inode(struct fuse_attr *attr,
1219                                       const struct fuse_inode *fi)
1220 {
1221         *attr = (struct fuse_attr){
1222                 .ino            = fi->inode.i_ino,
1223                 .size           = fi->inode.i_size,
1224                 .blocks         = fi->inode.i_blocks,
1225                 .atime          = fi->inode.i_atime.tv_sec,
1226                 .mtime          = fi->inode.i_mtime.tv_sec,
1227                 .ctime          = fi->inode.i_ctime.tv_sec,
1228                 .atimensec      = fi->inode.i_atime.tv_nsec,
1229                 .mtimensec      = fi->inode.i_mtime.tv_nsec,
1230                 .ctimensec      = fi->inode.i_ctime.tv_nsec,
1231                 .mode           = fi->inode.i_mode,
1232                 .nlink          = fi->inode.i_nlink,
1233                 .uid            = fi->inode.i_uid.val,
1234                 .gid            = fi->inode.i_gid.val,
1235                 .rdev           = fi->inode.i_rdev,
1236                 .blksize        = 1u << fi->inode.i_blkbits,
1237         };
1238 }
1239
1240 static void fuse_sb_defaults(struct super_block *sb)
1241 {
1242         sb->s_magic = FUSE_SUPER_MAGIC;
1243         sb->s_op = &fuse_super_operations;
1244         sb->s_xattr = fuse_xattr_handlers;
1245         sb->s_maxbytes = MAX_LFS_FILESIZE;
1246         sb->s_time_gran = 1;
1247         sb->s_export_op = &fuse_export_operations;
1248         sb->s_iflags |= SB_I_IMA_UNVERIFIABLE_SIGNATURE;
1249         if (sb->s_user_ns != &init_user_ns)
1250                 sb->s_iflags |= SB_I_UNTRUSTED_MOUNTER;
1251         sb->s_flags &= ~(SB_NOSEC | SB_I_VERSION);
1252
1253         /*
1254          * If we are not in the initial user namespace posix
1255          * acls must be translated.
1256          */
1257         if (sb->s_user_ns != &init_user_ns)
1258                 sb->s_xattr = fuse_no_acl_xattr_handlers;
1259 }
1260
1261 int fuse_fill_super_submount(struct super_block *sb,
1262                              struct fuse_inode *parent_fi)
1263 {
1264         struct fuse_mount *fm = get_fuse_mount_super(sb);
1265         struct super_block *parent_sb = parent_fi->inode.i_sb;
1266         struct fuse_attr root_attr;
1267         struct inode *root;
1268
1269         fuse_sb_defaults(sb);
1270         fm->sb = sb;
1271
1272         WARN_ON(sb->s_bdi != &noop_backing_dev_info);
1273         sb->s_bdi = bdi_get(parent_sb->s_bdi);
1274
1275         sb->s_xattr = parent_sb->s_xattr;
1276         sb->s_time_gran = parent_sb->s_time_gran;
1277         sb->s_blocksize = parent_sb->s_blocksize;
1278         sb->s_blocksize_bits = parent_sb->s_blocksize_bits;
1279         sb->s_subtype = kstrdup(parent_sb->s_subtype, GFP_KERNEL);
1280         if (parent_sb->s_subtype && !sb->s_subtype)
1281                 return -ENOMEM;
1282
1283         fuse_fill_attr_from_inode(&root_attr, parent_fi);
1284         root = fuse_iget(sb, parent_fi->nodeid, 0, &root_attr, 0, 0);
1285         /*
1286          * This inode is just a duplicate, so it is not looked up and
1287          * its nlookup should not be incremented.  fuse_iget() does
1288          * that, though, so undo it here.
1289          */
1290         get_fuse_inode(root)->nlookup--;
1291         sb->s_d_op = &fuse_dentry_operations;
1292         sb->s_root = d_make_root(root);
1293         if (!sb->s_root)
1294                 return -ENOMEM;
1295
1296         return 0;
1297 }
1298
1299 int fuse_fill_super_common(struct super_block *sb, struct fuse_fs_context *ctx)
1300 {
1301         struct fuse_dev *fud = NULL;
1302         struct fuse_mount *fm = get_fuse_mount_super(sb);
1303         struct fuse_conn *fc = fm->fc;
1304         struct inode *root;
1305         struct dentry *root_dentry;
1306         int err;
1307
1308         err = -EINVAL;
1309         if (sb->s_flags & SB_MANDLOCK)
1310                 goto err;
1311
1312         fuse_sb_defaults(sb);
1313
1314         if (ctx->is_bdev) {
1315 #ifdef CONFIG_BLOCK
1316                 err = -EINVAL;
1317                 if (!sb_set_blocksize(sb, ctx->blksize))
1318                         goto err;
1319 #endif
1320         } else {
1321                 sb->s_blocksize = PAGE_SIZE;
1322                 sb->s_blocksize_bits = PAGE_SHIFT;
1323         }
1324
1325         sb->s_subtype = ctx->subtype;
1326         ctx->subtype = NULL;
1327         if (IS_ENABLED(CONFIG_FUSE_DAX)) {
1328                 err = fuse_dax_conn_alloc(fc, ctx->dax_dev);
1329                 if (err)
1330                         goto err;
1331         }
1332
1333         if (ctx->fudptr) {
1334                 err = -ENOMEM;
1335                 fud = fuse_dev_alloc_install(fc);
1336                 if (!fud)
1337                         goto err_free_dax;
1338         }
1339
1340         fc->dev = sb->s_dev;
1341         fm->sb = sb;
1342         err = fuse_bdi_init(fc, sb);
1343         if (err)
1344                 goto err_dev_free;
1345
1346         /* Handle umasking inside the fuse code */
1347         if (sb->s_flags & SB_POSIXACL)
1348                 fc->dont_mask = 1;
1349         sb->s_flags |= SB_POSIXACL;
1350
1351         fc->default_permissions = ctx->default_permissions;
1352         fc->allow_other = ctx->allow_other;
1353         fc->user_id = ctx->user_id;
1354         fc->group_id = ctx->group_id;
1355         fc->legacy_opts_show = ctx->legacy_opts_show;
1356         fc->max_read = max_t(unsigned int, 4096, ctx->max_read);
1357         fc->destroy = ctx->destroy;
1358         fc->no_control = ctx->no_control;
1359         fc->no_force_umount = ctx->no_force_umount;
1360
1361         err = -ENOMEM;
1362         root = fuse_get_root_inode(sb, ctx->rootmode);
1363         sb->s_d_op = &fuse_root_dentry_operations;
1364         root_dentry = d_make_root(root);
1365         if (!root_dentry)
1366                 goto err_dev_free;
1367         /* Root dentry doesn't have .d_revalidate */
1368         sb->s_d_op = &fuse_dentry_operations;
1369
1370         mutex_lock(&fuse_mutex);
1371         err = -EINVAL;
1372         if (ctx->fudptr && *ctx->fudptr)
1373                 goto err_unlock;
1374
1375         err = fuse_ctl_add_conn(fc);
1376         if (err)
1377                 goto err_unlock;
1378
1379         list_add_tail(&fc->entry, &fuse_conn_list);
1380         sb->s_root = root_dentry;
1381         if (ctx->fudptr)
1382                 *ctx->fudptr = fud;
1383         mutex_unlock(&fuse_mutex);
1384         return 0;
1385
1386  err_unlock:
1387         mutex_unlock(&fuse_mutex);
1388         dput(root_dentry);
1389  err_dev_free:
1390         if (fud)
1391                 fuse_dev_free(fud);
1392  err_free_dax:
1393         if (IS_ENABLED(CONFIG_FUSE_DAX))
1394                 fuse_dax_conn_free(fc);
1395  err:
1396         return err;
1397 }
1398 EXPORT_SYMBOL_GPL(fuse_fill_super_common);
1399
1400 static int fuse_fill_super(struct super_block *sb, struct fs_context *fsc)
1401 {
1402         struct fuse_fs_context *ctx = fsc->fs_private;
1403         struct file *file;
1404         int err;
1405         struct fuse_conn *fc;
1406         struct fuse_mount *fm;
1407
1408         err = -EINVAL;
1409         file = fget(ctx->fd);
1410         if (!file)
1411                 goto err;
1412
1413         /*
1414          * Require mount to happen from the same user namespace which
1415          * opened /dev/fuse to prevent potential attacks.
1416          */
1417         if ((file->f_op != &fuse_dev_operations) ||
1418             (file->f_cred->user_ns != sb->s_user_ns))
1419                 goto err_fput;
1420         ctx->fudptr = &file->private_data;
1421
1422         fc = kmalloc(sizeof(*fc), GFP_KERNEL);
1423         err = -ENOMEM;
1424         if (!fc)
1425                 goto err_fput;
1426
1427         fm = kzalloc(sizeof(*fm), GFP_KERNEL);
1428         if (!fm) {
1429                 kfree(fc);
1430                 goto err_fput;
1431         }
1432
1433         fuse_conn_init(fc, fm, sb->s_user_ns, &fuse_dev_fiq_ops, NULL);
1434         fc->release = fuse_free_conn;
1435
1436         sb->s_fs_info = fm;
1437
1438         err = fuse_fill_super_common(sb, ctx);
1439         if (err)
1440                 goto err_put_conn;
1441         /*
1442          * atomic_dec_and_test() in fput() provides the necessary
1443          * memory barrier for file->private_data to be visible on all
1444          * CPUs after this
1445          */
1446         fput(file);
1447         fuse_send_init(get_fuse_mount_super(sb));
1448         return 0;
1449
1450  err_put_conn:
1451         fuse_conn_put(fc);
1452         kfree(fm);
1453         sb->s_fs_info = NULL;
1454  err_fput:
1455         fput(file);
1456  err:
1457         return err;
1458 }
1459
1460 static int fuse_get_tree(struct fs_context *fc)
1461 {
1462         struct fuse_fs_context *ctx = fc->fs_private;
1463
1464         if (!ctx->fd_present || !ctx->rootmode_present ||
1465             !ctx->user_id_present || !ctx->group_id_present)
1466                 return -EINVAL;
1467
1468 #ifdef CONFIG_BLOCK
1469         if (ctx->is_bdev)
1470                 return get_tree_bdev(fc, fuse_fill_super);
1471 #endif
1472
1473         return get_tree_nodev(fc, fuse_fill_super);
1474 }
1475
1476 static const struct fs_context_operations fuse_context_ops = {
1477         .free           = fuse_free_fc,
1478         .parse_param    = fuse_parse_param,
1479         .reconfigure    = fuse_reconfigure,
1480         .get_tree       = fuse_get_tree,
1481 };
1482
1483 /*
1484  * Set up the filesystem mount context.
1485  */
1486 static int fuse_init_fs_context(struct fs_context *fc)
1487 {
1488         struct fuse_fs_context *ctx;
1489
1490         ctx = kzalloc(sizeof(struct fuse_fs_context), GFP_KERNEL);
1491         if (!ctx)
1492                 return -ENOMEM;
1493
1494         ctx->max_read = ~0;
1495         ctx->blksize = FUSE_DEFAULT_BLKSIZE;
1496         ctx->legacy_opts_show = true;
1497
1498 #ifdef CONFIG_BLOCK
1499         if (fc->fs_type == &fuseblk_fs_type) {
1500                 ctx->is_bdev = true;
1501                 ctx->destroy = true;
1502         }
1503 #endif
1504
1505         fc->fs_private = ctx;
1506         fc->ops = &fuse_context_ops;
1507         return 0;
1508 }
1509
1510 bool fuse_mount_remove(struct fuse_mount *fm)
1511 {
1512         struct fuse_conn *fc = fm->fc;
1513         bool last = false;
1514
1515         down_write(&fc->killsb);
1516         list_del_init(&fm->fc_entry);
1517         if (list_empty(&fc->mounts))
1518                 last = true;
1519         up_write(&fc->killsb);
1520
1521         return last;
1522 }
1523 EXPORT_SYMBOL_GPL(fuse_mount_remove);
1524
1525 void fuse_conn_destroy(struct fuse_mount *fm)
1526 {
1527         struct fuse_conn *fc = fm->fc;
1528
1529         if (fc->destroy)
1530                 fuse_send_destroy(fm);
1531
1532         fuse_abort_conn(fc);
1533         fuse_wait_aborted(fc);
1534
1535         if (!list_empty(&fc->entry)) {
1536                 mutex_lock(&fuse_mutex);
1537                 list_del(&fc->entry);
1538                 fuse_ctl_remove_conn(fc);
1539                 mutex_unlock(&fuse_mutex);
1540         }
1541 }
1542 EXPORT_SYMBOL_GPL(fuse_conn_destroy);
1543
1544 static void fuse_sb_destroy(struct super_block *sb)
1545 {
1546         struct fuse_mount *fm = get_fuse_mount_super(sb);
1547         bool last;
1548
1549         if (fm) {
1550                 last = fuse_mount_remove(fm);
1551                 if (last)
1552                         fuse_conn_destroy(fm);
1553         }
1554 }
1555
1556 static void fuse_kill_sb_anon(struct super_block *sb)
1557 {
1558         fuse_sb_destroy(sb);
1559         kill_anon_super(sb);
1560 }
1561
1562 static struct file_system_type fuse_fs_type = {
1563         .owner          = THIS_MODULE,
1564         .name           = "fuse",
1565         .fs_flags       = FS_HAS_SUBTYPE | FS_USERNS_MOUNT,
1566         .init_fs_context = fuse_init_fs_context,
1567         .parameters     = fuse_fs_parameters,
1568         .kill_sb        = fuse_kill_sb_anon,
1569 };
1570 MODULE_ALIAS_FS("fuse");
1571
1572 #ifdef CONFIG_BLOCK
1573 static void fuse_kill_sb_blk(struct super_block *sb)
1574 {
1575         fuse_sb_destroy(sb);
1576         kill_block_super(sb);
1577 }
1578
1579 static struct file_system_type fuseblk_fs_type = {
1580         .owner          = THIS_MODULE,
1581         .name           = "fuseblk",
1582         .init_fs_context = fuse_init_fs_context,
1583         .parameters     = fuse_fs_parameters,
1584         .kill_sb        = fuse_kill_sb_blk,
1585         .fs_flags       = FS_REQUIRES_DEV | FS_HAS_SUBTYPE,
1586 };
1587 MODULE_ALIAS_FS("fuseblk");
1588
1589 static inline int register_fuseblk(void)
1590 {
1591         return register_filesystem(&fuseblk_fs_type);
1592 }
1593
1594 static inline void unregister_fuseblk(void)
1595 {
1596         unregister_filesystem(&fuseblk_fs_type);
1597 }
1598 #else
1599 static inline int register_fuseblk(void)
1600 {
1601         return 0;
1602 }
1603
1604 static inline void unregister_fuseblk(void)
1605 {
1606 }
1607 #endif
1608
1609 static void fuse_inode_init_once(void *foo)
1610 {
1611         struct inode *inode = foo;
1612
1613         inode_init_once(inode);
1614 }
1615
1616 static int __init fuse_fs_init(void)
1617 {
1618         int err;
1619
1620         fuse_inode_cachep = kmem_cache_create("fuse_inode",
1621                         sizeof(struct fuse_inode), 0,
1622                         SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT|SLAB_RECLAIM_ACCOUNT,
1623                         fuse_inode_init_once);
1624         err = -ENOMEM;
1625         if (!fuse_inode_cachep)
1626                 goto out;
1627
1628         err = register_fuseblk();
1629         if (err)
1630                 goto out2;
1631
1632         err = register_filesystem(&fuse_fs_type);
1633         if (err)
1634                 goto out3;
1635
1636         return 0;
1637
1638  out3:
1639         unregister_fuseblk();
1640  out2:
1641         kmem_cache_destroy(fuse_inode_cachep);
1642  out:
1643         return err;
1644 }
1645
1646 static void fuse_fs_cleanup(void)
1647 {
1648         unregister_filesystem(&fuse_fs_type);
1649         unregister_fuseblk();
1650
1651         /*
1652          * Make sure all delayed rcu free inodes are flushed before we
1653          * destroy cache.
1654          */
1655         rcu_barrier();
1656         kmem_cache_destroy(fuse_inode_cachep);
1657 }
1658
1659 static struct kobject *fuse_kobj;
1660
1661 static int fuse_sysfs_init(void)
1662 {
1663         int err;
1664
1665         fuse_kobj = kobject_create_and_add("fuse", fs_kobj);
1666         if (!fuse_kobj) {
1667                 err = -ENOMEM;
1668                 goto out_err;
1669         }
1670
1671         err = sysfs_create_mount_point(fuse_kobj, "connections");
1672         if (err)
1673                 goto out_fuse_unregister;
1674
1675         return 0;
1676
1677  out_fuse_unregister:
1678         kobject_put(fuse_kobj);
1679  out_err:
1680         return err;
1681 }
1682
1683 static void fuse_sysfs_cleanup(void)
1684 {
1685         sysfs_remove_mount_point(fuse_kobj, "connections");
1686         kobject_put(fuse_kobj);
1687 }
1688
1689 static int __init fuse_init(void)
1690 {
1691         int res;
1692
1693         pr_info("init (API version %i.%i)\n",
1694                 FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);
1695
1696         INIT_LIST_HEAD(&fuse_conn_list);
1697         res = fuse_fs_init();
1698         if (res)
1699                 goto err;
1700
1701         res = fuse_dev_init();
1702         if (res)
1703                 goto err_fs_cleanup;
1704
1705         res = fuse_sysfs_init();
1706         if (res)
1707                 goto err_dev_cleanup;
1708
1709         res = fuse_ctl_init();
1710         if (res)
1711                 goto err_sysfs_cleanup;
1712
1713         sanitize_global_limit(&max_user_bgreq);
1714         sanitize_global_limit(&max_user_congthresh);
1715
1716         return 0;
1717
1718  err_sysfs_cleanup:
1719         fuse_sysfs_cleanup();
1720  err_dev_cleanup:
1721         fuse_dev_cleanup();
1722  err_fs_cleanup:
1723         fuse_fs_cleanup();
1724  err:
1725         return res;
1726 }
1727
1728 static void __exit fuse_exit(void)
1729 {
1730         pr_debug("exit\n");
1731
1732         fuse_ctl_cleanup();
1733         fuse_sysfs_cleanup();
1734         fuse_fs_cleanup();
1735         fuse_dev_cleanup();
1736 }
1737
1738 module_init(fuse_init);
1739 module_exit(fuse_exit);