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