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 spin_unlock(&fc->lock); 206 return; 207 } 208 209 old_mtime = inode->i_mtime; 210 fuse_change_attributes_common(inode, attr, attr_valid); 211 212 oldsize = inode->i_size; 213 i_size_write(inode, attr->size); 214 spin_unlock(&fc->lock); 215 216 if (S_ISREG(inode->i_mode)) { 217 bool inval = false; 218 219 if (oldsize != attr->size) { 220 truncate_pagecache(inode, oldsize, attr->size); 221 inval = true; 222 } else if (fc->auto_inval_data) { 223 struct timespec new_mtime = { 224 .tv_sec = attr->mtime, 225 .tv_nsec = attr->mtimensec, 226 }; 227 228 /* 229 * Auto inval mode also checks and invalidates if mtime 230 * has changed. 231 */ 232 if (!timespec_equal(&old_mtime, &new_mtime)) 233 inval = true; 234 } 235 236 if (inval) 237 invalidate_inode_pages2(inode->i_mapping); 238 } 239 } 240 241 static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr) 242 { 243 inode->i_mode = attr->mode & S_IFMT; 244 inode->i_size = attr->size; 245 if (S_ISREG(inode->i_mode)) { 246 fuse_init_common(inode); 247 fuse_init_file_inode(inode); 248 } else if (S_ISDIR(inode->i_mode)) 249 fuse_init_dir(inode); 250 else if (S_ISLNK(inode->i_mode)) 251 fuse_init_symlink(inode); 252 else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) || 253 S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) { 254 fuse_init_common(inode); 255 init_special_inode(inode, inode->i_mode, 256 new_decode_dev(attr->rdev)); 257 } else 258 BUG(); 259 } 260 261 int fuse_inode_eq(struct inode *inode, void *_nodeidp) 262 { 263 u64 nodeid = *(u64 *) _nodeidp; 264 if (get_node_id(inode) == nodeid) 265 return 1; 266 else 267 return 0; 268 } 269 270 static int fuse_inode_set(struct inode *inode, void *_nodeidp) 271 { 272 u64 nodeid = *(u64 *) _nodeidp; 273 get_fuse_inode(inode)->nodeid = nodeid; 274 return 0; 275 } 276 277 struct inode *fuse_iget(struct super_block *sb, u64 nodeid, 278 int generation, struct fuse_attr *attr, 279 u64 attr_valid, u64 attr_version) 280 { 281 struct inode *inode; 282 struct fuse_inode *fi; 283 struct fuse_conn *fc = get_fuse_conn_super(sb); 284 285 retry: 286 inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid); 287 if (!inode) 288 return NULL; 289 290 if ((inode->i_state & I_NEW)) { 291 inode->i_flags |= S_NOATIME|S_NOCMTIME; 292 inode->i_generation = generation; 293 inode->i_data.backing_dev_info = &fc->bdi; 294 fuse_init_inode(inode, attr); 295 unlock_new_inode(inode); 296 } else if ((inode->i_mode ^ attr->mode) & S_IFMT) { 297 /* Inode has changed type, any I/O on the old should fail */ 298 make_bad_inode(inode); 299 iput(inode); 300 goto retry; 301 } 302 303 fi = get_fuse_inode(inode); 304 spin_lock(&fc->lock); 305 fi->nlookup++; 306 spin_unlock(&fc->lock); 307 fuse_change_attributes(inode, attr, attr_valid, attr_version); 308 309 return inode; 310 } 311 312 int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid, 313 loff_t offset, loff_t len) 314 { 315 struct inode *inode; 316 pgoff_t pg_start; 317 pgoff_t pg_end; 318 319 inode = ilookup5(sb, nodeid, fuse_inode_eq, &nodeid); 320 if (!inode) 321 return -ENOENT; 322 323 fuse_invalidate_attr(inode); 324 if (offset >= 0) { 325 pg_start = offset >> PAGE_CACHE_SHIFT; 326 if (len <= 0) 327 pg_end = -1; 328 else 329 pg_end = (offset + len - 1) >> PAGE_CACHE_SHIFT; 330 invalidate_inode_pages2_range(inode->i_mapping, 331 pg_start, pg_end); 332 } 333 iput(inode); 334 return 0; 335 } 336 337 static void fuse_umount_begin(struct super_block *sb) 338 { 339 fuse_abort_conn(get_fuse_conn_super(sb)); 340 } 341 342 static void fuse_send_destroy(struct fuse_conn *fc) 343 { 344 struct fuse_req *req = fc->destroy_req; 345 if (req && fc->conn_init) { 346 fc->destroy_req = NULL; 347 req->in.h.opcode = FUSE_DESTROY; 348 req->force = 1; 349 req->background = 0; 350 fuse_request_send(fc, req); 351 fuse_put_request(fc, req); 352 } 353 } 354 355 static void fuse_bdi_destroy(struct fuse_conn *fc) 356 { 357 if (fc->bdi_initialized) 358 bdi_destroy(&fc->bdi); 359 } 360 361 void fuse_conn_kill(struct fuse_conn *fc) 362 { 363 spin_lock(&fc->lock); 364 fc->connected = 0; 365 fc->blocked = 0; 366 fc->initialized = 1; 367 spin_unlock(&fc->lock); 368 /* Flush all readers on this fs */ 369 kill_fasync(&fc->fasync, SIGIO, POLL_IN); 370 wake_up_all(&fc->waitq); 371 wake_up_all(&fc->blocked_waitq); 372 wake_up_all(&fc->reserved_req_waitq); 373 } 374 EXPORT_SYMBOL_GPL(fuse_conn_kill); 375 376 static void fuse_put_super(struct super_block *sb) 377 { 378 struct fuse_conn *fc = get_fuse_conn_super(sb); 379 380 fuse_send_destroy(fc); 381 382 fuse_conn_kill(fc); 383 mutex_lock(&fuse_mutex); 384 list_del(&fc->entry); 385 fuse_ctl_remove_conn(fc); 386 mutex_unlock(&fuse_mutex); 387 fuse_bdi_destroy(fc); 388 389 fuse_conn_put(fc); 390 } 391 392 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr) 393 { 394 stbuf->f_type = FUSE_SUPER_MAGIC; 395 stbuf->f_bsize = attr->bsize; 396 stbuf->f_frsize = attr->frsize; 397 stbuf->f_blocks = attr->blocks; 398 stbuf->f_bfree = attr->bfree; 399 stbuf->f_bavail = attr->bavail; 400 stbuf->f_files = attr->files; 401 stbuf->f_ffree = attr->ffree; 402 stbuf->f_namelen = attr->namelen; 403 /* fsid is left zero */ 404 } 405 406 static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf) 407 { 408 struct super_block *sb = dentry->d_sb; 409 struct fuse_conn *fc = get_fuse_conn_super(sb); 410 struct fuse_req *req; 411 struct fuse_statfs_out outarg; 412 int err; 413 414 if (!fuse_allow_current_process(fc)) { 415 buf->f_type = FUSE_SUPER_MAGIC; 416 return 0; 417 } 418 419 req = fuse_get_req_nopages(fc); 420 if (IS_ERR(req)) 421 return PTR_ERR(req); 422 423 memset(&outarg, 0, sizeof(outarg)); 424 req->in.numargs = 0; 425 req->in.h.opcode = FUSE_STATFS; 426 req->in.h.nodeid = get_node_id(dentry->d_inode); 427 req->out.numargs = 1; 428 req->out.args[0].size = 429 fc->minor < 4 ? FUSE_COMPAT_STATFS_SIZE : sizeof(outarg); 430 req->out.args[0].value = &outarg; 431 fuse_request_send(fc, req); 432 err = req->out.h.error; 433 if (!err) 434 convert_fuse_statfs(buf, &outarg.st); 435 fuse_put_request(fc, req); 436 return err; 437 } 438 439 enum { 440 OPT_FD, 441 OPT_ROOTMODE, 442 OPT_USER_ID, 443 OPT_GROUP_ID, 444 OPT_DEFAULT_PERMISSIONS, 445 OPT_ALLOW_OTHER, 446 OPT_MAX_READ, 447 OPT_BLKSIZE, 448 OPT_ERR 449 }; 450 451 static const match_table_t tokens = { 452 {OPT_FD, "fd=%u"}, 453 {OPT_ROOTMODE, "rootmode=%o"}, 454 {OPT_USER_ID, "user_id=%u"}, 455 {OPT_GROUP_ID, "group_id=%u"}, 456 {OPT_DEFAULT_PERMISSIONS, "default_permissions"}, 457 {OPT_ALLOW_OTHER, "allow_other"}, 458 {OPT_MAX_READ, "max_read=%u"}, 459 {OPT_BLKSIZE, "blksize=%u"}, 460 {OPT_ERR, NULL} 461 }; 462 463 static int parse_fuse_opt(char *opt, struct fuse_mount_data *d, int is_bdev) 464 { 465 char *p; 466 memset(d, 0, sizeof(struct fuse_mount_data)); 467 d->max_read = ~0; 468 d->blksize = FUSE_DEFAULT_BLKSIZE; 469 470 while ((p = strsep(&opt, ",")) != NULL) { 471 int token; 472 int value; 473 substring_t args[MAX_OPT_ARGS]; 474 if (!*p) 475 continue; 476 477 token = match_token(p, tokens, args); 478 switch (token) { 479 case OPT_FD: 480 if (match_int(&args[0], &value)) 481 return 0; 482 d->fd = value; 483 d->fd_present = 1; 484 break; 485 486 case OPT_ROOTMODE: 487 if (match_octal(&args[0], &value)) 488 return 0; 489 if (!fuse_valid_type(value)) 490 return 0; 491 d->rootmode = value; 492 d->rootmode_present = 1; 493 break; 494 495 case OPT_USER_ID: 496 if (match_int(&args[0], &value)) 497 return 0; 498 d->user_id = make_kuid(current_user_ns(), value); 499 if (!uid_valid(d->user_id)) 500 return 0; 501 d->user_id_present = 1; 502 break; 503 504 case OPT_GROUP_ID: 505 if (match_int(&args[0], &value)) 506 return 0; 507 d->group_id = make_kgid(current_user_ns(), value); 508 if (!gid_valid(d->group_id)) 509 return 0; 510 d->group_id_present = 1; 511 break; 512 513 case OPT_DEFAULT_PERMISSIONS: 514 d->flags |= FUSE_DEFAULT_PERMISSIONS; 515 break; 516 517 case OPT_ALLOW_OTHER: 518 d->flags |= FUSE_ALLOW_OTHER; 519 break; 520 521 case OPT_MAX_READ: 522 if (match_int(&args[0], &value)) 523 return 0; 524 d->max_read = value; 525 break; 526 527 case OPT_BLKSIZE: 528 if (!is_bdev || match_int(&args[0], &value)) 529 return 0; 530 d->blksize = value; 531 break; 532 533 default: 534 return 0; 535 } 536 } 537 538 if (!d->fd_present || !d->rootmode_present || 539 !d->user_id_present || !d->group_id_present) 540 return 0; 541 542 return 1; 543 } 544 545 static int fuse_show_options(struct seq_file *m, struct dentry *root) 546 { 547 struct super_block *sb = root->d_sb; 548 struct fuse_conn *fc = get_fuse_conn_super(sb); 549 550 seq_printf(m, ",user_id=%u", from_kuid_munged(&init_user_ns, fc->user_id)); 551 seq_printf(m, ",group_id=%u", from_kgid_munged(&init_user_ns, fc->group_id)); 552 if (fc->flags & FUSE_DEFAULT_PERMISSIONS) 553 seq_puts(m, ",default_permissions"); 554 if (fc->flags & FUSE_ALLOW_OTHER) 555 seq_puts(m, ",allow_other"); 556 if (fc->max_read != ~0) 557 seq_printf(m, ",max_read=%u", fc->max_read); 558 if (sb->s_bdev && sb->s_blocksize != FUSE_DEFAULT_BLKSIZE) 559 seq_printf(m, ",blksize=%lu", sb->s_blocksize); 560 return 0; 561 } 562 563 void fuse_conn_init(struct fuse_conn *fc) 564 { 565 memset(fc, 0, sizeof(*fc)); 566 spin_lock_init(&fc->lock); 567 mutex_init(&fc->inst_mutex); 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 mutex_destroy(&fc->inst_mutex); 599 fc->release(fc); 600 } 601 } 602 EXPORT_SYMBOL_GPL(fuse_conn_put); 603 604 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc) 605 { 606 atomic_inc(&fc->count); 607 return fc; 608 } 609 EXPORT_SYMBOL_GPL(fuse_conn_get); 610 611 static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned mode) 612 { 613 struct fuse_attr attr; 614 memset(&attr, 0, sizeof(attr)); 615 616 attr.mode = mode; 617 attr.ino = FUSE_ROOT_ID; 618 attr.nlink = 1; 619 return fuse_iget(sb, 1, 0, &attr, 0, 0); 620 } 621 622 struct fuse_inode_handle { 623 u64 nodeid; 624 u32 generation; 625 }; 626 627 static struct dentry *fuse_get_dentry(struct super_block *sb, 628 struct fuse_inode_handle *handle) 629 { 630 struct fuse_conn *fc = get_fuse_conn_super(sb); 631 struct inode *inode; 632 struct dentry *entry; 633 int err = -ESTALE; 634 635 if (handle->nodeid == 0) 636 goto out_err; 637 638 inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid); 639 if (!inode) { 640 struct fuse_entry_out outarg; 641 struct qstr name; 642 643 if (!fc->export_support) 644 goto out_err; 645 646 name.len = 1; 647 name.name = "."; 648 err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg, 649 &inode); 650 if (err && err != -ENOENT) 651 goto out_err; 652 if (err || !inode) { 653 err = -ESTALE; 654 goto out_err; 655 } 656 err = -EIO; 657 if (get_node_id(inode) != handle->nodeid) 658 goto out_iput; 659 } 660 err = -ESTALE; 661 if (inode->i_generation != handle->generation) 662 goto out_iput; 663 664 entry = d_obtain_alias(inode); 665 if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID) 666 fuse_invalidate_entry_cache(entry); 667 668 return entry; 669 670 out_iput: 671 iput(inode); 672 out_err: 673 return ERR_PTR(err); 674 } 675 676 static int fuse_encode_fh(struct inode *inode, u32 *fh, int *max_len, 677 struct inode *parent) 678 { 679 int len = parent ? 6 : 3; 680 u64 nodeid; 681 u32 generation; 682 683 if (*max_len < len) { 684 *max_len = len; 685 return FILEID_INVALID; 686 } 687 688 nodeid = get_fuse_inode(inode)->nodeid; 689 generation = inode->i_generation; 690 691 fh[0] = (u32)(nodeid >> 32); 692 fh[1] = (u32)(nodeid & 0xffffffff); 693 fh[2] = generation; 694 695 if (parent) { 696 nodeid = get_fuse_inode(parent)->nodeid; 697 generation = parent->i_generation; 698 699 fh[3] = (u32)(nodeid >> 32); 700 fh[4] = (u32)(nodeid & 0xffffffff); 701 fh[5] = generation; 702 } 703 704 *max_len = len; 705 return parent ? 0x82 : 0x81; 706 } 707 708 static struct dentry *fuse_fh_to_dentry(struct super_block *sb, 709 struct fid *fid, int fh_len, int fh_type) 710 { 711 struct fuse_inode_handle handle; 712 713 if ((fh_type != 0x81 && fh_type != 0x82) || fh_len < 3) 714 return NULL; 715 716 handle.nodeid = (u64) fid->raw[0] << 32; 717 handle.nodeid |= (u64) fid->raw[1]; 718 handle.generation = fid->raw[2]; 719 return fuse_get_dentry(sb, &handle); 720 } 721 722 static struct dentry *fuse_fh_to_parent(struct super_block *sb, 723 struct fid *fid, int fh_len, int fh_type) 724 { 725 struct fuse_inode_handle parent; 726 727 if (fh_type != 0x82 || fh_len < 6) 728 return NULL; 729 730 parent.nodeid = (u64) fid->raw[3] << 32; 731 parent.nodeid |= (u64) fid->raw[4]; 732 parent.generation = fid->raw[5]; 733 return fuse_get_dentry(sb, &parent); 734 } 735 736 static struct dentry *fuse_get_parent(struct dentry *child) 737 { 738 struct inode *child_inode = child->d_inode; 739 struct fuse_conn *fc = get_fuse_conn(child_inode); 740 struct inode *inode; 741 struct dentry *parent; 742 struct fuse_entry_out outarg; 743 struct qstr name; 744 int err; 745 746 if (!fc->export_support) 747 return ERR_PTR(-ESTALE); 748 749 name.len = 2; 750 name.name = ".."; 751 err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode), 752 &name, &outarg, &inode); 753 if (err) { 754 if (err == -ENOENT) 755 return ERR_PTR(-ESTALE); 756 return ERR_PTR(err); 757 } 758 759 parent = d_obtain_alias(inode); 760 if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID) 761 fuse_invalidate_entry_cache(parent); 762 763 return parent; 764 } 765 766 static const struct export_operations fuse_export_operations = { 767 .fh_to_dentry = fuse_fh_to_dentry, 768 .fh_to_parent = fuse_fh_to_parent, 769 .encode_fh = fuse_encode_fh, 770 .get_parent = fuse_get_parent, 771 }; 772 773 static const struct super_operations fuse_super_operations = { 774 .alloc_inode = fuse_alloc_inode, 775 .destroy_inode = fuse_destroy_inode, 776 .evict_inode = fuse_evict_inode, 777 .drop_inode = generic_delete_inode, 778 .remount_fs = fuse_remount_fs, 779 .put_super = fuse_put_super, 780 .umount_begin = fuse_umount_begin, 781 .statfs = fuse_statfs, 782 .show_options = fuse_show_options, 783 }; 784 785 static void sanitize_global_limit(unsigned *limit) 786 { 787 if (*limit == 0) 788 *limit = ((num_physpages << PAGE_SHIFT) >> 13) / 789 sizeof(struct fuse_req); 790 791 if (*limit >= 1 << 16) 792 *limit = (1 << 16) - 1; 793 } 794 795 static int set_global_limit(const char *val, struct kernel_param *kp) 796 { 797 int rv; 798 799 rv = param_set_uint(val, kp); 800 if (rv) 801 return rv; 802 803 sanitize_global_limit((unsigned *)kp->arg); 804 805 return 0; 806 } 807 808 static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg) 809 { 810 int cap_sys_admin = capable(CAP_SYS_ADMIN); 811 812 if (arg->minor < 13) 813 return; 814 815 sanitize_global_limit(&max_user_bgreq); 816 sanitize_global_limit(&max_user_congthresh); 817 818 if (arg->max_background) { 819 fc->max_background = arg->max_background; 820 821 if (!cap_sys_admin && fc->max_background > max_user_bgreq) 822 fc->max_background = max_user_bgreq; 823 } 824 if (arg->congestion_threshold) { 825 fc->congestion_threshold = arg->congestion_threshold; 826 827 if (!cap_sys_admin && 828 fc->congestion_threshold > max_user_congthresh) 829 fc->congestion_threshold = max_user_congthresh; 830 } 831 } 832 833 static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req) 834 { 835 struct fuse_init_out *arg = &req->misc.init_out; 836 837 if (req->out.h.error || arg->major != FUSE_KERNEL_VERSION) 838 fc->conn_error = 1; 839 else { 840 unsigned long ra_pages; 841 842 process_init_limits(fc, arg); 843 844 if (arg->minor >= 6) { 845 ra_pages = arg->max_readahead / PAGE_CACHE_SIZE; 846 if (arg->flags & FUSE_ASYNC_READ) 847 fc->async_read = 1; 848 if (!(arg->flags & FUSE_POSIX_LOCKS)) 849 fc->no_lock = 1; 850 if (arg->minor >= 17) { 851 if (!(arg->flags & FUSE_FLOCK_LOCKS)) 852 fc->no_flock = 1; 853 } else { 854 if (!(arg->flags & FUSE_POSIX_LOCKS)) 855 fc->no_flock = 1; 856 } 857 if (arg->flags & FUSE_ATOMIC_O_TRUNC) 858 fc->atomic_o_trunc = 1; 859 if (arg->minor >= 9) { 860 /* LOOKUP has dependency on proto version */ 861 if (arg->flags & FUSE_EXPORT_SUPPORT) 862 fc->export_support = 1; 863 } 864 if (arg->flags & FUSE_BIG_WRITES) 865 fc->big_writes = 1; 866 if (arg->flags & FUSE_DONT_MASK) 867 fc->dont_mask = 1; 868 if (arg->flags & FUSE_AUTO_INVAL_DATA) 869 fc->auto_inval_data = 1; 870 if (arg->flags & FUSE_DO_READDIRPLUS) { 871 fc->do_readdirplus = 1; 872 if (arg->flags & FUSE_READDIRPLUS_AUTO) 873 fc->readdirplus_auto = 1; 874 } 875 if (arg->flags & FUSE_ASYNC_DIO) 876 fc->async_dio = 1; 877 } else { 878 ra_pages = fc->max_read / PAGE_CACHE_SIZE; 879 fc->no_lock = 1; 880 fc->no_flock = 1; 881 } 882 883 fc->bdi.ra_pages = min(fc->bdi.ra_pages, ra_pages); 884 fc->minor = arg->minor; 885 fc->max_write = arg->minor < 5 ? 4096 : arg->max_write; 886 fc->max_write = max_t(unsigned, 4096, fc->max_write); 887 fc->conn_init = 1; 888 } 889 fc->initialized = 1; 890 wake_up_all(&fc->blocked_waitq); 891 } 892 893 static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req) 894 { 895 struct fuse_init_in *arg = &req->misc.init_in; 896 897 arg->major = FUSE_KERNEL_VERSION; 898 arg->minor = FUSE_KERNEL_MINOR_VERSION; 899 arg->max_readahead = fc->bdi.ra_pages * PAGE_CACHE_SIZE; 900 arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC | 901 FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK | 902 FUSE_SPLICE_WRITE | FUSE_SPLICE_MOVE | FUSE_SPLICE_READ | 903 FUSE_FLOCK_LOCKS | FUSE_IOCTL_DIR | FUSE_AUTO_INVAL_DATA | 904 FUSE_DO_READDIRPLUS | FUSE_READDIRPLUS_AUTO | FUSE_ASYNC_DIO; 905 req->in.h.opcode = FUSE_INIT; 906 req->in.numargs = 1; 907 req->in.args[0].size = sizeof(*arg); 908 req->in.args[0].value = arg; 909 req->out.numargs = 1; 910 /* Variable length argument used for backward compatibility 911 with interface version < 7.5. Rest of init_out is zeroed 912 by do_get_request(), so a short reply is not a problem */ 913 req->out.argvar = 1; 914 req->out.args[0].size = sizeof(struct fuse_init_out); 915 req->out.args[0].value = &req->misc.init_out; 916 req->end = process_init_reply; 917 fuse_request_send_background(fc, req); 918 } 919 920 static void fuse_free_conn(struct fuse_conn *fc) 921 { 922 kfree(fc); 923 } 924 925 static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb) 926 { 927 int err; 928 929 fc->bdi.name = "fuse"; 930 fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE; 931 /* fuse does it's own writeback accounting */ 932 fc->bdi.capabilities = BDI_CAP_NO_ACCT_WB; 933 934 err = bdi_init(&fc->bdi); 935 if (err) 936 return err; 937 938 fc->bdi_initialized = 1; 939 940 if (sb->s_bdev) { 941 err = bdi_register(&fc->bdi, NULL, "%u:%u-fuseblk", 942 MAJOR(fc->dev), MINOR(fc->dev)); 943 } else { 944 err = bdi_register_dev(&fc->bdi, fc->dev); 945 } 946 947 if (err) 948 return err; 949 950 /* 951 * For a single fuse filesystem use max 1% of dirty + 952 * writeback threshold. 953 * 954 * This gives about 1M of write buffer for memory maps on a 955 * machine with 1G and 10% dirty_ratio, which should be more 956 * than enough. 957 * 958 * Privileged users can raise it by writing to 959 * 960 * /sys/class/bdi/<bdi>/max_ratio 961 */ 962 bdi_set_max_ratio(&fc->bdi, 1); 963 964 return 0; 965 } 966 967 static int fuse_fill_super(struct super_block *sb, void *data, int silent) 968 { 969 struct fuse_conn *fc; 970 struct inode *root; 971 struct fuse_mount_data d; 972 struct file *file; 973 struct dentry *root_dentry; 974 struct fuse_req *init_req; 975 int err; 976 int is_bdev = sb->s_bdev != NULL; 977 978 err = -EINVAL; 979 if (sb->s_flags & MS_MANDLOCK) 980 goto err; 981 982 sb->s_flags &= ~MS_NOSEC; 983 984 if (!parse_fuse_opt((char *) data, &d, is_bdev)) 985 goto err; 986 987 if (is_bdev) { 988 #ifdef CONFIG_BLOCK 989 err = -EINVAL; 990 if (!sb_set_blocksize(sb, d.blksize)) 991 goto err; 992 #endif 993 } else { 994 sb->s_blocksize = PAGE_CACHE_SIZE; 995 sb->s_blocksize_bits = PAGE_CACHE_SHIFT; 996 } 997 sb->s_magic = FUSE_SUPER_MAGIC; 998 sb->s_op = &fuse_super_operations; 999 sb->s_maxbytes = MAX_LFS_FILESIZE; 1000 sb->s_time_gran = 1; 1001 sb->s_export_op = &fuse_export_operations; 1002 1003 file = fget(d.fd); 1004 err = -EINVAL; 1005 if (!file) 1006 goto err; 1007 1008 if ((file->f_op != &fuse_dev_operations) || 1009 (file->f_cred->user_ns != &init_user_ns)) 1010 goto err_fput; 1011 1012 fc = kmalloc(sizeof(*fc), GFP_KERNEL); 1013 err = -ENOMEM; 1014 if (!fc) 1015 goto err_fput; 1016 1017 fuse_conn_init(fc); 1018 1019 fc->dev = sb->s_dev; 1020 fc->sb = sb; 1021 err = fuse_bdi_init(fc, sb); 1022 if (err) 1023 goto err_put_conn; 1024 1025 sb->s_bdi = &fc->bdi; 1026 1027 /* Handle umasking inside the fuse code */ 1028 if (sb->s_flags & MS_POSIXACL) 1029 fc->dont_mask = 1; 1030 sb->s_flags |= MS_POSIXACL; 1031 1032 fc->release = fuse_free_conn; 1033 fc->flags = d.flags; 1034 fc->user_id = d.user_id; 1035 fc->group_id = d.group_id; 1036 fc->max_read = max_t(unsigned, 4096, d.max_read); 1037 1038 /* Used by get_root_inode() */ 1039 sb->s_fs_info = fc; 1040 1041 err = -ENOMEM; 1042 root = fuse_get_root_inode(sb, d.rootmode); 1043 root_dentry = d_make_root(root); 1044 if (!root_dentry) 1045 goto err_put_conn; 1046 /* only now - we want root dentry with NULL ->d_op */ 1047 sb->s_d_op = &fuse_dentry_operations; 1048 1049 init_req = fuse_request_alloc(0); 1050 if (!init_req) 1051 goto err_put_root; 1052 init_req->background = 1; 1053 1054 if (is_bdev) { 1055 fc->destroy_req = fuse_request_alloc(0); 1056 if (!fc->destroy_req) 1057 goto err_free_init_req; 1058 } 1059 1060 mutex_lock(&fuse_mutex); 1061 err = -EINVAL; 1062 if (file->private_data) 1063 goto err_unlock; 1064 1065 err = fuse_ctl_add_conn(fc); 1066 if (err) 1067 goto err_unlock; 1068 1069 list_add_tail(&fc->entry, &fuse_conn_list); 1070 sb->s_root = root_dentry; 1071 fc->connected = 1; 1072 file->private_data = fuse_conn_get(fc); 1073 mutex_unlock(&fuse_mutex); 1074 /* 1075 * atomic_dec_and_test() in fput() provides the necessary 1076 * memory barrier for file->private_data to be visible on all 1077 * CPUs after this 1078 */ 1079 fput(file); 1080 1081 fuse_send_init(fc, init_req); 1082 1083 return 0; 1084 1085 err_unlock: 1086 mutex_unlock(&fuse_mutex); 1087 err_free_init_req: 1088 fuse_request_free(init_req); 1089 err_put_root: 1090 dput(root_dentry); 1091 err_put_conn: 1092 fuse_bdi_destroy(fc); 1093 fuse_conn_put(fc); 1094 err_fput: 1095 fput(file); 1096 err: 1097 return err; 1098 } 1099 1100 static struct dentry *fuse_mount(struct file_system_type *fs_type, 1101 int flags, const char *dev_name, 1102 void *raw_data) 1103 { 1104 return mount_nodev(fs_type, flags, raw_data, fuse_fill_super); 1105 } 1106 1107 static void fuse_kill_sb_anon(struct super_block *sb) 1108 { 1109 struct fuse_conn *fc = get_fuse_conn_super(sb); 1110 1111 if (fc) { 1112 down_write(&fc->killsb); 1113 fc->sb = NULL; 1114 up_write(&fc->killsb); 1115 } 1116 1117 kill_anon_super(sb); 1118 } 1119 1120 static struct file_system_type fuse_fs_type = { 1121 .owner = THIS_MODULE, 1122 .name = "fuse", 1123 .fs_flags = FS_HAS_SUBTYPE, 1124 .mount = fuse_mount, 1125 .kill_sb = fuse_kill_sb_anon, 1126 }; 1127 MODULE_ALIAS_FS("fuse"); 1128 1129 #ifdef CONFIG_BLOCK 1130 static struct dentry *fuse_mount_blk(struct file_system_type *fs_type, 1131 int flags, const char *dev_name, 1132 void *raw_data) 1133 { 1134 return mount_bdev(fs_type, flags, dev_name, raw_data, fuse_fill_super); 1135 } 1136 1137 static void fuse_kill_sb_blk(struct super_block *sb) 1138 { 1139 struct fuse_conn *fc = get_fuse_conn_super(sb); 1140 1141 if (fc) { 1142 down_write(&fc->killsb); 1143 fc->sb = NULL; 1144 up_write(&fc->killsb); 1145 } 1146 1147 kill_block_super(sb); 1148 } 1149 1150 static struct file_system_type fuseblk_fs_type = { 1151 .owner = THIS_MODULE, 1152 .name = "fuseblk", 1153 .mount = fuse_mount_blk, 1154 .kill_sb = fuse_kill_sb_blk, 1155 .fs_flags = FS_REQUIRES_DEV | FS_HAS_SUBTYPE, 1156 }; 1157 MODULE_ALIAS_FS("fuseblk"); 1158 1159 static inline int register_fuseblk(void) 1160 { 1161 return register_filesystem(&fuseblk_fs_type); 1162 } 1163 1164 static inline void unregister_fuseblk(void) 1165 { 1166 unregister_filesystem(&fuseblk_fs_type); 1167 } 1168 #else 1169 static inline int register_fuseblk(void) 1170 { 1171 return 0; 1172 } 1173 1174 static inline void unregister_fuseblk(void) 1175 { 1176 } 1177 #endif 1178 1179 static void fuse_inode_init_once(void *foo) 1180 { 1181 struct inode *inode = foo; 1182 1183 inode_init_once(inode); 1184 } 1185 1186 static int __init fuse_fs_init(void) 1187 { 1188 int err; 1189 1190 fuse_inode_cachep = kmem_cache_create("fuse_inode", 1191 sizeof(struct fuse_inode), 1192 0, SLAB_HWCACHE_ALIGN, 1193 fuse_inode_init_once); 1194 err = -ENOMEM; 1195 if (!fuse_inode_cachep) 1196 goto out; 1197 1198 err = register_fuseblk(); 1199 if (err) 1200 goto out2; 1201 1202 err = register_filesystem(&fuse_fs_type); 1203 if (err) 1204 goto out3; 1205 1206 return 0; 1207 1208 out3: 1209 unregister_fuseblk(); 1210 out2: 1211 kmem_cache_destroy(fuse_inode_cachep); 1212 out: 1213 return err; 1214 } 1215 1216 static void fuse_fs_cleanup(void) 1217 { 1218 unregister_filesystem(&fuse_fs_type); 1219 unregister_fuseblk(); 1220 1221 /* 1222 * Make sure all delayed rcu free inodes are flushed before we 1223 * destroy cache. 1224 */ 1225 rcu_barrier(); 1226 kmem_cache_destroy(fuse_inode_cachep); 1227 } 1228 1229 static struct kobject *fuse_kobj; 1230 static struct kobject *connections_kobj; 1231 1232 static int fuse_sysfs_init(void) 1233 { 1234 int err; 1235 1236 fuse_kobj = kobject_create_and_add("fuse", fs_kobj); 1237 if (!fuse_kobj) { 1238 err = -ENOMEM; 1239 goto out_err; 1240 } 1241 1242 connections_kobj = kobject_create_and_add("connections", fuse_kobj); 1243 if (!connections_kobj) { 1244 err = -ENOMEM; 1245 goto out_fuse_unregister; 1246 } 1247 1248 return 0; 1249 1250 out_fuse_unregister: 1251 kobject_put(fuse_kobj); 1252 out_err: 1253 return err; 1254 } 1255 1256 static void fuse_sysfs_cleanup(void) 1257 { 1258 kobject_put(connections_kobj); 1259 kobject_put(fuse_kobj); 1260 } 1261 1262 static int __init fuse_init(void) 1263 { 1264 int res; 1265 1266 printk(KERN_INFO "fuse init (API version %i.%i)\n", 1267 FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION); 1268 1269 INIT_LIST_HEAD(&fuse_conn_list); 1270 res = fuse_fs_init(); 1271 if (res) 1272 goto err; 1273 1274 res = fuse_dev_init(); 1275 if (res) 1276 goto err_fs_cleanup; 1277 1278 res = fuse_sysfs_init(); 1279 if (res) 1280 goto err_dev_cleanup; 1281 1282 res = fuse_ctl_init(); 1283 if (res) 1284 goto err_sysfs_cleanup; 1285 1286 sanitize_global_limit(&max_user_bgreq); 1287 sanitize_global_limit(&max_user_congthresh); 1288 1289 return 0; 1290 1291 err_sysfs_cleanup: 1292 fuse_sysfs_cleanup(); 1293 err_dev_cleanup: 1294 fuse_dev_cleanup(); 1295 err_fs_cleanup: 1296 fuse_fs_cleanup(); 1297 err: 1298 return res; 1299 } 1300 1301 static void __exit fuse_exit(void) 1302 { 1303 printk(KERN_DEBUG "fuse exit\n"); 1304 1305 fuse_ctl_cleanup(); 1306 fuse_sysfs_cleanup(); 1307 fuse_fs_cleanup(); 1308 fuse_dev_cleanup(); 1309 } 1310 1311 module_init(fuse_init); 1312 module_exit(fuse_exit); 1313