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 fuse_request_send(fc, req); 350 fuse_put_request(fc, req); 351 } 352 } 353 354 static void fuse_bdi_destroy(struct fuse_conn *fc) 355 { 356 if (fc->bdi_initialized) 357 bdi_destroy(&fc->bdi); 358 } 359 360 void fuse_conn_kill(struct fuse_conn *fc) 361 { 362 spin_lock(&fc->lock); 363 fc->connected = 0; 364 fc->blocked = 0; 365 spin_unlock(&fc->lock); 366 /* Flush all readers on this fs */ 367 kill_fasync(&fc->fasync, SIGIO, POLL_IN); 368 wake_up_all(&fc->waitq); 369 wake_up_all(&fc->blocked_waitq); 370 wake_up_all(&fc->reserved_req_waitq); 371 } 372 EXPORT_SYMBOL_GPL(fuse_conn_kill); 373 374 static void fuse_put_super(struct super_block *sb) 375 { 376 struct fuse_conn *fc = get_fuse_conn_super(sb); 377 378 fuse_send_destroy(fc); 379 380 fuse_conn_kill(fc); 381 mutex_lock(&fuse_mutex); 382 list_del(&fc->entry); 383 fuse_ctl_remove_conn(fc); 384 mutex_unlock(&fuse_mutex); 385 fuse_bdi_destroy(fc); 386 387 fuse_conn_put(fc); 388 } 389 390 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr) 391 { 392 stbuf->f_type = FUSE_SUPER_MAGIC; 393 stbuf->f_bsize = attr->bsize; 394 stbuf->f_frsize = attr->frsize; 395 stbuf->f_blocks = attr->blocks; 396 stbuf->f_bfree = attr->bfree; 397 stbuf->f_bavail = attr->bavail; 398 stbuf->f_files = attr->files; 399 stbuf->f_ffree = attr->ffree; 400 stbuf->f_namelen = attr->namelen; 401 /* fsid is left zero */ 402 } 403 404 static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf) 405 { 406 struct super_block *sb = dentry->d_sb; 407 struct fuse_conn *fc = get_fuse_conn_super(sb); 408 struct fuse_req *req; 409 struct fuse_statfs_out outarg; 410 int err; 411 412 if (!fuse_allow_current_process(fc)) { 413 buf->f_type = FUSE_SUPER_MAGIC; 414 return 0; 415 } 416 417 req = fuse_get_req_nopages(fc); 418 if (IS_ERR(req)) 419 return PTR_ERR(req); 420 421 memset(&outarg, 0, sizeof(outarg)); 422 req->in.numargs = 0; 423 req->in.h.opcode = FUSE_STATFS; 424 req->in.h.nodeid = get_node_id(dentry->d_inode); 425 req->out.numargs = 1; 426 req->out.args[0].size = 427 fc->minor < 4 ? FUSE_COMPAT_STATFS_SIZE : sizeof(outarg); 428 req->out.args[0].value = &outarg; 429 fuse_request_send(fc, req); 430 err = req->out.h.error; 431 if (!err) 432 convert_fuse_statfs(buf, &outarg.st); 433 fuse_put_request(fc, req); 434 return err; 435 } 436 437 enum { 438 OPT_FD, 439 OPT_ROOTMODE, 440 OPT_USER_ID, 441 OPT_GROUP_ID, 442 OPT_DEFAULT_PERMISSIONS, 443 OPT_ALLOW_OTHER, 444 OPT_MAX_READ, 445 OPT_BLKSIZE, 446 OPT_ERR 447 }; 448 449 static const match_table_t tokens = { 450 {OPT_FD, "fd=%u"}, 451 {OPT_ROOTMODE, "rootmode=%o"}, 452 {OPT_USER_ID, "user_id=%u"}, 453 {OPT_GROUP_ID, "group_id=%u"}, 454 {OPT_DEFAULT_PERMISSIONS, "default_permissions"}, 455 {OPT_ALLOW_OTHER, "allow_other"}, 456 {OPT_MAX_READ, "max_read=%u"}, 457 {OPT_BLKSIZE, "blksize=%u"}, 458 {OPT_ERR, NULL} 459 }; 460 461 static int parse_fuse_opt(char *opt, struct fuse_mount_data *d, int is_bdev) 462 { 463 char *p; 464 memset(d, 0, sizeof(struct fuse_mount_data)); 465 d->max_read = ~0; 466 d->blksize = FUSE_DEFAULT_BLKSIZE; 467 468 while ((p = strsep(&opt, ",")) != NULL) { 469 int token; 470 int value; 471 substring_t args[MAX_OPT_ARGS]; 472 if (!*p) 473 continue; 474 475 token = match_token(p, tokens, args); 476 switch (token) { 477 case OPT_FD: 478 if (match_int(&args[0], &value)) 479 return 0; 480 d->fd = value; 481 d->fd_present = 1; 482 break; 483 484 case OPT_ROOTMODE: 485 if (match_octal(&args[0], &value)) 486 return 0; 487 if (!fuse_valid_type(value)) 488 return 0; 489 d->rootmode = value; 490 d->rootmode_present = 1; 491 break; 492 493 case OPT_USER_ID: 494 if (match_int(&args[0], &value)) 495 return 0; 496 d->user_id = make_kuid(current_user_ns(), value); 497 if (!uid_valid(d->user_id)) 498 return 0; 499 d->user_id_present = 1; 500 break; 501 502 case OPT_GROUP_ID: 503 if (match_int(&args[0], &value)) 504 return 0; 505 d->group_id = make_kgid(current_user_ns(), value); 506 if (!gid_valid(d->group_id)) 507 return 0; 508 d->group_id_present = 1; 509 break; 510 511 case OPT_DEFAULT_PERMISSIONS: 512 d->flags |= FUSE_DEFAULT_PERMISSIONS; 513 break; 514 515 case OPT_ALLOW_OTHER: 516 d->flags |= FUSE_ALLOW_OTHER; 517 break; 518 519 case OPT_MAX_READ: 520 if (match_int(&args[0], &value)) 521 return 0; 522 d->max_read = value; 523 break; 524 525 case OPT_BLKSIZE: 526 if (!is_bdev || match_int(&args[0], &value)) 527 return 0; 528 d->blksize = value; 529 break; 530 531 default: 532 return 0; 533 } 534 } 535 536 if (!d->fd_present || !d->rootmode_present || 537 !d->user_id_present || !d->group_id_present) 538 return 0; 539 540 return 1; 541 } 542 543 static int fuse_show_options(struct seq_file *m, struct dentry *root) 544 { 545 struct super_block *sb = root->d_sb; 546 struct fuse_conn *fc = get_fuse_conn_super(sb); 547 548 seq_printf(m, ",user_id=%u", from_kuid_munged(&init_user_ns, fc->user_id)); 549 seq_printf(m, ",group_id=%u", from_kgid_munged(&init_user_ns, fc->group_id)); 550 if (fc->flags & FUSE_DEFAULT_PERMISSIONS) 551 seq_puts(m, ",default_permissions"); 552 if (fc->flags & FUSE_ALLOW_OTHER) 553 seq_puts(m, ",allow_other"); 554 if (fc->max_read != ~0) 555 seq_printf(m, ",max_read=%u", fc->max_read); 556 if (sb->s_bdev && sb->s_blocksize != FUSE_DEFAULT_BLKSIZE) 557 seq_printf(m, ",blksize=%lu", sb->s_blocksize); 558 return 0; 559 } 560 561 void fuse_conn_init(struct fuse_conn *fc) 562 { 563 memset(fc, 0, sizeof(*fc)); 564 spin_lock_init(&fc->lock); 565 mutex_init(&fc->inst_mutex); 566 init_rwsem(&fc->killsb); 567 atomic_set(&fc->count, 1); 568 init_waitqueue_head(&fc->waitq); 569 init_waitqueue_head(&fc->blocked_waitq); 570 init_waitqueue_head(&fc->reserved_req_waitq); 571 INIT_LIST_HEAD(&fc->pending); 572 INIT_LIST_HEAD(&fc->processing); 573 INIT_LIST_HEAD(&fc->io); 574 INIT_LIST_HEAD(&fc->interrupts); 575 INIT_LIST_HEAD(&fc->bg_queue); 576 INIT_LIST_HEAD(&fc->entry); 577 fc->forget_list_tail = &fc->forget_list_head; 578 atomic_set(&fc->num_waiting, 0); 579 fc->max_background = FUSE_DEFAULT_MAX_BACKGROUND; 580 fc->congestion_threshold = FUSE_DEFAULT_CONGESTION_THRESHOLD; 581 fc->khctr = 0; 582 fc->polled_files = RB_ROOT; 583 fc->reqctr = 0; 584 fc->blocked = 1; 585 fc->attr_version = 1; 586 get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key)); 587 } 588 EXPORT_SYMBOL_GPL(fuse_conn_init); 589 590 void fuse_conn_put(struct fuse_conn *fc) 591 { 592 if (atomic_dec_and_test(&fc->count)) { 593 if (fc->destroy_req) 594 fuse_request_free(fc->destroy_req); 595 mutex_destroy(&fc->inst_mutex); 596 fc->release(fc); 597 } 598 } 599 EXPORT_SYMBOL_GPL(fuse_conn_put); 600 601 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc) 602 { 603 atomic_inc(&fc->count); 604 return fc; 605 } 606 EXPORT_SYMBOL_GPL(fuse_conn_get); 607 608 static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned mode) 609 { 610 struct fuse_attr attr; 611 memset(&attr, 0, sizeof(attr)); 612 613 attr.mode = mode; 614 attr.ino = FUSE_ROOT_ID; 615 attr.nlink = 1; 616 return fuse_iget(sb, 1, 0, &attr, 0, 0); 617 } 618 619 struct fuse_inode_handle { 620 u64 nodeid; 621 u32 generation; 622 }; 623 624 static struct dentry *fuse_get_dentry(struct super_block *sb, 625 struct fuse_inode_handle *handle) 626 { 627 struct fuse_conn *fc = get_fuse_conn_super(sb); 628 struct inode *inode; 629 struct dentry *entry; 630 int err = -ESTALE; 631 632 if (handle->nodeid == 0) 633 goto out_err; 634 635 inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid); 636 if (!inode) { 637 struct fuse_entry_out outarg; 638 struct qstr name; 639 640 if (!fc->export_support) 641 goto out_err; 642 643 name.len = 1; 644 name.name = "."; 645 err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg, 646 &inode); 647 if (err && err != -ENOENT) 648 goto out_err; 649 if (err || !inode) { 650 err = -ESTALE; 651 goto out_err; 652 } 653 err = -EIO; 654 if (get_node_id(inode) != handle->nodeid) 655 goto out_iput; 656 } 657 err = -ESTALE; 658 if (inode->i_generation != handle->generation) 659 goto out_iput; 660 661 entry = d_obtain_alias(inode); 662 if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID) 663 fuse_invalidate_entry_cache(entry); 664 665 return entry; 666 667 out_iput: 668 iput(inode); 669 out_err: 670 return ERR_PTR(err); 671 } 672 673 static int fuse_encode_fh(struct inode *inode, u32 *fh, int *max_len, 674 struct inode *parent) 675 { 676 int len = parent ? 6 : 3; 677 u64 nodeid; 678 u32 generation; 679 680 if (*max_len < len) { 681 *max_len = len; 682 return 255; 683 } 684 685 nodeid = get_fuse_inode(inode)->nodeid; 686 generation = inode->i_generation; 687 688 fh[0] = (u32)(nodeid >> 32); 689 fh[1] = (u32)(nodeid & 0xffffffff); 690 fh[2] = generation; 691 692 if (parent) { 693 nodeid = get_fuse_inode(parent)->nodeid; 694 generation = parent->i_generation; 695 696 fh[3] = (u32)(nodeid >> 32); 697 fh[4] = (u32)(nodeid & 0xffffffff); 698 fh[5] = generation; 699 } 700 701 *max_len = len; 702 return parent ? 0x82 : 0x81; 703 } 704 705 static struct dentry *fuse_fh_to_dentry(struct super_block *sb, 706 struct fid *fid, int fh_len, int fh_type) 707 { 708 struct fuse_inode_handle handle; 709 710 if ((fh_type != 0x81 && fh_type != 0x82) || fh_len < 3) 711 return NULL; 712 713 handle.nodeid = (u64) fid->raw[0] << 32; 714 handle.nodeid |= (u64) fid->raw[1]; 715 handle.generation = fid->raw[2]; 716 return fuse_get_dentry(sb, &handle); 717 } 718 719 static struct dentry *fuse_fh_to_parent(struct super_block *sb, 720 struct fid *fid, int fh_len, int fh_type) 721 { 722 struct fuse_inode_handle parent; 723 724 if (fh_type != 0x82 || fh_len < 6) 725 return NULL; 726 727 parent.nodeid = (u64) fid->raw[3] << 32; 728 parent.nodeid |= (u64) fid->raw[4]; 729 parent.generation = fid->raw[5]; 730 return fuse_get_dentry(sb, &parent); 731 } 732 733 static struct dentry *fuse_get_parent(struct dentry *child) 734 { 735 struct inode *child_inode = child->d_inode; 736 struct fuse_conn *fc = get_fuse_conn(child_inode); 737 struct inode *inode; 738 struct dentry *parent; 739 struct fuse_entry_out outarg; 740 struct qstr name; 741 int err; 742 743 if (!fc->export_support) 744 return ERR_PTR(-ESTALE); 745 746 name.len = 2; 747 name.name = ".."; 748 err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode), 749 &name, &outarg, &inode); 750 if (err) { 751 if (err == -ENOENT) 752 return ERR_PTR(-ESTALE); 753 return ERR_PTR(err); 754 } 755 756 parent = d_obtain_alias(inode); 757 if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID) 758 fuse_invalidate_entry_cache(parent); 759 760 return parent; 761 } 762 763 static const struct export_operations fuse_export_operations = { 764 .fh_to_dentry = fuse_fh_to_dentry, 765 .fh_to_parent = fuse_fh_to_parent, 766 .encode_fh = fuse_encode_fh, 767 .get_parent = fuse_get_parent, 768 }; 769 770 static const struct super_operations fuse_super_operations = { 771 .alloc_inode = fuse_alloc_inode, 772 .destroy_inode = fuse_destroy_inode, 773 .evict_inode = fuse_evict_inode, 774 .drop_inode = generic_delete_inode, 775 .remount_fs = fuse_remount_fs, 776 .put_super = fuse_put_super, 777 .umount_begin = fuse_umount_begin, 778 .statfs = fuse_statfs, 779 .show_options = fuse_show_options, 780 }; 781 782 static void sanitize_global_limit(unsigned *limit) 783 { 784 if (*limit == 0) 785 *limit = ((num_physpages << PAGE_SHIFT) >> 13) / 786 sizeof(struct fuse_req); 787 788 if (*limit >= 1 << 16) 789 *limit = (1 << 16) - 1; 790 } 791 792 static int set_global_limit(const char *val, struct kernel_param *kp) 793 { 794 int rv; 795 796 rv = param_set_uint(val, kp); 797 if (rv) 798 return rv; 799 800 sanitize_global_limit((unsigned *)kp->arg); 801 802 return 0; 803 } 804 805 static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg) 806 { 807 int cap_sys_admin = capable(CAP_SYS_ADMIN); 808 809 if (arg->minor < 13) 810 return; 811 812 sanitize_global_limit(&max_user_bgreq); 813 sanitize_global_limit(&max_user_congthresh); 814 815 if (arg->max_background) { 816 fc->max_background = arg->max_background; 817 818 if (!cap_sys_admin && fc->max_background > max_user_bgreq) 819 fc->max_background = max_user_bgreq; 820 } 821 if (arg->congestion_threshold) { 822 fc->congestion_threshold = arg->congestion_threshold; 823 824 if (!cap_sys_admin && 825 fc->congestion_threshold > max_user_congthresh) 826 fc->congestion_threshold = max_user_congthresh; 827 } 828 } 829 830 static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req) 831 { 832 struct fuse_init_out *arg = &req->misc.init_out; 833 834 if (req->out.h.error || arg->major != FUSE_KERNEL_VERSION) 835 fc->conn_error = 1; 836 else { 837 unsigned long ra_pages; 838 839 process_init_limits(fc, arg); 840 841 if (arg->minor >= 6) { 842 ra_pages = arg->max_readahead / PAGE_CACHE_SIZE; 843 if (arg->flags & FUSE_ASYNC_READ) 844 fc->async_read = 1; 845 if (!(arg->flags & FUSE_POSIX_LOCKS)) 846 fc->no_lock = 1; 847 if (arg->minor >= 17) { 848 if (!(arg->flags & FUSE_FLOCK_LOCKS)) 849 fc->no_flock = 1; 850 } else { 851 if (!(arg->flags & FUSE_POSIX_LOCKS)) 852 fc->no_flock = 1; 853 } 854 if (arg->flags & FUSE_ATOMIC_O_TRUNC) 855 fc->atomic_o_trunc = 1; 856 if (arg->minor >= 9) { 857 /* LOOKUP has dependency on proto version */ 858 if (arg->flags & FUSE_EXPORT_SUPPORT) 859 fc->export_support = 1; 860 } 861 if (arg->flags & FUSE_BIG_WRITES) 862 fc->big_writes = 1; 863 if (arg->flags & FUSE_DONT_MASK) 864 fc->dont_mask = 1; 865 if (arg->flags & FUSE_AUTO_INVAL_DATA) 866 fc->auto_inval_data = 1; 867 if (arg->flags & FUSE_DO_READDIRPLUS) 868 fc->do_readdirplus = 1; 869 } else { 870 ra_pages = fc->max_read / PAGE_CACHE_SIZE; 871 fc->no_lock = 1; 872 fc->no_flock = 1; 873 } 874 875 fc->bdi.ra_pages = min(fc->bdi.ra_pages, ra_pages); 876 fc->minor = arg->minor; 877 fc->max_write = arg->minor < 5 ? 4096 : arg->max_write; 878 fc->max_write = max_t(unsigned, 4096, fc->max_write); 879 fc->conn_init = 1; 880 } 881 fc->blocked = 0; 882 wake_up_all(&fc->blocked_waitq); 883 } 884 885 static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req) 886 { 887 struct fuse_init_in *arg = &req->misc.init_in; 888 889 arg->major = FUSE_KERNEL_VERSION; 890 arg->minor = FUSE_KERNEL_MINOR_VERSION; 891 arg->max_readahead = fc->bdi.ra_pages * PAGE_CACHE_SIZE; 892 arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC | 893 FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK | 894 FUSE_SPLICE_WRITE | FUSE_SPLICE_MOVE | FUSE_SPLICE_READ | 895 FUSE_FLOCK_LOCKS | FUSE_IOCTL_DIR | FUSE_AUTO_INVAL_DATA | 896 FUSE_DO_READDIRPLUS; 897 req->in.h.opcode = FUSE_INIT; 898 req->in.numargs = 1; 899 req->in.args[0].size = sizeof(*arg); 900 req->in.args[0].value = arg; 901 req->out.numargs = 1; 902 /* Variable length argument used for backward compatibility 903 with interface version < 7.5. Rest of init_out is zeroed 904 by do_get_request(), so a short reply is not a problem */ 905 req->out.argvar = 1; 906 req->out.args[0].size = sizeof(struct fuse_init_out); 907 req->out.args[0].value = &req->misc.init_out; 908 req->end = process_init_reply; 909 fuse_request_send_background(fc, req); 910 } 911 912 static void fuse_free_conn(struct fuse_conn *fc) 913 { 914 kfree(fc); 915 } 916 917 static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb) 918 { 919 int err; 920 921 fc->bdi.name = "fuse"; 922 fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE; 923 /* fuse does it's own writeback accounting */ 924 fc->bdi.capabilities = BDI_CAP_NO_ACCT_WB; 925 926 err = bdi_init(&fc->bdi); 927 if (err) 928 return err; 929 930 fc->bdi_initialized = 1; 931 932 if (sb->s_bdev) { 933 err = bdi_register(&fc->bdi, NULL, "%u:%u-fuseblk", 934 MAJOR(fc->dev), MINOR(fc->dev)); 935 } else { 936 err = bdi_register_dev(&fc->bdi, fc->dev); 937 } 938 939 if (err) 940 return err; 941 942 /* 943 * For a single fuse filesystem use max 1% of dirty + 944 * writeback threshold. 945 * 946 * This gives about 1M of write buffer for memory maps on a 947 * machine with 1G and 10% dirty_ratio, which should be more 948 * than enough. 949 * 950 * Privileged users can raise it by writing to 951 * 952 * /sys/class/bdi/<bdi>/max_ratio 953 */ 954 bdi_set_max_ratio(&fc->bdi, 1); 955 956 return 0; 957 } 958 959 static int fuse_fill_super(struct super_block *sb, void *data, int silent) 960 { 961 struct fuse_conn *fc; 962 struct inode *root; 963 struct fuse_mount_data d; 964 struct file *file; 965 struct dentry *root_dentry; 966 struct fuse_req *init_req; 967 int err; 968 int is_bdev = sb->s_bdev != NULL; 969 970 err = -EINVAL; 971 if (sb->s_flags & MS_MANDLOCK) 972 goto err; 973 974 sb->s_flags &= ~MS_NOSEC; 975 976 if (!parse_fuse_opt((char *) data, &d, is_bdev)) 977 goto err; 978 979 if (is_bdev) { 980 #ifdef CONFIG_BLOCK 981 err = -EINVAL; 982 if (!sb_set_blocksize(sb, d.blksize)) 983 goto err; 984 #endif 985 } else { 986 sb->s_blocksize = PAGE_CACHE_SIZE; 987 sb->s_blocksize_bits = PAGE_CACHE_SHIFT; 988 } 989 sb->s_magic = FUSE_SUPER_MAGIC; 990 sb->s_op = &fuse_super_operations; 991 sb->s_maxbytes = MAX_LFS_FILESIZE; 992 sb->s_time_gran = 1; 993 sb->s_export_op = &fuse_export_operations; 994 995 file = fget(d.fd); 996 err = -EINVAL; 997 if (!file) 998 goto err; 999 1000 if ((file->f_op != &fuse_dev_operations) || 1001 (file->f_cred->user_ns != &init_user_ns)) 1002 goto err_fput; 1003 1004 fc = kmalloc(sizeof(*fc), GFP_KERNEL); 1005 err = -ENOMEM; 1006 if (!fc) 1007 goto err_fput; 1008 1009 fuse_conn_init(fc); 1010 1011 fc->dev = sb->s_dev; 1012 fc->sb = sb; 1013 err = fuse_bdi_init(fc, sb); 1014 if (err) 1015 goto err_put_conn; 1016 1017 sb->s_bdi = &fc->bdi; 1018 1019 /* Handle umasking inside the fuse code */ 1020 if (sb->s_flags & MS_POSIXACL) 1021 fc->dont_mask = 1; 1022 sb->s_flags |= MS_POSIXACL; 1023 1024 fc->release = fuse_free_conn; 1025 fc->flags = d.flags; 1026 fc->user_id = d.user_id; 1027 fc->group_id = d.group_id; 1028 fc->max_read = max_t(unsigned, 4096, d.max_read); 1029 1030 /* Used by get_root_inode() */ 1031 sb->s_fs_info = fc; 1032 1033 err = -ENOMEM; 1034 root = fuse_get_root_inode(sb, d.rootmode); 1035 root_dentry = d_make_root(root); 1036 if (!root_dentry) 1037 goto err_put_conn; 1038 /* only now - we want root dentry with NULL ->d_op */ 1039 sb->s_d_op = &fuse_dentry_operations; 1040 1041 init_req = fuse_request_alloc(0); 1042 if (!init_req) 1043 goto err_put_root; 1044 1045 if (is_bdev) { 1046 fc->destroy_req = fuse_request_alloc(0); 1047 if (!fc->destroy_req) 1048 goto err_free_init_req; 1049 } 1050 1051 mutex_lock(&fuse_mutex); 1052 err = -EINVAL; 1053 if (file->private_data) 1054 goto err_unlock; 1055 1056 err = fuse_ctl_add_conn(fc); 1057 if (err) 1058 goto err_unlock; 1059 1060 list_add_tail(&fc->entry, &fuse_conn_list); 1061 sb->s_root = root_dentry; 1062 fc->connected = 1; 1063 file->private_data = fuse_conn_get(fc); 1064 mutex_unlock(&fuse_mutex); 1065 /* 1066 * atomic_dec_and_test() in fput() provides the necessary 1067 * memory barrier for file->private_data to be visible on all 1068 * CPUs after this 1069 */ 1070 fput(file); 1071 1072 fuse_send_init(fc, init_req); 1073 1074 return 0; 1075 1076 err_unlock: 1077 mutex_unlock(&fuse_mutex); 1078 err_free_init_req: 1079 fuse_request_free(init_req); 1080 err_put_root: 1081 dput(root_dentry); 1082 err_put_conn: 1083 fuse_bdi_destroy(fc); 1084 fuse_conn_put(fc); 1085 err_fput: 1086 fput(file); 1087 err: 1088 return err; 1089 } 1090 1091 static struct dentry *fuse_mount(struct file_system_type *fs_type, 1092 int flags, const char *dev_name, 1093 void *raw_data) 1094 { 1095 return mount_nodev(fs_type, flags, raw_data, fuse_fill_super); 1096 } 1097 1098 static void fuse_kill_sb_anon(struct super_block *sb) 1099 { 1100 struct fuse_conn *fc = get_fuse_conn_super(sb); 1101 1102 if (fc) { 1103 down_write(&fc->killsb); 1104 fc->sb = NULL; 1105 up_write(&fc->killsb); 1106 } 1107 1108 kill_anon_super(sb); 1109 } 1110 1111 static struct file_system_type fuse_fs_type = { 1112 .owner = THIS_MODULE, 1113 .name = "fuse", 1114 .fs_flags = FS_HAS_SUBTYPE, 1115 .mount = fuse_mount, 1116 .kill_sb = fuse_kill_sb_anon, 1117 }; 1118 1119 #ifdef CONFIG_BLOCK 1120 static struct dentry *fuse_mount_blk(struct file_system_type *fs_type, 1121 int flags, const char *dev_name, 1122 void *raw_data) 1123 { 1124 return mount_bdev(fs_type, flags, dev_name, raw_data, fuse_fill_super); 1125 } 1126 1127 static void fuse_kill_sb_blk(struct super_block *sb) 1128 { 1129 struct fuse_conn *fc = get_fuse_conn_super(sb); 1130 1131 if (fc) { 1132 down_write(&fc->killsb); 1133 fc->sb = NULL; 1134 up_write(&fc->killsb); 1135 } 1136 1137 kill_block_super(sb); 1138 } 1139 1140 static struct file_system_type fuseblk_fs_type = { 1141 .owner = THIS_MODULE, 1142 .name = "fuseblk", 1143 .mount = fuse_mount_blk, 1144 .kill_sb = fuse_kill_sb_blk, 1145 .fs_flags = FS_REQUIRES_DEV | FS_HAS_SUBTYPE, 1146 }; 1147 1148 static inline int register_fuseblk(void) 1149 { 1150 return register_filesystem(&fuseblk_fs_type); 1151 } 1152 1153 static inline void unregister_fuseblk(void) 1154 { 1155 unregister_filesystem(&fuseblk_fs_type); 1156 } 1157 #else 1158 static inline int register_fuseblk(void) 1159 { 1160 return 0; 1161 } 1162 1163 static inline void unregister_fuseblk(void) 1164 { 1165 } 1166 #endif 1167 1168 static void fuse_inode_init_once(void *foo) 1169 { 1170 struct inode *inode = foo; 1171 1172 inode_init_once(inode); 1173 } 1174 1175 static int __init fuse_fs_init(void) 1176 { 1177 int err; 1178 1179 fuse_inode_cachep = kmem_cache_create("fuse_inode", 1180 sizeof(struct fuse_inode), 1181 0, SLAB_HWCACHE_ALIGN, 1182 fuse_inode_init_once); 1183 err = -ENOMEM; 1184 if (!fuse_inode_cachep) 1185 goto out; 1186 1187 err = register_fuseblk(); 1188 if (err) 1189 goto out2; 1190 1191 err = register_filesystem(&fuse_fs_type); 1192 if (err) 1193 goto out3; 1194 1195 return 0; 1196 1197 out3: 1198 unregister_fuseblk(); 1199 out2: 1200 kmem_cache_destroy(fuse_inode_cachep); 1201 out: 1202 return err; 1203 } 1204 1205 static void fuse_fs_cleanup(void) 1206 { 1207 unregister_filesystem(&fuse_fs_type); 1208 unregister_fuseblk(); 1209 1210 /* 1211 * Make sure all delayed rcu free inodes are flushed before we 1212 * destroy cache. 1213 */ 1214 rcu_barrier(); 1215 kmem_cache_destroy(fuse_inode_cachep); 1216 } 1217 1218 static struct kobject *fuse_kobj; 1219 static struct kobject *connections_kobj; 1220 1221 static int fuse_sysfs_init(void) 1222 { 1223 int err; 1224 1225 fuse_kobj = kobject_create_and_add("fuse", fs_kobj); 1226 if (!fuse_kobj) { 1227 err = -ENOMEM; 1228 goto out_err; 1229 } 1230 1231 connections_kobj = kobject_create_and_add("connections", fuse_kobj); 1232 if (!connections_kobj) { 1233 err = -ENOMEM; 1234 goto out_fuse_unregister; 1235 } 1236 1237 return 0; 1238 1239 out_fuse_unregister: 1240 kobject_put(fuse_kobj); 1241 out_err: 1242 return err; 1243 } 1244 1245 static void fuse_sysfs_cleanup(void) 1246 { 1247 kobject_put(connections_kobj); 1248 kobject_put(fuse_kobj); 1249 } 1250 1251 static int __init fuse_init(void) 1252 { 1253 int res; 1254 1255 printk(KERN_INFO "fuse init (API version %i.%i)\n", 1256 FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION); 1257 1258 INIT_LIST_HEAD(&fuse_conn_list); 1259 res = fuse_fs_init(); 1260 if (res) 1261 goto err; 1262 1263 res = fuse_dev_init(); 1264 if (res) 1265 goto err_fs_cleanup; 1266 1267 res = fuse_sysfs_init(); 1268 if (res) 1269 goto err_dev_cleanup; 1270 1271 res = fuse_ctl_init(); 1272 if (res) 1273 goto err_sysfs_cleanup; 1274 1275 sanitize_global_limit(&max_user_bgreq); 1276 sanitize_global_limit(&max_user_congthresh); 1277 1278 return 0; 1279 1280 err_sysfs_cleanup: 1281 fuse_sysfs_cleanup(); 1282 err_dev_cleanup: 1283 fuse_dev_cleanup(); 1284 err_fs_cleanup: 1285 fuse_fs_cleanup(); 1286 err: 1287 return res; 1288 } 1289 1290 static void __exit fuse_exit(void) 1291 { 1292 printk(KERN_DEBUG "fuse exit\n"); 1293 1294 fuse_ctl_cleanup(); 1295 fuse_sysfs_cleanup(); 1296 fuse_fs_cleanup(); 1297 fuse_dev_cleanup(); 1298 } 1299 1300 module_init(fuse_init); 1301 module_exit(fuse_exit); 1302