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