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 unsigned user_id; 64 unsigned 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 = attr->uid; 168 inode->i_gid = 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_task(fc, current)) { 412 buf->f_type = FUSE_SUPER_MAGIC; 413 return 0; 414 } 415 416 req = fuse_get_req(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 = value; 496 d->user_id_present = 1; 497 break; 498 499 case OPT_GROUP_ID: 500 if (match_int(&args[0], &value)) 501 return 0; 502 d->group_id = value; 503 d->group_id_present = 1; 504 break; 505 506 case OPT_DEFAULT_PERMISSIONS: 507 d->flags |= FUSE_DEFAULT_PERMISSIONS; 508 break; 509 510 case OPT_ALLOW_OTHER: 511 d->flags |= FUSE_ALLOW_OTHER; 512 break; 513 514 case OPT_MAX_READ: 515 if (match_int(&args[0], &value)) 516 return 0; 517 d->max_read = value; 518 break; 519 520 case OPT_BLKSIZE: 521 if (!is_bdev || match_int(&args[0], &value)) 522 return 0; 523 d->blksize = value; 524 break; 525 526 default: 527 return 0; 528 } 529 } 530 531 if (!d->fd_present || !d->rootmode_present || 532 !d->user_id_present || !d->group_id_present) 533 return 0; 534 535 return 1; 536 } 537 538 static int fuse_show_options(struct seq_file *m, struct dentry *root) 539 { 540 struct super_block *sb = root->d_sb; 541 struct fuse_conn *fc = get_fuse_conn_super(sb); 542 543 seq_printf(m, ",user_id=%u", fc->user_id); 544 seq_printf(m, ",group_id=%u", fc->group_id); 545 if (fc->flags & FUSE_DEFAULT_PERMISSIONS) 546 seq_puts(m, ",default_permissions"); 547 if (fc->flags & FUSE_ALLOW_OTHER) 548 seq_puts(m, ",allow_other"); 549 if (fc->max_read != ~0) 550 seq_printf(m, ",max_read=%u", fc->max_read); 551 if (sb->s_bdev && sb->s_blocksize != FUSE_DEFAULT_BLKSIZE) 552 seq_printf(m, ",blksize=%lu", sb->s_blocksize); 553 return 0; 554 } 555 556 void fuse_conn_init(struct fuse_conn *fc) 557 { 558 memset(fc, 0, sizeof(*fc)); 559 spin_lock_init(&fc->lock); 560 mutex_init(&fc->inst_mutex); 561 init_rwsem(&fc->killsb); 562 atomic_set(&fc->count, 1); 563 init_waitqueue_head(&fc->waitq); 564 init_waitqueue_head(&fc->blocked_waitq); 565 init_waitqueue_head(&fc->reserved_req_waitq); 566 INIT_LIST_HEAD(&fc->pending); 567 INIT_LIST_HEAD(&fc->processing); 568 INIT_LIST_HEAD(&fc->io); 569 INIT_LIST_HEAD(&fc->interrupts); 570 INIT_LIST_HEAD(&fc->bg_queue); 571 INIT_LIST_HEAD(&fc->entry); 572 fc->forget_list_tail = &fc->forget_list_head; 573 atomic_set(&fc->num_waiting, 0); 574 fc->max_background = FUSE_DEFAULT_MAX_BACKGROUND; 575 fc->congestion_threshold = FUSE_DEFAULT_CONGESTION_THRESHOLD; 576 fc->khctr = 0; 577 fc->polled_files = RB_ROOT; 578 fc->reqctr = 0; 579 fc->blocked = 1; 580 fc->attr_version = 1; 581 get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key)); 582 } 583 EXPORT_SYMBOL_GPL(fuse_conn_init); 584 585 void fuse_conn_put(struct fuse_conn *fc) 586 { 587 if (atomic_dec_and_test(&fc->count)) { 588 if (fc->destroy_req) 589 fuse_request_free(fc->destroy_req); 590 mutex_destroy(&fc->inst_mutex); 591 fc->release(fc); 592 } 593 } 594 EXPORT_SYMBOL_GPL(fuse_conn_put); 595 596 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc) 597 { 598 atomic_inc(&fc->count); 599 return fc; 600 } 601 EXPORT_SYMBOL_GPL(fuse_conn_get); 602 603 static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned mode) 604 { 605 struct fuse_attr attr; 606 memset(&attr, 0, sizeof(attr)); 607 608 attr.mode = mode; 609 attr.ino = FUSE_ROOT_ID; 610 attr.nlink = 1; 611 return fuse_iget(sb, 1, 0, &attr, 0, 0); 612 } 613 614 struct fuse_inode_handle { 615 u64 nodeid; 616 u32 generation; 617 }; 618 619 static struct dentry *fuse_get_dentry(struct super_block *sb, 620 struct fuse_inode_handle *handle) 621 { 622 struct fuse_conn *fc = get_fuse_conn_super(sb); 623 struct inode *inode; 624 struct dentry *entry; 625 int err = -ESTALE; 626 627 if (handle->nodeid == 0) 628 goto out_err; 629 630 inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid); 631 if (!inode) { 632 struct fuse_entry_out outarg; 633 struct qstr name; 634 635 if (!fc->export_support) 636 goto out_err; 637 638 name.len = 1; 639 name.name = "."; 640 err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg, 641 &inode); 642 if (err && err != -ENOENT) 643 goto out_err; 644 if (err || !inode) { 645 err = -ESTALE; 646 goto out_err; 647 } 648 err = -EIO; 649 if (get_node_id(inode) != handle->nodeid) 650 goto out_iput; 651 } 652 err = -ESTALE; 653 if (inode->i_generation != handle->generation) 654 goto out_iput; 655 656 entry = d_obtain_alias(inode); 657 if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID) 658 fuse_invalidate_entry_cache(entry); 659 660 return entry; 661 662 out_iput: 663 iput(inode); 664 out_err: 665 return ERR_PTR(err); 666 } 667 668 static int fuse_encode_fh(struct inode *inode, u32 *fh, int *max_len, 669 struct inode *parent) 670 { 671 int len = parent ? 6 : 3; 672 u64 nodeid; 673 u32 generation; 674 675 if (*max_len < len) { 676 *max_len = len; 677 return 255; 678 } 679 680 nodeid = get_fuse_inode(inode)->nodeid; 681 generation = inode->i_generation; 682 683 fh[0] = (u32)(nodeid >> 32); 684 fh[1] = (u32)(nodeid & 0xffffffff); 685 fh[2] = generation; 686 687 if (parent) { 688 nodeid = get_fuse_inode(parent)->nodeid; 689 generation = parent->i_generation; 690 691 fh[3] = (u32)(nodeid >> 32); 692 fh[4] = (u32)(nodeid & 0xffffffff); 693 fh[5] = generation; 694 } 695 696 *max_len = len; 697 return parent ? 0x82 : 0x81; 698 } 699 700 static struct dentry *fuse_fh_to_dentry(struct super_block *sb, 701 struct fid *fid, int fh_len, int fh_type) 702 { 703 struct fuse_inode_handle handle; 704 705 if ((fh_type != 0x81 && fh_type != 0x82) || fh_len < 3) 706 return NULL; 707 708 handle.nodeid = (u64) fid->raw[0] << 32; 709 handle.nodeid |= (u64) fid->raw[1]; 710 handle.generation = fid->raw[2]; 711 return fuse_get_dentry(sb, &handle); 712 } 713 714 static struct dentry *fuse_fh_to_parent(struct super_block *sb, 715 struct fid *fid, int fh_len, int fh_type) 716 { 717 struct fuse_inode_handle parent; 718 719 if (fh_type != 0x82 || fh_len < 6) 720 return NULL; 721 722 parent.nodeid = (u64) fid->raw[3] << 32; 723 parent.nodeid |= (u64) fid->raw[4]; 724 parent.generation = fid->raw[5]; 725 return fuse_get_dentry(sb, &parent); 726 } 727 728 static struct dentry *fuse_get_parent(struct dentry *child) 729 { 730 struct inode *child_inode = child->d_inode; 731 struct fuse_conn *fc = get_fuse_conn(child_inode); 732 struct inode *inode; 733 struct dentry *parent; 734 struct fuse_entry_out outarg; 735 struct qstr name; 736 int err; 737 738 if (!fc->export_support) 739 return ERR_PTR(-ESTALE); 740 741 name.len = 2; 742 name.name = ".."; 743 err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode), 744 &name, &outarg, &inode); 745 if (err) { 746 if (err == -ENOENT) 747 return ERR_PTR(-ESTALE); 748 return ERR_PTR(err); 749 } 750 751 parent = d_obtain_alias(inode); 752 if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID) 753 fuse_invalidate_entry_cache(parent); 754 755 return parent; 756 } 757 758 static const struct export_operations fuse_export_operations = { 759 .fh_to_dentry = fuse_fh_to_dentry, 760 .fh_to_parent = fuse_fh_to_parent, 761 .encode_fh = fuse_encode_fh, 762 .get_parent = fuse_get_parent, 763 }; 764 765 static const struct super_operations fuse_super_operations = { 766 .alloc_inode = fuse_alloc_inode, 767 .destroy_inode = fuse_destroy_inode, 768 .evict_inode = fuse_evict_inode, 769 .drop_inode = generic_delete_inode, 770 .remount_fs = fuse_remount_fs, 771 .put_super = fuse_put_super, 772 .umount_begin = fuse_umount_begin, 773 .statfs = fuse_statfs, 774 .show_options = fuse_show_options, 775 }; 776 777 static void sanitize_global_limit(unsigned *limit) 778 { 779 if (*limit == 0) 780 *limit = ((num_physpages << PAGE_SHIFT) >> 13) / 781 sizeof(struct fuse_req); 782 783 if (*limit >= 1 << 16) 784 *limit = (1 << 16) - 1; 785 } 786 787 static int set_global_limit(const char *val, struct kernel_param *kp) 788 { 789 int rv; 790 791 rv = param_set_uint(val, kp); 792 if (rv) 793 return rv; 794 795 sanitize_global_limit((unsigned *)kp->arg); 796 797 return 0; 798 } 799 800 static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg) 801 { 802 int cap_sys_admin = capable(CAP_SYS_ADMIN); 803 804 if (arg->minor < 13) 805 return; 806 807 sanitize_global_limit(&max_user_bgreq); 808 sanitize_global_limit(&max_user_congthresh); 809 810 if (arg->max_background) { 811 fc->max_background = arg->max_background; 812 813 if (!cap_sys_admin && fc->max_background > max_user_bgreq) 814 fc->max_background = max_user_bgreq; 815 } 816 if (arg->congestion_threshold) { 817 fc->congestion_threshold = arg->congestion_threshold; 818 819 if (!cap_sys_admin && 820 fc->congestion_threshold > max_user_congthresh) 821 fc->congestion_threshold = max_user_congthresh; 822 } 823 } 824 825 static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req) 826 { 827 struct fuse_init_out *arg = &req->misc.init_out; 828 829 if (req->out.h.error || arg->major != FUSE_KERNEL_VERSION) 830 fc->conn_error = 1; 831 else { 832 unsigned long ra_pages; 833 834 process_init_limits(fc, arg); 835 836 if (arg->minor >= 6) { 837 ra_pages = arg->max_readahead / PAGE_CACHE_SIZE; 838 if (arg->flags & FUSE_ASYNC_READ) 839 fc->async_read = 1; 840 if (!(arg->flags & FUSE_POSIX_LOCKS)) 841 fc->no_lock = 1; 842 if (arg->minor >= 17) { 843 if (!(arg->flags & FUSE_FLOCK_LOCKS)) 844 fc->no_flock = 1; 845 } else { 846 if (!(arg->flags & FUSE_POSIX_LOCKS)) 847 fc->no_flock = 1; 848 } 849 if (arg->flags & FUSE_ATOMIC_O_TRUNC) 850 fc->atomic_o_trunc = 1; 851 if (arg->minor >= 9) { 852 /* LOOKUP has dependency on proto version */ 853 if (arg->flags & FUSE_EXPORT_SUPPORT) 854 fc->export_support = 1; 855 } 856 if (arg->flags & FUSE_BIG_WRITES) 857 fc->big_writes = 1; 858 if (arg->flags & FUSE_DONT_MASK) 859 fc->dont_mask = 1; 860 if (arg->flags & FUSE_AUTO_INVAL_DATA) 861 fc->auto_inval_data = 1; 862 } else { 863 ra_pages = fc->max_read / PAGE_CACHE_SIZE; 864 fc->no_lock = 1; 865 fc->no_flock = 1; 866 } 867 868 fc->bdi.ra_pages = min(fc->bdi.ra_pages, ra_pages); 869 fc->minor = arg->minor; 870 fc->max_write = arg->minor < 5 ? 4096 : arg->max_write; 871 fc->max_write = max_t(unsigned, 4096, fc->max_write); 872 fc->conn_init = 1; 873 } 874 fc->blocked = 0; 875 wake_up_all(&fc->blocked_waitq); 876 } 877 878 static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req) 879 { 880 struct fuse_init_in *arg = &req->misc.init_in; 881 882 arg->major = FUSE_KERNEL_VERSION; 883 arg->minor = FUSE_KERNEL_MINOR_VERSION; 884 arg->max_readahead = fc->bdi.ra_pages * PAGE_CACHE_SIZE; 885 arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC | 886 FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK | 887 FUSE_SPLICE_WRITE | FUSE_SPLICE_MOVE | FUSE_SPLICE_READ | 888 FUSE_FLOCK_LOCKS | FUSE_IOCTL_DIR | FUSE_AUTO_INVAL_DATA; 889 req->in.h.opcode = FUSE_INIT; 890 req->in.numargs = 1; 891 req->in.args[0].size = sizeof(*arg); 892 req->in.args[0].value = arg; 893 req->out.numargs = 1; 894 /* Variable length argument used for backward compatibility 895 with interface version < 7.5. Rest of init_out is zeroed 896 by do_get_request(), so a short reply is not a problem */ 897 req->out.argvar = 1; 898 req->out.args[0].size = sizeof(struct fuse_init_out); 899 req->out.args[0].value = &req->misc.init_out; 900 req->end = process_init_reply; 901 fuse_request_send_background(fc, req); 902 } 903 904 static void fuse_free_conn(struct fuse_conn *fc) 905 { 906 kfree(fc); 907 } 908 909 static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb) 910 { 911 int err; 912 913 fc->bdi.name = "fuse"; 914 fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE; 915 /* fuse does it's own writeback accounting */ 916 fc->bdi.capabilities = BDI_CAP_NO_ACCT_WB; 917 918 err = bdi_init(&fc->bdi); 919 if (err) 920 return err; 921 922 fc->bdi_initialized = 1; 923 924 if (sb->s_bdev) { 925 err = bdi_register(&fc->bdi, NULL, "%u:%u-fuseblk", 926 MAJOR(fc->dev), MINOR(fc->dev)); 927 } else { 928 err = bdi_register_dev(&fc->bdi, fc->dev); 929 } 930 931 if (err) 932 return err; 933 934 /* 935 * For a single fuse filesystem use max 1% of dirty + 936 * writeback threshold. 937 * 938 * This gives about 1M of write buffer for memory maps on a 939 * machine with 1G and 10% dirty_ratio, which should be more 940 * than enough. 941 * 942 * Privileged users can raise it by writing to 943 * 944 * /sys/class/bdi/<bdi>/max_ratio 945 */ 946 bdi_set_max_ratio(&fc->bdi, 1); 947 948 return 0; 949 } 950 951 static int fuse_fill_super(struct super_block *sb, void *data, int silent) 952 { 953 struct fuse_conn *fc; 954 struct inode *root; 955 struct fuse_mount_data d; 956 struct file *file; 957 struct dentry *root_dentry; 958 struct fuse_req *init_req; 959 int err; 960 int is_bdev = sb->s_bdev != NULL; 961 962 err = -EINVAL; 963 if (sb->s_flags & MS_MANDLOCK) 964 goto err; 965 966 sb->s_flags &= ~MS_NOSEC; 967 968 if (!parse_fuse_opt((char *) data, &d, is_bdev)) 969 goto err; 970 971 if (is_bdev) { 972 #ifdef CONFIG_BLOCK 973 err = -EINVAL; 974 if (!sb_set_blocksize(sb, d.blksize)) 975 goto err; 976 #endif 977 } else { 978 sb->s_blocksize = PAGE_CACHE_SIZE; 979 sb->s_blocksize_bits = PAGE_CACHE_SHIFT; 980 } 981 sb->s_magic = FUSE_SUPER_MAGIC; 982 sb->s_op = &fuse_super_operations; 983 sb->s_maxbytes = MAX_LFS_FILESIZE; 984 sb->s_time_gran = 1; 985 sb->s_export_op = &fuse_export_operations; 986 987 file = fget(d.fd); 988 err = -EINVAL; 989 if (!file) 990 goto err; 991 992 if (file->f_op != &fuse_dev_operations) 993 goto err_fput; 994 995 fc = kmalloc(sizeof(*fc), GFP_KERNEL); 996 err = -ENOMEM; 997 if (!fc) 998 goto err_fput; 999 1000 fuse_conn_init(fc); 1001 1002 fc->dev = sb->s_dev; 1003 fc->sb = sb; 1004 err = fuse_bdi_init(fc, sb); 1005 if (err) 1006 goto err_put_conn; 1007 1008 sb->s_bdi = &fc->bdi; 1009 1010 /* Handle umasking inside the fuse code */ 1011 if (sb->s_flags & MS_POSIXACL) 1012 fc->dont_mask = 1; 1013 sb->s_flags |= MS_POSIXACL; 1014 1015 fc->release = fuse_free_conn; 1016 fc->flags = d.flags; 1017 fc->user_id = d.user_id; 1018 fc->group_id = d.group_id; 1019 fc->max_read = max_t(unsigned, 4096, d.max_read); 1020 1021 /* Used by get_root_inode() */ 1022 sb->s_fs_info = fc; 1023 1024 err = -ENOMEM; 1025 root = fuse_get_root_inode(sb, d.rootmode); 1026 root_dentry = d_make_root(root); 1027 if (!root_dentry) 1028 goto err_put_conn; 1029 /* only now - we want root dentry with NULL ->d_op */ 1030 sb->s_d_op = &fuse_dentry_operations; 1031 1032 init_req = fuse_request_alloc(); 1033 if (!init_req) 1034 goto err_put_root; 1035 1036 if (is_bdev) { 1037 fc->destroy_req = fuse_request_alloc(); 1038 if (!fc->destroy_req) 1039 goto err_free_init_req; 1040 } 1041 1042 mutex_lock(&fuse_mutex); 1043 err = -EINVAL; 1044 if (file->private_data) 1045 goto err_unlock; 1046 1047 err = fuse_ctl_add_conn(fc); 1048 if (err) 1049 goto err_unlock; 1050 1051 list_add_tail(&fc->entry, &fuse_conn_list); 1052 sb->s_root = root_dentry; 1053 fc->connected = 1; 1054 file->private_data = fuse_conn_get(fc); 1055 mutex_unlock(&fuse_mutex); 1056 /* 1057 * atomic_dec_and_test() in fput() provides the necessary 1058 * memory barrier for file->private_data to be visible on all 1059 * CPUs after this 1060 */ 1061 fput(file); 1062 1063 fuse_send_init(fc, init_req); 1064 1065 return 0; 1066 1067 err_unlock: 1068 mutex_unlock(&fuse_mutex); 1069 err_free_init_req: 1070 fuse_request_free(init_req); 1071 err_put_root: 1072 dput(root_dentry); 1073 err_put_conn: 1074 fuse_bdi_destroy(fc); 1075 fuse_conn_put(fc); 1076 err_fput: 1077 fput(file); 1078 err: 1079 return err; 1080 } 1081 1082 static struct dentry *fuse_mount(struct file_system_type *fs_type, 1083 int flags, const char *dev_name, 1084 void *raw_data) 1085 { 1086 return mount_nodev(fs_type, flags, raw_data, fuse_fill_super); 1087 } 1088 1089 static void fuse_kill_sb_anon(struct super_block *sb) 1090 { 1091 struct fuse_conn *fc = get_fuse_conn_super(sb); 1092 1093 if (fc) { 1094 down_write(&fc->killsb); 1095 fc->sb = NULL; 1096 up_write(&fc->killsb); 1097 } 1098 1099 kill_anon_super(sb); 1100 } 1101 1102 static struct file_system_type fuse_fs_type = { 1103 .owner = THIS_MODULE, 1104 .name = "fuse", 1105 .fs_flags = FS_HAS_SUBTYPE, 1106 .mount = fuse_mount, 1107 .kill_sb = fuse_kill_sb_anon, 1108 }; 1109 1110 #ifdef CONFIG_BLOCK 1111 static struct dentry *fuse_mount_blk(struct file_system_type *fs_type, 1112 int flags, const char *dev_name, 1113 void *raw_data) 1114 { 1115 return mount_bdev(fs_type, flags, dev_name, raw_data, fuse_fill_super); 1116 } 1117 1118 static void fuse_kill_sb_blk(struct super_block *sb) 1119 { 1120 struct fuse_conn *fc = get_fuse_conn_super(sb); 1121 1122 if (fc) { 1123 down_write(&fc->killsb); 1124 fc->sb = NULL; 1125 up_write(&fc->killsb); 1126 } 1127 1128 kill_block_super(sb); 1129 } 1130 1131 static struct file_system_type fuseblk_fs_type = { 1132 .owner = THIS_MODULE, 1133 .name = "fuseblk", 1134 .mount = fuse_mount_blk, 1135 .kill_sb = fuse_kill_sb_blk, 1136 .fs_flags = FS_REQUIRES_DEV | FS_HAS_SUBTYPE, 1137 }; 1138 1139 static inline int register_fuseblk(void) 1140 { 1141 return register_filesystem(&fuseblk_fs_type); 1142 } 1143 1144 static inline void unregister_fuseblk(void) 1145 { 1146 unregister_filesystem(&fuseblk_fs_type); 1147 } 1148 #else 1149 static inline int register_fuseblk(void) 1150 { 1151 return 0; 1152 } 1153 1154 static inline void unregister_fuseblk(void) 1155 { 1156 } 1157 #endif 1158 1159 static void fuse_inode_init_once(void *foo) 1160 { 1161 struct inode *inode = foo; 1162 1163 inode_init_once(inode); 1164 } 1165 1166 static int __init fuse_fs_init(void) 1167 { 1168 int err; 1169 1170 fuse_inode_cachep = kmem_cache_create("fuse_inode", 1171 sizeof(struct fuse_inode), 1172 0, SLAB_HWCACHE_ALIGN, 1173 fuse_inode_init_once); 1174 err = -ENOMEM; 1175 if (!fuse_inode_cachep) 1176 goto out; 1177 1178 err = register_fuseblk(); 1179 if (err) 1180 goto out2; 1181 1182 err = register_filesystem(&fuse_fs_type); 1183 if (err) 1184 goto out3; 1185 1186 return 0; 1187 1188 out3: 1189 unregister_fuseblk(); 1190 out2: 1191 kmem_cache_destroy(fuse_inode_cachep); 1192 out: 1193 return err; 1194 } 1195 1196 static void fuse_fs_cleanup(void) 1197 { 1198 unregister_filesystem(&fuse_fs_type); 1199 unregister_fuseblk(); 1200 1201 /* 1202 * Make sure all delayed rcu free inodes are flushed before we 1203 * destroy cache. 1204 */ 1205 rcu_barrier(); 1206 kmem_cache_destroy(fuse_inode_cachep); 1207 } 1208 1209 static struct kobject *fuse_kobj; 1210 static struct kobject *connections_kobj; 1211 1212 static int fuse_sysfs_init(void) 1213 { 1214 int err; 1215 1216 fuse_kobj = kobject_create_and_add("fuse", fs_kobj); 1217 if (!fuse_kobj) { 1218 err = -ENOMEM; 1219 goto out_err; 1220 } 1221 1222 connections_kobj = kobject_create_and_add("connections", fuse_kobj); 1223 if (!connections_kobj) { 1224 err = -ENOMEM; 1225 goto out_fuse_unregister; 1226 } 1227 1228 return 0; 1229 1230 out_fuse_unregister: 1231 kobject_put(fuse_kobj); 1232 out_err: 1233 return err; 1234 } 1235 1236 static void fuse_sysfs_cleanup(void) 1237 { 1238 kobject_put(connections_kobj); 1239 kobject_put(fuse_kobj); 1240 } 1241 1242 static int __init fuse_init(void) 1243 { 1244 int res; 1245 1246 printk(KERN_INFO "fuse init (API version %i.%i)\n", 1247 FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION); 1248 1249 INIT_LIST_HEAD(&fuse_conn_list); 1250 res = fuse_fs_init(); 1251 if (res) 1252 goto err; 1253 1254 res = fuse_dev_init(); 1255 if (res) 1256 goto err_fs_cleanup; 1257 1258 res = fuse_sysfs_init(); 1259 if (res) 1260 goto err_dev_cleanup; 1261 1262 res = fuse_ctl_init(); 1263 if (res) 1264 goto err_sysfs_cleanup; 1265 1266 sanitize_global_limit(&max_user_bgreq); 1267 sanitize_global_limit(&max_user_congthresh); 1268 1269 return 0; 1270 1271 err_sysfs_cleanup: 1272 fuse_sysfs_cleanup(); 1273 err_dev_cleanup: 1274 fuse_dev_cleanup(); 1275 err_fs_cleanup: 1276 fuse_fs_cleanup(); 1277 err: 1278 return res; 1279 } 1280 1281 static void __exit fuse_exit(void) 1282 { 1283 printk(KERN_DEBUG "fuse exit\n"); 1284 1285 fuse_ctl_cleanup(); 1286 fuse_sysfs_cleanup(); 1287 fuse_fs_cleanup(); 1288 fuse_dev_cleanup(); 1289 } 1290 1291 module_init(fuse_init); 1292 module_exit(fuse_exit); 1293