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