1 /* 2 FUSE: Filesystem in Userspace 3 Copyright (C) 2001-2008 Miklos Szeredi <miklos@szeredi.hu> 4 5 This program can be distributed under the terms of the GNU GPL. 6 See the file COPYING. 7 */ 8 9 #include "fuse_i.h" 10 11 #include <linux/pagemap.h> 12 #include <linux/slab.h> 13 #include <linux/file.h> 14 #include <linux/seq_file.h> 15 #include <linux/init.h> 16 #include <linux/module.h> 17 #include <linux/moduleparam.h> 18 #include <linux/parser.h> 19 #include <linux/statfs.h> 20 #include <linux/random.h> 21 #include <linux/sched.h> 22 #include <linux/exportfs.h> 23 24 MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>"); 25 MODULE_DESCRIPTION("Filesystem in Userspace"); 26 MODULE_LICENSE("GPL"); 27 28 static struct kmem_cache *fuse_inode_cachep; 29 struct list_head fuse_conn_list; 30 DEFINE_MUTEX(fuse_mutex); 31 32 static int set_global_limit(const char *val, struct kernel_param *kp); 33 34 unsigned max_user_bgreq; 35 module_param_call(max_user_bgreq, set_global_limit, param_get_uint, 36 &max_user_bgreq, 0644); 37 __MODULE_PARM_TYPE(max_user_bgreq, "uint"); 38 MODULE_PARM_DESC(max_user_bgreq, 39 "Global limit for the maximum number of backgrounded requests an " 40 "unprivileged user can set"); 41 42 unsigned max_user_congthresh; 43 module_param_call(max_user_congthresh, set_global_limit, param_get_uint, 44 &max_user_congthresh, 0644); 45 __MODULE_PARM_TYPE(max_user_congthresh, "uint"); 46 MODULE_PARM_DESC(max_user_congthresh, 47 "Global limit for the maximum congestion threshold an " 48 "unprivileged user can set"); 49 50 #define FUSE_SUPER_MAGIC 0x65735546 51 52 #define FUSE_DEFAULT_BLKSIZE 512 53 54 /** Maximum number of outstanding background requests */ 55 #define FUSE_DEFAULT_MAX_BACKGROUND 12 56 57 /** Congestion starts at 75% of maximum */ 58 #define FUSE_DEFAULT_CONGESTION_THRESHOLD (FUSE_DEFAULT_MAX_BACKGROUND * 3 / 4) 59 60 struct fuse_mount_data { 61 int fd; 62 unsigned rootmode; 63 kuid_t user_id; 64 kgid_t group_id; 65 unsigned fd_present:1; 66 unsigned rootmode_present:1; 67 unsigned user_id_present:1; 68 unsigned group_id_present:1; 69 unsigned flags; 70 unsigned max_read; 71 unsigned blksize; 72 }; 73 74 struct fuse_forget_link *fuse_alloc_forget(void) 75 { 76 return kzalloc(sizeof(struct fuse_forget_link), GFP_KERNEL); 77 } 78 79 static struct inode *fuse_alloc_inode(struct super_block *sb) 80 { 81 struct inode *inode; 82 struct fuse_inode *fi; 83 84 inode = kmem_cache_alloc(fuse_inode_cachep, GFP_KERNEL); 85 if (!inode) 86 return NULL; 87 88 fi = get_fuse_inode(inode); 89 fi->i_time = 0; 90 fi->nodeid = 0; 91 fi->nlookup = 0; 92 fi->attr_version = 0; 93 fi->writectr = 0; 94 fi->orig_ino = 0; 95 fi->state = 0; 96 INIT_LIST_HEAD(&fi->write_files); 97 INIT_LIST_HEAD(&fi->queued_writes); 98 INIT_LIST_HEAD(&fi->writepages); 99 init_waitqueue_head(&fi->page_waitq); 100 fi->forget = fuse_alloc_forget(); 101 if (!fi->forget) { 102 kmem_cache_free(fuse_inode_cachep, inode); 103 return NULL; 104 } 105 106 return inode; 107 } 108 109 static void fuse_i_callback(struct rcu_head *head) 110 { 111 struct inode *inode = container_of(head, struct inode, i_rcu); 112 kmem_cache_free(fuse_inode_cachep, inode); 113 } 114 115 static void fuse_destroy_inode(struct inode *inode) 116 { 117 struct fuse_inode *fi = get_fuse_inode(inode); 118 BUG_ON(!list_empty(&fi->write_files)); 119 BUG_ON(!list_empty(&fi->queued_writes)); 120 kfree(fi->forget); 121 call_rcu(&inode->i_rcu, fuse_i_callback); 122 } 123 124 static void fuse_evict_inode(struct inode *inode) 125 { 126 truncate_inode_pages_final(&inode->i_data); 127 clear_inode(inode); 128 if (inode->i_sb->s_flags & MS_ACTIVE) { 129 struct fuse_conn *fc = get_fuse_conn(inode); 130 struct fuse_inode *fi = get_fuse_inode(inode); 131 fuse_queue_forget(fc, fi->forget, fi->nodeid, fi->nlookup); 132 fi->forget = NULL; 133 } 134 } 135 136 static int fuse_remount_fs(struct super_block *sb, int *flags, char *data) 137 { 138 sync_filesystem(sb); 139 if (*flags & MS_MANDLOCK) 140 return -EINVAL; 141 142 return 0; 143 } 144 145 /* 146 * ino_t is 32-bits on 32-bit arch. We have to squash the 64-bit value down 147 * so that it will fit. 148 */ 149 static ino_t fuse_squash_ino(u64 ino64) 150 { 151 ino_t ino = (ino_t) ino64; 152 if (sizeof(ino_t) < sizeof(u64)) 153 ino ^= ino64 >> (sizeof(u64) - sizeof(ino_t)) * 8; 154 return ino; 155 } 156 157 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr, 158 u64 attr_valid) 159 { 160 struct fuse_conn *fc = get_fuse_conn(inode); 161 struct fuse_inode *fi = get_fuse_inode(inode); 162 163 fi->attr_version = ++fc->attr_version; 164 fi->i_time = attr_valid; 165 166 inode->i_ino = fuse_squash_ino(attr->ino); 167 inode->i_mode = (inode->i_mode & S_IFMT) | (attr->mode & 07777); 168 set_nlink(inode, attr->nlink); 169 inode->i_uid = make_kuid(&init_user_ns, attr->uid); 170 inode->i_gid = make_kgid(&init_user_ns, attr->gid); 171 inode->i_blocks = attr->blocks; 172 inode->i_atime.tv_sec = attr->atime; 173 inode->i_atime.tv_nsec = attr->atimensec; 174 /* mtime from server may be stale due to local buffered write */ 175 if (!fc->writeback_cache || !S_ISREG(inode->i_mode)) { 176 inode->i_mtime.tv_sec = attr->mtime; 177 inode->i_mtime.tv_nsec = attr->mtimensec; 178 inode->i_ctime.tv_sec = attr->ctime; 179 inode->i_ctime.tv_nsec = attr->ctimensec; 180 } 181 182 if (attr->blksize != 0) 183 inode->i_blkbits = ilog2(attr->blksize); 184 else 185 inode->i_blkbits = inode->i_sb->s_blocksize_bits; 186 187 /* 188 * Don't set the sticky bit in i_mode, unless we want the VFS 189 * to check permissions. This prevents failures due to the 190 * check in may_delete(). 191 */ 192 fi->orig_i_mode = inode->i_mode; 193 if (!(fc->flags & FUSE_DEFAULT_PERMISSIONS)) 194 inode->i_mode &= ~S_ISVTX; 195 196 fi->orig_ino = attr->ino; 197 } 198 199 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr, 200 u64 attr_valid, u64 attr_version) 201 { 202 struct fuse_conn *fc = get_fuse_conn(inode); 203 struct fuse_inode *fi = get_fuse_inode(inode); 204 bool is_wb = fc->writeback_cache; 205 loff_t oldsize; 206 struct timespec old_mtime; 207 208 spin_lock(&fc->lock); 209 if ((attr_version != 0 && fi->attr_version > attr_version) || 210 test_bit(FUSE_I_SIZE_UNSTABLE, &fi->state)) { 211 spin_unlock(&fc->lock); 212 return; 213 } 214 215 old_mtime = inode->i_mtime; 216 fuse_change_attributes_common(inode, attr, attr_valid); 217 218 oldsize = inode->i_size; 219 /* 220 * In case of writeback_cache enabled, the cached writes beyond EOF 221 * extend local i_size without keeping userspace server in sync. So, 222 * attr->size coming from server can be stale. We cannot trust it. 223 */ 224 if (!is_wb || !S_ISREG(inode->i_mode)) 225 i_size_write(inode, attr->size); 226 spin_unlock(&fc->lock); 227 228 if (!is_wb && S_ISREG(inode->i_mode)) { 229 bool inval = false; 230 231 if (oldsize != attr->size) { 232 truncate_pagecache(inode, attr->size); 233 inval = true; 234 } else if (fc->auto_inval_data) { 235 struct timespec new_mtime = { 236 .tv_sec = attr->mtime, 237 .tv_nsec = attr->mtimensec, 238 }; 239 240 /* 241 * Auto inval mode also checks and invalidates if mtime 242 * has changed. 243 */ 244 if (!timespec_equal(&old_mtime, &new_mtime)) 245 inval = true; 246 } 247 248 if (inval) 249 invalidate_inode_pages2(inode->i_mapping); 250 } 251 } 252 253 static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr) 254 { 255 inode->i_mode = attr->mode & S_IFMT; 256 inode->i_size = attr->size; 257 inode->i_mtime.tv_sec = attr->mtime; 258 inode->i_mtime.tv_nsec = attr->mtimensec; 259 inode->i_ctime.tv_sec = attr->ctime; 260 inode->i_ctime.tv_nsec = attr->ctimensec; 261 if (S_ISREG(inode->i_mode)) { 262 fuse_init_common(inode); 263 fuse_init_file_inode(inode); 264 } else if (S_ISDIR(inode->i_mode)) 265 fuse_init_dir(inode); 266 else if (S_ISLNK(inode->i_mode)) 267 fuse_init_symlink(inode); 268 else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) || 269 S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) { 270 fuse_init_common(inode); 271 init_special_inode(inode, inode->i_mode, 272 new_decode_dev(attr->rdev)); 273 } else 274 BUG(); 275 } 276 277 int fuse_inode_eq(struct inode *inode, void *_nodeidp) 278 { 279 u64 nodeid = *(u64 *) _nodeidp; 280 if (get_node_id(inode) == nodeid) 281 return 1; 282 else 283 return 0; 284 } 285 286 static int fuse_inode_set(struct inode *inode, void *_nodeidp) 287 { 288 u64 nodeid = *(u64 *) _nodeidp; 289 get_fuse_inode(inode)->nodeid = nodeid; 290 return 0; 291 } 292 293 struct inode *fuse_iget(struct super_block *sb, u64 nodeid, 294 int generation, struct fuse_attr *attr, 295 u64 attr_valid, u64 attr_version) 296 { 297 struct inode *inode; 298 struct fuse_inode *fi; 299 struct fuse_conn *fc = get_fuse_conn_super(sb); 300 301 retry: 302 inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid); 303 if (!inode) 304 return NULL; 305 306 if ((inode->i_state & I_NEW)) { 307 inode->i_flags |= S_NOATIME; 308 if (!fc->writeback_cache || !S_ISREG(attr->mode)) 309 inode->i_flags |= S_NOCMTIME; 310 inode->i_generation = generation; 311 inode->i_data.backing_dev_info = &fc->bdi; 312 fuse_init_inode(inode, attr); 313 unlock_new_inode(inode); 314 } else if ((inode->i_mode ^ attr->mode) & S_IFMT) { 315 /* Inode has changed type, any I/O on the old should fail */ 316 make_bad_inode(inode); 317 iput(inode); 318 goto retry; 319 } 320 321 fi = get_fuse_inode(inode); 322 spin_lock(&fc->lock); 323 fi->nlookup++; 324 spin_unlock(&fc->lock); 325 fuse_change_attributes(inode, attr, attr_valid, attr_version); 326 327 return inode; 328 } 329 330 int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid, 331 loff_t offset, loff_t len) 332 { 333 struct inode *inode; 334 pgoff_t pg_start; 335 pgoff_t pg_end; 336 337 inode = ilookup5(sb, nodeid, fuse_inode_eq, &nodeid); 338 if (!inode) 339 return -ENOENT; 340 341 fuse_invalidate_attr(inode); 342 if (offset >= 0) { 343 pg_start = offset >> PAGE_CACHE_SHIFT; 344 if (len <= 0) 345 pg_end = -1; 346 else 347 pg_end = (offset + len - 1) >> PAGE_CACHE_SHIFT; 348 invalidate_inode_pages2_range(inode->i_mapping, 349 pg_start, pg_end); 350 } 351 iput(inode); 352 return 0; 353 } 354 355 static void fuse_umount_begin(struct super_block *sb) 356 { 357 fuse_abort_conn(get_fuse_conn_super(sb)); 358 } 359 360 static void fuse_send_destroy(struct fuse_conn *fc) 361 { 362 struct fuse_req *req = fc->destroy_req; 363 if (req && fc->conn_init) { 364 fc->destroy_req = NULL; 365 req->in.h.opcode = FUSE_DESTROY; 366 req->force = 1; 367 req->background = 0; 368 fuse_request_send(fc, req); 369 fuse_put_request(fc, req); 370 } 371 } 372 373 static void fuse_bdi_destroy(struct fuse_conn *fc) 374 { 375 if (fc->bdi_initialized) 376 bdi_destroy(&fc->bdi); 377 } 378 379 void fuse_conn_kill(struct fuse_conn *fc) 380 { 381 spin_lock(&fc->lock); 382 fc->connected = 0; 383 fc->blocked = 0; 384 fc->initialized = 1; 385 spin_unlock(&fc->lock); 386 /* Flush all readers on this fs */ 387 kill_fasync(&fc->fasync, SIGIO, POLL_IN); 388 wake_up_all(&fc->waitq); 389 wake_up_all(&fc->blocked_waitq); 390 wake_up_all(&fc->reserved_req_waitq); 391 } 392 EXPORT_SYMBOL_GPL(fuse_conn_kill); 393 394 static void fuse_put_super(struct super_block *sb) 395 { 396 struct fuse_conn *fc = get_fuse_conn_super(sb); 397 398 fuse_send_destroy(fc); 399 400 fuse_conn_kill(fc); 401 mutex_lock(&fuse_mutex); 402 list_del(&fc->entry); 403 fuse_ctl_remove_conn(fc); 404 mutex_unlock(&fuse_mutex); 405 fuse_bdi_destroy(fc); 406 407 fuse_conn_put(fc); 408 } 409 410 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr) 411 { 412 stbuf->f_type = FUSE_SUPER_MAGIC; 413 stbuf->f_bsize = attr->bsize; 414 stbuf->f_frsize = attr->frsize; 415 stbuf->f_blocks = attr->blocks; 416 stbuf->f_bfree = attr->bfree; 417 stbuf->f_bavail = attr->bavail; 418 stbuf->f_files = attr->files; 419 stbuf->f_ffree = attr->ffree; 420 stbuf->f_namelen = attr->namelen; 421 /* fsid is left zero */ 422 } 423 424 static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf) 425 { 426 struct super_block *sb = dentry->d_sb; 427 struct fuse_conn *fc = get_fuse_conn_super(sb); 428 struct fuse_req *req; 429 struct fuse_statfs_out outarg; 430 int err; 431 432 if (!fuse_allow_current_process(fc)) { 433 buf->f_type = FUSE_SUPER_MAGIC; 434 return 0; 435 } 436 437 req = fuse_get_req_nopages(fc); 438 if (IS_ERR(req)) 439 return PTR_ERR(req); 440 441 memset(&outarg, 0, sizeof(outarg)); 442 req->in.numargs = 0; 443 req->in.h.opcode = FUSE_STATFS; 444 req->in.h.nodeid = get_node_id(dentry->d_inode); 445 req->out.numargs = 1; 446 req->out.args[0].size = 447 fc->minor < 4 ? FUSE_COMPAT_STATFS_SIZE : sizeof(outarg); 448 req->out.args[0].value = &outarg; 449 fuse_request_send(fc, req); 450 err = req->out.h.error; 451 if (!err) 452 convert_fuse_statfs(buf, &outarg.st); 453 fuse_put_request(fc, req); 454 return err; 455 } 456 457 enum { 458 OPT_FD, 459 OPT_ROOTMODE, 460 OPT_USER_ID, 461 OPT_GROUP_ID, 462 OPT_DEFAULT_PERMISSIONS, 463 OPT_ALLOW_OTHER, 464 OPT_MAX_READ, 465 OPT_BLKSIZE, 466 OPT_ERR 467 }; 468 469 static const match_table_t tokens = { 470 {OPT_FD, "fd=%u"}, 471 {OPT_ROOTMODE, "rootmode=%o"}, 472 {OPT_USER_ID, "user_id=%u"}, 473 {OPT_GROUP_ID, "group_id=%u"}, 474 {OPT_DEFAULT_PERMISSIONS, "default_permissions"}, 475 {OPT_ALLOW_OTHER, "allow_other"}, 476 {OPT_MAX_READ, "max_read=%u"}, 477 {OPT_BLKSIZE, "blksize=%u"}, 478 {OPT_ERR, NULL} 479 }; 480 481 static int parse_fuse_opt(char *opt, struct fuse_mount_data *d, int is_bdev) 482 { 483 char *p; 484 memset(d, 0, sizeof(struct fuse_mount_data)); 485 d->max_read = ~0; 486 d->blksize = FUSE_DEFAULT_BLKSIZE; 487 488 while ((p = strsep(&opt, ",")) != NULL) { 489 int token; 490 int value; 491 substring_t args[MAX_OPT_ARGS]; 492 if (!*p) 493 continue; 494 495 token = match_token(p, tokens, args); 496 switch (token) { 497 case OPT_FD: 498 if (match_int(&args[0], &value)) 499 return 0; 500 d->fd = value; 501 d->fd_present = 1; 502 break; 503 504 case OPT_ROOTMODE: 505 if (match_octal(&args[0], &value)) 506 return 0; 507 if (!fuse_valid_type(value)) 508 return 0; 509 d->rootmode = value; 510 d->rootmode_present = 1; 511 break; 512 513 case OPT_USER_ID: 514 if (match_int(&args[0], &value)) 515 return 0; 516 d->user_id = make_kuid(current_user_ns(), value); 517 if (!uid_valid(d->user_id)) 518 return 0; 519 d->user_id_present = 1; 520 break; 521 522 case OPT_GROUP_ID: 523 if (match_int(&args[0], &value)) 524 return 0; 525 d->group_id = make_kgid(current_user_ns(), value); 526 if (!gid_valid(d->group_id)) 527 return 0; 528 d->group_id_present = 1; 529 break; 530 531 case OPT_DEFAULT_PERMISSIONS: 532 d->flags |= FUSE_DEFAULT_PERMISSIONS; 533 break; 534 535 case OPT_ALLOW_OTHER: 536 d->flags |= FUSE_ALLOW_OTHER; 537 break; 538 539 case OPT_MAX_READ: 540 if (match_int(&args[0], &value)) 541 return 0; 542 d->max_read = value; 543 break; 544 545 case OPT_BLKSIZE: 546 if (!is_bdev || match_int(&args[0], &value)) 547 return 0; 548 d->blksize = value; 549 break; 550 551 default: 552 return 0; 553 } 554 } 555 556 if (!d->fd_present || !d->rootmode_present || 557 !d->user_id_present || !d->group_id_present) 558 return 0; 559 560 return 1; 561 } 562 563 static int fuse_show_options(struct seq_file *m, struct dentry *root) 564 { 565 struct super_block *sb = root->d_sb; 566 struct fuse_conn *fc = get_fuse_conn_super(sb); 567 568 seq_printf(m, ",user_id=%u", from_kuid_munged(&init_user_ns, fc->user_id)); 569 seq_printf(m, ",group_id=%u", from_kgid_munged(&init_user_ns, fc->group_id)); 570 if (fc->flags & FUSE_DEFAULT_PERMISSIONS) 571 seq_puts(m, ",default_permissions"); 572 if (fc->flags & FUSE_ALLOW_OTHER) 573 seq_puts(m, ",allow_other"); 574 if (fc->max_read != ~0) 575 seq_printf(m, ",max_read=%u", fc->max_read); 576 if (sb->s_bdev && sb->s_blocksize != FUSE_DEFAULT_BLKSIZE) 577 seq_printf(m, ",blksize=%lu", sb->s_blocksize); 578 return 0; 579 } 580 581 void fuse_conn_init(struct fuse_conn *fc) 582 { 583 memset(fc, 0, sizeof(*fc)); 584 spin_lock_init(&fc->lock); 585 init_rwsem(&fc->killsb); 586 atomic_set(&fc->count, 1); 587 init_waitqueue_head(&fc->waitq); 588 init_waitqueue_head(&fc->blocked_waitq); 589 init_waitqueue_head(&fc->reserved_req_waitq); 590 INIT_LIST_HEAD(&fc->pending); 591 INIT_LIST_HEAD(&fc->processing); 592 INIT_LIST_HEAD(&fc->io); 593 INIT_LIST_HEAD(&fc->interrupts); 594 INIT_LIST_HEAD(&fc->bg_queue); 595 INIT_LIST_HEAD(&fc->entry); 596 fc->forget_list_tail = &fc->forget_list_head; 597 atomic_set(&fc->num_waiting, 0); 598 fc->max_background = FUSE_DEFAULT_MAX_BACKGROUND; 599 fc->congestion_threshold = FUSE_DEFAULT_CONGESTION_THRESHOLD; 600 fc->khctr = 0; 601 fc->polled_files = RB_ROOT; 602 fc->reqctr = 0; 603 fc->blocked = 0; 604 fc->initialized = 0; 605 fc->attr_version = 1; 606 get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key)); 607 } 608 EXPORT_SYMBOL_GPL(fuse_conn_init); 609 610 void fuse_conn_put(struct fuse_conn *fc) 611 { 612 if (atomic_dec_and_test(&fc->count)) { 613 if (fc->destroy_req) 614 fuse_request_free(fc->destroy_req); 615 fc->release(fc); 616 } 617 } 618 EXPORT_SYMBOL_GPL(fuse_conn_put); 619 620 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc) 621 { 622 atomic_inc(&fc->count); 623 return fc; 624 } 625 EXPORT_SYMBOL_GPL(fuse_conn_get); 626 627 static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned mode) 628 { 629 struct fuse_attr attr; 630 memset(&attr, 0, sizeof(attr)); 631 632 attr.mode = mode; 633 attr.ino = FUSE_ROOT_ID; 634 attr.nlink = 1; 635 return fuse_iget(sb, 1, 0, &attr, 0, 0); 636 } 637 638 struct fuse_inode_handle { 639 u64 nodeid; 640 u32 generation; 641 }; 642 643 static struct dentry *fuse_get_dentry(struct super_block *sb, 644 struct fuse_inode_handle *handle) 645 { 646 struct fuse_conn *fc = get_fuse_conn_super(sb); 647 struct inode *inode; 648 struct dentry *entry; 649 int err = -ESTALE; 650 651 if (handle->nodeid == 0) 652 goto out_err; 653 654 inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid); 655 if (!inode) { 656 struct fuse_entry_out outarg; 657 struct qstr name; 658 659 if (!fc->export_support) 660 goto out_err; 661 662 name.len = 1; 663 name.name = "."; 664 err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg, 665 &inode); 666 if (err && err != -ENOENT) 667 goto out_err; 668 if (err || !inode) { 669 err = -ESTALE; 670 goto out_err; 671 } 672 err = -EIO; 673 if (get_node_id(inode) != handle->nodeid) 674 goto out_iput; 675 } 676 err = -ESTALE; 677 if (inode->i_generation != handle->generation) 678 goto out_iput; 679 680 entry = d_obtain_alias(inode); 681 if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID) 682 fuse_invalidate_entry_cache(entry); 683 684 return entry; 685 686 out_iput: 687 iput(inode); 688 out_err: 689 return ERR_PTR(err); 690 } 691 692 static int fuse_encode_fh(struct inode *inode, u32 *fh, int *max_len, 693 struct inode *parent) 694 { 695 int len = parent ? 6 : 3; 696 u64 nodeid; 697 u32 generation; 698 699 if (*max_len < len) { 700 *max_len = len; 701 return FILEID_INVALID; 702 } 703 704 nodeid = get_fuse_inode(inode)->nodeid; 705 generation = inode->i_generation; 706 707 fh[0] = (u32)(nodeid >> 32); 708 fh[1] = (u32)(nodeid & 0xffffffff); 709 fh[2] = generation; 710 711 if (parent) { 712 nodeid = get_fuse_inode(parent)->nodeid; 713 generation = parent->i_generation; 714 715 fh[3] = (u32)(nodeid >> 32); 716 fh[4] = (u32)(nodeid & 0xffffffff); 717 fh[5] = generation; 718 } 719 720 *max_len = len; 721 return parent ? 0x82 : 0x81; 722 } 723 724 static struct dentry *fuse_fh_to_dentry(struct super_block *sb, 725 struct fid *fid, int fh_len, int fh_type) 726 { 727 struct fuse_inode_handle handle; 728 729 if ((fh_type != 0x81 && fh_type != 0x82) || fh_len < 3) 730 return NULL; 731 732 handle.nodeid = (u64) fid->raw[0] << 32; 733 handle.nodeid |= (u64) fid->raw[1]; 734 handle.generation = fid->raw[2]; 735 return fuse_get_dentry(sb, &handle); 736 } 737 738 static struct dentry *fuse_fh_to_parent(struct super_block *sb, 739 struct fid *fid, int fh_len, int fh_type) 740 { 741 struct fuse_inode_handle parent; 742 743 if (fh_type != 0x82 || fh_len < 6) 744 return NULL; 745 746 parent.nodeid = (u64) fid->raw[3] << 32; 747 parent.nodeid |= (u64) fid->raw[4]; 748 parent.generation = fid->raw[5]; 749 return fuse_get_dentry(sb, &parent); 750 } 751 752 static struct dentry *fuse_get_parent(struct dentry *child) 753 { 754 struct inode *child_inode = child->d_inode; 755 struct fuse_conn *fc = get_fuse_conn(child_inode); 756 struct inode *inode; 757 struct dentry *parent; 758 struct fuse_entry_out outarg; 759 struct qstr name; 760 int err; 761 762 if (!fc->export_support) 763 return ERR_PTR(-ESTALE); 764 765 name.len = 2; 766 name.name = ".."; 767 err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode), 768 &name, &outarg, &inode); 769 if (err) { 770 if (err == -ENOENT) 771 return ERR_PTR(-ESTALE); 772 return ERR_PTR(err); 773 } 774 775 parent = d_obtain_alias(inode); 776 if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID) 777 fuse_invalidate_entry_cache(parent); 778 779 return parent; 780 } 781 782 static const struct export_operations fuse_export_operations = { 783 .fh_to_dentry = fuse_fh_to_dentry, 784 .fh_to_parent = fuse_fh_to_parent, 785 .encode_fh = fuse_encode_fh, 786 .get_parent = fuse_get_parent, 787 }; 788 789 static const struct super_operations fuse_super_operations = { 790 .alloc_inode = fuse_alloc_inode, 791 .destroy_inode = fuse_destroy_inode, 792 .evict_inode = fuse_evict_inode, 793 .write_inode = fuse_write_inode, 794 .drop_inode = generic_delete_inode, 795 .remount_fs = fuse_remount_fs, 796 .put_super = fuse_put_super, 797 .umount_begin = fuse_umount_begin, 798 .statfs = fuse_statfs, 799 .show_options = fuse_show_options, 800 }; 801 802 static void sanitize_global_limit(unsigned *limit) 803 { 804 if (*limit == 0) 805 *limit = ((totalram_pages << PAGE_SHIFT) >> 13) / 806 sizeof(struct fuse_req); 807 808 if (*limit >= 1 << 16) 809 *limit = (1 << 16) - 1; 810 } 811 812 static int set_global_limit(const char *val, struct kernel_param *kp) 813 { 814 int rv; 815 816 rv = param_set_uint(val, kp); 817 if (rv) 818 return rv; 819 820 sanitize_global_limit((unsigned *)kp->arg); 821 822 return 0; 823 } 824 825 static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg) 826 { 827 int cap_sys_admin = capable(CAP_SYS_ADMIN); 828 829 if (arg->minor < 13) 830 return; 831 832 sanitize_global_limit(&max_user_bgreq); 833 sanitize_global_limit(&max_user_congthresh); 834 835 if (arg->max_background) { 836 fc->max_background = arg->max_background; 837 838 if (!cap_sys_admin && fc->max_background > max_user_bgreq) 839 fc->max_background = max_user_bgreq; 840 } 841 if (arg->congestion_threshold) { 842 fc->congestion_threshold = arg->congestion_threshold; 843 844 if (!cap_sys_admin && 845 fc->congestion_threshold > max_user_congthresh) 846 fc->congestion_threshold = max_user_congthresh; 847 } 848 } 849 850 static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req) 851 { 852 struct fuse_init_out *arg = &req->misc.init_out; 853 854 if (req->out.h.error || arg->major != FUSE_KERNEL_VERSION) 855 fc->conn_error = 1; 856 else { 857 unsigned long ra_pages; 858 859 process_init_limits(fc, arg); 860 861 if (arg->minor >= 6) { 862 ra_pages = arg->max_readahead / PAGE_CACHE_SIZE; 863 if (arg->flags & FUSE_ASYNC_READ) 864 fc->async_read = 1; 865 if (!(arg->flags & FUSE_POSIX_LOCKS)) 866 fc->no_lock = 1; 867 if (arg->minor >= 17) { 868 if (!(arg->flags & FUSE_FLOCK_LOCKS)) 869 fc->no_flock = 1; 870 } else { 871 if (!(arg->flags & FUSE_POSIX_LOCKS)) 872 fc->no_flock = 1; 873 } 874 if (arg->flags & FUSE_ATOMIC_O_TRUNC) 875 fc->atomic_o_trunc = 1; 876 if (arg->minor >= 9) { 877 /* LOOKUP has dependency on proto version */ 878 if (arg->flags & FUSE_EXPORT_SUPPORT) 879 fc->export_support = 1; 880 } 881 if (arg->flags & FUSE_BIG_WRITES) 882 fc->big_writes = 1; 883 if (arg->flags & FUSE_DONT_MASK) 884 fc->dont_mask = 1; 885 if (arg->flags & FUSE_AUTO_INVAL_DATA) 886 fc->auto_inval_data = 1; 887 if (arg->flags & FUSE_DO_READDIRPLUS) { 888 fc->do_readdirplus = 1; 889 if (arg->flags & FUSE_READDIRPLUS_AUTO) 890 fc->readdirplus_auto = 1; 891 } 892 if (arg->flags & FUSE_ASYNC_DIO) 893 fc->async_dio = 1; 894 if (arg->flags & FUSE_WRITEBACK_CACHE) 895 fc->writeback_cache = 1; 896 if (arg->time_gran && arg->time_gran <= 1000000000) 897 fc->sb->s_time_gran = arg->time_gran; 898 else 899 fc->sb->s_time_gran = 1000000000; 900 901 } else { 902 ra_pages = fc->max_read / PAGE_CACHE_SIZE; 903 fc->no_lock = 1; 904 fc->no_flock = 1; 905 } 906 907 fc->bdi.ra_pages = min(fc->bdi.ra_pages, ra_pages); 908 fc->minor = arg->minor; 909 fc->max_write = arg->minor < 5 ? 4096 : arg->max_write; 910 fc->max_write = max_t(unsigned, 4096, fc->max_write); 911 fc->conn_init = 1; 912 } 913 fc->initialized = 1; 914 wake_up_all(&fc->blocked_waitq); 915 } 916 917 static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req) 918 { 919 struct fuse_init_in *arg = &req->misc.init_in; 920 921 arg->major = FUSE_KERNEL_VERSION; 922 arg->minor = FUSE_KERNEL_MINOR_VERSION; 923 arg->max_readahead = fc->bdi.ra_pages * PAGE_CACHE_SIZE; 924 arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC | 925 FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK | 926 FUSE_SPLICE_WRITE | FUSE_SPLICE_MOVE | FUSE_SPLICE_READ | 927 FUSE_FLOCK_LOCKS | FUSE_IOCTL_DIR | FUSE_AUTO_INVAL_DATA | 928 FUSE_DO_READDIRPLUS | FUSE_READDIRPLUS_AUTO | FUSE_ASYNC_DIO | 929 FUSE_WRITEBACK_CACHE; 930 req->in.h.opcode = FUSE_INIT; 931 req->in.numargs = 1; 932 req->in.args[0].size = sizeof(*arg); 933 req->in.args[0].value = arg; 934 req->out.numargs = 1; 935 /* Variable length argument used for backward compatibility 936 with interface version < 7.5. Rest of init_out is zeroed 937 by do_get_request(), so a short reply is not a problem */ 938 req->out.argvar = 1; 939 req->out.args[0].size = sizeof(struct fuse_init_out); 940 req->out.args[0].value = &req->misc.init_out; 941 req->end = process_init_reply; 942 fuse_request_send_background(fc, req); 943 } 944 945 static void fuse_free_conn(struct fuse_conn *fc) 946 { 947 kfree_rcu(fc, rcu); 948 } 949 950 static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb) 951 { 952 int err; 953 954 fc->bdi.name = "fuse"; 955 fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE; 956 /* fuse does it's own writeback accounting */ 957 fc->bdi.capabilities = BDI_CAP_NO_ACCT_WB | BDI_CAP_STRICTLIMIT; 958 959 err = bdi_init(&fc->bdi); 960 if (err) 961 return err; 962 963 fc->bdi_initialized = 1; 964 965 if (sb->s_bdev) { 966 err = bdi_register(&fc->bdi, NULL, "%u:%u-fuseblk", 967 MAJOR(fc->dev), MINOR(fc->dev)); 968 } else { 969 err = bdi_register_dev(&fc->bdi, fc->dev); 970 } 971 972 if (err) 973 return err; 974 975 /* 976 * For a single fuse filesystem use max 1% of dirty + 977 * writeback threshold. 978 * 979 * This gives about 1M of write buffer for memory maps on a 980 * machine with 1G and 10% dirty_ratio, which should be more 981 * than enough. 982 * 983 * Privileged users can raise it by writing to 984 * 985 * /sys/class/bdi/<bdi>/max_ratio 986 */ 987 bdi_set_max_ratio(&fc->bdi, 1); 988 989 return 0; 990 } 991 992 static int fuse_fill_super(struct super_block *sb, void *data, int silent) 993 { 994 struct fuse_conn *fc; 995 struct inode *root; 996 struct fuse_mount_data d; 997 struct file *file; 998 struct dentry *root_dentry; 999 struct fuse_req *init_req; 1000 int err; 1001 int is_bdev = sb->s_bdev != NULL; 1002 1003 err = -EINVAL; 1004 if (sb->s_flags & MS_MANDLOCK) 1005 goto err; 1006 1007 sb->s_flags &= ~(MS_NOSEC | MS_I_VERSION); 1008 1009 if (!parse_fuse_opt((char *) data, &d, is_bdev)) 1010 goto err; 1011 1012 if (is_bdev) { 1013 #ifdef CONFIG_BLOCK 1014 err = -EINVAL; 1015 if (!sb_set_blocksize(sb, d.blksize)) 1016 goto err; 1017 #endif 1018 } else { 1019 sb->s_blocksize = PAGE_CACHE_SIZE; 1020 sb->s_blocksize_bits = PAGE_CACHE_SHIFT; 1021 } 1022 sb->s_magic = FUSE_SUPER_MAGIC; 1023 sb->s_op = &fuse_super_operations; 1024 sb->s_maxbytes = MAX_LFS_FILESIZE; 1025 sb->s_time_gran = 1; 1026 sb->s_export_op = &fuse_export_operations; 1027 1028 file = fget(d.fd); 1029 err = -EINVAL; 1030 if (!file) 1031 goto err; 1032 1033 if ((file->f_op != &fuse_dev_operations) || 1034 (file->f_cred->user_ns != &init_user_ns)) 1035 goto err_fput; 1036 1037 fc = kmalloc(sizeof(*fc), GFP_KERNEL); 1038 err = -ENOMEM; 1039 if (!fc) 1040 goto err_fput; 1041 1042 fuse_conn_init(fc); 1043 1044 fc->dev = sb->s_dev; 1045 fc->sb = sb; 1046 err = fuse_bdi_init(fc, sb); 1047 if (err) 1048 goto err_put_conn; 1049 1050 sb->s_bdi = &fc->bdi; 1051 1052 /* Handle umasking inside the fuse code */ 1053 if (sb->s_flags & MS_POSIXACL) 1054 fc->dont_mask = 1; 1055 sb->s_flags |= MS_POSIXACL; 1056 1057 fc->release = fuse_free_conn; 1058 fc->flags = d.flags; 1059 fc->user_id = d.user_id; 1060 fc->group_id = d.group_id; 1061 fc->max_read = max_t(unsigned, 4096, d.max_read); 1062 1063 /* Used by get_root_inode() */ 1064 sb->s_fs_info = fc; 1065 1066 err = -ENOMEM; 1067 root = fuse_get_root_inode(sb, d.rootmode); 1068 root_dentry = d_make_root(root); 1069 if (!root_dentry) 1070 goto err_put_conn; 1071 /* only now - we want root dentry with NULL ->d_op */ 1072 sb->s_d_op = &fuse_dentry_operations; 1073 1074 init_req = fuse_request_alloc(0); 1075 if (!init_req) 1076 goto err_put_root; 1077 init_req->background = 1; 1078 1079 if (is_bdev) { 1080 fc->destroy_req = fuse_request_alloc(0); 1081 if (!fc->destroy_req) 1082 goto err_free_init_req; 1083 } 1084 1085 mutex_lock(&fuse_mutex); 1086 err = -EINVAL; 1087 if (file->private_data) 1088 goto err_unlock; 1089 1090 err = fuse_ctl_add_conn(fc); 1091 if (err) 1092 goto err_unlock; 1093 1094 list_add_tail(&fc->entry, &fuse_conn_list); 1095 sb->s_root = root_dentry; 1096 fc->connected = 1; 1097 file->private_data = fuse_conn_get(fc); 1098 mutex_unlock(&fuse_mutex); 1099 /* 1100 * atomic_dec_and_test() in fput() provides the necessary 1101 * memory barrier for file->private_data to be visible on all 1102 * CPUs after this 1103 */ 1104 fput(file); 1105 1106 fuse_send_init(fc, init_req); 1107 1108 return 0; 1109 1110 err_unlock: 1111 mutex_unlock(&fuse_mutex); 1112 err_free_init_req: 1113 fuse_request_free(init_req); 1114 err_put_root: 1115 dput(root_dentry); 1116 err_put_conn: 1117 fuse_bdi_destroy(fc); 1118 fuse_conn_put(fc); 1119 err_fput: 1120 fput(file); 1121 err: 1122 return err; 1123 } 1124 1125 static struct dentry *fuse_mount(struct file_system_type *fs_type, 1126 int flags, const char *dev_name, 1127 void *raw_data) 1128 { 1129 return mount_nodev(fs_type, flags, raw_data, fuse_fill_super); 1130 } 1131 1132 static void fuse_kill_sb_anon(struct super_block *sb) 1133 { 1134 struct fuse_conn *fc = get_fuse_conn_super(sb); 1135 1136 if (fc) { 1137 down_write(&fc->killsb); 1138 fc->sb = NULL; 1139 up_write(&fc->killsb); 1140 } 1141 1142 kill_anon_super(sb); 1143 } 1144 1145 static struct file_system_type fuse_fs_type = { 1146 .owner = THIS_MODULE, 1147 .name = "fuse", 1148 .fs_flags = FS_HAS_SUBTYPE, 1149 .mount = fuse_mount, 1150 .kill_sb = fuse_kill_sb_anon, 1151 }; 1152 MODULE_ALIAS_FS("fuse"); 1153 1154 #ifdef CONFIG_BLOCK 1155 static struct dentry *fuse_mount_blk(struct file_system_type *fs_type, 1156 int flags, const char *dev_name, 1157 void *raw_data) 1158 { 1159 return mount_bdev(fs_type, flags, dev_name, raw_data, fuse_fill_super); 1160 } 1161 1162 static void fuse_kill_sb_blk(struct super_block *sb) 1163 { 1164 struct fuse_conn *fc = get_fuse_conn_super(sb); 1165 1166 if (fc) { 1167 down_write(&fc->killsb); 1168 fc->sb = NULL; 1169 up_write(&fc->killsb); 1170 } 1171 1172 kill_block_super(sb); 1173 } 1174 1175 static struct file_system_type fuseblk_fs_type = { 1176 .owner = THIS_MODULE, 1177 .name = "fuseblk", 1178 .mount = fuse_mount_blk, 1179 .kill_sb = fuse_kill_sb_blk, 1180 .fs_flags = FS_REQUIRES_DEV | FS_HAS_SUBTYPE, 1181 }; 1182 MODULE_ALIAS_FS("fuseblk"); 1183 1184 static inline int register_fuseblk(void) 1185 { 1186 return register_filesystem(&fuseblk_fs_type); 1187 } 1188 1189 static inline void unregister_fuseblk(void) 1190 { 1191 unregister_filesystem(&fuseblk_fs_type); 1192 } 1193 #else 1194 static inline int register_fuseblk(void) 1195 { 1196 return 0; 1197 } 1198 1199 static inline void unregister_fuseblk(void) 1200 { 1201 } 1202 #endif 1203 1204 static void fuse_inode_init_once(void *foo) 1205 { 1206 struct inode *inode = foo; 1207 1208 inode_init_once(inode); 1209 } 1210 1211 static int __init fuse_fs_init(void) 1212 { 1213 int err; 1214 1215 fuse_inode_cachep = kmem_cache_create("fuse_inode", 1216 sizeof(struct fuse_inode), 1217 0, SLAB_HWCACHE_ALIGN, 1218 fuse_inode_init_once); 1219 err = -ENOMEM; 1220 if (!fuse_inode_cachep) 1221 goto out; 1222 1223 err = register_fuseblk(); 1224 if (err) 1225 goto out2; 1226 1227 err = register_filesystem(&fuse_fs_type); 1228 if (err) 1229 goto out3; 1230 1231 return 0; 1232 1233 out3: 1234 unregister_fuseblk(); 1235 out2: 1236 kmem_cache_destroy(fuse_inode_cachep); 1237 out: 1238 return err; 1239 } 1240 1241 static void fuse_fs_cleanup(void) 1242 { 1243 unregister_filesystem(&fuse_fs_type); 1244 unregister_fuseblk(); 1245 1246 /* 1247 * Make sure all delayed rcu free inodes are flushed before we 1248 * destroy cache. 1249 */ 1250 rcu_barrier(); 1251 kmem_cache_destroy(fuse_inode_cachep); 1252 } 1253 1254 static struct kobject *fuse_kobj; 1255 static struct kobject *connections_kobj; 1256 1257 static int fuse_sysfs_init(void) 1258 { 1259 int err; 1260 1261 fuse_kobj = kobject_create_and_add("fuse", fs_kobj); 1262 if (!fuse_kobj) { 1263 err = -ENOMEM; 1264 goto out_err; 1265 } 1266 1267 connections_kobj = kobject_create_and_add("connections", fuse_kobj); 1268 if (!connections_kobj) { 1269 err = -ENOMEM; 1270 goto out_fuse_unregister; 1271 } 1272 1273 return 0; 1274 1275 out_fuse_unregister: 1276 kobject_put(fuse_kobj); 1277 out_err: 1278 return err; 1279 } 1280 1281 static void fuse_sysfs_cleanup(void) 1282 { 1283 kobject_put(connections_kobj); 1284 kobject_put(fuse_kobj); 1285 } 1286 1287 static int __init fuse_init(void) 1288 { 1289 int res; 1290 1291 printk(KERN_INFO "fuse init (API version %i.%i)\n", 1292 FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION); 1293 1294 INIT_LIST_HEAD(&fuse_conn_list); 1295 res = fuse_fs_init(); 1296 if (res) 1297 goto err; 1298 1299 res = fuse_dev_init(); 1300 if (res) 1301 goto err_fs_cleanup; 1302 1303 res = fuse_sysfs_init(); 1304 if (res) 1305 goto err_dev_cleanup; 1306 1307 res = fuse_ctl_init(); 1308 if (res) 1309 goto err_sysfs_cleanup; 1310 1311 sanitize_global_limit(&max_user_bgreq); 1312 sanitize_global_limit(&max_user_congthresh); 1313 1314 return 0; 1315 1316 err_sysfs_cleanup: 1317 fuse_sysfs_cleanup(); 1318 err_dev_cleanup: 1319 fuse_dev_cleanup(); 1320 err_fs_cleanup: 1321 fuse_fs_cleanup(); 1322 err: 1323 return res; 1324 } 1325 1326 static void __exit fuse_exit(void) 1327 { 1328 printk(KERN_DEBUG "fuse exit\n"); 1329 1330 fuse_ctl_cleanup(); 1331 fuse_sysfs_cleanup(); 1332 fuse_fs_cleanup(); 1333 fuse_dev_cleanup(); 1334 } 1335 1336 module_init(fuse_init); 1337 module_exit(fuse_exit); 1338