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