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 static void fuse_put_super(struct super_block *sb) 380 { 381 struct fuse_conn *fc = get_fuse_conn_super(sb); 382 383 fuse_send_destroy(fc); 384 385 fuse_abort_conn(fc); 386 mutex_lock(&fuse_mutex); 387 list_del(&fc->entry); 388 fuse_ctl_remove_conn(fc); 389 mutex_unlock(&fuse_mutex); 390 fuse_bdi_destroy(fc); 391 392 fuse_conn_put(fc); 393 } 394 395 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr) 396 { 397 stbuf->f_type = FUSE_SUPER_MAGIC; 398 stbuf->f_bsize = attr->bsize; 399 stbuf->f_frsize = attr->frsize; 400 stbuf->f_blocks = attr->blocks; 401 stbuf->f_bfree = attr->bfree; 402 stbuf->f_bavail = attr->bavail; 403 stbuf->f_files = attr->files; 404 stbuf->f_ffree = attr->ffree; 405 stbuf->f_namelen = attr->namelen; 406 /* fsid is left zero */ 407 } 408 409 static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf) 410 { 411 struct super_block *sb = dentry->d_sb; 412 struct fuse_conn *fc = get_fuse_conn_super(sb); 413 FUSE_ARGS(args); 414 struct fuse_statfs_out outarg; 415 int err; 416 417 if (!fuse_allow_current_process(fc)) { 418 buf->f_type = FUSE_SUPER_MAGIC; 419 return 0; 420 } 421 422 memset(&outarg, 0, sizeof(outarg)); 423 args.in.numargs = 0; 424 args.in.h.opcode = FUSE_STATFS; 425 args.in.h.nodeid = get_node_id(dentry->d_inode); 426 args.out.numargs = 1; 427 args.out.args[0].size = 428 fc->minor < 4 ? FUSE_COMPAT_STATFS_SIZE : sizeof(outarg); 429 args.out.args[0].value = &outarg; 430 err = fuse_simple_request(fc, &args); 431 if (!err) 432 convert_fuse_statfs(buf, &outarg.st); 433 return err; 434 } 435 436 enum { 437 OPT_FD, 438 OPT_ROOTMODE, 439 OPT_USER_ID, 440 OPT_GROUP_ID, 441 OPT_DEFAULT_PERMISSIONS, 442 OPT_ALLOW_OTHER, 443 OPT_MAX_READ, 444 OPT_BLKSIZE, 445 OPT_ERR 446 }; 447 448 static const match_table_t tokens = { 449 {OPT_FD, "fd=%u"}, 450 {OPT_ROOTMODE, "rootmode=%o"}, 451 {OPT_USER_ID, "user_id=%u"}, 452 {OPT_GROUP_ID, "group_id=%u"}, 453 {OPT_DEFAULT_PERMISSIONS, "default_permissions"}, 454 {OPT_ALLOW_OTHER, "allow_other"}, 455 {OPT_MAX_READ, "max_read=%u"}, 456 {OPT_BLKSIZE, "blksize=%u"}, 457 {OPT_ERR, NULL} 458 }; 459 460 static int fuse_match_uint(substring_t *s, unsigned int *res) 461 { 462 int err = -ENOMEM; 463 char *buf = match_strdup(s); 464 if (buf) { 465 err = kstrtouint(buf, 10, res); 466 kfree(buf); 467 } 468 return err; 469 } 470 471 static int parse_fuse_opt(char *opt, struct fuse_mount_data *d, int is_bdev) 472 { 473 char *p; 474 memset(d, 0, sizeof(struct fuse_mount_data)); 475 d->max_read = ~0; 476 d->blksize = FUSE_DEFAULT_BLKSIZE; 477 478 while ((p = strsep(&opt, ",")) != NULL) { 479 int token; 480 int value; 481 unsigned uv; 482 substring_t args[MAX_OPT_ARGS]; 483 if (!*p) 484 continue; 485 486 token = match_token(p, tokens, args); 487 switch (token) { 488 case OPT_FD: 489 if (match_int(&args[0], &value)) 490 return 0; 491 d->fd = value; 492 d->fd_present = 1; 493 break; 494 495 case OPT_ROOTMODE: 496 if (match_octal(&args[0], &value)) 497 return 0; 498 if (!fuse_valid_type(value)) 499 return 0; 500 d->rootmode = value; 501 d->rootmode_present = 1; 502 break; 503 504 case OPT_USER_ID: 505 if (fuse_match_uint(&args[0], &uv)) 506 return 0; 507 d->user_id = make_kuid(current_user_ns(), uv); 508 if (!uid_valid(d->user_id)) 509 return 0; 510 d->user_id_present = 1; 511 break; 512 513 case OPT_GROUP_ID: 514 if (fuse_match_uint(&args[0], &uv)) 515 return 0; 516 d->group_id = make_kgid(current_user_ns(), uv); 517 if (!gid_valid(d->group_id)) 518 return 0; 519 d->group_id_present = 1; 520 break; 521 522 case OPT_DEFAULT_PERMISSIONS: 523 d->flags |= FUSE_DEFAULT_PERMISSIONS; 524 break; 525 526 case OPT_ALLOW_OTHER: 527 d->flags |= FUSE_ALLOW_OTHER; 528 break; 529 530 case OPT_MAX_READ: 531 if (match_int(&args[0], &value)) 532 return 0; 533 d->max_read = value; 534 break; 535 536 case OPT_BLKSIZE: 537 if (!is_bdev || match_int(&args[0], &value)) 538 return 0; 539 d->blksize = value; 540 break; 541 542 default: 543 return 0; 544 } 545 } 546 547 if (!d->fd_present || !d->rootmode_present || 548 !d->user_id_present || !d->group_id_present) 549 return 0; 550 551 return 1; 552 } 553 554 static int fuse_show_options(struct seq_file *m, struct dentry *root) 555 { 556 struct super_block *sb = root->d_sb; 557 struct fuse_conn *fc = get_fuse_conn_super(sb); 558 559 seq_printf(m, ",user_id=%u", from_kuid_munged(&init_user_ns, fc->user_id)); 560 seq_printf(m, ",group_id=%u", from_kgid_munged(&init_user_ns, fc->group_id)); 561 if (fc->flags & FUSE_DEFAULT_PERMISSIONS) 562 seq_puts(m, ",default_permissions"); 563 if (fc->flags & FUSE_ALLOW_OTHER) 564 seq_puts(m, ",allow_other"); 565 if (fc->max_read != ~0) 566 seq_printf(m, ",max_read=%u", fc->max_read); 567 if (sb->s_bdev && sb->s_blocksize != FUSE_DEFAULT_BLKSIZE) 568 seq_printf(m, ",blksize=%lu", sb->s_blocksize); 569 return 0; 570 } 571 572 void fuse_conn_init(struct fuse_conn *fc) 573 { 574 memset(fc, 0, sizeof(*fc)); 575 spin_lock_init(&fc->lock); 576 init_rwsem(&fc->killsb); 577 atomic_set(&fc->count, 1); 578 init_waitqueue_head(&fc->waitq); 579 init_waitqueue_head(&fc->blocked_waitq); 580 init_waitqueue_head(&fc->reserved_req_waitq); 581 INIT_LIST_HEAD(&fc->pending); 582 INIT_LIST_HEAD(&fc->processing); 583 INIT_LIST_HEAD(&fc->io); 584 INIT_LIST_HEAD(&fc->interrupts); 585 INIT_LIST_HEAD(&fc->bg_queue); 586 INIT_LIST_HEAD(&fc->entry); 587 fc->forget_list_tail = &fc->forget_list_head; 588 atomic_set(&fc->num_waiting, 0); 589 fc->max_background = FUSE_DEFAULT_MAX_BACKGROUND; 590 fc->congestion_threshold = FUSE_DEFAULT_CONGESTION_THRESHOLD; 591 fc->khctr = 0; 592 fc->polled_files = RB_ROOT; 593 fc->reqctr = 0; 594 fc->blocked = 0; 595 fc->initialized = 0; 596 fc->attr_version = 1; 597 get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key)); 598 } 599 EXPORT_SYMBOL_GPL(fuse_conn_init); 600 601 void fuse_conn_put(struct fuse_conn *fc) 602 { 603 if (atomic_dec_and_test(&fc->count)) { 604 if (fc->destroy_req) 605 fuse_request_free(fc->destroy_req); 606 fc->release(fc); 607 } 608 } 609 EXPORT_SYMBOL_GPL(fuse_conn_put); 610 611 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc) 612 { 613 atomic_inc(&fc->count); 614 return fc; 615 } 616 EXPORT_SYMBOL_GPL(fuse_conn_get); 617 618 static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned mode) 619 { 620 struct fuse_attr attr; 621 memset(&attr, 0, sizeof(attr)); 622 623 attr.mode = mode; 624 attr.ino = FUSE_ROOT_ID; 625 attr.nlink = 1; 626 return fuse_iget(sb, 1, 0, &attr, 0, 0); 627 } 628 629 struct fuse_inode_handle { 630 u64 nodeid; 631 u32 generation; 632 }; 633 634 static struct dentry *fuse_get_dentry(struct super_block *sb, 635 struct fuse_inode_handle *handle) 636 { 637 struct fuse_conn *fc = get_fuse_conn_super(sb); 638 struct inode *inode; 639 struct dentry *entry; 640 int err = -ESTALE; 641 642 if (handle->nodeid == 0) 643 goto out_err; 644 645 inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid); 646 if (!inode) { 647 struct fuse_entry_out outarg; 648 struct qstr name; 649 650 if (!fc->export_support) 651 goto out_err; 652 653 name.len = 1; 654 name.name = "."; 655 err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg, 656 &inode); 657 if (err && err != -ENOENT) 658 goto out_err; 659 if (err || !inode) { 660 err = -ESTALE; 661 goto out_err; 662 } 663 err = -EIO; 664 if (get_node_id(inode) != handle->nodeid) 665 goto out_iput; 666 } 667 err = -ESTALE; 668 if (inode->i_generation != handle->generation) 669 goto out_iput; 670 671 entry = d_obtain_alias(inode); 672 if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID) 673 fuse_invalidate_entry_cache(entry); 674 675 return entry; 676 677 out_iput: 678 iput(inode); 679 out_err: 680 return ERR_PTR(err); 681 } 682 683 static int fuse_encode_fh(struct inode *inode, u32 *fh, int *max_len, 684 struct inode *parent) 685 { 686 int len = parent ? 6 : 3; 687 u64 nodeid; 688 u32 generation; 689 690 if (*max_len < len) { 691 *max_len = len; 692 return FILEID_INVALID; 693 } 694 695 nodeid = get_fuse_inode(inode)->nodeid; 696 generation = inode->i_generation; 697 698 fh[0] = (u32)(nodeid >> 32); 699 fh[1] = (u32)(nodeid & 0xffffffff); 700 fh[2] = generation; 701 702 if (parent) { 703 nodeid = get_fuse_inode(parent)->nodeid; 704 generation = parent->i_generation; 705 706 fh[3] = (u32)(nodeid >> 32); 707 fh[4] = (u32)(nodeid & 0xffffffff); 708 fh[5] = generation; 709 } 710 711 *max_len = len; 712 return parent ? 0x82 : 0x81; 713 } 714 715 static struct dentry *fuse_fh_to_dentry(struct super_block *sb, 716 struct fid *fid, int fh_len, int fh_type) 717 { 718 struct fuse_inode_handle handle; 719 720 if ((fh_type != 0x81 && fh_type != 0x82) || fh_len < 3) 721 return NULL; 722 723 handle.nodeid = (u64) fid->raw[0] << 32; 724 handle.nodeid |= (u64) fid->raw[1]; 725 handle.generation = fid->raw[2]; 726 return fuse_get_dentry(sb, &handle); 727 } 728 729 static struct dentry *fuse_fh_to_parent(struct super_block *sb, 730 struct fid *fid, int fh_len, int fh_type) 731 { 732 struct fuse_inode_handle parent; 733 734 if (fh_type != 0x82 || fh_len < 6) 735 return NULL; 736 737 parent.nodeid = (u64) fid->raw[3] << 32; 738 parent.nodeid |= (u64) fid->raw[4]; 739 parent.generation = fid->raw[5]; 740 return fuse_get_dentry(sb, &parent); 741 } 742 743 static struct dentry *fuse_get_parent(struct dentry *child) 744 { 745 struct inode *child_inode = child->d_inode; 746 struct fuse_conn *fc = get_fuse_conn(child_inode); 747 struct inode *inode; 748 struct dentry *parent; 749 struct fuse_entry_out outarg; 750 struct qstr name; 751 int err; 752 753 if (!fc->export_support) 754 return ERR_PTR(-ESTALE); 755 756 name.len = 2; 757 name.name = ".."; 758 err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode), 759 &name, &outarg, &inode); 760 if (err) { 761 if (err == -ENOENT) 762 return ERR_PTR(-ESTALE); 763 return ERR_PTR(err); 764 } 765 766 parent = d_obtain_alias(inode); 767 if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID) 768 fuse_invalidate_entry_cache(parent); 769 770 return parent; 771 } 772 773 static const struct export_operations fuse_export_operations = { 774 .fh_to_dentry = fuse_fh_to_dentry, 775 .fh_to_parent = fuse_fh_to_parent, 776 .encode_fh = fuse_encode_fh, 777 .get_parent = fuse_get_parent, 778 }; 779 780 static const struct super_operations fuse_super_operations = { 781 .alloc_inode = fuse_alloc_inode, 782 .destroy_inode = fuse_destroy_inode, 783 .evict_inode = fuse_evict_inode, 784 .write_inode = fuse_write_inode, 785 .drop_inode = generic_delete_inode, 786 .remount_fs = fuse_remount_fs, 787 .put_super = fuse_put_super, 788 .umount_begin = fuse_umount_begin, 789 .statfs = fuse_statfs, 790 .show_options = fuse_show_options, 791 }; 792 793 static void sanitize_global_limit(unsigned *limit) 794 { 795 if (*limit == 0) 796 *limit = ((totalram_pages << PAGE_SHIFT) >> 13) / 797 sizeof(struct fuse_req); 798 799 if (*limit >= 1 << 16) 800 *limit = (1 << 16) - 1; 801 } 802 803 static int set_global_limit(const char *val, struct kernel_param *kp) 804 { 805 int rv; 806 807 rv = param_set_uint(val, kp); 808 if (rv) 809 return rv; 810 811 sanitize_global_limit((unsigned *)kp->arg); 812 813 return 0; 814 } 815 816 static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg) 817 { 818 int cap_sys_admin = capable(CAP_SYS_ADMIN); 819 820 if (arg->minor < 13) 821 return; 822 823 sanitize_global_limit(&max_user_bgreq); 824 sanitize_global_limit(&max_user_congthresh); 825 826 if (arg->max_background) { 827 fc->max_background = arg->max_background; 828 829 if (!cap_sys_admin && fc->max_background > max_user_bgreq) 830 fc->max_background = max_user_bgreq; 831 } 832 if (arg->congestion_threshold) { 833 fc->congestion_threshold = arg->congestion_threshold; 834 835 if (!cap_sys_admin && 836 fc->congestion_threshold > max_user_congthresh) 837 fc->congestion_threshold = max_user_congthresh; 838 } 839 } 840 841 static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req) 842 { 843 struct fuse_init_out *arg = &req->misc.init_out; 844 845 if (req->out.h.error || arg->major != FUSE_KERNEL_VERSION) 846 fc->conn_error = 1; 847 else { 848 unsigned long ra_pages; 849 850 process_init_limits(fc, arg); 851 852 if (arg->minor >= 6) { 853 ra_pages = arg->max_readahead / PAGE_CACHE_SIZE; 854 if (arg->flags & FUSE_ASYNC_READ) 855 fc->async_read = 1; 856 if (!(arg->flags & FUSE_POSIX_LOCKS)) 857 fc->no_lock = 1; 858 if (arg->minor >= 17) { 859 if (!(arg->flags & FUSE_FLOCK_LOCKS)) 860 fc->no_flock = 1; 861 } else { 862 if (!(arg->flags & FUSE_POSIX_LOCKS)) 863 fc->no_flock = 1; 864 } 865 if (arg->flags & FUSE_ATOMIC_O_TRUNC) 866 fc->atomic_o_trunc = 1; 867 if (arg->minor >= 9) { 868 /* LOOKUP has dependency on proto version */ 869 if (arg->flags & FUSE_EXPORT_SUPPORT) 870 fc->export_support = 1; 871 } 872 if (arg->flags & FUSE_BIG_WRITES) 873 fc->big_writes = 1; 874 if (arg->flags & FUSE_DONT_MASK) 875 fc->dont_mask = 1; 876 if (arg->flags & FUSE_AUTO_INVAL_DATA) 877 fc->auto_inval_data = 1; 878 if (arg->flags & FUSE_DO_READDIRPLUS) { 879 fc->do_readdirplus = 1; 880 if (arg->flags & FUSE_READDIRPLUS_AUTO) 881 fc->readdirplus_auto = 1; 882 } 883 if (arg->flags & FUSE_ASYNC_DIO) 884 fc->async_dio = 1; 885 if (arg->flags & FUSE_WRITEBACK_CACHE) 886 fc->writeback_cache = 1; 887 if (arg->time_gran && arg->time_gran <= 1000000000) 888 fc->sb->s_time_gran = arg->time_gran; 889 } else { 890 ra_pages = fc->max_read / PAGE_CACHE_SIZE; 891 fc->no_lock = 1; 892 fc->no_flock = 1; 893 } 894 895 fc->bdi.ra_pages = min(fc->bdi.ra_pages, ra_pages); 896 fc->minor = arg->minor; 897 fc->max_write = arg->minor < 5 ? 4096 : arg->max_write; 898 fc->max_write = max_t(unsigned, 4096, fc->max_write); 899 fc->conn_init = 1; 900 } 901 fc->initialized = 1; 902 wake_up_all(&fc->blocked_waitq); 903 } 904 905 static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req) 906 { 907 struct fuse_init_in *arg = &req->misc.init_in; 908 909 arg->major = FUSE_KERNEL_VERSION; 910 arg->minor = FUSE_KERNEL_MINOR_VERSION; 911 arg->max_readahead = fc->bdi.ra_pages * PAGE_CACHE_SIZE; 912 arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC | 913 FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK | 914 FUSE_SPLICE_WRITE | FUSE_SPLICE_MOVE | FUSE_SPLICE_READ | 915 FUSE_FLOCK_LOCKS | FUSE_IOCTL_DIR | FUSE_AUTO_INVAL_DATA | 916 FUSE_DO_READDIRPLUS | FUSE_READDIRPLUS_AUTO | FUSE_ASYNC_DIO | 917 FUSE_WRITEBACK_CACHE | FUSE_NO_OPEN_SUPPORT; 918 req->in.h.opcode = FUSE_INIT; 919 req->in.numargs = 1; 920 req->in.args[0].size = sizeof(*arg); 921 req->in.args[0].value = arg; 922 req->out.numargs = 1; 923 /* Variable length argument used for backward compatibility 924 with interface version < 7.5. Rest of init_out is zeroed 925 by do_get_request(), so a short reply is not a problem */ 926 req->out.argvar = 1; 927 req->out.args[0].size = sizeof(struct fuse_init_out); 928 req->out.args[0].value = &req->misc.init_out; 929 req->end = process_init_reply; 930 fuse_request_send_background(fc, req); 931 } 932 933 static void fuse_free_conn(struct fuse_conn *fc) 934 { 935 kfree_rcu(fc, rcu); 936 } 937 938 static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb) 939 { 940 int err; 941 942 fc->bdi.name = "fuse"; 943 fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE; 944 /* fuse does it's own writeback accounting */ 945 fc->bdi.capabilities = BDI_CAP_NO_ACCT_WB | BDI_CAP_STRICTLIMIT; 946 947 err = bdi_init(&fc->bdi); 948 if (err) 949 return err; 950 951 fc->bdi_initialized = 1; 952 953 if (sb->s_bdev) { 954 err = bdi_register(&fc->bdi, NULL, "%u:%u-fuseblk", 955 MAJOR(fc->dev), MINOR(fc->dev)); 956 } else { 957 err = bdi_register_dev(&fc->bdi, fc->dev); 958 } 959 960 if (err) 961 return err; 962 963 /* 964 * For a single fuse filesystem use max 1% of dirty + 965 * writeback threshold. 966 * 967 * This gives about 1M of write buffer for memory maps on a 968 * machine with 1G and 10% dirty_ratio, which should be more 969 * than enough. 970 * 971 * Privileged users can raise it by writing to 972 * 973 * /sys/class/bdi/<bdi>/max_ratio 974 */ 975 bdi_set_max_ratio(&fc->bdi, 1); 976 977 return 0; 978 } 979 980 static int fuse_fill_super(struct super_block *sb, void *data, int silent) 981 { 982 struct fuse_conn *fc; 983 struct inode *root; 984 struct fuse_mount_data d; 985 struct file *file; 986 struct dentry *root_dentry; 987 struct fuse_req *init_req; 988 int err; 989 int is_bdev = sb->s_bdev != NULL; 990 991 err = -EINVAL; 992 if (sb->s_flags & MS_MANDLOCK) 993 goto err; 994 995 sb->s_flags &= ~(MS_NOSEC | MS_I_VERSION); 996 997 if (!parse_fuse_opt(data, &d, is_bdev)) 998 goto err; 999 1000 if (is_bdev) { 1001 #ifdef CONFIG_BLOCK 1002 err = -EINVAL; 1003 if (!sb_set_blocksize(sb, d.blksize)) 1004 goto err; 1005 #endif 1006 } else { 1007 sb->s_blocksize = PAGE_CACHE_SIZE; 1008 sb->s_blocksize_bits = PAGE_CACHE_SHIFT; 1009 } 1010 sb->s_magic = FUSE_SUPER_MAGIC; 1011 sb->s_op = &fuse_super_operations; 1012 sb->s_maxbytes = MAX_LFS_FILESIZE; 1013 sb->s_time_gran = 1; 1014 sb->s_export_op = &fuse_export_operations; 1015 1016 file = fget(d.fd); 1017 err = -EINVAL; 1018 if (!file) 1019 goto err; 1020 1021 if ((file->f_op != &fuse_dev_operations) || 1022 (file->f_cred->user_ns != &init_user_ns)) 1023 goto err_fput; 1024 1025 fc = kmalloc(sizeof(*fc), GFP_KERNEL); 1026 err = -ENOMEM; 1027 if (!fc) 1028 goto err_fput; 1029 1030 fuse_conn_init(fc); 1031 1032 fc->dev = sb->s_dev; 1033 fc->sb = sb; 1034 err = fuse_bdi_init(fc, sb); 1035 if (err) 1036 goto err_put_conn; 1037 1038 sb->s_bdi = &fc->bdi; 1039 1040 /* Handle umasking inside the fuse code */ 1041 if (sb->s_flags & MS_POSIXACL) 1042 fc->dont_mask = 1; 1043 sb->s_flags |= MS_POSIXACL; 1044 1045 fc->release = fuse_free_conn; 1046 fc->flags = d.flags; 1047 fc->user_id = d.user_id; 1048 fc->group_id = d.group_id; 1049 fc->max_read = max_t(unsigned, 4096, d.max_read); 1050 1051 /* Used by get_root_inode() */ 1052 sb->s_fs_info = fc; 1053 1054 err = -ENOMEM; 1055 root = fuse_get_root_inode(sb, d.rootmode); 1056 root_dentry = d_make_root(root); 1057 if (!root_dentry) 1058 goto err_put_conn; 1059 /* only now - we want root dentry with NULL ->d_op */ 1060 sb->s_d_op = &fuse_dentry_operations; 1061 1062 init_req = fuse_request_alloc(0); 1063 if (!init_req) 1064 goto err_put_root; 1065 init_req->background = 1; 1066 1067 if (is_bdev) { 1068 fc->destroy_req = fuse_request_alloc(0); 1069 if (!fc->destroy_req) 1070 goto err_free_init_req; 1071 } 1072 1073 mutex_lock(&fuse_mutex); 1074 err = -EINVAL; 1075 if (file->private_data) 1076 goto err_unlock; 1077 1078 err = fuse_ctl_add_conn(fc); 1079 if (err) 1080 goto err_unlock; 1081 1082 list_add_tail(&fc->entry, &fuse_conn_list); 1083 sb->s_root = root_dentry; 1084 fc->connected = 1; 1085 file->private_data = fuse_conn_get(fc); 1086 mutex_unlock(&fuse_mutex); 1087 /* 1088 * atomic_dec_and_test() in fput() provides the necessary 1089 * memory barrier for file->private_data to be visible on all 1090 * CPUs after this 1091 */ 1092 fput(file); 1093 1094 fuse_send_init(fc, init_req); 1095 1096 return 0; 1097 1098 err_unlock: 1099 mutex_unlock(&fuse_mutex); 1100 err_free_init_req: 1101 fuse_request_free(init_req); 1102 err_put_root: 1103 dput(root_dentry); 1104 err_put_conn: 1105 fuse_bdi_destroy(fc); 1106 fuse_conn_put(fc); 1107 err_fput: 1108 fput(file); 1109 err: 1110 return err; 1111 } 1112 1113 static struct dentry *fuse_mount(struct file_system_type *fs_type, 1114 int flags, const char *dev_name, 1115 void *raw_data) 1116 { 1117 return mount_nodev(fs_type, flags, raw_data, fuse_fill_super); 1118 } 1119 1120 static void fuse_kill_sb_anon(struct super_block *sb) 1121 { 1122 struct fuse_conn *fc = get_fuse_conn_super(sb); 1123 1124 if (fc) { 1125 down_write(&fc->killsb); 1126 fc->sb = NULL; 1127 up_write(&fc->killsb); 1128 } 1129 1130 kill_anon_super(sb); 1131 } 1132 1133 static struct file_system_type fuse_fs_type = { 1134 .owner = THIS_MODULE, 1135 .name = "fuse", 1136 .fs_flags = FS_HAS_SUBTYPE, 1137 .mount = fuse_mount, 1138 .kill_sb = fuse_kill_sb_anon, 1139 }; 1140 MODULE_ALIAS_FS("fuse"); 1141 1142 #ifdef CONFIG_BLOCK 1143 static struct dentry *fuse_mount_blk(struct file_system_type *fs_type, 1144 int flags, const char *dev_name, 1145 void *raw_data) 1146 { 1147 return mount_bdev(fs_type, flags, dev_name, raw_data, fuse_fill_super); 1148 } 1149 1150 static void fuse_kill_sb_blk(struct super_block *sb) 1151 { 1152 struct fuse_conn *fc = get_fuse_conn_super(sb); 1153 1154 if (fc) { 1155 down_write(&fc->killsb); 1156 fc->sb = NULL; 1157 up_write(&fc->killsb); 1158 } 1159 1160 kill_block_super(sb); 1161 } 1162 1163 static struct file_system_type fuseblk_fs_type = { 1164 .owner = THIS_MODULE, 1165 .name = "fuseblk", 1166 .mount = fuse_mount_blk, 1167 .kill_sb = fuse_kill_sb_blk, 1168 .fs_flags = FS_REQUIRES_DEV | FS_HAS_SUBTYPE, 1169 }; 1170 MODULE_ALIAS_FS("fuseblk"); 1171 1172 static inline int register_fuseblk(void) 1173 { 1174 return register_filesystem(&fuseblk_fs_type); 1175 } 1176 1177 static inline void unregister_fuseblk(void) 1178 { 1179 unregister_filesystem(&fuseblk_fs_type); 1180 } 1181 #else 1182 static inline int register_fuseblk(void) 1183 { 1184 return 0; 1185 } 1186 1187 static inline void unregister_fuseblk(void) 1188 { 1189 } 1190 #endif 1191 1192 static void fuse_inode_init_once(void *foo) 1193 { 1194 struct inode *inode = foo; 1195 1196 inode_init_once(inode); 1197 } 1198 1199 static int __init fuse_fs_init(void) 1200 { 1201 int err; 1202 1203 fuse_inode_cachep = kmem_cache_create("fuse_inode", 1204 sizeof(struct fuse_inode), 1205 0, SLAB_HWCACHE_ALIGN, 1206 fuse_inode_init_once); 1207 err = -ENOMEM; 1208 if (!fuse_inode_cachep) 1209 goto out; 1210 1211 err = register_fuseblk(); 1212 if (err) 1213 goto out2; 1214 1215 err = register_filesystem(&fuse_fs_type); 1216 if (err) 1217 goto out3; 1218 1219 return 0; 1220 1221 out3: 1222 unregister_fuseblk(); 1223 out2: 1224 kmem_cache_destroy(fuse_inode_cachep); 1225 out: 1226 return err; 1227 } 1228 1229 static void fuse_fs_cleanup(void) 1230 { 1231 unregister_filesystem(&fuse_fs_type); 1232 unregister_fuseblk(); 1233 1234 /* 1235 * Make sure all delayed rcu free inodes are flushed before we 1236 * destroy cache. 1237 */ 1238 rcu_barrier(); 1239 kmem_cache_destroy(fuse_inode_cachep); 1240 } 1241 1242 static struct kobject *fuse_kobj; 1243 static struct kobject *connections_kobj; 1244 1245 static int fuse_sysfs_init(void) 1246 { 1247 int err; 1248 1249 fuse_kobj = kobject_create_and_add("fuse", fs_kobj); 1250 if (!fuse_kobj) { 1251 err = -ENOMEM; 1252 goto out_err; 1253 } 1254 1255 connections_kobj = kobject_create_and_add("connections", fuse_kobj); 1256 if (!connections_kobj) { 1257 err = -ENOMEM; 1258 goto out_fuse_unregister; 1259 } 1260 1261 return 0; 1262 1263 out_fuse_unregister: 1264 kobject_put(fuse_kobj); 1265 out_err: 1266 return err; 1267 } 1268 1269 static void fuse_sysfs_cleanup(void) 1270 { 1271 kobject_put(connections_kobj); 1272 kobject_put(fuse_kobj); 1273 } 1274 1275 static int __init fuse_init(void) 1276 { 1277 int res; 1278 1279 printk(KERN_INFO "fuse init (API version %i.%i)\n", 1280 FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION); 1281 1282 INIT_LIST_HEAD(&fuse_conn_list); 1283 res = fuse_fs_init(); 1284 if (res) 1285 goto err; 1286 1287 res = fuse_dev_init(); 1288 if (res) 1289 goto err_fs_cleanup; 1290 1291 res = fuse_sysfs_init(); 1292 if (res) 1293 goto err_dev_cleanup; 1294 1295 res = fuse_ctl_init(); 1296 if (res) 1297 goto err_sysfs_cleanup; 1298 1299 sanitize_global_limit(&max_user_bgreq); 1300 sanitize_global_limit(&max_user_congthresh); 1301 1302 return 0; 1303 1304 err_sysfs_cleanup: 1305 fuse_sysfs_cleanup(); 1306 err_dev_cleanup: 1307 fuse_dev_cleanup(); 1308 err_fs_cleanup: 1309 fuse_fs_cleanup(); 1310 err: 1311 return res; 1312 } 1313 1314 static void __exit fuse_exit(void) 1315 { 1316 printk(KERN_DEBUG "fuse exit\n"); 1317 1318 fuse_ctl_cleanup(); 1319 fuse_sysfs_cleanup(); 1320 fuse_fs_cleanup(); 1321 fuse_dev_cleanup(); 1322 } 1323 1324 module_init(fuse_init); 1325 module_exit(fuse_exit); 1326