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 fuse_init_inode(inode, attr); 312 unlock_new_inode(inode); 313 } else if ((inode->i_mode ^ attr->mode) & S_IFMT) { 314 /* Inode has changed type, any I/O on the old should fail */ 315 make_bad_inode(inode); 316 iput(inode); 317 goto retry; 318 } 319 320 fi = get_fuse_inode(inode); 321 spin_lock(&fc->lock); 322 fi->nlookup++; 323 spin_unlock(&fc->lock); 324 fuse_change_attributes(inode, attr, attr_valid, attr_version); 325 326 return inode; 327 } 328 329 int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid, 330 loff_t offset, loff_t len) 331 { 332 struct inode *inode; 333 pgoff_t pg_start; 334 pgoff_t pg_end; 335 336 inode = ilookup5(sb, nodeid, fuse_inode_eq, &nodeid); 337 if (!inode) 338 return -ENOENT; 339 340 fuse_invalidate_attr(inode); 341 if (offset >= 0) { 342 pg_start = offset >> PAGE_CACHE_SHIFT; 343 if (len <= 0) 344 pg_end = -1; 345 else 346 pg_end = (offset + len - 1) >> PAGE_CACHE_SHIFT; 347 invalidate_inode_pages2_range(inode->i_mapping, 348 pg_start, pg_end); 349 } 350 iput(inode); 351 return 0; 352 } 353 354 static void fuse_umount_begin(struct super_block *sb) 355 { 356 fuse_abort_conn(get_fuse_conn_super(sb)); 357 } 358 359 static void fuse_send_destroy(struct fuse_conn *fc) 360 { 361 struct fuse_req *req = fc->destroy_req; 362 if (req && fc->conn_init) { 363 fc->destroy_req = NULL; 364 req->in.h.opcode = FUSE_DESTROY; 365 req->force = 1; 366 req->background = 0; 367 fuse_request_send(fc, req); 368 fuse_put_request(fc, req); 369 } 370 } 371 372 static void fuse_bdi_destroy(struct fuse_conn *fc) 373 { 374 if (fc->bdi_initialized) 375 bdi_destroy(&fc->bdi); 376 } 377 378 static void fuse_put_super(struct super_block *sb) 379 { 380 struct fuse_conn *fc = get_fuse_conn_super(sb); 381 382 fuse_send_destroy(fc); 383 384 fuse_abort_conn(fc); 385 mutex_lock(&fuse_mutex); 386 list_del(&fc->entry); 387 fuse_ctl_remove_conn(fc); 388 mutex_unlock(&fuse_mutex); 389 fuse_bdi_destroy(fc); 390 391 fuse_conn_put(fc); 392 } 393 394 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr) 395 { 396 stbuf->f_type = FUSE_SUPER_MAGIC; 397 stbuf->f_bsize = attr->bsize; 398 stbuf->f_frsize = attr->frsize; 399 stbuf->f_blocks = attr->blocks; 400 stbuf->f_bfree = attr->bfree; 401 stbuf->f_bavail = attr->bavail; 402 stbuf->f_files = attr->files; 403 stbuf->f_ffree = attr->ffree; 404 stbuf->f_namelen = attr->namelen; 405 /* fsid is left zero */ 406 } 407 408 static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf) 409 { 410 struct super_block *sb = dentry->d_sb; 411 struct fuse_conn *fc = get_fuse_conn_super(sb); 412 FUSE_ARGS(args); 413 struct fuse_statfs_out outarg; 414 int err; 415 416 if (!fuse_allow_current_process(fc)) { 417 buf->f_type = FUSE_SUPER_MAGIC; 418 return 0; 419 } 420 421 memset(&outarg, 0, sizeof(outarg)); 422 args.in.numargs = 0; 423 args.in.h.opcode = FUSE_STATFS; 424 args.in.h.nodeid = get_node_id(d_inode(dentry)); 425 args.out.numargs = 1; 426 args.out.args[0].size = sizeof(outarg); 427 args.out.args[0].value = &outarg; 428 err = fuse_simple_request(fc, &args); 429 if (!err) 430 convert_fuse_statfs(buf, &outarg.st); 431 return err; 432 } 433 434 enum { 435 OPT_FD, 436 OPT_ROOTMODE, 437 OPT_USER_ID, 438 OPT_GROUP_ID, 439 OPT_DEFAULT_PERMISSIONS, 440 OPT_ALLOW_OTHER, 441 OPT_MAX_READ, 442 OPT_BLKSIZE, 443 OPT_ERR 444 }; 445 446 static const match_table_t tokens = { 447 {OPT_FD, "fd=%u"}, 448 {OPT_ROOTMODE, "rootmode=%o"}, 449 {OPT_USER_ID, "user_id=%u"}, 450 {OPT_GROUP_ID, "group_id=%u"}, 451 {OPT_DEFAULT_PERMISSIONS, "default_permissions"}, 452 {OPT_ALLOW_OTHER, "allow_other"}, 453 {OPT_MAX_READ, "max_read=%u"}, 454 {OPT_BLKSIZE, "blksize=%u"}, 455 {OPT_ERR, NULL} 456 }; 457 458 static int fuse_match_uint(substring_t *s, unsigned int *res) 459 { 460 int err = -ENOMEM; 461 char *buf = match_strdup(s); 462 if (buf) { 463 err = kstrtouint(buf, 10, res); 464 kfree(buf); 465 } 466 return err; 467 } 468 469 static int parse_fuse_opt(char *opt, struct fuse_mount_data *d, int is_bdev) 470 { 471 char *p; 472 memset(d, 0, sizeof(struct fuse_mount_data)); 473 d->max_read = ~0; 474 d->blksize = FUSE_DEFAULT_BLKSIZE; 475 476 while ((p = strsep(&opt, ",")) != NULL) { 477 int token; 478 int value; 479 unsigned uv; 480 substring_t args[MAX_OPT_ARGS]; 481 if (!*p) 482 continue; 483 484 token = match_token(p, tokens, args); 485 switch (token) { 486 case OPT_FD: 487 if (match_int(&args[0], &value)) 488 return 0; 489 d->fd = value; 490 d->fd_present = 1; 491 break; 492 493 case OPT_ROOTMODE: 494 if (match_octal(&args[0], &value)) 495 return 0; 496 if (!fuse_valid_type(value)) 497 return 0; 498 d->rootmode = value; 499 d->rootmode_present = 1; 500 break; 501 502 case OPT_USER_ID: 503 if (fuse_match_uint(&args[0], &uv)) 504 return 0; 505 d->user_id = make_kuid(current_user_ns(), uv); 506 if (!uid_valid(d->user_id)) 507 return 0; 508 d->user_id_present = 1; 509 break; 510 511 case OPT_GROUP_ID: 512 if (fuse_match_uint(&args[0], &uv)) 513 return 0; 514 d->group_id = make_kgid(current_user_ns(), uv); 515 if (!gid_valid(d->group_id)) 516 return 0; 517 d->group_id_present = 1; 518 break; 519 520 case OPT_DEFAULT_PERMISSIONS: 521 d->flags |= FUSE_DEFAULT_PERMISSIONS; 522 break; 523 524 case OPT_ALLOW_OTHER: 525 d->flags |= FUSE_ALLOW_OTHER; 526 break; 527 528 case OPT_MAX_READ: 529 if (match_int(&args[0], &value)) 530 return 0; 531 d->max_read = value; 532 break; 533 534 case OPT_BLKSIZE: 535 if (!is_bdev || match_int(&args[0], &value)) 536 return 0; 537 d->blksize = value; 538 break; 539 540 default: 541 return 0; 542 } 543 } 544 545 if (!d->fd_present || !d->rootmode_present || 546 !d->user_id_present || !d->group_id_present) 547 return 0; 548 549 return 1; 550 } 551 552 static int fuse_show_options(struct seq_file *m, struct dentry *root) 553 { 554 struct super_block *sb = root->d_sb; 555 struct fuse_conn *fc = get_fuse_conn_super(sb); 556 557 seq_printf(m, ",user_id=%u", from_kuid_munged(&init_user_ns, fc->user_id)); 558 seq_printf(m, ",group_id=%u", from_kgid_munged(&init_user_ns, fc->group_id)); 559 if (fc->flags & FUSE_DEFAULT_PERMISSIONS) 560 seq_puts(m, ",default_permissions"); 561 if (fc->flags & FUSE_ALLOW_OTHER) 562 seq_puts(m, ",allow_other"); 563 if (fc->max_read != ~0) 564 seq_printf(m, ",max_read=%u", fc->max_read); 565 if (sb->s_bdev && sb->s_blocksize != FUSE_DEFAULT_BLKSIZE) 566 seq_printf(m, ",blksize=%lu", sb->s_blocksize); 567 return 0; 568 } 569 570 void fuse_conn_init(struct fuse_conn *fc) 571 { 572 memset(fc, 0, sizeof(*fc)); 573 spin_lock_init(&fc->lock); 574 init_rwsem(&fc->killsb); 575 atomic_set(&fc->count, 1); 576 init_waitqueue_head(&fc->waitq); 577 init_waitqueue_head(&fc->blocked_waitq); 578 init_waitqueue_head(&fc->reserved_req_waitq); 579 INIT_LIST_HEAD(&fc->pending); 580 INIT_LIST_HEAD(&fc->processing); 581 INIT_LIST_HEAD(&fc->io); 582 INIT_LIST_HEAD(&fc->interrupts); 583 INIT_LIST_HEAD(&fc->bg_queue); 584 INIT_LIST_HEAD(&fc->entry); 585 fc->forget_list_tail = &fc->forget_list_head; 586 atomic_set(&fc->num_waiting, 0); 587 fc->max_background = FUSE_DEFAULT_MAX_BACKGROUND; 588 fc->congestion_threshold = FUSE_DEFAULT_CONGESTION_THRESHOLD; 589 fc->khctr = 0; 590 fc->polled_files = RB_ROOT; 591 fc->reqctr = 0; 592 fc->blocked = 0; 593 fc->initialized = 0; 594 fc->attr_version = 1; 595 get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key)); 596 } 597 EXPORT_SYMBOL_GPL(fuse_conn_init); 598 599 void fuse_conn_put(struct fuse_conn *fc) 600 { 601 if (atomic_dec_and_test(&fc->count)) { 602 if (fc->destroy_req) 603 fuse_request_free(fc->destroy_req); 604 fc->release(fc); 605 } 606 } 607 EXPORT_SYMBOL_GPL(fuse_conn_put); 608 609 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc) 610 { 611 atomic_inc(&fc->count); 612 return fc; 613 } 614 EXPORT_SYMBOL_GPL(fuse_conn_get); 615 616 static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned mode) 617 { 618 struct fuse_attr attr; 619 memset(&attr, 0, sizeof(attr)); 620 621 attr.mode = mode; 622 attr.ino = FUSE_ROOT_ID; 623 attr.nlink = 1; 624 return fuse_iget(sb, 1, 0, &attr, 0, 0); 625 } 626 627 struct fuse_inode_handle { 628 u64 nodeid; 629 u32 generation; 630 }; 631 632 static struct dentry *fuse_get_dentry(struct super_block *sb, 633 struct fuse_inode_handle *handle) 634 { 635 struct fuse_conn *fc = get_fuse_conn_super(sb); 636 struct inode *inode; 637 struct dentry *entry; 638 int err = -ESTALE; 639 640 if (handle->nodeid == 0) 641 goto out_err; 642 643 inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid); 644 if (!inode) { 645 struct fuse_entry_out outarg; 646 struct qstr name; 647 648 if (!fc->export_support) 649 goto out_err; 650 651 name.len = 1; 652 name.name = "."; 653 err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg, 654 &inode); 655 if (err && err != -ENOENT) 656 goto out_err; 657 if (err || !inode) { 658 err = -ESTALE; 659 goto out_err; 660 } 661 err = -EIO; 662 if (get_node_id(inode) != handle->nodeid) 663 goto out_iput; 664 } 665 err = -ESTALE; 666 if (inode->i_generation != handle->generation) 667 goto out_iput; 668 669 entry = d_obtain_alias(inode); 670 if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID) 671 fuse_invalidate_entry_cache(entry); 672 673 return entry; 674 675 out_iput: 676 iput(inode); 677 out_err: 678 return ERR_PTR(err); 679 } 680 681 static int fuse_encode_fh(struct inode *inode, u32 *fh, int *max_len, 682 struct inode *parent) 683 { 684 int len = parent ? 6 : 3; 685 u64 nodeid; 686 u32 generation; 687 688 if (*max_len < len) { 689 *max_len = len; 690 return FILEID_INVALID; 691 } 692 693 nodeid = get_fuse_inode(inode)->nodeid; 694 generation = inode->i_generation; 695 696 fh[0] = (u32)(nodeid >> 32); 697 fh[1] = (u32)(nodeid & 0xffffffff); 698 fh[2] = generation; 699 700 if (parent) { 701 nodeid = get_fuse_inode(parent)->nodeid; 702 generation = parent->i_generation; 703 704 fh[3] = (u32)(nodeid >> 32); 705 fh[4] = (u32)(nodeid & 0xffffffff); 706 fh[5] = generation; 707 } 708 709 *max_len = len; 710 return parent ? 0x82 : 0x81; 711 } 712 713 static struct dentry *fuse_fh_to_dentry(struct super_block *sb, 714 struct fid *fid, int fh_len, int fh_type) 715 { 716 struct fuse_inode_handle handle; 717 718 if ((fh_type != 0x81 && fh_type != 0x82) || fh_len < 3) 719 return NULL; 720 721 handle.nodeid = (u64) fid->raw[0] << 32; 722 handle.nodeid |= (u64) fid->raw[1]; 723 handle.generation = fid->raw[2]; 724 return fuse_get_dentry(sb, &handle); 725 } 726 727 static struct dentry *fuse_fh_to_parent(struct super_block *sb, 728 struct fid *fid, int fh_len, int fh_type) 729 { 730 struct fuse_inode_handle parent; 731 732 if (fh_type != 0x82 || fh_len < 6) 733 return NULL; 734 735 parent.nodeid = (u64) fid->raw[3] << 32; 736 parent.nodeid |= (u64) fid->raw[4]; 737 parent.generation = fid->raw[5]; 738 return fuse_get_dentry(sb, &parent); 739 } 740 741 static struct dentry *fuse_get_parent(struct dentry *child) 742 { 743 struct inode *child_inode = d_inode(child); 744 struct fuse_conn *fc = get_fuse_conn(child_inode); 745 struct inode *inode; 746 struct dentry *parent; 747 struct fuse_entry_out outarg; 748 struct qstr name; 749 int err; 750 751 if (!fc->export_support) 752 return ERR_PTR(-ESTALE); 753 754 name.len = 2; 755 name.name = ".."; 756 err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode), 757 &name, &outarg, &inode); 758 if (err) { 759 if (err == -ENOENT) 760 return ERR_PTR(-ESTALE); 761 return ERR_PTR(err); 762 } 763 764 parent = d_obtain_alias(inode); 765 if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID) 766 fuse_invalidate_entry_cache(parent); 767 768 return parent; 769 } 770 771 static const struct export_operations fuse_export_operations = { 772 .fh_to_dentry = fuse_fh_to_dentry, 773 .fh_to_parent = fuse_fh_to_parent, 774 .encode_fh = fuse_encode_fh, 775 .get_parent = fuse_get_parent, 776 }; 777 778 static const struct super_operations fuse_super_operations = { 779 .alloc_inode = fuse_alloc_inode, 780 .destroy_inode = fuse_destroy_inode, 781 .evict_inode = fuse_evict_inode, 782 .write_inode = fuse_write_inode, 783 .drop_inode = generic_delete_inode, 784 .remount_fs = fuse_remount_fs, 785 .put_super = fuse_put_super, 786 .umount_begin = fuse_umount_begin, 787 .statfs = fuse_statfs, 788 .show_options = fuse_show_options, 789 }; 790 791 static void sanitize_global_limit(unsigned *limit) 792 { 793 if (*limit == 0) 794 *limit = ((totalram_pages << PAGE_SHIFT) >> 13) / 795 sizeof(struct fuse_req); 796 797 if (*limit >= 1 << 16) 798 *limit = (1 << 16) - 1; 799 } 800 801 static int set_global_limit(const char *val, struct kernel_param *kp) 802 { 803 int rv; 804 805 rv = param_set_uint(val, kp); 806 if (rv) 807 return rv; 808 809 sanitize_global_limit((unsigned *)kp->arg); 810 811 return 0; 812 } 813 814 static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg) 815 { 816 int cap_sys_admin = capable(CAP_SYS_ADMIN); 817 818 if (arg->minor < 13) 819 return; 820 821 sanitize_global_limit(&max_user_bgreq); 822 sanitize_global_limit(&max_user_congthresh); 823 824 if (arg->max_background) { 825 fc->max_background = arg->max_background; 826 827 if (!cap_sys_admin && fc->max_background > max_user_bgreq) 828 fc->max_background = max_user_bgreq; 829 } 830 if (arg->congestion_threshold) { 831 fc->congestion_threshold = arg->congestion_threshold; 832 833 if (!cap_sys_admin && 834 fc->congestion_threshold > max_user_congthresh) 835 fc->congestion_threshold = max_user_congthresh; 836 } 837 } 838 839 static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req) 840 { 841 struct fuse_init_out *arg = &req->misc.init_out; 842 843 if (req->out.h.error || arg->major != FUSE_KERNEL_VERSION) 844 fc->conn_error = 1; 845 else { 846 unsigned long ra_pages; 847 848 process_init_limits(fc, arg); 849 850 if (arg->minor >= 6) { 851 ra_pages = arg->max_readahead / PAGE_CACHE_SIZE; 852 if (arg->flags & FUSE_ASYNC_READ) 853 fc->async_read = 1; 854 if (!(arg->flags & FUSE_POSIX_LOCKS)) 855 fc->no_lock = 1; 856 if (arg->minor >= 17) { 857 if (!(arg->flags & FUSE_FLOCK_LOCKS)) 858 fc->no_flock = 1; 859 } else { 860 if (!(arg->flags & FUSE_POSIX_LOCKS)) 861 fc->no_flock = 1; 862 } 863 if (arg->flags & FUSE_ATOMIC_O_TRUNC) 864 fc->atomic_o_trunc = 1; 865 if (arg->minor >= 9) { 866 /* LOOKUP has dependency on proto version */ 867 if (arg->flags & FUSE_EXPORT_SUPPORT) 868 fc->export_support = 1; 869 } 870 if (arg->flags & FUSE_BIG_WRITES) 871 fc->big_writes = 1; 872 if (arg->flags & FUSE_DONT_MASK) 873 fc->dont_mask = 1; 874 if (arg->flags & FUSE_AUTO_INVAL_DATA) 875 fc->auto_inval_data = 1; 876 if (arg->flags & FUSE_DO_READDIRPLUS) { 877 fc->do_readdirplus = 1; 878 if (arg->flags & FUSE_READDIRPLUS_AUTO) 879 fc->readdirplus_auto = 1; 880 } 881 if (arg->flags & FUSE_ASYNC_DIO) 882 fc->async_dio = 1; 883 if (arg->flags & FUSE_WRITEBACK_CACHE) 884 fc->writeback_cache = 1; 885 if (arg->time_gran && arg->time_gran <= 1000000000) 886 fc->sb->s_time_gran = arg->time_gran; 887 } else { 888 ra_pages = fc->max_read / PAGE_CACHE_SIZE; 889 fc->no_lock = 1; 890 fc->no_flock = 1; 891 } 892 893 fc->bdi.ra_pages = min(fc->bdi.ra_pages, ra_pages); 894 fc->minor = arg->minor; 895 fc->max_write = arg->minor < 5 ? 4096 : arg->max_write; 896 fc->max_write = max_t(unsigned, 4096, fc->max_write); 897 fc->conn_init = 1; 898 } 899 fuse_set_initialized(fc); 900 wake_up_all(&fc->blocked_waitq); 901 } 902 903 static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req) 904 { 905 struct fuse_init_in *arg = &req->misc.init_in; 906 907 arg->major = FUSE_KERNEL_VERSION; 908 arg->minor = FUSE_KERNEL_MINOR_VERSION; 909 arg->max_readahead = fc->bdi.ra_pages * PAGE_CACHE_SIZE; 910 arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC | 911 FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK | 912 FUSE_SPLICE_WRITE | FUSE_SPLICE_MOVE | FUSE_SPLICE_READ | 913 FUSE_FLOCK_LOCKS | FUSE_IOCTL_DIR | FUSE_AUTO_INVAL_DATA | 914 FUSE_DO_READDIRPLUS | FUSE_READDIRPLUS_AUTO | FUSE_ASYNC_DIO | 915 FUSE_WRITEBACK_CACHE | FUSE_NO_OPEN_SUPPORT; 916 req->in.h.opcode = FUSE_INIT; 917 req->in.numargs = 1; 918 req->in.args[0].size = sizeof(*arg); 919 req->in.args[0].value = arg; 920 req->out.numargs = 1; 921 /* Variable length argument used for backward compatibility 922 with interface version < 7.5. Rest of init_out is zeroed 923 by do_get_request(), so a short reply is not a problem */ 924 req->out.argvar = 1; 925 req->out.args[0].size = sizeof(struct fuse_init_out); 926 req->out.args[0].value = &req->misc.init_out; 927 req->end = process_init_reply; 928 fuse_request_send_background(fc, req); 929 } 930 931 static void fuse_free_conn(struct fuse_conn *fc) 932 { 933 kfree_rcu(fc, rcu); 934 } 935 936 static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb) 937 { 938 int err; 939 940 fc->bdi.name = "fuse"; 941 fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE; 942 /* fuse does it's own writeback accounting */ 943 fc->bdi.capabilities = BDI_CAP_NO_ACCT_WB | BDI_CAP_STRICTLIMIT; 944 945 err = bdi_init(&fc->bdi); 946 if (err) 947 return err; 948 949 fc->bdi_initialized = 1; 950 951 if (sb->s_bdev) { 952 err = bdi_register(&fc->bdi, NULL, "%u:%u-fuseblk", 953 MAJOR(fc->dev), MINOR(fc->dev)); 954 } else { 955 err = bdi_register_dev(&fc->bdi, fc->dev); 956 } 957 958 if (err) 959 return err; 960 961 /* 962 * For a single fuse filesystem use max 1% of dirty + 963 * writeback threshold. 964 * 965 * This gives about 1M of write buffer for memory maps on a 966 * machine with 1G and 10% dirty_ratio, which should be more 967 * than enough. 968 * 969 * Privileged users can raise it by writing to 970 * 971 * /sys/class/bdi/<bdi>/max_ratio 972 */ 973 bdi_set_max_ratio(&fc->bdi, 1); 974 975 return 0; 976 } 977 978 static int fuse_fill_super(struct super_block *sb, void *data, int silent) 979 { 980 struct fuse_conn *fc; 981 struct inode *root; 982 struct fuse_mount_data d; 983 struct file *file; 984 struct dentry *root_dentry; 985 struct fuse_req *init_req; 986 int err; 987 int is_bdev = sb->s_bdev != NULL; 988 989 err = -EINVAL; 990 if (sb->s_flags & MS_MANDLOCK) 991 goto err; 992 993 sb->s_flags &= ~(MS_NOSEC | MS_I_VERSION); 994 995 if (!parse_fuse_opt(data, &d, is_bdev)) 996 goto err; 997 998 if (is_bdev) { 999 #ifdef CONFIG_BLOCK 1000 err = -EINVAL; 1001 if (!sb_set_blocksize(sb, d.blksize)) 1002 goto err; 1003 #endif 1004 } else { 1005 sb->s_blocksize = PAGE_CACHE_SIZE; 1006 sb->s_blocksize_bits = PAGE_CACHE_SHIFT; 1007 } 1008 sb->s_magic = FUSE_SUPER_MAGIC; 1009 sb->s_op = &fuse_super_operations; 1010 sb->s_maxbytes = MAX_LFS_FILESIZE; 1011 sb->s_time_gran = 1; 1012 sb->s_export_op = &fuse_export_operations; 1013 1014 file = fget(d.fd); 1015 err = -EINVAL; 1016 if (!file) 1017 goto err; 1018 1019 if ((file->f_op != &fuse_dev_operations) || 1020 (file->f_cred->user_ns != &init_user_ns)) 1021 goto err_fput; 1022 1023 fc = kmalloc(sizeof(*fc), GFP_KERNEL); 1024 err = -ENOMEM; 1025 if (!fc) 1026 goto err_fput; 1027 1028 fuse_conn_init(fc); 1029 1030 fc->dev = sb->s_dev; 1031 fc->sb = sb; 1032 err = fuse_bdi_init(fc, sb); 1033 if (err) 1034 goto err_put_conn; 1035 1036 sb->s_bdi = &fc->bdi; 1037 1038 /* Handle umasking inside the fuse code */ 1039 if (sb->s_flags & MS_POSIXACL) 1040 fc->dont_mask = 1; 1041 sb->s_flags |= MS_POSIXACL; 1042 1043 fc->release = fuse_free_conn; 1044 fc->flags = d.flags; 1045 fc->user_id = d.user_id; 1046 fc->group_id = d.group_id; 1047 fc->max_read = max_t(unsigned, 4096, d.max_read); 1048 1049 /* Used by get_root_inode() */ 1050 sb->s_fs_info = fc; 1051 1052 err = -ENOMEM; 1053 root = fuse_get_root_inode(sb, d.rootmode); 1054 root_dentry = d_make_root(root); 1055 if (!root_dentry) 1056 goto err_put_conn; 1057 /* only now - we want root dentry with NULL ->d_op */ 1058 sb->s_d_op = &fuse_dentry_operations; 1059 1060 init_req = fuse_request_alloc(0); 1061 if (!init_req) 1062 goto err_put_root; 1063 init_req->background = 1; 1064 1065 if (is_bdev) { 1066 fc->destroy_req = fuse_request_alloc(0); 1067 if (!fc->destroy_req) 1068 goto err_free_init_req; 1069 } 1070 1071 mutex_lock(&fuse_mutex); 1072 err = -EINVAL; 1073 if (file->private_data) 1074 goto err_unlock; 1075 1076 err = fuse_ctl_add_conn(fc); 1077 if (err) 1078 goto err_unlock; 1079 1080 list_add_tail(&fc->entry, &fuse_conn_list); 1081 sb->s_root = root_dentry; 1082 fc->connected = 1; 1083 file->private_data = fuse_conn_get(fc); 1084 mutex_unlock(&fuse_mutex); 1085 /* 1086 * atomic_dec_and_test() in fput() provides the necessary 1087 * memory barrier for file->private_data to be visible on all 1088 * CPUs after this 1089 */ 1090 fput(file); 1091 1092 fuse_send_init(fc, init_req); 1093 1094 return 0; 1095 1096 err_unlock: 1097 mutex_unlock(&fuse_mutex); 1098 err_free_init_req: 1099 fuse_request_free(init_req); 1100 err_put_root: 1101 dput(root_dentry); 1102 err_put_conn: 1103 fuse_bdi_destroy(fc); 1104 fuse_conn_put(fc); 1105 err_fput: 1106 fput(file); 1107 err: 1108 return err; 1109 } 1110 1111 static struct dentry *fuse_mount(struct file_system_type *fs_type, 1112 int flags, const char *dev_name, 1113 void *raw_data) 1114 { 1115 return mount_nodev(fs_type, flags, raw_data, fuse_fill_super); 1116 } 1117 1118 static void fuse_kill_sb_anon(struct super_block *sb) 1119 { 1120 struct fuse_conn *fc = get_fuse_conn_super(sb); 1121 1122 if (fc) { 1123 down_write(&fc->killsb); 1124 fc->sb = NULL; 1125 up_write(&fc->killsb); 1126 } 1127 1128 kill_anon_super(sb); 1129 } 1130 1131 static struct file_system_type fuse_fs_type = { 1132 .owner = THIS_MODULE, 1133 .name = "fuse", 1134 .fs_flags = FS_HAS_SUBTYPE, 1135 .mount = fuse_mount, 1136 .kill_sb = fuse_kill_sb_anon, 1137 }; 1138 MODULE_ALIAS_FS("fuse"); 1139 1140 #ifdef CONFIG_BLOCK 1141 static struct dentry *fuse_mount_blk(struct file_system_type *fs_type, 1142 int flags, const char *dev_name, 1143 void *raw_data) 1144 { 1145 return mount_bdev(fs_type, flags, dev_name, raw_data, fuse_fill_super); 1146 } 1147 1148 static void fuse_kill_sb_blk(struct super_block *sb) 1149 { 1150 struct fuse_conn *fc = get_fuse_conn_super(sb); 1151 1152 if (fc) { 1153 down_write(&fc->killsb); 1154 fc->sb = NULL; 1155 up_write(&fc->killsb); 1156 } 1157 1158 kill_block_super(sb); 1159 } 1160 1161 static struct file_system_type fuseblk_fs_type = { 1162 .owner = THIS_MODULE, 1163 .name = "fuseblk", 1164 .mount = fuse_mount_blk, 1165 .kill_sb = fuse_kill_sb_blk, 1166 .fs_flags = FS_REQUIRES_DEV | FS_HAS_SUBTYPE, 1167 }; 1168 MODULE_ALIAS_FS("fuseblk"); 1169 1170 static inline int register_fuseblk(void) 1171 { 1172 return register_filesystem(&fuseblk_fs_type); 1173 } 1174 1175 static inline void unregister_fuseblk(void) 1176 { 1177 unregister_filesystem(&fuseblk_fs_type); 1178 } 1179 #else 1180 static inline int register_fuseblk(void) 1181 { 1182 return 0; 1183 } 1184 1185 static inline void unregister_fuseblk(void) 1186 { 1187 } 1188 #endif 1189 1190 static void fuse_inode_init_once(void *foo) 1191 { 1192 struct inode *inode = foo; 1193 1194 inode_init_once(inode); 1195 } 1196 1197 static int __init fuse_fs_init(void) 1198 { 1199 int err; 1200 1201 fuse_inode_cachep = kmem_cache_create("fuse_inode", 1202 sizeof(struct fuse_inode), 1203 0, SLAB_HWCACHE_ALIGN, 1204 fuse_inode_init_once); 1205 err = -ENOMEM; 1206 if (!fuse_inode_cachep) 1207 goto out; 1208 1209 err = register_fuseblk(); 1210 if (err) 1211 goto out2; 1212 1213 err = register_filesystem(&fuse_fs_type); 1214 if (err) 1215 goto out3; 1216 1217 return 0; 1218 1219 out3: 1220 unregister_fuseblk(); 1221 out2: 1222 kmem_cache_destroy(fuse_inode_cachep); 1223 out: 1224 return err; 1225 } 1226 1227 static void fuse_fs_cleanup(void) 1228 { 1229 unregister_filesystem(&fuse_fs_type); 1230 unregister_fuseblk(); 1231 1232 /* 1233 * Make sure all delayed rcu free inodes are flushed before we 1234 * destroy cache. 1235 */ 1236 rcu_barrier(); 1237 kmem_cache_destroy(fuse_inode_cachep); 1238 } 1239 1240 static struct kobject *fuse_kobj; 1241 static struct kobject *connections_kobj; 1242 1243 static int fuse_sysfs_init(void) 1244 { 1245 int err; 1246 1247 fuse_kobj = kobject_create_and_add("fuse", fs_kobj); 1248 if (!fuse_kobj) { 1249 err = -ENOMEM; 1250 goto out_err; 1251 } 1252 1253 connections_kobj = kobject_create_and_add("connections", fuse_kobj); 1254 if (!connections_kobj) { 1255 err = -ENOMEM; 1256 goto out_fuse_unregister; 1257 } 1258 1259 return 0; 1260 1261 out_fuse_unregister: 1262 kobject_put(fuse_kobj); 1263 out_err: 1264 return err; 1265 } 1266 1267 static void fuse_sysfs_cleanup(void) 1268 { 1269 kobject_put(connections_kobj); 1270 kobject_put(fuse_kobj); 1271 } 1272 1273 static int __init fuse_init(void) 1274 { 1275 int res; 1276 1277 printk(KERN_INFO "fuse init (API version %i.%i)\n", 1278 FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION); 1279 1280 INIT_LIST_HEAD(&fuse_conn_list); 1281 res = fuse_fs_init(); 1282 if (res) 1283 goto err; 1284 1285 res = fuse_dev_init(); 1286 if (res) 1287 goto err_fs_cleanup; 1288 1289 res = fuse_sysfs_init(); 1290 if (res) 1291 goto err_dev_cleanup; 1292 1293 res = fuse_ctl_init(); 1294 if (res) 1295 goto err_sysfs_cleanup; 1296 1297 sanitize_global_limit(&max_user_bgreq); 1298 sanitize_global_limit(&max_user_congthresh); 1299 1300 return 0; 1301 1302 err_sysfs_cleanup: 1303 fuse_sysfs_cleanup(); 1304 err_dev_cleanup: 1305 fuse_dev_cleanup(); 1306 err_fs_cleanup: 1307 fuse_fs_cleanup(); 1308 err: 1309 return res; 1310 } 1311 1312 static void __exit fuse_exit(void) 1313 { 1314 printk(KERN_DEBUG "fuse exit\n"); 1315 1316 fuse_ctl_cleanup(); 1317 fuse_sysfs_cleanup(); 1318 fuse_fs_cleanup(); 1319 fuse_dev_cleanup(); 1320 } 1321 1322 module_init(fuse_init); 1323 module_exit(fuse_exit); 1324