1 /* 2 FUSE: Filesystem in Userspace 3 Copyright (C) 2001-2008 Miklos Szeredi <miklos@szeredi.hu> 4 5 This program can be distributed under the terms of the GNU GPL. 6 See the file COPYING. 7 */ 8 9 #include "fuse_i.h" 10 11 #include <linux/pagemap.h> 12 #include <linux/slab.h> 13 #include <linux/file.h> 14 #include <linux/seq_file.h> 15 #include <linux/init.h> 16 #include <linux/module.h> 17 #include <linux/moduleparam.h> 18 #include <linux/parser.h> 19 #include <linux/statfs.h> 20 #include <linux/random.h> 21 #include <linux/sched.h> 22 #include <linux/exportfs.h> 23 24 MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>"); 25 MODULE_DESCRIPTION("Filesystem in Userspace"); 26 MODULE_LICENSE("GPL"); 27 28 static struct kmem_cache *fuse_inode_cachep; 29 struct list_head fuse_conn_list; 30 DEFINE_MUTEX(fuse_mutex); 31 32 static int set_global_limit(const char *val, struct kernel_param *kp); 33 34 unsigned max_user_bgreq; 35 module_param_call(max_user_bgreq, set_global_limit, param_get_uint, 36 &max_user_bgreq, 0644); 37 __MODULE_PARM_TYPE(max_user_bgreq, "uint"); 38 MODULE_PARM_DESC(max_user_bgreq, 39 "Global limit for the maximum number of backgrounded requests an " 40 "unprivileged user can set"); 41 42 unsigned max_user_congthresh; 43 module_param_call(max_user_congthresh, set_global_limit, param_get_uint, 44 &max_user_congthresh, 0644); 45 __MODULE_PARM_TYPE(max_user_congthresh, "uint"); 46 MODULE_PARM_DESC(max_user_congthresh, 47 "Global limit for the maximum congestion threshold an " 48 "unprivileged user can set"); 49 50 #define FUSE_SUPER_MAGIC 0x65735546 51 52 #define FUSE_DEFAULT_BLKSIZE 512 53 54 /** Maximum number of outstanding background requests */ 55 #define FUSE_DEFAULT_MAX_BACKGROUND 12 56 57 /** Congestion starts at 75% of maximum */ 58 #define FUSE_DEFAULT_CONGESTION_THRESHOLD (FUSE_DEFAULT_MAX_BACKGROUND * 3 / 4) 59 60 struct fuse_mount_data { 61 int fd; 62 unsigned rootmode; 63 kuid_t user_id; 64 kgid_t group_id; 65 unsigned fd_present:1; 66 unsigned rootmode_present:1; 67 unsigned user_id_present:1; 68 unsigned group_id_present:1; 69 unsigned flags; 70 unsigned max_read; 71 unsigned blksize; 72 }; 73 74 struct fuse_forget_link *fuse_alloc_forget(void) 75 { 76 return kzalloc(sizeof(struct fuse_forget_link), GFP_KERNEL); 77 } 78 79 static struct inode *fuse_alloc_inode(struct super_block *sb) 80 { 81 struct inode *inode; 82 struct fuse_inode *fi; 83 84 inode = kmem_cache_alloc(fuse_inode_cachep, GFP_KERNEL); 85 if (!inode) 86 return NULL; 87 88 fi = get_fuse_inode(inode); 89 fi->i_time = 0; 90 fi->nodeid = 0; 91 fi->nlookup = 0; 92 fi->attr_version = 0; 93 fi->writectr = 0; 94 fi->orig_ino = 0; 95 fi->state = 0; 96 INIT_LIST_HEAD(&fi->write_files); 97 INIT_LIST_HEAD(&fi->queued_writes); 98 INIT_LIST_HEAD(&fi->writepages); 99 init_waitqueue_head(&fi->page_waitq); 100 fi->forget = fuse_alloc_forget(); 101 if (!fi->forget) { 102 kmem_cache_free(fuse_inode_cachep, inode); 103 return NULL; 104 } 105 106 return inode; 107 } 108 109 static void fuse_i_callback(struct rcu_head *head) 110 { 111 struct inode *inode = container_of(head, struct inode, i_rcu); 112 kmem_cache_free(fuse_inode_cachep, inode); 113 } 114 115 static void fuse_destroy_inode(struct inode *inode) 116 { 117 struct fuse_inode *fi = get_fuse_inode(inode); 118 BUG_ON(!list_empty(&fi->write_files)); 119 BUG_ON(!list_empty(&fi->queued_writes)); 120 kfree(fi->forget); 121 call_rcu(&inode->i_rcu, fuse_i_callback); 122 } 123 124 static void fuse_evict_inode(struct inode *inode) 125 { 126 truncate_inode_pages_final(&inode->i_data); 127 clear_inode(inode); 128 if (inode->i_sb->s_flags & MS_ACTIVE) { 129 struct fuse_conn *fc = get_fuse_conn(inode); 130 struct fuse_inode *fi = get_fuse_inode(inode); 131 fuse_queue_forget(fc, fi->forget, fi->nodeid, fi->nlookup); 132 fi->forget = NULL; 133 } 134 } 135 136 static int fuse_remount_fs(struct super_block *sb, int *flags, char *data) 137 { 138 sync_filesystem(sb); 139 if (*flags & MS_MANDLOCK) 140 return -EINVAL; 141 142 return 0; 143 } 144 145 /* 146 * ino_t is 32-bits on 32-bit arch. We have to squash the 64-bit value down 147 * so that it will fit. 148 */ 149 static ino_t fuse_squash_ino(u64 ino64) 150 { 151 ino_t ino = (ino_t) ino64; 152 if (sizeof(ino_t) < sizeof(u64)) 153 ino ^= ino64 >> (sizeof(u64) - sizeof(ino_t)) * 8; 154 return ino; 155 } 156 157 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr, 158 u64 attr_valid) 159 { 160 struct fuse_conn *fc = get_fuse_conn(inode); 161 struct fuse_inode *fi = get_fuse_inode(inode); 162 163 fi->attr_version = ++fc->attr_version; 164 fi->i_time = attr_valid; 165 166 inode->i_ino = fuse_squash_ino(attr->ino); 167 inode->i_mode = (inode->i_mode & S_IFMT) | (attr->mode & 07777); 168 set_nlink(inode, attr->nlink); 169 inode->i_uid = make_kuid(&init_user_ns, attr->uid); 170 inode->i_gid = make_kgid(&init_user_ns, attr->gid); 171 inode->i_blocks = attr->blocks; 172 inode->i_atime.tv_sec = attr->atime; 173 inode->i_atime.tv_nsec = attr->atimensec; 174 /* mtime from server may be stale due to local buffered write */ 175 if (!fc->writeback_cache || !S_ISREG(inode->i_mode)) { 176 inode->i_mtime.tv_sec = attr->mtime; 177 inode->i_mtime.tv_nsec = attr->mtimensec; 178 inode->i_ctime.tv_sec = attr->ctime; 179 inode->i_ctime.tv_nsec = attr->ctimensec; 180 } 181 182 if (attr->blksize != 0) 183 inode->i_blkbits = ilog2(attr->blksize); 184 else 185 inode->i_blkbits = inode->i_sb->s_blocksize_bits; 186 187 /* 188 * Don't set the sticky bit in i_mode, unless we want the VFS 189 * to check permissions. This prevents failures due to the 190 * check in may_delete(). 191 */ 192 fi->orig_i_mode = inode->i_mode; 193 if (!(fc->flags & FUSE_DEFAULT_PERMISSIONS)) 194 inode->i_mode &= ~S_ISVTX; 195 196 fi->orig_ino = attr->ino; 197 } 198 199 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr, 200 u64 attr_valid, u64 attr_version) 201 { 202 struct fuse_conn *fc = get_fuse_conn(inode); 203 struct fuse_inode *fi = get_fuse_inode(inode); 204 bool is_wb = fc->writeback_cache; 205 loff_t oldsize; 206 struct timespec old_mtime; 207 208 spin_lock(&fc->lock); 209 if ((attr_version != 0 && fi->attr_version > attr_version) || 210 test_bit(FUSE_I_SIZE_UNSTABLE, &fi->state)) { 211 spin_unlock(&fc->lock); 212 return; 213 } 214 215 old_mtime = inode->i_mtime; 216 fuse_change_attributes_common(inode, attr, attr_valid); 217 218 oldsize = inode->i_size; 219 /* 220 * In case of writeback_cache enabled, the cached writes beyond EOF 221 * extend local i_size without keeping userspace server in sync. So, 222 * attr->size coming from server can be stale. We cannot trust it. 223 */ 224 if (!is_wb || !S_ISREG(inode->i_mode)) 225 i_size_write(inode, attr->size); 226 spin_unlock(&fc->lock); 227 228 if (!is_wb && S_ISREG(inode->i_mode)) { 229 bool inval = false; 230 231 if (oldsize != attr->size) { 232 truncate_pagecache(inode, attr->size); 233 inval = true; 234 } else if (fc->auto_inval_data) { 235 struct timespec new_mtime = { 236 .tv_sec = attr->mtime, 237 .tv_nsec = attr->mtimensec, 238 }; 239 240 /* 241 * Auto inval mode also checks and invalidates if mtime 242 * has changed. 243 */ 244 if (!timespec_equal(&old_mtime, &new_mtime)) 245 inval = true; 246 } 247 248 if (inval) 249 invalidate_inode_pages2(inode->i_mapping); 250 } 251 } 252 253 static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr) 254 { 255 inode->i_mode = attr->mode & S_IFMT; 256 inode->i_size = attr->size; 257 inode->i_mtime.tv_sec = attr->mtime; 258 inode->i_mtime.tv_nsec = attr->mtimensec; 259 inode->i_ctime.tv_sec = attr->ctime; 260 inode->i_ctime.tv_nsec = attr->ctimensec; 261 if (S_ISREG(inode->i_mode)) { 262 fuse_init_common(inode); 263 fuse_init_file_inode(inode); 264 } else if (S_ISDIR(inode->i_mode)) 265 fuse_init_dir(inode); 266 else if (S_ISLNK(inode->i_mode)) 267 fuse_init_symlink(inode); 268 else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) || 269 S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) { 270 fuse_init_common(inode); 271 init_special_inode(inode, inode->i_mode, 272 new_decode_dev(attr->rdev)); 273 } else 274 BUG(); 275 } 276 277 int fuse_inode_eq(struct inode *inode, void *_nodeidp) 278 { 279 u64 nodeid = *(u64 *) _nodeidp; 280 if (get_node_id(inode) == nodeid) 281 return 1; 282 else 283 return 0; 284 } 285 286 static int fuse_inode_set(struct inode *inode, void *_nodeidp) 287 { 288 u64 nodeid = *(u64 *) _nodeidp; 289 get_fuse_inode(inode)->nodeid = nodeid; 290 return 0; 291 } 292 293 struct inode *fuse_iget(struct super_block *sb, u64 nodeid, 294 int generation, struct fuse_attr *attr, 295 u64 attr_valid, u64 attr_version) 296 { 297 struct inode *inode; 298 struct fuse_inode *fi; 299 struct fuse_conn *fc = get_fuse_conn_super(sb); 300 301 retry: 302 inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid); 303 if (!inode) 304 return NULL; 305 306 if ((inode->i_state & I_NEW)) { 307 inode->i_flags |= S_NOATIME; 308 if (!fc->writeback_cache || !S_ISREG(attr->mode)) 309 inode->i_flags |= S_NOCMTIME; 310 inode->i_generation = generation; 311 inode->i_data.backing_dev_info = &fc->bdi; 312 fuse_init_inode(inode, attr); 313 unlock_new_inode(inode); 314 } else if ((inode->i_mode ^ attr->mode) & S_IFMT) { 315 /* Inode has changed type, any I/O on the old should fail */ 316 make_bad_inode(inode); 317 iput(inode); 318 goto retry; 319 } 320 321 fi = get_fuse_inode(inode); 322 spin_lock(&fc->lock); 323 fi->nlookup++; 324 spin_unlock(&fc->lock); 325 fuse_change_attributes(inode, attr, attr_valid, attr_version); 326 327 return inode; 328 } 329 330 int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid, 331 loff_t offset, loff_t len) 332 { 333 struct inode *inode; 334 pgoff_t pg_start; 335 pgoff_t pg_end; 336 337 inode = ilookup5(sb, nodeid, fuse_inode_eq, &nodeid); 338 if (!inode) 339 return -ENOENT; 340 341 fuse_invalidate_attr(inode); 342 if (offset >= 0) { 343 pg_start = offset >> PAGE_CACHE_SHIFT; 344 if (len <= 0) 345 pg_end = -1; 346 else 347 pg_end = (offset + len - 1) >> PAGE_CACHE_SHIFT; 348 invalidate_inode_pages2_range(inode->i_mapping, 349 pg_start, pg_end); 350 } 351 iput(inode); 352 return 0; 353 } 354 355 static void fuse_umount_begin(struct super_block *sb) 356 { 357 fuse_abort_conn(get_fuse_conn_super(sb)); 358 } 359 360 static void fuse_send_destroy(struct fuse_conn *fc) 361 { 362 struct fuse_req *req = fc->destroy_req; 363 if (req && fc->conn_init) { 364 fc->destroy_req = NULL; 365 req->in.h.opcode = FUSE_DESTROY; 366 req->force = 1; 367 req->background = 0; 368 fuse_request_send(fc, req); 369 fuse_put_request(fc, req); 370 } 371 } 372 373 static void fuse_bdi_destroy(struct fuse_conn *fc) 374 { 375 if (fc->bdi_initialized) 376 bdi_destroy(&fc->bdi); 377 } 378 379 void fuse_conn_kill(struct fuse_conn *fc) 380 { 381 spin_lock(&fc->lock); 382 fc->connected = 0; 383 fc->blocked = 0; 384 fc->initialized = 1; 385 spin_unlock(&fc->lock); 386 /* Flush all readers on this fs */ 387 kill_fasync(&fc->fasync, SIGIO, POLL_IN); 388 wake_up_all(&fc->waitq); 389 wake_up_all(&fc->blocked_waitq); 390 wake_up_all(&fc->reserved_req_waitq); 391 } 392 EXPORT_SYMBOL_GPL(fuse_conn_kill); 393 394 static void fuse_put_super(struct super_block *sb) 395 { 396 struct fuse_conn *fc = get_fuse_conn_super(sb); 397 398 fuse_send_destroy(fc); 399 400 fuse_conn_kill(fc); 401 mutex_lock(&fuse_mutex); 402 list_del(&fc->entry); 403 fuse_ctl_remove_conn(fc); 404 mutex_unlock(&fuse_mutex); 405 fuse_bdi_destroy(fc); 406 407 fuse_conn_put(fc); 408 } 409 410 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr) 411 { 412 stbuf->f_type = FUSE_SUPER_MAGIC; 413 stbuf->f_bsize = attr->bsize; 414 stbuf->f_frsize = attr->frsize; 415 stbuf->f_blocks = attr->blocks; 416 stbuf->f_bfree = attr->bfree; 417 stbuf->f_bavail = attr->bavail; 418 stbuf->f_files = attr->files; 419 stbuf->f_ffree = attr->ffree; 420 stbuf->f_namelen = attr->namelen; 421 /* fsid is left zero */ 422 } 423 424 static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf) 425 { 426 struct super_block *sb = dentry->d_sb; 427 struct fuse_conn *fc = get_fuse_conn_super(sb); 428 struct fuse_req *req; 429 struct fuse_statfs_out outarg; 430 int err; 431 432 if (!fuse_allow_current_process(fc)) { 433 buf->f_type = FUSE_SUPER_MAGIC; 434 return 0; 435 } 436 437 req = fuse_get_req_nopages(fc); 438 if (IS_ERR(req)) 439 return PTR_ERR(req); 440 441 memset(&outarg, 0, sizeof(outarg)); 442 req->in.numargs = 0; 443 req->in.h.opcode = FUSE_STATFS; 444 req->in.h.nodeid = get_node_id(dentry->d_inode); 445 req->out.numargs = 1; 446 req->out.args[0].size = 447 fc->minor < 4 ? FUSE_COMPAT_STATFS_SIZE : sizeof(outarg); 448 req->out.args[0].value = &outarg; 449 fuse_request_send(fc, req); 450 err = req->out.h.error; 451 if (!err) 452 convert_fuse_statfs(buf, &outarg.st); 453 fuse_put_request(fc, req); 454 return err; 455 } 456 457 enum { 458 OPT_FD, 459 OPT_ROOTMODE, 460 OPT_USER_ID, 461 OPT_GROUP_ID, 462 OPT_DEFAULT_PERMISSIONS, 463 OPT_ALLOW_OTHER, 464 OPT_MAX_READ, 465 OPT_BLKSIZE, 466 OPT_ERR 467 }; 468 469 static const match_table_t tokens = { 470 {OPT_FD, "fd=%u"}, 471 {OPT_ROOTMODE, "rootmode=%o"}, 472 {OPT_USER_ID, "user_id=%u"}, 473 {OPT_GROUP_ID, "group_id=%u"}, 474 {OPT_DEFAULT_PERMISSIONS, "default_permissions"}, 475 {OPT_ALLOW_OTHER, "allow_other"}, 476 {OPT_MAX_READ, "max_read=%u"}, 477 {OPT_BLKSIZE, "blksize=%u"}, 478 {OPT_ERR, NULL} 479 }; 480 481 static int fuse_match_uint(substring_t *s, unsigned int *res) 482 { 483 int err = -ENOMEM; 484 char *buf = match_strdup(s); 485 if (buf) { 486 err = kstrtouint(buf, 10, res); 487 kfree(buf); 488 } 489 return err; 490 } 491 492 static int parse_fuse_opt(char *opt, struct fuse_mount_data *d, int is_bdev) 493 { 494 char *p; 495 memset(d, 0, sizeof(struct fuse_mount_data)); 496 d->max_read = ~0; 497 d->blksize = FUSE_DEFAULT_BLKSIZE; 498 499 while ((p = strsep(&opt, ",")) != NULL) { 500 int token; 501 int value; 502 unsigned uv; 503 substring_t args[MAX_OPT_ARGS]; 504 if (!*p) 505 continue; 506 507 token = match_token(p, tokens, args); 508 switch (token) { 509 case OPT_FD: 510 if (match_int(&args[0], &value)) 511 return 0; 512 d->fd = value; 513 d->fd_present = 1; 514 break; 515 516 case OPT_ROOTMODE: 517 if (match_octal(&args[0], &value)) 518 return 0; 519 if (!fuse_valid_type(value)) 520 return 0; 521 d->rootmode = value; 522 d->rootmode_present = 1; 523 break; 524 525 case OPT_USER_ID: 526 if (fuse_match_uint(&args[0], &uv)) 527 return 0; 528 d->user_id = make_kuid(current_user_ns(), uv); 529 if (!uid_valid(d->user_id)) 530 return 0; 531 d->user_id_present = 1; 532 break; 533 534 case OPT_GROUP_ID: 535 if (fuse_match_uint(&args[0], &uv)) 536 return 0; 537 d->group_id = make_kgid(current_user_ns(), uv); 538 if (!gid_valid(d->group_id)) 539 return 0; 540 d->group_id_present = 1; 541 break; 542 543 case OPT_DEFAULT_PERMISSIONS: 544 d->flags |= FUSE_DEFAULT_PERMISSIONS; 545 break; 546 547 case OPT_ALLOW_OTHER: 548 d->flags |= FUSE_ALLOW_OTHER; 549 break; 550 551 case OPT_MAX_READ: 552 if (match_int(&args[0], &value)) 553 return 0; 554 d->max_read = value; 555 break; 556 557 case OPT_BLKSIZE: 558 if (!is_bdev || match_int(&args[0], &value)) 559 return 0; 560 d->blksize = value; 561 break; 562 563 default: 564 return 0; 565 } 566 } 567 568 if (!d->fd_present || !d->rootmode_present || 569 !d->user_id_present || !d->group_id_present) 570 return 0; 571 572 return 1; 573 } 574 575 static int fuse_show_options(struct seq_file *m, struct dentry *root) 576 { 577 struct super_block *sb = root->d_sb; 578 struct fuse_conn *fc = get_fuse_conn_super(sb); 579 580 seq_printf(m, ",user_id=%u", from_kuid_munged(&init_user_ns, fc->user_id)); 581 seq_printf(m, ",group_id=%u", from_kgid_munged(&init_user_ns, fc->group_id)); 582 if (fc->flags & FUSE_DEFAULT_PERMISSIONS) 583 seq_puts(m, ",default_permissions"); 584 if (fc->flags & FUSE_ALLOW_OTHER) 585 seq_puts(m, ",allow_other"); 586 if (fc->max_read != ~0) 587 seq_printf(m, ",max_read=%u", fc->max_read); 588 if (sb->s_bdev && sb->s_blocksize != FUSE_DEFAULT_BLKSIZE) 589 seq_printf(m, ",blksize=%lu", sb->s_blocksize); 590 return 0; 591 } 592 593 void fuse_conn_init(struct fuse_conn *fc) 594 { 595 memset(fc, 0, sizeof(*fc)); 596 spin_lock_init(&fc->lock); 597 init_rwsem(&fc->killsb); 598 atomic_set(&fc->count, 1); 599 init_waitqueue_head(&fc->waitq); 600 init_waitqueue_head(&fc->blocked_waitq); 601 init_waitqueue_head(&fc->reserved_req_waitq); 602 INIT_LIST_HEAD(&fc->pending); 603 INIT_LIST_HEAD(&fc->processing); 604 INIT_LIST_HEAD(&fc->io); 605 INIT_LIST_HEAD(&fc->interrupts); 606 INIT_LIST_HEAD(&fc->bg_queue); 607 INIT_LIST_HEAD(&fc->entry); 608 fc->forget_list_tail = &fc->forget_list_head; 609 atomic_set(&fc->num_waiting, 0); 610 fc->max_background = FUSE_DEFAULT_MAX_BACKGROUND; 611 fc->congestion_threshold = FUSE_DEFAULT_CONGESTION_THRESHOLD; 612 fc->khctr = 0; 613 fc->polled_files = RB_ROOT; 614 fc->reqctr = 0; 615 fc->blocked = 0; 616 fc->initialized = 0; 617 fc->attr_version = 1; 618 get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key)); 619 } 620 EXPORT_SYMBOL_GPL(fuse_conn_init); 621 622 void fuse_conn_put(struct fuse_conn *fc) 623 { 624 if (atomic_dec_and_test(&fc->count)) { 625 if (fc->destroy_req) 626 fuse_request_free(fc->destroy_req); 627 fc->release(fc); 628 } 629 } 630 EXPORT_SYMBOL_GPL(fuse_conn_put); 631 632 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc) 633 { 634 atomic_inc(&fc->count); 635 return fc; 636 } 637 EXPORT_SYMBOL_GPL(fuse_conn_get); 638 639 static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned mode) 640 { 641 struct fuse_attr attr; 642 memset(&attr, 0, sizeof(attr)); 643 644 attr.mode = mode; 645 attr.ino = FUSE_ROOT_ID; 646 attr.nlink = 1; 647 return fuse_iget(sb, 1, 0, &attr, 0, 0); 648 } 649 650 struct fuse_inode_handle { 651 u64 nodeid; 652 u32 generation; 653 }; 654 655 static struct dentry *fuse_get_dentry(struct super_block *sb, 656 struct fuse_inode_handle *handle) 657 { 658 struct fuse_conn *fc = get_fuse_conn_super(sb); 659 struct inode *inode; 660 struct dentry *entry; 661 int err = -ESTALE; 662 663 if (handle->nodeid == 0) 664 goto out_err; 665 666 inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid); 667 if (!inode) { 668 struct fuse_entry_out outarg; 669 struct qstr name; 670 671 if (!fc->export_support) 672 goto out_err; 673 674 name.len = 1; 675 name.name = "."; 676 err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg, 677 &inode); 678 if (err && err != -ENOENT) 679 goto out_err; 680 if (err || !inode) { 681 err = -ESTALE; 682 goto out_err; 683 } 684 err = -EIO; 685 if (get_node_id(inode) != handle->nodeid) 686 goto out_iput; 687 } 688 err = -ESTALE; 689 if (inode->i_generation != handle->generation) 690 goto out_iput; 691 692 entry = d_obtain_alias(inode); 693 if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID) 694 fuse_invalidate_entry_cache(entry); 695 696 return entry; 697 698 out_iput: 699 iput(inode); 700 out_err: 701 return ERR_PTR(err); 702 } 703 704 static int fuse_encode_fh(struct inode *inode, u32 *fh, int *max_len, 705 struct inode *parent) 706 { 707 int len = parent ? 6 : 3; 708 u64 nodeid; 709 u32 generation; 710 711 if (*max_len < len) { 712 *max_len = len; 713 return FILEID_INVALID; 714 } 715 716 nodeid = get_fuse_inode(inode)->nodeid; 717 generation = inode->i_generation; 718 719 fh[0] = (u32)(nodeid >> 32); 720 fh[1] = (u32)(nodeid & 0xffffffff); 721 fh[2] = generation; 722 723 if (parent) { 724 nodeid = get_fuse_inode(parent)->nodeid; 725 generation = parent->i_generation; 726 727 fh[3] = (u32)(nodeid >> 32); 728 fh[4] = (u32)(nodeid & 0xffffffff); 729 fh[5] = generation; 730 } 731 732 *max_len = len; 733 return parent ? 0x82 : 0x81; 734 } 735 736 static struct dentry *fuse_fh_to_dentry(struct super_block *sb, 737 struct fid *fid, int fh_len, int fh_type) 738 { 739 struct fuse_inode_handle handle; 740 741 if ((fh_type != 0x81 && fh_type != 0x82) || fh_len < 3) 742 return NULL; 743 744 handle.nodeid = (u64) fid->raw[0] << 32; 745 handle.nodeid |= (u64) fid->raw[1]; 746 handle.generation = fid->raw[2]; 747 return fuse_get_dentry(sb, &handle); 748 } 749 750 static struct dentry *fuse_fh_to_parent(struct super_block *sb, 751 struct fid *fid, int fh_len, int fh_type) 752 { 753 struct fuse_inode_handle parent; 754 755 if (fh_type != 0x82 || fh_len < 6) 756 return NULL; 757 758 parent.nodeid = (u64) fid->raw[3] << 32; 759 parent.nodeid |= (u64) fid->raw[4]; 760 parent.generation = fid->raw[5]; 761 return fuse_get_dentry(sb, &parent); 762 } 763 764 static struct dentry *fuse_get_parent(struct dentry *child) 765 { 766 struct inode *child_inode = child->d_inode; 767 struct fuse_conn *fc = get_fuse_conn(child_inode); 768 struct inode *inode; 769 struct dentry *parent; 770 struct fuse_entry_out outarg; 771 struct qstr name; 772 int err; 773 774 if (!fc->export_support) 775 return ERR_PTR(-ESTALE); 776 777 name.len = 2; 778 name.name = ".."; 779 err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode), 780 &name, &outarg, &inode); 781 if (err) { 782 if (err == -ENOENT) 783 return ERR_PTR(-ESTALE); 784 return ERR_PTR(err); 785 } 786 787 parent = d_obtain_alias(inode); 788 if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID) 789 fuse_invalidate_entry_cache(parent); 790 791 return parent; 792 } 793 794 static const struct export_operations fuse_export_operations = { 795 .fh_to_dentry = fuse_fh_to_dentry, 796 .fh_to_parent = fuse_fh_to_parent, 797 .encode_fh = fuse_encode_fh, 798 .get_parent = fuse_get_parent, 799 }; 800 801 static const struct super_operations fuse_super_operations = { 802 .alloc_inode = fuse_alloc_inode, 803 .destroy_inode = fuse_destroy_inode, 804 .evict_inode = fuse_evict_inode, 805 .write_inode = fuse_write_inode, 806 .drop_inode = generic_delete_inode, 807 .remount_fs = fuse_remount_fs, 808 .put_super = fuse_put_super, 809 .umount_begin = fuse_umount_begin, 810 .statfs = fuse_statfs, 811 .show_options = fuse_show_options, 812 }; 813 814 static void sanitize_global_limit(unsigned *limit) 815 { 816 if (*limit == 0) 817 *limit = ((totalram_pages << PAGE_SHIFT) >> 13) / 818 sizeof(struct fuse_req); 819 820 if (*limit >= 1 << 16) 821 *limit = (1 << 16) - 1; 822 } 823 824 static int set_global_limit(const char *val, struct kernel_param *kp) 825 { 826 int rv; 827 828 rv = param_set_uint(val, kp); 829 if (rv) 830 return rv; 831 832 sanitize_global_limit((unsigned *)kp->arg); 833 834 return 0; 835 } 836 837 static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg) 838 { 839 int cap_sys_admin = capable(CAP_SYS_ADMIN); 840 841 if (arg->minor < 13) 842 return; 843 844 sanitize_global_limit(&max_user_bgreq); 845 sanitize_global_limit(&max_user_congthresh); 846 847 if (arg->max_background) { 848 fc->max_background = arg->max_background; 849 850 if (!cap_sys_admin && fc->max_background > max_user_bgreq) 851 fc->max_background = max_user_bgreq; 852 } 853 if (arg->congestion_threshold) { 854 fc->congestion_threshold = arg->congestion_threshold; 855 856 if (!cap_sys_admin && 857 fc->congestion_threshold > max_user_congthresh) 858 fc->congestion_threshold = max_user_congthresh; 859 } 860 } 861 862 static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req) 863 { 864 struct fuse_init_out *arg = &req->misc.init_out; 865 866 if (req->out.h.error || arg->major != FUSE_KERNEL_VERSION) 867 fc->conn_error = 1; 868 else { 869 unsigned long ra_pages; 870 871 process_init_limits(fc, arg); 872 873 if (arg->minor >= 6) { 874 ra_pages = arg->max_readahead / PAGE_CACHE_SIZE; 875 if (arg->flags & FUSE_ASYNC_READ) 876 fc->async_read = 1; 877 if (!(arg->flags & FUSE_POSIX_LOCKS)) 878 fc->no_lock = 1; 879 if (arg->minor >= 17) { 880 if (!(arg->flags & FUSE_FLOCK_LOCKS)) 881 fc->no_flock = 1; 882 } else { 883 if (!(arg->flags & FUSE_POSIX_LOCKS)) 884 fc->no_flock = 1; 885 } 886 if (arg->flags & FUSE_ATOMIC_O_TRUNC) 887 fc->atomic_o_trunc = 1; 888 if (arg->minor >= 9) { 889 /* LOOKUP has dependency on proto version */ 890 if (arg->flags & FUSE_EXPORT_SUPPORT) 891 fc->export_support = 1; 892 } 893 if (arg->flags & FUSE_BIG_WRITES) 894 fc->big_writes = 1; 895 if (arg->flags & FUSE_DONT_MASK) 896 fc->dont_mask = 1; 897 if (arg->flags & FUSE_AUTO_INVAL_DATA) 898 fc->auto_inval_data = 1; 899 if (arg->flags & FUSE_DO_READDIRPLUS) { 900 fc->do_readdirplus = 1; 901 if (arg->flags & FUSE_READDIRPLUS_AUTO) 902 fc->readdirplus_auto = 1; 903 } 904 if (arg->flags & FUSE_ASYNC_DIO) 905 fc->async_dio = 1; 906 if (arg->flags & FUSE_WRITEBACK_CACHE) 907 fc->writeback_cache = 1; 908 if (arg->time_gran && arg->time_gran <= 1000000000) 909 fc->sb->s_time_gran = arg->time_gran; 910 } else { 911 ra_pages = fc->max_read / PAGE_CACHE_SIZE; 912 fc->no_lock = 1; 913 fc->no_flock = 1; 914 } 915 916 fc->bdi.ra_pages = min(fc->bdi.ra_pages, ra_pages); 917 fc->minor = arg->minor; 918 fc->max_write = arg->minor < 5 ? 4096 : arg->max_write; 919 fc->max_write = max_t(unsigned, 4096, fc->max_write); 920 fc->conn_init = 1; 921 } 922 fc->initialized = 1; 923 wake_up_all(&fc->blocked_waitq); 924 } 925 926 static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req) 927 { 928 struct fuse_init_in *arg = &req->misc.init_in; 929 930 arg->major = FUSE_KERNEL_VERSION; 931 arg->minor = FUSE_KERNEL_MINOR_VERSION; 932 arg->max_readahead = fc->bdi.ra_pages * PAGE_CACHE_SIZE; 933 arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC | 934 FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK | 935 FUSE_SPLICE_WRITE | FUSE_SPLICE_MOVE | FUSE_SPLICE_READ | 936 FUSE_FLOCK_LOCKS | FUSE_IOCTL_DIR | FUSE_AUTO_INVAL_DATA | 937 FUSE_DO_READDIRPLUS | FUSE_READDIRPLUS_AUTO | FUSE_ASYNC_DIO | 938 FUSE_WRITEBACK_CACHE | FUSE_NO_OPEN_SUPPORT; 939 req->in.h.opcode = FUSE_INIT; 940 req->in.numargs = 1; 941 req->in.args[0].size = sizeof(*arg); 942 req->in.args[0].value = arg; 943 req->out.numargs = 1; 944 /* Variable length argument used for backward compatibility 945 with interface version < 7.5. Rest of init_out is zeroed 946 by do_get_request(), so a short reply is not a problem */ 947 req->out.argvar = 1; 948 req->out.args[0].size = sizeof(struct fuse_init_out); 949 req->out.args[0].value = &req->misc.init_out; 950 req->end = process_init_reply; 951 fuse_request_send_background(fc, req); 952 } 953 954 static void fuse_free_conn(struct fuse_conn *fc) 955 { 956 kfree_rcu(fc, rcu); 957 } 958 959 static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb) 960 { 961 int err; 962 963 fc->bdi.name = "fuse"; 964 fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE; 965 /* fuse does it's own writeback accounting */ 966 fc->bdi.capabilities = BDI_CAP_NO_ACCT_WB | BDI_CAP_STRICTLIMIT; 967 968 err = bdi_init(&fc->bdi); 969 if (err) 970 return err; 971 972 fc->bdi_initialized = 1; 973 974 if (sb->s_bdev) { 975 err = bdi_register(&fc->bdi, NULL, "%u:%u-fuseblk", 976 MAJOR(fc->dev), MINOR(fc->dev)); 977 } else { 978 err = bdi_register_dev(&fc->bdi, fc->dev); 979 } 980 981 if (err) 982 return err; 983 984 /* 985 * For a single fuse filesystem use max 1% of dirty + 986 * writeback threshold. 987 * 988 * This gives about 1M of write buffer for memory maps on a 989 * machine with 1G and 10% dirty_ratio, which should be more 990 * than enough. 991 * 992 * Privileged users can raise it by writing to 993 * 994 * /sys/class/bdi/<bdi>/max_ratio 995 */ 996 bdi_set_max_ratio(&fc->bdi, 1); 997 998 return 0; 999 } 1000 1001 static int fuse_fill_super(struct super_block *sb, void *data, int silent) 1002 { 1003 struct fuse_conn *fc; 1004 struct inode *root; 1005 struct fuse_mount_data d; 1006 struct file *file; 1007 struct dentry *root_dentry; 1008 struct fuse_req *init_req; 1009 int err; 1010 int is_bdev = sb->s_bdev != NULL; 1011 1012 err = -EINVAL; 1013 if (sb->s_flags & MS_MANDLOCK) 1014 goto err; 1015 1016 sb->s_flags &= ~(MS_NOSEC | MS_I_VERSION); 1017 1018 if (!parse_fuse_opt(data, &d, is_bdev)) 1019 goto err; 1020 1021 if (is_bdev) { 1022 #ifdef CONFIG_BLOCK 1023 err = -EINVAL; 1024 if (!sb_set_blocksize(sb, d.blksize)) 1025 goto err; 1026 #endif 1027 } else { 1028 sb->s_blocksize = PAGE_CACHE_SIZE; 1029 sb->s_blocksize_bits = PAGE_CACHE_SHIFT; 1030 } 1031 sb->s_magic = FUSE_SUPER_MAGIC; 1032 sb->s_op = &fuse_super_operations; 1033 sb->s_maxbytes = MAX_LFS_FILESIZE; 1034 sb->s_time_gran = 1; 1035 sb->s_export_op = &fuse_export_operations; 1036 1037 file = fget(d.fd); 1038 err = -EINVAL; 1039 if (!file) 1040 goto err; 1041 1042 if ((file->f_op != &fuse_dev_operations) || 1043 (file->f_cred->user_ns != &init_user_ns)) 1044 goto err_fput; 1045 1046 fc = kmalloc(sizeof(*fc), GFP_KERNEL); 1047 err = -ENOMEM; 1048 if (!fc) 1049 goto err_fput; 1050 1051 fuse_conn_init(fc); 1052 1053 fc->dev = sb->s_dev; 1054 fc->sb = sb; 1055 err = fuse_bdi_init(fc, sb); 1056 if (err) 1057 goto err_put_conn; 1058 1059 sb->s_bdi = &fc->bdi; 1060 1061 /* Handle umasking inside the fuse code */ 1062 if (sb->s_flags & MS_POSIXACL) 1063 fc->dont_mask = 1; 1064 sb->s_flags |= MS_POSIXACL; 1065 1066 fc->release = fuse_free_conn; 1067 fc->flags = d.flags; 1068 fc->user_id = d.user_id; 1069 fc->group_id = d.group_id; 1070 fc->max_read = max_t(unsigned, 4096, d.max_read); 1071 1072 /* Used by get_root_inode() */ 1073 sb->s_fs_info = fc; 1074 1075 err = -ENOMEM; 1076 root = fuse_get_root_inode(sb, d.rootmode); 1077 root_dentry = d_make_root(root); 1078 if (!root_dentry) 1079 goto err_put_conn; 1080 /* only now - we want root dentry with NULL ->d_op */ 1081 sb->s_d_op = &fuse_dentry_operations; 1082 1083 init_req = fuse_request_alloc(0); 1084 if (!init_req) 1085 goto err_put_root; 1086 init_req->background = 1; 1087 1088 if (is_bdev) { 1089 fc->destroy_req = fuse_request_alloc(0); 1090 if (!fc->destroy_req) 1091 goto err_free_init_req; 1092 } 1093 1094 mutex_lock(&fuse_mutex); 1095 err = -EINVAL; 1096 if (file->private_data) 1097 goto err_unlock; 1098 1099 err = fuse_ctl_add_conn(fc); 1100 if (err) 1101 goto err_unlock; 1102 1103 list_add_tail(&fc->entry, &fuse_conn_list); 1104 sb->s_root = root_dentry; 1105 fc->connected = 1; 1106 file->private_data = fuse_conn_get(fc); 1107 mutex_unlock(&fuse_mutex); 1108 /* 1109 * atomic_dec_and_test() in fput() provides the necessary 1110 * memory barrier for file->private_data to be visible on all 1111 * CPUs after this 1112 */ 1113 fput(file); 1114 1115 fuse_send_init(fc, init_req); 1116 1117 return 0; 1118 1119 err_unlock: 1120 mutex_unlock(&fuse_mutex); 1121 err_free_init_req: 1122 fuse_request_free(init_req); 1123 err_put_root: 1124 dput(root_dentry); 1125 err_put_conn: 1126 fuse_bdi_destroy(fc); 1127 fuse_conn_put(fc); 1128 err_fput: 1129 fput(file); 1130 err: 1131 return err; 1132 } 1133 1134 static struct dentry *fuse_mount(struct file_system_type *fs_type, 1135 int flags, const char *dev_name, 1136 void *raw_data) 1137 { 1138 return mount_nodev(fs_type, flags, raw_data, fuse_fill_super); 1139 } 1140 1141 static void fuse_kill_sb_anon(struct super_block *sb) 1142 { 1143 struct fuse_conn *fc = get_fuse_conn_super(sb); 1144 1145 if (fc) { 1146 down_write(&fc->killsb); 1147 fc->sb = NULL; 1148 up_write(&fc->killsb); 1149 } 1150 1151 kill_anon_super(sb); 1152 } 1153 1154 static struct file_system_type fuse_fs_type = { 1155 .owner = THIS_MODULE, 1156 .name = "fuse", 1157 .fs_flags = FS_HAS_SUBTYPE, 1158 .mount = fuse_mount, 1159 .kill_sb = fuse_kill_sb_anon, 1160 }; 1161 MODULE_ALIAS_FS("fuse"); 1162 1163 #ifdef CONFIG_BLOCK 1164 static struct dentry *fuse_mount_blk(struct file_system_type *fs_type, 1165 int flags, const char *dev_name, 1166 void *raw_data) 1167 { 1168 return mount_bdev(fs_type, flags, dev_name, raw_data, fuse_fill_super); 1169 } 1170 1171 static void fuse_kill_sb_blk(struct super_block *sb) 1172 { 1173 struct fuse_conn *fc = get_fuse_conn_super(sb); 1174 1175 if (fc) { 1176 down_write(&fc->killsb); 1177 fc->sb = NULL; 1178 up_write(&fc->killsb); 1179 } 1180 1181 kill_block_super(sb); 1182 } 1183 1184 static struct file_system_type fuseblk_fs_type = { 1185 .owner = THIS_MODULE, 1186 .name = "fuseblk", 1187 .mount = fuse_mount_blk, 1188 .kill_sb = fuse_kill_sb_blk, 1189 .fs_flags = FS_REQUIRES_DEV | FS_HAS_SUBTYPE, 1190 }; 1191 MODULE_ALIAS_FS("fuseblk"); 1192 1193 static inline int register_fuseblk(void) 1194 { 1195 return register_filesystem(&fuseblk_fs_type); 1196 } 1197 1198 static inline void unregister_fuseblk(void) 1199 { 1200 unregister_filesystem(&fuseblk_fs_type); 1201 } 1202 #else 1203 static inline int register_fuseblk(void) 1204 { 1205 return 0; 1206 } 1207 1208 static inline void unregister_fuseblk(void) 1209 { 1210 } 1211 #endif 1212 1213 static void fuse_inode_init_once(void *foo) 1214 { 1215 struct inode *inode = foo; 1216 1217 inode_init_once(inode); 1218 } 1219 1220 static int __init fuse_fs_init(void) 1221 { 1222 int err; 1223 1224 fuse_inode_cachep = kmem_cache_create("fuse_inode", 1225 sizeof(struct fuse_inode), 1226 0, SLAB_HWCACHE_ALIGN, 1227 fuse_inode_init_once); 1228 err = -ENOMEM; 1229 if (!fuse_inode_cachep) 1230 goto out; 1231 1232 err = register_fuseblk(); 1233 if (err) 1234 goto out2; 1235 1236 err = register_filesystem(&fuse_fs_type); 1237 if (err) 1238 goto out3; 1239 1240 return 0; 1241 1242 out3: 1243 unregister_fuseblk(); 1244 out2: 1245 kmem_cache_destroy(fuse_inode_cachep); 1246 out: 1247 return err; 1248 } 1249 1250 static void fuse_fs_cleanup(void) 1251 { 1252 unregister_filesystem(&fuse_fs_type); 1253 unregister_fuseblk(); 1254 1255 /* 1256 * Make sure all delayed rcu free inodes are flushed before we 1257 * destroy cache. 1258 */ 1259 rcu_barrier(); 1260 kmem_cache_destroy(fuse_inode_cachep); 1261 } 1262 1263 static struct kobject *fuse_kobj; 1264 static struct kobject *connections_kobj; 1265 1266 static int fuse_sysfs_init(void) 1267 { 1268 int err; 1269 1270 fuse_kobj = kobject_create_and_add("fuse", fs_kobj); 1271 if (!fuse_kobj) { 1272 err = -ENOMEM; 1273 goto out_err; 1274 } 1275 1276 connections_kobj = kobject_create_and_add("connections", fuse_kobj); 1277 if (!connections_kobj) { 1278 err = -ENOMEM; 1279 goto out_fuse_unregister; 1280 } 1281 1282 return 0; 1283 1284 out_fuse_unregister: 1285 kobject_put(fuse_kobj); 1286 out_err: 1287 return err; 1288 } 1289 1290 static void fuse_sysfs_cleanup(void) 1291 { 1292 kobject_put(connections_kobj); 1293 kobject_put(fuse_kobj); 1294 } 1295 1296 static int __init fuse_init(void) 1297 { 1298 int res; 1299 1300 printk(KERN_INFO "fuse init (API version %i.%i)\n", 1301 FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION); 1302 1303 INIT_LIST_HEAD(&fuse_conn_list); 1304 res = fuse_fs_init(); 1305 if (res) 1306 goto err; 1307 1308 res = fuse_dev_init(); 1309 if (res) 1310 goto err_fs_cleanup; 1311 1312 res = fuse_sysfs_init(); 1313 if (res) 1314 goto err_dev_cleanup; 1315 1316 res = fuse_ctl_init(); 1317 if (res) 1318 goto err_sysfs_cleanup; 1319 1320 sanitize_global_limit(&max_user_bgreq); 1321 sanitize_global_limit(&max_user_congthresh); 1322 1323 return 0; 1324 1325 err_sysfs_cleanup: 1326 fuse_sysfs_cleanup(); 1327 err_dev_cleanup: 1328 fuse_dev_cleanup(); 1329 err_fs_cleanup: 1330 fuse_fs_cleanup(); 1331 err: 1332 return res; 1333 } 1334 1335 static void __exit fuse_exit(void) 1336 { 1337 printk(KERN_DEBUG "fuse exit\n"); 1338 1339 fuse_ctl_cleanup(); 1340 fuse_sysfs_cleanup(); 1341 fuse_fs_cleanup(); 1342 fuse_dev_cleanup(); 1343 } 1344 1345 module_init(fuse_init); 1346 module_exit(fuse_exit); 1347