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