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