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 static struct inode *fuse_alloc_inode(struct super_block *sb) 75 { 76 struct inode *inode; 77 struct fuse_inode *fi; 78 79 inode = kmem_cache_alloc(fuse_inode_cachep, GFP_KERNEL); 80 if (!inode) 81 return NULL; 82 83 fi = get_fuse_inode(inode); 84 fi->i_time = 0; 85 fi->nodeid = 0; 86 fi->nlookup = 0; 87 fi->attr_version = 0; 88 fi->writectr = 0; 89 INIT_LIST_HEAD(&fi->write_files); 90 INIT_LIST_HEAD(&fi->queued_writes); 91 INIT_LIST_HEAD(&fi->writepages); 92 init_waitqueue_head(&fi->page_waitq); 93 fi->forget_req = fuse_request_alloc(); 94 if (!fi->forget_req) { 95 kmem_cache_free(fuse_inode_cachep, inode); 96 return NULL; 97 } 98 99 return inode; 100 } 101 102 static void fuse_destroy_inode(struct inode *inode) 103 { 104 struct fuse_inode *fi = get_fuse_inode(inode); 105 BUG_ON(!list_empty(&fi->write_files)); 106 BUG_ON(!list_empty(&fi->queued_writes)); 107 if (fi->forget_req) 108 fuse_request_free(fi->forget_req); 109 kmem_cache_free(fuse_inode_cachep, inode); 110 } 111 112 void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req, 113 u64 nodeid, u64 nlookup) 114 { 115 struct fuse_forget_in *inarg = &req->misc.forget_in; 116 inarg->nlookup = nlookup; 117 req->in.h.opcode = FUSE_FORGET; 118 req->in.h.nodeid = nodeid; 119 req->in.numargs = 1; 120 req->in.args[0].size = sizeof(struct fuse_forget_in); 121 req->in.args[0].value = inarg; 122 fuse_request_send_noreply(fc, req); 123 } 124 125 static void fuse_clear_inode(struct inode *inode) 126 { 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_send_forget(fc, fi->forget_req, fi->nodeid, fi->nlookup); 131 fi->forget_req = 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 void fuse_truncate(struct address_space *mapping, loff_t offset) 144 { 145 /* See vmtruncate() */ 146 unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1); 147 truncate_inode_pages(mapping, offset); 148 unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1); 149 } 150 151 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr, 152 u64 attr_valid) 153 { 154 struct fuse_conn *fc = get_fuse_conn(inode); 155 struct fuse_inode *fi = get_fuse_inode(inode); 156 157 fi->attr_version = ++fc->attr_version; 158 fi->i_time = attr_valid; 159 160 inode->i_ino = attr->ino; 161 inode->i_mode = (inode->i_mode & S_IFMT) | (attr->mode & 07777); 162 inode->i_nlink = attr->nlink; 163 inode->i_uid = attr->uid; 164 inode->i_gid = attr->gid; 165 inode->i_blocks = attr->blocks; 166 inode->i_atime.tv_sec = attr->atime; 167 inode->i_atime.tv_nsec = attr->atimensec; 168 inode->i_mtime.tv_sec = attr->mtime; 169 inode->i_mtime.tv_nsec = attr->mtimensec; 170 inode->i_ctime.tv_sec = attr->ctime; 171 inode->i_ctime.tv_nsec = attr->ctimensec; 172 173 if (attr->blksize != 0) 174 inode->i_blkbits = ilog2(attr->blksize); 175 else 176 inode->i_blkbits = inode->i_sb->s_blocksize_bits; 177 178 /* 179 * Don't set the sticky bit in i_mode, unless we want the VFS 180 * to check permissions. This prevents failures due to the 181 * check in may_delete(). 182 */ 183 fi->orig_i_mode = inode->i_mode; 184 if (!(fc->flags & FUSE_DEFAULT_PERMISSIONS)) 185 inode->i_mode &= ~S_ISVTX; 186 } 187 188 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr, 189 u64 attr_valid, u64 attr_version) 190 { 191 struct fuse_conn *fc = get_fuse_conn(inode); 192 struct fuse_inode *fi = get_fuse_inode(inode); 193 loff_t oldsize; 194 195 spin_lock(&fc->lock); 196 if (attr_version != 0 && fi->attr_version > attr_version) { 197 spin_unlock(&fc->lock); 198 return; 199 } 200 201 fuse_change_attributes_common(inode, attr, attr_valid); 202 203 oldsize = inode->i_size; 204 i_size_write(inode, attr->size); 205 spin_unlock(&fc->lock); 206 207 if (S_ISREG(inode->i_mode) && oldsize != attr->size) { 208 if (attr->size < oldsize) 209 fuse_truncate(inode->i_mapping, attr->size); 210 invalidate_inode_pages2(inode->i_mapping); 211 } 212 } 213 214 static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr) 215 { 216 inode->i_mode = attr->mode & S_IFMT; 217 inode->i_size = attr->size; 218 if (S_ISREG(inode->i_mode)) { 219 fuse_init_common(inode); 220 fuse_init_file_inode(inode); 221 } else if (S_ISDIR(inode->i_mode)) 222 fuse_init_dir(inode); 223 else if (S_ISLNK(inode->i_mode)) 224 fuse_init_symlink(inode); 225 else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) || 226 S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) { 227 fuse_init_common(inode); 228 init_special_inode(inode, inode->i_mode, 229 new_decode_dev(attr->rdev)); 230 } else 231 BUG(); 232 } 233 234 int fuse_inode_eq(struct inode *inode, void *_nodeidp) 235 { 236 u64 nodeid = *(u64 *) _nodeidp; 237 if (get_node_id(inode) == nodeid) 238 return 1; 239 else 240 return 0; 241 } 242 243 static int fuse_inode_set(struct inode *inode, void *_nodeidp) 244 { 245 u64 nodeid = *(u64 *) _nodeidp; 246 get_fuse_inode(inode)->nodeid = nodeid; 247 return 0; 248 } 249 250 struct inode *fuse_iget(struct super_block *sb, u64 nodeid, 251 int generation, struct fuse_attr *attr, 252 u64 attr_valid, u64 attr_version) 253 { 254 struct inode *inode; 255 struct fuse_inode *fi; 256 struct fuse_conn *fc = get_fuse_conn_super(sb); 257 258 retry: 259 inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid); 260 if (!inode) 261 return NULL; 262 263 if ((inode->i_state & I_NEW)) { 264 inode->i_flags |= S_NOATIME|S_NOCMTIME; 265 inode->i_generation = generation; 266 inode->i_data.backing_dev_info = &fc->bdi; 267 fuse_init_inode(inode, attr); 268 unlock_new_inode(inode); 269 } else if ((inode->i_mode ^ attr->mode) & S_IFMT) { 270 /* Inode has changed type, any I/O on the old should fail */ 271 make_bad_inode(inode); 272 iput(inode); 273 goto retry; 274 } 275 276 fi = get_fuse_inode(inode); 277 spin_lock(&fc->lock); 278 fi->nlookup++; 279 spin_unlock(&fc->lock); 280 fuse_change_attributes(inode, attr, attr_valid, attr_version); 281 282 return inode; 283 } 284 285 int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid, 286 loff_t offset, loff_t len) 287 { 288 struct inode *inode; 289 pgoff_t pg_start; 290 pgoff_t pg_end; 291 292 inode = ilookup5(sb, nodeid, fuse_inode_eq, &nodeid); 293 if (!inode) 294 return -ENOENT; 295 296 fuse_invalidate_attr(inode); 297 if (offset >= 0) { 298 pg_start = offset >> PAGE_CACHE_SHIFT; 299 if (len <= 0) 300 pg_end = -1; 301 else 302 pg_end = (offset + len - 1) >> PAGE_CACHE_SHIFT; 303 invalidate_inode_pages2_range(inode->i_mapping, 304 pg_start, pg_end); 305 } 306 iput(inode); 307 return 0; 308 } 309 310 static void fuse_umount_begin(struct super_block *sb) 311 { 312 fuse_abort_conn(get_fuse_conn_super(sb)); 313 } 314 315 static void fuse_send_destroy(struct fuse_conn *fc) 316 { 317 struct fuse_req *req = fc->destroy_req; 318 if (req && fc->conn_init) { 319 fc->destroy_req = NULL; 320 req->in.h.opcode = FUSE_DESTROY; 321 req->force = 1; 322 fuse_request_send(fc, req); 323 fuse_put_request(fc, req); 324 } 325 } 326 327 static void fuse_bdi_destroy(struct fuse_conn *fc) 328 { 329 if (fc->bdi_initialized) 330 bdi_destroy(&fc->bdi); 331 } 332 333 void fuse_conn_kill(struct fuse_conn *fc) 334 { 335 spin_lock(&fc->lock); 336 fc->connected = 0; 337 fc->blocked = 0; 338 spin_unlock(&fc->lock); 339 /* Flush all readers on this fs */ 340 kill_fasync(&fc->fasync, SIGIO, POLL_IN); 341 wake_up_all(&fc->waitq); 342 wake_up_all(&fc->blocked_waitq); 343 wake_up_all(&fc->reserved_req_waitq); 344 mutex_lock(&fuse_mutex); 345 list_del(&fc->entry); 346 fuse_ctl_remove_conn(fc); 347 mutex_unlock(&fuse_mutex); 348 fuse_bdi_destroy(fc); 349 } 350 EXPORT_SYMBOL_GPL(fuse_conn_kill); 351 352 static void fuse_put_super(struct super_block *sb) 353 { 354 struct fuse_conn *fc = get_fuse_conn_super(sb); 355 356 fuse_send_destroy(fc); 357 fuse_conn_kill(fc); 358 fuse_conn_put(fc); 359 } 360 361 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr) 362 { 363 stbuf->f_type = FUSE_SUPER_MAGIC; 364 stbuf->f_bsize = attr->bsize; 365 stbuf->f_frsize = attr->frsize; 366 stbuf->f_blocks = attr->blocks; 367 stbuf->f_bfree = attr->bfree; 368 stbuf->f_bavail = attr->bavail; 369 stbuf->f_files = attr->files; 370 stbuf->f_ffree = attr->ffree; 371 stbuf->f_namelen = attr->namelen; 372 /* fsid is left zero */ 373 } 374 375 static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf) 376 { 377 struct super_block *sb = dentry->d_sb; 378 struct fuse_conn *fc = get_fuse_conn_super(sb); 379 struct fuse_req *req; 380 struct fuse_statfs_out outarg; 381 int err; 382 383 if (!fuse_allow_task(fc, current)) { 384 buf->f_type = FUSE_SUPER_MAGIC; 385 return 0; 386 } 387 388 req = fuse_get_req(fc); 389 if (IS_ERR(req)) 390 return PTR_ERR(req); 391 392 memset(&outarg, 0, sizeof(outarg)); 393 req->in.numargs = 0; 394 req->in.h.opcode = FUSE_STATFS; 395 req->in.h.nodeid = get_node_id(dentry->d_inode); 396 req->out.numargs = 1; 397 req->out.args[0].size = 398 fc->minor < 4 ? FUSE_COMPAT_STATFS_SIZE : sizeof(outarg); 399 req->out.args[0].value = &outarg; 400 fuse_request_send(fc, req); 401 err = req->out.h.error; 402 if (!err) 403 convert_fuse_statfs(buf, &outarg.st); 404 fuse_put_request(fc, req); 405 return err; 406 } 407 408 enum { 409 OPT_FD, 410 OPT_ROOTMODE, 411 OPT_USER_ID, 412 OPT_GROUP_ID, 413 OPT_DEFAULT_PERMISSIONS, 414 OPT_ALLOW_OTHER, 415 OPT_MAX_READ, 416 OPT_BLKSIZE, 417 OPT_ERR 418 }; 419 420 static const match_table_t tokens = { 421 {OPT_FD, "fd=%u"}, 422 {OPT_ROOTMODE, "rootmode=%o"}, 423 {OPT_USER_ID, "user_id=%u"}, 424 {OPT_GROUP_ID, "group_id=%u"}, 425 {OPT_DEFAULT_PERMISSIONS, "default_permissions"}, 426 {OPT_ALLOW_OTHER, "allow_other"}, 427 {OPT_MAX_READ, "max_read=%u"}, 428 {OPT_BLKSIZE, "blksize=%u"}, 429 {OPT_ERR, NULL} 430 }; 431 432 static int parse_fuse_opt(char *opt, struct fuse_mount_data *d, int is_bdev) 433 { 434 char *p; 435 memset(d, 0, sizeof(struct fuse_mount_data)); 436 d->max_read = ~0; 437 d->blksize = FUSE_DEFAULT_BLKSIZE; 438 439 while ((p = strsep(&opt, ",")) != NULL) { 440 int token; 441 int value; 442 substring_t args[MAX_OPT_ARGS]; 443 if (!*p) 444 continue; 445 446 token = match_token(p, tokens, args); 447 switch (token) { 448 case OPT_FD: 449 if (match_int(&args[0], &value)) 450 return 0; 451 d->fd = value; 452 d->fd_present = 1; 453 break; 454 455 case OPT_ROOTMODE: 456 if (match_octal(&args[0], &value)) 457 return 0; 458 if (!fuse_valid_type(value)) 459 return 0; 460 d->rootmode = value; 461 d->rootmode_present = 1; 462 break; 463 464 case OPT_USER_ID: 465 if (match_int(&args[0], &value)) 466 return 0; 467 d->user_id = value; 468 d->user_id_present = 1; 469 break; 470 471 case OPT_GROUP_ID: 472 if (match_int(&args[0], &value)) 473 return 0; 474 d->group_id = value; 475 d->group_id_present = 1; 476 break; 477 478 case OPT_DEFAULT_PERMISSIONS: 479 d->flags |= FUSE_DEFAULT_PERMISSIONS; 480 break; 481 482 case OPT_ALLOW_OTHER: 483 d->flags |= FUSE_ALLOW_OTHER; 484 break; 485 486 case OPT_MAX_READ: 487 if (match_int(&args[0], &value)) 488 return 0; 489 d->max_read = value; 490 break; 491 492 case OPT_BLKSIZE: 493 if (!is_bdev || match_int(&args[0], &value)) 494 return 0; 495 d->blksize = value; 496 break; 497 498 default: 499 return 0; 500 } 501 } 502 503 if (!d->fd_present || !d->rootmode_present || 504 !d->user_id_present || !d->group_id_present) 505 return 0; 506 507 return 1; 508 } 509 510 static int fuse_show_options(struct seq_file *m, struct vfsmount *mnt) 511 { 512 struct fuse_conn *fc = get_fuse_conn_super(mnt->mnt_sb); 513 514 seq_printf(m, ",user_id=%u", fc->user_id); 515 seq_printf(m, ",group_id=%u", fc->group_id); 516 if (fc->flags & FUSE_DEFAULT_PERMISSIONS) 517 seq_puts(m, ",default_permissions"); 518 if (fc->flags & FUSE_ALLOW_OTHER) 519 seq_puts(m, ",allow_other"); 520 if (fc->max_read != ~0) 521 seq_printf(m, ",max_read=%u", fc->max_read); 522 if (mnt->mnt_sb->s_bdev && 523 mnt->mnt_sb->s_blocksize != FUSE_DEFAULT_BLKSIZE) 524 seq_printf(m, ",blksize=%lu", mnt->mnt_sb->s_blocksize); 525 return 0; 526 } 527 528 void fuse_conn_init(struct fuse_conn *fc) 529 { 530 memset(fc, 0, sizeof(*fc)); 531 spin_lock_init(&fc->lock); 532 mutex_init(&fc->inst_mutex); 533 init_rwsem(&fc->killsb); 534 atomic_set(&fc->count, 1); 535 init_waitqueue_head(&fc->waitq); 536 init_waitqueue_head(&fc->blocked_waitq); 537 init_waitqueue_head(&fc->reserved_req_waitq); 538 INIT_LIST_HEAD(&fc->pending); 539 INIT_LIST_HEAD(&fc->processing); 540 INIT_LIST_HEAD(&fc->io); 541 INIT_LIST_HEAD(&fc->interrupts); 542 INIT_LIST_HEAD(&fc->bg_queue); 543 INIT_LIST_HEAD(&fc->entry); 544 atomic_set(&fc->num_waiting, 0); 545 fc->max_background = FUSE_DEFAULT_MAX_BACKGROUND; 546 fc->congestion_threshold = FUSE_DEFAULT_CONGESTION_THRESHOLD; 547 fc->khctr = 0; 548 fc->polled_files = RB_ROOT; 549 fc->reqctr = 0; 550 fc->blocked = 1; 551 fc->attr_version = 1; 552 get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key)); 553 } 554 EXPORT_SYMBOL_GPL(fuse_conn_init); 555 556 void fuse_conn_put(struct fuse_conn *fc) 557 { 558 if (atomic_dec_and_test(&fc->count)) { 559 if (fc->destroy_req) 560 fuse_request_free(fc->destroy_req); 561 mutex_destroy(&fc->inst_mutex); 562 fc->release(fc); 563 } 564 } 565 EXPORT_SYMBOL_GPL(fuse_conn_put); 566 567 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc) 568 { 569 atomic_inc(&fc->count); 570 return fc; 571 } 572 EXPORT_SYMBOL_GPL(fuse_conn_get); 573 574 static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned mode) 575 { 576 struct fuse_attr attr; 577 memset(&attr, 0, sizeof(attr)); 578 579 attr.mode = mode; 580 attr.ino = FUSE_ROOT_ID; 581 attr.nlink = 1; 582 return fuse_iget(sb, 1, 0, &attr, 0, 0); 583 } 584 585 struct fuse_inode_handle { 586 u64 nodeid; 587 u32 generation; 588 }; 589 590 static struct dentry *fuse_get_dentry(struct super_block *sb, 591 struct fuse_inode_handle *handle) 592 { 593 struct fuse_conn *fc = get_fuse_conn_super(sb); 594 struct inode *inode; 595 struct dentry *entry; 596 int err = -ESTALE; 597 598 if (handle->nodeid == 0) 599 goto out_err; 600 601 inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid); 602 if (!inode) { 603 struct fuse_entry_out outarg; 604 struct qstr name; 605 606 if (!fc->export_support) 607 goto out_err; 608 609 name.len = 1; 610 name.name = "."; 611 err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg, 612 &inode); 613 if (err && err != -ENOENT) 614 goto out_err; 615 if (err || !inode) { 616 err = -ESTALE; 617 goto out_err; 618 } 619 err = -EIO; 620 if (get_node_id(inode) != handle->nodeid) 621 goto out_iput; 622 } 623 err = -ESTALE; 624 if (inode->i_generation != handle->generation) 625 goto out_iput; 626 627 entry = d_obtain_alias(inode); 628 if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID) { 629 entry->d_op = &fuse_dentry_operations; 630 fuse_invalidate_entry_cache(entry); 631 } 632 633 return entry; 634 635 out_iput: 636 iput(inode); 637 out_err: 638 return ERR_PTR(err); 639 } 640 641 static int fuse_encode_fh(struct dentry *dentry, u32 *fh, int *max_len, 642 int connectable) 643 { 644 struct inode *inode = dentry->d_inode; 645 bool encode_parent = connectable && !S_ISDIR(inode->i_mode); 646 int len = encode_parent ? 6 : 3; 647 u64 nodeid; 648 u32 generation; 649 650 if (*max_len < len) 651 return 255; 652 653 nodeid = get_fuse_inode(inode)->nodeid; 654 generation = inode->i_generation; 655 656 fh[0] = (u32)(nodeid >> 32); 657 fh[1] = (u32)(nodeid & 0xffffffff); 658 fh[2] = generation; 659 660 if (encode_parent) { 661 struct inode *parent; 662 663 spin_lock(&dentry->d_lock); 664 parent = dentry->d_parent->d_inode; 665 nodeid = get_fuse_inode(parent)->nodeid; 666 generation = parent->i_generation; 667 spin_unlock(&dentry->d_lock); 668 669 fh[3] = (u32)(nodeid >> 32); 670 fh[4] = (u32)(nodeid & 0xffffffff); 671 fh[5] = generation; 672 } 673 674 *max_len = len; 675 return encode_parent ? 0x82 : 0x81; 676 } 677 678 static struct dentry *fuse_fh_to_dentry(struct super_block *sb, 679 struct fid *fid, int fh_len, int fh_type) 680 { 681 struct fuse_inode_handle handle; 682 683 if ((fh_type != 0x81 && fh_type != 0x82) || fh_len < 3) 684 return NULL; 685 686 handle.nodeid = (u64) fid->raw[0] << 32; 687 handle.nodeid |= (u64) fid->raw[1]; 688 handle.generation = fid->raw[2]; 689 return fuse_get_dentry(sb, &handle); 690 } 691 692 static struct dentry *fuse_fh_to_parent(struct super_block *sb, 693 struct fid *fid, int fh_len, int fh_type) 694 { 695 struct fuse_inode_handle parent; 696 697 if (fh_type != 0x82 || fh_len < 6) 698 return NULL; 699 700 parent.nodeid = (u64) fid->raw[3] << 32; 701 parent.nodeid |= (u64) fid->raw[4]; 702 parent.generation = fid->raw[5]; 703 return fuse_get_dentry(sb, &parent); 704 } 705 706 static struct dentry *fuse_get_parent(struct dentry *child) 707 { 708 struct inode *child_inode = child->d_inode; 709 struct fuse_conn *fc = get_fuse_conn(child_inode); 710 struct inode *inode; 711 struct dentry *parent; 712 struct fuse_entry_out outarg; 713 struct qstr name; 714 int err; 715 716 if (!fc->export_support) 717 return ERR_PTR(-ESTALE); 718 719 name.len = 2; 720 name.name = ".."; 721 err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode), 722 &name, &outarg, &inode); 723 if (err) { 724 if (err == -ENOENT) 725 return ERR_PTR(-ESTALE); 726 return ERR_PTR(err); 727 } 728 729 parent = d_obtain_alias(inode); 730 if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID) { 731 parent->d_op = &fuse_dentry_operations; 732 fuse_invalidate_entry_cache(parent); 733 } 734 735 return parent; 736 } 737 738 static const struct export_operations fuse_export_operations = { 739 .fh_to_dentry = fuse_fh_to_dentry, 740 .fh_to_parent = fuse_fh_to_parent, 741 .encode_fh = fuse_encode_fh, 742 .get_parent = fuse_get_parent, 743 }; 744 745 static const struct super_operations fuse_super_operations = { 746 .alloc_inode = fuse_alloc_inode, 747 .destroy_inode = fuse_destroy_inode, 748 .clear_inode = fuse_clear_inode, 749 .drop_inode = generic_delete_inode, 750 .remount_fs = fuse_remount_fs, 751 .put_super = fuse_put_super, 752 .umount_begin = fuse_umount_begin, 753 .statfs = fuse_statfs, 754 .show_options = fuse_show_options, 755 }; 756 757 static void sanitize_global_limit(unsigned *limit) 758 { 759 if (*limit == 0) 760 *limit = ((num_physpages << PAGE_SHIFT) >> 13) / 761 sizeof(struct fuse_req); 762 763 if (*limit >= 1 << 16) 764 *limit = (1 << 16) - 1; 765 } 766 767 static int set_global_limit(const char *val, struct kernel_param *kp) 768 { 769 int rv; 770 771 rv = param_set_uint(val, kp); 772 if (rv) 773 return rv; 774 775 sanitize_global_limit((unsigned *)kp->arg); 776 777 return 0; 778 } 779 780 static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg) 781 { 782 int cap_sys_admin = capable(CAP_SYS_ADMIN); 783 784 if (arg->minor < 13) 785 return; 786 787 sanitize_global_limit(&max_user_bgreq); 788 sanitize_global_limit(&max_user_congthresh); 789 790 if (arg->max_background) { 791 fc->max_background = arg->max_background; 792 793 if (!cap_sys_admin && fc->max_background > max_user_bgreq) 794 fc->max_background = max_user_bgreq; 795 } 796 if (arg->congestion_threshold) { 797 fc->congestion_threshold = arg->congestion_threshold; 798 799 if (!cap_sys_admin && 800 fc->congestion_threshold > max_user_congthresh) 801 fc->congestion_threshold = max_user_congthresh; 802 } 803 } 804 805 static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req) 806 { 807 struct fuse_init_out *arg = &req->misc.init_out; 808 809 if (req->out.h.error || arg->major != FUSE_KERNEL_VERSION) 810 fc->conn_error = 1; 811 else { 812 unsigned long ra_pages; 813 814 process_init_limits(fc, arg); 815 816 if (arg->minor >= 6) { 817 ra_pages = arg->max_readahead / PAGE_CACHE_SIZE; 818 if (arg->flags & FUSE_ASYNC_READ) 819 fc->async_read = 1; 820 if (!(arg->flags & FUSE_POSIX_LOCKS)) 821 fc->no_lock = 1; 822 if (arg->flags & FUSE_ATOMIC_O_TRUNC) 823 fc->atomic_o_trunc = 1; 824 if (arg->minor >= 9) { 825 /* LOOKUP has dependency on proto version */ 826 if (arg->flags & FUSE_EXPORT_SUPPORT) 827 fc->export_support = 1; 828 } 829 if (arg->flags & FUSE_BIG_WRITES) 830 fc->big_writes = 1; 831 if (arg->flags & FUSE_DONT_MASK) 832 fc->dont_mask = 1; 833 } else { 834 ra_pages = fc->max_read / PAGE_CACHE_SIZE; 835 fc->no_lock = 1; 836 } 837 838 fc->bdi.ra_pages = min(fc->bdi.ra_pages, ra_pages); 839 fc->minor = arg->minor; 840 fc->max_write = arg->minor < 5 ? 4096 : arg->max_write; 841 fc->max_write = max_t(unsigned, 4096, fc->max_write); 842 fc->conn_init = 1; 843 } 844 fc->blocked = 0; 845 wake_up_all(&fc->blocked_waitq); 846 } 847 848 static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req) 849 { 850 struct fuse_init_in *arg = &req->misc.init_in; 851 852 arg->major = FUSE_KERNEL_VERSION; 853 arg->minor = FUSE_KERNEL_MINOR_VERSION; 854 arg->max_readahead = fc->bdi.ra_pages * PAGE_CACHE_SIZE; 855 arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC | 856 FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK; 857 req->in.h.opcode = FUSE_INIT; 858 req->in.numargs = 1; 859 req->in.args[0].size = sizeof(*arg); 860 req->in.args[0].value = arg; 861 req->out.numargs = 1; 862 /* Variable length arguement used for backward compatibility 863 with interface version < 7.5. Rest of init_out is zeroed 864 by do_get_request(), so a short reply is not a problem */ 865 req->out.argvar = 1; 866 req->out.args[0].size = sizeof(struct fuse_init_out); 867 req->out.args[0].value = &req->misc.init_out; 868 req->end = process_init_reply; 869 fuse_request_send_background(fc, req); 870 } 871 872 static void fuse_free_conn(struct fuse_conn *fc) 873 { 874 kfree(fc); 875 } 876 877 static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb) 878 { 879 int err; 880 881 fc->bdi.name = "fuse"; 882 fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE; 883 fc->bdi.unplug_io_fn = default_unplug_io_fn; 884 /* fuse does it's own writeback accounting */ 885 fc->bdi.capabilities = BDI_CAP_NO_ACCT_WB; 886 887 err = bdi_init(&fc->bdi); 888 if (err) 889 return err; 890 891 fc->bdi_initialized = 1; 892 893 if (sb->s_bdev) { 894 err = bdi_register(&fc->bdi, NULL, "%u:%u-fuseblk", 895 MAJOR(fc->dev), MINOR(fc->dev)); 896 } else { 897 err = bdi_register_dev(&fc->bdi, fc->dev); 898 } 899 900 if (err) 901 return err; 902 903 /* 904 * For a single fuse filesystem use max 1% of dirty + 905 * writeback threshold. 906 * 907 * This gives about 1M of write buffer for memory maps on a 908 * machine with 1G and 10% dirty_ratio, which should be more 909 * than enough. 910 * 911 * Privileged users can raise it by writing to 912 * 913 * /sys/class/bdi/<bdi>/max_ratio 914 */ 915 bdi_set_max_ratio(&fc->bdi, 1); 916 917 return 0; 918 } 919 920 static int fuse_fill_super(struct super_block *sb, void *data, int silent) 921 { 922 struct fuse_conn *fc; 923 struct inode *root; 924 struct fuse_mount_data d; 925 struct file *file; 926 struct dentry *root_dentry; 927 struct fuse_req *init_req; 928 int err; 929 int is_bdev = sb->s_bdev != NULL; 930 931 err = -EINVAL; 932 if (sb->s_flags & MS_MANDLOCK) 933 goto err; 934 935 if (!parse_fuse_opt((char *) data, &d, is_bdev)) 936 goto err; 937 938 if (is_bdev) { 939 #ifdef CONFIG_BLOCK 940 err = -EINVAL; 941 if (!sb_set_blocksize(sb, d.blksize)) 942 goto err; 943 #endif 944 } else { 945 sb->s_blocksize = PAGE_CACHE_SIZE; 946 sb->s_blocksize_bits = PAGE_CACHE_SHIFT; 947 } 948 sb->s_magic = FUSE_SUPER_MAGIC; 949 sb->s_op = &fuse_super_operations; 950 sb->s_maxbytes = MAX_LFS_FILESIZE; 951 sb->s_export_op = &fuse_export_operations; 952 953 file = fget(d.fd); 954 err = -EINVAL; 955 if (!file) 956 goto err; 957 958 if (file->f_op != &fuse_dev_operations) 959 goto err_fput; 960 961 fc = kmalloc(sizeof(*fc), GFP_KERNEL); 962 err = -ENOMEM; 963 if (!fc) 964 goto err_fput; 965 966 fuse_conn_init(fc); 967 968 fc->dev = sb->s_dev; 969 fc->sb = sb; 970 err = fuse_bdi_init(fc, sb); 971 if (err) 972 goto err_put_conn; 973 974 sb->s_bdi = &fc->bdi; 975 976 /* Handle umasking inside the fuse code */ 977 if (sb->s_flags & MS_POSIXACL) 978 fc->dont_mask = 1; 979 sb->s_flags |= MS_POSIXACL; 980 981 fc->release = fuse_free_conn; 982 fc->flags = d.flags; 983 fc->user_id = d.user_id; 984 fc->group_id = d.group_id; 985 fc->max_read = max_t(unsigned, 4096, d.max_read); 986 987 /* Used by get_root_inode() */ 988 sb->s_fs_info = fc; 989 990 err = -ENOMEM; 991 root = fuse_get_root_inode(sb, d.rootmode); 992 if (!root) 993 goto err_put_conn; 994 995 root_dentry = d_alloc_root(root); 996 if (!root_dentry) { 997 iput(root); 998 goto err_put_conn; 999 } 1000 1001 init_req = fuse_request_alloc(); 1002 if (!init_req) 1003 goto err_put_root; 1004 1005 if (is_bdev) { 1006 fc->destroy_req = fuse_request_alloc(); 1007 if (!fc->destroy_req) 1008 goto err_free_init_req; 1009 } 1010 1011 mutex_lock(&fuse_mutex); 1012 err = -EINVAL; 1013 if (file->private_data) 1014 goto err_unlock; 1015 1016 err = fuse_ctl_add_conn(fc); 1017 if (err) 1018 goto err_unlock; 1019 1020 list_add_tail(&fc->entry, &fuse_conn_list); 1021 sb->s_root = root_dentry; 1022 fc->connected = 1; 1023 file->private_data = fuse_conn_get(fc); 1024 mutex_unlock(&fuse_mutex); 1025 /* 1026 * atomic_dec_and_test() in fput() provides the necessary 1027 * memory barrier for file->private_data to be visible on all 1028 * CPUs after this 1029 */ 1030 fput(file); 1031 1032 fuse_send_init(fc, init_req); 1033 1034 return 0; 1035 1036 err_unlock: 1037 mutex_unlock(&fuse_mutex); 1038 err_free_init_req: 1039 fuse_request_free(init_req); 1040 err_put_root: 1041 dput(root_dentry); 1042 err_put_conn: 1043 fuse_bdi_destroy(fc); 1044 fuse_conn_put(fc); 1045 err_fput: 1046 fput(file); 1047 err: 1048 return err; 1049 } 1050 1051 static int fuse_get_sb(struct file_system_type *fs_type, 1052 int flags, const char *dev_name, 1053 void *raw_data, struct vfsmount *mnt) 1054 { 1055 return get_sb_nodev(fs_type, flags, raw_data, fuse_fill_super, mnt); 1056 } 1057 1058 static void fuse_kill_sb_anon(struct super_block *sb) 1059 { 1060 struct fuse_conn *fc = get_fuse_conn_super(sb); 1061 1062 if (fc) { 1063 down_write(&fc->killsb); 1064 fc->sb = NULL; 1065 up_write(&fc->killsb); 1066 } 1067 1068 kill_anon_super(sb); 1069 } 1070 1071 static struct file_system_type fuse_fs_type = { 1072 .owner = THIS_MODULE, 1073 .name = "fuse", 1074 .fs_flags = FS_HAS_SUBTYPE, 1075 .get_sb = fuse_get_sb, 1076 .kill_sb = fuse_kill_sb_anon, 1077 }; 1078 1079 #ifdef CONFIG_BLOCK 1080 static int fuse_get_sb_blk(struct file_system_type *fs_type, 1081 int flags, const char *dev_name, 1082 void *raw_data, struct vfsmount *mnt) 1083 { 1084 return get_sb_bdev(fs_type, flags, dev_name, raw_data, fuse_fill_super, 1085 mnt); 1086 } 1087 1088 static void fuse_kill_sb_blk(struct super_block *sb) 1089 { 1090 struct fuse_conn *fc = get_fuse_conn_super(sb); 1091 1092 if (fc) { 1093 down_write(&fc->killsb); 1094 fc->sb = NULL; 1095 up_write(&fc->killsb); 1096 } 1097 1098 kill_block_super(sb); 1099 } 1100 1101 static struct file_system_type fuseblk_fs_type = { 1102 .owner = THIS_MODULE, 1103 .name = "fuseblk", 1104 .get_sb = fuse_get_sb_blk, 1105 .kill_sb = fuse_kill_sb_blk, 1106 .fs_flags = FS_REQUIRES_DEV | FS_HAS_SUBTYPE, 1107 }; 1108 1109 static inline int register_fuseblk(void) 1110 { 1111 return register_filesystem(&fuseblk_fs_type); 1112 } 1113 1114 static inline void unregister_fuseblk(void) 1115 { 1116 unregister_filesystem(&fuseblk_fs_type); 1117 } 1118 #else 1119 static inline int register_fuseblk(void) 1120 { 1121 return 0; 1122 } 1123 1124 static inline void unregister_fuseblk(void) 1125 { 1126 } 1127 #endif 1128 1129 static void fuse_inode_init_once(void *foo) 1130 { 1131 struct inode *inode = foo; 1132 1133 inode_init_once(inode); 1134 } 1135 1136 static int __init fuse_fs_init(void) 1137 { 1138 int err; 1139 1140 err = register_filesystem(&fuse_fs_type); 1141 if (err) 1142 goto out; 1143 1144 err = register_fuseblk(); 1145 if (err) 1146 goto out_unreg; 1147 1148 fuse_inode_cachep = kmem_cache_create("fuse_inode", 1149 sizeof(struct fuse_inode), 1150 0, SLAB_HWCACHE_ALIGN, 1151 fuse_inode_init_once); 1152 err = -ENOMEM; 1153 if (!fuse_inode_cachep) 1154 goto out_unreg2; 1155 1156 return 0; 1157 1158 out_unreg2: 1159 unregister_fuseblk(); 1160 out_unreg: 1161 unregister_filesystem(&fuse_fs_type); 1162 out: 1163 return err; 1164 } 1165 1166 static void fuse_fs_cleanup(void) 1167 { 1168 unregister_filesystem(&fuse_fs_type); 1169 unregister_fuseblk(); 1170 kmem_cache_destroy(fuse_inode_cachep); 1171 } 1172 1173 static struct kobject *fuse_kobj; 1174 static struct kobject *connections_kobj; 1175 1176 static int fuse_sysfs_init(void) 1177 { 1178 int err; 1179 1180 fuse_kobj = kobject_create_and_add("fuse", fs_kobj); 1181 if (!fuse_kobj) { 1182 err = -ENOMEM; 1183 goto out_err; 1184 } 1185 1186 connections_kobj = kobject_create_and_add("connections", fuse_kobj); 1187 if (!connections_kobj) { 1188 err = -ENOMEM; 1189 goto out_fuse_unregister; 1190 } 1191 1192 return 0; 1193 1194 out_fuse_unregister: 1195 kobject_put(fuse_kobj); 1196 out_err: 1197 return err; 1198 } 1199 1200 static void fuse_sysfs_cleanup(void) 1201 { 1202 kobject_put(connections_kobj); 1203 kobject_put(fuse_kobj); 1204 } 1205 1206 static int __init fuse_init(void) 1207 { 1208 int res; 1209 1210 printk(KERN_INFO "fuse init (API version %i.%i)\n", 1211 FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION); 1212 1213 INIT_LIST_HEAD(&fuse_conn_list); 1214 res = fuse_fs_init(); 1215 if (res) 1216 goto err; 1217 1218 res = fuse_dev_init(); 1219 if (res) 1220 goto err_fs_cleanup; 1221 1222 res = fuse_sysfs_init(); 1223 if (res) 1224 goto err_dev_cleanup; 1225 1226 res = fuse_ctl_init(); 1227 if (res) 1228 goto err_sysfs_cleanup; 1229 1230 sanitize_global_limit(&max_user_bgreq); 1231 sanitize_global_limit(&max_user_congthresh); 1232 1233 return 0; 1234 1235 err_sysfs_cleanup: 1236 fuse_sysfs_cleanup(); 1237 err_dev_cleanup: 1238 fuse_dev_cleanup(); 1239 err_fs_cleanup: 1240 fuse_fs_cleanup(); 1241 err: 1242 return res; 1243 } 1244 1245 static void __exit fuse_exit(void) 1246 { 1247 printk(KERN_DEBUG "fuse exit\n"); 1248 1249 fuse_ctl_cleanup(); 1250 fuse_sysfs_cleanup(); 1251 fuse_fs_cleanup(); 1252 fuse_dev_cleanup(); 1253 } 1254 1255 module_init(fuse_init); 1256 module_exit(fuse_exit); 1257