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