1 /* 2 FUSE: Filesystem in Userspace 3 Copyright (C) 2001-2006 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/parser.h> 18 #include <linux/statfs.h> 19 #include <linux/random.h> 20 21 MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>"); 22 MODULE_DESCRIPTION("Filesystem in Userspace"); 23 MODULE_LICENSE("GPL"); 24 25 static kmem_cache_t *fuse_inode_cachep; 26 struct list_head fuse_conn_list; 27 DEFINE_MUTEX(fuse_mutex); 28 29 #define FUSE_SUPER_MAGIC 0x65735546 30 31 struct fuse_mount_data { 32 int fd; 33 unsigned rootmode; 34 unsigned user_id; 35 unsigned group_id; 36 unsigned fd_present : 1; 37 unsigned rootmode_present : 1; 38 unsigned user_id_present : 1; 39 unsigned group_id_present : 1; 40 unsigned flags; 41 unsigned max_read; 42 }; 43 44 static struct inode *fuse_alloc_inode(struct super_block *sb) 45 { 46 struct inode *inode; 47 struct fuse_inode *fi; 48 49 inode = kmem_cache_alloc(fuse_inode_cachep, SLAB_KERNEL); 50 if (!inode) 51 return NULL; 52 53 fi = get_fuse_inode(inode); 54 fi->i_time = jiffies - 1; 55 fi->nodeid = 0; 56 fi->nlookup = 0; 57 fi->forget_req = fuse_request_alloc(); 58 if (!fi->forget_req) { 59 kmem_cache_free(fuse_inode_cachep, inode); 60 return NULL; 61 } 62 63 return inode; 64 } 65 66 static void fuse_destroy_inode(struct inode *inode) 67 { 68 struct fuse_inode *fi = get_fuse_inode(inode); 69 if (fi->forget_req) 70 fuse_request_free(fi->forget_req); 71 kmem_cache_free(fuse_inode_cachep, inode); 72 } 73 74 static void fuse_read_inode(struct inode *inode) 75 { 76 /* No op */ 77 } 78 79 void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req, 80 unsigned long nodeid, u64 nlookup) 81 { 82 struct fuse_forget_in *inarg = &req->misc.forget_in; 83 inarg->nlookup = nlookup; 84 req->in.h.opcode = FUSE_FORGET; 85 req->in.h.nodeid = nodeid; 86 req->in.numargs = 1; 87 req->in.args[0].size = sizeof(struct fuse_forget_in); 88 req->in.args[0].value = inarg; 89 request_send_noreply(fc, req); 90 } 91 92 static void fuse_clear_inode(struct inode *inode) 93 { 94 if (inode->i_sb->s_flags & MS_ACTIVE) { 95 struct fuse_conn *fc = get_fuse_conn(inode); 96 struct fuse_inode *fi = get_fuse_inode(inode); 97 fuse_send_forget(fc, fi->forget_req, fi->nodeid, fi->nlookup); 98 fi->forget_req = NULL; 99 } 100 } 101 102 static int fuse_remount_fs(struct super_block *sb, int *flags, char *data) 103 { 104 if (*flags & MS_MANDLOCK) 105 return -EINVAL; 106 107 return 0; 108 } 109 110 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr) 111 { 112 if (S_ISREG(inode->i_mode) && i_size_read(inode) != attr->size) 113 invalidate_inode_pages(inode->i_mapping); 114 115 inode->i_ino = attr->ino; 116 inode->i_mode = (inode->i_mode & S_IFMT) + (attr->mode & 07777); 117 inode->i_nlink = attr->nlink; 118 inode->i_uid = attr->uid; 119 inode->i_gid = attr->gid; 120 i_size_write(inode, attr->size); 121 inode->i_blksize = PAGE_CACHE_SIZE; 122 inode->i_blocks = attr->blocks; 123 inode->i_atime.tv_sec = attr->atime; 124 inode->i_atime.tv_nsec = attr->atimensec; 125 inode->i_mtime.tv_sec = attr->mtime; 126 inode->i_mtime.tv_nsec = attr->mtimensec; 127 inode->i_ctime.tv_sec = attr->ctime; 128 inode->i_ctime.tv_nsec = attr->ctimensec; 129 } 130 131 static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr) 132 { 133 inode->i_mode = attr->mode & S_IFMT; 134 i_size_write(inode, attr->size); 135 if (S_ISREG(inode->i_mode)) { 136 fuse_init_common(inode); 137 fuse_init_file_inode(inode); 138 } else if (S_ISDIR(inode->i_mode)) 139 fuse_init_dir(inode); 140 else if (S_ISLNK(inode->i_mode)) 141 fuse_init_symlink(inode); 142 else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) || 143 S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) { 144 fuse_init_common(inode); 145 init_special_inode(inode, inode->i_mode, 146 new_decode_dev(attr->rdev)); 147 } else 148 BUG(); 149 } 150 151 static int fuse_inode_eq(struct inode *inode, void *_nodeidp) 152 { 153 unsigned long nodeid = *(unsigned long *) _nodeidp; 154 if (get_node_id(inode) == nodeid) 155 return 1; 156 else 157 return 0; 158 } 159 160 static int fuse_inode_set(struct inode *inode, void *_nodeidp) 161 { 162 unsigned long nodeid = *(unsigned long *) _nodeidp; 163 get_fuse_inode(inode)->nodeid = nodeid; 164 return 0; 165 } 166 167 struct inode *fuse_iget(struct super_block *sb, unsigned long nodeid, 168 int generation, struct fuse_attr *attr) 169 { 170 struct inode *inode; 171 struct fuse_inode *fi; 172 struct fuse_conn *fc = get_fuse_conn_super(sb); 173 int retried = 0; 174 175 retry: 176 inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid); 177 if (!inode) 178 return NULL; 179 180 if ((inode->i_state & I_NEW)) { 181 inode->i_flags |= S_NOATIME|S_NOCMTIME; 182 inode->i_generation = generation; 183 inode->i_data.backing_dev_info = &fc->bdi; 184 fuse_init_inode(inode, attr); 185 unlock_new_inode(inode); 186 } else if ((inode->i_mode ^ attr->mode) & S_IFMT) { 187 BUG_ON(retried); 188 /* Inode has changed type, any I/O on the old should fail */ 189 make_bad_inode(inode); 190 iput(inode); 191 retried = 1; 192 goto retry; 193 } 194 195 fi = get_fuse_inode(inode); 196 fi->nlookup ++; 197 fuse_change_attributes(inode, attr); 198 return inode; 199 } 200 201 static void fuse_umount_begin(struct vfsmount *vfsmnt, int flags) 202 { 203 if (flags & MNT_FORCE) 204 fuse_abort_conn(get_fuse_conn_super(vfsmnt->mnt_sb)); 205 } 206 207 static void fuse_put_super(struct super_block *sb) 208 { 209 struct fuse_conn *fc = get_fuse_conn_super(sb); 210 211 spin_lock(&fc->lock); 212 fc->connected = 0; 213 fc->blocked = 0; 214 spin_unlock(&fc->lock); 215 /* Flush all readers on this fs */ 216 kill_fasync(&fc->fasync, SIGIO, POLL_IN); 217 wake_up_all(&fc->waitq); 218 wake_up_all(&fc->blocked_waitq); 219 mutex_lock(&fuse_mutex); 220 list_del(&fc->entry); 221 fuse_ctl_remove_conn(fc); 222 mutex_unlock(&fuse_mutex); 223 fuse_conn_put(fc); 224 } 225 226 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr) 227 { 228 stbuf->f_type = FUSE_SUPER_MAGIC; 229 stbuf->f_bsize = attr->bsize; 230 stbuf->f_frsize = attr->frsize; 231 stbuf->f_blocks = attr->blocks; 232 stbuf->f_bfree = attr->bfree; 233 stbuf->f_bavail = attr->bavail; 234 stbuf->f_files = attr->files; 235 stbuf->f_ffree = attr->ffree; 236 stbuf->f_namelen = attr->namelen; 237 /* fsid is left zero */ 238 } 239 240 static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf) 241 { 242 struct super_block *sb = dentry->d_sb; 243 struct fuse_conn *fc = get_fuse_conn_super(sb); 244 struct fuse_req *req; 245 struct fuse_statfs_out outarg; 246 int err; 247 248 req = fuse_get_req(fc); 249 if (IS_ERR(req)) 250 return PTR_ERR(req); 251 252 memset(&outarg, 0, sizeof(outarg)); 253 req->in.numargs = 0; 254 req->in.h.opcode = FUSE_STATFS; 255 req->out.numargs = 1; 256 req->out.args[0].size = 257 fc->minor < 4 ? FUSE_COMPAT_STATFS_SIZE : sizeof(outarg); 258 req->out.args[0].value = &outarg; 259 request_send(fc, req); 260 err = req->out.h.error; 261 if (!err) 262 convert_fuse_statfs(buf, &outarg.st); 263 fuse_put_request(fc, req); 264 return err; 265 } 266 267 enum { 268 OPT_FD, 269 OPT_ROOTMODE, 270 OPT_USER_ID, 271 OPT_GROUP_ID, 272 OPT_DEFAULT_PERMISSIONS, 273 OPT_ALLOW_OTHER, 274 OPT_MAX_READ, 275 OPT_ERR 276 }; 277 278 static match_table_t tokens = { 279 {OPT_FD, "fd=%u"}, 280 {OPT_ROOTMODE, "rootmode=%o"}, 281 {OPT_USER_ID, "user_id=%u"}, 282 {OPT_GROUP_ID, "group_id=%u"}, 283 {OPT_DEFAULT_PERMISSIONS, "default_permissions"}, 284 {OPT_ALLOW_OTHER, "allow_other"}, 285 {OPT_MAX_READ, "max_read=%u"}, 286 {OPT_ERR, NULL} 287 }; 288 289 static int parse_fuse_opt(char *opt, struct fuse_mount_data *d) 290 { 291 char *p; 292 memset(d, 0, sizeof(struct fuse_mount_data)); 293 d->max_read = ~0; 294 295 while ((p = strsep(&opt, ",")) != NULL) { 296 int token; 297 int value; 298 substring_t args[MAX_OPT_ARGS]; 299 if (!*p) 300 continue; 301 302 token = match_token(p, tokens, args); 303 switch (token) { 304 case OPT_FD: 305 if (match_int(&args[0], &value)) 306 return 0; 307 d->fd = value; 308 d->fd_present = 1; 309 break; 310 311 case OPT_ROOTMODE: 312 if (match_octal(&args[0], &value)) 313 return 0; 314 d->rootmode = value; 315 d->rootmode_present = 1; 316 break; 317 318 case OPT_USER_ID: 319 if (match_int(&args[0], &value)) 320 return 0; 321 d->user_id = value; 322 d->user_id_present = 1; 323 break; 324 325 case OPT_GROUP_ID: 326 if (match_int(&args[0], &value)) 327 return 0; 328 d->group_id = value; 329 d->group_id_present = 1; 330 break; 331 332 case OPT_DEFAULT_PERMISSIONS: 333 d->flags |= FUSE_DEFAULT_PERMISSIONS; 334 break; 335 336 case OPT_ALLOW_OTHER: 337 d->flags |= FUSE_ALLOW_OTHER; 338 break; 339 340 case OPT_MAX_READ: 341 if (match_int(&args[0], &value)) 342 return 0; 343 d->max_read = value; 344 break; 345 346 default: 347 return 0; 348 } 349 } 350 351 if (!d->fd_present || !d->rootmode_present || 352 !d->user_id_present || !d->group_id_present) 353 return 0; 354 355 return 1; 356 } 357 358 static int fuse_show_options(struct seq_file *m, struct vfsmount *mnt) 359 { 360 struct fuse_conn *fc = get_fuse_conn_super(mnt->mnt_sb); 361 362 seq_printf(m, ",user_id=%u", fc->user_id); 363 seq_printf(m, ",group_id=%u", fc->group_id); 364 if (fc->flags & FUSE_DEFAULT_PERMISSIONS) 365 seq_puts(m, ",default_permissions"); 366 if (fc->flags & FUSE_ALLOW_OTHER) 367 seq_puts(m, ",allow_other"); 368 if (fc->max_read != ~0) 369 seq_printf(m, ",max_read=%u", fc->max_read); 370 return 0; 371 } 372 373 static struct fuse_conn *new_conn(void) 374 { 375 struct fuse_conn *fc; 376 377 fc = kzalloc(sizeof(*fc), GFP_KERNEL); 378 if (fc) { 379 spin_lock_init(&fc->lock); 380 atomic_set(&fc->count, 1); 381 init_waitqueue_head(&fc->waitq); 382 init_waitqueue_head(&fc->blocked_waitq); 383 INIT_LIST_HEAD(&fc->pending); 384 INIT_LIST_HEAD(&fc->processing); 385 INIT_LIST_HEAD(&fc->io); 386 INIT_LIST_HEAD(&fc->interrupts); 387 atomic_set(&fc->num_waiting, 0); 388 fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE; 389 fc->bdi.unplug_io_fn = default_unplug_io_fn; 390 fc->reqctr = 0; 391 fc->blocked = 1; 392 get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key)); 393 } 394 return fc; 395 } 396 397 void fuse_conn_put(struct fuse_conn *fc) 398 { 399 if (atomic_dec_and_test(&fc->count)) 400 kfree(fc); 401 } 402 403 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc) 404 { 405 atomic_inc(&fc->count); 406 return fc; 407 } 408 409 static struct inode *get_root_inode(struct super_block *sb, unsigned mode) 410 { 411 struct fuse_attr attr; 412 memset(&attr, 0, sizeof(attr)); 413 414 attr.mode = mode; 415 attr.ino = FUSE_ROOT_ID; 416 return fuse_iget(sb, 1, 0, &attr); 417 } 418 419 static struct super_operations fuse_super_operations = { 420 .alloc_inode = fuse_alloc_inode, 421 .destroy_inode = fuse_destroy_inode, 422 .read_inode = fuse_read_inode, 423 .clear_inode = fuse_clear_inode, 424 .remount_fs = fuse_remount_fs, 425 .put_super = fuse_put_super, 426 .umount_begin = fuse_umount_begin, 427 .statfs = fuse_statfs, 428 .show_options = fuse_show_options, 429 }; 430 431 static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req) 432 { 433 struct fuse_init_out *arg = &req->misc.init_out; 434 435 if (req->out.h.error || arg->major != FUSE_KERNEL_VERSION) 436 fc->conn_error = 1; 437 else { 438 unsigned long ra_pages; 439 440 if (arg->minor >= 6) { 441 ra_pages = arg->max_readahead / PAGE_CACHE_SIZE; 442 if (arg->flags & FUSE_ASYNC_READ) 443 fc->async_read = 1; 444 if (!(arg->flags & FUSE_POSIX_LOCKS)) 445 fc->no_lock = 1; 446 } else { 447 ra_pages = fc->max_read / PAGE_CACHE_SIZE; 448 fc->no_lock = 1; 449 } 450 451 fc->bdi.ra_pages = min(fc->bdi.ra_pages, ra_pages); 452 fc->minor = arg->minor; 453 fc->max_write = arg->minor < 5 ? 4096 : arg->max_write; 454 } 455 fuse_put_request(fc, req); 456 fc->blocked = 0; 457 wake_up_all(&fc->blocked_waitq); 458 } 459 460 static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req) 461 { 462 struct fuse_init_in *arg = &req->misc.init_in; 463 464 arg->major = FUSE_KERNEL_VERSION; 465 arg->minor = FUSE_KERNEL_MINOR_VERSION; 466 arg->max_readahead = fc->bdi.ra_pages * PAGE_CACHE_SIZE; 467 arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS; 468 req->in.h.opcode = FUSE_INIT; 469 req->in.numargs = 1; 470 req->in.args[0].size = sizeof(*arg); 471 req->in.args[0].value = arg; 472 req->out.numargs = 1; 473 /* Variable length arguement used for backward compatibility 474 with interface version < 7.5. Rest of init_out is zeroed 475 by do_get_request(), so a short reply is not a problem */ 476 req->out.argvar = 1; 477 req->out.args[0].size = sizeof(struct fuse_init_out); 478 req->out.args[0].value = &req->misc.init_out; 479 req->end = process_init_reply; 480 request_send_background(fc, req); 481 } 482 483 static u64 conn_id(void) 484 { 485 static u64 ctr = 1; 486 return ctr++; 487 } 488 489 static int fuse_fill_super(struct super_block *sb, void *data, int silent) 490 { 491 struct fuse_conn *fc; 492 struct inode *root; 493 struct fuse_mount_data d; 494 struct file *file; 495 struct dentry *root_dentry; 496 struct fuse_req *init_req; 497 int err; 498 499 if (sb->s_flags & MS_MANDLOCK) 500 return -EINVAL; 501 502 if (!parse_fuse_opt((char *) data, &d)) 503 return -EINVAL; 504 505 sb->s_blocksize = PAGE_CACHE_SIZE; 506 sb->s_blocksize_bits = PAGE_CACHE_SHIFT; 507 sb->s_magic = FUSE_SUPER_MAGIC; 508 sb->s_op = &fuse_super_operations; 509 sb->s_maxbytes = MAX_LFS_FILESIZE; 510 511 file = fget(d.fd); 512 if (!file) 513 return -EINVAL; 514 515 if (file->f_op != &fuse_dev_operations) 516 return -EINVAL; 517 518 fc = new_conn(); 519 if (!fc) 520 return -ENOMEM; 521 522 fc->flags = d.flags; 523 fc->user_id = d.user_id; 524 fc->group_id = d.group_id; 525 fc->max_read = d.max_read; 526 527 /* Used by get_root_inode() */ 528 sb->s_fs_info = fc; 529 530 err = -ENOMEM; 531 root = get_root_inode(sb, d.rootmode); 532 if (!root) 533 goto err; 534 535 root_dentry = d_alloc_root(root); 536 if (!root_dentry) { 537 iput(root); 538 goto err; 539 } 540 541 init_req = fuse_request_alloc(); 542 if (!init_req) 543 goto err_put_root; 544 545 mutex_lock(&fuse_mutex); 546 err = -EINVAL; 547 if (file->private_data) 548 goto err_unlock; 549 550 fc->id = conn_id(); 551 err = fuse_ctl_add_conn(fc); 552 if (err) 553 goto err_unlock; 554 555 list_add_tail(&fc->entry, &fuse_conn_list); 556 sb->s_root = root_dentry; 557 fc->connected = 1; 558 file->private_data = fuse_conn_get(fc); 559 mutex_unlock(&fuse_mutex); 560 /* 561 * atomic_dec_and_test() in fput() provides the necessary 562 * memory barrier for file->private_data to be visible on all 563 * CPUs after this 564 */ 565 fput(file); 566 567 fuse_send_init(fc, init_req); 568 569 return 0; 570 571 err_unlock: 572 mutex_unlock(&fuse_mutex); 573 fuse_request_free(init_req); 574 err_put_root: 575 dput(root_dentry); 576 err: 577 fput(file); 578 fuse_conn_put(fc); 579 return err; 580 } 581 582 static int fuse_get_sb(struct file_system_type *fs_type, 583 int flags, const char *dev_name, 584 void *raw_data, struct vfsmount *mnt) 585 { 586 return get_sb_nodev(fs_type, flags, raw_data, fuse_fill_super, mnt); 587 } 588 589 static struct file_system_type fuse_fs_type = { 590 .owner = THIS_MODULE, 591 .name = "fuse", 592 .get_sb = fuse_get_sb, 593 .kill_sb = kill_anon_super, 594 }; 595 596 static decl_subsys(fuse, NULL, NULL); 597 static decl_subsys(connections, NULL, NULL); 598 599 static void fuse_inode_init_once(void *foo, kmem_cache_t *cachep, 600 unsigned long flags) 601 { 602 struct inode * inode = foo; 603 604 if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) == 605 SLAB_CTOR_CONSTRUCTOR) 606 inode_init_once(inode); 607 } 608 609 static int __init fuse_fs_init(void) 610 { 611 int err; 612 613 err = register_filesystem(&fuse_fs_type); 614 if (err) 615 printk("fuse: failed to register filesystem\n"); 616 else { 617 fuse_inode_cachep = kmem_cache_create("fuse_inode", 618 sizeof(struct fuse_inode), 619 0, SLAB_HWCACHE_ALIGN, 620 fuse_inode_init_once, NULL); 621 if (!fuse_inode_cachep) { 622 unregister_filesystem(&fuse_fs_type); 623 err = -ENOMEM; 624 } 625 } 626 627 return err; 628 } 629 630 static void fuse_fs_cleanup(void) 631 { 632 unregister_filesystem(&fuse_fs_type); 633 kmem_cache_destroy(fuse_inode_cachep); 634 } 635 636 static int fuse_sysfs_init(void) 637 { 638 int err; 639 640 kset_set_kset_s(&fuse_subsys, fs_subsys); 641 err = subsystem_register(&fuse_subsys); 642 if (err) 643 goto out_err; 644 645 kset_set_kset_s(&connections_subsys, fuse_subsys); 646 err = subsystem_register(&connections_subsys); 647 if (err) 648 goto out_fuse_unregister; 649 650 return 0; 651 652 out_fuse_unregister: 653 subsystem_unregister(&fuse_subsys); 654 out_err: 655 return err; 656 } 657 658 static void fuse_sysfs_cleanup(void) 659 { 660 subsystem_unregister(&connections_subsys); 661 subsystem_unregister(&fuse_subsys); 662 } 663 664 static int __init fuse_init(void) 665 { 666 int res; 667 668 printk("fuse init (API version %i.%i)\n", 669 FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION); 670 671 INIT_LIST_HEAD(&fuse_conn_list); 672 res = fuse_fs_init(); 673 if (res) 674 goto err; 675 676 res = fuse_dev_init(); 677 if (res) 678 goto err_fs_cleanup; 679 680 res = fuse_sysfs_init(); 681 if (res) 682 goto err_dev_cleanup; 683 684 res = fuse_ctl_init(); 685 if (res) 686 goto err_sysfs_cleanup; 687 688 return 0; 689 690 err_sysfs_cleanup: 691 fuse_sysfs_cleanup(); 692 err_dev_cleanup: 693 fuse_dev_cleanup(); 694 err_fs_cleanup: 695 fuse_fs_cleanup(); 696 err: 697 return res; 698 } 699 700 static void __exit fuse_exit(void) 701 { 702 printk(KERN_DEBUG "fuse exit\n"); 703 704 fuse_ctl_cleanup(); 705 fuse_sysfs_cleanup(); 706 fuse_fs_cleanup(); 707 fuse_dev_cleanup(); 708 } 709 710 module_init(fuse_init); 711 module_exit(fuse_exit); 712