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/parser.h> 18 #include <linux/statfs.h> 19 #include <linux/random.h> 20 #include <linux/sched.h> 21 #include <linux/exportfs.h> 22 #include <linux/smp_lock.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 #define FUSE_SUPER_MAGIC 0x65735546 33 34 #define FUSE_DEFAULT_BLKSIZE 512 35 36 struct fuse_mount_data { 37 int fd; 38 unsigned rootmode; 39 unsigned user_id; 40 unsigned group_id; 41 unsigned fd_present:1; 42 unsigned rootmode_present:1; 43 unsigned user_id_present:1; 44 unsigned group_id_present:1; 45 unsigned flags; 46 unsigned max_read; 47 unsigned blksize; 48 }; 49 50 static struct inode *fuse_alloc_inode(struct super_block *sb) 51 { 52 struct inode *inode; 53 struct fuse_inode *fi; 54 55 inode = kmem_cache_alloc(fuse_inode_cachep, GFP_KERNEL); 56 if (!inode) 57 return NULL; 58 59 fi = get_fuse_inode(inode); 60 fi->i_time = 0; 61 fi->nodeid = 0; 62 fi->nlookup = 0; 63 fi->attr_version = 0; 64 fi->writectr = 0; 65 INIT_LIST_HEAD(&fi->write_files); 66 INIT_LIST_HEAD(&fi->queued_writes); 67 INIT_LIST_HEAD(&fi->writepages); 68 init_waitqueue_head(&fi->page_waitq); 69 fi->forget_req = fuse_request_alloc(); 70 if (!fi->forget_req) { 71 kmem_cache_free(fuse_inode_cachep, inode); 72 return NULL; 73 } 74 75 return inode; 76 } 77 78 static void fuse_destroy_inode(struct inode *inode) 79 { 80 struct fuse_inode *fi = get_fuse_inode(inode); 81 BUG_ON(!list_empty(&fi->write_files)); 82 BUG_ON(!list_empty(&fi->queued_writes)); 83 if (fi->forget_req) 84 fuse_request_free(fi->forget_req); 85 kmem_cache_free(fuse_inode_cachep, inode); 86 } 87 88 void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req, 89 u64 nodeid, u64 nlookup) 90 { 91 struct fuse_forget_in *inarg = &req->misc.forget_in; 92 inarg->nlookup = nlookup; 93 req->in.h.opcode = FUSE_FORGET; 94 req->in.h.nodeid = nodeid; 95 req->in.numargs = 1; 96 req->in.args[0].size = sizeof(struct fuse_forget_in); 97 req->in.args[0].value = inarg; 98 fuse_request_send_noreply(fc, req); 99 } 100 101 static void fuse_clear_inode(struct inode *inode) 102 { 103 if (inode->i_sb->s_flags & MS_ACTIVE) { 104 struct fuse_conn *fc = get_fuse_conn(inode); 105 struct fuse_inode *fi = get_fuse_inode(inode); 106 fuse_send_forget(fc, fi->forget_req, fi->nodeid, fi->nlookup); 107 fi->forget_req = NULL; 108 } 109 } 110 111 static int fuse_remount_fs(struct super_block *sb, int *flags, char *data) 112 { 113 if (*flags & MS_MANDLOCK) 114 return -EINVAL; 115 116 return 0; 117 } 118 119 void fuse_truncate(struct address_space *mapping, loff_t offset) 120 { 121 /* See vmtruncate() */ 122 unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1); 123 truncate_inode_pages(mapping, offset); 124 unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1); 125 } 126 127 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr, 128 u64 attr_valid) 129 { 130 struct fuse_conn *fc = get_fuse_conn(inode); 131 struct fuse_inode *fi = get_fuse_inode(inode); 132 133 fi->attr_version = ++fc->attr_version; 134 fi->i_time = attr_valid; 135 136 inode->i_ino = attr->ino; 137 inode->i_mode = (inode->i_mode & S_IFMT) | (attr->mode & 07777); 138 inode->i_nlink = attr->nlink; 139 inode->i_uid = attr->uid; 140 inode->i_gid = attr->gid; 141 inode->i_blocks = attr->blocks; 142 inode->i_atime.tv_sec = attr->atime; 143 inode->i_atime.tv_nsec = attr->atimensec; 144 inode->i_mtime.tv_sec = attr->mtime; 145 inode->i_mtime.tv_nsec = attr->mtimensec; 146 inode->i_ctime.tv_sec = attr->ctime; 147 inode->i_ctime.tv_nsec = attr->ctimensec; 148 149 if (attr->blksize != 0) 150 inode->i_blkbits = ilog2(attr->blksize); 151 else 152 inode->i_blkbits = inode->i_sb->s_blocksize_bits; 153 154 /* 155 * Don't set the sticky bit in i_mode, unless we want the VFS 156 * to check permissions. This prevents failures due to the 157 * check in may_delete(). 158 */ 159 fi->orig_i_mode = inode->i_mode; 160 if (!(fc->flags & FUSE_DEFAULT_PERMISSIONS)) 161 inode->i_mode &= ~S_ISVTX; 162 } 163 164 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr, 165 u64 attr_valid, u64 attr_version) 166 { 167 struct fuse_conn *fc = get_fuse_conn(inode); 168 struct fuse_inode *fi = get_fuse_inode(inode); 169 loff_t oldsize; 170 171 spin_lock(&fc->lock); 172 if (attr_version != 0 && fi->attr_version > attr_version) { 173 spin_unlock(&fc->lock); 174 return; 175 } 176 177 fuse_change_attributes_common(inode, attr, attr_valid); 178 179 oldsize = inode->i_size; 180 i_size_write(inode, attr->size); 181 spin_unlock(&fc->lock); 182 183 if (S_ISREG(inode->i_mode) && oldsize != attr->size) { 184 if (attr->size < oldsize) 185 fuse_truncate(inode->i_mapping, attr->size); 186 invalidate_inode_pages2(inode->i_mapping); 187 } 188 } 189 190 static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr) 191 { 192 inode->i_mode = attr->mode & S_IFMT; 193 inode->i_size = attr->size; 194 if (S_ISREG(inode->i_mode)) { 195 fuse_init_common(inode); 196 fuse_init_file_inode(inode); 197 } else if (S_ISDIR(inode->i_mode)) 198 fuse_init_dir(inode); 199 else if (S_ISLNK(inode->i_mode)) 200 fuse_init_symlink(inode); 201 else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) || 202 S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) { 203 fuse_init_common(inode); 204 init_special_inode(inode, inode->i_mode, 205 new_decode_dev(attr->rdev)); 206 } else 207 BUG(); 208 } 209 210 static int fuse_inode_eq(struct inode *inode, void *_nodeidp) 211 { 212 u64 nodeid = *(u64 *) _nodeidp; 213 if (get_node_id(inode) == nodeid) 214 return 1; 215 else 216 return 0; 217 } 218 219 static int fuse_inode_set(struct inode *inode, void *_nodeidp) 220 { 221 u64 nodeid = *(u64 *) _nodeidp; 222 get_fuse_inode(inode)->nodeid = nodeid; 223 return 0; 224 } 225 226 struct inode *fuse_iget(struct super_block *sb, u64 nodeid, 227 int generation, struct fuse_attr *attr, 228 u64 attr_valid, u64 attr_version) 229 { 230 struct inode *inode; 231 struct fuse_inode *fi; 232 struct fuse_conn *fc = get_fuse_conn_super(sb); 233 234 retry: 235 inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid); 236 if (!inode) 237 return NULL; 238 239 if ((inode->i_state & I_NEW)) { 240 inode->i_flags |= S_NOATIME|S_NOCMTIME; 241 inode->i_generation = generation; 242 inode->i_data.backing_dev_info = &fc->bdi; 243 fuse_init_inode(inode, attr); 244 unlock_new_inode(inode); 245 } else if ((inode->i_mode ^ attr->mode) & S_IFMT) { 246 /* Inode has changed type, any I/O on the old should fail */ 247 make_bad_inode(inode); 248 iput(inode); 249 goto retry; 250 } 251 252 fi = get_fuse_inode(inode); 253 spin_lock(&fc->lock); 254 fi->nlookup++; 255 spin_unlock(&fc->lock); 256 fuse_change_attributes(inode, attr, attr_valid, attr_version); 257 258 return inode; 259 } 260 261 static void fuse_umount_begin(struct super_block *sb) 262 { 263 lock_kernel(); 264 fuse_abort_conn(get_fuse_conn_super(sb)); 265 unlock_kernel(); 266 } 267 268 static void fuse_send_destroy(struct fuse_conn *fc) 269 { 270 struct fuse_req *req = fc->destroy_req; 271 if (req && fc->conn_init) { 272 fc->destroy_req = NULL; 273 req->in.h.opcode = FUSE_DESTROY; 274 req->force = 1; 275 fuse_request_send(fc, req); 276 fuse_put_request(fc, req); 277 } 278 } 279 280 static void fuse_put_super(struct super_block *sb) 281 { 282 struct fuse_conn *fc = get_fuse_conn_super(sb); 283 284 fuse_send_destroy(fc); 285 spin_lock(&fc->lock); 286 fc->connected = 0; 287 fc->blocked = 0; 288 spin_unlock(&fc->lock); 289 /* Flush all readers on this fs */ 290 kill_fasync(&fc->fasync, SIGIO, POLL_IN); 291 wake_up_all(&fc->waitq); 292 wake_up_all(&fc->blocked_waitq); 293 wake_up_all(&fc->reserved_req_waitq); 294 mutex_lock(&fuse_mutex); 295 list_del(&fc->entry); 296 fuse_ctl_remove_conn(fc); 297 mutex_unlock(&fuse_mutex); 298 bdi_destroy(&fc->bdi); 299 fuse_conn_put(fc); 300 } 301 302 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr) 303 { 304 stbuf->f_type = FUSE_SUPER_MAGIC; 305 stbuf->f_bsize = attr->bsize; 306 stbuf->f_frsize = attr->frsize; 307 stbuf->f_blocks = attr->blocks; 308 stbuf->f_bfree = attr->bfree; 309 stbuf->f_bavail = attr->bavail; 310 stbuf->f_files = attr->files; 311 stbuf->f_ffree = attr->ffree; 312 stbuf->f_namelen = attr->namelen; 313 /* fsid is left zero */ 314 } 315 316 static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf) 317 { 318 struct super_block *sb = dentry->d_sb; 319 struct fuse_conn *fc = get_fuse_conn_super(sb); 320 struct fuse_req *req; 321 struct fuse_statfs_out outarg; 322 int err; 323 324 if (!fuse_allow_task(fc, current)) { 325 buf->f_type = FUSE_SUPER_MAGIC; 326 return 0; 327 } 328 329 req = fuse_get_req(fc); 330 if (IS_ERR(req)) 331 return PTR_ERR(req); 332 333 memset(&outarg, 0, sizeof(outarg)); 334 req->in.numargs = 0; 335 req->in.h.opcode = FUSE_STATFS; 336 req->in.h.nodeid = get_node_id(dentry->d_inode); 337 req->out.numargs = 1; 338 req->out.args[0].size = 339 fc->minor < 4 ? FUSE_COMPAT_STATFS_SIZE : sizeof(outarg); 340 req->out.args[0].value = &outarg; 341 fuse_request_send(fc, req); 342 err = req->out.h.error; 343 if (!err) 344 convert_fuse_statfs(buf, &outarg.st); 345 fuse_put_request(fc, req); 346 return err; 347 } 348 349 enum { 350 OPT_FD, 351 OPT_ROOTMODE, 352 OPT_USER_ID, 353 OPT_GROUP_ID, 354 OPT_DEFAULT_PERMISSIONS, 355 OPT_ALLOW_OTHER, 356 OPT_MAX_READ, 357 OPT_BLKSIZE, 358 OPT_ERR 359 }; 360 361 static const match_table_t tokens = { 362 {OPT_FD, "fd=%u"}, 363 {OPT_ROOTMODE, "rootmode=%o"}, 364 {OPT_USER_ID, "user_id=%u"}, 365 {OPT_GROUP_ID, "group_id=%u"}, 366 {OPT_DEFAULT_PERMISSIONS, "default_permissions"}, 367 {OPT_ALLOW_OTHER, "allow_other"}, 368 {OPT_MAX_READ, "max_read=%u"}, 369 {OPT_BLKSIZE, "blksize=%u"}, 370 {OPT_ERR, NULL} 371 }; 372 373 static int parse_fuse_opt(char *opt, struct fuse_mount_data *d, int is_bdev) 374 { 375 char *p; 376 memset(d, 0, sizeof(struct fuse_mount_data)); 377 d->max_read = ~0; 378 d->blksize = FUSE_DEFAULT_BLKSIZE; 379 380 while ((p = strsep(&opt, ",")) != NULL) { 381 int token; 382 int value; 383 substring_t args[MAX_OPT_ARGS]; 384 if (!*p) 385 continue; 386 387 token = match_token(p, tokens, args); 388 switch (token) { 389 case OPT_FD: 390 if (match_int(&args[0], &value)) 391 return 0; 392 d->fd = value; 393 d->fd_present = 1; 394 break; 395 396 case OPT_ROOTMODE: 397 if (match_octal(&args[0], &value)) 398 return 0; 399 if (!fuse_valid_type(value)) 400 return 0; 401 d->rootmode = value; 402 d->rootmode_present = 1; 403 break; 404 405 case OPT_USER_ID: 406 if (match_int(&args[0], &value)) 407 return 0; 408 d->user_id = value; 409 d->user_id_present = 1; 410 break; 411 412 case OPT_GROUP_ID: 413 if (match_int(&args[0], &value)) 414 return 0; 415 d->group_id = value; 416 d->group_id_present = 1; 417 break; 418 419 case OPT_DEFAULT_PERMISSIONS: 420 d->flags |= FUSE_DEFAULT_PERMISSIONS; 421 break; 422 423 case OPT_ALLOW_OTHER: 424 d->flags |= FUSE_ALLOW_OTHER; 425 break; 426 427 case OPT_MAX_READ: 428 if (match_int(&args[0], &value)) 429 return 0; 430 d->max_read = value; 431 break; 432 433 case OPT_BLKSIZE: 434 if (!is_bdev || match_int(&args[0], &value)) 435 return 0; 436 d->blksize = value; 437 break; 438 439 default: 440 return 0; 441 } 442 } 443 444 if (!d->fd_present || !d->rootmode_present || 445 !d->user_id_present || !d->group_id_present) 446 return 0; 447 448 return 1; 449 } 450 451 static int fuse_show_options(struct seq_file *m, struct vfsmount *mnt) 452 { 453 struct fuse_conn *fc = get_fuse_conn_super(mnt->mnt_sb); 454 455 seq_printf(m, ",user_id=%u", fc->user_id); 456 seq_printf(m, ",group_id=%u", fc->group_id); 457 if (fc->flags & FUSE_DEFAULT_PERMISSIONS) 458 seq_puts(m, ",default_permissions"); 459 if (fc->flags & FUSE_ALLOW_OTHER) 460 seq_puts(m, ",allow_other"); 461 if (fc->max_read != ~0) 462 seq_printf(m, ",max_read=%u", fc->max_read); 463 if (mnt->mnt_sb->s_bdev && 464 mnt->mnt_sb->s_blocksize != FUSE_DEFAULT_BLKSIZE) 465 seq_printf(m, ",blksize=%lu", mnt->mnt_sb->s_blocksize); 466 return 0; 467 } 468 469 int fuse_conn_init(struct fuse_conn *fc, struct super_block *sb) 470 { 471 int err; 472 473 memset(fc, 0, sizeof(*fc)); 474 spin_lock_init(&fc->lock); 475 mutex_init(&fc->inst_mutex); 476 atomic_set(&fc->count, 1); 477 init_waitqueue_head(&fc->waitq); 478 init_waitqueue_head(&fc->blocked_waitq); 479 init_waitqueue_head(&fc->reserved_req_waitq); 480 INIT_LIST_HEAD(&fc->pending); 481 INIT_LIST_HEAD(&fc->processing); 482 INIT_LIST_HEAD(&fc->io); 483 INIT_LIST_HEAD(&fc->interrupts); 484 INIT_LIST_HEAD(&fc->bg_queue); 485 INIT_LIST_HEAD(&fc->entry); 486 atomic_set(&fc->num_waiting, 0); 487 fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE; 488 fc->bdi.unplug_io_fn = default_unplug_io_fn; 489 /* fuse does it's own writeback accounting */ 490 fc->bdi.capabilities = BDI_CAP_NO_ACCT_WB; 491 fc->khctr = 0; 492 fc->polled_files = RB_ROOT; 493 fc->dev = sb->s_dev; 494 err = bdi_init(&fc->bdi); 495 if (err) 496 goto error_mutex_destroy; 497 if (sb->s_bdev) { 498 err = bdi_register(&fc->bdi, NULL, "%u:%u-fuseblk", 499 MAJOR(fc->dev), MINOR(fc->dev)); 500 } else { 501 err = bdi_register_dev(&fc->bdi, fc->dev); 502 } 503 if (err) 504 goto error_bdi_destroy; 505 /* 506 * For a single fuse filesystem use max 1% of dirty + 507 * writeback threshold. 508 * 509 * This gives about 1M of write buffer for memory maps on a 510 * machine with 1G and 10% dirty_ratio, which should be more 511 * than enough. 512 * 513 * Privileged users can raise it by writing to 514 * 515 * /sys/class/bdi/<bdi>/max_ratio 516 */ 517 bdi_set_max_ratio(&fc->bdi, 1); 518 fc->reqctr = 0; 519 fc->blocked = 1; 520 fc->attr_version = 1; 521 get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key)); 522 523 return 0; 524 525 error_bdi_destroy: 526 bdi_destroy(&fc->bdi); 527 error_mutex_destroy: 528 mutex_destroy(&fc->inst_mutex); 529 return err; 530 } 531 EXPORT_SYMBOL_GPL(fuse_conn_init); 532 533 void fuse_conn_put(struct fuse_conn *fc) 534 { 535 if (atomic_dec_and_test(&fc->count)) { 536 if (fc->destroy_req) 537 fuse_request_free(fc->destroy_req); 538 mutex_destroy(&fc->inst_mutex); 539 fc->release(fc); 540 } 541 } 542 543 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc) 544 { 545 atomic_inc(&fc->count); 546 return fc; 547 } 548 549 static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned mode) 550 { 551 struct fuse_attr attr; 552 memset(&attr, 0, sizeof(attr)); 553 554 attr.mode = mode; 555 attr.ino = FUSE_ROOT_ID; 556 attr.nlink = 1; 557 return fuse_iget(sb, 1, 0, &attr, 0, 0); 558 } 559 560 struct fuse_inode_handle { 561 u64 nodeid; 562 u32 generation; 563 }; 564 565 static struct dentry *fuse_get_dentry(struct super_block *sb, 566 struct fuse_inode_handle *handle) 567 { 568 struct fuse_conn *fc = get_fuse_conn_super(sb); 569 struct inode *inode; 570 struct dentry *entry; 571 int err = -ESTALE; 572 573 if (handle->nodeid == 0) 574 goto out_err; 575 576 inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid); 577 if (!inode) { 578 struct fuse_entry_out outarg; 579 struct qstr name; 580 581 if (!fc->export_support) 582 goto out_err; 583 584 name.len = 1; 585 name.name = "."; 586 err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg, 587 &inode); 588 if (err && err != -ENOENT) 589 goto out_err; 590 if (err || !inode) { 591 err = -ESTALE; 592 goto out_err; 593 } 594 err = -EIO; 595 if (get_node_id(inode) != handle->nodeid) 596 goto out_iput; 597 } 598 err = -ESTALE; 599 if (inode->i_generation != handle->generation) 600 goto out_iput; 601 602 entry = d_obtain_alias(inode); 603 if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID) { 604 entry->d_op = &fuse_dentry_operations; 605 fuse_invalidate_entry_cache(entry); 606 } 607 608 return entry; 609 610 out_iput: 611 iput(inode); 612 out_err: 613 return ERR_PTR(err); 614 } 615 616 static int fuse_encode_fh(struct dentry *dentry, u32 *fh, int *max_len, 617 int connectable) 618 { 619 struct inode *inode = dentry->d_inode; 620 bool encode_parent = connectable && !S_ISDIR(inode->i_mode); 621 int len = encode_parent ? 6 : 3; 622 u64 nodeid; 623 u32 generation; 624 625 if (*max_len < len) 626 return 255; 627 628 nodeid = get_fuse_inode(inode)->nodeid; 629 generation = inode->i_generation; 630 631 fh[0] = (u32)(nodeid >> 32); 632 fh[1] = (u32)(nodeid & 0xffffffff); 633 fh[2] = generation; 634 635 if (encode_parent) { 636 struct inode *parent; 637 638 spin_lock(&dentry->d_lock); 639 parent = dentry->d_parent->d_inode; 640 nodeid = get_fuse_inode(parent)->nodeid; 641 generation = parent->i_generation; 642 spin_unlock(&dentry->d_lock); 643 644 fh[3] = (u32)(nodeid >> 32); 645 fh[4] = (u32)(nodeid & 0xffffffff); 646 fh[5] = generation; 647 } 648 649 *max_len = len; 650 return encode_parent ? 0x82 : 0x81; 651 } 652 653 static struct dentry *fuse_fh_to_dentry(struct super_block *sb, 654 struct fid *fid, int fh_len, int fh_type) 655 { 656 struct fuse_inode_handle handle; 657 658 if ((fh_type != 0x81 && fh_type != 0x82) || fh_len < 3) 659 return NULL; 660 661 handle.nodeid = (u64) fid->raw[0] << 32; 662 handle.nodeid |= (u64) fid->raw[1]; 663 handle.generation = fid->raw[2]; 664 return fuse_get_dentry(sb, &handle); 665 } 666 667 static struct dentry *fuse_fh_to_parent(struct super_block *sb, 668 struct fid *fid, int fh_len, int fh_type) 669 { 670 struct fuse_inode_handle parent; 671 672 if (fh_type != 0x82 || fh_len < 6) 673 return NULL; 674 675 parent.nodeid = (u64) fid->raw[3] << 32; 676 parent.nodeid |= (u64) fid->raw[4]; 677 parent.generation = fid->raw[5]; 678 return fuse_get_dentry(sb, &parent); 679 } 680 681 static struct dentry *fuse_get_parent(struct dentry *child) 682 { 683 struct inode *child_inode = child->d_inode; 684 struct fuse_conn *fc = get_fuse_conn(child_inode); 685 struct inode *inode; 686 struct dentry *parent; 687 struct fuse_entry_out outarg; 688 struct qstr name; 689 int err; 690 691 if (!fc->export_support) 692 return ERR_PTR(-ESTALE); 693 694 name.len = 2; 695 name.name = ".."; 696 err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode), 697 &name, &outarg, &inode); 698 if (err) { 699 if (err == -ENOENT) 700 return ERR_PTR(-ESTALE); 701 return ERR_PTR(err); 702 } 703 704 parent = d_obtain_alias(inode); 705 if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID) { 706 parent->d_op = &fuse_dentry_operations; 707 fuse_invalidate_entry_cache(parent); 708 } 709 710 return parent; 711 } 712 713 static const struct export_operations fuse_export_operations = { 714 .fh_to_dentry = fuse_fh_to_dentry, 715 .fh_to_parent = fuse_fh_to_parent, 716 .encode_fh = fuse_encode_fh, 717 .get_parent = fuse_get_parent, 718 }; 719 720 static const struct super_operations fuse_super_operations = { 721 .alloc_inode = fuse_alloc_inode, 722 .destroy_inode = fuse_destroy_inode, 723 .clear_inode = fuse_clear_inode, 724 .drop_inode = generic_delete_inode, 725 .remount_fs = fuse_remount_fs, 726 .put_super = fuse_put_super, 727 .umount_begin = fuse_umount_begin, 728 .statfs = fuse_statfs, 729 .show_options = fuse_show_options, 730 }; 731 732 static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req) 733 { 734 struct fuse_init_out *arg = &req->misc.init_out; 735 736 if (req->out.h.error || arg->major != FUSE_KERNEL_VERSION) 737 fc->conn_error = 1; 738 else { 739 unsigned long ra_pages; 740 741 if (arg->minor >= 6) { 742 ra_pages = arg->max_readahead / PAGE_CACHE_SIZE; 743 if (arg->flags & FUSE_ASYNC_READ) 744 fc->async_read = 1; 745 if (!(arg->flags & FUSE_POSIX_LOCKS)) 746 fc->no_lock = 1; 747 if (arg->flags & FUSE_ATOMIC_O_TRUNC) 748 fc->atomic_o_trunc = 1; 749 if (arg->minor >= 9) { 750 /* LOOKUP has dependency on proto version */ 751 if (arg->flags & FUSE_EXPORT_SUPPORT) 752 fc->export_support = 1; 753 } 754 if (arg->flags & FUSE_BIG_WRITES) 755 fc->big_writes = 1; 756 } else { 757 ra_pages = fc->max_read / PAGE_CACHE_SIZE; 758 fc->no_lock = 1; 759 } 760 761 fc->bdi.ra_pages = min(fc->bdi.ra_pages, ra_pages); 762 fc->minor = arg->minor; 763 fc->max_write = arg->minor < 5 ? 4096 : arg->max_write; 764 fc->max_write = max_t(unsigned, 4096, fc->max_write); 765 fc->conn_init = 1; 766 } 767 fc->blocked = 0; 768 wake_up_all(&fc->blocked_waitq); 769 } 770 771 static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req) 772 { 773 struct fuse_init_in *arg = &req->misc.init_in; 774 775 arg->major = FUSE_KERNEL_VERSION; 776 arg->minor = FUSE_KERNEL_MINOR_VERSION; 777 arg->max_readahead = fc->bdi.ra_pages * PAGE_CACHE_SIZE; 778 arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC | 779 FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES; 780 req->in.h.opcode = FUSE_INIT; 781 req->in.numargs = 1; 782 req->in.args[0].size = sizeof(*arg); 783 req->in.args[0].value = arg; 784 req->out.numargs = 1; 785 /* Variable length arguement used for backward compatibility 786 with interface version < 7.5. Rest of init_out is zeroed 787 by do_get_request(), so a short reply is not a problem */ 788 req->out.argvar = 1; 789 req->out.args[0].size = sizeof(struct fuse_init_out); 790 req->out.args[0].value = &req->misc.init_out; 791 req->end = process_init_reply; 792 fuse_request_send_background(fc, req); 793 } 794 795 static void fuse_free_conn(struct fuse_conn *fc) 796 { 797 kfree(fc); 798 } 799 800 static int fuse_fill_super(struct super_block *sb, void *data, int silent) 801 { 802 struct fuse_conn *fc; 803 struct inode *root; 804 struct fuse_mount_data d; 805 struct file *file; 806 struct dentry *root_dentry; 807 struct fuse_req *init_req; 808 int err; 809 int is_bdev = sb->s_bdev != NULL; 810 811 err = -EINVAL; 812 if (sb->s_flags & MS_MANDLOCK) 813 goto err; 814 815 if (!parse_fuse_opt((char *) data, &d, is_bdev)) 816 goto err; 817 818 if (is_bdev) { 819 #ifdef CONFIG_BLOCK 820 err = -EINVAL; 821 if (!sb_set_blocksize(sb, d.blksize)) 822 goto err; 823 #endif 824 } else { 825 sb->s_blocksize = PAGE_CACHE_SIZE; 826 sb->s_blocksize_bits = PAGE_CACHE_SHIFT; 827 } 828 sb->s_magic = FUSE_SUPER_MAGIC; 829 sb->s_op = &fuse_super_operations; 830 sb->s_maxbytes = MAX_LFS_FILESIZE; 831 sb->s_export_op = &fuse_export_operations; 832 833 file = fget(d.fd); 834 err = -EINVAL; 835 if (!file) 836 goto err; 837 838 if (file->f_op != &fuse_dev_operations) 839 goto err_fput; 840 841 fc = kmalloc(sizeof(*fc), GFP_KERNEL); 842 err = -ENOMEM; 843 if (!fc) 844 goto err_fput; 845 846 err = fuse_conn_init(fc, sb); 847 if (err) { 848 kfree(fc); 849 goto err_fput; 850 } 851 852 fc->release = fuse_free_conn; 853 fc->flags = d.flags; 854 fc->user_id = d.user_id; 855 fc->group_id = d.group_id; 856 fc->max_read = max_t(unsigned, 4096, d.max_read); 857 858 /* Used by get_root_inode() */ 859 sb->s_fs_info = fc; 860 861 err = -ENOMEM; 862 root = fuse_get_root_inode(sb, d.rootmode); 863 if (!root) 864 goto err_put_conn; 865 866 root_dentry = d_alloc_root(root); 867 if (!root_dentry) { 868 iput(root); 869 goto err_put_conn; 870 } 871 872 init_req = fuse_request_alloc(); 873 if (!init_req) 874 goto err_put_root; 875 876 if (is_bdev) { 877 fc->destroy_req = fuse_request_alloc(); 878 if (!fc->destroy_req) 879 goto err_free_init_req; 880 } 881 882 mutex_lock(&fuse_mutex); 883 err = -EINVAL; 884 if (file->private_data) 885 goto err_unlock; 886 887 err = fuse_ctl_add_conn(fc); 888 if (err) 889 goto err_unlock; 890 891 list_add_tail(&fc->entry, &fuse_conn_list); 892 sb->s_root = root_dentry; 893 fc->connected = 1; 894 file->private_data = fuse_conn_get(fc); 895 mutex_unlock(&fuse_mutex); 896 /* 897 * atomic_dec_and_test() in fput() provides the necessary 898 * memory barrier for file->private_data to be visible on all 899 * CPUs after this 900 */ 901 fput(file); 902 903 fuse_send_init(fc, init_req); 904 905 return 0; 906 907 err_unlock: 908 mutex_unlock(&fuse_mutex); 909 err_free_init_req: 910 fuse_request_free(init_req); 911 err_put_root: 912 dput(root_dentry); 913 err_put_conn: 914 bdi_destroy(&fc->bdi); 915 fuse_conn_put(fc); 916 err_fput: 917 fput(file); 918 err: 919 return err; 920 } 921 922 static int fuse_get_sb(struct file_system_type *fs_type, 923 int flags, const char *dev_name, 924 void *raw_data, struct vfsmount *mnt) 925 { 926 return get_sb_nodev(fs_type, flags, raw_data, fuse_fill_super, mnt); 927 } 928 929 static struct file_system_type fuse_fs_type = { 930 .owner = THIS_MODULE, 931 .name = "fuse", 932 .fs_flags = FS_HAS_SUBTYPE, 933 .get_sb = fuse_get_sb, 934 .kill_sb = kill_anon_super, 935 }; 936 937 #ifdef CONFIG_BLOCK 938 static int fuse_get_sb_blk(struct file_system_type *fs_type, 939 int flags, const char *dev_name, 940 void *raw_data, struct vfsmount *mnt) 941 { 942 return get_sb_bdev(fs_type, flags, dev_name, raw_data, fuse_fill_super, 943 mnt); 944 } 945 946 static struct file_system_type fuseblk_fs_type = { 947 .owner = THIS_MODULE, 948 .name = "fuseblk", 949 .get_sb = fuse_get_sb_blk, 950 .kill_sb = kill_block_super, 951 .fs_flags = FS_REQUIRES_DEV | FS_HAS_SUBTYPE, 952 }; 953 954 static inline int register_fuseblk(void) 955 { 956 return register_filesystem(&fuseblk_fs_type); 957 } 958 959 static inline void unregister_fuseblk(void) 960 { 961 unregister_filesystem(&fuseblk_fs_type); 962 } 963 #else 964 static inline int register_fuseblk(void) 965 { 966 return 0; 967 } 968 969 static inline void unregister_fuseblk(void) 970 { 971 } 972 #endif 973 974 static void fuse_inode_init_once(void *foo) 975 { 976 struct inode *inode = foo; 977 978 inode_init_once(inode); 979 } 980 981 static int __init fuse_fs_init(void) 982 { 983 int err; 984 985 err = register_filesystem(&fuse_fs_type); 986 if (err) 987 goto out; 988 989 err = register_fuseblk(); 990 if (err) 991 goto out_unreg; 992 993 fuse_inode_cachep = kmem_cache_create("fuse_inode", 994 sizeof(struct fuse_inode), 995 0, SLAB_HWCACHE_ALIGN, 996 fuse_inode_init_once); 997 err = -ENOMEM; 998 if (!fuse_inode_cachep) 999 goto out_unreg2; 1000 1001 return 0; 1002 1003 out_unreg2: 1004 unregister_fuseblk(); 1005 out_unreg: 1006 unregister_filesystem(&fuse_fs_type); 1007 out: 1008 return err; 1009 } 1010 1011 static void fuse_fs_cleanup(void) 1012 { 1013 unregister_filesystem(&fuse_fs_type); 1014 unregister_fuseblk(); 1015 kmem_cache_destroy(fuse_inode_cachep); 1016 } 1017 1018 static struct kobject *fuse_kobj; 1019 static struct kobject *connections_kobj; 1020 1021 static int fuse_sysfs_init(void) 1022 { 1023 int err; 1024 1025 fuse_kobj = kobject_create_and_add("fuse", fs_kobj); 1026 if (!fuse_kobj) { 1027 err = -ENOMEM; 1028 goto out_err; 1029 } 1030 1031 connections_kobj = kobject_create_and_add("connections", fuse_kobj); 1032 if (!connections_kobj) { 1033 err = -ENOMEM; 1034 goto out_fuse_unregister; 1035 } 1036 1037 return 0; 1038 1039 out_fuse_unregister: 1040 kobject_put(fuse_kobj); 1041 out_err: 1042 return err; 1043 } 1044 1045 static void fuse_sysfs_cleanup(void) 1046 { 1047 kobject_put(connections_kobj); 1048 kobject_put(fuse_kobj); 1049 } 1050 1051 static int __init fuse_init(void) 1052 { 1053 int res; 1054 1055 printk(KERN_INFO "fuse init (API version %i.%i)\n", 1056 FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION); 1057 1058 INIT_LIST_HEAD(&fuse_conn_list); 1059 res = fuse_fs_init(); 1060 if (res) 1061 goto err; 1062 1063 res = fuse_dev_init(); 1064 if (res) 1065 goto err_fs_cleanup; 1066 1067 res = fuse_sysfs_init(); 1068 if (res) 1069 goto err_dev_cleanup; 1070 1071 res = fuse_ctl_init(); 1072 if (res) 1073 goto err_sysfs_cleanup; 1074 1075 return 0; 1076 1077 err_sysfs_cleanup: 1078 fuse_sysfs_cleanup(); 1079 err_dev_cleanup: 1080 fuse_dev_cleanup(); 1081 err_fs_cleanup: 1082 fuse_fs_cleanup(); 1083 err: 1084 return res; 1085 } 1086 1087 static void __exit fuse_exit(void) 1088 { 1089 printk(KERN_DEBUG "fuse exit\n"); 1090 1091 fuse_ctl_cleanup(); 1092 fuse_sysfs_cleanup(); 1093 fuse_fs_cleanup(); 1094 fuse_dev_cleanup(); 1095 } 1096 1097 module_init(fuse_init); 1098 module_exit(fuse_exit); 1099