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_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 atomic_set(&fc->num_waiting, 0); 536 fc->max_background = FUSE_DEFAULT_MAX_BACKGROUND; 537 fc->congestion_threshold = FUSE_DEFAULT_CONGESTION_THRESHOLD; 538 fc->khctr = 0; 539 fc->polled_files = RB_ROOT; 540 fc->reqctr = 0; 541 fc->blocked = 1; 542 fc->attr_version = 1; 543 get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key)); 544 } 545 EXPORT_SYMBOL_GPL(fuse_conn_init); 546 547 void fuse_conn_put(struct fuse_conn *fc) 548 { 549 if (atomic_dec_and_test(&fc->count)) { 550 if (fc->destroy_req) 551 fuse_request_free(fc->destroy_req); 552 mutex_destroy(&fc->inst_mutex); 553 fc->release(fc); 554 } 555 } 556 EXPORT_SYMBOL_GPL(fuse_conn_put); 557 558 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc) 559 { 560 atomic_inc(&fc->count); 561 return fc; 562 } 563 EXPORT_SYMBOL_GPL(fuse_conn_get); 564 565 static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned mode) 566 { 567 struct fuse_attr attr; 568 memset(&attr, 0, sizeof(attr)); 569 570 attr.mode = mode; 571 attr.ino = FUSE_ROOT_ID; 572 attr.nlink = 1; 573 return fuse_iget(sb, 1, 0, &attr, 0, 0); 574 } 575 576 struct fuse_inode_handle { 577 u64 nodeid; 578 u32 generation; 579 }; 580 581 static struct dentry *fuse_get_dentry(struct super_block *sb, 582 struct fuse_inode_handle *handle) 583 { 584 struct fuse_conn *fc = get_fuse_conn_super(sb); 585 struct inode *inode; 586 struct dentry *entry; 587 int err = -ESTALE; 588 589 if (handle->nodeid == 0) 590 goto out_err; 591 592 inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid); 593 if (!inode) { 594 struct fuse_entry_out outarg; 595 struct qstr name; 596 597 if (!fc->export_support) 598 goto out_err; 599 600 name.len = 1; 601 name.name = "."; 602 err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg, 603 &inode); 604 if (err && err != -ENOENT) 605 goto out_err; 606 if (err || !inode) { 607 err = -ESTALE; 608 goto out_err; 609 } 610 err = -EIO; 611 if (get_node_id(inode) != handle->nodeid) 612 goto out_iput; 613 } 614 err = -ESTALE; 615 if (inode->i_generation != handle->generation) 616 goto out_iput; 617 618 entry = d_obtain_alias(inode); 619 if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID) { 620 entry->d_op = &fuse_dentry_operations; 621 fuse_invalidate_entry_cache(entry); 622 } 623 624 return entry; 625 626 out_iput: 627 iput(inode); 628 out_err: 629 return ERR_PTR(err); 630 } 631 632 static int fuse_encode_fh(struct dentry *dentry, u32 *fh, int *max_len, 633 int connectable) 634 { 635 struct inode *inode = dentry->d_inode; 636 bool encode_parent = connectable && !S_ISDIR(inode->i_mode); 637 int len = encode_parent ? 6 : 3; 638 u64 nodeid; 639 u32 generation; 640 641 if (*max_len < len) 642 return 255; 643 644 nodeid = get_fuse_inode(inode)->nodeid; 645 generation = inode->i_generation; 646 647 fh[0] = (u32)(nodeid >> 32); 648 fh[1] = (u32)(nodeid & 0xffffffff); 649 fh[2] = generation; 650 651 if (encode_parent) { 652 struct inode *parent; 653 654 spin_lock(&dentry->d_lock); 655 parent = dentry->d_parent->d_inode; 656 nodeid = get_fuse_inode(parent)->nodeid; 657 generation = parent->i_generation; 658 spin_unlock(&dentry->d_lock); 659 660 fh[3] = (u32)(nodeid >> 32); 661 fh[4] = (u32)(nodeid & 0xffffffff); 662 fh[5] = generation; 663 } 664 665 *max_len = len; 666 return encode_parent ? 0x82 : 0x81; 667 } 668 669 static struct dentry *fuse_fh_to_dentry(struct super_block *sb, 670 struct fid *fid, int fh_len, int fh_type) 671 { 672 struct fuse_inode_handle handle; 673 674 if ((fh_type != 0x81 && fh_type != 0x82) || fh_len < 3) 675 return NULL; 676 677 handle.nodeid = (u64) fid->raw[0] << 32; 678 handle.nodeid |= (u64) fid->raw[1]; 679 handle.generation = fid->raw[2]; 680 return fuse_get_dentry(sb, &handle); 681 } 682 683 static struct dentry *fuse_fh_to_parent(struct super_block *sb, 684 struct fid *fid, int fh_len, int fh_type) 685 { 686 struct fuse_inode_handle parent; 687 688 if (fh_type != 0x82 || fh_len < 6) 689 return NULL; 690 691 parent.nodeid = (u64) fid->raw[3] << 32; 692 parent.nodeid |= (u64) fid->raw[4]; 693 parent.generation = fid->raw[5]; 694 return fuse_get_dentry(sb, &parent); 695 } 696 697 static struct dentry *fuse_get_parent(struct dentry *child) 698 { 699 struct inode *child_inode = child->d_inode; 700 struct fuse_conn *fc = get_fuse_conn(child_inode); 701 struct inode *inode; 702 struct dentry *parent; 703 struct fuse_entry_out outarg; 704 struct qstr name; 705 int err; 706 707 if (!fc->export_support) 708 return ERR_PTR(-ESTALE); 709 710 name.len = 2; 711 name.name = ".."; 712 err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode), 713 &name, &outarg, &inode); 714 if (err) { 715 if (err == -ENOENT) 716 return ERR_PTR(-ESTALE); 717 return ERR_PTR(err); 718 } 719 720 parent = d_obtain_alias(inode); 721 if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID) { 722 parent->d_op = &fuse_dentry_operations; 723 fuse_invalidate_entry_cache(parent); 724 } 725 726 return parent; 727 } 728 729 static const struct export_operations fuse_export_operations = { 730 .fh_to_dentry = fuse_fh_to_dentry, 731 .fh_to_parent = fuse_fh_to_parent, 732 .encode_fh = fuse_encode_fh, 733 .get_parent = fuse_get_parent, 734 }; 735 736 static const struct super_operations fuse_super_operations = { 737 .alloc_inode = fuse_alloc_inode, 738 .destroy_inode = fuse_destroy_inode, 739 .clear_inode = fuse_clear_inode, 740 .drop_inode = generic_delete_inode, 741 .remount_fs = fuse_remount_fs, 742 .put_super = fuse_put_super, 743 .umount_begin = fuse_umount_begin, 744 .statfs = fuse_statfs, 745 .show_options = fuse_show_options, 746 }; 747 748 static void sanitize_global_limit(unsigned *limit) 749 { 750 if (*limit == 0) 751 *limit = ((num_physpages << PAGE_SHIFT) >> 13) / 752 sizeof(struct fuse_req); 753 754 if (*limit >= 1 << 16) 755 *limit = (1 << 16) - 1; 756 } 757 758 static int set_global_limit(const char *val, struct kernel_param *kp) 759 { 760 int rv; 761 762 rv = param_set_uint(val, kp); 763 if (rv) 764 return rv; 765 766 sanitize_global_limit((unsigned *)kp->arg); 767 768 return 0; 769 } 770 771 static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg) 772 { 773 int cap_sys_admin = capable(CAP_SYS_ADMIN); 774 775 if (arg->minor < 13) 776 return; 777 778 sanitize_global_limit(&max_user_bgreq); 779 sanitize_global_limit(&max_user_congthresh); 780 781 if (arg->max_background) { 782 fc->max_background = arg->max_background; 783 784 if (!cap_sys_admin && fc->max_background > max_user_bgreq) 785 fc->max_background = max_user_bgreq; 786 } 787 if (arg->congestion_threshold) { 788 fc->congestion_threshold = arg->congestion_threshold; 789 790 if (!cap_sys_admin && 791 fc->congestion_threshold > max_user_congthresh) 792 fc->congestion_threshold = max_user_congthresh; 793 } 794 } 795 796 static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req) 797 { 798 struct fuse_init_out *arg = &req->misc.init_out; 799 800 if (req->out.h.error || arg->major != FUSE_KERNEL_VERSION) 801 fc->conn_error = 1; 802 else { 803 unsigned long ra_pages; 804 805 process_init_limits(fc, arg); 806 807 if (arg->minor >= 6) { 808 ra_pages = arg->max_readahead / PAGE_CACHE_SIZE; 809 if (arg->flags & FUSE_ASYNC_READ) 810 fc->async_read = 1; 811 if (!(arg->flags & FUSE_POSIX_LOCKS)) 812 fc->no_lock = 1; 813 if (arg->flags & FUSE_ATOMIC_O_TRUNC) 814 fc->atomic_o_trunc = 1; 815 if (arg->minor >= 9) { 816 /* LOOKUP has dependency on proto version */ 817 if (arg->flags & FUSE_EXPORT_SUPPORT) 818 fc->export_support = 1; 819 } 820 if (arg->flags & FUSE_BIG_WRITES) 821 fc->big_writes = 1; 822 if (arg->flags & FUSE_DONT_MASK) 823 fc->dont_mask = 1; 824 } else { 825 ra_pages = fc->max_read / PAGE_CACHE_SIZE; 826 fc->no_lock = 1; 827 } 828 829 fc->bdi.ra_pages = min(fc->bdi.ra_pages, ra_pages); 830 fc->minor = arg->minor; 831 fc->max_write = arg->minor < 5 ? 4096 : arg->max_write; 832 fc->max_write = max_t(unsigned, 4096, fc->max_write); 833 fc->conn_init = 1; 834 } 835 fc->blocked = 0; 836 wake_up_all(&fc->blocked_waitq); 837 } 838 839 static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req) 840 { 841 struct fuse_init_in *arg = &req->misc.init_in; 842 843 arg->major = FUSE_KERNEL_VERSION; 844 arg->minor = FUSE_KERNEL_MINOR_VERSION; 845 arg->max_readahead = fc->bdi.ra_pages * PAGE_CACHE_SIZE; 846 arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC | 847 FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK; 848 req->in.h.opcode = FUSE_INIT; 849 req->in.numargs = 1; 850 req->in.args[0].size = sizeof(*arg); 851 req->in.args[0].value = arg; 852 req->out.numargs = 1; 853 /* Variable length arguement used for backward compatibility 854 with interface version < 7.5. Rest of init_out is zeroed 855 by do_get_request(), so a short reply is not a problem */ 856 req->out.argvar = 1; 857 req->out.args[0].size = sizeof(struct fuse_init_out); 858 req->out.args[0].value = &req->misc.init_out; 859 req->end = process_init_reply; 860 fuse_request_send_background(fc, req); 861 } 862 863 static void fuse_free_conn(struct fuse_conn *fc) 864 { 865 kfree(fc); 866 } 867 868 static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb) 869 { 870 int err; 871 872 fc->bdi.name = "fuse"; 873 fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE; 874 fc->bdi.unplug_io_fn = default_unplug_io_fn; 875 /* fuse does it's own writeback accounting */ 876 fc->bdi.capabilities = BDI_CAP_NO_ACCT_WB; 877 878 err = bdi_init(&fc->bdi); 879 if (err) 880 return err; 881 882 fc->bdi_initialized = 1; 883 884 if (sb->s_bdev) { 885 err = bdi_register(&fc->bdi, NULL, "%u:%u-fuseblk", 886 MAJOR(fc->dev), MINOR(fc->dev)); 887 } else { 888 err = bdi_register_dev(&fc->bdi, fc->dev); 889 } 890 891 if (err) 892 return err; 893 894 /* 895 * For a single fuse filesystem use max 1% of dirty + 896 * writeback threshold. 897 * 898 * This gives about 1M of write buffer for memory maps on a 899 * machine with 1G and 10% dirty_ratio, which should be more 900 * than enough. 901 * 902 * Privileged users can raise it by writing to 903 * 904 * /sys/class/bdi/<bdi>/max_ratio 905 */ 906 bdi_set_max_ratio(&fc->bdi, 1); 907 908 return 0; 909 } 910 911 static int fuse_fill_super(struct super_block *sb, void *data, int silent) 912 { 913 struct fuse_conn *fc; 914 struct inode *root; 915 struct fuse_mount_data d; 916 struct file *file; 917 struct dentry *root_dentry; 918 struct fuse_req *init_req; 919 int err; 920 int is_bdev = sb->s_bdev != NULL; 921 922 err = -EINVAL; 923 if (sb->s_flags & MS_MANDLOCK) 924 goto err; 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 } 991 992 init_req = fuse_request_alloc(); 993 if (!init_req) 994 goto err_put_root; 995 996 if (is_bdev) { 997 fc->destroy_req = fuse_request_alloc(); 998 if (!fc->destroy_req) 999 goto err_free_init_req; 1000 } 1001 1002 mutex_lock(&fuse_mutex); 1003 err = -EINVAL; 1004 if (file->private_data) 1005 goto err_unlock; 1006 1007 err = fuse_ctl_add_conn(fc); 1008 if (err) 1009 goto err_unlock; 1010 1011 list_add_tail(&fc->entry, &fuse_conn_list); 1012 sb->s_root = root_dentry; 1013 fc->connected = 1; 1014 file->private_data = fuse_conn_get(fc); 1015 mutex_unlock(&fuse_mutex); 1016 /* 1017 * atomic_dec_and_test() in fput() provides the necessary 1018 * memory barrier for file->private_data to be visible on all 1019 * CPUs after this 1020 */ 1021 fput(file); 1022 1023 fuse_send_init(fc, init_req); 1024 1025 return 0; 1026 1027 err_unlock: 1028 mutex_unlock(&fuse_mutex); 1029 err_free_init_req: 1030 fuse_request_free(init_req); 1031 err_put_root: 1032 dput(root_dentry); 1033 err_put_conn: 1034 fuse_bdi_destroy(fc); 1035 fuse_conn_put(fc); 1036 err_fput: 1037 fput(file); 1038 err: 1039 return err; 1040 } 1041 1042 static int fuse_get_sb(struct file_system_type *fs_type, 1043 int flags, const char *dev_name, 1044 void *raw_data, struct vfsmount *mnt) 1045 { 1046 return get_sb_nodev(fs_type, flags, raw_data, fuse_fill_super, mnt); 1047 } 1048 1049 static void fuse_kill_sb_anon(struct super_block *sb) 1050 { 1051 struct fuse_conn *fc = get_fuse_conn_super(sb); 1052 1053 if (fc) { 1054 down_write(&fc->killsb); 1055 fc->sb = NULL; 1056 up_write(&fc->killsb); 1057 } 1058 1059 kill_anon_super(sb); 1060 } 1061 1062 static struct file_system_type fuse_fs_type = { 1063 .owner = THIS_MODULE, 1064 .name = "fuse", 1065 .fs_flags = FS_HAS_SUBTYPE, 1066 .get_sb = fuse_get_sb, 1067 .kill_sb = fuse_kill_sb_anon, 1068 }; 1069 1070 #ifdef CONFIG_BLOCK 1071 static int fuse_get_sb_blk(struct file_system_type *fs_type, 1072 int flags, const char *dev_name, 1073 void *raw_data, struct vfsmount *mnt) 1074 { 1075 return get_sb_bdev(fs_type, flags, dev_name, raw_data, fuse_fill_super, 1076 mnt); 1077 } 1078 1079 static void fuse_kill_sb_blk(struct super_block *sb) 1080 { 1081 struct fuse_conn *fc = get_fuse_conn_super(sb); 1082 1083 if (fc) { 1084 down_write(&fc->killsb); 1085 fc->sb = NULL; 1086 up_write(&fc->killsb); 1087 } 1088 1089 kill_block_super(sb); 1090 } 1091 1092 static struct file_system_type fuseblk_fs_type = { 1093 .owner = THIS_MODULE, 1094 .name = "fuseblk", 1095 .get_sb = fuse_get_sb_blk, 1096 .kill_sb = fuse_kill_sb_blk, 1097 .fs_flags = FS_REQUIRES_DEV | FS_HAS_SUBTYPE, 1098 }; 1099 1100 static inline int register_fuseblk(void) 1101 { 1102 return register_filesystem(&fuseblk_fs_type); 1103 } 1104 1105 static inline void unregister_fuseblk(void) 1106 { 1107 unregister_filesystem(&fuseblk_fs_type); 1108 } 1109 #else 1110 static inline int register_fuseblk(void) 1111 { 1112 return 0; 1113 } 1114 1115 static inline void unregister_fuseblk(void) 1116 { 1117 } 1118 #endif 1119 1120 static void fuse_inode_init_once(void *foo) 1121 { 1122 struct inode *inode = foo; 1123 1124 inode_init_once(inode); 1125 } 1126 1127 static int __init fuse_fs_init(void) 1128 { 1129 int err; 1130 1131 err = register_filesystem(&fuse_fs_type); 1132 if (err) 1133 goto out; 1134 1135 err = register_fuseblk(); 1136 if (err) 1137 goto out_unreg; 1138 1139 fuse_inode_cachep = kmem_cache_create("fuse_inode", 1140 sizeof(struct fuse_inode), 1141 0, SLAB_HWCACHE_ALIGN, 1142 fuse_inode_init_once); 1143 err = -ENOMEM; 1144 if (!fuse_inode_cachep) 1145 goto out_unreg2; 1146 1147 return 0; 1148 1149 out_unreg2: 1150 unregister_fuseblk(); 1151 out_unreg: 1152 unregister_filesystem(&fuse_fs_type); 1153 out: 1154 return err; 1155 } 1156 1157 static void fuse_fs_cleanup(void) 1158 { 1159 unregister_filesystem(&fuse_fs_type); 1160 unregister_fuseblk(); 1161 kmem_cache_destroy(fuse_inode_cachep); 1162 } 1163 1164 static struct kobject *fuse_kobj; 1165 static struct kobject *connections_kobj; 1166 1167 static int fuse_sysfs_init(void) 1168 { 1169 int err; 1170 1171 fuse_kobj = kobject_create_and_add("fuse", fs_kobj); 1172 if (!fuse_kobj) { 1173 err = -ENOMEM; 1174 goto out_err; 1175 } 1176 1177 connections_kobj = kobject_create_and_add("connections", fuse_kobj); 1178 if (!connections_kobj) { 1179 err = -ENOMEM; 1180 goto out_fuse_unregister; 1181 } 1182 1183 return 0; 1184 1185 out_fuse_unregister: 1186 kobject_put(fuse_kobj); 1187 out_err: 1188 return err; 1189 } 1190 1191 static void fuse_sysfs_cleanup(void) 1192 { 1193 kobject_put(connections_kobj); 1194 kobject_put(fuse_kobj); 1195 } 1196 1197 static int __init fuse_init(void) 1198 { 1199 int res; 1200 1201 printk(KERN_INFO "fuse init (API version %i.%i)\n", 1202 FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION); 1203 1204 INIT_LIST_HEAD(&fuse_conn_list); 1205 res = fuse_fs_init(); 1206 if (res) 1207 goto err; 1208 1209 res = fuse_dev_init(); 1210 if (res) 1211 goto err_fs_cleanup; 1212 1213 res = fuse_sysfs_init(); 1214 if (res) 1215 goto err_dev_cleanup; 1216 1217 res = fuse_ctl_init(); 1218 if (res) 1219 goto err_sysfs_cleanup; 1220 1221 sanitize_global_limit(&max_user_bgreq); 1222 sanitize_global_limit(&max_user_congthresh); 1223 1224 return 0; 1225 1226 err_sysfs_cleanup: 1227 fuse_sysfs_cleanup(); 1228 err_dev_cleanup: 1229 fuse_dev_cleanup(); 1230 err_fs_cleanup: 1231 fuse_fs_cleanup(); 1232 err: 1233 return res; 1234 } 1235 1236 static void __exit fuse_exit(void) 1237 { 1238 printk(KERN_DEBUG "fuse exit\n"); 1239 1240 fuse_ctl_cleanup(); 1241 fuse_sysfs_cleanup(); 1242 fuse_fs_cleanup(); 1243 fuse_dev_cleanup(); 1244 } 1245 1246 module_init(fuse_init); 1247 module_exit(fuse_exit); 1248