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_evict_inode(struct inode *inode) 126 { 127 truncate_inode_pages(&inode->i_data, 0); 128 end_writeback(inode); 129 if (inode->i_sb->s_flags & MS_ACTIVE) { 130 struct fuse_conn *fc = get_fuse_conn(inode); 131 struct fuse_inode *fi = get_fuse_inode(inode); 132 fuse_send_forget(fc, fi->forget_req, fi->nodeid, fi->nlookup); 133 fi->forget_req = NULL; 134 } 135 } 136 137 static int fuse_remount_fs(struct super_block *sb, int *flags, char *data) 138 { 139 if (*flags & MS_MANDLOCK) 140 return -EINVAL; 141 142 return 0; 143 } 144 145 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr, 146 u64 attr_valid) 147 { 148 struct fuse_conn *fc = get_fuse_conn(inode); 149 struct fuse_inode *fi = get_fuse_inode(inode); 150 151 fi->attr_version = ++fc->attr_version; 152 fi->i_time = attr_valid; 153 154 inode->i_ino = attr->ino; 155 inode->i_mode = (inode->i_mode & S_IFMT) | (attr->mode & 07777); 156 inode->i_nlink = attr->nlink; 157 inode->i_uid = attr->uid; 158 inode->i_gid = attr->gid; 159 inode->i_blocks = attr->blocks; 160 inode->i_atime.tv_sec = attr->atime; 161 inode->i_atime.tv_nsec = attr->atimensec; 162 inode->i_mtime.tv_sec = attr->mtime; 163 inode->i_mtime.tv_nsec = attr->mtimensec; 164 inode->i_ctime.tv_sec = attr->ctime; 165 inode->i_ctime.tv_nsec = attr->ctimensec; 166 167 if (attr->blksize != 0) 168 inode->i_blkbits = ilog2(attr->blksize); 169 else 170 inode->i_blkbits = inode->i_sb->s_blocksize_bits; 171 172 /* 173 * Don't set the sticky bit in i_mode, unless we want the VFS 174 * to check permissions. This prevents failures due to the 175 * check in may_delete(). 176 */ 177 fi->orig_i_mode = inode->i_mode; 178 if (!(fc->flags & FUSE_DEFAULT_PERMISSIONS)) 179 inode->i_mode &= ~S_ISVTX; 180 } 181 182 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr, 183 u64 attr_valid, u64 attr_version) 184 { 185 struct fuse_conn *fc = get_fuse_conn(inode); 186 struct fuse_inode *fi = get_fuse_inode(inode); 187 loff_t oldsize; 188 189 spin_lock(&fc->lock); 190 if (attr_version != 0 && fi->attr_version > attr_version) { 191 spin_unlock(&fc->lock); 192 return; 193 } 194 195 fuse_change_attributes_common(inode, attr, attr_valid); 196 197 oldsize = inode->i_size; 198 i_size_write(inode, attr->size); 199 spin_unlock(&fc->lock); 200 201 if (S_ISREG(inode->i_mode) && oldsize != attr->size) { 202 truncate_pagecache(inode, oldsize, attr->size); 203 invalidate_inode_pages2(inode->i_mapping); 204 } 205 } 206 207 static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr) 208 { 209 inode->i_mode = attr->mode & S_IFMT; 210 inode->i_size = attr->size; 211 if (S_ISREG(inode->i_mode)) { 212 fuse_init_common(inode); 213 fuse_init_file_inode(inode); 214 } else if (S_ISDIR(inode->i_mode)) 215 fuse_init_dir(inode); 216 else if (S_ISLNK(inode->i_mode)) 217 fuse_init_symlink(inode); 218 else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) || 219 S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) { 220 fuse_init_common(inode); 221 init_special_inode(inode, inode->i_mode, 222 new_decode_dev(attr->rdev)); 223 } else 224 BUG(); 225 } 226 227 int fuse_inode_eq(struct inode *inode, void *_nodeidp) 228 { 229 u64 nodeid = *(u64 *) _nodeidp; 230 if (get_node_id(inode) == nodeid) 231 return 1; 232 else 233 return 0; 234 } 235 236 static int fuse_inode_set(struct inode *inode, void *_nodeidp) 237 { 238 u64 nodeid = *(u64 *) _nodeidp; 239 get_fuse_inode(inode)->nodeid = nodeid; 240 return 0; 241 } 242 243 struct inode *fuse_iget(struct super_block *sb, u64 nodeid, 244 int generation, struct fuse_attr *attr, 245 u64 attr_valid, u64 attr_version) 246 { 247 struct inode *inode; 248 struct fuse_inode *fi; 249 struct fuse_conn *fc = get_fuse_conn_super(sb); 250 251 retry: 252 inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid); 253 if (!inode) 254 return NULL; 255 256 if ((inode->i_state & I_NEW)) { 257 inode->i_flags |= S_NOATIME|S_NOCMTIME; 258 inode->i_generation = generation; 259 inode->i_data.backing_dev_info = &fc->bdi; 260 fuse_init_inode(inode, attr); 261 unlock_new_inode(inode); 262 } else if ((inode->i_mode ^ attr->mode) & S_IFMT) { 263 /* Inode has changed type, any I/O on the old should fail */ 264 make_bad_inode(inode); 265 iput(inode); 266 goto retry; 267 } 268 269 fi = get_fuse_inode(inode); 270 spin_lock(&fc->lock); 271 fi->nlookup++; 272 spin_unlock(&fc->lock); 273 fuse_change_attributes(inode, attr, attr_valid, attr_version); 274 275 return inode; 276 } 277 278 int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid, 279 loff_t offset, loff_t len) 280 { 281 struct inode *inode; 282 pgoff_t pg_start; 283 pgoff_t pg_end; 284 285 inode = ilookup5(sb, nodeid, fuse_inode_eq, &nodeid); 286 if (!inode) 287 return -ENOENT; 288 289 fuse_invalidate_attr(inode); 290 if (offset >= 0) { 291 pg_start = offset >> PAGE_CACHE_SHIFT; 292 if (len <= 0) 293 pg_end = -1; 294 else 295 pg_end = (offset + len - 1) >> PAGE_CACHE_SHIFT; 296 invalidate_inode_pages2_range(inode->i_mapping, 297 pg_start, pg_end); 298 } 299 iput(inode); 300 return 0; 301 } 302 303 static void fuse_umount_begin(struct super_block *sb) 304 { 305 fuse_abort_conn(get_fuse_conn_super(sb)); 306 } 307 308 static void fuse_send_destroy(struct fuse_conn *fc) 309 { 310 struct fuse_req *req = fc->destroy_req; 311 if (req && fc->conn_init) { 312 fc->destroy_req = NULL; 313 req->in.h.opcode = FUSE_DESTROY; 314 req->force = 1; 315 fuse_request_send(fc, req); 316 fuse_put_request(fc, req); 317 } 318 } 319 320 static void fuse_bdi_destroy(struct fuse_conn *fc) 321 { 322 if (fc->bdi_initialized) 323 bdi_destroy(&fc->bdi); 324 } 325 326 void fuse_conn_kill(struct fuse_conn *fc) 327 { 328 spin_lock(&fc->lock); 329 fc->connected = 0; 330 fc->blocked = 0; 331 spin_unlock(&fc->lock); 332 /* Flush all readers on this fs */ 333 kill_fasync(&fc->fasync, SIGIO, POLL_IN); 334 wake_up_all(&fc->waitq); 335 wake_up_all(&fc->blocked_waitq); 336 wake_up_all(&fc->reserved_req_waitq); 337 mutex_lock(&fuse_mutex); 338 list_del(&fc->entry); 339 fuse_ctl_remove_conn(fc); 340 mutex_unlock(&fuse_mutex); 341 fuse_bdi_destroy(fc); 342 } 343 EXPORT_SYMBOL_GPL(fuse_conn_kill); 344 345 static void fuse_put_super(struct super_block *sb) 346 { 347 struct fuse_conn *fc = get_fuse_conn_super(sb); 348 349 fuse_send_destroy(fc); 350 fuse_conn_kill(fc); 351 fuse_conn_put(fc); 352 } 353 354 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr) 355 { 356 stbuf->f_type = FUSE_SUPER_MAGIC; 357 stbuf->f_bsize = attr->bsize; 358 stbuf->f_frsize = attr->frsize; 359 stbuf->f_blocks = attr->blocks; 360 stbuf->f_bfree = attr->bfree; 361 stbuf->f_bavail = attr->bavail; 362 stbuf->f_files = attr->files; 363 stbuf->f_ffree = attr->ffree; 364 stbuf->f_namelen = attr->namelen; 365 /* fsid is left zero */ 366 } 367 368 static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf) 369 { 370 struct super_block *sb = dentry->d_sb; 371 struct fuse_conn *fc = get_fuse_conn_super(sb); 372 struct fuse_req *req; 373 struct fuse_statfs_out outarg; 374 int err; 375 376 if (!fuse_allow_task(fc, current)) { 377 buf->f_type = FUSE_SUPER_MAGIC; 378 return 0; 379 } 380 381 req = fuse_get_req(fc); 382 if (IS_ERR(req)) 383 return PTR_ERR(req); 384 385 memset(&outarg, 0, sizeof(outarg)); 386 req->in.numargs = 0; 387 req->in.h.opcode = FUSE_STATFS; 388 req->in.h.nodeid = get_node_id(dentry->d_inode); 389 req->out.numargs = 1; 390 req->out.args[0].size = 391 fc->minor < 4 ? FUSE_COMPAT_STATFS_SIZE : sizeof(outarg); 392 req->out.args[0].value = &outarg; 393 fuse_request_send(fc, req); 394 err = req->out.h.error; 395 if (!err) 396 convert_fuse_statfs(buf, &outarg.st); 397 fuse_put_request(fc, req); 398 return err; 399 } 400 401 enum { 402 OPT_FD, 403 OPT_ROOTMODE, 404 OPT_USER_ID, 405 OPT_GROUP_ID, 406 OPT_DEFAULT_PERMISSIONS, 407 OPT_ALLOW_OTHER, 408 OPT_MAX_READ, 409 OPT_BLKSIZE, 410 OPT_ERR 411 }; 412 413 static const match_table_t tokens = { 414 {OPT_FD, "fd=%u"}, 415 {OPT_ROOTMODE, "rootmode=%o"}, 416 {OPT_USER_ID, "user_id=%u"}, 417 {OPT_GROUP_ID, "group_id=%u"}, 418 {OPT_DEFAULT_PERMISSIONS, "default_permissions"}, 419 {OPT_ALLOW_OTHER, "allow_other"}, 420 {OPT_MAX_READ, "max_read=%u"}, 421 {OPT_BLKSIZE, "blksize=%u"}, 422 {OPT_ERR, NULL} 423 }; 424 425 static int parse_fuse_opt(char *opt, struct fuse_mount_data *d, int is_bdev) 426 { 427 char *p; 428 memset(d, 0, sizeof(struct fuse_mount_data)); 429 d->max_read = ~0; 430 d->blksize = FUSE_DEFAULT_BLKSIZE; 431 432 while ((p = strsep(&opt, ",")) != NULL) { 433 int token; 434 int value; 435 substring_t args[MAX_OPT_ARGS]; 436 if (!*p) 437 continue; 438 439 token = match_token(p, tokens, args); 440 switch (token) { 441 case OPT_FD: 442 if (match_int(&args[0], &value)) 443 return 0; 444 d->fd = value; 445 d->fd_present = 1; 446 break; 447 448 case OPT_ROOTMODE: 449 if (match_octal(&args[0], &value)) 450 return 0; 451 if (!fuse_valid_type(value)) 452 return 0; 453 d->rootmode = value; 454 d->rootmode_present = 1; 455 break; 456 457 case OPT_USER_ID: 458 if (match_int(&args[0], &value)) 459 return 0; 460 d->user_id = value; 461 d->user_id_present = 1; 462 break; 463 464 case OPT_GROUP_ID: 465 if (match_int(&args[0], &value)) 466 return 0; 467 d->group_id = value; 468 d->group_id_present = 1; 469 break; 470 471 case OPT_DEFAULT_PERMISSIONS: 472 d->flags |= FUSE_DEFAULT_PERMISSIONS; 473 break; 474 475 case OPT_ALLOW_OTHER: 476 d->flags |= FUSE_ALLOW_OTHER; 477 break; 478 479 case OPT_MAX_READ: 480 if (match_int(&args[0], &value)) 481 return 0; 482 d->max_read = value; 483 break; 484 485 case OPT_BLKSIZE: 486 if (!is_bdev || match_int(&args[0], &value)) 487 return 0; 488 d->blksize = value; 489 break; 490 491 default: 492 return 0; 493 } 494 } 495 496 if (!d->fd_present || !d->rootmode_present || 497 !d->user_id_present || !d->group_id_present) 498 return 0; 499 500 return 1; 501 } 502 503 static int fuse_show_options(struct seq_file *m, struct vfsmount *mnt) 504 { 505 struct fuse_conn *fc = get_fuse_conn_super(mnt->mnt_sb); 506 507 seq_printf(m, ",user_id=%u", fc->user_id); 508 seq_printf(m, ",group_id=%u", fc->group_id); 509 if (fc->flags & FUSE_DEFAULT_PERMISSIONS) 510 seq_puts(m, ",default_permissions"); 511 if (fc->flags & FUSE_ALLOW_OTHER) 512 seq_puts(m, ",allow_other"); 513 if (fc->max_read != ~0) 514 seq_printf(m, ",max_read=%u", fc->max_read); 515 if (mnt->mnt_sb->s_bdev && 516 mnt->mnt_sb->s_blocksize != FUSE_DEFAULT_BLKSIZE) 517 seq_printf(m, ",blksize=%lu", mnt->mnt_sb->s_blocksize); 518 return 0; 519 } 520 521 void fuse_conn_init(struct fuse_conn *fc) 522 { 523 memset(fc, 0, sizeof(*fc)); 524 spin_lock_init(&fc->lock); 525 mutex_init(&fc->inst_mutex); 526 init_rwsem(&fc->killsb); 527 atomic_set(&fc->count, 1); 528 init_waitqueue_head(&fc->waitq); 529 init_waitqueue_head(&fc->blocked_waitq); 530 init_waitqueue_head(&fc->reserved_req_waitq); 531 INIT_LIST_HEAD(&fc->pending); 532 INIT_LIST_HEAD(&fc->processing); 533 INIT_LIST_HEAD(&fc->io); 534 INIT_LIST_HEAD(&fc->interrupts); 535 INIT_LIST_HEAD(&fc->bg_queue); 536 INIT_LIST_HEAD(&fc->entry); 537 atomic_set(&fc->num_waiting, 0); 538 fc->max_background = FUSE_DEFAULT_MAX_BACKGROUND; 539 fc->congestion_threshold = FUSE_DEFAULT_CONGESTION_THRESHOLD; 540 fc->khctr = 0; 541 fc->polled_files = RB_ROOT; 542 fc->reqctr = 0; 543 fc->blocked = 1; 544 fc->attr_version = 1; 545 get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key)); 546 } 547 EXPORT_SYMBOL_GPL(fuse_conn_init); 548 549 void fuse_conn_put(struct fuse_conn *fc) 550 { 551 if (atomic_dec_and_test(&fc->count)) { 552 if (fc->destroy_req) 553 fuse_request_free(fc->destroy_req); 554 mutex_destroy(&fc->inst_mutex); 555 fc->release(fc); 556 } 557 } 558 EXPORT_SYMBOL_GPL(fuse_conn_put); 559 560 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc) 561 { 562 atomic_inc(&fc->count); 563 return fc; 564 } 565 EXPORT_SYMBOL_GPL(fuse_conn_get); 566 567 static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned mode) 568 { 569 struct fuse_attr attr; 570 memset(&attr, 0, sizeof(attr)); 571 572 attr.mode = mode; 573 attr.ino = FUSE_ROOT_ID; 574 attr.nlink = 1; 575 return fuse_iget(sb, 1, 0, &attr, 0, 0); 576 } 577 578 struct fuse_inode_handle { 579 u64 nodeid; 580 u32 generation; 581 }; 582 583 static struct dentry *fuse_get_dentry(struct super_block *sb, 584 struct fuse_inode_handle *handle) 585 { 586 struct fuse_conn *fc = get_fuse_conn_super(sb); 587 struct inode *inode; 588 struct dentry *entry; 589 int err = -ESTALE; 590 591 if (handle->nodeid == 0) 592 goto out_err; 593 594 inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid); 595 if (!inode) { 596 struct fuse_entry_out outarg; 597 struct qstr name; 598 599 if (!fc->export_support) 600 goto out_err; 601 602 name.len = 1; 603 name.name = "."; 604 err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg, 605 &inode); 606 if (err && err != -ENOENT) 607 goto out_err; 608 if (err || !inode) { 609 err = -ESTALE; 610 goto out_err; 611 } 612 err = -EIO; 613 if (get_node_id(inode) != handle->nodeid) 614 goto out_iput; 615 } 616 err = -ESTALE; 617 if (inode->i_generation != handle->generation) 618 goto out_iput; 619 620 entry = d_obtain_alias(inode); 621 if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID) { 622 entry->d_op = &fuse_dentry_operations; 623 fuse_invalidate_entry_cache(entry); 624 } 625 626 return entry; 627 628 out_iput: 629 iput(inode); 630 out_err: 631 return ERR_PTR(err); 632 } 633 634 static int fuse_encode_fh(struct dentry *dentry, u32 *fh, int *max_len, 635 int connectable) 636 { 637 struct inode *inode = dentry->d_inode; 638 bool encode_parent = connectable && !S_ISDIR(inode->i_mode); 639 int len = encode_parent ? 6 : 3; 640 u64 nodeid; 641 u32 generation; 642 643 if (*max_len < len) 644 return 255; 645 646 nodeid = get_fuse_inode(inode)->nodeid; 647 generation = inode->i_generation; 648 649 fh[0] = (u32)(nodeid >> 32); 650 fh[1] = (u32)(nodeid & 0xffffffff); 651 fh[2] = generation; 652 653 if (encode_parent) { 654 struct inode *parent; 655 656 spin_lock(&dentry->d_lock); 657 parent = dentry->d_parent->d_inode; 658 nodeid = get_fuse_inode(parent)->nodeid; 659 generation = parent->i_generation; 660 spin_unlock(&dentry->d_lock); 661 662 fh[3] = (u32)(nodeid >> 32); 663 fh[4] = (u32)(nodeid & 0xffffffff); 664 fh[5] = generation; 665 } 666 667 *max_len = len; 668 return encode_parent ? 0x82 : 0x81; 669 } 670 671 static struct dentry *fuse_fh_to_dentry(struct super_block *sb, 672 struct fid *fid, int fh_len, int fh_type) 673 { 674 struct fuse_inode_handle handle; 675 676 if ((fh_type != 0x81 && fh_type != 0x82) || fh_len < 3) 677 return NULL; 678 679 handle.nodeid = (u64) fid->raw[0] << 32; 680 handle.nodeid |= (u64) fid->raw[1]; 681 handle.generation = fid->raw[2]; 682 return fuse_get_dentry(sb, &handle); 683 } 684 685 static struct dentry *fuse_fh_to_parent(struct super_block *sb, 686 struct fid *fid, int fh_len, int fh_type) 687 { 688 struct fuse_inode_handle parent; 689 690 if (fh_type != 0x82 || fh_len < 6) 691 return NULL; 692 693 parent.nodeid = (u64) fid->raw[3] << 32; 694 parent.nodeid |= (u64) fid->raw[4]; 695 parent.generation = fid->raw[5]; 696 return fuse_get_dentry(sb, &parent); 697 } 698 699 static struct dentry *fuse_get_parent(struct dentry *child) 700 { 701 struct inode *child_inode = child->d_inode; 702 struct fuse_conn *fc = get_fuse_conn(child_inode); 703 struct inode *inode; 704 struct dentry *parent; 705 struct fuse_entry_out outarg; 706 struct qstr name; 707 int err; 708 709 if (!fc->export_support) 710 return ERR_PTR(-ESTALE); 711 712 name.len = 2; 713 name.name = ".."; 714 err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode), 715 &name, &outarg, &inode); 716 if (err) { 717 if (err == -ENOENT) 718 return ERR_PTR(-ESTALE); 719 return ERR_PTR(err); 720 } 721 722 parent = d_obtain_alias(inode); 723 if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID) { 724 parent->d_op = &fuse_dentry_operations; 725 fuse_invalidate_entry_cache(parent); 726 } 727 728 return parent; 729 } 730 731 static const struct export_operations fuse_export_operations = { 732 .fh_to_dentry = fuse_fh_to_dentry, 733 .fh_to_parent = fuse_fh_to_parent, 734 .encode_fh = fuse_encode_fh, 735 .get_parent = fuse_get_parent, 736 }; 737 738 static const struct super_operations fuse_super_operations = { 739 .alloc_inode = fuse_alloc_inode, 740 .destroy_inode = fuse_destroy_inode, 741 .evict_inode = fuse_evict_inode, 742 .drop_inode = generic_delete_inode, 743 .remount_fs = fuse_remount_fs, 744 .put_super = fuse_put_super, 745 .umount_begin = fuse_umount_begin, 746 .statfs = fuse_statfs, 747 .show_options = fuse_show_options, 748 }; 749 750 static void sanitize_global_limit(unsigned *limit) 751 { 752 if (*limit == 0) 753 *limit = ((num_physpages << PAGE_SHIFT) >> 13) / 754 sizeof(struct fuse_req); 755 756 if (*limit >= 1 << 16) 757 *limit = (1 << 16) - 1; 758 } 759 760 static int set_global_limit(const char *val, struct kernel_param *kp) 761 { 762 int rv; 763 764 rv = param_set_uint(val, kp); 765 if (rv) 766 return rv; 767 768 sanitize_global_limit((unsigned *)kp->arg); 769 770 return 0; 771 } 772 773 static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg) 774 { 775 int cap_sys_admin = capable(CAP_SYS_ADMIN); 776 777 if (arg->minor < 13) 778 return; 779 780 sanitize_global_limit(&max_user_bgreq); 781 sanitize_global_limit(&max_user_congthresh); 782 783 if (arg->max_background) { 784 fc->max_background = arg->max_background; 785 786 if (!cap_sys_admin && fc->max_background > max_user_bgreq) 787 fc->max_background = max_user_bgreq; 788 } 789 if (arg->congestion_threshold) { 790 fc->congestion_threshold = arg->congestion_threshold; 791 792 if (!cap_sys_admin && 793 fc->congestion_threshold > max_user_congthresh) 794 fc->congestion_threshold = max_user_congthresh; 795 } 796 } 797 798 static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req) 799 { 800 struct fuse_init_out *arg = &req->misc.init_out; 801 802 if (req->out.h.error || arg->major != FUSE_KERNEL_VERSION) 803 fc->conn_error = 1; 804 else { 805 unsigned long ra_pages; 806 807 process_init_limits(fc, arg); 808 809 if (arg->minor >= 6) { 810 ra_pages = arg->max_readahead / PAGE_CACHE_SIZE; 811 if (arg->flags & FUSE_ASYNC_READ) 812 fc->async_read = 1; 813 if (!(arg->flags & FUSE_POSIX_LOCKS)) 814 fc->no_lock = 1; 815 if (arg->flags & FUSE_ATOMIC_O_TRUNC) 816 fc->atomic_o_trunc = 1; 817 if (arg->minor >= 9) { 818 /* LOOKUP has dependency on proto version */ 819 if (arg->flags & FUSE_EXPORT_SUPPORT) 820 fc->export_support = 1; 821 } 822 if (arg->flags & FUSE_BIG_WRITES) 823 fc->big_writes = 1; 824 if (arg->flags & FUSE_DONT_MASK) 825 fc->dont_mask = 1; 826 } else { 827 ra_pages = fc->max_read / PAGE_CACHE_SIZE; 828 fc->no_lock = 1; 829 } 830 831 fc->bdi.ra_pages = min(fc->bdi.ra_pages, ra_pages); 832 fc->minor = arg->minor; 833 fc->max_write = arg->minor < 5 ? 4096 : arg->max_write; 834 fc->max_write = max_t(unsigned, 4096, fc->max_write); 835 fc->conn_init = 1; 836 } 837 fc->blocked = 0; 838 wake_up_all(&fc->blocked_waitq); 839 } 840 841 static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req) 842 { 843 struct fuse_init_in *arg = &req->misc.init_in; 844 845 arg->major = FUSE_KERNEL_VERSION; 846 arg->minor = FUSE_KERNEL_MINOR_VERSION; 847 arg->max_readahead = fc->bdi.ra_pages * PAGE_CACHE_SIZE; 848 arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC | 849 FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK; 850 req->in.h.opcode = FUSE_INIT; 851 req->in.numargs = 1; 852 req->in.args[0].size = sizeof(*arg); 853 req->in.args[0].value = arg; 854 req->out.numargs = 1; 855 /* Variable length argument used for backward compatibility 856 with interface version < 7.5. Rest of init_out is zeroed 857 by do_get_request(), so a short reply is not a problem */ 858 req->out.argvar = 1; 859 req->out.args[0].size = sizeof(struct fuse_init_out); 860 req->out.args[0].value = &req->misc.init_out; 861 req->end = process_init_reply; 862 fuse_request_send_background(fc, req); 863 } 864 865 static void fuse_free_conn(struct fuse_conn *fc) 866 { 867 kfree(fc); 868 } 869 870 static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb) 871 { 872 int err; 873 874 fc->bdi.name = "fuse"; 875 fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE; 876 fc->bdi.unplug_io_fn = default_unplug_io_fn; 877 /* fuse does it's own writeback accounting */ 878 fc->bdi.capabilities = BDI_CAP_NO_ACCT_WB; 879 880 err = bdi_init(&fc->bdi); 881 if (err) 882 return err; 883 884 fc->bdi_initialized = 1; 885 886 if (sb->s_bdev) { 887 err = bdi_register(&fc->bdi, NULL, "%u:%u-fuseblk", 888 MAJOR(fc->dev), MINOR(fc->dev)); 889 } else { 890 err = bdi_register_dev(&fc->bdi, fc->dev); 891 } 892 893 if (err) 894 return err; 895 896 /* 897 * For a single fuse filesystem use max 1% of dirty + 898 * writeback threshold. 899 * 900 * This gives about 1M of write buffer for memory maps on a 901 * machine with 1G and 10% dirty_ratio, which should be more 902 * than enough. 903 * 904 * Privileged users can raise it by writing to 905 * 906 * /sys/class/bdi/<bdi>/max_ratio 907 */ 908 bdi_set_max_ratio(&fc->bdi, 1); 909 910 return 0; 911 } 912 913 static int fuse_fill_super(struct super_block *sb, void *data, int silent) 914 { 915 struct fuse_conn *fc; 916 struct inode *root; 917 struct fuse_mount_data d; 918 struct file *file; 919 struct dentry *root_dentry; 920 struct fuse_req *init_req; 921 int err; 922 int is_bdev = sb->s_bdev != NULL; 923 924 err = -EINVAL; 925 if (sb->s_flags & MS_MANDLOCK) 926 goto err; 927 928 if (!parse_fuse_opt((char *) data, &d, is_bdev)) 929 goto err; 930 931 if (is_bdev) { 932 #ifdef CONFIG_BLOCK 933 err = -EINVAL; 934 if (!sb_set_blocksize(sb, d.blksize)) 935 goto err; 936 #endif 937 } else { 938 sb->s_blocksize = PAGE_CACHE_SIZE; 939 sb->s_blocksize_bits = PAGE_CACHE_SHIFT; 940 } 941 sb->s_magic = FUSE_SUPER_MAGIC; 942 sb->s_op = &fuse_super_operations; 943 sb->s_maxbytes = MAX_LFS_FILESIZE; 944 sb->s_export_op = &fuse_export_operations; 945 946 file = fget(d.fd); 947 err = -EINVAL; 948 if (!file) 949 goto err; 950 951 if (file->f_op != &fuse_dev_operations) 952 goto err_fput; 953 954 fc = kmalloc(sizeof(*fc), GFP_KERNEL); 955 err = -ENOMEM; 956 if (!fc) 957 goto err_fput; 958 959 fuse_conn_init(fc); 960 961 fc->dev = sb->s_dev; 962 fc->sb = sb; 963 err = fuse_bdi_init(fc, sb); 964 if (err) 965 goto err_put_conn; 966 967 sb->s_bdi = &fc->bdi; 968 969 /* Handle umasking inside the fuse code */ 970 if (sb->s_flags & MS_POSIXACL) 971 fc->dont_mask = 1; 972 sb->s_flags |= MS_POSIXACL; 973 974 fc->release = fuse_free_conn; 975 fc->flags = d.flags; 976 fc->user_id = d.user_id; 977 fc->group_id = d.group_id; 978 fc->max_read = max_t(unsigned, 4096, d.max_read); 979 980 /* Used by get_root_inode() */ 981 sb->s_fs_info = fc; 982 983 err = -ENOMEM; 984 root = fuse_get_root_inode(sb, d.rootmode); 985 if (!root) 986 goto err_put_conn; 987 988 root_dentry = d_alloc_root(root); 989 if (!root_dentry) { 990 iput(root); 991 goto err_put_conn; 992 } 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