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 #ifndef _FS_FUSE_I_H 10 #define _FS_FUSE_I_H 11 12 #include <linux/fuse.h> 13 #include <linux/fs.h> 14 #include <linux/mount.h> 15 #include <linux/wait.h> 16 #include <linux/list.h> 17 #include <linux/spinlock.h> 18 #include <linux/mm.h> 19 #include <linux/backing-dev.h> 20 #include <linux/mutex.h> 21 #include <linux/rwsem.h> 22 #include <linux/rbtree.h> 23 #include <linux/poll.h> 24 #include <linux/workqueue.h> 25 26 /** Max number of pages that can be used in a single read request */ 27 #define FUSE_MAX_PAGES_PER_REQ 32 28 29 /** Bias for fi->writectr, meaning new writepages must not be sent */ 30 #define FUSE_NOWRITE INT_MIN 31 32 /** It could be as large as PATH_MAX, but would that have any uses? */ 33 #define FUSE_NAME_MAX 1024 34 35 /** Number of dentries for each connection in the control filesystem */ 36 #define FUSE_CTL_NUM_DENTRIES 5 37 38 /** If the FUSE_DEFAULT_PERMISSIONS flag is given, the filesystem 39 module will check permissions based on the file mode. Otherwise no 40 permission checking is done in the kernel */ 41 #define FUSE_DEFAULT_PERMISSIONS (1 << 0) 42 43 /** If the FUSE_ALLOW_OTHER flag is given, then not only the user 44 doing the mount will be allowed to access the filesystem */ 45 #define FUSE_ALLOW_OTHER (1 << 1) 46 47 /** List of active connections */ 48 extern struct list_head fuse_conn_list; 49 50 /** Global mutex protecting fuse_conn_list and the control filesystem */ 51 extern struct mutex fuse_mutex; 52 53 /** Module parameters */ 54 extern unsigned max_user_bgreq; 55 extern unsigned max_user_congthresh; 56 57 /* One forget request */ 58 struct fuse_forget_link { 59 struct fuse_forget_one forget_one; 60 struct fuse_forget_link *next; 61 }; 62 63 /** FUSE inode */ 64 struct fuse_inode { 65 /** Inode data */ 66 struct inode inode; 67 68 /** Unique ID, which identifies the inode between userspace 69 * and kernel */ 70 u64 nodeid; 71 72 /** Number of lookups on this inode */ 73 u64 nlookup; 74 75 /** The request used for sending the FORGET message */ 76 struct fuse_forget_link *forget; 77 78 /** Time in jiffies until the file attributes are valid */ 79 u64 i_time; 80 81 /** The sticky bit in inode->i_mode may have been removed, so 82 preserve the original mode */ 83 umode_t orig_i_mode; 84 85 /** Version of last attribute change */ 86 u64 attr_version; 87 88 /** Files usable in writepage. Protected by fc->lock */ 89 struct list_head write_files; 90 91 /** Writepages pending on truncate or fsync */ 92 struct list_head queued_writes; 93 94 /** Number of sent writes, a negative bias (FUSE_NOWRITE) 95 * means more writes are blocked */ 96 int writectr; 97 98 /** Waitq for writepage completion */ 99 wait_queue_head_t page_waitq; 100 101 /** List of writepage requestst (pending or sent) */ 102 struct list_head writepages; 103 }; 104 105 struct fuse_conn; 106 107 /** FUSE specific file data */ 108 struct fuse_file { 109 /** Fuse connection for this file */ 110 struct fuse_conn *fc; 111 112 /** Request reserved for flush and release */ 113 struct fuse_req *reserved_req; 114 115 /** Kernel file handle guaranteed to be unique */ 116 u64 kh; 117 118 /** File handle used by userspace */ 119 u64 fh; 120 121 /** Node id of this file */ 122 u64 nodeid; 123 124 /** Refcount */ 125 atomic_t count; 126 127 /** FOPEN_* flags returned by open */ 128 u32 open_flags; 129 130 /** Entry on inode's write_files list */ 131 struct list_head write_entry; 132 133 /** RB node to be linked on fuse_conn->polled_files */ 134 struct rb_node polled_node; 135 136 /** Wait queue head for poll */ 137 wait_queue_head_t poll_wait; 138 139 /** Has flock been performed on this file? */ 140 bool flock:1; 141 }; 142 143 /** One input argument of a request */ 144 struct fuse_in_arg { 145 unsigned size; 146 const void *value; 147 }; 148 149 /** The request input */ 150 struct fuse_in { 151 /** The request header */ 152 struct fuse_in_header h; 153 154 /** True if the data for the last argument is in req->pages */ 155 unsigned argpages:1; 156 157 /** Number of arguments */ 158 unsigned numargs; 159 160 /** Array of arguments */ 161 struct fuse_in_arg args[3]; 162 }; 163 164 /** One output argument of a request */ 165 struct fuse_arg { 166 unsigned size; 167 void *value; 168 }; 169 170 /** The request output */ 171 struct fuse_out { 172 /** Header returned from userspace */ 173 struct fuse_out_header h; 174 175 /* 176 * The following bitfields are not changed during the request 177 * processing 178 */ 179 180 /** Last argument is variable length (can be shorter than 181 arg->size) */ 182 unsigned argvar:1; 183 184 /** Last argument is a list of pages to copy data to */ 185 unsigned argpages:1; 186 187 /** Zero partially or not copied pages */ 188 unsigned page_zeroing:1; 189 190 /** Pages may be replaced with new ones */ 191 unsigned page_replace:1; 192 193 /** Number or arguments */ 194 unsigned numargs; 195 196 /** Array of arguments */ 197 struct fuse_arg args[3]; 198 }; 199 200 /** The request state */ 201 enum fuse_req_state { 202 FUSE_REQ_INIT = 0, 203 FUSE_REQ_PENDING, 204 FUSE_REQ_READING, 205 FUSE_REQ_SENT, 206 FUSE_REQ_WRITING, 207 FUSE_REQ_FINISHED 208 }; 209 210 /** 211 * A request to the client 212 */ 213 struct fuse_req { 214 /** This can be on either pending processing or io lists in 215 fuse_conn */ 216 struct list_head list; 217 218 /** Entry on the interrupts list */ 219 struct list_head intr_entry; 220 221 /** refcount */ 222 atomic_t count; 223 224 /** Unique ID for the interrupt request */ 225 u64 intr_unique; 226 227 /* 228 * The following bitfields are either set once before the 229 * request is queued or setting/clearing them is protected by 230 * fuse_conn->lock 231 */ 232 233 /** True if the request has reply */ 234 unsigned isreply:1; 235 236 /** Force sending of the request even if interrupted */ 237 unsigned force:1; 238 239 /** The request was aborted */ 240 unsigned aborted:1; 241 242 /** Request is sent in the background */ 243 unsigned background:1; 244 245 /** The request has been interrupted */ 246 unsigned interrupted:1; 247 248 /** Data is being copied to/from the request */ 249 unsigned locked:1; 250 251 /** Request is counted as "waiting" */ 252 unsigned waiting:1; 253 254 /** State of the request */ 255 enum fuse_req_state state; 256 257 /** The request input */ 258 struct fuse_in in; 259 260 /** The request output */ 261 struct fuse_out out; 262 263 /** Used to wake up the task waiting for completion of request*/ 264 wait_queue_head_t waitq; 265 266 /** Data for asynchronous requests */ 267 union { 268 struct { 269 union { 270 struct fuse_release_in in; 271 struct work_struct work; 272 }; 273 struct path path; 274 } release; 275 struct fuse_init_in init_in; 276 struct fuse_init_out init_out; 277 struct cuse_init_in cuse_init_in; 278 struct { 279 struct fuse_read_in in; 280 u64 attr_ver; 281 } read; 282 struct { 283 struct fuse_write_in in; 284 struct fuse_write_out out; 285 } write; 286 struct fuse_notify_retrieve_in retrieve_in; 287 struct fuse_lk_in lk_in; 288 } misc; 289 290 /** page vector */ 291 struct page *pages[FUSE_MAX_PAGES_PER_REQ]; 292 293 /** number of pages in vector */ 294 unsigned num_pages; 295 296 /** offset of data on first page */ 297 unsigned page_offset; 298 299 /** File used in the request (or NULL) */ 300 struct fuse_file *ff; 301 302 /** Inode used in the request or NULL */ 303 struct inode *inode; 304 305 /** Link on fi->writepages */ 306 struct list_head writepages_entry; 307 308 /** Request completion callback */ 309 void (*end)(struct fuse_conn *, struct fuse_req *); 310 311 /** Request is stolen from fuse_file->reserved_req */ 312 struct file *stolen_file; 313 }; 314 315 /** 316 * A Fuse connection. 317 * 318 * This structure is created, when the filesystem is mounted, and is 319 * destroyed, when the client device is closed and the filesystem is 320 * unmounted. 321 */ 322 struct fuse_conn { 323 /** Lock protecting accessess to members of this structure */ 324 spinlock_t lock; 325 326 /** Mutex protecting against directory alias creation */ 327 struct mutex inst_mutex; 328 329 /** Refcount */ 330 atomic_t count; 331 332 /** The user id for this mount */ 333 uid_t user_id; 334 335 /** The group id for this mount */ 336 gid_t group_id; 337 338 /** The fuse mount flags for this mount */ 339 unsigned flags; 340 341 /** Maximum read size */ 342 unsigned max_read; 343 344 /** Maximum write size */ 345 unsigned max_write; 346 347 /** Readers of the connection are waiting on this */ 348 wait_queue_head_t waitq; 349 350 /** The list of pending requests */ 351 struct list_head pending; 352 353 /** The list of requests being processed */ 354 struct list_head processing; 355 356 /** The list of requests under I/O */ 357 struct list_head io; 358 359 /** The next unique kernel file handle */ 360 u64 khctr; 361 362 /** rbtree of fuse_files waiting for poll events indexed by ph */ 363 struct rb_root polled_files; 364 365 /** Maximum number of outstanding background requests */ 366 unsigned max_background; 367 368 /** Number of background requests at which congestion starts */ 369 unsigned congestion_threshold; 370 371 /** Number of requests currently in the background */ 372 unsigned num_background; 373 374 /** Number of background requests currently queued for userspace */ 375 unsigned active_background; 376 377 /** The list of background requests set aside for later queuing */ 378 struct list_head bg_queue; 379 380 /** Pending interrupts */ 381 struct list_head interrupts; 382 383 /** Queue of pending forgets */ 384 struct fuse_forget_link forget_list_head; 385 struct fuse_forget_link *forget_list_tail; 386 387 /** Batching of FORGET requests (positive indicates FORGET batch) */ 388 int forget_batch; 389 390 /** Flag indicating if connection is blocked. This will be 391 the case before the INIT reply is received, and if there 392 are too many outstading backgrounds requests */ 393 int blocked; 394 395 /** waitq for blocked connection */ 396 wait_queue_head_t blocked_waitq; 397 398 /** waitq for reserved requests */ 399 wait_queue_head_t reserved_req_waitq; 400 401 /** The next unique request id */ 402 u64 reqctr; 403 404 /** Connection established, cleared on umount, connection 405 abort and device release */ 406 unsigned connected; 407 408 /** Connection failed (version mismatch). Cannot race with 409 setting other bitfields since it is only set once in INIT 410 reply, before any other request, and never cleared */ 411 unsigned conn_error:1; 412 413 /** Connection successful. Only set in INIT */ 414 unsigned conn_init:1; 415 416 /** Do readpages asynchronously? Only set in INIT */ 417 unsigned async_read:1; 418 419 /** Do not send separate SETATTR request before open(O_TRUNC) */ 420 unsigned atomic_o_trunc:1; 421 422 /** Filesystem supports NFS exporting. Only set in INIT */ 423 unsigned export_support:1; 424 425 /** Set if bdi is valid */ 426 unsigned bdi_initialized:1; 427 428 /* 429 * The following bitfields are only for optimization purposes 430 * and hence races in setting them will not cause malfunction 431 */ 432 433 /** Is fsync not implemented by fs? */ 434 unsigned no_fsync:1; 435 436 /** Is fsyncdir not implemented by fs? */ 437 unsigned no_fsyncdir:1; 438 439 /** Is flush not implemented by fs? */ 440 unsigned no_flush:1; 441 442 /** Is setxattr not implemented by fs? */ 443 unsigned no_setxattr:1; 444 445 /** Is getxattr not implemented by fs? */ 446 unsigned no_getxattr:1; 447 448 /** Is listxattr not implemented by fs? */ 449 unsigned no_listxattr:1; 450 451 /** Is removexattr not implemented by fs? */ 452 unsigned no_removexattr:1; 453 454 /** Are posix file locking primitives not implemented by fs? */ 455 unsigned no_lock:1; 456 457 /** Is access not implemented by fs? */ 458 unsigned no_access:1; 459 460 /** Is create not implemented by fs? */ 461 unsigned no_create:1; 462 463 /** Is interrupt not implemented by fs? */ 464 unsigned no_interrupt:1; 465 466 /** Is bmap not implemented by fs? */ 467 unsigned no_bmap:1; 468 469 /** Is poll not implemented by fs? */ 470 unsigned no_poll:1; 471 472 /** Do multi-page cached writes */ 473 unsigned big_writes:1; 474 475 /** Don't apply umask to creation modes */ 476 unsigned dont_mask:1; 477 478 /** Are BSD file locking primitives not implemented by fs? */ 479 unsigned no_flock:1; 480 481 /** The number of requests waiting for completion */ 482 atomic_t num_waiting; 483 484 /** Negotiated minor version */ 485 unsigned minor; 486 487 /** Backing dev info */ 488 struct backing_dev_info bdi; 489 490 /** Entry on the fuse_conn_list */ 491 struct list_head entry; 492 493 /** Device ID from super block */ 494 dev_t dev; 495 496 /** Dentries in the control filesystem */ 497 struct dentry *ctl_dentry[FUSE_CTL_NUM_DENTRIES]; 498 499 /** number of dentries used in the above array */ 500 int ctl_ndents; 501 502 /** O_ASYNC requests */ 503 struct fasync_struct *fasync; 504 505 /** Key for lock owner ID scrambling */ 506 u32 scramble_key[4]; 507 508 /** Reserved request for the DESTROY message */ 509 struct fuse_req *destroy_req; 510 511 /** Version counter for attribute changes */ 512 u64 attr_version; 513 514 /** Called on final put */ 515 void (*release)(struct fuse_conn *); 516 517 /** Super block for this connection. */ 518 struct super_block *sb; 519 520 /** Read/write semaphore to hold when accessing sb. */ 521 struct rw_semaphore killsb; 522 }; 523 524 static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb) 525 { 526 return sb->s_fs_info; 527 } 528 529 static inline struct fuse_conn *get_fuse_conn(struct inode *inode) 530 { 531 return get_fuse_conn_super(inode->i_sb); 532 } 533 534 static inline struct fuse_inode *get_fuse_inode(struct inode *inode) 535 { 536 return container_of(inode, struct fuse_inode, inode); 537 } 538 539 static inline u64 get_node_id(struct inode *inode) 540 { 541 return get_fuse_inode(inode)->nodeid; 542 } 543 544 /** Device operations */ 545 extern const struct file_operations fuse_dev_operations; 546 547 extern const struct dentry_operations fuse_dentry_operations; 548 549 /** 550 * Inode to nodeid comparison. 551 */ 552 int fuse_inode_eq(struct inode *inode, void *_nodeidp); 553 554 /** 555 * Get a filled in inode 556 */ 557 struct inode *fuse_iget(struct super_block *sb, u64 nodeid, 558 int generation, struct fuse_attr *attr, 559 u64 attr_valid, u64 attr_version); 560 561 int fuse_lookup_name(struct super_block *sb, u64 nodeid, struct qstr *name, 562 struct fuse_entry_out *outarg, struct inode **inode); 563 564 /** 565 * Send FORGET command 566 */ 567 void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget, 568 u64 nodeid, u64 nlookup); 569 570 struct fuse_forget_link *fuse_alloc_forget(void); 571 572 /** 573 * Initialize READ or READDIR request 574 */ 575 void fuse_read_fill(struct fuse_req *req, struct file *file, 576 loff_t pos, size_t count, int opcode); 577 578 /** 579 * Send OPEN or OPENDIR request 580 */ 581 int fuse_open_common(struct inode *inode, struct file *file, bool isdir); 582 583 struct fuse_file *fuse_file_alloc(struct fuse_conn *fc); 584 struct fuse_file *fuse_file_get(struct fuse_file *ff); 585 void fuse_file_free(struct fuse_file *ff); 586 void fuse_finish_open(struct inode *inode, struct file *file); 587 588 void fuse_sync_release(struct fuse_file *ff, int flags); 589 590 /** 591 * Send RELEASE or RELEASEDIR request 592 */ 593 void fuse_release_common(struct file *file, int opcode); 594 595 /** 596 * Send FSYNC or FSYNCDIR request 597 */ 598 int fuse_fsync_common(struct file *file, loff_t start, loff_t end, 599 int datasync, int isdir); 600 601 /** 602 * Notify poll wakeup 603 */ 604 int fuse_notify_poll_wakeup(struct fuse_conn *fc, 605 struct fuse_notify_poll_wakeup_out *outarg); 606 607 /** 608 * Initialize file operations on a regular file 609 */ 610 void fuse_init_file_inode(struct inode *inode); 611 612 /** 613 * Initialize inode operations on regular files and special files 614 */ 615 void fuse_init_common(struct inode *inode); 616 617 /** 618 * Initialize inode and file operations on a directory 619 */ 620 void fuse_init_dir(struct inode *inode); 621 622 /** 623 * Initialize inode operations on a symlink 624 */ 625 void fuse_init_symlink(struct inode *inode); 626 627 /** 628 * Change attributes of an inode 629 */ 630 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr, 631 u64 attr_valid, u64 attr_version); 632 633 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr, 634 u64 attr_valid); 635 636 /** 637 * Initialize the client device 638 */ 639 int fuse_dev_init(void); 640 641 /** 642 * Cleanup the client device 643 */ 644 void fuse_dev_cleanup(void); 645 646 int fuse_ctl_init(void); 647 void fuse_ctl_cleanup(void); 648 649 /** 650 * Allocate a request 651 */ 652 struct fuse_req *fuse_request_alloc(void); 653 654 struct fuse_req *fuse_request_alloc_nofs(void); 655 656 /** 657 * Free a request 658 */ 659 void fuse_request_free(struct fuse_req *req); 660 661 /** 662 * Get a request, may fail with -ENOMEM 663 */ 664 struct fuse_req *fuse_get_req(struct fuse_conn *fc); 665 666 /** 667 * Gets a requests for a file operation, always succeeds 668 */ 669 struct fuse_req *fuse_get_req_nofail(struct fuse_conn *fc, struct file *file); 670 671 /** 672 * Decrement reference count of a request. If count goes to zero free 673 * the request. 674 */ 675 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req); 676 677 /** 678 * Send a request (synchronous) 679 */ 680 void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req); 681 682 /** 683 * Send a request in the background 684 */ 685 void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req); 686 687 void fuse_request_send_background_locked(struct fuse_conn *fc, 688 struct fuse_req *req); 689 690 /* Abort all requests */ 691 void fuse_abort_conn(struct fuse_conn *fc); 692 693 /** 694 * Invalidate inode attributes 695 */ 696 void fuse_invalidate_attr(struct inode *inode); 697 698 void fuse_invalidate_entry_cache(struct dentry *entry); 699 700 /** 701 * Acquire reference to fuse_conn 702 */ 703 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc); 704 705 void fuse_conn_kill(struct fuse_conn *fc); 706 707 /** 708 * Initialize fuse_conn 709 */ 710 void fuse_conn_init(struct fuse_conn *fc); 711 712 /** 713 * Release reference to fuse_conn 714 */ 715 void fuse_conn_put(struct fuse_conn *fc); 716 717 /** 718 * Add connection to control filesystem 719 */ 720 int fuse_ctl_add_conn(struct fuse_conn *fc); 721 722 /** 723 * Remove connection from control filesystem 724 */ 725 void fuse_ctl_remove_conn(struct fuse_conn *fc); 726 727 /** 728 * Is file type valid? 729 */ 730 int fuse_valid_type(int m); 731 732 /** 733 * Is task allowed to perform filesystem operation? 734 */ 735 int fuse_allow_task(struct fuse_conn *fc, struct task_struct *task); 736 737 u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id); 738 739 int fuse_update_attributes(struct inode *inode, struct kstat *stat, 740 struct file *file, bool *refreshed); 741 742 void fuse_flush_writepages(struct inode *inode); 743 744 void fuse_set_nowrite(struct inode *inode); 745 void fuse_release_nowrite(struct inode *inode); 746 747 u64 fuse_get_attr_version(struct fuse_conn *fc); 748 749 /** 750 * File-system tells the kernel to invalidate cache for the given node id. 751 */ 752 int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid, 753 loff_t offset, loff_t len); 754 755 /** 756 * File-system tells the kernel to invalidate parent attributes and 757 * the dentry matching parent/name. 758 * 759 * If the child_nodeid is non-zero and: 760 * - matches the inode number for the dentry matching parent/name, 761 * - is not a mount point 762 * - is a file or oan empty directory 763 * then the dentry is unhashed (d_delete()). 764 */ 765 int fuse_reverse_inval_entry(struct super_block *sb, u64 parent_nodeid, 766 u64 child_nodeid, struct qstr *name); 767 768 int fuse_do_open(struct fuse_conn *fc, u64 nodeid, struct file *file, 769 bool isdir); 770 ssize_t fuse_direct_io(struct file *file, const char __user *buf, 771 size_t count, loff_t *ppos, int write); 772 long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg, 773 unsigned int flags); 774 long fuse_ioctl_common(struct file *file, unsigned int cmd, 775 unsigned long arg, unsigned int flags); 776 unsigned fuse_file_poll(struct file *file, poll_table *wait); 777 int fuse_dev_release(struct inode *inode, struct file *file); 778 779 void fuse_write_update_size(struct inode *inode, loff_t pos); 780 781 #endif /* _FS_FUSE_I_H */ 782