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 /** 64 bit inode number */ 86 u64 orig_ino; 87 88 /** Version of last attribute change */ 89 u64 attr_version; 90 91 /** Files usable in writepage. Protected by fc->lock */ 92 struct list_head write_files; 93 94 /** Writepages pending on truncate or fsync */ 95 struct list_head queued_writes; 96 97 /** Number of sent writes, a negative bias (FUSE_NOWRITE) 98 * means more writes are blocked */ 99 int writectr; 100 101 /** Waitq for writepage completion */ 102 wait_queue_head_t page_waitq; 103 104 /** List of writepage requestst (pending or sent) */ 105 struct list_head writepages; 106 }; 107 108 struct fuse_conn; 109 110 /** FUSE specific file data */ 111 struct fuse_file { 112 /** Fuse connection for this file */ 113 struct fuse_conn *fc; 114 115 /** Request reserved for flush and release */ 116 struct fuse_req *reserved_req; 117 118 /** Kernel file handle guaranteed to be unique */ 119 u64 kh; 120 121 /** File handle used by userspace */ 122 u64 fh; 123 124 /** Node id of this file */ 125 u64 nodeid; 126 127 /** Refcount */ 128 atomic_t count; 129 130 /** FOPEN_* flags returned by open */ 131 u32 open_flags; 132 133 /** Entry on inode's write_files list */ 134 struct list_head write_entry; 135 136 /** RB node to be linked on fuse_conn->polled_files */ 137 struct rb_node polled_node; 138 139 /** Wait queue head for poll */ 140 wait_queue_head_t poll_wait; 141 142 /** Has flock been performed on this file? */ 143 bool flock:1; 144 }; 145 146 /** One input argument of a request */ 147 struct fuse_in_arg { 148 unsigned size; 149 const void *value; 150 }; 151 152 /** The request input */ 153 struct fuse_in { 154 /** The request header */ 155 struct fuse_in_header h; 156 157 /** True if the data for the last argument is in req->pages */ 158 unsigned argpages:1; 159 160 /** Number of arguments */ 161 unsigned numargs; 162 163 /** Array of arguments */ 164 struct fuse_in_arg args[3]; 165 }; 166 167 /** One output argument of a request */ 168 struct fuse_arg { 169 unsigned size; 170 void *value; 171 }; 172 173 /** The request output */ 174 struct fuse_out { 175 /** Header returned from userspace */ 176 struct fuse_out_header h; 177 178 /* 179 * The following bitfields are not changed during the request 180 * processing 181 */ 182 183 /** Last argument is variable length (can be shorter than 184 arg->size) */ 185 unsigned argvar:1; 186 187 /** Last argument is a list of pages to copy data to */ 188 unsigned argpages:1; 189 190 /** Zero partially or not copied pages */ 191 unsigned page_zeroing:1; 192 193 /** Pages may be replaced with new ones */ 194 unsigned page_replace:1; 195 196 /** Number or arguments */ 197 unsigned numargs; 198 199 /** Array of arguments */ 200 struct fuse_arg args[3]; 201 }; 202 203 /** The request state */ 204 enum fuse_req_state { 205 FUSE_REQ_INIT = 0, 206 FUSE_REQ_PENDING, 207 FUSE_REQ_READING, 208 FUSE_REQ_SENT, 209 FUSE_REQ_WRITING, 210 FUSE_REQ_FINISHED 211 }; 212 213 /** 214 * A request to the client 215 */ 216 struct fuse_req { 217 /** This can be on either pending processing or io lists in 218 fuse_conn */ 219 struct list_head list; 220 221 /** Entry on the interrupts list */ 222 struct list_head intr_entry; 223 224 /** refcount */ 225 atomic_t count; 226 227 /** Unique ID for the interrupt request */ 228 u64 intr_unique; 229 230 /* 231 * The following bitfields are either set once before the 232 * request is queued or setting/clearing them is protected by 233 * fuse_conn->lock 234 */ 235 236 /** True if the request has reply */ 237 unsigned isreply:1; 238 239 /** Force sending of the request even if interrupted */ 240 unsigned force:1; 241 242 /** The request was aborted */ 243 unsigned aborted:1; 244 245 /** Request is sent in the background */ 246 unsigned background:1; 247 248 /** The request has been interrupted */ 249 unsigned interrupted:1; 250 251 /** Data is being copied to/from the request */ 252 unsigned locked:1; 253 254 /** Request is counted as "waiting" */ 255 unsigned waiting:1; 256 257 /** State of the request */ 258 enum fuse_req_state state; 259 260 /** The request input */ 261 struct fuse_in in; 262 263 /** The request output */ 264 struct fuse_out out; 265 266 /** Used to wake up the task waiting for completion of request*/ 267 wait_queue_head_t waitq; 268 269 /** Data for asynchronous requests */ 270 union { 271 struct { 272 union { 273 struct fuse_release_in in; 274 struct work_struct work; 275 }; 276 struct path path; 277 } release; 278 struct fuse_init_in init_in; 279 struct fuse_init_out init_out; 280 struct cuse_init_in cuse_init_in; 281 struct { 282 struct fuse_read_in in; 283 u64 attr_ver; 284 } read; 285 struct { 286 struct fuse_write_in in; 287 struct fuse_write_out out; 288 } write; 289 struct fuse_notify_retrieve_in retrieve_in; 290 struct fuse_lk_in lk_in; 291 } misc; 292 293 /** page vector */ 294 struct page *pages[FUSE_MAX_PAGES_PER_REQ]; 295 296 /** number of pages in vector */ 297 unsigned num_pages; 298 299 /** offset of data on first page */ 300 unsigned page_offset; 301 302 /** File used in the request (or NULL) */ 303 struct fuse_file *ff; 304 305 /** Inode used in the request or NULL */ 306 struct inode *inode; 307 308 /** Link on fi->writepages */ 309 struct list_head writepages_entry; 310 311 /** Request completion callback */ 312 void (*end)(struct fuse_conn *, struct fuse_req *); 313 314 /** Request is stolen from fuse_file->reserved_req */ 315 struct file *stolen_file; 316 }; 317 318 /** 319 * A Fuse connection. 320 * 321 * This structure is created, when the filesystem is mounted, and is 322 * destroyed, when the client device is closed and the filesystem is 323 * unmounted. 324 */ 325 struct fuse_conn { 326 /** Lock protecting accessess to members of this structure */ 327 spinlock_t lock; 328 329 /** Mutex protecting against directory alias creation */ 330 struct mutex inst_mutex; 331 332 /** Refcount */ 333 atomic_t count; 334 335 /** The user id for this mount */ 336 uid_t user_id; 337 338 /** The group id for this mount */ 339 gid_t group_id; 340 341 /** The fuse mount flags for this mount */ 342 unsigned flags; 343 344 /** Maximum read size */ 345 unsigned max_read; 346 347 /** Maximum write size */ 348 unsigned max_write; 349 350 /** Readers of the connection are waiting on this */ 351 wait_queue_head_t waitq; 352 353 /** The list of pending requests */ 354 struct list_head pending; 355 356 /** The list of requests being processed */ 357 struct list_head processing; 358 359 /** The list of requests under I/O */ 360 struct list_head io; 361 362 /** The next unique kernel file handle */ 363 u64 khctr; 364 365 /** rbtree of fuse_files waiting for poll events indexed by ph */ 366 struct rb_root polled_files; 367 368 /** Maximum number of outstanding background requests */ 369 unsigned max_background; 370 371 /** Number of background requests at which congestion starts */ 372 unsigned congestion_threshold; 373 374 /** Number of requests currently in the background */ 375 unsigned num_background; 376 377 /** Number of background requests currently queued for userspace */ 378 unsigned active_background; 379 380 /** The list of background requests set aside for later queuing */ 381 struct list_head bg_queue; 382 383 /** Pending interrupts */ 384 struct list_head interrupts; 385 386 /** Queue of pending forgets */ 387 struct fuse_forget_link forget_list_head; 388 struct fuse_forget_link *forget_list_tail; 389 390 /** Batching of FORGET requests (positive indicates FORGET batch) */ 391 int forget_batch; 392 393 /** Flag indicating if connection is blocked. This will be 394 the case before the INIT reply is received, and if there 395 are too many outstading backgrounds requests */ 396 int blocked; 397 398 /** waitq for blocked connection */ 399 wait_queue_head_t blocked_waitq; 400 401 /** waitq for reserved requests */ 402 wait_queue_head_t reserved_req_waitq; 403 404 /** The next unique request id */ 405 u64 reqctr; 406 407 /** Connection established, cleared on umount, connection 408 abort and device release */ 409 unsigned connected; 410 411 /** Connection failed (version mismatch). Cannot race with 412 setting other bitfields since it is only set once in INIT 413 reply, before any other request, and never cleared */ 414 unsigned conn_error:1; 415 416 /** Connection successful. Only set in INIT */ 417 unsigned conn_init:1; 418 419 /** Do readpages asynchronously? Only set in INIT */ 420 unsigned async_read:1; 421 422 /** Do not send separate SETATTR request before open(O_TRUNC) */ 423 unsigned atomic_o_trunc:1; 424 425 /** Filesystem supports NFS exporting. Only set in INIT */ 426 unsigned export_support:1; 427 428 /** Set if bdi is valid */ 429 unsigned bdi_initialized:1; 430 431 /* 432 * The following bitfields are only for optimization purposes 433 * and hence races in setting them will not cause malfunction 434 */ 435 436 /** Is fsync not implemented by fs? */ 437 unsigned no_fsync:1; 438 439 /** Is fsyncdir not implemented by fs? */ 440 unsigned no_fsyncdir:1; 441 442 /** Is flush not implemented by fs? */ 443 unsigned no_flush:1; 444 445 /** Is setxattr not implemented by fs? */ 446 unsigned no_setxattr:1; 447 448 /** Is getxattr not implemented by fs? */ 449 unsigned no_getxattr:1; 450 451 /** Is listxattr not implemented by fs? */ 452 unsigned no_listxattr:1; 453 454 /** Is removexattr not implemented by fs? */ 455 unsigned no_removexattr:1; 456 457 /** Are posix file locking primitives not implemented by fs? */ 458 unsigned no_lock:1; 459 460 /** Is access not implemented by fs? */ 461 unsigned no_access:1; 462 463 /** Is create not implemented by fs? */ 464 unsigned no_create:1; 465 466 /** Is interrupt not implemented by fs? */ 467 unsigned no_interrupt:1; 468 469 /** Is bmap not implemented by fs? */ 470 unsigned no_bmap:1; 471 472 /** Is poll not implemented by fs? */ 473 unsigned no_poll:1; 474 475 /** Do multi-page cached writes */ 476 unsigned big_writes:1; 477 478 /** Don't apply umask to creation modes */ 479 unsigned dont_mask:1; 480 481 /** Are BSD file locking primitives not implemented by fs? */ 482 unsigned no_flock:1; 483 484 /** Is fallocate not implemented by fs? */ 485 unsigned no_fallocate:1; 486 487 /** The number of requests waiting for completion */ 488 atomic_t num_waiting; 489 490 /** Negotiated minor version */ 491 unsigned minor; 492 493 /** Backing dev info */ 494 struct backing_dev_info bdi; 495 496 /** Entry on the fuse_conn_list */ 497 struct list_head entry; 498 499 /** Device ID from super block */ 500 dev_t dev; 501 502 /** Dentries in the control filesystem */ 503 struct dentry *ctl_dentry[FUSE_CTL_NUM_DENTRIES]; 504 505 /** number of dentries used in the above array */ 506 int ctl_ndents; 507 508 /** O_ASYNC requests */ 509 struct fasync_struct *fasync; 510 511 /** Key for lock owner ID scrambling */ 512 u32 scramble_key[4]; 513 514 /** Reserved request for the DESTROY message */ 515 struct fuse_req *destroy_req; 516 517 /** Version counter for attribute changes */ 518 u64 attr_version; 519 520 /** Called on final put */ 521 void (*release)(struct fuse_conn *); 522 523 /** Super block for this connection. */ 524 struct super_block *sb; 525 526 /** Read/write semaphore to hold when accessing sb. */ 527 struct rw_semaphore killsb; 528 }; 529 530 static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb) 531 { 532 return sb->s_fs_info; 533 } 534 535 static inline struct fuse_conn *get_fuse_conn(struct inode *inode) 536 { 537 return get_fuse_conn_super(inode->i_sb); 538 } 539 540 static inline struct fuse_inode *get_fuse_inode(struct inode *inode) 541 { 542 return container_of(inode, struct fuse_inode, inode); 543 } 544 545 static inline u64 get_node_id(struct inode *inode) 546 { 547 return get_fuse_inode(inode)->nodeid; 548 } 549 550 /** Device operations */ 551 extern const struct file_operations fuse_dev_operations; 552 553 extern const struct dentry_operations fuse_dentry_operations; 554 555 /** 556 * Inode to nodeid comparison. 557 */ 558 int fuse_inode_eq(struct inode *inode, void *_nodeidp); 559 560 /** 561 * Get a filled in inode 562 */ 563 struct inode *fuse_iget(struct super_block *sb, u64 nodeid, 564 int generation, struct fuse_attr *attr, 565 u64 attr_valid, u64 attr_version); 566 567 int fuse_lookup_name(struct super_block *sb, u64 nodeid, struct qstr *name, 568 struct fuse_entry_out *outarg, struct inode **inode); 569 570 /** 571 * Send FORGET command 572 */ 573 void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget, 574 u64 nodeid, u64 nlookup); 575 576 struct fuse_forget_link *fuse_alloc_forget(void); 577 578 /** 579 * Initialize READ or READDIR request 580 */ 581 void fuse_read_fill(struct fuse_req *req, struct file *file, 582 loff_t pos, size_t count, int opcode); 583 584 /** 585 * Send OPEN or OPENDIR request 586 */ 587 int fuse_open_common(struct inode *inode, struct file *file, bool isdir); 588 589 struct fuse_file *fuse_file_alloc(struct fuse_conn *fc); 590 struct fuse_file *fuse_file_get(struct fuse_file *ff); 591 void fuse_file_free(struct fuse_file *ff); 592 void fuse_finish_open(struct inode *inode, struct file *file); 593 594 void fuse_sync_release(struct fuse_file *ff, int flags); 595 596 /** 597 * Send RELEASE or RELEASEDIR request 598 */ 599 void fuse_release_common(struct file *file, int opcode); 600 601 /** 602 * Send FSYNC or FSYNCDIR request 603 */ 604 int fuse_fsync_common(struct file *file, loff_t start, loff_t end, 605 int datasync, int isdir); 606 607 /** 608 * Notify poll wakeup 609 */ 610 int fuse_notify_poll_wakeup(struct fuse_conn *fc, 611 struct fuse_notify_poll_wakeup_out *outarg); 612 613 /** 614 * Initialize file operations on a regular file 615 */ 616 void fuse_init_file_inode(struct inode *inode); 617 618 /** 619 * Initialize inode operations on regular files and special files 620 */ 621 void fuse_init_common(struct inode *inode); 622 623 /** 624 * Initialize inode and file operations on a directory 625 */ 626 void fuse_init_dir(struct inode *inode); 627 628 /** 629 * Initialize inode operations on a symlink 630 */ 631 void fuse_init_symlink(struct inode *inode); 632 633 /** 634 * Change attributes of an inode 635 */ 636 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr, 637 u64 attr_valid, u64 attr_version); 638 639 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr, 640 u64 attr_valid); 641 642 /** 643 * Initialize the client device 644 */ 645 int fuse_dev_init(void); 646 647 /** 648 * Cleanup the client device 649 */ 650 void fuse_dev_cleanup(void); 651 652 int fuse_ctl_init(void); 653 void fuse_ctl_cleanup(void); 654 655 /** 656 * Allocate a request 657 */ 658 struct fuse_req *fuse_request_alloc(void); 659 660 struct fuse_req *fuse_request_alloc_nofs(void); 661 662 /** 663 * Free a request 664 */ 665 void fuse_request_free(struct fuse_req *req); 666 667 /** 668 * Get a request, may fail with -ENOMEM 669 */ 670 struct fuse_req *fuse_get_req(struct fuse_conn *fc); 671 672 /** 673 * Gets a requests for a file operation, always succeeds 674 */ 675 struct fuse_req *fuse_get_req_nofail(struct fuse_conn *fc, struct file *file); 676 677 /** 678 * Decrement reference count of a request. If count goes to zero free 679 * the request. 680 */ 681 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req); 682 683 /** 684 * Send a request (synchronous) 685 */ 686 void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req); 687 688 /** 689 * Send a request in the background 690 */ 691 void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req); 692 693 void fuse_request_send_background_locked(struct fuse_conn *fc, 694 struct fuse_req *req); 695 696 /* Abort all requests */ 697 void fuse_abort_conn(struct fuse_conn *fc); 698 699 /** 700 * Invalidate inode attributes 701 */ 702 void fuse_invalidate_attr(struct inode *inode); 703 704 void fuse_invalidate_entry_cache(struct dentry *entry); 705 706 /** 707 * Acquire reference to fuse_conn 708 */ 709 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc); 710 711 void fuse_conn_kill(struct fuse_conn *fc); 712 713 /** 714 * Initialize fuse_conn 715 */ 716 void fuse_conn_init(struct fuse_conn *fc); 717 718 /** 719 * Release reference to fuse_conn 720 */ 721 void fuse_conn_put(struct fuse_conn *fc); 722 723 /** 724 * Add connection to control filesystem 725 */ 726 int fuse_ctl_add_conn(struct fuse_conn *fc); 727 728 /** 729 * Remove connection from control filesystem 730 */ 731 void fuse_ctl_remove_conn(struct fuse_conn *fc); 732 733 /** 734 * Is file type valid? 735 */ 736 int fuse_valid_type(int m); 737 738 /** 739 * Is task allowed to perform filesystem operation? 740 */ 741 int fuse_allow_task(struct fuse_conn *fc, struct task_struct *task); 742 743 u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id); 744 745 int fuse_update_attributes(struct inode *inode, struct kstat *stat, 746 struct file *file, bool *refreshed); 747 748 void fuse_flush_writepages(struct inode *inode); 749 750 void fuse_set_nowrite(struct inode *inode); 751 void fuse_release_nowrite(struct inode *inode); 752 753 u64 fuse_get_attr_version(struct fuse_conn *fc); 754 755 /** 756 * File-system tells the kernel to invalidate cache for the given node id. 757 */ 758 int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid, 759 loff_t offset, loff_t len); 760 761 /** 762 * File-system tells the kernel to invalidate parent attributes and 763 * the dentry matching parent/name. 764 * 765 * If the child_nodeid is non-zero and: 766 * - matches the inode number for the dentry matching parent/name, 767 * - is not a mount point 768 * - is a file or oan empty directory 769 * then the dentry is unhashed (d_delete()). 770 */ 771 int fuse_reverse_inval_entry(struct super_block *sb, u64 parent_nodeid, 772 u64 child_nodeid, struct qstr *name); 773 774 int fuse_do_open(struct fuse_conn *fc, u64 nodeid, struct file *file, 775 bool isdir); 776 ssize_t fuse_direct_io(struct file *file, const char __user *buf, 777 size_t count, loff_t *ppos, int write); 778 long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg, 779 unsigned int flags); 780 long fuse_ioctl_common(struct file *file, unsigned int cmd, 781 unsigned long arg, unsigned int flags); 782 unsigned fuse_file_poll(struct file *file, poll_table *wait); 783 int fuse_dev_release(struct inode *inode, struct file *file); 784 785 void fuse_write_update_size(struct inode *inode, loff_t pos); 786 787 #endif /* _FS_FUSE_I_H */ 788