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 kuid_t user_id; 337 338 /** The group id for this mount */ 339 kgid_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 /** Use enhanced/automatic page cache invalidation. */ 488 unsigned auto_inval_data:1; 489 490 /** The number of requests waiting for completion */ 491 atomic_t num_waiting; 492 493 /** Negotiated minor version */ 494 unsigned minor; 495 496 /** Backing dev info */ 497 struct backing_dev_info bdi; 498 499 /** Entry on the fuse_conn_list */ 500 struct list_head entry; 501 502 /** Device ID from super block */ 503 dev_t dev; 504 505 /** Dentries in the control filesystem */ 506 struct dentry *ctl_dentry[FUSE_CTL_NUM_DENTRIES]; 507 508 /** number of dentries used in the above array */ 509 int ctl_ndents; 510 511 /** O_ASYNC requests */ 512 struct fasync_struct *fasync; 513 514 /** Key for lock owner ID scrambling */ 515 u32 scramble_key[4]; 516 517 /** Reserved request for the DESTROY message */ 518 struct fuse_req *destroy_req; 519 520 /** Version counter for attribute changes */ 521 u64 attr_version; 522 523 /** Called on final put */ 524 void (*release)(struct fuse_conn *); 525 526 /** Super block for this connection. */ 527 struct super_block *sb; 528 529 /** Read/write semaphore to hold when accessing sb. */ 530 struct rw_semaphore killsb; 531 }; 532 533 static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb) 534 { 535 return sb->s_fs_info; 536 } 537 538 static inline struct fuse_conn *get_fuse_conn(struct inode *inode) 539 { 540 return get_fuse_conn_super(inode->i_sb); 541 } 542 543 static inline struct fuse_inode *get_fuse_inode(struct inode *inode) 544 { 545 return container_of(inode, struct fuse_inode, inode); 546 } 547 548 static inline u64 get_node_id(struct inode *inode) 549 { 550 return get_fuse_inode(inode)->nodeid; 551 } 552 553 /** Device operations */ 554 extern const struct file_operations fuse_dev_operations; 555 556 extern const struct dentry_operations fuse_dentry_operations; 557 558 /** 559 * Inode to nodeid comparison. 560 */ 561 int fuse_inode_eq(struct inode *inode, void *_nodeidp); 562 563 /** 564 * Get a filled in inode 565 */ 566 struct inode *fuse_iget(struct super_block *sb, u64 nodeid, 567 int generation, struct fuse_attr *attr, 568 u64 attr_valid, u64 attr_version); 569 570 int fuse_lookup_name(struct super_block *sb, u64 nodeid, struct qstr *name, 571 struct fuse_entry_out *outarg, struct inode **inode); 572 573 /** 574 * Send FORGET command 575 */ 576 void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget, 577 u64 nodeid, u64 nlookup); 578 579 struct fuse_forget_link *fuse_alloc_forget(void); 580 581 /** 582 * Initialize READ or READDIR request 583 */ 584 void fuse_read_fill(struct fuse_req *req, struct file *file, 585 loff_t pos, size_t count, int opcode); 586 587 /** 588 * Send OPEN or OPENDIR request 589 */ 590 int fuse_open_common(struct inode *inode, struct file *file, bool isdir); 591 592 struct fuse_file *fuse_file_alloc(struct fuse_conn *fc); 593 struct fuse_file *fuse_file_get(struct fuse_file *ff); 594 void fuse_file_free(struct fuse_file *ff); 595 void fuse_finish_open(struct inode *inode, struct file *file); 596 597 void fuse_sync_release(struct fuse_file *ff, int flags); 598 599 /** 600 * Send RELEASE or RELEASEDIR request 601 */ 602 void fuse_release_common(struct file *file, int opcode); 603 604 /** 605 * Send FSYNC or FSYNCDIR request 606 */ 607 int fuse_fsync_common(struct file *file, loff_t start, loff_t end, 608 int datasync, int isdir); 609 610 /** 611 * Notify poll wakeup 612 */ 613 int fuse_notify_poll_wakeup(struct fuse_conn *fc, 614 struct fuse_notify_poll_wakeup_out *outarg); 615 616 /** 617 * Initialize file operations on a regular file 618 */ 619 void fuse_init_file_inode(struct inode *inode); 620 621 /** 622 * Initialize inode operations on regular files and special files 623 */ 624 void fuse_init_common(struct inode *inode); 625 626 /** 627 * Initialize inode and file operations on a directory 628 */ 629 void fuse_init_dir(struct inode *inode); 630 631 /** 632 * Initialize inode operations on a symlink 633 */ 634 void fuse_init_symlink(struct inode *inode); 635 636 /** 637 * Change attributes of an inode 638 */ 639 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr, 640 u64 attr_valid, u64 attr_version); 641 642 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr, 643 u64 attr_valid); 644 645 /** 646 * Initialize the client device 647 */ 648 int fuse_dev_init(void); 649 650 /** 651 * Cleanup the client device 652 */ 653 void fuse_dev_cleanup(void); 654 655 int fuse_ctl_init(void); 656 void fuse_ctl_cleanup(void); 657 658 /** 659 * Allocate a request 660 */ 661 struct fuse_req *fuse_request_alloc(void); 662 663 struct fuse_req *fuse_request_alloc_nofs(void); 664 665 /** 666 * Free a request 667 */ 668 void fuse_request_free(struct fuse_req *req); 669 670 /** 671 * Get a request, may fail with -ENOMEM 672 */ 673 struct fuse_req *fuse_get_req(struct fuse_conn *fc); 674 675 /** 676 * Gets a requests for a file operation, always succeeds 677 */ 678 struct fuse_req *fuse_get_req_nofail(struct fuse_conn *fc, struct file *file); 679 680 /** 681 * Decrement reference count of a request. If count goes to zero free 682 * the request. 683 */ 684 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req); 685 686 /** 687 * Send a request (synchronous) 688 */ 689 void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req); 690 691 /** 692 * Send a request in the background 693 */ 694 void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req); 695 696 void fuse_request_send_background_locked(struct fuse_conn *fc, 697 struct fuse_req *req); 698 699 /* Abort all requests */ 700 void fuse_abort_conn(struct fuse_conn *fc); 701 702 /** 703 * Invalidate inode attributes 704 */ 705 void fuse_invalidate_attr(struct inode *inode); 706 707 void fuse_invalidate_entry_cache(struct dentry *entry); 708 709 /** 710 * Acquire reference to fuse_conn 711 */ 712 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc); 713 714 void fuse_conn_kill(struct fuse_conn *fc); 715 716 /** 717 * Initialize fuse_conn 718 */ 719 void fuse_conn_init(struct fuse_conn *fc); 720 721 /** 722 * Release reference to fuse_conn 723 */ 724 void fuse_conn_put(struct fuse_conn *fc); 725 726 /** 727 * Add connection to control filesystem 728 */ 729 int fuse_ctl_add_conn(struct fuse_conn *fc); 730 731 /** 732 * Remove connection from control filesystem 733 */ 734 void fuse_ctl_remove_conn(struct fuse_conn *fc); 735 736 /** 737 * Is file type valid? 738 */ 739 int fuse_valid_type(int m); 740 741 /** 742 * Is task allowed to perform filesystem operation? 743 */ 744 int fuse_allow_task(struct fuse_conn *fc, struct task_struct *task); 745 746 u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id); 747 748 int fuse_update_attributes(struct inode *inode, struct kstat *stat, 749 struct file *file, bool *refreshed); 750 751 void fuse_flush_writepages(struct inode *inode); 752 753 void fuse_set_nowrite(struct inode *inode); 754 void fuse_release_nowrite(struct inode *inode); 755 756 u64 fuse_get_attr_version(struct fuse_conn *fc); 757 758 /** 759 * File-system tells the kernel to invalidate cache for the given node id. 760 */ 761 int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid, 762 loff_t offset, loff_t len); 763 764 /** 765 * File-system tells the kernel to invalidate parent attributes and 766 * the dentry matching parent/name. 767 * 768 * If the child_nodeid is non-zero and: 769 * - matches the inode number for the dentry matching parent/name, 770 * - is not a mount point 771 * - is a file or oan empty directory 772 * then the dentry is unhashed (d_delete()). 773 */ 774 int fuse_reverse_inval_entry(struct super_block *sb, u64 parent_nodeid, 775 u64 child_nodeid, struct qstr *name); 776 777 int fuse_do_open(struct fuse_conn *fc, u64 nodeid, struct file *file, 778 bool isdir); 779 ssize_t fuse_direct_io(struct file *file, const char __user *buf, 780 size_t count, loff_t *ppos, int write); 781 long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg, 782 unsigned int flags); 783 long fuse_ioctl_common(struct file *file, unsigned int cmd, 784 unsigned long arg, unsigned int flags); 785 unsigned fuse_file_poll(struct file *file, poll_table *wait); 786 int fuse_dev_release(struct inode *inode, struct file *file); 787 788 void fuse_write_update_size(struct inode *inode, loff_t pos); 789 790 #endif /* _FS_FUSE_I_H */ 791