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