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