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