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 /** Maximum number of outstanding background requests */ 29 #define FUSE_MAX_BACKGROUND 12 30 31 /** Congestion starts at 75% of maximum */ 32 #define FUSE_CONGESTION_THRESHOLD (FUSE_MAX_BACKGROUND * 75 / 100) 33 34 /** Bias for fi->writectr, meaning new writepages must not be sent */ 35 #define FUSE_NOWRITE INT_MIN 36 37 /** It could be as large as PATH_MAX, but would that have any uses? */ 38 #define FUSE_NAME_MAX 1024 39 40 /** Number of dentries for each connection in the control filesystem */ 41 #define FUSE_CTL_NUM_DENTRIES 3 42 43 /** If the FUSE_DEFAULT_PERMISSIONS flag is given, the filesystem 44 module will check permissions based on the file mode. Otherwise no 45 permission checking is done in the kernel */ 46 #define FUSE_DEFAULT_PERMISSIONS (1 << 0) 47 48 /** If the FUSE_ALLOW_OTHER flag is given, then not only the user 49 doing the mount will be allowed to access the filesystem */ 50 #define FUSE_ALLOW_OTHER (1 << 1) 51 52 /** List of active connections */ 53 extern struct list_head fuse_conn_list; 54 55 /** Global mutex protecting fuse_conn_list and the control filesystem */ 56 extern struct mutex fuse_mutex; 57 58 /** FUSE inode */ 59 struct fuse_inode { 60 /** Inode data */ 61 struct inode inode; 62 63 /** Unique ID, which identifies the inode between userspace 64 * and kernel */ 65 u64 nodeid; 66 67 /** Number of lookups on this inode */ 68 u64 nlookup; 69 70 /** The request used for sending the FORGET message */ 71 struct fuse_req *forget_req; 72 73 /** Time in jiffies until the file attributes are valid */ 74 u64 i_time; 75 76 /** The sticky bit in inode->i_mode may have been removed, so 77 preserve the original mode */ 78 mode_t orig_i_mode; 79 80 /** Version of last attribute change */ 81 u64 attr_version; 82 83 /** Files usable in writepage. Protected by fc->lock */ 84 struct list_head write_files; 85 86 /** Writepages pending on truncate or fsync */ 87 struct list_head queued_writes; 88 89 /** Number of sent writes, a negative bias (FUSE_NOWRITE) 90 * means more writes are blocked */ 91 int writectr; 92 93 /** Waitq for writepage completion */ 94 wait_queue_head_t page_waitq; 95 96 /** List of writepage requestst (pending or sent) */ 97 struct list_head writepages; 98 }; 99 100 struct fuse_conn; 101 102 /** FUSE specific file data */ 103 struct fuse_file { 104 /** Fuse connection for this file */ 105 struct fuse_conn *fc; 106 107 /** Request reserved for flush and release */ 108 struct fuse_req *reserved_req; 109 110 /** Kernel file handle guaranteed to be unique */ 111 u64 kh; 112 113 /** File handle used by userspace */ 114 u64 fh; 115 116 /** Node id of this file */ 117 u64 nodeid; 118 119 /** Refcount */ 120 atomic_t count; 121 122 /** FOPEN_* flags returned by open */ 123 u32 open_flags; 124 125 /** Entry on inode's write_files list */ 126 struct list_head write_entry; 127 128 /** RB node to be linked on fuse_conn->polled_files */ 129 struct rb_node polled_node; 130 131 /** Wait queue head for poll */ 132 wait_queue_head_t poll_wait; 133 }; 134 135 /** One input argument of a request */ 136 struct fuse_in_arg { 137 unsigned size; 138 const void *value; 139 }; 140 141 /** The request input */ 142 struct fuse_in { 143 /** The request header */ 144 struct fuse_in_header h; 145 146 /** True if the data for the last argument is in req->pages */ 147 unsigned argpages:1; 148 149 /** Number of arguments */ 150 unsigned numargs; 151 152 /** Array of arguments */ 153 struct fuse_in_arg args[3]; 154 }; 155 156 /** One output argument of a request */ 157 struct fuse_arg { 158 unsigned size; 159 void *value; 160 }; 161 162 /** The request output */ 163 struct fuse_out { 164 /** Header returned from userspace */ 165 struct fuse_out_header h; 166 167 /* 168 * The following bitfields are not changed during the request 169 * processing 170 */ 171 172 /** Last argument is variable length (can be shorter than 173 arg->size) */ 174 unsigned argvar:1; 175 176 /** Last argument is a list of pages to copy data to */ 177 unsigned argpages:1; 178 179 /** Zero partially or not copied pages */ 180 unsigned page_zeroing:1; 181 182 /** Number or arguments */ 183 unsigned numargs; 184 185 /** Array of arguments */ 186 struct fuse_arg args[3]; 187 }; 188 189 /** The request state */ 190 enum fuse_req_state { 191 FUSE_REQ_INIT = 0, 192 FUSE_REQ_PENDING, 193 FUSE_REQ_READING, 194 FUSE_REQ_SENT, 195 FUSE_REQ_WRITING, 196 FUSE_REQ_FINISHED 197 }; 198 199 /** 200 * A request to the client 201 */ 202 struct fuse_req { 203 /** This can be on either pending processing or io lists in 204 fuse_conn */ 205 struct list_head list; 206 207 /** Entry on the interrupts list */ 208 struct list_head intr_entry; 209 210 /** refcount */ 211 atomic_t count; 212 213 /** Unique ID for the interrupt request */ 214 u64 intr_unique; 215 216 /* 217 * The following bitfields are either set once before the 218 * request is queued or setting/clearing them is protected by 219 * fuse_conn->lock 220 */ 221 222 /** True if the request has reply */ 223 unsigned isreply:1; 224 225 /** Force sending of the request even if interrupted */ 226 unsigned force:1; 227 228 /** The request was aborted */ 229 unsigned aborted:1; 230 231 /** Request is sent in the background */ 232 unsigned background:1; 233 234 /** The request has been interrupted */ 235 unsigned interrupted:1; 236 237 /** Data is being copied to/from the request */ 238 unsigned locked:1; 239 240 /** Request is counted as "waiting" */ 241 unsigned waiting:1; 242 243 /** State of the request */ 244 enum fuse_req_state state; 245 246 /** The request input */ 247 struct fuse_in in; 248 249 /** The request output */ 250 struct fuse_out out; 251 252 /** Used to wake up the task waiting for completion of request*/ 253 wait_queue_head_t waitq; 254 255 /** Data for asynchronous requests */ 256 union { 257 struct fuse_forget_in forget_in; 258 struct { 259 struct fuse_release_in in; 260 struct path path; 261 } release; 262 struct fuse_init_in init_in; 263 struct fuse_init_out init_out; 264 struct cuse_init_in cuse_init_in; 265 struct cuse_init_out cuse_init_out; 266 struct { 267 struct fuse_read_in in; 268 u64 attr_ver; 269 } read; 270 struct { 271 struct fuse_write_in in; 272 struct fuse_write_out out; 273 } write; 274 struct fuse_lk_in lk_in; 275 } misc; 276 277 /** page vector */ 278 struct page *pages[FUSE_MAX_PAGES_PER_REQ]; 279 280 /** number of pages in vector */ 281 unsigned num_pages; 282 283 /** offset of data on first page */ 284 unsigned page_offset; 285 286 /** File used in the request (or NULL) */ 287 struct fuse_file *ff; 288 289 /** Inode used in the request or NULL */ 290 struct inode *inode; 291 292 /** Link on fi->writepages */ 293 struct list_head writepages_entry; 294 295 /** Request completion callback */ 296 void (*end)(struct fuse_conn *, struct fuse_req *); 297 298 /** Request is stolen from fuse_file->reserved_req */ 299 struct file *stolen_file; 300 }; 301 302 /** 303 * A Fuse connection. 304 * 305 * This structure is created, when the filesystem is mounted, and is 306 * destroyed, when the client device is closed and the filesystem is 307 * unmounted. 308 */ 309 struct fuse_conn { 310 /** Lock protecting accessess to members of this structure */ 311 spinlock_t lock; 312 313 /** Mutex protecting against directory alias creation */ 314 struct mutex inst_mutex; 315 316 /** Refcount */ 317 atomic_t count; 318 319 /** The user id for this mount */ 320 uid_t user_id; 321 322 /** The group id for this mount */ 323 gid_t group_id; 324 325 /** The fuse mount flags for this mount */ 326 unsigned flags; 327 328 /** Maximum read size */ 329 unsigned max_read; 330 331 /** Maximum write size */ 332 unsigned max_write; 333 334 /** Readers of the connection are waiting on this */ 335 wait_queue_head_t waitq; 336 337 /** The list of pending requests */ 338 struct list_head pending; 339 340 /** The list of requests being processed */ 341 struct list_head processing; 342 343 /** The list of requests under I/O */ 344 struct list_head io; 345 346 /** The next unique kernel file handle */ 347 u64 khctr; 348 349 /** rbtree of fuse_files waiting for poll events indexed by ph */ 350 struct rb_root polled_files; 351 352 /** Number of requests currently in the background */ 353 unsigned num_background; 354 355 /** Number of background requests currently queued for userspace */ 356 unsigned active_background; 357 358 /** The list of background requests set aside for later queuing */ 359 struct list_head bg_queue; 360 361 /** Pending interrupts */ 362 struct list_head interrupts; 363 364 /** Flag indicating if connection is blocked. This will be 365 the case before the INIT reply is received, and if there 366 are too many outstading backgrounds requests */ 367 int blocked; 368 369 /** waitq for blocked connection */ 370 wait_queue_head_t blocked_waitq; 371 372 /** waitq for reserved requests */ 373 wait_queue_head_t reserved_req_waitq; 374 375 /** The next unique request id */ 376 u64 reqctr; 377 378 /** Connection established, cleared on umount, connection 379 abort and device release */ 380 unsigned connected; 381 382 /** Connection failed (version mismatch). Cannot race with 383 setting other bitfields since it is only set once in INIT 384 reply, before any other request, and never cleared */ 385 unsigned conn_error:1; 386 387 /** Connection successful. Only set in INIT */ 388 unsigned conn_init:1; 389 390 /** Do readpages asynchronously? Only set in INIT */ 391 unsigned async_read:1; 392 393 /** Do not send separate SETATTR request before open(O_TRUNC) */ 394 unsigned atomic_o_trunc:1; 395 396 /** Filesystem supports NFS exporting. Only set in INIT */ 397 unsigned export_support:1; 398 399 /** Set if bdi is valid */ 400 unsigned bdi_initialized:1; 401 402 /* 403 * The following bitfields are only for optimization purposes 404 * and hence races in setting them will not cause malfunction 405 */ 406 407 /** Is fsync not implemented by fs? */ 408 unsigned no_fsync:1; 409 410 /** Is fsyncdir not implemented by fs? */ 411 unsigned no_fsyncdir:1; 412 413 /** Is flush not implemented by fs? */ 414 unsigned no_flush:1; 415 416 /** Is setxattr not implemented by fs? */ 417 unsigned no_setxattr:1; 418 419 /** Is getxattr not implemented by fs? */ 420 unsigned no_getxattr:1; 421 422 /** Is listxattr not implemented by fs? */ 423 unsigned no_listxattr:1; 424 425 /** Is removexattr not implemented by fs? */ 426 unsigned no_removexattr:1; 427 428 /** Are file locking primitives not implemented by fs? */ 429 unsigned no_lock:1; 430 431 /** Is access not implemented by fs? */ 432 unsigned no_access:1; 433 434 /** Is create not implemented by fs? */ 435 unsigned no_create:1; 436 437 /** Is interrupt not implemented by fs? */ 438 unsigned no_interrupt:1; 439 440 /** Is bmap not implemented by fs? */ 441 unsigned no_bmap:1; 442 443 /** Is poll not implemented by fs? */ 444 unsigned no_poll:1; 445 446 /** Do multi-page cached writes */ 447 unsigned big_writes:1; 448 449 /** Don't apply umask to creation modes */ 450 unsigned dont_mask:1; 451 452 /** The number of requests waiting for completion */ 453 atomic_t num_waiting; 454 455 /** Negotiated minor version */ 456 unsigned minor; 457 458 /** Backing dev info */ 459 struct backing_dev_info bdi; 460 461 /** Entry on the fuse_conn_list */ 462 struct list_head entry; 463 464 /** Device ID from super block */ 465 dev_t dev; 466 467 /** Dentries in the control filesystem */ 468 struct dentry *ctl_dentry[FUSE_CTL_NUM_DENTRIES]; 469 470 /** number of dentries used in the above array */ 471 int ctl_ndents; 472 473 /** O_ASYNC requests */ 474 struct fasync_struct *fasync; 475 476 /** Key for lock owner ID scrambling */ 477 u32 scramble_key[4]; 478 479 /** Reserved request for the DESTROY message */ 480 struct fuse_req *destroy_req; 481 482 /** Version counter for attribute changes */ 483 u64 attr_version; 484 485 /** Called on final put */ 486 void (*release)(struct fuse_conn *); 487 488 /** Super block for this connection. */ 489 struct super_block *sb; 490 491 /** Read/write semaphore to hold when accessing sb. */ 492 struct rw_semaphore killsb; 493 }; 494 495 static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb) 496 { 497 return sb->s_fs_info; 498 } 499 500 static inline struct fuse_conn *get_fuse_conn(struct inode *inode) 501 { 502 return get_fuse_conn_super(inode->i_sb); 503 } 504 505 static inline struct fuse_inode *get_fuse_inode(struct inode *inode) 506 { 507 return container_of(inode, struct fuse_inode, inode); 508 } 509 510 static inline u64 get_node_id(struct inode *inode) 511 { 512 return get_fuse_inode(inode)->nodeid; 513 } 514 515 /** Device operations */ 516 extern const struct file_operations fuse_dev_operations; 517 518 extern const struct dentry_operations fuse_dentry_operations; 519 520 /** 521 * Inode to nodeid comparison. 522 */ 523 int fuse_inode_eq(struct inode *inode, void *_nodeidp); 524 525 /** 526 * Get a filled in inode 527 */ 528 struct inode *fuse_iget(struct super_block *sb, u64 nodeid, 529 int generation, struct fuse_attr *attr, 530 u64 attr_valid, u64 attr_version); 531 532 int fuse_lookup_name(struct super_block *sb, u64 nodeid, struct qstr *name, 533 struct fuse_entry_out *outarg, struct inode **inode); 534 535 /** 536 * Send FORGET command 537 */ 538 void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req, 539 u64 nodeid, u64 nlookup); 540 541 /** 542 * Initialize READ or READDIR request 543 */ 544 void fuse_read_fill(struct fuse_req *req, struct file *file, 545 loff_t pos, size_t count, int opcode); 546 547 /** 548 * Send OPEN or OPENDIR request 549 */ 550 int fuse_open_common(struct inode *inode, struct file *file, bool isdir); 551 552 struct fuse_file *fuse_file_alloc(struct fuse_conn *fc); 553 struct fuse_file *fuse_file_get(struct fuse_file *ff); 554 void fuse_file_free(struct fuse_file *ff); 555 void fuse_finish_open(struct inode *inode, struct file *file); 556 557 void fuse_sync_release(struct fuse_file *ff, int flags); 558 559 /** 560 * Send RELEASE or RELEASEDIR request 561 */ 562 void fuse_release_common(struct file *file, int opcode); 563 564 /** 565 * Send FSYNC or FSYNCDIR request 566 */ 567 int fuse_fsync_common(struct file *file, struct dentry *de, int datasync, 568 int isdir); 569 570 /** 571 * Notify poll wakeup 572 */ 573 int fuse_notify_poll_wakeup(struct fuse_conn *fc, 574 struct fuse_notify_poll_wakeup_out *outarg); 575 576 /** 577 * Initialize file operations on a regular file 578 */ 579 void fuse_init_file_inode(struct inode *inode); 580 581 /** 582 * Initialize inode operations on regular files and special files 583 */ 584 void fuse_init_common(struct inode *inode); 585 586 /** 587 * Initialize inode and file operations on a directory 588 */ 589 void fuse_init_dir(struct inode *inode); 590 591 /** 592 * Initialize inode operations on a symlink 593 */ 594 void fuse_init_symlink(struct inode *inode); 595 596 /** 597 * Change attributes of an inode 598 */ 599 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr, 600 u64 attr_valid, u64 attr_version); 601 602 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr, 603 u64 attr_valid); 604 605 void fuse_truncate(struct address_space *mapping, loff_t offset); 606 607 /** 608 * Initialize the client device 609 */ 610 int fuse_dev_init(void); 611 612 /** 613 * Cleanup the client device 614 */ 615 void fuse_dev_cleanup(void); 616 617 int fuse_ctl_init(void); 618 void fuse_ctl_cleanup(void); 619 620 /** 621 * Allocate a request 622 */ 623 struct fuse_req *fuse_request_alloc(void); 624 625 struct fuse_req *fuse_request_alloc_nofs(void); 626 627 /** 628 * Free a request 629 */ 630 void fuse_request_free(struct fuse_req *req); 631 632 /** 633 * Get a request, may fail with -ENOMEM 634 */ 635 struct fuse_req *fuse_get_req(struct fuse_conn *fc); 636 637 /** 638 * Gets a requests for a file operation, always succeeds 639 */ 640 struct fuse_req *fuse_get_req_nofail(struct fuse_conn *fc, struct file *file); 641 642 /** 643 * Decrement reference count of a request. If count goes to zero free 644 * the request. 645 */ 646 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req); 647 648 /** 649 * Send a request (synchronous) 650 */ 651 void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req); 652 653 /** 654 * Send a request with no reply 655 */ 656 void fuse_request_send_noreply(struct fuse_conn *fc, struct fuse_req *req); 657 658 /** 659 * Send a request in the background 660 */ 661 void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req); 662 663 void fuse_request_send_background_locked(struct fuse_conn *fc, 664 struct fuse_req *req); 665 666 /* Abort all requests */ 667 void fuse_abort_conn(struct fuse_conn *fc); 668 669 /** 670 * Invalidate inode attributes 671 */ 672 void fuse_invalidate_attr(struct inode *inode); 673 674 void fuse_invalidate_entry_cache(struct dentry *entry); 675 676 /** 677 * Acquire reference to fuse_conn 678 */ 679 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc); 680 681 void fuse_conn_kill(struct fuse_conn *fc); 682 683 /** 684 * Initialize fuse_conn 685 */ 686 void fuse_conn_init(struct fuse_conn *fc); 687 688 /** 689 * Release reference to fuse_conn 690 */ 691 void fuse_conn_put(struct fuse_conn *fc); 692 693 /** 694 * Add connection to control filesystem 695 */ 696 int fuse_ctl_add_conn(struct fuse_conn *fc); 697 698 /** 699 * Remove connection from control filesystem 700 */ 701 void fuse_ctl_remove_conn(struct fuse_conn *fc); 702 703 /** 704 * Is file type valid? 705 */ 706 int fuse_valid_type(int m); 707 708 /** 709 * Is task allowed to perform filesystem operation? 710 */ 711 int fuse_allow_task(struct fuse_conn *fc, struct task_struct *task); 712 713 u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id); 714 715 int fuse_update_attributes(struct inode *inode, struct kstat *stat, 716 struct file *file, bool *refreshed); 717 718 void fuse_flush_writepages(struct inode *inode); 719 720 void fuse_set_nowrite(struct inode *inode); 721 void fuse_release_nowrite(struct inode *inode); 722 723 u64 fuse_get_attr_version(struct fuse_conn *fc); 724 725 /** 726 * File-system tells the kernel to invalidate cache for the given node id. 727 */ 728 int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid, 729 loff_t offset, loff_t len); 730 731 /** 732 * File-system tells the kernel to invalidate parent attributes and 733 * the dentry matching parent/name. 734 */ 735 int fuse_reverse_inval_entry(struct super_block *sb, u64 parent_nodeid, 736 struct qstr *name); 737 738 int fuse_do_open(struct fuse_conn *fc, u64 nodeid, struct file *file, 739 bool isdir); 740 ssize_t fuse_direct_io(struct file *file, const char __user *buf, 741 size_t count, loff_t *ppos, int write); 742 long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg, 743 unsigned int flags); 744 unsigned fuse_file_poll(struct file *file, poll_table *wait); 745 int fuse_dev_release(struct inode *inode, struct file *file); 746 747 #endif /* _FS_FUSE_I_H */ 748