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