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