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 /* One forget request */ 57 struct fuse_forget_link { 58 struct fuse_forget_one forget_one; 59 struct fuse_forget_link *next; 60 }; 61 62 /** FUSE inode */ 63 struct fuse_inode { 64 /** Inode data */ 65 struct inode inode; 66 67 /** Unique ID, which identifies the inode between userspace 68 * and kernel */ 69 u64 nodeid; 70 71 /** Number of lookups on this inode */ 72 u64 nlookup; 73 74 /** The request used for sending the FORGET message */ 75 struct fuse_forget_link *forget; 76 77 /** Time in jiffies until the file attributes are valid */ 78 u64 i_time; 79 80 /** The sticky bit in inode->i_mode may have been removed, so 81 preserve the original mode */ 82 mode_t orig_i_mode; 83 84 /** Version of last attribute change */ 85 u64 attr_version; 86 87 /** Files usable in writepage. Protected by fc->lock */ 88 struct list_head write_files; 89 90 /** Writepages pending on truncate or fsync */ 91 struct list_head queued_writes; 92 93 /** Number of sent writes, a negative bias (FUSE_NOWRITE) 94 * means more writes are blocked */ 95 int writectr; 96 97 /** Waitq for writepage completion */ 98 wait_queue_head_t page_waitq; 99 100 /** List of writepage requestst (pending or sent) */ 101 struct list_head writepages; 102 }; 103 104 struct fuse_conn; 105 106 /** FUSE specific file data */ 107 struct fuse_file { 108 /** Fuse connection for this file */ 109 struct fuse_conn *fc; 110 111 /** Request reserved for flush and release */ 112 struct fuse_req *reserved_req; 113 114 /** Kernel file handle guaranteed to be unique */ 115 u64 kh; 116 117 /** File handle used by userspace */ 118 u64 fh; 119 120 /** Node id of this file */ 121 u64 nodeid; 122 123 /** Refcount */ 124 atomic_t count; 125 126 /** FOPEN_* flags returned by open */ 127 u32 open_flags; 128 129 /** Entry on inode's write_files list */ 130 struct list_head write_entry; 131 132 /** RB node to be linked on fuse_conn->polled_files */ 133 struct rb_node polled_node; 134 135 /** Wait queue head for poll */ 136 wait_queue_head_t poll_wait; 137 }; 138 139 /** One input argument of a request */ 140 struct fuse_in_arg { 141 unsigned size; 142 const void *value; 143 }; 144 145 /** The request input */ 146 struct fuse_in { 147 /** The request header */ 148 struct fuse_in_header h; 149 150 /** True if the data for the last argument is in req->pages */ 151 unsigned argpages:1; 152 153 /** Number of arguments */ 154 unsigned numargs; 155 156 /** Array of arguments */ 157 struct fuse_in_arg args[3]; 158 }; 159 160 /** One output argument of a request */ 161 struct fuse_arg { 162 unsigned size; 163 void *value; 164 }; 165 166 /** The request output */ 167 struct fuse_out { 168 /** Header returned from userspace */ 169 struct fuse_out_header h; 170 171 /* 172 * The following bitfields are not changed during the request 173 * processing 174 */ 175 176 /** Last argument is variable length (can be shorter than 177 arg->size) */ 178 unsigned argvar:1; 179 180 /** Last argument is a list of pages to copy data to */ 181 unsigned argpages:1; 182 183 /** Zero partially or not copied pages */ 184 unsigned page_zeroing:1; 185 186 /** Pages may be replaced with new ones */ 187 unsigned page_replace:1; 188 189 /** Number or arguments */ 190 unsigned numargs; 191 192 /** Array of arguments */ 193 struct fuse_arg args[3]; 194 }; 195 196 /** The request state */ 197 enum fuse_req_state { 198 FUSE_REQ_INIT = 0, 199 FUSE_REQ_PENDING, 200 FUSE_REQ_READING, 201 FUSE_REQ_SENT, 202 FUSE_REQ_WRITING, 203 FUSE_REQ_FINISHED 204 }; 205 206 /** 207 * A request to the client 208 */ 209 struct fuse_req { 210 /** This can be on either pending processing or io lists in 211 fuse_conn */ 212 struct list_head list; 213 214 /** Entry on the interrupts list */ 215 struct list_head intr_entry; 216 217 /** refcount */ 218 atomic_t count; 219 220 /** Unique ID for the interrupt request */ 221 u64 intr_unique; 222 223 /* 224 * The following bitfields are either set once before the 225 * request is queued or setting/clearing them is protected by 226 * fuse_conn->lock 227 */ 228 229 /** True if the request has reply */ 230 unsigned isreply:1; 231 232 /** Force sending of the request even if interrupted */ 233 unsigned force:1; 234 235 /** The request was aborted */ 236 unsigned aborted:1; 237 238 /** Request is sent in the background */ 239 unsigned background:1; 240 241 /** The request has been interrupted */ 242 unsigned interrupted:1; 243 244 /** Data is being copied to/from the request */ 245 unsigned locked:1; 246 247 /** Request is counted as "waiting" */ 248 unsigned waiting:1; 249 250 /** State of the request */ 251 enum fuse_req_state state; 252 253 /** The request input */ 254 struct fuse_in in; 255 256 /** The request output */ 257 struct fuse_out out; 258 259 /** Used to wake up the task waiting for completion of request*/ 260 wait_queue_head_t waitq; 261 262 /** Data for asynchronous requests */ 263 union { 264 struct { 265 struct fuse_release_in in; 266 struct path path; 267 } release; 268 struct fuse_init_in init_in; 269 struct fuse_init_out init_out; 270 struct cuse_init_in cuse_init_in; 271 struct cuse_init_out cuse_init_out; 272 struct { 273 struct fuse_read_in in; 274 u64 attr_ver; 275 } read; 276 struct { 277 struct fuse_write_in in; 278 struct fuse_write_out out; 279 } write; 280 struct fuse_notify_retrieve_in retrieve_in; 281 struct fuse_lk_in lk_in; 282 } misc; 283 284 /** page vector */ 285 struct page *pages[FUSE_MAX_PAGES_PER_REQ]; 286 287 /** number of pages in vector */ 288 unsigned num_pages; 289 290 /** offset of data on first page */ 291 unsigned page_offset; 292 293 /** File used in the request (or NULL) */ 294 struct fuse_file *ff; 295 296 /** Inode used in the request or NULL */ 297 struct inode *inode; 298 299 /** Link on fi->writepages */ 300 struct list_head writepages_entry; 301 302 /** Request completion callback */ 303 void (*end)(struct fuse_conn *, struct fuse_req *); 304 305 /** Request is stolen from fuse_file->reserved_req */ 306 struct file *stolen_file; 307 }; 308 309 /** 310 * A Fuse connection. 311 * 312 * This structure is created, when the filesystem is mounted, and is 313 * destroyed, when the client device is closed and the filesystem is 314 * unmounted. 315 */ 316 struct fuse_conn { 317 /** Lock protecting accessess to members of this structure */ 318 spinlock_t lock; 319 320 /** Mutex protecting against directory alias creation */ 321 struct mutex inst_mutex; 322 323 /** Refcount */ 324 atomic_t count; 325 326 /** The user id for this mount */ 327 uid_t user_id; 328 329 /** The group id for this mount */ 330 gid_t group_id; 331 332 /** The fuse mount flags for this mount */ 333 unsigned flags; 334 335 /** Maximum read size */ 336 unsigned max_read; 337 338 /** Maximum write size */ 339 unsigned max_write; 340 341 /** Readers of the connection are waiting on this */ 342 wait_queue_head_t waitq; 343 344 /** The list of pending requests */ 345 struct list_head pending; 346 347 /** The list of requests being processed */ 348 struct list_head processing; 349 350 /** The list of requests under I/O */ 351 struct list_head io; 352 353 /** The next unique kernel file handle */ 354 u64 khctr; 355 356 /** rbtree of fuse_files waiting for poll events indexed by ph */ 357 struct rb_root polled_files; 358 359 /** Maximum number of outstanding background requests */ 360 unsigned max_background; 361 362 /** Number of background requests at which congestion starts */ 363 unsigned congestion_threshold; 364 365 /** Number of requests currently in the background */ 366 unsigned num_background; 367 368 /** Number of background requests currently queued for userspace */ 369 unsigned active_background; 370 371 /** The list of background requests set aside for later queuing */ 372 struct list_head bg_queue; 373 374 /** Pending interrupts */ 375 struct list_head interrupts; 376 377 /** Queue of pending forgets */ 378 struct fuse_forget_link forget_list_head; 379 struct fuse_forget_link *forget_list_tail; 380 381 /** Batching of FORGET requests (positive indicates FORGET batch) */ 382 int forget_batch; 383 384 /** Flag indicating if connection is blocked. This will be 385 the case before the INIT reply is received, and if there 386 are too many outstading backgrounds requests */ 387 int blocked; 388 389 /** waitq for blocked connection */ 390 wait_queue_head_t blocked_waitq; 391 392 /** waitq for reserved requests */ 393 wait_queue_head_t reserved_req_waitq; 394 395 /** The next unique request id */ 396 u64 reqctr; 397 398 /** Connection established, cleared on umount, connection 399 abort and device release */ 400 unsigned connected; 401 402 /** Connection failed (version mismatch). Cannot race with 403 setting other bitfields since it is only set once in INIT 404 reply, before any other request, and never cleared */ 405 unsigned conn_error:1; 406 407 /** Connection successful. Only set in INIT */ 408 unsigned conn_init:1; 409 410 /** Do readpages asynchronously? Only set in INIT */ 411 unsigned async_read:1; 412 413 /** Do not send separate SETATTR request before open(O_TRUNC) */ 414 unsigned atomic_o_trunc:1; 415 416 /** Filesystem supports NFS exporting. Only set in INIT */ 417 unsigned export_support:1; 418 419 /** Set if bdi is valid */ 420 unsigned bdi_initialized:1; 421 422 /* 423 * The following bitfields are only for optimization purposes 424 * and hence races in setting them will not cause malfunction 425 */ 426 427 /** Is fsync not implemented by fs? */ 428 unsigned no_fsync:1; 429 430 /** Is fsyncdir not implemented by fs? */ 431 unsigned no_fsyncdir:1; 432 433 /** Is flush not implemented by fs? */ 434 unsigned no_flush:1; 435 436 /** Is setxattr not implemented by fs? */ 437 unsigned no_setxattr:1; 438 439 /** Is getxattr not implemented by fs? */ 440 unsigned no_getxattr:1; 441 442 /** Is listxattr not implemented by fs? */ 443 unsigned no_listxattr:1; 444 445 /** Is removexattr not implemented by fs? */ 446 unsigned no_removexattr:1; 447 448 /** Are file locking primitives not implemented by fs? */ 449 unsigned no_lock:1; 450 451 /** Is access not implemented by fs? */ 452 unsigned no_access:1; 453 454 /** Is create not implemented by fs? */ 455 unsigned no_create:1; 456 457 /** Is interrupt not implemented by fs? */ 458 unsigned no_interrupt:1; 459 460 /** Is bmap not implemented by fs? */ 461 unsigned no_bmap:1; 462 463 /** Is poll not implemented by fs? */ 464 unsigned no_poll:1; 465 466 /** Do multi-page cached writes */ 467 unsigned big_writes:1; 468 469 /** Don't apply umask to creation modes */ 470 unsigned dont_mask:1; 471 472 /** The number of requests waiting for completion */ 473 atomic_t num_waiting; 474 475 /** Negotiated minor version */ 476 unsigned minor; 477 478 /** Backing dev info */ 479 struct backing_dev_info bdi; 480 481 /** Entry on the fuse_conn_list */ 482 struct list_head entry; 483 484 /** Device ID from super block */ 485 dev_t dev; 486 487 /** Dentries in the control filesystem */ 488 struct dentry *ctl_dentry[FUSE_CTL_NUM_DENTRIES]; 489 490 /** number of dentries used in the above array */ 491 int ctl_ndents; 492 493 /** O_ASYNC requests */ 494 struct fasync_struct *fasync; 495 496 /** Key for lock owner ID scrambling */ 497 u32 scramble_key[4]; 498 499 /** Reserved request for the DESTROY message */ 500 struct fuse_req *destroy_req; 501 502 /** Version counter for attribute changes */ 503 u64 attr_version; 504 505 /** Called on final put */ 506 void (*release)(struct fuse_conn *); 507 508 /** Super block for this connection. */ 509 struct super_block *sb; 510 511 /** Read/write semaphore to hold when accessing sb. */ 512 struct rw_semaphore killsb; 513 }; 514 515 static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb) 516 { 517 return sb->s_fs_info; 518 } 519 520 static inline struct fuse_conn *get_fuse_conn(struct inode *inode) 521 { 522 return get_fuse_conn_super(inode->i_sb); 523 } 524 525 static inline struct fuse_inode *get_fuse_inode(struct inode *inode) 526 { 527 return container_of(inode, struct fuse_inode, inode); 528 } 529 530 static inline u64 get_node_id(struct inode *inode) 531 { 532 return get_fuse_inode(inode)->nodeid; 533 } 534 535 /** Device operations */ 536 extern const struct file_operations fuse_dev_operations; 537 538 extern const struct dentry_operations fuse_dentry_operations; 539 540 /** 541 * Inode to nodeid comparison. 542 */ 543 int fuse_inode_eq(struct inode *inode, void *_nodeidp); 544 545 /** 546 * Get a filled in inode 547 */ 548 struct inode *fuse_iget(struct super_block *sb, u64 nodeid, 549 int generation, struct fuse_attr *attr, 550 u64 attr_valid, u64 attr_version); 551 552 int fuse_lookup_name(struct super_block *sb, u64 nodeid, struct qstr *name, 553 struct fuse_entry_out *outarg, struct inode **inode); 554 555 /** 556 * Send FORGET command 557 */ 558 void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget, 559 u64 nodeid, u64 nlookup); 560 561 struct fuse_forget_link *fuse_alloc_forget(void); 562 563 /** 564 * Initialize READ or READDIR request 565 */ 566 void fuse_read_fill(struct fuse_req *req, struct file *file, 567 loff_t pos, size_t count, int opcode); 568 569 /** 570 * Send OPEN or OPENDIR request 571 */ 572 int fuse_open_common(struct inode *inode, struct file *file, bool isdir); 573 574 struct fuse_file *fuse_file_alloc(struct fuse_conn *fc); 575 struct fuse_file *fuse_file_get(struct fuse_file *ff); 576 void fuse_file_free(struct fuse_file *ff); 577 void fuse_finish_open(struct inode *inode, struct file *file); 578 579 void fuse_sync_release(struct fuse_file *ff, int flags); 580 581 /** 582 * Send RELEASE or RELEASEDIR request 583 */ 584 void fuse_release_common(struct file *file, int opcode); 585 586 /** 587 * Send FSYNC or FSYNCDIR request 588 */ 589 int fuse_fsync_common(struct file *file, int datasync, int isdir); 590 591 /** 592 * Notify poll wakeup 593 */ 594 int fuse_notify_poll_wakeup(struct fuse_conn *fc, 595 struct fuse_notify_poll_wakeup_out *outarg); 596 597 /** 598 * Initialize file operations on a regular file 599 */ 600 void fuse_init_file_inode(struct inode *inode); 601 602 /** 603 * Initialize inode operations on regular files and special files 604 */ 605 void fuse_init_common(struct inode *inode); 606 607 /** 608 * Initialize inode and file operations on a directory 609 */ 610 void fuse_init_dir(struct inode *inode); 611 612 /** 613 * Initialize inode operations on a symlink 614 */ 615 void fuse_init_symlink(struct inode *inode); 616 617 /** 618 * Change attributes of an inode 619 */ 620 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr, 621 u64 attr_valid, u64 attr_version); 622 623 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr, 624 u64 attr_valid); 625 626 /** 627 * Initialize the client device 628 */ 629 int fuse_dev_init(void); 630 631 /** 632 * Cleanup the client device 633 */ 634 void fuse_dev_cleanup(void); 635 636 int fuse_ctl_init(void); 637 void fuse_ctl_cleanup(void); 638 639 /** 640 * Allocate a request 641 */ 642 struct fuse_req *fuse_request_alloc(void); 643 644 struct fuse_req *fuse_request_alloc_nofs(void); 645 646 /** 647 * Free a request 648 */ 649 void fuse_request_free(struct fuse_req *req); 650 651 /** 652 * Get a request, may fail with -ENOMEM 653 */ 654 struct fuse_req *fuse_get_req(struct fuse_conn *fc); 655 656 /** 657 * Gets a requests for a file operation, always succeeds 658 */ 659 struct fuse_req *fuse_get_req_nofail(struct fuse_conn *fc, struct file *file); 660 661 /** 662 * Decrement reference count of a request. If count goes to zero free 663 * the request. 664 */ 665 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req); 666 667 /** 668 * Send a request (synchronous) 669 */ 670 void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req); 671 672 /** 673 * Send a request in the background 674 */ 675 void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req); 676 677 void fuse_request_send_background_locked(struct fuse_conn *fc, 678 struct fuse_req *req); 679 680 /* Abort all requests */ 681 void fuse_abort_conn(struct fuse_conn *fc); 682 683 /** 684 * Invalidate inode attributes 685 */ 686 void fuse_invalidate_attr(struct inode *inode); 687 688 void fuse_invalidate_entry_cache(struct dentry *entry); 689 690 /** 691 * Acquire reference to fuse_conn 692 */ 693 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc); 694 695 void fuse_conn_kill(struct fuse_conn *fc); 696 697 /** 698 * Initialize fuse_conn 699 */ 700 void fuse_conn_init(struct fuse_conn *fc); 701 702 /** 703 * Release reference to fuse_conn 704 */ 705 void fuse_conn_put(struct fuse_conn *fc); 706 707 /** 708 * Add connection to control filesystem 709 */ 710 int fuse_ctl_add_conn(struct fuse_conn *fc); 711 712 /** 713 * Remove connection from control filesystem 714 */ 715 void fuse_ctl_remove_conn(struct fuse_conn *fc); 716 717 /** 718 * Is file type valid? 719 */ 720 int fuse_valid_type(int m); 721 722 /** 723 * Is task allowed to perform filesystem operation? 724 */ 725 int fuse_allow_task(struct fuse_conn *fc, struct task_struct *task); 726 727 u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id); 728 729 int fuse_update_attributes(struct inode *inode, struct kstat *stat, 730 struct file *file, bool *refreshed); 731 732 void fuse_flush_writepages(struct inode *inode); 733 734 void fuse_set_nowrite(struct inode *inode); 735 void fuse_release_nowrite(struct inode *inode); 736 737 u64 fuse_get_attr_version(struct fuse_conn *fc); 738 739 /** 740 * File-system tells the kernel to invalidate cache for the given node id. 741 */ 742 int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid, 743 loff_t offset, loff_t len); 744 745 /** 746 * File-system tells the kernel to invalidate parent attributes and 747 * the dentry matching parent/name. 748 */ 749 int fuse_reverse_inval_entry(struct super_block *sb, u64 parent_nodeid, 750 struct qstr *name); 751 752 int fuse_do_open(struct fuse_conn *fc, u64 nodeid, struct file *file, 753 bool isdir); 754 ssize_t fuse_direct_io(struct file *file, const char __user *buf, 755 size_t count, loff_t *ppos, int write); 756 long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg, 757 unsigned int flags); 758 unsigned fuse_file_poll(struct file *file, poll_table *wait); 759 int fuse_dev_release(struct inode *inode, struct file *file); 760 761 void fuse_write_update_size(struct inode *inode, loff_t pos); 762 763 #endif /* _FS_FUSE_I_H */ 764