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 { 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 /** Number of requests currently in the background */ 351 unsigned num_background; 352 353 /** Number of background requests currently queued for userspace */ 354 unsigned active_background; 355 356 /** The list of background requests set aside for later queuing */ 357 struct list_head bg_queue; 358 359 /** Pending interrupts */ 360 struct list_head interrupts; 361 362 /** Flag indicating if connection is blocked. This will be 363 the case before the INIT reply is received, and if there 364 are too many outstading backgrounds requests */ 365 int blocked; 366 367 /** waitq for blocked connection */ 368 wait_queue_head_t blocked_waitq; 369 370 /** waitq for reserved requests */ 371 wait_queue_head_t reserved_req_waitq; 372 373 /** The next unique request id */ 374 u64 reqctr; 375 376 /** Connection established, cleared on umount, connection 377 abort and device release */ 378 unsigned connected; 379 380 /** Connection failed (version mismatch). Cannot race with 381 setting other bitfields since it is only set once in INIT 382 reply, before any other request, and never cleared */ 383 unsigned conn_error:1; 384 385 /** Connection successful. Only set in INIT */ 386 unsigned conn_init:1; 387 388 /** Do readpages asynchronously? Only set in INIT */ 389 unsigned async_read:1; 390 391 /** Do not send separate SETATTR request before open(O_TRUNC) */ 392 unsigned atomic_o_trunc:1; 393 394 /** Filesystem supports NFS exporting. Only set in INIT */ 395 unsigned export_support:1; 396 397 /* 398 * The following bitfields are only for optimization purposes 399 * and hence races in setting them will not cause malfunction 400 */ 401 402 /** Is fsync not implemented by fs? */ 403 unsigned no_fsync:1; 404 405 /** Is fsyncdir not implemented by fs? */ 406 unsigned no_fsyncdir:1; 407 408 /** Is flush not implemented by fs? */ 409 unsigned no_flush:1; 410 411 /** Is setxattr not implemented by fs? */ 412 unsigned no_setxattr:1; 413 414 /** Is getxattr not implemented by fs? */ 415 unsigned no_getxattr:1; 416 417 /** Is listxattr not implemented by fs? */ 418 unsigned no_listxattr:1; 419 420 /** Is removexattr not implemented by fs? */ 421 unsigned no_removexattr:1; 422 423 /** Are file locking primitives not implemented by fs? */ 424 unsigned no_lock:1; 425 426 /** Is access not implemented by fs? */ 427 unsigned no_access:1; 428 429 /** Is create not implemented by fs? */ 430 unsigned no_create:1; 431 432 /** Is interrupt not implemented by fs? */ 433 unsigned no_interrupt:1; 434 435 /** Is bmap not implemented by fs? */ 436 unsigned no_bmap:1; 437 438 /** Is poll not implemented by fs? */ 439 unsigned no_poll:1; 440 441 /** Do multi-page cached writes */ 442 unsigned big_writes:1; 443 444 /** The number of requests waiting for completion */ 445 atomic_t num_waiting; 446 447 /** Negotiated minor version */ 448 unsigned minor; 449 450 /** Backing dev info */ 451 struct backing_dev_info bdi; 452 453 /** Entry on the fuse_conn_list */ 454 struct list_head entry; 455 456 /** Device ID from super block */ 457 dev_t dev; 458 459 /** Dentries in the control filesystem */ 460 struct dentry *ctl_dentry[FUSE_CTL_NUM_DENTRIES]; 461 462 /** number of dentries used in the above array */ 463 int ctl_ndents; 464 465 /** O_ASYNC requests */ 466 struct fasync_struct *fasync; 467 468 /** Key for lock owner ID scrambling */ 469 u32 scramble_key[4]; 470 471 /** Reserved request for the DESTROY message */ 472 struct fuse_req *destroy_req; 473 474 /** Version counter for attribute changes */ 475 u64 attr_version; 476 477 /** Called on final put */ 478 void (*release)(struct fuse_conn *); 479 }; 480 481 static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb) 482 { 483 return sb->s_fs_info; 484 } 485 486 static inline struct fuse_conn *get_fuse_conn(struct inode *inode) 487 { 488 return get_fuse_conn_super(inode->i_sb); 489 } 490 491 static inline struct fuse_inode *get_fuse_inode(struct inode *inode) 492 { 493 return container_of(inode, struct fuse_inode, inode); 494 } 495 496 static inline u64 get_node_id(struct inode *inode) 497 { 498 return get_fuse_inode(inode)->nodeid; 499 } 500 501 /** Device operations */ 502 extern const struct file_operations fuse_dev_operations; 503 504 extern const struct dentry_operations fuse_dentry_operations; 505 506 /** 507 * Get a filled in inode 508 */ 509 struct inode *fuse_iget(struct super_block *sb, u64 nodeid, 510 int generation, struct fuse_attr *attr, 511 u64 attr_valid, u64 attr_version); 512 513 int fuse_lookup_name(struct super_block *sb, u64 nodeid, struct qstr *name, 514 struct fuse_entry_out *outarg, struct inode **inode); 515 516 /** 517 * Send FORGET command 518 */ 519 void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req, 520 u64 nodeid, u64 nlookup); 521 522 /** 523 * Initialize READ or READDIR request 524 */ 525 void fuse_read_fill(struct fuse_req *req, struct file *file, 526 loff_t pos, size_t count, int opcode); 527 528 /** 529 * Send OPEN or OPENDIR request 530 */ 531 int fuse_open_common(struct inode *inode, struct file *file, int isdir); 532 533 struct fuse_file *fuse_file_alloc(struct fuse_conn *fc); 534 struct fuse_file *fuse_file_get(struct fuse_file *ff); 535 void fuse_file_free(struct fuse_file *ff); 536 void fuse_finish_open(struct inode *inode, struct file *file); 537 538 /** Fill in ff->reserved_req with a RELEASE request */ 539 void fuse_release_fill(struct fuse_file *ff, int flags, int opcode); 540 541 /** 542 * Send RELEASE or RELEASEDIR request 543 */ 544 int fuse_release_common(struct inode *inode, struct file *file, int isdir); 545 546 /** 547 * Send FSYNC or FSYNCDIR request 548 */ 549 int fuse_fsync_common(struct file *file, struct dentry *de, int datasync, 550 int isdir); 551 552 /** 553 * Notify poll wakeup 554 */ 555 int fuse_notify_poll_wakeup(struct fuse_conn *fc, 556 struct fuse_notify_poll_wakeup_out *outarg); 557 558 /** 559 * Initialize file operations on a regular file 560 */ 561 void fuse_init_file_inode(struct inode *inode); 562 563 /** 564 * Initialize inode operations on regular files and special files 565 */ 566 void fuse_init_common(struct inode *inode); 567 568 /** 569 * Initialize inode and file operations on a directory 570 */ 571 void fuse_init_dir(struct inode *inode); 572 573 /** 574 * Initialize inode operations on a symlink 575 */ 576 void fuse_init_symlink(struct inode *inode); 577 578 /** 579 * Change attributes of an inode 580 */ 581 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr, 582 u64 attr_valid, u64 attr_version); 583 584 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr, 585 u64 attr_valid); 586 587 void fuse_truncate(struct address_space *mapping, loff_t offset); 588 589 /** 590 * Initialize the client device 591 */ 592 int fuse_dev_init(void); 593 594 /** 595 * Cleanup the client device 596 */ 597 void fuse_dev_cleanup(void); 598 599 int fuse_ctl_init(void); 600 void fuse_ctl_cleanup(void); 601 602 /** 603 * Allocate a request 604 */ 605 struct fuse_req *fuse_request_alloc(void); 606 607 struct fuse_req *fuse_request_alloc_nofs(void); 608 609 /** 610 * Free a request 611 */ 612 void fuse_request_free(struct fuse_req *req); 613 614 /** 615 * Get a request, may fail with -ENOMEM 616 */ 617 struct fuse_req *fuse_get_req(struct fuse_conn *fc); 618 619 /** 620 * Gets a requests for a file operation, always succeeds 621 */ 622 struct fuse_req *fuse_get_req_nofail(struct fuse_conn *fc, struct file *file); 623 624 /** 625 * Decrement reference count of a request. If count goes to zero free 626 * the request. 627 */ 628 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req); 629 630 /** 631 * Send a request (synchronous) 632 */ 633 void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req); 634 635 /** 636 * Send a request with no reply 637 */ 638 void fuse_request_send_noreply(struct fuse_conn *fc, struct fuse_req *req); 639 640 /** 641 * Send a request in the background 642 */ 643 void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req); 644 645 void fuse_request_send_background_locked(struct fuse_conn *fc, 646 struct fuse_req *req); 647 648 /* Abort all requests */ 649 void fuse_abort_conn(struct fuse_conn *fc); 650 651 /** 652 * Invalidate inode attributes 653 */ 654 void fuse_invalidate_attr(struct inode *inode); 655 656 void fuse_invalidate_entry_cache(struct dentry *entry); 657 658 /** 659 * Acquire reference to fuse_conn 660 */ 661 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc); 662 663 /** 664 * Initialize fuse_conn 665 */ 666 int fuse_conn_init(struct fuse_conn *fc, struct super_block *sb); 667 668 /** 669 * Release reference to fuse_conn 670 */ 671 void fuse_conn_put(struct fuse_conn *fc); 672 673 /** 674 * Add connection to control filesystem 675 */ 676 int fuse_ctl_add_conn(struct fuse_conn *fc); 677 678 /** 679 * Remove connection from control filesystem 680 */ 681 void fuse_ctl_remove_conn(struct fuse_conn *fc); 682 683 /** 684 * Is file type valid? 685 */ 686 int fuse_valid_type(int m); 687 688 /** 689 * Is task allowed to perform filesystem operation? 690 */ 691 int fuse_allow_task(struct fuse_conn *fc, struct task_struct *task); 692 693 u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id); 694 695 int fuse_update_attributes(struct inode *inode, struct kstat *stat, 696 struct file *file, bool *refreshed); 697 698 void fuse_flush_writepages(struct inode *inode); 699 700 void fuse_set_nowrite(struct inode *inode); 701 void fuse_release_nowrite(struct inode *inode); 702 703 u64 fuse_get_attr_version(struct fuse_conn *fc); 704 705 #endif /* _FS_FUSE_I_H */ 706