fs/fuse/fuse_i.h

   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 */