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 #include <linux/workqueue.h>
  25 #include <linux/kref.h>
  26
  27 /** Max number of pages that can be used in a single read request */
  28 #define FUSE_MAX_PAGES_PER_REQ 32
  29
  30 /** Bias for fi->writectr, meaning new writepages must not be sent */
  31 #define FUSE_NOWRITE INT_MIN
  32
  33 /** It could be as large as PATH_MAX, but would that have any uses? */
  34 #define FUSE_NAME_MAX 1024
  35
  36 /** Number of dentries for each connection in the control filesystem */
  37 #define FUSE_CTL_NUM_DENTRIES 5
  38
  39 /** If the FUSE_DEFAULT_PERMISSIONS flag is given, the filesystem
  40     module will check permissions based on the file mode.  Otherwise no
  41     permission checking is done in the kernel */
  42 #define FUSE_DEFAULT_PERMISSIONS (1 << 0)
  43
  44 /** If the FUSE_ALLOW_OTHER flag is given, then not only the user
  45     doing the mount will be allowed to access the filesystem */
  46 #define FUSE_ALLOW_OTHER         (1 << 1)
  47
  48 /** Number of page pointers embedded in fuse_req */
  49 #define FUSE_REQ_INLINE_PAGES 1
  50
  51 /** List of active connections */
  52 extern struct list_head fuse_conn_list;
  53
  54 /** Global mutex protecting fuse_conn_list and the control filesystem */
  55 extern struct mutex fuse_mutex;
  56
  57 /** Module parameters */
  58 extern unsigned max_user_bgreq;
  59 extern unsigned max_user_congthresh;
  60
  61 /* One forget request */
  62 struct fuse_forget_link {
  63         struct fuse_forget_one forget_one;
  64         struct fuse_forget_link *next;
  65 };
  66
  67 /** FUSE inode */
  68 struct fuse_inode {
  69         /** Inode data */
  70         struct inode inode;
  71
  72         /** Unique ID, which identifies the inode between userspace
  73          * and kernel */
  74         u64 nodeid;
  75
  76         /** Number of lookups on this inode */
  77         u64 nlookup;
  78
  79         /** The request used for sending the FORGET message */
  80         struct fuse_forget_link *forget;
  81
  82         /** Time in jiffies until the file attributes are valid */
  83         u64 i_time;
  84
  85         /** The sticky bit in inode->i_mode may have been removed, so
  86             preserve the original mode */
  87         umode_t orig_i_mode;
  88
  89         /** 64 bit inode number */
  90         u64 orig_ino;
  91
  92         /** Version of last attribute change */
  93         u64 attr_version;
  94
  95         /** Files usable in writepage.  Protected by fc->lock */
  96         struct list_head write_files;
  97
  98         /** Writepages pending on truncate or fsync */
  99         struct list_head queued_writes;
 100
 101         /** Number of sent writes, a negative bias (FUSE_NOWRITE)
 102          * means more writes are blocked */
 103         int writectr;
 104
 105         /** Waitq for writepage completion */
 106         wait_queue_head_t page_waitq;
 107
 108         /** List of writepage requestst (pending or sent) */
 109         struct list_head writepages;
 110
 111         /** Miscellaneous bits describing inode state */
 112         unsigned long state;
 113
 114         /** Lock for serializing lookup and readdir for back compatibility*/
 115         struct mutex mutex;
 116 };
 117
 118 /** FUSE inode state bits */
 119 enum {
 120         /** Advise readdirplus  */
 121         FUSE_I_ADVISE_RDPLUS,
 122         /** Initialized with readdirplus */
 123         FUSE_I_INIT_RDPLUS,
 124         /** An operation changing file size is in progress  */
 125         FUSE_I_SIZE_UNSTABLE,
 126 };
 127
 128 struct fuse_conn;
 129
 130 /** FUSE specific file data */
 131 struct fuse_file {
 132         /** Fuse connection for this file */
 133         struct fuse_conn *fc;
 134
 135         /** Request reserved for flush and release */
 136         struct fuse_req *reserved_req;
 137
 138         /** Kernel file handle guaranteed to be unique */
 139         u64 kh;
 140
 141         /** File handle used by userspace */
 142         u64 fh;
 143
 144         /** Node id of this file */
 145         u64 nodeid;
 146
 147         /** Refcount */
 148         atomic_t count;
 149
 150         /** FOPEN_* flags returned by open */
 151         u32 open_flags;
 152
 153         /** Entry on inode's write_files list */
 154         struct list_head write_entry;
 155
 156         /** RB node to be linked on fuse_conn->polled_files */
 157         struct rb_node polled_node;
 158
 159         /** Wait queue head for poll */
 160         wait_queue_head_t poll_wait;
 161
 162         /** Has flock been performed on this file? */
 163         bool flock:1;
 164 };
 165
 166 /** One input argument of a request */
 167 struct fuse_in_arg {
 168         unsigned size;
 169         const void *value;
 170 };
 171
 172 /** The request input */
 173 struct fuse_in {
 174         /** The request header */
 175         struct fuse_in_header h;
 176
 177         /** True if the data for the last argument is in req->pages */
 178         unsigned argpages:1;
 179
 180         /** Number of arguments */
 181         unsigned numargs;
 182
 183         /** Array of arguments */
 184         struct fuse_in_arg args[3];
 185 };
 186
 187 /** One output argument of a request */
 188 struct fuse_arg {
 189         unsigned size;
 190         void *value;
 191 };
 192
 193 /** The request output */
 194 struct fuse_out {
 195         /** Header returned from userspace */
 196         struct fuse_out_header h;
 197
 198         /*
 199          * The following bitfields are not changed during the request
 200          * processing
 201          */
 202
 203         /** Last argument is variable length (can be shorter than
 204             arg->size) */
 205         unsigned argvar:1;
 206
 207         /** Last argument is a list of pages to copy data to */
 208         unsigned argpages:1;
 209
 210         /** Zero partially or not copied pages */
 211         unsigned page_zeroing:1;
 212
 213         /** Pages may be replaced with new ones */
 214         unsigned page_replace:1;
 215
 216         /** Number or arguments */
 217         unsigned numargs;
 218
 219         /** Array of arguments */
 220         struct fuse_arg args[2];
 221 };
 222
 223 /** FUSE page descriptor */
 224 struct fuse_page_desc {
 225         unsigned int length;
 226         unsigned int offset;
 227 };
 228
 229 struct fuse_args {
 230         struct {
 231                 struct {
 232                         uint32_t opcode;
 233                         uint64_t nodeid;
 234                 } h;
 235                 unsigned numargs;
 236                 struct fuse_in_arg args[3];
 237
 238         } in;
 239         struct {
 240                 unsigned argvar:1;
 241                 unsigned numargs;
 242                 struct fuse_arg args[2];
 243         } out;
 244 };
 245
 246 #define FUSE_ARGS(args) struct fuse_args args = {}
 247
 248 /** The request IO state (for asynchronous processing) */
 249 struct fuse_io_priv {
 250         struct kref refcnt;
 251         int async;
 252         spinlock_t lock;
 253         unsigned reqs;
 254         ssize_t bytes;
 255         size_t size;
 256         __u64 offset;
 257         bool write;
 258         int err;
 259         struct kiocb *iocb;
 260         struct file *file;
 261         struct completion *done;
 262 };
 263
 264 #define FUSE_IO_PRIV_SYNC(f) \
 265 {                                       \
 266         .refcnt = { ATOMIC_INIT(1) },   \
 267         .async = 0,                     \
 268         .file = f,                      \
 269 }
 270
 271 /**
 272  * Request flags
 273  *
 274  * FR_ISREPLY:          set if the request has reply
 275  * FR_FORCE:            force sending of the request even if interrupted
 276  * FR_BACKGROUND:       request is sent in the background
 277  * FR_WAITING:          request is counted as "waiting"
 278  * FR_ABORTED:          the request was aborted
 279  * FR_INTERRUPTED:      the request has been interrupted
 280  * FR_LOCKED:           data is being copied to/from the request
 281  * FR_PENDING:          request is not yet in userspace
 282  * FR_SENT:             request is in userspace, waiting for an answer
 283  * FR_FINISHED:         request is finished
 284  * FR_PRIVATE:          request is on private list
 285  */
 286 enum fuse_req_flag {
 287         FR_ISREPLY,
 288         FR_FORCE,
 289         FR_BACKGROUND,
 290         FR_WAITING,
 291         FR_ABORTED,
 292         FR_INTERRUPTED,
 293         FR_LOCKED,
 294         FR_PENDING,
 295         FR_SENT,
 296         FR_FINISHED,
 297         FR_PRIVATE,
 298 };
 299
 300 /**
 301  * A request to the client
 302  *
 303  * .waitq.lock protects the following fields:
 304  *   - FR_ABORTED
 305  *   - FR_LOCKED (may also be modified under fc->lock, tested under both)
 306  */
 307 struct fuse_req {
 308         /** This can be on either pending processing or io lists in
 309             fuse_conn */
 310         struct list_head list;
 311
 312         /** Entry on the interrupts list  */
 313         struct list_head intr_entry;
 314
 315         /** refcount */
 316         atomic_t count;
 317
 318         /** Unique ID for the interrupt request */
 319         u64 intr_unique;
 320
 321         /* Request flags, updated with test/set/clear_bit() */
 322         unsigned long flags;
 323
 324         /** The request input */
 325         struct fuse_in in;
 326
 327         /** The request output */
 328         struct fuse_out out;
 329
 330         /** Used to wake up the task waiting for completion of request*/
 331         wait_queue_head_t waitq;
 332
 333         /** Data for asynchronous requests */
 334         union {
 335                 struct {
 336                         struct fuse_release_in in;
 337                         struct inode *inode;
 338                 } release;
 339                 struct fuse_init_in init_in;
 340                 struct fuse_init_out init_out;
 341                 struct cuse_init_in cuse_init_in;
 342                 struct {
 343                         struct fuse_read_in in;
 344                         u64 attr_ver;
 345                 } read;
 346                 struct {
 347                         struct fuse_write_in in;
 348                         struct fuse_write_out out;
 349                         struct fuse_req *next;
 350                 } write;
 351                 struct fuse_notify_retrieve_in retrieve_in;
 352         } misc;
 353
 354         /** page vector */
 355         struct page **pages;
 356
 357         /** page-descriptor vector */
 358         struct fuse_page_desc *page_descs;
 359
 360         /** size of the 'pages' array */
 361         unsigned max_pages;
 362
 363         /** inline page vector */
 364         struct page *inline_pages[FUSE_REQ_INLINE_PAGES];
 365
 366         /** inline page-descriptor vector */
 367         struct fuse_page_desc inline_page_descs[FUSE_REQ_INLINE_PAGES];
 368
 369         /** number of pages in vector */
 370         unsigned num_pages;
 371
 372         /** File used in the request (or NULL) */
 373         struct fuse_file *ff;
 374
 375         /** Inode used in the request or NULL */
 376         struct inode *inode;
 377
 378         /** AIO control block */
 379         struct fuse_io_priv *io;
 380
 381         /** Link on fi->writepages */
 382         struct list_head writepages_entry;
 383
 384         /** Request completion callback */
 385         void (*end)(struct fuse_conn *, struct fuse_req *);
 386
 387         /** Request is stolen from fuse_file->reserved_req */
 388         struct file *stolen_file;
 389 };
 390
 391 struct fuse_iqueue {
 392         /** Connection established */
 393         unsigned connected;
 394
 395         /** Readers of the connection are waiting on this */
 396         wait_queue_head_t waitq;
 397
 398         /** The next unique request id */
 399         u64 reqctr;
 400
 401         /** The list of pending requests */
 402         struct list_head pending;
 403
 404         /** Pending interrupts */
 405         struct list_head interrupts;
 406
 407         /** Queue of pending forgets */
 408         struct fuse_forget_link forget_list_head;
 409         struct fuse_forget_link *forget_list_tail;
 410
 411         /** Batching of FORGET requests (positive indicates FORGET batch) */
 412         int forget_batch;
 413
 414         /** O_ASYNC requests */
 415         struct fasync_struct *fasync;
 416 };
 417
 418 struct fuse_pqueue {
 419         /** Connection established */
 420         unsigned connected;
 421
 422         /** Lock protecting accessess to  members of this structure */
 423         spinlock_t lock;
 424
 425         /** The list of requests being processed */
 426         struct list_head processing;
 427
 428         /** The list of requests under I/O */
 429         struct list_head io;
 430 };
 431
 432 /**
 433  * Fuse device instance
 434  */
 435 struct fuse_dev {
 436         /** Fuse connection for this device */
 437         struct fuse_conn *fc;
 438
 439         /** Processing queue */
 440         struct fuse_pqueue pq;
 441
 442         /** list entry on fc->devices */
 443         struct list_head entry;
 444 };
 445
 446 /**
 447  * A Fuse connection.
 448  *
 449  * This structure is created, when the filesystem is mounted, and is
 450  * destroyed, when the client device is closed and the filesystem is
 451  * unmounted.
 452  */
 453 struct fuse_conn {
 454         /** Lock protecting accessess to  members of this structure */
 455         spinlock_t lock;
 456
 457         /** Refcount */
 458         atomic_t count;
 459
 460         /** Number of fuse_dev's */
 461         atomic_t dev_count;
 462
 463         struct rcu_head rcu;
 464
 465         /** The user id for this mount */
 466         kuid_t user_id;
 467
 468         /** The group id for this mount */
 469         kgid_t group_id;
 470
 471         /** The fuse mount flags for this mount */
 472         unsigned flags;
 473
 474         /** Maximum read size */
 475         unsigned max_read;
 476
 477         /** Maximum write size */
 478         unsigned max_write;
 479
 480         /** Input queue */
 481         struct fuse_iqueue iq;
 482
 483         /** The next unique kernel file handle */
 484         u64 khctr;
 485
 486         /** rbtree of fuse_files waiting for poll events indexed by ph */
 487         struct rb_root polled_files;
 488
 489         /** Maximum number of outstanding background requests */
 490         unsigned max_background;
 491
 492         /** Number of background requests at which congestion starts */
 493         unsigned congestion_threshold;
 494
 495         /** Number of requests currently in the background */
 496         unsigned num_background;
 497
 498         /** Number of background requests currently queued for userspace */
 499         unsigned active_background;
 500
 501         /** The list of background requests set aside for later queuing */
 502         struct list_head bg_queue;
 503
 504         /** Flag indicating that INIT reply has been received. Allocating
 505          * any fuse request will be suspended until the flag is set */
 506         int initialized;
 507
 508         /** Flag indicating if connection is blocked.  This will be
 509             the case before the INIT reply is received, and if there
 510             are too many outstading backgrounds requests */
 511         int blocked;
 512
 513         /** waitq for blocked connection */
 514         wait_queue_head_t blocked_waitq;
 515
 516         /** waitq for reserved requests */
 517         wait_queue_head_t reserved_req_waitq;
 518
 519         /** Connection established, cleared on umount, connection
 520             abort and device release */
 521         unsigned connected;
 522
 523         /** Connection failed (version mismatch).  Cannot race with
 524             setting other bitfields since it is only set once in INIT
 525             reply, before any other request, and never cleared */
 526         unsigned conn_error:1;
 527
 528         /** Connection successful.  Only set in INIT */
 529         unsigned conn_init:1;
 530
 531         /** Do readpages asynchronously?  Only set in INIT */
 532         unsigned async_read:1;
 533
 534         /** Do not send separate SETATTR request before open(O_TRUNC)  */
 535         unsigned atomic_o_trunc:1;
 536
 537         /** Filesystem supports NFS exporting.  Only set in INIT */
 538         unsigned export_support:1;
 539
 540         /** Set if bdi is valid */
 541         unsigned bdi_initialized:1;
 542
 543         /** write-back cache policy (default is write-through) */
 544         unsigned writeback_cache:1;
 545
 546         /** allow parallel lookups and readdir (default is serialized) */
 547         unsigned parallel_dirops:1;
 548
 549         /*
 550          * The following bitfields are only for optimization purposes
 551          * and hence races in setting them will not cause malfunction
 552          */
 553
 554         /** Is open/release not implemented by fs? */
 555         unsigned no_open:1;
 556
 557         /** Is fsync not implemented by fs? */
 558         unsigned no_fsync:1;
 559
 560         /** Is fsyncdir not implemented by fs? */
 561         unsigned no_fsyncdir:1;
 562
 563         /** Is flush not implemented by fs? */
 564         unsigned no_flush:1;
 565
 566         /** Is setxattr not implemented by fs? */
 567         unsigned no_setxattr:1;
 568
 569         /** Is getxattr not implemented by fs? */
 570         unsigned no_getxattr:1;
 571
 572         /** Is listxattr not implemented by fs? */
 573         unsigned no_listxattr:1;
 574
 575         /** Is removexattr not implemented by fs? */
 576         unsigned no_removexattr:1;
 577
 578         /** Are posix file locking primitives not implemented by fs? */
 579         unsigned no_lock:1;
 580
 581         /** Is access not implemented by fs? */
 582         unsigned no_access:1;
 583
 584         /** Is create not implemented by fs? */
 585         unsigned no_create:1;
 586
 587         /** Is interrupt not implemented by fs? */
 588         unsigned no_interrupt:1;
 589
 590         /** Is bmap not implemented by fs? */
 591         unsigned no_bmap:1;
 592
 593         /** Is poll not implemented by fs? */
 594         unsigned no_poll:1;
 595
 596         /** Do multi-page cached writes */
 597         unsigned big_writes:1;
 598
 599         /** Don't apply umask to creation modes */
 600         unsigned dont_mask:1;
 601
 602         /** Are BSD file locking primitives not implemented by fs? */
 603         unsigned no_flock:1;
 604
 605         /** Is fallocate not implemented by fs? */
 606         unsigned no_fallocate:1;
 607
 608         /** Is rename with flags implemented by fs? */
 609         unsigned no_rename2:1;
 610
 611         /** Use enhanced/automatic page cache invalidation. */
 612         unsigned auto_inval_data:1;
 613
 614         /** Does the filesystem support readdirplus? */
 615         unsigned do_readdirplus:1;
 616
 617         /** Does the filesystem want adaptive readdirplus? */
 618         unsigned readdirplus_auto:1;
 619
 620         /** Does the filesystem support asynchronous direct-IO submission? */
 621         unsigned async_dio:1;
 622
 623         /** Is lseek not implemented by fs? */
 624         unsigned no_lseek:1;
 625
 626         /** The number of requests waiting for completion */
 627         atomic_t num_waiting;
 628
 629         /** Negotiated minor version */
 630         unsigned minor;
 631
 632         /** Backing dev info */
 633         struct backing_dev_info bdi;
 634
 635         /** Entry on the fuse_conn_list */
 636         struct list_head entry;
 637
 638         /** Device ID from super block */
 639         dev_t dev;
 640
 641         /** Dentries in the control filesystem */
 642         struct dentry *ctl_dentry[FUSE_CTL_NUM_DENTRIES];
 643
 644         /** number of dentries used in the above array */
 645         int ctl_ndents;
 646
 647         /** Key for lock owner ID scrambling */
 648         u32 scramble_key[4];
 649
 650         /** Reserved request for the DESTROY message */
 651         struct fuse_req *destroy_req;
 652
 653         /** Version counter for attribute changes */
 654         u64 attr_version;
 655
 656         /** Called on final put */
 657         void (*release)(struct fuse_conn *);
 658
 659         /** Super block for this connection. */
 660         struct super_block *sb;
 661
 662         /** Read/write semaphore to hold when accessing sb. */
 663         struct rw_semaphore killsb;
 664
 665         /** List of device instances belonging to this connection */
 666         struct list_head devices;
 667 };
 668
 669 static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb)
 670 {
 671         return sb->s_fs_info;
 672 }
 673
 674 static inline struct fuse_conn *get_fuse_conn(struct inode *inode)
 675 {
 676         return get_fuse_conn_super(inode->i_sb);
 677 }
 678
 679 static inline struct fuse_inode *get_fuse_inode(struct inode *inode)
 680 {
 681         return container_of(inode, struct fuse_inode, inode);
 682 }
 683
 684 static inline u64 get_node_id(struct inode *inode)
 685 {
 686         return get_fuse_inode(inode)->nodeid;
 687 }
 688
 689 /** Device operations */
 690 extern const struct file_operations fuse_dev_operations;
 691
 692 extern const struct dentry_operations fuse_dentry_operations;
 693
 694 /**
 695  * Inode to nodeid comparison.
 696  */
 697 int fuse_inode_eq(struct inode *inode, void *_nodeidp);
 698
 699 /**
 700  * Get a filled in inode
 701  */
 702 struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
 703                         int generation, struct fuse_attr *attr,
 704                         u64 attr_valid, u64 attr_version);
 705
 706 int fuse_lookup_name(struct super_block *sb, u64 nodeid, struct qstr *name,
 707                      struct fuse_entry_out *outarg, struct inode **inode);
 708
 709 /**
 710  * Send FORGET command
 711  */
 712 void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget,
 713                        u64 nodeid, u64 nlookup);
 714
 715 struct fuse_forget_link *fuse_alloc_forget(void);
 716
 717 /* Used by READDIRPLUS */
 718 void fuse_force_forget(struct file *file, u64 nodeid);
 719
 720 /**
 721  * Initialize READ or READDIR request
 722  */
 723 void fuse_read_fill(struct fuse_req *req, struct file *file,
 724                     loff_t pos, size_t count, int opcode);
 725
 726 /**
 727  * Send OPEN or OPENDIR request
 728  */
 729 int fuse_open_common(struct inode *inode, struct file *file, bool isdir);
 730
 731 struct fuse_file *fuse_file_alloc(struct fuse_conn *fc);
 732 struct fuse_file *fuse_file_get(struct fuse_file *ff);
 733 void fuse_file_free(struct fuse_file *ff);
 734 void fuse_finish_open(struct inode *inode, struct file *file);
 735
 736 void fuse_sync_release(struct fuse_file *ff, int flags);
 737
 738 /**
 739  * Send RELEASE or RELEASEDIR request
 740  */
 741 void fuse_release_common(struct file *file, int opcode);
 742
 743 /**
 744  * Send FSYNC or FSYNCDIR request
 745  */
 746 int fuse_fsync_common(struct file *file, loff_t start, loff_t end,
 747                       int datasync, int isdir);
 748
 749 /**
 750  * Notify poll wakeup
 751  */
 752 int fuse_notify_poll_wakeup(struct fuse_conn *fc,
 753                             struct fuse_notify_poll_wakeup_out *outarg);
 754
 755 /**
 756  * Initialize file operations on a regular file
 757  */
 758 void fuse_init_file_inode(struct inode *inode);
 759
 760 /**
 761  * Initialize inode operations on regular files and special files
 762  */
 763 void fuse_init_common(struct inode *inode);
 764
 765 /**
 766  * Initialize inode and file operations on a directory
 767  */
 768 void fuse_init_dir(struct inode *inode);
 769
 770 /**
 771  * Initialize inode operations on a symlink
 772  */
 773 void fuse_init_symlink(struct inode *inode);
 774
 775 /**
 776  * Change attributes of an inode
 777  */
 778 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
 779                             u64 attr_valid, u64 attr_version);
 780
 781 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
 782                                    u64 attr_valid);
 783
 784 /**
 785  * Initialize the client device
 786  */
 787 int fuse_dev_init(void);
 788
 789 /**
 790  * Cleanup the client device
 791  */
 792 void fuse_dev_cleanup(void);
 793
 794 int fuse_ctl_init(void);
 795 void __exit fuse_ctl_cleanup(void);
 796
 797 /**
 798  * Allocate a request
 799  */
 800 struct fuse_req *fuse_request_alloc(unsigned npages);
 801
 802 struct fuse_req *fuse_request_alloc_nofs(unsigned npages);
 803
 804 /**
 805  * Free a request
 806  */
 807 void fuse_request_free(struct fuse_req *req);
 808
 809 /**
 810  * Get a request, may fail with -ENOMEM,
 811  * caller should specify # elements in req->pages[] explicitly
 812  */
 813 struct fuse_req *fuse_get_req(struct fuse_conn *fc, unsigned npages);
 814 struct fuse_req *fuse_get_req_for_background(struct fuse_conn *fc,
 815                                              unsigned npages);
 816
 817 /*
 818  * Increment reference count on request
 819  */
 820 void __fuse_get_request(struct fuse_req *req);
 821
 822 /**
 823  * Gets a requests for a file operation, always succeeds
 824  */
 825 struct fuse_req *fuse_get_req_nofail_nopages(struct fuse_conn *fc,
 826                                              struct file *file);
 827
 828 /**
 829  * Decrement reference count of a request.  If count goes to zero free
 830  * the request.
 831  */
 832 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req);
 833
 834 /**
 835  * Send a request (synchronous)
 836  */
 837 void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req);
 838
 839 /**
 840  * Simple request sending that does request allocation and freeing
 841  */
 842 ssize_t fuse_simple_request(struct fuse_conn *fc, struct fuse_args *args);
 843
 844 /**
 845  * Send a request in the background
 846  */
 847 void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req);
 848
 849 void fuse_request_send_background_locked(struct fuse_conn *fc,
 850                                          struct fuse_req *req);
 851
 852 /* Abort all requests */
 853 void fuse_abort_conn(struct fuse_conn *fc);
 854
 855 /**
 856  * Invalidate inode attributes
 857  */
 858 void fuse_invalidate_attr(struct inode *inode);
 859
 860 void fuse_invalidate_entry_cache(struct dentry *entry);
 861
 862 void fuse_invalidate_atime(struct inode *inode);
 863
 864 /**
 865  * Acquire reference to fuse_conn
 866  */
 867 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc);
 868
 869 /**
 870  * Initialize fuse_conn
 871  */
 872 void fuse_conn_init(struct fuse_conn *fc);
 873
 874 /**
 875  * Release reference to fuse_conn
 876  */
 877 void fuse_conn_put(struct fuse_conn *fc);
 878
 879 struct fuse_dev *fuse_dev_alloc(struct fuse_conn *fc);
 880 void fuse_dev_free(struct fuse_dev *fud);
 881
 882 /**
 883  * Add connection to control filesystem
 884  */
 885 int fuse_ctl_add_conn(struct fuse_conn *fc);
 886
 887 /**
 888  * Remove connection from control filesystem
 889  */
 890 void fuse_ctl_remove_conn(struct fuse_conn *fc);
 891
 892 /**
 893  * Is file type valid?
 894  */
 895 int fuse_valid_type(int m);
 896
 897 /**
 898  * Is current process allowed to perform filesystem operation?
 899  */
 900 int fuse_allow_current_process(struct fuse_conn *fc);
 901
 902 u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id);
 903
 904 int fuse_update_attributes(struct inode *inode, struct kstat *stat,
 905                            struct file *file, bool *refreshed);
 906
 907 void fuse_flush_writepages(struct inode *inode);
 908
 909 void fuse_set_nowrite(struct inode *inode);
 910 void fuse_release_nowrite(struct inode *inode);
 911
 912 u64 fuse_get_attr_version(struct fuse_conn *fc);
 913
 914 /**
 915  * File-system tells the kernel to invalidate cache for the given node id.
 916  */
 917 int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid,
 918                              loff_t offset, loff_t len);
 919
 920 /**
 921  * File-system tells the kernel to invalidate parent attributes and
 922  * the dentry matching parent/name.
 923  *
 924  * If the child_nodeid is non-zero and:
 925  *    - matches the inode number for the dentry matching parent/name,
 926  *    - is not a mount point
 927  *    - is a file or oan empty directory
 928  * then the dentry is unhashed (d_delete()).
 929  */
 930 int fuse_reverse_inval_entry(struct super_block *sb, u64 parent_nodeid,
 931                              u64 child_nodeid, struct qstr *name);
 932
 933 int fuse_do_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
 934                  bool isdir);
 935
 936 /**
 937  * fuse_direct_io() flags
 938  */
 939
 940 /** If set, it is WRITE; otherwise - READ */
 941 #define FUSE_DIO_WRITE (1 << 0)
 942
 943 /** CUSE pass fuse_direct_io() a file which f_mapping->host is not from FUSE */
 944 #define FUSE_DIO_CUSE  (1 << 1)
 945
 946 ssize_t fuse_direct_io(struct fuse_io_priv *io, struct iov_iter *iter,
 947                        loff_t *ppos, int flags);
 948 long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
 949                    unsigned int flags);
 950 long fuse_ioctl_common(struct file *file, unsigned int cmd,
 951                        unsigned long arg, unsigned int flags);
 952 unsigned fuse_file_poll(struct file *file, poll_table *wait);
 953 int fuse_dev_release(struct inode *inode, struct file *file);
 954
 955 bool fuse_write_update_size(struct inode *inode, loff_t pos);
 956
 957 int fuse_flush_times(struct inode *inode, struct fuse_file *ff);
 958 int fuse_write_inode(struct inode *inode, struct writeback_control *wbc);
 959
 960 int fuse_do_setattr(struct inode *inode, struct iattr *attr,
 961                     struct file *file);
 962
 963 void fuse_set_initialized(struct fuse_conn *fc);
 964
 965 void fuse_unlock_inode(struct inode *inode);
 966 void fuse_lock_inode(struct inode *inode);
 967
 968 #endif /* _FS_FUSE_I_H */