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 #include <linux/xattr.h>
  27 #include <linux/pid_namespace.h>
  28 #include <linux/refcount.h>
  29 #include <linux/user_namespace.h>
  30
  31 /** Max number of pages that can be used in a single read request */
  32 #define FUSE_MAX_PAGES_PER_REQ 32
  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 5
  42
  43 /** Number of page pointers embedded in fuse_req */
  44 #define FUSE_REQ_INLINE_PAGES 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         umode_t orig_i_mode;
  83
  84         /** 64 bit inode number */
  85         u64 orig_ino;
  86
  87         /** Version of last attribute change */
  88         u64 attr_version;
  89
  90         /** Files usable in writepage.  Protected by fc->lock */
  91         struct list_head write_files;
  92
  93         /** Writepages pending on truncate or fsync */
  94         struct list_head queued_writes;
  95
  96         /** Number of sent writes, a negative bias (FUSE_NOWRITE)
  97          * means more writes are blocked */
  98         int writectr;
  99
 100         /** Waitq for writepage completion */
 101         wait_queue_head_t page_waitq;
 102
 103         /** List of writepage requestst (pending or sent) */
 104         struct list_head writepages;
 105
 106         /** Miscellaneous bits describing inode state */
 107         unsigned long state;
 108
 109         /** Lock for serializing lookup and readdir for back compatibility*/
 110         struct mutex mutex;
 111 };
 112
 113 /** FUSE inode state bits */
 114 enum {
 115         /** Advise readdirplus  */
 116         FUSE_I_ADVISE_RDPLUS,
 117         /** Initialized with readdirplus */
 118         FUSE_I_INIT_RDPLUS,
 119         /** An operation changing file size is in progress  */
 120         FUSE_I_SIZE_UNSTABLE,
 121 };
 122
 123 struct fuse_conn;
 124
 125 /** FUSE specific file data */
 126 struct fuse_file {
 127         /** Fuse connection for this file */
 128         struct fuse_conn *fc;
 129
 130         /** Request reserved for flush and release */
 131         struct fuse_req *reserved_req;
 132
 133         /** Kernel file handle guaranteed to be unique */
 134         u64 kh;
 135
 136         /** File handle used by userspace */
 137         u64 fh;
 138
 139         /** Node id of this file */
 140         u64 nodeid;
 141
 142         /** Refcount */
 143         refcount_t count;
 144
 145         /** FOPEN_* flags returned by open */
 146         u32 open_flags;
 147
 148         /** Entry on inode's write_files list */
 149         struct list_head write_entry;
 150
 151         /** RB node to be linked on fuse_conn->polled_files */
 152         struct rb_node polled_node;
 153
 154         /** Wait queue head for poll */
 155         wait_queue_head_t poll_wait;
 156
 157         /** Has flock been performed on this file? */
 158         bool flock:1;
 159 };
 160
 161 /** One input argument of a request */
 162 struct fuse_in_arg {
 163         unsigned size;
 164         const void *value;
 165 };
 166
 167 /** The request input */
 168 struct fuse_in {
 169         /** The request header */
 170         struct fuse_in_header h;
 171
 172         /** True if the data for the last argument is in req->pages */
 173         unsigned argpages:1;
 174
 175         /** Number of arguments */
 176         unsigned numargs;
 177
 178         /** Array of arguments */
 179         struct fuse_in_arg args[3];
 180 };
 181
 182 /** One output argument of a request */
 183 struct fuse_arg {
 184         unsigned size;
 185         void *value;
 186 };
 187
 188 /** The request output */
 189 struct fuse_out {
 190         /** Header returned from userspace */
 191         struct fuse_out_header h;
 192
 193         /*
 194          * The following bitfields are not changed during the request
 195          * processing
 196          */
 197
 198         /** Last argument is variable length (can be shorter than
 199             arg->size) */
 200         unsigned argvar:1;
 201
 202         /** Last argument is a list of pages to copy data to */
 203         unsigned argpages:1;
 204
 205         /** Zero partially or not copied pages */
 206         unsigned page_zeroing:1;
 207
 208         /** Pages may be replaced with new ones */
 209         unsigned page_replace:1;
 210
 211         /** Number or arguments */
 212         unsigned numargs;
 213
 214         /** Array of arguments */
 215         struct fuse_arg args[2];
 216 };
 217
 218 /** FUSE page descriptor */
 219 struct fuse_page_desc {
 220         unsigned int length;
 221         unsigned int offset;
 222 };
 223
 224 struct fuse_args {
 225         struct {
 226                 struct {
 227                         uint32_t opcode;
 228                         uint64_t nodeid;
 229                 } h;
 230                 unsigned numargs;
 231                 struct fuse_in_arg args[3];
 232
 233         } in;
 234         struct {
 235                 unsigned argvar:1;
 236                 unsigned numargs;
 237                 struct fuse_arg args[2];
 238         } out;
 239 };
 240
 241 #define FUSE_ARGS(args) struct fuse_args args = {}
 242
 243 /** The request IO state (for asynchronous processing) */
 244 struct fuse_io_priv {
 245         struct kref refcnt;
 246         int async;
 247         spinlock_t lock;
 248         unsigned reqs;
 249         ssize_t bytes;
 250         size_t size;
 251         __u64 offset;
 252         bool write;
 253         bool should_dirty;
 254         int err;
 255         struct kiocb *iocb;
 256         struct file *file;
 257         struct completion *done;
 258         bool blocking;
 259 };
 260
 261 #define FUSE_IO_PRIV_SYNC(f) \
 262 {                                       \
 263         .refcnt = KREF_INIT(1),         \
 264         .async = 0,                     \
 265         .file = f,                      \
 266 }
 267
 268 /**
 269  * Request flags
 270  *
 271  * FR_ISREPLY:          set if the request has reply
 272  * FR_FORCE:            force sending of the request even if interrupted
 273  * FR_BACKGROUND:       request is sent in the background
 274  * FR_WAITING:          request is counted as "waiting"
 275  * FR_ABORTED:          the request was aborted
 276  * FR_INTERRUPTED:      the request has been interrupted
 277  * FR_LOCKED:           data is being copied to/from the request
 278  * FR_PENDING:          request is not yet in userspace
 279  * FR_SENT:             request is in userspace, waiting for an answer
 280  * FR_FINISHED:         request is finished
 281  * FR_PRIVATE:          request is on private list
 282  */
 283 enum fuse_req_flag {
 284         FR_ISREPLY,
 285         FR_FORCE,
 286         FR_BACKGROUND,
 287         FR_WAITING,
 288         FR_ABORTED,
 289         FR_INTERRUPTED,
 290         FR_LOCKED,
 291         FR_PENDING,
 292         FR_SENT,
 293         FR_FINISHED,
 294         FR_PRIVATE,
 295 };
 296
 297 /**
 298  * A request to the client
 299  *
 300  * .waitq.lock protects the following fields:
 301  *   - FR_ABORTED
 302  *   - FR_LOCKED (may also be modified under fc->lock, tested under both)
 303  */
 304 struct fuse_req {
 305         /** This can be on either pending processing or io lists in
 306             fuse_conn */
 307         struct list_head list;
 308
 309         /** Entry on the interrupts list  */
 310         struct list_head intr_entry;
 311
 312         /** refcount */
 313         refcount_t count;
 314
 315         /** Unique ID for the interrupt request */
 316         u64 intr_unique;
 317
 318         /* Request flags, updated with test/set/clear_bit() */
 319         unsigned long flags;
 320
 321         /** The request input */
 322         struct fuse_in in;
 323
 324         /** The request output */
 325         struct fuse_out out;
 326
 327         /** Used to wake up the task waiting for completion of request*/
 328         wait_queue_head_t waitq;
 329
 330         /** Data for asynchronous requests */
 331         union {
 332                 struct {
 333                         struct fuse_release_in in;
 334                         struct inode *inode;
 335                 } release;
 336                 struct fuse_init_in init_in;
 337                 struct fuse_init_out init_out;
 338                 struct cuse_init_in cuse_init_in;
 339                 struct {
 340                         struct fuse_read_in in;
 341                         u64 attr_ver;
 342                 } read;
 343                 struct {
 344                         struct fuse_write_in in;
 345                         struct fuse_write_out out;
 346                         struct fuse_req *next;
 347                 } write;
 348                 struct fuse_notify_retrieve_in retrieve_in;
 349         } misc;
 350
 351         /** page vector */
 352         struct page **pages;
 353
 354         /** page-descriptor vector */
 355         struct fuse_page_desc *page_descs;
 356
 357         /** size of the 'pages' array */
 358         unsigned max_pages;
 359
 360         /** inline page vector */
 361         struct page *inline_pages[FUSE_REQ_INLINE_PAGES];
 362
 363         /** inline page-descriptor vector */
 364         struct fuse_page_desc inline_page_descs[FUSE_REQ_INLINE_PAGES];
 365
 366         /** number of pages in vector */
 367         unsigned num_pages;
 368
 369         /** File used in the request (or NULL) */
 370         struct fuse_file *ff;
 371
 372         /** Inode used in the request or NULL */
 373         struct inode *inode;
 374
 375         /** AIO control block */
 376         struct fuse_io_priv *io;
 377
 378         /** Link on fi->writepages */
 379         struct list_head writepages_entry;
 380
 381         /** Request completion callback */
 382         void (*end)(struct fuse_conn *, struct fuse_req *);
 383
 384         /** Request is stolen from fuse_file->reserved_req */
 385         struct file *stolen_file;
 386 };
 387
 388 struct fuse_iqueue {
 389         /** Connection established */
 390         unsigned connected;
 391
 392         /** Readers of the connection are waiting on this */
 393         wait_queue_head_t waitq;
 394
 395         /** The next unique request id */
 396         u64 reqctr;
 397
 398         /** The list of pending requests */
 399         struct list_head pending;
 400
 401         /** Pending interrupts */
 402         struct list_head interrupts;
 403
 404         /** Queue of pending forgets */
 405         struct fuse_forget_link forget_list_head;
 406         struct fuse_forget_link *forget_list_tail;
 407
 408         /** Batching of FORGET requests (positive indicates FORGET batch) */
 409         int forget_batch;
 410
 411         /** O_ASYNC requests */
 412         struct fasync_struct *fasync;
 413 };
 414
 415 struct fuse_pqueue {
 416         /** Connection established */
 417         unsigned connected;
 418
 419         /** Lock protecting accessess to  members of this structure */
 420         spinlock_t lock;
 421
 422         /** The list of requests being processed */
 423         struct list_head processing;
 424
 425         /** The list of requests under I/O */
 426         struct list_head io;
 427 };
 428
 429 /**
 430  * Fuse device instance
 431  */
 432 struct fuse_dev {
 433         /** Fuse connection for this device */
 434         struct fuse_conn *fc;
 435
 436         /** Processing queue */
 437         struct fuse_pqueue pq;
 438
 439         /** list entry on fc->devices */
 440         struct list_head entry;
 441 };
 442
 443 /**
 444  * A Fuse connection.
 445  *
 446  * This structure is created, when the filesystem is mounted, and is
 447  * destroyed, when the client device is closed and the filesystem is
 448  * unmounted.
 449  */
 450 struct fuse_conn {
 451         /** Lock protecting accessess to  members of this structure */
 452         spinlock_t lock;
 453
 454         /** Refcount */
 455         refcount_t count;
 456
 457         /** Number of fuse_dev's */
 458         atomic_t dev_count;
 459
 460         struct rcu_head rcu;
 461
 462         /** The user id for this mount */
 463         kuid_t user_id;
 464
 465         /** The group id for this mount */
 466         kgid_t group_id;
 467
 468         /** The pid namespace for this mount */
 469         struct pid_namespace *pid_ns;
 470
 471         /** The user namespace for this mount */
 472         struct user_namespace *user_ns;
 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         /** write-back cache policy (default is write-through) */
 541         unsigned writeback_cache:1;
 542
 543         /** allow parallel lookups and readdir (default is serialized) */
 544         unsigned parallel_dirops:1;
 545
 546         /** handle fs handles killing suid/sgid/cap on write/chown/trunc */
 547         unsigned handle_killpriv: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         /** Does the filesystem support posix acls? */
 627         unsigned posix_acl:1;
 628
 629         /** Check permissions based on the file mode or not? */
 630         unsigned default_permissions:1;
 631
 632         /** Allow other than the mounter user to access the filesystem ? */
 633         unsigned allow_other:1;
 634
 635         /** The number of requests waiting for completion */
 636         atomic_t num_waiting;
 637
 638         /** Negotiated minor version */
 639         unsigned minor;
 640
 641         /** Entry on the fuse_conn_list */
 642         struct list_head entry;
 643
 644         /** Device ID from super block */
 645         dev_t dev;
 646
 647         /** Dentries in the control filesystem */
 648         struct dentry *ctl_dentry[FUSE_CTL_NUM_DENTRIES];
 649
 650         /** number of dentries used in the above array */
 651         int ctl_ndents;
 652
 653         /** Key for lock owner ID scrambling */
 654         u32 scramble_key[4];
 655
 656         /** Reserved request for the DESTROY message */
 657         struct fuse_req *destroy_req;
 658
 659         /** Version counter for attribute changes */
 660         u64 attr_version;
 661
 662         /** Called on final put */
 663         void (*release)(struct fuse_conn *);
 664
 665         /** Super block for this connection. */
 666         struct super_block *sb;
 667
 668         /** Read/write semaphore to hold when accessing sb. */
 669         struct rw_semaphore killsb;
 670
 671         /** List of device instances belonging to this connection */
 672         struct list_head devices;
 673 };
 674
 675 static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb)
 676 {
 677         return sb->s_fs_info;
 678 }
 679
 680 static inline struct fuse_conn *get_fuse_conn(struct inode *inode)
 681 {
 682         return get_fuse_conn_super(inode->i_sb);
 683 }
 684
 685 static inline struct fuse_inode *get_fuse_inode(struct inode *inode)
 686 {
 687         return container_of(inode, struct fuse_inode, inode);
 688 }
 689
 690 static inline u64 get_node_id(struct inode *inode)
 691 {
 692         return get_fuse_inode(inode)->nodeid;
 693 }
 694
 695 /** Device operations */
 696 extern const struct file_operations fuse_dev_operations;
 697
 698 extern const struct dentry_operations fuse_dentry_operations;
 699 extern const struct dentry_operations fuse_root_dentry_operations;
 700
 701 /**
 702  * Inode to nodeid comparison.
 703  */
 704 int fuse_inode_eq(struct inode *inode, void *_nodeidp);
 705
 706 /**
 707  * Get a filled in inode
 708  */
 709 struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
 710                         int generation, struct fuse_attr *attr,
 711                         u64 attr_valid, u64 attr_version);
 712
 713 int fuse_lookup_name(struct super_block *sb, u64 nodeid, const struct qstr *name,
 714                      struct fuse_entry_out *outarg, struct inode **inode);
 715
 716 /**
 717  * Send FORGET command
 718  */
 719 void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget,
 720                        u64 nodeid, u64 nlookup);
 721
 722 struct fuse_forget_link *fuse_alloc_forget(void);
 723
 724 /* Used by READDIRPLUS */
 725 void fuse_force_forget(struct file *file, u64 nodeid);
 726
 727 /**
 728  * Initialize READ or READDIR request
 729  */
 730 void fuse_read_fill(struct fuse_req *req, struct file *file,
 731                     loff_t pos, size_t count, int opcode);
 732
 733 /**
 734  * Send OPEN or OPENDIR request
 735  */
 736 int fuse_open_common(struct inode *inode, struct file *file, bool isdir);
 737
 738 struct fuse_file *fuse_file_alloc(struct fuse_conn *fc);
 739 void fuse_file_free(struct fuse_file *ff);
 740 void fuse_finish_open(struct inode *inode, struct file *file);
 741
 742 void fuse_sync_release(struct fuse_file *ff, int flags);
 743
 744 /**
 745  * Send RELEASE or RELEASEDIR request
 746  */
 747 void fuse_release_common(struct file *file, int opcode);
 748
 749 /**
 750  * Send FSYNC or FSYNCDIR request
 751  */
 752 int fuse_fsync_common(struct file *file, loff_t start, loff_t end,
 753                       int datasync, int isdir);
 754
 755 /**
 756  * Notify poll wakeup
 757  */
 758 int fuse_notify_poll_wakeup(struct fuse_conn *fc,
 759                             struct fuse_notify_poll_wakeup_out *outarg);
 760
 761 /**
 762  * Initialize file operations on a regular file
 763  */
 764 void fuse_init_file_inode(struct inode *inode);
 765
 766 /**
 767  * Initialize inode operations on regular files and special files
 768  */
 769 void fuse_init_common(struct inode *inode);
 770
 771 /**
 772  * Initialize inode and file operations on a directory
 773  */
 774 void fuse_init_dir(struct inode *inode);
 775
 776 /**
 777  * Initialize inode operations on a symlink
 778  */
 779 void fuse_init_symlink(struct inode *inode);
 780
 781 /**
 782  * Change attributes of an inode
 783  */
 784 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
 785                             u64 attr_valid, u64 attr_version);
 786
 787 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
 788                                    u64 attr_valid);
 789
 790 /**
 791  * Initialize the client device
 792  */
 793 int fuse_dev_init(void);
 794
 795 /**
 796  * Cleanup the client device
 797  */
 798 void fuse_dev_cleanup(void);
 799
 800 int fuse_ctl_init(void);
 801 void __exit fuse_ctl_cleanup(void);
 802
 803 /**
 804  * Allocate a request
 805  */
 806 struct fuse_req *fuse_request_alloc(unsigned npages);
 807
 808 struct fuse_req *fuse_request_alloc_nofs(unsigned npages);
 809
 810 /**
 811  * Free a request
 812  */
 813 void fuse_request_free(struct fuse_req *req);
 814
 815 /**
 816  * Get a request, may fail with -ENOMEM,
 817  * caller should specify # elements in req->pages[] explicitly
 818  */
 819 struct fuse_req *fuse_get_req(struct fuse_conn *fc, unsigned npages);
 820 struct fuse_req *fuse_get_req_for_background(struct fuse_conn *fc,
 821                                              unsigned npages);
 822
 823 /*
 824  * Increment reference count on request
 825  */
 826 void __fuse_get_request(struct fuse_req *req);
 827
 828 /**
 829  * Gets a requests for a file operation, always succeeds
 830  */
 831 struct fuse_req *fuse_get_req_nofail_nopages(struct fuse_conn *fc,
 832                                              struct file *file);
 833
 834 /**
 835  * Decrement reference count of a request.  If count goes to zero free
 836  * the request.
 837  */
 838 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req);
 839
 840 /**
 841  * Send a request (synchronous)
 842  */
 843 void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req);
 844
 845 /**
 846  * Simple request sending that does request allocation and freeing
 847  */
 848 ssize_t fuse_simple_request(struct fuse_conn *fc, struct fuse_args *args);
 849
 850 /**
 851  * Send a request in the background
 852  */
 853 void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req);
 854
 855 void fuse_request_send_background_locked(struct fuse_conn *fc,
 856                                          struct fuse_req *req);
 857
 858 /* Abort all requests */
 859 void fuse_abort_conn(struct fuse_conn *fc);
 860
 861 /**
 862  * Invalidate inode attributes
 863  */
 864 void fuse_invalidate_attr(struct inode *inode);
 865
 866 void fuse_invalidate_entry_cache(struct dentry *entry);
 867
 868 void fuse_invalidate_atime(struct inode *inode);
 869
 870 /**
 871  * Acquire reference to fuse_conn
 872  */
 873 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc);
 874
 875 /**
 876  * Initialize fuse_conn
 877  */
 878 void fuse_conn_init(struct fuse_conn *fc, struct user_namespace *user_ns);
 879
 880 /**
 881  * Release reference to fuse_conn
 882  */
 883 void fuse_conn_put(struct fuse_conn *fc);
 884
 885 struct fuse_dev *fuse_dev_alloc(struct fuse_conn *fc);
 886 void fuse_dev_free(struct fuse_dev *fud);
 887
 888 /**
 889  * Add connection to control filesystem
 890  */
 891 int fuse_ctl_add_conn(struct fuse_conn *fc);
 892
 893 /**
 894  * Remove connection from control filesystem
 895  */
 896 void fuse_ctl_remove_conn(struct fuse_conn *fc);
 897
 898 /**
 899  * Is file type valid?
 900  */
 901 int fuse_valid_type(int m);
 902
 903 /**
 904  * Is current process allowed to perform filesystem operation?
 905  */
 906 int fuse_allow_current_process(struct fuse_conn *fc);
 907
 908 u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id);
 909
 910 void fuse_update_ctime(struct inode *inode);
 911
 912 int fuse_update_attributes(struct inode *inode, struct kstat *stat,
 913                            struct file *file, bool *refreshed);
 914
 915 void fuse_flush_writepages(struct inode *inode);
 916
 917 void fuse_set_nowrite(struct inode *inode);
 918 void fuse_release_nowrite(struct inode *inode);
 919
 920 u64 fuse_get_attr_version(struct fuse_conn *fc);
 921
 922 /**
 923  * File-system tells the kernel to invalidate cache for the given node id.
 924  */
 925 int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid,
 926                              loff_t offset, loff_t len);
 927
 928 /**
 929  * File-system tells the kernel to invalidate parent attributes and
 930  * the dentry matching parent/name.
 931  *
 932  * If the child_nodeid is non-zero and:
 933  *    - matches the inode number for the dentry matching parent/name,
 934  *    - is not a mount point
 935  *    - is a file or oan empty directory
 936  * then the dentry is unhashed (d_delete()).
 937  */
 938 int fuse_reverse_inval_entry(struct super_block *sb, u64 parent_nodeid,
 939                              u64 child_nodeid, struct qstr *name);
 940
 941 int fuse_do_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
 942                  bool isdir);
 943
 944 /**
 945  * fuse_direct_io() flags
 946  */
 947
 948 /** If set, it is WRITE; otherwise - READ */
 949 #define FUSE_DIO_WRITE (1 << 0)
 950
 951 /** CUSE pass fuse_direct_io() a file which f_mapping->host is not from FUSE */
 952 #define FUSE_DIO_CUSE  (1 << 1)
 953
 954 ssize_t fuse_direct_io(struct fuse_io_priv *io, struct iov_iter *iter,
 955                        loff_t *ppos, int flags);
 956 long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
 957                    unsigned int flags);
 958 long fuse_ioctl_common(struct file *file, unsigned int cmd,
 959                        unsigned long arg, unsigned int flags);
 960 unsigned fuse_file_poll(struct file *file, poll_table *wait);
 961 int fuse_dev_release(struct inode *inode, struct file *file);
 962
 963 bool fuse_write_update_size(struct inode *inode, loff_t pos);
 964
 965 int fuse_flush_times(struct inode *inode, struct fuse_file *ff);
 966 int fuse_write_inode(struct inode *inode, struct writeback_control *wbc);
 967
 968 int fuse_do_setattr(struct dentry *dentry, struct iattr *attr,
 969                     struct file *file);
 970
 971 void fuse_set_initialized(struct fuse_conn *fc);
 972
 973 void fuse_unlock_inode(struct inode *inode);
 974 void fuse_lock_inode(struct inode *inode);
 975
 976 int fuse_setxattr(struct inode *inode, const char *name, const void *value,
 977                   size_t size, int flags);
 978 ssize_t fuse_getxattr(struct inode *inode, const char *name, void *value,
 979                       size_t size);
 980 ssize_t fuse_listxattr(struct dentry *entry, char *list, size_t size);
 981 int fuse_removexattr(struct inode *inode, const char *name);
 982 extern const struct xattr_handler *fuse_xattr_handlers[];
 983 extern const struct xattr_handler *fuse_acl_xattr_handlers[];
 984
 985 struct posix_acl;
 986 struct posix_acl *fuse_get_acl(struct inode *inode, int type);
 987 int fuse_set_acl(struct inode *inode, struct posix_acl *acl, int type);
 988
 989 #endif /* _FS_FUSE_I_H */