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 #ifndef pr_fmt
  13 # define pr_fmt(fmt) "fuse: " fmt
  14 #endif
  15
  16 #include <linux/fuse.h>
  17 #include <linux/fs.h>
  18 #include <linux/mount.h>
  19 #include <linux/wait.h>
  20 #include <linux/list.h>
  21 #include <linux/spinlock.h>
  22 #include <linux/mm.h>
  23 #include <linux/backing-dev.h>
  24 #include <linux/mutex.h>
  25 #include <linux/rwsem.h>
  26 #include <linux/rbtree.h>
  27 #include <linux/poll.h>
  28 #include <linux/workqueue.h>
  29 #include <linux/kref.h>
  30 #include <linux/xattr.h>
  31 #include <linux/pid_namespace.h>
  32 #include <linux/refcount.h>
  33 #include <linux/user_namespace.h>
  34
  35 /** Default max number of pages that can be used in a single read request */
  36 #define FUSE_DEFAULT_MAX_PAGES_PER_REQ 32
  37
  38 /** Maximum of max_pages received in init_out */
  39 #define FUSE_MAX_MAX_PAGES 256
  40
  41 /** Bias for fi->writectr, meaning new writepages must not be sent */
  42 #define FUSE_NOWRITE INT_MIN
  43
  44 /** It could be as large as PATH_MAX, but would that have any uses? */
  45 #define FUSE_NAME_MAX 1024
  46
  47 /** Number of dentries for each connection in the control filesystem */
  48 #define FUSE_CTL_NUM_DENTRIES 5
  49
  50 /** Number of page pointers embedded in fuse_req */
  51 #define FUSE_REQ_INLINE_PAGES 1
  52
  53 /** List of active connections */
  54 extern struct list_head fuse_conn_list;
  55
  56 /** Global mutex protecting fuse_conn_list and the control filesystem */
  57 extern struct mutex fuse_mutex;
  58
  59 /** Module parameters */
  60 extern unsigned max_user_bgreq;
  61 extern unsigned max_user_congthresh;
  62
  63 /* One forget request */
  64 struct fuse_forget_link {
  65         struct fuse_forget_one forget_one;
  66         struct fuse_forget_link *next;
  67 };
  68
  69 /** FUSE inode */
  70 struct fuse_inode {
  71         /** Inode data */
  72         struct inode inode;
  73
  74         /** Unique ID, which identifies the inode between userspace
  75          * and kernel */
  76         u64 nodeid;
  77
  78         /** Number of lookups on this inode */
  79         u64 nlookup;
  80
  81         /** The request used for sending the FORGET message */
  82         struct fuse_forget_link *forget;
  83
  84         /** Time in jiffies until the file attributes are valid */
  85         u64 i_time;
  86
  87         /* Which attributes are invalid */
  88         u32 inval_mask;
  89
  90         /** The sticky bit in inode->i_mode may have been removed, so
  91             preserve the original mode */
  92         umode_t orig_i_mode;
  93
  94         /** 64 bit inode number */
  95         u64 orig_ino;
  96
  97         /** Version of last attribute change */
  98         u64 attr_version;
  99
 100         union {
 101                 /* Write related fields (regular file only) */
 102                 struct {
 103                         /* Files usable in writepage.  Protected by fi->lock */
 104                         struct list_head write_files;
 105
 106                         /* Writepages pending on truncate or fsync */
 107                         struct list_head queued_writes;
 108
 109                         /* Number of sent writes, a negative bias
 110                          * (FUSE_NOWRITE) means more writes are blocked */
 111                         int writectr;
 112
 113                         /* Waitq for writepage completion */
 114                         wait_queue_head_t page_waitq;
 115
 116                         /* List of writepage requestst (pending or sent) */
 117                         struct list_head writepages;
 118                 };
 119
 120                 /* readdir cache (directory only) */
 121                 struct {
 122                         /* true if fully cached */
 123                         bool cached;
 124
 125                         /* size of cache */
 126                         loff_t size;
 127
 128                         /* position at end of cache (position of next entry) */
 129                         loff_t pos;
 130
 131                         /* version of the cache */
 132                         u64 version;
 133
 134                         /* modification time of directory when cache was
 135                          * started */
 136                         struct timespec64 mtime;
 137
 138                         /* iversion of directory when cache was started */
 139                         u64 iversion;
 140
 141                         /* protects above fields */
 142                         spinlock_t lock;
 143                 } rdc;
 144         };
 145
 146         /** Miscellaneous bits describing inode state */
 147         unsigned long state;
 148
 149         /** Lock for serializing lookup and readdir for back compatibility*/
 150         struct mutex mutex;
 151
 152         /** Lock to protect write related fields */
 153         spinlock_t lock;
 154 };
 155
 156 /** FUSE inode state bits */
 157 enum {
 158         /** Advise readdirplus  */
 159         FUSE_I_ADVISE_RDPLUS,
 160         /** Initialized with readdirplus */
 161         FUSE_I_INIT_RDPLUS,
 162         /** An operation changing file size is in progress  */
 163         FUSE_I_SIZE_UNSTABLE,
 164 };
 165
 166 struct fuse_conn;
 167
 168 /** FUSE specific file data */
 169 struct fuse_file {
 170         /** Fuse connection for this file */
 171         struct fuse_conn *fc;
 172
 173         /*
 174          * Request reserved for flush and release.
 175          * Modified under relative fuse_inode::lock.
 176          */
 177         struct fuse_req *reserved_req;
 178
 179         /** Kernel file handle guaranteed to be unique */
 180         u64 kh;
 181
 182         /** File handle used by userspace */
 183         u64 fh;
 184
 185         /** Node id of this file */
 186         u64 nodeid;
 187
 188         /** Refcount */
 189         refcount_t count;
 190
 191         /** FOPEN_* flags returned by open */
 192         u32 open_flags;
 193
 194         /** Entry on inode's write_files list */
 195         struct list_head write_entry;
 196
 197         /* Readdir related */
 198         struct {
 199                 /*
 200                  * Protects below fields against (crazy) parallel readdir on
 201                  * same open file.  Uncontended in the normal case.
 202                  */
 203                 struct mutex lock;
 204
 205                 /* Dir stream position */
 206                 loff_t pos;
 207
 208                 /* Offset in cache */
 209                 loff_t cache_off;
 210
 211                 /* Version of cache we are reading */
 212                 u64 version;
 213
 214         } readdir;
 215
 216         /** RB node to be linked on fuse_conn->polled_files */
 217         struct rb_node polled_node;
 218
 219         /** Wait queue head for poll */
 220         wait_queue_head_t poll_wait;
 221
 222         /** Has flock been performed on this file? */
 223         bool flock:1;
 224 };
 225
 226 /** One input argument of a request */
 227 struct fuse_in_arg {
 228         unsigned size;
 229         const void *value;
 230 };
 231
 232 /** The request input */
 233 struct fuse_in {
 234         /** The request header */
 235         struct fuse_in_header h;
 236
 237         /** True if the data for the last argument is in req->pages */
 238         unsigned argpages:1;
 239
 240         /** Number of arguments */
 241         unsigned numargs;
 242
 243         /** Array of arguments */
 244         struct fuse_in_arg args[3];
 245 };
 246
 247 /** One output argument of a request */
 248 struct fuse_arg {
 249         unsigned size;
 250         void *value;
 251 };
 252
 253 /** The request output */
 254 struct fuse_out {
 255         /** Header returned from userspace */
 256         struct fuse_out_header h;
 257
 258         /*
 259          * The following bitfields are not changed during the request
 260          * processing
 261          */
 262
 263         /** Last argument is variable length (can be shorter than
 264             arg->size) */
 265         unsigned argvar:1;
 266
 267         /** Last argument is a list of pages to copy data to */
 268         unsigned argpages:1;
 269
 270         /** Zero partially or not copied pages */
 271         unsigned page_zeroing:1;
 272
 273         /** Pages may be replaced with new ones */
 274         unsigned page_replace:1;
 275
 276         /** Number or arguments */
 277         unsigned numargs;
 278
 279         /** Array of arguments */
 280         struct fuse_arg args[2];
 281 };
 282
 283 /** FUSE page descriptor */
 284 struct fuse_page_desc {
 285         unsigned int length;
 286         unsigned int offset;
 287 };
 288
 289 struct fuse_args {
 290         struct {
 291                 struct {
 292                         uint32_t opcode;
 293                         uint64_t nodeid;
 294                 } h;
 295                 unsigned numargs;
 296                 struct fuse_in_arg args[3];
 297
 298         } in;
 299         struct {
 300                 unsigned argvar:1;
 301                 unsigned numargs;
 302                 struct fuse_arg args[2];
 303         } out;
 304 };
 305
 306 #define FUSE_ARGS(args) struct fuse_args args = {}
 307
 308 /** The request IO state (for asynchronous processing) */
 309 struct fuse_io_priv {
 310         struct kref refcnt;
 311         int async;
 312         spinlock_t lock;
 313         unsigned reqs;
 314         ssize_t bytes;
 315         size_t size;
 316         __u64 offset;
 317         bool write;
 318         bool should_dirty;
 319         int err;
 320         struct kiocb *iocb;
 321         struct completion *done;
 322         bool blocking;
 323 };
 324
 325 #define FUSE_IO_PRIV_SYNC(i) \
 326 {                                       \
 327         .refcnt = KREF_INIT(1),         \
 328         .async = 0,                     \
 329         .iocb = i,                      \
 330 }
 331
 332 /**
 333  * Request flags
 334  *
 335  * FR_ISREPLY:          set if the request has reply
 336  * FR_FORCE:            force sending of the request even if interrupted
 337  * FR_BACKGROUND:       request is sent in the background
 338  * FR_WAITING:          request is counted as "waiting"
 339  * FR_ABORTED:          the request was aborted
 340  * FR_INTERRUPTED:      the request has been interrupted
 341  * FR_LOCKED:           data is being copied to/from the request
 342  * FR_PENDING:          request is not yet in userspace
 343  * FR_SENT:             request is in userspace, waiting for an answer
 344  * FR_FINISHED:         request is finished
 345  * FR_PRIVATE:          request is on private list
 346  */
 347 enum fuse_req_flag {
 348         FR_ISREPLY,
 349         FR_FORCE,
 350         FR_BACKGROUND,
 351         FR_WAITING,
 352         FR_ABORTED,
 353         FR_INTERRUPTED,
 354         FR_LOCKED,
 355         FR_PENDING,
 356         FR_SENT,
 357         FR_FINISHED,
 358         FR_PRIVATE,
 359 };
 360
 361 /**
 362  * A request to the client
 363  *
 364  * .waitq.lock protects the following fields:
 365  *   - FR_ABORTED
 366  *   - FR_LOCKED (may also be modified under fc->lock, tested under both)
 367  */
 368 struct fuse_req {
 369         /** This can be on either pending processing or io lists in
 370             fuse_conn */
 371         struct list_head list;
 372
 373         /** Entry on the interrupts list  */
 374         struct list_head intr_entry;
 375
 376         /** refcount */
 377         refcount_t count;
 378
 379         /* Request flags, updated with test/set/clear_bit() */
 380         unsigned long flags;
 381
 382         /** The request input */
 383         struct fuse_in in;
 384
 385         /** The request output */
 386         struct fuse_out out;
 387
 388         /** Used to wake up the task waiting for completion of request*/
 389         wait_queue_head_t waitq;
 390
 391         /** Data for asynchronous requests */
 392         union {
 393                 struct {
 394                         struct fuse_release_in in;
 395                         struct inode *inode;
 396                 } release;
 397                 struct fuse_init_in init_in;
 398                 struct fuse_init_out init_out;
 399                 struct cuse_init_in cuse_init_in;
 400                 struct {
 401                         struct fuse_read_in in;
 402                         u64 attr_ver;
 403                 } read;
 404                 struct {
 405                         struct fuse_write_in in;
 406                         struct fuse_write_out out;
 407                         struct fuse_req *next;
 408                 } write;
 409                 struct fuse_notify_retrieve_in retrieve_in;
 410         } misc;
 411
 412         /** page vector */
 413         struct page **pages;
 414
 415         /** page-descriptor vector */
 416         struct fuse_page_desc *page_descs;
 417
 418         /** size of the 'pages' array */
 419         unsigned max_pages;
 420
 421         /** inline page vector */
 422         struct page *inline_pages[FUSE_REQ_INLINE_PAGES];
 423
 424         /** inline page-descriptor vector */
 425         struct fuse_page_desc inline_page_descs[FUSE_REQ_INLINE_PAGES];
 426
 427         /** number of pages in vector */
 428         unsigned num_pages;
 429
 430         /** File used in the request (or NULL) */
 431         struct fuse_file *ff;
 432
 433         /** Inode used in the request or NULL */
 434         struct inode *inode;
 435
 436         /** AIO control block */
 437         struct fuse_io_priv *io;
 438
 439         /** Link on fi->writepages */
 440         struct list_head writepages_entry;
 441
 442         /** Request completion callback */
 443         void (*end)(struct fuse_conn *, struct fuse_req *);
 444
 445         /** Request is stolen from fuse_file->reserved_req */
 446         struct file *stolen_file;
 447 };
 448
 449 struct fuse_iqueue {
 450         /** Connection established */
 451         unsigned connected;
 452
 453         /** Readers of the connection are waiting on this */
 454         wait_queue_head_t waitq;
 455
 456         /** The next unique request id */
 457         u64 reqctr;
 458
 459         /** The list of pending requests */
 460         struct list_head pending;
 461
 462         /** Pending interrupts */
 463         struct list_head interrupts;
 464
 465         /** Queue of pending forgets */
 466         struct fuse_forget_link forget_list_head;
 467         struct fuse_forget_link *forget_list_tail;
 468
 469         /** Batching of FORGET requests (positive indicates FORGET batch) */
 470         int forget_batch;
 471
 472         /** O_ASYNC requests */
 473         struct fasync_struct *fasync;
 474 };
 475
 476 #define FUSE_PQ_HASH_BITS 8
 477 #define FUSE_PQ_HASH_SIZE (1 << FUSE_PQ_HASH_BITS)
 478
 479 struct fuse_pqueue {
 480         /** Connection established */
 481         unsigned connected;
 482
 483         /** Lock protecting accessess to  members of this structure */
 484         spinlock_t lock;
 485
 486         /** Hash table of requests being processed */
 487         struct list_head *processing;
 488
 489         /** The list of requests under I/O */
 490         struct list_head io;
 491 };
 492
 493 /**
 494  * Fuse device instance
 495  */
 496 struct fuse_dev {
 497         /** Fuse connection for this device */
 498         struct fuse_conn *fc;
 499
 500         /** Processing queue */
 501         struct fuse_pqueue pq;
 502
 503         /** list entry on fc->devices */
 504         struct list_head entry;
 505 };
 506
 507 /**
 508  * A Fuse connection.
 509  *
 510  * This structure is created, when the filesystem is mounted, and is
 511  * destroyed, when the client device is closed and the filesystem is
 512  * unmounted.
 513  */
 514 struct fuse_conn {
 515         /** Lock protecting accessess to  members of this structure */
 516         spinlock_t lock;
 517
 518         /** Refcount */
 519         refcount_t count;
 520
 521         /** Number of fuse_dev's */
 522         atomic_t dev_count;
 523
 524         struct rcu_head rcu;
 525
 526         /** The user id for this mount */
 527         kuid_t user_id;
 528
 529         /** The group id for this mount */
 530         kgid_t group_id;
 531
 532         /** The pid namespace for this mount */
 533         struct pid_namespace *pid_ns;
 534
 535         /** The user namespace for this mount */
 536         struct user_namespace *user_ns;
 537
 538         /** Maximum read size */
 539         unsigned max_read;
 540
 541         /** Maximum write size */
 542         unsigned max_write;
 543
 544         /** Maxmum number of pages that can be used in a single request */
 545         unsigned int max_pages;
 546
 547         /** Input queue */
 548         struct fuse_iqueue iq;
 549
 550         /** The next unique kernel file handle */
 551         atomic64_t khctr;
 552
 553         /** rbtree of fuse_files waiting for poll events indexed by ph */
 554         struct rb_root polled_files;
 555
 556         /** Maximum number of outstanding background requests */
 557         unsigned max_background;
 558
 559         /** Number of background requests at which congestion starts */
 560         unsigned congestion_threshold;
 561
 562         /** Number of requests currently in the background */
 563         unsigned num_background;
 564
 565         /** Number of background requests currently queued for userspace */
 566         unsigned active_background;
 567
 568         /** The list of background requests set aside for later queuing */
 569         struct list_head bg_queue;
 570
 571         /** Protects: max_background, congestion_threshold, num_background,
 572          * active_background, bg_queue, blocked */
 573         spinlock_t bg_lock;
 574
 575         /** Flag indicating that INIT reply has been received. Allocating
 576          * any fuse request will be suspended until the flag is set */
 577         int initialized;
 578
 579         /** Flag indicating if connection is blocked.  This will be
 580             the case before the INIT reply is received, and if there
 581             are too many outstading backgrounds requests */
 582         int blocked;
 583
 584         /** waitq for blocked connection */
 585         wait_queue_head_t blocked_waitq;
 586
 587         /** waitq for reserved requests */
 588         wait_queue_head_t reserved_req_waitq;
 589
 590         /** Connection established, cleared on umount, connection
 591             abort and device release */
 592         unsigned connected;
 593
 594         /** Connection aborted via sysfs */
 595         bool aborted;
 596
 597         /** Connection failed (version mismatch).  Cannot race with
 598             setting other bitfields since it is only set once in INIT
 599             reply, before any other request, and never cleared */
 600         unsigned conn_error:1;
 601
 602         /** Connection successful.  Only set in INIT */
 603         unsigned conn_init:1;
 604
 605         /** Do readpages asynchronously?  Only set in INIT */
 606         unsigned async_read:1;
 607
 608         /** Return an unique read error after abort.  Only set in INIT */
 609         unsigned abort_err:1;
 610
 611         /** Do not send separate SETATTR request before open(O_TRUNC)  */
 612         unsigned atomic_o_trunc:1;
 613
 614         /** Filesystem supports NFS exporting.  Only set in INIT */
 615         unsigned export_support:1;
 616
 617         /** write-back cache policy (default is write-through) */
 618         unsigned writeback_cache:1;
 619
 620         /** allow parallel lookups and readdir (default is serialized) */
 621         unsigned parallel_dirops:1;
 622
 623         /** handle fs handles killing suid/sgid/cap on write/chown/trunc */
 624         unsigned handle_killpriv:1;
 625
 626         /** cache READLINK responses in page cache */
 627         unsigned cache_symlinks:1;
 628
 629         /*
 630          * The following bitfields are only for optimization purposes
 631          * and hence races in setting them will not cause malfunction
 632          */
 633
 634         /** Is open/release not implemented by fs? */
 635         unsigned no_open:1;
 636
 637         /** Is opendir/releasedir not implemented by fs? */
 638         unsigned no_opendir:1;
 639
 640         /** Is fsync not implemented by fs? */
 641         unsigned no_fsync:1;
 642
 643         /** Is fsyncdir not implemented by fs? */
 644         unsigned no_fsyncdir:1;
 645
 646         /** Is flush not implemented by fs? */
 647         unsigned no_flush:1;
 648
 649         /** Is setxattr not implemented by fs? */
 650         unsigned no_setxattr:1;
 651
 652         /** Is getxattr not implemented by fs? */
 653         unsigned no_getxattr:1;
 654
 655         /** Is listxattr not implemented by fs? */
 656         unsigned no_listxattr:1;
 657
 658         /** Is removexattr not implemented by fs? */
 659         unsigned no_removexattr:1;
 660
 661         /** Are posix file locking primitives not implemented by fs? */
 662         unsigned no_lock:1;
 663
 664         /** Is access not implemented by fs? */
 665         unsigned no_access:1;
 666
 667         /** Is create not implemented by fs? */
 668         unsigned no_create:1;
 669
 670         /** Is interrupt not implemented by fs? */
 671         unsigned no_interrupt:1;
 672
 673         /** Is bmap not implemented by fs? */
 674         unsigned no_bmap:1;
 675
 676         /** Is poll not implemented by fs? */
 677         unsigned no_poll:1;
 678
 679         /** Do multi-page cached writes */
 680         unsigned big_writes:1;
 681
 682         /** Don't apply umask to creation modes */
 683         unsigned dont_mask:1;
 684
 685         /** Are BSD file locking primitives not implemented by fs? */
 686         unsigned no_flock:1;
 687
 688         /** Is fallocate not implemented by fs? */
 689         unsigned no_fallocate:1;
 690
 691         /** Is rename with flags implemented by fs? */
 692         unsigned no_rename2:1;
 693
 694         /** Use enhanced/automatic page cache invalidation. */
 695         unsigned auto_inval_data:1;
 696
 697         /** Filesystem is fully reponsible for page cache invalidation. */
 698         unsigned explicit_inval_data:1;
 699
 700         /** Does the filesystem support readdirplus? */
 701         unsigned do_readdirplus:1;
 702
 703         /** Does the filesystem want adaptive readdirplus? */
 704         unsigned readdirplus_auto:1;
 705
 706         /** Does the filesystem support asynchronous direct-IO submission? */
 707         unsigned async_dio:1;
 708
 709         /** Is lseek not implemented by fs? */
 710         unsigned no_lseek:1;
 711
 712         /** Does the filesystem support posix acls? */
 713         unsigned posix_acl:1;
 714
 715         /** Check permissions based on the file mode or not? */
 716         unsigned default_permissions:1;
 717
 718         /** Allow other than the mounter user to access the filesystem ? */
 719         unsigned allow_other:1;
 720
 721         /** Does the filesystem support copy_file_range? */
 722         unsigned no_copy_file_range:1;
 723
 724         /** The number of requests waiting for completion */
 725         atomic_t num_waiting;
 726
 727         /** Negotiated minor version */
 728         unsigned minor;
 729
 730         /** Entry on the fuse_conn_list */
 731         struct list_head entry;
 732
 733         /** Device ID from super block */
 734         dev_t dev;
 735
 736         /** Dentries in the control filesystem */
 737         struct dentry *ctl_dentry[FUSE_CTL_NUM_DENTRIES];
 738
 739         /** number of dentries used in the above array */
 740         int ctl_ndents;
 741
 742         /** Key for lock owner ID scrambling */
 743         u32 scramble_key[4];
 744
 745         /** Reserved request for the DESTROY message */
 746         struct fuse_req *destroy_req;
 747
 748         /** Version counter for attribute changes */
 749         atomic64_t attr_version;
 750
 751         /** Called on final put */
 752         void (*release)(struct fuse_conn *);
 753
 754         /** Super block for this connection. */
 755         struct super_block *sb;
 756
 757         /** Read/write semaphore to hold when accessing sb. */
 758         struct rw_semaphore killsb;
 759
 760         /** List of device instances belonging to this connection */
 761         struct list_head devices;
 762 };
 763
 764 static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb)
 765 {
 766         return sb->s_fs_info;
 767 }
 768
 769 static inline struct fuse_conn *get_fuse_conn(struct inode *inode)
 770 {
 771         return get_fuse_conn_super(inode->i_sb);
 772 }
 773
 774 static inline struct fuse_inode *get_fuse_inode(struct inode *inode)
 775 {
 776         return container_of(inode, struct fuse_inode, inode);
 777 }
 778
 779 static inline u64 get_node_id(struct inode *inode)
 780 {
 781         return get_fuse_inode(inode)->nodeid;
 782 }
 783
 784 static inline int invalid_nodeid(u64 nodeid)
 785 {
 786         return !nodeid || nodeid == FUSE_ROOT_ID;
 787 }
 788
 789 static inline u64 fuse_get_attr_version(struct fuse_conn *fc)
 790 {
 791         return atomic64_read(&fc->attr_version);
 792 }
 793
 794 /** Device operations */
 795 extern const struct file_operations fuse_dev_operations;
 796
 797 extern const struct dentry_operations fuse_dentry_operations;
 798 extern const struct dentry_operations fuse_root_dentry_operations;
 799
 800 /**
 801  * Inode to nodeid comparison.
 802  */
 803 int fuse_inode_eq(struct inode *inode, void *_nodeidp);
 804
 805 /**
 806  * Get a filled in inode
 807  */
 808 struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
 809                         int generation, struct fuse_attr *attr,
 810                         u64 attr_valid, u64 attr_version);
 811
 812 int fuse_lookup_name(struct super_block *sb, u64 nodeid, const struct qstr *name,
 813                      struct fuse_entry_out *outarg, struct inode **inode);
 814
 815 /**
 816  * Send FORGET command
 817  */
 818 void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget,
 819                        u64 nodeid, u64 nlookup);
 820
 821 struct fuse_forget_link *fuse_alloc_forget(void);
 822
 823 /* Used by READDIRPLUS */
 824 void fuse_force_forget(struct file *file, u64 nodeid);
 825
 826 /**
 827  * Initialize READ or READDIR request
 828  */
 829 void fuse_read_fill(struct fuse_req *req, struct file *file,
 830                     loff_t pos, size_t count, int opcode);
 831
 832 /**
 833  * Send OPEN or OPENDIR request
 834  */
 835 int fuse_open_common(struct inode *inode, struct file *file, bool isdir);
 836
 837 struct fuse_file *fuse_file_alloc(struct fuse_conn *fc);
 838 void fuse_file_free(struct fuse_file *ff);
 839 void fuse_finish_open(struct inode *inode, struct file *file);
 840
 841 void fuse_sync_release(struct fuse_inode *fi, struct fuse_file *ff, int flags);
 842
 843 /**
 844  * Send RELEASE or RELEASEDIR request
 845  */
 846 void fuse_release_common(struct file *file, bool isdir);
 847
 848 /**
 849  * Send FSYNC or FSYNCDIR request
 850  */
 851 int fuse_fsync_common(struct file *file, loff_t start, loff_t end,
 852                       int datasync, int opcode);
 853
 854 /**
 855  * Notify poll wakeup
 856  */
 857 int fuse_notify_poll_wakeup(struct fuse_conn *fc,
 858                             struct fuse_notify_poll_wakeup_out *outarg);
 859
 860 /**
 861  * Initialize file operations on a regular file
 862  */
 863 void fuse_init_file_inode(struct inode *inode);
 864
 865 /**
 866  * Initialize inode operations on regular files and special files
 867  */
 868 void fuse_init_common(struct inode *inode);
 869
 870 /**
 871  * Initialize inode and file operations on a directory
 872  */
 873 void fuse_init_dir(struct inode *inode);
 874
 875 /**
 876  * Initialize inode operations on a symlink
 877  */
 878 void fuse_init_symlink(struct inode *inode);
 879
 880 /**
 881  * Change attributes of an inode
 882  */
 883 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
 884                             u64 attr_valid, u64 attr_version);
 885
 886 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
 887                                    u64 attr_valid);
 888
 889 /**
 890  * Initialize the client device
 891  */
 892 int fuse_dev_init(void);
 893
 894 /**
 895  * Cleanup the client device
 896  */
 897 void fuse_dev_cleanup(void);
 898
 899 int fuse_ctl_init(void);
 900 void __exit fuse_ctl_cleanup(void);
 901
 902 /**
 903  * Allocate a request
 904  */
 905 struct fuse_req *fuse_request_alloc(unsigned npages);
 906
 907 struct fuse_req *fuse_request_alloc_nofs(unsigned npages);
 908
 909 bool fuse_req_realloc_pages(struct fuse_conn *fc, struct fuse_req *req,
 910                             gfp_t flags);
 911
 912
 913 /**
 914  * Free a request
 915  */
 916 void fuse_request_free(struct fuse_req *req);
 917
 918 /**
 919  * Get a request, may fail with -ENOMEM,
 920  * caller should specify # elements in req->pages[] explicitly
 921  */
 922 struct fuse_req *fuse_get_req(struct fuse_conn *fc, unsigned npages);
 923 struct fuse_req *fuse_get_req_for_background(struct fuse_conn *fc,
 924                                              unsigned npages);
 925
 926 /*
 927  * Increment reference count on request
 928  */
 929 void __fuse_get_request(struct fuse_req *req);
 930
 931 /**
 932  * Gets a requests for a file operation, always succeeds
 933  */
 934 struct fuse_req *fuse_get_req_nofail_nopages(struct fuse_conn *fc,
 935                                              struct file *file);
 936
 937 /**
 938  * Decrement reference count of a request.  If count goes to zero free
 939  * the request.
 940  */
 941 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req);
 942
 943 /**
 944  * Send a request (synchronous)
 945  */
 946 void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req);
 947
 948 /**
 949  * Simple request sending that does request allocation and freeing
 950  */
 951 ssize_t fuse_simple_request(struct fuse_conn *fc, struct fuse_args *args);
 952
 953 /**
 954  * Send a request in the background
 955  */
 956 void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req);
 957 bool fuse_request_queue_background(struct fuse_conn *fc, struct fuse_req *req);
 958
 959 /* Abort all requests */
 960 void fuse_abort_conn(struct fuse_conn *fc);
 961 void fuse_wait_aborted(struct fuse_conn *fc);
 962
 963 /**
 964  * Invalidate inode attributes
 965  */
 966 void fuse_invalidate_attr(struct inode *inode);
 967
 968 void fuse_invalidate_entry_cache(struct dentry *entry);
 969
 970 void fuse_invalidate_atime(struct inode *inode);
 971
 972 u64 entry_attr_timeout(struct fuse_entry_out *o);
 973 void fuse_change_entry_timeout(struct dentry *entry, struct fuse_entry_out *o);
 974
 975 /**
 976  * Acquire reference to fuse_conn
 977  */
 978 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc);
 979
 980 /**
 981  * Initialize fuse_conn
 982  */
 983 void fuse_conn_init(struct fuse_conn *fc, struct user_namespace *user_ns);
 984
 985 /**
 986  * Release reference to fuse_conn
 987  */
 988 void fuse_conn_put(struct fuse_conn *fc);
 989
 990 struct fuse_dev *fuse_dev_alloc(struct fuse_conn *fc);
 991 void fuse_dev_free(struct fuse_dev *fud);
 992
 993 /**
 994  * Add connection to control filesystem
 995  */
 996 int fuse_ctl_add_conn(struct fuse_conn *fc);
 997
 998 /**
 999  * Remove connection from control filesystem
1000  */
1001 void fuse_ctl_remove_conn(struct fuse_conn *fc);
1002
1003 /**
1004  * Is file type valid?
1005  */
1006 int fuse_valid_type(int m);
1007
1008 /**
1009  * Is current process allowed to perform filesystem operation?
1010  */
1011 int fuse_allow_current_process(struct fuse_conn *fc);
1012
1013 u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id);
1014
1015 void fuse_update_ctime(struct inode *inode);
1016
1017 int fuse_update_attributes(struct inode *inode, struct file *file);
1018
1019 void fuse_flush_writepages(struct inode *inode);
1020
1021 void fuse_set_nowrite(struct inode *inode);
1022 void fuse_release_nowrite(struct inode *inode);
1023
1024 /**
1025  * File-system tells the kernel to invalidate cache for the given node id.
1026  */
1027 int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid,
1028                              loff_t offset, loff_t len);
1029
1030 /**
1031  * File-system tells the kernel to invalidate parent attributes and
1032  * the dentry matching parent/name.
1033  *
1034  * If the child_nodeid is non-zero and:
1035  *    - matches the inode number for the dentry matching parent/name,
1036  *    - is not a mount point
1037  *    - is a file or oan empty directory
1038  * then the dentry is unhashed (d_delete()).
1039  */
1040 int fuse_reverse_inval_entry(struct super_block *sb, u64 parent_nodeid,
1041                              u64 child_nodeid, struct qstr *name);
1042
1043 int fuse_do_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
1044                  bool isdir);
1045
1046 /**
1047  * fuse_direct_io() flags
1048  */
1049
1050 /** If set, it is WRITE; otherwise - READ */
1051 #define FUSE_DIO_WRITE (1 << 0)
1052
1053 /** CUSE pass fuse_direct_io() a file which f_mapping->host is not from FUSE */
1054 #define FUSE_DIO_CUSE  (1 << 1)
1055
1056 ssize_t fuse_direct_io(struct fuse_io_priv *io, struct iov_iter *iter,
1057                        loff_t *ppos, int flags);
1058 long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
1059                    unsigned int flags);
1060 long fuse_ioctl_common(struct file *file, unsigned int cmd,
1061                        unsigned long arg, unsigned int flags);
1062 __poll_t fuse_file_poll(struct file *file, poll_table *wait);
1063 int fuse_dev_release(struct inode *inode, struct file *file);
1064
1065 bool fuse_write_update_size(struct inode *inode, loff_t pos);
1066
1067 int fuse_flush_times(struct inode *inode, struct fuse_file *ff);
1068 int fuse_write_inode(struct inode *inode, struct writeback_control *wbc);
1069
1070 int fuse_do_setattr(struct dentry *dentry, struct iattr *attr,
1071                     struct file *file);
1072
1073 void fuse_set_initialized(struct fuse_conn *fc);
1074
1075 void fuse_unlock_inode(struct inode *inode, bool locked);
1076 bool fuse_lock_inode(struct inode *inode);
1077
1078 int fuse_setxattr(struct inode *inode, const char *name, const void *value,
1079                   size_t size, int flags);
1080 ssize_t fuse_getxattr(struct inode *inode, const char *name, void *value,
1081                       size_t size);
1082 ssize_t fuse_listxattr(struct dentry *entry, char *list, size_t size);
1083 int fuse_removexattr(struct inode *inode, const char *name);
1084 extern const struct xattr_handler *fuse_xattr_handlers[];
1085 extern const struct xattr_handler *fuse_acl_xattr_handlers[];
1086 extern const struct xattr_handler *fuse_no_acl_xattr_handlers[];
1087
1088 struct posix_acl;
1089 struct posix_acl *fuse_get_acl(struct inode *inode, int type);
1090 int fuse_set_acl(struct inode *inode, struct posix_acl *acl, int type);
1091
1092
1093 /* readdir.c */
1094 int fuse_readdir(struct file *file, struct dir_context *ctx);
1095
1096 #endif /* _FS_FUSE_I_H */