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