summaryrefslogtreecommitdiffstats
path: root/fs/fuse/fuse_i.h
blob: aa75e2305b7587a8010c3aef405b44aa777f3ae3 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
/*
  FUSE: Filesystem in Userspace
  Copyright (C) 2001-2008  Miklos Szeredi <miklos@szeredi.hu>

  This program can be distributed under the terms of the GNU GPL.
  See the file COPYING.
*/

#ifndef _FS_FUSE_I_H
#define _FS_FUSE_I_H

#ifndef pr_fmt
# define pr_fmt(fmt) "fuse: " fmt
#endif

#include <linux/fuse.h>
#include <linux/fs.h>
#include <linux/mount.h>
#include <linux/wait.h>
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/mm.h>
#include <linux/backing-dev.h>
#include <linux/mutex.h>
#include <linux/rwsem.h>
#include <linux/rbtree.h>
#include <linux/poll.h>
#include <linux/workqueue.h>
#include <linux/kref.h>
#include <linux/xattr.h>
#include <linux/pid_namespace.h>
#include <linux/refcount.h>
#include <linux/user_namespace.h>

/** Default max number of pages that can be used in a single read request */
#define FUSE_DEFAULT_MAX_PAGES_PER_REQ 32

/** Maximum of max_pages received in init_out */
#define FUSE_MAX_MAX_PAGES 256

/** Bias for fi->writectr, meaning new writepages must not be sent */
#define FUSE_NOWRITE INT_MIN

/** It could be as large as PATH_MAX, but would that have any uses? */
#define FUSE_NAME_MAX 1024

/** Number of dentries for each connection in the control filesystem */
#define FUSE_CTL_NUM_DENTRIES 5

/** List of active connections */
extern struct list_head fuse_conn_list;

/** Global mutex protecting fuse_conn_list and the control filesystem */
extern struct mutex fuse_mutex;

/** Module parameters */
extern unsigned max_user_bgreq;
extern unsigned max_user_congthresh;

/* One forget request */
struct fuse_forget_link {
	struct fuse_forget_one forget_one;
	struct fuse_forget_link *next;
};

/** FUSE inode */
struct fuse_inode {
	/** Inode data */
	struct inode inode;

	/** Unique ID, which identifies the inode between userspace
	 * and kernel */
	u64 nodeid;

	/** Number of lookups on this inode */
	u64 nlookup;

	/** The request used for sending the FORGET message */
	struct fuse_forget_link *forget;

	/** Time in jiffies until the file attributes are valid */
	u64 i_time;

	/* Which attributes are invalid */
	u32 inval_mask;

	/** The sticky bit in inode->i_mode may have been removed, so
	    preserve the original mode */
	umode_t orig_i_mode;

	/** 64 bit inode number */
	u64 orig_ino;

	/** Version of last attribute change */
	u64 attr_version;

	union {
		/* Write related fields (regular file only) */
		struct {
			/* Files usable in writepage.  Protected by fi->lock */
			struct list_head write_files;

			/* Writepages pending on truncate or fsync */
			struct list_head queued_writes;

			/* Number of sent writes, a negative bias
			 * (FUSE_NOWRITE) means more writes are blocked */
			int writectr;

			/* Waitq for writepage completion */
			wait_queue_head_t page_waitq;

			/* List of writepage requestst (pending or sent) */
			struct list_head writepages;
		};

		/* readdir cache (directory only) */
		struct {
			/* true if fully cached */
			bool cached;

			/* size of cache */
			loff_t size;

			/* position at end of cache (position of next entry) */
			loff_t pos;

			/* version of the cache */
			u64 version;

			/* modification time of directory when cache was
			 * started */
			struct timespec64 mtime;

			/* iversion of directory when cache was started */
			u64 iversion;

			/* protects above fields */
			spinlock_t lock;
		} rdc;
	};

	/** Miscellaneous bits describing inode state */
	unsigned long state;

	/** Lock for serializing lookup and readdir for back compatibility*/
	struct mutex mutex;

	/** Lock to protect write related fields */
	spinlock_t lock;
};

/** FUSE inode state bits */
enum {
	/** Advise readdirplus  */
	FUSE_I_ADVISE_RDPLUS,
	/** Initialized with readdirplus */
	FUSE_I_INIT_RDPLUS,
	/** An operation changing file size is in progress  */
	FUSE_I_SIZE_UNSTABLE,
};

struct fuse_conn;
struct fuse_release_args;

/** FUSE specific file data */
struct fuse_file {
	/** Fuse connection for this file */
	struct fuse_conn *fc;

	/* Argument space reserved for release */
	struct fuse_release_args *release_args;

	/** Kernel file handle guaranteed to be unique */
	u64 kh;

	/** File handle used by userspace */
	u64 fh;

	/** Node id of this file */
	u64 nodeid;

	/** Refcount */
	refcount_t count;

	/** FOPEN_* flags returned by open */
	u32 open_flags;

	/** Entry on inode's write_files list */
	struct list_head write_entry;

	/* Readdir related */
	struct {
		/*
		 * Protects below fields against (crazy) parallel readdir on
		 * same open file.  Uncontended in the normal case.
		 */
		struct mutex lock;

		/* Dir stream position */
		loff_t pos;

		/* Offset in cache */
		loff_t cache_off;

		/* Version of cache we are reading */
		u64 version;

	} readdir;

	/** RB node to be linked on fuse_conn->polled_files */
	struct rb_node polled_node;

	/** Wait queue head for poll */
	wait_queue_head_t poll_wait;

	/** Has flock been performed on this file? */
	bool flock:1;
};

/** One input argument of a request */
struct fuse_in_arg {
	unsigned size;
	const void *value;
};

/** One output argument of a request */
struct fuse_arg {
	unsigned size;
	void *value;
};

/** FUSE page descriptor */
struct fuse_page_desc {
	unsigned int length;
	unsigned int offset;
};

struct fuse_args {
	uint64_t nodeid;
	uint32_t opcode;
	unsigned short in_numargs;
	unsigned short out_numargs;
	bool force:1;
	bool noreply:1;
	bool nocreds:1;
	bool in_pages:1;
	bool out_pages:1;
	bool out_argvar:1;
	bool page_zeroing:1;
	bool page_replace:1;
	struct fuse_in_arg in_args[3];
	struct fuse_arg out_args[2];
	void (*end)(struct fuse_conn *fc, struct fuse_args *args, int error);
};

struct fuse_args_pages {
	struct fuse_args args;
	struct page **pages;
	struct fuse_page_desc *descs;
	unsigned int num_pages;
};

#define FUSE_ARGS(args) struct fuse_args args = {}

/** The request IO state (for asynchronous processing) */
struct fuse_io_priv {
	struct kref refcnt;
	int async;
	spinlock_t lock;
	unsigned reqs;
	ssize_t bytes;
	size_t size;
	__u64 offset;
	bool write;
	bool should_dirty;
	int err;
	struct kiocb *iocb;
	struct completion *done;
	bool blocking;
};

#define FUSE_IO_PRIV_SYNC(i) \
{					\
	.refcnt = KREF_INIT(1),		\
	.async = 0,			\
	.iocb = i,			\
}

/**
 * Request flags
 *
 * FR_ISREPLY:		set if the request has reply
 * FR_FORCE:		force sending of the request even if interrupted
 * FR_BACKGROUND:	request is sent in the background
 * FR_WAITING:		request is counted as "waiting"
 * FR_ABORTED:		the request was aborted
 * FR_INTERRUPTED:	the request has been interrupted
 * FR_LOCKED:		data is being copied to/from the request
 * FR_PENDING:		request is not yet in userspace
 * FR_SENT:		request is in userspace, waiting for an answer
 * FR_FINISHED:		request is finished
 * FR_PRIVATE:		request is on private list
 */
enum fuse_req_flag {
	FR_ISREPLY,
	FR_FORCE,
	FR_BACKGROUND,
	FR_WAITING,
	FR_ABORTED,
	FR_INTERRUPTED,
	FR_LOCKED,
	FR_PENDING,
	FR_SENT,
	FR_FINISHED,
	FR_PRIVATE,
};

/**
 * A request to the client
 *
 * .waitq.lock protects the following fields:
 *   - FR_ABORTED
 *   - FR_LOCKED (may also be modified under fc->lock, tested under both)
 */
struct fuse_req {
	/** This can be on either pending processing or io lists in
	    fuse_conn */
	struct list_head list;

	/** Entry on the interrupts list  */
	struct list_head intr_entry;

	/* Input/output arguments */
	struct fuse_args *args;

	/** refcount */
	refcount_t count;

	/* Request flags, updated with test/set/clear_bit() */
	unsigned long flags;

	/* The request input header */
	struct {
		struct fuse_in_header h;
	} in;

	/* The request output header */
	struct {
		struct fuse_out_header h;
	} out;

	/** Used to wake up the task waiting for completion of request*/
	wait_queue_head_t waitq;

#if IS_ENABLED(CONFIG_VIRTIO_FS)
	/** virtio-fs's physically contiguous buffer for in and out args */
	void *argbuf;
#endif
};

struct fuse_iqueue;

/**
 * Input queue callbacks
 *
 * Input queue signalling is device-specific.  For example, the /dev/fuse file
 * uses fiq->waitq and fasync to wake processes that are waiting on queue
 * readiness.  These callbacks allow other device types to respond to input
 * queue activity.
 */
struct fuse_iqueue_ops {
	/**
	 * Signal that a forget has been queued
	 */
	void (*wake_forget_and_unlock)(struct fuse_iqueue *fiq)
		__releases(fiq->lock);

	/**
	 * Signal that an INTERRUPT request has been queued
	 */
	void (*wake_interrupt_and_unlock)(struct fuse_iqueue *fiq)
		__releases(fiq->lock);

	/**
	 * Signal that a request has been queued
	 */
	void (*wake_pending_and_unlock)(struct fuse_iqueue *fiq)
		__releases(fiq->lock);

	/**
	 * Clean up when fuse_iqueue is destroyed
	 */
	void (*release)(struct fuse_iqueue *fiq);
};

/** /dev/fuse input queue operations */
extern const struct fuse_iqueue_ops fuse_dev_fiq_ops;

struct fuse_iqueue {
	/** Connection established */
	unsigned connected;

	/** Lock protecting accesses to members of this structure */
	spinlock_t lock;

	/** Readers of the connection are waiting on this */
	wait_queue_head_t waitq;

	/** The next unique request id */
	u64 reqctr;

	/** The list of pending requests */
	struct list_head pending;

	/** Pending interrupts */
	struct list_head interrupts;

	/** Queue of pending forgets */
	struct fuse_forget_link forget_list_head;
	struct fuse_forget_link *forget_list_tail;

	/** Batching of FORGET requests (positive indicates FORGET batch) */
	int forget_batch;

	/** O_ASYNC requests */
	struct fasync_struct *fasync;

	/** Device-specific callbacks */
	const struct fuse_iqueue_ops *ops;

	/** Device-specific state */
	void *priv;
};

#define FUSE_PQ_HASH_BITS 8
#define FUSE_PQ_HASH_SIZE (1 << FUSE_PQ_HASH_BITS)

struct fuse_pqueue {
	/** Connection established */
	unsigned connected;

	/** Lock protecting accessess to  members of this structure */
	spinlock_t lock;

	/** Hash table of requests being processed */
	struct list_head *processing;

	/** The list of requests under I/O */
	struct list_head io;
};

/**
 * Fuse device instance
 */
struct fuse_dev {
	/** Fuse connection for this device */
	struct fuse_conn *fc;

	/** Processing queue */
	struct fuse_pqueue pq;

	/** list entry on fc->devices */
	struct list_head entry;
};

struct fuse_fs_context {
	int fd;
	unsigned int rootmode;
	kuid_t user_id;
	kgid_t group_id;
	bool is_bdev:1;
	bool fd_present:1;
	bool rootmode_present:1;
	bool user_id_present:1;
	bool group_id_present:1;
	bool default_permissions:1;
	bool allow_other:1;
	bool destroy:1;
	bool no_control:1;
	bool no_force_umount:1;
	bool no_mount_options:1;
	unsigned int max_read;
	unsigned int blksize;
	const char *subtype;

	/* fuse_dev pointer to fill in, should contain NULL on entry */
	void **fudptr;
};

/**
 * A Fuse connection.
 *
 * This structure is created, when the filesystem is mounted, and is
 * destroyed, when the client device is closed and the filesystem is
 * unmounted.
 */
struct fuse_conn {
	/** Lock protecting accessess to  members of this structure */
	spinlock_t lock;

	/** Refcount */
	refcount_t count;

	/** Number of fuse_dev's */
	atomic_t dev_count;

	struct rcu_head rcu;

	/** The user id for this mount */
	kuid_t user_id;

	/** The group id for this mount */
	kgid_t group_id;

	/** The pid namespace for this mount */
	struct pid_namespace *pid_ns;

	/** The user namespace for this mount */
	struct user_namespace *user_ns;

	/** Maximum read size */
	unsigned max_read;

	/** Maximum write size */
	unsigned max_write;

	/** Maxmum number of pages that can be used in a single request */
	unsigned int max_pages;

	/** Input queue */
	struct fuse_iqueue iq;

	/** The next unique kernel file handle */
	atomic64_t khctr;

	/** rbtree of fuse_files waiting for poll events indexed by ph */
	struct rb_root polled_files;

	/** Maximum number of outstanding background requests */
	unsigned max_background;

	/** Number of background requests at which congestion starts */
	unsigned congestion_threshold;

	/** Number of requests currently in the background */
	unsigned num_background;

	/** Number of background requests currently queued for userspace */
	unsigned active_background;

	/** The list of background requests set aside for later queuing */
	struct list_head bg_queue;

	/** Protects: max_background, congestion_threshold, num_background,
	 * active_background, bg_queue, blocked */
	spinlock_t bg_lock;

	/** Flag indicating that INIT reply has been received. Allocating
	 * any fuse request will be suspended until the flag is set */
	int initialized;

	/** Flag indicating if connection is blocked.  This will be
	    the case before the INIT reply is received, and if there
	    are too many outstading backgrounds requests */
	int blocked;

	/** waitq for blocked connection */
	wait_queue_head_t blocked_waitq;

	/** Connection established, cleared on umount, connection
	    abort and device release */
	unsigned connected;

	/** Connection aborted via sysfs */
	bool aborted;

	/** Connection failed (version mismatch).  Cannot race with
	    setting other bitfields since it is only set once in INIT
	    reply, before any other request, and never cleared */
	unsigned conn_error:1;

	/** Connection successful.  Only set in INIT */
	unsigned conn_init:1;

	/** Do readpages asynchronously?  Only set in INIT */
	unsigned async_read:1;

	/** Return an unique read error after abort.  Only set in INIT */
	unsigned abort_err:1;

	/** Do not send separate SETATTR request before open(O_TRUNC)  */
	unsigned atomic_o_trunc:1;

	/** Filesystem supports NFS exporting.  Only set in INIT */
	unsigned export_support:1;

	/** write-back cache policy (default is write-through) */
	unsigned writeback_cache:1;

	/** allow parallel lookups and readdir (default is serialized) */
	unsigned parallel_dirops:1;

	/** handle fs handles killing suid/sgid/cap on write/chown/trunc */
	unsigned handle_killpriv:1;

	/** cache READLINK responses in page cache */
	unsigned cache_symlinks:1;

	/*
	 * The following bitfields are only for optimization purposes
	 * and hence races in setting them will not cause malfunction
	 */

	/** Is open/release not implemented by fs? */
	unsigned no_open:1;

	/** Is opendir/releasedir not implemented by fs? */
	unsigned no_opendir:1;

	/** Is fsync not implemented by fs? */
	unsigned no_fsync:1;

	/** Is fsyncdir not implemented by fs? */
	unsigned no_fsyncdir:1;

	/** Is flush not implemented by fs? */
	unsigned no_flush:1;

	/** Is setxattr not implemented by fs? */
	unsigned no_setxattr:1;

	/** Is getxattr not implemented by fs? */
	unsigned no_getxattr:1;

	/** Is listxattr not implemented by fs? */
	unsigned no_listxattr:1;

	/** Is removexattr not implemented by fs? */
	unsigned no_removexattr:1;

	/** Are posix file locking primitives not implemented by fs? */
	unsigned no_lock:1;

	/** Is access not implemented by fs? */
	unsigned no_access:1;

	/** Is create not implemented by fs? */
	unsigned no_create:1;

	/** Is interrupt not implemented by fs? */
	unsigned no_interrupt:1;

	/** Is bmap not implemented by fs? */
	unsigned no_bmap:1;

	/** Is poll not implemented by fs? */
	unsigned no_poll:1;

	/** Do multi-page cached writes */
	unsigned big_writes:1;

	/** Don't apply umask to creation modes */
	unsigned dont_mask:1;

	/** Are BSD file locking primitives not implemented by fs? */
	unsigned no_flock:1;

	/** Is fallocate not implemented by fs? */
	unsigned no_fallocate:1;

	/** Is rename with flags implemented by fs? */
	unsigned no_rename2:1;

	/** Use enhanced/automatic page cache invalidation. */
	unsigned auto_inval_data:1;

	/** Filesystem is fully reponsible for page cache invalidation. */
	unsigned explicit_inval_data:1;

	/** Does the filesystem support readdirplus? */
	unsigned do_readdirplus:1;

	/** Does the filesystem want adaptive readdirplus? */
	unsigned readdirplus_auto:1;

	/** Does the filesystem support asynchronous direct-IO submission? */
	unsigned async_dio:1;

	/** Is lseek not implemented by fs? */
	unsigned no_lseek:1;

	/** Does the filesystem support posix acls? */
	unsigned posix_acl:1;

	/** Check permissions based on the file mode or not? */
	unsigned default_permissions:1;

	/** Allow other than the mounter user to access the filesystem ? */
	unsigned allow_other:1;

	/** Does the filesystem support copy_file_range? */
	unsigned no_copy_file_range:1;

	/* Send DESTROY request */
	unsigned int destroy:1;

	/* Delete dentries that have gone stale */
	unsigned int delete_stale:1;

	/** Do not create entry in fusectl fs */
	unsigned int no_control:1;

	/** Do not allow MNT_FORCE umount */
	unsigned int no_force_umount:1;

	/* Do not show mount options */
	unsigned int no_mount_options:1;

	/** The number of requests waiting for completion */
	atomic_t num_waiting;

	/** Negotiated minor version */
	unsigned minor;

	/** Entry on the fuse_conn_list */
	struct list_head entry;

	/** Device ID from super block */
	dev_t dev;

	/** Dentries in the control filesystem */
	struct dentry *ctl_dentry[FUSE_CTL_NUM_DENTRIES];

	/** number of dentries used in the above array */
	int ctl_ndents;

	/** Key for lock owner ID scrambling */
	u32 scramble_key[4];

	/** Version counter for attribute changes */
	atomic64_t attr_version;

	/** Called on final put */
	void (*release)(struct fuse_conn *);

	/** Super block for this connection. */
	struct super_block *sb;

	/** Read/write semaphore to hold when accessing sb. */
	struct rw_semaphore killsb;

	/** List of device instances belonging to this connection */
	struct list_head devices;
};

static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb)
{
	return sb->s_fs_info;
}

static inline struct fuse_conn *get_fuse_conn(struct inode *inode)
{
	return get_fuse_conn_super(inode->i_sb);
}

static inline struct fuse_inode *get_fuse_inode(struct inode *inode)
{
	return container_of(inode, struct fuse_inode, inode);
}

static inline u64 get_node_id(struct inode *inode)
{
	return get_fuse_inode(inode)->nodeid;
}

static inline int invalid_nodeid(u64 nodeid)
{
	return !nodeid || nodeid == FUSE_ROOT_ID;
}

static inline u64 fuse_get_attr_version(struct fuse_conn *fc)
{
	return atomic64_read(&fc->attr_version);
}

/** Device operations */
extern const struct file_operations fuse_dev_operations;

extern const struct dentry_operations fuse_dentry_operations;
extern const struct dentry_operations fuse_root_dentry_operations;

/**
 * Inode to nodeid comparison.
 */
int fuse_inode_eq(struct inode *inode, void *_nodeidp);

/**
 * Get a filled in inode
 */
struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
			int generation, struct fuse_attr *attr,
			u64 attr_valid, u64 attr_version);

int fuse_lookup_name(struct super_block *sb, u64 nodeid, const struct qstr *name,
		     struct fuse_entry_out *outarg, struct inode **inode);

/**
 * Send FORGET command
 */
void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget,
		       u64 nodeid, u64 nlookup);

struct fuse_forget_link *fuse_alloc_forget(void);

struct fuse_forget_link *fuse_dequeue_forget(struct fuse_iqueue *fiq,
					     unsigned int max,
					     unsigned int *countp);

/*
 * Initialize READ or READDIR request
 */
struct fuse_io_args {
	union {
		struct {
			struct fuse_read_in in;
			u64 attr_ver;
		} read;
		struct {
			struct fuse_write_in in;
			struct fuse_write_out out;
		} write;
	};
	struct fuse_args_pages ap;
	struct fuse_io_priv *io;
	struct fuse_file *ff;
};

void fuse_read_args_fill(struct fuse_io_args *ia, struct file *file, loff_t pos,
			 size_t count, int opcode);


/**
 * Send OPEN or OPENDIR request
 */
int fuse_open_common(struct inode *inode, struct file *file, bool isdir);

struct fuse_file *fuse_file_alloc(struct fuse_conn *fc);
void fuse_file_free(struct fuse_file *ff);
void fuse_finish_open(struct inode *inode, struct file *file);

void fuse_sync_release(struct fuse_inode *fi, struct fuse_file *ff, int flags);

/**
 * Send RELEASE or RELEASEDIR request
 */
void fuse_release_common(struct file *file, bool isdir);

/**
 * Send FSYNC or FSYNCDIR request
 */
int fuse_fsync_common(struct file *file, loff_t start, loff_t end,
		      int datasync, int opcode);

/**
 * Notify poll wakeup
 */
int fuse_notify_poll_wakeup(struct fuse_conn *fc,
			    struct fuse_notify_poll_wakeup_out *outarg);

/**
 * Initialize file operations on a regular file
 */
void fuse_init_file_inode(struct inode *inode);

/**
 * Initialize inode operations on regular files and special files
 */
void fuse_init_common(struct inode *inode);

/**
 * Initialize inode and file operations on a directory
 */
void fuse_init_dir(struct inode *inode);

/**
 * Initialize inode operations on a symlink
 */
void fuse_init_symlink(struct inode *inode);

/**
 * Change attributes of an inode
 */
void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
			    u64 attr_valid, u64 attr_version);

void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
				   u64 attr_valid);

/**
 * Initialize the client device
 */
int fuse_dev_init(void);

/**
 * Cleanup the client device
 */
void fuse_dev_cleanup(void);

int fuse_ctl_init(void);
void __exit fuse_ctl_cleanup(void);

/**
 * Simple request sending that does request allocation and freeing
 */
ssize_t fuse_simple_request(struct fuse_conn *fc, struct fuse_args *args);
int fuse_simple_background(struct fuse_conn *fc, struct fuse_args *args,
			   gfp_t gfp_flags);

/**
 * End a finished request
 */
void fuse_request_end(struct fuse_conn *fc, struct fuse_req *req);

/* Abort all requests */
void fuse_abort_conn(struct fuse_conn *fc);
void fuse_wait_aborted(struct fuse_conn *fc);

/**
 * Invalidate inode attributes
 */
void fuse_invalidate_attr(struct inode *inode);

void fuse_invalidate_entry_cache(struct dentry *entry);

void fuse_invalidate_atime(struct inode *inode);

u64 entry_attr_timeout(struct fuse_entry_out *o);
void fuse_change_entry_timeout(struct dentry *entry, struct fuse_entry_out *o);

/**
 * Acquire reference to fuse_conn
 */
struct fuse_conn *fuse_conn_get(struct fuse_conn *fc);

/**
 * Initialize fuse_conn
 */
void fuse_conn_init(struct fuse_conn *fc, struct user_namespace *user_ns,
		    const struct fuse_iqueue_ops *fiq_ops, void *fiq_priv);

/**
 * Release reference to fuse_conn
 */
void fuse_conn_put(struct fuse_conn *fc);

struct fuse_dev *fuse_dev_alloc_install(struct fuse_conn *fc);
struct fuse_dev *fuse_dev_alloc(void);
void fuse_dev_install(struct fuse_dev *fud, struct fuse_conn *fc);
void fuse_dev_free(struct fuse_dev *fud);
void fuse_send_init(struct fuse_conn *fc);

/**
 * Fill in superblock and initialize fuse connection
 * @sb: partially-initialized superblock to fill in
 * @ctx: mount context
 */
int fuse_fill_super_common(struct super_block *sb, struct fuse_fs_context *ctx);

/**
 * Disassociate fuse connection from superblock and kill the superblock
 *
 * Calls kill_anon_super(), do not use with bdev mounts.
 */
void fuse_kill_sb_anon(struct super_block *sb);

/**
 * Add connection to control filesystem
 */
int fuse_ctl_add_conn(struct fuse_conn *fc);

/**
 * Remove connection from control filesystem
 */
void fuse_ctl_remove_conn(struct fuse_conn *fc);

/**
 * Is file type valid?
 */
int fuse_valid_type(int m);

bool fuse_invalid_attr(struct fuse_attr *attr);

/**
 * Is current process allowed to perform filesystem operation?
 */
int fuse_allow_current_process(struct fuse_conn *fc);

u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id);

void fuse_update_ctime(struct inode *inode);

int fuse_update_attributes(struct inode *inode, struct file *file);

void fuse_flush_writepages(struct inode *inode);

void fuse_set_nowrite(struct inode *inode);
void fuse_release_nowrite(struct inode *inode);

/**
 * File-system tells the kernel to invalidate cache for the given node id.
 */
int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid,
			     loff_t offset, loff_t len);

/**
 * File-system tells the kernel to invalidate parent attributes and
 * the dentry matching parent/name.
 *
 * If the child_nodeid is non-zero and:
 *    - matches the inode number for the dentry matching parent/name,
 *    - is not a mount point
 *    - is a file or oan empty directory
 * then the dentry is unhashed (d_delete()).
 */
int fuse_reverse_inval_entry(struct super_block *sb, u64 parent_nodeid,
			     u64 child_nodeid, struct qstr *name);

int fuse_do_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
		 bool isdir);

/**
 * fuse_direct_io() flags
 */

/** If set, it is WRITE; otherwise - READ */
#define FUSE_DIO_WRITE (1 << 0)

/** CUSE pass fuse_direct_io() a file which f_mapping->host is not from FUSE */
#define FUSE_DIO_CUSE  (1 << 1)

ssize_t fuse_direct_io(struct fuse_io_priv *io, struct iov_iter *iter,
		       loff_t *ppos, int flags);
long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
		   unsigned int flags);
long fuse_ioctl_common(struct file *file, unsigned int cmd,
		       unsigned long arg, unsigned int flags);
__poll_t fuse_file_poll(struct file *file, poll_table *wait);
int fuse_dev_release(struct inode *inode, struct file *file);

bool fuse_write_update_size(struct inode *inode, loff_t pos);

int fuse_flush_times(struct inode *inode, struct fuse_file *ff);
int fuse_write_inode(struct inode *inode, struct writeback_control *wbc);

int fuse_do_setattr(struct dentry *dentry, struct iattr *attr,
		    struct file *file);

void fuse_set_initialized(struct fuse_conn *fc);

void fuse_unlock_inode(struct inode *inode, bool locked);
bool fuse_lock_inode(struct inode *inode);

int fuse_setxattr(struct inode *inode, const char *name, const void *value,
		  size_t size, int flags);
ssize_t fuse_getxattr(struct inode *inode, const char *name, void *value,
		      size_t size);
ssize_t fuse_listxattr(struct dentry *entry, char *list, size_t size);
int fuse_removexattr(struct inode *inode, const char *name);
extern const struct xattr_handler *fuse_xattr_handlers[];
extern const struct xattr_handler *fuse_acl_xattr_handlers[];
extern const struct xattr_handler *fuse_no_acl_xattr_handlers[];

struct posix_acl;
struct posix_acl *fuse_get_acl(struct inode *inode, int type);
int fuse_set_acl(struct inode *inode, struct posix_acl *acl, int type);


/* readdir.c */
int fuse_readdir(struct file *file, struct dir_context *ctx);

/**
 * Return the number of bytes in an arguments list
 */
unsigned int fuse_len_args(unsigned int numargs, struct fuse_arg *args);

/**
 * Get the next unique ID for a request
 */
u64 fuse_get_unique(struct fuse_iqueue *fiq);
void fuse_free_conn(struct fuse_conn *fc);

#endif /* _FS_FUSE_I_H */