xref: /openbmc/linux/fs/fuse/fuse_i.h (revision f0702555)
1 /*
2   FUSE: Filesystem in Userspace
3   Copyright (C) 2001-2008  Miklos Szeredi <miklos@szeredi.hu>
4 
5   This program can be distributed under the terms of the GNU GPL.
6   See the file COPYING.
7 */
8 
9 #ifndef _FS_FUSE_I_H
10 #define _FS_FUSE_I_H
11 
12 #include <linux/fuse.h>
13 #include <linux/fs.h>
14 #include <linux/mount.h>
15 #include <linux/wait.h>
16 #include <linux/list.h>
17 #include <linux/spinlock.h>
18 #include <linux/mm.h>
19 #include <linux/backing-dev.h>
20 #include <linux/mutex.h>
21 #include <linux/rwsem.h>
22 #include <linux/rbtree.h>
23 #include <linux/poll.h>
24 #include <linux/workqueue.h>
25 #include <linux/kref.h>
26 
27 /** Max number of pages that can be used in a single read request */
28 #define FUSE_MAX_PAGES_PER_REQ 32
29 
30 /** Bias for fi->writectr, meaning new writepages must not be sent */
31 #define FUSE_NOWRITE INT_MIN
32 
33 /** It could be as large as PATH_MAX, but would that have any uses? */
34 #define FUSE_NAME_MAX 1024
35 
36 /** Number of dentries for each connection in the control filesystem */
37 #define FUSE_CTL_NUM_DENTRIES 5
38 
39 /** If the FUSE_DEFAULT_PERMISSIONS flag is given, the filesystem
40     module will check permissions based on the file mode.  Otherwise no
41     permission checking is done in the kernel */
42 #define FUSE_DEFAULT_PERMISSIONS (1 << 0)
43 
44 /** If the FUSE_ALLOW_OTHER flag is given, then not only the user
45     doing the mount will be allowed to access the filesystem */
46 #define FUSE_ALLOW_OTHER         (1 << 1)
47 
48 /** Number of page pointers embedded in fuse_req */
49 #define FUSE_REQ_INLINE_PAGES 1
50 
51 /** List of active connections */
52 extern struct list_head fuse_conn_list;
53 
54 /** Global mutex protecting fuse_conn_list and the control filesystem */
55 extern struct mutex fuse_mutex;
56 
57 /** Module parameters */
58 extern unsigned max_user_bgreq;
59 extern unsigned max_user_congthresh;
60 
61 /* One forget request */
62 struct fuse_forget_link {
63 	struct fuse_forget_one forget_one;
64 	struct fuse_forget_link *next;
65 };
66 
67 /** FUSE inode */
68 struct fuse_inode {
69 	/** Inode data */
70 	struct inode inode;
71 
72 	/** Unique ID, which identifies the inode between userspace
73 	 * and kernel */
74 	u64 nodeid;
75 
76 	/** Number of lookups on this inode */
77 	u64 nlookup;
78 
79 	/** The request used for sending the FORGET message */
80 	struct fuse_forget_link *forget;
81 
82 	/** Time in jiffies until the file attributes are valid */
83 	u64 i_time;
84 
85 	/** The sticky bit in inode->i_mode may have been removed, so
86 	    preserve the original mode */
87 	umode_t orig_i_mode;
88 
89 	/** 64 bit inode number */
90 	u64 orig_ino;
91 
92 	/** Version of last attribute change */
93 	u64 attr_version;
94 
95 	/** Files usable in writepage.  Protected by fc->lock */
96 	struct list_head write_files;
97 
98 	/** Writepages pending on truncate or fsync */
99 	struct list_head queued_writes;
100 
101 	/** Number of sent writes, a negative bias (FUSE_NOWRITE)
102 	 * means more writes are blocked */
103 	int writectr;
104 
105 	/** Waitq for writepage completion */
106 	wait_queue_head_t page_waitq;
107 
108 	/** List of writepage requestst (pending or sent) */
109 	struct list_head writepages;
110 
111 	/** Miscellaneous bits describing inode state */
112 	unsigned long state;
113 };
114 
115 /** FUSE inode state bits */
116 enum {
117 	/** Advise readdirplus  */
118 	FUSE_I_ADVISE_RDPLUS,
119 	/** Initialized with readdirplus */
120 	FUSE_I_INIT_RDPLUS,
121 	/** An operation changing file size is in progress  */
122 	FUSE_I_SIZE_UNSTABLE,
123 };
124 
125 struct fuse_conn;
126 
127 /** FUSE specific file data */
128 struct fuse_file {
129 	/** Fuse connection for this file */
130 	struct fuse_conn *fc;
131 
132 	/** Request reserved for flush and release */
133 	struct fuse_req *reserved_req;
134 
135 	/** Kernel file handle guaranteed to be unique */
136 	u64 kh;
137 
138 	/** File handle used by userspace */
139 	u64 fh;
140 
141 	/** Node id of this file */
142 	u64 nodeid;
143 
144 	/** Refcount */
145 	atomic_t count;
146 
147 	/** FOPEN_* flags returned by open */
148 	u32 open_flags;
149 
150 	/** Entry on inode's write_files list */
151 	struct list_head write_entry;
152 
153 	/** RB node to be linked on fuse_conn->polled_files */
154 	struct rb_node polled_node;
155 
156 	/** Wait queue head for poll */
157 	wait_queue_head_t poll_wait;
158 
159 	/** Has flock been performed on this file? */
160 	bool flock:1;
161 };
162 
163 /** One input argument of a request */
164 struct fuse_in_arg {
165 	unsigned size;
166 	const void *value;
167 };
168 
169 /** The request input */
170 struct fuse_in {
171 	/** The request header */
172 	struct fuse_in_header h;
173 
174 	/** True if the data for the last argument is in req->pages */
175 	unsigned argpages:1;
176 
177 	/** Number of arguments */
178 	unsigned numargs;
179 
180 	/** Array of arguments */
181 	struct fuse_in_arg args[3];
182 };
183 
184 /** One output argument of a request */
185 struct fuse_arg {
186 	unsigned size;
187 	void *value;
188 };
189 
190 /** The request output */
191 struct fuse_out {
192 	/** Header returned from userspace */
193 	struct fuse_out_header h;
194 
195 	/*
196 	 * The following bitfields are not changed during the request
197 	 * processing
198 	 */
199 
200 	/** Last argument is variable length (can be shorter than
201 	    arg->size) */
202 	unsigned argvar:1;
203 
204 	/** Last argument is a list of pages to copy data to */
205 	unsigned argpages:1;
206 
207 	/** Zero partially or not copied pages */
208 	unsigned page_zeroing:1;
209 
210 	/** Pages may be replaced with new ones */
211 	unsigned page_replace:1;
212 
213 	/** Number or arguments */
214 	unsigned numargs;
215 
216 	/** Array of arguments */
217 	struct fuse_arg args[2];
218 };
219 
220 /** FUSE page descriptor */
221 struct fuse_page_desc {
222 	unsigned int length;
223 	unsigned int offset;
224 };
225 
226 struct fuse_args {
227 	struct {
228 		struct {
229 			uint32_t opcode;
230 			uint64_t nodeid;
231 		} h;
232 		unsigned numargs;
233 		struct fuse_in_arg args[3];
234 
235 	} in;
236 	struct {
237 		unsigned argvar:1;
238 		unsigned numargs;
239 		struct fuse_arg args[2];
240 	} out;
241 };
242 
243 #define FUSE_ARGS(args) struct fuse_args args = {}
244 
245 /** The request IO state (for asynchronous processing) */
246 struct fuse_io_priv {
247 	struct kref refcnt;
248 	int async;
249 	spinlock_t lock;
250 	unsigned reqs;
251 	ssize_t bytes;
252 	size_t size;
253 	__u64 offset;
254 	bool write;
255 	int err;
256 	struct kiocb *iocb;
257 	struct file *file;
258 	struct completion *done;
259 };
260 
261 #define FUSE_IO_PRIV_SYNC(f) \
262 {					\
263 	.refcnt = { ATOMIC_INIT(1) },	\
264 	.async = 0,			\
265 	.file = f,			\
266 }
267 
268 /**
269  * Request flags
270  *
271  * FR_ISREPLY:		set if the request has reply
272  * FR_FORCE:		force sending of the request even if interrupted
273  * FR_BACKGROUND:	request is sent in the background
274  * FR_WAITING:		request is counted as "waiting"
275  * FR_ABORTED:		the request was aborted
276  * FR_INTERRUPTED:	the request has been interrupted
277  * FR_LOCKED:		data is being copied to/from the request
278  * FR_PENDING:		request is not yet in userspace
279  * FR_SENT:		request is in userspace, waiting for an answer
280  * FR_FINISHED:		request is finished
281  * FR_PRIVATE:		request is on private list
282  */
283 enum fuse_req_flag {
284 	FR_ISREPLY,
285 	FR_FORCE,
286 	FR_BACKGROUND,
287 	FR_WAITING,
288 	FR_ABORTED,
289 	FR_INTERRUPTED,
290 	FR_LOCKED,
291 	FR_PENDING,
292 	FR_SENT,
293 	FR_FINISHED,
294 	FR_PRIVATE,
295 };
296 
297 /**
298  * A request to the client
299  *
300  * .waitq.lock protects the following fields:
301  *   - FR_ABORTED
302  *   - FR_LOCKED (may also be modified under fc->lock, tested under both)
303  */
304 struct fuse_req {
305 	/** This can be on either pending processing or io lists in
306 	    fuse_conn */
307 	struct list_head list;
308 
309 	/** Entry on the interrupts list  */
310 	struct list_head intr_entry;
311 
312 	/** refcount */
313 	atomic_t count;
314 
315 	/** Unique ID for the interrupt request */
316 	u64 intr_unique;
317 
318 	/* Request flags, updated with test/set/clear_bit() */
319 	unsigned long flags;
320 
321 	/** The request input */
322 	struct fuse_in in;
323 
324 	/** The request output */
325 	struct fuse_out out;
326 
327 	/** Used to wake up the task waiting for completion of request*/
328 	wait_queue_head_t waitq;
329 
330 	/** Data for asynchronous requests */
331 	union {
332 		struct {
333 			struct fuse_release_in in;
334 			struct inode *inode;
335 		} release;
336 		struct fuse_init_in init_in;
337 		struct fuse_init_out init_out;
338 		struct cuse_init_in cuse_init_in;
339 		struct {
340 			struct fuse_read_in in;
341 			u64 attr_ver;
342 		} read;
343 		struct {
344 			struct fuse_write_in in;
345 			struct fuse_write_out out;
346 			struct fuse_req *next;
347 		} write;
348 		struct fuse_notify_retrieve_in retrieve_in;
349 	} misc;
350 
351 	/** page vector */
352 	struct page **pages;
353 
354 	/** page-descriptor vector */
355 	struct fuse_page_desc *page_descs;
356 
357 	/** size of the 'pages' array */
358 	unsigned max_pages;
359 
360 	/** inline page vector */
361 	struct page *inline_pages[FUSE_REQ_INLINE_PAGES];
362 
363 	/** inline page-descriptor vector */
364 	struct fuse_page_desc inline_page_descs[FUSE_REQ_INLINE_PAGES];
365 
366 	/** number of pages in vector */
367 	unsigned num_pages;
368 
369 	/** File used in the request (or NULL) */
370 	struct fuse_file *ff;
371 
372 	/** Inode used in the request or NULL */
373 	struct inode *inode;
374 
375 	/** AIO control block */
376 	struct fuse_io_priv *io;
377 
378 	/** Link on fi->writepages */
379 	struct list_head writepages_entry;
380 
381 	/** Request completion callback */
382 	void (*end)(struct fuse_conn *, struct fuse_req *);
383 
384 	/** Request is stolen from fuse_file->reserved_req */
385 	struct file *stolen_file;
386 };
387 
388 struct fuse_iqueue {
389 	/** Connection established */
390 	unsigned connected;
391 
392 	/** Readers of the connection are waiting on this */
393 	wait_queue_head_t waitq;
394 
395 	/** The next unique request id */
396 	u64 reqctr;
397 
398 	/** The list of pending requests */
399 	struct list_head pending;
400 
401 	/** Pending interrupts */
402 	struct list_head interrupts;
403 
404 	/** Queue of pending forgets */
405 	struct fuse_forget_link forget_list_head;
406 	struct fuse_forget_link *forget_list_tail;
407 
408 	/** Batching of FORGET requests (positive indicates FORGET batch) */
409 	int forget_batch;
410 
411 	/** O_ASYNC requests */
412 	struct fasync_struct *fasync;
413 };
414 
415 struct fuse_pqueue {
416 	/** Connection established */
417 	unsigned connected;
418 
419 	/** Lock protecting accessess to  members of this structure */
420 	spinlock_t lock;
421 
422 	/** The list of requests being processed */
423 	struct list_head processing;
424 
425 	/** The list of requests under I/O */
426 	struct list_head io;
427 };
428 
429 /**
430  * Fuse device instance
431  */
432 struct fuse_dev {
433 	/** Fuse connection for this device */
434 	struct fuse_conn *fc;
435 
436 	/** Processing queue */
437 	struct fuse_pqueue pq;
438 
439 	/** list entry on fc->devices */
440 	struct list_head entry;
441 };
442 
443 /**
444  * A Fuse connection.
445  *
446  * This structure is created, when the filesystem is mounted, and is
447  * destroyed, when the client device is closed and the filesystem is
448  * unmounted.
449  */
450 struct fuse_conn {
451 	/** Lock protecting accessess to  members of this structure */
452 	spinlock_t lock;
453 
454 	/** Refcount */
455 	atomic_t count;
456 
457 	/** Number of fuse_dev's */
458 	atomic_t dev_count;
459 
460 	struct rcu_head rcu;
461 
462 	/** The user id for this mount */
463 	kuid_t user_id;
464 
465 	/** The group id for this mount */
466 	kgid_t group_id;
467 
468 	/** The fuse mount flags for this mount */
469 	unsigned flags;
470 
471 	/** Maximum read size */
472 	unsigned max_read;
473 
474 	/** Maximum write size */
475 	unsigned max_write;
476 
477 	/** Input queue */
478 	struct fuse_iqueue iq;
479 
480 	/** The next unique kernel file handle */
481 	u64 khctr;
482 
483 	/** rbtree of fuse_files waiting for poll events indexed by ph */
484 	struct rb_root polled_files;
485 
486 	/** Maximum number of outstanding background requests */
487 	unsigned max_background;
488 
489 	/** Number of background requests at which congestion starts */
490 	unsigned congestion_threshold;
491 
492 	/** Number of requests currently in the background */
493 	unsigned num_background;
494 
495 	/** Number of background requests currently queued for userspace */
496 	unsigned active_background;
497 
498 	/** The list of background requests set aside for later queuing */
499 	struct list_head bg_queue;
500 
501 	/** Flag indicating that INIT reply has been received. Allocating
502 	 * any fuse request will be suspended until the flag is set */
503 	int initialized;
504 
505 	/** Flag indicating if connection is blocked.  This will be
506 	    the case before the INIT reply is received, and if there
507 	    are too many outstading backgrounds requests */
508 	int blocked;
509 
510 	/** waitq for blocked connection */
511 	wait_queue_head_t blocked_waitq;
512 
513 	/** waitq for reserved requests */
514 	wait_queue_head_t reserved_req_waitq;
515 
516 	/** Connection established, cleared on umount, connection
517 	    abort and device release */
518 	unsigned connected;
519 
520 	/** Connection failed (version mismatch).  Cannot race with
521 	    setting other bitfields since it is only set once in INIT
522 	    reply, before any other request, and never cleared */
523 	unsigned conn_error:1;
524 
525 	/** Connection successful.  Only set in INIT */
526 	unsigned conn_init:1;
527 
528 	/** Do readpages asynchronously?  Only set in INIT */
529 	unsigned async_read:1;
530 
531 	/** Do not send separate SETATTR request before open(O_TRUNC)  */
532 	unsigned atomic_o_trunc:1;
533 
534 	/** Filesystem supports NFS exporting.  Only set in INIT */
535 	unsigned export_support:1;
536 
537 	/** Set if bdi is valid */
538 	unsigned bdi_initialized:1;
539 
540 	/** write-back cache policy (default is write-through) */
541 	unsigned writeback_cache:1;
542 
543 	/*
544 	 * The following bitfields are only for optimization purposes
545 	 * and hence races in setting them will not cause malfunction
546 	 */
547 
548 	/** Is open/release not implemented by fs? */
549 	unsigned no_open:1;
550 
551 	/** Is fsync not implemented by fs? */
552 	unsigned no_fsync:1;
553 
554 	/** Is fsyncdir not implemented by fs? */
555 	unsigned no_fsyncdir:1;
556 
557 	/** Is flush not implemented by fs? */
558 	unsigned no_flush:1;
559 
560 	/** Is setxattr not implemented by fs? */
561 	unsigned no_setxattr:1;
562 
563 	/** Is getxattr not implemented by fs? */
564 	unsigned no_getxattr:1;
565 
566 	/** Is listxattr not implemented by fs? */
567 	unsigned no_listxattr:1;
568 
569 	/** Is removexattr not implemented by fs? */
570 	unsigned no_removexattr:1;
571 
572 	/** Are posix file locking primitives not implemented by fs? */
573 	unsigned no_lock:1;
574 
575 	/** Is access not implemented by fs? */
576 	unsigned no_access:1;
577 
578 	/** Is create not implemented by fs? */
579 	unsigned no_create:1;
580 
581 	/** Is interrupt not implemented by fs? */
582 	unsigned no_interrupt:1;
583 
584 	/** Is bmap not implemented by fs? */
585 	unsigned no_bmap:1;
586 
587 	/** Is poll not implemented by fs? */
588 	unsigned no_poll:1;
589 
590 	/** Do multi-page cached writes */
591 	unsigned big_writes:1;
592 
593 	/** Don't apply umask to creation modes */
594 	unsigned dont_mask:1;
595 
596 	/** Are BSD file locking primitives not implemented by fs? */
597 	unsigned no_flock:1;
598 
599 	/** Is fallocate not implemented by fs? */
600 	unsigned no_fallocate:1;
601 
602 	/** Is rename with flags implemented by fs? */
603 	unsigned no_rename2:1;
604 
605 	/** Use enhanced/automatic page cache invalidation. */
606 	unsigned auto_inval_data:1;
607 
608 	/** Does the filesystem support readdirplus? */
609 	unsigned do_readdirplus:1;
610 
611 	/** Does the filesystem want adaptive readdirplus? */
612 	unsigned readdirplus_auto:1;
613 
614 	/** Does the filesystem support asynchronous direct-IO submission? */
615 	unsigned async_dio:1;
616 
617 	/** Is lseek not implemented by fs? */
618 	unsigned no_lseek:1;
619 
620 	/** The number of requests waiting for completion */
621 	atomic_t num_waiting;
622 
623 	/** Negotiated minor version */
624 	unsigned minor;
625 
626 	/** Backing dev info */
627 	struct backing_dev_info bdi;
628 
629 	/** Entry on the fuse_conn_list */
630 	struct list_head entry;
631 
632 	/** Device ID from super block */
633 	dev_t dev;
634 
635 	/** Dentries in the control filesystem */
636 	struct dentry *ctl_dentry[FUSE_CTL_NUM_DENTRIES];
637 
638 	/** number of dentries used in the above array */
639 	int ctl_ndents;
640 
641 	/** Key for lock owner ID scrambling */
642 	u32 scramble_key[4];
643 
644 	/** Reserved request for the DESTROY message */
645 	struct fuse_req *destroy_req;
646 
647 	/** Version counter for attribute changes */
648 	u64 attr_version;
649 
650 	/** Called on final put */
651 	void (*release)(struct fuse_conn *);
652 
653 	/** Super block for this connection. */
654 	struct super_block *sb;
655 
656 	/** Read/write semaphore to hold when accessing sb. */
657 	struct rw_semaphore killsb;
658 
659 	/** List of device instances belonging to this connection */
660 	struct list_head devices;
661 };
662 
663 static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb)
664 {
665 	return sb->s_fs_info;
666 }
667 
668 static inline struct fuse_conn *get_fuse_conn(struct inode *inode)
669 {
670 	return get_fuse_conn_super(inode->i_sb);
671 }
672 
673 static inline struct fuse_inode *get_fuse_inode(struct inode *inode)
674 {
675 	return container_of(inode, struct fuse_inode, inode);
676 }
677 
678 static inline u64 get_node_id(struct inode *inode)
679 {
680 	return get_fuse_inode(inode)->nodeid;
681 }
682 
683 /** Device operations */
684 extern const struct file_operations fuse_dev_operations;
685 
686 extern const struct dentry_operations fuse_dentry_operations;
687 
688 /**
689  * Inode to nodeid comparison.
690  */
691 int fuse_inode_eq(struct inode *inode, void *_nodeidp);
692 
693 /**
694  * Get a filled in inode
695  */
696 struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
697 			int generation, struct fuse_attr *attr,
698 			u64 attr_valid, u64 attr_version);
699 
700 int fuse_lookup_name(struct super_block *sb, u64 nodeid, struct qstr *name,
701 		     struct fuse_entry_out *outarg, struct inode **inode);
702 
703 /**
704  * Send FORGET command
705  */
706 void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget,
707 		       u64 nodeid, u64 nlookup);
708 
709 struct fuse_forget_link *fuse_alloc_forget(void);
710 
711 /* Used by READDIRPLUS */
712 void fuse_force_forget(struct file *file, u64 nodeid);
713 
714 /**
715  * Initialize READ or READDIR request
716  */
717 void fuse_read_fill(struct fuse_req *req, struct file *file,
718 		    loff_t pos, size_t count, int opcode);
719 
720 /**
721  * Send OPEN or OPENDIR request
722  */
723 int fuse_open_common(struct inode *inode, struct file *file, bool isdir);
724 
725 struct fuse_file *fuse_file_alloc(struct fuse_conn *fc);
726 struct fuse_file *fuse_file_get(struct fuse_file *ff);
727 void fuse_file_free(struct fuse_file *ff);
728 void fuse_finish_open(struct inode *inode, struct file *file);
729 
730 void fuse_sync_release(struct fuse_file *ff, int flags);
731 
732 /**
733  * Send RELEASE or RELEASEDIR request
734  */
735 void fuse_release_common(struct file *file, int opcode);
736 
737 /**
738  * Send FSYNC or FSYNCDIR request
739  */
740 int fuse_fsync_common(struct file *file, loff_t start, loff_t end,
741 		      int datasync, int isdir);
742 
743 /**
744  * Notify poll wakeup
745  */
746 int fuse_notify_poll_wakeup(struct fuse_conn *fc,
747 			    struct fuse_notify_poll_wakeup_out *outarg);
748 
749 /**
750  * Initialize file operations on a regular file
751  */
752 void fuse_init_file_inode(struct inode *inode);
753 
754 /**
755  * Initialize inode operations on regular files and special files
756  */
757 void fuse_init_common(struct inode *inode);
758 
759 /**
760  * Initialize inode and file operations on a directory
761  */
762 void fuse_init_dir(struct inode *inode);
763 
764 /**
765  * Initialize inode operations on a symlink
766  */
767 void fuse_init_symlink(struct inode *inode);
768 
769 /**
770  * Change attributes of an inode
771  */
772 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
773 			    u64 attr_valid, u64 attr_version);
774 
775 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
776 				   u64 attr_valid);
777 
778 /**
779  * Initialize the client device
780  */
781 int fuse_dev_init(void);
782 
783 /**
784  * Cleanup the client device
785  */
786 void fuse_dev_cleanup(void);
787 
788 int fuse_ctl_init(void);
789 void __exit fuse_ctl_cleanup(void);
790 
791 /**
792  * Allocate a request
793  */
794 struct fuse_req *fuse_request_alloc(unsigned npages);
795 
796 struct fuse_req *fuse_request_alloc_nofs(unsigned npages);
797 
798 /**
799  * Free a request
800  */
801 void fuse_request_free(struct fuse_req *req);
802 
803 /**
804  * Get a request, may fail with -ENOMEM,
805  * caller should specify # elements in req->pages[] explicitly
806  */
807 struct fuse_req *fuse_get_req(struct fuse_conn *fc, unsigned npages);
808 struct fuse_req *fuse_get_req_for_background(struct fuse_conn *fc,
809 					     unsigned npages);
810 
811 /*
812  * Increment reference count on request
813  */
814 void __fuse_get_request(struct fuse_req *req);
815 
816 /**
817  * Gets a requests for a file operation, always succeeds
818  */
819 struct fuse_req *fuse_get_req_nofail_nopages(struct fuse_conn *fc,
820 					     struct file *file);
821 
822 /**
823  * Decrement reference count of a request.  If count goes to zero free
824  * the request.
825  */
826 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req);
827 
828 /**
829  * Send a request (synchronous)
830  */
831 void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req);
832 
833 /**
834  * Simple request sending that does request allocation and freeing
835  */
836 ssize_t fuse_simple_request(struct fuse_conn *fc, struct fuse_args *args);
837 
838 /**
839  * Send a request in the background
840  */
841 void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req);
842 
843 void fuse_request_send_background_locked(struct fuse_conn *fc,
844 					 struct fuse_req *req);
845 
846 /* Abort all requests */
847 void fuse_abort_conn(struct fuse_conn *fc);
848 
849 /**
850  * Invalidate inode attributes
851  */
852 void fuse_invalidate_attr(struct inode *inode);
853 
854 void fuse_invalidate_entry_cache(struct dentry *entry);
855 
856 void fuse_invalidate_atime(struct inode *inode);
857 
858 /**
859  * Acquire reference to fuse_conn
860  */
861 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc);
862 
863 /**
864  * Initialize fuse_conn
865  */
866 void fuse_conn_init(struct fuse_conn *fc);
867 
868 /**
869  * Release reference to fuse_conn
870  */
871 void fuse_conn_put(struct fuse_conn *fc);
872 
873 struct fuse_dev *fuse_dev_alloc(struct fuse_conn *fc);
874 void fuse_dev_free(struct fuse_dev *fud);
875 
876 /**
877  * Add connection to control filesystem
878  */
879 int fuse_ctl_add_conn(struct fuse_conn *fc);
880 
881 /**
882  * Remove connection from control filesystem
883  */
884 void fuse_ctl_remove_conn(struct fuse_conn *fc);
885 
886 /**
887  * Is file type valid?
888  */
889 int fuse_valid_type(int m);
890 
891 /**
892  * Is current process allowed to perform filesystem operation?
893  */
894 int fuse_allow_current_process(struct fuse_conn *fc);
895 
896 u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id);
897 
898 int fuse_update_attributes(struct inode *inode, struct kstat *stat,
899 			   struct file *file, bool *refreshed);
900 
901 void fuse_flush_writepages(struct inode *inode);
902 
903 void fuse_set_nowrite(struct inode *inode);
904 void fuse_release_nowrite(struct inode *inode);
905 
906 u64 fuse_get_attr_version(struct fuse_conn *fc);
907 
908 /**
909  * File-system tells the kernel to invalidate cache for the given node id.
910  */
911 int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid,
912 			     loff_t offset, loff_t len);
913 
914 /**
915  * File-system tells the kernel to invalidate parent attributes and
916  * the dentry matching parent/name.
917  *
918  * If the child_nodeid is non-zero and:
919  *    - matches the inode number for the dentry matching parent/name,
920  *    - is not a mount point
921  *    - is a file or oan empty directory
922  * then the dentry is unhashed (d_delete()).
923  */
924 int fuse_reverse_inval_entry(struct super_block *sb, u64 parent_nodeid,
925 			     u64 child_nodeid, struct qstr *name);
926 
927 int fuse_do_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
928 		 bool isdir);
929 
930 /**
931  * fuse_direct_io() flags
932  */
933 
934 /** If set, it is WRITE; otherwise - READ */
935 #define FUSE_DIO_WRITE (1 << 0)
936 
937 /** CUSE pass fuse_direct_io() a file which f_mapping->host is not from FUSE */
938 #define FUSE_DIO_CUSE  (1 << 1)
939 
940 ssize_t fuse_direct_io(struct fuse_io_priv *io, struct iov_iter *iter,
941 		       loff_t *ppos, int flags);
942 long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
943 		   unsigned int flags);
944 long fuse_ioctl_common(struct file *file, unsigned int cmd,
945 		       unsigned long arg, unsigned int flags);
946 unsigned fuse_file_poll(struct file *file, poll_table *wait);
947 int fuse_dev_release(struct inode *inode, struct file *file);
948 
949 bool fuse_write_update_size(struct inode *inode, loff_t pos);
950 
951 int fuse_flush_times(struct inode *inode, struct fuse_file *ff);
952 int fuse_write_inode(struct inode *inode, struct writeback_control *wbc);
953 
954 int fuse_do_setattr(struct inode *inode, struct iattr *attr,
955 		    struct file *file);
956 
957 void fuse_set_initialized(struct fuse_conn *fc);
958 
959 #endif /* _FS_FUSE_I_H */
960