xref: /openbmc/linux/fs/fuse/fuse_i.h (revision 23c2b932)
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 	/** Lock for serializing lookup and readdir for back compatibility*/
115 	struct mutex mutex;
116 };
117 
118 /** FUSE inode state bits */
119 enum {
120 	/** Advise readdirplus  */
121 	FUSE_I_ADVISE_RDPLUS,
122 	/** Initialized with readdirplus */
123 	FUSE_I_INIT_RDPLUS,
124 	/** An operation changing file size is in progress  */
125 	FUSE_I_SIZE_UNSTABLE,
126 };
127 
128 struct fuse_conn;
129 
130 /** FUSE specific file data */
131 struct fuse_file {
132 	/** Fuse connection for this file */
133 	struct fuse_conn *fc;
134 
135 	/** Request reserved for flush and release */
136 	struct fuse_req *reserved_req;
137 
138 	/** Kernel file handle guaranteed to be unique */
139 	u64 kh;
140 
141 	/** File handle used by userspace */
142 	u64 fh;
143 
144 	/** Node id of this file */
145 	u64 nodeid;
146 
147 	/** Refcount */
148 	atomic_t count;
149 
150 	/** FOPEN_* flags returned by open */
151 	u32 open_flags;
152 
153 	/** Entry on inode's write_files list */
154 	struct list_head write_entry;
155 
156 	/** RB node to be linked on fuse_conn->polled_files */
157 	struct rb_node polled_node;
158 
159 	/** Wait queue head for poll */
160 	wait_queue_head_t poll_wait;
161 
162 	/** Has flock been performed on this file? */
163 	bool flock:1;
164 };
165 
166 /** One input argument of a request */
167 struct fuse_in_arg {
168 	unsigned size;
169 	const void *value;
170 };
171 
172 /** The request input */
173 struct fuse_in {
174 	/** The request header */
175 	struct fuse_in_header h;
176 
177 	/** True if the data for the last argument is in req->pages */
178 	unsigned argpages:1;
179 
180 	/** Number of arguments */
181 	unsigned numargs;
182 
183 	/** Array of arguments */
184 	struct fuse_in_arg args[3];
185 };
186 
187 /** One output argument of a request */
188 struct fuse_arg {
189 	unsigned size;
190 	void *value;
191 };
192 
193 /** The request output */
194 struct fuse_out {
195 	/** Header returned from userspace */
196 	struct fuse_out_header h;
197 
198 	/*
199 	 * The following bitfields are not changed during the request
200 	 * processing
201 	 */
202 
203 	/** Last argument is variable length (can be shorter than
204 	    arg->size) */
205 	unsigned argvar:1;
206 
207 	/** Last argument is a list of pages to copy data to */
208 	unsigned argpages:1;
209 
210 	/** Zero partially or not copied pages */
211 	unsigned page_zeroing:1;
212 
213 	/** Pages may be replaced with new ones */
214 	unsigned page_replace:1;
215 
216 	/** Number or arguments */
217 	unsigned numargs;
218 
219 	/** Array of arguments */
220 	struct fuse_arg args[2];
221 };
222 
223 /** FUSE page descriptor */
224 struct fuse_page_desc {
225 	unsigned int length;
226 	unsigned int offset;
227 };
228 
229 struct fuse_args {
230 	struct {
231 		struct {
232 			uint32_t opcode;
233 			uint64_t nodeid;
234 		} h;
235 		unsigned numargs;
236 		struct fuse_in_arg args[3];
237 
238 	} in;
239 	struct {
240 		unsigned argvar:1;
241 		unsigned numargs;
242 		struct fuse_arg args[2];
243 	} out;
244 };
245 
246 #define FUSE_ARGS(args) struct fuse_args args = {}
247 
248 /** The request IO state (for asynchronous processing) */
249 struct fuse_io_priv {
250 	struct kref refcnt;
251 	int async;
252 	spinlock_t lock;
253 	unsigned reqs;
254 	ssize_t bytes;
255 	size_t size;
256 	__u64 offset;
257 	bool write;
258 	int err;
259 	struct kiocb *iocb;
260 	struct file *file;
261 	struct completion *done;
262 };
263 
264 #define FUSE_IO_PRIV_SYNC(f) \
265 {					\
266 	.refcnt = { ATOMIC_INIT(1) },	\
267 	.async = 0,			\
268 	.file = f,			\
269 }
270 
271 /**
272  * Request flags
273  *
274  * FR_ISREPLY:		set if the request has reply
275  * FR_FORCE:		force sending of the request even if interrupted
276  * FR_BACKGROUND:	request is sent in the background
277  * FR_WAITING:		request is counted as "waiting"
278  * FR_ABORTED:		the request was aborted
279  * FR_INTERRUPTED:	the request has been interrupted
280  * FR_LOCKED:		data is being copied to/from the request
281  * FR_PENDING:		request is not yet in userspace
282  * FR_SENT:		request is in userspace, waiting for an answer
283  * FR_FINISHED:		request is finished
284  * FR_PRIVATE:		request is on private list
285  */
286 enum fuse_req_flag {
287 	FR_ISREPLY,
288 	FR_FORCE,
289 	FR_BACKGROUND,
290 	FR_WAITING,
291 	FR_ABORTED,
292 	FR_INTERRUPTED,
293 	FR_LOCKED,
294 	FR_PENDING,
295 	FR_SENT,
296 	FR_FINISHED,
297 	FR_PRIVATE,
298 };
299 
300 /**
301  * A request to the client
302  *
303  * .waitq.lock protects the following fields:
304  *   - FR_ABORTED
305  *   - FR_LOCKED (may also be modified under fc->lock, tested under both)
306  */
307 struct fuse_req {
308 	/** This can be on either pending processing or io lists in
309 	    fuse_conn */
310 	struct list_head list;
311 
312 	/** Entry on the interrupts list  */
313 	struct list_head intr_entry;
314 
315 	/** refcount */
316 	atomic_t count;
317 
318 	/** Unique ID for the interrupt request */
319 	u64 intr_unique;
320 
321 	/* Request flags, updated with test/set/clear_bit() */
322 	unsigned long flags;
323 
324 	/** The request input */
325 	struct fuse_in in;
326 
327 	/** The request output */
328 	struct fuse_out out;
329 
330 	/** Used to wake up the task waiting for completion of request*/
331 	wait_queue_head_t waitq;
332 
333 	/** Data for asynchronous requests */
334 	union {
335 		struct {
336 			struct fuse_release_in in;
337 			struct inode *inode;
338 		} release;
339 		struct fuse_init_in init_in;
340 		struct fuse_init_out init_out;
341 		struct cuse_init_in cuse_init_in;
342 		struct {
343 			struct fuse_read_in in;
344 			u64 attr_ver;
345 		} read;
346 		struct {
347 			struct fuse_write_in in;
348 			struct fuse_write_out out;
349 			struct fuse_req *next;
350 		} write;
351 		struct fuse_notify_retrieve_in retrieve_in;
352 	} misc;
353 
354 	/** page vector */
355 	struct page **pages;
356 
357 	/** page-descriptor vector */
358 	struct fuse_page_desc *page_descs;
359 
360 	/** size of the 'pages' array */
361 	unsigned max_pages;
362 
363 	/** inline page vector */
364 	struct page *inline_pages[FUSE_REQ_INLINE_PAGES];
365 
366 	/** inline page-descriptor vector */
367 	struct fuse_page_desc inline_page_descs[FUSE_REQ_INLINE_PAGES];
368 
369 	/** number of pages in vector */
370 	unsigned num_pages;
371 
372 	/** File used in the request (or NULL) */
373 	struct fuse_file *ff;
374 
375 	/** Inode used in the request or NULL */
376 	struct inode *inode;
377 
378 	/** AIO control block */
379 	struct fuse_io_priv *io;
380 
381 	/** Link on fi->writepages */
382 	struct list_head writepages_entry;
383 
384 	/** Request completion callback */
385 	void (*end)(struct fuse_conn *, struct fuse_req *);
386 
387 	/** Request is stolen from fuse_file->reserved_req */
388 	struct file *stolen_file;
389 };
390 
391 struct fuse_iqueue {
392 	/** Connection established */
393 	unsigned connected;
394 
395 	/** Readers of the connection are waiting on this */
396 	wait_queue_head_t waitq;
397 
398 	/** The next unique request id */
399 	u64 reqctr;
400 
401 	/** The list of pending requests */
402 	struct list_head pending;
403 
404 	/** Pending interrupts */
405 	struct list_head interrupts;
406 
407 	/** Queue of pending forgets */
408 	struct fuse_forget_link forget_list_head;
409 	struct fuse_forget_link *forget_list_tail;
410 
411 	/** Batching of FORGET requests (positive indicates FORGET batch) */
412 	int forget_batch;
413 
414 	/** O_ASYNC requests */
415 	struct fasync_struct *fasync;
416 };
417 
418 struct fuse_pqueue {
419 	/** Connection established */
420 	unsigned connected;
421 
422 	/** Lock protecting accessess to  members of this structure */
423 	spinlock_t lock;
424 
425 	/** The list of requests being processed */
426 	struct list_head processing;
427 
428 	/** The list of requests under I/O */
429 	struct list_head io;
430 };
431 
432 /**
433  * Fuse device instance
434  */
435 struct fuse_dev {
436 	/** Fuse connection for this device */
437 	struct fuse_conn *fc;
438 
439 	/** Processing queue */
440 	struct fuse_pqueue pq;
441 
442 	/** list entry on fc->devices */
443 	struct list_head entry;
444 };
445 
446 /**
447  * A Fuse connection.
448  *
449  * This structure is created, when the filesystem is mounted, and is
450  * destroyed, when the client device is closed and the filesystem is
451  * unmounted.
452  */
453 struct fuse_conn {
454 	/** Lock protecting accessess to  members of this structure */
455 	spinlock_t lock;
456 
457 	/** Refcount */
458 	atomic_t count;
459 
460 	/** Number of fuse_dev's */
461 	atomic_t dev_count;
462 
463 	struct rcu_head rcu;
464 
465 	/** The user id for this mount */
466 	kuid_t user_id;
467 
468 	/** The group id for this mount */
469 	kgid_t group_id;
470 
471 	/** The fuse mount flags for this mount */
472 	unsigned flags;
473 
474 	/** Maximum read size */
475 	unsigned max_read;
476 
477 	/** Maximum write size */
478 	unsigned max_write;
479 
480 	/** Input queue */
481 	struct fuse_iqueue iq;
482 
483 	/** The next unique kernel file handle */
484 	u64 khctr;
485 
486 	/** rbtree of fuse_files waiting for poll events indexed by ph */
487 	struct rb_root polled_files;
488 
489 	/** Maximum number of outstanding background requests */
490 	unsigned max_background;
491 
492 	/** Number of background requests at which congestion starts */
493 	unsigned congestion_threshold;
494 
495 	/** Number of requests currently in the background */
496 	unsigned num_background;
497 
498 	/** Number of background requests currently queued for userspace */
499 	unsigned active_background;
500 
501 	/** The list of background requests set aside for later queuing */
502 	struct list_head bg_queue;
503 
504 	/** Flag indicating that INIT reply has been received. Allocating
505 	 * any fuse request will be suspended until the flag is set */
506 	int initialized;
507 
508 	/** Flag indicating if connection is blocked.  This will be
509 	    the case before the INIT reply is received, and if there
510 	    are too many outstading backgrounds requests */
511 	int blocked;
512 
513 	/** waitq for blocked connection */
514 	wait_queue_head_t blocked_waitq;
515 
516 	/** waitq for reserved requests */
517 	wait_queue_head_t reserved_req_waitq;
518 
519 	/** Connection established, cleared on umount, connection
520 	    abort and device release */
521 	unsigned connected;
522 
523 	/** Connection failed (version mismatch).  Cannot race with
524 	    setting other bitfields since it is only set once in INIT
525 	    reply, before any other request, and never cleared */
526 	unsigned conn_error:1;
527 
528 	/** Connection successful.  Only set in INIT */
529 	unsigned conn_init:1;
530 
531 	/** Do readpages asynchronously?  Only set in INIT */
532 	unsigned async_read:1;
533 
534 	/** Do not send separate SETATTR request before open(O_TRUNC)  */
535 	unsigned atomic_o_trunc:1;
536 
537 	/** Filesystem supports NFS exporting.  Only set in INIT */
538 	unsigned export_support:1;
539 
540 	/** Set if bdi is valid */
541 	unsigned bdi_initialized:1;
542 
543 	/** write-back cache policy (default is write-through) */
544 	unsigned writeback_cache:1;
545 
546 	/** allow parallel lookups and readdir (default is serialized) */
547 	unsigned parallel_dirops:1;
548 
549 	/*
550 	 * The following bitfields are only for optimization purposes
551 	 * and hence races in setting them will not cause malfunction
552 	 */
553 
554 	/** Is open/release not implemented by fs? */
555 	unsigned no_open:1;
556 
557 	/** Is fsync not implemented by fs? */
558 	unsigned no_fsync:1;
559 
560 	/** Is fsyncdir not implemented by fs? */
561 	unsigned no_fsyncdir:1;
562 
563 	/** Is flush not implemented by fs? */
564 	unsigned no_flush:1;
565 
566 	/** Is setxattr not implemented by fs? */
567 	unsigned no_setxattr:1;
568 
569 	/** Is getxattr not implemented by fs? */
570 	unsigned no_getxattr:1;
571 
572 	/** Is listxattr not implemented by fs? */
573 	unsigned no_listxattr:1;
574 
575 	/** Is removexattr not implemented by fs? */
576 	unsigned no_removexattr:1;
577 
578 	/** Are posix file locking primitives not implemented by fs? */
579 	unsigned no_lock:1;
580 
581 	/** Is access not implemented by fs? */
582 	unsigned no_access:1;
583 
584 	/** Is create not implemented by fs? */
585 	unsigned no_create:1;
586 
587 	/** Is interrupt not implemented by fs? */
588 	unsigned no_interrupt:1;
589 
590 	/** Is bmap not implemented by fs? */
591 	unsigned no_bmap:1;
592 
593 	/** Is poll not implemented by fs? */
594 	unsigned no_poll:1;
595 
596 	/** Do multi-page cached writes */
597 	unsigned big_writes:1;
598 
599 	/** Don't apply umask to creation modes */
600 	unsigned dont_mask:1;
601 
602 	/** Are BSD file locking primitives not implemented by fs? */
603 	unsigned no_flock:1;
604 
605 	/** Is fallocate not implemented by fs? */
606 	unsigned no_fallocate:1;
607 
608 	/** Is rename with flags implemented by fs? */
609 	unsigned no_rename2:1;
610 
611 	/** Use enhanced/automatic page cache invalidation. */
612 	unsigned auto_inval_data:1;
613 
614 	/** Does the filesystem support readdirplus? */
615 	unsigned do_readdirplus:1;
616 
617 	/** Does the filesystem want adaptive readdirplus? */
618 	unsigned readdirplus_auto:1;
619 
620 	/** Does the filesystem support asynchronous direct-IO submission? */
621 	unsigned async_dio:1;
622 
623 	/** Is lseek not implemented by fs? */
624 	unsigned no_lseek:1;
625 
626 	/** The number of requests waiting for completion */
627 	atomic_t num_waiting;
628 
629 	/** Negotiated minor version */
630 	unsigned minor;
631 
632 	/** Backing dev info */
633 	struct backing_dev_info bdi;
634 
635 	/** Entry on the fuse_conn_list */
636 	struct list_head entry;
637 
638 	/** Device ID from super block */
639 	dev_t dev;
640 
641 	/** Dentries in the control filesystem */
642 	struct dentry *ctl_dentry[FUSE_CTL_NUM_DENTRIES];
643 
644 	/** number of dentries used in the above array */
645 	int ctl_ndents;
646 
647 	/** Key for lock owner ID scrambling */
648 	u32 scramble_key[4];
649 
650 	/** Reserved request for the DESTROY message */
651 	struct fuse_req *destroy_req;
652 
653 	/** Version counter for attribute changes */
654 	u64 attr_version;
655 
656 	/** Called on final put */
657 	void (*release)(struct fuse_conn *);
658 
659 	/** Super block for this connection. */
660 	struct super_block *sb;
661 
662 	/** Read/write semaphore to hold when accessing sb. */
663 	struct rw_semaphore killsb;
664 
665 	/** List of device instances belonging to this connection */
666 	struct list_head devices;
667 };
668 
669 static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb)
670 {
671 	return sb->s_fs_info;
672 }
673 
674 static inline struct fuse_conn *get_fuse_conn(struct inode *inode)
675 {
676 	return get_fuse_conn_super(inode->i_sb);
677 }
678 
679 static inline struct fuse_inode *get_fuse_inode(struct inode *inode)
680 {
681 	return container_of(inode, struct fuse_inode, inode);
682 }
683 
684 static inline u64 get_node_id(struct inode *inode)
685 {
686 	return get_fuse_inode(inode)->nodeid;
687 }
688 
689 /** Device operations */
690 extern const struct file_operations fuse_dev_operations;
691 
692 extern const struct dentry_operations fuse_dentry_operations;
693 
694 /**
695  * Inode to nodeid comparison.
696  */
697 int fuse_inode_eq(struct inode *inode, void *_nodeidp);
698 
699 /**
700  * Get a filled in inode
701  */
702 struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
703 			int generation, struct fuse_attr *attr,
704 			u64 attr_valid, u64 attr_version);
705 
706 int fuse_lookup_name(struct super_block *sb, u64 nodeid, struct qstr *name,
707 		     struct fuse_entry_out *outarg, struct inode **inode);
708 
709 /**
710  * Send FORGET command
711  */
712 void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget,
713 		       u64 nodeid, u64 nlookup);
714 
715 struct fuse_forget_link *fuse_alloc_forget(void);
716 
717 /* Used by READDIRPLUS */
718 void fuse_force_forget(struct file *file, u64 nodeid);
719 
720 /**
721  * Initialize READ or READDIR request
722  */
723 void fuse_read_fill(struct fuse_req *req, struct file *file,
724 		    loff_t pos, size_t count, int opcode);
725 
726 /**
727  * Send OPEN or OPENDIR request
728  */
729 int fuse_open_common(struct inode *inode, struct file *file, bool isdir);
730 
731 struct fuse_file *fuse_file_alloc(struct fuse_conn *fc);
732 struct fuse_file *fuse_file_get(struct fuse_file *ff);
733 void fuse_file_free(struct fuse_file *ff);
734 void fuse_finish_open(struct inode *inode, struct file *file);
735 
736 void fuse_sync_release(struct fuse_file *ff, int flags);
737 
738 /**
739  * Send RELEASE or RELEASEDIR request
740  */
741 void fuse_release_common(struct file *file, int opcode);
742 
743 /**
744  * Send FSYNC or FSYNCDIR request
745  */
746 int fuse_fsync_common(struct file *file, loff_t start, loff_t end,
747 		      int datasync, int isdir);
748 
749 /**
750  * Notify poll wakeup
751  */
752 int fuse_notify_poll_wakeup(struct fuse_conn *fc,
753 			    struct fuse_notify_poll_wakeup_out *outarg);
754 
755 /**
756  * Initialize file operations on a regular file
757  */
758 void fuse_init_file_inode(struct inode *inode);
759 
760 /**
761  * Initialize inode operations on regular files and special files
762  */
763 void fuse_init_common(struct inode *inode);
764 
765 /**
766  * Initialize inode and file operations on a directory
767  */
768 void fuse_init_dir(struct inode *inode);
769 
770 /**
771  * Initialize inode operations on a symlink
772  */
773 void fuse_init_symlink(struct inode *inode);
774 
775 /**
776  * Change attributes of an inode
777  */
778 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
779 			    u64 attr_valid, u64 attr_version);
780 
781 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
782 				   u64 attr_valid);
783 
784 /**
785  * Initialize the client device
786  */
787 int fuse_dev_init(void);
788 
789 /**
790  * Cleanup the client device
791  */
792 void fuse_dev_cleanup(void);
793 
794 int fuse_ctl_init(void);
795 void __exit fuse_ctl_cleanup(void);
796 
797 /**
798  * Allocate a request
799  */
800 struct fuse_req *fuse_request_alloc(unsigned npages);
801 
802 struct fuse_req *fuse_request_alloc_nofs(unsigned npages);
803 
804 /**
805  * Free a request
806  */
807 void fuse_request_free(struct fuse_req *req);
808 
809 /**
810  * Get a request, may fail with -ENOMEM,
811  * caller should specify # elements in req->pages[] explicitly
812  */
813 struct fuse_req *fuse_get_req(struct fuse_conn *fc, unsigned npages);
814 struct fuse_req *fuse_get_req_for_background(struct fuse_conn *fc,
815 					     unsigned npages);
816 
817 /*
818  * Increment reference count on request
819  */
820 void __fuse_get_request(struct fuse_req *req);
821 
822 /**
823  * Gets a requests for a file operation, always succeeds
824  */
825 struct fuse_req *fuse_get_req_nofail_nopages(struct fuse_conn *fc,
826 					     struct file *file);
827 
828 /**
829  * Decrement reference count of a request.  If count goes to zero free
830  * the request.
831  */
832 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req);
833 
834 /**
835  * Send a request (synchronous)
836  */
837 void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req);
838 
839 /**
840  * Simple request sending that does request allocation and freeing
841  */
842 ssize_t fuse_simple_request(struct fuse_conn *fc, struct fuse_args *args);
843 
844 /**
845  * Send a request in the background
846  */
847 void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req);
848 
849 void fuse_request_send_background_locked(struct fuse_conn *fc,
850 					 struct fuse_req *req);
851 
852 /* Abort all requests */
853 void fuse_abort_conn(struct fuse_conn *fc);
854 
855 /**
856  * Invalidate inode attributes
857  */
858 void fuse_invalidate_attr(struct inode *inode);
859 
860 void fuse_invalidate_entry_cache(struct dentry *entry);
861 
862 void fuse_invalidate_atime(struct inode *inode);
863 
864 /**
865  * Acquire reference to fuse_conn
866  */
867 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc);
868 
869 /**
870  * Initialize fuse_conn
871  */
872 void fuse_conn_init(struct fuse_conn *fc);
873 
874 /**
875  * Release reference to fuse_conn
876  */
877 void fuse_conn_put(struct fuse_conn *fc);
878 
879 struct fuse_dev *fuse_dev_alloc(struct fuse_conn *fc);
880 void fuse_dev_free(struct fuse_dev *fud);
881 
882 /**
883  * Add connection to control filesystem
884  */
885 int fuse_ctl_add_conn(struct fuse_conn *fc);
886 
887 /**
888  * Remove connection from control filesystem
889  */
890 void fuse_ctl_remove_conn(struct fuse_conn *fc);
891 
892 /**
893  * Is file type valid?
894  */
895 int fuse_valid_type(int m);
896 
897 /**
898  * Is current process allowed to perform filesystem operation?
899  */
900 int fuse_allow_current_process(struct fuse_conn *fc);
901 
902 u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id);
903 
904 int fuse_update_attributes(struct inode *inode, struct kstat *stat,
905 			   struct file *file, bool *refreshed);
906 
907 void fuse_flush_writepages(struct inode *inode);
908 
909 void fuse_set_nowrite(struct inode *inode);
910 void fuse_release_nowrite(struct inode *inode);
911 
912 u64 fuse_get_attr_version(struct fuse_conn *fc);
913 
914 /**
915  * File-system tells the kernel to invalidate cache for the given node id.
916  */
917 int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid,
918 			     loff_t offset, loff_t len);
919 
920 /**
921  * File-system tells the kernel to invalidate parent attributes and
922  * the dentry matching parent/name.
923  *
924  * If the child_nodeid is non-zero and:
925  *    - matches the inode number for the dentry matching parent/name,
926  *    - is not a mount point
927  *    - is a file or oan empty directory
928  * then the dentry is unhashed (d_delete()).
929  */
930 int fuse_reverse_inval_entry(struct super_block *sb, u64 parent_nodeid,
931 			     u64 child_nodeid, struct qstr *name);
932 
933 int fuse_do_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
934 		 bool isdir);
935 
936 /**
937  * fuse_direct_io() flags
938  */
939 
940 /** If set, it is WRITE; otherwise - READ */
941 #define FUSE_DIO_WRITE (1 << 0)
942 
943 /** CUSE pass fuse_direct_io() a file which f_mapping->host is not from FUSE */
944 #define FUSE_DIO_CUSE  (1 << 1)
945 
946 ssize_t fuse_direct_io(struct fuse_io_priv *io, struct iov_iter *iter,
947 		       loff_t *ppos, int flags);
948 long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
949 		   unsigned int flags);
950 long fuse_ioctl_common(struct file *file, unsigned int cmd,
951 		       unsigned long arg, unsigned int flags);
952 unsigned fuse_file_poll(struct file *file, poll_table *wait);
953 int fuse_dev_release(struct inode *inode, struct file *file);
954 
955 bool fuse_write_update_size(struct inode *inode, loff_t pos);
956 
957 int fuse_flush_times(struct inode *inode, struct fuse_file *ff);
958 int fuse_write_inode(struct inode *inode, struct writeback_control *wbc);
959 
960 int fuse_do_setattr(struct inode *inode, struct iattr *attr,
961 		    struct file *file);
962 
963 void fuse_set_initialized(struct fuse_conn *fc);
964 
965 void fuse_unlock_inode(struct inode *inode);
966 void fuse_lock_inode(struct inode *inode);
967 
968 #endif /* _FS_FUSE_I_H */
969