xref: /openbmc/linux/fs/fuse/fuse_i.h (revision f2a89d3b)
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 	bool blocking;
263 };
264 
265 #define FUSE_IO_PRIV_SYNC(f) \
266 {					\
267 	.refcnt = { ATOMIC_INIT(1) },	\
268 	.async = 0,			\
269 	.file = f,			\
270 }
271 
272 /**
273  * Request flags
274  *
275  * FR_ISREPLY:		set if the request has reply
276  * FR_FORCE:		force sending of the request even if interrupted
277  * FR_BACKGROUND:	request is sent in the background
278  * FR_WAITING:		request is counted as "waiting"
279  * FR_ABORTED:		the request was aborted
280  * FR_INTERRUPTED:	the request has been interrupted
281  * FR_LOCKED:		data is being copied to/from the request
282  * FR_PENDING:		request is not yet in userspace
283  * FR_SENT:		request is in userspace, waiting for an answer
284  * FR_FINISHED:		request is finished
285  * FR_PRIVATE:		request is on private list
286  */
287 enum fuse_req_flag {
288 	FR_ISREPLY,
289 	FR_FORCE,
290 	FR_BACKGROUND,
291 	FR_WAITING,
292 	FR_ABORTED,
293 	FR_INTERRUPTED,
294 	FR_LOCKED,
295 	FR_PENDING,
296 	FR_SENT,
297 	FR_FINISHED,
298 	FR_PRIVATE,
299 };
300 
301 /**
302  * A request to the client
303  *
304  * .waitq.lock protects the following fields:
305  *   - FR_ABORTED
306  *   - FR_LOCKED (may also be modified under fc->lock, tested under both)
307  */
308 struct fuse_req {
309 	/** This can be on either pending processing or io lists in
310 	    fuse_conn */
311 	struct list_head list;
312 
313 	/** Entry on the interrupts list  */
314 	struct list_head intr_entry;
315 
316 	/** refcount */
317 	atomic_t count;
318 
319 	/** Unique ID for the interrupt request */
320 	u64 intr_unique;
321 
322 	/* Request flags, updated with test/set/clear_bit() */
323 	unsigned long flags;
324 
325 	/** The request input */
326 	struct fuse_in in;
327 
328 	/** The request output */
329 	struct fuse_out out;
330 
331 	/** Used to wake up the task waiting for completion of request*/
332 	wait_queue_head_t waitq;
333 
334 	/** Data for asynchronous requests */
335 	union {
336 		struct {
337 			struct fuse_release_in in;
338 			struct inode *inode;
339 		} release;
340 		struct fuse_init_in init_in;
341 		struct fuse_init_out init_out;
342 		struct cuse_init_in cuse_init_in;
343 		struct {
344 			struct fuse_read_in in;
345 			u64 attr_ver;
346 		} read;
347 		struct {
348 			struct fuse_write_in in;
349 			struct fuse_write_out out;
350 			struct fuse_req *next;
351 		} write;
352 		struct fuse_notify_retrieve_in retrieve_in;
353 	} misc;
354 
355 	/** page vector */
356 	struct page **pages;
357 
358 	/** page-descriptor vector */
359 	struct fuse_page_desc *page_descs;
360 
361 	/** size of the 'pages' array */
362 	unsigned max_pages;
363 
364 	/** inline page vector */
365 	struct page *inline_pages[FUSE_REQ_INLINE_PAGES];
366 
367 	/** inline page-descriptor vector */
368 	struct fuse_page_desc inline_page_descs[FUSE_REQ_INLINE_PAGES];
369 
370 	/** number of pages in vector */
371 	unsigned num_pages;
372 
373 	/** File used in the request (or NULL) */
374 	struct fuse_file *ff;
375 
376 	/** Inode used in the request or NULL */
377 	struct inode *inode;
378 
379 	/** AIO control block */
380 	struct fuse_io_priv *io;
381 
382 	/** Link on fi->writepages */
383 	struct list_head writepages_entry;
384 
385 	/** Request completion callback */
386 	void (*end)(struct fuse_conn *, struct fuse_req *);
387 
388 	/** Request is stolen from fuse_file->reserved_req */
389 	struct file *stolen_file;
390 };
391 
392 struct fuse_iqueue {
393 	/** Connection established */
394 	unsigned connected;
395 
396 	/** Readers of the connection are waiting on this */
397 	wait_queue_head_t waitq;
398 
399 	/** The next unique request id */
400 	u64 reqctr;
401 
402 	/** The list of pending requests */
403 	struct list_head pending;
404 
405 	/** Pending interrupts */
406 	struct list_head interrupts;
407 
408 	/** Queue of pending forgets */
409 	struct fuse_forget_link forget_list_head;
410 	struct fuse_forget_link *forget_list_tail;
411 
412 	/** Batching of FORGET requests (positive indicates FORGET batch) */
413 	int forget_batch;
414 
415 	/** O_ASYNC requests */
416 	struct fasync_struct *fasync;
417 };
418 
419 struct fuse_pqueue {
420 	/** Connection established */
421 	unsigned connected;
422 
423 	/** Lock protecting accessess to  members of this structure */
424 	spinlock_t lock;
425 
426 	/** The list of requests being processed */
427 	struct list_head processing;
428 
429 	/** The list of requests under I/O */
430 	struct list_head io;
431 };
432 
433 /**
434  * Fuse device instance
435  */
436 struct fuse_dev {
437 	/** Fuse connection for this device */
438 	struct fuse_conn *fc;
439 
440 	/** Processing queue */
441 	struct fuse_pqueue pq;
442 
443 	/** list entry on fc->devices */
444 	struct list_head entry;
445 };
446 
447 /**
448  * A Fuse connection.
449  *
450  * This structure is created, when the filesystem is mounted, and is
451  * destroyed, when the client device is closed and the filesystem is
452  * unmounted.
453  */
454 struct fuse_conn {
455 	/** Lock protecting accessess to  members of this structure */
456 	spinlock_t lock;
457 
458 	/** Refcount */
459 	atomic_t count;
460 
461 	/** Number of fuse_dev's */
462 	atomic_t dev_count;
463 
464 	struct rcu_head rcu;
465 
466 	/** The user id for this mount */
467 	kuid_t user_id;
468 
469 	/** The group id for this mount */
470 	kgid_t group_id;
471 
472 	/** The fuse mount flags for this mount */
473 	unsigned flags;
474 
475 	/** Maximum read size */
476 	unsigned max_read;
477 
478 	/** Maximum write size */
479 	unsigned max_write;
480 
481 	/** Input queue */
482 	struct fuse_iqueue iq;
483 
484 	/** The next unique kernel file handle */
485 	u64 khctr;
486 
487 	/** rbtree of fuse_files waiting for poll events indexed by ph */
488 	struct rb_root polled_files;
489 
490 	/** Maximum number of outstanding background requests */
491 	unsigned max_background;
492 
493 	/** Number of background requests at which congestion starts */
494 	unsigned congestion_threshold;
495 
496 	/** Number of requests currently in the background */
497 	unsigned num_background;
498 
499 	/** Number of background requests currently queued for userspace */
500 	unsigned active_background;
501 
502 	/** The list of background requests set aside for later queuing */
503 	struct list_head bg_queue;
504 
505 	/** Flag indicating that INIT reply has been received. Allocating
506 	 * any fuse request will be suspended until the flag is set */
507 	int initialized;
508 
509 	/** Flag indicating if connection is blocked.  This will be
510 	    the case before the INIT reply is received, and if there
511 	    are too many outstading backgrounds requests */
512 	int blocked;
513 
514 	/** waitq for blocked connection */
515 	wait_queue_head_t blocked_waitq;
516 
517 	/** waitq for reserved requests */
518 	wait_queue_head_t reserved_req_waitq;
519 
520 	/** Connection established, cleared on umount, connection
521 	    abort and device release */
522 	unsigned connected;
523 
524 	/** Connection failed (version mismatch).  Cannot race with
525 	    setting other bitfields since it is only set once in INIT
526 	    reply, before any other request, and never cleared */
527 	unsigned conn_error:1;
528 
529 	/** Connection successful.  Only set in INIT */
530 	unsigned conn_init:1;
531 
532 	/** Do readpages asynchronously?  Only set in INIT */
533 	unsigned async_read:1;
534 
535 	/** Do not send separate SETATTR request before open(O_TRUNC)  */
536 	unsigned atomic_o_trunc:1;
537 
538 	/** Filesystem supports NFS exporting.  Only set in INIT */
539 	unsigned export_support:1;
540 
541 	/** Set if bdi is valid */
542 	unsigned bdi_initialized:1;
543 
544 	/** write-back cache policy (default is write-through) */
545 	unsigned writeback_cache:1;
546 
547 	/** allow parallel lookups and readdir (default is serialized) */
548 	unsigned parallel_dirops:1;
549 
550 	/*
551 	 * The following bitfields are only for optimization purposes
552 	 * and hence races in setting them will not cause malfunction
553 	 */
554 
555 	/** Is open/release not implemented by fs? */
556 	unsigned no_open:1;
557 
558 	/** Is fsync not implemented by fs? */
559 	unsigned no_fsync:1;
560 
561 	/** Is fsyncdir not implemented by fs? */
562 	unsigned no_fsyncdir:1;
563 
564 	/** Is flush not implemented by fs? */
565 	unsigned no_flush:1;
566 
567 	/** Is setxattr not implemented by fs? */
568 	unsigned no_setxattr:1;
569 
570 	/** Is getxattr not implemented by fs? */
571 	unsigned no_getxattr:1;
572 
573 	/** Is listxattr not implemented by fs? */
574 	unsigned no_listxattr:1;
575 
576 	/** Is removexattr not implemented by fs? */
577 	unsigned no_removexattr:1;
578 
579 	/** Are posix file locking primitives not implemented by fs? */
580 	unsigned no_lock:1;
581 
582 	/** Is access not implemented by fs? */
583 	unsigned no_access:1;
584 
585 	/** Is create not implemented by fs? */
586 	unsigned no_create:1;
587 
588 	/** Is interrupt not implemented by fs? */
589 	unsigned no_interrupt:1;
590 
591 	/** Is bmap not implemented by fs? */
592 	unsigned no_bmap:1;
593 
594 	/** Is poll not implemented by fs? */
595 	unsigned no_poll:1;
596 
597 	/** Do multi-page cached writes */
598 	unsigned big_writes:1;
599 
600 	/** Don't apply umask to creation modes */
601 	unsigned dont_mask:1;
602 
603 	/** Are BSD file locking primitives not implemented by fs? */
604 	unsigned no_flock:1;
605 
606 	/** Is fallocate not implemented by fs? */
607 	unsigned no_fallocate:1;
608 
609 	/** Is rename with flags implemented by fs? */
610 	unsigned no_rename2:1;
611 
612 	/** Use enhanced/automatic page cache invalidation. */
613 	unsigned auto_inval_data:1;
614 
615 	/** Does the filesystem support readdirplus? */
616 	unsigned do_readdirplus:1;
617 
618 	/** Does the filesystem want adaptive readdirplus? */
619 	unsigned readdirplus_auto:1;
620 
621 	/** Does the filesystem support asynchronous direct-IO submission? */
622 	unsigned async_dio:1;
623 
624 	/** Is lseek not implemented by fs? */
625 	unsigned no_lseek:1;
626 
627 	/** The number of requests waiting for completion */
628 	atomic_t num_waiting;
629 
630 	/** Negotiated minor version */
631 	unsigned minor;
632 
633 	/** Backing dev info */
634 	struct backing_dev_info bdi;
635 
636 	/** Entry on the fuse_conn_list */
637 	struct list_head entry;
638 
639 	/** Device ID from super block */
640 	dev_t dev;
641 
642 	/** Dentries in the control filesystem */
643 	struct dentry *ctl_dentry[FUSE_CTL_NUM_DENTRIES];
644 
645 	/** number of dentries used in the above array */
646 	int ctl_ndents;
647 
648 	/** Key for lock owner ID scrambling */
649 	u32 scramble_key[4];
650 
651 	/** Reserved request for the DESTROY message */
652 	struct fuse_req *destroy_req;
653 
654 	/** Version counter for attribute changes */
655 	u64 attr_version;
656 
657 	/** Called on final put */
658 	void (*release)(struct fuse_conn *);
659 
660 	/** Super block for this connection. */
661 	struct super_block *sb;
662 
663 	/** Read/write semaphore to hold when accessing sb. */
664 	struct rw_semaphore killsb;
665 
666 	/** List of device instances belonging to this connection */
667 	struct list_head devices;
668 };
669 
670 static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb)
671 {
672 	return sb->s_fs_info;
673 }
674 
675 static inline struct fuse_conn *get_fuse_conn(struct inode *inode)
676 {
677 	return get_fuse_conn_super(inode->i_sb);
678 }
679 
680 static inline struct fuse_inode *get_fuse_inode(struct inode *inode)
681 {
682 	return container_of(inode, struct fuse_inode, inode);
683 }
684 
685 static inline u64 get_node_id(struct inode *inode)
686 {
687 	return get_fuse_inode(inode)->nodeid;
688 }
689 
690 /** Device operations */
691 extern const struct file_operations fuse_dev_operations;
692 
693 extern const struct dentry_operations fuse_dentry_operations;
694 
695 /**
696  * Inode to nodeid comparison.
697  */
698 int fuse_inode_eq(struct inode *inode, void *_nodeidp);
699 
700 /**
701  * Get a filled in inode
702  */
703 struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
704 			int generation, struct fuse_attr *attr,
705 			u64 attr_valid, u64 attr_version);
706 
707 int fuse_lookup_name(struct super_block *sb, u64 nodeid, const struct qstr *name,
708 		     struct fuse_entry_out *outarg, struct inode **inode);
709 
710 /**
711  * Send FORGET command
712  */
713 void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget,
714 		       u64 nodeid, u64 nlookup);
715 
716 struct fuse_forget_link *fuse_alloc_forget(void);
717 
718 /* Used by READDIRPLUS */
719 void fuse_force_forget(struct file *file, u64 nodeid);
720 
721 /**
722  * Initialize READ or READDIR request
723  */
724 void fuse_read_fill(struct fuse_req *req, struct file *file,
725 		    loff_t pos, size_t count, int opcode);
726 
727 /**
728  * Send OPEN or OPENDIR request
729  */
730 int fuse_open_common(struct inode *inode, struct file *file, bool isdir);
731 
732 struct fuse_file *fuse_file_alloc(struct fuse_conn *fc);
733 struct fuse_file *fuse_file_get(struct fuse_file *ff);
734 void fuse_file_free(struct fuse_file *ff);
735 void fuse_finish_open(struct inode *inode, struct file *file);
736 
737 void fuse_sync_release(struct fuse_file *ff, int flags);
738 
739 /**
740  * Send RELEASE or RELEASEDIR request
741  */
742 void fuse_release_common(struct file *file, int opcode);
743 
744 /**
745  * Send FSYNC or FSYNCDIR request
746  */
747 int fuse_fsync_common(struct file *file, loff_t start, loff_t end,
748 		      int datasync, int isdir);
749 
750 /**
751  * Notify poll wakeup
752  */
753 int fuse_notify_poll_wakeup(struct fuse_conn *fc,
754 			    struct fuse_notify_poll_wakeup_out *outarg);
755 
756 /**
757  * Initialize file operations on a regular file
758  */
759 void fuse_init_file_inode(struct inode *inode);
760 
761 /**
762  * Initialize inode operations on regular files and special files
763  */
764 void fuse_init_common(struct inode *inode);
765 
766 /**
767  * Initialize inode and file operations on a directory
768  */
769 void fuse_init_dir(struct inode *inode);
770 
771 /**
772  * Initialize inode operations on a symlink
773  */
774 void fuse_init_symlink(struct inode *inode);
775 
776 /**
777  * Change attributes of an inode
778  */
779 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
780 			    u64 attr_valid, u64 attr_version);
781 
782 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
783 				   u64 attr_valid);
784 
785 /**
786  * Initialize the client device
787  */
788 int fuse_dev_init(void);
789 
790 /**
791  * Cleanup the client device
792  */
793 void fuse_dev_cleanup(void);
794 
795 int fuse_ctl_init(void);
796 void __exit fuse_ctl_cleanup(void);
797 
798 /**
799  * Allocate a request
800  */
801 struct fuse_req *fuse_request_alloc(unsigned npages);
802 
803 struct fuse_req *fuse_request_alloc_nofs(unsigned npages);
804 
805 /**
806  * Free a request
807  */
808 void fuse_request_free(struct fuse_req *req);
809 
810 /**
811  * Get a request, may fail with -ENOMEM,
812  * caller should specify # elements in req->pages[] explicitly
813  */
814 struct fuse_req *fuse_get_req(struct fuse_conn *fc, unsigned npages);
815 struct fuse_req *fuse_get_req_for_background(struct fuse_conn *fc,
816 					     unsigned npages);
817 
818 /*
819  * Increment reference count on request
820  */
821 void __fuse_get_request(struct fuse_req *req);
822 
823 /**
824  * Gets a requests for a file operation, always succeeds
825  */
826 struct fuse_req *fuse_get_req_nofail_nopages(struct fuse_conn *fc,
827 					     struct file *file);
828 
829 /**
830  * Decrement reference count of a request.  If count goes to zero free
831  * the request.
832  */
833 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req);
834 
835 /**
836  * Send a request (synchronous)
837  */
838 void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req);
839 
840 /**
841  * Simple request sending that does request allocation and freeing
842  */
843 ssize_t fuse_simple_request(struct fuse_conn *fc, struct fuse_args *args);
844 
845 /**
846  * Send a request in the background
847  */
848 void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req);
849 
850 void fuse_request_send_background_locked(struct fuse_conn *fc,
851 					 struct fuse_req *req);
852 
853 /* Abort all requests */
854 void fuse_abort_conn(struct fuse_conn *fc);
855 
856 /**
857  * Invalidate inode attributes
858  */
859 void fuse_invalidate_attr(struct inode *inode);
860 
861 void fuse_invalidate_entry_cache(struct dentry *entry);
862 
863 void fuse_invalidate_atime(struct inode *inode);
864 
865 /**
866  * Acquire reference to fuse_conn
867  */
868 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc);
869 
870 /**
871  * Initialize fuse_conn
872  */
873 void fuse_conn_init(struct fuse_conn *fc);
874 
875 /**
876  * Release reference to fuse_conn
877  */
878 void fuse_conn_put(struct fuse_conn *fc);
879 
880 struct fuse_dev *fuse_dev_alloc(struct fuse_conn *fc);
881 void fuse_dev_free(struct fuse_dev *fud);
882 
883 /**
884  * Add connection to control filesystem
885  */
886 int fuse_ctl_add_conn(struct fuse_conn *fc);
887 
888 /**
889  * Remove connection from control filesystem
890  */
891 void fuse_ctl_remove_conn(struct fuse_conn *fc);
892 
893 /**
894  * Is file type valid?
895  */
896 int fuse_valid_type(int m);
897 
898 /**
899  * Is current process allowed to perform filesystem operation?
900  */
901 int fuse_allow_current_process(struct fuse_conn *fc);
902 
903 u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id);
904 
905 int fuse_update_attributes(struct inode *inode, struct kstat *stat,
906 			   struct file *file, bool *refreshed);
907 
908 void fuse_flush_writepages(struct inode *inode);
909 
910 void fuse_set_nowrite(struct inode *inode);
911 void fuse_release_nowrite(struct inode *inode);
912 
913 u64 fuse_get_attr_version(struct fuse_conn *fc);
914 
915 /**
916  * File-system tells the kernel to invalidate cache for the given node id.
917  */
918 int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid,
919 			     loff_t offset, loff_t len);
920 
921 /**
922  * File-system tells the kernel to invalidate parent attributes and
923  * the dentry matching parent/name.
924  *
925  * If the child_nodeid is non-zero and:
926  *    - matches the inode number for the dentry matching parent/name,
927  *    - is not a mount point
928  *    - is a file or oan empty directory
929  * then the dentry is unhashed (d_delete()).
930  */
931 int fuse_reverse_inval_entry(struct super_block *sb, u64 parent_nodeid,
932 			     u64 child_nodeid, struct qstr *name);
933 
934 int fuse_do_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
935 		 bool isdir);
936 
937 /**
938  * fuse_direct_io() flags
939  */
940 
941 /** If set, it is WRITE; otherwise - READ */
942 #define FUSE_DIO_WRITE (1 << 0)
943 
944 /** CUSE pass fuse_direct_io() a file which f_mapping->host is not from FUSE */
945 #define FUSE_DIO_CUSE  (1 << 1)
946 
947 ssize_t fuse_direct_io(struct fuse_io_priv *io, struct iov_iter *iter,
948 		       loff_t *ppos, int flags);
949 long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
950 		   unsigned int flags);
951 long fuse_ioctl_common(struct file *file, unsigned int cmd,
952 		       unsigned long arg, unsigned int flags);
953 unsigned fuse_file_poll(struct file *file, poll_table *wait);
954 int fuse_dev_release(struct inode *inode, struct file *file);
955 
956 bool fuse_write_update_size(struct inode *inode, loff_t pos);
957 
958 int fuse_flush_times(struct inode *inode, struct fuse_file *ff);
959 int fuse_write_inode(struct inode *inode, struct writeback_control *wbc);
960 
961 int fuse_do_setattr(struct inode *inode, struct iattr *attr,
962 		    struct file *file);
963 
964 void fuse_set_initialized(struct fuse_conn *fc);
965 
966 void fuse_unlock_inode(struct inode *inode);
967 void fuse_lock_inode(struct inode *inode);
968 
969 #endif /* _FS_FUSE_I_H */
970