xref: /linux/fs/fuse/fuse_i.h (revision 4949009eb8d40a441dcddcd96e101e77d31cf1b2)
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 
26 /** Max number of pages that can be used in a single read request */
27 #define FUSE_MAX_PAGES_PER_REQ 32
28 
29 /** Bias for fi->writectr, meaning new writepages must not be sent */
30 #define FUSE_NOWRITE INT_MIN
31 
32 /** It could be as large as PATH_MAX, but would that have any uses? */
33 #define FUSE_NAME_MAX 1024
34 
35 /** Number of dentries for each connection in the control filesystem */
36 #define FUSE_CTL_NUM_DENTRIES 5
37 
38 /** If the FUSE_DEFAULT_PERMISSIONS flag is given, the filesystem
39     module will check permissions based on the file mode.  Otherwise no
40     permission checking is done in the kernel */
41 #define FUSE_DEFAULT_PERMISSIONS (1 << 0)
42 
43 /** If the FUSE_ALLOW_OTHER flag is given, then not only the user
44     doing the mount will be allowed to access the filesystem */
45 #define FUSE_ALLOW_OTHER         (1 << 1)
46 
47 /** Number of page pointers embedded in fuse_req */
48 #define FUSE_REQ_INLINE_PAGES 1
49 
50 /** List of active connections */
51 extern struct list_head fuse_conn_list;
52 
53 /** Global mutex protecting fuse_conn_list and the control filesystem */
54 extern struct mutex fuse_mutex;
55 
56 /** Module parameters */
57 extern unsigned max_user_bgreq;
58 extern unsigned max_user_congthresh;
59 
60 /* One forget request */
61 struct fuse_forget_link {
62 	struct fuse_forget_one forget_one;
63 	struct fuse_forget_link *next;
64 };
65 
66 /** FUSE inode */
67 struct fuse_inode {
68 	/** Inode data */
69 	struct inode inode;
70 
71 	/** Unique ID, which identifies the inode between userspace
72 	 * and kernel */
73 	u64 nodeid;
74 
75 	/** Number of lookups on this inode */
76 	u64 nlookup;
77 
78 	/** The request used for sending the FORGET message */
79 	struct fuse_forget_link *forget;
80 
81 	/** Time in jiffies until the file attributes are valid */
82 	u64 i_time;
83 
84 	/** The sticky bit in inode->i_mode may have been removed, so
85 	    preserve the original mode */
86 	umode_t orig_i_mode;
87 
88 	/** 64 bit inode number */
89 	u64 orig_ino;
90 
91 	/** Version of last attribute change */
92 	u64 attr_version;
93 
94 	/** Files usable in writepage.  Protected by fc->lock */
95 	struct list_head write_files;
96 
97 	/** Writepages pending on truncate or fsync */
98 	struct list_head queued_writes;
99 
100 	/** Number of sent writes, a negative bias (FUSE_NOWRITE)
101 	 * means more writes are blocked */
102 	int writectr;
103 
104 	/** Waitq for writepage completion */
105 	wait_queue_head_t page_waitq;
106 
107 	/** List of writepage requestst (pending or sent) */
108 	struct list_head writepages;
109 
110 	/** Miscellaneous bits describing inode state */
111 	unsigned long state;
112 };
113 
114 /** FUSE inode state bits */
115 enum {
116 	/** Advise readdirplus  */
117 	FUSE_I_ADVISE_RDPLUS,
118 	/** Initialized with readdirplus */
119 	FUSE_I_INIT_RDPLUS,
120 	/** An operation changing file size is in progress  */
121 	FUSE_I_SIZE_UNSTABLE,
122 };
123 
124 struct fuse_conn;
125 
126 /** FUSE specific file data */
127 struct fuse_file {
128 	/** Fuse connection for this file */
129 	struct fuse_conn *fc;
130 
131 	/** Request reserved for flush and release */
132 	struct fuse_req *reserved_req;
133 
134 	/** Kernel file handle guaranteed to be unique */
135 	u64 kh;
136 
137 	/** File handle used by userspace */
138 	u64 fh;
139 
140 	/** Node id of this file */
141 	u64 nodeid;
142 
143 	/** Refcount */
144 	atomic_t count;
145 
146 	/** FOPEN_* flags returned by open */
147 	u32 open_flags;
148 
149 	/** Entry on inode's write_files list */
150 	struct list_head write_entry;
151 
152 	/** RB node to be linked on fuse_conn->polled_files */
153 	struct rb_node polled_node;
154 
155 	/** Wait queue head for poll */
156 	wait_queue_head_t poll_wait;
157 
158 	/** Has flock been performed on this file? */
159 	bool flock:1;
160 };
161 
162 /** One input argument of a request */
163 struct fuse_in_arg {
164 	unsigned size;
165 	const void *value;
166 };
167 
168 /** The request input */
169 struct fuse_in {
170 	/** The request header */
171 	struct fuse_in_header h;
172 
173 	/** True if the data for the last argument is in req->pages */
174 	unsigned argpages:1;
175 
176 	/** Number of arguments */
177 	unsigned numargs;
178 
179 	/** Array of arguments */
180 	struct fuse_in_arg args[3];
181 };
182 
183 /** One output argument of a request */
184 struct fuse_arg {
185 	unsigned size;
186 	void *value;
187 };
188 
189 /** The request output */
190 struct fuse_out {
191 	/** Header returned from userspace */
192 	struct fuse_out_header h;
193 
194 	/*
195 	 * The following bitfields are not changed during the request
196 	 * processing
197 	 */
198 
199 	/** Last argument is variable length (can be shorter than
200 	    arg->size) */
201 	unsigned argvar:1;
202 
203 	/** Last argument is a list of pages to copy data to */
204 	unsigned argpages:1;
205 
206 	/** Zero partially or not copied pages */
207 	unsigned page_zeroing:1;
208 
209 	/** Pages may be replaced with new ones */
210 	unsigned page_replace:1;
211 
212 	/** Number or arguments */
213 	unsigned numargs;
214 
215 	/** Array of arguments */
216 	struct fuse_arg args[2];
217 };
218 
219 /** FUSE page descriptor */
220 struct fuse_page_desc {
221 	unsigned int length;
222 	unsigned int offset;
223 };
224 
225 struct fuse_args {
226 	struct {
227 		struct {
228 			uint32_t opcode;
229 			uint64_t nodeid;
230 		} h;
231 		unsigned numargs;
232 		struct fuse_in_arg args[3];
233 
234 	} in;
235 	struct {
236 		unsigned argvar:1;
237 		unsigned numargs;
238 		struct fuse_arg args[2];
239 	} out;
240 };
241 
242 #define FUSE_ARGS(args) struct fuse_args args = {}
243 
244 /** The request state */
245 enum fuse_req_state {
246 	FUSE_REQ_INIT = 0,
247 	FUSE_REQ_PENDING,
248 	FUSE_REQ_READING,
249 	FUSE_REQ_SENT,
250 	FUSE_REQ_WRITING,
251 	FUSE_REQ_FINISHED
252 };
253 
254 /** The request IO state (for asynchronous processing) */
255 struct fuse_io_priv {
256 	int async;
257 	spinlock_t lock;
258 	unsigned reqs;
259 	ssize_t bytes;
260 	size_t size;
261 	__u64 offset;
262 	bool write;
263 	int err;
264 	struct kiocb *iocb;
265 	struct file *file;
266 };
267 
268 /**
269  * A request to the client
270  */
271 struct fuse_req {
272 	/** This can be on either pending processing or io lists in
273 	    fuse_conn */
274 	struct list_head list;
275 
276 	/** Entry on the interrupts list  */
277 	struct list_head intr_entry;
278 
279 	/** refcount */
280 	atomic_t count;
281 
282 	/** Unique ID for the interrupt request */
283 	u64 intr_unique;
284 
285 	/*
286 	 * The following bitfields are either set once before the
287 	 * request is queued or setting/clearing them is protected by
288 	 * fuse_conn->lock
289 	 */
290 
291 	/** True if the request has reply */
292 	unsigned isreply:1;
293 
294 	/** Force sending of the request even if interrupted */
295 	unsigned force:1;
296 
297 	/** The request was aborted */
298 	unsigned aborted:1;
299 
300 	/** Request is sent in the background */
301 	unsigned background:1;
302 
303 	/** The request has been interrupted */
304 	unsigned interrupted:1;
305 
306 	/** Data is being copied to/from the request */
307 	unsigned locked:1;
308 
309 	/** Request is counted as "waiting" */
310 	unsigned waiting:1;
311 
312 	/** State of the request */
313 	enum fuse_req_state state;
314 
315 	/** The request input */
316 	struct fuse_in in;
317 
318 	/** The request output */
319 	struct fuse_out out;
320 
321 	/** Used to wake up the task waiting for completion of request*/
322 	wait_queue_head_t waitq;
323 
324 	/** Data for asynchronous requests */
325 	union {
326 		struct {
327 			struct fuse_release_in in;
328 			struct inode *inode;
329 		} release;
330 		struct fuse_init_in init_in;
331 		struct fuse_init_out init_out;
332 		struct cuse_init_in cuse_init_in;
333 		struct {
334 			struct fuse_read_in in;
335 			u64 attr_ver;
336 		} read;
337 		struct {
338 			struct fuse_write_in in;
339 			struct fuse_write_out out;
340 			struct fuse_req *next;
341 		} write;
342 		struct fuse_notify_retrieve_in retrieve_in;
343 	} misc;
344 
345 	/** page vector */
346 	struct page **pages;
347 
348 	/** page-descriptor vector */
349 	struct fuse_page_desc *page_descs;
350 
351 	/** size of the 'pages' array */
352 	unsigned max_pages;
353 
354 	/** inline page vector */
355 	struct page *inline_pages[FUSE_REQ_INLINE_PAGES];
356 
357 	/** inline page-descriptor vector */
358 	struct fuse_page_desc inline_page_descs[FUSE_REQ_INLINE_PAGES];
359 
360 	/** number of pages in vector */
361 	unsigned num_pages;
362 
363 	/** File used in the request (or NULL) */
364 	struct fuse_file *ff;
365 
366 	/** Inode used in the request or NULL */
367 	struct inode *inode;
368 
369 	/** AIO control block */
370 	struct fuse_io_priv *io;
371 
372 	/** Link on fi->writepages */
373 	struct list_head writepages_entry;
374 
375 	/** Request completion callback */
376 	void (*end)(struct fuse_conn *, struct fuse_req *);
377 
378 	/** Request is stolen from fuse_file->reserved_req */
379 	struct file *stolen_file;
380 };
381 
382 /**
383  * A Fuse connection.
384  *
385  * This structure is created, when the filesystem is mounted, and is
386  * destroyed, when the client device is closed and the filesystem is
387  * unmounted.
388  */
389 struct fuse_conn {
390 	/** Lock protecting accessess to  members of this structure */
391 	spinlock_t lock;
392 
393 	/** Refcount */
394 	atomic_t count;
395 
396 	struct rcu_head rcu;
397 
398 	/** The user id for this mount */
399 	kuid_t user_id;
400 
401 	/** The group id for this mount */
402 	kgid_t group_id;
403 
404 	/** The fuse mount flags for this mount */
405 	unsigned flags;
406 
407 	/** Maximum read size */
408 	unsigned max_read;
409 
410 	/** Maximum write size */
411 	unsigned max_write;
412 
413 	/** Readers of the connection are waiting on this */
414 	wait_queue_head_t waitq;
415 
416 	/** The list of pending requests */
417 	struct list_head pending;
418 
419 	/** The list of requests being processed */
420 	struct list_head processing;
421 
422 	/** The list of requests under I/O */
423 	struct list_head io;
424 
425 	/** The next unique kernel file handle */
426 	u64 khctr;
427 
428 	/** rbtree of fuse_files waiting for poll events indexed by ph */
429 	struct rb_root polled_files;
430 
431 	/** Maximum number of outstanding background requests */
432 	unsigned max_background;
433 
434 	/** Number of background requests at which congestion starts */
435 	unsigned congestion_threshold;
436 
437 	/** Number of requests currently in the background */
438 	unsigned num_background;
439 
440 	/** Number of background requests currently queued for userspace */
441 	unsigned active_background;
442 
443 	/** The list of background requests set aside for later queuing */
444 	struct list_head bg_queue;
445 
446 	/** Pending interrupts */
447 	struct list_head interrupts;
448 
449 	/** Queue of pending forgets */
450 	struct fuse_forget_link forget_list_head;
451 	struct fuse_forget_link *forget_list_tail;
452 
453 	/** Batching of FORGET requests (positive indicates FORGET batch) */
454 	int forget_batch;
455 
456 	/** Flag indicating that INIT reply has been received. Allocating
457 	 * any fuse request will be suspended until the flag is set */
458 	int initialized;
459 
460 	/** Flag indicating if connection is blocked.  This will be
461 	    the case before the INIT reply is received, and if there
462 	    are too many outstading backgrounds requests */
463 	int blocked;
464 
465 	/** waitq for blocked connection */
466 	wait_queue_head_t blocked_waitq;
467 
468 	/** waitq for reserved requests */
469 	wait_queue_head_t reserved_req_waitq;
470 
471 	/** The next unique request id */
472 	u64 reqctr;
473 
474 	/** Connection established, cleared on umount, connection
475 	    abort and device release */
476 	unsigned connected;
477 
478 	/** Connection failed (version mismatch).  Cannot race with
479 	    setting other bitfields since it is only set once in INIT
480 	    reply, before any other request, and never cleared */
481 	unsigned conn_error:1;
482 
483 	/** Connection successful.  Only set in INIT */
484 	unsigned conn_init:1;
485 
486 	/** Do readpages asynchronously?  Only set in INIT */
487 	unsigned async_read:1;
488 
489 	/** Do not send separate SETATTR request before open(O_TRUNC)  */
490 	unsigned atomic_o_trunc:1;
491 
492 	/** Filesystem supports NFS exporting.  Only set in INIT */
493 	unsigned export_support:1;
494 
495 	/** Set if bdi is valid */
496 	unsigned bdi_initialized:1;
497 
498 	/** write-back cache policy (default is write-through) */
499 	unsigned writeback_cache:1;
500 
501 	/*
502 	 * The following bitfields are only for optimization purposes
503 	 * and hence races in setting them will not cause malfunction
504 	 */
505 
506 	/** Is open/release not implemented by fs? */
507 	unsigned no_open:1;
508 
509 	/** Is fsync not implemented by fs? */
510 	unsigned no_fsync:1;
511 
512 	/** Is fsyncdir not implemented by fs? */
513 	unsigned no_fsyncdir:1;
514 
515 	/** Is flush not implemented by fs? */
516 	unsigned no_flush:1;
517 
518 	/** Is setxattr not implemented by fs? */
519 	unsigned no_setxattr:1;
520 
521 	/** Is getxattr not implemented by fs? */
522 	unsigned no_getxattr:1;
523 
524 	/** Is listxattr not implemented by fs? */
525 	unsigned no_listxattr:1;
526 
527 	/** Is removexattr not implemented by fs? */
528 	unsigned no_removexattr:1;
529 
530 	/** Are posix file locking primitives not implemented by fs? */
531 	unsigned no_lock:1;
532 
533 	/** Is access not implemented by fs? */
534 	unsigned no_access:1;
535 
536 	/** Is create not implemented by fs? */
537 	unsigned no_create:1;
538 
539 	/** Is interrupt not implemented by fs? */
540 	unsigned no_interrupt:1;
541 
542 	/** Is bmap not implemented by fs? */
543 	unsigned no_bmap:1;
544 
545 	/** Is poll not implemented by fs? */
546 	unsigned no_poll:1;
547 
548 	/** Do multi-page cached writes */
549 	unsigned big_writes:1;
550 
551 	/** Don't apply umask to creation modes */
552 	unsigned dont_mask:1;
553 
554 	/** Are BSD file locking primitives not implemented by fs? */
555 	unsigned no_flock:1;
556 
557 	/** Is fallocate not implemented by fs? */
558 	unsigned no_fallocate:1;
559 
560 	/** Is rename with flags implemented by fs? */
561 	unsigned no_rename2:1;
562 
563 	/** Use enhanced/automatic page cache invalidation. */
564 	unsigned auto_inval_data:1;
565 
566 	/** Does the filesystem support readdirplus? */
567 	unsigned do_readdirplus:1;
568 
569 	/** Does the filesystem want adaptive readdirplus? */
570 	unsigned readdirplus_auto:1;
571 
572 	/** Does the filesystem support asynchronous direct-IO submission? */
573 	unsigned async_dio:1;
574 
575 	/** The number of requests waiting for completion */
576 	atomic_t num_waiting;
577 
578 	/** Negotiated minor version */
579 	unsigned minor;
580 
581 	/** Backing dev info */
582 	struct backing_dev_info bdi;
583 
584 	/** Entry on the fuse_conn_list */
585 	struct list_head entry;
586 
587 	/** Device ID from super block */
588 	dev_t dev;
589 
590 	/** Dentries in the control filesystem */
591 	struct dentry *ctl_dentry[FUSE_CTL_NUM_DENTRIES];
592 
593 	/** number of dentries used in the above array */
594 	int ctl_ndents;
595 
596 	/** O_ASYNC requests */
597 	struct fasync_struct *fasync;
598 
599 	/** Key for lock owner ID scrambling */
600 	u32 scramble_key[4];
601 
602 	/** Reserved request for the DESTROY message */
603 	struct fuse_req *destroy_req;
604 
605 	/** Version counter for attribute changes */
606 	u64 attr_version;
607 
608 	/** Called on final put */
609 	void (*release)(struct fuse_conn *);
610 
611 	/** Super block for this connection. */
612 	struct super_block *sb;
613 
614 	/** Read/write semaphore to hold when accessing sb. */
615 	struct rw_semaphore killsb;
616 };
617 
618 static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb)
619 {
620 	return sb->s_fs_info;
621 }
622 
623 static inline struct fuse_conn *get_fuse_conn(struct inode *inode)
624 {
625 	return get_fuse_conn_super(inode->i_sb);
626 }
627 
628 static inline struct fuse_inode *get_fuse_inode(struct inode *inode)
629 {
630 	return container_of(inode, struct fuse_inode, inode);
631 }
632 
633 static inline u64 get_node_id(struct inode *inode)
634 {
635 	return get_fuse_inode(inode)->nodeid;
636 }
637 
638 /** Device operations */
639 extern const struct file_operations fuse_dev_operations;
640 
641 extern const struct dentry_operations fuse_dentry_operations;
642 
643 /**
644  * Inode to nodeid comparison.
645  */
646 int fuse_inode_eq(struct inode *inode, void *_nodeidp);
647 
648 /**
649  * Get a filled in inode
650  */
651 struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
652 			int generation, struct fuse_attr *attr,
653 			u64 attr_valid, u64 attr_version);
654 
655 int fuse_lookup_name(struct super_block *sb, u64 nodeid, struct qstr *name,
656 		     struct fuse_entry_out *outarg, struct inode **inode);
657 
658 /**
659  * Send FORGET command
660  */
661 void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget,
662 		       u64 nodeid, u64 nlookup);
663 
664 struct fuse_forget_link *fuse_alloc_forget(void);
665 
666 /* Used by READDIRPLUS */
667 void fuse_force_forget(struct file *file, u64 nodeid);
668 
669 /**
670  * Initialize READ or READDIR request
671  */
672 void fuse_read_fill(struct fuse_req *req, struct file *file,
673 		    loff_t pos, size_t count, int opcode);
674 
675 /**
676  * Send OPEN or OPENDIR request
677  */
678 int fuse_open_common(struct inode *inode, struct file *file, bool isdir);
679 
680 struct fuse_file *fuse_file_alloc(struct fuse_conn *fc);
681 struct fuse_file *fuse_file_get(struct fuse_file *ff);
682 void fuse_file_free(struct fuse_file *ff);
683 void fuse_finish_open(struct inode *inode, struct file *file);
684 
685 void fuse_sync_release(struct fuse_file *ff, int flags);
686 
687 /**
688  * Send RELEASE or RELEASEDIR request
689  */
690 void fuse_release_common(struct file *file, int opcode);
691 
692 /**
693  * Send FSYNC or FSYNCDIR request
694  */
695 int fuse_fsync_common(struct file *file, loff_t start, loff_t end,
696 		      int datasync, int isdir);
697 
698 /**
699  * Notify poll wakeup
700  */
701 int fuse_notify_poll_wakeup(struct fuse_conn *fc,
702 			    struct fuse_notify_poll_wakeup_out *outarg);
703 
704 /**
705  * Initialize file operations on a regular file
706  */
707 void fuse_init_file_inode(struct inode *inode);
708 
709 /**
710  * Initialize inode operations on regular files and special files
711  */
712 void fuse_init_common(struct inode *inode);
713 
714 /**
715  * Initialize inode and file operations on a directory
716  */
717 void fuse_init_dir(struct inode *inode);
718 
719 /**
720  * Initialize inode operations on a symlink
721  */
722 void fuse_init_symlink(struct inode *inode);
723 
724 /**
725  * Change attributes of an inode
726  */
727 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
728 			    u64 attr_valid, u64 attr_version);
729 
730 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
731 				   u64 attr_valid);
732 
733 /**
734  * Initialize the client device
735  */
736 int fuse_dev_init(void);
737 
738 /**
739  * Cleanup the client device
740  */
741 void fuse_dev_cleanup(void);
742 
743 int fuse_ctl_init(void);
744 void __exit fuse_ctl_cleanup(void);
745 
746 /**
747  * Allocate a request
748  */
749 struct fuse_req *fuse_request_alloc(unsigned npages);
750 
751 struct fuse_req *fuse_request_alloc_nofs(unsigned npages);
752 
753 /**
754  * Free a request
755  */
756 void fuse_request_free(struct fuse_req *req);
757 
758 /**
759  * Get a request, may fail with -ENOMEM,
760  * caller should specify # elements in req->pages[] explicitly
761  */
762 struct fuse_req *fuse_get_req(struct fuse_conn *fc, unsigned npages);
763 struct fuse_req *fuse_get_req_for_background(struct fuse_conn *fc,
764 					     unsigned npages);
765 
766 /*
767  * Increment reference count on request
768  */
769 void __fuse_get_request(struct fuse_req *req);
770 
771 /**
772  * Gets a requests for a file operation, always succeeds
773  */
774 struct fuse_req *fuse_get_req_nofail_nopages(struct fuse_conn *fc,
775 					     struct file *file);
776 
777 /**
778  * Decrement reference count of a request.  If count goes to zero free
779  * the request.
780  */
781 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req);
782 
783 /**
784  * Send a request (synchronous)
785  */
786 void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req);
787 
788 /**
789  * Simple request sending that does request allocation and freeing
790  */
791 ssize_t fuse_simple_request(struct fuse_conn *fc, struct fuse_args *args);
792 
793 /**
794  * Send a request in the background
795  */
796 void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req);
797 
798 void fuse_request_send_background_locked(struct fuse_conn *fc,
799 					 struct fuse_req *req);
800 
801 /* Abort all requests */
802 void fuse_abort_conn(struct fuse_conn *fc);
803 
804 /**
805  * Invalidate inode attributes
806  */
807 void fuse_invalidate_attr(struct inode *inode);
808 
809 void fuse_invalidate_entry_cache(struct dentry *entry);
810 
811 void fuse_invalidate_atime(struct inode *inode);
812 
813 /**
814  * Acquire reference to fuse_conn
815  */
816 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc);
817 
818 /**
819  * Initialize fuse_conn
820  */
821 void fuse_conn_init(struct fuse_conn *fc);
822 
823 /**
824  * Release reference to fuse_conn
825  */
826 void fuse_conn_put(struct fuse_conn *fc);
827 
828 /**
829  * Add connection to control filesystem
830  */
831 int fuse_ctl_add_conn(struct fuse_conn *fc);
832 
833 /**
834  * Remove connection from control filesystem
835  */
836 void fuse_ctl_remove_conn(struct fuse_conn *fc);
837 
838 /**
839  * Is file type valid?
840  */
841 int fuse_valid_type(int m);
842 
843 /**
844  * Is current process allowed to perform filesystem operation?
845  */
846 int fuse_allow_current_process(struct fuse_conn *fc);
847 
848 u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id);
849 
850 int fuse_update_attributes(struct inode *inode, struct kstat *stat,
851 			   struct file *file, bool *refreshed);
852 
853 void fuse_flush_writepages(struct inode *inode);
854 
855 void fuse_set_nowrite(struct inode *inode);
856 void fuse_release_nowrite(struct inode *inode);
857 
858 u64 fuse_get_attr_version(struct fuse_conn *fc);
859 
860 /**
861  * File-system tells the kernel to invalidate cache for the given node id.
862  */
863 int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid,
864 			     loff_t offset, loff_t len);
865 
866 /**
867  * File-system tells the kernel to invalidate parent attributes and
868  * the dentry matching parent/name.
869  *
870  * If the child_nodeid is non-zero and:
871  *    - matches the inode number for the dentry matching parent/name,
872  *    - is not a mount point
873  *    - is a file or oan empty directory
874  * then the dentry is unhashed (d_delete()).
875  */
876 int fuse_reverse_inval_entry(struct super_block *sb, u64 parent_nodeid,
877 			     u64 child_nodeid, struct qstr *name);
878 
879 int fuse_do_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
880 		 bool isdir);
881 
882 /**
883  * fuse_direct_io() flags
884  */
885 
886 /** If set, it is WRITE; otherwise - READ */
887 #define FUSE_DIO_WRITE (1 << 0)
888 
889 /** CUSE pass fuse_direct_io() a file which f_mapping->host is not from FUSE */
890 #define FUSE_DIO_CUSE  (1 << 1)
891 
892 ssize_t fuse_direct_io(struct fuse_io_priv *io, struct iov_iter *iter,
893 		       loff_t *ppos, int flags);
894 long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
895 		   unsigned int flags);
896 long fuse_ioctl_common(struct file *file, unsigned int cmd,
897 		       unsigned long arg, unsigned int flags);
898 unsigned fuse_file_poll(struct file *file, poll_table *wait);
899 int fuse_dev_release(struct inode *inode, struct file *file);
900 
901 bool fuse_write_update_size(struct inode *inode, loff_t pos);
902 
903 int fuse_flush_times(struct inode *inode, struct fuse_file *ff);
904 int fuse_write_inode(struct inode *inode, struct writeback_control *wbc);
905 
906 int fuse_do_setattr(struct inode *inode, struct iattr *attr,
907 		    struct file *file);
908 
909 void fuse_set_initialized(struct fuse_conn *fc);
910 
911 #endif /* _FS_FUSE_I_H */
912