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 state */
246 enum fuse_req_state {
247 	FUSE_REQ_INIT = 0,
248 	FUSE_REQ_PENDING,
249 	FUSE_REQ_READING,
250 	FUSE_REQ_SENT,
251 	FUSE_REQ_WRITING,
252 	FUSE_REQ_FINISHED
253 };
254 
255 /** The request IO state (for asynchronous processing) */
256 struct fuse_io_priv {
257 	struct kref refcnt;
258 	int async;
259 	spinlock_t lock;
260 	unsigned reqs;
261 	ssize_t bytes;
262 	size_t size;
263 	__u64 offset;
264 	bool write;
265 	int err;
266 	struct kiocb *iocb;
267 	struct file *file;
268 	struct completion *done;
269 };
270 
271 #define FUSE_IO_PRIV_SYNC(f) \
272 {					\
273 	.refcnt = { ATOMIC_INIT(1) },	\
274 	.async = 0,			\
275 	.file = f,			\
276 }
277 
278 /**
279  * A request to the client
280  */
281 struct fuse_req {
282 	/** This can be on either pending processing or io lists in
283 	    fuse_conn */
284 	struct list_head list;
285 
286 	/** Entry on the interrupts list  */
287 	struct list_head intr_entry;
288 
289 	/** refcount */
290 	atomic_t count;
291 
292 	/** Unique ID for the interrupt request */
293 	u64 intr_unique;
294 
295 	/*
296 	 * The following bitfields are either set once before the
297 	 * request is queued or setting/clearing them is protected by
298 	 * fuse_conn->lock
299 	 */
300 
301 	/** True if the request has reply */
302 	unsigned isreply:1;
303 
304 	/** Force sending of the request even if interrupted */
305 	unsigned force:1;
306 
307 	/** The request was aborted */
308 	unsigned aborted:1;
309 
310 	/** Request is sent in the background */
311 	unsigned background:1;
312 
313 	/** The request has been interrupted */
314 	unsigned interrupted:1;
315 
316 	/** Data is being copied to/from the request */
317 	unsigned locked:1;
318 
319 	/** Request is counted as "waiting" */
320 	unsigned waiting:1;
321 
322 	/** State of the request */
323 	enum fuse_req_state state;
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 /**
393  * A Fuse connection.
394  *
395  * This structure is created, when the filesystem is mounted, and is
396  * destroyed, when the client device is closed and the filesystem is
397  * unmounted.
398  */
399 struct fuse_conn {
400 	/** Lock protecting accessess to  members of this structure */
401 	spinlock_t lock;
402 
403 	/** Refcount */
404 	atomic_t count;
405 
406 	struct rcu_head rcu;
407 
408 	/** The user id for this mount */
409 	kuid_t user_id;
410 
411 	/** The group id for this mount */
412 	kgid_t group_id;
413 
414 	/** The fuse mount flags for this mount */
415 	unsigned flags;
416 
417 	/** Maximum read size */
418 	unsigned max_read;
419 
420 	/** Maximum write size */
421 	unsigned max_write;
422 
423 	/** Readers of the connection are waiting on this */
424 	wait_queue_head_t waitq;
425 
426 	/** The list of pending requests */
427 	struct list_head pending;
428 
429 	/** The list of requests being processed */
430 	struct list_head processing;
431 
432 	/** The list of requests under I/O */
433 	struct list_head io;
434 
435 	/** The next unique kernel file handle */
436 	u64 khctr;
437 
438 	/** rbtree of fuse_files waiting for poll events indexed by ph */
439 	struct rb_root polled_files;
440 
441 	/** Maximum number of outstanding background requests */
442 	unsigned max_background;
443 
444 	/** Number of background requests at which congestion starts */
445 	unsigned congestion_threshold;
446 
447 	/** Number of requests currently in the background */
448 	unsigned num_background;
449 
450 	/** Number of background requests currently queued for userspace */
451 	unsigned active_background;
452 
453 	/** The list of background requests set aside for later queuing */
454 	struct list_head bg_queue;
455 
456 	/** Pending interrupts */
457 	struct list_head interrupts;
458 
459 	/** Queue of pending forgets */
460 	struct fuse_forget_link forget_list_head;
461 	struct fuse_forget_link *forget_list_tail;
462 
463 	/** Batching of FORGET requests (positive indicates FORGET batch) */
464 	int forget_batch;
465 
466 	/** Flag indicating that INIT reply has been received. Allocating
467 	 * any fuse request will be suspended until the flag is set */
468 	int initialized;
469 
470 	/** Flag indicating if connection is blocked.  This will be
471 	    the case before the INIT reply is received, and if there
472 	    are too many outstading backgrounds requests */
473 	int blocked;
474 
475 	/** waitq for blocked connection */
476 	wait_queue_head_t blocked_waitq;
477 
478 	/** waitq for reserved requests */
479 	wait_queue_head_t reserved_req_waitq;
480 
481 	/** The next unique request id */
482 	u64 reqctr;
483 
484 	/** Connection established, cleared on umount, connection
485 	    abort and device release */
486 	unsigned connected;
487 
488 	/** Connection failed (version mismatch).  Cannot race with
489 	    setting other bitfields since it is only set once in INIT
490 	    reply, before any other request, and never cleared */
491 	unsigned conn_error:1;
492 
493 	/** Connection successful.  Only set in INIT */
494 	unsigned conn_init:1;
495 
496 	/** Do readpages asynchronously?  Only set in INIT */
497 	unsigned async_read:1;
498 
499 	/** Do not send separate SETATTR request before open(O_TRUNC)  */
500 	unsigned atomic_o_trunc:1;
501 
502 	/** Filesystem supports NFS exporting.  Only set in INIT */
503 	unsigned export_support:1;
504 
505 	/** Set if bdi is valid */
506 	unsigned bdi_initialized:1;
507 
508 	/** write-back cache policy (default is write-through) */
509 	unsigned writeback_cache:1;
510 
511 	/*
512 	 * The following bitfields are only for optimization purposes
513 	 * and hence races in setting them will not cause malfunction
514 	 */
515 
516 	/** Is open/release not implemented by fs? */
517 	unsigned no_open:1;
518 
519 	/** Is fsync not implemented by fs? */
520 	unsigned no_fsync:1;
521 
522 	/** Is fsyncdir not implemented by fs? */
523 	unsigned no_fsyncdir:1;
524 
525 	/** Is flush not implemented by fs? */
526 	unsigned no_flush:1;
527 
528 	/** Is setxattr not implemented by fs? */
529 	unsigned no_setxattr:1;
530 
531 	/** Is getxattr not implemented by fs? */
532 	unsigned no_getxattr:1;
533 
534 	/** Is listxattr not implemented by fs? */
535 	unsigned no_listxattr:1;
536 
537 	/** Is removexattr not implemented by fs? */
538 	unsigned no_removexattr:1;
539 
540 	/** Are posix file locking primitives not implemented by fs? */
541 	unsigned no_lock:1;
542 
543 	/** Is access not implemented by fs? */
544 	unsigned no_access:1;
545 
546 	/** Is create not implemented by fs? */
547 	unsigned no_create:1;
548 
549 	/** Is interrupt not implemented by fs? */
550 	unsigned no_interrupt:1;
551 
552 	/** Is bmap not implemented by fs? */
553 	unsigned no_bmap:1;
554 
555 	/** Is poll not implemented by fs? */
556 	unsigned no_poll:1;
557 
558 	/** Do multi-page cached writes */
559 	unsigned big_writes:1;
560 
561 	/** Don't apply umask to creation modes */
562 	unsigned dont_mask:1;
563 
564 	/** Are BSD file locking primitives not implemented by fs? */
565 	unsigned no_flock:1;
566 
567 	/** Is fallocate not implemented by fs? */
568 	unsigned no_fallocate:1;
569 
570 	/** Is rename with flags implemented by fs? */
571 	unsigned no_rename2:1;
572 
573 	/** Use enhanced/automatic page cache invalidation. */
574 	unsigned auto_inval_data:1;
575 
576 	/** Does the filesystem support readdirplus? */
577 	unsigned do_readdirplus:1;
578 
579 	/** Does the filesystem want adaptive readdirplus? */
580 	unsigned readdirplus_auto:1;
581 
582 	/** Does the filesystem support asynchronous direct-IO submission? */
583 	unsigned async_dio:1;
584 
585 	/** The number of requests waiting for completion */
586 	atomic_t num_waiting;
587 
588 	/** Negotiated minor version */
589 	unsigned minor;
590 
591 	/** Backing dev info */
592 	struct backing_dev_info bdi;
593 
594 	/** Entry on the fuse_conn_list */
595 	struct list_head entry;
596 
597 	/** Device ID from super block */
598 	dev_t dev;
599 
600 	/** Dentries in the control filesystem */
601 	struct dentry *ctl_dentry[FUSE_CTL_NUM_DENTRIES];
602 
603 	/** number of dentries used in the above array */
604 	int ctl_ndents;
605 
606 	/** O_ASYNC requests */
607 	struct fasync_struct *fasync;
608 
609 	/** Key for lock owner ID scrambling */
610 	u32 scramble_key[4];
611 
612 	/** Reserved request for the DESTROY message */
613 	struct fuse_req *destroy_req;
614 
615 	/** Version counter for attribute changes */
616 	u64 attr_version;
617 
618 	/** Called on final put */
619 	void (*release)(struct fuse_conn *);
620 
621 	/** Super block for this connection. */
622 	struct super_block *sb;
623 
624 	/** Read/write semaphore to hold when accessing sb. */
625 	struct rw_semaphore killsb;
626 };
627 
get_fuse_conn_super(struct super_block * sb)628 static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb)
629 {
630 	return sb->s_fs_info;
631 }
632 
get_fuse_conn(struct inode * inode)633 static inline struct fuse_conn *get_fuse_conn(struct inode *inode)
634 {
635 	return get_fuse_conn_super(inode->i_sb);
636 }
637 
get_fuse_inode(struct inode * inode)638 static inline struct fuse_inode *get_fuse_inode(struct inode *inode)
639 {
640 	return container_of(inode, struct fuse_inode, inode);
641 }
642 
get_node_id(struct inode * inode)643 static inline u64 get_node_id(struct inode *inode)
644 {
645 	return get_fuse_inode(inode)->nodeid;
646 }
647 
648 /** Device operations */
649 extern const struct file_operations fuse_dev_operations;
650 
651 extern const struct dentry_operations fuse_dentry_operations;
652 
653 /**
654  * Inode to nodeid comparison.
655  */
656 int fuse_inode_eq(struct inode *inode, void *_nodeidp);
657 
658 /**
659  * Get a filled in inode
660  */
661 struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
662 			int generation, struct fuse_attr *attr,
663 			u64 attr_valid, u64 attr_version);
664 
665 int fuse_lookup_name(struct super_block *sb, u64 nodeid, struct qstr *name,
666 		     struct fuse_entry_out *outarg, struct inode **inode);
667 
668 /**
669  * Send FORGET command
670  */
671 void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget,
672 		       u64 nodeid, u64 nlookup);
673 
674 struct fuse_forget_link *fuse_alloc_forget(void);
675 
676 /* Used by READDIRPLUS */
677 void fuse_force_forget(struct file *file, u64 nodeid);
678 
679 /**
680  * Initialize READ or READDIR request
681  */
682 void fuse_read_fill(struct fuse_req *req, struct file *file,
683 		    loff_t pos, size_t count, int opcode);
684 
685 /**
686  * Send OPEN or OPENDIR request
687  */
688 int fuse_open_common(struct inode *inode, struct file *file, bool isdir);
689 
690 struct fuse_file *fuse_file_alloc(struct fuse_conn *fc);
691 struct fuse_file *fuse_file_get(struct fuse_file *ff);
692 void fuse_file_free(struct fuse_file *ff);
693 void fuse_finish_open(struct inode *inode, struct file *file);
694 
695 void fuse_sync_release(struct fuse_file *ff, int flags);
696 
697 /**
698  * Send RELEASE or RELEASEDIR request
699  */
700 void fuse_release_common(struct file *file, int opcode);
701 
702 /**
703  * Send FSYNC or FSYNCDIR request
704  */
705 int fuse_fsync_common(struct file *file, loff_t start, loff_t end,
706 		      int datasync, int isdir);
707 
708 /**
709  * Notify poll wakeup
710  */
711 int fuse_notify_poll_wakeup(struct fuse_conn *fc,
712 			    struct fuse_notify_poll_wakeup_out *outarg);
713 
714 /**
715  * Initialize file operations on a regular file
716  */
717 void fuse_init_file_inode(struct inode *inode);
718 
719 /**
720  * Initialize inode operations on regular files and special files
721  */
722 void fuse_init_common(struct inode *inode);
723 
724 /**
725  * Initialize inode and file operations on a directory
726  */
727 void fuse_init_dir(struct inode *inode);
728 
729 /**
730  * Initialize inode operations on a symlink
731  */
732 void fuse_init_symlink(struct inode *inode);
733 
734 /**
735  * Change attributes of an inode
736  */
737 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
738 			    u64 attr_valid, u64 attr_version);
739 
740 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
741 				   u64 attr_valid);
742 
743 /**
744  * Initialize the client device
745  */
746 int fuse_dev_init(void);
747 
748 /**
749  * Cleanup the client device
750  */
751 void fuse_dev_cleanup(void);
752 
753 int fuse_ctl_init(void);
754 void __exit fuse_ctl_cleanup(void);
755 
756 /**
757  * Allocate a request
758  */
759 struct fuse_req *fuse_request_alloc(unsigned npages);
760 
761 struct fuse_req *fuse_request_alloc_nofs(unsigned npages);
762 
763 /**
764  * Free a request
765  */
766 void fuse_request_free(struct fuse_req *req);
767 
768 /**
769  * Get a request, may fail with -ENOMEM,
770  * caller should specify # elements in req->pages[] explicitly
771  */
772 struct fuse_req *fuse_get_req(struct fuse_conn *fc, unsigned npages);
773 struct fuse_req *fuse_get_req_for_background(struct fuse_conn *fc,
774 					     unsigned npages);
775 
776 /*
777  * Increment reference count on request
778  */
779 void __fuse_get_request(struct fuse_req *req);
780 
781 /**
782  * Gets a requests for a file operation, always succeeds
783  */
784 struct fuse_req *fuse_get_req_nofail_nopages(struct fuse_conn *fc,
785 					     struct file *file);
786 
787 /**
788  * Decrement reference count of a request.  If count goes to zero free
789  * the request.
790  */
791 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req);
792 
793 /**
794  * Send a request (synchronous)
795  */
796 void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req);
797 
798 /**
799  * Simple request sending that does request allocation and freeing
800  */
801 ssize_t fuse_simple_request(struct fuse_conn *fc, struct fuse_args *args);
802 
803 /**
804  * Send a request in the background
805  */
806 void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req);
807 
808 void fuse_request_send_background_locked(struct fuse_conn *fc,
809 					 struct fuse_req *req);
810 
811 /* Abort all requests */
812 void fuse_abort_conn(struct fuse_conn *fc);
813 
814 /**
815  * Invalidate inode attributes
816  */
817 void fuse_invalidate_attr(struct inode *inode);
818 
819 void fuse_invalidate_entry_cache(struct dentry *entry);
820 
821 void fuse_invalidate_atime(struct inode *inode);
822 
823 /**
824  * Acquire reference to fuse_conn
825  */
826 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc);
827 
828 /**
829  * Initialize fuse_conn
830  */
831 void fuse_conn_init(struct fuse_conn *fc);
832 
833 /**
834  * Release reference to fuse_conn
835  */
836 void fuse_conn_put(struct fuse_conn *fc);
837 
838 /**
839  * Add connection to control filesystem
840  */
841 int fuse_ctl_add_conn(struct fuse_conn *fc);
842 
843 /**
844  * Remove connection from control filesystem
845  */
846 void fuse_ctl_remove_conn(struct fuse_conn *fc);
847 
848 /**
849  * Is file type valid?
850  */
851 int fuse_valid_type(int m);
852 
853 /**
854  * Is current process allowed to perform filesystem operation?
855  */
856 int fuse_allow_current_process(struct fuse_conn *fc);
857 
858 u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id);
859 
860 int fuse_update_attributes(struct inode *inode, struct kstat *stat,
861 			   struct file *file, bool *refreshed);
862 
863 void fuse_flush_writepages(struct inode *inode);
864 
865 void fuse_set_nowrite(struct inode *inode);
866 void fuse_release_nowrite(struct inode *inode);
867 
868 u64 fuse_get_attr_version(struct fuse_conn *fc);
869 
870 /**
871  * File-system tells the kernel to invalidate cache for the given node id.
872  */
873 int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid,
874 			     loff_t offset, loff_t len);
875 
876 /**
877  * File-system tells the kernel to invalidate parent attributes and
878  * the dentry matching parent/name.
879  *
880  * If the child_nodeid is non-zero and:
881  *    - matches the inode number for the dentry matching parent/name,
882  *    - is not a mount point
883  *    - is a file or oan empty directory
884  * then the dentry is unhashed (d_delete()).
885  */
886 int fuse_reverse_inval_entry(struct super_block *sb, u64 parent_nodeid,
887 			     u64 child_nodeid, struct qstr *name);
888 
889 int fuse_do_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
890 		 bool isdir);
891 
892 /**
893  * fuse_direct_io() flags
894  */
895 
896 /** If set, it is WRITE; otherwise - READ */
897 #define FUSE_DIO_WRITE (1 << 0)
898 
899 /** CUSE pass fuse_direct_io() a file which f_mapping->host is not from FUSE */
900 #define FUSE_DIO_CUSE  (1 << 1)
901 
902 ssize_t fuse_direct_io(struct fuse_io_priv *io, struct iov_iter *iter,
903 		       loff_t *ppos, int flags);
904 long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
905 		   unsigned int flags);
906 long fuse_ioctl_common(struct file *file, unsigned int cmd,
907 		       unsigned long arg, unsigned int flags);
908 unsigned fuse_file_poll(struct file *file, poll_table *wait);
909 int fuse_dev_release(struct inode *inode, struct file *file);
910 
911 bool fuse_write_update_size(struct inode *inode, loff_t pos);
912 
913 int fuse_flush_times(struct inode *inode, struct fuse_file *ff);
914 int fuse_write_inode(struct inode *inode, struct writeback_control *wbc);
915 
916 int fuse_do_setattr(struct inode *inode, struct iattr *attr,
917 		    struct file *file);
918 
919 void fuse_set_initialized(struct fuse_conn *fc);
920 
921 #endif /* _FS_FUSE_I_H */
922