xref: /linux/fs/fuse/fuse_i.h (revision f3a8b6645dc2e60d11f20c1c23afd964ff4e55ae)
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 #include <linux/xattr.h>
27 
28 /** Max number of pages that can be used in a single read request */
29 #define FUSE_MAX_PAGES_PER_REQ 32
30 
31 /** Bias for fi->writectr, meaning new writepages must not be sent */
32 #define FUSE_NOWRITE INT_MIN
33 
34 /** It could be as large as PATH_MAX, but would that have any uses? */
35 #define FUSE_NAME_MAX 1024
36 
37 /** Number of dentries for each connection in the control filesystem */
38 #define FUSE_CTL_NUM_DENTRIES 5
39 
40 /** Number of page pointers embedded in fuse_req */
41 #define FUSE_REQ_INLINE_PAGES 1
42 
43 /** List of active connections */
44 extern struct list_head fuse_conn_list;
45 
46 /** Global mutex protecting fuse_conn_list and the control filesystem */
47 extern struct mutex fuse_mutex;
48 
49 /** Module parameters */
50 extern unsigned max_user_bgreq;
51 extern unsigned max_user_congthresh;
52 
53 /* One forget request */
54 struct fuse_forget_link {
55 	struct fuse_forget_one forget_one;
56 	struct fuse_forget_link *next;
57 };
58 
59 /** FUSE inode */
60 struct fuse_inode {
61 	/** Inode data */
62 	struct inode inode;
63 
64 	/** Unique ID, which identifies the inode between userspace
65 	 * and kernel */
66 	u64 nodeid;
67 
68 	/** Number of lookups on this inode */
69 	u64 nlookup;
70 
71 	/** The request used for sending the FORGET message */
72 	struct fuse_forget_link *forget;
73 
74 	/** Time in jiffies until the file attributes are valid */
75 	u64 i_time;
76 
77 	/** The sticky bit in inode->i_mode may have been removed, so
78 	    preserve the original mode */
79 	umode_t orig_i_mode;
80 
81 	/** 64 bit inode number */
82 	u64 orig_ino;
83 
84 	/** Version of last attribute change */
85 	u64 attr_version;
86 
87 	/** Files usable in writepage.  Protected by fc->lock */
88 	struct list_head write_files;
89 
90 	/** Writepages pending on truncate or fsync */
91 	struct list_head queued_writes;
92 
93 	/** Number of sent writes, a negative bias (FUSE_NOWRITE)
94 	 * means more writes are blocked */
95 	int writectr;
96 
97 	/** Waitq for writepage completion */
98 	wait_queue_head_t page_waitq;
99 
100 	/** List of writepage requestst (pending or sent) */
101 	struct list_head writepages;
102 
103 	/** Miscellaneous bits describing inode state */
104 	unsigned long state;
105 
106 	/** Lock for serializing lookup and readdir for back compatibility*/
107 	struct mutex mutex;
108 };
109 
110 /** FUSE inode state bits */
111 enum {
112 	/** Advise readdirplus  */
113 	FUSE_I_ADVISE_RDPLUS,
114 	/** Initialized with readdirplus */
115 	FUSE_I_INIT_RDPLUS,
116 	/** An operation changing file size is in progress  */
117 	FUSE_I_SIZE_UNSTABLE,
118 };
119 
120 struct fuse_conn;
121 
122 /** FUSE specific file data */
123 struct fuse_file {
124 	/** Fuse connection for this file */
125 	struct fuse_conn *fc;
126 
127 	/** Request reserved for flush and release */
128 	struct fuse_req *reserved_req;
129 
130 	/** Kernel file handle guaranteed to be unique */
131 	u64 kh;
132 
133 	/** File handle used by userspace */
134 	u64 fh;
135 
136 	/** Node id of this file */
137 	u64 nodeid;
138 
139 	/** Refcount */
140 	atomic_t count;
141 
142 	/** FOPEN_* flags returned by open */
143 	u32 open_flags;
144 
145 	/** Entry on inode's write_files list */
146 	struct list_head write_entry;
147 
148 	/** RB node to be linked on fuse_conn->polled_files */
149 	struct rb_node polled_node;
150 
151 	/** Wait queue head for poll */
152 	wait_queue_head_t poll_wait;
153 
154 	/** Has flock been performed on this file? */
155 	bool flock:1;
156 };
157 
158 /** One input argument of a request */
159 struct fuse_in_arg {
160 	unsigned size;
161 	const void *value;
162 };
163 
164 /** The request input */
165 struct fuse_in {
166 	/** The request header */
167 	struct fuse_in_header h;
168 
169 	/** True if the data for the last argument is in req->pages */
170 	unsigned argpages:1;
171 
172 	/** Number of arguments */
173 	unsigned numargs;
174 
175 	/** Array of arguments */
176 	struct fuse_in_arg args[3];
177 };
178 
179 /** One output argument of a request */
180 struct fuse_arg {
181 	unsigned size;
182 	void *value;
183 };
184 
185 /** The request output */
186 struct fuse_out {
187 	/** Header returned from userspace */
188 	struct fuse_out_header h;
189 
190 	/*
191 	 * The following bitfields are not changed during the request
192 	 * processing
193 	 */
194 
195 	/** Last argument is variable length (can be shorter than
196 	    arg->size) */
197 	unsigned argvar:1;
198 
199 	/** Last argument is a list of pages to copy data to */
200 	unsigned argpages:1;
201 
202 	/** Zero partially or not copied pages */
203 	unsigned page_zeroing:1;
204 
205 	/** Pages may be replaced with new ones */
206 	unsigned page_replace:1;
207 
208 	/** Number or arguments */
209 	unsigned numargs;
210 
211 	/** Array of arguments */
212 	struct fuse_arg args[2];
213 };
214 
215 /** FUSE page descriptor */
216 struct fuse_page_desc {
217 	unsigned int length;
218 	unsigned int offset;
219 };
220 
221 struct fuse_args {
222 	struct {
223 		struct {
224 			uint32_t opcode;
225 			uint64_t nodeid;
226 		} h;
227 		unsigned numargs;
228 		struct fuse_in_arg args[3];
229 
230 	} in;
231 	struct {
232 		unsigned argvar:1;
233 		unsigned numargs;
234 		struct fuse_arg args[2];
235 	} out;
236 };
237 
238 #define FUSE_ARGS(args) struct fuse_args args = {}
239 
240 /** The request IO state (for asynchronous processing) */
241 struct fuse_io_priv {
242 	struct kref refcnt;
243 	int async;
244 	spinlock_t lock;
245 	unsigned reqs;
246 	ssize_t bytes;
247 	size_t size;
248 	__u64 offset;
249 	bool write;
250 	int err;
251 	struct kiocb *iocb;
252 	struct file *file;
253 	struct completion *done;
254 	bool blocking;
255 };
256 
257 #define FUSE_IO_PRIV_SYNC(f) \
258 {					\
259 	.refcnt = { ATOMIC_INIT(1) },	\
260 	.async = 0,			\
261 	.file = f,			\
262 }
263 
264 /**
265  * Request flags
266  *
267  * FR_ISREPLY:		set if the request has reply
268  * FR_FORCE:		force sending of the request even if interrupted
269  * FR_BACKGROUND:	request is sent in the background
270  * FR_WAITING:		request is counted as "waiting"
271  * FR_ABORTED:		the request was aborted
272  * FR_INTERRUPTED:	the request has been interrupted
273  * FR_LOCKED:		data is being copied to/from the request
274  * FR_PENDING:		request is not yet in userspace
275  * FR_SENT:		request is in userspace, waiting for an answer
276  * FR_FINISHED:		request is finished
277  * FR_PRIVATE:		request is on private list
278  */
279 enum fuse_req_flag {
280 	FR_ISREPLY,
281 	FR_FORCE,
282 	FR_BACKGROUND,
283 	FR_WAITING,
284 	FR_ABORTED,
285 	FR_INTERRUPTED,
286 	FR_LOCKED,
287 	FR_PENDING,
288 	FR_SENT,
289 	FR_FINISHED,
290 	FR_PRIVATE,
291 };
292 
293 /**
294  * A request to the client
295  *
296  * .waitq.lock protects the following fields:
297  *   - FR_ABORTED
298  *   - FR_LOCKED (may also be modified under fc->lock, tested under both)
299  */
300 struct fuse_req {
301 	/** This can be on either pending processing or io lists in
302 	    fuse_conn */
303 	struct list_head list;
304 
305 	/** Entry on the interrupts list  */
306 	struct list_head intr_entry;
307 
308 	/** refcount */
309 	atomic_t count;
310 
311 	/** Unique ID for the interrupt request */
312 	u64 intr_unique;
313 
314 	/* Request flags, updated with test/set/clear_bit() */
315 	unsigned long flags;
316 
317 	/** The request input */
318 	struct fuse_in in;
319 
320 	/** The request output */
321 	struct fuse_out out;
322 
323 	/** Used to wake up the task waiting for completion of request*/
324 	wait_queue_head_t waitq;
325 
326 	/** Data for asynchronous requests */
327 	union {
328 		struct {
329 			struct fuse_release_in in;
330 			struct inode *inode;
331 		} release;
332 		struct fuse_init_in init_in;
333 		struct fuse_init_out init_out;
334 		struct cuse_init_in cuse_init_in;
335 		struct {
336 			struct fuse_read_in in;
337 			u64 attr_ver;
338 		} read;
339 		struct {
340 			struct fuse_write_in in;
341 			struct fuse_write_out out;
342 			struct fuse_req *next;
343 		} write;
344 		struct fuse_notify_retrieve_in retrieve_in;
345 	} misc;
346 
347 	/** page vector */
348 	struct page **pages;
349 
350 	/** page-descriptor vector */
351 	struct fuse_page_desc *page_descs;
352 
353 	/** size of the 'pages' array */
354 	unsigned max_pages;
355 
356 	/** inline page vector */
357 	struct page *inline_pages[FUSE_REQ_INLINE_PAGES];
358 
359 	/** inline page-descriptor vector */
360 	struct fuse_page_desc inline_page_descs[FUSE_REQ_INLINE_PAGES];
361 
362 	/** number of pages in vector */
363 	unsigned num_pages;
364 
365 	/** File used in the request (or NULL) */
366 	struct fuse_file *ff;
367 
368 	/** Inode used in the request or NULL */
369 	struct inode *inode;
370 
371 	/** AIO control block */
372 	struct fuse_io_priv *io;
373 
374 	/** Link on fi->writepages */
375 	struct list_head writepages_entry;
376 
377 	/** Request completion callback */
378 	void (*end)(struct fuse_conn *, struct fuse_req *);
379 
380 	/** Request is stolen from fuse_file->reserved_req */
381 	struct file *stolen_file;
382 };
383 
384 struct fuse_iqueue {
385 	/** Connection established */
386 	unsigned connected;
387 
388 	/** Readers of the connection are waiting on this */
389 	wait_queue_head_t waitq;
390 
391 	/** The next unique request id */
392 	u64 reqctr;
393 
394 	/** The list of pending requests */
395 	struct list_head pending;
396 
397 	/** Pending interrupts */
398 	struct list_head interrupts;
399 
400 	/** Queue of pending forgets */
401 	struct fuse_forget_link forget_list_head;
402 	struct fuse_forget_link *forget_list_tail;
403 
404 	/** Batching of FORGET requests (positive indicates FORGET batch) */
405 	int forget_batch;
406 
407 	/** O_ASYNC requests */
408 	struct fasync_struct *fasync;
409 };
410 
411 struct fuse_pqueue {
412 	/** Connection established */
413 	unsigned connected;
414 
415 	/** Lock protecting accessess to  members of this structure */
416 	spinlock_t lock;
417 
418 	/** The list of requests being processed */
419 	struct list_head processing;
420 
421 	/** The list of requests under I/O */
422 	struct list_head io;
423 };
424 
425 /**
426  * Fuse device instance
427  */
428 struct fuse_dev {
429 	/** Fuse connection for this device */
430 	struct fuse_conn *fc;
431 
432 	/** Processing queue */
433 	struct fuse_pqueue pq;
434 
435 	/** list entry on fc->devices */
436 	struct list_head entry;
437 };
438 
439 /**
440  * A Fuse connection.
441  *
442  * This structure is created, when the filesystem is mounted, and is
443  * destroyed, when the client device is closed and the filesystem is
444  * unmounted.
445  */
446 struct fuse_conn {
447 	/** Lock protecting accessess to  members of this structure */
448 	spinlock_t lock;
449 
450 	/** Refcount */
451 	atomic_t count;
452 
453 	/** Number of fuse_dev's */
454 	atomic_t dev_count;
455 
456 	struct rcu_head rcu;
457 
458 	/** The user id for this mount */
459 	kuid_t user_id;
460 
461 	/** The group id for this mount */
462 	kgid_t group_id;
463 
464 	/** Maximum read size */
465 	unsigned max_read;
466 
467 	/** Maximum write size */
468 	unsigned max_write;
469 
470 	/** Input queue */
471 	struct fuse_iqueue iq;
472 
473 	/** The next unique kernel file handle */
474 	u64 khctr;
475 
476 	/** rbtree of fuse_files waiting for poll events indexed by ph */
477 	struct rb_root polled_files;
478 
479 	/** Maximum number of outstanding background requests */
480 	unsigned max_background;
481 
482 	/** Number of background requests at which congestion starts */
483 	unsigned congestion_threshold;
484 
485 	/** Number of requests currently in the background */
486 	unsigned num_background;
487 
488 	/** Number of background requests currently queued for userspace */
489 	unsigned active_background;
490 
491 	/** The list of background requests set aside for later queuing */
492 	struct list_head bg_queue;
493 
494 	/** Flag indicating that INIT reply has been received. Allocating
495 	 * any fuse request will be suspended until the flag is set */
496 	int initialized;
497 
498 	/** Flag indicating if connection is blocked.  This will be
499 	    the case before the INIT reply is received, and if there
500 	    are too many outstading backgrounds requests */
501 	int blocked;
502 
503 	/** waitq for blocked connection */
504 	wait_queue_head_t blocked_waitq;
505 
506 	/** waitq for reserved requests */
507 	wait_queue_head_t reserved_req_waitq;
508 
509 	/** Connection established, cleared on umount, connection
510 	    abort and device release */
511 	unsigned connected;
512 
513 	/** Connection failed (version mismatch).  Cannot race with
514 	    setting other bitfields since it is only set once in INIT
515 	    reply, before any other request, and never cleared */
516 	unsigned conn_error:1;
517 
518 	/** Connection successful.  Only set in INIT */
519 	unsigned conn_init:1;
520 
521 	/** Do readpages asynchronously?  Only set in INIT */
522 	unsigned async_read:1;
523 
524 	/** Do not send separate SETATTR request before open(O_TRUNC)  */
525 	unsigned atomic_o_trunc:1;
526 
527 	/** Filesystem supports NFS exporting.  Only set in INIT */
528 	unsigned export_support:1;
529 
530 	/** Set if bdi is valid */
531 	unsigned bdi_initialized:1;
532 
533 	/** write-back cache policy (default is write-through) */
534 	unsigned writeback_cache:1;
535 
536 	/** allow parallel lookups and readdir (default is serialized) */
537 	unsigned parallel_dirops:1;
538 
539 	/** handle fs handles killing suid/sgid/cap on write/chown/trunc */
540 	unsigned handle_killpriv:1;
541 
542 	/*
543 	 * The following bitfields are only for optimization purposes
544 	 * and hence races in setting them will not cause malfunction
545 	 */
546 
547 	/** Is open/release not implemented by fs? */
548 	unsigned no_open:1;
549 
550 	/** Is fsync not implemented by fs? */
551 	unsigned no_fsync:1;
552 
553 	/** Is fsyncdir not implemented by fs? */
554 	unsigned no_fsyncdir:1;
555 
556 	/** Is flush not implemented by fs? */
557 	unsigned no_flush:1;
558 
559 	/** Is setxattr not implemented by fs? */
560 	unsigned no_setxattr:1;
561 
562 	/** Is getxattr not implemented by fs? */
563 	unsigned no_getxattr:1;
564 
565 	/** Is listxattr not implemented by fs? */
566 	unsigned no_listxattr:1;
567 
568 	/** Is removexattr not implemented by fs? */
569 	unsigned no_removexattr:1;
570 
571 	/** Are posix file locking primitives not implemented by fs? */
572 	unsigned no_lock:1;
573 
574 	/** Is access not implemented by fs? */
575 	unsigned no_access:1;
576 
577 	/** Is create not implemented by fs? */
578 	unsigned no_create:1;
579 
580 	/** Is interrupt not implemented by fs? */
581 	unsigned no_interrupt:1;
582 
583 	/** Is bmap not implemented by fs? */
584 	unsigned no_bmap:1;
585 
586 	/** Is poll not implemented by fs? */
587 	unsigned no_poll:1;
588 
589 	/** Do multi-page cached writes */
590 	unsigned big_writes:1;
591 
592 	/** Don't apply umask to creation modes */
593 	unsigned dont_mask:1;
594 
595 	/** Are BSD file locking primitives not implemented by fs? */
596 	unsigned no_flock:1;
597 
598 	/** Is fallocate not implemented by fs? */
599 	unsigned no_fallocate:1;
600 
601 	/** Is rename with flags implemented by fs? */
602 	unsigned no_rename2:1;
603 
604 	/** Use enhanced/automatic page cache invalidation. */
605 	unsigned auto_inval_data:1;
606 
607 	/** Does the filesystem support readdirplus? */
608 	unsigned do_readdirplus:1;
609 
610 	/** Does the filesystem want adaptive readdirplus? */
611 	unsigned readdirplus_auto:1;
612 
613 	/** Does the filesystem support asynchronous direct-IO submission? */
614 	unsigned async_dio:1;
615 
616 	/** Is lseek not implemented by fs? */
617 	unsigned no_lseek:1;
618 
619 	/** Does the filesystem support posix acls? */
620 	unsigned posix_acl:1;
621 
622 	/** Check permissions based on the file mode or not? */
623 	unsigned default_permissions:1;
624 
625 	/** Allow other than the mounter user to access the filesystem ? */
626 	unsigned allow_other:1;
627 
628 	/** The number of requests waiting for completion */
629 	atomic_t num_waiting;
630 
631 	/** Negotiated minor version */
632 	unsigned minor;
633 
634 	/** Backing dev info */
635 	struct backing_dev_info bdi;
636 
637 	/** Entry on the fuse_conn_list */
638 	struct list_head entry;
639 
640 	/** Device ID from super block */
641 	dev_t dev;
642 
643 	/** Dentries in the control filesystem */
644 	struct dentry *ctl_dentry[FUSE_CTL_NUM_DENTRIES];
645 
646 	/** number of dentries used in the above array */
647 	int ctl_ndents;
648 
649 	/** Key for lock owner ID scrambling */
650 	u32 scramble_key[4];
651 
652 	/** Reserved request for the DESTROY message */
653 	struct fuse_req *destroy_req;
654 
655 	/** Version counter for attribute changes */
656 	u64 attr_version;
657 
658 	/** Called on final put */
659 	void (*release)(struct fuse_conn *);
660 
661 	/** Super block for this connection. */
662 	struct super_block *sb;
663 
664 	/** Read/write semaphore to hold when accessing sb. */
665 	struct rw_semaphore killsb;
666 
667 	/** List of device instances belonging to this connection */
668 	struct list_head devices;
669 };
670 
671 static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb)
672 {
673 	return sb->s_fs_info;
674 }
675 
676 static inline struct fuse_conn *get_fuse_conn(struct inode *inode)
677 {
678 	return get_fuse_conn_super(inode->i_sb);
679 }
680 
681 static inline struct fuse_inode *get_fuse_inode(struct inode *inode)
682 {
683 	return container_of(inode, struct fuse_inode, inode);
684 }
685 
686 static inline u64 get_node_id(struct inode *inode)
687 {
688 	return get_fuse_inode(inode)->nodeid;
689 }
690 
691 /** Device operations */
692 extern const struct file_operations fuse_dev_operations;
693 
694 extern const struct dentry_operations fuse_dentry_operations;
695 
696 /**
697  * Inode to nodeid comparison.
698  */
699 int fuse_inode_eq(struct inode *inode, void *_nodeidp);
700 
701 /**
702  * Get a filled in inode
703  */
704 struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
705 			int generation, struct fuse_attr *attr,
706 			u64 attr_valid, u64 attr_version);
707 
708 int fuse_lookup_name(struct super_block *sb, u64 nodeid, const struct qstr *name,
709 		     struct fuse_entry_out *outarg, struct inode **inode);
710 
711 /**
712  * Send FORGET command
713  */
714 void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget,
715 		       u64 nodeid, u64 nlookup);
716 
717 struct fuse_forget_link *fuse_alloc_forget(void);
718 
719 /* Used by READDIRPLUS */
720 void fuse_force_forget(struct file *file, u64 nodeid);
721 
722 /**
723  * Initialize READ or READDIR request
724  */
725 void fuse_read_fill(struct fuse_req *req, struct file *file,
726 		    loff_t pos, size_t count, int opcode);
727 
728 /**
729  * Send OPEN or OPENDIR request
730  */
731 int fuse_open_common(struct inode *inode, struct file *file, bool isdir);
732 
733 struct fuse_file *fuse_file_alloc(struct fuse_conn *fc);
734 struct fuse_file *fuse_file_get(struct fuse_file *ff);
735 void fuse_file_free(struct fuse_file *ff);
736 void fuse_finish_open(struct inode *inode, struct file *file);
737 
738 void fuse_sync_release(struct fuse_file *ff, int flags);
739 
740 /**
741  * Send RELEASE or RELEASEDIR request
742  */
743 void fuse_release_common(struct file *file, int opcode);
744 
745 /**
746  * Send FSYNC or FSYNCDIR request
747  */
748 int fuse_fsync_common(struct file *file, loff_t start, loff_t end,
749 		      int datasync, int isdir);
750 
751 /**
752  * Notify poll wakeup
753  */
754 int fuse_notify_poll_wakeup(struct fuse_conn *fc,
755 			    struct fuse_notify_poll_wakeup_out *outarg);
756 
757 /**
758  * Initialize file operations on a regular file
759  */
760 void fuse_init_file_inode(struct inode *inode);
761 
762 /**
763  * Initialize inode operations on regular files and special files
764  */
765 void fuse_init_common(struct inode *inode);
766 
767 /**
768  * Initialize inode and file operations on a directory
769  */
770 void fuse_init_dir(struct inode *inode);
771 
772 /**
773  * Initialize inode operations on a symlink
774  */
775 void fuse_init_symlink(struct inode *inode);
776 
777 /**
778  * Change attributes of an inode
779  */
780 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
781 			    u64 attr_valid, u64 attr_version);
782 
783 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
784 				   u64 attr_valid);
785 
786 /**
787  * Initialize the client device
788  */
789 int fuse_dev_init(void);
790 
791 /**
792  * Cleanup the client device
793  */
794 void fuse_dev_cleanup(void);
795 
796 int fuse_ctl_init(void);
797 void __exit fuse_ctl_cleanup(void);
798 
799 /**
800  * Allocate a request
801  */
802 struct fuse_req *fuse_request_alloc(unsigned npages);
803 
804 struct fuse_req *fuse_request_alloc_nofs(unsigned npages);
805 
806 /**
807  * Free a request
808  */
809 void fuse_request_free(struct fuse_req *req);
810 
811 /**
812  * Get a request, may fail with -ENOMEM,
813  * caller should specify # elements in req->pages[] explicitly
814  */
815 struct fuse_req *fuse_get_req(struct fuse_conn *fc, unsigned npages);
816 struct fuse_req *fuse_get_req_for_background(struct fuse_conn *fc,
817 					     unsigned npages);
818 
819 /*
820  * Increment reference count on request
821  */
822 void __fuse_get_request(struct fuse_req *req);
823 
824 /**
825  * Gets a requests for a file operation, always succeeds
826  */
827 struct fuse_req *fuse_get_req_nofail_nopages(struct fuse_conn *fc,
828 					     struct file *file);
829 
830 /**
831  * Decrement reference count of a request.  If count goes to zero free
832  * the request.
833  */
834 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req);
835 
836 /**
837  * Send a request (synchronous)
838  */
839 void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req);
840 
841 /**
842  * Simple request sending that does request allocation and freeing
843  */
844 ssize_t fuse_simple_request(struct fuse_conn *fc, struct fuse_args *args);
845 
846 /**
847  * Send a request in the background
848  */
849 void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req);
850 
851 void fuse_request_send_background_locked(struct fuse_conn *fc,
852 					 struct fuse_req *req);
853 
854 /* Abort all requests */
855 void fuse_abort_conn(struct fuse_conn *fc);
856 
857 /**
858  * Invalidate inode attributes
859  */
860 void fuse_invalidate_attr(struct inode *inode);
861 
862 void fuse_invalidate_entry_cache(struct dentry *entry);
863 
864 void fuse_invalidate_atime(struct inode *inode);
865 
866 /**
867  * Acquire reference to fuse_conn
868  */
869 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc);
870 
871 /**
872  * Initialize fuse_conn
873  */
874 void fuse_conn_init(struct fuse_conn *fc);
875 
876 /**
877  * Release reference to fuse_conn
878  */
879 void fuse_conn_put(struct fuse_conn *fc);
880 
881 struct fuse_dev *fuse_dev_alloc(struct fuse_conn *fc);
882 void fuse_dev_free(struct fuse_dev *fud);
883 
884 /**
885  * Add connection to control filesystem
886  */
887 int fuse_ctl_add_conn(struct fuse_conn *fc);
888 
889 /**
890  * Remove connection from control filesystem
891  */
892 void fuse_ctl_remove_conn(struct fuse_conn *fc);
893 
894 /**
895  * Is file type valid?
896  */
897 int fuse_valid_type(int m);
898 
899 /**
900  * Is current process allowed to perform filesystem operation?
901  */
902 int fuse_allow_current_process(struct fuse_conn *fc);
903 
904 u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id);
905 
906 void fuse_update_ctime(struct inode *inode);
907 
908 int fuse_update_attributes(struct inode *inode, struct kstat *stat,
909 			   struct file *file, bool *refreshed);
910 
911 void fuse_flush_writepages(struct inode *inode);
912 
913 void fuse_set_nowrite(struct inode *inode);
914 void fuse_release_nowrite(struct inode *inode);
915 
916 u64 fuse_get_attr_version(struct fuse_conn *fc);
917 
918 /**
919  * File-system tells the kernel to invalidate cache for the given node id.
920  */
921 int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid,
922 			     loff_t offset, loff_t len);
923 
924 /**
925  * File-system tells the kernel to invalidate parent attributes and
926  * the dentry matching parent/name.
927  *
928  * If the child_nodeid is non-zero and:
929  *    - matches the inode number for the dentry matching parent/name,
930  *    - is not a mount point
931  *    - is a file or oan empty directory
932  * then the dentry is unhashed (d_delete()).
933  */
934 int fuse_reverse_inval_entry(struct super_block *sb, u64 parent_nodeid,
935 			     u64 child_nodeid, struct qstr *name);
936 
937 int fuse_do_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
938 		 bool isdir);
939 
940 /**
941  * fuse_direct_io() flags
942  */
943 
944 /** If set, it is WRITE; otherwise - READ */
945 #define FUSE_DIO_WRITE (1 << 0)
946 
947 /** CUSE pass fuse_direct_io() a file which f_mapping->host is not from FUSE */
948 #define FUSE_DIO_CUSE  (1 << 1)
949 
950 ssize_t fuse_direct_io(struct fuse_io_priv *io, struct iov_iter *iter,
951 		       loff_t *ppos, int flags);
952 long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
953 		   unsigned int flags);
954 long fuse_ioctl_common(struct file *file, unsigned int cmd,
955 		       unsigned long arg, unsigned int flags);
956 unsigned fuse_file_poll(struct file *file, poll_table *wait);
957 int fuse_dev_release(struct inode *inode, struct file *file);
958 
959 bool fuse_write_update_size(struct inode *inode, loff_t pos);
960 
961 int fuse_flush_times(struct inode *inode, struct fuse_file *ff);
962 int fuse_write_inode(struct inode *inode, struct writeback_control *wbc);
963 
964 int fuse_do_setattr(struct dentry *dentry, struct iattr *attr,
965 		    struct file *file);
966 
967 void fuse_set_initialized(struct fuse_conn *fc);
968 
969 void fuse_unlock_inode(struct inode *inode);
970 void fuse_lock_inode(struct inode *inode);
971 
972 int fuse_setxattr(struct inode *inode, const char *name, const void *value,
973 		  size_t size, int flags);
974 ssize_t fuse_getxattr(struct inode *inode, const char *name, void *value,
975 		      size_t size);
976 ssize_t fuse_listxattr(struct dentry *entry, char *list, size_t size);
977 int fuse_removexattr(struct inode *inode, const char *name);
978 extern const struct xattr_handler *fuse_xattr_handlers[];
979 extern const struct xattr_handler *fuse_acl_xattr_handlers[];
980 
981 struct posix_acl;
982 struct posix_acl *fuse_get_acl(struct inode *inode, int type);
983 int fuse_set_acl(struct inode *inode, struct posix_acl *acl, int type);
984 
985 #endif /* _FS_FUSE_I_H */
986