xref: /openbmc/linux/fs/fuse/fuse_i.h (revision c8dbaa22)
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 #include <linux/pid_namespace.h>
28 #include <linux/refcount.h>
29 
30 /** Max number of pages that can be used in a single read request */
31 #define FUSE_MAX_PAGES_PER_REQ 32
32 
33 /** Bias for fi->writectr, meaning new writepages must not be sent */
34 #define FUSE_NOWRITE INT_MIN
35 
36 /** It could be as large as PATH_MAX, but would that have any uses? */
37 #define FUSE_NAME_MAX 1024
38 
39 /** Number of dentries for each connection in the control filesystem */
40 #define FUSE_CTL_NUM_DENTRIES 5
41 
42 /** Number of page pointers embedded in fuse_req */
43 #define FUSE_REQ_INLINE_PAGES 1
44 
45 /** List of active connections */
46 extern struct list_head fuse_conn_list;
47 
48 /** Global mutex protecting fuse_conn_list and the control filesystem */
49 extern struct mutex fuse_mutex;
50 
51 /** Module parameters */
52 extern unsigned max_user_bgreq;
53 extern unsigned max_user_congthresh;
54 
55 /* One forget request */
56 struct fuse_forget_link {
57 	struct fuse_forget_one forget_one;
58 	struct fuse_forget_link *next;
59 };
60 
61 /** FUSE inode */
62 struct fuse_inode {
63 	/** Inode data */
64 	struct inode inode;
65 
66 	/** Unique ID, which identifies the inode between userspace
67 	 * and kernel */
68 	u64 nodeid;
69 
70 	/** Number of lookups on this inode */
71 	u64 nlookup;
72 
73 	/** The request used for sending the FORGET message */
74 	struct fuse_forget_link *forget;
75 
76 	/** Time in jiffies until the file attributes are valid */
77 	u64 i_time;
78 
79 	/** The sticky bit in inode->i_mode may have been removed, so
80 	    preserve the original mode */
81 	umode_t orig_i_mode;
82 
83 	/** 64 bit inode number */
84 	u64 orig_ino;
85 
86 	/** Version of last attribute change */
87 	u64 attr_version;
88 
89 	/** Files usable in writepage.  Protected by fc->lock */
90 	struct list_head write_files;
91 
92 	/** Writepages pending on truncate or fsync */
93 	struct list_head queued_writes;
94 
95 	/** Number of sent writes, a negative bias (FUSE_NOWRITE)
96 	 * means more writes are blocked */
97 	int writectr;
98 
99 	/** Waitq for writepage completion */
100 	wait_queue_head_t page_waitq;
101 
102 	/** List of writepage requestst (pending or sent) */
103 	struct list_head writepages;
104 
105 	/** Miscellaneous bits describing inode state */
106 	unsigned long state;
107 
108 	/** Lock for serializing lookup and readdir for back compatibility*/
109 	struct mutex mutex;
110 };
111 
112 /** FUSE inode state bits */
113 enum {
114 	/** Advise readdirplus  */
115 	FUSE_I_ADVISE_RDPLUS,
116 	/** Initialized with readdirplus */
117 	FUSE_I_INIT_RDPLUS,
118 	/** An operation changing file size is in progress  */
119 	FUSE_I_SIZE_UNSTABLE,
120 };
121 
122 struct fuse_conn;
123 
124 /** FUSE specific file data */
125 struct fuse_file {
126 	/** Fuse connection for this file */
127 	struct fuse_conn *fc;
128 
129 	/** Request reserved for flush and release */
130 	struct fuse_req *reserved_req;
131 
132 	/** Kernel file handle guaranteed to be unique */
133 	u64 kh;
134 
135 	/** File handle used by userspace */
136 	u64 fh;
137 
138 	/** Node id of this file */
139 	u64 nodeid;
140 
141 	/** Refcount */
142 	refcount_t count;
143 
144 	/** FOPEN_* flags returned by open */
145 	u32 open_flags;
146 
147 	/** Entry on inode's write_files list */
148 	struct list_head write_entry;
149 
150 	/** RB node to be linked on fuse_conn->polled_files */
151 	struct rb_node polled_node;
152 
153 	/** Wait queue head for poll */
154 	wait_queue_head_t poll_wait;
155 
156 	/** Has flock been performed on this file? */
157 	bool flock:1;
158 };
159 
160 /** One input argument of a request */
161 struct fuse_in_arg {
162 	unsigned size;
163 	const void *value;
164 };
165 
166 /** The request input */
167 struct fuse_in {
168 	/** The request header */
169 	struct fuse_in_header h;
170 
171 	/** True if the data for the last argument is in req->pages */
172 	unsigned argpages:1;
173 
174 	/** Number of arguments */
175 	unsigned numargs;
176 
177 	/** Array of arguments */
178 	struct fuse_in_arg args[3];
179 };
180 
181 /** One output argument of a request */
182 struct fuse_arg {
183 	unsigned size;
184 	void *value;
185 };
186 
187 /** The request output */
188 struct fuse_out {
189 	/** Header returned from userspace */
190 	struct fuse_out_header h;
191 
192 	/*
193 	 * The following bitfields are not changed during the request
194 	 * processing
195 	 */
196 
197 	/** Last argument is variable length (can be shorter than
198 	    arg->size) */
199 	unsigned argvar:1;
200 
201 	/** Last argument is a list of pages to copy data to */
202 	unsigned argpages:1;
203 
204 	/** Zero partially or not copied pages */
205 	unsigned page_zeroing:1;
206 
207 	/** Pages may be replaced with new ones */
208 	unsigned page_replace:1;
209 
210 	/** Number or arguments */
211 	unsigned numargs;
212 
213 	/** Array of arguments */
214 	struct fuse_arg args[2];
215 };
216 
217 /** FUSE page descriptor */
218 struct fuse_page_desc {
219 	unsigned int length;
220 	unsigned int offset;
221 };
222 
223 struct fuse_args {
224 	struct {
225 		struct {
226 			uint32_t opcode;
227 			uint64_t nodeid;
228 		} h;
229 		unsigned numargs;
230 		struct fuse_in_arg args[3];
231 
232 	} in;
233 	struct {
234 		unsigned argvar:1;
235 		unsigned numargs;
236 		struct fuse_arg args[2];
237 	} out;
238 };
239 
240 #define FUSE_ARGS(args) struct fuse_args args = {}
241 
242 /** The request IO state (for asynchronous processing) */
243 struct fuse_io_priv {
244 	struct kref refcnt;
245 	int async;
246 	spinlock_t lock;
247 	unsigned reqs;
248 	ssize_t bytes;
249 	size_t size;
250 	__u64 offset;
251 	bool write;
252 	bool should_dirty;
253 	int err;
254 	struct kiocb *iocb;
255 	struct file *file;
256 	struct completion *done;
257 	bool blocking;
258 };
259 
260 #define FUSE_IO_PRIV_SYNC(f) \
261 {					\
262 	.refcnt = KREF_INIT(1),		\
263 	.async = 0,			\
264 	.file = f,			\
265 }
266 
267 /**
268  * Request flags
269  *
270  * FR_ISREPLY:		set if the request has reply
271  * FR_FORCE:		force sending of the request even if interrupted
272  * FR_BACKGROUND:	request is sent in the background
273  * FR_WAITING:		request is counted as "waiting"
274  * FR_ABORTED:		the request was aborted
275  * FR_INTERRUPTED:	the request has been interrupted
276  * FR_LOCKED:		data is being copied to/from the request
277  * FR_PENDING:		request is not yet in userspace
278  * FR_SENT:		request is in userspace, waiting for an answer
279  * FR_FINISHED:		request is finished
280  * FR_PRIVATE:		request is on private list
281  */
282 enum fuse_req_flag {
283 	FR_ISREPLY,
284 	FR_FORCE,
285 	FR_BACKGROUND,
286 	FR_WAITING,
287 	FR_ABORTED,
288 	FR_INTERRUPTED,
289 	FR_LOCKED,
290 	FR_PENDING,
291 	FR_SENT,
292 	FR_FINISHED,
293 	FR_PRIVATE,
294 };
295 
296 /**
297  * A request to the client
298  *
299  * .waitq.lock protects the following fields:
300  *   - FR_ABORTED
301  *   - FR_LOCKED (may also be modified under fc->lock, tested under both)
302  */
303 struct fuse_req {
304 	/** This can be on either pending processing or io lists in
305 	    fuse_conn */
306 	struct list_head list;
307 
308 	/** Entry on the interrupts list  */
309 	struct list_head intr_entry;
310 
311 	/** refcount */
312 	refcount_t count;
313 
314 	/** Unique ID for the interrupt request */
315 	u64 intr_unique;
316 
317 	/* Request flags, updated with test/set/clear_bit() */
318 	unsigned long flags;
319 
320 	/** The request input */
321 	struct fuse_in in;
322 
323 	/** The request output */
324 	struct fuse_out out;
325 
326 	/** Used to wake up the task waiting for completion of request*/
327 	wait_queue_head_t waitq;
328 
329 	/** Data for asynchronous requests */
330 	union {
331 		struct {
332 			struct fuse_release_in in;
333 			struct inode *inode;
334 		} release;
335 		struct fuse_init_in init_in;
336 		struct fuse_init_out init_out;
337 		struct cuse_init_in cuse_init_in;
338 		struct {
339 			struct fuse_read_in in;
340 			u64 attr_ver;
341 		} read;
342 		struct {
343 			struct fuse_write_in in;
344 			struct fuse_write_out out;
345 			struct fuse_req *next;
346 		} write;
347 		struct fuse_notify_retrieve_in retrieve_in;
348 	} misc;
349 
350 	/** page vector */
351 	struct page **pages;
352 
353 	/** page-descriptor vector */
354 	struct fuse_page_desc *page_descs;
355 
356 	/** size of the 'pages' array */
357 	unsigned max_pages;
358 
359 	/** inline page vector */
360 	struct page *inline_pages[FUSE_REQ_INLINE_PAGES];
361 
362 	/** inline page-descriptor vector */
363 	struct fuse_page_desc inline_page_descs[FUSE_REQ_INLINE_PAGES];
364 
365 	/** number of pages in vector */
366 	unsigned num_pages;
367 
368 	/** File used in the request (or NULL) */
369 	struct fuse_file *ff;
370 
371 	/** Inode used in the request or NULL */
372 	struct inode *inode;
373 
374 	/** AIO control block */
375 	struct fuse_io_priv *io;
376 
377 	/** Link on fi->writepages */
378 	struct list_head writepages_entry;
379 
380 	/** Request completion callback */
381 	void (*end)(struct fuse_conn *, struct fuse_req *);
382 
383 	/** Request is stolen from fuse_file->reserved_req */
384 	struct file *stolen_file;
385 };
386 
387 struct fuse_iqueue {
388 	/** Connection established */
389 	unsigned connected;
390 
391 	/** Readers of the connection are waiting on this */
392 	wait_queue_head_t waitq;
393 
394 	/** The next unique request id */
395 	u64 reqctr;
396 
397 	/** The list of pending requests */
398 	struct list_head pending;
399 
400 	/** Pending interrupts */
401 	struct list_head interrupts;
402 
403 	/** Queue of pending forgets */
404 	struct fuse_forget_link forget_list_head;
405 	struct fuse_forget_link *forget_list_tail;
406 
407 	/** Batching of FORGET requests (positive indicates FORGET batch) */
408 	int forget_batch;
409 
410 	/** O_ASYNC requests */
411 	struct fasync_struct *fasync;
412 };
413 
414 struct fuse_pqueue {
415 	/** Connection established */
416 	unsigned connected;
417 
418 	/** Lock protecting accessess to  members of this structure */
419 	spinlock_t lock;
420 
421 	/** The list of requests being processed */
422 	struct list_head processing;
423 
424 	/** The list of requests under I/O */
425 	struct list_head io;
426 };
427 
428 /**
429  * Fuse device instance
430  */
431 struct fuse_dev {
432 	/** Fuse connection for this device */
433 	struct fuse_conn *fc;
434 
435 	/** Processing queue */
436 	struct fuse_pqueue pq;
437 
438 	/** list entry on fc->devices */
439 	struct list_head entry;
440 };
441 
442 /**
443  * A Fuse connection.
444  *
445  * This structure is created, when the filesystem is mounted, and is
446  * destroyed, when the client device is closed and the filesystem is
447  * unmounted.
448  */
449 struct fuse_conn {
450 	/** Lock protecting accessess to  members of this structure */
451 	spinlock_t lock;
452 
453 	/** Refcount */
454 	refcount_t count;
455 
456 	/** Number of fuse_dev's */
457 	atomic_t dev_count;
458 
459 	struct rcu_head rcu;
460 
461 	/** The user id for this mount */
462 	kuid_t user_id;
463 
464 	/** The group id for this mount */
465 	kgid_t group_id;
466 
467 	/** The pid namespace for this mount */
468 	struct pid_namespace *pid_ns;
469 
470 	/** Maximum read size */
471 	unsigned max_read;
472 
473 	/** Maximum write size */
474 	unsigned max_write;
475 
476 	/** Input queue */
477 	struct fuse_iqueue iq;
478 
479 	/** The next unique kernel file handle */
480 	u64 khctr;
481 
482 	/** rbtree of fuse_files waiting for poll events indexed by ph */
483 	struct rb_root polled_files;
484 
485 	/** Maximum number of outstanding background requests */
486 	unsigned max_background;
487 
488 	/** Number of background requests at which congestion starts */
489 	unsigned congestion_threshold;
490 
491 	/** Number of requests currently in the background */
492 	unsigned num_background;
493 
494 	/** Number of background requests currently queued for userspace */
495 	unsigned active_background;
496 
497 	/** The list of background requests set aside for later queuing */
498 	struct list_head bg_queue;
499 
500 	/** Flag indicating that INIT reply has been received. Allocating
501 	 * any fuse request will be suspended until the flag is set */
502 	int initialized;
503 
504 	/** Flag indicating if connection is blocked.  This will be
505 	    the case before the INIT reply is received, and if there
506 	    are too many outstading backgrounds requests */
507 	int blocked;
508 
509 	/** waitq for blocked connection */
510 	wait_queue_head_t blocked_waitq;
511 
512 	/** waitq for reserved requests */
513 	wait_queue_head_t reserved_req_waitq;
514 
515 	/** Connection established, cleared on umount, connection
516 	    abort and device release */
517 	unsigned connected;
518 
519 	/** Connection failed (version mismatch).  Cannot race with
520 	    setting other bitfields since it is only set once in INIT
521 	    reply, before any other request, and never cleared */
522 	unsigned conn_error:1;
523 
524 	/** Connection successful.  Only set in INIT */
525 	unsigned conn_init:1;
526 
527 	/** Do readpages asynchronously?  Only set in INIT */
528 	unsigned async_read:1;
529 
530 	/** Do not send separate SETATTR request before open(O_TRUNC)  */
531 	unsigned atomic_o_trunc:1;
532 
533 	/** Filesystem supports NFS exporting.  Only set in INIT */
534 	unsigned export_support:1;
535 
536 	/** write-back cache policy (default is write-through) */
537 	unsigned writeback_cache:1;
538 
539 	/** allow parallel lookups and readdir (default is serialized) */
540 	unsigned parallel_dirops:1;
541 
542 	/** handle fs handles killing suid/sgid/cap on write/chown/trunc */
543 	unsigned handle_killpriv:1;
544 
545 	/*
546 	 * The following bitfields are only for optimization purposes
547 	 * and hence races in setting them will not cause malfunction
548 	 */
549 
550 	/** Is open/release not implemented by fs? */
551 	unsigned no_open:1;
552 
553 	/** Is fsync not implemented by fs? */
554 	unsigned no_fsync:1;
555 
556 	/** Is fsyncdir not implemented by fs? */
557 	unsigned no_fsyncdir:1;
558 
559 	/** Is flush not implemented by fs? */
560 	unsigned no_flush:1;
561 
562 	/** Is setxattr not implemented by fs? */
563 	unsigned no_setxattr:1;
564 
565 	/** Is getxattr not implemented by fs? */
566 	unsigned no_getxattr:1;
567 
568 	/** Is listxattr not implemented by fs? */
569 	unsigned no_listxattr:1;
570 
571 	/** Is removexattr not implemented by fs? */
572 	unsigned no_removexattr:1;
573 
574 	/** Are posix file locking primitives not implemented by fs? */
575 	unsigned no_lock:1;
576 
577 	/** Is access not implemented by fs? */
578 	unsigned no_access:1;
579 
580 	/** Is create not implemented by fs? */
581 	unsigned no_create:1;
582 
583 	/** Is interrupt not implemented by fs? */
584 	unsigned no_interrupt:1;
585 
586 	/** Is bmap not implemented by fs? */
587 	unsigned no_bmap:1;
588 
589 	/** Is poll not implemented by fs? */
590 	unsigned no_poll:1;
591 
592 	/** Do multi-page cached writes */
593 	unsigned big_writes:1;
594 
595 	/** Don't apply umask to creation modes */
596 	unsigned dont_mask:1;
597 
598 	/** Are BSD file locking primitives not implemented by fs? */
599 	unsigned no_flock:1;
600 
601 	/** Is fallocate not implemented by fs? */
602 	unsigned no_fallocate:1;
603 
604 	/** Is rename with flags implemented by fs? */
605 	unsigned no_rename2:1;
606 
607 	/** Use enhanced/automatic page cache invalidation. */
608 	unsigned auto_inval_data:1;
609 
610 	/** Does the filesystem support readdirplus? */
611 	unsigned do_readdirplus:1;
612 
613 	/** Does the filesystem want adaptive readdirplus? */
614 	unsigned readdirplus_auto:1;
615 
616 	/** Does the filesystem support asynchronous direct-IO submission? */
617 	unsigned async_dio:1;
618 
619 	/** Is lseek not implemented by fs? */
620 	unsigned no_lseek:1;
621 
622 	/** Does the filesystem support posix acls? */
623 	unsigned posix_acl:1;
624 
625 	/** Check permissions based on the file mode or not? */
626 	unsigned default_permissions:1;
627 
628 	/** Allow other than the mounter user to access the filesystem ? */
629 	unsigned allow_other:1;
630 
631 	/** The number of requests waiting for completion */
632 	atomic_t num_waiting;
633 
634 	/** Negotiated minor version */
635 	unsigned minor;
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 extern const struct dentry_operations fuse_root_dentry_operations;
696 
697 /**
698  * Inode to nodeid comparison.
699  */
700 int fuse_inode_eq(struct inode *inode, void *_nodeidp);
701 
702 /**
703  * Get a filled in inode
704  */
705 struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
706 			int generation, struct fuse_attr *attr,
707 			u64 attr_valid, u64 attr_version);
708 
709 int fuse_lookup_name(struct super_block *sb, u64 nodeid, const struct qstr *name,
710 		     struct fuse_entry_out *outarg, struct inode **inode);
711 
712 /**
713  * Send FORGET command
714  */
715 void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget,
716 		       u64 nodeid, u64 nlookup);
717 
718 struct fuse_forget_link *fuse_alloc_forget(void);
719 
720 /* Used by READDIRPLUS */
721 void fuse_force_forget(struct file *file, u64 nodeid);
722 
723 /**
724  * Initialize READ or READDIR request
725  */
726 void fuse_read_fill(struct fuse_req *req, struct file *file,
727 		    loff_t pos, size_t count, int opcode);
728 
729 /**
730  * Send OPEN or OPENDIR request
731  */
732 int fuse_open_common(struct inode *inode, struct file *file, bool isdir);
733 
734 struct fuse_file *fuse_file_alloc(struct fuse_conn *fc);
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