xref: /openbmc/linux/fs/fuse/fuse_i.h (revision d2ba09c1)
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 completion *done;
256 	bool blocking;
257 };
258 
259 #define FUSE_IO_PRIV_SYNC(i) \
260 {					\
261 	.refcnt = KREF_INIT(1),		\
262 	.async = 0,			\
263 	.iocb = i,			\
264 }
265 
266 /**
267  * Request flags
268  *
269  * FR_ISREPLY:		set if the request has reply
270  * FR_FORCE:		force sending of the request even if interrupted
271  * FR_BACKGROUND:	request is sent in the background
272  * FR_WAITING:		request is counted as "waiting"
273  * FR_ABORTED:		the request was aborted
274  * FR_INTERRUPTED:	the request has been interrupted
275  * FR_LOCKED:		data is being copied to/from the request
276  * FR_PENDING:		request is not yet in userspace
277  * FR_SENT:		request is in userspace, waiting for an answer
278  * FR_FINISHED:		request is finished
279  * FR_PRIVATE:		request is on private list
280  */
281 enum fuse_req_flag {
282 	FR_ISREPLY,
283 	FR_FORCE,
284 	FR_BACKGROUND,
285 	FR_WAITING,
286 	FR_ABORTED,
287 	FR_INTERRUPTED,
288 	FR_LOCKED,
289 	FR_PENDING,
290 	FR_SENT,
291 	FR_FINISHED,
292 	FR_PRIVATE,
293 };
294 
295 /**
296  * A request to the client
297  *
298  * .waitq.lock protects the following fields:
299  *   - FR_ABORTED
300  *   - FR_LOCKED (may also be modified under fc->lock, tested under both)
301  */
302 struct fuse_req {
303 	/** This can be on either pending processing or io lists in
304 	    fuse_conn */
305 	struct list_head list;
306 
307 	/** Entry on the interrupts list  */
308 	struct list_head intr_entry;
309 
310 	/** refcount */
311 	refcount_t count;
312 
313 	/** Unique ID for the interrupt request */
314 	u64 intr_unique;
315 
316 	/* Request flags, updated with test/set/clear_bit() */
317 	unsigned long flags;
318 
319 	/** The request input */
320 	struct fuse_in in;
321 
322 	/** The request output */
323 	struct fuse_out out;
324 
325 	/** Used to wake up the task waiting for completion of request*/
326 	wait_queue_head_t waitq;
327 
328 	/** Data for asynchronous requests */
329 	union {
330 		struct {
331 			struct fuse_release_in in;
332 			struct inode *inode;
333 		} release;
334 		struct fuse_init_in init_in;
335 		struct fuse_init_out init_out;
336 		struct cuse_init_in cuse_init_in;
337 		struct {
338 			struct fuse_read_in in;
339 			u64 attr_ver;
340 		} read;
341 		struct {
342 			struct fuse_write_in in;
343 			struct fuse_write_out out;
344 			struct fuse_req *next;
345 		} write;
346 		struct fuse_notify_retrieve_in retrieve_in;
347 	} misc;
348 
349 	/** page vector */
350 	struct page **pages;
351 
352 	/** page-descriptor vector */
353 	struct fuse_page_desc *page_descs;
354 
355 	/** size of the 'pages' array */
356 	unsigned max_pages;
357 
358 	/** inline page vector */
359 	struct page *inline_pages[FUSE_REQ_INLINE_PAGES];
360 
361 	/** inline page-descriptor vector */
362 	struct fuse_page_desc inline_page_descs[FUSE_REQ_INLINE_PAGES];
363 
364 	/** number of pages in vector */
365 	unsigned num_pages;
366 
367 	/** File used in the request (or NULL) */
368 	struct fuse_file *ff;
369 
370 	/** Inode used in the request or NULL */
371 	struct inode *inode;
372 
373 	/** AIO control block */
374 	struct fuse_io_priv *io;
375 
376 	/** Link on fi->writepages */
377 	struct list_head writepages_entry;
378 
379 	/** Request completion callback */
380 	void (*end)(struct fuse_conn *, struct fuse_req *);
381 
382 	/** Request is stolen from fuse_file->reserved_req */
383 	struct file *stolen_file;
384 };
385 
386 struct fuse_iqueue {
387 	/** Connection established */
388 	unsigned connected;
389 
390 	/** Readers of the connection are waiting on this */
391 	wait_queue_head_t waitq;
392 
393 	/** The next unique request id */
394 	u64 reqctr;
395 
396 	/** The list of pending requests */
397 	struct list_head pending;
398 
399 	/** Pending interrupts */
400 	struct list_head interrupts;
401 
402 	/** Queue of pending forgets */
403 	struct fuse_forget_link forget_list_head;
404 	struct fuse_forget_link *forget_list_tail;
405 
406 	/** Batching of FORGET requests (positive indicates FORGET batch) */
407 	int forget_batch;
408 
409 	/** O_ASYNC requests */
410 	struct fasync_struct *fasync;
411 };
412 
413 struct fuse_pqueue {
414 	/** Connection established */
415 	unsigned connected;
416 
417 	/** Lock protecting accessess to  members of this structure */
418 	spinlock_t lock;
419 
420 	/** The list of requests being processed */
421 	struct list_head processing;
422 
423 	/** The list of requests under I/O */
424 	struct list_head io;
425 };
426 
427 /**
428  * Fuse device instance
429  */
430 struct fuse_dev {
431 	/** Fuse connection for this device */
432 	struct fuse_conn *fc;
433 
434 	/** Processing queue */
435 	struct fuse_pqueue pq;
436 
437 	/** list entry on fc->devices */
438 	struct list_head entry;
439 };
440 
441 /**
442  * A Fuse connection.
443  *
444  * This structure is created, when the filesystem is mounted, and is
445  * destroyed, when the client device is closed and the filesystem is
446  * unmounted.
447  */
448 struct fuse_conn {
449 	/** Lock protecting accessess to  members of this structure */
450 	spinlock_t lock;
451 
452 	/** Refcount */
453 	refcount_t count;
454 
455 	/** Number of fuse_dev's */
456 	atomic_t dev_count;
457 
458 	struct rcu_head rcu;
459 
460 	/** The user id for this mount */
461 	kuid_t user_id;
462 
463 	/** The group id for this mount */
464 	kgid_t group_id;
465 
466 	/** The pid namespace for this mount */
467 	struct pid_namespace *pid_ns;
468 
469 	/** Maximum read size */
470 	unsigned max_read;
471 
472 	/** Maximum write size */
473 	unsigned max_write;
474 
475 	/** Input queue */
476 	struct fuse_iqueue iq;
477 
478 	/** The next unique kernel file handle */
479 	u64 khctr;
480 
481 	/** rbtree of fuse_files waiting for poll events indexed by ph */
482 	struct rb_root polled_files;
483 
484 	/** Maximum number of outstanding background requests */
485 	unsigned max_background;
486 
487 	/** Number of background requests at which congestion starts */
488 	unsigned congestion_threshold;
489 
490 	/** Number of requests currently in the background */
491 	unsigned num_background;
492 
493 	/** Number of background requests currently queued for userspace */
494 	unsigned active_background;
495 
496 	/** The list of background requests set aside for later queuing */
497 	struct list_head bg_queue;
498 
499 	/** Flag indicating that INIT reply has been received. Allocating
500 	 * any fuse request will be suspended until the flag is set */
501 	int initialized;
502 
503 	/** Flag indicating if connection is blocked.  This will be
504 	    the case before the INIT reply is received, and if there
505 	    are too many outstading backgrounds requests */
506 	int blocked;
507 
508 	/** waitq for blocked connection */
509 	wait_queue_head_t blocked_waitq;
510 
511 	/** waitq for reserved requests */
512 	wait_queue_head_t reserved_req_waitq;
513 
514 	/** Connection established, cleared on umount, connection
515 	    abort and device release */
516 	unsigned connected;
517 
518 	/** Connection failed (version mismatch).  Cannot race with
519 	    setting other bitfields since it is only set once in INIT
520 	    reply, before any other request, and never cleared */
521 	unsigned conn_error:1;
522 
523 	/** Connection successful.  Only set in INIT */
524 	unsigned conn_init:1;
525 
526 	/** Do readpages asynchronously?  Only set in INIT */
527 	unsigned async_read:1;
528 
529 	/** Do not send separate SETATTR request before open(O_TRUNC)  */
530 	unsigned atomic_o_trunc:1;
531 
532 	/** Filesystem supports NFS exporting.  Only set in INIT */
533 	unsigned export_support:1;
534 
535 	/** write-back cache policy (default is write-through) */
536 	unsigned writeback_cache:1;
537 
538 	/** allow parallel lookups and readdir (default is serialized) */
539 	unsigned parallel_dirops:1;
540 
541 	/** handle fs handles killing suid/sgid/cap on write/chown/trunc */
542 	unsigned handle_killpriv:1;
543 
544 	/*
545 	 * The following bitfields are only for optimization purposes
546 	 * and hence races in setting them will not cause malfunction
547 	 */
548 
549 	/** Is open/release not implemented by fs? */
550 	unsigned no_open:1;
551 
552 	/** Is fsync not implemented by fs? */
553 	unsigned no_fsync:1;
554 
555 	/** Is fsyncdir not implemented by fs? */
556 	unsigned no_fsyncdir:1;
557 
558 	/** Is flush not implemented by fs? */
559 	unsigned no_flush:1;
560 
561 	/** Is setxattr not implemented by fs? */
562 	unsigned no_setxattr:1;
563 
564 	/** Is getxattr not implemented by fs? */
565 	unsigned no_getxattr:1;
566 
567 	/** Is listxattr not implemented by fs? */
568 	unsigned no_listxattr:1;
569 
570 	/** Is removexattr not implemented by fs? */
571 	unsigned no_removexattr:1;
572 
573 	/** Are posix file locking primitives not implemented by fs? */
574 	unsigned no_lock:1;
575 
576 	/** Is access not implemented by fs? */
577 	unsigned no_access:1;
578 
579 	/** Is create not implemented by fs? */
580 	unsigned no_create:1;
581 
582 	/** Is interrupt not implemented by fs? */
583 	unsigned no_interrupt:1;
584 
585 	/** Is bmap not implemented by fs? */
586 	unsigned no_bmap:1;
587 
588 	/** Is poll not implemented by fs? */
589 	unsigned no_poll:1;
590 
591 	/** Do multi-page cached writes */
592 	unsigned big_writes:1;
593 
594 	/** Don't apply umask to creation modes */
595 	unsigned dont_mask:1;
596 
597 	/** Are BSD file locking primitives not implemented by fs? */
598 	unsigned no_flock:1;
599 
600 	/** Is fallocate not implemented by fs? */
601 	unsigned no_fallocate:1;
602 
603 	/** Is rename with flags implemented by fs? */
604 	unsigned no_rename2:1;
605 
606 	/** Use enhanced/automatic page cache invalidation. */
607 	unsigned auto_inval_data:1;
608 
609 	/** Does the filesystem support readdirplus? */
610 	unsigned do_readdirplus:1;
611 
612 	/** Does the filesystem want adaptive readdirplus? */
613 	unsigned readdirplus_auto:1;
614 
615 	/** Does the filesystem support asynchronous direct-IO submission? */
616 	unsigned async_dio:1;
617 
618 	/** Is lseek not implemented by fs? */
619 	unsigned no_lseek:1;
620 
621 	/** Does the filesystem support posix acls? */
622 	unsigned posix_acl:1;
623 
624 	/** Check permissions based on the file mode or not? */
625 	unsigned default_permissions:1;
626 
627 	/** Allow other than the mounter user to access the filesystem ? */
628 	unsigned allow_other:1;
629 
630 	/** The number of requests waiting for completion */
631 	atomic_t num_waiting;
632 
633 	/** Negotiated minor version */
634 	unsigned minor;
635 
636 	/** Entry on the fuse_conn_list */
637 	struct list_head entry;
638 
639 	/** Device ID from super block */
640 	dev_t dev;
641 
642 	/** Dentries in the control filesystem */
643 	struct dentry *ctl_dentry[FUSE_CTL_NUM_DENTRIES];
644 
645 	/** number of dentries used in the above array */
646 	int ctl_ndents;
647 
648 	/** Key for lock owner ID scrambling */
649 	u32 scramble_key[4];
650 
651 	/** Reserved request for the DESTROY message */
652 	struct fuse_req *destroy_req;
653 
654 	/** Version counter for attribute changes */
655 	u64 attr_version;
656 
657 	/** Called on final put */
658 	void (*release)(struct fuse_conn *);
659 
660 	/** Super block for this connection. */
661 	struct super_block *sb;
662 
663 	/** Read/write semaphore to hold when accessing sb. */
664 	struct rw_semaphore killsb;
665 
666 	/** List of device instances belonging to this connection */
667 	struct list_head devices;
668 };
669 
670 static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb)
671 {
672 	return sb->s_fs_info;
673 }
674 
675 static inline struct fuse_conn *get_fuse_conn(struct inode *inode)
676 {
677 	return get_fuse_conn_super(inode->i_sb);
678 }
679 
680 static inline struct fuse_inode *get_fuse_inode(struct inode *inode)
681 {
682 	return container_of(inode, struct fuse_inode, inode);
683 }
684 
685 static inline u64 get_node_id(struct inode *inode)
686 {
687 	return get_fuse_inode(inode)->nodeid;
688 }
689 
690 /** Device operations */
691 extern const struct file_operations fuse_dev_operations;
692 
693 extern const struct dentry_operations fuse_dentry_operations;
694 extern const struct dentry_operations fuse_root_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 void fuse_file_free(struct fuse_file *ff);
735 void fuse_finish_open(struct inode *inode, struct file *file);
736 
737 void fuse_sync_release(struct fuse_file *ff, int flags);
738 
739 /**
740  * Send RELEASE or RELEASEDIR request
741  */
742 void fuse_release_common(struct file *file, int opcode);
743 
744 /**
745  * Send FSYNC or FSYNCDIR request
746  */
747 int fuse_fsync_common(struct file *file, loff_t start, loff_t end,
748 		      int datasync, int isdir);
749 
750 /**
751  * Notify poll wakeup
752  */
753 int fuse_notify_poll_wakeup(struct fuse_conn *fc,
754 			    struct fuse_notify_poll_wakeup_out *outarg);
755 
756 /**
757  * Initialize file operations on a regular file
758  */
759 void fuse_init_file_inode(struct inode *inode);
760 
761 /**
762  * Initialize inode operations on regular files and special files
763  */
764 void fuse_init_common(struct inode *inode);
765 
766 /**
767  * Initialize inode and file operations on a directory
768  */
769 void fuse_init_dir(struct inode *inode);
770 
771 /**
772  * Initialize inode operations on a symlink
773  */
774 void fuse_init_symlink(struct inode *inode);
775 
776 /**
777  * Change attributes of an inode
778  */
779 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
780 			    u64 attr_valid, u64 attr_version);
781 
782 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
783 				   u64 attr_valid);
784 
785 /**
786  * Initialize the client device
787  */
788 int fuse_dev_init(void);
789 
790 /**
791  * Cleanup the client device
792  */
793 void fuse_dev_cleanup(void);
794 
795 int fuse_ctl_init(void);
796 void __exit fuse_ctl_cleanup(void);
797 
798 /**
799  * Allocate a request
800  */
801 struct fuse_req *fuse_request_alloc(unsigned npages);
802 
803 struct fuse_req *fuse_request_alloc_nofs(unsigned npages);
804 
805 /**
806  * Free a request
807  */
808 void fuse_request_free(struct fuse_req *req);
809 
810 /**
811  * Get a request, may fail with -ENOMEM,
812  * caller should specify # elements in req->pages[] explicitly
813  */
814 struct fuse_req *fuse_get_req(struct fuse_conn *fc, unsigned npages);
815 struct fuse_req *fuse_get_req_for_background(struct fuse_conn *fc,
816 					     unsigned npages);
817 
818 /*
819  * Increment reference count on request
820  */
821 void __fuse_get_request(struct fuse_req *req);
822 
823 /**
824  * Gets a requests for a file operation, always succeeds
825  */
826 struct fuse_req *fuse_get_req_nofail_nopages(struct fuse_conn *fc,
827 					     struct file *file);
828 
829 /**
830  * Decrement reference count of a request.  If count goes to zero free
831  * the request.
832  */
833 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req);
834 
835 /**
836  * Send a request (synchronous)
837  */
838 void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req);
839 
840 /**
841  * Simple request sending that does request allocation and freeing
842  */
843 ssize_t fuse_simple_request(struct fuse_conn *fc, struct fuse_args *args);
844 
845 /**
846  * Send a request in the background
847  */
848 void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req);
849 
850 void fuse_request_send_background_locked(struct fuse_conn *fc,
851 					 struct fuse_req *req);
852 
853 /* Abort all requests */
854 void fuse_abort_conn(struct fuse_conn *fc);
855 
856 /**
857  * Invalidate inode attributes
858  */
859 void fuse_invalidate_attr(struct inode *inode);
860 
861 void fuse_invalidate_entry_cache(struct dentry *entry);
862 
863 void fuse_invalidate_atime(struct inode *inode);
864 
865 /**
866  * Acquire reference to fuse_conn
867  */
868 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc);
869 
870 /**
871  * Initialize fuse_conn
872  */
873 void fuse_conn_init(struct fuse_conn *fc);
874 
875 /**
876  * Release reference to fuse_conn
877  */
878 void fuse_conn_put(struct fuse_conn *fc);
879 
880 struct fuse_dev *fuse_dev_alloc(struct fuse_conn *fc);
881 void fuse_dev_free(struct fuse_dev *fud);
882 
883 /**
884  * Add connection to control filesystem
885  */
886 int fuse_ctl_add_conn(struct fuse_conn *fc);
887 
888 /**
889  * Remove connection from control filesystem
890  */
891 void fuse_ctl_remove_conn(struct fuse_conn *fc);
892 
893 /**
894  * Is file type valid?
895  */
896 int fuse_valid_type(int m);
897 
898 /**
899  * Is current process allowed to perform filesystem operation?
900  */
901 int fuse_allow_current_process(struct fuse_conn *fc);
902 
903 u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id);
904 
905 void fuse_update_ctime(struct inode *inode);
906 
907 int fuse_update_attributes(struct inode *inode, struct file *file);
908 
909 void fuse_flush_writepages(struct inode *inode);
910 
911 void fuse_set_nowrite(struct inode *inode);
912 void fuse_release_nowrite(struct inode *inode);
913 
914 u64 fuse_get_attr_version(struct fuse_conn *fc);
915 
916 /**
917  * File-system tells the kernel to invalidate cache for the given node id.
918  */
919 int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid,
920 			     loff_t offset, loff_t len);
921 
922 /**
923  * File-system tells the kernel to invalidate parent attributes and
924  * the dentry matching parent/name.
925  *
926  * If the child_nodeid is non-zero and:
927  *    - matches the inode number for the dentry matching parent/name,
928  *    - is not a mount point
929  *    - is a file or oan empty directory
930  * then the dentry is unhashed (d_delete()).
931  */
932 int fuse_reverse_inval_entry(struct super_block *sb, u64 parent_nodeid,
933 			     u64 child_nodeid, struct qstr *name);
934 
935 int fuse_do_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
936 		 bool isdir);
937 
938 /**
939  * fuse_direct_io() flags
940  */
941 
942 /** If set, it is WRITE; otherwise - READ */
943 #define FUSE_DIO_WRITE (1 << 0)
944 
945 /** CUSE pass fuse_direct_io() a file which f_mapping->host is not from FUSE */
946 #define FUSE_DIO_CUSE  (1 << 1)
947 
948 ssize_t fuse_direct_io(struct fuse_io_priv *io, struct iov_iter *iter,
949 		       loff_t *ppos, int flags);
950 long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
951 		   unsigned int flags);
952 long fuse_ioctl_common(struct file *file, unsigned int cmd,
953 		       unsigned long arg, unsigned int flags);
954 __poll_t fuse_file_poll(struct file *file, poll_table *wait);
955 int fuse_dev_release(struct inode *inode, struct file *file);
956 
957 bool fuse_write_update_size(struct inode *inode, loff_t pos);
958 
959 int fuse_flush_times(struct inode *inode, struct fuse_file *ff);
960 int fuse_write_inode(struct inode *inode, struct writeback_control *wbc);
961 
962 int fuse_do_setattr(struct dentry *dentry, struct iattr *attr,
963 		    struct file *file);
964 
965 void fuse_set_initialized(struct fuse_conn *fc);
966 
967 void fuse_unlock_inode(struct inode *inode);
968 void fuse_lock_inode(struct inode *inode);
969 
970 int fuse_setxattr(struct inode *inode, const char *name, const void *value,
971 		  size_t size, int flags);
972 ssize_t fuse_getxattr(struct inode *inode, const char *name, void *value,
973 		      size_t size);
974 ssize_t fuse_listxattr(struct dentry *entry, char *list, size_t size);
975 int fuse_removexattr(struct inode *inode, const char *name);
976 extern const struct xattr_handler *fuse_xattr_handlers[];
977 extern const struct xattr_handler *fuse_acl_xattr_handlers[];
978 
979 struct posix_acl;
980 struct posix_acl *fuse_get_acl(struct inode *inode, int type);
981 int fuse_set_acl(struct inode *inode, struct posix_acl *acl, int type);
982 
983 #endif /* _FS_FUSE_I_H */
984