xref: /linux/fs/fuse/fuse_i.h (revision b68fc09be48edbc47de1a0f3d42ef8adf6c0ac55)
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 #include <linux/user_namespace.h>
30 
31 /** Max number of pages that can be used in a single read request */
32 #define FUSE_MAX_PAGES_PER_REQ 32
33 
34 /** Bias for fi->writectr, meaning new writepages must not be sent */
35 #define FUSE_NOWRITE INT_MIN
36 
37 /** It could be as large as PATH_MAX, but would that have any uses? */
38 #define FUSE_NAME_MAX 1024
39 
40 /** Number of dentries for each connection in the control filesystem */
41 #define FUSE_CTL_NUM_DENTRIES 5
42 
43 /** Number of page pointers embedded in fuse_req */
44 #define FUSE_REQ_INLINE_PAGES 1
45 
46 /** List of active connections */
47 extern struct list_head fuse_conn_list;
48 
49 /** Global mutex protecting fuse_conn_list and the control filesystem */
50 extern struct mutex fuse_mutex;
51 
52 /** Module parameters */
53 extern unsigned max_user_bgreq;
54 extern unsigned max_user_congthresh;
55 
56 /* One forget request */
57 struct fuse_forget_link {
58 	struct fuse_forget_one forget_one;
59 	struct fuse_forget_link *next;
60 };
61 
62 /** FUSE inode */
63 struct fuse_inode {
64 	/** Inode data */
65 	struct inode inode;
66 
67 	/** Unique ID, which identifies the inode between userspace
68 	 * and kernel */
69 	u64 nodeid;
70 
71 	/** Number of lookups on this inode */
72 	u64 nlookup;
73 
74 	/** The request used for sending the FORGET message */
75 	struct fuse_forget_link *forget;
76 
77 	/** Time in jiffies until the file attributes are valid */
78 	u64 i_time;
79 
80 	/** The sticky bit in inode->i_mode may have been removed, so
81 	    preserve the original mode */
82 	umode_t orig_i_mode;
83 
84 	/** 64 bit inode number */
85 	u64 orig_ino;
86 
87 	/** Version of last attribute change */
88 	u64 attr_version;
89 
90 	/** Files usable in writepage.  Protected by fc->lock */
91 	struct list_head write_files;
92 
93 	/** Writepages pending on truncate or fsync */
94 	struct list_head queued_writes;
95 
96 	/** Number of sent writes, a negative bias (FUSE_NOWRITE)
97 	 * means more writes are blocked */
98 	int writectr;
99 
100 	/** Waitq for writepage completion */
101 	wait_queue_head_t page_waitq;
102 
103 	/** List of writepage requestst (pending or sent) */
104 	struct list_head writepages;
105 
106 	/** Miscellaneous bits describing inode state */
107 	unsigned long state;
108 
109 	/** Lock for serializing lookup and readdir for back compatibility*/
110 	struct mutex mutex;
111 };
112 
113 /** FUSE inode state bits */
114 enum {
115 	/** Advise readdirplus  */
116 	FUSE_I_ADVISE_RDPLUS,
117 	/** Initialized with readdirplus */
118 	FUSE_I_INIT_RDPLUS,
119 	/** An operation changing file size is in progress  */
120 	FUSE_I_SIZE_UNSTABLE,
121 };
122 
123 struct fuse_conn;
124 
125 /** FUSE specific file data */
126 struct fuse_file {
127 	/** Fuse connection for this file */
128 	struct fuse_conn *fc;
129 
130 	/** Request reserved for flush and release */
131 	struct fuse_req *reserved_req;
132 
133 	/** Kernel file handle guaranteed to be unique */
134 	u64 kh;
135 
136 	/** File handle used by userspace */
137 	u64 fh;
138 
139 	/** Node id of this file */
140 	u64 nodeid;
141 
142 	/** Refcount */
143 	refcount_t count;
144 
145 	/** FOPEN_* flags returned by open */
146 	u32 open_flags;
147 
148 	/** Entry on inode's write_files list */
149 	struct list_head write_entry;
150 
151 	/** RB node to be linked on fuse_conn->polled_files */
152 	struct rb_node polled_node;
153 
154 	/** Wait queue head for poll */
155 	wait_queue_head_t poll_wait;
156 
157 	/** Has flock been performed on this file? */
158 	bool flock:1;
159 };
160 
161 /** One input argument of a request */
162 struct fuse_in_arg {
163 	unsigned size;
164 	const void *value;
165 };
166 
167 /** The request input */
168 struct fuse_in {
169 	/** The request header */
170 	struct fuse_in_header h;
171 
172 	/** True if the data for the last argument is in req->pages */
173 	unsigned argpages:1;
174 
175 	/** Number of arguments */
176 	unsigned numargs;
177 
178 	/** Array of arguments */
179 	struct fuse_in_arg args[3];
180 };
181 
182 /** One output argument of a request */
183 struct fuse_arg {
184 	unsigned size;
185 	void *value;
186 };
187 
188 /** The request output */
189 struct fuse_out {
190 	/** Header returned from userspace */
191 	struct fuse_out_header h;
192 
193 	/*
194 	 * The following bitfields are not changed during the request
195 	 * processing
196 	 */
197 
198 	/** Last argument is variable length (can be shorter than
199 	    arg->size) */
200 	unsigned argvar:1;
201 
202 	/** Last argument is a list of pages to copy data to */
203 	unsigned argpages:1;
204 
205 	/** Zero partially or not copied pages */
206 	unsigned page_zeroing:1;
207 
208 	/** Pages may be replaced with new ones */
209 	unsigned page_replace:1;
210 
211 	/** Number or arguments */
212 	unsigned numargs;
213 
214 	/** Array of arguments */
215 	struct fuse_arg args[2];
216 };
217 
218 /** FUSE page descriptor */
219 struct fuse_page_desc {
220 	unsigned int length;
221 	unsigned int offset;
222 };
223 
224 struct fuse_args {
225 	struct {
226 		struct {
227 			uint32_t opcode;
228 			uint64_t nodeid;
229 		} h;
230 		unsigned numargs;
231 		struct fuse_in_arg args[3];
232 
233 	} in;
234 	struct {
235 		unsigned argvar:1;
236 		unsigned numargs;
237 		struct fuse_arg args[2];
238 	} out;
239 };
240 
241 #define FUSE_ARGS(args) struct fuse_args args = {}
242 
243 /** The request IO state (for asynchronous processing) */
244 struct fuse_io_priv {
245 	struct kref refcnt;
246 	int async;
247 	spinlock_t lock;
248 	unsigned reqs;
249 	ssize_t bytes;
250 	size_t size;
251 	__u64 offset;
252 	bool write;
253 	bool should_dirty;
254 	int err;
255 	struct kiocb *iocb;
256 	struct completion *done;
257 	bool blocking;
258 };
259 
260 #define FUSE_IO_PRIV_SYNC(i) \
261 {					\
262 	.refcnt = KREF_INIT(1),		\
263 	.async = 0,			\
264 	.iocb = i,			\
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 	/** The user namespace for this mount */
471 	struct user_namespace *user_ns;
472 
473 	/** Maximum read size */
474 	unsigned max_read;
475 
476 	/** Maximum write size */
477 	unsigned max_write;
478 
479 	/** Input queue */
480 	struct fuse_iqueue iq;
481 
482 	/** The next unique kernel file handle */
483 	u64 khctr;
484 
485 	/** rbtree of fuse_files waiting for poll events indexed by ph */
486 	struct rb_root polled_files;
487 
488 	/** Maximum number of outstanding background requests */
489 	unsigned max_background;
490 
491 	/** Number of background requests at which congestion starts */
492 	unsigned congestion_threshold;
493 
494 	/** Number of requests currently in the background */
495 	unsigned num_background;
496 
497 	/** Number of background requests currently queued for userspace */
498 	unsigned active_background;
499 
500 	/** The list of background requests set aside for later queuing */
501 	struct list_head bg_queue;
502 
503 	/** Flag indicating that INIT reply has been received. Allocating
504 	 * any fuse request will be suspended until the flag is set */
505 	int initialized;
506 
507 	/** Flag indicating if connection is blocked.  This will be
508 	    the case before the INIT reply is received, and if there
509 	    are too many outstading backgrounds requests */
510 	int blocked;
511 
512 	/** waitq for blocked connection */
513 	wait_queue_head_t blocked_waitq;
514 
515 	/** waitq for reserved requests */
516 	wait_queue_head_t reserved_req_waitq;
517 
518 	/** Connection established, cleared on umount, connection
519 	    abort and device release */
520 	unsigned connected;
521 
522 	/** Connection aborted via sysfs */
523 	bool aborted;
524 
525 	/** Connection failed (version mismatch).  Cannot race with
526 	    setting other bitfields since it is only set once in INIT
527 	    reply, before any other request, and never cleared */
528 	unsigned conn_error:1;
529 
530 	/** Connection successful.  Only set in INIT */
531 	unsigned conn_init:1;
532 
533 	/** Do readpages asynchronously?  Only set in INIT */
534 	unsigned async_read:1;
535 
536 	/** Return an unique read error after abort.  Only set in INIT */
537 	unsigned abort_err:1;
538 
539 	/** Do not send separate SETATTR request before open(O_TRUNC)  */
540 	unsigned atomic_o_trunc:1;
541 
542 	/** Filesystem supports NFS exporting.  Only set in INIT */
543 	unsigned export_support:1;
544 
545 	/** write-back cache policy (default is write-through) */
546 	unsigned writeback_cache:1;
547 
548 	/** allow parallel lookups and readdir (default is serialized) */
549 	unsigned parallel_dirops:1;
550 
551 	/** handle fs handles killing suid/sgid/cap on write/chown/trunc */
552 	unsigned handle_killpriv:1;
553 
554 	/*
555 	 * The following bitfields are only for optimization purposes
556 	 * and hence races in setting them will not cause malfunction
557 	 */
558 
559 	/** Is open/release not implemented by fs? */
560 	unsigned no_open:1;
561 
562 	/** Is fsync not implemented by fs? */
563 	unsigned no_fsync:1;
564 
565 	/** Is fsyncdir not implemented by fs? */
566 	unsigned no_fsyncdir:1;
567 
568 	/** Is flush not implemented by fs? */
569 	unsigned no_flush:1;
570 
571 	/** Is setxattr not implemented by fs? */
572 	unsigned no_setxattr:1;
573 
574 	/** Is getxattr not implemented by fs? */
575 	unsigned no_getxattr:1;
576 
577 	/** Is listxattr not implemented by fs? */
578 	unsigned no_listxattr:1;
579 
580 	/** Is removexattr not implemented by fs? */
581 	unsigned no_removexattr:1;
582 
583 	/** Are posix file locking primitives not implemented by fs? */
584 	unsigned no_lock:1;
585 
586 	/** Is access not implemented by fs? */
587 	unsigned no_access:1;
588 
589 	/** Is create not implemented by fs? */
590 	unsigned no_create:1;
591 
592 	/** Is interrupt not implemented by fs? */
593 	unsigned no_interrupt:1;
594 
595 	/** Is bmap not implemented by fs? */
596 	unsigned no_bmap:1;
597 
598 	/** Is poll not implemented by fs? */
599 	unsigned no_poll:1;
600 
601 	/** Do multi-page cached writes */
602 	unsigned big_writes:1;
603 
604 	/** Don't apply umask to creation modes */
605 	unsigned dont_mask:1;
606 
607 	/** Are BSD file locking primitives not implemented by fs? */
608 	unsigned no_flock:1;
609 
610 	/** Is fallocate not implemented by fs? */
611 	unsigned no_fallocate:1;
612 
613 	/** Is rename with flags implemented by fs? */
614 	unsigned no_rename2:1;
615 
616 	/** Use enhanced/automatic page cache invalidation. */
617 	unsigned auto_inval_data:1;
618 
619 	/** Does the filesystem support readdirplus? */
620 	unsigned do_readdirplus:1;
621 
622 	/** Does the filesystem want adaptive readdirplus? */
623 	unsigned readdirplus_auto:1;
624 
625 	/** Does the filesystem support asynchronous direct-IO submission? */
626 	unsigned async_dio:1;
627 
628 	/** Is lseek not implemented by fs? */
629 	unsigned no_lseek:1;
630 
631 	/** Does the filesystem support posix acls? */
632 	unsigned posix_acl:1;
633 
634 	/** Check permissions based on the file mode or not? */
635 	unsigned default_permissions:1;
636 
637 	/** Allow other than the mounter user to access the filesystem ? */
638 	unsigned allow_other:1;
639 
640 	/** The number of requests waiting for completion */
641 	atomic_t num_waiting;
642 
643 	/** Negotiated minor version */
644 	unsigned minor;
645 
646 	/** Entry on the fuse_conn_list */
647 	struct list_head entry;
648 
649 	/** Device ID from super block */
650 	dev_t dev;
651 
652 	/** Dentries in the control filesystem */
653 	struct dentry *ctl_dentry[FUSE_CTL_NUM_DENTRIES];
654 
655 	/** number of dentries used in the above array */
656 	int ctl_ndents;
657 
658 	/** Key for lock owner ID scrambling */
659 	u32 scramble_key[4];
660 
661 	/** Reserved request for the DESTROY message */
662 	struct fuse_req *destroy_req;
663 
664 	/** Version counter for attribute changes */
665 	u64 attr_version;
666 
667 	/** Called on final put */
668 	void (*release)(struct fuse_conn *);
669 
670 	/** Super block for this connection. */
671 	struct super_block *sb;
672 
673 	/** Read/write semaphore to hold when accessing sb. */
674 	struct rw_semaphore killsb;
675 
676 	/** List of device instances belonging to this connection */
677 	struct list_head devices;
678 };
679 
680 static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb)
681 {
682 	return sb->s_fs_info;
683 }
684 
685 static inline struct fuse_conn *get_fuse_conn(struct inode *inode)
686 {
687 	return get_fuse_conn_super(inode->i_sb);
688 }
689 
690 static inline struct fuse_inode *get_fuse_inode(struct inode *inode)
691 {
692 	return container_of(inode, struct fuse_inode, inode);
693 }
694 
695 static inline u64 get_node_id(struct inode *inode)
696 {
697 	return get_fuse_inode(inode)->nodeid;
698 }
699 
700 /** Device operations */
701 extern const struct file_operations fuse_dev_operations;
702 
703 extern const struct dentry_operations fuse_dentry_operations;
704 extern const struct dentry_operations fuse_root_dentry_operations;
705 
706 /**
707  * Inode to nodeid comparison.
708  */
709 int fuse_inode_eq(struct inode *inode, void *_nodeidp);
710 
711 /**
712  * Get a filled in inode
713  */
714 struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
715 			int generation, struct fuse_attr *attr,
716 			u64 attr_valid, u64 attr_version);
717 
718 int fuse_lookup_name(struct super_block *sb, u64 nodeid, const struct qstr *name,
719 		     struct fuse_entry_out *outarg, struct inode **inode);
720 
721 /**
722  * Send FORGET command
723  */
724 void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget,
725 		       u64 nodeid, u64 nlookup);
726 
727 struct fuse_forget_link *fuse_alloc_forget(void);
728 
729 /* Used by READDIRPLUS */
730 void fuse_force_forget(struct file *file, u64 nodeid);
731 
732 /**
733  * Initialize READ or READDIR request
734  */
735 void fuse_read_fill(struct fuse_req *req, struct file *file,
736 		    loff_t pos, size_t count, int opcode);
737 
738 /**
739  * Send OPEN or OPENDIR request
740  */
741 int fuse_open_common(struct inode *inode, struct file *file, bool isdir);
742 
743 struct fuse_file *fuse_file_alloc(struct fuse_conn *fc);
744 void fuse_file_free(struct fuse_file *ff);
745 void fuse_finish_open(struct inode *inode, struct file *file);
746 
747 void fuse_sync_release(struct fuse_file *ff, int flags);
748 
749 /**
750  * Send RELEASE or RELEASEDIR request
751  */
752 void fuse_release_common(struct file *file, int opcode);
753 
754 /**
755  * Send FSYNC or FSYNCDIR request
756  */
757 int fuse_fsync_common(struct file *file, loff_t start, loff_t end,
758 		      int datasync, int isdir);
759 
760 /**
761  * Notify poll wakeup
762  */
763 int fuse_notify_poll_wakeup(struct fuse_conn *fc,
764 			    struct fuse_notify_poll_wakeup_out *outarg);
765 
766 /**
767  * Initialize file operations on a regular file
768  */
769 void fuse_init_file_inode(struct inode *inode);
770 
771 /**
772  * Initialize inode operations on regular files and special files
773  */
774 void fuse_init_common(struct inode *inode);
775 
776 /**
777  * Initialize inode and file operations on a directory
778  */
779 void fuse_init_dir(struct inode *inode);
780 
781 /**
782  * Initialize inode operations on a symlink
783  */
784 void fuse_init_symlink(struct inode *inode);
785 
786 /**
787  * Change attributes of an inode
788  */
789 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
790 			    u64 attr_valid, u64 attr_version);
791 
792 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
793 				   u64 attr_valid);
794 
795 /**
796  * Initialize the client device
797  */
798 int fuse_dev_init(void);
799 
800 /**
801  * Cleanup the client device
802  */
803 void fuse_dev_cleanup(void);
804 
805 int fuse_ctl_init(void);
806 void __exit fuse_ctl_cleanup(void);
807 
808 /**
809  * Allocate a request
810  */
811 struct fuse_req *fuse_request_alloc(unsigned npages);
812 
813 struct fuse_req *fuse_request_alloc_nofs(unsigned npages);
814 
815 /**
816  * Free a request
817  */
818 void fuse_request_free(struct fuse_req *req);
819 
820 /**
821  * Get a request, may fail with -ENOMEM,
822  * caller should specify # elements in req->pages[] explicitly
823  */
824 struct fuse_req *fuse_get_req(struct fuse_conn *fc, unsigned npages);
825 struct fuse_req *fuse_get_req_for_background(struct fuse_conn *fc,
826 					     unsigned npages);
827 
828 /*
829  * Increment reference count on request
830  */
831 void __fuse_get_request(struct fuse_req *req);
832 
833 /**
834  * Gets a requests for a file operation, always succeeds
835  */
836 struct fuse_req *fuse_get_req_nofail_nopages(struct fuse_conn *fc,
837 					     struct file *file);
838 
839 /**
840  * Decrement reference count of a request.  If count goes to zero free
841  * the request.
842  */
843 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req);
844 
845 /**
846  * Send a request (synchronous)
847  */
848 void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req);
849 
850 /**
851  * Simple request sending that does request allocation and freeing
852  */
853 ssize_t fuse_simple_request(struct fuse_conn *fc, struct fuse_args *args);
854 
855 /**
856  * Send a request in the background
857  */
858 void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req);
859 
860 void fuse_request_send_background_locked(struct fuse_conn *fc,
861 					 struct fuse_req *req);
862 
863 /* Abort all requests */
864 void fuse_abort_conn(struct fuse_conn *fc, bool is_abort);
865 void fuse_wait_aborted(struct fuse_conn *fc);
866 
867 /**
868  * Invalidate inode attributes
869  */
870 void fuse_invalidate_attr(struct inode *inode);
871 
872 void fuse_invalidate_entry_cache(struct dentry *entry);
873 
874 void fuse_invalidate_atime(struct inode *inode);
875 
876 /**
877  * Acquire reference to fuse_conn
878  */
879 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc);
880 
881 /**
882  * Initialize fuse_conn
883  */
884 void fuse_conn_init(struct fuse_conn *fc, struct user_namespace *user_ns);
885 
886 /**
887  * Release reference to fuse_conn
888  */
889 void fuse_conn_put(struct fuse_conn *fc);
890 
891 struct fuse_dev *fuse_dev_alloc(struct fuse_conn *fc);
892 void fuse_dev_free(struct fuse_dev *fud);
893 
894 /**
895  * Add connection to control filesystem
896  */
897 int fuse_ctl_add_conn(struct fuse_conn *fc);
898 
899 /**
900  * Remove connection from control filesystem
901  */
902 void fuse_ctl_remove_conn(struct fuse_conn *fc);
903 
904 /**
905  * Is file type valid?
906  */
907 int fuse_valid_type(int m);
908 
909 /**
910  * Is current process allowed to perform filesystem operation?
911  */
912 int fuse_allow_current_process(struct fuse_conn *fc);
913 
914 u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id);
915 
916 void fuse_update_ctime(struct inode *inode);
917 
918 int fuse_update_attributes(struct inode *inode, struct file *file);
919 
920 void fuse_flush_writepages(struct inode *inode);
921 
922 void fuse_set_nowrite(struct inode *inode);
923 void fuse_release_nowrite(struct inode *inode);
924 
925 u64 fuse_get_attr_version(struct fuse_conn *fc);
926 
927 /**
928  * File-system tells the kernel to invalidate cache for the given node id.
929  */
930 int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid,
931 			     loff_t offset, loff_t len);
932 
933 /**
934  * File-system tells the kernel to invalidate parent attributes and
935  * the dentry matching parent/name.
936  *
937  * If the child_nodeid is non-zero and:
938  *    - matches the inode number for the dentry matching parent/name,
939  *    - is not a mount point
940  *    - is a file or oan empty directory
941  * then the dentry is unhashed (d_delete()).
942  */
943 int fuse_reverse_inval_entry(struct super_block *sb, u64 parent_nodeid,
944 			     u64 child_nodeid, struct qstr *name);
945 
946 int fuse_do_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
947 		 bool isdir);
948 
949 /**
950  * fuse_direct_io() flags
951  */
952 
953 /** If set, it is WRITE; otherwise - READ */
954 #define FUSE_DIO_WRITE (1 << 0)
955 
956 /** CUSE pass fuse_direct_io() a file which f_mapping->host is not from FUSE */
957 #define FUSE_DIO_CUSE  (1 << 1)
958 
959 ssize_t fuse_direct_io(struct fuse_io_priv *io, struct iov_iter *iter,
960 		       loff_t *ppos, int flags);
961 long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
962 		   unsigned int flags);
963 long fuse_ioctl_common(struct file *file, unsigned int cmd,
964 		       unsigned long arg, unsigned int flags);
965 __poll_t fuse_file_poll(struct file *file, poll_table *wait);
966 int fuse_dev_release(struct inode *inode, struct file *file);
967 
968 bool fuse_write_update_size(struct inode *inode, loff_t pos);
969 
970 int fuse_flush_times(struct inode *inode, struct fuse_file *ff);
971 int fuse_write_inode(struct inode *inode, struct writeback_control *wbc);
972 
973 int fuse_do_setattr(struct dentry *dentry, struct iattr *attr,
974 		    struct file *file);
975 
976 void fuse_set_initialized(struct fuse_conn *fc);
977 
978 void fuse_unlock_inode(struct inode *inode, bool locked);
979 bool fuse_lock_inode(struct inode *inode);
980 
981 int fuse_setxattr(struct inode *inode, const char *name, const void *value,
982 		  size_t size, int flags);
983 ssize_t fuse_getxattr(struct inode *inode, const char *name, void *value,
984 		      size_t size);
985 ssize_t fuse_listxattr(struct dentry *entry, char *list, size_t size);
986 int fuse_removexattr(struct inode *inode, const char *name);
987 extern const struct xattr_handler *fuse_xattr_handlers[];
988 extern const struct xattr_handler *fuse_acl_xattr_handlers[];
989 extern const struct xattr_handler *fuse_no_acl_xattr_handlers[];
990 
991 struct posix_acl;
992 struct posix_acl *fuse_get_acl(struct inode *inode, int type);
993 int fuse_set_acl(struct inode *inode, struct posix_acl *acl, int type);
994 
995 #endif /* _FS_FUSE_I_H */
996