xref: /openbmc/linux/fs/fuse/fuse_i.h (revision 04ec5af0776e9baefed59891f12adbcb5fa71a23)
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 #ifndef pr_fmt
13 # define pr_fmt(fmt) "fuse: " fmt
14 #endif
15 
16 #include <linux/fuse.h>
17 #include <linux/fs.h>
18 #include <linux/mount.h>
19 #include <linux/wait.h>
20 #include <linux/list.h>
21 #include <linux/spinlock.h>
22 #include <linux/mm.h>
23 #include <linux/backing-dev.h>
24 #include <linux/mutex.h>
25 #include <linux/rwsem.h>
26 #include <linux/rbtree.h>
27 #include <linux/poll.h>
28 #include <linux/workqueue.h>
29 #include <linux/kref.h>
30 #include <linux/xattr.h>
31 #include <linux/pid_namespace.h>
32 #include <linux/refcount.h>
33 #include <linux/user_namespace.h>
34 
35 /** Default max number of pages that can be used in a single read request */
36 #define FUSE_DEFAULT_MAX_PAGES_PER_REQ 32
37 
38 /** Maximum of max_pages received in init_out */
39 #define FUSE_MAX_MAX_PAGES 256
40 
41 /** Bias for fi->writectr, meaning new writepages must not be sent */
42 #define FUSE_NOWRITE INT_MIN
43 
44 /** It could be as large as PATH_MAX, but would that have any uses? */
45 #define FUSE_NAME_MAX 1024
46 
47 /** Number of dentries for each connection in the control filesystem */
48 #define FUSE_CTL_NUM_DENTRIES 5
49 
50 /** List of active connections */
51 extern struct list_head fuse_conn_list;
52 
53 /** Global mutex protecting fuse_conn_list and the control filesystem */
54 extern struct mutex fuse_mutex;
55 
56 /** Module parameters */
57 extern unsigned max_user_bgreq;
58 extern unsigned max_user_congthresh;
59 
60 /* One forget request */
61 struct fuse_forget_link {
62 	struct fuse_forget_one forget_one;
63 	struct fuse_forget_link *next;
64 };
65 
66 /** FUSE inode */
67 struct fuse_inode {
68 	/** Inode data */
69 	struct inode inode;
70 
71 	/** Unique ID, which identifies the inode between userspace
72 	 * and kernel */
73 	u64 nodeid;
74 
75 	/** Number of lookups on this inode */
76 	u64 nlookup;
77 
78 	/** The request used for sending the FORGET message */
79 	struct fuse_forget_link *forget;
80 
81 	/** Time in jiffies until the file attributes are valid */
82 	u64 i_time;
83 
84 	/* Which attributes are invalid */
85 	u32 inval_mask;
86 
87 	/** The sticky bit in inode->i_mode may have been removed, so
88 	    preserve the original mode */
89 	umode_t orig_i_mode;
90 
91 	/** 64 bit inode number */
92 	u64 orig_ino;
93 
94 	/** Version of last attribute change */
95 	u64 attr_version;
96 
97 	union {
98 		/* Write related fields (regular file only) */
99 		struct {
100 			/* Files usable in writepage.  Protected by fi->lock */
101 			struct list_head write_files;
102 
103 			/* Writepages pending on truncate or fsync */
104 			struct list_head queued_writes;
105 
106 			/* Number of sent writes, a negative bias
107 			 * (FUSE_NOWRITE) means more writes are blocked */
108 			int writectr;
109 
110 			/* Waitq for writepage completion */
111 			wait_queue_head_t page_waitq;
112 
113 			/* List of writepage requestst (pending or sent) */
114 			struct list_head writepages;
115 		};
116 
117 		/* readdir cache (directory only) */
118 		struct {
119 			/* true if fully cached */
120 			bool cached;
121 
122 			/* size of cache */
123 			loff_t size;
124 
125 			/* position at end of cache (position of next entry) */
126 			loff_t pos;
127 
128 			/* version of the cache */
129 			u64 version;
130 
131 			/* modification time of directory when cache was
132 			 * started */
133 			struct timespec64 mtime;
134 
135 			/* iversion of directory when cache was started */
136 			u64 iversion;
137 
138 			/* protects above fields */
139 			spinlock_t lock;
140 		} rdc;
141 	};
142 
143 	/** Miscellaneous bits describing inode state */
144 	unsigned long state;
145 
146 	/** Lock for serializing lookup and readdir for back compatibility*/
147 	struct mutex mutex;
148 
149 	/** Lock to protect write related fields */
150 	spinlock_t lock;
151 };
152 
153 /** FUSE inode state bits */
154 enum {
155 	/** Advise readdirplus  */
156 	FUSE_I_ADVISE_RDPLUS,
157 	/** Initialized with readdirplus */
158 	FUSE_I_INIT_RDPLUS,
159 	/** An operation changing file size is in progress  */
160 	FUSE_I_SIZE_UNSTABLE,
161 };
162 
163 struct fuse_conn;
164 struct fuse_release_args;
165 
166 /** FUSE specific file data */
167 struct fuse_file {
168 	/** Fuse connection for this file */
169 	struct fuse_conn *fc;
170 
171 	/* Argument space reserved for release */
172 	struct fuse_release_args *release_args;
173 
174 	/** Kernel file handle guaranteed to be unique */
175 	u64 kh;
176 
177 	/** File handle used by userspace */
178 	u64 fh;
179 
180 	/** Node id of this file */
181 	u64 nodeid;
182 
183 	/** Refcount */
184 	refcount_t count;
185 
186 	/** FOPEN_* flags returned by open */
187 	u32 open_flags;
188 
189 	/** Entry on inode's write_files list */
190 	struct list_head write_entry;
191 
192 	/* Readdir related */
193 	struct {
194 		/*
195 		 * Protects below fields against (crazy) parallel readdir on
196 		 * same open file.  Uncontended in the normal case.
197 		 */
198 		struct mutex lock;
199 
200 		/* Dir stream position */
201 		loff_t pos;
202 
203 		/* Offset in cache */
204 		loff_t cache_off;
205 
206 		/* Version of cache we are reading */
207 		u64 version;
208 
209 	} readdir;
210 
211 	/** RB node to be linked on fuse_conn->polled_files */
212 	struct rb_node polled_node;
213 
214 	/** Wait queue head for poll */
215 	wait_queue_head_t poll_wait;
216 
217 	/** Has flock been performed on this file? */
218 	bool flock:1;
219 };
220 
221 /** One input argument of a request */
222 struct fuse_in_arg {
223 	unsigned size;
224 	const void *value;
225 };
226 
227 /** One output argument of a request */
228 struct fuse_arg {
229 	unsigned size;
230 	void *value;
231 };
232 
233 /** FUSE page descriptor */
234 struct fuse_page_desc {
235 	unsigned int length;
236 	unsigned int offset;
237 };
238 
239 struct fuse_args {
240 	uint64_t nodeid;
241 	uint32_t opcode;
242 	unsigned short in_numargs;
243 	unsigned short out_numargs;
244 	bool force:1;
245 	bool noreply:1;
246 	bool nocreds:1;
247 	bool in_pages:1;
248 	bool out_pages:1;
249 	bool out_argvar:1;
250 	bool page_zeroing:1;
251 	bool page_replace:1;
252 	struct fuse_in_arg in_args[3];
253 	struct fuse_arg out_args[2];
254 	void (*end)(struct fuse_conn *fc, struct fuse_args *args, int error);
255 };
256 
257 struct fuse_args_pages {
258 	struct fuse_args args;
259 	struct page **pages;
260 	struct fuse_page_desc *descs;
261 	unsigned int num_pages;
262 };
263 
264 #define FUSE_ARGS(args) struct fuse_args args = {}
265 
266 /** The request IO state (for asynchronous processing) */
267 struct fuse_io_priv {
268 	struct kref refcnt;
269 	int async;
270 	spinlock_t lock;
271 	unsigned reqs;
272 	ssize_t bytes;
273 	size_t size;
274 	__u64 offset;
275 	bool write;
276 	bool should_dirty;
277 	int err;
278 	struct kiocb *iocb;
279 	struct completion *done;
280 	bool blocking;
281 };
282 
283 #define FUSE_IO_PRIV_SYNC(i) \
284 {					\
285 	.refcnt = KREF_INIT(1),		\
286 	.async = 0,			\
287 	.iocb = i,			\
288 }
289 
290 /**
291  * Request flags
292  *
293  * FR_ISREPLY:		set if the request has reply
294  * FR_FORCE:		force sending of the request even if interrupted
295  * FR_BACKGROUND:	request is sent in the background
296  * FR_WAITING:		request is counted as "waiting"
297  * FR_ABORTED:		the request was aborted
298  * FR_INTERRUPTED:	the request has been interrupted
299  * FR_LOCKED:		data is being copied to/from the request
300  * FR_PENDING:		request is not yet in userspace
301  * FR_SENT:		request is in userspace, waiting for an answer
302  * FR_FINISHED:		request is finished
303  * FR_PRIVATE:		request is on private list
304  */
305 enum fuse_req_flag {
306 	FR_ISREPLY,
307 	FR_FORCE,
308 	FR_BACKGROUND,
309 	FR_WAITING,
310 	FR_ABORTED,
311 	FR_INTERRUPTED,
312 	FR_LOCKED,
313 	FR_PENDING,
314 	FR_SENT,
315 	FR_FINISHED,
316 	FR_PRIVATE,
317 };
318 
319 /**
320  * A request to the client
321  *
322  * .waitq.lock protects the following fields:
323  *   - FR_ABORTED
324  *   - FR_LOCKED (may also be modified under fc->lock, tested under both)
325  */
326 struct fuse_req {
327 	/** This can be on either pending processing or io lists in
328 	    fuse_conn */
329 	struct list_head list;
330 
331 	/** Entry on the interrupts list  */
332 	struct list_head intr_entry;
333 
334 	/* Input/output arguments */
335 	struct fuse_args *args;
336 
337 	/** refcount */
338 	refcount_t count;
339 
340 	/* Request flags, updated with test/set/clear_bit() */
341 	unsigned long flags;
342 
343 	/* The request input header */
344 	struct {
345 		struct fuse_in_header h;
346 	} in;
347 
348 	/* The request output header */
349 	struct {
350 		struct fuse_out_header h;
351 	} out;
352 
353 	/** Used to wake up the task waiting for completion of request*/
354 	wait_queue_head_t waitq;
355 
356 };
357 
358 struct fuse_iqueue {
359 	/** Connection established */
360 	unsigned connected;
361 
362 	/** Lock protecting accesses to members of this structure */
363 	spinlock_t lock;
364 
365 	/** Readers of the connection are waiting on this */
366 	wait_queue_head_t waitq;
367 
368 	/** The next unique request id */
369 	u64 reqctr;
370 
371 	/** The list of pending requests */
372 	struct list_head pending;
373 
374 	/** Pending interrupts */
375 	struct list_head interrupts;
376 
377 	/** Queue of pending forgets */
378 	struct fuse_forget_link forget_list_head;
379 	struct fuse_forget_link *forget_list_tail;
380 
381 	/** Batching of FORGET requests (positive indicates FORGET batch) */
382 	int forget_batch;
383 
384 	/** O_ASYNC requests */
385 	struct fasync_struct *fasync;
386 };
387 
388 #define FUSE_PQ_HASH_BITS 8
389 #define FUSE_PQ_HASH_SIZE (1 << FUSE_PQ_HASH_BITS)
390 
391 struct fuse_pqueue {
392 	/** Connection established */
393 	unsigned connected;
394 
395 	/** Lock protecting accessess to  members of this structure */
396 	spinlock_t lock;
397 
398 	/** Hash table of requests being processed */
399 	struct list_head *processing;
400 
401 	/** The list of requests under I/O */
402 	struct list_head io;
403 };
404 
405 /**
406  * Fuse device instance
407  */
408 struct fuse_dev {
409 	/** Fuse connection for this device */
410 	struct fuse_conn *fc;
411 
412 	/** Processing queue */
413 	struct fuse_pqueue pq;
414 
415 	/** list entry on fc->devices */
416 	struct list_head entry;
417 };
418 
419 /**
420  * A Fuse connection.
421  *
422  * This structure is created, when the filesystem is mounted, and is
423  * destroyed, when the client device is closed and the filesystem is
424  * unmounted.
425  */
426 struct fuse_conn {
427 	/** Lock protecting accessess to  members of this structure */
428 	spinlock_t lock;
429 
430 	/** Refcount */
431 	refcount_t count;
432 
433 	/** Number of fuse_dev's */
434 	atomic_t dev_count;
435 
436 	struct rcu_head rcu;
437 
438 	/** The user id for this mount */
439 	kuid_t user_id;
440 
441 	/** The group id for this mount */
442 	kgid_t group_id;
443 
444 	/** The pid namespace for this mount */
445 	struct pid_namespace *pid_ns;
446 
447 	/** The user namespace for this mount */
448 	struct user_namespace *user_ns;
449 
450 	/** Maximum read size */
451 	unsigned max_read;
452 
453 	/** Maximum write size */
454 	unsigned max_write;
455 
456 	/** Maxmum number of pages that can be used in a single request */
457 	unsigned int max_pages;
458 
459 	/** Input queue */
460 	struct fuse_iqueue iq;
461 
462 	/** The next unique kernel file handle */
463 	atomic64_t khctr;
464 
465 	/** rbtree of fuse_files waiting for poll events indexed by ph */
466 	struct rb_root polled_files;
467 
468 	/** Maximum number of outstanding background requests */
469 	unsigned max_background;
470 
471 	/** Number of background requests at which congestion starts */
472 	unsigned congestion_threshold;
473 
474 	/** Number of requests currently in the background */
475 	unsigned num_background;
476 
477 	/** Number of background requests currently queued for userspace */
478 	unsigned active_background;
479 
480 	/** The list of background requests set aside for later queuing */
481 	struct list_head bg_queue;
482 
483 	/** Protects: max_background, congestion_threshold, num_background,
484 	 * active_background, bg_queue, blocked */
485 	spinlock_t bg_lock;
486 
487 	/** Flag indicating that INIT reply has been received. Allocating
488 	 * any fuse request will be suspended until the flag is set */
489 	int initialized;
490 
491 	/** Flag indicating if connection is blocked.  This will be
492 	    the case before the INIT reply is received, and if there
493 	    are too many outstading backgrounds requests */
494 	int blocked;
495 
496 	/** waitq for blocked connection */
497 	wait_queue_head_t blocked_waitq;
498 
499 	/** Connection established, cleared on umount, connection
500 	    abort and device release */
501 	unsigned connected;
502 
503 	/** Connection aborted via sysfs */
504 	bool aborted;
505 
506 	/** Connection failed (version mismatch).  Cannot race with
507 	    setting other bitfields since it is only set once in INIT
508 	    reply, before any other request, and never cleared */
509 	unsigned conn_error:1;
510 
511 	/** Connection successful.  Only set in INIT */
512 	unsigned conn_init:1;
513 
514 	/** Do readpages asynchronously?  Only set in INIT */
515 	unsigned async_read:1;
516 
517 	/** Return an unique read error after abort.  Only set in INIT */
518 	unsigned abort_err:1;
519 
520 	/** Do not send separate SETATTR request before open(O_TRUNC)  */
521 	unsigned atomic_o_trunc:1;
522 
523 	/** Filesystem supports NFS exporting.  Only set in INIT */
524 	unsigned export_support:1;
525 
526 	/** write-back cache policy (default is write-through) */
527 	unsigned writeback_cache:1;
528 
529 	/** allow parallel lookups and readdir (default is serialized) */
530 	unsigned parallel_dirops:1;
531 
532 	/** handle fs handles killing suid/sgid/cap on write/chown/trunc */
533 	unsigned handle_killpriv:1;
534 
535 	/** cache READLINK responses in page cache */
536 	unsigned cache_symlinks:1;
537 
538 	/*
539 	 * The following bitfields are only for optimization purposes
540 	 * and hence races in setting them will not cause malfunction
541 	 */
542 
543 	/** Is open/release not implemented by fs? */
544 	unsigned no_open:1;
545 
546 	/** Is opendir/releasedir not implemented by fs? */
547 	unsigned no_opendir:1;
548 
549 	/** Is fsync not implemented by fs? */
550 	unsigned no_fsync:1;
551 
552 	/** Is fsyncdir not implemented by fs? */
553 	unsigned no_fsyncdir:1;
554 
555 	/** Is flush not implemented by fs? */
556 	unsigned no_flush:1;
557 
558 	/** Is setxattr not implemented by fs? */
559 	unsigned no_setxattr:1;
560 
561 	/** Is getxattr not implemented by fs? */
562 	unsigned no_getxattr:1;
563 
564 	/** Is listxattr not implemented by fs? */
565 	unsigned no_listxattr:1;
566 
567 	/** Is removexattr not implemented by fs? */
568 	unsigned no_removexattr:1;
569 
570 	/** Are posix file locking primitives not implemented by fs? */
571 	unsigned no_lock:1;
572 
573 	/** Is access not implemented by fs? */
574 	unsigned no_access:1;
575 
576 	/** Is create not implemented by fs? */
577 	unsigned no_create:1;
578 
579 	/** Is interrupt not implemented by fs? */
580 	unsigned no_interrupt:1;
581 
582 	/** Is bmap not implemented by fs? */
583 	unsigned no_bmap:1;
584 
585 	/** Is poll not implemented by fs? */
586 	unsigned no_poll:1;
587 
588 	/** Do multi-page cached writes */
589 	unsigned big_writes:1;
590 
591 	/** Don't apply umask to creation modes */
592 	unsigned dont_mask:1;
593 
594 	/** Are BSD file locking primitives not implemented by fs? */
595 	unsigned no_flock:1;
596 
597 	/** Is fallocate not implemented by fs? */
598 	unsigned no_fallocate:1;
599 
600 	/** Is rename with flags implemented by fs? */
601 	unsigned no_rename2:1;
602 
603 	/** Use enhanced/automatic page cache invalidation. */
604 	unsigned auto_inval_data:1;
605 
606 	/** Filesystem is fully reponsible for page cache invalidation. */
607 	unsigned explicit_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 	/** Does the filesystem support copy_file_range? */
631 	unsigned no_copy_file_range:1;
632 
633 	/* Send DESTROY request */
634 	unsigned int destroy:1;
635 
636 	/** The number of requests waiting for completion */
637 	atomic_t num_waiting;
638 
639 	/** Negotiated minor version */
640 	unsigned minor;
641 
642 	/** Entry on the fuse_conn_list */
643 	struct list_head entry;
644 
645 	/** Device ID from super block */
646 	dev_t dev;
647 
648 	/** Dentries in the control filesystem */
649 	struct dentry *ctl_dentry[FUSE_CTL_NUM_DENTRIES];
650 
651 	/** number of dentries used in the above array */
652 	int ctl_ndents;
653 
654 	/** Key for lock owner ID scrambling */
655 	u32 scramble_key[4];
656 
657 	/** Version counter for attribute changes */
658 	atomic64_t attr_version;
659 
660 	/** Called on final put */
661 	void (*release)(struct fuse_conn *);
662 
663 	/** Super block for this connection. */
664 	struct super_block *sb;
665 
666 	/** Read/write semaphore to hold when accessing sb. */
667 	struct rw_semaphore killsb;
668 
669 	/** List of device instances belonging to this connection */
670 	struct list_head devices;
671 };
672 
673 static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb)
674 {
675 	return sb->s_fs_info;
676 }
677 
678 static inline struct fuse_conn *get_fuse_conn(struct inode *inode)
679 {
680 	return get_fuse_conn_super(inode->i_sb);
681 }
682 
683 static inline struct fuse_inode *get_fuse_inode(struct inode *inode)
684 {
685 	return container_of(inode, struct fuse_inode, inode);
686 }
687 
688 static inline u64 get_node_id(struct inode *inode)
689 {
690 	return get_fuse_inode(inode)->nodeid;
691 }
692 
693 static inline int invalid_nodeid(u64 nodeid)
694 {
695 	return !nodeid || nodeid == FUSE_ROOT_ID;
696 }
697 
698 static inline u64 fuse_get_attr_version(struct fuse_conn *fc)
699 {
700 	return atomic64_read(&fc->attr_version);
701 }
702 
703 /** Device operations */
704 extern const struct file_operations fuse_dev_operations;
705 
706 extern const struct dentry_operations fuse_dentry_operations;
707 extern const struct dentry_operations fuse_root_dentry_operations;
708 
709 /**
710  * Inode to nodeid comparison.
711  */
712 int fuse_inode_eq(struct inode *inode, void *_nodeidp);
713 
714 /**
715  * Get a filled in inode
716  */
717 struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
718 			int generation, struct fuse_attr *attr,
719 			u64 attr_valid, u64 attr_version);
720 
721 int fuse_lookup_name(struct super_block *sb, u64 nodeid, const struct qstr *name,
722 		     struct fuse_entry_out *outarg, struct inode **inode);
723 
724 /**
725  * Send FORGET command
726  */
727 void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget,
728 		       u64 nodeid, u64 nlookup);
729 
730 struct fuse_forget_link *fuse_alloc_forget(void);
731 
732 /*
733  * Initialize READ or READDIR request
734  */
735 struct fuse_io_args {
736 	union {
737 		struct {
738 			struct fuse_read_in in;
739 			u64 attr_ver;
740 		} read;
741 		struct {
742 			struct fuse_write_in in;
743 			struct fuse_write_out out;
744 		} write;
745 	};
746 	struct fuse_args_pages ap;
747 	struct fuse_io_priv *io;
748 	struct fuse_file *ff;
749 };
750 
751 void fuse_read_args_fill(struct fuse_io_args *ia, struct file *file, loff_t pos,
752 			 size_t count, int opcode);
753 
754 
755 /**
756  * Send OPEN or OPENDIR request
757  */
758 int fuse_open_common(struct inode *inode, struct file *file, bool isdir);
759 
760 struct fuse_file *fuse_file_alloc(struct fuse_conn *fc);
761 void fuse_file_free(struct fuse_file *ff);
762 void fuse_finish_open(struct inode *inode, struct file *file);
763 
764 void fuse_sync_release(struct fuse_inode *fi, struct fuse_file *ff, int flags);
765 
766 /**
767  * Send RELEASE or RELEASEDIR request
768  */
769 void fuse_release_common(struct file *file, bool isdir);
770 
771 /**
772  * Send FSYNC or FSYNCDIR request
773  */
774 int fuse_fsync_common(struct file *file, loff_t start, loff_t end,
775 		      int datasync, int opcode);
776 
777 /**
778  * Notify poll wakeup
779  */
780 int fuse_notify_poll_wakeup(struct fuse_conn *fc,
781 			    struct fuse_notify_poll_wakeup_out *outarg);
782 
783 /**
784  * Initialize file operations on a regular file
785  */
786 void fuse_init_file_inode(struct inode *inode);
787 
788 /**
789  * Initialize inode operations on regular files and special files
790  */
791 void fuse_init_common(struct inode *inode);
792 
793 /**
794  * Initialize inode and file operations on a directory
795  */
796 void fuse_init_dir(struct inode *inode);
797 
798 /**
799  * Initialize inode operations on a symlink
800  */
801 void fuse_init_symlink(struct inode *inode);
802 
803 /**
804  * Change attributes of an inode
805  */
806 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
807 			    u64 attr_valid, u64 attr_version);
808 
809 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
810 				   u64 attr_valid);
811 
812 /**
813  * Initialize the client device
814  */
815 int fuse_dev_init(void);
816 
817 /**
818  * Cleanup the client device
819  */
820 void fuse_dev_cleanup(void);
821 
822 int fuse_ctl_init(void);
823 void __exit fuse_ctl_cleanup(void);
824 
825 /**
826  * Simple request sending that does request allocation and freeing
827  */
828 ssize_t fuse_simple_request(struct fuse_conn *fc, struct fuse_args *args);
829 int fuse_simple_background(struct fuse_conn *fc, struct fuse_args *args,
830 			   gfp_t gfp_flags);
831 
832 /**
833  * End a finished request
834  */
835 void fuse_request_end(struct fuse_conn *fc, struct fuse_req *req);
836 
837 /* Abort all requests */
838 void fuse_abort_conn(struct fuse_conn *fc);
839 void fuse_wait_aborted(struct fuse_conn *fc);
840 
841 /**
842  * Invalidate inode attributes
843  */
844 void fuse_invalidate_attr(struct inode *inode);
845 
846 void fuse_invalidate_entry_cache(struct dentry *entry);
847 
848 void fuse_invalidate_atime(struct inode *inode);
849 
850 u64 entry_attr_timeout(struct fuse_entry_out *o);
851 void fuse_change_entry_timeout(struct dentry *entry, struct fuse_entry_out *o);
852 
853 /**
854  * Acquire reference to fuse_conn
855  */
856 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc);
857 
858 /**
859  * Initialize fuse_conn
860  */
861 void fuse_conn_init(struct fuse_conn *fc, struct user_namespace *user_ns);
862 
863 /**
864  * Release reference to fuse_conn
865  */
866 void fuse_conn_put(struct fuse_conn *fc);
867 
868 struct fuse_dev *fuse_dev_alloc(struct fuse_conn *fc);
869 void fuse_dev_free(struct fuse_dev *fud);
870 
871 /**
872  * Add connection to control filesystem
873  */
874 int fuse_ctl_add_conn(struct fuse_conn *fc);
875 
876 /**
877  * Remove connection from control filesystem
878  */
879 void fuse_ctl_remove_conn(struct fuse_conn *fc);
880 
881 /**
882  * Is file type valid?
883  */
884 int fuse_valid_type(int m);
885 
886 /**
887  * Is current process allowed to perform filesystem operation?
888  */
889 int fuse_allow_current_process(struct fuse_conn *fc);
890 
891 u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id);
892 
893 void fuse_update_ctime(struct inode *inode);
894 
895 int fuse_update_attributes(struct inode *inode, struct file *file);
896 
897 void fuse_flush_writepages(struct inode *inode);
898 
899 void fuse_set_nowrite(struct inode *inode);
900 void fuse_release_nowrite(struct inode *inode);
901 
902 /**
903  * File-system tells the kernel to invalidate cache for the given node id.
904  */
905 int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid,
906 			     loff_t offset, loff_t len);
907 
908 /**
909  * File-system tells the kernel to invalidate parent attributes and
910  * the dentry matching parent/name.
911  *
912  * If the child_nodeid is non-zero and:
913  *    - matches the inode number for the dentry matching parent/name,
914  *    - is not a mount point
915  *    - is a file or oan empty directory
916  * then the dentry is unhashed (d_delete()).
917  */
918 int fuse_reverse_inval_entry(struct super_block *sb, u64 parent_nodeid,
919 			     u64 child_nodeid, struct qstr *name);
920 
921 int fuse_do_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
922 		 bool isdir);
923 
924 /**
925  * fuse_direct_io() flags
926  */
927 
928 /** If set, it is WRITE; otherwise - READ */
929 #define FUSE_DIO_WRITE (1 << 0)
930 
931 /** CUSE pass fuse_direct_io() a file which f_mapping->host is not from FUSE */
932 #define FUSE_DIO_CUSE  (1 << 1)
933 
934 ssize_t fuse_direct_io(struct fuse_io_priv *io, struct iov_iter *iter,
935 		       loff_t *ppos, int flags);
936 long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
937 		   unsigned int flags);
938 long fuse_ioctl_common(struct file *file, unsigned int cmd,
939 		       unsigned long arg, unsigned int flags);
940 __poll_t fuse_file_poll(struct file *file, poll_table *wait);
941 int fuse_dev_release(struct inode *inode, struct file *file);
942 
943 bool fuse_write_update_size(struct inode *inode, loff_t pos);
944 
945 int fuse_flush_times(struct inode *inode, struct fuse_file *ff);
946 int fuse_write_inode(struct inode *inode, struct writeback_control *wbc);
947 
948 int fuse_do_setattr(struct dentry *dentry, struct iattr *attr,
949 		    struct file *file);
950 
951 void fuse_set_initialized(struct fuse_conn *fc);
952 
953 void fuse_unlock_inode(struct inode *inode, bool locked);
954 bool fuse_lock_inode(struct inode *inode);
955 
956 int fuse_setxattr(struct inode *inode, const char *name, const void *value,
957 		  size_t size, int flags);
958 ssize_t fuse_getxattr(struct inode *inode, const char *name, void *value,
959 		      size_t size);
960 ssize_t fuse_listxattr(struct dentry *entry, char *list, size_t size);
961 int fuse_removexattr(struct inode *inode, const char *name);
962 extern const struct xattr_handler *fuse_xattr_handlers[];
963 extern const struct xattr_handler *fuse_acl_xattr_handlers[];
964 extern const struct xattr_handler *fuse_no_acl_xattr_handlers[];
965 
966 struct posix_acl;
967 struct posix_acl *fuse_get_acl(struct inode *inode, int type);
968 int fuse_set_acl(struct inode *inode, struct posix_acl *acl, int type);
969 
970 
971 /* readdir.c */
972 int fuse_readdir(struct file *file, struct dir_context *ctx);
973 
974 #endif /* _FS_FUSE_I_H */
975