xref: /linux/fs/fuse/fuse_i.h (revision c5d3cdad688ed75fb311a3a671eb30ba7106d7d3)
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  * FR_ASYNC:		request is asynchronous
305  */
306 enum fuse_req_flag {
307 	FR_ISREPLY,
308 	FR_FORCE,
309 	FR_BACKGROUND,
310 	FR_WAITING,
311 	FR_ABORTED,
312 	FR_INTERRUPTED,
313 	FR_LOCKED,
314 	FR_PENDING,
315 	FR_SENT,
316 	FR_FINISHED,
317 	FR_PRIVATE,
318 	FR_ASYNC,
319 };
320 
321 /**
322  * A request to the client
323  *
324  * .waitq.lock protects the following fields:
325  *   - FR_ABORTED
326  *   - FR_LOCKED (may also be modified under fc->lock, tested under both)
327  */
328 struct fuse_req {
329 	/** This can be on either pending processing or io lists in
330 	    fuse_conn */
331 	struct list_head list;
332 
333 	/** Entry on the interrupts list  */
334 	struct list_head intr_entry;
335 
336 	/* Input/output arguments */
337 	struct fuse_args *args;
338 
339 	/** refcount */
340 	refcount_t count;
341 
342 	/* Request flags, updated with test/set/clear_bit() */
343 	unsigned long flags;
344 
345 	/* The request input header */
346 	struct {
347 		struct fuse_in_header h;
348 	} in;
349 
350 	/* The request output header */
351 	struct {
352 		struct fuse_out_header h;
353 	} out;
354 
355 	/** Used to wake up the task waiting for completion of request*/
356 	wait_queue_head_t waitq;
357 
358 #if IS_ENABLED(CONFIG_VIRTIO_FS)
359 	/** virtio-fs's physically contiguous buffer for in and out args */
360 	void *argbuf;
361 #endif
362 };
363 
364 struct fuse_iqueue;
365 
366 /**
367  * Input queue callbacks
368  *
369  * Input queue signalling is device-specific.  For example, the /dev/fuse file
370  * uses fiq->waitq and fasync to wake processes that are waiting on queue
371  * readiness.  These callbacks allow other device types to respond to input
372  * queue activity.
373  */
374 struct fuse_iqueue_ops {
375 	/**
376 	 * Signal that a forget has been queued
377 	 */
378 	void (*wake_forget_and_unlock)(struct fuse_iqueue *fiq)
379 		__releases(fiq->lock);
380 
381 	/**
382 	 * Signal that an INTERRUPT request has been queued
383 	 */
384 	void (*wake_interrupt_and_unlock)(struct fuse_iqueue *fiq)
385 		__releases(fiq->lock);
386 
387 	/**
388 	 * Signal that a request has been queued
389 	 */
390 	void (*wake_pending_and_unlock)(struct fuse_iqueue *fiq)
391 		__releases(fiq->lock);
392 
393 	/**
394 	 * Clean up when fuse_iqueue is destroyed
395 	 */
396 	void (*release)(struct fuse_iqueue *fiq);
397 };
398 
399 /** /dev/fuse input queue operations */
400 extern const struct fuse_iqueue_ops fuse_dev_fiq_ops;
401 
402 struct fuse_iqueue {
403 	/** Connection established */
404 	unsigned connected;
405 
406 	/** Lock protecting accesses to members of this structure */
407 	spinlock_t lock;
408 
409 	/** Readers of the connection are waiting on this */
410 	wait_queue_head_t waitq;
411 
412 	/** The next unique request id */
413 	u64 reqctr;
414 
415 	/** The list of pending requests */
416 	struct list_head pending;
417 
418 	/** Pending interrupts */
419 	struct list_head interrupts;
420 
421 	/** Queue of pending forgets */
422 	struct fuse_forget_link forget_list_head;
423 	struct fuse_forget_link *forget_list_tail;
424 
425 	/** Batching of FORGET requests (positive indicates FORGET batch) */
426 	int forget_batch;
427 
428 	/** O_ASYNC requests */
429 	struct fasync_struct *fasync;
430 
431 	/** Device-specific callbacks */
432 	const struct fuse_iqueue_ops *ops;
433 
434 	/** Device-specific state */
435 	void *priv;
436 };
437 
438 #define FUSE_PQ_HASH_BITS 8
439 #define FUSE_PQ_HASH_SIZE (1 << FUSE_PQ_HASH_BITS)
440 
441 struct fuse_pqueue {
442 	/** Connection established */
443 	unsigned connected;
444 
445 	/** Lock protecting accessess to  members of this structure */
446 	spinlock_t lock;
447 
448 	/** Hash table of requests being processed */
449 	struct list_head *processing;
450 
451 	/** The list of requests under I/O */
452 	struct list_head io;
453 };
454 
455 /**
456  * Fuse device instance
457  */
458 struct fuse_dev {
459 	/** Fuse connection for this device */
460 	struct fuse_conn *fc;
461 
462 	/** Processing queue */
463 	struct fuse_pqueue pq;
464 
465 	/** list entry on fc->devices */
466 	struct list_head entry;
467 };
468 
469 struct fuse_fs_context {
470 	int fd;
471 	unsigned int rootmode;
472 	kuid_t user_id;
473 	kgid_t group_id;
474 	bool is_bdev:1;
475 	bool fd_present:1;
476 	bool rootmode_present:1;
477 	bool user_id_present:1;
478 	bool group_id_present:1;
479 	bool default_permissions:1;
480 	bool allow_other:1;
481 	bool destroy:1;
482 	bool no_control:1;
483 	bool no_force_umount:1;
484 	bool no_mount_options:1;
485 	unsigned int max_read;
486 	unsigned int blksize;
487 	const char *subtype;
488 
489 	/* fuse_dev pointer to fill in, should contain NULL on entry */
490 	void **fudptr;
491 };
492 
493 /**
494  * A Fuse connection.
495  *
496  * This structure is created, when the filesystem is mounted, and is
497  * destroyed, when the client device is closed and the filesystem is
498  * unmounted.
499  */
500 struct fuse_conn {
501 	/** Lock protecting accessess to  members of this structure */
502 	spinlock_t lock;
503 
504 	/** Refcount */
505 	refcount_t count;
506 
507 	/** Number of fuse_dev's */
508 	atomic_t dev_count;
509 
510 	struct rcu_head rcu;
511 
512 	/** The user id for this mount */
513 	kuid_t user_id;
514 
515 	/** The group id for this mount */
516 	kgid_t group_id;
517 
518 	/** The pid namespace for this mount */
519 	struct pid_namespace *pid_ns;
520 
521 	/** The user namespace for this mount */
522 	struct user_namespace *user_ns;
523 
524 	/** Maximum read size */
525 	unsigned max_read;
526 
527 	/** Maximum write size */
528 	unsigned max_write;
529 
530 	/** Maxmum number of pages that can be used in a single request */
531 	unsigned int max_pages;
532 
533 	/** Input queue */
534 	struct fuse_iqueue iq;
535 
536 	/** The next unique kernel file handle */
537 	atomic64_t khctr;
538 
539 	/** rbtree of fuse_files waiting for poll events indexed by ph */
540 	struct rb_root polled_files;
541 
542 	/** Maximum number of outstanding background requests */
543 	unsigned max_background;
544 
545 	/** Number of background requests at which congestion starts */
546 	unsigned congestion_threshold;
547 
548 	/** Number of requests currently in the background */
549 	unsigned num_background;
550 
551 	/** Number of background requests currently queued for userspace */
552 	unsigned active_background;
553 
554 	/** The list of background requests set aside for later queuing */
555 	struct list_head bg_queue;
556 
557 	/** Protects: max_background, congestion_threshold, num_background,
558 	 * active_background, bg_queue, blocked */
559 	spinlock_t bg_lock;
560 
561 	/** Flag indicating that INIT reply has been received. Allocating
562 	 * any fuse request will be suspended until the flag is set */
563 	int initialized;
564 
565 	/** Flag indicating if connection is blocked.  This will be
566 	    the case before the INIT reply is received, and if there
567 	    are too many outstading backgrounds requests */
568 	int blocked;
569 
570 	/** waitq for blocked connection */
571 	wait_queue_head_t blocked_waitq;
572 
573 	/** Connection established, cleared on umount, connection
574 	    abort and device release */
575 	unsigned connected;
576 
577 	/** Connection aborted via sysfs */
578 	bool aborted;
579 
580 	/** Connection failed (version mismatch).  Cannot race with
581 	    setting other bitfields since it is only set once in INIT
582 	    reply, before any other request, and never cleared */
583 	unsigned conn_error:1;
584 
585 	/** Connection successful.  Only set in INIT */
586 	unsigned conn_init:1;
587 
588 	/** Do readpages asynchronously?  Only set in INIT */
589 	unsigned async_read:1;
590 
591 	/** Return an unique read error after abort.  Only set in INIT */
592 	unsigned abort_err:1;
593 
594 	/** Do not send separate SETATTR request before open(O_TRUNC)  */
595 	unsigned atomic_o_trunc:1;
596 
597 	/** Filesystem supports NFS exporting.  Only set in INIT */
598 	unsigned export_support:1;
599 
600 	/** write-back cache policy (default is write-through) */
601 	unsigned writeback_cache:1;
602 
603 	/** allow parallel lookups and readdir (default is serialized) */
604 	unsigned parallel_dirops:1;
605 
606 	/** handle fs handles killing suid/sgid/cap on write/chown/trunc */
607 	unsigned handle_killpriv:1;
608 
609 	/** cache READLINK responses in page cache */
610 	unsigned cache_symlinks:1;
611 
612 	/*
613 	 * The following bitfields are only for optimization purposes
614 	 * and hence races in setting them will not cause malfunction
615 	 */
616 
617 	/** Is open/release not implemented by fs? */
618 	unsigned no_open:1;
619 
620 	/** Is opendir/releasedir not implemented by fs? */
621 	unsigned no_opendir:1;
622 
623 	/** Is fsync not implemented by fs? */
624 	unsigned no_fsync:1;
625 
626 	/** Is fsyncdir not implemented by fs? */
627 	unsigned no_fsyncdir:1;
628 
629 	/** Is flush not implemented by fs? */
630 	unsigned no_flush:1;
631 
632 	/** Is setxattr not implemented by fs? */
633 	unsigned no_setxattr:1;
634 
635 	/** Is getxattr not implemented by fs? */
636 	unsigned no_getxattr:1;
637 
638 	/** Is listxattr not implemented by fs? */
639 	unsigned no_listxattr:1;
640 
641 	/** Is removexattr not implemented by fs? */
642 	unsigned no_removexattr:1;
643 
644 	/** Are posix file locking primitives not implemented by fs? */
645 	unsigned no_lock:1;
646 
647 	/** Is access not implemented by fs? */
648 	unsigned no_access:1;
649 
650 	/** Is create not implemented by fs? */
651 	unsigned no_create:1;
652 
653 	/** Is interrupt not implemented by fs? */
654 	unsigned no_interrupt:1;
655 
656 	/** Is bmap not implemented by fs? */
657 	unsigned no_bmap:1;
658 
659 	/** Is poll not implemented by fs? */
660 	unsigned no_poll:1;
661 
662 	/** Do multi-page cached writes */
663 	unsigned big_writes:1;
664 
665 	/** Don't apply umask to creation modes */
666 	unsigned dont_mask:1;
667 
668 	/** Are BSD file locking primitives not implemented by fs? */
669 	unsigned no_flock:1;
670 
671 	/** Is fallocate not implemented by fs? */
672 	unsigned no_fallocate:1;
673 
674 	/** Is rename with flags implemented by fs? */
675 	unsigned no_rename2:1;
676 
677 	/** Use enhanced/automatic page cache invalidation. */
678 	unsigned auto_inval_data:1;
679 
680 	/** Filesystem is fully reponsible for page cache invalidation. */
681 	unsigned explicit_inval_data:1;
682 
683 	/** Does the filesystem support readdirplus? */
684 	unsigned do_readdirplus:1;
685 
686 	/** Does the filesystem want adaptive readdirplus? */
687 	unsigned readdirplus_auto:1;
688 
689 	/** Does the filesystem support asynchronous direct-IO submission? */
690 	unsigned async_dio:1;
691 
692 	/** Is lseek not implemented by fs? */
693 	unsigned no_lseek:1;
694 
695 	/** Does the filesystem support posix acls? */
696 	unsigned posix_acl:1;
697 
698 	/** Check permissions based on the file mode or not? */
699 	unsigned default_permissions:1;
700 
701 	/** Allow other than the mounter user to access the filesystem ? */
702 	unsigned allow_other:1;
703 
704 	/** Does the filesystem support copy_file_range? */
705 	unsigned no_copy_file_range:1;
706 
707 	/* Send DESTROY request */
708 	unsigned int destroy:1;
709 
710 	/* Delete dentries that have gone stale */
711 	unsigned int delete_stale:1;
712 
713 	/** Do not create entry in fusectl fs */
714 	unsigned int no_control:1;
715 
716 	/** Do not allow MNT_FORCE umount */
717 	unsigned int no_force_umount:1;
718 
719 	/* Do not show mount options */
720 	unsigned int no_mount_options:1;
721 
722 	/** The number of requests waiting for completion */
723 	atomic_t num_waiting;
724 
725 	/** Negotiated minor version */
726 	unsigned minor;
727 
728 	/** Entry on the fuse_conn_list */
729 	struct list_head entry;
730 
731 	/** Device ID from super block */
732 	dev_t dev;
733 
734 	/** Dentries in the control filesystem */
735 	struct dentry *ctl_dentry[FUSE_CTL_NUM_DENTRIES];
736 
737 	/** number of dentries used in the above array */
738 	int ctl_ndents;
739 
740 	/** Key for lock owner ID scrambling */
741 	u32 scramble_key[4];
742 
743 	/** Version counter for attribute changes */
744 	atomic64_t attr_version;
745 
746 	/** Called on final put */
747 	void (*release)(struct fuse_conn *);
748 
749 	/** Super block for this connection. */
750 	struct super_block *sb;
751 
752 	/** Read/write semaphore to hold when accessing sb. */
753 	struct rw_semaphore killsb;
754 
755 	/** List of device instances belonging to this connection */
756 	struct list_head devices;
757 };
758 
759 static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb)
760 {
761 	return sb->s_fs_info;
762 }
763 
764 static inline struct fuse_conn *get_fuse_conn(struct inode *inode)
765 {
766 	return get_fuse_conn_super(inode->i_sb);
767 }
768 
769 static inline struct fuse_inode *get_fuse_inode(struct inode *inode)
770 {
771 	return container_of(inode, struct fuse_inode, inode);
772 }
773 
774 static inline u64 get_node_id(struct inode *inode)
775 {
776 	return get_fuse_inode(inode)->nodeid;
777 }
778 
779 static inline int invalid_nodeid(u64 nodeid)
780 {
781 	return !nodeid || nodeid == FUSE_ROOT_ID;
782 }
783 
784 static inline u64 fuse_get_attr_version(struct fuse_conn *fc)
785 {
786 	return atomic64_read(&fc->attr_version);
787 }
788 
789 /** Device operations */
790 extern const struct file_operations fuse_dev_operations;
791 
792 extern const struct dentry_operations fuse_dentry_operations;
793 extern const struct dentry_operations fuse_root_dentry_operations;
794 
795 /**
796  * Inode to nodeid comparison.
797  */
798 int fuse_inode_eq(struct inode *inode, void *_nodeidp);
799 
800 /**
801  * Get a filled in inode
802  */
803 struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
804 			int generation, struct fuse_attr *attr,
805 			u64 attr_valid, u64 attr_version);
806 
807 int fuse_lookup_name(struct super_block *sb, u64 nodeid, const struct qstr *name,
808 		     struct fuse_entry_out *outarg, struct inode **inode);
809 
810 /**
811  * Send FORGET command
812  */
813 void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget,
814 		       u64 nodeid, u64 nlookup);
815 
816 struct fuse_forget_link *fuse_alloc_forget(void);
817 
818 struct fuse_forget_link *fuse_dequeue_forget(struct fuse_iqueue *fiq,
819 					     unsigned int max,
820 					     unsigned int *countp);
821 
822 /*
823  * Initialize READ or READDIR request
824  */
825 struct fuse_io_args {
826 	union {
827 		struct {
828 			struct fuse_read_in in;
829 			u64 attr_ver;
830 		} read;
831 		struct {
832 			struct fuse_write_in in;
833 			struct fuse_write_out out;
834 		} write;
835 	};
836 	struct fuse_args_pages ap;
837 	struct fuse_io_priv *io;
838 	struct fuse_file *ff;
839 };
840 
841 void fuse_read_args_fill(struct fuse_io_args *ia, struct file *file, loff_t pos,
842 			 size_t count, int opcode);
843 
844 
845 /**
846  * Send OPEN or OPENDIR request
847  */
848 int fuse_open_common(struct inode *inode, struct file *file, bool isdir);
849 
850 struct fuse_file *fuse_file_alloc(struct fuse_conn *fc);
851 void fuse_file_free(struct fuse_file *ff);
852 void fuse_finish_open(struct inode *inode, struct file *file);
853 
854 void fuse_sync_release(struct fuse_inode *fi, struct fuse_file *ff, int flags);
855 
856 /**
857  * Send RELEASE or RELEASEDIR request
858  */
859 void fuse_release_common(struct file *file, bool isdir);
860 
861 /**
862  * Send FSYNC or FSYNCDIR request
863  */
864 int fuse_fsync_common(struct file *file, loff_t start, loff_t end,
865 		      int datasync, int opcode);
866 
867 /**
868  * Notify poll wakeup
869  */
870 int fuse_notify_poll_wakeup(struct fuse_conn *fc,
871 			    struct fuse_notify_poll_wakeup_out *outarg);
872 
873 /**
874  * Initialize file operations on a regular file
875  */
876 void fuse_init_file_inode(struct inode *inode);
877 
878 /**
879  * Initialize inode operations on regular files and special files
880  */
881 void fuse_init_common(struct inode *inode);
882 
883 /**
884  * Initialize inode and file operations on a directory
885  */
886 void fuse_init_dir(struct inode *inode);
887 
888 /**
889  * Initialize inode operations on a symlink
890  */
891 void fuse_init_symlink(struct inode *inode);
892 
893 /**
894  * Change attributes of an inode
895  */
896 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
897 			    u64 attr_valid, u64 attr_version);
898 
899 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
900 				   u64 attr_valid);
901 
902 /**
903  * Initialize the client device
904  */
905 int fuse_dev_init(void);
906 
907 /**
908  * Cleanup the client device
909  */
910 void fuse_dev_cleanup(void);
911 
912 int fuse_ctl_init(void);
913 void __exit fuse_ctl_cleanup(void);
914 
915 /**
916  * Simple request sending that does request allocation and freeing
917  */
918 ssize_t fuse_simple_request(struct fuse_conn *fc, struct fuse_args *args);
919 int fuse_simple_background(struct fuse_conn *fc, struct fuse_args *args,
920 			   gfp_t gfp_flags);
921 
922 /**
923  * End a finished request
924  */
925 void fuse_request_end(struct fuse_conn *fc, struct fuse_req *req);
926 
927 /* Abort all requests */
928 void fuse_abort_conn(struct fuse_conn *fc);
929 void fuse_wait_aborted(struct fuse_conn *fc);
930 
931 /**
932  * Invalidate inode attributes
933  */
934 void fuse_invalidate_attr(struct inode *inode);
935 
936 void fuse_invalidate_entry_cache(struct dentry *entry);
937 
938 void fuse_invalidate_atime(struct inode *inode);
939 
940 u64 entry_attr_timeout(struct fuse_entry_out *o);
941 void fuse_change_entry_timeout(struct dentry *entry, struct fuse_entry_out *o);
942 
943 /**
944  * Acquire reference to fuse_conn
945  */
946 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc);
947 
948 /**
949  * Initialize fuse_conn
950  */
951 void fuse_conn_init(struct fuse_conn *fc, struct user_namespace *user_ns,
952 		    const struct fuse_iqueue_ops *fiq_ops, void *fiq_priv);
953 
954 /**
955  * Release reference to fuse_conn
956  */
957 void fuse_conn_put(struct fuse_conn *fc);
958 
959 struct fuse_dev *fuse_dev_alloc_install(struct fuse_conn *fc);
960 struct fuse_dev *fuse_dev_alloc(void);
961 void fuse_dev_install(struct fuse_dev *fud, struct fuse_conn *fc);
962 void fuse_dev_free(struct fuse_dev *fud);
963 void fuse_send_init(struct fuse_conn *fc);
964 
965 /**
966  * Fill in superblock and initialize fuse connection
967  * @sb: partially-initialized superblock to fill in
968  * @ctx: mount context
969  */
970 int fuse_fill_super_common(struct super_block *sb, struct fuse_fs_context *ctx);
971 
972 /**
973  * Disassociate fuse connection from superblock and kill the superblock
974  *
975  * Calls kill_anon_super(), do not use with bdev mounts.
976  */
977 void fuse_kill_sb_anon(struct super_block *sb);
978 
979 /**
980  * Add connection to control filesystem
981  */
982 int fuse_ctl_add_conn(struct fuse_conn *fc);
983 
984 /**
985  * Remove connection from control filesystem
986  */
987 void fuse_ctl_remove_conn(struct fuse_conn *fc);
988 
989 /**
990  * Is file type valid?
991  */
992 int fuse_valid_type(int m);
993 
994 bool fuse_invalid_attr(struct fuse_attr *attr);
995 
996 /**
997  * Is current process allowed to perform filesystem operation?
998  */
999 int fuse_allow_current_process(struct fuse_conn *fc);
1000 
1001 u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id);
1002 
1003 void fuse_update_ctime(struct inode *inode);
1004 
1005 int fuse_update_attributes(struct inode *inode, struct file *file);
1006 
1007 void fuse_flush_writepages(struct inode *inode);
1008 
1009 void fuse_set_nowrite(struct inode *inode);
1010 void fuse_release_nowrite(struct inode *inode);
1011 
1012 /**
1013  * File-system tells the kernel to invalidate cache for the given node id.
1014  */
1015 int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid,
1016 			     loff_t offset, loff_t len);
1017 
1018 /**
1019  * File-system tells the kernel to invalidate parent attributes and
1020  * the dentry matching parent/name.
1021  *
1022  * If the child_nodeid is non-zero and:
1023  *    - matches the inode number for the dentry matching parent/name,
1024  *    - is not a mount point
1025  *    - is a file or oan empty directory
1026  * then the dentry is unhashed (d_delete()).
1027  */
1028 int fuse_reverse_inval_entry(struct super_block *sb, u64 parent_nodeid,
1029 			     u64 child_nodeid, struct qstr *name);
1030 
1031 int fuse_do_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
1032 		 bool isdir);
1033 
1034 /**
1035  * fuse_direct_io() flags
1036  */
1037 
1038 /** If set, it is WRITE; otherwise - READ */
1039 #define FUSE_DIO_WRITE (1 << 0)
1040 
1041 /** CUSE pass fuse_direct_io() a file which f_mapping->host is not from FUSE */
1042 #define FUSE_DIO_CUSE  (1 << 1)
1043 
1044 ssize_t fuse_direct_io(struct fuse_io_priv *io, struct iov_iter *iter,
1045 		       loff_t *ppos, int flags);
1046 long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
1047 		   unsigned int flags);
1048 long fuse_ioctl_common(struct file *file, unsigned int cmd,
1049 		       unsigned long arg, unsigned int flags);
1050 __poll_t fuse_file_poll(struct file *file, poll_table *wait);
1051 int fuse_dev_release(struct inode *inode, struct file *file);
1052 
1053 bool fuse_write_update_size(struct inode *inode, loff_t pos);
1054 
1055 int fuse_flush_times(struct inode *inode, struct fuse_file *ff);
1056 int fuse_write_inode(struct inode *inode, struct writeback_control *wbc);
1057 
1058 int fuse_do_setattr(struct dentry *dentry, struct iattr *attr,
1059 		    struct file *file);
1060 
1061 void fuse_set_initialized(struct fuse_conn *fc);
1062 
1063 void fuse_unlock_inode(struct inode *inode, bool locked);
1064 bool fuse_lock_inode(struct inode *inode);
1065 
1066 int fuse_setxattr(struct inode *inode, const char *name, const void *value,
1067 		  size_t size, int flags);
1068 ssize_t fuse_getxattr(struct inode *inode, const char *name, void *value,
1069 		      size_t size);
1070 ssize_t fuse_listxattr(struct dentry *entry, char *list, size_t size);
1071 int fuse_removexattr(struct inode *inode, const char *name);
1072 extern const struct xattr_handler *fuse_xattr_handlers[];
1073 extern const struct xattr_handler *fuse_acl_xattr_handlers[];
1074 extern const struct xattr_handler *fuse_no_acl_xattr_handlers[];
1075 
1076 struct posix_acl;
1077 struct posix_acl *fuse_get_acl(struct inode *inode, int type);
1078 int fuse_set_acl(struct inode *inode, struct posix_acl *acl, int type);
1079 
1080 
1081 /* readdir.c */
1082 int fuse_readdir(struct file *file, struct dir_context *ctx);
1083 
1084 /**
1085  * Return the number of bytes in an arguments list
1086  */
1087 unsigned int fuse_len_args(unsigned int numargs, struct fuse_arg *args);
1088 
1089 /**
1090  * Get the next unique ID for a request
1091  */
1092 u64 fuse_get_unique(struct fuse_iqueue *fiq);
1093 void fuse_free_conn(struct fuse_conn *fc);
1094 
1095 #endif /* _FS_FUSE_I_H */
1096