fuse_i.h 24.7 KB
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/*
  FUSE: Filesystem in Userspace
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  Copyright (C) 2001-2008  Miklos Szeredi <miklos@szeredi.hu>
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  This program can be distributed under the terms of the GNU GPL.
  See the file COPYING.
*/

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#ifndef _FS_FUSE_I_H
#define _FS_FUSE_I_H

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#include <linux/fuse.h>
#include <linux/fs.h>
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#include <linux/mount.h>
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#include <linux/wait.h>
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/mm.h>
#include <linux/backing-dev.h>
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#include <linux/mutex.h>
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#include <linux/rwsem.h>
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#include <linux/rbtree.h>
#include <linux/poll.h>
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#include <linux/workqueue.h>
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#include <linux/kref.h>
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#include <linux/xattr.h>
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#include <linux/pid_namespace.h>
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#include <linux/refcount.h>
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#include <linux/user_namespace.h>
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/** Max number of pages that can be used in a single read request */
#define FUSE_MAX_PAGES_PER_REQ 32

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/** Bias for fi->writectr, meaning new writepages must not be sent */
#define FUSE_NOWRITE INT_MIN

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/** It could be as large as PATH_MAX, but would that have any uses? */
#define FUSE_NAME_MAX 1024

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/** Number of dentries for each connection in the control filesystem */
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#define FUSE_CTL_NUM_DENTRIES 5
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/** Number of page pointers embedded in fuse_req */
#define FUSE_REQ_INLINE_PAGES 1

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/** List of active connections */
extern struct list_head fuse_conn_list;

/** Global mutex protecting fuse_conn_list and the control filesystem */
extern struct mutex fuse_mutex;
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/** Module parameters */
extern unsigned max_user_bgreq;
extern unsigned max_user_congthresh;

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/* One forget request */
struct fuse_forget_link {
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	struct fuse_forget_one forget_one;
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	struct fuse_forget_link *next;
};

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/** FUSE inode */
struct fuse_inode {
	/** Inode data */
	struct inode inode;

	/** Unique ID, which identifies the inode between userspace
	 * and kernel */
	u64 nodeid;

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	/** Number of lookups on this inode */
	u64 nlookup;

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	/** The request used for sending the FORGET message */
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	struct fuse_forget_link *forget;
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	/** Time in jiffies until the file attributes are valid */
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	u64 i_time;
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	/** The sticky bit in inode->i_mode may have been removed, so
	    preserve the original mode */
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	umode_t orig_i_mode;
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	/** 64 bit inode number */
	u64 orig_ino;

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	/** Version of last attribute change */
	u64 attr_version;
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	/** Files usable in writepage.  Protected by fc->lock */
	struct list_head write_files;
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	/** Writepages pending on truncate or fsync */
	struct list_head queued_writes;

	/** Number of sent writes, a negative bias (FUSE_NOWRITE)
	 * means more writes are blocked */
	int writectr;

	/** Waitq for writepage completion */
	wait_queue_head_t page_waitq;

	/** List of writepage requestst (pending or sent) */
	struct list_head writepages;
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	/* readdir cache */
	struct {
		/* true if fully cached */
		bool cached;

		/* size of cache */
		loff_t size;

		/* position at end of cache (position of next entry) */
		loff_t pos;

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		/* version of the cache */
		u64 version;

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		/* protects above fields */
		spinlock_t lock;
	} rdc;

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	/** Miscellaneous bits describing inode state */
	unsigned long state;
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	/** Lock for serializing lookup and readdir for back compatibility*/
	struct mutex mutex;
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};

/** FUSE inode state bits */
enum {
	/** Advise readdirplus  */
	FUSE_I_ADVISE_RDPLUS,
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	/** Initialized with readdirplus */
	FUSE_I_INIT_RDPLUS,
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	/** An operation changing file size is in progress  */
	FUSE_I_SIZE_UNSTABLE,
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};

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struct fuse_conn;

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/** FUSE specific file data */
struct fuse_file {
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	/** Fuse connection for this file */
	struct fuse_conn *fc;

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	/** Request reserved for flush and release */
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	struct fuse_req *reserved_req;
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	/** Kernel file handle guaranteed to be unique */
	u64 kh;

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	/** File handle used by userspace */
	u64 fh;
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	/** Node id of this file */
	u64 nodeid;

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	/** Refcount */
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	refcount_t count;
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	/** FOPEN_* flags returned by open */
	u32 open_flags;

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	/** Entry on inode's write_files list */
	struct list_head write_entry;
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	/* Readdir related */
	struct {
		/*
		 * Protects below fields against (crazy) parallel readdir on
		 * same open file.  Uncontended in the normal case.
		 */
		struct mutex lock;

		/* Dir stream position */
		loff_t pos;

		/* Offset in cache */
		loff_t cache_off;
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		/* Version of cache we are reading */
		u64 version;

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	} readdir;

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	/** RB node to be linked on fuse_conn->polled_files */
	struct rb_node polled_node;

	/** Wait queue head for poll */
	wait_queue_head_t poll_wait;
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	/** Has flock been performed on this file? */
	bool flock:1;
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};

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/** One input argument of a request */
struct fuse_in_arg {
	unsigned size;
	const void *value;
};

/** The request input */
struct fuse_in {
	/** The request header */
	struct fuse_in_header h;

	/** True if the data for the last argument is in req->pages */
	unsigned argpages:1;

	/** Number of arguments */
	unsigned numargs;

	/** Array of arguments */
	struct fuse_in_arg args[3];
};

/** One output argument of a request */
struct fuse_arg {
	unsigned size;
	void *value;
};

/** The request output */
struct fuse_out {
	/** Header returned from userspace */
	struct fuse_out_header h;

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	/*
	 * The following bitfields are not changed during the request
	 * processing
	 */

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	/** Last argument is variable length (can be shorter than
	    arg->size) */
	unsigned argvar:1;

	/** Last argument is a list of pages to copy data to */
	unsigned argpages:1;

	/** Zero partially or not copied pages */
	unsigned page_zeroing:1;

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	/** Pages may be replaced with new ones */
	unsigned page_replace:1;

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	/** Number or arguments */
	unsigned numargs;

	/** Array of arguments */
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	struct fuse_arg args[2];
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};

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/** FUSE page descriptor */
struct fuse_page_desc {
	unsigned int length;
	unsigned int offset;
};

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struct fuse_args {
	struct {
		struct {
			uint32_t opcode;
			uint64_t nodeid;
		} h;
		unsigned numargs;
		struct fuse_in_arg args[3];

	} in;
	struct {
		unsigned argvar:1;
		unsigned numargs;
		struct fuse_arg args[2];
	} out;
};

#define FUSE_ARGS(args) struct fuse_args args = {}

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/** The request IO state (for asynchronous processing) */
struct fuse_io_priv {
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	struct kref refcnt;
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	int async;
	spinlock_t lock;
	unsigned reqs;
	ssize_t bytes;
	size_t size;
	__u64 offset;
	bool write;
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	bool should_dirty;
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	int err;
	struct kiocb *iocb;
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	struct completion *done;
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	bool blocking;
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};

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#define FUSE_IO_PRIV_SYNC(i) \
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{					\
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	.refcnt = KREF_INIT(1),		\
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	.async = 0,			\
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	.iocb = i,			\
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}

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/**
 * Request flags
 *
 * FR_ISREPLY:		set if the request has reply
 * FR_FORCE:		force sending of the request even if interrupted
 * FR_BACKGROUND:	request is sent in the background
 * FR_WAITING:		request is counted as "waiting"
 * FR_ABORTED:		the request was aborted
 * FR_INTERRUPTED:	the request has been interrupted
 * FR_LOCKED:		data is being copied to/from the request
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 * FR_PENDING:		request is not yet in userspace
 * FR_SENT:		request is in userspace, waiting for an answer
 * FR_FINISHED:		request is finished
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 * FR_PRIVATE:		request is on private list
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 */
enum fuse_req_flag {
	FR_ISREPLY,
	FR_FORCE,
	FR_BACKGROUND,
	FR_WAITING,
	FR_ABORTED,
	FR_INTERRUPTED,
	FR_LOCKED,
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	FR_PENDING,
	FR_SENT,
	FR_FINISHED,
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	FR_PRIVATE,
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};

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/**
 * A request to the client
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 *
 * .waitq.lock protects the following fields:
 *   - FR_ABORTED
 *   - FR_LOCKED (may also be modified under fc->lock, tested under both)
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 */
struct fuse_req {
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	/** This can be on either pending processing or io lists in
	    fuse_conn */
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	struct list_head list;

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	/** Entry on the interrupts list  */
	struct list_head intr_entry;

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	/** refcount */
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	refcount_t count;
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	/* Request flags, updated with test/set/clear_bit() */
	unsigned long flags;
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	/** The request input */
	struct fuse_in in;

	/** The request output */
	struct fuse_out out;

	/** Used to wake up the task waiting for completion of request*/
	wait_queue_head_t waitq;

	/** Data for asynchronous requests */
	union {
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		struct {
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			struct fuse_release_in in;
			struct inode *inode;
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		} release;
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		struct fuse_init_in init_in;
		struct fuse_init_out init_out;
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		struct cuse_init_in cuse_init_in;
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		struct {
			struct fuse_read_in in;
			u64 attr_ver;
		} read;
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		struct {
			struct fuse_write_in in;
			struct fuse_write_out out;
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			struct fuse_req *next;
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		} write;
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		struct fuse_notify_retrieve_in retrieve_in;
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	} misc;

	/** page vector */
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	struct page **pages;

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	/** page-descriptor vector */
	struct fuse_page_desc *page_descs;

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	/** size of the 'pages' array */
	unsigned max_pages;

	/** inline page vector */
	struct page *inline_pages[FUSE_REQ_INLINE_PAGES];
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	/** inline page-descriptor vector */
	struct fuse_page_desc inline_page_descs[FUSE_REQ_INLINE_PAGES];

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	/** number of pages in vector */
	unsigned num_pages;

	/** File used in the request (or NULL) */
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	struct fuse_file *ff;
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	/** Inode used in the request or NULL */
	struct inode *inode;

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	/** AIO control block */
	struct fuse_io_priv *io;

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	/** Link on fi->writepages */
	struct list_head writepages_entry;

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	/** Request completion callback */
	void (*end)(struct fuse_conn *, struct fuse_req *);
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	/** Request is stolen from fuse_file->reserved_req */
	struct file *stolen_file;
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};

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struct fuse_iqueue {
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	/** Connection established */
	unsigned connected;

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	/** Readers of the connection are waiting on this */
	wait_queue_head_t waitq;

	/** The next unique request id */
	u64 reqctr;

	/** The list of pending requests */
	struct list_head pending;

	/** Pending interrupts */
	struct list_head interrupts;

	/** Queue of pending forgets */
	struct fuse_forget_link forget_list_head;
	struct fuse_forget_link *forget_list_tail;

	/** Batching of FORGET requests (positive indicates FORGET batch) */
	int forget_batch;

	/** O_ASYNC requests */
	struct fasync_struct *fasync;
};

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#define FUSE_PQ_HASH_BITS 8
#define FUSE_PQ_HASH_SIZE (1 << FUSE_PQ_HASH_BITS)

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struct fuse_pqueue {
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	/** Connection established */
	unsigned connected;

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	/** Lock protecting accessess to  members of this structure */
	spinlock_t lock;

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	/** Hash table of requests being processed */
	struct list_head *processing;
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	/** The list of requests under I/O */
	struct list_head io;
};

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/**
 * Fuse device instance
 */
struct fuse_dev {
	/** Fuse connection for this device */
	struct fuse_conn *fc;

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	/** Processing queue */
	struct fuse_pqueue pq;

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	/** list entry on fc->devices */
	struct list_head entry;
};

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/**
 * A Fuse connection.
 *
 * This structure is created, when the filesystem is mounted, and is
 * destroyed, when the client device is closed and the filesystem is
 * unmounted.
 */
struct fuse_conn {
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	/** Lock protecting accessess to  members of this structure */
	spinlock_t lock;

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	/** Refcount */
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	refcount_t count;
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	/** Number of fuse_dev's */
	atomic_t dev_count;

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	struct rcu_head rcu;

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	/** The user id for this mount */
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	kuid_t user_id;
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	/** The group id for this mount */
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	kgid_t group_id;
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	/** The pid namespace for this mount */
	struct pid_namespace *pid_ns;

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	/** The user namespace for this mount */
	struct user_namespace *user_ns;

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	/** Maximum read size */
	unsigned max_read;

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	/** Maximum write size */
	unsigned max_write;

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	/** Input queue */
	struct fuse_iqueue iq;
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	/** The next unique kernel file handle */
	u64 khctr;

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	/** rbtree of fuse_files waiting for poll events indexed by ph */
	struct rb_root polled_files;

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	/** Maximum number of outstanding background requests */
	unsigned max_background;

	/** Number of background requests at which congestion starts */
	unsigned congestion_threshold;

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	/** Number of requests currently in the background */
	unsigned num_background;

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	/** Number of background requests currently queued for userspace */
	unsigned active_background;

	/** The list of background requests set aside for later queuing */
	struct list_head bg_queue;

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	/** Protects: max_background, congestion_threshold, num_background,
	 * active_background, bg_queue, blocked */
	spinlock_t bg_lock;

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	/** Flag indicating that INIT reply has been received. Allocating
	 * any fuse request will be suspended until the flag is set */
	int initialized;

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	/** Flag indicating if connection is blocked.  This will be
	    the case before the INIT reply is received, and if there
	    are too many outstading backgrounds requests */
	int blocked;

	/** waitq for blocked connection */
	wait_queue_head_t blocked_waitq;
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	/** waitq for reserved requests */
	wait_queue_head_t reserved_req_waitq;
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	/** Connection established, cleared on umount, connection
	    abort and device release */
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	unsigned connected;
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	/** Connection aborted via sysfs */
	bool aborted;

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	/** Connection failed (version mismatch).  Cannot race with
	    setting other bitfields since it is only set once in INIT
	    reply, before any other request, and never cleared */
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	unsigned conn_error:1;
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	/** Connection successful.  Only set in INIT */
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	unsigned conn_init:1;
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	/** Do readpages asynchronously?  Only set in INIT */
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	unsigned async_read:1;
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	/** Return an unique read error after abort.  Only set in INIT */
	unsigned abort_err:1;

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	/** Do not send separate SETATTR request before open(O_TRUNC)  */
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	unsigned atomic_o_trunc:1;
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	/** Filesystem supports NFS exporting.  Only set in INIT */
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	unsigned export_support:1;
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	/** write-back cache policy (default is write-through) */
	unsigned writeback_cache:1;

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	/** allow parallel lookups and readdir (default is serialized) */
	unsigned parallel_dirops:1;

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	/** handle fs handles killing suid/sgid/cap on write/chown/trunc */
	unsigned handle_killpriv:1;

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	/*
	 * The following bitfields are only for optimization purposes
	 * and hence races in setting them will not cause malfunction
	 */

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	/** Is open/release not implemented by fs? */
	unsigned no_open:1;

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	/** Is fsync not implemented by fs? */
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	unsigned no_fsync:1;
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	/** Is fsyncdir not implemented by fs? */
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	unsigned no_fsyncdir:1;
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	/** Is flush not implemented by fs? */
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	unsigned no_flush:1;
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	/** Is setxattr not implemented by fs? */
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	unsigned no_setxattr:1;
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	/** Is getxattr not implemented by fs? */
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	unsigned no_getxattr:1;
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	/** Is listxattr not implemented by fs? */
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	unsigned no_listxattr:1;
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	/** Is removexattr not implemented by fs? */
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	unsigned no_removexattr:1;
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	/** Are posix file locking primitives not implemented by fs? */
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	unsigned no_lock:1;
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	/** Is access not implemented by fs? */
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	unsigned no_access:1;
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	/** Is create not implemented by fs? */
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	unsigned no_create:1;
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	/** Is interrupt not implemented by fs? */
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	unsigned no_interrupt:1;
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	/** Is bmap not implemented by fs? */
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	unsigned no_bmap:1;
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	/** Is poll not implemented by fs? */
	unsigned no_poll:1;

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	/** Do multi-page cached writes */
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	unsigned big_writes:1;
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	/** Don't apply umask to creation modes */
	unsigned dont_mask:1;

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	/** Are BSD file locking primitives not implemented by fs? */
	unsigned no_flock:1;

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	/** Is fallocate not implemented by fs? */
	unsigned no_fallocate:1;

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	/** Is rename with flags implemented by fs? */
	unsigned no_rename2:1;

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	/** Use enhanced/automatic page cache invalidation. */
	unsigned auto_inval_data:1;

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	/** Does the filesystem support readdirplus? */
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	unsigned do_readdirplus:1;

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	/** Does the filesystem want adaptive readdirplus? */
	unsigned readdirplus_auto:1;

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	/** Does the filesystem support asynchronous direct-IO submission? */
	unsigned async_dio:1;

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	/** Is lseek not implemented by fs? */
	unsigned no_lseek:1;

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	/** Does the filesystem support posix acls? */
	unsigned posix_acl:1;

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	/** Check permissions based on the file mode or not? */
	unsigned default_permissions:1;

	/** Allow other than the mounter user to access the filesystem ? */
	unsigned allow_other:1;

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	/** Does the filesystem support copy_file_range? */
	unsigned no_copy_file_range:1;

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	/** The number of requests waiting for completion */
	atomic_t num_waiting;

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	/** Negotiated minor version */
	unsigned minor;

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	/** Entry on the fuse_conn_list */
	struct list_head entry;

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	/** Device ID from super block */
	dev_t dev;
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	/** Dentries in the control filesystem */
	struct dentry *ctl_dentry[FUSE_CTL_NUM_DENTRIES];

	/** number of dentries used in the above array */
	int ctl_ndents;
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	/** Key for lock owner ID scrambling */
	u32 scramble_key[4];
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	/** Reserved request for the DESTROY message */
	struct fuse_req *destroy_req;
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	/** Version counter for attribute changes */
	u64 attr_version;
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	/** Called on final put */
	void (*release)(struct fuse_conn *);
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	/** Super block for this connection. */
	struct super_block *sb;

	/** Read/write semaphore to hold when accessing sb. */
	struct rw_semaphore killsb;
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	/** List of device instances belonging to this connection */
	struct list_head devices;
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};

static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb)
{
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	return sb->s_fs_info;
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}

static inline struct fuse_conn *get_fuse_conn(struct inode *inode)
{
	return get_fuse_conn_super(inode->i_sb);
}

static inline struct fuse_inode *get_fuse_inode(struct inode *inode)
{
	return container_of(inode, struct fuse_inode, inode);
}

static inline u64 get_node_id(struct inode *inode)
{
	return get_fuse_inode(inode)->nodeid;
}

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static inline int invalid_nodeid(u64 nodeid)
{
	return !nodeid || nodeid == FUSE_ROOT_ID;
}

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/** Device operations */
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extern const struct file_operations fuse_dev_operations;
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extern const struct dentry_operations fuse_dentry_operations;
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extern const struct dentry_operations fuse_root_dentry_operations;
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/**
 * Inode to nodeid comparison.
 */
int fuse_inode_eq(struct inode *inode, void *_nodeidp);

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/**
 * Get a filled in inode
 */
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struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
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			int generation, struct fuse_attr *attr,
			u64 attr_valid, u64 attr_version);
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int fuse_lookup_name(struct super_block *sb, u64 nodeid, const struct qstr *name,
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		     struct fuse_entry_out *outarg, struct inode **inode);

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/**
 * Send FORGET command
 */
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void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget,
		       u64 nodeid, u64 nlookup);

struct fuse_forget_link *fuse_alloc_forget(void);
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/* Used by READDIRPLUS */
void fuse_force_forget(struct file *file, u64 nodeid);

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/**
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 * Initialize READ or READDIR request
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 */
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void fuse_read_fill(struct fuse_req *req, struct file *file,
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		    loff_t pos, size_t count, int opcode);
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/**
 * Send OPEN or OPENDIR request
 */
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int fuse_open_common(struct inode *inode, struct file *file, bool isdir);
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struct fuse_file *fuse_file_alloc(struct fuse_conn *fc);
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void fuse_file_free(struct fuse_file *ff);
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void fuse_finish_open(struct inode *inode, struct file *file);
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void fuse_sync_release(struct fuse_file *ff, int flags);
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/**
 * Send RELEASE or RELEASEDIR request
 */
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void fuse_release_common(struct file *file, int opcode);
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/**
 * Send FSYNC or FSYNCDIR request
 */
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int fuse_fsync_common(struct file *file, loff_t start, loff_t end,
		      int datasync, int isdir);
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/**
 * Notify poll wakeup
 */
int fuse_notify_poll_wakeup(struct fuse_conn *fc,
			    struct fuse_notify_poll_wakeup_out *outarg);

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/**
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 * Initialize file operations on a regular file
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 */
void fuse_init_file_inode(struct inode *inode);

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/**
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 * Initialize inode operations on regular files and special files
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 */
void fuse_init_common(struct inode *inode);

/**
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 * Initialize inode and file operations on a directory
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 */
void fuse_init_dir(struct inode *inode);

/**
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 * Initialize inode operations on a symlink
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 */
void fuse_init_symlink(struct inode *inode);

/**
 * Change attributes of an inode
 */
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void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
			    u64 attr_valid, u64 attr_version);
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void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
				   u64 attr_valid);

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/**
 * Initialize the client device
 */
int fuse_dev_init(void);

/**
 * Cleanup the client device
 */
void fuse_dev_cleanup(void);

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int fuse_ctl_init(void);
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void __exit fuse_ctl_cleanup(void);
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/**
 * Allocate a request
 */
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struct fuse_req *fuse_request_alloc(unsigned npages);
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struct fuse_req *fuse_request_alloc_nofs(unsigned npages);
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/**
 * Free a request
 */
void fuse_request_free(struct fuse_req *req);

/**
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 * Get a request, may fail with -ENOMEM,
 * caller should specify # elements in req->pages[] explicitly
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 */
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struct fuse_req *fuse_get_req(struct fuse_conn *fc, unsigned npages);
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struct fuse_req *fuse_get_req_for_background(struct fuse_conn *fc,
					     unsigned npages);
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/*
 * Increment reference count on request
 */
void __fuse_get_request(struct fuse_req *req);

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/**
 * Gets a requests for a file operation, always succeeds
 */
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struct fuse_req *fuse_get_req_nofail_nopages(struct fuse_conn *fc,
					     struct file *file);
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/**
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 * Decrement reference count of a request.  If count goes to zero free
 * the request.
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 */
void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req);

/**
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 * Send a request (synchronous)
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 */
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void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req);
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/**
 * Simple request sending that does request allocation and freeing
 */
ssize_t fuse_simple_request(struct fuse_conn *fc, struct fuse_args *args);

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/**
 * Send a request in the background
 */
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void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req);
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bool fuse_request_queue_background(struct fuse_conn *fc, struct fuse_req *req);
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/* Abort all requests */
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void fuse_abort_conn(struct fuse_conn *fc, bool is_abort);
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void fuse_wait_aborted(struct fuse_conn *fc);
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/**
 * Invalidate inode attributes
 */
void fuse_invalidate_attr(struct inode *inode);
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void fuse_invalidate_entry_cache(struct dentry *entry);

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void fuse_invalidate_atime(struct inode *inode);

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u64 entry_attr_timeout(struct fuse_entry_out *o);
void fuse_change_entry_timeout(struct dentry *entry, struct fuse_entry_out *o);

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/**
 * Acquire reference to fuse_conn
 */
struct fuse_conn *fuse_conn_get(struct fuse_conn *fc);

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/**
 * Initialize fuse_conn
 */
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void fuse_conn_init(struct fuse_conn *fc, struct user_namespace *user_ns);
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/**
 * Release reference to fuse_conn
 */
void fuse_conn_put(struct fuse_conn *fc);

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struct fuse_dev *fuse_dev_alloc(struct fuse_conn *fc);
void fuse_dev_free(struct fuse_dev *fud);

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/**
 * Add connection to control filesystem
 */
int fuse_ctl_add_conn(struct fuse_conn *fc);

/**
 * Remove connection from control filesystem
 */
void fuse_ctl_remove_conn(struct fuse_conn *fc);
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/**
 * Is file type valid?
 */
int fuse_valid_type(int m);
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/**
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 * Is current process allowed to perform filesystem operation?
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 */
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int fuse_allow_current_process(struct fuse_conn *fc);
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u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id);
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void fuse_update_ctime(struct inode *inode);

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int fuse_update_attributes(struct inode *inode, struct file *file);
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void fuse_flush_writepages(struct inode *inode);

void fuse_set_nowrite(struct inode *inode);
void fuse_release_nowrite(struct inode *inode);
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u64 fuse_get_attr_version(struct fuse_conn *fc);
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/**
 * File-system tells the kernel to invalidate cache for the given node id.
 */
int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid,
			     loff_t offset, loff_t len);

/**
 * File-system tells the kernel to invalidate parent attributes and
 * the dentry matching parent/name.
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 *
 * If the child_nodeid is non-zero and:
 *    - matches the inode number for the dentry matching parent/name,
 *    - is not a mount point
 *    - is a file or oan empty directory
 * then the dentry is unhashed (d_delete()).
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 */
int fuse_reverse_inval_entry(struct super_block *sb, u64 parent_nodeid,
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int fuse_do_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
		 bool isdir);
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/**
 * fuse_direct_io() flags
 */

/** If set, it is WRITE; otherwise - READ */
#define FUSE_DIO_WRITE (1 << 0)

/** CUSE pass fuse_direct_io() a file which f_mapping->host is not from FUSE */
#define FUSE_DIO_CUSE  (1 << 1)

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ssize_t fuse_direct_io(struct fuse_io_priv *io, struct iov_iter *iter,
		       loff_t *ppos, int flags);
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long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
		   unsigned int flags);
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long fuse_ioctl_common(struct file *file, unsigned int cmd,
		       unsigned long arg, unsigned int flags);
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__poll_t fuse_file_poll(struct file *file, poll_table *wait);
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int fuse_dev_release(struct inode *inode, struct file *file);

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bool fuse_write_update_size(struct inode *inode, loff_t pos);

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int fuse_flush_times(struct inode *inode, struct fuse_file *ff);
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int fuse_write_inode(struct inode *inode, struct writeback_control *wbc);
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int fuse_do_setattr(struct dentry *dentry, struct iattr *attr,
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		    struct file *file);

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void fuse_set_initialized(struct fuse_conn *fc);

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void fuse_unlock_inode(struct inode *inode, bool locked);
bool fuse_lock_inode(struct inode *inode);
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int fuse_setxattr(struct inode *inode, const char *name, const void *value,
		  size_t size, int flags);
ssize_t fuse_getxattr(struct inode *inode, const char *name, void *value,
		      size_t size);
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ssize_t fuse_listxattr(struct dentry *entry, char *list, size_t size);
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int fuse_removexattr(struct inode *inode, const char *name);
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extern const struct xattr_handler *fuse_xattr_handlers[];
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extern const struct xattr_handler *fuse_acl_xattr_handlers[];
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extern const struct xattr_handler *fuse_no_acl_xattr_handlers[];
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struct posix_acl;
struct posix_acl *fuse_get_acl(struct inode *inode, int type);
int fuse_set_acl(struct inode *inode, struct posix_acl *acl, int type);
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/* readdir.c */
int fuse_readdir(struct file *file, struct dir_context *ctx);

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#endif /* _FS_FUSE_I_H */