705 lines
16 KiB
C
705 lines
16 KiB
C
/*
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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.
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See the file COPYING.
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*/
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#ifndef _FS_FUSE_I_H
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#define _FS_FUSE_I_H
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#include <linux/fuse.h>
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#include <linux/fs.h>
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#include <linux/mount.h>
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#include <linux/wait.h>
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#include <linux/list.h>
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#include <linux/spinlock.h>
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#include <linux/mm.h>
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#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>
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#include <linux/poll.h>
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/** Max number of pages that can be used in a single read request */
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#define FUSE_MAX_PAGES_PER_REQ 32
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/** Maximum number of outstanding background requests */
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#define FUSE_MAX_BACKGROUND 12
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/** Congestion starts at 75% of maximum */
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#define FUSE_CONGESTION_THRESHOLD (FUSE_MAX_BACKGROUND * 75 / 100)
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/** Bias for fi->writectr, meaning new writepages must not be sent */
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#define FUSE_NOWRITE INT_MIN
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/** It could be as large as PATH_MAX, but would that have any uses? */
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#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 3
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/** If the FUSE_DEFAULT_PERMISSIONS flag is given, the filesystem
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module will check permissions based on the file mode. Otherwise no
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permission checking is done in the kernel */
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#define FUSE_DEFAULT_PERMISSIONS (1 << 0)
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/** If the FUSE_ALLOW_OTHER flag is given, then not only the user
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doing the mount will be allowed to access the filesystem */
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#define FUSE_ALLOW_OTHER (1 << 1)
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/** List of active connections */
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extern struct list_head fuse_conn_list;
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/** Global mutex protecting fuse_conn_list and the control filesystem */
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extern struct mutex fuse_mutex;
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/** FUSE inode */
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struct fuse_inode {
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/** Inode data */
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struct inode inode;
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/** Unique ID, which identifies the inode between userspace
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* and kernel */
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u64 nodeid;
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/** Number of lookups on this inode */
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u64 nlookup;
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/** The request used for sending the FORGET message */
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struct fuse_req *forget_req;
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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
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preserve the original mode */
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mode_t orig_i_mode;
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/** Version of last attribute change */
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u64 attr_version;
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/** Files usable in writepage. Protected by fc->lock */
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struct list_head write_files;
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/** Writepages pending on truncate or fsync */
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struct list_head queued_writes;
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/** Number of sent writes, a negative bias (FUSE_NOWRITE)
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* means more writes are blocked */
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int writectr;
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/** Waitq for writepage completion */
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wait_queue_head_t page_waitq;
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/** List of writepage requestst (pending or sent) */
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struct list_head writepages;
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};
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struct fuse_conn;
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/** FUSE specific file data */
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struct fuse_file {
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/** Fuse connection for this file */
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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 */
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u64 kh;
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/** File handle used by userspace */
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u64 fh;
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/** Node id of this file */
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u64 nodeid;
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/** Refcount */
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atomic_t count;
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/** FOPEN_* flags returned by open */
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u32 open_flags;
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/** Entry on inode's write_files list */
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struct list_head write_entry;
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/** RB node to be linked on fuse_conn->polled_files */
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struct rb_node polled_node;
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/** Wait queue head for poll */
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wait_queue_head_t poll_wait;
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};
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/** One input argument of a request */
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struct fuse_in_arg {
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unsigned size;
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const void *value;
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};
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/** The request input */
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struct fuse_in {
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/** The request header */
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struct fuse_in_header h;
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/** True if the data for the last argument is in req->pages */
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unsigned argpages:1;
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/** Number of arguments */
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unsigned numargs;
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/** Array of arguments */
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struct fuse_in_arg args[3];
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};
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/** One output argument of a request */
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struct fuse_arg {
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unsigned size;
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void *value;
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};
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/** The request output */
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struct fuse_out {
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/** Header returned from userspace */
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struct fuse_out_header h;
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/*
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* The following bitfields are not changed during the request
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* processing
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*/
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/** Last argument is variable length (can be shorter than
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arg->size) */
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unsigned argvar:1;
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/** Last argument is a list of pages to copy data to */
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unsigned argpages:1;
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/** Zero partially or not copied pages */
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unsigned page_zeroing:1;
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/** Number or arguments */
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unsigned numargs;
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/** Array of arguments */
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struct fuse_arg args[3];
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};
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/** The request state */
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enum fuse_req_state {
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FUSE_REQ_INIT = 0,
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FUSE_REQ_PENDING,
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FUSE_REQ_READING,
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FUSE_REQ_SENT,
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FUSE_REQ_WRITING,
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FUSE_REQ_FINISHED
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};
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/**
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* A request to the client
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*/
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struct fuse_req {
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/** This can be on either pending processing or io lists in
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fuse_conn */
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struct list_head list;
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/** Entry on the interrupts list */
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struct list_head intr_entry;
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/** refcount */
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atomic_t count;
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/** Unique ID for the interrupt request */
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u64 intr_unique;
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/*
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* The following bitfields are either set once before the
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* request is queued or setting/clearing them is protected by
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* fuse_conn->lock
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*/
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/** True if the request has reply */
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unsigned isreply:1;
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/** Force sending of the request even if interrupted */
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unsigned force:1;
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/** The request was aborted */
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unsigned aborted:1;
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/** Request is sent in the background */
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unsigned background:1;
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/** The request has been interrupted */
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unsigned interrupted:1;
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/** Data is being copied to/from the request */
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unsigned locked:1;
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/** Request is counted as "waiting" */
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unsigned waiting:1;
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/** State of the request */
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enum fuse_req_state state;
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/** The request input */
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struct fuse_in in;
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/** The request output */
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struct fuse_out out;
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/** Used to wake up the task waiting for completion of request*/
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wait_queue_head_t waitq;
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/** Data for asynchronous requests */
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union {
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struct fuse_forget_in forget_in;
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struct {
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struct fuse_release_in in;
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struct path path;
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} release;
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struct fuse_init_in init_in;
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struct fuse_init_out init_out;
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struct {
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struct fuse_read_in in;
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u64 attr_ver;
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} read;
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struct {
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struct fuse_write_in in;
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struct fuse_write_out out;
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} write;
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struct fuse_lk_in lk_in;
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} misc;
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/** page vector */
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struct page *pages[FUSE_MAX_PAGES_PER_REQ];
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/** number of pages in vector */
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unsigned num_pages;
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/** offset of data on first page */
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unsigned page_offset;
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/** 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 */
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struct inode *inode;
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/** Link on fi->writepages */
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struct list_head writepages_entry;
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/** Request completion callback */
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void (*end)(struct fuse_conn *, struct fuse_req *);
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/** Request is stolen from fuse_file->reserved_req */
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struct file *stolen_file;
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};
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/**
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* A Fuse connection.
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*
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* This structure is created, when the filesystem is mounted, and is
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* destroyed, when the client device is closed and the filesystem is
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* unmounted.
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*/
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struct fuse_conn {
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/** Lock protecting accessess to members of this structure */
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spinlock_t lock;
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/** Mutex protecting against directory alias creation */
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struct mutex inst_mutex;
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/** Refcount */
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atomic_t count;
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/** The user id for this mount */
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uid_t user_id;
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/** The group id for this mount */
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gid_t group_id;
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/** The fuse mount flags for this mount */
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unsigned flags;
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/** Maximum read size */
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unsigned max_read;
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/** Maximum write size */
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unsigned max_write;
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/** Readers of the connection are waiting on this */
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wait_queue_head_t waitq;
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/** The list of pending requests */
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struct list_head pending;
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/** The list of requests being processed */
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struct list_head processing;
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/** The list of requests under I/O */
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struct list_head io;
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/** The next unique kernel file handle */
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u64 khctr;
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/** rbtree of fuse_files waiting for poll events indexed by ph */
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struct rb_root polled_files;
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/** Number of requests currently in the background */
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unsigned num_background;
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/** Number of background requests currently queued for userspace */
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unsigned active_background;
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/** The list of background requests set aside for later queuing */
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struct list_head bg_queue;
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/** Pending interrupts */
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struct list_head interrupts;
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/** Flag indicating if connection is blocked. This will be
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the case before the INIT reply is received, and if there
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are too many outstading backgrounds requests */
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int blocked;
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/** waitq for blocked connection */
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wait_queue_head_t blocked_waitq;
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/** waitq for reserved requests */
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wait_queue_head_t reserved_req_waitq;
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/** The next unique request id */
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u64 reqctr;
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/** Connection established, cleared on umount, connection
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abort and device release */
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unsigned connected;
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/** Connection failed (version mismatch). Cannot race with
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setting other bitfields since it is only set once in INIT
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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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/** 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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/*
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* The following bitfields are only for optimization purposes
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* and hence races in setting them will not cause malfunction
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*/
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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 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? */
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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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/** The number of requests waiting for completion */
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atomic_t num_waiting;
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/** Negotiated minor version */
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unsigned minor;
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/** Backing dev info */
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struct backing_dev_info bdi;
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/** Entry on the fuse_conn_list */
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struct list_head entry;
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/** Device ID from super block */
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dev_t dev;
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/** Dentries in the control filesystem */
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struct dentry *ctl_dentry[FUSE_CTL_NUM_DENTRIES];
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/** number of dentries used in the above array */
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int ctl_ndents;
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/** O_ASYNC requests */
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struct fasync_struct *fasync;
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/** Key for lock owner ID scrambling */
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u32 scramble_key[4];
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/** Reserved request for the DESTROY message */
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struct fuse_req *destroy_req;
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/** Version counter for attribute changes */
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u64 attr_version;
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/** Called on final put */
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void (*release)(struct fuse_conn *);
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};
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static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb)
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{
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return sb->s_fs_info;
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}
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static inline struct fuse_conn *get_fuse_conn(struct inode *inode)
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{
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return get_fuse_conn_super(inode->i_sb);
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}
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static inline struct fuse_inode *get_fuse_inode(struct inode *inode)
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{
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return container_of(inode, struct fuse_inode, inode);
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}
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static inline u64 get_node_id(struct inode *inode)
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{
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return get_fuse_inode(inode)->nodeid;
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}
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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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/**
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* Get a filled in inode
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*/
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struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
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int generation, struct fuse_attr *attr,
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u64 attr_valid, u64 attr_version);
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int fuse_lookup_name(struct super_block *sb, u64 nodeid, struct qstr *name,
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struct fuse_entry_out *outarg, struct inode **inode);
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/**
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* Send FORGET command
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*/
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void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req,
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u64 nodeid, u64 nlookup);
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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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/**
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* Send OPEN or OPENDIR request
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*/
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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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struct fuse_file *fuse_file_get(struct fuse_file *ff);
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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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/**
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* Send RELEASE or RELEASEDIR request
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*/
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void fuse_release_common(struct file *file, int opcode);
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/**
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* Send FSYNC or FSYNCDIR request
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*/
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int fuse_fsync_common(struct file *file, struct dentry *de, int datasync,
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int isdir);
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/**
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* Notify poll wakeup
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*/
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int fuse_notify_poll_wakeup(struct fuse_conn *fc,
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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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*/
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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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*/
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void fuse_init_common(struct inode *inode);
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/**
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* Initialize inode and file operations on a directory
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*/
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void fuse_init_dir(struct inode *inode);
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/**
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* Initialize inode operations on a symlink
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*/
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void fuse_init_symlink(struct inode *inode);
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/**
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* Change attributes of an inode
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*/
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void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
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u64 attr_valid, u64 attr_version);
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void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
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u64 attr_valid);
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void fuse_truncate(struct address_space *mapping, loff_t offset);
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/**
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* Initialize the client device
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*/
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int fuse_dev_init(void);
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/**
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* Cleanup the client device
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*/
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void fuse_dev_cleanup(void);
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int fuse_ctl_init(void);
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void fuse_ctl_cleanup(void);
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/**
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* Allocate a request
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*/
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struct fuse_req *fuse_request_alloc(void);
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struct fuse_req *fuse_request_alloc_nofs(void);
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/**
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* Free a request
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*/
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void fuse_request_free(struct fuse_req *req);
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/**
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* Get a request, may fail with -ENOMEM
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*/
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struct fuse_req *fuse_get_req(struct fuse_conn *fc);
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/**
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* Gets a requests for a file operation, always succeeds
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*/
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struct fuse_req *fuse_get_req_nofail(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
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* the request.
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*/
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void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req);
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/**
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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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/**
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* Send a request with no reply
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*/
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void fuse_request_send_noreply(struct fuse_conn *fc, struct fuse_req *req);
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/**
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* Send a request in the background
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*/
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void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req);
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void fuse_request_send_background_locked(struct fuse_conn *fc,
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struct fuse_req *req);
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/* Abort all requests */
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void fuse_abort_conn(struct fuse_conn *fc);
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/**
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* Invalidate inode attributes
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|
*/
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void fuse_invalidate_attr(struct inode *inode);
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void fuse_invalidate_entry_cache(struct dentry *entry);
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/**
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* Acquire reference to fuse_conn
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*/
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struct fuse_conn *fuse_conn_get(struct fuse_conn *fc);
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/**
|
|
* Initialize fuse_conn
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*/
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int fuse_conn_init(struct fuse_conn *fc, struct super_block *sb);
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/**
|
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* Release reference to fuse_conn
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|
*/
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void fuse_conn_put(struct fuse_conn *fc);
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/**
|
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* Add connection to control filesystem
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|
*/
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int fuse_ctl_add_conn(struct fuse_conn *fc);
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|
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/**
|
|
* Remove connection from control filesystem
|
|
*/
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void fuse_ctl_remove_conn(struct fuse_conn *fc);
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|
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/**
|
|
* Is file type valid?
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|
*/
|
|
int fuse_valid_type(int m);
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|
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/**
|
|
* Is task allowed to perform filesystem operation?
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|
*/
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int fuse_allow_task(struct fuse_conn *fc, struct task_struct *task);
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|
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u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id);
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|
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int fuse_update_attributes(struct inode *inode, struct kstat *stat,
|
|
struct file *file, bool *refreshed);
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void fuse_flush_writepages(struct inode *inode);
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void fuse_set_nowrite(struct inode *inode);
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void fuse_release_nowrite(struct inode *inode);
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u64 fuse_get_attr_version(struct fuse_conn *fc);
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#endif /* _FS_FUSE_I_H */
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