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/*
FUSE: Filesystem in Userspace
Copyright (C) 2001-2008 Miklos Szeredi <miklos@szeredi.hu>
This program can be distributed under the terms of the GNU GPL.
See the file COPYING.
*/
#ifndef _FS_FUSE_I_H
#define _FS_FUSE_I_H
#include <linux/fuse.h>
#include <linux/fs.h>
#include <linux/mount.h>
#include <linux/wait.h>
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/mm.h>
#include <linux/backing-dev.h>
#include <linux/mutex.h>
#include <linux/rwsem.h>
#include <linux/rbtree.h>
#include <linux/poll.h>
#include <linux/workqueue.h>
/** Max number of pages that can be used in a single read request */
#define FUSE_MAX_PAGES_PER_REQ 32
/** Bias for fi->writectr, meaning new writepages must not be sent */
#define FUSE_NOWRITE INT_MIN
/** It could be as large as PATH_MAX, but would that have any uses? */
#define FUSE_NAME_MAX 1024
/** Number of dentries for each connection in the control filesystem */
#define FUSE_CTL_NUM_DENTRIES 5
/** If the FUSE_DEFAULT_PERMISSIONS flag is given, the filesystem
module will check permissions based on the file mode. Otherwise no
permission checking is done in the kernel */
#define FUSE_DEFAULT_PERMISSIONS (1 << 0)
/** If the FUSE_ALLOW_OTHER flag is given, then not only the user
doing the mount will be allowed to access the filesystem */
#define FUSE_ALLOW_OTHER (1 << 1)
/** 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;
/** Module parameters */
extern unsigned max_user_bgreq;
extern unsigned max_user_congthresh;
/* One forget request */
struct fuse_forget_link {
struct fuse_forget_one forget_one;
struct fuse_forget_link *next;
};
/** FUSE inode */
struct fuse_inode {
/** Inode data */
struct inode inode;
/** Unique ID, which identifies the inode between userspace
* and kernel */
u64 nodeid;
/** Number of lookups on this inode */
u64 nlookup;
/** The request used for sending the FORGET message */
struct fuse_forget_link *forget;
/** Time in jiffies until the file attributes are valid */
u64 i_time;
/** The sticky bit in inode->i_mode may have been removed, so
preserve the original mode */
umode_t orig_i_mode;
/** Version of last attribute change */
u64 attr_version;
/** Files usable in writepage. Protected by fc->lock */
struct list_head write_files;
/** 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;
};
struct fuse_conn;
/** FUSE specific file data */
struct fuse_file {
/** Fuse connection for this file */
struct fuse_conn *fc;
/** Request reserved for flush and release */
struct fuse_req *reserved_req;
/** Kernel file handle guaranteed to be unique */
u64 kh;
/** File handle used by userspace */
u64 fh;
/** Node id of this file */
u64 nodeid;
/** Refcount */
atomic_t count;
/** FOPEN_* flags returned by open */
u32 open_flags;
/** Entry on inode's write_files list */
struct list_head write_entry;
/** 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;
/** Has flock been performed on this file? */
bool flock:1;
};
/** 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;
/*
* The following bitfields are not changed during the request
* processing
*/
/** 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;
/** Pages may be replaced with new ones */
unsigned page_replace:1;
/** Number or arguments */
unsigned numargs;
/** Array of arguments */
struct fuse_arg args[3];
};
/** The request state */
enum fuse_req_state {
FUSE_REQ_INIT = 0,
FUSE_REQ_PENDING,
FUSE_REQ_READING,
FUSE_REQ_SENT,
FUSE_REQ_WRITING,
FUSE_REQ_FINISHED
};
/**
* A request to the client
*/
struct fuse_req {
/** This can be on either pending processing or io lists in
fuse_conn */
struct list_head list;
/** Entry on the interrupts list */
struct list_head intr_entry;
/** refcount */
atomic_t count;
/** Unique ID for the interrupt request */
u64 intr_unique;
/*
* The following bitfields are either set once before the
* request is queued or setting/clearing them is protected by
* fuse_conn->lock
*/
/** True if the request has reply */
unsigned isreply:1;
/** Force sending of the request even if interrupted */
unsigned force:1;
/** The request was aborted */
unsigned aborted:1;
/** Request is sent in the background */
unsigned background:1;
/** The request has been interrupted */
unsigned interrupted:1;
/** Data is being copied to/from the request */
unsigned locked:1;
/** Request is counted as "waiting" */
unsigned waiting:1;
/** State of the request */
enum fuse_req_state state;
/** 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 {
struct {
union {
struct fuse_release_in in;
struct work_struct work;
};
struct path path;
} release;
struct fuse_init_in init_in;
struct fuse_init_out init_out;
struct cuse_init_in cuse_init_in;
struct {
struct fuse_read_in in;
u64 attr_ver;
} read;
struct {
struct fuse_write_in in;
struct fuse_write_out out;
} write;
struct fuse_notify_retrieve_in retrieve_in;
struct fuse_lk_in lk_in;
} misc;
/** page vector */
struct page *pages[FUSE_MAX_PAGES_PER_REQ];
/** number of pages in vector */
unsigned num_pages;
/** offset of data on first page */
unsigned page_offset;
/** File used in the request (or NULL) */
struct fuse_file *ff;
/** Inode used in the request or NULL */
struct inode *inode;
/** Link on fi->writepages */
struct list_head writepages_entry;
/** Request completion callback */
void (*end)(struct fuse_conn *, struct fuse_req *);
/** Request is stolen from fuse_file->reserved_req */
struct file *stolen_file;
};
/**
* 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 {
/** Lock protecting accessess to members of this structure */
spinlock_t lock;
/** Mutex protecting against directory alias creation */
struct mutex inst_mutex;
/** Refcount */
atomic_t count;
/** The user id for this mount */
uid_t user_id;
/** The group id for this mount */
gid_t group_id;
/** The fuse mount flags for this mount */
unsigned flags;
/** Maximum read size */
unsigned max_read;
/** Maximum write size */
unsigned max_write;
/** Readers of the connection are waiting on this */
wait_queue_head_t waitq;
/** The list of pending requests */
struct list_head pending;
/** The list of requests being processed */
struct list_head processing;
/** The list of requests under I/O */
struct list_head io
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