path: root/fs/fuse/fuse_i.h

/*
  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

#ifndef pr_fmt
# define pr_fmt(fmt) "fuse: " fmt
#endif

#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>
#include <linux/kref.h>
#include <linux/xattr.h>
#include <linux/pid_namespace.h>
#include <linux/refcount.h>
#include <linux/user_namespace.h>

/** Default max number of pages that can be used in a single read request */
#define FUSE_DEFAULT_MAX_PAGES_PER_REQ 32

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

/** Maximum length of a filename, not including terminating null */

/* maximum, small enough for FUSE_MIN_READ_BUFFER*/
#define FUSE_NAME_LOW_MAX 1024
/* maximum, but needs a request buffer > FUSE_MIN_READ_BUFFER */
#define FUSE_NAME_MAX (PATH_MAX - 1)

/** Number of dentries for each connection in the control filesystem */
#define FUSE_CTL_NUM_DENTRIES 5

/* Frequency (in seconds) of request timeout checks, if opted into */
#define FUSE_TIMEOUT_TIMER_FREQ 15

/** Frequency (in jiffies) of request timeout checks, if opted into */
extern const unsigned long fuse_timeout_timer_freq;

/** Maximum of max_pages received in init_out */
extern unsigned int fuse_max_pages_limit;
/*
 * Default timeout (in seconds) for the server to reply to a request
 * before the connection is aborted, if no timeout was specified on mount.
 */
extern unsigned int fuse_default_req_timeout;
/*
 * Max timeout (in seconds) for the server to reply to a request before
 * the connection is aborted.
 */
extern unsigned int fuse_max_req_timeout;

/** 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 int max_user_bgreq;
extern unsigned int max_user_congthresh;

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

/* Submount lookup tracking */
struct fuse_submount_lookup {
	/** Refcount */
	refcount_t count;

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

	/** The request used for sending the FORGET message */
	struct fuse_forget_link *forget;
};

/** Container for data related to mapping to backing file */
struct fuse_backing {
	struct file *file;
	struct cred *cred;

	/** refcount */
	refcount_t count;
	struct rcu_head rcu;
};

/** 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;

	/* Which attributes are invalid */
	u32 inval_mask;

	/** The sticky bit in inode->i_mode may have been removed, so
	    preserve the original mode */
	umode_t orig_i_mode;

	/* Cache birthtime */
	struct timespec64 i_btime;

	/** 64 bit inode number */
	u64 orig_ino;

	/** Version of last attribute change */
	u64 attr_version;

	union {
		/* read/write io cache (regular file only) */
		struct {
			/* Files usable in writepage.  Protected by fi->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;

			/** Number of files/maps using page cache */
			int iocachectr;

			/* Waitq for writepage completion */
			wait_queue_head_t page_waitq;

			/* waitq for direct-io completion */
			wait_queue_head_t direct_io_waitq;
		};

		/* readdir cache (directory only) */
		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;

			/* version of the cache */
			u64 version;

			/* modification time of directory when cache was
			 * started */
			struct timespec64 mtime;

			/* iversion of directory when cache was started */
			u64 iversion;

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

	/** Miscellaneous bits describing inode state */
	unsigned long state;

	/** Lock for serializing lookup and readdir for back compatibility*/
	struct mutex mutex;

	/** Lock to protect write related fields */
	spinlock_t lock;

#ifdef CONFIG_FUSE_DAX
	/*