Blame |
Last modification |
View Log
| RSS feed
/*
* JFFS -- Journalling Flash File System, Linux implementation.
*
* Copyright (C) 1999, 2000 Axis Communications AB.
*
* Created by Finn Hakansson <finn@axis.com>.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* $Id: jffs.h,v 1.1 2004-01-28 15:25:47 giacomo Exp $
*
* Ported to Linux 2.3.x and MTD:
* Copyright (C) 2000 Alexander Larsson (alex@cendio.se), Cendio Systems AB
*
*/
#ifndef __LINUX_JFFS_H__
#define __LINUX_JFFS_H__
#include <linux/types.h>
#include <linux/completion.h>
#define JFFS_VERSION_STRING "1.0"
/* This is a magic number that is used as an identification number for
this file system. It is written to the super_block structure. */
#define JFFS_MAGIC_SB_BITMASK 0x07c0 /* 1984 */
/* This is a magic number that every on-flash raw inode begins with. */
#define JFFS_MAGIC_BITMASK 0x34383931 /* "1984" */
/* These two bitmasks are the valid ones for the flash memories we have
for the moment. */
#define JFFS_EMPTY_BITMASK 0xffffffff
#define JFFS_DIRTY_BITMASK 0x00000000
/* This is the inode number of the root node. */
#define JFFS_MIN_INO 1
/* How many slots in the file hash table should we have? */
#define JFFS_HASH_SIZE 40
/* Don't use more than 254 bytes as the maximum allowed length of a file's
name due to errors that could occur during the scanning of the flash
memory. In fact, a name length of 255 or 0xff, could be the result of
an uncompleted write. For instance, if a raw inode is written to the
flash memory and there is a power lossage just before the length of
the name is written, the length 255 would be interpreted as an illegal
value. */
#define JFFS_MAX_NAME_LEN 254
/* Commands for ioctl(). */
#define JFFS_IOCTL_MAGIC 't'
#define JFFS_PRINT_HASH _IO(JFFS_IOCTL_MAGIC, 90)
#define JFFS_PRINT_TREE _IO(JFFS_IOCTL_MAGIC, 91)
#define JFFS_GET_STATUS _IO(JFFS_IOCTL_MAGIC, 92)
/* XXX: This is something that we should try to get rid of in the future. */
#define JFFS_MODIFY_INODE 0x01
#define JFFS_MODIFY_NAME 0x02
#define JFFS_MODIFY_DATA 0x04
#define JFFS_MODIFY_EXIST 0x08
struct jffs_control;
/* The JFFS raw inode structure: Used for storage on physical media. */
/* Perhaps the uid, gid, atime, mtime and ctime members should have
more space due to future changes in the Linux kernel. Anyhow, since
a user of this filesystem probably have to fix a large number of
other things, we have decided to not be forward compatible. */
struct jffs_raw_inode
{
__u32 magic; /* A constant magic number. */
__u32 ino; /* Inode number. */
__u32 pino; /* Parent's inode number. */
__u32 version; /* Version number. */
__u32 mode; /* The file's type or mode. */
__u16 uid; /* The file's owner. */
__u16 gid; /* The file's group. */
__u32 atime; /* Last access time. */
__u32 mtime; /* Last modification time. */
__u32 ctime; /* Creation time. */
__u32 offset; /* Where to begin to write. */
__u32 dsize; /* Size of the node's data. */
__u32 rsize; /* How much are going to be replaced? */
__u8 nsize; /* Name length. */
__u8 nlink; /* Number of links. */
__u8 spare : 6; /* For future use. */
__u8 rename : 1; /* Rename to a name of an already existing file? */
__u8 deleted : 1; /* Has this file been deleted? */
__u8 accurate; /* The inode is obsolete if accurate == 0. */
__u32 dchksum; /* Checksum for the data. */
__u16 nchksum; /* Checksum for the name. */
__u16 chksum; /* Checksum for the raw inode. */
};
/* Define the offset of the accurate byte in struct jffs_raw_inode. */
#define JFFS_RAW_INODE_ACCURATE_OFFSET (sizeof(struct jffs_raw_inode) \
- 2 * sizeof(__u32) - sizeof(__u8))
/* Define the offset of the chksum member in struct jffs_raw_inode. */
#define JFFS_RAW_INODE_CHKSUM_OFFSET (sizeof(struct jffs_raw_inode) \
- sizeof(__u16))
/* Define the offset of the dchksum member in struct jffs_raw_inode. */
#define JFFS_RAW_INODE_DCHKSUM_OFFSET (sizeof(struct jffs_raw_inode) \
- sizeof(__u16) - sizeof(__u16) \
- sizeof(__u32))
/* The RAM representation of the node. The names of pointers to
jffs_nodes are very often just called `n' in the source code. */
struct jffs_node
{
__u32 ino; /* Inode number. */
__u32 version; /* Version number. */
__u32 data_offset; /* Logic location of the data to insert. */
__u32 data_size; /* The amount of data this node inserts. */
__u32 removed_size; /* The amount of data that this node removes. */
__u32 fm_offset; /* Physical location of the data in the actual
flash memory data chunk. */
__u8 name_size; /* Size of the name. */
struct jffs_fm *fm; /* Physical memory information. */
struct jffs_node *version_prev;
struct jffs_node *version_next;
struct jffs_node *range_prev;
struct jffs_node *range_next;
};
/* The RAM representation of a file (plain files, directories,
links, etc.). Pointers to jffs_files are normally named `f'
in the JFFS source code. */
struct jffs_file
{
__u32 ino; /* Inode number. */
__u32 pino; /* Parent's inode number. */
__u32 mode; /* file_type, mode */
__u16 uid; /* owner */
__u16 gid; /* group */
__u32 atime; /* Last access time. */
__u32 mtime; /* Last modification time. */
__u32 ctime; /* Creation time. */
__u8 nsize; /* Name length. */
__u8 nlink; /* Number of links. */
__u8 deleted; /* Has this file been deleted? */
char *name; /* The name of this file; NULL-terminated. */
__u32 size; /* The total size of the file's data. */
__u32 highest_version; /* The highest version number of this file. */
struct jffs_control *c;
struct jffs_file *parent; /* Reference to the parent directory. */
struct jffs_file *children; /* Always NULL for plain files. */
struct jffs_file *sibling_prev; /* Siblings in the same directory. */
struct jffs_file *sibling_next;
struct list_head hash; /* hash list. */
struct jffs_node *range_head; /* The final data. */
struct jffs_node *range_tail; /* The first data. */
struct jffs_node *version_head; /* The youngest node. */
struct jffs_node *version_tail; /* The oldest node. */
};
/* This is just a definition of a simple list used for keeping track of
files deleted due to a rename. This list is only used during the
mounting of the file system and only if there have been rename operations
earlier. */
struct jffs_delete_list
{
__u32 ino;
struct jffs_delete_list *next;
};
/* A struct for the overall file system control. Pointers to
jffs_control structs are named `c' in the source code. */
struct jffs_control
{
struct super_block *sb; /* Reference to the VFS super block. */
struct jffs_file *root; /* The root directory file. */
struct list_head *hash; /* Hash table for finding files by ino. */
struct jffs_fmcontrol *fmc; /* Flash memory control structure. */
__u32 hash_len; /* The size of the hash table. */
__u32 next_ino; /* Next inode number to use for new files. */
__u16 building_fs; /* Is the file system being built right now? */
struct jffs_delete_list *delete_list; /* Track deleted files. */
pid_t thread_pid; /* GC thread's PID */
struct task_struct *gc_task; /* GC task struct */
struct completion gc_thread_comp; /* GC thread exit mutex */
__u32 gc_minfree_threshold; /* GC trigger thresholds */
__u32 gc_maxdirty_threshold;
};
/* Used to inform about flash status. */
struct jffs_flash_status
{
__u32 size;
__u32 used;
__u32 dirty;
__u32 begin;
__u32 end;
};
/* This stuff could be used for finding memory leaks. */
#define JFFS_MEMORY_DEBUG 0
extern long no_jffs_node;
extern long no_jffs_file;
#if defined(JFFS_MEMORY_DEBUG) && JFFS_MEMORY_DEBUG
extern long no_jffs_control;
extern long no_jffs_raw_inode;
extern long no_jffs_node_ref;
extern long no_jffs_fm;
extern long no_jffs_fmcontrol;
extern long no_hash;
extern long no_name;
#define DJM(x) x
#else
#define DJM(x)
#endif
#endif /* __LINUX_JFFS_H__ */