1/* 2 * JFFS -- Journalling Flash File System, Linux implementation. 3 * 4 * Copyright (C) 1999, 2000 Axis Communications AB. 5 * 6 * Created by Finn Hakansson <finn@axis.com>. 7 * 8 * This is free software; you can redistribute it and/or modify it 9 * under the terms of the GNU General Public License as published by 10 * the Free Software Foundation; either version 2 of the License, or 11 * (at your option) any later version. 12 * 13 * $Id: jffs.h,v 1.1.1.1 2008/10/15 03:27:30 james26_jang Exp $ 14 * 15 * Ported to Linux 2.3.x and MTD: 16 * Copyright (C) 2000 Alexander Larsson (alex@cendio.se), Cendio Systems AB 17 * 18 */ 19 20#ifndef __LINUX_JFFS_H__ 21#define __LINUX_JFFS_H__ 22 23#include <linux/types.h> 24#include <linux/completion.h> 25 26#define JFFS_VERSION_STRING "1.0" 27 28/* This is a magic number that is used as an identification number for 29 this file system. It is written to the super_block structure. */ 30#define JFFS_MAGIC_SB_BITMASK 0x07c0 /* 1984 */ 31 32/* This is a magic number that every on-flash raw inode begins with. */ 33#define JFFS_MAGIC_BITMASK 0x34383931 /* "1984" */ 34 35/* These two bitmasks are the valid ones for the flash memories we have 36 for the moment. */ 37#define JFFS_EMPTY_BITMASK 0xffffffff 38#define JFFS_DIRTY_BITMASK 0x00000000 39 40/* This is the inode number of the root node. */ 41#define JFFS_MIN_INO 1 42 43/* How many slots in the file hash table should we have? */ 44#define JFFS_HASH_SIZE 40 45 46/* Don't use more than 254 bytes as the maximum allowed length of a file's 47 name due to errors that could occur during the scanning of the flash 48 memory. In fact, a name length of 255 or 0xff, could be the result of 49 an uncompleted write. For instance, if a raw inode is written to the 50 flash memory and there is a power lossage just before the length of 51 the name is written, the length 255 would be interpreted as an illegal 52 value. */ 53#define JFFS_MAX_NAME_LEN 254 54 55/* Commands for ioctl(). */ 56#define JFFS_IOCTL_MAGIC 't' 57#define JFFS_PRINT_HASH _IO(JFFS_IOCTL_MAGIC, 90) 58#define JFFS_PRINT_TREE _IO(JFFS_IOCTL_MAGIC, 91) 59#define JFFS_GET_STATUS _IO(JFFS_IOCTL_MAGIC, 92) 60 61#define JFFS_MODIFY_INODE 0x01 62#define JFFS_MODIFY_NAME 0x02 63#define JFFS_MODIFY_DATA 0x04 64#define JFFS_MODIFY_EXIST 0x08 65 66struct jffs_control; 67 68/* The JFFS raw inode structure: Used for storage on physical media. */ 69/* Perhaps the uid, gid, atime, mtime and ctime members should have 70 more space due to future changes in the Linux kernel. Anyhow, since 71 a user of this filesystem probably have to fix a large number of 72 other things, we have decided to not be forward compatible. */ 73struct jffs_raw_inode 74{ 75 __u32 magic; /* A constant magic number. */ 76 __u32 ino; /* Inode number. */ 77 __u32 pino; /* Parent's inode number. */ 78 __u32 version; /* Version number. */ 79 __u32 mode; /* The file's type or mode. */ 80 __u16 uid; /* The file's owner. */ 81 __u16 gid; /* The file's group. */ 82 __u32 atime; /* Last access time. */ 83 __u32 mtime; /* Last modification time. */ 84 __u32 ctime; /* Creation time. */ 85 __u32 offset; /* Where to begin to write. */ 86 __u32 dsize; /* Size of the node's data. */ 87 __u32 rsize; /* How much are going to be replaced? */ 88 __u8 nsize; /* Name length. */ 89 __u8 nlink; /* Number of links. */ 90 __u8 spare : 6; /* For future use. */ 91 __u8 rename : 1; /* Rename to a name of an already existing file? */ 92 __u8 deleted : 1; /* Has this file been deleted? */ 93 __u8 accurate; /* The inode is obsolete if accurate == 0. */ 94 __u32 dchksum; /* Checksum for the data. */ 95 __u16 nchksum; /* Checksum for the name. */ 96 __u16 chksum; /* Checksum for the raw inode. */ 97}; 98 99/* Define the offset of the accurate byte in struct jffs_raw_inode. */ 100#define JFFS_RAW_INODE_ACCURATE_OFFSET (sizeof(struct jffs_raw_inode) \ 101 - 2 * sizeof(__u32) - sizeof(__u8)) 102 103/* Define the offset of the chksum member in struct jffs_raw_inode. */ 104#define JFFS_RAW_INODE_CHKSUM_OFFSET (sizeof(struct jffs_raw_inode) \ 105 - sizeof(__u16)) 106 107/* Define the offset of the dchksum member in struct jffs_raw_inode. */ 108#define JFFS_RAW_INODE_DCHKSUM_OFFSET (sizeof(struct jffs_raw_inode) \ 109 - sizeof(__u16) - sizeof(__u16) \ 110 - sizeof(__u32)) 111 112 113/* The RAM representation of the node. The names of pointers to 114 jffs_nodes are very often just called `n' in the source code. */ 115struct jffs_node 116{ 117 __u32 ino; /* Inode number. */ 118 __u32 version; /* Version number. */ 119 __u32 data_offset; /* Logic location of the data to insert. */ 120 __u32 data_size; /* The amount of data this node inserts. */ 121 __u32 removed_size; /* The amount of data that this node removes. */ 122 __u32 fm_offset; /* Physical location of the data in the actual 123 flash memory data chunk. */ 124 __u8 name_size; /* Size of the name. */ 125 struct jffs_fm *fm; /* Physical memory information. */ 126 struct jffs_node *version_prev; 127 struct jffs_node *version_next; 128 struct jffs_node *range_prev; 129 struct jffs_node *range_next; 130}; 131 132 133/* The RAM representation of a file (plain files, directories, 134 links, etc.). Pointers to jffs_files are normally named `f' 135 in the JFFS source code. */ 136struct jffs_file 137{ 138 __u32 ino; /* Inode number. */ 139 __u32 pino; /* Parent's inode number. */ 140 __u32 mode; /* file_type, mode */ 141 __u16 uid; /* owner */ 142 __u16 gid; /* group */ 143 __u32 atime; /* Last access time. */ 144 __u32 mtime; /* Last modification time. */ 145 __u32 ctime; /* Creation time. */ 146 __u8 nsize; /* Name length. */ 147 __u8 nlink; /* Number of links. */ 148 __u8 deleted; /* Has this file been deleted? */ 149 char *name; /* The name of this file; NULL-terminated. */ 150 __u32 size; /* The total size of the file's data. */ 151 __u32 highest_version; /* The highest version number of this file. */ 152 struct jffs_control *c; 153 struct jffs_file *parent; /* Reference to the parent directory. */ 154 struct jffs_file *children; /* Always NULL for plain files. */ 155 struct jffs_file *sibling_prev; /* Siblings in the same directory. */ 156 struct jffs_file *sibling_next; 157 struct list_head hash; /* hash list. */ 158 struct jffs_node *range_head; /* The final data. */ 159 struct jffs_node *range_tail; /* The first data. */ 160 struct jffs_node *version_head; /* The youngest node. */ 161 struct jffs_node *version_tail; /* The oldest node. */ 162}; 163 164 165/* This is just a definition of a simple list used for keeping track of 166 files deleted due to a rename. This list is only used during the 167 mounting of the file system and only if there have been rename operations 168 earlier. */ 169struct jffs_delete_list 170{ 171 __u32 ino; 172 struct jffs_delete_list *next; 173}; 174 175 176/* A struct for the overall file system control. Pointers to 177 jffs_control structs are named `c' in the source code. */ 178struct jffs_control 179{ 180 struct super_block *sb; /* Reference to the VFS super block. */ 181 struct jffs_file *root; /* The root directory file. */ 182 struct list_head *hash; /* Hash table for finding files by ino. */ 183 struct jffs_fmcontrol *fmc; /* Flash memory control structure. */ 184 __u32 hash_len; /* The size of the hash table. */ 185 __u32 next_ino; /* Next inode number to use for new files. */ 186 __u16 building_fs; /* Is the file system being built right now? */ 187 struct jffs_delete_list *delete_list; /* Track deleted files. */ 188 pid_t thread_pid; /* GC thread's PID */ 189 struct task_struct *gc_task; /* GC task struct */ 190 struct completion gc_thread_comp; /* GC thread exit mutex */ 191 __u32 gc_minfree_threshold; /* GC trigger thresholds */ 192 __u32 gc_maxdirty_threshold; 193}; 194 195 196/* Used to inform about flash status. */ 197struct jffs_flash_status 198{ 199 __u32 size; 200 __u32 used; 201 __u32 dirty; 202 __u32 begin; 203 __u32 end; 204}; 205 206/* This stuff could be used for finding memory leaks. */ 207#define JFFS_MEMORY_DEBUG 0 208 209extern long no_jffs_node; 210extern long no_jffs_file; 211#if defined(JFFS_MEMORY_DEBUG) && JFFS_MEMORY_DEBUG 212extern long no_jffs_control; 213extern long no_jffs_raw_inode; 214extern long no_jffs_node_ref; 215extern long no_jffs_fm; 216extern long no_jffs_fmcontrol; 217extern long no_hash; 218extern long no_name; 219#define DJM(x) x 220#else 221#define DJM(x) 222#endif 223 224#endif /* __LINUX_JFFS_H__ */ 225