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 1.20 2001/09/18 21:33:37 dwmw2 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 /* XXX: This is something that we should try to get rid of in the future. */ 62 #define JFFS_MODIFY_INODE 0x01 63 #define JFFS_MODIFY_NAME 0x02 64 #define JFFS_MODIFY_DATA 0x04 65 #define JFFS_MODIFY_EXIST 0x08 66 67 struct jffs_control; 68 69 /* The JFFS raw inode structure: Used for storage on physical media. */ 70 /* Perhaps the uid, gid, atime, mtime and ctime members should have 71 more space due to future changes in the Linux kernel. Anyhow, since 72 a user of this filesystem probably have to fix a large number of 73 other things, we have decided to not be forward compatible. */ 74 struct jffs_raw_inode 75 { 76 __u32 magic; /* A constant magic number. */ 77 __u32 ino; /* Inode number. */ 78 __u32 pino; /* Parent's inode number. */ 79 __u32 version; /* Version number. */ 80 __u32 mode; /* The file's type or mode. */ 81 __u16 uid; /* The file's owner. */ 82 __u16 gid; /* The file's group. */ 83 __u32 atime; /* Last access time. */ 84 __u32 mtime; /* Last modification time. */ 85 __u32 ctime; /* Creation time. */ 86 __u32 offset; /* Where to begin to write. */ 87 __u32 dsize; /* Size of the node's data. */ 88 __u32 rsize; /* How much are going to be replaced? */ 89 __u8 nsize; /* Name length. */ 90 __u8 nlink; /* Number of links. */ 91 __u8 spare : 6; /* For future use. */ 92 __u8 rename : 1; /* Rename to a name of an already existing file? */ 93 __u8 deleted : 1; /* Has this file been deleted? */ 94 __u8 accurate; /* The inode is obsolete if accurate == 0. */ 95 __u32 dchksum; /* Checksum for the data. */ 96 __u16 nchksum; /* Checksum for the name. */ 97 __u16 chksum; /* Checksum for the raw inode. */ 98 }; 99 100 /* Define the offset of the accurate byte in struct jffs_raw_inode. */ 101 #define JFFS_RAW_INODE_ACCURATE_OFFSET (sizeof(struct jffs_raw_inode) \ 102 - 2 * sizeof(__u32) - sizeof(__u8)) 103 104 /* Define the offset of the chksum member in struct jffs_raw_inode. */ 105 #define JFFS_RAW_INODE_CHKSUM_OFFSET (sizeof(struct jffs_raw_inode) \ 106 - sizeof(__u16)) 107 108 /* Define the offset of the dchksum member in struct jffs_raw_inode. */ 109 #define JFFS_RAW_INODE_DCHKSUM_OFFSET (sizeof(struct jffs_raw_inode) \ 110 - sizeof(__u16) - sizeof(__u16) \ 111 - sizeof(__u32)) 112 113 114 /* The RAM representation of the node. The names of pointers to 115 jffs_nodes are very often just called `n' in the source code. */ 116 struct jffs_node 117 { 118 __u32 ino; /* Inode number. */ 119 __u32 version; /* Version number. */ 120 __u32 data_offset; /* Logic location of the data to insert. */ 121 __u32 data_size; /* The amount of data this node inserts. */ 122 __u32 removed_size; /* The amount of data that this node removes. */ 123 __u32 fm_offset; /* Physical location of the data in the actual 124 flash memory data chunk. */ 125 __u8 name_size; /* Size of the name. */ 126 struct jffs_fm *fm; /* Physical memory information. */ 127 struct jffs_node *version_prev; 128 struct jffs_node *version_next; 129 struct jffs_node *range_prev; 130 struct jffs_node *range_next; 131 }; 132 133 134 /* The RAM representation of a file (plain files, directories, 135 links, etc.). Pointers to jffs_files are normally named `f' 136 in the JFFS source code. */ 137 struct jffs_file 138 { 139 __u32 ino; /* Inode number. */ 140 __u32 pino; /* Parent's inode number. */ 141 __u32 mode; /* file_type, mode */ 142 __u16 uid; /* owner */ 143 __u16 gid; /* group */ 144 __u32 atime; /* Last access time. */ 145 __u32 mtime; /* Last modification time. */ 146 __u32 ctime; /* Creation time. */ 147 __u8 nsize; /* Name length. */ 148 __u8 nlink; /* Number of links. */ 149 __u8 deleted; /* Has this file been deleted? */ 150 char *name; /* The name of this file; NULL-terminated. */ 151 __u32 size; /* The total size of the file's data. */ 152 __u32 highest_version; /* The highest version number of this file. */ 153 struct jffs_control *c; 154 struct jffs_file *parent; /* Reference to the parent directory. */ 155 struct jffs_file *children; /* Always NULL for plain files. */ 156 struct jffs_file *sibling_prev; /* Siblings in the same directory. */ 157 struct jffs_file *sibling_next; 158 struct list_head hash; /* hash list. */ 159 struct jffs_node *range_head; /* The final data. */ 160 struct jffs_node *range_tail; /* The first data. */ 161 struct jffs_node *version_head; /* The youngest node. */ 162 struct jffs_node *version_tail; /* The oldest node. */ 163 }; 164 165 166 /* This is just a definition of a simple list used for keeping track of 167 files deleted due to a rename. This list is only used during the 168 mounting of the file system and only if there have been rename operations 169 earlier. */ 170 struct jffs_delete_list 171 { 172 __u32 ino; 173 struct jffs_delete_list *next; 174 }; 175 176 177 /* A struct for the overall file system control. Pointers to 178 jffs_control structs are named `c' in the source code. */ 179 struct jffs_control 180 { 181 struct super_block *sb; /* Reference to the VFS super block. */ 182 struct jffs_file *root; /* The root directory file. */ 183 struct list_head *hash; /* Hash table for finding files by ino. */ 184 struct jffs_fmcontrol *fmc; /* Flash memory control structure. */ 185 __u32 hash_len; /* The size of the hash table. */ 186 __u32 next_ino; /* Next inode number to use for new files. */ 187 __u16 building_fs; /* Is the file system being built right now? */ 188 struct jffs_delete_list *delete_list; /* Track deleted files. */ 189 pid_t thread_pid; /* GC thread's PID */ 190 struct task_struct *gc_task; /* GC task struct */ 191 struct completion gc_thread_comp; /* GC thread exit mutex */ 192 __u32 gc_minfree_threshold; /* GC trigger thresholds */ 193 __u32 gc_maxdirty_threshold; 194 }; 195 196 197 /* Used to inform about flash status. */ 198 struct jffs_flash_status 199 { 200 __u32 size; 201 __u32 used; 202 __u32 dirty; 203 __u32 begin; 204 __u32 end; 205 }; 206 207 /* This stuff could be used for finding memory leaks. */ 208 #define JFFS_MEMORY_DEBUG 0 209 210 extern long no_jffs_node; 211 extern long no_jffs_file; 212 #if defined(JFFS_MEMORY_DEBUG) && JFFS_MEMORY_DEBUG 213 extern long no_jffs_control; 214 extern long no_jffs_raw_inode; 215 extern long no_jffs_node_ref; 216 extern long no_jffs_fm; 217 extern long no_jffs_fmcontrol; 218 extern long no_hash; 219 extern long no_name; 220 #define DJM(x) x 221 #else 222 #define DJM(x) 223 #endif 224 225 #endif /* __LINUX_JFFS_H__ */ 226