include/linux/jffs.h

   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 #if defined(JFFS_MEMORY_DEBUG) && JFFS_MEMORY_DEBUG
 212 extern long no_jffs_control;
 213 extern long no_jffs_raw_inode;
 214 extern long no_jffs_node_ref;
 215 extern long no_jffs_fm;
 216 extern long no_jffs_fmcontrol;
 217 extern long no_hash;
 218 extern long no_name;
 219 #define DJM(x) x
 220 #else
 221 #define DJM(x)
 222 #endif
 223
 224 #endif /* __LINUX_JFFS_H__ */