225 lines
8.1 KiB
C
225 lines
8.1 KiB
C
/*
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* JFFS -- Journalling Flash File System, Linux implementation.
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*
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* Copyright (C) 1999, 2000 Axis Communications AB.
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*
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* Created by Finn Hakansson <finn@axis.com>.
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*
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* This is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* $Id: jffs.h,v 1.20 2001/09/18 21:33:37 dwmw2 Exp $
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*
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* Ported to Linux 2.3.x and MTD:
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* Copyright (C) 2000 Alexander Larsson (alex@cendio.se), Cendio Systems AB
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*
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*/
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#ifndef __LINUX_JFFS_H__
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#define __LINUX_JFFS_H__
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#include <linux/types.h>
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#include <linux/completion.h>
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#define JFFS_VERSION_STRING "1.0"
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/* This is a magic number that is used as an identification number for
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this file system. It is written to the super_block structure. */
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#define JFFS_MAGIC_SB_BITMASK 0x07c0 /* 1984 */
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/* This is a magic number that every on-flash raw inode begins with. */
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#define JFFS_MAGIC_BITMASK 0x34383931 /* "1984" */
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/* These two bitmasks are the valid ones for the flash memories we have
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for the moment. */
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#define JFFS_EMPTY_BITMASK 0xffffffff
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#define JFFS_DIRTY_BITMASK 0x00000000
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/* This is the inode number of the root node. */
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#define JFFS_MIN_INO 1
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/* How many slots in the file hash table should we have? */
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#define JFFS_HASH_SIZE 40
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/* Don't use more than 254 bytes as the maximum allowed length of a file's
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name due to errors that could occur during the scanning of the flash
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memory. In fact, a name length of 255 or 0xff, could be the result of
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an uncompleted write. For instance, if a raw inode is written to the
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flash memory and there is a power lossage just before the length of
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the name is written, the length 255 would be interpreted as an illegal
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value. */
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#define JFFS_MAX_NAME_LEN 254
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/* Commands for ioctl(). */
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#define JFFS_IOCTL_MAGIC 't'
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#define JFFS_PRINT_HASH _IO(JFFS_IOCTL_MAGIC, 90)
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#define JFFS_PRINT_TREE _IO(JFFS_IOCTL_MAGIC, 91)
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#define JFFS_GET_STATUS _IO(JFFS_IOCTL_MAGIC, 92)
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/* XXX: This is something that we should try to get rid of in the future. */
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#define JFFS_MODIFY_INODE 0x01
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#define JFFS_MODIFY_NAME 0x02
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#define JFFS_MODIFY_DATA 0x04
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#define JFFS_MODIFY_EXIST 0x08
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struct jffs_control;
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/* The JFFS raw inode structure: Used for storage on physical media. */
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/* Perhaps the uid, gid, atime, mtime and ctime members should have
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more space due to future changes in the Linux kernel. Anyhow, since
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a user of this filesystem probably have to fix a large number of
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other things, we have decided to not be forward compatible. */
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struct jffs_raw_inode
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{
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__u32 magic; /* A constant magic number. */
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__u32 ino; /* Inode number. */
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__u32 pino; /* Parent's inode number. */
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__u32 version; /* Version number. */
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__u32 mode; /* The file's type or mode. */
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__u16 uid; /* The file's owner. */
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__u16 gid; /* The file's group. */
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__u32 atime; /* Last access time. */
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__u32 mtime; /* Last modification time. */
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__u32 ctime; /* Creation time. */
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__u32 offset; /* Where to begin to write. */
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__u32 dsize; /* Size of the node's data. */
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__u32 rsize; /* How much are going to be replaced? */
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__u8 nsize; /* Name length. */
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__u8 nlink; /* Number of links. */
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__u8 spare : 6; /* For future use. */
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__u8 rename : 1; /* Rename to a name of an already existing file? */
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__u8 deleted : 1; /* Has this file been deleted? */
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__u8 accurate; /* The inode is obsolete if accurate == 0. */
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__u32 dchksum; /* Checksum for the data. */
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__u16 nchksum; /* Checksum for the name. */
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__u16 chksum; /* Checksum for the raw inode. */
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};
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/* Define the offset of the accurate byte in struct jffs_raw_inode. */
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#define JFFS_RAW_INODE_ACCURATE_OFFSET (sizeof(struct jffs_raw_inode) \
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- 2 * sizeof(__u32) - sizeof(__u8))
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/* Define the offset of the chksum member in struct jffs_raw_inode. */
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#define JFFS_RAW_INODE_CHKSUM_OFFSET (sizeof(struct jffs_raw_inode) \
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- sizeof(__u16))
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/* Define the offset of the dchksum member in struct jffs_raw_inode. */
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#define JFFS_RAW_INODE_DCHKSUM_OFFSET (sizeof(struct jffs_raw_inode) \
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- sizeof(__u16) - sizeof(__u16) \
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- sizeof(__u32))
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/* The RAM representation of the node. The names of pointers to
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jffs_nodes are very often just called `n' in the source code. */
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struct jffs_node
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{
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__u32 ino; /* Inode number. */
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__u32 version; /* Version number. */
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__u32 data_offset; /* Logic location of the data to insert. */
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__u32 data_size; /* The amount of data this node inserts. */
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__u32 removed_size; /* The amount of data that this node removes. */
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__u32 fm_offset; /* Physical location of the data in the actual
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flash memory data chunk. */
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__u8 name_size; /* Size of the name. */
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struct jffs_fm *fm; /* Physical memory information. */
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struct jffs_node *version_prev;
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struct jffs_node *version_next;
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struct jffs_node *range_prev;
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struct jffs_node *range_next;
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};
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/* The RAM representation of a file (plain files, directories,
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links, etc.). Pointers to jffs_files are normally named `f'
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in the JFFS source code. */
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struct jffs_file
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{
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__u32 ino; /* Inode number. */
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__u32 pino; /* Parent's inode number. */
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__u32 mode; /* file_type, mode */
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__u16 uid; /* owner */
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__u16 gid; /* group */
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__u32 atime; /* Last access time. */
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__u32 mtime; /* Last modification time. */
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__u32 ctime; /* Creation time. */
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__u8 nsize; /* Name length. */
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__u8 nlink; /* Number of links. */
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__u8 deleted; /* Has this file been deleted? */
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char *name; /* The name of this file; NULL-terminated. */
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__u32 size; /* The total size of the file's data. */
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__u32 highest_version; /* The highest version number of this file. */
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struct jffs_control *c;
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struct jffs_file *parent; /* Reference to the parent directory. */
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struct jffs_file *children; /* Always NULL for plain files. */
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struct jffs_file *sibling_prev; /* Siblings in the same directory. */
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struct jffs_file *sibling_next;
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struct list_head hash; /* hash list. */
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struct jffs_node *range_head; /* The final data. */
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struct jffs_node *range_tail; /* The first data. */
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struct jffs_node *version_head; /* The youngest node. */
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struct jffs_node *version_tail; /* The oldest node. */
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};
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/* This is just a definition of a simple list used for keeping track of
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files deleted due to a rename. This list is only used during the
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mounting of the file system and only if there have been rename operations
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earlier. */
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struct jffs_delete_list
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{
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__u32 ino;
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struct jffs_delete_list *next;
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};
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/* A struct for the overall file system control. Pointers to
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jffs_control structs are named `c' in the source code. */
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struct jffs_control
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{
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struct super_block *sb; /* Reference to the VFS super block. */
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struct jffs_file *root; /* The root directory file. */
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struct list_head *hash; /* Hash table for finding files by ino. */
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struct jffs_fmcontrol *fmc; /* Flash memory control structure. */
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__u32 hash_len; /* The size of the hash table. */
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__u32 next_ino; /* Next inode number to use for new files. */
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__u16 building_fs; /* Is the file system being built right now? */
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struct jffs_delete_list *delete_list; /* Track deleted files. */
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pid_t thread_pid; /* GC thread's PID */
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struct task_struct *gc_task; /* GC task struct */
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struct completion gc_thread_comp; /* GC thread exit mutex */
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__u32 gc_minfree_threshold; /* GC trigger thresholds */
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__u32 gc_maxdirty_threshold;
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};
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/* Used to inform about flash status. */
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struct jffs_flash_status
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{
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__u32 size;
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__u32 used;
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__u32 dirty;
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__u32 begin;
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__u32 end;
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};
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/* This stuff could be used for finding memory leaks. */
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#define JFFS_MEMORY_DEBUG 0
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extern long no_jffs_node;
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#if defined(JFFS_MEMORY_DEBUG) && JFFS_MEMORY_DEBUG
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extern long no_jffs_control;
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extern long no_jffs_raw_inode;
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extern long no_jffs_node_ref;
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extern long no_jffs_fm;
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extern long no_jffs_fmcontrol;
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extern long no_hash;
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extern long no_name;
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#define DJM(x) x
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#else
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#define DJM(x)
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#endif
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#endif /* __LINUX_JFFS_H__ */
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