nodelist.h

来自「开放源码实时操作系统源码.」· C头文件 代码 · 共 395 行 · 第 1/2 页

/*
 * JFFS2 -- Journalling Flash File System, Version 2.
 *
 * Copyright (C) 2001-2003 Red Hat, Inc.
 *
 * Created by David Woodhouse <[e-mail]>
 *
 * For licensing information, see the file 'LICENCE' in this directory.
 *
 * $Id: nodelist.h,v 1.135 2005/07/27 14:46:11 dedekind Exp $
 *
 */

#ifndef __JFFS2_NODELIST_H__
#define __JFFS2_NODELIST_H__

#include <linux/config.h>
#include <linux/fs.h>
#include <linux/types.h>
#include <linux/jffs2.h>
#include <linux/jffs2_fs_sb.h>
#include <linux/jffs2_fs_i.h>

#ifdef __ECOS
#include "os-ecos.h"
#else
#include <linux/mtd/compatmac.h> /* For compatibility with older kernels */
#include "os-linux.h"
#endif

#define JFFS2_NATIVE_ENDIAN

/* Note we handle mode bits conversion from JFFS2 (i.e. Linux) to/from
   whatever OS we're actually running on here too. */

#if defined(JFFS2_NATIVE_ENDIAN)
#define cpu_to_je16(x) ((jint16_t){x})
#define cpu_to_je32(x) ((jint32_t){x})
#define cpu_to_jemode(x) ((jmode_t){os_to_jffs2_mode(x)})

#define je16_to_cpu(x) ((x).v16)
#define je32_to_cpu(x) ((x).v32)
#define jemode_to_cpu(x) (jffs2_to_os_mode((x).m))
#elif defined(JFFS2_BIG_ENDIAN)
#define cpu_to_je16(x) ((jint16_t){cpu_to_be16(x)})
#define cpu_to_je32(x) ((jint32_t){cpu_to_be32(x)})
#define cpu_to_jemode(x) ((jmode_t){cpu_to_be32(os_to_jffs2_mode(x))})

#define je16_to_cpu(x) (be16_to_cpu(x.v16))
#define je32_to_cpu(x) (be32_to_cpu(x.v32))
#define jemode_to_cpu(x) (be32_to_cpu(jffs2_to_os_mode((x).m)))
#elif defined(JFFS2_LITTLE_ENDIAN)
#define cpu_to_je16(x) ((jint16_t){cpu_to_le16(x)})
#define cpu_to_je32(x) ((jint32_t){cpu_to_le32(x)})
#define cpu_to_jemode(x) ((jmode_t){cpu_to_le32(os_to_jffs2_mode(x))})

#define je16_to_cpu(x) (le16_to_cpu(x.v16))
#define je32_to_cpu(x) (le32_to_cpu(x.v32))
#define jemode_to_cpu(x) (le32_to_cpu(jffs2_to_os_mode((x).m)))
#else 
#error wibble
#endif

/*
  This is all we need to keep in-core for each raw node during normal
  operation. As and when we do read_inode on a particular inode, we can
  scan the nodes which are listed for it and build up a proper map of 
  which nodes are currently valid. JFFSv1 always used to keep that whole
  map in core for each inode.
*/
struct jffs2_raw_node_ref
{
	struct jffs2_raw_node_ref *next_in_ino; /* Points to the next raw_node_ref
		for this inode. If this is the last, it points to the inode_cache
		for this inode instead. The inode_cache will have NULL in the first
		word so you know when you've got there :) */
	struct jffs2_raw_node_ref *next_phys;
	uint32_t flash_offset;
	uint32_t __totlen; /* This may die; use ref_totlen(c, jeb, ) below */
};

        /* flash_offset & 3 always has to be zero, because nodes are
	   always aligned at 4 bytes. So we have a couple of extra bits
	   to play with, which indicate the node's status; see below: */ 
#define REF_UNCHECKED	0	/* We haven't yet checked the CRC or built its inode */
#define REF_OBSOLETE	1	/* Obsolete, can be completely ignored */
#define REF_PRISTINE	2	/* Completely clean. GC without looking */
#define REF_NORMAL	3	/* Possibly overlapped. Read the page and write again on GC */
#define ref_flags(ref)		((ref)->flash_offset & 3)
#define ref_offset(ref)		((ref)->flash_offset & ~3)
#define ref_obsolete(ref)	(((ref)->flash_offset & 3) == REF_OBSOLETE)
#define mark_ref_normal(ref)    do { (ref)->flash_offset = ref_offset(ref) | REF_NORMAL; } while(0)

/* For each inode in the filesystem, we need to keep a record of
   nlink, because it would be a PITA to scan the whole directory tree
   at read_inode() time to calculate it, and to keep sufficient information
   in the raw_node_ref (basically both parent and child inode number for 
   dirent nodes) would take more space than this does. We also keep
   a pointer to the first physical node which is part of this inode, too.
*/
struct jffs2_inode_cache {
	struct jffs2_full_dirent *scan_dents; /* Used during scan to hold
		temporary lists of dirents, and later must be set to
		NULL to mark the end of the raw_node_ref->next_in_ino
		chain. */
	struct jffs2_inode_cache *next;
	struct jffs2_raw_node_ref *nodes;
	uint32_t ino;
	int nlink;
	int state;
};

/* Inode states for 'state' above. We need the 'GC' state to prevent
   someone from doing a read_inode() while we're moving a 'REF_PRISTINE'
   node without going through all the iget() nonsense */
#define INO_STATE_UNCHECKED	0	/* CRC checks not yet done */
#define INO_STATE_CHECKING	1	/* CRC checks in progress */
#define INO_STATE_PRESENT	2	/* In core */
#define INO_STATE_CHECKEDABSENT	3	/* Checked, cleared again */
#define INO_STATE_GC		4	/* GCing a 'pristine' node */
#define INO_STATE_READING	5	/* In read_inode() */
#define INO_STATE_CLEARING	6	/* In clear_inode() */

#define INOCACHE_HASHSIZE 128

/*
  Larger representation of a raw node, kept in-core only when the 
  struct inode for this particular ino is instantiated.
*/

struct jffs2_full_dnode
{
	struct jffs2_raw_node_ref *raw;
	uint32_t ofs; /* The offset to which the data of this node belongs */
	uint32_t size;
	uint32_t frags; /* Number of fragments which currently refer
			to this node. When this reaches zero, 
			the node is obsolete.  */
};

/* 
   Even larger representation of a raw node, kept in-core only while
   we're actually building up the original map of which nodes go where,
   in read_inode()
*/
struct jffs2_tmp_dnode_info
{
	struct rb_node rb;
	struct jffs2_full_dnode *fn;
	uint32_t version;
};       

struct jffs2_full_dirent
{
	struct jffs2_raw_node_ref *raw;
	struct jffs2_full_dirent *next;
	uint32_t version;
	uint32_t ino; /* == zero for unlink */
	unsigned int nhash;
	unsigned char type;
	unsigned char name[0];
};

/*
  Fragments - used to build a map of which raw node to obtain 
  data from for each part of the ino
*/
struct jffs2_node_frag
{
	struct rb_node rb;
	struct jffs2_full_dnode *node; /* NULL for holes */
	uint32_t size;
	uint32_t ofs; /* The offset to which this fragment belongs */
};

struct jffs2_eraseblock
{
	struct list_head list;
	int bad_count;
	uint32_t offset;		/* of this block in the MTD */

	uint32_t unchecked_size;
	uint32_t used_size;
	uint32_t dirty_size;
	uint32_t wasted_size;
	uint32_t free_size;	/* Note that sector_size - free_size
				   is the address of the first free space */
	struct jffs2_raw_node_ref *first_node;
	struct jffs2_raw_node_ref *last_node;

	struct jffs2_raw_node_ref *gc_node;	/* Next node to be garbage collected */
};

/* Calculate totlen from surrounding nodes or eraseblock */
static inline uint32_t __ref_totlen(struct jffs2_sb_info *c,
				    struct jffs2_eraseblock *jeb,
				    struct jffs2_raw_node_ref *ref)
{