yaffs_guts.h

yaffs2 lastest sourcecode~~

/*
 * YAFFS: Yet another Flash File System . A NAND-flash specific file system.
 *
 * Copyright (C) 2002-2007 Aleph One Ltd.
 *   for Toby Churchill Ltd and Brightstar Engineering
 *
 * Created by Charles Manning <[e-mail]>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License version 2.1 as
 * published by the Free Software Foundation.
 *
 * Note: Only YAFFS headers are LGPL, YAFFS C code is covered by GPL.
 */

#ifndef __YAFFS_GUTS_H__
#define __YAFFS_GUTS_H__

#include "devextras.h"
#include "yportenv.h"

#define YAFFS_OK	1
#define YAFFS_FAIL  0

/* Give us a  Y=0x59,
 * Give us an A=0x41,
 * Give us an FF=0xFF
 * Give us an S=0x53
 * And what have we got...
 */
#define YAFFS_MAGIC			0x5941FF53

#define YAFFS_NTNODES_LEVEL0	  	16
#define YAFFS_TNODES_LEVEL0_BITS	4
#define YAFFS_TNODES_LEVEL0_MASK	0xf

#define YAFFS_NTNODES_INTERNAL 		(YAFFS_NTNODES_LEVEL0 / 2)
#define YAFFS_TNODES_INTERNAL_BITS 	(YAFFS_TNODES_LEVEL0_BITS - 1)
#define YAFFS_TNODES_INTERNAL_MASK	0x7
#define YAFFS_TNODES_MAX_LEVEL		6

#ifndef CONFIG_YAFFS_NO_YAFFS1
#define YAFFS_BYTES_PER_SPARE		16
#define YAFFS_BYTES_PER_CHUNK		512
#define YAFFS_CHUNK_SIZE_SHIFT		9
#define YAFFS_CHUNKS_PER_BLOCK		32
#define YAFFS_BYTES_PER_BLOCK		(YAFFS_CHUNKS_PER_BLOCK*YAFFS_BYTES_PER_CHUNK)
#endif

#define YAFFS_MIN_YAFFS2_CHUNK_SIZE 	1024
#define YAFFS_MIN_YAFFS2_SPARE_SIZE	32

#define YAFFS_MAX_CHUNK_ID		0x000FFFFF

#define YAFFS_UNUSED_OBJECT_ID		0x0003FFFF

#define YAFFS_ALLOCATION_NOBJECTS	100
#define YAFFS_ALLOCATION_NTNODES	100
#define YAFFS_ALLOCATION_NLINKS		100

#define YAFFS_NOBJECT_BUCKETS		256


#define YAFFS_OBJECT_SPACE		0x40000

#define YAFFS_CHECKPOINT_VERSION 	3

#ifdef CONFIG_YAFFS_UNICODE
#define YAFFS_MAX_NAME_LENGTH		127
#define YAFFS_MAX_ALIAS_LENGTH		79
#else
#define YAFFS_MAX_NAME_LENGTH		255
#define YAFFS_MAX_ALIAS_LENGTH		159
#endif

#define YAFFS_SHORT_NAME_LENGTH		15

/* Some special object ids for pseudo objects */
#define YAFFS_OBJECTID_ROOT		1
#define YAFFS_OBJECTID_LOSTNFOUND	2
#define YAFFS_OBJECTID_UNLINKED		3
#define YAFFS_OBJECTID_DELETED		4

/* Sseudo object ids for checkpointing */
#define YAFFS_OBJECTID_SB_HEADER	0x10
#define YAFFS_OBJECTID_CHECKPOINT_DATA	0x20
#define YAFFS_SEQUENCE_CHECKPOINT_DATA  0x21

/* */

#define YAFFS_MAX_SHORT_OP_CACHES	20

#define YAFFS_N_TEMP_BUFFERS		6

/* We limit the number attempts at sucessfully saving a chunk of data.
 * Small-page devices have 32 pages per block; large-page devices have 64.
 * Default to something in the order of 5 to 10 blocks worth of chunks.
 */
#define YAFFS_WR_ATTEMPTS		(5*64)

/* Sequence numbers are used in YAFFS2 to determine block allocation order.
 * The range is limited slightly to help distinguish bad numbers from good.
 * This also allows us to perhaps in the future use special numbers for
 * special purposes.
 * EFFFFF00 allows the allocation of 8 blocks per second (~1Mbytes) for 15 years,
 * and is a larger number than the lifetime of a 2GB device.
 */
#define YAFFS_LOWEST_SEQUENCE_NUMBER	0x00001000
#define YAFFS_HIGHEST_SEQUENCE_NUMBER	0xEFFFFF00

/* Special sequence number for bad block that failed to be marked bad */
#define YAFFS_SEQUENCE_BAD_BLOCK	0xFFFF0000

/* ChunkCache is used for short read/write operations.*/
typedef struct {
	struct yaffs_ObjectStruct *object;
	int chunkId;
	int lastUse;
	int dirty;
	int nBytes;		/* Only valid if the cache is dirty */
	int locked;		/* Can't push out or flush while locked. */
#ifdef CONFIG_YAFFS_YAFFS2
	__u8 *data;
#else
	__u8 data[YAFFS_BYTES_PER_CHUNK];
#endif
} yaffs_ChunkCache;



/* Tags structures in RAM
 * NB This uses bitfield. Bitfields should not straddle a u32 boundary otherwise
 * the structure size will get blown out.
 */

#ifndef CONFIG_YAFFS_NO_YAFFS1
typedef struct {
	unsigned chunkId:20;
	unsigned serialNumber:2;
	unsigned byteCountLSB:10;
	unsigned objectId:18;
	unsigned ecc:12;
	unsigned byteCountMSB:2;
} yaffs_Tags;

typedef union {
	yaffs_Tags asTags;
	__u8 asBytes[8];
} yaffs_TagsUnion;

#endif

/* Stuff used for extended tags in YAFFS2 */

typedef enum {
	YAFFS_ECC_RESULT_UNKNOWN,
	YAFFS_ECC_RESULT_NO_ERROR,
	YAFFS_ECC_RESULT_FIXED,
	YAFFS_ECC_RESULT_UNFIXED
} yaffs_ECCResult;

typedef enum {
	YAFFS_OBJECT_TYPE_UNKNOWN,
	YAFFS_OBJECT_TYPE_FILE,
	YAFFS_OBJECT_TYPE_SYMLINK,
	YAFFS_OBJECT_TYPE_DIRECTORY,
	YAFFS_OBJECT_TYPE_HARDLINK,
	YAFFS_OBJECT_TYPE_SPECIAL
} yaffs_ObjectType;

#define YAFFS_OBJECT_TYPE_MAX YAFFS_OBJECT_TYPE_SPECIAL

typedef struct {

	unsigned validMarker0;
	unsigned chunkUsed;	/*  Status of the chunk: used or unused */
	unsigned objectId;	/* If 0 then this is not part of an object (unused) */
	unsigned chunkId;	/* If 0 then this is a header, else a data chunk */
	unsigned byteCount;	/* Only valid for data chunks */

	/* The following stuff only has meaning when we read */
	yaffs_ECCResult eccResult;
	unsigned blockBad;

	/* YAFFS 1 stuff */
	unsigned chunkDeleted;	/* The chunk is marked deleted */
	unsigned serialNumber;	/* Yaffs1 2-bit serial number */

	/* YAFFS2 stuff */
	unsigned sequenceNumber;	/* The sequence number of this block */

	/* Extra info if this is an object header (YAFFS2 only) */

	unsigned extraHeaderInfoAvailable;	/* There is extra info available if this is not zero */
	unsigned extraParentObjectId;	/* The parent object */
	unsigned extraIsShrinkHeader;	/* Is it a shrink header? */
	unsigned extraShadows;		/* Does this shadow another object? */

	yaffs_ObjectType extraObjectType;	/* What object type? */

	unsigned extraFileLength;		/* Length if it is a file */
	unsigned extraEquivalentObjectId;	/* Equivalent object Id if it is a hard link */

	unsigned validMarker1;

} yaffs_ExtendedTags;

/* Spare structure for YAFFS1 */
typedef struct {
	__u8 tagByte0;
	__u8 tagByte1;
	__u8 tagByte2;
	__u8 tagByte3;
	__u8 pageStatus;	/* set to 0 to delete the chunk */
	__u8 blockStatus;
	__u8 tagByte4;
	__u8 tagByte5;
	__u8 ecc1[3];
	__u8 tagByte6;
	__u8 tagByte7;
	__u8 ecc2[3];
} yaffs_Spare;

/*Special structure for passing through to mtd */
struct yaffs_NANDSpare {
	yaffs_Spare spare;
	int eccres1;
	int eccres2;
};

/* Block data in RAM */

typedef enum {
	YAFFS_BLOCK_STATE_UNKNOWN = 0,

	YAFFS_BLOCK_STATE_SCANNING,
	YAFFS_BLOCK_STATE_NEEDS_SCANNING,
	/* The block might have something on it (ie it is allocating or full, perhaps empty)
	 * but it needs to be scanned to determine its true state.
	 * This state is only valid during yaffs_Scan.
	 * NB We tolerate empty because the pre-scanner might be incapable of deciding
	 * However, if this state is returned on a YAFFS2 device, then we expect a sequence number
	 */

	YAFFS_BLOCK_STATE_EMPTY,
	/* This block is empty */

	YAFFS_BLOCK_STATE_ALLOCATING,
	/* This block is partially allocated.
	 * At least one page holds valid data.
	 * This is the one currently being used for page
	 * allocation. Should never be more than one of these
	 */

	YAFFS_BLOCK_STATE_FULL,
	/* All the pages in this block have been allocated.
	 */

	YAFFS_BLOCK_STATE_DIRTY,
	/* All pages have been allocated and deleted.
	 * Erase me, reuse me.
	 */

	YAFFS_BLOCK_STATE_CHECKPOINT,
	/* This block is assigned to holding checkpoint data.
	 */

	YAFFS_BLOCK_STATE_COLLECTING,
	/* This block is being garbage collected */

	YAFFS_BLOCK_STATE_DEAD
	/* This block has failed and is not in use */
} yaffs_BlockState;

#define	YAFFS_NUMBER_OF_BLOCK_STATES (YAFFS_BLOCK_STATE_DEAD + 1)


typedef struct {

	int softDeletions:10;	/* number of soft deleted pages */
	int pagesInUse:10;	/* number of pages in use */
	unsigned blockState:4;	/* One of the above block states. NB use unsigned because enum is sometimes an int */
	__u32 needsRetiring:1;	/* Data has failed on this block, need to get valid data off */
				/* and retire the block. */
	__u32 skipErasedCheck:1; /* If this is set we can skip the erased check on this block */
	__u32 gcPrioritise:1; 	/* An ECC check or blank check has failed on this block.
				   It should be prioritised for GC */
	__u32 chunkErrorStrikes:3; /* How many times we've had ecc etc failures on this block and tried to reuse it */

#ifdef CONFIG_YAFFS_YAFFS2
	__u32 hasShrinkHeader:1; /* This block has at least one shrink object header */
	__u32 sequenceNumber;	 /* block sequence number for yaffs2 */
#endif

} yaffs_BlockInfo;

/* -------------------------- Object structure -------------------------------*/
/* This is the object structure as stored on NAND */

typedef struct {
	yaffs_ObjectType type;

	/* Apply to everything  */
	int parentObjectId;
	__u16 sum__NoLongerUsed;        /* checksum of name. No longer used */
	YCHAR name[YAFFS_MAX_NAME_LENGTH + 1];

	/* The following apply to directories, files, symlinks - not hard links */
	__u32 yst_mode;         /* protection */

#ifdef CONFIG_YAFFS_WINCE
	__u32 notForWinCE[5];
#else
	__u32 yst_uid;
	__u32 yst_gid;
	__u32 yst_atime;
	__u32 yst_mtime;
	__u32 yst_ctime;
#endif

	/* File size  applies to files only */
	int fileSize;

	/* Equivalent object id applies to hard links only. */
	int equivalentObjectId;

	/* Alias is for symlinks only. */
	YCHAR alias[YAFFS_MAX_ALIAS_LENGTH + 1];

	__u32 yst_rdev;		/* device stuff for block and char devices (major/min) */

#ifdef CONFIG_YAFFS_WINCE
	__u32 win_ctime[2];
	__u32 win_atime[2];
	__u32 win_mtime[2];
#else
	__u32 roomToGrow[6];

#endif
	__u32 inbandShadowsObject;
	__u32 inbandIsShrink;

	__u32 reservedSpace[2];
	int shadowsObject;	/* This object header shadows the specified object if > 0 */

	/* isShrink applies to object headers written when we shrink the file (ie resize) */
	__u32 isShrink;

} yaffs_ObjectHeader;

/*--------------------------- Tnode -------------------------- */

union yaffs_Tnode_union {
#ifdef CONFIG_YAFFS_TNODE_LIST_DEBUG
	union yaffs_Tnode_union *internal[YAFFS_NTNODES_INTERNAL + 1];
#else
	union yaffs_Tnode_union *internal[YAFFS_NTNODES_INTERNAL];
#endif
/*	__u16 level0[YAFFS_NTNODES_LEVEL0]; */

};

typedef union yaffs_Tnode_union yaffs_Tnode;

struct yaffs_TnodeList_struct {
	struct yaffs_TnodeList_struct *next;
	yaffs_Tnode *tnodes;
};

typedef struct yaffs_TnodeList_struct yaffs_TnodeList;

/*------------------------  Object -----------------------------*/
/* An object can be one of:
 * - a directory (no data, has children links
 * - a regular file (data.... not prunes :->).
 * - a symlink [symbolic link] (the alias).
 * - a hard link
 */

typedef struct {
	__u32 fileSize;
	__u32 scannedFileSize;
	__u32 shrinkSize;
	int topLevel;
	yaffs_Tnode *top;
} yaffs_FileStructure;

typedef struct {
	struct ylist_head children;     /* list of child links */
} yaffs_DirectoryStructure;

typedef struct {
	YCHAR *alias;
} yaffs_SymLinkStructure;

typedef struct {
	struct yaffs_ObjectStruct *equivalentObject;
	__u32 equivalentObjectId;
} yaffs_HardLinkStructure;

typedef union {
	yaffs_FileStructure fileVariant;
	yaffs_DirectoryStructure directoryVariant;
	yaffs_SymLinkStructure symLinkVariant;
	yaffs_HardLinkStructure hardLinkVariant;
} yaffs_ObjectVariant;

struct yaffs_ObjectStruct {
	__u8 deleted:1;		/* This should only apply to unlinked files. */
	__u8 softDeleted:1;	/* it has also been soft deleted */
	__u8 unlinked:1;	/* An unlinked file. The file should be in the unlinked directory.*/
	__u8 fake:1;		/* A fake object has no presence on NAND. */
	__u8 renameAllowed:1;	/* Some objects are not allowed to be renamed. */
	__u8 unlinkAllowed:1;
	__u8 dirty:1;		/* the object needs to be written to flash */
	__u8 valid:1;		/* When the file system is being loaded up, this
				 * object might be created before the data
				 * is available (ie. file data records appear before the header).
				 */
	__u8 lazyLoaded:1;	/* This object has been lazy loaded and is missing some detail */

	__u8 deferedFree:1;	/* For Linux kernel. Object is removed from NAND, but is
				 * still in the inode cache. Free of object is defered.
				 * until the inode is released.
				 */
	__u8 beingCreated:1;	/* This object is still being created so skip some checks. */

	__u8 serial;		/* serial number of chunk in NAND. Cached here */
	__u16 sum;		/* sum of the name to speed searching */

	struct yaffs_DeviceStruct *myDev;       /* The device I'm on */

	struct ylist_head hashLink;     /* list of objects in this hash bucket */

	struct ylist_head hardLinks;    /* all the equivalent hard linked objects */

	/* directory structure stuff */
	/* also used for linking up the free list */
	struct yaffs_ObjectStruct *parent;
	struct ylist_head siblings;

	/* Where's my object header in NAND? */
	int hdrChunk;

	int nDataChunks;	/* Number of data chunks attached to the file. */

	__u32 objectId;		/* the object id value */

	__u32 yst_mode;

#ifdef CONFIG_YAFFS_SHORT_NAMES_IN_RAM
	YCHAR shortName[YAFFS_SHORT_NAME_LENGTH + 1];
#endif