yaffs_guts.c

yaffs２设备驱动

#else

		theObject->yst_atime = theObject->yst_mtime =
		    theObject->yst_ctime = Y_CURRENT_TIME;
#endif
		switch (type) {
		case YAFFS_OBJECT_TYPE_FILE:
			theObject->variant.fileVariant.fileSize = 0;
			theObject->variant.fileVariant.scannedFileSize = 0;
			theObject->variant.fileVariant.shrinkSize = 0xFFFFFFFF;	/* max __u32 */
			theObject->variant.fileVariant.topLevel = 0;
			theObject->variant.fileVariant.top =
			    yaffs_GetTnode(dev);
			break;
		case YAFFS_OBJECT_TYPE_DIRECTORY:
			INIT_LIST_HEAD(&theObject->variant.directoryVariant.
				       children);
			break;
		case YAFFS_OBJECT_TYPE_SYMLINK:
		case YAFFS_OBJECT_TYPE_HARDLINK:
		case YAFFS_OBJECT_TYPE_SPECIAL:
			/* No action required */
			break;
		case YAFFS_OBJECT_TYPE_UNKNOWN:
			/* todo this should not happen */
			break;
		}
	}

	return theObject;
}

static yaffs_Object *yaffs_FindOrCreateObjectByNumber(yaffs_Device * dev,
						      int number,
						      yaffs_ObjectType type)
{
	yaffs_Object *theObject = NULL;

	if (number > 0) {
		theObject = yaffs_FindObjectByNumber(dev, number);
	}

	if (!theObject) {
		theObject = yaffs_CreateNewObject(dev, number, type);
	}

	return theObject;

}
			

static YCHAR *yaffs_CloneString(const YCHAR * str)
{
	YCHAR *newStr = NULL;

	if (str && *str) {
		newStr = YMALLOC((yaffs_strlen(str) + 1) * sizeof(YCHAR));
		yaffs_strcpy(newStr, str);
	}

	return newStr;

}

/*
 * Mknod (create) a new object.
 * equivalentObject only has meaning for a hard link;
 * aliasString only has meaning for a sumlink.
 * rdev only has meaning for devices (a subset of special objects)
 */
 
static yaffs_Object *yaffs_MknodObject(yaffs_ObjectType type,
				       yaffs_Object * parent,
				       const YCHAR * name,
				       __u32 mode,
				       __u32 uid,
				       __u32 gid,
				       yaffs_Object * equivalentObject,
				       const YCHAR * aliasString, __u32 rdev)
{
	yaffs_Object *in;

	yaffs_Device *dev = parent->myDev;

	/* Check if the entry exists. If it does then fail the call since we don't want a dup.*/
	if (yaffs_FindObjectByName(parent, name)) {
		return NULL;
	}

	in = yaffs_CreateNewObject(dev, -1, type);

	if (in) {
		in->chunkId = -1;
		in->valid = 1;
		in->variantType = type;

		in->yst_mode = mode;

#ifdef CONFIG_YAFFS_WINCE
		yfsd_WinFileTimeNow(in->win_atime);
		in->win_ctime[0] = in->win_mtime[0] = in->win_atime[0];
		in->win_ctime[1] = in->win_mtime[1] = in->win_atime[1];

#else
		in->yst_atime = in->yst_mtime = in->yst_ctime = Y_CURRENT_TIME;

		in->yst_rdev = rdev;
		in->yst_uid = uid;
		in->yst_gid = gid;
#endif
		in->nDataChunks = 0;

		yaffs_SetObjectName(in, name);
		in->dirty = 1;

		yaffs_AddObjectToDirectory(parent, in);

		in->myDev = parent->myDev;

		switch (type) {
		case YAFFS_OBJECT_TYPE_SYMLINK:
			in->variant.symLinkVariant.alias =
			    yaffs_CloneString(aliasString);
			break;
		case YAFFS_OBJECT_TYPE_HARDLINK:
			in->variant.hardLinkVariant.equivalentObject =
			    equivalentObject;
			in->variant.hardLinkVariant.equivalentObjectId =
			    equivalentObject->objectId;
			list_add(&in->hardLinks, &equivalentObject->hardLinks);
			break;
		case YAFFS_OBJECT_TYPE_FILE:	
		case YAFFS_OBJECT_TYPE_DIRECTORY:
		case YAFFS_OBJECT_TYPE_SPECIAL:
		case YAFFS_OBJECT_TYPE_UNKNOWN:
			/* do nothing */
			break;
		}

		if (yaffs_UpdateObjectHeader(in, name, 0, 0, 0) < 0) {
			/* Could not create the object header, fail the creation */
			yaffs_DestroyObject(in);
			in = NULL;
		}

	}

	return in;
}

yaffs_Object *yaffs_MknodFile(yaffs_Object * parent, const YCHAR * name,
			      __u32 mode, __u32 uid, __u32 gid)
{
	return yaffs_MknodObject(YAFFS_OBJECT_TYPE_FILE, parent, name, mode,
				 uid, gid, NULL, NULL, 0);
}

yaffs_Object *yaffs_MknodDirectory(yaffs_Object * parent, const YCHAR * name,
				   __u32 mode, __u32 uid, __u32 gid)
{
	return yaffs_MknodObject(YAFFS_OBJECT_TYPE_DIRECTORY, parent, name,
				 mode, uid, gid, NULL, NULL, 0);
}

yaffs_Object *yaffs_MknodSpecial(yaffs_Object * parent, const YCHAR * name,
				 __u32 mode, __u32 uid, __u32 gid, __u32 rdev)
{
	return yaffs_MknodObject(YAFFS_OBJECT_TYPE_SPECIAL, parent, name, mode,
				 uid, gid, NULL, NULL, rdev);
}

yaffs_Object *yaffs_MknodSymLink(yaffs_Object * parent, const YCHAR * name,
				 __u32 mode, __u32 uid, __u32 gid,
				 const YCHAR * alias)
{
	return yaffs_MknodObject(YAFFS_OBJECT_TYPE_SYMLINK, parent, name, mode,
				 uid, gid, NULL, alias, 0);
}

/* yaffs_Link returns the object id of the equivalent object.*/
yaffs_Object *yaffs_Link(yaffs_Object * parent, const YCHAR * name,
			 yaffs_Object * equivalentObject)
{
	/* Get the real object in case we were fed a hard link as an equivalent object */
	equivalentObject = yaffs_GetEquivalentObject(equivalentObject);

	if (yaffs_MknodObject
	    (YAFFS_OBJECT_TYPE_HARDLINK, parent, name, 0, 0, 0,
	     equivalentObject, NULL, 0)) {
		return equivalentObject;
	} else {
		return NULL;
	}

}

static int yaffs_ChangeObjectName(yaffs_Object * obj, yaffs_Object * newDir,
				  const YCHAR * newName, int force, int shadows)
{
	int unlinkOp;
	int deleteOp;

	yaffs_Object *existingTarget;

	if (newDir == NULL) {
		newDir = obj->parent;	/* use the old directory */
	}

	if (newDir->variantType != YAFFS_OBJECT_TYPE_DIRECTORY) {
		T(YAFFS_TRACE_ALWAYS,
		  (TSTR
		   ("tragendy: yaffs_ChangeObjectName: newDir is not a directory"
		    TENDSTR)));
		YBUG();
	}
	
	/* TODO: Do we need this different handling for YAFFS2 and YAFFS1?? */
	if (obj->myDev->isYaffs2) {
		unlinkOp = (newDir == obj->myDev->unlinkedDir);
	} else {
		unlinkOp = (newDir == obj->myDev->unlinkedDir
			    && obj->variantType == YAFFS_OBJECT_TYPE_FILE);
	}

	deleteOp = (newDir == obj->myDev->deletedDir);

	existingTarget = yaffs_FindObjectByName(newDir, newName);

	/* If the object is a file going into the unlinked directory, 
	 *   then it is OK to just stuff it in since duplicate names are allowed.
	 *   else only proceed if the new name does not exist and if we're putting 
	 *   it into a directory.
	 */
	if ((unlinkOp ||
	     deleteOp ||
	     force ||
	     (shadows > 0) ||
	     !existingTarget) &&
	    newDir->variantType == YAFFS_OBJECT_TYPE_DIRECTORY) {
		yaffs_SetObjectName(obj, newName);
		obj->dirty = 1;

		yaffs_AddObjectToDirectory(newDir, obj);

		if (unlinkOp)
			obj->unlinked = 1;

		/* If it is a deletion then we mark it as a shrink for gc purposes. */
		if (yaffs_UpdateObjectHeader(obj, newName, 0, deleteOp, shadows)>= 0)
			return YAFFS_OK;
	}

	return YAFFS_FAIL;
}

int yaffs_RenameObject(yaffs_Object * oldDir, const YCHAR * oldName,
		       yaffs_Object * newDir, const YCHAR * newName)
{
	yaffs_Object *obj;
	yaffs_Object *existingTarget;
	int force = 0;

#ifdef CONFIG_YAFFS_CASE_INSENSITIVE
	/* Special case for case insemsitive systems (eg. WinCE).
	 * While look-up is case insensitive, the name isn't.
	 * Therefore we might want to change x.txt to X.txt
	*/
	if (oldDir == newDir && yaffs_strcmp(oldName, newName) == 0) {
		force = 1;
	}
#endif

	obj = yaffs_FindObjectByName(oldDir, oldName);
	/* Check new name to long. */
	if (obj->variantType == YAFFS_OBJECT_TYPE_SYMLINK &&
	    yaffs_strlen(newName) > YAFFS_MAX_ALIAS_LENGTH)
	  /* ENAMETOOLONG */
	  return YAFFS_FAIL;
	else if (obj->variantType != YAFFS_OBJECT_TYPE_SYMLINK &&
		 yaffs_strlen(newName) > YAFFS_MAX_NAME_LENGTH)
	  /* ENAMETOOLONG */
	  return YAFFS_FAIL;

	if (obj && obj->renameAllowed) {

		/* Now do the handling for an existing target, if there is one */

		existingTarget = yaffs_FindObjectByName(newDir, newName);
		if (existingTarget &&
		    existingTarget->variantType == YAFFS_OBJECT_TYPE_DIRECTORY &&
		    !list_empty(&existingTarget->variant.directoryVariant.children)) {
			/* There is a target that is a non-empty directory, so we fail */
			return YAFFS_FAIL;	/* EEXIST or ENOTEMPTY */
		} else if (existingTarget && existingTarget != obj) {
			/* Nuke the target first, using shadowing, 
			 * but only if it isn't the same object
			 */
			yaffs_ChangeObjectName(obj, newDir, newName, force,
					       existingTarget->objectId);
			yaffs_UnlinkObject(existingTarget);
		}

		return yaffs_ChangeObjectName(obj, newDir, newName, 1, 0);
	}
	return YAFFS_FAIL;
}

/*------------------------- Block Management and Page Allocation ----------------*/

static int yaffs_InitialiseBlocks(yaffs_Device * dev)
{
	int nBlocks = dev->internalEndBlock - dev->internalStartBlock + 1;
	
	dev->allocationBlock = -1;	/* force it to get a new one */

	/* Todo we're assuming the malloc will pass. */
	dev->blockInfo = YMALLOC(nBlocks * sizeof(yaffs_BlockInfo));
	if(!dev->blockInfo){
		dev->blockInfo = YMALLOC_ALT(nBlocks * sizeof(yaffs_BlockInfo));
		dev->blockInfoAlt = 1;
	}
	else
		dev->blockInfoAlt = 0;
	
	/* Set up dynamic blockinfo stuff. */
	dev->chunkBitmapStride = (dev->nChunksPerBlock + 7) / 8; /* round up bytes */
	dev->chunkBits = YMALLOC(dev->chunkBitmapStride * nBlocks);
	if(!dev->chunkBits){
		dev->chunkBits = YMALLOC_ALT(dev->chunkBitmapStride * nBlocks);
		dev->chunkBitsAlt = 1;
	}
	else
		dev->chunkBitsAlt = 0;
	
	if (dev->blockInfo && dev->chunkBits) {
		memset(dev->blockInfo, 0, nBlocks * sizeof(yaffs_BlockInfo));
		memset(dev->chunkBits, 0, dev->chunkBitmapStride * nBlocks);
		return YAFFS_OK;
	}

	return YAFFS_FAIL;

}

static void yaffs_DeinitialiseBlocks(yaffs_Device * dev)
{
	if(dev->blockInfoAlt)
		YFREE_ALT(dev->blockInfo);
	else
		YFREE(dev->blockInfo);
	dev->blockInfoAlt = 0;

	dev->blockInfo = NULL;
	
	if(dev->chunkBitsAlt)
		YFREE_ALT(dev->chunkBits);
	else
		YFREE(dev->chunkBits);
	dev->chunkBitsAlt = 0;
	dev->chunkBits = NULL;
}

static int yaffs_BlockNotDisqualifiedFromGC(yaffs_Device * dev,
					    yaffs_BlockInfo * bi)
{
	int i;
	__u32 seq;
	yaffs_BlockInfo *b;

	if (!dev->isYaffs2)
		return 1;	/* disqualification only applies to yaffs2. */

	if (!bi->hasShrinkHeader)
		return 1;	/* can gc */

	/* Find the oldest dirty sequence number if we don't know it and save it
	 * so we don't have to keep recomputing it.
	 */
	if (!dev->oldestDirtySequence) {
		seq = dev->sequenceNumber;

		for (i = dev->internalStartBlock; i <= dev->internalEndBlock;
		     i++) {
			b = yaffs_GetBlockInfo(dev, i);
			if (b->blockState == YAFFS_BLOCK_STATE_FULL &&
			    (b->pagesInUse - b->softDeletions) <
			    dev->nChunksPerBlock && b->sequenceNumber < seq) {
				seq = b->sequenceNumber;
			}
		}
		dev->oldestDirtySequence = seq;
	}

	/* Can't do gc of this block if there are any blocks older than this one that have
	 * discarded pages.
	 */
	return (bi->sequenceNumber <= dev->oldestDirtySequence);

}

/* FindDiretiestBlock is used to select the dirtiest block (or close enough)
 * for garbage collection.
 */

static int yaffs_FindBlockForGarbageCollection(yaffs_Device * dev,
					       int aggressive)
{

	int b = dev->currentDirtyChecker;

	int i;
	int iterations;
	int dirtiest = -1;
	int pagesInUse;
	int prioritised=0;
	yaffs_BlockInfo *bi;
	static int nonAggressiveSkip = 0;
	int pendingPrioritisedExist = 0;
	
	/* First let's see if we need to grab a prioritised block */
	if(dev->hasPendingPrioritisedGCs){
		for(i = dev->internalStartBlock; i < dev->internalEndBlock && !prioritised; i++){

			bi = yaffs_GetBlockInfo(dev, i);
			if(bi->gcPrioritise) {
				pendingPrioritisedExist = 1;
				if(bi->blockState == YAFFS_BLOCK_STATE_FULL &&
				   yaffs_BlockNotDisqualifiedFromGC(dev, bi)){
					pagesInUse = (bi->pagesInUse - bi->softDeletions);
					dirtiest = i;
					prioritised = 1;
					aggressive = 1; /* Fool the non-aggressive skip logiv below */
				}
			}
		}
		
		if(!pendingPrioritisedExist) /* None found, so we can clear this */
			dev->hasPendingPrioritisedGCs = 0;
	}

	/* If we're doing aggressive GC then we are happy to take a less-dirty block, and
	 * search harder.
	 * else (we're doing a leasurely gc), then we only bother to do this if the
	 * block has only a few pages in use.
	 */

	nonAggressiveSkip--;

	if (!aggressive && (nonAggressiveSkip > 0)) {
		return -1;
	}

	if(!prioritised)
		pagesInUse =
	    		(aggressive) ? dev->nChunksPerBlock : YAFFS_PASSIVE_GC_CHUNKS + 1;

	if (aggressive) {
		iterations =
		    dev->internalEndBlock - dev->internalStartBlock + 1;
	} else {
		iterations =
		    dev->internalEndBlock - dev->internalStartBlock + 1;
		iterations = iterations / 16;
		if (iterations > 200) {
			iterations = 200;
		}
	}

	for (i = 0; i <= iterations && pagesInUse > 0 && !prioritised; i++) {
		b++;
		if (b < dev->internalStartBlock || b > dev->internalEndBlock) {
			b = dev->internalStartBlock;
		}

		if (b < dev->internalStartBlock || b > dev->internalEndBlock) {
			T(YAFFS_TRACE_ERROR,
			  (TSTR("**>> Block %d is not valid" TENDSTR), b));
			YBUG();
		}

		bi = yaffs_GetBlockInfo(dev, b);

#if 0
		if (bi->blockState == YAFFS_BLOCK_STATE_CHECKPOINT) {
			dirtiest = b;
			pagesInUse = 0;
		}
		else 
#endif

		if (bi->blockState == YAFFS_BLOCK_STATE_FULL &&
		       (bi->pagesInUse - bi->softDeletions) < pagesInUse &&
		        yaffs_BlockNotDisqualifiedFromGC(dev, bi)) {
			dirtiest = b;
			pagesInUse = (bi->pagesInUse - bi->softDeletions);
		}
	}

	dev->currentDirtyChecker = b;

	if (dirtiest > 0) {
		T(YAFFS_TRACE_GC,
		  (TSTR("GC Selected block %d with %d free, prioritised:%d" TENDSTR), dirtiest,
		   dev->nChunksPerBlock - pagesInUse,prioritised));
	}

	dev->oldestDirtySequence = 0;

	if (dirtiest > 0) {
		nonAggressiveSkip = 4;
	}

	return dirtiest;
}

static void yaffs_BlockBecameDirty(yaffs_Device * dev, int blockNo)
{
	yaffs_BlockInfo *bi = yaffs_GetBlockInfo(dev, blockNo);

	int erasedOk = 0;

	/* If the block is still healthy erase it and mark as clean.
	 * If the block has had a data failure, then retire it.
	 */
	 
	T(YAFFS_TRACE_GC | YAFFS_TRACE_ERASE,
		(TSTR("yaffs_BlockBecameDirty block %d state %d %s"TENDSTR),
		blockNo, bi->blockState, (bi->needsRetiring) ? "needs retiring" : ""));
		
	bi->blockState = YAFFS_BLOCK_STATE_DIRTY;

	if (!bi->needsRetiring) {
		yaffs_InvalidateCheckpoint(dev);
		erasedOk = yaffs_EraseBlockInNAND(dev, blockNo);
		if (!erasedOk) {
			dev->nErasureFailures++;
			T(YAFFS_TRACE_ERROR | YAFFS_TRACE_BAD_BLOCKS,
			  (TSTR("**>> Erasure failed %d" TENDSTR), blockNo));
		}
	}

	if (erasedOk && (yaffs_traceMask & YAFFS_TRACE_ERASE)) {