yaffs_guts.c

yaffs2 source code for linux

}

yaffs_Object *yaffs_FindObjectByNumber(yaffs_Device * dev, __u32 number)
{
        int bucket = yaffs_HashFunction(number);
        struct ylist_head *i;
        yaffs_Object *in;

        ylist_for_each(i, &dev->objectBucket[bucket].list) {
                /* Look if it is in the list */
                if (i) {
                        in = ylist_entry(i, yaffs_Object, hashLink);
                        if (in->objectId == number) {
#ifdef __KERNEL__
                                /* Don't tell the VFS about this one if it is defered free */
				if (in->deferedFree)
					return NULL;
#endif

				return in;
			}
		}
	}

	return NULL;
}

yaffs_Object *yaffs_CreateNewObject(yaffs_Device * dev, int number,
				    yaffs_ObjectType type)
{

	yaffs_Object *theObject;
	yaffs_Tnode *tn = NULL;

	if (number < 0) {
		number = yaffs_CreateNewObjectNumber(dev);
	}

	theObject = yaffs_AllocateEmptyObject(dev);
	if(!theObject)
		return NULL;
		
	if(type == YAFFS_OBJECT_TYPE_FILE){
		tn = yaffs_GetTnode(dev);
		if(!tn){
			yaffs_FreeObject(theObject);
			return NULL;
		}
	}
		
	

	if (theObject) {
		theObject->fake = 0;
		theObject->renameAllowed = 1;
		theObject->unlinkAllowed = 1;
		theObject->objectId = number;
		yaffs_HashObject(theObject);
		theObject->variantType = type;
#ifdef CONFIG_YAFFS_WINCE
		yfsd_WinFileTimeNow(theObject->win_atime);
		theObject->win_ctime[0] = theObject->win_mtime[0] =
		    theObject->win_atime[0];
		theObject->win_ctime[1] = theObject->win_mtime[1] =
		    theObject->win_atime[1];

#else

		theObject->yst_atime = theObject->yst_mtime =
		    theObject->yst_ctime = Y_CURRENT_TIME;
#endif

#if 0
		theObject->sum_prev = 12345;
		theObject->sum_trailer = 6789;
#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 = tn;
                        break;
                case YAFFS_OBJECT_TYPE_DIRECTORY:
                        YINIT_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));
		if(newStr)
			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;
	YCHAR *str = NULL;

	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)
		return YAFFS_FAIL;
	
	if(type == YAFFS_OBJECT_TYPE_SYMLINK){
		str = yaffs_CloneString(aliasString);
		if(!str){
			yaffs_FreeObject(in);
			return NULL;
		}
	}
	
	

	if (in) {
		in->hdrChunk = 0;
		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 = str;
			break;
		case YAFFS_OBJECT_TYPE_HARDLINK:
			in->variant.hardLinkVariant.equivalentObject =
                            equivalentObject;
                        in->variant.hardLinkVariant.equivalentObjectId =
                            equivalentObject->objectId;
                        ylist_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
		   ("tragedy: 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=NULL;
	yaffs_Object *existingTarget=NULL;
	int force = 0;
	
	
	if(!oldDir || oldDir->variantType != YAFFS_OBJECT_TYPE_DIRECTORY)
		YBUG();
	if(!newDir || newDir->variantType != YAFFS_OBJECT_TYPE_DIRECTORY)
		YBUG();

#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

	else if (yaffs_strlen(newName) > YAFFS_MAX_NAME_LENGTH)
	  /* ENAMETOOLONG */
	  return YAFFS_FAIL;

	obj = yaffs_FindObjectByName(oldDir, oldName);

	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 &&
                    !ylist_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->blockInfo = NULL;
	dev->chunkBits = NULL;
	
	dev->allocationBlock = -1;	/* force it to get a new one */

	/* If the first allocation strategy fails, thry the alternate one */
	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;
		
	if(dev->blockInfo){
	
		/* 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 && dev->blockInfo)
		YFREE_ALT(dev->blockInfo);
	else if(dev->blockInfo)
		YFREE(dev->blockInfo);

	dev->blockInfoAlt = 0;

	dev->blockInfo = NULL;
	
	if(dev->chunkBitsAlt && dev->chunkBits)
		YFREE_ALT(dev->chunkBits);
	else if(dev->chunkBits)
		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 = 0;
	int prioritised=0;
	yaffs_BlockInfo *bi;
	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);
			//yaffs_VerifyBlock(dev,bi,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 t