yaffs_guts.c

YAFFS

static void yaffs_SoftDeleteFile(yaffs_Object * obj)
{
	if (obj->deleted &&
	    obj->variantType == YAFFS_OBJECT_TYPE_FILE && !obj->softDeleted) {
		if (obj->nDataChunks <= 0) {
			/* Empty file with no duplicate object headers, just delete it immediately */
			yaffs_FreeTnode(obj->myDev,
					obj->variant.fileVariant.top);
			obj->variant.fileVariant.top = NULL;
			T(YAFFS_TRACE_TRACING,
			  (TSTR("yaffs: Deleting empty file %d" TENDSTR),
			   obj->objectId));
			yaffs_DoGenericObjectDeletion(obj);
		} else {
			yaffs_SoftDeleteWorker(obj,
					       obj->variant.fileVariant.top,
					       obj->variant.fileVariant.
					       topLevel, 0);
			obj->softDeleted = 1;
		}
	}
}

/* Pruning removes any part of the file structure tree that is beyond the
 * bounds of the file (ie that does not point to chunks).
 *
 * A file should only get pruned when its size is reduced.
 *
 * Before pruning, the chunks must be pulled from the tree and the
 * level 0 tnode entries must be zeroed out.
 * Could also use this for file deletion, but that's probably better handled
 * by a special case.
 */

static yaffs_Tnode *yaffs_PruneWorker(yaffs_Device * dev, yaffs_Tnode * tn,
				      __u32 level, int del0)
{
	int i;
	int hasData;

	if (tn) {
		hasData = 0;

		for (i = 0; i < YAFFS_NTNODES_INTERNAL; i++) {
			if (tn->internal[i] && level > 0) {
				tn->internal[i] =
				    yaffs_PruneWorker(dev, tn->internal[i],
						      level - 1,
						      (i == 0) ? del0 : 1);
			}

			if (tn->internal[i]) {
				hasData++;
			}
		}

		if (hasData == 0 && del0) {
			/* Free and return NULL */

			yaffs_FreeTnode(dev, tn);
			tn = NULL;
		}

	}

	return tn;

}

static int yaffs_PruneFileStructure(yaffs_Device * dev,
				    yaffs_FileStructure * fStruct)
{
	int i;
	int hasData;
	int done = 0;
	yaffs_Tnode *tn;

	if (fStruct->topLevel > 0) {
		fStruct->top =
		    yaffs_PruneWorker(dev, fStruct->top, fStruct->topLevel, 0);

		/* Now we have a tree with all the non-zero branches NULL but the height
		 * is the same as it was.
		 * Let's see if we can trim internal tnodes to shorten the tree.
		 * We can do this if only the 0th element in the tnode is in use 
		 * (ie all the non-zero are NULL)
		 */

		while (fStruct->topLevel && !done) {
			tn = fStruct->top;

			hasData = 0;
			for (i = 1; i < YAFFS_NTNODES_INTERNAL; i++) {
				if (tn->internal[i]) {
					hasData++;
				}
			}

			if (!hasData) {
				fStruct->top = tn->internal[0];
				fStruct->topLevel--;
				yaffs_FreeTnode(dev, tn);
			} else {
				done = 1;
			}
		}
	}

	return YAFFS_OK;
}

/*-------------------- End of File Structure functions.-------------------*/

/* yaffs_CreateFreeObjects creates a bunch more objects and
 * adds them to the object free list.
 */
static int yaffs_CreateFreeObjects(yaffs_Device * dev, int nObjects)
{
	int i;
	yaffs_Object *newObjects;
	yaffs_ObjectList *list;

	if (nObjects < 1)
		return YAFFS_OK;

	/* make these things */
	newObjects = YMALLOC(nObjects * sizeof(yaffs_Object));

	if (!newObjects) {
		T(YAFFS_TRACE_ALLOCATE,
		  (TSTR("yaffs: Could not allocate more objects" TENDSTR)));
		return YAFFS_FAIL;
	}
	
	/* Hook them into the free list */
	for (i = 0; i < nObjects - 1; i++) {
		newObjects[i].siblings.next =
		    (struct list_head *)(&newObjects[i + 1]);
	}

	newObjects[nObjects - 1].siblings.next = (void *)dev->freeObjects;
	dev->freeObjects = newObjects;
	dev->nFreeObjects += nObjects;
	dev->nObjectsCreated += nObjects;

	/* Now add this bunch of Objects to a list for freeing up. */

	list = YMALLOC(sizeof(yaffs_ObjectList));
	if (!list) {
		T(YAFFS_TRACE_ALLOCATE,
		  (TSTR("Could not add objects to management list" TENDSTR)));
	} else {
		list->objects = newObjects;
		list->next = dev->allocatedObjectList;
		dev->allocatedObjectList = list;
	}

	return YAFFS_OK;
}


/* AllocateEmptyObject gets us a clean Object. Tries to make allocate more if we run out */
static yaffs_Object *yaffs_AllocateEmptyObject(yaffs_Device * dev)
{
	yaffs_Object *tn = NULL;

	/* If there are none left make more */
	if (!dev->freeObjects) {
		yaffs_CreateFreeObjects(dev, YAFFS_ALLOCATION_NOBJECTS);
	}

	if (dev->freeObjects) {
		tn = dev->freeObjects;
		dev->freeObjects =
		    (yaffs_Object *) (dev->freeObjects->siblings.next);
		dev->nFreeObjects--;

		/* Now sweeten it up... */

		memset(tn, 0, sizeof(yaffs_Object));
		tn->myDev = dev;
		tn->chunkId = -1;
		tn->variantType = YAFFS_OBJECT_TYPE_UNKNOWN;
		INIT_LIST_HEAD(&(tn->hardLinks));
		INIT_LIST_HEAD(&(tn->hashLink));
		INIT_LIST_HEAD(&tn->siblings);

		/* Add it to the lost and found directory.
		 * NB Can't put root or lostNFound in lostNFound so
		 * check if lostNFound exists first
		 */
		if (dev->lostNFoundDir) {
			yaffs_AddObjectToDirectory(dev->lostNFoundDir, tn);
		}
	}

	return tn;
}

static yaffs_Object *yaffs_CreateFakeDirectory(yaffs_Device * dev, int number,
					       __u32 mode)
{

	yaffs_Object *obj =
	    yaffs_CreateNewObject(dev, number, YAFFS_OBJECT_TYPE_DIRECTORY);
	if (obj) {
		obj->fake = 1;		/* it is fake so it has no NAND presence... */
		obj->renameAllowed = 0;	/* ... and we're not allowed to rename it... */
		obj->unlinkAllowed = 0;	/* ... or unlink it */
		obj->deleted = 0;
		obj->unlinked = 0;
		obj->yst_mode = mode;
		obj->myDev = dev;
		obj->chunkId = 0;	/* Not a valid chunk. */
	}

	return obj;

}

static void yaffs_UnhashObject(yaffs_Object * tn)
{
	int bucket;
	yaffs_Device *dev = tn->myDev;

	/* If it is still linked into the bucket list, free from the list */
	if (!list_empty(&tn->hashLink)) {
		list_del_init(&tn->hashLink);
		bucket = yaffs_HashFunction(tn->objectId);
		dev->objectBucket[bucket].count--;
	}

}

/*  FreeObject frees up a Object and puts it back on the free list */
static void yaffs_FreeObject(yaffs_Object * tn)
{

	yaffs_Device *dev = tn->myDev;

#ifdef  __KERNEL__
	if (tn->myInode) {
		/* We're still hooked up to a cached inode.
		 * Don't delete now, but mark for later deletion
		 */
		tn->deferedFree = 1;
		return;
	}
#endif

	yaffs_UnhashObject(tn);

	/* Link into the free list. */
	tn->siblings.next = (struct list_head *)(dev->freeObjects);
	dev->freeObjects = tn;
	dev->nFreeObjects++;
}

#ifdef __KERNEL__

void yaffs_HandleDeferedFree(yaffs_Object * obj)
{
	if (obj->deferedFree) {
		yaffs_FreeObject(obj);
	}
}

#endif

static void yaffs_DeinitialiseObjects(yaffs_Device * dev)
{
	/* Free the list of allocated Objects */

	yaffs_ObjectList *tmp;

	while (dev->allocatedObjectList) {
		tmp = dev->allocatedObjectList->next;
		YFREE(dev->allocatedObjectList->objects);
		YFREE(dev->allocatedObjectList);

		dev->allocatedObjectList = tmp;
	}

	dev->freeObjects = NULL;
	dev->nFreeObjects = 0;
}

static void yaffs_InitialiseObjects(yaffs_Device * dev)
{
	int i;

	dev->allocatedObjectList = NULL;
	dev->freeObjects = NULL;
	dev->nFreeObjects = 0;

	for (i = 0; i < YAFFS_NOBJECT_BUCKETS; i++) {
		INIT_LIST_HEAD(&dev->objectBucket[i].list);
		dev->objectBucket[i].count = 0;
	}

}

static int yaffs_FindNiceObjectBucket(yaffs_Device * dev)
{
	static int x = 0;
	int i;
	int l = 999;
	int lowest = 999999;

	/* First let's see if we can find one that's empty. */

	for (i = 0; i < 10 && lowest > 0; i++) {
		x++;
		x %= YAFFS_NOBJECT_BUCKETS;
		if (dev->objectBucket[x].count < lowest) {
			lowest = dev->objectBucket[x].count;
			l = x;
		}

	}

	/* If we didn't find an empty list, then try
	 * looking a bit further for a short one
	 */

	for (i = 0; i < 10 && lowest > 3; i++) {
		x++;
		x %= YAFFS_NOBJECT_BUCKETS;
		if (dev->objectBucket[x].count < lowest) {
			lowest = dev->objectBucket[x].count;
			l = x;
		}

	}

	return l;
}

static int yaffs_CreateNewObjectNumber(yaffs_Device * dev)
{
	int bucket = yaffs_FindNiceObjectBucket(dev);

	/* Now find an object value that has not already been taken
	 * by scanning the list.
	 */

	int found = 0;
	struct list_head *i;

	__u32 n = (__u32) bucket;

	/* yaffs_CheckObjectHashSanity();  */

	while (!found) {
		found = 1;
		n += YAFFS_NOBJECT_BUCKETS;
		if (1 || dev->objectBucket[bucket].count > 0) {
			list_for_each(i, &dev->objectBucket[bucket].list) {
				/* If there is already one in the list */
				if (i
				    && list_entry(i, yaffs_Object,
						  hashLink)->objectId == n) {
					found = 0;
				}
			}
		}
	}


	return n;
}

static void yaffs_HashObject(yaffs_Object * in)
{
	int bucket = yaffs_HashFunction(in->objectId);
	yaffs_Device *dev = in->myDev;

	list_add(&in->hashLink, &dev->objectBucket[bucket].list);
	dev->objectBucket[bucket].count++;

}

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

	list_for_each(i, &dev->objectBucket[bucket].list) {
		/* Look if it is in the list */
		if (i) {
			in = list_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;

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

	theObject = yaffs_AllocateEmptyObject(dev);

	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
		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;