yaffs_guts.c

yaffs２设备驱动

		int i;
		for (i = 0; i < dev->nChunksPerBlock; i++) {
			if (!yaffs_CheckChunkErased
			    (dev, blockNo * dev->nChunksPerBlock + i)) {
				T(YAFFS_TRACE_ERROR,
				  (TSTR
				   (">>Block %d erasure supposedly OK, but chunk %d not erased"
				    TENDSTR), blockNo, i));
			}
		}
	}

	if (erasedOk) {
		/* Clean it up... */
		bi->blockState = YAFFS_BLOCK_STATE_EMPTY;
		dev->nErasedBlocks++;
		bi->pagesInUse = 0;
		bi->softDeletions = 0;
		bi->hasShrinkHeader = 0;
		bi->skipErasedCheck = 1;  /* This is clean, so no need to check */
		bi->gcPrioritise = 0;
		yaffs_ClearChunkBits(dev, blockNo);

		T(YAFFS_TRACE_ERASE,
		  (TSTR("Erased block %d" TENDSTR), blockNo));
	} else {
		dev->nFreeChunks -= dev->nChunksPerBlock;	/* We lost a block of free space */

		yaffs_RetireBlock(dev, blockNo);
		T(YAFFS_TRACE_ERROR | YAFFS_TRACE_BAD_BLOCKS,
		  (TSTR("**>> Block %d retired" TENDSTR), blockNo));
	}
}

static int yaffs_FindBlockForAllocation(yaffs_Device * dev)
{
	int i;

	yaffs_BlockInfo *bi;

	if (dev->nErasedBlocks < 1) {
		/* Hoosterman we've got a problem.
		 * Can't get space to gc
		 */
		T(YAFFS_TRACE_ERROR,
		  (TSTR("yaffs tragedy: no more eraased blocks" TENDSTR)));

		return -1;
	}
	
	/* Find an empty block. */

	for (i = dev->internalStartBlock; i <= dev->internalEndBlock; i++) {
		dev->allocationBlockFinder++;
		if (dev->allocationBlockFinder < dev->internalStartBlock
		    || dev->allocationBlockFinder > dev->internalEndBlock) {
			dev->allocationBlockFinder = dev->internalStartBlock;
		}

		bi = yaffs_GetBlockInfo(dev, dev->allocationBlockFinder);

		if (bi->blockState == YAFFS_BLOCK_STATE_EMPTY) {
			bi->blockState = YAFFS_BLOCK_STATE_ALLOCATING;
			dev->sequenceNumber++;
			bi->sequenceNumber = dev->sequenceNumber;
			dev->nErasedBlocks--;
			T(YAFFS_TRACE_ALLOCATE,
			  (TSTR("Allocated block %d, seq  %d, %d left" TENDSTR),
			   dev->allocationBlockFinder, dev->sequenceNumber,
			   dev->nErasedBlocks));
			return dev->allocationBlockFinder;
		}
	}

	T(YAFFS_TRACE_ALWAYS,
	  (TSTR
	   ("yaffs tragedy: no more eraased blocks, but there should have been %d"
	    TENDSTR), dev->nErasedBlocks));

	return -1;
}


// Check if there's space to allocate...
// Thinks.... do we need top make this ths same as yaffs_GetFreeChunks()?
static int yaffs_CheckSpaceForAllocation(yaffs_Device * dev)
{
	int reservedChunks;
	int reservedBlocks = dev->nReservedBlocks;
	int checkpointBlocks;
	
	checkpointBlocks =  dev->nCheckpointReservedBlocks - dev->blocksInCheckpoint;
	if(checkpointBlocks < 0)
		checkpointBlocks = 0;
	
	reservedChunks = ((reservedBlocks + checkpointBlocks) * dev->nChunksPerBlock);
	
	return (dev->nFreeChunks > reservedChunks);
}

static int yaffs_AllocateChunk(yaffs_Device * dev, int useReserve, yaffs_BlockInfo **blockUsedPtr)
{
	int retVal;
	yaffs_BlockInfo *bi;

	if (dev->allocationBlock < 0) {
		/* Get next block to allocate off */
		dev->allocationBlock = yaffs_FindBlockForAllocation(dev);
		dev->allocationPage = 0;
	}

	if (!useReserve && !yaffs_CheckSpaceForAllocation(dev)) {
		/* Not enough space to allocate unless we're allowed to use the reserve. */
		return -1;
	}

	if (dev->nErasedBlocks < dev->nReservedBlocks
	    && dev->allocationPage == 0) {
		T(YAFFS_TRACE_ALLOCATE, (TSTR("Allocating reserve" TENDSTR)));
	}

	/* Next page please.... */
	if (dev->allocationBlock >= 0) {
		bi = yaffs_GetBlockInfo(dev, dev->allocationBlock);

		retVal = (dev->allocationBlock * dev->nChunksPerBlock) +
		    dev->allocationPage;
		bi->pagesInUse++;
		yaffs_SetChunkBit(dev, dev->allocationBlock,
				  dev->allocationPage);

		dev->allocationPage++;

		dev->nFreeChunks--;

		/* If the block is full set the state to full */
		if (dev->allocationPage >= dev->nChunksPerBlock) {
			bi->blockState = YAFFS_BLOCK_STATE_FULL;
			dev->allocationBlock = -1;
		}

		if(blockUsedPtr)
			*blockUsedPtr = bi;
			
		return retVal;
	}
	
	T(YAFFS_TRACE_ERROR,
	  (TSTR("!!!!!!!!! Allocator out !!!!!!!!!!!!!!!!!" TENDSTR)));

	return -1;
}

static int yaffs_GetErasedChunks(yaffs_Device * dev)
{
	int n;

	n = dev->nErasedBlocks * dev->nChunksPerBlock;

	if (dev->allocationBlock > 0) {
		n += (dev->nChunksPerBlock - dev->allocationPage);
	}

	return n;

}

static int yaffs_GarbageCollectBlock(yaffs_Device * dev, int block)
{
	int oldChunk;
	int newChunk;
	int chunkInBlock;
	int markNAND;
	int retVal = YAFFS_OK;
	int cleanups = 0;
	int i;
	int isCheckpointBlock;

	int chunksBefore = yaffs_GetErasedChunks(dev);
	int chunksAfter;

	yaffs_ExtendedTags tags;

	yaffs_BlockInfo *bi = yaffs_GetBlockInfo(dev, block);

	yaffs_Object *object;

	isCheckpointBlock = (bi->blockState == YAFFS_BLOCK_STATE_CHECKPOINT);
	
	bi->blockState = YAFFS_BLOCK_STATE_COLLECTING;

	T(YAFFS_TRACE_TRACING,
	  (TSTR("Collecting block %d, in use %d, shrink %d, " TENDSTR), block,
	   bi->pagesInUse, bi->hasShrinkHeader));

	/*yaffs_VerifyFreeChunks(dev); */

	bi->hasShrinkHeader = 0;	/* clear the flag so that the block can erase */

	/* Take off the number of soft deleted entries because
	 * they're going to get really deleted during GC.
	 */
	dev->nFreeChunks -= bi->softDeletions;

	dev->isDoingGC = 1;

	if (isCheckpointBlock ||
	    !yaffs_StillSomeChunkBits(dev, block)) {
		T(YAFFS_TRACE_TRACING,
		  (TSTR
		   ("Collecting block %d that has no chunks in use" TENDSTR),
		   block));
		yaffs_BlockBecameDirty(dev, block);
	} else {

		__u8 *buffer = yaffs_GetTempBuffer(dev, __LINE__);

		for (chunkInBlock = 0, oldChunk = block * dev->nChunksPerBlock;
		     chunkInBlock < dev->nChunksPerBlock
		     && yaffs_StillSomeChunkBits(dev, block);
		     chunkInBlock++, oldChunk++) {
			if (yaffs_CheckChunkBit(dev, block, chunkInBlock)) {

				/* This page is in use and might need to be copied off */

				markNAND = 1;

				yaffs_InitialiseTags(&tags);

				yaffs_ReadChunkWithTagsFromNAND(dev, oldChunk,
								buffer, &tags);

				object =
				    yaffs_FindObjectByNumber(dev,
							     tags.objectId);

				T(YAFFS_TRACE_GC_DETAIL,
				  (TSTR
				   ("Collecting page %d, %d %d %d " TENDSTR),
				   chunkInBlock, tags.objectId, tags.chunkId,
				   tags.byteCount));

				if (!object) {
					T(YAFFS_TRACE_ERROR,
					  (TSTR
					   ("page %d in gc has no object "
					    TENDSTR), oldChunk));
				}

				if (object && object->deleted
				    && tags.chunkId != 0) {
					/* Data chunk in a deleted file, throw it away
					 * It's a soft deleted data chunk,
					 * No need to copy this, just forget about it and 
					 * fix up the object.
					 */

					object->nDataChunks--;

					if (object->nDataChunks <= 0) {
						/* remeber to clean up the object */
						dev->gcCleanupList[cleanups] =
						    tags.objectId;
						cleanups++;
					}
					markNAND = 0;
				} else if (0
					   /* Todo object && object->deleted && object->nDataChunks == 0 */
					   ) {
					/* Deleted object header with no data chunks.
					 * Can be discarded and the file deleted.
					 */
					object->chunkId = 0;
					yaffs_FreeTnode(object->myDev,
							object->variant.
							fileVariant.top);
					object->variant.fileVariant.top = NULL;
					yaffs_DoGenericObjectDeletion(object);

				} else if (object) {
					/* It's either a data chunk in a live file or
					 * an ObjectHeader, so we're interested in it.
					 * NB Need to keep the ObjectHeaders of deleted files
					 * until the whole file has been deleted off
					 */
					tags.serialNumber++;

					dev->nGCCopies++;

					if (tags.chunkId == 0) {
						/* It is an object Id,
						 * We need to nuke the shrinkheader flags first
						 * We no longer want the shrinkHeader flag since its work is done
						 * and if it is left in place it will mess up scanning.
						 * Also, clear out any shadowing stuff
						 */

						yaffs_ObjectHeader *oh;
						oh = (yaffs_ObjectHeader *)buffer;
						oh->isShrink = 0;
						oh->shadowsObject = -1;
						tags.extraShadows = 0;
						tags.extraIsShrinkHeader = 0;
					}

					newChunk =
					    yaffs_WriteNewChunkWithTagsToNAND(dev, buffer, &tags, 1);

					if (newChunk < 0) {
						retVal = YAFFS_FAIL;
					} else {

						/* Ok, now fix up the Tnodes etc. */

						if (tags.chunkId == 0) {
							/* It's a header */
							object->chunkId =  newChunk;
							object->serial =   tags.serialNumber;
						} else {
							/* It's a data chunk */
							yaffs_PutChunkIntoFile
							    (object,
							     tags.chunkId,
							     newChunk, 0);
						}
					}
				}

				yaffs_DeleteChunk(dev, oldChunk, markNAND, __LINE__);

			}
		}

		yaffs_ReleaseTempBuffer(dev, buffer, __LINE__);


		/* Do any required cleanups */
		for (i = 0; i < cleanups; i++) {
			/* Time to delete the file too */
			object =
			    yaffs_FindObjectByNumber(dev,
						     dev->gcCleanupList[i]);
			if (object) {
				yaffs_FreeTnode(dev,
						object->variant.fileVariant.
						top);
				object->variant.fileVariant.top = NULL;
				T(YAFFS_TRACE_GC,
				  (TSTR
				   ("yaffs: About to finally delete object %d"
				    TENDSTR), object->objectId));
				yaffs_DoGenericObjectDeletion(object);
				object->myDev->nDeletedFiles--;
			}

		}

	}

	if (chunksBefore >= (chunksAfter = yaffs_GetErasedChunks(dev))) {
		T(YAFFS_TRACE_GC,
		  (TSTR
		   ("gc did not increase free chunks before %d after %d"
		    TENDSTR), chunksBefore, chunksAfter));
	}

	dev->isDoingGC = 0;

	return YAFFS_OK;
}

/* New garbage collector
 * If we're very low on erased blocks then we do aggressive garbage collection
 * otherwise we do "leasurely" garbage collection.
 * Aggressive gc looks further (whole array) and will accept less dirty blocks.
 * Passive gc only inspects smaller areas and will only accept more dirty blocks.
 *
 * The idea is to help clear out space in a more spread-out manner.
 * Dunno if it really does anything useful.
 */
static int yaffs_CheckGarbageCollection(yaffs_Device * dev)
{
	int block;
	int aggressive;
	int gcOk = YAFFS_OK;
	int maxTries = 0;
	
	int checkpointBlockAdjust;

	if (dev->isDoingGC) {
		/* Bail out so we don't get recursive gc */
		return YAFFS_OK;
	}
	
	/* This loop should pass the first time.
	 * We'll only see looping here if the erase of the collected block fails.
	 */

	do {
		maxTries++;
		
		checkpointBlockAdjust = (dev->nCheckpointReservedBlocks - dev->blocksInCheckpoint);
		if(checkpointBlockAdjust < 0)
			checkpointBlockAdjust = 0;

		if (dev->nErasedBlocks < (dev->nReservedBlocks + checkpointBlockAdjust)) {
			/* We need a block soon...*/
			aggressive = 1;
		} else {
			/* We're in no hurry */
			aggressive = 0;
		}

		block = yaffs_FindBlockForGarbageCollection(dev, aggressive);

		if (block > 0) {
			dev->garbageCollections++;
			if (!aggressive) {
				dev->passiveGarbageCollections++;
			}

			T(YAFFS_TRACE_GC,
			  (TSTR
			   ("yaffs: GC erasedBlocks %d aggressive %d" TENDSTR),
			   dev->nErasedBlocks, aggressive));

			gcOk = yaffs_GarbageCollectBlock(dev, block);
		}

		if (dev->nErasedBlocks < (dev->nReservedBlocks) && block > 0) {
			T(YAFFS_TRACE_GC,
			  (TSTR
			   ("yaffs: GC !!!no reclaim!!! erasedBlocks %d after try %d block %d"
			    TENDSTR), dev->nErasedBlocks, maxTries, block));
		}
	} while ((dev->nErasedBlocks < dev->nReservedBlocks) && (block > 0)
		 && (maxTries < 2));

	return aggressive ? gcOk : YAFFS_OK;
}

/*-------------------------  TAGS --------------------------------*/

static int yaffs_TagsMatch(const yaffs_ExtendedTags * tags, int objectId,
			   int chunkInObject)
{
	return (tags->chunkId == chunkInObject &&
		tags->objectId == objectId && !tags->chunkDeleted) ? 1 : 0;

}


/*-------------------- Data file manipulation -----------------*/

static int yaffs_FindChunkInFile(yaffs_Object * in, int chunkInInode,
				 yaffs_ExtendedTags * tags)
{
	/*Get the Tnode, then get the level 0 offset chunk offset */
	yaffs_Tnode *tn;
	int theChunk = -1;
	yaffs_ExtendedTags localTags;
	int retVal = -1;

	yaffs_Device *dev = in->myDev;

	if (!tags) {
		/* Passed a NULL, so use our own tags space */
		tags = &localTags;
	}

	tn = yaffs_FindLevel0Tnode(dev, &in->variant.fileVariant, chunkInInode);

	if (tn) {
		theChunk = yaffs_GetChunkGroupBase(dev,tn,chunkInInode);

		retVal =
		    yaffs_FindChunkInGroup(dev, theChunk, tags, in->objectId,
					   chunkInInode);
	}
	return retVal;
}

static int yaffs_FindAndDeleteChunkInFile(yaffs_Object * in, int chunkInInode,
					  yaffs_ExtendedTags * tags)
{
	/* Get the Tnode, then get the level 0 offset chunk offset */
	yaffs_Tnode *tn;
	int theChunk = -1;
	yaffs_ExtendedTags localTags;

	yaffs_Device *dev = in->myDev;
	int retVal = -1;

	if (!tags) {
		/* Passed a NULL, so use our own tags space */
		tags = &localTags;
	}

	tn = yaffs_FindLevel0Tnode(dev, &in->variant.fileVariant, chunkInInode);

	if (tn) {

		theChunk = yaffs_GetChunkGroupBase(dev,tn,chunkInInode);

		retVal =
		    yaffs_FindChunkInGroup(dev, theChunk, tags, in->objectId,
					   chunkInInode);

		/* Delete the entry in the filestructure (if found) */
		if (retVal != -1) {
			yaffs_PutLevel0Tnode(dev,tn,chunkInInode,0);
		}
	} else {
		/*T(("No level 0 found for %d\n", chunkInInode)); */
	}

	if (retVal == -1) {
		/* T(("Could not find %d to delete\n",chunkInInode)); */
	}
	return retVal;
}

#ifdef YAFFS_PARANOID

static int yaffs_CheckFileSanity(yaffs_Object * in)
{
	int chunk;
	int nChunks;
	int fSize;
	int failed = 0;
	int objId;
	yaffs_Tnode *tn;
	yaffs_Tags localTags;
	yaffs_Tags *tags = &localTags;
	int theChunk;
	int chunkDeleted;

	if (in->variantType != YAFFS_OBJECT_TYPE_FILE) {
		/* T(("Objec