+ /* 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" : ""));
+
+ yaffs_ClearOldestDirtySequence(dev,bi);
+
+ bi->blockState = YAFFS_BLOCK_STATE_DIRTY;
+
+ /* If this is the block being garbage collected then stop gc'ing this block */
+ if(blockNo == dev->gcBlock)
+ dev->gcBlock = 0;
+
+ /* If this block is currently the best candidate for gc then drop as a candidate */
+ if(blockNo == dev->gcDirtiest){
+ dev->gcDirtiest = 0;
+ dev->gcPagesInUse = 0;
+ }
+
+ 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) || !yaffs_SkipVerification(dev))) {
+ int i;
+ for (i = 0; i < dev->param.nChunksPerBlock; i++) {
+ if (!yaffs_CheckChunkErased
+ (dev, blockNo * dev->param.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;
+ bi->sequenceNumber = 0;
+ 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->param.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 erased 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 erased blocks, but there should have been %d"
+ TENDSTR), dev->nErasedBlocks));
+
+ return -1;
+}
+
+
+
+static int yaffs_CheckpointRequired(yaffs_Device *dev)
+{
+ int nblocks = dev->internalEndBlock - dev->internalStartBlock + 1 ;
+ return dev->param.isYaffs2 &&
+ !dev->param.skipCheckpointWrite &&
+ (nblocks >= YAFFS_CHECKPOINT_MIN_BLOCKS);
+}
+static int yaffs_CalcCheckpointBlocksRequired(yaffs_Device *dev)
+{
+ if (!dev->nCheckpointBlocksRequired &&
+ yaffs_CheckpointRequired(dev)){
+ /* Not a valid value so recalculate */
+ int nBytes = 0;
+ int nBlocks;
+ int devBlocks = (dev->param.endBlock - dev->param.startBlock + 1);
+ int tnodeSize = yaffs_CalcTnodeSize(dev);
+
+ nBytes += sizeof(yaffs_CheckpointValidity);
+ nBytes += sizeof(yaffs_CheckpointDevice);
+ nBytes += devBlocks * sizeof(yaffs_BlockInfo);
+ nBytes += devBlocks * dev->chunkBitmapStride;
+ nBytes += (sizeof(yaffs_CheckpointObject) + sizeof(__u32)) * (dev->nObjectsCreated - dev->nFreeObjects);
+ nBytes += (tnodeSize + sizeof(__u32)) * (dev->nTnodesCreated - dev->nFreeTnodes);
+ nBytes += sizeof(yaffs_CheckpointValidity);
+ nBytes += sizeof(__u32); /* checksum*/
+
+ /* Round up and add 2 blocks to allow for some bad blocks, so add 3 */
+
+ nBlocks = (nBytes/(dev->nDataBytesPerChunk * dev->param.nChunksPerBlock)) + 3;
+
+ dev->nCheckpointBlocksRequired = nBlocks;
+ }
+
+ return dev->nCheckpointBlocksRequired;
+}
+
+/*
+ * 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 nChunks)
+{
+ int reservedChunks;
+ int reservedBlocks = dev->param.nReservedBlocks;
+ int checkpointBlocks;
+
+ if (dev->param.isYaffs2) {
+ checkpointBlocks = yaffs_CalcCheckpointBlocksRequired(dev) -
+ dev->blocksInCheckpoint;
+ if (checkpointBlocks < 0)
+ checkpointBlocks = 0;
+ } else {
+ checkpointBlocks = 0;
+ }
+
+ reservedChunks = ((reservedBlocks + checkpointBlocks) * dev->param.nChunksPerBlock);
+
+ return (dev->nFreeChunks > (reservedChunks + nChunks));
+}
+
+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, 1)) {
+ /* Not enough space to allocate unless we're allowed to use the reserve. */
+ return -1;
+ }
+
+ if (dev->nErasedBlocks < dev->param.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->param.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->param.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->param.nChunksPerBlock;
+
+ if (dev->allocationBlock > 0)
+ n += (dev->param.nChunksPerBlock - dev->allocationPage);
+
+ return n;
+
+}
+
+/*
+ * yaffs_SkipRestOfBlock() skips over the rest of the allocation block
+ * if we don't want to write to it.
+ */
+static void yaffs_SkipRestOfBlock(yaffs_Device *dev)
+{
+ if(dev->allocationBlock > 0){
+ yaffs_BlockInfo *bi = yaffs_GetBlockInfo(dev, dev->allocationBlock);
+ if(bi->blockState == YAFFS_BLOCK_STATE_ALLOCATING){
+ bi->blockState = YAFFS_BLOCK_STATE_FULL;
+ dev->allocationBlock = -1;
+ }
+ }
+}
+
+
+static int yaffs_GarbageCollectBlock(yaffs_Device *dev, int block,
+ int wholeBlock)
+{
+ int oldChunk;
+ int newChunk;
+ int markNAND;
+ int retVal = YAFFS_OK;
+ int cleanups = 0;
+ int i;
+ int isCheckpointBlock;
+ int matchingChunk;
+ int maxCopies;
+
+ 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);
+
+
+ T(YAFFS_TRACE_TRACING,
+ (TSTR("Collecting block %d, in use %d, shrink %d, wholeBlock %d" TENDSTR),
+ block,
+ bi->pagesInUse,
+ bi->hasShrinkHeader,
+ wholeBlock));
+
+ /*yaffs_VerifyFreeChunks(dev); */
+
+ if(bi->blockState == YAFFS_BLOCK_STATE_FULL)
+ bi->blockState = YAFFS_BLOCK_STATE_COLLECTING;
+
+ bi->hasShrinkHeader = 0; /* clear the flag so that the block can erase */
+
+ dev->gcDisable = 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__);
+
+ yaffs_VerifyBlock(dev, bi, block);
+
+ maxCopies = (wholeBlock) ? dev->param.nChunksPerBlock : 5;
+ oldChunk = block * dev->param.nChunksPerBlock + dev->gcChunk;
+
+ for (/* init already done */;
+ retVal == YAFFS_OK &&
+ dev->gcChunk < dev->param.nChunksPerBlock &&
+ (bi->blockState == YAFFS_BLOCK_STATE_COLLECTING) &&
+ maxCopies > 0;
+ dev->gcChunk++, oldChunk++) {
+ if (yaffs_CheckChunkBit(dev, block, dev->gcChunk)) {
+
+ /* This page is in use and might need to be copied off */
+
+ maxCopies--;
+
+ markNAND = 1;
+
+ yaffs_InitialiseTags(&tags);
+
+ yaffs_ReadChunkWithTagsFromNAND(dev, oldChunk,
+ buffer, &tags);
+
+ object =
+ yaffs_FindObjectByNumber(dev,
+ tags.objectId);
+
+ T(YAFFS_TRACE_GC_DETAIL,
+ (TSTR
+ ("Collecting chunk in block %d, %d %d %d " TENDSTR),
+ dev->gcChunk, tags.objectId, tags.chunkId,
+ tags.byteCount));
+
+ if (object && !yaffs_SkipVerification(dev)) {
+ if (tags.chunkId == 0)
+ matchingChunk = object->hdrChunk;
+ else if (object->softDeleted)
+ matchingChunk = oldChunk; /* Defeat the test */
+ else
+ matchingChunk = yaffs_FindChunkInFile(object, tags.chunkId, NULL);
+
+ if (oldChunk != matchingChunk)
+ T(YAFFS_TRACE_ERROR,
+ (TSTR("gc: page in gc mismatch: %d %d %d %d"TENDSTR),
+ oldChunk, matchingChunk, tags.objectId, tags.chunkId));
+
+ }
+
+ if (!object) {
+ T(YAFFS_TRACE_ERROR,
+ (TSTR
+ ("page %d in gc has no object: %d %d %d "
+ TENDSTR), oldChunk,
+ tags.objectId, tags.chunkId, tags.byteCount));
+ }
+
+ if (object &&
+ object->deleted &&
+ object->softDeleted &&
+ tags.chunkId != 0) {
+ /* Data chunk in a soft 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.
+ */
+
+ /* Free chunks already includes softdeleted chunks.
+ * How ever this chunk is going to soon be really deleted
+ * which will increment free chunks.
+ * We have to decrement free chunks so this works out properly.
+ */
+ dev->nFreeChunks--;
+
+ 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->hdrChunk = 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
+ * Also need to clean up shadowing.
+ * We no longer want the shrinkHeader flag since its work is done
+ * and if it is left in place it will mess up scanning.
+ */
+
+ yaffs_ObjectHeader *oh;
+ oh = (yaffs_ObjectHeader *)buffer;
+
+ oh->isShrink = 0;
+ tags.extraIsShrinkHeader = 0;
+
+ oh->shadowsObject = 0;
+ oh->inbandShadowsObject = 0;
+ tags.extraShadows = 0;
+
+ /* Update file size */
+ if(object->variantType == YAFFS_OBJECT_TYPE_FILE){
+ oh->fileSize = object->variant.fileVariant.fileSize;
+ tags.extraFileLength = oh->fileSize;
+ }
+
+ yaffs_VerifyObjectHeader(object, oh, &tags, 1);
+ newChunk =
+ yaffs_WriteNewChunkWithTagsToNAND(dev,(__u8 *) oh, &tags, 1);
+ } else
+ 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->hdrChunk = newChunk;
+ object->serial = tags.serialNumber;
+ } else {
+ /* It's a data chunk */
+ int ok;
+ ok = yaffs_PutChunkIntoFile
+ (object,
+ tags.chunkId,
+ newChunk, 0);
+ }
+ }
+ }
+
+ if (retVal == YAFFS_OK)
+ 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--;
+ }
+
+ }
+
+ }
+
+ yaffs_VerifyCollectedBlock(dev, bi, block);
+
+
+
+ if (bi->blockState == YAFFS_BLOCK_STATE_COLLECTING) {
+ /*
+ * The gc did not complete. Set block state back to FULL
+ * because checkpointing does not restore gc.
+ */
+ bi->blockState = YAFFS_BLOCK_STATE_FULL;
+ } else {
+ /* The gc completed. */
+ chunksAfter = yaffs_GetErasedChunks(dev);
+ if (chunksBefore >= chunksAfter) {
+ T(YAFFS_TRACE_GC,
+ (TSTR
+ ("gc did not increase free chunks before %d after %d"
+ TENDSTR), chunksBefore, chunksAfter));
+ }
+ dev->gcBlock = 0;
+ dev->gcChunk = 0;
+ }
+
+ dev->gcDisable = 0;
+
+ return retVal;
+}
+
+/*
+ * FindBlockForgarbageCollection is used to select the dirtiest block (or close enough)
+ * for garbage collection.
+ */
+
+static unsigned yaffs_FindBlockForGarbageCollection(yaffs_Device *dev,
+ int aggressive,
+ int background)
+{
+ int i;
+ int iterations;
+ unsigned selected = 0;
+ int prioritised = 0;
+ int prioritisedExists = 0;
+ yaffs_BlockInfo *bi;
+ int threshold;
+
+ /* First let's see if we need to grab a prioritised block */
+ if (dev->hasPendingPrioritisedGCs && !aggressive) {
+ dev->gcDirtiest = 0;
+ bi = dev->blockInfo;
+ for (i = dev->internalStartBlock;
+ i <= dev->internalEndBlock && !selected;
+ i++) {
+
+ if (bi->gcPrioritise) {
+ prioritisedExists = 1;
+ if (bi->blockState == YAFFS_BLOCK_STATE_FULL &&
+ yaffs_BlockNotDisqualifiedFromGC(dev, bi)) {
+ selected = i;
+ prioritised = 1;
+ }
+ }
+ bi++;
+ }
+
+ /*
+ * If there is a prioritised block and none was selected then
+ * this happened because there is at least one old dirty block gumming
+ * up the works. Let's gc the oldest dirty block.
+ */
+
+ if(prioritisedExists &&
+ !selected &&
+ dev->oldestDirtyBlock > 0)
+ selected = dev->oldestDirtyBlock;
+
+ if (!prioritisedExists) /* 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.
+ */
+
+ if (!selected){
+ int pagesUsed;
+ int nBlocks = dev->internalEndBlock - dev->internalStartBlock + 1;
+ if (aggressive){
+ threshold = dev->param.nChunksPerBlock;
+ iterations = nBlocks;
+ } else {
+ int maxThreshold = dev->param.nChunksPerBlock/2;
+ threshold = background ?
+ (dev->gcNotDone + 2) * 2 : 0;
+ if(threshold <YAFFS_GC_PASSIVE_THRESHOLD)
+ threshold = YAFFS_GC_PASSIVE_THRESHOLD;
+ if(threshold > maxThreshold)
+ threshold = maxThreshold;
+
+ iterations = nBlocks / 16 + 1;
+ if (iterations > 100)
+ iterations = 100;
+ }
+
+ for (i = 0;
+ i < iterations &&
+ (dev->gcDirtiest < 1 ||
+ dev->gcPagesInUse > YAFFS_GC_GOOD_ENOUGH);
+ i++) {
+ dev->gcBlockFinder++;
+ if (dev->gcBlockFinder < dev->internalStartBlock ||
+ dev->gcBlockFinder > dev->internalEndBlock)
+ dev->gcBlockFinder = dev->internalStartBlock;
+
+ bi = yaffs_GetBlockInfo(dev, dev->gcBlockFinder);
+
+ pagesUsed = bi->pagesInUse - bi->softDeletions;
+
+ if (bi->blockState == YAFFS_BLOCK_STATE_FULL &&
+ pagesUsed < dev->param.nChunksPerBlock &&
+ (dev->gcDirtiest < 1 || pagesUsed < dev->gcPagesInUse) &&
+ yaffs_BlockNotDisqualifiedFromGC(dev, bi)) {
+ dev->gcDirtiest = dev->gcBlockFinder;
+ dev->gcPagesInUse = pagesUsed;
+ }
+ }
+
+ if(dev->gcDirtiest > 0 && dev->gcPagesInUse <= threshold)
+ selected = dev->gcDirtiest;
+ }
+
+ /*
+ * If nothing has been selected for a while, try selecting the oldest dirty
+ * because that's gumming up the works.
+ */
+
+ if(!selected && dev->param.isYaffs2 &&
+ dev->gcNotDone >= ( background ? 10 : 20)){
+ yaffs_FindOldestDirtySequence(dev);
+ if(dev->oldestDirtyBlock > 0) {
+ selected = dev->oldestDirtyBlock;
+ dev->gcDirtiest = selected;
+ dev->oldestDirtyGCs++;
+ bi = yaffs_GetBlockInfo(dev, selected);
+ dev->gcPagesInUse = bi->pagesInUse - bi->softDeletions;
+ } else
+ dev->gcNotDone = 0;
+ }
+
+ if(selected){
+ T(YAFFS_TRACE_GC,
+ (TSTR("GC Selected block %d with %d free, prioritised:%d" TENDSTR),
+ selected,
+ dev->param.nChunksPerBlock - dev->gcPagesInUse,
+ prioritised));
+
+ if(background)
+ dev->backgroundGCs++;
+ dev->gcDirtiest = 0;
+ dev->gcPagesInUse = 0;
+ dev->gcNotDone = 0;
+ if(dev->refreshSkip > 0)
+ dev->refreshSkip--;
+ } else{
+ dev->gcNotDone++;
+ T(YAFFS_TRACE_GC,
+ (TSTR("GC none: finder %d skip %d threshold %d dirtiest %d using %d oldest %d%s" TENDSTR),
+ dev->gcBlockFinder, dev->gcNotDone,
+ threshold,
+ dev->gcDirtiest, dev->gcPagesInUse,
+ dev->oldestDirtyBlock,
+ background ? " bg" : ""));
+ }
+
+ return selected;
+}
+
+/* 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 background)
+{
+ int aggressive = 0;
+ int gcOk = YAFFS_OK;
+ int maxTries = 0;
+
+ int minErased;
+ int erasedChunks;
+
+ int checkpointBlockAdjust;
+
+ if(dev->param.gcControl &&
+ (dev->param.gcControl(dev) & 1) == 0)
+ return YAFFS_OK;
+
+ if (dev->gcDisable) {
+ /* 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 collection does not increase space.
+ */
+
+ do {
+ maxTries++;
+
+ checkpointBlockAdjust = yaffs_CalcCheckpointBlocksRequired(dev) - dev->blocksInCheckpoint;
+ if (checkpointBlockAdjust < 0)
+ checkpointBlockAdjust = 0;
+
+ minErased = dev->param.nReservedBlocks + checkpointBlockAdjust + 1;
+ erasedChunks = dev->nErasedBlocks * dev->param.nChunksPerBlock;
+
+ /* If we need a block soon then do aggressive gc.*/
+ if (dev->nErasedBlocks < minErased)
+ aggressive = 1;
+ else {
+ if(dev->gcSkip > 20)
+ dev->gcSkip = 20;
+ if(erasedChunks < dev->nFreeChunks/2 ||
+ dev->gcSkip < 1 ||
+ background)
+ aggressive = 0;
+ else {
+ dev->gcSkip--;
+ break;
+ }
+ }
+
+ dev->gcSkip = 5;
+
+ /* If we don't already have a block being gc'd then see if we should start another */
+
+ if (dev->gcBlock < 1 && !aggressive) {
+ dev->gcBlock = yaffs_FindRefreshBlock(dev);
+ dev->gcChunk = 0;
+ }
+ if (dev->gcBlock < 1) {
+ dev->gcBlock = yaffs_FindBlockForGarbageCollection(dev, aggressive, background);
+ dev->gcChunk = 0;
+ }
+
+ if (dev->gcBlock > 0) {
+ dev->allGCs++;
+ if (!aggressive)
+ dev->passiveGCs++;
+
+ T(YAFFS_TRACE_GC,
+ (TSTR
+ ("yaffs: GC erasedBlocks %d aggressive %d" TENDSTR),
+ dev->nErasedBlocks, aggressive));
+
+ gcOk = yaffs_GarbageCollectBlock(dev, dev->gcBlock, aggressive);
+ }
+
+ if (dev->nErasedBlocks < (dev->param.nReservedBlocks) && dev->gcBlock > 0) {
+ T(YAFFS_TRACE_GC,
+ (TSTR
+ ("yaffs: GC !!!no reclaim!!! erasedBlocks %d after try %d block %d"
+ TENDSTR), dev->nErasedBlocks, maxTries, dev->gcBlock));
+ }
+ } while ((dev->nErasedBlocks < dev->param.nReservedBlocks) &&
+ (dev->gcBlock > 0) &&
+ (maxTries < 2));
+
+ return aggressive ? gcOk : YAFFS_OK;
+}
+
+/*
+ * yaffs_BackgroundGarbageCollect()
+ * Garbage collects. Intended to be called from a background thread.
+ * Returns non-zero if at least half the free chunks are erased.
+ */
+int yaffs_BackgroundGarbageCollect(yaffs_Device *dev, unsigned urgency)
+{
+ int erasedChunks = dev->nErasedBlocks * dev->param.nChunksPerBlock;
+
+ T(YAFFS_TRACE_BACKGROUND, (TSTR("Background gc %u" TENDSTR),urgency));
+
+ yaffs_CheckGarbageCollection(dev, 1);
+ return erasedChunks > dev->nFreeChunks/2;
+}
+
+/*------------------------- 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 */