+
+/*
+ * Oldest Dirty Sequence Number handling.
+ */
+
+/* yaffs_CalcOldestDirtySequence()
+ * yaffs_FindOldestDirtySequence()
+ * Calculate the oldest dirty sequence number if we don't know it.
+ */
+static int yaffs_CalcOldestDirtySequence(yaffs_Device *dev)
+{
+ int i;
+ __u32 seq;
+ yaffs_BlockInfo *b = 0;
+
+
+ /* Find the oldest dirty sequence number. */
+ 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->param.nChunksPerBlock &&
+ b->sequenceNumber < seq)
+ seq = b->sequenceNumber;
+ }
+ return seq;
+}
+
+
+static void yaffs_FindOldestDirtySequence(yaffs_Device *dev)
+{
+ if(!dev->oldestDirtySequence)
+ dev->oldestDirtySequence =
+ yaffs_CalcOldestDirtySequence(dev);
+
+#if 0
+ if(!yaffs_SkipVerification(dev) &&
+ dev->oldestDirtySequence != yaffs_CalcOldestDirtySequence(dev))
+ YBUG();
+
+#endif
+}
+
+/*
+ * yaffs_ClearOldestDirtySequence()
+ * Called when a block is erased or marked bad. (ie. when its sequenceNumber
+ * becomes invalid). If the value matches the oldest then we clear
+ * dev->oldestDirtySequence to force its recomputation.
+ */
+static void yaffs_ClearOldestDirtySequence(yaffs_Device *dev, yaffs_BlockInfo *bi)
+{
+
+ if(!bi || bi->sequenceNumber == dev->oldestDirtySequence)
+ dev->oldestDirtySequence = 0;
+}
+
+/*
+ * yaffs_UpdateOldestDirtySequence()
+ * Update the oldest dirty sequence number whenever we dirty a block.
+ * Only do this if the oldestDirtySequence is actually being tracked.
+ */
+static void yaffs_UpdateOldestDirtySequence(yaffs_Device *dev, yaffs_BlockInfo *bi)
+{
+ if(dev->oldestDirtySequence){
+ if(dev->oldestDirtySequence > bi->sequenceNumber)
+ dev->oldestDirtySequence = bi->sequenceNumber;
+ }
+}
+