yaffs: Don't do checkpoint for small partitions.

[yaffs2.git] / yaffs_guts.c

diff --git a/yaffs_guts.c b/yaffs_guts.c
index 087ac958f61f127a9c9d8c99a89d1b5e71d70fb5..d067d1d03d53552efbff6d9bd16e84f83a86f71d 100644 (file)
--- a/yaffs_guts.c
+++ b/yaffs_guts.c
@@ -1,7 +1,7 @@
 /*
  * YAFFS: Yet Another Flash File System. A NAND-flash specific file system.
  *
- * Copyright (C) 2002-2007 Aleph One Ltd.
+ * Copyright (C) 2002-2010 Aleph One Ltd.
  *   for Toby Churchill Ltd and Brightstar Engineering
  *
  * Created by Charles Manning <charles@aleph1.co.uk>
@@ -10,10 +10,6 @@
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  */
-
-const char *yaffs_guts_c_version =
-    "$Id: yaffs_guts.c,v 1.120 2010-03-15 23:10:34 charles Exp $";
-
 #include "yportenv.h"
 #include "yaffs_trace.h"
 
@@ -37,8 +33,17 @@ const char *yaffs_guts_c_version =
 /* Note YAFFS_GC_GOOD_ENOUGH must be <= YAFFS_GC_PASSIVE_THRESHOLD */
 #define YAFFS_GC_GOOD_ENOUGH 2
 #define YAFFS_GC_PASSIVE_THRESHOLD 4
+
 #define YAFFS_SMALL_HOLE_THRESHOLD 3
 
+/*
+ * Checkpoints are really no benefit on very small partitions.
+ *
+ * To save space on small partitions don't bother with checkpoints unless
+ * the partition is at least this big.
+ */
+#define YAFFS_CHECKPOINT_MIN_BLOCKS 60
+
 #include "yaffs_ecc.h"
 
 
@@ -183,7 +188,7 @@ static __u32 ShiftsGE(__u32 x)
 
 static __u32 Shifts(__u32 x)
 {
-       int nShifts;
+       __u32 nShifts;
 
        nShifts =  0;
 
@@ -2956,10 +2961,17 @@ static int yaffs_FindBlockForAllocation(yaffs_Device *dev)
 
 
 
+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 &&
-          dev->param.isYaffs2) {
+               yaffs_CheckpointRequired(dev)){
                /* Not a valid value so recalculate */
                int nBytes = 0;
                int nBlocks;
@@ -4880,7 +4892,7 @@ static int yaffs_WriteCheckpointData(yaffs_Device *dev)
 {
        int ok = 1;
 
-       if (dev->param.skipCheckpointWrite || !dev->param.isYaffs2) {
+       if (!yaffs_CheckpointRequired(dev)) {
                T(YAFFS_TRACE_CHECKPOINT, (TSTR("skipping checkpoint write" TENDSTR)));
                ok = 0;
        }
@@ -5136,8 +5148,6 @@ int yaffs_DoWriteDataToFile(yaffs_Object *in, const __u8 *buffer, loff_t offset,
        dev = in->myDev;
 
        while (n > 0 && chunkWritten >= 0) {
-               /* chunk = offset / dev->nDataBytesPerChunk + 1; */
-               /* start = offset % dev->nDataBytesPerChunk; */
                yaffs_AddrToChunk(dev, offset, &chunk, &start);
 
                if (chunk * dev->nDataBytesPerChunk + start != offset ||
@@ -5147,7 +5157,7 @@ int yaffs_DoWriteDataToFile(yaffs_Object *in, const __u8 *buffer, loff_t offset,
                           TENDSTR),
                           (int)offset, chunk, start));
                }
-               chunk++;
+               chunk++; /* File pos to chunk in file offset */
 
                /* OK now check for the curveball where the start and end are in
                 * the same chunk.