[COMMON] some patches from yaffs pubic git, cleaneye.kim@lge.com

	- hopes that these patches mitigate yaffs crash when mount time

Signed-off-by: cleaneye <cleaneye.kim@lge.com>

fs/yaffs2/yaffs_fs.c

@@ -2014,22 +2014,27 @@ static struct super_block *yaffs_internal_read_super(int yaffsVersion,
 	int err;
 	char *data_str = (char *)data;
 
+	int readOnly = 0;
+
 	yaffs_options options;
 
 	sb->s_magic = YAFFS_MAGIC;
 	sb->s_op = &yaffs_super_ops;
 	sb->s_flags |= MS_NOATIME;
 
+	readOnly = ((sb->s_flags & MS_RDONLY) != 0);
+
 	if (!sb)
 		printk(KERN_INFO "yaffs: sb is NULL\n");
 	else if (!sb->s_dev)
 		printk(KERN_INFO "yaffs: sb->s_dev is NULL\n");
 	else if (!yaffs_devname(sb, devname_buf))
 		printk(KERN_INFO "yaffs: devname is NULL\n");
 	else
-		printk(KERN_INFO "yaffs: dev is %d name is \"%s\"\n",
+		printk(KERN_INFO "yaffs: dev is %d name is \"%s\" %s\n",
 		       sb->s_dev,
-		       yaffs_devname(sb, devname_buf));
+		       yaffs_devname(sb, devname_buf),
+			   readOnly ? "ro" : "rw");
 
 	if (!data_str)
 		data_str = "";
@@ -2176,6 +2181,12 @@ static struct super_block *yaffs_internal_read_super(int yaffsVersion,
 	 * Set the yaffs_Device up for mtd
 	 */
 
+	if (!readOnly && !(mtd->flags & MTD_WRITEABLE)) {
+		readOnly = 1;
+		printk(KERN_INFO, "yaffs: mtd is read only, setting superblock read only\n");
+		sb->s_flags |= MS_RDONLY;
+	}
+
 #if (LINUX_VERSION_CODE > KERNEL_VERSION(2, 5, 0))
 	sb->s_fs_info = dev = kmalloc(sizeof(yaffs_Device), GFP_KERNEL);
 #else
@@ -2250,6 +2261,7 @@ static struct super_block *yaffs_internal_read_super(int yaffsVersion,
 	dev->superBlock = (void *)sb;
 	dev->markSuperBlockDirty = yaffs_MarkSuperBlockDirty;
 
+	dev->readOnly = readOnly;
 
 #ifndef CONFIG_YAFFS_DOES_ECC
 	dev->useNANDECC = 1;

fs/yaffs2/yaffs_guts.c

@@ -35,6 +35,14 @@ const char *yaffs_guts_c_version =
 
 #define YAFFS_PASSIVE_GC_CHUNKS 2
 
+/* 
+ * 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"
 
 
@@ -2835,12 +2843,20 @@ static int yaffs_FindBlockForAllocation(yaffs_Device *dev)
 	return -1;
 }
 
+static int yaffs_CheckpointRequired(yaffs_Device *dev)
+{
+	int nblocks = dev->internalEndBlock - dev->internalStartBlock + 1;
 
+	return dev->isYaffs2 &&
+			!dev->skipCheckpointWrite &&
+			(nblocks >= YAFFS_CHECKPOINT_MIN_BLOCKS);
+}
 
 static int yaffs_CalcCheckpointBlocksRequired(yaffs_Device *dev)
 {
 	if (!dev->nCheckpointBlocksRequired &&
-	   dev->isYaffs2) {
+//	   dev->isYaffs2) {
+		yaffs_CheckpointRequired(dev)) {
 		/* Not a valid value so recalculate */
 		int nBytes = 0;
 		int nBlocks;
@@ -4534,7 +4550,8 @@ static int yaffs_WriteCheckpointData(yaffs_Device *dev)
 {
 	int ok = 1;
 
-	if (dev->skipCheckpointWrite || !dev->isYaffs2) {
+//	if (dev->skipCheckpointWrite || !dev->isYaffs2) {
+	if (!yaffs_CheckpointRequired(dev)) {
 		T(YAFFS_TRACE_CHECKPOINT, (TSTR("skipping checkpoint write" TENDSTR)));
 		ok = 0;
 	}
@@ -5167,7 +5184,8 @@ static int yaffs_UnlinkFileIfNeeded(yaffs_Object *in)
 int yaffs_DeleteFile(yaffs_Object *in)
 {
 	int retVal = YAFFS_OK;
-	int deleted = in->deleted;
+	//int deleted = in->deleted;
+	int deleted; /* Need to cache value on stack if in is freed */
 
 	yaffs_ResizeFile(in, 0);
 
@@ -5178,6 +5196,8 @@ int yaffs_DeleteFile(yaffs_Object *in)
 		if (!in->unlinked)
 			retVal = yaffs_UnlinkFileIfNeeded(in);
 
+		deleted = in->deleted;
+
 		if (retVal == YAFFS_OK && in->unlinked && !in->deleted) {
 			in->deleted = 1;
 			deleted = 1;
@@ -5451,6 +5471,9 @@ static void yaffs_StripDeletedObjects(yaffs_Device *dev)
 	struct ylist_head *n;
 	yaffs_Object *l;
 
+	if (dev->readOnly)
+		return;
+
 	/* Soft delete all the unlinked files */
 	ylist_for_each_safe(i, n,
 		&dev->unlinkedDir->variant.directoryVariant.children) {
@@ -5504,6 +5527,9 @@ static void yaffs_FixHangingObjects(yaffs_Device *dev)
 	int depthLimit;
 	int hanging;
 
+	if (dev->readOnly)
+		return;
+
 
 	/* Iterate through the objects in each hash entry,
 	 * looking at each object.
@@ -6338,6 +6364,15 @@ static int yaffs_ScanBackwards(yaffs_Device *dev)
 
 				  dev->nFreeChunks++;
 
+			} else if (tags.objectId > YAFFS_MAX_OBJECT_ID ||
+				tags.chunkId > YAFFS_MAX_CHUNK_ID ||
+				(tags.chunkId > 0 && tags.byteCount > dev->nDataBytesPerChunk)) {
+				T(YAFFS_TRACE_SCAN,
+				 (TSTR("Chunk (%d:%d) with bad tags:obj = %d, chunkId = %d, byteCount = %d, ignored"TENDSTR),
+			  	 blk, c, tags.objectId, tags.chunkId, tags.byteCount));
+
+				  dev->nFreeChunks++;			
+
 			} else if (tags.chunkId > 0) {
 				/* chunkId > 0 so it is a data chunk... */
 				unsigned int endpos;

fs/yaffs2/yaffs_guts.h

@@ -63,6 +63,8 @@
 
 #define YAFFS_OBJECT_SPACE		0x40000
 
+#define YAFFS_MAX_OBJECT_ID		(YAFFS_OBJECT_SPACE - 1)
+
 #define YAFFS_CHECKPOINT_VERSION 	3
 
 #ifdef CONFIG_YAFFS_UNICODE
@@ -648,6 +650,7 @@ struct yaffs_DeviceStruct {
 #endif
 
 	int isMounted;
+	int readOnly;
 
 	int isCheckpointed;
 

fs/yaffs2/yportenv.h

@@ -73,6 +73,7 @@
 
 /* KR - added for use in scan so processes aren't blocked indefinitely. */
 #define YYIELD() schedule()
+#define Y_DUMP_STACK() dump_stack()
 
 #define YAFFS_ROOT_MODE			0666
 #define YAFFS_LOSTNFOUND_MODE		0666
@@ -196,8 +197,17 @@ extern unsigned int yaffs_wr_attempts;
 
 #define T(mask, p) do { if ((mask) & (yaffs_traceMask | YAFFS_TRACE_ALWAYS)) TOUT(p); } while (0)
 
+#ifndef Y_DUMP_STACK
+#define Y_DUMP_STACK() do { } while(0)
+#endif
+
 #ifndef YBUG
-#define YBUG() do {T(YAFFS_TRACE_BUG, (TSTR("==>> yaffs bug: " __FILE__ " %d" TENDSTR), __LINE__)); } while (0)
+#define YBUG() do {\
+		T(YAFFS_TRACE_BUG, \
+				(TSTR("==>> yaffs bug: " __FILE__ " %d" TENDSTR),\
+				 __LINE__));\
+		Y_DUMP_STACK();\
+} while (0)
 #endif
 
 #endif