From 42fe5af38d0d48a1a3a874c96ee89ecb62f7a4a1 Mon Sep 17 00:00:00 2001
From: Dave Murphy <davem@devkitpro.org>
Date: Mon, 31 Jul 2017 14:45:57 +0100
Subject: [PATCH] update FAT32 FSINFO for statvfs if invalid

---
 source/fatdir.c    | 13 +++++--------
 source/partition.c | 17 ++++++++++++-----
 2 files changed, 17 insertions(+), 13 deletions(-)

diff --git a/source/fatdir.c b/source/fatdir.c
index 4c3aaca..1ef5aec 100644
--- a/source/fatdir.c
+++ b/source/fatdir.c
@@ -465,16 +465,13 @@ int _FAT_statvfs_r (struct _reent *r, const char *path, struct statvfs *buf)
 
 	_FAT_lock(&partition->lock);
 
-	if(memcmp(&buf->f_flag, "SCAN", 4) == 0)
-	{
-		//Special command was given to sync the numberFreeCluster
-		_FAT_partition_createFSinfo(partition);
-	}
-
-	if(partition->filesysType == FS_FAT32)
+	if(partition->filesysType == FS_FAT32) {
+		// Sync FSinfo block
+		_FAT_partition_readFSinfo(partition);
 		freeClusterCount = partition->fat.numberFreeCluster;
-	else
+	} else {
 		freeClusterCount = _FAT_fat_freeClusterCount (partition);
+	}
 
 	// FAT clusters = POSIX blocks
 	buf->f_bsize = partition->bytesPerCluster;		// File system block size.
diff --git a/source/partition.c b/source/partition.c
index 108776a..1584e0e 100644
--- a/source/partition.c
+++ b/source/partition.c
@@ -348,6 +348,13 @@ PARTITION* _FAT_partition_getPartitionFromPath (const char* path) {
 	return (PARTITION*)devops->deviceData;
 }
 
+static void _FAT_updateFS_INFO(PARTITION * partition, uint8_t *sectorBuffer) {
+	partition->fat.numberFreeCluster = _FAT_fat_freeClusterCount(partition);
+	u32_to_u8array(sectorBuffer, FSIB_numberOfFreeCluster, partition->fat.numberFreeCluster);
+	u32_to_u8array(sectorBuffer, FSIB_numberLastAllocCluster, partition->fat.numberLastAllocCluster);
+	_FAT_disc_writeSectors (partition->disc, partition->fsInfoSector, 1, sectorBuffer);
+}
+
 void _FAT_partition_createFSinfo(PARTITION * partition)
 {
 	if(partition->readOnly || partition->filesysType != FS_FAT32)
@@ -364,14 +371,10 @@ void _FAT_partition_createFSinfo(PARTITION * partition)
 		sectorBuffer[FSIB_SIG2+i] = FS_INFO_SIG2[i];
 	}
 
-	partition->fat.numberFreeCluster = _FAT_fat_freeClusterCount(partition);
-	u32_to_u8array(sectorBuffer, FSIB_numberOfFreeCluster, partition->fat.numberFreeCluster);
-	u32_to_u8array(sectorBuffer, FSIB_numberLastAllocCluster, partition->fat.numberLastAllocCluster);
-
 	sectorBuffer[FSIB_bootSig_55] = 0x55;
 	sectorBuffer[FSIB_bootSig_AA] = 0xAA;
 
-	_FAT_disc_writeSectors (partition->disc, partition->fsInfoSector, 1, sectorBuffer);
+	_FAT_updateFS_INFO(partition,sectorBuffer);
 
 	_FAT_mem_free(sectorBuffer);
 }
@@ -398,6 +401,10 @@ void _FAT_partition_readFSinfo(PARTITION * partition)
 		_FAT_partition_createFSinfo(partition);
 	} else {
 		partition->fat.numberFreeCluster = u8array_to_u32(sectorBuffer, FSIB_numberOfFreeCluster);
+		if(partition->fat.numberFreeCluster == 0xffffffff) {
+			_FAT_updateFS_INFO(partition,sectorBuffer);
+			partition->fat.numberFreeCluster = u8array_to_u32(sectorBuffer, FSIB_numberOfFreeCluster);
+		}
 		partition->fat.numberLastAllocCluster = u8array_to_u32(sectorBuffer, FSIB_numberLastAllocCluster);
 	}
 	_FAT_mem_free(sectorBuffer);