[PATCH] FAT: Fix ->prev_free of fat (6/10)

From: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>

The -1 was documented as "there is no hint", so this patch uses -1 instead
of 0 for FAT32 fsinfo.

fs/fat/inode.c

@@ -885,7 +885,7 @@ int fat_fill_super(struct super_block *sb, void *data, int silent,
 	sbi->fat_length = CF_LE_W(b->fat_length);
 	sbi->root_cluster = 0;
 	sbi->free_clusters = -1;	/* Don't know yet */
-	sbi->prev_free = 0;
+	sbi->prev_free = -1;
 
 	if (!sbi->fat_length && b->fat32_length) {
 		struct fat_boot_fsinfo *fsinfo;

fs/fat/misc.c

@@ -74,7 +74,7 @@ void fat_clusters_flush(struct super_block *sb)
 	} else {
 		if (sbi->free_clusters != -1)
 			fsinfo->free_clusters = CF_LE_L(sbi->free_clusters);
-		if (sbi->prev_free)
+		if (sbi->prev_free != -1)
 			fsinfo->next_cluster = CF_LE_L(sbi->prev_free);
 		mark_buffer_dirty(bh);
 	}

include/linux/msdos_fs_sb.h

@@ -49,7 +49,7 @@ struct msdos_sb_info {
 	unsigned long root_cluster;  /* first cluster of the root directory */
 	unsigned long fsinfo_sector; /* FAT32 fsinfo offset from start of disk */
 	struct semaphore fat_lock;
-	int prev_free;               /* previously returned free cluster number */
+	int prev_free;               /* previously allocated cluster number */
 	int free_clusters;           /* -1 if undefined */
 	struct fat_mount_options options;
 	struct nls_table *nls_disk;  /* Codepage used on disk */