fat32.Filesystem fails silently when writing files to a directory with many items

[RafaelMarinheiro]

I'm trying to write a program that formats an SD card and writes the contents of https://github.com/raspberrypi/firmware/tree/master/boot/ to it. The core of the code is:

	d, _ := diskfs.Open(dev)
	sectorSize := 512
	ptable := &mbr.Table{
		LogicalSectorSize:  sectorSize,
		PhysicalSectorSize: sectorSize,
		Partitions: []*mbr.Partition{
			{
				Type:  mbr.Fat32LBA,
				Start: 4 * MiB / uint32(sectorSize),
				Size:  2 * GiB / uint32(sectorSize),
			},
		},
	}
	_ := d.Partition(ptable)
	fs, _ := d.CreateFilesystem(disk.FilesystemSpec{
		Partition: 1, FSType: filesystem.TypeFat32, 
	})
	for _, file := range files {
		dest, _ := fs.OpenFile(...)
		_, _ = dest.Write(file.data)
	}

Error handling has been abbreviated as well as directory creation, but both are there in my code.

Once I try to write the files in https://github.com/raspberrypi/firmware/tree/master/boot/overlays (219 entries) to /overlays the code does not report any errors, however only the first ~50-ish files are properly written. Files that are supposedly written later, but to a different directory, are still written correctly.

IMHO this is particularly bad because both fs.OpenFile and dest.Write fail silently, so the caller/user will just notice this much after the program has executed.

[deitch]

Do they not report errors? The above code ignores the errors:

		dest, _ := fs.OpenFile(...)
		_, _ = dest.Write(file.data)

Is there a way to reproduce the problem without an SD card? It would be great to have a standalone program that reproduces it.

[deitch]

Now that #110 is in, can we see if we can reproduce this?