[PATCH] common: filetype: do not redetect MBR-type devices as a FAT-type

[Trent Piepho]

On Mon, 2015-11-09 at 13:32 +0300, Peter Mamonov wrote:
> Deleted pieces of code detect MBR-containig device as a FAT-type device,
> if it's first partition contains a FAT filesystem. This behaviour enabled one
> to mount the FAT FS which is either directly on the device (disk0) or on
> the first partition (disk0.0) using the same command:
>     mount /dev/disk0 /fat
> However, the desired behaviour can be reached with a:
>     mount /dev/disk0 /fat || mount /dev/disk0.0 /fat || echo "Mounting failed"

The in flash env for omap is found by mounting a FAT filesystem and
reading an env file from it.  The code that does this uses the disk as
the device, rather than the partition.  Which I thought was odd and
wondered why/if that worked correctly....

Anyway, this change would break that code.  I suspect than instead of
coding the disk0 || disk0.0 method it could just mount disk0.0.  Because
the code does this (edited):

partname = asprintf("/dev/%s.0", diskdev);
ret = stat(partname, &s);
if (ret) {
  pr_err("Failed to load environment: no device '%s'\n", diskdev);
  return 0;
}
ret = mount(diskdev, "fat", "/boot", NULL);


If disk0.0 didn't exist then it wouldn't try to mount it in the 1st
place, so the ability of trying both disk0 and disk0.0 wouldn't be used.