On 3/21/2012 10:00 PM, John Gilmore wrote:
I don't think this patch is quite right. The exception should be fixed rather
than removed. If it is supposed to be a GPT disk, then we should fix the
broken PMBR. If it is not, then we should zap the GPT and then fail to
recognize the disk as GPT ( thus allowing it to be recognized as DOS ).
At startup, Parted should not be "zapping" anybody's disk drive, no
matter how invalid it looks. The drive should remain read-only until
if-and-when the user explicitly commands parted to write something.
Occasionally, in the distant past, I have had to write zeroes over the
first blocks of a disk (using "dd") in order to get parted to let me
relabel it without getting confused by its prior contents. Perhaps
parted should have a "zap" command that allows some area(s) of the
drive to be zeroed without using a separate program. Then Parted could
produce a diagnostic message when it detects this kind of mangled GPT,
suggesting that the *user* "zap" the drive.
That's exactly what I'm talking about. The exception was already in
place to ask the user whether it is supposed to be gpt or not. The
missing part was the corrective action based on their response. If it's
supposed to be gpt, then fix the pmbr, if not, then zap the invalid gpt,
and of course, do neither if unhandled. Actually, I suppose it could be
broken into two parts: the yes/no to recognize it as gpt or not, and
then a second exception asking to ignore or fix the error. That way you
could choose to look at the disk one way, and then the other to help
decide which is the correct table before taking corrective action.
