[parted-devel] [PATCH 1/2] libparted: enforce dos partition limit

Jim Meyering jim at meyering.net
Wed Jan 18 13:52:15 UTC 2012


Vladimir 'φ-coder/phcoder' Serbinenko wrote:
>> The msdos partition table claimed a maximum partition count of 16 but
> would allow you to go beyond that. This resulted in the kernel not
>> being informed of
>> those partitions. Corrected to enforce the limit.
> I disagree with this patch being good. msdos layout has no inherent
> limit on number of logical partitions. The above mentioned limit comes
> from how Linux allocates minor SCSI bits and presence of this limit is
> Linux bug. non-SCSI disks on Linux have higher limit. Even on SCSI
> disks it can be circumvented with kpartx. Moreover other kernels and
> tools are probably not affected by this limit.
> If you really want to handle this limit AFAIK it's not specific to
> just msdos partitions, so it has to be on higher level and happen only
> on SCSI disks and only when running under Linux or similarly affected
> kernels (e.g. kOpenSolaris has a similar limit) and has to be reduced
> to a warning since a bug in some other software isn't a reason to
> create a same bug.

Hi Vladimir,

Thanks for the clarification that there is no inherent limit.
IMHO, the patch is an improvement, though, don't you think?
The previous limit was 16.  Now it's 64.

I'd be more inclined to worry about this arbitrary limitation
if I knew parted were being built on any non-Linux system, or
if there were bug reports of people trying to use parted to
create 65 or more partitions with an msdos partition table
on a system for which that is possible.



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