Subject: Re: bug#21522: assertion metadata_length > 0 in add_logical_part_metadata failed

From: "Brian C. Lane" <[email-masked]>
Date: Thu, 24 Sep 2015 08:56:33 -0700

On Thu, Sep 24, 2015 at 10:53:31AM -0400, Phil Susi wrote:
> On 9/23/2015 8:15 PM, Brian C. Lane wrote:
> > This isn't actually a bug, logical partitions need to have at least 1
> > sector between them for metadata storage. parted enforces this when
> > creating logical partitions, but other tools do not.
> 
> While parted lays out the disk this way, it doesn't have to be.  The EBR
> for each chained logical volume can be placed anywhere in the extended
> partition.  In his case, it looks like both are at the start of the
> extended partition.  This is perfectly ok and parted should accept it.
> 
> Now that I have both EBRs I'm able to reproduce the crash and will try
> to fix it.

Are you sure? According to
https://en.wikipedia.org/wiki/Extended_boot_record the EBR is at the
start of each logical partition, and chains to the next. I suppose it is
possible that would work since it has separate pointers for the
partition and the next EBR but none of the authoritative diagrams I've
seen show that. eg.
https://technet.microsoft.com/en-us/library/cc977219.aspx also shows the
EBR at the start of the logical partition.

-- 
Brian C. Lane | Anaconda Team | IRC: bcl #anaconda | Port Orchard, WA (PST8PDT)