"gpart add" falsely claiming "No space left on device"

William A. Mahaffey III wam at hiwaay.net
Fri Sep 9 13:11:26 UTC 2016


On 09/09/16 03:53, Perry Hutchison wrote:
> "Brandon J. Wandersee" <brandon.wandersee at gmail.com> wrote:
>> Perry Hutchison writes:
>>> Warren Block <wblock at wonkity.com> wrote:
>>>> What does the man page need?
>>> For starters, default values for -b, -s, -t, and -i in "gpart add".
>>> (I guess -i defaults to "lowest not currently in use", but what about
>>> the others?)
>> The defaults are exactly what you'd expect them to be. '-b' defaults
>> to the start of the disk.
> That would explain why my first attempt failed, since that default
> is useful only if no partitions are already defined.
>
> Other reasonable defaults would be the start of the first (lowest
> addressed), last (highest addressed), or largest free area.  In any
> event, the man page ought to say what the default is.
>
>> '-i' defaults to the lowest available integer.
> as I suspected
>
>> '-s' defaults to everything available.
> "available" on the entire disk (as if no partitions were defined),
> the first free block, or the largest free block?  (One hopes, not
> the sum of all free blocks :)  Again, the man page should say!
>
>> '-t' default to nothing,
>> because it would be senseless to assume the type of a partition;
>> gpart(8) will exit with an error if you don't provide it.
> ... which _could_ be implied by its not being bracketed in the usage
> section, if not for the fact that -b and -s (which apparently do
> have defaults, even though the man page does not say what they are)
> are not bracketed either.
>
>>> List of what-all "attributes" can be set and what they do.
>> See "ATTRIBUTES."
> There's no such section in the gpart(8) man page I'm looking at (on
> FreeBSD 8.1).

Aaaaaaahhhhhh :-). Look at the online man pages, either on FreeBSD site 
if they are there (I don't know) or type 'man gpart' in your search bar 
& it will turn some up ....

>
>>> Explanation of when one would use -b vs. -p in "gpart bootcode"
>>> since they are apparently different ways of specifying where the
>>> bootcode comes from (but then your example uses both?)
>> '-b' and '-p' specify different values. '-b' specifies what is written;
>> '-p' specifies how and where. How they're used depends on your partition
>> scheme and motherboard. See "BOOTSTRAPPING."
> There's no BOOTSTRAPPING section in this gpart(8) man page, either.
>
>>> Description of how to show the current state of the provider vs what
>>> it would look like if pending changes were committed.
>> I don't know if this is possible. I believe it's assumed that the
>> user/administrator has---or at least *should* have---a good idea
>> of what state the disk is in before they start messing with the
>> existing (presumably good) partition table.
> Seems to me it kind of defeats the purpose of "pending" changes, if
> I can't say "show me what would change if I committed this set" --
> the same general idea as doing
>    :w !diff % -
> in vi before saving the file.
>
>>> I suppose there must be some reason for leaving those
>>> 3.0k and 492k free spaces around gpboot, but it isn't obvious.
>> Partition alignment.
> Alignment to 4k makes sense if the physical sector size is 4k (as
> is often the case with newer disk drives) -- but 1M?  Seems a bit
> much, which is why it would be useful for that page to include a
> more detailed explanation.
>
> Getting back to the original inquiry, I'm still mystified as to
> why gpart won't create a partition in the space that it reports
> as being free.  Does anyone have a clue what is going on, or how
> to find out?
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See above ....

-- 

	William A. Mahaffey III

  ----------------------------------------------------------------------

	"The M1 Garand is without doubt the finest implement of war
	 ever devised by man."
                            -- Gen. George S. Patton Jr.



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