Re: [RFC] fallocate utility

[Pádraig Brady]

Eric Sandeen wrote:
> Pádraig Brady wrote:
>> Eric Sandeen wrote:
> 
>>> TBH I think "truncate --allocate" sounds a little odd.  (Now that I
>>> think back, I think I mentioned this before).  truncate(1) and
>>> truncate(2) specifically refer to i_size, which to fs people like me,
>>> has nothing to do with the actual blocks allocated to a file.
>> Well truncate(2) does, but I think truncate(1) is higher level
>> and is used to "set the size of a file". 
> 
> But "size of a file" in the truncate sense only means "set the EOF offset."

I don't see a problem in extending the meaning of the truncate command.
Now truncate isn't the best name for the command but that name
already existed in BSD and so I thought it best to align with that.
So what about also having an fallocate command in coreutils?
Well it would benefit from all the existing options of the truncate command,
I.E. would share most of the code, so I'm not convinced.

> I guess I don't -really- care if "truncate" grows an "--allocate"
> option, but I'd still like to see a nice "fallocate" in util-linux-ng ;)

A reason to have this functionality in coreutils is that the core
functionality of posix_fallocate() is not linux specific.
Also fallocate() like functionality is exposed on solaris
for example through fcntl(fd, F_ALLOCSP, ...).

BTW I think your fallocate util might benefit from
calling truncate(2) to allow one to shrink files also?

cheers,
Pádraig.