[PATCH] volume_id: volume_id_get_buffer with small FSes

[Lauri Kasanen]

On Mon, 16 May 2022 10:03:20 +0000
Alyssa Ross <hi at alyssa.is> wrote:

> On Mon, May 16, 2022 at 08:23:37AM +0300, Lauri Kasanen wrote:
> > On Sun, 15 May 2022 17:18:47 +0000
> > Alyssa Ross <hi at alyssa.is> wrote:
> >
> > > I tested both the cases mentioned in the comments — an empty floppy
> > > drive, and an unused loop device.  Reading from an empty floppy drive
> > > is ENXIO, and reading from an unused loop device returns 0, so it
> > > should be fine to drop the minimum length, and be happy with any read
> > > as long as it returns at least one byte.
> >
> > > -		 * accesses. Rationale:
> > > -		 * users complained of slow blkid due to empty floppy drives.
> >
> > But is it slow like the comment said? Ie. does this patch cause a 1-2s
> > delay due to the floppy drive spinning up?
>
> How would it?  In the case of a floppy or loop device, the operations
> that are happening are exactly the same.  Both before and after my
> patch, it would try to seek or read, that would fail, and then it would
> set id->error and return.

If you mean that the code comment was wrong, please mention that in
the commit message.

- Lauri