Re: 2.6.28 /proc/diskstats

[Tejun Heo]

Daniel Collins wrote:
> Hi
> 
> Since 2.6.28, fd0 isn't visible in /proc/diskstats from boot, only after
> access/mount. It is visible in /sys/block/ from boot, so there are no
> issues detecting it. This may also affect other devices such as hda but
> I haven't tested this yet, my test system and QEMU both only have
> ram0-ram15 from boot. I have tested 2.6.30-rc1 and found the same
> behavior. Is this a bug or a deliberate change?

Hmm... the reason why fd device is skipped before the first open is
because diskstats_show() skips zero sized devices and open is when the
floppy driver sets the capacity.  I think the original code also
skipped zero sized device.  It could be that the original code
triggered revalidation while the current one doesn't.  I'll dig
deeper.

Thanks.

-- 
tejun
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