Re: Large volume ll_ver_fs results (w/ short read/write patch).

[Nick Dokos <nicholas.dokos@hp.com>]

> Nick, thanks for the patch.  I'm incorporating the fixes upstream,
> but one question that was raised is that (in essence) this allows
> IO errors to be hit, yet and the return code from llverfs is 0.
> The llverdev/llverfs tools are used not only for finding software
> data corruption bugs, but also to verify the underlying media.
> 
> It was definitely a bug in the original code that there was no
> error reported during the write phase if there was a short write,
> but this was at least caught during the read phase because the
> data would be incorrect.
> 
> What I've done is to count errors hit during read and write, and
> then exit with a non-zero value if there were any IO errors hit
> (as happened in your case), even if the rest of the data was
> verified correctly.  This allows scanning the whole disk in a
> single pass (if there are not too many underlying errors) but
> still ensuring there is no false sense of security because the
> program exited with 0.
> 
> The current patch can be gotten at:
> 
> https://bugzilla.lustre.org/attachment.cgi?id=25407&action=edit
> 

Thanks! It looks good at first glance: I'll be trying it out before
long and will let you know if I come up against any problems.

Nick