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Re: [Qemu-devel] Re: [PATCH] block: fix sector comparism in multiwrite_r
Re: [Qemu-devel] Re: [PATCH] block: fix sector comparism in multiwrite_req_compare
Thu, 20 May 2010 09:09:12 +0300
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On 05/20/2010 12:09 AM, Kevin Wolf wrote:
Actually it's not that obvious. If the actual problem
here (besides the mis-comparison) is due to missing
barriers or flushes. Avi asked a good question in that
It's obvious that it's a hack. It doesn't fix anything, it just disables a
feature that didn't work. Good for debugging, but not something that you
would like to commit.
It's reasonable to include something like this when we know that something is
broken but we haven't found it yet - but I believe Christoph's patch is the
real fix. If anyone can still find a case that is "fixed" by Avi's patch, I
could be convinced to apply it anyway, but I'd prefer if I didn't have to.
Note that we actually don't have overlapping requests. It just looks like it
because the qsort call doesn't work correctly with the broken comparison
function, so lower sector numbers can come after higher ones.
I agree my patch didn't fix the problem, only made it disappear, but
won't the current code break with overlapping requests?
Do not meddle in the internals of kernels, for they are subtle and quick to
[Qemu-devel] Re: [PATCH] block: fix sector comparism in multiwrite_req_compare, Kevin Wolf, 2010/05/20