Re: [Libguestfs] [PATCH libnbd v3 2/3] copy: Use preferred block size for copying

On Thu, Jun 30, 2022 at 05:38:14PM +0200, Laszlo Ersek wrote: >> +static bool >> +only_zeroes (const extent_list exts, size_t *i, [...] >> + >> + if (start >= offset + len) >> + break; >> + > > (13) I think we can insert a micro-optimization here: > > *i = j; [...] > The loop at the start of the function is correct, but here we can save > some work for its next execution (in the next invocation of this function). Just a note that I didn't do this optimization. The reason is that it breaks the ability (which we don't use) of calling only_zeroes twice on the same offset. I just feel that it might cause unexpected results if someone hoisted out the only_zeroes call into a debug printf or similar. I made the rest of the suggested changes, except for splitting out the test into another commit - we surely want to keep the test with the change that is being tested.