Re: [PATCH v3 2/2] qcow2: Skip copy-on-write when allocating a zero cluster

[Alberto Garcia]

On Fri 11 Sep 2020 11:34:37 AM CEST, Vladimir Sementsov-Ogievskiy wrote:
>> -        if (!is_zero_cow(bs, m)) {
>> +        ret = is_zero_cow(bs, m);
>> +        if (ret < 0) {
>> +            return ret;
>
> It's a common practice to treat block-status errors as "unknown"
> status and not error-out immediately:
>
>   - really, it's not critical, we can continue assuming non-zero
>   - if there are real problems with IO, we'll most probably fail on
>   real read or write operation, and report its status, which seems
>   better for user than block-status error

But what's the problem exactly, does this complicate the code too much?
:-?

> So, I'd keep existing logic in handle_alloc_space(). And, if you agree
> and resend, probably good to split this patch into two, one for
> block.h/io.c and one for qcow2.c (still, I'm OK with it as one patch).

Sure, I can split the patch if I have to resend it.

Berto