bug#11100: Racy code in copy.c

[Jim Meyering]

Eric Blake wrote:
> On 05/04/2012 08:47 AM, Jim Meyering wrote:
>>
>> * src/copy.c (copy_reg): In a narrow race (stat sees dest, yet
>> open-without-O_CREAT fails with ENOENT), retry the open with O_CREAT.
>> Reported by Philipp Thomas and Neil F. Brown in
>> http://debbugs.gnu.org/11100
>
> Question - when we retry with adding O_CREAT, should we also add O_EXCL?
>  That is, we already lost the race once, but the O_EXCL will ensure that
> we don't lose the race a second time and that we really are creating a file.

And thanks for looking.