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From:   Junio C Hamano <gitster@pobox.com>
To:     Elijah Newren <newren@gmail.com>
Cc:     Phillip Wood <phillip.wood@dunelm.org.uk>,
        Git Mailing List <git@vger.kernel.org>
Subject: Re: BUG: fast-import, ftruncate, and file mode
References: <CABPp-BERVCynOVvBq0QL49Ah+gy3W2snUVWBHfzXaVpXX3Dpyg@mail.gmail.com>
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Date:   Wed, 23 Feb 2022 15:18:17 -0800
In-Reply-To: <CABPp-BF_ygATPVGfSR24URm5ZTHBJwJd0miMtgMgNWfw_o33Nw@mail.gmail.com>
        (Elijah Newren's message of "Wed, 23 Feb 2022 07:33:29 -0800")
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Elijah Newren <newren@gmail.com> writes:

>> Am I missing something or is this really a file system bug? Surely if we
>> have opened a file for writing the file permissions when we call
>> ftruncate() should be irrelevant?
>> ...
> Oh, indeed, looks like I can't read late at night.  Sorry for the noise.

Was wondering the same thing.

We open for writing, write one object at a time and when we realize
we do not have to, we rewind that stream we are writing into using
ftruncate().  It would be a serious problem if we cannot do that.