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From: Junio C Hamano <gitster@pobox.com>
To: Philip Oakley <philipoakley@iee.email>
Cc: "Jason Hatton" <jhatton@globalfinishing.com>,
	"René Scharfe" <l.s.r@web.de>,
	"git@vger.kernel.org" <git@vger.kernel.org>
Subject: Re: [PATCH] Prevent git from rehashing 4GBi files
Date: Fri, 06 May 2022 09:36:43 -0700	[thread overview]
Message-ID: <xmqqr156obxg.fsf@gitster.g> (raw)
In-Reply-To: <f3f883cb-9141-6871-0f3d-3d3293a17f5f@iee.email> (Philip Oakley's message of "Fri, 6 May 2022 11:22:57 +0100")

Philip Oakley <philipoakley@iee.email> writes:

> This "Munge" above isn't telling the reader 'why'/'what' is going on.
> The comment should in some way highlight that a zero size result is
> special, and that we have the roll over issue when the stored in 32 bits
> - the double duty of racy vs changed in the stat data heuristic.
> Synonyms of 'munge' ?
>
>
>> + */
>> +unsigned int munge_st_size(off_t st_size) {
>> +	unsigned int sd_size = st_size;
>> +
>> +	if(!sd_size && st_size)

Style.

>> +		return 0x80000000;
>> +	else
>> +		return sd_size;
>> +}

This may treat non-zero multiple of 4GiB as "not racy", but has
anybody double checked the concern Réne brought up earlier that a
4GiB file that was added and then got rewritten to 2GiB within the
same second would suddenly start getting treated as not racy?

The patch (the firnal version of it anyway) needs to be accompanied
by a handful of test additions to tickle corner cases like that.

Thanks, all, for working on this.

  reply	other threads:[~2022-05-06 16:37 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-05-06  0:26 Jason Hatton
2022-05-06  4:37 ` Torsten Bögershausen
2022-05-06 10:22 ` Philip Oakley
2022-05-06 16:36   ` Junio C Hamano [this message]
2022-05-06 21:17     ` Philip Oakley
2022-05-06 21:23       ` Junio C Hamano
2022-05-06 17:08 Jason Hatton
2022-05-06 18:32 ` Junio C Hamano
2022-05-07  2:15 Jason Hatton
     [not found] ` <1DFD3E42-3EF3-4420-8E01-748EF3DBE7A1@iee.email>
2022-05-07 15:22   ` René Scharfe
2022-05-10 22:45 ` Philip Oakley
2022-05-11 22:24   ` Philip Oakley
     [not found] <CY4PR16MB165501ED1B535592033C76F2AFC49@CY4PR16MB1655.namprd16.prod.outlook.com>
2022-05-07 18:10 ` Jason Hatton
     [not found] <philipoakley@iee.email>
2022-05-07 18:58 ` Jason D. Hatton

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