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From: Yiannis Marangos <yiannis.marangos@gmail.com>
To: Duy Nguyen <pclouds@gmail.com>
Cc: Git Mailing List <git@vger.kernel.org>
Subject: Re: [PATCH v5] Verify index file before we opportunistically update it
Date: Thu, 10 Apr 2014 14:57:43 +0300	[thread overview]
Message-ID: <20140410115743.GA1446@abyss.utx.wifi> (raw)
In-Reply-To: <CACsJy8D9dsxOA6xVmhxa7N20OxEQ1a63rQm6QCtwq9ThG6E3RA@mail.gmail.com>

On Thu, Apr 10, 2014 at 05:40:55PM +0700, Duy Nguyen wrote:
> verify_hdr() is a bit expensive because you need to digest the whole
> index file (could big as big as 14MB on webkit). Could we get away
> without it? I mean, is it enough that we pick the last 20 bytes and
> compare it with istate->sha1? If we only need 20 bytes, pread() may be
> better than mmap().
> 
> The chance of SHA-1 collision is small enough for us to ignore, I
> think. And if a client updates the index without updating the trailing
> sha-1, the index is broken and we don't have to worry about
> overwriting it.

That's true, I will commit version 6 in a bit.

  reply	other threads:[~2014-04-10 11:57 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-04-09 22:06 [PATCH] Verify index file before we opportunistically update it Yiannis Marangos
2014-04-09 22:06 ` Yiannis Marangos
2014-04-09 22:34 ` [PATCH v2] " Yiannis Marangos
2014-04-09 23:05   ` Junio C Hamano
2014-04-09 22:52 ` [PATCH v3] " Yiannis Marangos
2014-04-10  5:22 ` [PATCH v4] " Yiannis Marangos
2014-04-10  5:34 ` [PATCH v5] " Yiannis Marangos
2014-04-10 10:40   ` Duy Nguyen
2014-04-10 11:57     ` Yiannis Marangos [this message]
2014-04-10 16:57     ` Junio C Hamano
2014-04-10 13:11 ` [PATCH v6] " Yiannis Marangos
2014-04-10 18:31 ` [PATCH v7 1/2] Add xpread() and xpwrite() Yiannis Marangos
2014-04-10 18:31   ` [PATCH v7 2/2] Verify index file before we opportunistically update it Yiannis Marangos
2014-04-10 19:28     ` Junio C Hamano
2014-04-11  2:57       ` Duy Nguyen
2014-04-11 19:24         ` Junio C Hamano
2014-04-11 20:43           ` Junio C Hamano
2014-04-11 23:30             ` Yiannis Marangos
2014-04-12  0:10             ` Duy Nguyen
2014-04-12  4:19               ` Junio C Hamano
2014-04-12  7:05                 ` Junio C Hamano
2014-04-12 10:13                 ` Duy Nguyen
2014-04-14 18:50                   ` Junio C Hamano
2014-04-11  7:47       ` Torsten Bögershausen
2014-04-11 15:58         ` Yiannis Marangos
2014-04-11 10:36       ` Duy Nguyen
2014-04-10 18:35   ` [PATCH v7 1/2] Add xpread() and xpwrite() Junio C Hamano
2014-04-10 18:44     ` Yiannis Marangos
2014-04-10 18:54 ` [PATCH v8 1/2] Add xpread() Yiannis Marangos
2014-04-10 19:12   ` Johannes Sixt
2014-04-10 19:20     ` Junio C Hamano

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