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From: Yiannis Marangos <yiannis.marangos@gmail.com>
To: "Torsten Bögershausen" <tboegi@web.de>
Cc: Junio C Hamano <gitster@pobox.com>, git@vger.kernel.org
Subject: Re: [PATCH v7 2/2] Verify index file before we opportunistically update it
Date: Fri, 11 Apr 2014 18:58:57 +0300	[thread overview]
Message-ID: <20140411155857.GA12742@abyss.hitronhub.home> (raw)
In-Reply-To: <53479DFD.4020702@web.de>

On Fri, Apr 11, 2014 at 09:47:09AM +0200, Torsten Bögershausen wrote:
>   6. process A applies a commit:
>       - read the index into memory
>       - take the lock
>       - update the index file on disc
>       - release the lock

So here we can have race condition. Maybe we should implement Duy's
idea of verifying the sha1 in write_index()?


> The new code works like this:
>
>   8. process B applies a commit:
>       - take the lock
>       - verifies tha the index file on disc has the same sha as the one read before
>       # And if not: What do we do? die() or retry() ?
>       - update the index file on disc
>       - release the lock

IMO, we must never die() if we want to do opportunistic update and we
should never retry because it's a bit expensive if we do opportunistic update.


--
Yiannis

  reply	other threads:[~2014-04-11 15:59 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
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 [this message]
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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