linux-kernel - Re: [sqlite] light weight write barriers

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <50A44267.6090103@vlnb.net>
Date:	Wed, 14 Nov 2012 20:16:23 -0500
From:	Vladislav Bolkhovitin <vst@...b.net>
To:	Alan Cox <alan@...rguk.ukuu.org.uk>
CC:	Howard Chu <hyc@...as.com>,
	General Discussion of SQLite Database 
	<sqlite-users@...ite.org>, Theodore Ts'o <tytso@....edu>,
	drh@...ci.com, linux-kernel@...r.kernel.org,
	linux-fsdevel@...r.kernel.org
Subject: Re: [sqlite] light weight write barriers


Alan Cox, on 11/13/2012 12:40 PM wrote:
>>> Barriers are pretty much universal as you need them for power off !
>>
>> I'm afraid, no storage (drives, if you like this term more) at the moment supports
>> barriers and, as far as I know the storage history, has never supported.
>
> The ATA cache flush is a write barrier, and given you have no NV cache
> visible to the controller it's the same thing.

The cache flush is cache flush. You can call it barrier, if you want to continue 
confusing yourself and others.

>> Instead, what storage does support in this area are:
>
> Yes - the devil is in the detail once you go beyond simple capabilities.

None of those details brings anything not solvable. For instance, I already 
described in this thread a simple way how requested order of commands can be 
carried through the stack and implemented that algorithm in SCST.

Vlad
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/