linux-kernel - Re: replace() system call needed (was Re: EXT4-ish "fixes" in UBIFS)

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]

Date:	Tue, 31 Mar 2009 00:11:52 +0200
From:	Pavel Machek <pavel@....cz>
To:	Ric Wheeler <rwheeler@...hat.com>
Cc:	Artem Bityutskiy <dedekind@...dex.ru>,
	Artem Bityutskiy <Artem.Bityutskiy@...ia.com>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: replace() system call needed (was Re: EXT4-ish "fixes" in
	UBIFS)

Hi!

>> My proposal is 
>>
>> rename() stays.
>>
>> replace(src, bar) is rename that ensures that bar will contain valid
>> data after powerfail.
>>   
>
> Surely the only way to "insure" this is to spin up the drive, write the  
> meta-data and data back and make sure that it is not held in volatile  
> write cache?

Well, no. "will contain valid data" but may contain _old_ valid data.

So the way to do that would be "wait until you have to spin disk up
anyway or until timeout, then write data first, then do rename".

AFAICT that's semantics gnome (etc) wants.
									Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
--
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/