linux-kernel - Re: [PATCH 27/38] union-mount: In-kernel file copyup routines

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:	Wed, 04 Aug 2010 17:26:28 +0200
From:	Miklos Szeredi <miklos@...redi.hu>
To:	Valerie Aurora <vaurora@...hat.com>
CC:	viro@...iv.linux.org.uk, miklos@...redi.hu, jblunck@...e.de,
	hch@...radead.org, linux-kernel@...r.kernel.org,
	linux-fsdevel@...r.kernel.org, vaurora@...hat.com,
	Valdis.Kletnieks@...edu
Subject: Re: [PATCH 27/38] union-mount: In-kernel file copyup routines

On Tue, 15 Jun 2010, Valerie Aurora wrote:
> When a file on the read-only layer of a union mount is altered, it
> must be copied up to the topmost read-write layer.  This patch creates
> union_copyup() and its supporting routines.
> 
> Thanks to Valdis Kletnieks for a bug fix.

What happens if there's a crash in the middle of the copyup?

Possible solution is using rename to atomically "replace" the
underlying file.  That however introduces namespace issues: where to
put the temporary file which then needs to be deleted on "fsck.union"?

Miklos
--
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/