linux-kernel - Re: sysfs: tagged directories not merged completely yet

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: <48EBEE0B.6080009@kernel.org>
Date:	Wed, 08 Oct 2008 08:17:31 +0900
From:	Tejun Heo <tj@...nel.org>
To:	"Eric W. Biederman" <ebiederm@...ssion.com>
CC:	Al Viro <viro@...IV.linux.org.uk>,
	Benjamin Thery <benjamin.thery@...l.net>,
	Greg KH <greg@...ah.com>, linux-kernel@...r.kernel.org,
	"Serge E. Hallyn" <serue@...ibm.com>,
	Al Viro <viro@....linux.org.uk>,
	Linus Torvalds <torvalds@...ux-foundation.org>
Subject: Re: sysfs: tagged directories not merged completely yet

Hello, a bit of additions after some sleep.

Tejun Heo wrote:
> Eric W. Biederman wrote:
> IIRC, the original readdir implementation put a cursor entry to walk
> through the children list.  The implementation was horribly broken in
> a number of different ways (ISTR problems with locking and multiple
> and different type of walkers) and I just gutted out all the
> complexity out and made it simple as getting it correct was far more
> important and there seemed to be little need for optimization.
> 
> Yeah, using RCU sounds like a plan.

Heh... it did sound like a plan but I don't think the plan would solve
the problem.  filldir can't be put in rcu read critical section.  :-p

>> The revalidate on access model doesn't appear to have a way to track
>> remote renames.  Something sysfs supports.
> 
> Yeap, IIRC, one of the reasons why sysfs wasn't converted over to
> sysfs was because sysfs guarantees inode doesn't change over rename or
> move so that notifications keep working over renames.

s/over to sysfs/over to revalidation/ and s/inode/dentry/.  Maybe we can
just ignore dnotify?  :-(

Thanks.

-- 
tejun
--
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/