linux-kernel - Re: Crash when IO is being submitted and block size is changed

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: <20120628165357.GA6232@quack.suse.cz>
Date:	Thu, 28 Jun 2012 18:53:57 +0200
From:	Jan Kara <jack@...e.cz>
To:	Mikulas Patocka <mpatocka@...hat.com>
Cc:	Jan Kara <jack@...e.cz>, Alexander Viro <viro@...iv.linux.org.uk>,
	Jens Axboe <axboe@...nel.dk>,
	"Alasdair G. Kergon" <agk@...hat.com>,
	linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org,
	dm-devel@...hat.com
Subject: Re: Crash when IO is being submitted and block size is changed

On Thu 28-06-12 11:44:03, Mikulas Patocka wrote:
> On Thu, 28 Jun 2012, Jan Kara wrote:
> 
> > > Do you have any other ideas what to do with it?
> >   Yeah, it's nasty and neither solution looks particularly appealing. One
> > idea that came to my mind is: I'm trying to solve some races between direct
> > IO, buffered IO, hole punching etc. by a new mapping interval lock. I'm not
> > sure if it will go anywhere yet but if it does, we can fix the above race
> > by taking the mapping lock for the whole block device around setting block
> > size thus effectivelly disallowing any IO to it.
> > 
> > 								Honza
> > -- 
> > Jan Kara <jack@...e.cz>
> > SUSE Labs, CR
> 
> What races are you trying to solve? There used to be i_alloc_mem that 
> prevented direct i/o while the file is being truncated, but it disappeared 
> in recent kernels...
  i_alloc_sem has been replaced by inode_dio_wait() and friends. The
problem is mainly with hole punching - see the thread starting here:
http://www.spinics.net/lists/linux-ext4/msg32059.html

								Honza
--
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/