linux-kernel - Re: [PATCH 5/5] vfs: change nondirectory i

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: <20120425195343.GC27193@quack.suse.cz>
Date:	Wed, 25 Apr 2012 21:53:43 +0200
From:	Jan Kara <jack@...e.cz>
To:	"J. Bruce Fields" <bfields@...ldses.org>
Cc:	Al Viro <viro@...IV.linux.org.uk>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org,
	"J. Bruce Fields" <bfields@...hat.com>
Subject: Re: [PATCH 5/5] vfs: change nondirectory i_mutex ordering to fix
 quota deadlock

On Wed 25-04-12 11:28:58, J. Bruce Fields wrote:
> On Wed, Apr 25, 2012 at 11:22:09AM -0400, bfields@...ldses.org wrote:
> > diff --git a/fs/inode.c b/fs/inode.c
> > index 487c924..13d23b6 100644
> > --- a/fs/inode.c
> > +++ b/fs/inode.c
> > @@ -961,6 +961,17 @@ void unlock_new_inode(struct inode *inode)
> >  }
> >  EXPORT_SYMBOL(unlock_new_inode);
> >  
> > +/*
> > + * We order !IS_NOQUOTA files before ISNOQUOTA files, and by pointer
> > + * within each category.
> > + */
> > +static bool nondir_mutex_ordered(struct inode *inode1, struct inode *inode2)
> > +{
> > +	if (IS_NOQUOTA(inode1) == IS_NOQUOTA(inode2))
> > +		return inode1 < inode2;
> > +	return IS_NOQUOTA(inode2);
> > +}
> 
> This seems kind of awful.  Is it what you were thinking of originally,
> Al, and could we live with it?
  Yeah, it's pretty ugly and also racy. I'm just now testing patches that
would get rid of I_MUTEX_QUOTA usage for filesystems (except GFS2) and
quota code. GFS2 could be certainly dealt with as well (at least by
introducing a new GFS2 internal lock) so this ugly code can go away.

								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/