From: Al Viro <viro@ZenIV.linux.org.uk>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Sasha Levin <sasha.levin@oracle.com>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Dave Jones <davej@redhat.com>,
"Eric W. Biederman" <ebiederm@xmission.com>
Subject: Re: fs: lockup on rename_mutex in fs/dcache.c:1035
Date: Sun, 26 Oct 2014 23:42:30 +0000 [thread overview]
Message-ID: <20141026234230.GU7996@ZenIV.linux.org.uk> (raw)
In-Reply-To: <CA+55aFxfDgYsp9SAxWTy2sS0KLrErPUd06bEYJf=siCmaBu52w@mail.gmail.com>
On Sun, Oct 26, 2014 at 04:33:11PM -0700, Linus Torvalds wrote:
> On Sun, Oct 26, 2014 at 2:57 PM, Al Viro <viro@zeniv.linux.org.uk> wrote:
> > .. snip ..
> > in d_walk(), __list_del() instead of list_del() in __dentry_kill(), d_u.d_child
> > turning into d_child everywhere, while d_alias turns into d_u.d_alias...
> >
> > It looks like that way we would get no retries on the second pass. Comments?
>
> Since I missed the whole issue with d_child.next, I'm not sure any
> comments from me would be helpful.
>
> It does sound like trying to be more careful with d_child and using
> d_alias instead is a good idea. d_alias is only used under the dentry
> lock, and not in any horribly subtle situations, right? So that sounds
> like a good change regardless of this particular fix - making the
> union happen in a less nasty place..
OK... See vfs.git#experimental-d_walk - the first commit there moves
d_rcu from d_child to d_alias, the second is basically "skip the killed
siblings rather than restarting the tree walk".
prev parent reply other threads:[~2014-10-26 23:42 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-26 1:39 fs: lockup on rename_mutex in fs/dcache.c:1035 Sasha Levin
2014-10-26 2:56 ` Al Viro
2014-10-26 3:01 ` Eric W. Biederman
2014-10-26 3:06 ` Al Viro
2014-10-26 3:51 ` Al Viro
2014-10-26 3:57 ` Al Viro
2014-10-26 18:56 ` Linus Torvalds
2014-10-26 19:13 ` Al Viro
2014-10-26 21:57 ` Al Viro
2014-10-26 23:33 ` Linus Torvalds
2014-10-26 23:42 ` Al Viro [this message]
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