linux-kernel - Re: [GIT PULL] Ceph fixes for 5.1-rc7

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Message-ID: <c570c901c850b6308bc78fcc6c7308f0bc491cb1.camel@kernel.org>
Date:   Sun, 28 Apr 2019 12:18:00 -0400
From:   Jeff Layton <jlayton@...nel.org>
To:     Al Viro <viro@...iv.linux.org.uk>
Cc:     Linus Torvalds <torvalds@...ux-foundation.org>,
        Ilya Dryomov <idryomov@...il.com>, ceph-devel@...r.kernel.org,
        Linux List Kernel Mailing <linux-kernel@...r.kernel.org>,
        linux-cifs <linux-cifs@...r.kernel.org>
Subject: Re: [GIT PULL] Ceph fixes for 5.1-rc7

On Sun, 2019-04-28 at 16:52 +0100, Al Viro wrote:
> On Sun, Apr 28, 2019 at 11:47:58AM -0400, Jeff Layton wrote:
> 
> > We could stick that in ceph_dentry_info (->d_fsdata). We have a flags
> > field in there already.
> 
> Yes, but...  You have it freed in ->d_release(), AFAICS, and without
> any delays.  So lockless accesses will be trouble.

That's easy enough to fix -- we could add a rcu_head to it and call_rcu
in ceph_d_release instead of just freeing it immediately.

I guess if we find that d_fsdata is NULL, we can just treat it like we
currently do a negative dentry?
-- 
Jeff Layton <jlayton@...nel.org>