Re: [PATCH] mds: update dentry lease for async create

[Jeff Layton <jlayton@kernel.org>]

On Wed, 2020-03-04 at 08:55 -0500, Jeff Layton wrote:
> On Wed, 2020-03-04 at 21:22 +0800, Yan, Zheng wrote:
> > Otherwise ceph_d_delete() may return 1 for the dentry, which makes
> > dput() prune the dentry and clear parent dir's complete flag.
> > 
> > Signed-off-by: "Yan, Zheng" <zyan@redhat.com>
> > ---
> >  fs/ceph/file.c | 3 +++
> >  1 file changed, 3 insertions(+)
> > 
> > diff --git a/fs/ceph/file.c b/fs/ceph/file.c
> > index 53321bf517c2..671b141aedfe 100644
> > --- a/fs/ceph/file.c
> > +++ b/fs/ceph/file.c
> > @@ -480,6 +480,9 @@ static int try_prep_async_create(struct inode *dir, struct dentry *dentry,
> >  	if (d_in_lookup(dentry)) {
> >  		if (!__ceph_dir_is_complete(ci))
> >  			goto no_async;
> > +		spin_lock(&dentry->d_lock);
> > +		di->lease_shared_gen = atomic_read(&ci->i_shared_gen);
> > +		spin_unlock(&dentry->d_lock);
> >  	} else if (atomic_read(&ci->i_shared_gen) !=
> >  		   READ_ONCE(di->lease_shared_gen)) {
> >  		goto no_async;
> 
> Good catch, merged into testing (with small update to changelog
> s/mds:/ceph:/)
> 

One related comment though. This patch implies that lease_shared_gen is
protected by the d_lock, but it's not held when it's assigned in
ceph_lookup. Should it be?

-- 
Jeff Layton <jlayton@kernel.org>