On Wed, 2019-05-29 at 10:17 +0800, Yan, Zheng wrote:
> On Tue, May 28, 2019 at 9:57 PM Jeff Layton <jlayton@xxxxxxxxxx> wrote:
> > On Thu, 2019-05-23 at 16:13 +0800, Yan, Zheng wrote:
> > > Signed-off-by: "Yan, Zheng" <zyan@xxxxxxxxxx>
> > > ---
> > > fs/ceph/mds_client.c | 8 ++++----
> > > 1 file changed, 4 insertions(+), 4 deletions(-)
> > >
> > > diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
> > > index 60e8ddbdfdc5..870754e9d572 100644
> > > --- a/fs/ceph/mds_client.c
> > > +++ b/fs/ceph/mds_client.c
> > > @@ -913,7 +913,7 @@ static int __choose_mds(struct ceph_mds_client *mdsc,
> > > struct inode *dir;
> > >
> > > rcu_read_lock();
> > > - parent = req->r_dentry->d_parent;
> > > + parent = READ_ONCE(req->r_dentry->d_parent);
> >
> > Can we use rcu_dereference() instead?
> >
>
> d_parent has no __rcu mark. It will cause sparse warning.
>
> Regards
> Yan, Zheng
>
Good point.
> > > dir = req->r_parent ? : d_inode_rcu(parent);
> > >
> > > if (!dir || dir->i_sb != mdsc->fsc->sb) {
> > > @@ -2131,8 +2131,8 @@ char *ceph_mdsc_build_path(struct dentry *dentry, int *plen, u64 *pbase,
> > > if (inode && ceph_snap(inode) == CEPH_SNAPDIR) {
> > > dout("build_path path+%d: %p SNAPDIR\n",
> > > pos, temp);
> > > - } else if (stop_on_nosnap && inode && dentry != temp &&
> > > - ceph_snap(inode) == CEPH_NOSNAP) {
> > > + } else if (stop_on_nosnap && dentry != temp &&
> > > + inode && ceph_snap(inode) == CEPH_NOSNAP) {
> >
> > ^^^ Unrelated delta?
> >
> > > spin_unlock(&temp->d_lock);
> > > pos++; /* get rid of any prepended '/' */
> > > break;
> > > @@ -2145,7 +2145,7 @@ char *ceph_mdsc_build_path(struct dentry *dentry, int *plen, u64 *pbase,
> > > memcpy(path + pos, temp->d_name.name, temp->d_name.len);
> > > }
> > > spin_unlock(&temp->d_lock);
> > > - temp = temp->d_parent;
> > > + temp = READ_ONCE(temp->d_parent);
> >
> > Better to use rcu_dereference() here.
> >
> > > /* Are we at the root? */
> > > if (IS_ROOT(temp))
> >
Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>
