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
> > 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))
>
> --
> Jeff Layton <jlayton@xxxxxxxxxx>
>
