NFS: Ensure that all nfs lock contexts have a valid open context

Force the lock context to keep a reference to the parent open
context so that we can guarantee the validity of the latter.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

1 files changed, 9 insertions, 4 deletions

diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index 414a90d48493..efc45f22c581 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -885,10 +885,14 @@ struct nfs_lock_context *nfs_get_lock_context(struct nfs_open_context *ctx)
                 spin_lock(&inode->i_lock);
                 res = __nfs_find_lock_context(ctx);
                 if (res == NULL) {
-                        list_add_tail_rcu(&new->list, &ctx->lock_context.list);
-                        new->open_context = ctx;
-                        res = new;
-                        new = NULL;
+                        new->open_context = get_nfs_open_context(ctx);
+                        if (new->open_context) {
+                                list_add_tail_rcu(&new->list,
+                                                &ctx->lock_context.list);
+                                res = new;
+                                new = NULL;
+                        } else
+                                res = ERR_PTR(-EBADF);
                 }
                 spin_unlock(&inode->i_lock);
                 kfree(new);
@@ -906,6 +910,7 @@ void nfs_put_lock_context(struct nfs_lock_context *l_ctx)
                 return;
         list_del_rcu(&l_ctx->list);
         spin_unlock(&inode->i_lock);
+        put_nfs_open_context(ctx);
         kfree_rcu(l_ctx, rcu_head);
 }
 EXPORT_SYMBOL_GPL(nfs_put_lock_context);