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>

diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index 414a90d..efc45f2 100644 (file)
--- 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);