NFSv4: Don't use the delegation->inode in nfs_mark_return_delegation()

nfs_mark_return_delegation() is usually called without any locking, and
so it is not safe to dereference delegation->inode. Since the inode is
only used to discover the nfs_client anyway, it makes more sense to
have the callers pass a valid pointer to the nfs_server as a parameter.

Reported-by: Ian Kent <raven@themaw.net>
Cc: stable@kernel.org
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 8 insertions, 8 deletions

diff --git a/fs/nfs/delegation.c b/fs/nfs/delegation.c
index dd25c2aec375..321a66bc3846 100644
--- a/fs/nfs/delegation.c
+++ b/fs/nfs/delegation.c
@@ -398,12 +398,11 @@ int nfs_inode_return_delegation(struct inode *inode)
         return err;
 }
 
-static void nfs_mark_return_delegation(struct nfs_delegation *delegation)
+static void nfs_mark_return_delegation(struct nfs_server *server,
+                struct nfs_delegation *delegation)
 {
-        struct nfs_client *clp = NFS_SERVER(delegation->inode)->nfs_client;
-
         set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
-        set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
+        set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
 }
 
 /**
@@ -441,7 +440,7 @@ static void nfs_mark_return_all_delegation_types(struct nfs_server *server,
                 if ((delegation->type == (FMODE_READ|FMODE_WRITE)) && !(flags & FMODE_WRITE))
                         continue;
                 if (delegation->type & flags)
-                        nfs_mark_return_delegation(delegation);
+                        nfs_mark_return_delegation(server, delegation);
         }
 }
 
@@ -508,7 +507,7 @@ static void nfs_mark_return_unreferenced_delegations(struct nfs_server *server)
         list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
                 if (test_and_clear_bit(NFS_DELEGATION_REFERENCED, &delegation->flags))
                         continue;
-                nfs_mark_return_delegation(delegation);
+                nfs_mark_return_delegation(server, delegation);
         }
 }
 
@@ -539,7 +538,8 @@ void nfs_expire_unreferenced_delegations(struct nfs_client *clp)
 int nfs_async_inode_return_delegation(struct inode *inode,
                                       const nfs4_stateid *stateid)
 {
-        struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
+        struct nfs_server *server = NFS_SERVER(inode);
+        struct nfs_client *clp = server->nfs_client;
         struct nfs_delegation *delegation;
 
         rcu_read_lock();
@@ -549,7 +549,7 @@ int nfs_async_inode_return_delegation(struct inode *inode,
                 rcu_read_unlock();
                 return -ENOENT;
         }
-        nfs_mark_return_delegation(delegation);
+        nfs_mark_return_delegation(server, delegation);
         rcu_read_unlock();
 
         nfs_delegation_run_state_manager(clp);