NFSv4: Ensure correct locking when accessing the 'lock_states' list

There are currently 2 places in the state recovery code, where we do not
take sufficient precautions before accessing the state->lock_states. In
both cases, we should be holding the state->state_lock.

Reported-by: Pascal Bouchareine <pascal@gandi.net>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
index da8d73e..6a7107a 100644 (file)
--- a/fs/nfs/nfs4state.c
+++ b/fs/nfs/nfs4state.c
@@ -1156,11 +1156,13 @@ restart:
                if (status >= 0) {
                        status = nfs4_reclaim_locks(state, ops);
                        if (status >= 0) {
+                               spin_lock(&state->state_lock);
                                list_for_each_entry(lock, &state->lock_states, ls_locks) {
                                        if (!(lock->ls_flags & NFS_LOCK_INITIALIZED))
                                                printk("%s: Lock reclaim failed!\n",
                                                        __func__);
                                }
+                               spin_unlock(&state->state_lock);
                                nfs4_put_open_state(state);
                                goto restart;
                        }
@@ -1224,10 +1226,12 @@ static void nfs4_clear_open_state(struct nfs4_state *state)
        clear_bit(NFS_O_RDONLY_STATE, &state->flags);
        clear_bit(NFS_O_WRONLY_STATE, &state->flags);
        clear_bit(NFS_O_RDWR_STATE, &state->flags);
+       spin_lock(&state->state_lock);
        list_for_each_entry(lock, &state->lock_states, ls_locks) {
                lock->ls_seqid.flags = 0;
                lock->ls_flags &= ~NFS_LOCK_INITIALIZED;
        }
+       spin_unlock(&state->state_lock);
 }
 
 static void nfs4_reset_seqids(struct nfs_server *server,