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>

1 files changed, 4 insertions, 0 deletions

diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
index da8d73ed9e0f..6a7107ae6b72 100644
--- 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,