NFSv4: Fix a nfs4_state_manager() race

[ Upstream commit ed1cc05aa1f7fe8197d300e914afc28ab9818f89 ]

If the NFS4CLNT_RUN_MANAGER flag got set just before we cleared
NFS4CLNT_MANAGER_RUNNING, then we might have won the race against
nfs4_schedule_state_manager(), and are responsible for handling the
recovery situation.

Fixes: aeabb3c96186 ("NFSv4: Fix a NFSv4 state manager deadlock")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
index ed789e0..457b2b2 100644 (file)
--- a/fs/nfs/nfs4state.c
+++ b/fs/nfs/nfs4state.c
@@ -2710,6 +2710,13 @@ static void nfs4_state_manager(struct nfs_client *clp)
                nfs4_end_drain_session(clp);
                nfs4_clear_state_manager_bit(clp);
 
+               if (test_bit(NFS4CLNT_RUN_MANAGER, &clp->cl_state) &&
+                   !test_and_set_bit(NFS4CLNT_MANAGER_RUNNING,
+                                     &clp->cl_state)) {
+                       memflags = memalloc_nofs_save();
+                       continue;
+               }
+
                if (!test_and_set_bit(NFS4CLNT_RECALL_RUNNING, &clp->cl_state)) {
                        if (test_and_clear_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state)) {
                                nfs_client_return_marked_delegations(clp);