[PATCH 1/2] NFSv4: Fix a nfs4_state_manager() race

[trondmy@kernel.org]

From: Trond Myklebust <trond.myklebust@hammerspace.com>

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>
---
 fs/nfs/nfs4state.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
index e079987af4a3..0bc160fbabec 100644
--- a/fs/nfs/nfs4state.c
+++ b/fs/nfs/nfs4state.c
@@ -2703,6 +2703,13 @@ 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);
-- 
2.41.0