[PATCH 4/4] nfsd: extra checks when freeing delegation stateids

[Jeff Layton <jlayton@kernel.org>]

We've had some reports of problems in the refcounting for delegation
stateids that we've yet to track down. Add some extra checks to ensure
that we've removed the object from various lists before freeing it.

Link: https://bugzilla.redhat.com/show_bug.cgi?id=2127067
Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
 fs/nfsd/nfs4state.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

This one may need adjustment after Dai fixes the use of openlockstateid
here.

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 90533f43fea9..490092a10285 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -1060,9 +1060,12 @@ static struct nfs4_ol_stateid * nfs4_alloc_open_stateid(struct nfs4_client *clp)
 
 static void nfs4_free_deleg(struct nfs4_stid *stid)
 {
-	struct nfs4_ol_stateid *stp = openlockstateid(stid);
+	struct nfs4_delegation *dp = delegstateid(stid);
 
-	WARN_ON(!list_empty(&stp->st_stid.sc_cp_list));
+	WARN_ON_ONCE(!list_empty(&stid->sc_cp_list));
+	WARN_ON_ONCE(!list_empty(&dp->dl_perfile));
+	WARN_ON_ONCE(!list_empty(&dp->dl_perclnt));
+	WARN_ON_ONCE(!list_empty(&dp->dl_recall_lru));
 	kmem_cache_free(deleg_slab, stid);
 	atomic_long_dec(&num_delegations);
 }
-- 
2.37.3