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Subject: [PATCH 2/4] nfsd: allow open state ids to be revoked and then freed
From:   NeilBrown <neilb@suse.de>
To:     Chuck Lever <chuck.lever@oracle.com>
Cc:     linux-nfs@vger.kernel.org
Date:   Thu, 27 Jan 2022 15:58:10 +1100
Message-ID: <164325949070.23133.8692722614255991208.stgit@noble.brown>
In-Reply-To: <164325908579.23133.4781039121536248752.stgit@noble.brown>
References: <164325908579.23133.4781039121536248752.stgit@noble.brown>
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Revoking state through 'unlock_filesystem' now revokes any open states
found.  When the stateids are then freed by the client, the revoked
stateids will be cleaned up correctly.

Possibly the related lock states should be revoked too, but a
subsequent patch will do that for all lock state on the superblock.

Signed-off-by: NeilBrown <neilb@suse.de>
---
 fs/nfsd/nfs4state.c |   37 ++++++++++++++++++++++++++++++++++++-
 1 file changed, 36 insertions(+), 1 deletion(-)

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index ad02b4ebe1b6..6854546ebd08 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -1113,6 +1113,9 @@ nfs4_put_stid(struct nfs4_stid *s)
 		return;
 	}
 	idr_remove(&clp->cl_stateids, s->sc_stateid.si_opaque.so_id);
+	if (s->sc_type == NFS4_ADMIN_REVOKED_STID)
+		atomic_dec(&clp->cl_admin_revoked);
+	s->sc_type = 0;
 	nfs4_free_cpntf_statelist(clp->net, s);
 	spin_unlock(&clp->cl_lock);
 	s->sc_free(s);
@@ -1165,6 +1168,9 @@ static void destroy_unhashed_deleg(struct nfs4_delegation *dp)
 
 void nfs4_unhash_stid(struct nfs4_stid *s)
 {
+	struct nfs4_client *clp = s->sc_client;
+	if (s->sc_type == NFS4_ADMIN_REVOKED_STID)
+		atomic_dec(&clp->cl_admin_revoked);
 	s->sc_type = 0;
 }
 
@@ -1431,6 +1437,9 @@ static void put_ol_stateid_locked(struct nfs4_ol_stateid *stp,
 	}
 
 	idr_remove(&clp->cl_stateids, s->sc_stateid.si_opaque.so_id);
+	if (s->sc_type == NFS4_ADMIN_REVOKED_STID)
+		atomic_dec(&clp->cl_admin_revoked);
+	s->sc_type = 0;
 	list_add(&stp->st_locks, reaplist);
 }
 
@@ -1601,7 +1610,7 @@ void nfsd4_revoke_states(struct net *net, struct super_block *sb)
 	unsigned int idhashval;
 	unsigned short sc_types;
 
-	sc_types = 0;
+	sc_types = NFS4_OPEN_STID;
 
 	spin_lock(&nn->client_lock);
 	for (idhashval = 0; idhashval < CLIENT_HASH_MASK; idhashval++) {
@@ -1612,8 +1621,23 @@ void nfsd4_revoke_states(struct net *net, struct super_block *sb)
 			struct nfs4_stid *stid = find_one_sb_stid(clp, sb,
 								  sc_types);
 			if (stid) {
+				struct nfs4_ol_stateid *stp;
+
 				spin_unlock(&nn->client_lock);
 				switch (stid->sc_type) {
+				case NFS4_OPEN_STID:
+					stp = openlockstateid(stid);
+					mutex_lock_nested(&stp->st_mutex,
+							  OPEN_STATEID_MUTEX);
+					if (stid->sc_type == NFS4_OPEN_STID) {
+						release_all_access(stp);
+						stid->sc_type =
+							NFS4_ADMIN_REVOKED_STID;
+						atomic_inc(&clp->cl_admin_revoked);
+						/* FIXME revoke the locks */
+					}
+					mutex_unlock(&stp->st_mutex);
+					break;
 				}
 				nfs4_put_stid(stid);
 				spin_lock(&nn->client_lock);
@@ -6235,6 +6259,8 @@ nfsd4_free_stateid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 	stateid_t *stateid = &free_stateid->fr_stateid;
 	struct nfs4_stid *s;
 	struct nfs4_delegation *dp;
+	struct nfs4_ol_stateid *stp;
+	LIST_HEAD(reaplist);
 	struct nfs4_client *cl = cstate->clp;
 	__be32 ret = nfserr_bad_stateid;
 
@@ -6259,6 +6285,15 @@ nfsd4_free_stateid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 		spin_unlock(&cl->cl_lock);
 		ret = nfsd4_free_lock_stateid(stateid, s);
 		goto out;
+	case NFS4_ADMIN_REVOKED_STID:
+		stp = openlockstateid(s);
+		spin_unlock(&s->sc_lock);
+		if (unhash_open_stateid(stp, &reaplist))
+			put_ol_stateid_locked(stp, &reaplist);
+		spin_unlock(&cl->cl_lock);
+		free_ol_stateid_reaplist(&reaplist);
+		ret = nfs_ok;
+		goto out;
 	case NFS4_REVOKED_DELEG_STID:
 		spin_unlock(&s->sc_lock);
 		dp = delegstateid(s);