[PATCH 5.14 05/48] nfsd: back channel stuck in SEQ4_STATUS_CB_PATH_DOWN

Greg Kroah-Hartman
2021-10-08T11:39:15Z

From: Dai Ngo <dai.ngo@oracle.com>

[ Upstream commit 02579b2ff8b0becfb51d85a975908ac4ab15fba8 ]

When the back channel enters SEQ4_STATUS_CB_PATH_DOWN state, the client
recovers by sending BIND_CONN_TO_SESSION but the server fails to recover
the back channel and leaves it as NFSD4_CB_DOWN.

Fix by enhancing nfsd4_bind_conn_to_session to probe the back channel
by calling nfsd4_probe_callback.

Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/nfsd/nfs4state.c | 16 +++++++++++++---
1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 3d805f5b1f5d..1c33a5255893 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -3570,7 +3570,7 @@ static struct nfsd4_conn *__nfsd4_find_conn(struct svc_xprt *xpt, struct nfsd4_s
}

static __be32 nfsd4_match_existing_connection(struct svc_rqst *rqst,
- struct nfsd4_session *session, u32 req)
+ struct nfsd4_session *session, u32 req, struct nfsd4_conn **conn)
{
struct nfs4_client *clp = session->se_client;
struct svc_xprt *xpt = rqst->rq_xprt;
@@ -3593,6 +3593,8 @@ static __be32 nfsd4_match_existing_connection(struct svc_rqst *rqst,
else
status = nfserr_inval;
spin_unlock(&clp->cl_lock);
+ if (status == nfs_ok && conn)
+ *conn = c;
return status;
}

@@ -3617,8 +3619,16 @@ __be32 nfsd4_bind_conn_to_session(struct svc_rqst *rqstp,
status = nfserr_wrong_cred;
if (!nfsd4_mach_creds_match(session->se_client, rqstp))
goto out;
- status = nfsd4_match_existing_connection(rqstp, session, bcts->dir);
- if (status == nfs_ok || status == nfserr_inval)
+ status = nfsd4_match_existing_connection(rqstp, session,
+ bcts->dir, &conn);
+ if (status == nfs_ok) {
+ if (bcts->dir == NFS4_CDFC4_FORE_OR_BOTH ||
+ bcts->dir == NFS4_CDFC4_BACK)
+ conn->cn_flags |= NFS4_CDFC4_BACK;
+ nfsd4_probe_callback(session->se_client);
+ goto out;
+ }
+ if (status == nfserr_inval)
goto out;
status = nfsd4_map_bcts_dir(&bcts->dir);
if (status)
--
2.33.0