diff options
| author | Chuck Lever <chuck.lever@oracle.com> | 2024-03-26 17:00:20 -0400 |
|---|---|---|
| committer | Chuck Lever <chuck.lever@oracle.com> | 2024-03-27 13:19:47 -0400 |
| commit | 99dc2ef0397d082b63404c01cf841cf80f1418dc (patch) | |
| tree | 6edb1130f0d5f142805389993935eb4af4fd0a45 /fs/nfsd | |
| parent | 6978bd6a913825eaf06629a02fc820d240d5fec6 (diff) | |
NFSD: CREATE_SESSION must never cache NFS4ERR_DELAY replies
There are one or two cases where CREATE_SESSION returns
NFS4ERR_DELAY in order to force the client to wait a bit and try
CREATE_SESSION again. However, after commit e4469c6cc69b ("NFSD: Fix
the NFSv4.1 CREATE_SESSION operation"), NFSD caches that response in
the CREATE_SESSION slot. Thus, when the client resends the
CREATE_SESSION, the server always returns the cached NFS4ERR_DELAY
response rather than actually executing the request and properly
recording its outcome. This blocks the client from making further
progress.
RFC 8881 Section 15.1.1.3 says:
> If NFS4ERR_DELAY is returned on an operation other than SEQUENCE
> that validly appears as the first operation of a request ... [t]he
> request can be retried in full without modification. In this case
> as well, the replier MUST avoid returning a response containing
> NFS4ERR_DELAY as the response to an initial operation of a request
> solely on the basis of its presence in the reply cache.
Neither the original NFSD code nor the discussion in section 18.36.4
refer explicitly to this important requirement, so I missed it.
Note also that not only must the server not cache NFS4ERR_DELAY, but
it has to not advance the CREATE_SESSION slot sequence number so
that it can properly recognize and accept the client's retry.
Reported-by: Dai Ngo <dai.ngo@oracle.com>
Fixes: e4469c6cc69b ("NFSD: Fix the NFSv4.1 CREATE_SESSION operation")
Tested-by: Dai Ngo <dai.ngo@oracle.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Diffstat (limited to 'fs/nfsd')
| -rw-r--r-- | fs/nfsd/nfs4state.c | 36 |
1 files changed, 25 insertions, 11 deletions
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index ee9aa4843443..5fcd93f7cb8c 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -3831,15 +3831,20 @@ nfsd4_create_session(struct svc_rqst *rqstp, else cs_slot = &unconf->cl_cs_slot; status = check_slot_seqid(cr_ses->seqid, cs_slot->sl_seqid, 0); - if (status) { - if (status == nfserr_replay_cache) { - status = nfsd4_replay_create_session(cr_ses, cs_slot); - goto out_free_conn; - } + switch (status) { + case nfs_ok: + cs_slot->sl_seqid++; + cr_ses->seqid = cs_slot->sl_seqid; + break; + case nfserr_replay_cache: + status = nfsd4_replay_create_session(cr_ses, cs_slot); + fallthrough; + case nfserr_jukebox: + /* The server MUST NOT cache NFS4ERR_DELAY */ + goto out_free_conn; + default: goto out_cache_error; } - cs_slot->sl_seqid++; - cr_ses->seqid = cs_slot->sl_seqid; /* RFC 8881 Section 18.36.4 Phase 3: Client ID confirmation. */ if (conf) { @@ -3859,10 +3864,8 @@ nfsd4_create_session(struct svc_rqst *rqstp, old = find_confirmed_client_by_name(&unconf->cl_name, nn); if (old) { status = mark_client_expired_locked(old); - if (status) { - old = NULL; - goto out_cache_error; - } + if (status) + goto out_expired_error; trace_nfsd_clid_replaced(&old->cl_clientid); } move_to_confirmed(unconf); @@ -3894,6 +3897,17 @@ nfsd4_create_session(struct svc_rqst *rqstp, expire_client(old); return status; +out_expired_error: + old = NULL; + /* + * Revert the slot seq_nr change so the server will process + * the client's resend instead of returning a cached response. + */ + if (status == nfserr_jukebox) { + cs_slot->sl_seqid--; + cr_ses->seqid = cs_slot->sl_seqid; + goto out_free_conn; + } out_cache_error: nfsd4_cache_create_session(cr_ses, cs_slot, status); out_free_conn: |