nfsd: Update callback sequnce id only CB_SEQUENCE success

When testing pnfs layout, nfsd got error NFS4ERR_SEQ_MISORDERED.
It is caused by nfs return NFS4ERR_DELAY before validate_seqid(),
don't update the sequnce id, but nfsd updates the sequnce id !!!

According to RFC5661 20.9.3,
" If CB_SEQUENCE returns an error, then the state of the slot
(sequence ID, cached reply) MUST NOT change. "

Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

2 files changed, 13 insertions, 2 deletions

diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c
index 8b1ac8d4f011..a49201835a97 100644
--- a/fs/nfsd/nfs4callback.c
+++ b/fs/nfsd/nfs4callback.c
@@ -455,6 +455,7 @@ static int decode_cb_sequence4res(struct xdr_stream *xdr,
         if (unlikely(status || cb->cb_status))
                 return status;
 
+        cb->cb_update_seq_nr = true;
         return decode_cb_sequence4resok(xdr, cb);
 }
 
@@ -875,6 +876,7 @@ static void nfsd4_cb_prepare(struct rpc_task *task, void *calldata)
         u32 minorversion = clp->cl_minorversion;
 
         cb->cb_minorversion = minorversion;
+        cb->cb_update_seq_nr = false;
         cb->cb_status = 0;
         if (minorversion) {
                 if (!nfsd41_cb_get_slot(clp, task))
@@ -892,9 +894,16 @@ static void nfsd4_cb_done(struct rpc_task *task, void *calldata)
                 clp->cl_minorversion);
 
         if (clp->cl_minorversion) {
-                /* No need for lock, access serialized in nfsd4_cb_prepare */
-                if (!task->tk_status)
+                /*
+                 * No need for lock, access serialized in nfsd4_cb_prepare
+                 *
+                 * RFC5661 20.9.3
+                 * If CB_SEQUENCE returns an error, then the state of the slot
+                 * (sequence ID, cached reply) MUST NOT change.
+                 */
+                if (cb->cb_update_seq_nr)
                         ++clp->cl_cb_session->se_cb_seq_nr;
+
                 clear_bit(0, &clp->cl_cb_slot_busy);
                 rpc_wake_up_next(&clp->cl_cb_waitq);
                 dprintk("%s: freed slot, new seqid=%d\n", __func__,
@@ -1091,6 +1100,7 @@ void nfsd4_init_cb(struct nfsd4_callback *cb, struct nfs4_client *clp,
         cb->cb_ops = ops;
         INIT_WORK(&cb->cb_work, nfsd4_run_cb_work);
         cb->cb_status = 0;
+        cb->cb_update_seq_nr = false;
         cb->cb_need_restart = false;
 }
 
diff --git a/fs/nfsd/state.h b/fs/nfsd/state.h
index dbc4f85a5008..4ed7c2ae95eb 100644
--- a/fs/nfsd/state.h
+++ b/fs/nfsd/state.h
@@ -68,6 +68,7 @@ struct nfsd4_callback {
         struct nfsd4_callback_ops *cb_ops;
         struct work_struct cb_work;
         int cb_status;
+        bool cb_update_seq_nr;
         bool cb_need_restart;
 };