Patch "NFSD: Capture every CB state transition" has been added to the 5.10-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    NFSD: Capture every CB state transition

to the 5.10-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     nfsd-capture-every-cb-state-transition.patch
and it can be found in the queue-5.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit fc92f50d7a025c5f25ae3e948f2fffa1dd93a6d2
Author: Chuck Lever <chuck.lever@xxxxxxxxxx>
Date:   Fri May 14 15:56:31 2021 -0400

    NFSD: Capture every CB state transition
    
    [ Upstream commit 8476c69a7fa0f1f9705ec0caa4e97c08b5045779 ]
    
    We were missing one.
    
    As a clean-up, add a helper that sets the new CB state and fires
    a tracepoint. The tracepoint fires only when the state changes, to
    help reduce trace log noise.
    
    Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
    Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxx>
    Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c
index f5b7ad0847f20..2e6a4a9e59ca1 100644
--- a/fs/nfsd/nfs4callback.c
+++ b/fs/nfsd/nfs4callback.c
@@ -945,20 +945,26 @@ static int setup_callback_client(struct nfs4_client *clp, struct nfs4_cb_conn *c
 	return 0;
 }
 
+static void nfsd4_mark_cb_state(struct nfs4_client *clp, int newstate)
+{
+	if (clp->cl_cb_state != newstate) {
+		clp->cl_cb_state = newstate;
+		trace_nfsd_cb_state(clp);
+	}
+}
+
 static void nfsd4_mark_cb_down(struct nfs4_client *clp, int reason)
 {
 	if (test_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags))
 		return;
-	clp->cl_cb_state = NFSD4_CB_DOWN;
-	trace_nfsd_cb_state(clp);
+	nfsd4_mark_cb_state(clp, NFSD4_CB_DOWN);
 }
 
 static void nfsd4_mark_cb_fault(struct nfs4_client *clp, int reason)
 {
 	if (test_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags))
 		return;
-	clp->cl_cb_state = NFSD4_CB_FAULT;
-	trace_nfsd_cb_state(clp);
+	nfsd4_mark_cb_state(clp, NFSD4_CB_FAULT);
 }
 
 static void nfsd4_cb_probe_done(struct rpc_task *task, void *calldata)
@@ -968,10 +974,8 @@ static void nfsd4_cb_probe_done(struct rpc_task *task, void *calldata)
 	trace_nfsd_cb_done(clp, task->tk_status);
 	if (task->tk_status)
 		nfsd4_mark_cb_down(clp, task->tk_status);
-	else {
-		clp->cl_cb_state = NFSD4_CB_UP;
-		trace_nfsd_cb_state(clp);
-	}
+	else
+		nfsd4_mark_cb_state(clp, NFSD4_CB_UP);
 }
 
 static void nfsd4_cb_probe_release(void *calldata)
@@ -995,8 +999,7 @@ static const struct rpc_call_ops nfsd4_cb_probe_ops = {
  */
 void nfsd4_probe_callback(struct nfs4_client *clp)
 {
-	clp->cl_cb_state = NFSD4_CB_UNKNOWN;
-	trace_nfsd_cb_state(clp);
+	nfsd4_mark_cb_state(clp, NFSD4_CB_UNKNOWN);
 	set_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags);
 	nfsd4_run_cb(&clp->cl_cb_null);
 }
@@ -1009,11 +1012,10 @@ void nfsd4_probe_callback_sync(struct nfs4_client *clp)
 
 void nfsd4_change_callback(struct nfs4_client *clp, struct nfs4_cb_conn *conn)
 {
-	clp->cl_cb_state = NFSD4_CB_UNKNOWN;
+	nfsd4_mark_cb_state(clp, NFSD4_CB_UNKNOWN);
 	spin_lock(&clp->cl_lock);
 	memcpy(&clp->cl_cb_conn, conn, sizeof(struct nfs4_cb_conn));
 	spin_unlock(&clp->cl_lock);
-	trace_nfsd_cb_state(clp);
 }
 
 /*
@@ -1345,7 +1347,7 @@ nfsd4_run_cb_work(struct work_struct *work)
 	 * Don't send probe messages for 4.1 or later.
 	 */
 	if (!cb->cb_ops && clp->cl_minorversion) {
-		clp->cl_cb_state = NFSD4_CB_UP;
+		nfsd4_mark_cb_state(clp, NFSD4_CB_UP);
 		nfsd41_destroy_cb(cb);
 		return;
 	}