Patch "nfsd: make nfsd4_run_cb a bool return function" has been added to the 5.15-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

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

    nfsd: make nfsd4_run_cb a bool return function

to the 5.15-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-make-nfsd4_run_cb-a-bool-return-function.patch
and it can be found in the queue-5.15 subdirectory.

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



commit 1445086e973d9fe86433d4d5e6d1ebf33625e8de
Author: Jeff Layton <jlayton@xxxxxxxxxx>
Date:   Mon Sep 26 14:41:01 2022 -0400

    nfsd: make nfsd4_run_cb a bool return function
    
    [ Upstream commit b95239ca4954a0d48b19c09ce7e8f31b453b4216 ]
    
    queue_work can return false and not queue anything, if the work is
    already queued. If that happens in the case of a CB_RECALL, we'll have
    taken an extra reference to the stid that will never be put. Ensure we
    throw a warning in that case.
    
    Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
    Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>

diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c
index face8908a40b1..39989c14c8a1e 100644
--- a/fs/nfsd/nfs4callback.c
+++ b/fs/nfsd/nfs4callback.c
@@ -1373,11 +1373,21 @@ void nfsd4_init_cb(struct nfsd4_callback *cb, struct nfs4_client *clp,
 	cb->cb_holds_slot = false;
 }
 
-void nfsd4_run_cb(struct nfsd4_callback *cb)
+/**
+ * nfsd4_run_cb - queue up a callback job to run
+ * @cb: callback to queue
+ *
+ * Kick off a callback to do its thing. Returns false if it was already
+ * on a queue, true otherwise.
+ */
+bool nfsd4_run_cb(struct nfsd4_callback *cb)
 {
 	struct nfs4_client *clp = cb->cb_clp;
+	bool queued;
 
 	nfsd41_cb_inflight_begin(clp);
-	if (!nfsd4_queue_cb(cb))
+	queued = nfsd4_queue_cb(cb);
+	if (!queued)
 		nfsd41_cb_inflight_end(clp);
+	return queued;
 }
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index e98306c69f424..61978ad43a0f7 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -4874,14 +4874,13 @@ static void nfsd_break_one_deleg(struct nfs4_delegation *dp)
 	 * we know it's safe to take a reference.
 	 */
 	refcount_inc(&dp->dl_stid.sc_count);
-	nfsd4_run_cb(&dp->dl_recall);
+	WARN_ON_ONCE(!nfsd4_run_cb(&dp->dl_recall));
 }
 
 /* Called from break_lease() with flc_lock held. */
 static bool
 nfsd_break_deleg_cb(struct file_lock *fl)
 {
-	bool ret = false;
 	struct nfs4_delegation *dp = (struct nfs4_delegation *)fl->fl_owner;
 	struct nfs4_file *fp = dp->dl_stid.sc_file;
 	struct nfs4_client *clp = dp->dl_stid.sc_client;
@@ -4907,7 +4906,7 @@ nfsd_break_deleg_cb(struct file_lock *fl)
 	fp->fi_had_conflict = true;
 	nfsd_break_one_deleg(dp);
 	spin_unlock(&fp->fi_lock);
-	return ret;
+	return false;
 }
 
 /**
diff --git a/fs/nfsd/state.h b/fs/nfsd/state.h
index b3477087a9fc3..e2daef3cc0034 100644
--- a/fs/nfsd/state.h
+++ b/fs/nfsd/state.h
@@ -692,7 +692,7 @@ extern void nfsd4_probe_callback_sync(struct nfs4_client *clp);
 extern void nfsd4_change_callback(struct nfs4_client *clp, struct nfs4_cb_conn *);
 extern void nfsd4_init_cb(struct nfsd4_callback *cb, struct nfs4_client *clp,
 		const struct nfsd4_callback_ops *ops, enum nfsd4_cb_op op);
-extern void nfsd4_run_cb(struct nfsd4_callback *cb);
+extern bool nfsd4_run_cb(struct nfsd4_callback *cb);
 extern int nfsd4_create_callback_queue(void);
 extern void nfsd4_destroy_callback_queue(void);
 extern void nfsd4_shutdown_callback(struct nfs4_client *);