[PATCH v3 5/8] NFSD: Block DESTROY_CLIENTID only when there are ongoing async COPY operations

[cel@kernel.org]

From: Chuck Lever <chuck.lever@oracle.com>

Currently __destroy_client() consults the nfs4_client's async_copies
list to determine whether there are ongoing async COPY operations.
However, NFSD now keeps copy state in that list even when the
async copy has completed, to enable OFFLOAD_STATUS to find the
COPY results for a while after the COPY has completed.

DESTROY_CLIENTID should not be blocked if the client's async_copies
list contains state for only completed copy operations.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 fs/nfsd/nfs4proc.c  | 30 ++++++++++++++++++++++++++++++
 fs/nfsd/nfs4state.c |  2 +-
 fs/nfsd/state.h     |  1 +
 3 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index 0918d05c54a1..4d44b785a580 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -1278,6 +1278,36 @@ nfsd4_clone(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 	return status;
 }
 
+/**
+ * nfsd4_has_active_async_copies - Check for ongoing copy operations
+ * @clp: Client to be checked
+ *
+ * NFSD maintains state for async COPY operations after they complete,
+ * and this state remains in the nfs4_client's async_copies list.
+ * Ongoing copies should block the destruction of the nfs4_client, but
+ * completed copies should not.
+ *
+ * Return values:
+ *   %true: At least one active async COPY is ongoing
+ *   %false: No active async COPY operations were found
+ */
+bool nfsd4_has_active_async_copies(struct nfs4_client *clp)
+{
+	struct nfsd4_copy *copy;
+	bool result = false;
+
+	spin_lock(&clp->async_lock);
+	list_for_each_entry(copy, &clp->async_copies, copies) {
+		if (!test_bit(NFSD4_COPY_F_COMPLETED, &copy->cp_flags) &&
+		    !test_bit(NFSD4_COPY_F_STOPPED, &copy->cp_flags)) {
+			result = true;
+			break;
+		}
+	}
+	spin_unlock(&clp->async_lock);
+	return result;
+}
+
 static void nfs4_put_copy(struct nfsd4_copy *copy)
 {
 	if (!refcount_dec_and_test(&copy->refcount))
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 551d2958ec29..cde5ba69d7a5 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -3487,7 +3487,7 @@ static bool client_has_state(struct nfs4_client *clp)
 #endif
 		|| !list_empty(&clp->cl_delegations)
 		|| !list_empty(&clp->cl_sessions)
-		|| !list_empty(&clp->async_copies);
+		|| nfsd4_has_active_async_copies(clp);
 }
 
 static __be32 copy_impl_id(struct nfs4_client *clp,
diff --git a/fs/nfsd/state.h b/fs/nfsd/state.h
index 35b3564c065f..6c84c0900ec4 100644
--- a/fs/nfsd/state.h
+++ b/fs/nfsd/state.h
@@ -742,6 +742,7 @@ extern void nfsd4_init_cb(struct nfsd4_callback *cb, struct nfs4_client *clp,
 extern bool nfsd4_run_cb(struct nfsd4_callback *cb);
 extern void nfsd4_shutdown_callback(struct nfs4_client *);
 extern void nfsd4_shutdown_copy(struct nfs4_client *clp);
+bool nfsd4_has_active_async_copies(struct nfs4_client *clp);
 extern struct nfs4_client_reclaim *nfs4_client_to_reclaim(struct xdr_netobj name,
 				struct xdr_netobj princhash, struct nfsd_net *nn);
 extern bool nfs4_has_reclaimed_state(struct xdr_netobj name, struct nfsd_net *nn);
-- 
2.47.0