Merge: NFSD: Force all NFSv4.2 COPY requests to be synchronous

MR: https://gitlab.com/redhat/centos-stream/src/kernel/centos-stream-9/-/merge_requests/5660

JIRA: https://issues.redhat.com/browse/RHEL-64496  
CVE: CVE-2024-49974  

We are not including the patch highlighted in the CVE ("NFSD: Limit the number  
of concurrent async COPY operations"). Instead, we're addressing the CVE by  
including an upstream fix that disables async copy because the fix for async  
copy upstream is still incomplete. Once the async copy support has been  
completely fixed upstream, we will include the upstream patch that re-enables  
it in RHEL and include all the fixes.  

Signed-off-by: Olga Kornievskaia <okorniev@redhat.com>

Approved-by: Scott Mayhew <smayhew@redhat.com>
Approved-by: Benjamin Coddington <bcodding@redhat.com>
Approved-by: CKI KWF Bot <cki-ci-bot+kwf-gitlab-com@redhat.com>

Merged-by: Rado Vrbovsky <rvrbovsk@redhat.com>

Author: emmil

fs/nfsd/nfs4proc.c

@@ -1828,6 +1828,13 @@ nfsd4_copy(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 	__be32 status;
 	struct nfsd4_copy *async_copy = NULL;
 
+	/*
+	 * Currently, async COPY is not reliable. Force all COPY
+	 * requests to be synchronous to avoid client application
+	 * hangs waiting for COPY completion.
+	 */
+	nfsd4_copy_set_sync(copy, true);
+
 	copy->cp_clp = cstate->clp;
 	if (nfsd4_ssc_is_inter(copy)) {
 		trace_nfsd_copy_inter(copy);