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Subject: [PATCH v3 6/7] NFSD: Make nfsd4_setattr() wait before returning
 NFS4ERR_DELAY
From:   Chuck Lever <chuck.lever@oracle.com>
To:     linux-nfs@vger.kernel.org
Date:   Mon, 08 Aug 2022 09:53:06 -0400
Message-ID: <165996678693.2637.18109478792874390277.stgit@manet.1015granger.net>
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References: <165996657035.2637.4745479232455341597.stgit@manet.1015granger.net>
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nfsd_setattr() can kick off a CB_RECALL (via
notify_change() -> break_lease()) if a delegation is present. Before
returning NFS4ERR_DELAY, give the client holding that delegation a
chance to return it and then retry the nfsd_setattr() again, once.

Link: https://bugzilla.linux-nfs.org/show_bug.cgi?id=354
Tested-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 fs/nfsd/nfs4proc.c |   19 ++++++++++++++++---
 1 file changed, 16 insertions(+), 3 deletions(-)

diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index 14f07d3d6c48..5b18a71f1043 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -1142,7 +1142,7 @@ nfsd4_setattr(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 {
 	struct nfsd4_setattr *setattr = &u->setattr;
 	__be32 status = nfs_ok;
-	int err;
+	int err, retries;
 
 	if (setattr->sa_iattr.ia_valid & ATTR_SIZE) {
 		status = nfs4_preprocess_stateid_op(rqstp, cstate,
@@ -1173,8 +1173,21 @@ nfsd4_setattr(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 				&setattr->sa_label);
 	if (status)
 		goto out;
-	status = nfsd_setattr(rqstp, &cstate->current_fh, &setattr->sa_iattr,
-				0, (time64_t)0);
+
+	retries = 1;
+	do {
+		status = nfsd_setattr(rqstp, &cstate->current_fh,
+				      &setattr->sa_iattr, 0, (time64_t)0);
+		if (status != nfserr_jukebox)
+			break;
+		if (!retries--)
+			break;
+		if (!nfsd4_wait_for_delegreturn(rqstp, &cstate->current_fh))
+			break;
+
+		fh_clear_pre_post_attrs(&cstate->current_fh);
+	} while (1);
+
 out:
 	fh_drop_write(&cstate->current_fh);
 	return status;