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Subject: [PATCH v1 1/7] NFSD: Add nfsd4_encode_lock_owner4()
From:   Chuck Lever <cel@kernel.org>
To:     linux-nfs@vger.kernel.org
Cc:     Chuck Lever <chuck.lever@oracle.com>
Date:   Fri, 29 Sep 2023 09:58:53 -0400
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From: Chuck Lever <chuck.lever@oracle.com>

To improve readability and better align the LOCK encoders with the
XDR specification, add an explicit encoder named for the lock_owner4
type.

In particular, to avoid code duplication, use
nfsd4_encode_clientid4() to encode the clientid in the lock owner
rather than open-coding it.

It looks to me like nfs4_set_lock_denied() already clears the
clientid if it won't return an owner (cf: the nevermind: label). The
code in the XDR encoder appears to be redundant and can safely be
removed.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 fs/nfsd/nfs4xdr.c |   31 +++++++++++++++++++++----------
 1 file changed, 21 insertions(+), 10 deletions(-)

diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index d21aaa56c49a..9f7a6924ef5f 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -3976,6 +3976,20 @@ nfsd4_encode_getfh(struct nfsd4_compoundres *resp, __be32 nfserr,
 	return nfsd4_encode_nfs_fh4(xdr, &fhp->fh_handle);
 }
 
+static __be32
+nfsd4_encode_lock_owner4(struct xdr_stream *xdr, const clientid_t *clientid,
+			 const struct xdr_netobj *owner)
+{
+	__be32 status;
+
+	/* clientid */
+	status = nfsd4_encode_clientid4(xdr, clientid);
+	if (status != nfs_ok)
+		return status;
+	/* owner */
+	return nfsd4_encode_opaque(xdr, owner->data, owner->len);
+}
+
 /*
 * Including all fields other than the name, a LOCK4denied structure requires
 *   8(clientid) + 4(namelen) + 8(offset) + 8(length) + 4(type) = 32 bytes.
@@ -3984,10 +3998,10 @@ static __be32
 nfsd4_encode_lock_denied(struct xdr_stream *xdr, struct nfsd4_lock_denied *ld)
 {
 	struct xdr_netobj *conf = &ld->ld_owner;
-	__be32 *p;
+	__be32 *p, status;
 
 again:
-	p = xdr_reserve_space(xdr, 32 + XDR_LEN(conf->len));
+	p = xdr_reserve_space(xdr, XDR_UNIT * 5);
 	if (!p) {
 		/*
 		 * Don't fail to return the result just because we can't
@@ -4004,14 +4018,11 @@ nfsd4_encode_lock_denied(struct xdr_stream *xdr, struct nfsd4_lock_denied *ld)
 	p = xdr_encode_hyper(p, ld->ld_start);
 	p = xdr_encode_hyper(p, ld->ld_length);
 	*p++ = cpu_to_be32(ld->ld_type);
-	if (conf->len) {
-		p = xdr_encode_opaque_fixed(p, &ld->ld_clientid, 8);
-		p = xdr_encode_opaque(p, conf->data, conf->len);
-		kfree(conf->data);
-	}  else {  /* non - nfsv4 lock in conflict, no clientid nor owner */
-		p = xdr_encode_hyper(p, (u64)0); /* clientid */
-		*p++ = cpu_to_be32(0); /* length of owner name */
-	}
+	status = nfsd4_encode_lock_owner4(xdr, &ld->ld_clientid,
+					  &ld->ld_owner);
+	if (status != nfs_ok)
+		return status;
+
 	return nfserr_denied;
 }