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[162.232.235.235]) by smtp.gmail.com with ESMTPSA id 5614622812f47-479a0169edfsm14002410b6e.9.2026.04.23.14.32.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 23 Apr 2026 14:32:38 -0700 (PDT) Message-ID: <4b02eb62822b3ca363188e48878fbeff636b05fa.camel@hammerspace.com> Subject: Re: Why does Linux nfs not set EXCHGID4_FLAG_SUPP_FENCE_OPS in NFSv4.2 mode? From: Trond Myklebust To: Takeshi Nishimura , Linux NFS Mailing List Date: Thu, 23 Apr 2026 17:32:37 -0400 In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.58.3 (3.58.3-1.fc43) Precedence: bulk X-Mailing-List: linux-nfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Thu, 2026-04-23 at 19:07 +0200, Takeshi Nishimura wrote: > ? >=20 > On Tue, Jan 7, 2025 at 4:41=E2=80=AFPM Takeshi Nishimura > wrote: > >=20 > > Why does Linux nfs not set EXCHGID4_FLAG_SUPP_FENCE_OPS in NFSv4.2 > > mode? > >=20 > > From https://datatracker.ietf.org/doc/html/rfc7862#section-14.1.4 > > =C2=A0=C2=A0 A client SHOULD request the EXCHGID4_FLAG_SUPP_FENCE_OPS > > capability > > =C2=A0=C2=A0 when it sends an EXCHANGE_ID operation.=C2=A0 The server S= HOULD set > > this > > =C2=A0=C2=A0 capability in the EXCHANGE_ID reply whether the client req= uests > > it or > > =C2=A0=C2=A0 not.=C2=A0 It is the server's return that determines wheth= er this > > =C2=A0=C2=A0 capability is in effect.=C2=A0 When it is in effect, the f= ollowing > > will > > =C2=A0=C2=A0 occur: > >=20 > > Why is Linux not doing this? 1. Minor versions are not allowed to introduce a feature and make it mandatory 2. Why bother, since the server is going to set the flag whether or not the client requested it? --=20 Trond Myklebust Linux NFS client maintainer, Hammerspace trondmy@kernel.org, trond.myklebust@hammerspace.com