From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6B91C436355; Wed, 10 Jun 2026 15:19:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781104751; cv=none; b=NMuAYVPRZIJ22Ri7oAK6h9Wt2c546tif2chDs39iNeBhZZhDZdExYdsN6QQIS7YEEF9MEG8TzCjCiD7e4tV+4HTYoRaSGicmtcq06XcdLLyjO96hzb2RJ0lDiT/3RgftlDUSn+rbxEjCQesrwS83L7H2eUjZEXTi2sZ5EiA6j1U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781104751; c=relaxed/simple; bh=S0Ky2JhkU+qxxqs9GrI8yBq0+8HRXL9LO9HIjL7lADk=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=Cp7PaZ3C51/WRq1DPgVeK+TZg0AxXaFdM77xaeCMd0/5Nxq/YG/w655IX97qPTnWtDVWVE7AVD/nwlrD4dNsRIxSnf16RRjhDwGGQwuRC2RkQsuhtmupbiLUekz69xDNy/PHvWexLm+Dzpyypwpy+wSWhcTxyjF871regNB/jDE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=TBnxgJMz; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="TBnxgJMz" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5041C1F00893; Wed, 10 Jun 2026 15:19:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1781104750; bh=7pKlOdKoZbfb9MxMklBB0qriBd1HSJEh74QMbDCWZ7U=; h=Subject:From:To:Cc:Date:In-Reply-To:References; b=TBnxgJMzbjFshxDAklAj9D5QtqujnpYaTMhi7IUSVAsLufAkdYBB7eYRf0uJCN7KI KVboHKCFOrT0vZM6FjYH/Ha5vbrOf6HRVLTYUcGxjgnF6QJtD9VAXmnlPEk9qa40FB dXWVYfTsKm4/URJpG+NyakgsTHnHkerFtyK38c5yR3zdT77uAVXfup7IaZpoFgRcyq IbulXRXcTiDut8XVEl86V5ry/u1vaEmR7Ubeib7kGMoQ5Dh321KWjd6asaMqQYDEpP nn2ztQ5ecM1jUmMf91yvDMKqJbuJbmrK+mIQNNSmK/D3x7uhrZVAom4Sy38uXoFyHl 3K3ov6J3o/CNw== Message-ID: Subject: Re: [PATCH v5 07/21] nfsd: add callback encoding and decoding linkages for CB_NOTIFY From: Jeff Layton To: Chuck Lever , Chuck Lever , NeilBrown , Olga Kornievskaia , Dai Ngo , Tom Talpey , Trond Myklebust , Anna Schumaker , Jonathan Corbet , Shuah Khan Cc: Steven Rostedt , Alexander Aring , Amir Goldstein , Jan Kara , Alexander Viro , Christian Brauner , Calum Mackay , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-nfs@vger.kernel.org Date: Wed, 10 Jun 2026 11:19:06 -0400 In-Reply-To: <35918046-66e3-4361-adc3-bce328ce9821@app.fastmail.com> References: <20260522-dir-deleg-v5-0-542cddfad576@kernel.org> <20260522-dir-deleg-v5-7-542cddfad576@kernel.org> <35918046-66e3-4361-adc3-bce328ce9821@app.fastmail.com> Autocrypt: addr=jlayton@kernel.org; prefer-encrypt=mutual; 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text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.60.2 (3.60.2-1.fc44) Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Mon, 2026-06-08 at 12:52 -0400, Chuck Lever wrote: >=20 > On Fri, May 22, 2026, at 3:42 PM, Jeff Layton wrote: > > Add routines for encoding and decoding CB_NOTIFY messages. These call > > into the code generated by xdrgen to do the actual encoding and > > decoding. >=20 > The commit message needs to explain that the encoder is not yet functiona= l. > Something like: "The encoder is a stub; payload encoding (stateid, fh, an= d > cna_changes) is deferred." >=20 Ok. >=20 > > diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c > > index 25bbf5b8814d..ea3e7deb06fa 100644 > > --- a/fs/nfsd/nfs4callback.c > > +++ b/fs/nfsd/nfs4callback.c > > @@ -865,6 +865,51 @@ static void encode_stateowner(struct xdr_stream= =20 > > *xdr, struct nfs4_stateowner *so > > xdr_encode_opaque(p, so->so_owner.data, so->so_owner.len); > > } > >=20 > > +static void nfs4_xdr_enc_cb_notify(struct rpc_rqst *req, > > + struct xdr_stream *xdr, > > + const void *data) > > +{ > > + const struct nfsd4_callback *cb =3D data; > > + struct nfs4_cb_compound_hdr hdr =3D { > > + .ident =3D 0, > > + .minorversion =3D cb->cb_clp->cl_minorversion, > > + }; > > + struct CB_NOTIFY4args args =3D { }; > > + > > + WARN_ON_ONCE(hdr.minorversion =3D=3D 0); > > + > > + encode_cb_compound4args(xdr, &hdr); > > + encode_cb_sequence4args(xdr, cb, &hdr); > > + > > + /* > > + * FIXME: get stateid and fh from delegation. Inline the cna_changes > > + * buffer, and zero it. > > + */ > > + WARN_ON_ONCE(!xdrgen_encode_CB_NOTIFY4args(xdr, &args)); > > + > > + hdr.nops++; > > + encode_cb_nops(&hdr); > > +} >=20 > There are a number of problems with this, but since there are no > callers yet, we can let some of those issues stand. >=20 > What is problematic in the longer-term is that this is a client-side > encoder (since this is the server's NFSv4 callback client). >=20 > xdrgen_encode_CB_NOTIFY4args() is an argument encoder, which is > client-side functionality, but it resides in fs/nfsd/nfs4xdr_gen.c, > which is server-side. Let's not mix these purposes. >=20 > I replaced the comment and WARN_ON with this: >=20 > + xdr_stream_encode_u32(xdr, OP_CB_NOTIFY); > + > + /* FIXME: encode stateid, fh, and cna_changes from delegation */ >=20 > You can use xdrgen functions for individual data items, but for > full argument and response structures, only server-side is supported > at the moment. In the later patch that completes this code, I'll cover > the other fields, which can be a mix of open code and xdrgen. >=20 The full argument encoder and decoder works just fine. When you say "supported" what do you mean, specifically? I'd really rather not go back to open-coding the encoders and decoders, particularly since CB_NOTIFY has one of the most complex argument structures in the protocol. >=20 > > diff --git a/fs/nfsd/state.h b/fs/nfsd/state.h > > index e1c40f8b5d01..790282781243 100644 > > --- a/fs/nfsd/state.h > > +++ b/fs/nfsd/state.h > > @@ -190,6 +190,13 @@ struct nfs4_cb_fattr { > > u64 ncf_cur_fsize; > > }; > >=20 > > +/* > > + * FIXME: the current backchannel encoder can't handle a send buffer l= onger > > + * than a single page (see bc_alloc/bc_free). > > + */ >=20 > Nit: The allocator function name is bc_malloc >=20 Will fix. --=20 Jeff Layton