From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 99A39201256 for ; Tue, 4 Mar 2025 12:27:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741091269; cv=none; b=M3h5LYiZJMzmtyiRRZFiJw25MP+IRNIQMw4D4j7ibq0Flt1vsmpwnbCVofcTos+06D9q9f7hFcDIkajJQGwa/5ewcdFNJ5lElwrWeiXMMkdw4Mo4+Ex1eajO3aUmWm3VlWzVHRkv3YbivUn5qc5YA0qFMMm9ZEgfCZflbd9n97I= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741091269; c=relaxed/simple; bh=8SG1vcxjBrlM4+h7kPFugDVKW5xS7P9qptFBXoccjj4=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=quIUNq4KJXfM1cnSGFuxZpOTTAUN3l07k/X1aqaYNEiaJXC05cgummwlnVQ9/WvQuuLOh7PlgyRZ7uLmqsTao+jj1i8Z9JaDVEbsqMP9OaQ5/HIv5TLLPt3/nHXw/V23VTPviMQBahruHCmBBvW9DNDfcs3sXqgHlOkR/+Z2QNA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=GofIVKbM; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="GofIVKbM" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6BB19C4CEE5; Tue, 4 Mar 2025 12:27:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1741091269; bh=8SG1vcxjBrlM4+h7kPFugDVKW5xS7P9qptFBXoccjj4=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=GofIVKbMxD0VmYNEtJ/7qth/jueXHc8ku0pgBFLQKKj79OED0M+MXl5wROfm07fRs +pRlf5M+4ppE2ISSyMPiOJDWo41NlvwiHrkOwyuT7cMYgW1ZGtKoavERJjGhr0hwDy h5v+hSXxXTs3MTQocPOHOtO2VA1V5En3C3c9ohuZVXEaybR2tm5FC2lClTXAngvWr2 Yx9GD/3J4LI0XriVCyT71kpjNY40WHgXHXrZW3JYhoum5Di/94JLpqACnn4/InxZca /59xMnbyvB1JOthlrbQLDsQgr7YBtVGfwyuNqZCIpByS58XWj0xs9XXfxfnuHL00Z4 ySrTacFWsGNNQ== Message-ID: Subject: Re: [PATCH V3 2/2] NFSD: allow client to use write delegation stateid for READ From: Jeff Layton To: Dai Ngo , chuck.lever@oracle.com, neilb@suse.de, okorniev@redhat.com, tom@talpey.com Cc: linux-nfs@vger.kernel.org, sagi@grimberg.me Date: Tue, 04 Mar 2025 07:27:47 -0500 In-Reply-To: <1741059224-4846-3-git-send-email-dai.ngo@oracle.com> References: <1741059224-4846-1-git-send-email-dai.ngo@oracle.com> <1741059224-4846-3-git-send-email-dai.ngo@oracle.com> Autocrypt: addr=jlayton@kernel.org; prefer-encrypt=mutual; keydata=mQINBE6V0TwBEADXhJg7s8wFDwBMEvn0qyhAnzFLTOCHooMZyx7XO7dAiIhDSi7G1NPxw n8jdFUQMCR/GlpozMFlSFiZXiObE7sef9rTtM68ukUyZM4pJ9l0KjQNgDJ6Fr342Htkjxu/kFV1Wv egyjnSsFt7EGoDjdKqr1TS9syJYFjagYtvWk/UfHlW09X+jOh4vYtfX7iYSx/NfqV3W1D7EDi0PqV T2h6v8i8YqsATFPwO4nuiTmL6I40ZofxVd+9wdRI4Db8yUNA4ZSP2nqLcLtFjClYRBoJvRWvsv4lm 0OX6MYPtv76hka8lW4mnRmZqqx3UtfHX/hF/zH24Gj7A6sYKYLCU3YrI2Ogiu7/ksKcl7goQjpvtV YrOOI5VGLHge0awt7bhMCTM9KAfPc+xL/ZxAMVWd3NCk5SamL2cE99UWgtvNOIYU8m6EjTLhsj8sn VluJH0/RcxEeFbnSaswVChNSGa7mXJrTR22lRL6ZPjdMgS2Km90haWPRc8Wolcz07Y2se0xpGVLEQ cDEsvv5IMmeMe1/qLZ6NaVkNuL3WOXvxaVT9USW1+/SGipO2IpKJjeDZfehlB/kpfF24+RrK+seQf CBYyUE8QJpvTZyfUHNYldXlrjO6n5MdOempLqWpfOmcGkwnyNRBR46g/jf8KnPRwXs509yAqDB6sE LZH+yWr9LQZEwARAQABtCVKZWZmIExheXRvbiA8amxheXRvbkBwb29jaGllcmVkcy5uZXQ+iQI7BB MBAgAlAhsDBgsJCAcDAgYVCAIJCgsEFgIDAQIeAQIXgAUCTpXWPAIZAQAKCRAADmhBGVaCFc65D/4 gBLNMHopQYgG/9RIM3kgFCCQV0pLv0hcg1cjr+bPI5f1PzJoOVi9s0wBDHwp8+vtHgYhM54yt43uI 7Htij0RHFL5eFqoVT4TSfAg2qlvNemJEOY0e4daljjmZM7UtmpGs9NN0r9r50W82eb5Kw5bc/r0km R/arUS2st+ecRsCnwAOj6HiURwIgfDMHGPtSkoPpu3DDp/cjcYUg3HaOJuTjtGHFH963B+f+hyQ2B rQZBBE76ErgTDJ2Db9Ey0kw7VEZ4I2nnVUY9B5dE2pJFVO5HJBMp30fUGKvwaKqYCU2iAKxdmJXRI ONb7dSde8LqZahuunPDMZyMA5+mkQl7kpIpR6kVDIiqmxzRuPeiMP7O2FCUlS2DnJnRVrHmCljLkZ Wf7ZUA22wJpepBligemtSRSbqCyZ3B48zJ8g5B8xLEntPo/NknSJaYRvfEQqGxgk5kkNWMIMDkfQO lDSXZvoxqU9wFH/9jTv1/6p8dHeGM0BsbBLMqQaqnWiVt5mG92E1zkOW69LnoozE6Le+12DsNW7Rj iR5K+27MObjXEYIW7FIvNN/TQ6U1EOsdxwB8o//Yfc3p2QqPr5uS93SDDan5ehH59BnHpguTc27Xi QQZ9EGiieCUx6Zh2ze3X2UW9YNzE15uKwkkuEIj60NvQRmEDfweYfOfPVOueC+iFifbQgSmVmZiBM YXl0b24gPGpsYXl0b25AcmVkaGF0LmNvbT6JAjgEEwECACIFAk6V0q0CGwMGCwkIBwMCBhUIAgkKC wQWAgMBAh4BAheAAAoJEAAOaEEZVoIViKUQALpvsacTMWWOd7SlPFzIYy2/fjvKlfB/Xs4YdNcf9q LqF+lk2RBUHdR/dGwZpvw/OLmnZ8TryDo2zXVJNWEEUFNc7wQpl3i78r6UU/GUY/RQmOgPhs3epQC 3PMJj4xFx+VuVcf/MXgDDdBUHaCTT793hyBeDbQuciARDJAW24Q1RCmjcwWIV/pgrlFa4lAXsmhoa c8UPc82Ijrs6ivlTweFf16VBc4nSLX5FB3ls7S5noRhm5/Zsd4PGPgIHgCZcPgkAnU1S/A/rSqf3F LpU+CbVBDvlVAnOq9gfNF+QiTlOHdZVIe4gEYAU3CUjbleywQqV02BKxPVM0C5/oVjMVx3bri75n1 TkBYGmqAXy9usCkHIsG5CBHmphv9MHmqMZQVsxvCzfnI5IO1+7MoloeeW/lxuyd0pU88dZsV/riHw 87i2GJUJtVlMl5IGBNFpqoNUoqmvRfEMeXhy/kUX4Xc03I1coZIgmwLmCSXwx9MaCPFzV/dOOrju2 xjO+2sYyB5BNtxRqUEyXglpujFZqJxxau7E0eXoYgoY9gtFGsspzFkVNntamVXEWVVgzJJr/EWW0y +jNd54MfPRqH+eCGuqlnNLktSAVz1MvVRY1dxUltSlDZT7P2bUoMorIPu8p7ZCg9dyX1+9T6Muc5d Hxf/BBP/ir+3e8JTFQBFOiLNdFtB9KZWZmIExheXRvbiA8amxheXRvbkBzYW1iYS5vcmc+iQI4BBM BAgAiBQJOldK9AhsDBgsJCAcDAgYVCAIJCgsEFgIDAQIeAQIXgAAKCRAADmhBGVaCFWgWD/0ZRi4h N9FK2BdQs9RwNnFZUr7JidAWfCrs37XrA/56olQl3ojn0fQtrP4DbTmCuh0SfMijB24psy1GnkPep naQ6VRf7Dxg/Y8muZELSOtsv2CKt3/02J1BBitrkkqmHyni5fLLYYg6fub0T/8Kwo1qGPdu1hx2BQ RERYtQ/S5d/T0cACdlzi6w8rs5f09hU9Tu4qV1JLKmBTgUWKN969HPRkxiojLQziHVyM/weR5Reu6 FZVNuVBGqBD+sfk/c98VJHjsQhYJijcsmgMb1NohAzwrBKcSGKOWJToGEO/1RkIN8tqGnYNp2G+aR 685D0chgTl1WzPRM6mFG1+n2b2RR95DxumKVpwBwdLPoCkI24JkeDJ7lXSe3uFWISstFGt0HL8Eew P8RuGC8s5h7Ct91HMNQTbjgA+Vi1foWUVXpEintAKgoywaIDlJfTZIl6Ew8ETN/7DLy8bXYgq0Xzh aKg3CnOUuGQV5/nl4OAX/3jocT5Cz/OtAiNYj5mLPeL5z2ZszjoCAH6caqsF2oLyAnLqRgDgR+wTQ T6gMhr2IRsl+cp8gPHBwQ4uZMb+X00c/Amm9VfviT+BI7B66cnC7Zv6Gvmtu2rEjWDGWPqUgccB7h dMKnKDthkA227/82tYoFiFMb/NwtgGrn5n2vwJyKN6SEoygGrNt0SI84y6hEVbQlSmVmZiBMYXl0b 24gPGpsYXl0b25AcHJpbWFyeWRhdGEuY29tPokCOQQTAQIAIwUCU4xmKQIbAwcLCQgHAwIBBhUIAg kKCwQWAgMBAh4BAheAAAoJEAAOaEEZVoIV1H0P/j4OUTwFd7BBbpoSp695qb6HqCzWMuExsp8nZjr uymMaeZbGr3OWMNEXRI1FWNHMtcMHWLP/RaDqCJil28proO+PQ/yPhsr2QqJcW4nr91tBrv/MqItu AXLYlsgXqp4BxLP67bzRJ1Bd2x0bWXurpEXY//VBOLnODqThGEcL7jouwjmnRh9FTKZfBDpFRaEfD FOXIfAkMKBa/c9TQwRpx2DPsl3eFWVCNuNGKeGsirLqCxUg5kWTxEorROppz9oU4HPicL6rRH22Ce 6nOAON2vHvhkUuO3GbffhrcsPD4DaYup4ic+DxWm+DaSSRJ+e1yJvwi6NmQ9P9UAuLG93S2MdNNbo sZ9P8k2mTOVKMc+GooI9Ve/vH8unwitwo7ORMVXhJeU6Q0X7zf3SjwDq2lBhn1DSuTsn2DbsNTiDv qrAaCvbsTsw+SZRwF85eG67eAwouYk+dnKmp1q57LDKMyzysij2oDKbcBlwB/TeX16p8+LxECv51a sjS9TInnipssssUDrHIvoTTXWcz7Y5wIngxDFwT8rPY3EggzLGfK5Zx2Q5S/N0FfmADmKknG/D8qG IcJE574D956tiUDKN4I+/g125ORR1v7bP+OIaayAvq17RP+qcAqkxc0x8iCYVCYDouDyNvWPGRhbL UO7mlBpjW9jK9e2fvZY9iw3QzIPGKtClKZWZmIExheXRvbiA8amVmZi5sYXl0b25AcHJpbWFyeWRh dGEuY29tPokCOQQTAQIAIwUCU4xmUAIbAwcLCQgHAwIBBhUIAgkKCwQWAgMBAh4BAheAAAoJEAAOa EEZVoIVzJoQALFCS6n/FHQS+hIzHIb56JbokhK0AFqoLVzLKzrnaeXhE5isWcVg0eoV2oTScIwUSU apy94if69tnUo4Q7YNt8/6yFM6hwZAxFjOXR0ciGE3Q+Z1zi49Ox51yjGMQGxlakV9ep4sV/d5a50 M+LFTmYSAFp6HY23JN9PkjVJC4PUv5DYRbOZ6Y1+TfXKBAewMVqtwT1Y+LPlfmI8dbbbuUX/kKZ5d dhV2736fgyfpslvJKYl0YifUOVy4D1G/oSycyHkJG78OvX4JKcf2kKzVvg7/Rnv+AueCfFQ6nGwPn 0P91I7TEOC4XfZ6a1K3uTp4fPPs1Wn75X7K8lzJP/p8lme40uqwAyBjk+IA5VGd+CVRiyJTpGZwA0 jwSYLyXboX+Dqm9pSYzmC9+/AE7lIgpWj+3iNisp1SWtHc4pdtQ5EU2SEz8yKvDbD0lNDbv4ljI7e flPsvN6vOrxz24mCliEco5DwhpaaSnzWnbAPXhQDWb/lUgs/JNk8dtwmvWnqCwRqElMLVisAbJmC0 BhZ/Ab4sph3EaiZfdXKhiQqSGdK4La3OTJOJYZphPdGgnkvDV9Pl1QZ0ijXQrVIy3zd6VCNaKYq7B AKidn5g/2Q8oio9Tf4XfdZ9dtwcB+bwDJFgvvDYaZ5bI3ln4V3EyW5i2NfXazz/GA/I/ZtbsigCFc 8ftCBKZWZmIExheXRvbiA8amxheXRvbkBrZXJuZWwub3JnPokCOAQTAQIAIgUCWe8u6AIbAwYLCQg HAwIGFQgCCQoLBBYCAwECHgECF4AACgkQAA5oQRlWghUuCg/+Lb/xGxZD2Q1oJVAE37uW308UpVSD 2tAMJUvFTdDbfe3zKlPDTuVsyNsALBGclPLagJ5ZTP+Vp2irAN9uwBuacBOTtmOdz4ZN2tdvNgozz uxp4CHBDVzAslUi2idy+xpsp47DWPxYFIRP3M8QG/aNW052LaPc0cedYxp8+9eiVUNpxF4SiU4i9J DfX/sn9XcfoVZIxMpCRE750zvJvcCUz9HojsrMQ1NFc7MFT1z3MOW2/RlzPcog7xvR5ENPH19ojRD CHqumUHRry+RF0lH00clzX/W8OrQJZtoBPXv9ahka/Vp7kEulcBJr1cH5Wz/WprhsIM7U9pse1f1g Yy9YbXtWctUz8uvDR7shsQxAhX3qO7DilMtuGo1v97I/Kx4gXQ52syh/w6EBny71CZrOgD6kJwPVV AaM1LRC28muq91WCFhs/nzHozpbzcheyGtMUI2Ao4K6mnY+3zIuXPygZMFr9KXE6fF7HzKxKuZMJO aEZCiDOq0anx6FmOzs5E6Jqdpo/mtI8beK+BE7Va6ni7YrQlnT0i3vaTVMTiCThbqsB20VrbMjlhp f8lfK1XVNbRq/R7GZ9zHESlsa35ha60yd/j3pu5hT2xyy8krV8vGhHvnJ1XRMJBAB/UYb6FyC7S+m QZIQXVeAA+smfTT0tDrisj1U5x6ZB9b3nBg65kc= Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.54.3 (3.54.3-1.fc41) Precedence: bulk X-Mailing-List: linux-nfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Mon, 2025-03-03 at 19:33 -0800, Dai Ngo wrote: > Allow READ using write delegation stateid granted on OPENs with > OPEN4_SHARE_ACCESS_WRITE only, to accommodate clients whose WRITE > implementation may unavoidably do (e.g., due to buffer cache > constraints). >=20 > When a write delegation is granted for OPEN with OPEN4_SHARE_ACCESS_WRITE= , > a new pair of nfsd_file and struct file are allocated with read access > and added to nfs4_file's fi_fds[]. This is to allow the client to use > the delegation stateid to do reads. >=20 > No additional actions is needed when the delegation is returned. The > nfsd_file for read remains attached to the nfs4_file and is freed when > the open stateid is closed. >=20 > Suggested-by: Chuck Lever > Signed-off-by: Dai Ngo > --- > fs/nfsd/nfs4state.c | 41 ++++++++++++++++++++++++++++++++++------- > 1 file changed, 34 insertions(+), 7 deletions(-) >=20 > diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c > index b533225e57cf..d2c6c43b5d0c 100644 > --- a/fs/nfsd/nfs4state.c > +++ b/fs/nfsd/nfs4state.c > @@ -6126,6 +6126,30 @@ nfs4_delegation_stat(struct nfs4_delegation *dp, s= truct svc_fh *currentfh, > return rc =3D=3D 0; > } > =20 > +/* > + * Add NFS4_SHARE_ACCESS_READ to the write delegation granted on OPEN > + * with NFS4_SHARE_ACCESS_READ by allocating separate nfsd_file and > + * struct file to be used for read with delegation stateid. > + * > + */ > +static void > +nfs4_add_rdaccess_to_wrdeleg(struct svc_rqst *rqstp, struct svc_fh *fh, > + struct nfs4_ol_stateid *stp) Let's call this nfsd4_add_rdaccess_to_wrdeleg(). > +{ > + struct nfs4_file *fp; > + struct nfsd_file *nf =3D NULL; > + > + if (nfsd_file_acquire_opened(rqstp, fh, NFSD_MAY_READ, NULL, &nf)) > + return; This function should return an error if nfsd_file_acquire_opened() fails, and the caller should not give out the delegation in that case. > + fp =3D stp->st_stid.sc_file; > + spin_lock(&fp->fi_lock); > + __nfs4_file_get_access(fp, NFS4_SHARE_ACCESS_READ); > + set_access(NFS4_SHARE_ACCESS_READ, stp); > + fp =3D stp->st_stid.sc_file; > + fp->fi_fds[O_RDONLY] =3D nf; > + spin_unlock(&fp->fi_lock); > +} > + > /* > * The Linux NFS server does not offer write delegations to NFSv4.0 > * clients in order to avoid conflicts between write delegations and > @@ -6151,8 +6175,9 @@ nfs4_delegation_stat(struct nfs4_delegation *dp, st= ruct svc_fh *currentfh, > * open or lock state. > */ > static void > -nfs4_open_delegation(struct nfsd4_open *open, struct nfs4_ol_stateid *st= p, > - struct svc_fh *currentfh) > +nfs4_open_delegation(struct svc_rqst *rqstp, struct nfsd4_open *open, > + struct nfs4_ol_stateid *stp, struct svc_fh *currentfh, > + struct svc_fh *fh) > { > bool deleg_ts =3D open->op_deleg_want & OPEN4_SHARE_ACCESS_WANT_DELEG_T= IMESTAMPS; > struct nfs4_openowner *oo =3D openowner(stp->st_stateowner); > @@ -6207,6 +6232,10 @@ nfs4_open_delegation(struct nfsd4_open *open, stru= ct nfs4_ol_stateid *stp, > dp->dl_cb_fattr.ncf_cur_fsize =3D stat.size; > dp->dl_cb_fattr.ncf_initial_cinfo =3D nfsd4_change_attribute(&stat); > trace_nfsd_deleg_write(&dp->dl_stid.sc_stateid); > + > + if ((open->op_share_access & NFS4_SHARE_ACCESS_BOTH) =3D=3D > + NFS4_SHARE_ACCESS_WRITE) > + nfs4_add_rdaccess_to_wrdeleg(rqstp, fh, stp); nit: I'd also move the if statement above into nfsd4_add_rdaccess_to_wrdeleg(). > } else { > open->op_delegate_type =3D deleg_ts ? OPEN_DELEGATE_READ_ATTRS_DELEG : > OPEN_DELEGATE_READ; > @@ -6353,7 +6382,8 @@ nfsd4_process_open2(struct svc_rqst *rqstp, struct = svc_fh *current_fh, struct nf > * Attempt to hand out a delegation. No error return, because the > * OPEN succeeds even if we fail. > */ > - nfs4_open_delegation(open, stp, &resp->cstate.current_fh); > + nfs4_open_delegation(rqstp, open, stp, > + &resp->cstate.current_fh, current_fh); > =20 > /* > * If there is an existing open stateid, it must be updated and > @@ -7098,10 +7128,6 @@ nfs4_find_file(struct nfs4_stid *s, int flags) > =20 > switch (s->sc_type) { > case SC_TYPE_DELEG: > - spin_lock(&s->sc_file->fi_lock); > - ret =3D nfsd_file_get(s->sc_file->fi_deleg_file); > - spin_unlock(&s->sc_file->fi_lock); > - break; > case SC_TYPE_OPEN: > case SC_TYPE_LOCK: > if (flags & RD_STATE) > @@ -7277,6 +7303,7 @@ nfs4_preprocess_stateid_op(struct svc_rqst *rqstp, > status =3D find_cpntf_state(nn, stateid, &s); > if (status) > return status; > + > status =3D nfsd4_stid_check_stateid_generation(stateid, s, > nfsd4_has_session(cstate)); > if (status) I think this approach looks valid though. Nice work! --=20 Jeff Layton