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 E488F33768B for ; Wed, 15 Oct 2025 16:53:46 +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=1760547228; cv=none; b=du3JRFKBitslT9Z5b7vp/rsHD9b4tGXuzPRo5GyMMY/QJ/3QsV5aVH6WaUJReV9dyH6bMoClFFu3sACUgGEmpebkcTJqYKE+AcPHLscgX9iIsKCc8wpzteLdeEX6ukI5tSgAQXpfkEPDrbQhQjgeK8nc/iCYh7s6JCMIxmB9Dxs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760547228; c=relaxed/simple; bh=ViuD0SaVns0m2WzZkgsKjC8pxsk1HXvSwrUQ8Pa/OSk=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=TIYvGEKCklzSCqkH4XreIAyiDl4Y0qGpLlhKn+G2qXfXmVABKcn0MkaWkg1IyoedDKPst6QdB7IXbGnwqpdi7nkKP2JiR31Xi706zRYLxIDMLcz93sCp4YdHKgrD6GtUiBb4E+W6dLn+1HHOCoJ5rPL6+acGrZVlubf9MlbbUQI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=X5kIg0OU; 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="X5kIg0OU" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D699EC4CEF9; Wed, 15 Oct 2025 16:53:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1760547226; bh=ViuD0SaVns0m2WzZkgsKjC8pxsk1HXvSwrUQ8Pa/OSk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=X5kIg0OU2Gn/MwO9MQcZ2UYVoPqRJ18C1EFkc8t9L3K9z1pmOgqNZso1ZwnhoJdTA lH1z7437XtW8abg39yYnPZLdBsAwYHD8VTriUrJ80myS4RpOoPuVOpOc2wKpNCDOjH xNzOz/ijLG01Xh3cNF3GW/sm5yivvj1mViZhbYE/yNZ/CtKYZ268/S9hTN0cdjJcNE ZdPJpMXk79IHrKithFkTmLQfEiyDclbWsyrr19amv5E+nWTOeV5xnD/egltVhNldqp PXBVY2VyhUHOJU8GUe4BCkEU//tPtM3A/IRs9kj4JKfZum1u9f7gLRWJxOdmpsiOx1 6RVuD2rD/5jsw== Date: Wed, 15 Oct 2025 12:53:44 -0400 From: Mike Snitzer To: Chuck Lever Cc: NeilBrown , Jeff Layton , Olga Kornievskaia , Dai Ngo , Tom Talpey , linux-nfs@vger.kernel.org, Chuck Lever Subject: Re: [PATCH v1] NFSD: Enable return of an updated stable_how to NFS clients Message-ID: References: <20251013190113.252097-1-cel@kernel.org> Precedence: bulk X-Mailing-List: linux-nfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20251013190113.252097-1-cel@kernel.org> On Mon, Oct 13, 2025 at 03:01:13PM -0400, Chuck Lever wrote: > From: Chuck Lever > > In a subsequent patch, nfsd_vfs_write() will promote an UNSTABLE > WRITE to be a FILE_SYNC WRITE. This indicates that the client does > not need a subsequent COMMIT operation, saving a round trip and > allowing the client to dispense with cached dirty data as soon as > it receives the server's WRITE response. > > This patch refactors nfsd_vfs_write() to return a possibly modified > stable_how value to its callers. No behavior change is expected. > > Signed-off-by: Chuck Lever > --- > fs/nfsd/nfs3proc.c | 2 +- > fs/nfsd/nfs4proc.c | 2 +- > fs/nfsd/nfsproc.c | 3 ++- > fs/nfsd/vfs.c | 11 ++++++----- > fs/nfsd/vfs.h | 6 ++++-- > fs/nfsd/xdr3.h | 2 +- > 6 files changed, 15 insertions(+), 11 deletions(-) > > Here's what I had in mind, based on a patch I did a year ago but > never posted. > > If nfsd_vfs_write() promotes an NFS_UNSTABLE write to NFS_FILE_SYNC, > it can now set *stable_how and the WRITE encoders will return the > updated value to the client. > > > diff --git a/fs/nfsd/nfs3proc.c b/fs/nfsd/nfs3proc.c > index b6d03e1ef5f7..ad14b34583bb 100644 > --- a/fs/nfsd/nfs3proc.c > +++ b/fs/nfsd/nfs3proc.c > @@ -236,7 +236,7 @@ nfsd3_proc_write(struct svc_rqst *rqstp) > resp->committed = argp->stable; > resp->status = nfsd_write(rqstp, &resp->fh, argp->offset, > &argp->payload, &cnt, > - resp->committed, resp->verf); > + &resp->committed, resp->verf); > resp->count = cnt; > resp->status = nfsd3_map_status(resp->status); > return rpc_success; > diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c > index 7f7e6bb23a90..2222bb283baf 100644 > --- a/fs/nfsd/nfs4proc.c > +++ b/fs/nfsd/nfs4proc.c > @@ -1285,7 +1285,7 @@ nfsd4_write(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate, > write->wr_how_written = write->wr_stable_how; > status = nfsd_vfs_write(rqstp, &cstate->current_fh, nf, > write->wr_offset, &write->wr_payload, > - &cnt, write->wr_how_written, > + &cnt, &write->wr_how_written, > (__be32 *)write->wr_verifier.data); > nfsd_file_put(nf); > > diff --git a/fs/nfsd/nfsproc.c b/fs/nfsd/nfsproc.c > index 8f71f5748c75..706401ed6f8d 100644 > --- a/fs/nfsd/nfsproc.c > +++ b/fs/nfsd/nfsproc.c > @@ -251,6 +251,7 @@ nfsd_proc_write(struct svc_rqst *rqstp) > struct nfsd_writeargs *argp = rqstp->rq_argp; > struct nfsd_attrstat *resp = rqstp->rq_resp; > unsigned long cnt = argp->len; > + u32 committed = NFS_DATA_SYNC; > > dprintk("nfsd: WRITE %s %u bytes at %d\n", > SVCFH_fmt(&argp->fh), > @@ -258,7 +259,7 @@ nfsd_proc_write(struct svc_rqst *rqstp) > > fh_copy(&resp->fh, &argp->fh); > resp->status = nfsd_write(rqstp, &resp->fh, argp->offset, > - &argp->payload, &cnt, NFS_DATA_SYNC, NULL); > + &argp->payload, &cnt, &committed, NULL); > if (resp->status == nfs_ok) > resp->status = fh_getattr(&resp->fh, &resp->stat); > else if (resp->status == nfserr_jukebox) > diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c > index f537a7b4ee01..8b2dc7a88aab 100644 > --- a/fs/nfsd/vfs.c > +++ b/fs/nfsd/vfs.c > @@ -1262,7 +1262,7 @@ static int wait_for_concurrent_writes(struct file *file) > * @offset: Byte offset of start > * @payload: xdr_buf containing the write payload > * @cnt: IN: number of bytes to write, OUT: number of bytes actually written > - * @stable: An NFS stable_how value > + * @stable_how: IN: Client's requested stable_how, OUT: Actual stable_how > * @verf: NFS WRITE verifier > * > * Upon return, caller must invoke fh_put on @fhp. > @@ -1274,11 +1274,12 @@ __be32 > nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, > struct nfsd_file *nf, loff_t offset, > const struct xdr_buf *payload, unsigned long *cnt, > - int stable, __be32 *verf) > + u32 *stable_how, __be32 *verf) > { > struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id); > struct file *file = nf->nf_file; > struct super_block *sb = file_inode(file)->i_sb; > + u32 stable = *stable_how; > struct kiocb kiocb; > struct svc_export *exp; > struct iov_iter iter; Seems we need this instead here? diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c index 5e5e5187d2e5..d0c89f8fdb57 100644 --- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -1479,7 +1479,7 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id); struct file *file = nf->nf_file; struct super_block *sb = file_inode(file)->i_sb; - u32 stable = *stable_how; + u32 stable; struct kiocb kiocb; struct svc_export *exp; errseq_t since; @@ -1511,7 +1511,8 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, exp = fhp->fh_export; if (!EX_ISSYNC(exp)) - stable = NFS_UNSTABLE; + *stable_how = NFS_UNSTABLE; + stable = *stable_how; init_sync_kiocb(&kiocb, file); kiocb.ki_pos = offset; if (stable && !fhp->fh_use_wgather) Otherwise, isn't there potential for nfsd_vfs_write's NFS_UNSTABLE override to cause a client set stable_how, that was set to something other than NFS_UNSTABLE, to silently _not_ be respected by NFSD? But client could assume COMMIT not needed? And does this then elevate this patch to be a stable@ fix? (no pun intended). If not, please help me understand why. Thanks! > @@ -1434,7 +1435,7 @@ __be32 nfsd_read(struct svc_rqst *rqstp, struct svc_fh *fhp, > * @offset: Byte offset of start > * @payload: xdr_buf containing the write payload > * @cnt: IN: number of bytes to write, OUT: number of bytes actually written > - * @stable: An NFS stable_how value > + * @stable_how: IN: Client's requested stable_how, OUT: Actual stable_how > * @verf: NFS WRITE verifier > * > * Upon return, caller must invoke fh_put on @fhp. > @@ -1444,7 +1445,7 @@ __be32 nfsd_read(struct svc_rqst *rqstp, struct svc_fh *fhp, > */ > __be32 > nfsd_write(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t offset, > - const struct xdr_buf *payload, unsigned long *cnt, int stable, > + const struct xdr_buf *payload, unsigned long *cnt, u32 *stable_how, > __be32 *verf) > { > struct nfsd_file *nf; > @@ -1457,7 +1458,7 @@ nfsd_write(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t offset, > goto out; > > err = nfsd_vfs_write(rqstp, fhp, nf, offset, payload, cnt, > - stable, verf); > + stable_how, verf); > nfsd_file_put(nf); > out: > trace_nfsd_write_done(rqstp, fhp, offset, *cnt); > diff --git a/fs/nfsd/vfs.h b/fs/nfsd/vfs.h > index fa46f8b5f132..c713ed0b04e0 100644 > --- a/fs/nfsd/vfs.h > +++ b/fs/nfsd/vfs.h > @@ -130,11 +130,13 @@ __be32 nfsd_read(struct svc_rqst *rqstp, struct svc_fh *fhp, > u32 *eof); > __be32 nfsd_write(struct svc_rqst *rqstp, struct svc_fh *fhp, > loff_t offset, const struct xdr_buf *payload, > - unsigned long *cnt, int stable, __be32 *verf); > + unsigned long *cnt, u32 *stable_how, > + __be32 *verf); > __be32 nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, > struct nfsd_file *nf, loff_t offset, > const struct xdr_buf *payload, > - unsigned long *cnt, int stable, __be32 *verf); > + unsigned long *cnt, u32 *stable_how, > + __be32 *verf); > __be32 nfsd_readlink(struct svc_rqst *, struct svc_fh *, > char *, int *); > __be32 nfsd_symlink(struct svc_rqst *, struct svc_fh *, > diff --git a/fs/nfsd/xdr3.h b/fs/nfsd/xdr3.h > index 522067b7fd75..c0e443ef3a6b 100644 > --- a/fs/nfsd/xdr3.h > +++ b/fs/nfsd/xdr3.h > @@ -152,7 +152,7 @@ struct nfsd3_writeres { > __be32 status; > struct svc_fh fh; > unsigned long count; > - int committed; > + u32 committed; > __be32 verf[2]; > }; > > -- > 2.51.0 >