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 C4A4531280B for ; Mon, 27 Oct 2025 15:46:44 +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=1761580004; cv=none; b=gvKIPfP9ZgSC/PZGt9kYoQ63PSsuQ741q+PNUncsCh4MTdl4rIBoTUr/YkFfPRrBeQKecKxnBgPU4Vxr3hu1pBTnv+g+R5vzYqA8PNPS8HWjY+MWlsTSZoAVeGbSrnnCLrLdc9cZgAMW64e4l02vOOoYU6eIDGTC39R4wYNT6V0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761580004; c=relaxed/simple; bh=F00EZcyONm2bTtHF5bQQSpRQjMCQhruwVjHWUjRh1Gk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=S9min7hkYxvzTPrtFFmoP2gyHei6DkmCDX19c39nv2dyMOR3DWYpnUo5EUkbZxE8uGFEK3wn2u23TKy0deiwvxNZVjoGjf8A3O0RFoFGL4cnayBd9hQFiDAz/s/DkgGRUb5W9+orS04kMTcXuvi37KnpJJA3NZCX+n9EQsZmPcU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=eAHyjrDZ; 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="eAHyjrDZ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B492FC4CEFF; Mon, 27 Oct 2025 15:46:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1761580004; bh=F00EZcyONm2bTtHF5bQQSpRQjMCQhruwVjHWUjRh1Gk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=eAHyjrDZTwId0tEAQRireG+NgqFvCIgmizFroyQZ/125l/FCeGlXvK2CbY87dkiJz CanxPzvaD+YwVsRIepMAMBt6iIhHFi2RHVQoHRrvfV4n0nHAJdkuWUF7VHFhMrapq4 /LbOdrrFdByD1o0T4aRiXAw0wlm4Z9aXljTB4CaYHh5b2lcgduRhcrl2ThuzGwDpDG 4M+CSzbv8BWtpDrMqYAKc/yvj/2DlaVRVBs6gH3zxqStW1gEUfjDZsEcbRg7FiBw5K 36QzgB3Anyp5rXAbaoJTj05RLRWc3pgSDtkXalckBOkmPCwo0jgErpicrZM3jv35SF CK+uwKNIvnS+Q== From: Chuck Lever To: NeilBrown , Jeff Layton , Olga Kornievskaia , Dai Ngo , Tom Talpey Cc: , Christoph Hellwig , Chuck Lever Subject: [PATCH v8 11/12] NFSD: Handle kiocb->ki_flags correctly Date: Mon, 27 Oct 2025 11:46:29 -0400 Message-ID: <20251027154630.1774-12-cel@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20251027154630.1774-1-cel@kernel.org> References: <20251027154630.1774-1-cel@kernel.org> Precedence: bulk X-Mailing-List: linux-nfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Chuck Lever Christoph says: > > + if (file->f_op->fop_flags & FOP_DONTCACHE) > > + kiocb->ki_flags |= IOCB_DONTCACHE; > IOCB_DONTCACHE isn't defined for IOCB_DIRECT. So this should > move into a branch just for buffered I/O. and > > Promoting all NFSD_IO_DIRECT writes to FILE_SYNC was my idea, > > based on the assumption that IOCB_DIRECT writes to local file > > systems left nothing to be done by a later commit. My assumption > > is based on the behavior of O_DIRECT on NFS files. > > > > If that assumption is not true, then I agree there is no > > technical reason to promote NFSD_IO_DIRECT writes to FILE_SYNC, > > and I can remove that built-in assumption for v8 of this series. > > It is not true, or rather only true for a tiny subset of use cases > (which NFS can't even query a head of time). So, observe the existing setting of ki_flags rather than forcing persistence unconditionally, and ensure that DONTCACHE is not set for IOCB_DIRECT writes. Suggested-by: Christoph Hellwig Signed-off-by: Chuck Lever --- fs/nfsd/vfs.c | 33 ++++++++++++++------------------- 1 file changed, 14 insertions(+), 19 deletions(-) diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c index be0688f2ab3d..3c78b3aeea4b 100644 --- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -1261,6 +1261,8 @@ struct nfsd_write_dio_seg { struct nfsd_write_dio_args { struct nfsd_file *nf; + int flags_buffered; + int flags_direct; unsigned int nsegs; struct nfsd_write_dio_seg segment[3]; }; @@ -1396,33 +1398,25 @@ nfsd_buffered_write(struct svc_rqst *rqstp, struct file *file, } static int -nfsd_issue_dio_write(struct svc_rqst *rqstp, struct svc_fh *fhp, u32 *stable_how, - struct kiocb *kiocb, unsigned int nvecs, unsigned long *cnt, - struct nfsd_write_dio_args *args) +nfsd_issue_dio_write(struct svc_rqst *rqstp, struct svc_fh *fhp, + struct kiocb *kiocb, unsigned int nvecs, + unsigned long *cnt, struct nfsd_write_dio_args *args) { struct file *file = args->nf->nf_file; ssize_t host_err; unsigned int i; - /* - * Any buffered IO issued here will be misaligned, use - * sync IO to ensure it has completed before returning. - * Also update @stable_how to avoid need for COMMIT. - */ - kiocb->ki_flags |= (IOCB_DSYNC|IOCB_SYNC); - *stable_how = NFS_FILE_SYNC; - nfsd_write_dio_iters_init(rqstp->rq_bvec, nvecs, kiocb->ki_pos, *cnt, args); *cnt = 0; for (i = 0; i < args->nsegs; i++) { if (args->segment[i].use_dio) { - kiocb->ki_flags |= IOCB_DIRECT; + kiocb->ki_flags = args->flags_direct; trace_nfsd_write_direct(rqstp, fhp, kiocb->ki_pos, args->segment[i].iter.count); } else - kiocb->ki_flags &= ~IOCB_DIRECT; + kiocb->ki_flags = args->flags_buffered; host_err = vfs_iocb_iter_write(file, kiocb, &args->segment[i].iter); @@ -1446,15 +1440,16 @@ nfsd_direct_write(struct svc_rqst *rqstp, struct svc_fh *fhp, args.nf = nf; /* - * Check if IOCB_DONTCACHE can be used when issuing buffered IO; - * if so, set it to preserve intent of NFSD_IO_DIRECT (it will - * be ignored for any DIO issued here). + * IOCB_DONTCACHE preserves the intent of NFSD_IO_DIRECT when + * writing unaligned segments or handling fallback I/O. */ + args.flags_buffered = kiocb->ki_flags; if (args.nf->nf_file->f_op->fop_flags & FOP_DONTCACHE) - kiocb->ki_flags |= IOCB_DONTCACHE; + args.flags_buffered |= IOCB_DONTCACHE; - return nfsd_issue_dio_write(rqstp, fhp, stable_how, kiocb, nvecs, - cnt, &args); + args.flags_direct = kiocb->ki_flags | IOCB_DIRECT; + + return nfsd_issue_dio_write(rqstp, fhp, kiocb, nvecs, cnt, &args); } /** -- 2.51.0