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 6D9693164DC for ; Mon, 20 Oct 2025 13:56:04 +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=1760968565; cv=none; b=PXNAKQa6OGfvUEnTAHB9h+2EUxh+G73Y48RA5Gy/6Y0pG4MlMDkHd7jk/fEKvwWqfYw2TiS6TkTa67j4BJZT8e13+L/V8SLnUmGxpzgx1FljPFSDl1REnKYSiKx26uxJQFrRp7s/2W9GhzZUT6/B9QkAfaAuTkU2MIjOPjMQkN8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760968565; c=relaxed/simple; bh=Q3utQyW/9W64IGo8ZE/0OLSZpMpSjhH6ayaNzEI8yNc=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=q8mY2kOyxmgglkOD168rhWGj9miJisB3KlS4/KEsbnahEZ6JQlcjXP+jzn9WxrYP4LrspDqDJEfbsmdMk9B5nFg/PFUzakClK5imXqOMbBPjsPkG56A4+XO5UAB29zHwNZEXG96W7TnQSbuLkaHe+/kv2Tuq9ryzrXYOpNFjzio= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Qk2j/2KV; 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="Qk2j/2KV" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3DE86C113D0; Mon, 20 Oct 2025 13:56:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1760968563; bh=Q3utQyW/9W64IGo8ZE/0OLSZpMpSjhH6ayaNzEI8yNc=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=Qk2j/2KVHRBD1mT3rmjMUkRHFIWe0vP22FImPtHsgsX2JXyDXSv3frIwNH9b8ND1X 0Wi5+IZgAPVkiuE630FbO9QOGMjvsfGt5eecirG/RxTaSV2NkYQNRncmrYhYIl0Il3 Plz040bcCSxggGn+9oKzHmaDXlfDcFkDCXEc5h3Y6eNuSX5oPBvTNZdsx3a6diOLlc j0W4MkHbWUcmaVG/gtgoH8EVWshOXVsSXjnlQoqlFqJesQ8fjm5iYi0RZEqtxbWsw2 arbr5+ce1m5PK5fpiefOUfF3UVwo8IR+wPP8ZeGzE0m4IUC84wsoL/RiMY76A7umQP 6ol+UvvmBUBJA== Message-ID: <67e3763c-d20c-4e1c-b7ff-62b59c385210@kernel.org> Date: Mon, 20 Oct 2025 09:56:02 -0400 Precedence: bulk X-Mailing-List: linux-nfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 2/3] NFSD: Implement NFSD_IO_DIRECT for NFS WRITE To: Christoph Hellwig , Mike Snitzer Cc: NeilBrown , Jeff Layton , Olga Kornievskaia , Dai Ngo , Tom Talpey , linux-nfs@vger.kernel.org References: <20251018005431.3403-1-cel@kernel.org> <20251018005431.3403-3-cel@kernel.org> Content-Language: en-US From: Chuck Lever Organization: kernel.org In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 10/20/25 3:19 AM, Christoph Hellwig wrote: > On Fri, Oct 17, 2025 at 08:54:30PM -0400, Chuck Lever wrote: >> From: Mike Snitzer >> +static int >> +nfsd_buffered_write(struct svc_rqst *rqstp, struct file *file, >> + unsigned int nvecs, unsigned long *cnt, >> + struct kiocb *kiocb) >> +{ >> + struct iov_iter iter; >> + int host_err; >> + >> + iov_iter_bvec(&iter, ITER_SOURCE, rqstp->rq_bvec, nvecs, *cnt); >> + host_err = vfs_iocb_iter_write(file, kiocb, &iter); >> + if (host_err < 0) >> + return host_err; >> + *cnt = host_err; >> + >> + return 0; > > > Nothing really buffered here per se, it's just a small wrapper > around vfs_iocb_iter_write. This is the original NFSD_IO_BUFFERED code, refactored out of nfsd_vfs_write(). IMO it might be more clear what's going on if the refactoring was done in a separate prerequisite patch. >> + } else if (unlikely(host_err == -EINVAL)) { >> + struct inode *inode = d_inode(fhp->fh_dentry); >> + >> + pr_info_ratelimited("nfsd: Direct I/O alignment failure on %s/%ld\n", >> + inode->i_sb->s_id, inode->i_ino); >> + host_err = -ESERVERFAULT; > > -EINVAL can be lot more things than alignment failure. And more > importantly alignment failures should not happen with the proper > checks in place. I tend to agree that I expect an alignment failure will rarely if ever happen if we've done our job well. -- Chuck Lever