From patchwork Fri Aug 27 16:49:22 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andreas Gruenbacher X-Patchwork-Id: 12462395 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1ACB4C4320E for ; Fri, 27 Aug 2021 16:51:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 017B860FE6 for ; Fri, 27 Aug 2021 16:51:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239005AbhH0QwM (ORCPT ); Fri, 27 Aug 2021 12:52:12 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:34362 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237886AbhH0QwD (ORCPT ); Fri, 27 Aug 2021 12:52:03 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1630083074; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=rEdh4JFLYRsuZzefqrc2GRJpUnyWETbVekgWWtQoVm4=; b=Y1aLIJr1bxWUXd0PWgbqC9L3iZviwZHmJBjb4iXsJoWEFzZ6O/SO+lBLcijw1yZn01GNlR fVUDSdcZyqkPqpJwwMLLLA8BzoCDYgj2SPhep91fSy1ANQY+tzs5RZP1ARaCGYOF9kGPAH Q/1CRQImMApRLQPdEbRdyox2o8f7IKs= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-187-iO0WxY7EPbKr5p4Fj3Bdmg-1; Fri, 27 Aug 2021 12:51:12 -0400 X-MC-Unique: iO0WxY7EPbKr5p4Fj3Bdmg-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 2B9368799EE; Fri, 27 Aug 2021 16:51:11 +0000 (UTC) Received: from max.com (unknown [10.40.194.206]) by smtp.corp.redhat.com (Postfix) with ESMTP id B0BB460C81; Fri, 27 Aug 2021 16:51:08 +0000 (UTC) From: Andreas Gruenbacher To: Linus Torvalds , Alexander Viro , Christoph Hellwig , "Darrick J. Wong" Cc: Jan Kara , Matthew Wilcox , cluster-devel@redhat.com, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, ocfs2-devel@oss.oracle.com, Andreas Gruenbacher Subject: [PATCH v7 15/19] iomap: Support partial direct I/O on user copy failures Date: Fri, 27 Aug 2021 18:49:22 +0200 Message-Id: <20210827164926.1726765-16-agruenba@redhat.com> In-Reply-To: <20210827164926.1726765-1-agruenba@redhat.com> References: <20210827164926.1726765-1-agruenba@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org In iomap_dio_rw, when iomap_apply returns an -EFAULT error and the IOMAP_DIO_PARTIAL flag is set, complete the request synchronously and return a partial result. This allows the caller to deal with the page fault and retry the remainder of the request. Signed-off-by: Andreas Gruenbacher Reviewed-by: Darrick J. Wong --- fs/iomap/direct-io.c | 6 ++++++ include/linux/iomap.h | 7 +++++++ 2 files changed, 13 insertions(+) diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c index 8054f5d6c273..ba88fe51b77a 100644 --- a/fs/iomap/direct-io.c +++ b/fs/iomap/direct-io.c @@ -561,6 +561,12 @@ __iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, ret = iomap_apply(inode, pos, count, iomap_flags, ops, dio, iomap_dio_actor); if (ret <= 0) { + if (ret == -EFAULT && dio->size && + (dio_flags & IOMAP_DIO_PARTIAL)) { + wait_for_completion = true; + ret = 0; + } + /* magic error code to fall back to buffered I/O */ if (ret == -ENOTBLK) { wait_for_completion = true; diff --git a/include/linux/iomap.h b/include/linux/iomap.h index 479c1da3e221..bcae4814b8e3 100644 --- a/include/linux/iomap.h +++ b/include/linux/iomap.h @@ -267,6 +267,13 @@ struct iomap_dio_ops { */ #define IOMAP_DIO_OVERWRITE_ONLY (1 << 1) +/* + * When a page fault occurs, return a partial synchronous result and allow + * the caller to retry the rest of the operation after dealing with the page + * fault. + */ +#define IOMAP_DIO_PARTIAL (1 << 2) + ssize_t iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, const struct iomap_ops *ops, const struct iomap_dio_ops *dops, unsigned int dio_flags);