From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 55E0EC43334 for ; Wed, 8 Jun 2022 00:17:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346863AbiFHARK (ORCPT ); Tue, 7 Jun 2022 20:17:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56618 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1835779AbiFGX47 (ORCPT ); Tue, 7 Jun 2022 19:56:59 -0400 Received: from zeniv-ca.linux.org.uk (zeniv-ca.linux.org.uk [IPv6:2607:5300:60:148a::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9192CFCEE2 for ; Tue, 7 Jun 2022 16:31:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=linux.org.uk; s=zeniv-20220401; h=Sender:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description; bh=/pOgsB9gQwCdomVp/dKefg8p8DNuh1uMRuVi98ZGBWc=; b=MVGI3RsZ0MB4sHgt1sZxh04NPH B+gPWTE367oaxDQopMVe59SIeeLQJhYp1eAqS5UAtBGbiEuxPkCmdgO0Z7I36wFr/aSYi08Bb8q6V GIsvjPmbwOhdRmBBt3RoGUbLc6m9AyqQt84SAED7OuJT5fLpbY0CkwKX6QReVc0PnqLFiuJOH2ihl mSRAdNPL+V0HOAXlz0Rp30Ye0GjAUZedNJJpn6P6jrJAAno6xc84e8oewpj2b5ZONEYE22ZbhGUpW 3cXy/ymc/MgznH/out0ZrDImvFNUtDmEMhWvrbKCYKD+JMYhmQBAHWq1moYrZhAIGmUcPAvpsO6sX Cvw8eG6A==; Received: from viro by zeniv-ca.linux.org.uk with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1nyifn-004ttH-L8; Tue, 07 Jun 2022 23:31:43 +0000 From: Al Viro To: linux-fsdevel@vger.kernel.org Cc: Christoph Hellwig , Jens Axboe , Matthew Wilcox Subject: [PATCH 02/10] teach iomap_dio_rw() to suppress dsync Date: Tue, 7 Jun 2022 23:31:35 +0000 Message-Id: <20220607233143.1168114-2-viro@zeniv.linux.org.uk> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20220607233143.1168114-1-viro@zeniv.linux.org.uk> References: <20220607233143.1168114-1-viro@zeniv.linux.org.uk> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: Al Viro Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org New flag, equivalent to removal of IOCB_DSYNC from iocb flags. This mimics what btrfs is doing (and that's what btrfs will switch to). However, I'm not at all sure that we want to suppress REQ_FUA for those - all btrfs hack really cares about is suppression of generic_write_sync(). For now let's keep the existing behaviour, but I really want to hear more detailed arguments pro or contra. [folded brain fix from willy] Suggested-by: Christoph Hellwig Signed-off-by: Al Viro --- fs/iomap/direct-io.c | 20 +++++++++++--------- include/linux/iomap.h | 6 ++++++ 2 files changed, 17 insertions(+), 9 deletions(-) diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c index 370c3241618a..c10c69e2de24 100644 --- a/fs/iomap/direct-io.c +++ b/fs/iomap/direct-io.c @@ -548,17 +548,19 @@ __iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, } /* for data sync or sync, we need sync completion processing */ - if (iocb->ki_flags & IOCB_DSYNC) + if (iocb->ki_flags & IOCB_DSYNC && + !(dio_flags & IOMAP_DIO_NOSYNC)) { dio->flags |= IOMAP_DIO_NEED_SYNC; - /* - * For datasync only writes, we optimistically try using FUA for - * this IO. Any non-FUA write that occurs will clear this flag, - * hence we know before completion whether a cache flush is - * necessary. - */ - if ((iocb->ki_flags & (IOCB_DSYNC | IOCB_SYNC)) == IOCB_DSYNC) - dio->flags |= IOMAP_DIO_WRITE_FUA; + /* + * For datasync only writes, we optimistically try + * using FUA for this IO. Any non-FUA write that + * occurs will clear this flag, hence we know before + * completion whether a cache flush is necessary. + */ + if (!(iocb->ki_flags & IOCB_SYNC)) + dio->flags |= IOMAP_DIO_WRITE_FUA; + } } if (dio_flags & IOMAP_DIO_OVERWRITE_ONLY) { diff --git a/include/linux/iomap.h b/include/linux/iomap.h index e552097c67e0..c8622d8f064e 100644 --- a/include/linux/iomap.h +++ b/include/linux/iomap.h @@ -353,6 +353,12 @@ struct iomap_dio_ops { */ #define IOMAP_DIO_PARTIAL (1 << 2) +/* + * The caller will sync the write if needed; do not sync it within + * iomap_dio_rw. Overrides IOMAP_DIO_FORCE_WAIT. + */ +#define IOMAP_DIO_NOSYNC (1 << 3) + 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, void *private, size_t done_before); -- 2.30.2