From patchwork Thu Jul 20 18:13:05 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jens Axboe X-Patchwork-Id: 13320964 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 0E61EC04E69 for ; Thu, 20 Jul 2023 18:13:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230526AbjGTSNV (ORCPT ); Thu, 20 Jul 2023 14:13:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53042 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229887AbjGTSNU (ORCPT ); Thu, 20 Jul 2023 14:13:20 -0400 Received: from mail-il1-x12b.google.com (mail-il1-x12b.google.com [IPv6:2607:f8b0:4864:20::12b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5378BFC for ; Thu, 20 Jul 2023 11:13:19 -0700 (PDT) Received: by mail-il1-x12b.google.com with SMTP id e9e14a558f8ab-34637e55d9dso1179055ab.1 for ; Thu, 20 Jul 2023 11:13:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20221208.gappssmtp.com; s=20221208; t=1689876798; x=1690481598; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=lO/y0JczduNfKF+qr7m+WoYz7I0WlwYaSUZRVfc+zV4=; b=Pu/zmaJZ90qixup8NFEiStAk1UF0+44ZzF3j0OatYBtmtF3Gy4E0O+Dj2c2tEZkiem oNjk/U4ulEDcKKOVfsRpe7QvqLeQp2s/gMbZCUBK2yR2DFYnrtOTFxH4rZipRCRyPoii uY8TVDqC7Oix7O441rOzuJUU+WfZ+j/l4oI3msU2Dq2PMU5uqJfX2tKtdQ6FUPOADp6I QQESLDkScyP48b+XwLJgO1fz04/S6J/fzGXaygiN17dnm4zsYbdtjvTee9nosFmcV0QV WJB6iyJC2QRnSUvFl9ZjzceIVXB+oO4ysU/LGDKKOs8E8K1lePgmvNrMLzmIWGgkcqnh c0rw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1689876798; x=1690481598; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=lO/y0JczduNfKF+qr7m+WoYz7I0WlwYaSUZRVfc+zV4=; b=XvDSF2MhuoJjzprH4tOUR60mJlYgqutiNAq+euuRjcQ53Eri/E7jsukFNa8WJxa+4W c2n3WpLKFd51hbfzJ1efOS3DnUHKzM8ARcITQdaNAXl8jU5v8j+CjGLJotMMGQbN8wCO 5zXQ4FtMiWIRI001SM5yZ5gWOiDzN7TLno8ddWhwOOf20ESp7Y3hZd1QQgOVdZz5GdP+ 3S38Mw7J5VQGkF00R3OD7NyvfyebkmmE0alxvly8jGgniVEjkIX8YD0baoaAyVAcGcJV 0itaIulQQAbE55N/NfbapN5TEwK2szhNCw1KebWnrqmlQtimz2epvdcWWA7bE4oL/2uk q3Ww== X-Gm-Message-State: ABy/qLYkokrkXIelsbA835Va81opWexG56SxoaW367sFCkNCmXclk51v zBvCNA6lSmf8ViBcfggaYZpjlg== X-Google-Smtp-Source: APBJJlE7fUZUWzIAkTh5EVdAECs4Ej9tOOcP9r7khn+zVkqb+CMEgaCM9pBkodR5d/h/5QA0K7QCcg== X-Received: by 2002:a05:6e02:17c8:b0:346:4eb9:9081 with SMTP id z8-20020a056e0217c800b003464eb99081mr12451755ilu.3.1689876798649; Thu, 20 Jul 2023 11:13:18 -0700 (PDT) Received: from localhost.localdomain ([96.43.243.2]) by smtp.gmail.com with ESMTPSA id v6-20020a92c6c6000000b003457e1daba8sm419171ilm.8.2023.07.20.11.13.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 20 Jul 2023 11:13:17 -0700 (PDT) From: Jens Axboe To: io-uring@vger.kernel.org, linux-xfs@vger.kernel.org Cc: hch@lst.de, andres@anarazel.de, david@fromorbit.com, Jens Axboe Subject: [PATCH 3/8] iomap: treat a write through cache the same as FUA Date: Thu, 20 Jul 2023 12:13:05 -0600 Message-Id: <20230720181310.71589-4-axboe@kernel.dk> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230720181310.71589-1-axboe@kernel.dk> References: <20230720181310.71589-1-axboe@kernel.dk> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org Whether we have a write back cache and are using FUA or don't have a write back cache at all is the same situation. Treat them the same. This makes the IOMAP_DIO_WRITE_FUA name a bit misleading, as we have two cases that provide stable writes: 1) Volatile write cache with FUA writes 2) Normal write without a volatile write cache Rename that flag to IOMAP_DIO_STABLE_WRITE to make that clearer, and update some of the FUA comments as well. Signed-off-by: Jens Axboe Reviewed-by: Christoph Hellwig Reviewed-by: Darrick J. Wong --- fs/iomap/direct-io.c | 29 +++++++++++++++++------------ 1 file changed, 17 insertions(+), 12 deletions(-) diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c index c654612b24e5..9f97d0d03724 100644 --- a/fs/iomap/direct-io.c +++ b/fs/iomap/direct-io.c @@ -21,7 +21,7 @@ * iomap.h: */ #define IOMAP_DIO_INLINE_COMP (1 << 27) -#define IOMAP_DIO_WRITE_FUA (1 << 28) +#define IOMAP_DIO_STABLE_WRITE (1 << 28) #define IOMAP_DIO_NEED_SYNC (1 << 29) #define IOMAP_DIO_WRITE (1 << 30) #define IOMAP_DIO_DIRTY (1 << 31) @@ -222,7 +222,7 @@ static void iomap_dio_zero(const struct iomap_iter *iter, struct iomap_dio *dio, /* * Figure out the bio's operation flags from the dio request, the * mapping, and whether or not we want FUA. Note that we can end up - * clearing the WRITE_FUA flag in the dio request. + * clearing the STABLE_WRITE flag in the dio request. */ static inline blk_opf_t iomap_dio_bio_opflags(struct iomap_dio *dio, const struct iomap *iomap, bool use_fua) @@ -236,7 +236,7 @@ static inline blk_opf_t iomap_dio_bio_opflags(struct iomap_dio *dio, if (use_fua) opflags |= REQ_FUA; else - dio->flags &= ~IOMAP_DIO_WRITE_FUA; + dio->flags &= ~IOMAP_DIO_STABLE_WRITE; return opflags; } @@ -276,11 +276,13 @@ static loff_t iomap_dio_bio_iter(const struct iomap_iter *iter, * Use a FUA write if we need datasync semantics, this is a pure * data IO that doesn't require any metadata updates (including * after IO completion such as unwritten extent conversion) and - * the underlying device supports FUA. This allows us to avoid - * cache flushes on IO completion. + * the underlying device either supports FUA or doesn't have + * a volatile write cache. This allows us to avoid cache flushes + * on IO completion. */ if (!(iomap->flags & (IOMAP_F_SHARED|IOMAP_F_DIRTY)) && - (dio->flags & IOMAP_DIO_WRITE_FUA) && bdev_fua(iomap->bdev)) + (dio->flags & IOMAP_DIO_STABLE_WRITE) && + (bdev_fua(iomap->bdev) || !bdev_write_cache(iomap->bdev))) use_fua = true; } @@ -560,12 +562,15 @@ __iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, /* * 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. + * using STABLE_WRITE for this IO. Stable writes are + * either FUA with a write cache, or a normal write to + * a device without a volatile write cache. For the + * former, 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; + dio->flags |= IOMAP_DIO_STABLE_WRITE; } /* @@ -627,10 +632,10 @@ __iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, iomap_dio_set_error(dio, ret); /* - * If all the writes we issued were FUA, we don't need to flush the + * If all the writes we issued were stable, we don't need to flush the * cache on IO completion. Clear the sync flag for this case. */ - if (dio->flags & IOMAP_DIO_WRITE_FUA) + if (dio->flags & IOMAP_DIO_STABLE_WRITE) dio->flags &= ~IOMAP_DIO_NEED_SYNC; WRITE_ONCE(iocb->private, dio->submit.poll_bio);