From nobody Mon Nov 25 04:26:16 2024 Received: from mail-pg1-f169.google.com (mail-pg1-f169.google.com [209.85.215.169]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D37BF2144A9; Wed, 30 Oct 2024 15:58:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.169 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730303905; cv=none; b=grvpFR5Utd67y2zZQ7hGLDXVsBpotRHpz/X8sMuq/KXbE7elSeoobZdQn1C3/VbhY6NcGBDZwo1K0NLtjO/lFeDlWTz+2t/J9fVpXACwKO3NmAu79Gb2s421UERzaBqzKfLJmkUP+EvVHmlAz2QBRpKm6yPnO2Ch38iw4wXEqXw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730303905; c=relaxed/simple; bh=LzN5+Qpd7fuL14+fAVQDSNU6E/uPPJd4jhyHUUHdrXE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=uHWh66QC85zZh5Qbt331lRrsKhhHgw6CtTdH8uEDf9fuUbpm7rDYGX/c9wR21ECSLIMvP3F7b2UZdpjxgcg+2/UADVhKtYFTJfP/4F9HbCptkFgvriat2qg/LtnabNI1syf9lwg6ozdqQN5XSUP3piv8uH0cOJ3bYgnpsDq7j/Q= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=jgFyGQfQ; arc=none smtp.client-ip=209.85.215.169 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="jgFyGQfQ" Received: by mail-pg1-f169.google.com with SMTP id 41be03b00d2f7-7ea6a4f287bso31057a12.3; Wed, 30 Oct 2024 08:58:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1730303903; x=1730908703; darn=vger.kernel.org; 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=pGqbYAHXK4Jd6LmiaTB3lDHwM2K50OqruyDt1hmpDOc=; b=jgFyGQfQuNT3bYW3Rj1ew3UOSOKYaaVW9yBIyAH+FR1gDRZdyvMvj3i7pkRLqgmlbK +odCCjVEdzhdTLNP3Ycl0jyZRyJe2NrOgI8L1b1m/u0Dq1R0YYxzlMwktkVpTQtCfutc eaVHnu8EKvVGFrR4l2SyOLl0rnJDzTErMkJsJGpSi68mUb4iFfuGvunylR/HO9OiGSbk hThFewh3iT3W7fHpKd30kQVsw53Vwj6GhKetTAv4hrwPm3BcFQwatVdWh15LfPppQ8O5 Wqf1IW93w3EijoGhl13ZT4NMtOY19GbtGopPGlNMoLtekoUsMCUzSw8fY4phbnGlqpml 2VHw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1730303903; x=1730908703; 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=pGqbYAHXK4Jd6LmiaTB3lDHwM2K50OqruyDt1hmpDOc=; b=su7FjUi6MSnXcd+N2Hz9eLjiFKi376WH4RxRaAgNkpjim6GrrPcDPYvNrULl69mbWY u1L+DsOc04bUcNVYwUhuBY8AkvPFgJMBxnsA9WZdjwvT7tdHJLXpXpg3lojqoYr69Nx0 68TPaVPXTtjtx4QAeuhlLc545Ma02UZWUYOhAKal1JHDkzdwx5bQacDMoDBwTJBAOmFb LK/aEgllqkBGJQvuF3+mfOftPQ/4V4NYU4/yn7DZAkGEjxHLedy1NzRDZ57nfiBt/2py FP3w+8esqT7DWuqnSvQzb1K2NLj/E8djv6uHHOZdSKa1j2K3zw2k4mkRDCXBoxZbk6NH VawA== X-Forwarded-Encrypted: i=1; AJvYcCViTmr0ApLpfZvuwrXxYcBBBZPjdU3bA2vmtOmsVEwa8fwwmIwMm19tXufUdZ1oVN0528h1ryuy172basSj@vger.kernel.org, AJvYcCWIVN9hp6eXz9YYvHMO119/R7g83LiVZCKv5rLxs/v7RTCiZrCIFIHg1Y5LHlYENaWj4qPuq2Br791R@vger.kernel.org, AJvYcCXIxx5h4MQgToiK+xn2FgzcOtE5t/rnP8x/buhpjoZe5S5DpqKtao217Erq4ILNQjyuWRd4B9HUqrZejMaX@vger.kernel.org X-Gm-Message-State: AOJu0Ywpa4NVrMWm8DWGpvqIDqlnzRq/RxmWKNkQLDmN++6NNvTDh0nu ifJt6mp2hh1IApmfC/lVU//EW/37M+fYnDKz5MqaYV314yYGq3WD/CCQDA== X-Google-Smtp-Source: AGHT+IERpMAKdiB7Q+yEULyTmcaK7Y2OEMDYKNAg4w67ROuwPqoJMrUWG93TXtbM1zJgoABdgJmOjQ== X-Received: by 2002:a05:6a20:d528:b0:1d9:f95:9f97 with SMTP id adf61e73a8af0-1d9a83c22b1mr19163886637.16.1730303902714; Wed, 30 Oct 2024 08:58:22 -0700 (PDT) Received: from dw-tp.ibmuc.com ([203.81.241.194]) by smtp.gmail.com with ESMTPSA id 41be03b00d2f7-7edc89f2d5bsm9407519a12.57.2024.10.30.08.58.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 30 Oct 2024 08:58:22 -0700 (PDT) From: "Ritesh Harjani (IBM)" To: linux-ext4@vger.kernel.org Cc: Theodore Ts'o , Jan Kara , "Darrick J . Wong" , Christoph Hellwig , John Garry , Ojaswin Mujoo , Dave Chinner , linux-kernel@vger.kernel.org, linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, "Ritesh Harjani (IBM)" Subject: [PATCH v3 4/4] ext4: Do not fallback to buffered-io for DIO atomic write Date: Wed, 30 Oct 2024 21:27:41 +0530 Message-ID: <3c6f41ebed5ca2a669fb05ccc38e8530d0e3e220.1730286164.git.ritesh.list@gmail.com> X-Mailer: git-send-email 2.46.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" atomic writes is currently only supported for single fsblock and only for direct-io. We should not return -ENOTBLK for atomic writes since we want the atomic write request to either complete fully or fail otherwise. We should not fallback to buffered-io in case of DIO atomic write requests. Let's also catch if this ever happens by adding some WARN_ON_ONCE before buffered-io handling for direct-io atomic writes. More details of the discussion [1]. [1]: https://lore.kernel.org/linux-xfs/cover.1729825985.git.ritesh.list@gma= il.com/T/#m9dbecc11bed713ed0d7a486432c56b105b555f04 Signed-off-by: Ritesh Harjani (IBM) --- fs/ext4/file.c | 7 +++++++ fs/ext4/inode.c | 14 +++++++++----- 2 files changed, 16 insertions(+), 5 deletions(-) diff --git a/fs/ext4/file.c b/fs/ext4/file.c index 8116bd78910b..61787a37e9d4 100644 --- a/fs/ext4/file.c +++ b/fs/ext4/file.c @@ -599,6 +599,13 @@ static ssize_t ext4_dio_write_iter(struct kiocb *iocb,= struct iov_iter *from) ssize_t err; loff_t endbyte; =20 + /* + * There is no support for atomic writes on buffered-io yet, + * we should never fallback to buffered-io for DIO atomic + * writes. + */ + WARN_ON_ONCE(iocb->ki_flags & IOCB_ATOMIC); + offset =3D iocb->ki_pos; err =3D ext4_buffered_write_iter(iocb, from); if (err < 0) diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index fcdee27b9aa2..26b3c84d7f64 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -3449,12 +3449,16 @@ static int ext4_iomap_end(struct inode *inode, loff= _t offset, loff_t length, { /* * Check to see whether an error occurred while writing out the data to - * the allocated blocks. If so, return the magic error code so that we - * fallback to buffered I/O and attempt to complete the remainder of - * the I/O. Any blocks that may have been allocated in preparation for - * the direct I/O will be reused during buffered I/O. + * the allocated blocks. If so, return the magic error code for + * non-atomic write so that we fallback to buffered I/O and attempt to + * complete the remainder of the I/O. + * For atomic writes we will simply fail the I/O request if we coudn't + * write anything. For non-atomic writes, any blocks that may have been + * allocated in preparation for the direct I/O will be reused during + * buffered I/O. */ - if (flags & (IOMAP_WRITE | IOMAP_DIRECT) && written =3D=3D 0) + if (!(flags & IOMAP_ATOMIC) && (flags & (IOMAP_WRITE | IOMAP_DIRECT)) + && written =3D=3D 0) return -ENOTBLK; =20 return 0; --=20 2.46.0