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 F33DB4C74; Tue, 24 Jun 2025 18:26:21 +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=1750789582; cv=none; b=WiTnri1ONt73frCnh9UfxFrJsKk3A2ckXD/S9ATXkrnR7DX0oeQjwhZa4qEGddHI0Q8OSVb+L83zHXUjJFUsnJsj2Mf6ohb9N9Kho2JHhsm2oEA3/XCrMbk17iYzG7tj6qrIa25gQxZhb5P4uLe/dpSrYpuaK3AWFuGFfwVgGJU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750789582; c=relaxed/simple; bh=SjqIBmL97gLe/mWNOgIQYeXsvTY1JW6Zg34BKOfyvOA=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=NTONtvNh2OyevrT8Nx7kP/abUlxBt4As0keyDTad9heo834OWlpOZFN2kKmJsL7bqAcff2XdOEqfl9Oe+t3n3Di2eBmmY254kxhPvOT5MFblg+0+ERWin7rg+v/G7ffkq2Vwft9d2Wwb5Z9Twoc+GiIs08LmG3BXwVjgQe+8guE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=CbHyxhV9; 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="CbHyxhV9" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B4A7BC4CEE3; Tue, 24 Jun 2025 18:26:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1750789581; bh=SjqIBmL97gLe/mWNOgIQYeXsvTY1JW6Zg34BKOfyvOA=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=CbHyxhV9cgmQikJFxVH5EDQu+xu1qzoutmwlfPqBVlYjdHmZSD/jVfbmk31frMdLr DQFtGST4aWDA688gTKIwAsizNjZIySRomClbDr5W6iqRMnUnWPysdG5QtyXM0CvlOv jQ0eUyXOSUXwhxWvJ7Qcd/LLU9kAkIm42e/M25LG5xnSmGA1/BvqbZm1NCoCD0O7b6 q4aBBcbl1e8X4Uu6bEhgiFnF36fdpAJeMIzDwFNtBUiocc6vQg9wbZVzSM/BhvA1n9 L0u7Bf34oEdeuntAcbpaXrv7Ay6CCGPGWmMk3qX+RB0qgAFehA2esxuHs7V6ALnzvG CovHn1MDWF2vw== Message-ID: Subject: Re: [PATCH] xfs: report a writeback error on a read() call From: Jeff Layton To: Christoph Hellwig , ying chen Cc: djwong@kernel.org, linux-xfs@vger.kernel.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Date: Tue, 24 Jun 2025 14:26:18 -0400 In-Reply-To: References: Autocrypt: addr=jlayton@kernel.org; prefer-encrypt=mutual; keydata=mQINBE6V0TwBEADXhJg7s8wFDwBMEvn0qyhAnzFLTOCHooMZyx7XO7dAiIhDSi7G1NPxw n8jdFUQMCR/GlpozMFlSFiZXiObE7sef9rTtM68ukUyZM4pJ9l0KjQNgDJ6Fr342Htkjxu/kFV1Wv egyjnSsFt7EGoDjdKqr1TS9syJYFjagYtvWk/UfHlW09X+jOh4vYtfX7iYSx/NfqV3W1D7EDi0PqV T2h6v8i8YqsATFPwO4nuiTmL6I40ZofxVd+9wdRI4Db8yUNA4ZSP2nqLcLtFjClYRBoJvRWvsv4lm 0OX6MYPtv76hka8lW4mnRmZqqx3UtfHX/hF/zH24Gj7A6sYKYLCU3YrI2Ogiu7/ksKcl7goQjpvtV YrOOI5VGLHge0awt7bhMCTM9KAfPc+xL/ZxAMVWd3NCk5SamL2cE99UWgtvNOIYU8m6EjTLhsj8sn 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However, if an error occurs during the actual disk > > write operation, data loss may ensue, and there is no way to report > > this error back to user space immediately. Current kernels may report > > writeback errors when fsync() is called, but frequent invocations of > > fsync() can degrade performance. Therefore, a new sysctl > > fs.xfs.report_writeback_error_on_read is introduced, which, when set > > to 1, reports writeback errors when read() is called. This allows user > > space to be notified of writeback errors more promptly. >=20 > That's really kernel wide policy and not something magic done by a > single file system. ...not to mention that getting an error back on a read for a prior writeback error would be completely unexpected by most applications. --=20 Jeff Layton