From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 03C6C1428E7; Wed, 5 Mar 2025 01:34:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.133 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741138473; cv=none; b=VWLfVAh/lh/u8VZ6KgpkcS+BZDZFqwIqzaseq75+sO4PpFR1iTI1sdcqT7FvbsmJ1omgZPPzUsLQbc32t8bBmGbmfdJGXZCHgzu2Q6fkBfmhtyzmiqRaNtyMuYmzHPYc3jM7qP8NbyVfTCj91l18ZUa1NKFlMT3j7tbanms1rz0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741138473; c=relaxed/simple; bh=CJ2PiRsUtvEkOe9ntMXRTLEdIi2mwE+/isxNv+IyilY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=guFfsXd6/3t39Y9EhnL4gAm6Qz5wgZi1/6g+GtP9cBkxsqQWDdHz+wMqAy0hWT+OcLCNZ+AEIOBxLWiAvKvXZHM5pV0KSrJ/O+2cVEBFnt9vxMluICgBBj793Hr2AWVVw9c3AVRtVad5wC6khG5koQCVNV/kcXuhIgyaCoZVP6E= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=qeiGC1ky; arc=none smtp.client-ip=198.137.202.133 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="qeiGC1ky" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=B4Wqcz440T2k2P6AK89RTnwayezjggDFAeKMGLMRNLs=; b=qeiGC1kyuPLPU3NG7Y/Wf/Ak4m gubnV/QlP+lb+4JkPw9Pth/CKREHOqVEdmayVoWyyKlg5NLJB/qhELzbRvVT1QugwQbPQQYTAF5JT VF+2Vm7nwDhspCwxobDp2alwbyR+5ekW9rCtxsw1dFrElqUik7c5zVgF5RWbdh3f1Ozl1QCwyWTK2 WnAq7Pfo8gfK01xeB3pT75dnavef26dOSG2C+sjae0jY+rVfqu+3cUalqJyDKQQo05BcNPJasSCsx l3VKmSXA2113Ule0YujfacCKYlYmHg+I1S2K6M90TdEMqj/nsgNDCw5bXFHitLFaxs4Vdol85uC7h IlCtblQw==; Received: from hch by bombadil.infradead.org with local (Exim 4.98 #2 (Red Hat Linux)) id 1tpdeZ-00000006jRP-22d8; Wed, 05 Mar 2025 01:34:31 +0000 Date: Tue, 4 Mar 2025 17:34:31 -0800 From: Christoph Hellwig To: Pavel Begunkov Cc: Christoph Hellwig , "Darrick J. Wong" , Christian Brauner , linux-fsdevel@vger.kernel.org, Dave Chinner , io-uring@vger.kernel.org, linux-xfs@vger.kernel.org, wu lei Subject: Re: [PATCH v2 1/1] iomap: propagate nowait to block layer Message-ID: References: <83af597f-e599-41d2-a17b-273d6d877dad@gmail.com> <20250304192205.GD2803749@frogsfrogsfrogs> <6374c617-e9a3-4e1c-86ee-502356c46557@gmail.com> Precedence: bulk X-Mailing-List: io-uring@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html On Wed, Mar 05, 2025 at 12:45:52AM +0000, Pavel Begunkov wrote: > It's not something recent. After some digging I think the > one I remember is > > https://lore.kernel.org/all/20190717150445.1131-2-axboe@kernel.dk/ > > Remove by > > commit 7b6620d7db566a46f49b4b9deab9fa061fd4b59b > Author: Jens Axboe > Date: Thu Aug 15 11:09:16 2019 -0600 > > block: remove REQ_NOWAIT_INLINE That does indeed look pretty broken, mostly because it doesn't actually return the errors inline as return values but tries to emulate it. > > If you don't want to do synchronous wouldblock errors that's your > > only option. I think it would suck badly, but it's certainly easier > > to backport. > > Is there some intrinsic difference of iomap from the block file > in block/fops.c? Or is that one broken? block/fops.c has roughly the same issue, but it's not anywhere near as sever, as block/fops.c doesn't have any file system state that gets confused by the async BLK_STS_AGAIN. But unless io_uring knows how to rewind the state for that case it probably also doesn't work properly. It might be worth to look into testcases that actually exercise the nowait I/O on block devices with annoyingly small limits or that split a lot (like RAID0).