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 X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 95102C43219 for ; Thu, 25 Apr 2019 23:16:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9A15A20717 for ; Thu, 25 Apr 2019 23:16:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=gmx.net header.i=@gmx.net header.b="UJziqJXS" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726272AbfDYXQk (ORCPT ); Thu, 25 Apr 2019 19:16:40 -0400 Received: from mout.gmx.net ([212.227.15.15]:49997 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725970AbfDYXQj (ORCPT ); Thu, 25 Apr 2019 19:16:39 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gmx.net; s=badeba3b8450; t=1556234195; bh=wuSdJvflKXK+hsG2bS4m2V+ciEUKLKAOdfSte0W9xME=; h=X-UI-Sender-Class:Subject:To:Cc:References:From:Date:In-Reply-To; b=UJziqJXSHAsFKuoVaXKAvo7r6m4ty5XLI79ZyOznQqYs4zECoVPHLlsGe68ARE+N8 uLOPvNzhn7XTAdboPrGqslHhwMEc5Zp417e4cPaxZOxRL4cMIOOdGO5pkhRpcCosRP fDw/GEr7ZXkEZu6JC2DX+cDAv3Lq2vguUmUrKwIQ= X-UI-Sender-Class: 01bb95c1-4bf8-414a-932a-4f6e2808ef9c Received: from [0.0.0.0] ([52.197.165.36]) by mail.gmx.com (mrgmx005 [212.227.17.184]) with ESMTPSA (Nemesis) id 1N4zAs-1gd4K614iq-010sDd; Fri, 26 Apr 2019 01:16:35 +0200 Subject: Re: fallocate does not prevent ENOSPC on write To: fdmanana@gmail.com Cc: Josef Bacik , dsterba@suse.cz, Jakob Unterwurzacher , linux-btrfs References: <20190423113302.GS20156@twin.jikos.cz> <20190425132526.wjtcipkpm7fmbzyc@macbook-pro-91.dhcp.thefacebook.com> <6ce51e68-c120-ee5d-1ca3-4a6ae0727670@gmx.com> <20190425140957.oajm7seece2wfniz@macbook-pro-91.dhcp.thefacebook.com> <45eb63d3-affc-b4c1-d2ca-aad0ab55661c@gmx.com> From: Qu Wenruo Openpgp: preference=signencrypt Autocrypt: addr=quwenruo.btrfs@gmx.com; 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Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="OMltLkQvvgWXxwj2pXdMsMU4dQzhf8vLI" X-Provags-ID: V03:K1:kQ+Ust7s8dGTUW/BWvSUjH78AWgzAa5IINnPPaur+1GGaSaE/kU 1ZjVQlA2ZCyJWXHQeogIRBD/ktaZmRuzRzdF1gPA/dk/1KJDFx6YBw9ddjbHPoekq5UjIkv FKfSEKSKORdYbaYCdJ5eYRWqwMmqOvF+679avdiWJwwhoiIeX7aFIP3AfLjh8FgjzxnH9QA 5AoBbo+d3gDutExwNQMOA== X-UI-Out-Filterresults: notjunk:1;V03:K0:Qk56z8dDCMM=:JCLTP/KSz6K0jIIZamcK0f X8JdT3QcBkAExsftCtkC0DbSM0ij4KkLVVhCoAZJV4FViUaQrn/Iheo3/ICCKIFWcR8REVxmf 0kA6xIFyuwvCYO8GTf7ZuL55KBS7hVl5kgeUfIvfxVz9ByMmg60OI4a6EHJjPjr0AfwDMkpG2 mW/TANV745WGkQN4rMLF0ZNRrkdw/UYwpYBUp6uVy7Ud7kSvGXo4D/QjSs+qG1yPC/B6y0QgD tzMZ06AFO8rqHyttMpqiqtOEn10g/N2K+Ejv+OQ0/LScj4CL6YGKCS/HVF6js56cRRYBvocqi U7tMv06Ae3M1ud4PVcQXiaOKaIU1mGZKNVqdRRjf8LjplsaiJmLaK55/USp6BXhxdKT5TC56E NOIhmekRUdK+mT7mIq+N2e5WimkSZcLGnLOJXsxwIoEOtKVdLKsQye0uSTgeaFxLyruvhM+mm c0OIdJH6VRd/MQVgw6Mh4H3HCB/ASQJuo66s2mC8qd+BgbjiILWtMiL3jFmo/a/GaquN8qBUl zZ8kkqOF2KpYHPeMtgbPWvqtczRKGrlwHTs0GnY3yl8wCMovk9XcvPaRDLcskrAFm7MbKMjFS 6GsNjqTE49NAv8UPteWT0lYgEJ42T7X6Tbkgb0MudwcvyYXaw/37pEDzI1KRKaHv9MWwzAgBc eclg9lPgn1XTmxjS630TRfR9TLsdCxKHFwNH+ia5TFbkwBG/i4wh45bcFESlzC8feqbnp4wz2 /93Hb5waoevDa2ztNvK6l3g+Tyvs9sFhiws5lo9/jEIZ5LHeNzMMQUlRI9ydGtwgG119F5Fpk B3Dc1z9l8h0+1gGv1j2tl5O4kF21nMulki2jiY4Ijh7cbqK0nTj5L0oWPCyyUMmxlKQUGCNcG ucBvhOZZFXgtTrLLQdCL8KpBeuDIg6QEd9fdzOF0PL4OOJwWUreanedUJTE0+t Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --OMltLkQvvgWXxwj2pXdMsMU4dQzhf8vLI Content-Type: multipart/mixed; boundary="UgqiaQqnHuv5zPm4a1WHlRw4aIWICkM8T"; protected-headers="v1" From: Qu Wenruo To: fdmanana@gmail.com Cc: Josef Bacik , dsterba@suse.cz, Jakob Unterwurzacher , linux-btrfs Message-ID: <9acd2130-7aa1-c37c-d407-f4df1de5bb6c@gmx.com> Subject: Re: fallocate does not prevent ENOSPC on write References: <20190423113302.GS20156@twin.jikos.cz> <20190425132526.wjtcipkpm7fmbzyc@macbook-pro-91.dhcp.thefacebook.com> <6ce51e68-c120-ee5d-1ca3-4a6ae0727670@gmx.com> <20190425140957.oajm7seece2wfniz@macbook-pro-91.dhcp.thefacebook.com> <45eb63d3-affc-b4c1-d2ca-aad0ab55661c@gmx.com> In-Reply-To: --UgqiaQqnHuv5zPm4a1WHlRw4aIWICkM8T Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 2019/4/25 =E4=B8=8B=E5=8D=8810:43, Filipe Manana wrote: > On Thu, Apr 25, 2019 at 3:28 PM Qu Wenruo wrot= e: >> >> >> >> On 2019/4/25 =E4=B8=8B=E5=8D=8810:09, Josef Bacik wrote: >>> On Thu, Apr 25, 2019 at 09:50:25PM +0800, Qu Wenruo wrote: >>>> >>>> >>>> On 2019/4/25 =E4=B8=8B=E5=8D=889:25, Josef Bacik wrote: >>>> [snip] >>>>>>> >>>>>>> What if the commit is reverted, if the problem is otherwise hard = to fix? >>>>>>> This seems to break the semantics of fallocate so the performance= should >>>>>>> not the main concern here. >>>>>> >>>>> >>>>> Are we sure the ENOSPC is coming from the data reservation? That c= hange makes >>>>> us fall back on the old behavior, which means we should still succe= ed at making >>>>> the data reservation. >>>>> >>>>> However it fallocate() _does not_ guarantee you won't fail the meta= data >>>>> reservation, I suspect that may be what you are running into. >>>> >>>> For this script, we only needs 4 file extents at most. >>>> Even the initial 8M metadata should be pretty enough, thus I don't t= hink >>>> it's metadata causing the problem. >>>> --- >>>> #!/bin/bash >>>> >>>> dev=3D/dev/test/test >>>> mnt=3D/mnt/btrfs >>>> >>>> mkfs.btrfs -f $dev -b 512M >>>> >>>> mount $dev $mnt >>>> >>>> fallocate -l 384M $mnt/file1 >>>> echo "fallocate success" >>>> sync >>>> dd if=3D/dev/zero bs=3D512K oflag=3Ddirect conv=3Dnotrunc count=3D7= 68 of=3D$mnt/file2 >>>> >>> >>> Wellll we don't do the nocow check _at all_ for O_DIRECT, so mystery = solved >>> there. >> >> Oh, wrong flag, remove that oflag and we still get the same problem. >> >> fallocate success >> dd: error writing '/mnt/btrfs/file2': No space left on device >=20 > I don't get it. Why is this unexpected error? > You created a fs with 512Mb, fallocated 384Mb for a file named file1, > and then tried to write 384Mb 512K * 768 to a file named file2 (i.e. a > different file). > Wasn't the test supposed to write to file1 instead? My brain wasn't working last night. :( It should write into file1, and it passes in that case. Thanks, Qu >=20 >> 95+0 records in >> 94+0 records out >> 49283072 bytes (49 MB, 47 MiB) copied, 0.0807034 s, 611 MB/s >> >> Thanks, >> Qu >> >>> >>> Josef >>> >> >=20 >=20 --UgqiaQqnHuv5zPm4a1WHlRw4aIWICkM8T-- --OMltLkQvvgWXxwj2pXdMsMU4dQzhf8vLI Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEELd9y5aWlW6idqkLhwj2R86El/qgFAlzCP80ACgkQwj2R86El /qj6hggAiQL3coYggvb7Otkykm9m6rjTigZ+VTt2SZdgN218ibFr2rS+jdRDAMHN kBzYOoCfEgWae3FzrceHtvXr7b++AXhxOYrSv3murLIh8+8yZtxwlAnumFIABTgB seDlyRZxRMK2EMFGwnBbOCSozfShESUIO5eXr++TN28+fnWpgbBsHOCKhc74EoDt I7fH/xQDCbrd9GF0LxHfG1umWvyI/UGxULlCDPRwdNXdiFExx+HMWjfTp0sBvoQL EzF2pIjImfM7eGFcCxAA/dqmXzsFUDuwiqybjTBJ7sYUA+T11MmlKmiQ/ArmQ/yl uxtTII3tZtLTDRotK2vmDjRhmmqk6A== =Ez+R -----END PGP SIGNATURE----- --OMltLkQvvgWXxwj2pXdMsMU4dQzhf8vLI--