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 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 8A073C43219 for ; Thu, 25 Apr 2019 14:11:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7349B206BF for ; Thu, 25 Apr 2019 14:11:54 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=gmx.net header.i=@gmx.net header.b="Q/GogBMT" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728543AbfDYOLx (ORCPT ); Thu, 25 Apr 2019 10:11:53 -0400 Received: from mout.gmx.net ([212.227.15.18]:38067 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726074AbfDYOLw (ORCPT ); Thu, 25 Apr 2019 10:11:52 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gmx.net; s=badeba3b8450; t=1556201508; bh=AHeUVa4rPHE71YdPAN0gE+/2+aLJ5EptljVlOb7LOMo=; h=X-UI-Sender-Class:Subject:To:Cc:References:From:Date:In-Reply-To; b=Q/GogBMT3Wnz0iKB11zVqo/lziUqXiEVoMUcAFqDM8c2QEvqZuU4M6mbAs5mPLuYF j3LW7oMYasqG2hmzzHUUasHy0JgCinEZDLd5ec2vK1kHHSV/e/McwoxwNkTe0JH5ds 59jYjb0eLfCQQ4/H6YNtWYsQE7pJb5/EO2R+1RDo= X-UI-Sender-Class: 01bb95c1-4bf8-414a-932a-4f6e2808ef9c Received: from [0.0.0.0] ([52.197.165.36]) by mail.gmx.com (mrgmx004 [212.227.17.184]) with ESMTPSA (Nemesis) id 1MBUqL-1hW5QS0DKZ-00Cy5z; Thu, 25 Apr 2019 16:11:48 +0200 Subject: Re: fallocate does not prevent ENOSPC on write To: Josef Bacik Cc: dsterba@suse.cz, Jakob Unterwurzacher , linux-btrfs@vger.kernel.org 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> 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: <20190425140957.oajm7seece2wfniz@macbook-pro-91.dhcp.thefacebook.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="v3hJ6SKfQ8yAfor7IkyOOzi7GYay1JeIU" X-Provags-ID: V03:K1:kkGGVcodVLcCk+gDfyK/+X6mxfJcwJatF6yDboDjGjSCgmM+Lht +1AaefTs3o+hP8uZsUj9TxLrvhMroEC5h/CH7EPQKdTAzr+GngENtXMxjvXMPTZWsaDjVXF dU/jPkvR8Q54Yn9wHXHVftxQjtq+3aFQ/tBsV1R5MeWhqhEUBzMi8NPoK1YQtnd4r7aIVSD 1ialqCrDUzdr7F0FimCYw== X-UI-Out-Filterresults: notjunk:1;V03:K0:JbYIaH24+EQ=:/V6QYab9WJWmFwM76voz4y 9+wMpRdaAqRQc82VGXSwmrS9X6Wq7un7/pKHX+C1MlU6u+yOdZtxQy2XVHN2e9ycHDMYGQ+lL YUogA0Qw8V0aTKWVP9jG/kgUfRbo1Sy9uW6+StBmVZneZ11izShngtCjAzOmd2L18ioNp7kZi 2Iy/sTz1mPfNmaLzvcN9K7Nt4cCitKMo/F/FkFMsethA73/DcyRUzMVUQ+wWpzajvveBxznxP evPq0k5IjQ9L172lmh/mzL7tRC0QtM8eftJO4hfSekuQgL6+mVkel/H5h7XDtKnPKQ6hWrlDC Gs64tsz7YujRWSJAxLZHBP4ON72mYICUMHCTNtEGLWFX51IvHI58QWZyuwZRgaW2Cxn/As4bM 5PrzalIYaSz+SQm5d+tOh+eSQ+LoWTbjFPQ5jDbmPAY66I1/2ehj8n+i4vh46ba6JOWnKdp1s J33co7v1z5G4EAvRuudOSp6rFZbVmp/Seq5a6DG0oezRfKg0ZAkahACs+ke/ERKAdPK7CVqyR Ao7P4DF0AqEqm7JgA+DU16R+uk3TRJZG/C08iPeeeAqBR7RDtYUUlxOJU/T7esXNMwLS8DZl6 xNZg8APYzHgI4rzYZoX6xq7EpadUmvWmX2Lr5vhFjN4JzhxkItjASqO3+y5ZigdkfNJ7LjpW4 8TdMfLv0350JlmAtZ2jzDYX4tCGHMYG/aWBxWMDa64SbKkvXT0HvRXhRhgZPKTArupLGAihhK /oDIYcG52xGJxsZ1/16hYl1VEVsJqLa2X8Q2Ny/eBVpZcVobXrkHzItcqvujgl3kH+LimAntd 5Ee/cShbk4IFb9aISYcWknojEe164psA/VBLxDbHf3Y1eeoFYQ+xy5YF0g3Yo5g9tyyB2PK6g 7Hqc4S5yEBSBIW0+wPx4Gyk8B1cjqpmQ7Wnbh8TSMJBVi9ZLJ0QAtcCVPH3Iq0 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) --v3hJ6SKfQ8yAfor7IkyOOzi7GYay1JeIU Content-Type: multipart/mixed; boundary="CLx7040MCDr92rPypaSgtPTYFbdeAfvp1"; protected-headers="v1" From: Qu Wenruo To: Josef Bacik Cc: dsterba@suse.cz, Jakob Unterwurzacher , linux-btrfs@vger.kernel.org Message-ID: <45eb63d3-affc-b4c1-d2ca-aad0ab55661c@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> In-Reply-To: <20190425140957.oajm7seece2wfniz@macbook-pro-91.dhcp.thefacebook.com> --CLx7040MCDr92rPypaSgtPTYFbdeAfvp1 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=8810:09, 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 s= hould >>>>> not the main concern here. >>>> >>> >>> Are we sure the ENOSPC is coming from the data reservation? That cha= nge makes >>> us fall back on the old behavior, which means we should still succeed= at making >>> the data reservation. >>> >>> However it fallocate() _does not_ guarantee you won't fail the metada= ta >>> 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 thi= nk >> 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 $mnt/file1 >> echo "fallocate success" >> sync >> dd if=3D/dev/zero bs=3D512K oflag=3Ddirect conv=3Dnotrunc count=3D768= of=3D$mnt/file2 >> >=20 > Wellll we don't do the nocow check _at all_ for O_DIRECT, so mystery so= lved > 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 95+0 records in 94+0 records out 49283072 bytes (49 MB, 47 MiB) copied, 0.0807034 s, 611 MB/s Thanks, Qu >=20 > Josef >=20 --CLx7040MCDr92rPypaSgtPTYFbdeAfvp1-- --v3hJ6SKfQ8yAfor7IkyOOzi7GYay1JeIU Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEELd9y5aWlW6idqkLhwj2R86El/qgFAlzBwB0ACgkQwj2R86El /qhDSAf7Bf0xpG0omjtiwKW5091igK3dY3lJs5JOfB31V38HNVG8izrKkI7WrId+ C2qWTvCnRvyaR7kR6PJDp/RcII27Id0q77WMW+0AlE06WokNrhjoh0yuB/fM6J/9 bt97iLkF0aBrFXnzUgOLpsOu8chf2CfhsUvKoCOnp711rhf+1s2Rmu/23p7davqP Weqjibng8diPuONz0AZqgcGdPOwGTjmINY0FjxhHlO8jKApqqram36fDiDhuR5/a UOU/uCUPniVM8y2BBMLHxL6eD85z0Ka7fqMAIgtPMnOr92Ig2PXR2oKnOLPw2Rpn qNJlO+8PMou1UR8W20A2RdHJoq4Caw== =WlmB -----END PGP SIGNATURE----- --v3hJ6SKfQ8yAfor7IkyOOzi7GYay1JeIU--