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Tue, 26 Feb 2019 02:39:07 -0500 Received: from [0.0.0.0] ([149.28.201.231]) by mail.gmx.com (mrgmx002 [212.227.17.184]) with ESMTPSA (Nemesis) id 0MfVU3-1gfVIv2XKF-00P7Ku; Tue, 26 Feb 2019 08:38:59 +0100 Subject: Re: [RFC PATCH] btrfs: Introduce developer-oriented check to ensure all tree blocks are written back before writing super blocks To: Qu Wenruo , linux-btrfs@vger.kernel.org References: <20190221082249.24187-1-wqu@suse.com> From: Qu Wenruo Openpgp: preference=signencrypt Autocrypt: addr=quwenruo.btrfs@gmx.com; prefer-encrypt=mutual; keydata= mQENBFnVga8BCACyhFP3ExcTIuB73jDIBA/vSoYcTyysFQzPvez64TUSCv1SgXEByR7fju3o 8RfaWuHCnkkea5luuTZMqfgTXrun2dqNVYDNOV6RIVrc4YuG20yhC1epnV55fJCThqij0MRL 1NxPKXIlEdHvN0Kov3CtWA+R1iNN0RCeVun7rmOrrjBK573aWC5sgP7YsBOLK79H3tmUtz6b 9Imuj0ZyEsa76Xg9PX9Hn2myKj1hfWGS+5og9Va4hrwQC8ipjXik6NKR5GDV+hOZkktU81G5 gkQtGB9jOAYRs86QG/b7PtIlbd3+pppT0gaS+wvwMs8cuNG+Pu6KO1oC4jgdseFLu7NpABEB AAG0IlF1IFdlbnJ1byA8cXV3ZW5ydW8uYnRyZnNAZ214LmNvbT6JAVQEEwEIAD4CGwMFCwkI BwIGFQgJCgsCBBYCAwECHgECF4AWIQQt33LlpaVbqJ2qQuHCPZHzoSX+qAUCWdWCnQUJCWYC bgAKCRDCPZHzoSX+qAR8B/94VAsSNygx1C6dhb1u1Wp1Jr/lfO7QIOK/nf1PF0VpYjTQ2au8 ihf/RApTna31sVjBx3jzlmpy+lDoPdXwbI3Czx1PwDbdhAAjdRbvBmwM6cUWyqD+zjVm4RTG rFTPi3E7828YJ71Vpda2qghOYdnC45xCcjmHh8FwReLzsV2A6FtXsvd87bq6Iw2axOHVUax2 FGSbardMsHrya1dC2jF2R6n0uxaIc1bWGweYsq0LXvLcvjWH+zDgzYCUB0cfb+6Ib/ipSCYp 3i8BevMsTs62MOBmKz7til6Zdz0kkqDdSNOq8LgWGLOwUTqBh71+lqN2XBpTDu1eLZaNbxSI ilaVuQENBFnVga8BCACqU+th4Esy/c8BnvliFAjAfpzhI1wH76FD1MJPmAhA3DnX5JDORcga CbPEwhLj1xlwTgpeT+QfDmGJ5B5BlrrQFZVE1fChEjiJvyiSAO4yQPkrPVYTI7Xj34FnscPj /IrRUUka68MlHxPtFnAHr25VIuOS41lmYKYNwPNLRz9Ik6DmeTG3WJO2BQRNvXA0pXrJH1fN GSsRb+pKEKHKtL1803x71zQxCwLh+zLP1iXHVM5j8gX9zqupigQR/Cel2XPS44zWcDW8r7B0 q1eW4Jrv0x19p4P923voqn+joIAostyNTUjCeSrUdKth9jcdlam9X2DziA/DHDFfS5eq4fEv ABEBAAGJATwEGAEIACYWIQQt33LlpaVbqJ2qQuHCPZHzoSX+qAUCWdWBrwIbDAUJA8JnAAAK CRDCPZHzoSX+qA3xB/4zS8zYh3Cbm3FllKz7+RKBw/ETBibFSKedQkbJzRlZhBc+XRwF61mi f0SXSdqKMbM1a98fEg8H5kV6GTo62BzvynVrf/FyT+zWbIVEuuZttMk2gWLIvbmWNyrQnzPl mnjK4AEvZGIt1pk+3+N/CMEfAZH5Aqnp0PaoytRZ/1vtMXNgMxlfNnb96giC3KMR6U0E+siA 4V7biIoyNoaN33t8m5FwEwd2FQDG9dAXWhG13zcm9gnk63BN3wyCQR+X5+jsfBaS4dvNzvQv h8Uq/YGjCoV1ofKYh3WKMY8avjq25nlrhzD/Nto9jHp8niwr21K//pXVA81R2qaXqGbql+zo Message-ID: Date: Tue, 26 Feb 2019 15:38:54 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.5.1 MIME-Version: 1.0 In-Reply-To: <20190221082249.24187-1-wqu@suse.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="jGtMOnuwBLvsqYOGwoNkpd6qZlAzEVT1C" X-Provags-ID: V03:K1:mnsEXHJxLxrmW5IT1cqmfDkVjLt89tEenDCDTsevDv3lgEGN2T8 gliqNZzV8YR+BkDvHN2kLf2ciUQMGjs/5Or3H6uwmGncvtHUQ6GVipJTwgQ0l1diDjlHjmK qV7nkvDDRVXaDYpC3BwCAH+oDHYDQ8z6scUDdaLXlXkzbZKLanf5OyQSqQ8XPVQgzUj3p+G wwUY3pYPzlmyevXdeqhcA== X-UI-Out-Filterresults: notjunk:1;V03:K0:xK0Ug3zwjFk=:etKooTxxNTRwBdeAcCV8Ci UHPc4UfgJCtPHqWLaQsfyejvuWUfGcS4B3Zv1ghya6498zFq6pQ4UwUG4OLNnM+hvIzMzyVTQ nb9SrcxxpNlwNXI/8ivWP43yu/vvEBkALsVAyrOd0MgcslZAKU2Oth+YlkQB2k1KOhKi0YS8x 89YfcY3/FkByCIA/m2nSqcX9lhixymrEmwJIkCvSzhN5j8UWwSlY0AsOv9CVsDoiOZSZtgSIy huFYKIn2pOZCyG++byMUsv5Z3QUFW6+kvquGFmfZJ+LiBYBQu6FoiNrcbecAaVj21M10UZRUZ qd17MfDdCNZPbVHjp2oaBPt7A73WlwT9qT8Hfhg0Q3ThVs95Nrtk7a795XVS2goX+9dqnelTK igRqb9LLCnRD2cV78PaYO5HgSxUBmFi4Gm9lciJ1DD3Gr3VF9ULB5uRlctgwjcwkaq6yKPilE XbUE2A5R28XUMt6BPk9Ve03KUQhiPUaJx5plExvAjgVjkcZrxr57yoA7D6SwHIPUKP006VgWP xeJoigKiLw+Q5kOjfc4wOJxOLIiP6h92cRlt4H43ZArDnXFFz0/SeKHDu50ktLNSGGxQyj6OR OzkKSBFOYVbNhxA7olnBdzioFc7hBdrBoptckSu1cICIE6xX7GFPTH8kEfwes4ncULI8J4f4Z FSVlf8cVjKnndGDZnkiBzibsDgn3A5MiGpilGs/htgExTbrhsU0gaMdN3WeIVuy912ez9XHjy s7e+zJ4/U52Izn3iQj1PB0P6kDmeCgvox+fT0LQMg6duSXDkTQreRUmoaDTXZCvMZN4o+IVyb 2yWtl8DOCM6JX43mGW/n/IYJkTd1HB1TJ7LpTvR46xXZSH0Sy7cWCsPg9a18QSgVboIUERotz Zxkn10lXLSWdC5xHvotUYFovH1y5pxh7lXqf44Cm30rqvxNrOPvQPvvN97KXqC 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) --jGtMOnuwBLvsqYOGwoNkpd6qZlAzEVT1C Content-Type: multipart/mixed; boundary="jkWvFyvMFUMjcctAWCY5IyK6mSJdEMvLx"; protected-headers="v1" From: Qu Wenruo To: Qu Wenruo , linux-btrfs@vger.kernel.org Message-ID: Subject: Re: [RFC PATCH] btrfs: Introduce developer-oriented check to ensure all tree blocks are written back before writing super blocks References: <20190221082249.24187-1-wqu@suse.com> In-Reply-To: <20190221082249.24187-1-wqu@suse.com> --jkWvFyvMFUMjcctAWCY5IyK6mSJdEMvLx Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 2019/2/21 =E4=B8=8B=E5=8D=884:22, Qu Wenruo wrote: > There are a lot of error reports complaining about transid error in the= > mail list. >=20 > Under most case, the on-disk transid is lower than expected transid. > This may indicate that some tree blocks are not written back to disk > before writing super blocks. >=20 > This patch will add a safe net for developers, by calling > btrfs_write_and_wait_transaction() before setting transaction unblocked= > and double check btree_inode and dirty_pages io_tree, to ensure no tree= > blocks are still dirty or under writeback. >=20 > Signed-off-by: Qu Wenruo Please discard this patch. As Nikolay suggested, the check doesn't make much sense. > =20 > + /* Last safenet or developer to catch any unwritten tree blocks */ > + if (IS_ENABLED(CONFIG_BTRFS_DEBUG)) { > + u64 found_start =3D 0; > + u64 found_end =3D 0; > + > + ret =3D btrfs_write_and_wait_transaction(trans); > + if (ret) { > + btrfs_handle_fs_error(fs_info, ret, > + "Error while writing out transaction"); > + mutex_unlock(&fs_info->tree_log_mutex); > + goto scrub_continue; > + } > + > + /* No dirty extent should exist in btree inode */ > + ret =3D test_range_bit(&trans->transaction->dirty_pages, 0, > + (u64)-1, EXTENT_DIRTY | EXTENT_WRITEBACK, > + 0, NULL); For dirty_pages, btrfs_write_and_wait_transaction() will clear all bits. So the check will always return 0. > + if (ret > 0) { > + WARN(1, > + "dirty_pages not fully written back, start=3D%llu len=3D%llu\n", > + found_start, found_end + 1 - found_start); > + ret =3D -EUCLEAN; > + mutex_unlock(&fs_info->tree_log_mutex); > + goto scrub_continue; > + } > + ret =3D test_range_bit(&BTRFS_I(fs_info->btree_inode)->io_tree, 0, > + (u64)-1, EXTENT_DIRTY | EXTENT_WRITEBACK, > + 0, NULL); btree_inode doesn't really carry EXTENT_DIRTY bit. It only carries EXTENT_LOCK, and are mostly for tree read locking. So this check doesn't make much sense either. Thanks, Qu > + if (ret > 0) { > + WARN(1, > + "btree io_tree not fully written back, start=3D%llu len=3D%llu\n", > + found_start, found_end + 1 - found_start); > + ret =3D -EUCLEAN; > + mutex_unlock(&fs_info->tree_log_mutex); > + goto scrub_continue; > + } > + } > + > spin_lock(&fs_info->trans_lock); > cur_trans->state =3D TRANS_STATE_UNBLOCKED; > fs_info->running_transaction =3D NULL; >=20 --jkWvFyvMFUMjcctAWCY5IyK6mSJdEMvLx-- --jGtMOnuwBLvsqYOGwoNkpd6qZlAzEVT1C Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEELd9y5aWlW6idqkLhwj2R86El/qgFAlx07Q4ACgkQwj2R86El /qg89gf/XpSkb9dQxsFxQYWb4rD5FKY0vL6F0mUARASLTDcT64imfCfmFy5mGyDd H+dw6qmMkn5+u112g/HH/DekoQp0KWUdoDjKwEwBR1wOYQgfRQv94DO9rF8kuydx 8OTlmv5bkzJMI2EINiSKS5y/3ZuKxVmAm85xTrZwvFDPOwq/z9vcZ71FAcumN0GV 61uyAzW7oMLdsm5SCPaCQ51nu5Ge4KvOB9z7NY+tw7goKpJucU3U2Ns2b57tTeUG 5RjAxljTIfnOmS24WzDM+L18q/82Ugf2k+492Mj03Q3Ad9xhIA7glTkSW62ri3Bg +1dYqsx2Z3bSujkADPzwUtrBPdpttw== =IrsP -----END PGP SIGNATURE----- --jGtMOnuwBLvsqYOGwoNkpd6qZlAzEVT1C--