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Thu, 31 Jan 2019 01:45:47 +0100 Subject: Re: [PATCH v4 04/12] btrfs: extent_io: Move the BUG_ON() in flush_write_bio() one level up To: dsterba@suse.cz, Qu Wenruo , linux-btrfs@vger.kernel.org References: <20190125050925.30754-1-wqu@suse.com> <20190125050925.30754-5-wqu@suse.com> <20190130151914.GU2900@twin.jikos.cz> 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: <3893155e-d3c3-5fd0-6f61-ae067d341d81@gmx.com> Date: Thu, 31 Jan 2019 08:45:42 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 In-Reply-To: <20190130151914.GU2900@twin.jikos.cz> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="6oo4ewj2dfFOeB04YLZwUGj59Sw06j8cO" X-Provags-ID: V03:K1:YP1dTfJc7lFewVN4AlysUqq6d+jXsPpEkM3qXp/pVGRdsbve/i/ JZMz9f10R502PvJ7S3hxZT9tVuKYKtskyhy/T/hgyv6rj8tCVQbsBTKhiCad77akhGc5qrI iKQsvyQ3M2cH0FdAfCEu4naV+we9i1LtdPdJ2w+3qOveEKBxGdnM2vBx4PNFNq5SS9eueFt IYOfrQ+f8ee1oCD5hxFqQ== X-UI-Out-Filterresults: notjunk:1;V03:K0:9P5DjA56WuA=:Dx+MOZcCsP1FLL45+sXGY8 NhTaz9nz2DqJIWEsktYCm33uch2a/wM4+iAATFrwGrZMWHpHCiVVuUVM8P4PF/m6r03IYm5Xy YmNZMZlVvzYs0gZQmJRz4CcABzuWRmgHQcSbB5wPTNdfqZ649VPlvULdJfPJdviCFPliTWefR 7tiVsOWoxkeC0AOOLrGD/wenI7vi/b9/bP+tu8Vz/srcII2y9ZbS6+9LBpvEBHmCGIK8s9Flh nRUSM+N3PxS6GiZhEK8Gu7v/0H40zIc8ZxLWxtNI2YHAr77MLdOe2RUWI1giJV8zZUQIWQKyL E+JwGgMNq/O1oV8XCBDc2jA9sRBQoexJIHyCquJ/P4/hR20YWoo0mVFCSl9sz6MBY8otDPl40 FOy0ILyODk9lKTi1LXlNEqme3t/5f6j0aCPaaxeIBMJxYC0YgORNUO0+GTyONdL+FF2snvOpV HMM7YyQP9hPboZFtvd2UTNFPus7ZvOZzGCOowW/r6bYV71s3I2ZdIAKakShg2MdzCBs1lgj0z +D6MRkfiec7rO4JZdH90QP89+E9+2BeAQU1JhnxLKBIO8kceLb1YBveUzYq1iG19j4kSuORPP i5tmA19YENFYTpfALB0LIvjAJwZZrjdZURwZVYrVAT86zjOtq8MsB/geu1yoU8X7Pz3aYxtuW 6C+1eDper7Yd1LiYckKuG0j+Wf3fKyetlRrccP4wjc0ienATBnnmHXlmb3z8DsdYTNs6SD66W JdS9XAyNBk3y3LjHlnUsjnHGy9VGI6YQhRTfnqZQo29imgLc7nX7u6DrspkRf796ahv20IA5n iUNxI9HczitYhdboSCv6aKWwWgA1x0v8v+596V3qLcio/VuFcddJUWKCZeiKErfU9ZhiK600C DtJAFIQu9aEm954pjpEJvqGd58pIMqvP3WZ6ySUeVC6iVPb0y1gsgexWJfPNWQ 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) --6oo4ewj2dfFOeB04YLZwUGj59Sw06j8cO Content-Type: multipart/mixed; boundary="9eLmOjusWYLXRR8teahvesbJG74s86t31"; protected-headers="v1" From: Qu Wenruo To: dsterba@suse.cz, Qu Wenruo , linux-btrfs@vger.kernel.org Message-ID: <3893155e-d3c3-5fd0-6f61-ae067d341d81@gmx.com> Subject: Re: [PATCH v4 04/12] btrfs: extent_io: Move the BUG_ON() in flush_write_bio() one level up References: <20190125050925.30754-1-wqu@suse.com> <20190125050925.30754-5-wqu@suse.com> <20190130151914.GU2900@twin.jikos.cz> In-Reply-To: <20190130151914.GU2900@twin.jikos.cz> --9eLmOjusWYLXRR8teahvesbJG74s86t31 Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 2019/1/30 =E4=B8=8B=E5=8D=8811:19, David Sterba wrote: > On Fri, Jan 25, 2019 at 01:09:17PM +0800, Qu Wenruo wrote: >> +static int __must_check flush_write_bio(struct extent_page_data *epd)= >> { >> - if (epd->bio) { >> - int ret; >> + int ret =3D 0; >> =20 >> + if (epd->bio) { >> ret =3D submit_one_bio(epd->bio, 0, 0); >> - BUG_ON(ret < 0); /* -ENOMEM */ >> epd->bio =3D NULL; >=20 > I'm not sure if resetting epd->bio to NULL is all that needs to be done= > here. With the BUG_ON the error case never happens so if all goes fine > it's also ok to set it to NULL and continue. But the callers might need= > to send the flush again. If flush_write_bio() get called again on the failed one, it will just get skipped as epd->bio is NULL, submit_one_bio() will not be triggered.= Thanks, Qu >=20 > It's not easy to trace the bio here, it's set indirectly in > submit_extent_page, submit_one_bio is another indirection, switching by= > type and sometimes bio_endio is called in case of an error. >=20 --9eLmOjusWYLXRR8teahvesbJG74s86t31-- --6oo4ewj2dfFOeB04YLZwUGj59Sw06j8cO Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEELd9y5aWlW6idqkLhwj2R86El/qgFAlxSRTYACgkQwj2R86El /qjerwf/Wp0CaDdzNO1p6ak2+Aq24wBl/N6PbgRsXko5q9sboc14jE7f4kstRjrV XxCN43avbgxFAt5bgJUktp4kYupaEynjSpQrYh7MmYGWf6HUc6rmnHDr3IlsDePF Uhw4VUD8ONhiRygl4Er7aaQpMSGQu//IMDp+yzPaJo5x/Z0fNTTPF/aDzGPN0IO8 M7g4lRow5gTkIKwIO7UalXLstnAADeHBD/ADQkcXqo4VaUu5WwHgOauWJnJhpkHS XlyE0T6YMhgbeZTJ3mUhEjekKMB98eKqEmpe5Cpao0l4a1mz2zDc1AIXJ3MZY5LC N3s6Kr7MW3YDkQ3IKnCVquBen+W8/Q== =Lo6d -----END PGP SIGNATURE----- --6oo4ewj2dfFOeB04YLZwUGj59Sw06j8cO--