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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="vOFoZG2eyv77xE67vwdwra2gyITnulMin" X-Provags-ID: V03:K1:rvLzbe1+4RVV6SGV5AOrscrMGu2lm3yIY873yC3DoJ5W4VvVXMT mfCicSRnnKtGULCJz4XHrP7KGl6UelNupJ4BLlEmO/7Fp0YThv9CWzq6L6Bo0aHHjpk5UR4 qVR0e2eU7XKJMlv/NG1dOTu9A6NHX7wb8rJkx/r9FQY+lRoHXdBRzOhfq4sCxGIgtwDa5es t0qnhdTfQFk4tX038iyKQ== X-UI-Out-Filterresults: notjunk:1;V03:K0:7MxJ4quHmDg=:y8mzt9zINfVp9lj3bwX8+q Of3SV/qHMmOSb0yQZWNbKI+i7u+VvtKowWwsqoWdYpmaIZykgl1ylJ4IN30grb/+k3ByOV5m1 X+mcaFP14oh/zW5EviAObYweCfxjuNC1I/OWZklnt3zKGIhV1UajcEIQRApvk7Et3rlP35/iY /1IGMRzMILuXRf+sA1aOZ6Hm4wCodmtXVmUqtg65hw9K/F52J0F0stq7LZQhkk55fclnzvOoc 99bfpE00tr3SjXi5nMOuFreFPPqKqfkCZwHoFDUqfmgRys0N5cqL21xXOnhKKprBboCC6HlJy pLkbKf1T/CC0HV2oDuFrG1bb5z/iSSbE0fXgwuC6KQ8rbxm4zRhuGR+IPvonOHWTVmeqsZFrZ oo7TMQOy4pbeTqpkY6YC/tbxJa3ESH9Jy2yfacmX9z83w9hhBfKeSEQoPFH586Uz2C3n9mzsl F1sn/6fzxz+OlAfOpMME0d/ZbaUOwkYILJAxLFhfabL03Aqvs2QbLbeUYcPySYN4upkAY1x8U S25nflQe45CHpF7BaGkbska/1ZPFmMkw3kJxsRThI2oJEO7i8ee8z4Cxd1pVyBNYJ51sx7VNB 3qMkfWbjgIbHQ3Cox7zLd9CxruLJsjS+ZNu89A8WWX1y4wupVjehP/86az9xKcaSatwNyWf6b d4xM6CI5gS2LeArGo+7TAKRVSlvzNMJwRr3Qnb8gO8HsoJh2NLiCg4bhKcTothvc1gGpOYurE kuNj/0Ze7ufEBn6FgdaS8Qp8naNSoOrmdMS5YjN3Ec0JKk6+DGugrvd1O/DT6UDpW+Dq71yiQ WYFEhTApud/5+U2tW44FEdfbBTVECrZE2iYjoWUfCZggmR/h9V5Uw3YXVvlgM6wkKiCieY86k mCqmo9RsdcqyWDHRp40z/fKcwgbL9WKIYaXjLQF9XsPqO3+VYDnFLBRI+ZMIew/fifp4MHPIX 2hmw+zthv8eSdzXIvzcTLy6ibiN2E540= 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) --vOFoZG2eyv77xE67vwdwra2gyITnulMin Content-Type: multipart/mixed; boundary="ccELuoave8Iat6GzMRLcn0WL33eGh0ioK"; protected-headers="v1" From: Qu Wenruo To: David Sterba , linux-btrfs@vger.kernel.org Cc: Qu Wenruo Message-ID: Subject: Re: [PATCH 01/15] btrfs: fix minimum number of chunk errors for DUP References: In-Reply-To: --ccELuoave8Iat6GzMRLcn0WL33eGh0ioK Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 2019/5/17 =E4=B8=8B=E5=8D=885:43, David Sterba wrote: > The list of profiles in btrfs_chunk_max_errors lists DUP as a profile > DUP able to tolerate 1 device missing. Though this profile is special > with 2 copies, it still needs the device, unlike the others. >=20 > Looking at the history of changes, thre's no clear reason why DUP is > there, functions were refactored and blocks of code merged to one > helper. >=20 > d20983b40e828 Btrfs: fix writing data into the seed filesystem > - factor code to a helper >=20 > de11cc12df173 Btrfs: don't pre-allocate btrfs bio > - unrelated change, DUP still in the list with max errors 1 >=20 > a236aed14ccb0 Btrfs: Deal with failed writes in mirrored configurations= > - introduced the max errors, leaves DUP and RAID1 in the same group >=20 > CC: Qu Wenruo > Signed-off-by: David Sterba Just some extra hint for the tolerance of DUP profile. In case of DUP, either all stripes are missing, or all stripes exist. So no matter whether the tolerance is 0 or 1, it will always work. But indeed, setting it to 0 is more accurate. Thanks, Qu > --- > fs/btrfs/volumes.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) >=20 > diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c > index 1c2a6e4b39da..8508f6028c8d 100644 > --- a/fs/btrfs/volumes.c > +++ b/fs/btrfs/volumes.c > @@ -5328,8 +5328,7 @@ static inline int btrfs_chunk_max_errors(struct m= ap_lookup *map) > =20 > if (map->type & (BTRFS_BLOCK_GROUP_RAID1 | > BTRFS_BLOCK_GROUP_RAID10 | > - BTRFS_BLOCK_GROUP_RAID5 | > - BTRFS_BLOCK_GROUP_DUP)) { > + BTRFS_BLOCK_GROUP_RAID5)) { > max_errors =3D 1; > } else if (map->type & BTRFS_BLOCK_GROUP_RAID6) { > max_errors =3D 2; >=20 --ccELuoave8Iat6GzMRLcn0WL33eGh0ioK-- --vOFoZG2eyv77xE67vwdwra2gyITnulMin Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEELd9y5aWlW6idqkLhwj2R86El/qgFAlzev5AACgkQwj2R86El /qgLIAf/ee2JG+XlDzz1qh1C29SOhJdneRswSS2Ci0Fk86/0REq/wwaGaZDEPp67 3pKhZtGdNJWvLFEDdPw8Ob1DsU2osc+avgEQdtQm5v9d4IB88Ic2im7qdzGIJzxq ztjJx9MDUaF49lXV2TcUhxVy9UhYbR7MX7WqjxsnxzvDSJgf2JofJfRKnzW0Rff0 3JZO8b9Lle1gIDDiEBVaYJoto2OsknZl68ETWy3V7+CjZ+Wn6/0MIsUFEmj33gzX b05dAI94a6W2fWHSymncZIGBezTGeUTXFFaDcjgCkF5RtZf+TMOHKsWWgOC15Y97 ESSJypha/g4HqCqyJzqiynHo/CTFmg== =w9ZF -----END PGP SIGNATURE----- --vOFoZG2eyv77xE67vwdwra2gyITnulMin--