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=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=no 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 546DCC4363D for ; Tue, 6 Oct 2020 12:56:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 083E9206F7 for ; Tue, 6 Oct 2020 12:56:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726317AbgJFM4L (ORCPT ); Tue, 6 Oct 2020 08:56:11 -0400 Received: from static.214.254.202.116.clients.your-server.de ([116.202.254.214]:45150 "EHLO ciao.gmane.io" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726032AbgJFM4K (ORCPT ); Tue, 6 Oct 2020 08:56:10 -0400 Received: from list by ciao.gmane.io with local (Exim 4.92) (envelope-from ) id 1kPmQt-0008io-Sa for linux-btrfs@vger.kernel.org; Tue, 06 Oct 2020 14:51:07 +0200 X-Injected-Via-Gmane: http://gmane.org/ Mail-Followup-To: linux-btrfs@vger.kernel.org To: linux-btrfs@vger.kernel.org From: Torsten Bronger Subject: Re: Why so much "btrfs send" data for "cp -a --reflink"? Date: Tue, 06 Oct 2020 14:48:21 +0200 Organization: Phoenix Foundation Message-ID: <87a6wzplka.fsf@physik.rwth-aachen.de> References: <87362t3y67.fsf@physik.rwth-aachen.de> Mime-Version: 1.0 Content-Type: multipart/signed; boundary="=-=-="; micalg=sha256; protocol="application/pkcs7-signature" User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.0.50 (gnu/linux) Cancel-Lock: sha1:903oDX9ysbwvpW0zxebJlYxHINk= X-PGP-Fingerprint: C5C8 D6E2 79D2 EFE9 8C0F 6D77 D5E3 CEFC 9F51 6B77 X-PGP-Affinity: will accept encrypted message for GPG X-Home-Page: http://www.wikipedia.org/wiki/User:Bronger X-Face: +wpw"|jN2Fde|7_lKBa0\7!_6suIE_m! x)'S9ytBu8tkt'k779jbzQ4o|p+@H_DCrIdnKG]E*w X-Binford: 6100 (more power) X-Accept-Language: de, en Jabber-ID: torsten.bronger@jabber.rwth-aachen.de Mail-Copies-To: never Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org --=-=-= Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Hall=C3=B6chen! Torsten Bronger writes: > I have two subvolumes A and B. =E2=80=9EA=E2=80=9C contains 50GB data, B= is empty. > None is a snapshot of the other. Now, I copy all data from A to B > with "cp -a --reflink A/* B". This copying takes less than a > second. So apparently, no bulk data was duplicated. "diff -rq A B" > is empty. So far, so good. > > However, it surprises me that > > btrfs send -p A B | wc -c > > reports 12GB. At , I have uploaded the output of "btrfs receive --dump". Apparently, there are many "write". Why doesn=E2=80=99t btrfs detect that all those extents are present in the parent? Regards, Torsten. =2D-=20 Torsten Bronger --=-=-= Content-Type: application/pkcs7-signature; name=smime.p7s Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename=smime.p7s MIAGCSqGSIb3DQEHAqCAMIACAQExDzANBglghkgBZQMEAgEFADCABgkqhkiG9w0BBwEAAKCCEI8w ggUSMIID+qADAgECAgkA4wvV+K8l2YEwDQYJKoZIhvcNAQELBQAwgYIxCzAJBgNVBAYTAkRFMSsw KQYDVQQKDCJULVN5c3RlbXMgRW50ZXJwcmlzZSBTZXJ2aWNlcyBHbWJIMR8wHQYDVQQLDBZULVN5 c3RlbXMgVHJ1c3QgQ2VudGVyMSUwIwYDVQQDDBxULVRlbGVTZWMgR2xvYmFsUm9vdCBDbGFzcyAy MB4XDTE2MDIyMjEzMzgyMloXDTMxMDIyMjIzNTk1OVowgZUxCzAJBgNVBAYTAkRFMUUwQwYDVQQK EzxWZXJlaW4genVyIEZvZXJkZXJ1bmcgZWluZXMgRGV1dHNjaGVuIEZvcnNjaHVuZ3NuZXR6ZXMg ZS4gVi4xEDAOBgNVBAsTB0RGTi1QS0kxLTArBgNVBAMTJERGTi1WZXJlaW4gQ2VydGlmaWNhdGlv biBBdXRob3JpdHkgMjCCASIwDQYJKoZIhvcNAQEBBQADggEPADCCAQoCggEBAMtg1/9moUHN0vqH l4pzq5lN6mc5WqFggEcVToyVsuXPztNXS43O+FZsFVV2B+pG/cgDRWM+cNSrVICxI5y+NyipCf8F XRgPxJiZN7Mg9mZ4F4fCnQ7MSjLnFp2uDo0peQcAIFTcFV9Kltd4tjTTwXS1nem/wHdN6r1ZB+Ba L2w8pQDcNb1lDY9/Mm3yWmpLYgHurDg0WUU2SQXaeMpqbVvAgWsRzNI8qIv4cRrKO+KA3Ra0Z3qL NupOkSk9s1FcragMvp0049ENF4N1xDkesJQLEvHVaY4l9Lg9K7/AjsMeO6W/VRCrKq4Xl14zzsjz 9AkH4wKGMUZrAcUQDBHHWekCAwEAAaOCAXQwggFwMA4GA1UdDwEB/wQEAwIBBjAdBgNVHQ4EFgQU k+PYMiba1fFKpZFK4OpL4qIMz+EwHwYDVR0jBBgwFoAUv1kgNgB5oKAia4zV8mHSuCzLgkowEgYD VR0TAQH/BAgwBgEB/wIBAjAzBgNVHSAELDAqMA8GDSsGAQQBga0hgiwBAQQwDQYLKwYBBAGBrSGC LB4wCAYGZ4EMAQICMEwGA1UdHwRFMEMwQaA/oD2GO2h0dHA6Ly9wa2kwMzM2LnRlbGVzZWMuZGUv cmwvVGVsZVNlY19HbG9iYWxSb290X0NsYXNzXzIuY3JsMIGGBggrBgEFBQcBAQR6MHgwLAYIKwYB BQUHMAGGIGh0dHA6Ly9vY3NwMDMzNi50ZWxlc2VjLmRlL29jc3ByMEgGCCsGAQUFBzAChjxodHRw Oi8vcGtpMDMzNi50ZWxlc2VjLmRlL2NydC9UZWxlU2VjX0dsb2JhbFJvb3RfQ2xhc3NfMi5jZXIw DQYJKoZIhvcNAQELBQADggEBAIcL/z4Cm2XIVi3WO5qYi3FP2ropqiH5Ri71sqQPrhE4eTizDnS6 dl2e6BiClmLbTDPo3flq3zK9LExHYFV/53RrtCyD2HlrtrdNUAtmB7Xts5et6u5/MOaZ/SLick0+ hFvu+c+Z6n/XUjkurJgARH5pO7917tALOxrN5fcPImxHhPalR6D90Bo0fa3SPXez7vTXTf/D6OWS T1k+kEcQSrCFWMBvf/iu7QhCnh7U3xQuTY+8npTD5+32GPg8SecmqKc22CzeIs2LgtjZeOJVEqM7 h0S2EQvVDFKvaYwPBt/QolOLV5h7z/0HJPT8vcP9SpIClxvyt7bPZYoaorVyGTkwggWsMIIElKAD AgECAgcbY7rQHiw9MA0GCSqGSIb3DQEBCwUAMIGVMQswCQYDVQQGEwJERTFFMEMGA1UEChM8VmVy ZWluIHp1ciBGb2VyZGVydW5nIGVpbmVzIERldXRzY2hlbiBGb3JzY2h1bmdzbmV0emVzIGUuIFYu MRAwDgYDVQQLEwdERk4tUEtJMS0wKwYDVQQDEyRERk4tVmVyZWluIENlcnRpZmljYXRpb24gQXV0 aG9yaXR5IDIwHhcNMTYwNTI0MTEzODQwWhcNMzEwMjIyMjM1OTU5WjCBjTELMAkGA1UEBhMCREUx RTBDBgNVBAoMPFZlcmVpbiB6dXIgRm9lcmRlcnVuZyBlaW5lcyBEZXV0c2NoZW4gRm9yc2NodW5n c25ldHplcyBlLiBWLjEQMA4GA1UECwwHREZOLVBLSTElMCMGA1UEAwwcREZOLVZlcmVpbiBHbG9i YWwgSXNzdWluZyBDQTCCASIwDQYJKoZIhvcNAQEBBQADggEPADCCAQoCggEBAJ07eRxH3h+Gy8Zp 1xCeOdfZojDbchwFfylfS2jxrRnWTOFrG7ELf6Gr4HuLi9gtzm6IOhDuV+UefwRRNuu6cG1joL6W LkDh0YNMZj0cZGnlm6Stcq5oOVGHecwX064vXWNxSzl660Knl5BpBb+Q/6RAcL0D57+eGIgfn5mI TQ5HjUhfZZkQ0tkqSe3BuS0dnxLLFdM/fx5ULzquk1enfnjK1UriGuXtQX1TX8izKvWKMKztFwUk P7agCwf9TRqaA1KgNpzeJIdl5Of6x5ZzJBTN0OgbaJ4YWa52fvfRCng8h0uwN89Tyjo4EPPLR22M ZD08WkVKusqAfLjz56dMTM0CAwEAAaOCAgUwggIBMBIGA1UdEwEB/wQIMAYBAf8CAQEwDgYDVR0P AQH/BAQDAgEGMCkGA1UdIAQiMCAwDQYLKwYBBAGBrSGCLB4wDwYNKwYBBAGBrSGCLAEBBDAdBgNV HQ4EFgQUazqYi/nyU4na4K2yMh4JH+iqO3QwHwYDVR0jBBgwFoAUk+PYMiba1fFKpZFK4OpL4qIM z+EwgY8GA1UdHwSBhzCBhDBAoD6gPIY6aHR0cDovL2NkcDEucGNhLmRmbi5kZS9nbG9iYWwtcm9v dC1nMi1jYS9wdWIvY3JsL2NhY3JsLmNybDBAoD6gPIY6aHR0cDovL2NkcDIucGNhLmRmbi5kZS9n bG9iYWwtcm9vdC1nMi1jYS9wdWIvY3JsL2NhY3JsLmNybDCB3QYIKwYBBQUHAQEEgdAwgc0wMwYI KwYBBQUHMAGGJ2h0dHA6Ly9vY3NwLnBjYS5kZm4uZGUvT0NTUC1TZXJ2ZXIvT0NTUDBKBggrBgEF BQcwAoY+aHR0cDovL2NkcDEucGNhLmRmbi5kZS9nbG9iYWwtcm9vdC1nMi1jYS9wdWIvY2FjZXJ0 L2NhY2VydC5jcnQwSgYIKwYBBQUHMAKGPmh0dHA6Ly9jZHAyLnBjYS5kZm4uZGUvZ2xvYmFsLXJv b3QtZzItY2EvcHViL2NhY2VydC9jYWNlcnQuY3J0MA0GCSqGSIb3DQEBCwUAA4IBAQCBeEWkTqR/ DlXwCbFqPnjMaDWpHPOVnj/z+N9rOHeJLI21rT7H8pTNoAauusyosa0zCLYkhmI2THhuUPDVbmCN T1IxQ5dGdfBi5G5mUcFCMWdQ5UnnOR7Ln8qGSN4IFP8VSytmm6A4nwDO/afr0X9XLchMX9wQEZc+ lgQCXISoKTlslPwQkgZ7nu7YRrQbtQMMONncsKk/cQYLsgMHM8KNSGMlJTx6e1du94oFOO+4oK4v 9NsH1VuEGMGpuEvObJAaguS5Pfp38dIfMwK/U+d2+dwmJUFvL6Yb+qQTkPp8ftkLYF3sv8pBoGH7 EUkp2KgtdRXYShjqFu9VNCIaE40GMIIFxTCCBK2gAwIBAgIMITwlCcbKdKftcTO4MA0GCSqGSIb3 DQEBCwUAMIGNMQswCQYDVQQGEwJERTFFMEMGA1UECgw8VmVyZWluIHp1ciBGb2VyZGVydW5nIGVp bmVzIERldXRzY2hlbiBGb3JzY2h1bmdzbmV0emVzIGUuIFYuMRAwDgYDVQQLDAdERk4tUEtJMSUw IwYDVQQDDBxERk4tVmVyZWluIEdsb2JhbCBJc3N1aW5nIENBMB4XDTE5MDcwMzEzMDI1NVoXDTIy MDcwMjEzMDI1NVowWTELMAkGA1UEBhMCREUxFDASBgNVBAoMC1JXVEggQWFjaGVuMRowGAYDVQQL DBFGYWNoZ3J1cHBlIFBoeXNpazEYMBYGA1UEAwwPVG9yc3RlbiBCcm9uZ2VyMIIBIjANBgkqhkiG 9w0BAQEFAAOCAQ8AMIIBCgKCAQEAxIt1wvBlWL2/0G7NCH8mUFfYMKxDGvkhTDYpmB4k+6GtNT9l 2mka4RjFpNyd/e5l3/ocZ3IhmGKwAaqB6tuIuIfgYP5J1jZ5msb11uHL7Bpx7phFXC6EG0ML3zk0 qcdSibcSHVtxiaI7fl+O1y9XGc0DVXVTWn15uv2SsXNXhVHTGe6Z+wpdCssWV2pi+b4crAAp7K3t 2mUikg/uacH4R8YGoCUPVDitg3U+KUQK8PSFjBU+4FmS9fkXDdu8HeEWQevJqfPdMl4KTkPaR4iz SoP4pagxRsGZ4CsweHt4NvrfDkFxmNuocXs1urmnCgYV9L7iZpkWdFyP6RVfiNae0wIDAQABo4IC VjCCAlIwPgYDVR0gBDcwNTAPBg0rBgEEAYGtIYIsAQEEMBAGDisGAQQBga0hgiwBAQQEMBAGDisG AQQBga0hgiwCAQQEMAkGA1UdEwQCMAAwDgYDVR0PAQH/BAQDAgXgMB0GA1UdJQQWMBQGCCsGAQUF BwMCBggrBgEFBQcDBDAdBgNVHQ4EFgQUNZQD5+pPH0gqw7F8YDbUDcYUuJowHwYDVR0jBBgwFoAU azqYi/nyU4na4K2yMh4JH+iqO3QwKAYDVR0RBCEwH4EdYnJvbmdlckBwaHlzaWsucnd0aC1hYWNo ZW4uZGUwgY0GA1UdHwSBhTCBgjA/oD2gO4Y5aHR0cDovL2NkcDEucGNhLmRmbi5kZS9kZm4tY2Et Z2xvYmFsLWcyL3B1Yi9jcmwvY2FjcmwuY3JsMD+gPaA7hjlodHRwOi8vY2RwMi5wY2EuZGZuLmRl L2Rmbi1jYS1nbG9iYWwtZzIvcHViL2NybC9jYWNybC5jcmwwgdsGCCsGAQUFBwEBBIHOMIHLMDMG CCsGAQUFBzABhidodHRwOi8vb2NzcC5wY2EuZGZuLmRlL09DU1AtU2VydmVyL09DU1AwSQYIKwYB BQUHMAKGPWh0dHA6Ly9jZHAxLnBjYS5kZm4uZGUvZGZuLWNhLWdsb2JhbC1nMi9wdWIvY2FjZXJ0 L2NhY2VydC5jcnQwSQYIKwYBBQUHMAKGPWh0dHA6Ly9jZHAyLnBjYS5kZm4uZGUvZGZuLWNhLWds b2JhbC1nMi9wdWIvY2FjZXJ0L2NhY2VydC5jcnQwDQYJKoZIhvcNAQELBQADggEBAE95rsRSu+9O 2hw2ZEmTXrVZLN52MNXJbOwdXguommCHvIuxkxaNwIUHEF3pVo5Z5UO55oZZaIcFyw2PS9XUhYkN rh4T5Lp6Nqca0b3AfZOBcR16FD3bbUIpPdSQQwkuQCPiXEMam2QjCUfyC3oYja+bmPU2JDiKpunY NJ6/KEp4Yi32U5YEKvkr7ixzl13IKdLoNjO79VCz0iXi9aZ82ixcEli3CXEDxWbo601OTm8abNUX 6QUomu5IDPGAPK65GimsXJbNYN2lhayrgGYKMslQd2ygVm2x5amfrxo1j9I6XvfnnVO1BtJ+e8Cm BPZgGN3+6fE9G6c9IvEhfKUeWZoxggJgMIICXAIBATCBnjCBjTELMAkGA1UEBhMCREUxRTBDBgNV BAoMPFZlcmVpbiB6dXIgRm9lcmRlcnVuZyBlaW5lcyBEZXV0c2NoZW4gRm9yc2NodW5nc25ldHpl cyBlLiBWLjEQMA4GA1UECwwHREZOLVBLSTElMCMGA1UEAwwcREZOLVZlcmVpbiBHbG9iYWwgSXNz dWluZyBDQQIMITwlCcbKdKftcTO4MA0GCWCGSAFlAwQCAQUAoIGTMBgGCSqGSIb3DQEJAzELBgkq hkiG9w0BBwEwHAYJKoZIhvcNAQkFMQ8XDTIwMTAwNjEyNDgyMVowKAYJKoZIhvcNAQkPMRswGTAL BglghkgBZQMEAQIwCgYIKoZIhvcNAwcwLwYJKoZIhvcNAQkEMSIEIN6qNkiTDBgWoLIQqLZr2bEP 9CudEvebZAG9Y2cUhlOyMA0GCSqGSIb3DQEBAQUABIIBAAa1g1v2Gkz3Y6+n2WDO4hHh02dzp4DP ZjGXC2TymblpRh/lHQsl0gX1RP5JIj2an6+49WuSHSDhEIm/LpeTY++huSAy9Ml4XB+OuN0sTo7L y7HnaVsDpDQewTl1sO2qucbI6dNchyR0sVhIuMNEHbrohVeCZVOAgjWhd66KN7ImVvJvir6aR60m +ekCePQLGYf5GDe+AS5K52Nv3ZX98eFAZLa84itpBkozXIvNp1lgwi2zPFtKnJ/1WS8qFFCYNdU4 +Nl5VZjMZ51KxGM/mf9hgQ8pUyGwQlnMR6Hq4trSJWLW6m2Q30nGknEQ7UJ9fhQPArLgrC2JCR00 CaeaqIsAAAAAAAA= --=-=-=--