From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mailgw-02.dd24.net ([193.46.215.43]:60048 "EHLO mailgw-02.dd24.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750830AbbKXE4F (ORCPT ); Mon, 23 Nov 2015 23:56:05 -0500 Received: from mailpolicy-01.live.igb.homer.key-systems.net (mailpolicy-01.live.igb.homer.key-systems.net [192.168.1.26]) by mailgw-02.dd24.net (Postfix) with ESMTP id 2D8D25FB94 for ; Tue, 24 Nov 2015 04:56:03 +0000 (UTC) Received: from mailgw-02.dd24.net ([192.168.1.36]) by mailpolicy-01.live.igb.homer.key-systems.net (mailpolicy-01.live.igb.homer.key-systems.net [192.168.1.25]) (amavisd-new, port 10236) with ESMTP id IDRtuvUoCIwj for ; Tue, 24 Nov 2015 04:56:01 +0000 (UTC) Received: from heisenberg.fritz.box (ppp-93-104-122-99.dynamic.mnet-online.de [93.104.122.99]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mailgw-02.dd24.net (Postfix) with ESMTPSA for ; Tue, 24 Nov 2015 04:56:01 +0000 (UTC) Message-ID: <1448340960.14125.51.camel@scientia.net> Subject: subvols and parents - how? From: Christoph Anton Mitterer To: linux-btrfs@vger.kernel.org Date: Tue, 24 Nov 2015 05:56:00 +0100 Content-Type: multipart/signed; micalg="sha-512"; protocol="application/x-pkcs7-signature"; boundary="=-rZgUxkBendl5IsVKmXMu" Mime-Version: 1.0 Sender: linux-btrfs-owner@vger.kernel.org List-ID: --=-rZgUxkBendl5IsVKmXMu Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Hey. I'd have a, mainly administrative, question. When I use subvolumes than these have always a parent subvolume (except ID5), so I can basically decide between two ways: a) make child subvolumes, e.g. 5 | +-root =C2=A0 (=3Dsubvol, mountpoint /) =C2=A0 +-boot/ =C2=A0 +-root/ =C2=A0 +-lib/ =C2=A0 +-home/ (=3Dsubvolume) and soon on... perhaps the whole thing without the dedicated root- subovlume (although that's probably not so smart, I guess). b) place at least some of the subvolumes directly below the top-level and mount them e.g. via /etc/fstab, e.g. 5 | +-root =C2=A0 (=3Dsubvol, mountpoint /) | +-boot/ | +-root/ | +-lib/ +-home/ (=3Dsubvolume, mountpoint /home) Now I wondered whether this has any technical implications, but neither the wiki, nor the manpages seem to explain a lot here. The "differences", AFAIU, are the follows: - When I mount a given subvolume,.. it's childs are automatically=C2=A0 =C2=A0 "there". =C2=A0 Whereas when I don't have them as childs (as in (b)) I must of =C2=A0 course mount them somehow manually. - Analogously for umounting. - I can move existing subvols to higher/lower levels, and the parent =C2=A0 IDs will change accordingly. So basically it makes no difference, right? Or is there anything more technical going on? E.g. with the ref-links or so? Right now, there are, AFAIK, neither recursive snapshots (and especially not atomic ones) nor recursive send/receive, right? If that should ever be implemented, would I perhaps have problems with=C2= =A0 (a) or (b)? Thanks, Chris. btw, for a developer: $ btrfs subvolume list /mnt/ -pacguqt ID=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0gen=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0cgen= =C2=A0=C2=A0=C2=A0=C2=A0parent=C2=A0=C2=A0top level=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0=C2=A0parent_uuid=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0uuid=C2=A0=C2=A0= =C2=A0=C2=A0path=C2=A0=C2=A0=C2=A0=C2=A0 --=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0---=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0----= =C2=A0=C2=A0=C2=A0=C2=A0------=C2=A0=C2=A0---------=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0=C2=A0-----------=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0----=C2=A0=C2=A0= =C2=A0=C2=A0----=C2=A0=C2=A0=C2=A0=C2=A0 257=C2=A0=C2=A0=C2=A0=C2=A0=C2=A016=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A08=C2= =A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A05=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A05=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0=C2=A0-=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A064f8a= 75b-5cb5-6e4d-9f30-d45fe3d9e060=C2=A0=C2=A0=C2=A0=C2=A0/root There seem to be some colum mis-aglinment issues in the output =3D) btrfsprogs 4.3 --=-rZgUxkBendl5IsVKmXMu Content-Type: application/x-pkcs7-signature; name="smime.p7s" Content-Disposition: attachment; filename="smime.p7s" Content-Transfer-Encoding: base64 MIAGCSqGSIb3DQEHAqCAMIACAQExDzANBglghkgBZQMEAgMFADCABgkqhkiG9w0BBwEAAKCCEZIw ggW/MIIDp6ADAgECAgMCOakwDQYJKoZIhvcNAQENBQAwVDEUMBIGA1UEChMLQ0FjZXJ0IEluYy4x HjAcBgNVBAsTFWh0dHA6Ly93d3cuQ0FjZXJ0Lm9yZzEcMBoGA1UEAxMTQ0FjZXJ0IENsYXNzIDMg Um9vdDAeFw0xNDA2MTIxNjM2MThaFw0xNjA2MTExNjM2MThaMHwxITAfBgNVBAMTGENocmlzdG9w aCBBbnRvbiBNaXR0ZXJlcjEkMCIGCSqGSIb3DQEJARYVY2FsZXN0eW9Ac2NpZW50aWEubmV0MTEw LwYJKoZIhvcNAQkBFiJtYWlsQGNocmlzdG9waC5hbnRvbi5taXR0ZXJlci5uYW1lMIIBIjANBgkq hkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA4phP/j9vT9dZT+k3ffHxvRWMOuzBnu5O3Fl4y2+WL7pL rfLiEhWzGXhHvjSqpt4vCNSdqy43453nnu8+hMb+uEtqSIL1AHU5eLhuDNVN9S4bt9E7nA2WKYBU LCUi/xCD/GL7ToyJNwhrhzcCZ7pXSc3xVqFoC4f6weU9ExhoEZQNRpTM0BFCOi4fRxvKFNnUYgjK hqy0Ta5H0Xx86mAp0Q4dxoD7mhI5iTF6TRkUheELxF24JCuAf04M89Cwft6DRH1FpJ3yvgW2B5U5 aFSL4ZnF4N/wyCB7Dkm1rQ7RCAvw5btkf0VdPnU7ccDCx8HEc2nxK/lbCjrznvh3sa1CCwIDAQAB o4IBcDCCAWwwDAYDVR0TAQH/BAIwADBWBglghkgBhvhCAQ0ESRZHVG8gZ2V0IHlvdXIgb3duIGNl cnRpZmljYXRlIGZvciBGUkVFIGhlYWQgb3ZlciB0byBodHRwOi8vd3d3LkNBY2VydC5vcmcwDgYD VR0PAQH/BAQDAgOoMEAGA1UdJQQ5MDcGCCsGAQUFBwMEBggrBgEFBQcDAgYKKwYBBAGCNwoDBAYK KwYBBAGCNwoDAwYJYIZIAYb4QgQBMDIGCCsGAQUFBwEBBCYwJDAiBggrBgEFBQcwAYYWaHR0cDov L29jc3AuY2FjZXJ0Lm9yZzA4BgNVHR8EMTAvMC2gK6AphidodHRwOi8vY3JsLmNhY2VydC5vcmcv Y2xhc3MzLXJldm9rZS5jcmwwRAYDVR0RBD0wO4EVY2FsZXN0eW9Ac2NpZW50aWEubmV0gSJtYWls QGNocmlzdG9waC5hbnRvbi5taXR0ZXJlci5uYW1lMA0GCSqGSIb3DQEBDQUAA4ICAQBefctiLgGl e5baspuozyA4k7Up7SVhGHbif6pQfoFc/9Thx9GXnYpX+U64PMyWBfWwHZIy52Vg0RVkvPi1t6mi GyBfoSpC6ooR0bKWtUIogw/ymqKWlTLVR8kbLqRmRk4juMtCXG2K3yMygX/rjkuUSuFj2Bjpkmzg CtMojbUMYbszePmhQ7DJ62YEdtKpcjN94QAsI5GWlIAbs3KJazAcaNCRJeXCLcUMchyKHJA+NXH5 az/ekBxBMBzJP2An20PP88UI4JW18z31KiG9UVGa2uO4l4aWgVe2GnhNEdCD/o48msJEWKAt5vl2 yMqr7ihmNPocU2+/FW0xPe/vftdOTD9pgXdSGf4prdD+23q2YvpalOCzr2p8yCJZNVBPMxAP4mL0 3OEktXza4wohqAmceXKfGUNwRGBaPvtIGnPrpLhCQ+2YJDg8g1UEsk23bKyZlJWeKJyVqOBsDJmj aBsN/qKhQFnav+zQdqGhMeaSisF/53mD3gyVYg2JRl18apgGbg32kyLmomqa0JbhnY3Dc3FVtZfe +P+s2Cyep3pVKvFer2llRoGm8TwraG5Yhyx8Oq/1qETpstjbURJOVBLDCV4AjOEUj0ZnE/tEo/DK yexgGaViNvjp+IZdFdJhYmsVjw4Q3vG7O0pfsLiYEyQjeDgjNEWDfa5/MufPywIfxzCCBb8wggOn oAMCAQICAwI5qTANBgkqhkiG9w0BAQ0FADBUMRQwEgYDVQQKEwtDQWNlcnQgSW5jLjEeMBwGA1UE CxMVaHR0cDovL3d3dy5DQWNlcnQub3JnMRwwGgYDVQQDExNDQWNlcnQgQ2xhc3MgMyBSb290MB4X DTE0MDYxMjE2MzYxOFoXDTE2MDYxMTE2MzYxOFowfDEhMB8GA1UEAxMYQ2hyaXN0b3BoIEFudG9u IE1pdHRlcmVyMSQwIgYJKoZIhvcNAQkBFhVjYWxlc3R5b0BzY2llbnRpYS5uZXQxMTAvBgkqhkiG 9w0BCQEWIm1haWxAY2hyaXN0b3BoLmFudG9uLm1pdHRlcmVyLm5hbWUwggEiMA0GCSqGSIb3DQEB AQUAA4IBDwAwggEKAoIBAQDimE/+P29P11lP6Td98fG9FYw67MGe7k7cWXjLb5Yvukut8uISFbMZ eEe+NKqm3i8I1J2rLjfjneee7z6Exv64S2pIgvUAdTl4uG4M1U31Lhu30TucDZYpgFQsJSL/EIP8 YvtOjIk3CGuHNwJnuldJzfFWoWgLh/rB5T0TGGgRlA1GlMzQEUI6Lh9HG8oU2dRiCMqGrLRNrkfR fHzqYCnRDh3GgPuaEjmJMXpNGRSF4QvEXbgkK4B/Tgzz0LB+3oNEfUWknfK+BbYHlTloVIvhmcXg 3/DIIHsOSbWtDtEIC/Dlu2R/RV0+dTtxwMLHwcRzafEr+VsKOvOe+HexrUILAgMBAAGjggFwMIIB bDAMBgNVHRMBAf8EAjAAMFYGCWCGSAGG+EIBDQRJFkdUbyBnZXQgeW91ciBvd24gY2VydGlmaWNh dGUgZm9yIEZSRUUgaGVhZCBvdmVyIHRvIGh0dHA6Ly93d3cuQ0FjZXJ0Lm9yZzAOBgNVHQ8BAf8E BAMCA6gwQAYDVR0lBDkwNwYIKwYBBQUHAwQGCCsGAQUFBwMCBgorBgEEAYI3CgMEBgorBgEEAYI3 CgMDBglghkgBhvhCBAEwMgYIKwYBBQUHAQEEJjAkMCIGCCsGAQUFBzABhhZodHRwOi8vb2NzcC5j YWNlcnQub3JnMDgGA1UdHwQxMC8wLaAroCmGJ2h0dHA6Ly9jcmwuY2FjZXJ0Lm9yZy9jbGFzczMt cmV2b2tlLmNybDBEBgNVHREEPTA7gRVjYWxlc3R5b0BzY2llbnRpYS5uZXSBIm1haWxAY2hyaXN0 b3BoLmFudG9uLm1pdHRlcmVyLm5hbWUwDQYJKoZIhvcNAQENBQADggIBAF59y2IuAaV7ltqym6jP IDiTtSntJWEYduJ/qlB+gVz/1OHH0Zedilf5Trg8zJYF9bAdkjLnZWDRFWS8+LW3qaIbIF+hKkLq ihHRspa1QiiDD/KaopaVMtVHyRsupGZGTiO4y0JcbYrfIzKBf+uOS5RK4WPYGOmSbOAK0yiNtQxh uzN4+aFDsMnrZgR20qlyM33hACwjkZaUgBuzcolrMBxo0JEl5cItxQxyHIockD41cflrP96QHEEw HMk/YCfbQ8/zxQjglbXzPfUqIb1RUZra47iXhpaBV7YaeE0R0IP+jjyawkRYoC3m+XbIyqvuKGY0 +hxTb78VbTE97+9+105MP2mBd1IZ/imt0P7berZi+lqU4LOvanzIIlk1UE8zEA/iYvTc4SS1fNrj CiGoCZx5cp8ZQ3BEYFo++0gac+ukuEJD7ZgkODyDVQSyTbdsrJmUlZ4onJWo4GwMmaNoGw3+oqFA Wdq/7NB2oaEx5pKKwX/neYPeDJViDYlGXXxqmAZuDfaTIuaiaprQluGdjcNzcVW1l974/6zYLJ6n elUq8V6vaWVGgabxPCtobliHLHw6r/WoROmy2NtREk5UEsMJXgCM4RSPRmcT+0Sj8MrJ7GAZpWI2 +On4hl0V0mFiaxWPDhDe8bs7Sl+wuJgTJCN4OCM0RYN9rn8y58/LAh/HMIIGCDCCA/CgAwIBAgIB ATANBgkqhkiG9w0BAQQFADB5MRAwDgYDVQQKEwdSb290IENBMR4wHAYDVQQLExVodHRwOi8vd3d3 LmNhY2VydC5vcmcxIjAgBgNVBAMTGUNBIENlcnQgU2lnbmluZyBBdXRob3JpdHkxITAfBgkqhkiG 9w0BCQEWEnN1cHBvcnRAY2FjZXJ0Lm9yZzAeFw0wNTEwMTQwNzM2NTVaFw0zMzAzMjgwNzM2NTVa MFQxFDASBgNVBAoTC0NBY2VydCBJbmMuMR4wHAYDVQQLExVodHRwOi8vd3d3LkNBY2VydC5vcmcx HDAaBgNVBAMTE0NBY2VydCBDbGFzcyAzIFJvb3QwggIiMA0GCSqGSIb3DQEBAQUAA4ICDwAwggIK AoICAQCrSTURSHzSJn5TlM9Dqd0o10Iqi/OHeBlYfA+e2ol94fvrcpANdKGWZKufoCSZc9riVXbH F3v1BKxGuMO+f2SNEGwk82GcwPKQ+lHm9WkBY8MPVuJKQs/iRIwlKKjFeQl9RrmK8+nzNCkIReQc n8uUBByBqBSzmGXEQ+xOgo0J0b2qW42S0OzekMV/CsLj6+YxWl50PpczWejDAz1gM7/30W9HxM3u YoNSbi4ImqTZFRiRpoWSR7CuSOtttyHshRpocjWr//AQXcD0lKdq1TuSfkyQBX6TwSyLpI5idBVx bgtxA+qvFTia1NIFcm+M+SvrWnIl+TlG43IbPgTDZCciECqKT1inA62+tC4T7V2qSNfVfdQqe1z6 RgRQ5MwOQluM7dvyz/yWk+DbETZUYjQ4jwxgmzuXVjit89Jbi6Bb6k6WuHzX1aCGcEDTkSm3ojyt 9Yy7zxqSiuQ0e8DYbF/pCsLDpyCaWt8sXVJcukfVm+8kKHA4IC/VfynAskEDaJLM4JzMl0tF7zoQ CqtwOpiVcK01seqFK6QcgCExqa5geoAmSAC4AcCTY1UikTxW56/bOiXzjzFU6iaLgVn5odFTEcV7 nQP2dBHgbbEsPyyGkZlxmqZ3izRg0RS0LKydr4wQ05/EavhvE/xzWfdmQnQeiuP43NJvmJzLR5iV QAX76QIDAQABo4G/MIG8MA8GA1UdEwEB/wQFMAMBAf8wXQYIKwYBBQUHAQEEUTBPMCMGCCsGAQUF BzABhhdodHRwOi8vb2NzcC5DQWNlcnQub3JnLzAoBggrBgEFBQcwAoYcaHR0cDovL3d3dy5DQWNl cnQub3JnL2NhLmNydDBKBgNVHSAEQzBBMD8GCCsGAQQBgZBKMDMwMQYIKwYBBQUHAgEWJWh0dHA6 Ly93d3cuQ0FjZXJ0Lm9yZy9pbmRleC5waHA/aWQ9MTAwDQYJKoZIhvcNAQEEBQADggIBAH8IiKHa GlBJ2on7oQhy84r3HsQ6tHlbIDCxRd7CXdNlafHCXVRUPIVfuXtCkcKZ/RtRm6tGpaEQU55tiKxz biwzpvD0nuB1wT6IRanhZkP+VlrRekF490DaSjrxC1uluxYG5sLnk7mFTZdPsR44Q4Dvmw2M77in YACHV30eRBzLI++bPJmdr7UpHEV5FpZNJ23xHGzDwlVks7wU4vOkHx4y/CcVBc/dLq4+gmF78CEQ GPZE6lM5+dzQmiDgxrvgu1pPxJnIB721vaLbLmINQjRBvP+LivVRIqqIMADisNS8vmW61QNXeZvo 3MhN+FDtkaVSKKKs+zZYPumUK5FQhxvWXtaMzPcPEAxSTtAWYeXlCmy/F8dyRlecmPVsYGN6b165 Ti/Iubm7aoW8mA3t+T6XhDSUrgCvoeXnkm5OvfPi2RSLXNLrAWygF6UtEOucekq9ve7O/e0iQKtw OIj1CodqwqsFYMlIBdpTwd5Ed2qz8zw87YC8pjhKKSRf/lk7myV6VmMAZLldpGJ9VzZPrYPvH5JT oI53V93lYRE9IwCQTDz6o2CTBKOvNfYOao9PSmCnhQVsRqGP9Md246FZV/dxssRuFFxtbUFm3xuT sdQAw+7Lzzw9IYCpX2Nl/N3gX6T0K/CFcUHUZyX7GrGXrtaZghNB0m6lG5kngOcLqagAMYIC7TCC AukCAQEwWzBUMRQwEgYDVQQKEwtDQWNlcnQgSW5jLjEeMBwGA1UECxMVaHR0cDovL3d3dy5DQWNl cnQub3JnMRwwGgYDVQQDExNDQWNlcnQgQ2xhc3MgMyBSb290AgMCOakwDQYJYIZIAWUDBAIDBQCg ggFjMBgGCSqGSIb3DQEJAzELBgkqhkiG9w0BBwEwHAYJKoZIhvcNAQkFMQ8XDTE1MTEyNDA0NTYw MFowTwYJKoZIhvcNAQkEMUIEQITPLVDEmW7e0+ZmXskeZ8eTjKSRvqK+tpNAPIECLljHXxN7fGCj KkljSS3drND9/kWvq31TwDbG+K3FyGgNQ40wagYJKwYBBAGCNxAEMV0wWzBUMRQwEgYDVQQKEwtD QWNlcnQgSW5jLjEeMBwGA1UECxMVaHR0cDovL3d3dy5DQWNlcnQub3JnMRwwGgYDVQQDExNDQWNl cnQgQ2xhc3MgMyBSb290AgMCOakwbAYLKoZIhvcNAQkQAgsxXaBbMFQxFDASBgNVBAoTC0NBY2Vy dCBJbmMuMR4wHAYDVQQLExVodHRwOi8vd3d3LkNBY2VydC5vcmcxHDAaBgNVBAMTE0NBY2VydCBD bGFzcyAzIFJvb3QCAwI5qTANBgkqhkiG9w0BAQEFAASCAQBIds+YLEnFTmIMiDlc13wjuIhplBdC BlmdOWSUm52Ow4KpHePjQURFBfE0IkrSBzJmwUwNN52rBxqavxBMEfASj3YKHG0I/zCzorTNzQ1n NRLiws0h6/YHldhsfXcg+kh9Q4jSSFiCrxSXON/afbHEv0sR2pSMXUYIgPuLylUDyoUq6xS88dEP wg3KnBxT2D5Q1xFz23LECVWnjIQfMAFOj/nyt5FgfGZyNyZBqqr3wjB3VSPoZNayHS5jas233KD6 U7j2oV4DeEmQ7B7p3VxChjmJMLuBCIb/YsJ0fT51K8w8PcmkZj6u//OFv6Pnq3tQgkFo04PWkdOs h7TdXxArAAAAAAAA --=-rZgUxkBendl5IsVKmXMu--