From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from lists.gentoo.org (pigeon.gentoo.org [208.92.234.80]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by finch.gentoo.org (Postfix) with ESMTPS id EFF661382C5 for ; Wed, 24 Mar 2021 17:10:19 +0000 (UTC) Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id C6391E087A; Wed, 24 Mar 2021 17:10:16 +0000 (UTC) Received: from mail-ot1-f49.google.com (mail-ot1-f49.google.com [209.85.210.49]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by pigeon.gentoo.org (Postfix) with ESMTPS id 7120EE086E for ; Wed, 24 Mar 2021 17:10:16 +0000 (UTC) Received: by mail-ot1-f49.google.com with SMTP id k14-20020a9d7dce0000b02901b866632f29so23714492otn.1 for ; Wed, 24 Mar 2021 10:10:16 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:content-transfer-encoding; bh=K595ylgOAx2B7TXUqIA9qGgSu691bgXmccxIOlgTwsI=; b=AdgU04zp9l3K/uOwAvOjfQVVKOhaMXxdU2AxeJahjMYNDMHVYv2q4i1AlW7NANHd0Y cUubBuv+SrQq+lwUdP6Ls53L2Ruvp7JWesA957KyCZEB6Gd4oOxj1P9GBp3I4qsys5h6 2LD7ly1zw+FuEit3g18t0Zjq3y6KELZNZKM1/7mmlaSrz2ijazH7idXahX0dJj8PXWqE LebhFA+0BI38mkT/4/WP1duXm951SjBhWkoXFUyd2TEE6JeMLNW5ppRS6h8jkEiyXOdv X5XbR4kQsmRl+soWiho7IlwtCrrE9pOJltkZyv1m8KXJGCEzI+m06HeTMV9swALlE/lU LKhg== X-Gm-Message-State: AOAM530bi6cVedFBdbe2m4WA96OgHiwS2imCx3jh6Zg60VK6pu+TPrFZ M55mUUJgUoF77h2uNON8xEHQk2apnQH4/9G1/KvGS0ciwaQ= X-Google-Smtp-Source: ABdhPJwN0oH3709pR9qvAMuIl2/QH90t9VsMgvlhsreyxSAJbpGRue37BE0JctKY+SVNHjtvgIHYMe9GjotqqM7MZ2I= X-Received: by 2002:a05:6830:1513:: with SMTP id k19mr3851422otp.51.1616605815198; Wed, 24 Mar 2021 10:10:15 -0700 (PDT) Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-dev@lists.gentoo.org Reply-to: gentoo-dev@lists.gentoo.org X-Auto-Response-Suppress: DR, RN, NRN, OOF, AutoReply MIME-Version: 1.0 References: In-Reply-To: From: Rich Freeman Date: Wed, 24 Mar 2021 13:09:52 -0400 Message-ID: Subject: Re: [gentoo-dev] rfc: usrmerge script To: gentoo-dev Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Archives-Salt: 4bdf9576-1ed2-46bf-b71c-3935c60edcbd X-Archives-Hash: fcff0ba84875afc6b052aad022f6bf00 On Wed, Mar 24, 2021 at 11:09 AM William Hubbs wrote: > > On Wed, Mar 24, 2021 at 08:48:41AM +0100, Micha=C5=82 G=C3=B3rny wrote: > > > > What really can help is reflinking on filesystems supporting that. > > What really can help is more info instead of being terse like this. > Which filesystems support it? > According to Google right now: Btrfs, CIFS, NFS 4.2, OCFS2, overlayfs, and = XFS Lizardfs ought to, but doesn't currently. zfs does not because clones only are supported at the dataset level. In any case, if you're using coreutils cp to do the copy, just pass --reflink=3Dauto. Honestly, I have no idea why this isn't the default behavior. Who wouldn't want instant copy operations that consume zero space (aside from metdata)? If you're doing this in C or some other language you would need to see if they have a library call to do it easily - see man ioctl_ficlone. --=20 Rich