On Thu, Aug 16, 2012 at 09:20:00PM -0700, james northrup wrote: > dunno if this thread is dead, but im inclined to patch in cp --reflink > to "fdupes" prog. It currently does provide a poor-man's dedupe via > md5sum and hardlink, or delete. > > all the better if the distro-kernels can backport cross-snapshot > reflinks sooner than later. So, I'd love for cp --reflink to bring back a deleted VM (huge file) from a snapshot back to trunk without duplicating it. But how would fdupes help? I can't hardlink between two snapshots, can I?
gandalfthegreat:/mnt/btrfs_pool1# ln usr_weekly_20120812_00\:02\:01/svn-commit.tmp usr/test ln: failed to create hard link `usr/test' => `usr_weekly_20120812_00:02:01/svn-commit.tmp': Invalid cross-device link So, is there anything user space can do without kernel support? Marc > On Sun, Apr 29, 2012 at 1:05 PM, Norbert Scheibner <s...@gmx.net> wrote: > > Am 29.04.2012, 01:53 Uhr, schrieb Hubert Kario <h...@qbs.com.pl>: > > > > > >> On Sunday 01 of April 2012 11:42:23 Jérôme Poulin wrote: > >>> > >>> On Sun, Apr 1, 2012 at 11:27 AM, Norbert Scheibner <s...@gmx.net> wrote: > >>> > Some users tested this patch successfully for week,s or months in 2 or > >>> > 3 > >>> > kernel versions since then, true? > >>> If this feature must be implented in VFS in another patch, why not > >>> just activate what works and make the future patch disable it again? > >> > >> > >> Why would (should) it be impleemented in VFS? reflink copy is completely > >> different from normal copy and hard link. > > > > > > I wouldn't make a VFS issue out of that. That should be another discussion. > > > > But: > > > >> Subvolumes in btrfs are barriers *only* in btrfs and not visible in VFS. > > > > > > That is just a bug in my opinion, so it should work anyway, but to look at > > it from VFS point of view is strengthening me in wanting the outstanding > > patches integrated, as this feature could be supported by VFS in the future. > > > > > >> IMHO it's strictly btrfs business and not supporting reflink copy between > >> arbitrary directories is a bug. > > > > > > I don't know exactly, but I think ZFS is another candidate for "cp > > --reflink". For some of the log-structured filesystems this could be usefull > > too, but I don't know if some of them already supports this or plan to > > support this in the future. > > > > Greetings > > Norbert > > > > -- > > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > > the body of a message to majord...@vger.kernel.org > > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majord...@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- "A mouse is a device used to point at the xterm you want to type in" - A.S.R. Microsoft is to operating systems .... .... what McDonalds is to gourmet cooking Home page: http://marc.merlins.org/ -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
