From: Alex Lyakas <alex.btrfs@zadarastorage.com>
To: junlion@tormail.org
Cc: linux-btrfs@vger.kernel.org
Subject: Re: Incremental btrfs receive in opposite direction fails
Date: Sat, 29 Dec 2012 15:00:48 +0200 [thread overview]
Message-ID: <CAOcd+r3OjBAGbRN-cSbL7tQP=tTRYakZO3fm9gA_oqSz6KXuYw@mail.gmail.com> (raw)
In-Reply-To: <1ToibV-0001fD-SN@internal.tormail.org>
Hi,
On Sat, Dec 29, 2012 at 12:42 AM, <junlion@tormail.org> wrote:
> Hi everyone!
>
> (I use kernel 3.7.1 and mason/btrfs-progs.git head + the receive
> lchown patch [1]. Is there a more up to date btrfs-progs repo for
> send/receive enthusiasts?)
There is no special repo, but you may want, in addition to the patch
you mentioned, apply this one as well:
https://patchwork.kernel.org/patch/1604391/
Whether you need it or not depends on how your subvolumes are
organized in a file tree.
>
> What I'm trying is basically:
>
> # Transfer a snapshot of my old system from a backup to the new system
> btrfs send /mnt/bak/.snap | btrfs receive / # OK
>
> # Merge the old system's files with the new system's files
> btrfs subvolume snapshot /.snap /.snap-merge # OK
> mkdir /.snap-merge/.old # OK
> mv /.snap-merge/* /.snap-merge/.old # OK
> cp -a --reflink /* /.snap-merge # OK
> btrfs subvolume snapshot -r /.snap-merge /.snap-merge-done # OK
>
> # Incrementally transfer the merged files back to the backup drive
> btrfs send -p /.snap /.snap-merge-done | btrfs receive -p /mnt/bak
>
> The last step fails due to the changed direction of the transfer.
> "ERROR: could not find parent subvolume". It seems like btrfs receive
> cannot find the parent/clone source because it is searching for its UUID
> only by looking through the /mnt/bak snapshots' received_uuid fields.
>
> Is there a way for me to directly change the received_uuid of
> /mnt/bak/.snap to make it identical to the UUID of /.snap? This looks
> like the easiest way if I only need to do it once.
There is no implemented way, but since you debugged this far, you can
put up some code that sends BTRFS_IOC_SET_RECEIVED_SUBVOL, which is
the one setting the received_uuid (and some other small stuff, please
check the kernel code for it).
Thanks,
Alex.
>
> [1] https://patchwork.kernel.org/patch/1606091/
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next prev parent reply other threads:[~2012-12-29 13:00 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-28 22:42 Incremental btrfs receive in opposite direction fails junlion
2012-12-29 13:00 ` Alex Lyakas [this message]
2012-12-30 6:40 ` junlion
2013-01-02 16:57 ` Jan Schmidt
2013-01-02 20:56 ` Jun Lion
[not found] ` <20130102205351.GA2242@localhost>
2013-01-02 22:19 ` junlion
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