[dm-devel] [git pull] device mapper fix for 4.18-rc6
teigland at redhat.com
Tue Jul 24 15:30:55 UTC 2018
On Tue, Jul 24, 2018 at 11:18:54AM -0400, Mikulas Patocka wrote:
> > I hold it to be a "fix" because it was an embarassing oversight on my
> > part. Without this, userspace support cannot be properly added. LVM2
> > developers raised their inability to put their metadata anywhere and I
> > was like "oh shit".
> This is not oversight.
> It was originally planned that the dm-writecache target would use lvm
> metadata just like the dm-cache target - if it were implemented this way,
> no "offset" argument would be needed. But David Teigland who was given the
> task to implement dm-writecache support in lvm refused to do it this way
> and he insists that he must put some of his own metadata at the beginning
> of the cache device before the superblock.
> So this patch is needed because of him.
Mikulas, an offset would have been useful while I was experimenting with
dm-writecache. I don't actually use or need the offset in lvm. I don't
think it's a bad idea, but I don't care.
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