Re: How to change/fix 'Received UUID'

[Andrei Borzenkov <arvidjaar@gmail.com>]

05.03.2018 19:16, Marc MERLIN пишет:
> Howdy,
> 
> I did a bunch of copies and moving around subvolumes between disks and
> at some point, I did a snapshot dir1/Win_ro.20180205_21:18:31 dir2/Win_ro.20180205_21:18:31
> 
> As a result, I lost the ro flag, and apparently 'Received UUID' which is
> now preventing me from restarting the btrfs send/receive.
> 
> I changed the snapshot back to 'ro' but that's not enough:
> 
> Source:
>         Name:                   Win_ro.20180205_21:18:31
>         UUID:                   23ccf2bd-f494-e348-b34e-1f28486b2540
>         Parent UUID:            -
>         Received UUID:          3cc327e1-358f-284e-92e2-4e4fde92b16f
>         Creation time:          2018-02-15 20:14:42 -0800
>         Subvolume ID:           964
>         Generation:             4062
>         Gen at creation:        459
>         Parent ID:              5
>         Top level ID:           5
>         Flags:                  readonly
> 
> Dest:
>         Name:                   Win_ro.20180205_21:18:31
>         UUID:                   a1e8777c-c52b-af4e-9ce2-45ca4d4d2df8
>         Parent UUID:            -
>         Received UUID:          -
>         Creation time:          2018-02-17 22:20:25 -0800
>         Subvolume ID:           94826
>         Generation:             250714
>         Gen at creation:        250540
>         Parent ID:              89160
>         Top level ID:           89160
>         Flags:                  readonly
> 
> If I absolutely know that the data is the same on both sides, how do I
> either
> 1) force back in a 'Received UUID' value on the destination

I suppose the most simple is to write small program that does it using
BTRFS_IOC_SET_RECEIVED_SUBVOL.

> 2) force a btrfs receive to work despite the lack of matching 'Received
> UUID' 
> 
> Yes, I could discard and start over, but my 2nd such subvolume is 8TB,
> so I'd really rather not :)
> 
> Any ideas?
> 
> Thanks,
> Marc
>