Re: [PATCH 0/4] More split-brain fixes for metadata uuid feature

[David Sterba <dsterba@suse.cz>]

On Fri, Jan 10, 2020 at 02:11:31PM +0200, Nikolay Borisov wrote:
> Here are 4 patches which fix a newly found split-brain scenario in the
> METADATA_UUID_INCOMPAT code. They are mostly the identical with Su's
> original submission but I have reworked the changelogs and some function
> names. Hence, I retained his authorship of the patches.
> 
> First 2 patches factor out some code with the hopes of making find_fisd a bit
> more readable and simplifying the myriad of nested 'if' in device_list_add.
> 
> Patch 3 extends find_fsid_changed to handle the case where a disk with
> METADATA_UUID_INCOMPAT and FSID_CHANGING_IN_PROGRESS is scanned after a disk
> which has successfully been switched to FSID == METADATA_UUID state and has
> created btrfs_fs_devices.
> 
> Patch 4 handles the counterpart situation - a fully switched disk is scanned
> after one which has had METADATA_UUID_INCOMPAT and FSID_CHANGING_IN_PROGRESS
> set.
> 
> This series should be applied to stable branches following 5.0 when the
> metadata_uuid feature got introduced.
> 
> This patchset was tested with btrfs-progs' misc 034-metadata-uuid test and a full
> xfstest run with no regressions. I will also be sending an improvement to the
> test case which exercises the newly added code.
> 
>   btrfs: Call find_fsid from find_fsid_inprogress
>   btrfs: Factor out metadata_uuid code from find_fsid.
>   btrfs: Handle another split brain scenario with metadata uuid feature
>   btrfs: Fix split-brain handling when changing FSID to metadata uuid

I'm adding it to for-next, thanks.