Re: [RFC ONLY 0/8] btrfs: introduce raid-stripe-tree

[Nikolay Borisov <nborisov@suse.com>]

On 16.05.22 г. 17:31 ч., Johannes Thumshirn wrote:
> Introduce a raid-stripe-tree to record writes in a RAID environment.
> 
> In essence this adds another address translation layer between the logical
> and the physical addresses in btrfs and is designed to close two gaps. The
> first is the ominous RAID-write-hole we suffer from with RAID5/6 and the
> second one is the inability of doing RAID with zoned block devices due to the
> constraints we have with REQ_OP_ZONE_APPEND writes.
> 
> Thsi is an RFC/PoC only which just shows how the code will look like for a
> zoned RAID1. Its sole purpose is to facilitate design reviews and is not
> intended to be merged yet. Or if merged to be used on an actual file-system.
> 
> Johannes Thumshirn (8):
>    btrfs: add raid stripe tree definitions
>    btrfs: move btrfs_io_context to volumes.h
>    btrfs: read raid-stripe-tree from disk
>    btrfs: add boilerplate code to insert raid extent
>    btrfs: add code to delete raid extent
>    btrfs: add code to read raid extent
>    btrfs: zoned: allow zoned RAID1
>    btrfs: add raid stripe tree pretty printer
> 
>   fs/btrfs/Makefile               |   2 +-
>   fs/btrfs/ctree.c                |   1 +
>   fs/btrfs/ctree.h                |  29 ++++
>   fs/btrfs/disk-io.c              |  12 ++
>   fs/btrfs/extent-tree.c          |   9 ++
>   fs/btrfs/file.c                 |   1 -
>   fs/btrfs/print-tree.c           |  21 +++
>   fs/btrfs/raid-stripe-tree.c     | 251 ++++++++++++++++++++++++++++++++
>   fs/btrfs/raid-stripe-tree.h     |  39 +++++
>   fs/btrfs/volumes.c              |  44 +++++-
>   fs/btrfs/volumes.h              |  93 ++++++------
>   fs/btrfs/zoned.c                |  39 +++++
>   include/uapi/linux/btrfs.h      |   1 +
>   include/uapi/linux/btrfs_tree.h |  17 +++
>   14 files changed, 509 insertions(+), 50 deletions(-)
>   create mode 100644 fs/btrfs/raid-stripe-tree.c
>   create mode 100644 fs/btrfs/raid-stripe-tree.h
> 


So if we choose to go with raid stripe tree this means we won't need the 
raid56j code that Qu is working on ? So it's important that these two 
work streams are synced so we don't duplicate effort, right?