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Date:   Wed, 19 Apr 2023 10:47:34 -0400
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Subject: Re: [PATCH 0/8 v3] nfs-utils: Improving NFS re-export wrt. crossmnt
To:     Richard Weinberger <richard@nod.at>, linux-nfs@vger.kernel.org
Cc:     david@sigma-star.at, david.oberhollenzer@sigma-star.at,
        luis.turcitu@appsbroker.com, david.young@appsbroker.com,
        trond.myklebust@hammerspace.com, anna.schumaker@netapp.com,
        chris.chilvers@appsbroker.com
References: <20230418093350.4550-1-richard@nod.at>
Content-Language: en-US
From:   Steve Dickson <steved@redhat.com>
In-Reply-To: <20230418093350.4550-1-richard@nod.at>
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On 4/18/23 5:33 AM, Richard Weinberger wrote:
> After a longer hiatus I'm sending the next iteration of my re-export
> improvement patch series. While the kernel side is upstream since v6.2,
> the nfs-utils parts are still missing.
> This patch series aims to solve this.
> 
> The core idea is adding new export option, reeport=
> Using reexport= it is possible to mark an export entry in the exports
> file explicitly as NFS re-export and select a strategy on how unique
> identifiers should be provided. This makes the crossmnt feature work
> in the re-export case.
> Currently two strategies are supported, "auto-fsidnum" and
> "predefined-fsidnum".
> 
> In my earlier series a sqlite database was mandatory to keep track of
> generated fsids.
> This series follows a different approach, instead of directly using
> sqlite in all nfs-utils components (linking libsqlite), a new deamon
> manages the database, fsidd.
> fsidd offers a simple (but stupid?) text based interface over a unix domain
> socket which can be queried by mountd, exportfs, etc. for fsidnums.
> The main idea behind fsidd is allowing users to implement their own
> fsidd which keeps global state across load balancers.
> I'm still not happy with fsidd, there is room for improvement but first
> I'd like to know whether you like or hate this approach.
> 
> A typical export entry on a re-exporting server looks like:
>          /nfs *(rw,no_root_squash,no_subtree_check,crossmnt,reexport=auto-fsidnum)
> reexport=auto-fsidnum will automatically assign an fsid= to /nfs and all
> uncovered subvolumes.
> 
> Changes since v2, https://lore.kernel.org/linux-nfs/20230404111308.23465-1-richard@nod.at/
> 	- Split patch series
> 	- Add improved fsidd system unit file
> 	- Rebased to nfs-utils master as of today
> 	- Dropped init code from exportd
> 
> Changes since v1, https://lore.kernel.org/linux-nfs/20220502085045.13038-1-richard@nod.at/
>          - Factor out Sqlite and put it into a daemon
>          - Add fsidd
>          - Basically re-implemented the patch series
>          - Lot's of fixes (e.g. nfs v4 root export)
> 
> 
> Richard Weinberger (8):
>    Add reexport helper library
>    Implement reexport= export option
>    export: Wireup reexport mechanism
>    export: Uncover NFS subvolume after reboot
>    exports.man: Document reexport= option
>    reexport: Add sqlite backend
>    export: Add fsidd
>    Add fsid systemd service file
> 
>   configure.ac                        |   1 +
>   support/Makefile.am                 |   2 +-
>   support/export/Makefile.am          |   2 +
>   support/export/cache.c              |  74 ++++++-
>   support/export/export.c             |  20 ++
>   support/include/nfslib.h            |   1 +
>   support/nfs/Makefile.am             |   1 +
>   support/nfs/exports.c               |  62 ++++++
>   support/reexport/Makefile.am        |  18 ++
>   support/reexport/backend_sqlite.c   | 267 +++++++++++++++++++++++
>   support/reexport/fsidd.c            | 198 +++++++++++++++++
>   support/reexport/reexport.c         | 326 ++++++++++++++++++++++++++++
>   support/reexport/reexport.h         |  18 ++
>   support/reexport/reexport_backend.h |  47 ++++
>   systemd/Makefile.am                 |   5 +-
>   systemd/fsidd.service               |  10 +
>   utils/exportd/Makefile.am           |   4 +-
>   utils/exportfs/Makefile.am          |   3 +
>   utils/exportfs/exportfs.c           |  11 +
>   utils/exportfs/exports.man          |  31 +++
>   utils/mount/Makefile.am             |   3 +-
>   utils/mountd/Makefile.am            |   2 +
>   22 files changed, 1096 insertions(+), 10 deletions(-)
>   create mode 100644 support/reexport/Makefile.am
>   create mode 100644 support/reexport/backend_sqlite.c
>   create mode 100644 support/reexport/fsidd.c
>   create mode 100644 support/reexport/reexport.c
>   create mode 100644 support/reexport/reexport.h
>   create mode 100644 support/reexport/reexport_backend.h
>   create mode 100644 systemd/fsidd.service
> 
Committed... (tag: nfs-utils-2-6-3-rc9)

Thank you!

steved.