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From: ludo@gnu.org (Ludovic =?utf-8?Q?Court=C3=A8s?=)
Subject: Re: [PATCH 2/2] system: Add btrfs file system support.
Date: Mon, 05 Dec 2016 21:44:37 +0100
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	(David Craven's message of "Sat, 3 Dec 2016 17:21:13 +0100")
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To: David Craven <david@craven.ch>
Cc: guix-devel <guix-devel@gnu.org>

David Craven <david@craven.ch> skribis:

> The nice thing about having the check procedure be part of the
> <file-system> is that it can be overridden. I'm not sure what use
> cases there are yet. One I can think of is that btrfs device scan is
> only required when using a multi-device configuration like raid. So I
> don't know if we want to run it by default as a %btrfs-checker or do
> nothing by default, and let the user add a custom file system
> pre-mount hook (file-system-checker) when needed.

I don=E2=80=99t know enough about btrfs.  Is it really useful in practice to
have a check procedure that is specific to the instance at hand?

For the other FS types, the check method really belongs in the FS type,
not in the FS instance.  That is, all ext4 file systems are checked in
the same way.  Thus, it doesn=E2=80=99t seem natural to store the fsck meth=
od in
the <file-system> object itself.

There=E2=80=99s also a practical issue with that: users would have to speci=
fy
the fsck method for every single <file-system> object:

  (list (file-system
          ;; =E2=80=A6
          (type "ext4")
          (fsck %ext4-fsck))
       (file-system
          ;; =E2=80=A6
          (type "ext4")
          (fsck %ext4-fsck))   ;again
       (file-system
          ;; =E2=80=A6
          (type "ext4")
          (fsck %ext4-fsck)))  ;and again!  :-)

> A version of Marius'es patch that works would be here:
> http://lists.gnu.org/archive/html/guix-devel/2016-12/msg00087.html

OK, this patch doesn=E2=80=99t have the problem above, but it=E2=80=99s kin=
da cheating.
:-)

I=E2=80=99ll reply separately!

Ludo=E2=80=99.