Re: [PATCH 4/6] fstests: btrfs: add helper function to check if btrfs is module

[Eryu Guan <eguan@redhat.com>]

On Tue, May 17, 2016 at 10:32:08PM +0800, Anand Jain wrote:
> We need btrfs to be a module so that it can unloaded and reloaded,
> so that we can clean up the btrfs internal in memory device list.

It looks like a bug to me if btrfs needs to reload module to clean up
the device list. If a user builds btrfs in kernel then he cannot replace
btrfs device properly? Or it's not totally clear to me why a test needs
to reload btrfs module.

> 
> This patch adds _require_btrfs_unloadable() and _reload_btrfs_ko()
> to help with the same.
> 
> Signed-off-by: Anand Jain <anand.jain@oracle.com>
> ---
>  common/rc | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/common/rc b/common/rc
> index f2b39ddbee0c..a9391b4cbf57 100644
> --- a/common/rc
> +++ b/common/rc
> @@ -1403,6 +1403,18 @@ _supported_os()
>      _notrun "not suitable for this OS: $HOSTOS"
>  }
>  
> +_require_btrfs_unloadable()

The name seems misleading, the name indicates that it requires btrfs to
be unloadable, but in the code it _notrun if btrfs is unloadable.

Thanks,
Eryu

> +{
> +	modprobe -r btrfs || _notrun "btrfs unloadable"
> +	modprobe btrfs || _notrun "Can't load btrfs"
> +}
> +
> +_reload_btrfs_ko()
> +{
> +	modprobe -r btrfs || _fail "btrfs unload failed"
> +	modprobe btrfs || _fail "btrfs load failed"
> +}
> +
>  # this test needs a scratch partition - check we're ok & unmount it
>  # No post-test check of the device is required. e.g. the test intentionally
>  # finishes the test with the filesystem in a corrupt state
> -- 
> 2.7.0
> 
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