Libguestfs - May 2022 - [PATCH v2v 2/2] convert: Remove /dev/mapper/osprober-* devices left around by grub2

These devices can be left around by grub2 when it runs the osprober
tool after we run ?/sbin/grub2-mkconfig -o /boot/grub2/grub.cfg?.
They are read-only mirrors of existing filesystems.  These confuse
later steps in conversion, specifically fstrim.

Reported-by: Ming Xie
Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=2003503
---
 convert/linux_bootloaders.ml | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/convert/linux_bootloaders.ml b/convert/linux_bootloaders.ml
index a70b65a41c..7c5fb0be3f 100644
--- a/convert/linux_bootloaders.ml
+++ b/convert/linux_bootloaders.ml
@@ -345,7 +345,14 @@ object (self)
   method remove_console = self#grub2_update_console ~remove:true
 
   method update () -    ignore (g#command [| grub2_mkconfig_cmd;
"-o"; grub_config |])
+    ignore (g#command [| grub2_mkconfig_cmd; "-o"; grub_config |]);
+
+    (* Grub2 runs osprober which sometimes leaves around read-only
+     * device-mapper maps covering existing filesystems.  These
+     * confuse later steps (especially fstrim).  So just delete
+     * any if found. (RHBZ#2003503).
+     *)
+    ignore (g#command [| "bash"; "-c"; "rm -f
/dev/mapper/osprober-*" |])
 
   method get_config_file ()      grub_config
-- 
2.35.1

On 05/17/22 12:59, Richard W.M. Jones wrote:
> These devices can be left around by grub2 when it runs the osprober
> tool after we run ?/sbin/grub2-mkconfig -o /boot/grub2/grub.cfg?.
> They are read-only mirrors of existing filesystems.  These confuse
> later steps in conversion, specifically fstrim.
> 
> Reported-by: Ming Xie
> Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=2003503
> ---
>  convert/linux_bootloaders.ml | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/convert/linux_bootloaders.ml b/convert/linux_bootloaders.ml
> index a70b65a41c..7c5fb0be3f 100644
> --- a/convert/linux_bootloaders.ml
> +++ b/convert/linux_bootloaders.ml
> @@ -345,7 +345,14 @@ object (self)
>    method remove_console = self#grub2_update_console ~remove:true
>  
>    method update () > -    ignore (g#command [| grub2_mkconfig_cmd;
"-o"; grub_config |])
> +    ignore (g#command [| grub2_mkconfig_cmd; "-o"; grub_config
|]);
> +
> +    (* Grub2 runs osprober which sometimes leaves around read-only
> +     * device-mapper maps covering existing filesystems.  These
> +     * confuse later steps (especially fstrim).  So just delete
> +     * any if found. (RHBZ#2003503).
> +     *)
> +    ignore (g#command [| "bash"; "-c"; "rm -f
/dev/mapper/osprober-*" |])
>  
>    method get_config_file () >      grub_config
> 
Hmm... I'm not sure why this is better than "dmsetup remove", but
it
does not really matter. We need these nodes to disappear only for the
remainder of the conversion -- so command that effects that suffices!

Reviewed-by: Laszlo Ersek <lersek at redhat.com>

Thanks!
Laszlo