Re: [Libguestfs] [PATCH v2v] convert: Ignore /dev/mapper/osprober-* devices when trimming
On 05/16/22 17:46, Richard W.M. Jones wrote:
These devices can be left around by either grub2 or the osprober
tool.
They are read-only mirrors of existing filesystems and it appears we
can safely ignore them.
Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=2003503
---
convert/convert.ml | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/convert/convert.ml b/convert/convert.ml
index 87fca7252b..997f6b08bd 100644
--- a/convert/convert.ml
+++ b/convert/convert.ml
@@ -194,10 +194,16 @@ and do_fstrim g inspect =
(* Get all filesystems. *)
let fses = g#list_filesystems () in
+ (* Ignore unknown/swap devices. *)
let fses = List.filter_map (
function (_, ("unknown"|"swap")) -> None | (dev, _) ->
Some dev
) fses in
+ (* Ignore filesystems left around by osprober (RHBZ#2003503). *)
+ let fses =
+ List.filter (fun dev -> not (String.is_prefix dev
"/dev/mapper/osprober-"))
+ fses in
+
(* Trim the filesystems. *)
List.iter (
fun dev ->
I've read up on os-prober:
https://www.thegeekdiary.com/how-to-disable-os-prober-in-centos-rhel-7/
https://github.com/campadrenalin/os-prober
http://joeyh.name/code/os-prober/
and it's *absolutely infuriating* that os-prober itself, or whatever
invokes os-prober, litters the system with block device nodes. In fact,
I don't even know how it is *possible* for a device node to be left
around under /dev/mapper -- I thought /dev/mapper/ would be re-populated
*from zero* every time the system boots? Do we have something in the
appliance perhaps that *creates* these files?
I'm quite unhappy about ignoring these filesystems in "do_fstrim"
*only*. If guestfs_list_filesystems() returns them in the first place,
won't that cause confusion for other libguestfs applications or scripts?
Do we expect the same filesystem to appear multiply in the
list-filesystems output?
I think this is a serious bug in some component different from
libguestfs / virt-v2v.
Hmmm... After reading your comment
<https://bugzilla.redhat.com/show_bug.cgi?id=2003503#c12>;, I think we
absolutely need to report a bug for grub2. I'll contact the rhboot team.
I don't disagree that we have to work it around, but until we understand
the problem better, I don't feel safe about filtering these nodes out
only in virt-v2v's trimming function.
Thanks
Laszlo