[bug #50702] grub2-mkconfig very slow

[Pascal COMBES]

URL:
  <http://savannah.gnu.org/bugs/?50702>

                 Summary: grub2-mkconfig very slow
                 Project: GNU GRUB
            Submitted by: pascom
            Submitted on: Sun 02 Apr 2017 08:25:42 AM UTC
                Category: Configuration
                Severity: Major
                Priority: 5 - Normal
              Item Group: None
                  Status: None
                 Privacy: Public
             Assigned to: None
         Originator Name: Pascal COMBES
        Originator Email: address@hidden
             Open/Closed: Open
         Discussion Lock: Any
                 Release: 
                 Release: 2.02~beta1
         Reproducibility: Every Time
         Planned Release: None

    _______________________________________________________

Details:

I noticed that upgrading the kernel is very long on my PC (>2min on Intel Core
i7-4800MQ). I investigated and found that grub2-mkconfig took so much time.
Deepening the analysis showed that it was in fact Linux system detection
(90linux-distro) by os-prober bash scripts on an unmounted LVM partition with
an ext4 (detected as ext2 by grub2-mount) filesystem (with lib folder in the
root but I guess the same problem occurs when the partition contains a real
undetected linux-distro).
I finally found out that the problem comes from ls taking very long on the lib
folder of the grub2 mounted filesystem. I do not know if it is a FUSE problem
or a grub2 problem.
My version of gurb2 is 2.02-beta2 (OpensSUSE Leap 42.2)
I think that you will reproduce the problem by:
    -Formatting in ext4 an LVM logical volume.
    -Putting there a /lib folder with a lot of files and folders (mine has 264
files and folders)
    -Unmounting it
    -Running os-prober (or grub2-mkconfig with os-probing enabled)

To solve temporarily the problem on my system, I added the (reasonable?)
condition that a linux root filesystem must contain a /usr and a /var folder
(see atttached file), which bypasses the ls check. This will not be sufficient
on a system with a real unknown linux distro.

If you need some help do not hesitate to contact me.



    _______________________________________________________

File Attachments:


-------------------------------------------------------
Date: Sun 02 Apr 2017 08:25:42 AM UTC  Name: 90linux-distro  Size: 5kB   By:
pascom

<http://savannah.gnu.org/bugs/download.php?file_id=40231>

    _______________________________________________________

Reply to this item at:

  <http://savannah.gnu.org/bugs/?50702>

_______________________________________________
  Message sent via/by Savannah
  http://savannah.gnu.org/