Re: [BUG] grub-install fails on devices with high minor numbers

[Andrei Borzenkov <arvidjaar@gmail.com>]

06.11.2015 22:59, Tim Walberg пишет:
> On 11/06/2015 21:26 +0300, Andrei Borzenkov wrote:
>>> 	06.11.2015 19:08, Tim Walberg ??????????:
>>> 	>On some relatively large systems that are used for virtualization,
>>> 	>often containing upwards of 100 virtual machines, we've started running
>>> 	>into issues with GRUB not being able to install on a new virtual machine
>>> 	>(using the typical process of mounting all the VM file systems on the host
>>> 	>and running grub-install under chroot). We've tracked the issue down to this
>>> 	>code, which is clearly erroneous - device minor numbers have been more than
>>> 	>8 bits for quite some time now - in grub-core/osdep/devmapper/getroot.c:
>>> 	>
>>> 	>     char *
>>> 	>     grub_util_devmapper_part_to_disk (struct stat *st,
>>> 	>                                   int *is_part, const char *path)
>>> 	>     {
>>> 	>       int major, minor;
>>> 	>
>>> 	>       if (grub_util_get_dm_node_linear_info (st->st_rdev,
>>> 	>                                          &major, &minor, 0))
>>> 	>         {
>>> 	>           *is_part = 1;
>>> 	>           return grub_find_device ("/dev",
>>> 	>                                    (major << 8) | minor);         <<<<< --------- ERROR!
>>> 	>         }
>>> 	>       *is_part = 0;
>>> 	>       return xstrdup (path);
>>> 	>     }
>>> 	>
>>> 	>When we have enough device-mapper devices (including all their partitions)
>>> 	>on a host that the next newly-added set of devices ends up with minor numbers
>>> 	>outside the 8-bit range, this code fails, with the result that grub-install
>>> 	>can't find the devices that it needs to complete the install.
>>> 	>
>>> 	>There might be other places in the code where similar assumptions are made.
>>> 	>Someone more familiar with the code would probably be better for tracking
>>> 	>those down. But, this one at least needs to be fixed.
>>> 	>
>>> 	
>>> 	
>>> 	Does attached patch help?
>
>>> 	From: Andrei Borzenkov <arvidjaar@gmail.com>
>>> 	Subject: [PATCH] devmapper/getroot: use makedev instead of direct shift
>>> 	
>>> 	Fixes device detection with large number of devices.
>>> 	
>>> 	Reported by Tim Wallberg <twalberg@comcast.net>
>>> 	
>>> 	---
>>> 	 grub-core/osdep/devmapper/getroot.c | 3 +--
>>> 	 1 file changed, 1 insertion(+), 2 deletions(-)
>>> 	
>>> 	diff --git a/grub-core/osdep/devmapper/getroot.c b/grub-core/osdep/devmapper/getroot.c
>>> 	index 0a77a04..64419f6 100644
>>> 	--- a/grub-core/osdep/devmapper/getroot.c
>>> 	+++ b/grub-core/osdep/devmapper/getroot.c
>>> 	@@ -208,8 +208,7 @@ grub_util_devmapper_part_to_disk (struct stat *st,
>>> 	 					 &major, &minor, 0))
>>> 	     {
>>> 	       *is_part = 1;
>>> 	-      return grub_find_device ("/dev",
>>> 	-			       (major << 8) | minor);
>>> 	+      return grub_find_device ("/dev", makedev (major, minor));
>>> 	     }
>>> 	   *is_part = 0;
>>> 	   return xstrdup (path);
>>> 	--
>>> 	tg: (cd6d79c..) u/makedev (depends on: master)
>
> End of included message
>
>
> Yes, that appears to have resolved the issue. I was already testing essentially
> that patch on my own, but wasn't sure if there might be similar assumptions
> made elsewhere in the code.

As far as I can tell, other places used makedev() already. Committed. 
Thanks!