f3a121eeeb
Currently the grub_diskfilter_memberlist() function returns all physical
volumes added to a volume group to which a logical volume (LV) belongs.
However, this is suboptimal as it doesn't fit the intended behavior of
returning underlying devices that make up the LV. To give a clear
picture, the result should be identical to running commands below to
display the logical volumes with underlying physical volumes in use.
localhost:~ # lvs -o lv_name,vg_name,devices /dev/system/root
LV VG Devices
root system /dev/vda2(512)
localhost:~ # lvdisplay --maps /dev/system/root
--- Logical volume ---
...
--- Segments ---
Logical extents 0 to 4604:
Type linear
Physical volume /dev/vda2
Physical extents 512 to 5116
As shown above, we can know system-root LV uses only /dev/vda2 to
allocate it's extents, or we can say that /dev/vda2 is the member device
comprising the system-root LV.
It is important to be precise on the member devices, because that helps
to avoid pulling in excessive dependency. Let's use an example to
demonstrate why it is needed.
localhost:~ # findmnt /
TARGET SOURCE FSTYPE OPTIONS
/ /dev/mapper/system-root ext4 rw,relatime
localhost:~ # pvs
PV VG Fmt Attr PSize PFree
/dev/mapper/data system lvm2 a-- 1020.00m 0
/dev/vda2 system lvm2 a-- 19.99g 0
localhost:~ # cryptsetup status /dev/mapper/data
/dev/mapper/data is active and is in use.
type: LUKS1
cipher: aes-xts-plain64
keysize: 512 bits
key location: dm-crypt
device: /dev/vdb
sector size: 512
offset: 4096 sectors
size: 2093056 sectors
mode: read/write
localhost:~ # vgs
VG #PV #LV #SN Attr VSize VFree
system 2 3 0 wz--n- 20.98g 0
localhost:~ # lvs -o lv_name,vg_name,devices
LV VG Devices
data system /dev/mapper/data(0)
root system /dev/vda2(512)
swap system /dev/vda2(0)
We can learn from above that /dev/mapper/data is an encrypted volume and
also gets assigned to volume group "system" as one of it's physical
volumes. And also it is not used by root device, /dev/mapper/system-root,
for allocating extents, so it shouldn't be taking part in the process of
setting up GRUB to access root device.
However, running grub-install reports error as volume group "system"
contains encrypted volume.
error: attempt to install to encrypted disk without cryptodisk
enabled. Set `GRUB_ENABLE_CRYPTODISK=y' in file `/etc/default/grub'.
Certainly we can enable GRUB_ENABLE_CRYPTODISK=y and move on, but that
is not always acceptable since the server may need to be booted unattended.
Additionally, typing passphrase for every system startup can be a big
hassle of which most users would like to avoid.
This patch solves the problem by returning exact physical volume, /dev/vda2,
rightly used by system-root from the example above, thus grub-install will
not error out because the excessive encrypted device to boot the root device
is not configured.
Signed-off-by: Michael Chang <mchang@suse.com>
Tested-by: Olav Reinert <seroton10@gmail.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
This is GRUB 2, the second version of the GRand Unified Bootloader. GRUB 2 is rewritten from scratch to make GNU GRUB cleaner, safer, more robust, more powerful, and more portable. See the file NEWS for a description of recent changes to GRUB 2. See the file INSTALL for instructions on how to build and install the GRUB 2 data and program files. See the file MAINTAINERS for information about the GRUB maintainers, etc. If you found a security vulnerability in the GRUB please check the SECURITY file to get more information how to properly report this kind of bugs to the maintainers. Please visit the official web page of GRUB 2, for more information. The URL is <http://www.gnu.org/software/grub/grub.html>. More extensive documentation is available in the Info manual, accessible using 'info grub' after building and installing GRUB 2. There are a number of important user-visible differences from the first version of GRUB, now known as GRUB Legacy. For a summary, please see: info grub Introduction 'Changes from GRUB Legacy'