From 5cc00eac24c7019d9696a859f69b587e11f1621e Mon Sep 17 00:00:00 2001 From: Michael Chang Date: Mon, 27 Sep 2021 17:39:56 +0800 Subject: [PATCH] disk/diskfilter: Use nodes in logical volume's segment as member device 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 Tested-by: Olav Reinert Reviewed-by: Daniel Kiper --- grub-core/disk/diskfilter.c | 61 ++++++++++++++++++++++++++----------- 1 file changed, 44 insertions(+), 17 deletions(-) diff --git a/grub-core/disk/diskfilter.c b/grub-core/disk/diskfilter.c index d094f7882..39d74cb86 100644 --- a/grub-core/disk/diskfilter.c +++ b/grub-core/disk/diskfilter.c @@ -396,6 +396,8 @@ grub_diskfilter_memberlist (grub_disk_t disk) grub_disk_dev_t p; struct grub_diskfilter_vg *vg; struct grub_diskfilter_lv *lv2 = NULL; + struct grub_diskfilter_segment *seg; + unsigned int i, j; if (!lv->vg->pvs) return NULL; @@ -427,27 +429,52 @@ grub_diskfilter_memberlist (grub_disk_t disk) } } - for (pv = lv->vg->pvs; pv; pv = pv->next) - { - if (!pv->disk) + for (i = 0, seg = lv->segments; i < lv->segment_count; i++, seg++) + for (j = 0; j < seg->node_count; ++j) + if (seg->nodes[j].pv != NULL) { - /* TRANSLATORS: This message kicks in during the detection of - which modules needs to be included in core image. This happens - in the case of degraded RAID and means that autodetection may - fail to include some of modules. It's an installation time - message, not runtime message. */ - grub_util_warn (_("Couldn't find physical volume `%s'." - " Some modules may be missing from core image."), - pv->name); - continue; + pv = seg->nodes[j].pv; + + if (pv->disk == NULL) + { + /* + * TRANSLATORS: This message kicks in during the detection of + * which modules needs to be included in core image. This happens + * in the case of degraded RAID and means that autodetection may + * fail to include some of modules. It's an installation time + * message, not runtime message. + */ + grub_util_warn (_("Couldn't find physical volume `%s'." + " Some modules may be missing from core image."), + pv->name); + continue; + } + + for (tmp = list; tmp != NULL; tmp = tmp->next) + if (!grub_strcmp (tmp->disk->name, pv->disk->name)) + break; + if (tmp != NULL) + continue; + + tmp = grub_malloc (sizeof (*tmp)); + if (tmp == NULL) + goto fail; + tmp->disk = pv->disk; + tmp->next = list; + list = tmp; } - tmp = grub_malloc (sizeof (*tmp)); - tmp->disk = pv->disk; - tmp->next = list; - list = tmp; - } return list; + + fail: + while (list != NULL) + { + tmp = list; + list = list->next; + grub_free (tmp); + } + + return NULL; } void -- 2.31.1