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Fix root device detection for lvm2

PATCH In review sean finney 3 participants 5 messages Jun 2, 2010 – Jul 2, 2010

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sean finney

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#0 lore raw

PATCH 1/1 Fix root device detection for lvm2

If you have a single / filesystem on lvm2, the boot process will hang waiting for a root filesystem that never appears. This patch modifies the logic in deciding what the root device actually is, and allows the initramfs to succesfully load the root filesystem.

The attached patch has been in use in the debian "grub2" packages for quite a while, so I assume it's safe to use :)

util/grub.d/10_linux.in +2 -1
Index: b/util/grub.d/10_linux.in
===================================================================
@@ -43,7 +43,8 @@
 esac
 
 if [ "x${GRUB_DEVICE_UUID}" = "x" ] || [ "x${GRUB_DISABLE_LINUX_UUID}" = "xtrue" ] \
-    || ! test -e "/dev/disk/by-uuid/${GRUB_DEVICE_UUID}" ; then
+    || ! test -e "/dev/disk/by-uuid/${GRUB_DEVICE_UUID}" \
+    || [ "`grub-probe -t abstraction --device ${GRUB_DEVICE} | sed -e 's,.*\(lvm\).*,\1,'`" = "lvm"  ] ; then
   LINUX_ROOT_DEVICE=${GRUB_DEVICE}
 else
   LINUX_ROOT_DEVICE=UUID=${GRUB_DEVICE_UUID}
#1 lore raw
Quoted 6 lines · sean finney

Index: b/util/grub.d/10_linux.in
===================================================================

util/grub.d/10_linux.in line 50

Quoted 9 lines
util/grub.d/10_linux.in +2 -1
@@ -43,7 +43,8 @@
 esac
 
 if [ "x${GRUB_DEVICE_UUID}" = "x" ] || [ "x${GRUB_DISABLE_LINUX_UUID}" = "xtrue" ] \
-    || ! test -e "/dev/disk/by-uuid/${GRUB_DEVICE_UUID}" ; then
+    || ! test -e "/dev/disk/by-uuid/${GRUB_DEVICE_UUID}" \
+    || [ "`grub-probe -t abstraction --device ${GRUB_DEVICE} | sed -e 's,.*\(lvm\).*,\1,'`" = "lvm"  ] ; then
   LINUX_ROOT_DEVICE=${GRUB_DEVICE}
 else
   LINUX_ROOT_DEVICE=UUID=${GRUB_DEVICE_UUID}

Applied with some chages. Thanks

Signature · 2 lines
Regards
Vladimir 'φ-coder/phcoder' Serbinenko
#2 lore raw
Quoted 8 lines · Vladimir 'φ-coder/phcoder' Serbinenko
Quoted 7 lines · sean finney

Index: b/util/grub.d/10_linux.in
===================================================================

util/grub.d/10_linux.in +0 -0
@@ -43,7 +43,8 @@
 esac
Quoted 9 lines

util/grub.d/10_linux.in line 50

Quoted 7 lines
util/grub.d/10_linux.in +2 -1
 if [ "x${GRUB_DEVICE_UUID}" = "x" ] || [ "x${GRUB_DISABLE_LINUX_UUID}" = "xtrue" ] \
-    || ! test -e "/dev/disk/by-uuid/${GRUB_DEVICE_UUID}" ; then
+    || ! test -e "/dev/disk/by-uuid/${GRUB_DEVICE_UUID}" \
+    || [ "`grub-probe -t abstraction --device ${GRUB_DEVICE} | sed -e 's,.*\(lvm\).*,\1,'`" = "lvm"  ] ; then
   LINUX_ROOT_DEVICE=${GRUB_DEVICE}
 else
   LINUX_ROOT_DEVICE=UUID=${GRUB_DEVICE_UUID}

Applied with some chages. Thanks

The changes seem to have been to simplify the test to:

  [ "x`grub-probe -t abstraction --device ${GRUB_DEVICE}`" = "xlvm"  ]

Unfortunately this is an incorrect simplification. grub-probe can print multiple abstractions, and does in the case of e.g. LVM on RAID. If it is correct to avoid UUIDs for plain LVM, it is also correct to avoid them for LVM on RAID.

Signature · 1 line
Colin Watson                                       [[email protected]]
#3 lore raw
Quoted 21 lines · Colin Watson
Quoted 9 lines · Vladimir 'φ-coder/phcoder' Serbinenko
Quoted 7 lines · sean finney

Index: b/util/grub.d/10_linux.in
===================================================================

util/grub.d/10_linux.in +0 -0
@@ -43,7 +43,8 @@
 esac
Quoted 10 lines

util/grub.d/10_linux.in line 50

Quoted 8 lines
util/grub.d/10_linux.in +2 -1
 if [ "x${GRUB_DEVICE_UUID}" = "x" ] || [ "x${GRUB_DISABLE_LINUX_UUID}" = "xtrue" ] \
-    || ! test -e "/dev/disk/by-uuid/${GRUB_DEVICE_UUID}" ; then
+    || ! test -e "/dev/disk/by-uuid/${GRUB_DEVICE_UUID}" \
+    || [ "`grub-probe -t abstraction --device ${GRUB_DEVICE} | sed -e 's,.*\(lvm\).*,\1,'`" = "lvm"  ] ; then
   LINUX_ROOT_DEVICE=${GRUB_DEVICE}
 else
   LINUX_ROOT_DEVICE=UUID=${GRUB_DEVICE_UUID}

Applied with some chages. Thanks

Quoted 10 lines

The changes seem to have been to simplify the test to:

  [ "x`grub-probe -t abstraction --device ${GRUB_DEVICE}`" = "xlvm"  ]

Unfortunately this is an incorrect simplification. grub-probe can print multiple abstractions, and does in the case of e.g. LVM on RAID. If it is correct to avoid UUIDs for plain LVM, it is also correct to avoid them for LVM on RAID.

Ok I agree. The problem with original patch was that it would accept ttttlvmuuu too. Feel free to fix.

Signature · 2 lines
Regards
Vladimir 'φ-coder/phcoder' Serbinenko
#4 lore raw
Quoted 5 lines · Vladimir 'φ-coder/phcoder' Serbinenko
Quoted 4 lines · Colin Watson

The changes seem to have been to simplify the test to:

  [ "x`grub-probe -t abstraction --device ${GRUB_DEVICE}`" = "xlvm"  ]
Quoted 7 lines
Quoted 4 lines

Unfortunately this is an incorrect simplification. grub-probe can print multiple abstractions, and does in the case of e.g. LVM on RAID. If it is correct to avoid UUIDs for plain LVM, it is also correct to avoid them for LVM on RAID.

Ok I agree. The problem with original patch was that it would accept ttttlvmuuu too. Feel free to fix.

Fair enough. Done (r2503).

Signature · 1 line
Colin Watson                                       [[email protected]]