Merge ~mwhudson/grub/+git/ubuntu:lp-1429327 into ~ubuntu-core-dev/grub/+git/ubuntu:ubuntu

[Michael Hudson-Doyle]

[Steve Langasek (vorlon)]

review: Approve

[Julian Andres Klode (juliank)]

The patch seems to be in the target branch, so marking as merged.

diff --git a/debian/.git-dpm b/debian/.git-dpm
index 685daef..d0221b3 100644
--- a/debian/.git-dpm
+++ b/debian/.git-dpm
@@ -1,6 +1,6 @@
 # see git-dpm(1) from git-dpm package
-82f1d75cd9d0415c3aef23adcc715fc3abc5fd78
-82f1d75cd9d0415c3aef23adcc715fc3abc5fd78
+fe950b01df1486d0f2a1a73a7492e2e40a41de1e
+fe950b01df1486d0f2a1a73a7492e2e40a41de1e
 578bb115fbd47e1c464696f1f8d6183e5443975d
 578bb115fbd47e1c464696f1f8d6183e5443975d
 grub2_2.04.orig.tar.xz
diff --git a/debian/changelog b/debian/changelog
index 88dd6e0..15224fc 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,13 @@
+grub2 (2.04-1ubuntu4) UNRELEASED; urgency=medium
+
+  * d/patches/ubuntu-boot-from-multipath-dependent-symlink.patch: when / is
+    multipathed there will be multiple paths to the partition, so using
+    root=UUID= exposes the boot process to udev races.  In addition 
+    grub-probe --target device / in this case reports /dev/dm-1 or similar --
+    better to use a symlink that depends on the multipath name. (LP: #1429327)
+
+ -- Michael Hudson-Doyle <[e-mail]>  Tue, 06 Aug 2019 12:37:18 +1200
+
 grub2 (2.04-1ubuntu3) eoan; urgency=medium
 
   [ Mathieu Trudel-Lapierre ]
diff --git a/debian/patches/series b/debian/patches/series
index 900d3d4..7b5e184 100644
--- a/debian/patches/series
+++ b/debian/patches/series
@@ -65,3 +65,4 @@ ubuntu-fix-lzma-decompressor-objcopy.patch
 ubuntu-clear-invalid-initrd-spacing.patch
 ubuntu-temp-keep-auto-nvram.patch
 ubuntu-add-devicetree-command-support.patch
+ubuntu-boot-from-multipath-dependent-symlink.patch
diff --git a/debian/patches/ubuntu-boot-from-multipath-dependent-symlink.patch b/debian/patches/ubuntu-boot-from-multipath-dependent-symlink.patch
new file mode 100644
index 0000000..8d67512
--- /dev/null
+++ b/debian/patches/ubuntu-boot-from-multipath-dependent-symlink.patch
@@ -0,0 +1,69 @@
+From fe950b01df1486d0f2a1a73a7492e2e40a41de1e Mon Sep 17 00:00:00 2001
+From: Michael Hudson-Doyle <[e-mail]>
+Date: Tue, 6 Aug 2019 12:31:47 +1200
+Subject: UBUNTU: Boot from multipath-dependent symlink when / is multipathed.
+
+If / is multipathed, there will be multiple paths to the partition, so
+using root=UUID= exposes the boot process to udev races. In addition
+grub-probe --target device / in this case reports /dev/dm-1 or similar
+-- better to use a symlink that depends on the multipath name.
+
+Signed-off-by: Michael Hudson-Doyle <[e-mail]>
+Bug-Ubuntu: https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/1429327
+Patch-Name: ubuntu-boot-from-multipath-dependent-symlink.patch
+---
+ util/grub.d/10_linux.in | 41 +++++++++++++++++++++++++++++++++++++++++
+ 1 file changed, 41 insertions(+)
+
+diff --git a/util/grub.d/10_linux.in b/util/grub.d/10_linux.in
+index d6937cfef..8f3fbc41f 100644
+--- a/util/grub.d/10_linux.in
++++ b/util/grub.d/10_linux.in
+@@ -65,6 +65,47 @@ esac
+ # older kernels.
+ GRUB_DISABLE_LINUX_PARTUUID=${GRUB_DISABLE_LINUX_PARTUUID-true}
+ 
++# get_dm_field_for_dev /dev/dm-0 uuid -> get the device mapper UUID for /dev/dm-0
++# get_dm_field_for_dev /dev/dm-1 name -> get the device mapper name for /dev/dm-1
++# etc
++get_dm_field_for_dev () {
++    dmsetup info -c --noheadings -o $2 $1 2>/dev/null
++}
++
++# Is $1 a multipath device?
++is_multipath () {
++    local dmuuid dmtype
++    dmuuid="$(get_dm_field_for_dev $1 uuid)"
++    if [ $? -ne 0 ]; then
++        # Not a device mapper device -- or dmsetup not installed, and as
++        # multipath depends on kpartx which depends on dmsetup, if there is no
++        # dmsetup then there are not going to be any multipath devices.
++        return 1
++    fi
++    # A device mapper "uuid" is always <type>-<uuid>. If <type> is of the form
++    # part[0-9] then <uuid> is the device the partition is on and we want to
++    # look at that instead. A multipath node always has <type> of mpath.
++    dmtype="${dmuuid%%-*}"
++    if [ "${dmtype#part}" != "$dmtype" ]; then
++        dmuuid="${dmuuid#*-}"
++        dmtype="${dmuuid%%-*}"
++    fi
++    if [ "$dmtype" = "mpath" ]; then
++        return 0
++    else
++        return 1
++    fi
++}
++
++if test -e "${GRUB_DEVICE}" && is_multipath "${GRUB_DEVICE}"; then
++    # If / is multipathed, there will be multiple paths to the partition, so
++    # using root=UUID= exposes the boot process to udev races. In addition
++    # GRUB_DEVICE in this case will be /dev/dm-0 or similar -- better to use a
++    # symlink that depends on the multipath name.
++    GRUB_DEVICE=/dev/mapper/"$(get_dm_field_dev $GRUB_DEVICE name)"
++    GRUB_DISABLE_LINUX_UUID=true
++fi
++
+ # btrfs may reside on multiple devices. We cannot pass them as value of root= parameter
+ # and mounting btrfs requires user space scanning, so force UUID in this case.
+ if ( [ "x${GRUB_DEVICE_UUID}" = "x" ] && [ "x${GRUB_DEVICE_PARTUUID}" = "x" ] ) \