From 811c814677b83874fb631f6c07576765303b615a Mon Sep 17 00:00:00 2001

From: =?UTF-8?q?=C4=90o=C3=A0n=20Tr=E1=BA=A7n=20C=C3=B4ng=20Danh?=

 <congdanhqx@gmail.com>

Date: Sat, 3 Oct 2020 14:23:26 +0700

Subject: [PATCH] rootfs-block: only write root argument for block device

MIME-Version: 1.0

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Some filesystem (e.g. ZFS, and btrfs subvolumes) don't use block

devices. Should they be mounted as `/`, `find_root_block_device`

yields nothing, hence dracut will append this problematic argument

to kernel cmdline:

	root=/dev/block

On a machine that employ root ZFS on LUKS, which was setup with

an OpenPGP-encrypted key file, this argument renders that machine

unbootable. Remove that `root=/dev/block` manually could boot the

machine.

Let check if that device is a block device before write down `root`

argument. This is consistent with the check for block device in

`find_block_device`.

Signed-off-by: Đoàn Trần Công Danh <congdanhqx@gmail.com>

---

 modules.d/95rootfs-block/module-setup.sh | 25 +++++++++++++++----------

 1 file changed, 15 insertions(+), 10 deletions(-)

diff --git a/modules.d/95rootfs-block/module-setup.sh b/modules.d/95rootfs-block/module-setup.sh

index 987373b4..c3982207 100755

--- a/modules.d/95rootfs-block/module-setup.sh

+++ b/modules.d/95rootfs-block/module-setup.sh

@@ -30,7 +30,8 @@ cmdline_journal() {

 }

 cmdline_rootfs() {

-    local _dev=/dev/block/$(find_root_block_device)

+    local _block=$(find_root_block_device)

+    local _dev=/dev/block/$_block

     local _fstype _flags _subvol

     # "--no-hostonly-default-device" can result in empty root_devs

@@ -38,17 +39,21 @@ cmdline_rootfs() {

         return

     fi

-    if [ -e $_dev ]; then

+    if [ -n "$_block" -a -b $_dev ]; then

         printf " root=%s" "$(shorten_persistent_dev "$(get_persistent_dev "$_dev")")"

-        _fstype="$(find_mp_fstype /)"

-        _flags="$(find_mp_fsopts /)"

+    fi

+    _fstype="$(find_mp_fstype /)"

+    _flags="$(find_mp_fsopts /)"

+    if [ -n "$_fstype" ]; then

         printf " rootfstype=%s" "$_fstype"

-        if [[ $use_fstab != yes ]] && [[ $_fstype = btrfs ]]; then

-            _subvol=$(findmnt -e -v -n -o FSROOT --target /) \

-		&& _subvol=${_subvol#/}

-            _flags="$_flags,${_subvol:+subvol=$_subvol}"

-        fi

-        printf " rootflags=%s" "${_flags#,}"

+    fi

+    if [[ $use_fstab != yes ]] && [[ $_fstype = btrfs ]]; then

+        _subvol=$(findmnt -e -v -n -o FSROOT --target /) \

+            && _subvol=${_subvol#/}

+        _flags="$_flags${_subvol:+,subvol=$_subvol}"

+    fi

+    if [ -n "$_flags" ]; then

+        printf " rootflags=%s" "$_flags"

     fi

 }