[PATCH v3] virtiofs support for kexec-tools - kexec - Fedora mailing-lists

23 Sep 2022

This patch add virtiofs support for kexec-tools by introducing a new option
for /etc/kdump.conf:
virtiofs myfs
Where myfs is a variable tag name specified in qemu cmdline
"-device vhost-user-fs-pci,tag=myfs".
The patch covers the following cases:
1) Dumping VM's vmcore to a virtiofs shared directory;
2) When the VM's rootfs is a virtiofs shared directory and dumping the
   VM's vmcore to its subdirectory, such as /var/crash;
3) The combination of case 1 & 2: The VM's rootfs is a virtiofs shared
   directory and dumping the VM's vmcore to another virtiofs shared
   directory.
Case 2 & 3 need dracut >= 057, otherwise VM cannot boot from virtiofs
shared rootfs. But it is not the issue of kexec-tools.
Reviewed-by: Philipp Rudo prudo@redhat.com
Signed-off-by: Tao Liu ltao@redhat.com
---
v1 -> v2:
1) Bump the dracut version to 057
2) Merged get_user_configured_dump_disk() to get_block_dump_target()
   since the latter is the only user.
3) Updated kdump.conf with supported fstype
v2 -> v3:
1) Make _fstype local
2) Drop the dracut version bumping patch. As explained in the
   commit, if dracut < 057, or no virtiofs module added into initramfs,
   the VM won't boot up from virtiofs shared rootfs. So the successful
   booting can ensure virtiofs exist, we don't need to re-ensure it in
   kexec-tools.
---
 dracut-kdump.sh        |  2 +-
 dracut-module-setup.sh |  2 +-
 kdump-lib-initramfs.sh | 24 +++++++++++++++++++++++-
 kdump-lib.sh           | 33 +++++++++++++++------------------
 kdump.conf             |  2 ++
 kdumpctl               |  6 +++---
 mkdumprd               |  2 +-
 7 files changed, 46 insertions(+), 25 deletions(-)

diff --git a/dracut-kdump.sh b/dracut-kdump.sh
index f4456a1..5c980a8 100755
--- a/dracut-kdump.sh
+++ b/dracut-kdump.sh
@@ -519,7 +519,7 @@ read_kdump_confs()
    			DUMP_INSTRUCTION="dump_fs $config_val"
    		fi
    		;;
-		ext[234] | xfs | btrfs | minix | nfs)
+		ext[234] | xfs | btrfs | minix | nfs | virtiofs)
    		config_val=$(get_mntpoint_from_target "$config_val")
    		DUMP_INSTRUCTION="dump_fs $config_val"
    		;;
diff --git a/dracut-module-setup.sh b/dracut-module-setup.sh
index 4c6096a..a790a93 100755
--- a/dracut-module-setup.sh
+++ b/dracut-module-setup.sh
@@ -673,7 +673,7 @@ kdump_install_conf() {
                 _pdev=$(persistent_policy="by-id" kdump_get_persistent_dev "$_val")
                 sed -i -e "s#^${_opt}[[:space:]]+$_val#$_opt $_pdev#" "${initdir}/tmp/$$-kdump.conf"
                 ;;
-            ext[234] | xfs | btrfs | minix)
+            ext[234] | xfs | btrfs | minix | virtiofs)
                 _pdev=$(kdump_get_persistent_dev "$_val")
                 sed -i -e "s#^${_opt}[[:space:]]+$_val#$_opt $_pdev#" "${initdir}/tmp/$$-kdump.conf"
                 ;;
diff --git a/kdump-lib-initramfs.sh b/kdump-lib-initramfs.sh
index 84e6bf7..e982b14 100755
--- a/kdump-lib-initramfs.sh
+++ b/kdump-lib-initramfs.sh
@@ -55,6 +55,11 @@ is_fs_type_nfs()
    [ "$1" = "nfs" ] || [ "$1" = "nfs4" ]
 }
+is_fs_type_virtiofs()
+{
+	[ "$1" = "virtiofs" ]
+}
+
 # If $1 contains dracut_args "--mount", return <filesystem type>
 get_dracut_args_fstype()
 {
@@ -110,6 +115,23 @@ is_raw_dump_target()
    [ -n "$(kdump_get_conf_val raw)" ]
 }
+is_virtiofs_dump_target()
+{
+	if [ -n "$(kdump_get_conf_val virtiofs)" ]; then
+		return 0
+	fi
+
+	if is_fs_type_virtiofs "$(get_dracut_args_fstype "$(kdump_get_conf_val dracut_args)")"; then
+		return 0
+	fi
+
+	if is_fs_type_virtiofs "$(get_fs_type_from_target "$(get_target_from_path "$(get_save_path)")")"; then
+		return 0
+	fi
+
+	return 1
+}
+
 is_nfs_dump_target()
 {
    if [ -n "$(kdump_get_conf_val nfs)" ]; then
@@ -129,5 +151,5 @@ is_nfs_dump_target()
is_fs_dump_target()
 {
-	[ -n "$(kdump_get_conf_val "ext[234]|xfs|btrfs|minix")" ]
+	[ -n "$(kdump_get_conf_val "ext[234]|xfs|btrfs|minix|virtiofs")" ]
 }
diff --git a/kdump-lib.sh b/kdump-lib.sh
index 6d081a8..817652d 100755
--- a/kdump-lib.sh
+++ b/kdump-lib.sh
@@ -81,35 +81,31 @@ to_dev_name()
is_user_configured_dump_target()
 {
-	[[ $(kdump_get_conf_val "ext[234]|xfs|btrfs|minix|raw|nfs|ssh") ]] || is_mount_in_dracut_args
-}
-
-get_user_configured_dump_disk()
-{
-	local _target
-
-	_target=$(kdump_get_conf_val "ext[234]|xfs|btrfs|minix|raw")
-	[[ -n $_target ]] && echo "$_target" && return
-
-	_target=$(get_dracut_args_target "$(kdump_get_conf_val "dracut_args")")
-	[[ -b $_target ]] && echo "$_target"
+	[[ $(kdump_get_conf_val "ext[234]|xfs|btrfs|minix|raw|nfs|ssh|virtiofs") ]] || is_mount_in_dracut_args
 }
get_block_dump_target()
 {
-	local _target _path
+	local _target _fstype
if is_ssh_dump_target || is_nfs_dump_target; then
    	return
    fi
-	_target=$(get_user_configured_dump_disk)
+	_target=$(kdump_get_conf_val "ext[234]|xfs|btrfs|minix|raw|virtiofs")
    [[ -n $_target ]] && to_dev_name "$_target" && return
-	# Get block device name from local save path
-	_path=$(get_save_path)
-	_target=$(get_target_from_path "$_path")
-	[[ -b $_target ]] && to_dev_name "$_target"
+	_target=$(get_dracut_args_target "$(kdump_get_conf_val "dracut_args")")
+	[[ -b $_target ]] && to_dev_name "$_target" && return
+
+	_fstype=$(get_dracut_args_fstype "$(kdump_get_conf_val "dracut_args")")
+	is_fs_type_virtiofs "$_fstype" && echo "$_target" && return
+
+	_target=$(get_target_from_path "$(get_save_path)")
+	[[ -b $_target ]] && to_dev_name "$_target" && return
+
+	_fstype=$(get_fs_type_from_target "$_target")
+	is_fs_type_virtiofs "$_fstype" && echo "$_target" && return
 }
is_dump_to_rootfs()
@@ -125,6 +121,7 @@ get_failure_action_target()
    	# Get rootfs device name
    	_target=$(get_root_fs_device)
    	[[ -b $_target ]] && to_dev_name "$_target" && return
+		is_fs_type_virtiofs "$(get_fs_type_from_target "$_target")" && echo "$_target" && return
    	# Then, must be nfs root
    	echo "nfs"
    fi
diff --git a/kdump.conf b/kdump.conf
index d4fc78b..e598a49 100644
--- a/kdump.conf
+++ b/kdump.conf
@@ -43,6 +43,7 @@
 #             It's recommended to use persistent device names
 #             such as /dev/vg/<devname>.
 #             Otherwise it's suggested to use label or uuid.
+#             Supported fs types: ext[234], xfs, btrfs, minix, virtiofs
 #
 # path <path>
 #           - "path" represents the file system path in which vmcore
@@ -171,6 +172,7 @@
 #ext4 /dev/vg/lv_kdump
 #ext4 LABEL=/boot
 #ext4 UUID=03138356-5e61-4ab3-b58e-27507ac41937
+#virtiofs myfs
 #nfs my.server.com:/export/tmp
 #nfs [2001:db8::1:2:3:4]:/export/tmp
 #ssh user@my.server.com
diff --git a/kdumpctl b/kdumpctl
index 0e37d36..c7efa2c 100755
--- a/kdumpctl
+++ b/kdumpctl
@@ -239,7 +239,7 @@ parse_config()
    		_set_config _fstype "$config_opt" || return 1
    		config_opt=_target
    		;;
-		ext[234] | minix | btrfs | xfs | nfs | ssh)
+		ext[234] | minix | btrfs | xfs | nfs | ssh | virtiofs)
    		_set_config _fstype "$config_opt" || return 1
    		config_opt=_target
    		;;
@@ -478,8 +478,8 @@ check_fs_modified()
    fi
# No need to check in case of raw target.
-	# Currently we do not check also if ssh/nfs target is specified
-	if is_ssh_dump_target || is_nfs_dump_target || is_raw_dump_target; then
+	# Currently we do not check also if ssh/nfs/virtiofs target is specified
+	if is_ssh_dump_target || is_nfs_dump_target || is_raw_dump_target || is_virtiofs_dump_target; then
    	return 0
    fi
diff --git a/mkdumprd b/mkdumprd
index c0f131d..2e5659d 100644
--- a/mkdumprd
+++ b/mkdumprd
@@ -391,7 +391,7 @@ while read -r config_opt config_val; do
    extra_modules)
    	extra_modules="$extra_modules $config_val"
    	;;
-	ext[234] | xfs | btrfs | minix | nfs)
+	ext[234] | xfs | btrfs | minix | nfs | virtiofs)
    	check_user_configured_target "$config_val" "$config_opt"
    	add_mount "$config_val" "$config_opt"
    	;;
-- 
2.33.1

    