[PATCH 5/5 v4] dracut-module-setup: Enhance kdump to support the bind mounted feature in Atomic

[Minfei Huang]

Kdump will dump the vmcore in incorrect target directory, if the target
is bind mounted.

As commented in the previous patch, we can construct the real path in
Atomic, which contains two part, one bind mounted path, the other
specified dump path. Then replace the path as the real path in
/etc/kdump.conf.

findmnt can find the real path for nfs, although the path is in bind
mode. So nfs can work well with the path in bind mode.

Signed-off-by: Minfei Huang <mhuang(a)redhat.com&gt;
Acked-by: Dave Young <dyoung(a)redhat.com&gt;
---
 dracut-module-setup.sh | 43 +++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 41 insertions(+), 2 deletions(-)

diff --git a/dracut-module-setup.sh b/dracut-module-setup.sh
index 540e154..73ab938 100755
--- a/dracut-module-setup.sh
+++ b/dracut-module-setup.sh
@@ -311,8 +311,7 @@ kdump_install_net() {
 default_dump_target_install_conf()
 {
     local _target _fstype
-    local _mntpoint
-    local _save_path
+    local _mntpoint _save_path
 
     is_user_configured_dump_target && return
 
@@ -324,6 +323,17 @@ default_dump_target_install_conf()
 
     _mntpoint=$(get_mntpoint_from_path $_save_path)
     _target=$(get_target_from_path $_save_path)
+
+    if is_atomic && is_bind_mount $_mntpoint; then
+        _save_path=${_save_path##"$_mntpoint"}
+        # the real dump path in the 2nd kernel, if the mount point is bind mounted.
+        _save_path=$(get_bind_mount_directory $_mntpoint)/$_save_path
+        _mntpoint=$(get_mntpoint_from_target $_target)
+
+        # the absolute path in the 1st kernel
+        _save_path=$_mntpoint/$_save_path
+    fi
+
     if [ "$_mntpoint" != "/" ]; then
         _fstype=$(get_fs_type_from_target $_target)
 
@@ -336,7 +346,33 @@ default_dump_target_install_conf()
 
         echo "$_fstype $_target" >> ${initdir}/tmp/$$-kdump.conf
 
+        # strip the duplicated "/"
+        _save_path=$(echo $_save_path | tr -s /)
         _save_path=${_save_path##"$_mntpoint"}
+    fi
+
+    #erase the old path line, then insert the parsed path
+    sed -i "/^path/d" ${initdir}/tmp/$$-kdump.conf
+    echo "path $_save_path" >> ${initdir}/tmp/$$-kdump.conf
+}
+
+adjust_bind_mount_path()
+{
+    local _target=$1
+    local _save_path=$(get_option_value "path")
+    [ -z "$_save_path" ] && _save_path=$DEFAULT_PATH
+
+    # strip the duplicated "/"
+    _save_path=$(echo $_save_path | tr -s /)
+
+    local _absolute_save_path=$(get_mntpoint_from_target $_target)/$_save_path
+    _absolute_save_path=$(echo "$_absolute_save_path" | tr -s /)
+    local _mntpoint=$(get_mntpoint_from_path $_absolute_save_path)
+
+    if is_bind_mount $_mntpoint; then
+        _save_path=${_absolute_save_path##"$_mntpoint"}
+        # the real dump path in the 2nd kernel, if the mount point is bind mounted.
+        _save_path=$(get_bind_mount_directory $_mntpoint)/$_save_path
 
         #erase the old path line, then insert the parsed path
         sed -i "/^path/d" ${initdir}/tmp/$$-kdump.conf
@@ -355,6 +391,9 @@ kdump_install_conf() {
         case "$config_opt" in
         ext[234]|xfs|btrfs|minix|raw)
             sed -i -e "s#^$config_opt[[:space:]]\+$config_val#$config_opt
$(kdump_to_udev_name $config_val)#" ${initdir}/tmp/$$-kdump.conf
+            if is_atomic; then
+                adjust_bind_mount_path "$config_val"
+            fi
             ;;
         ssh|nfs)
             kdump_install_net "$config_val"
-- 
1.9.3