[PATCH 4/4] dracut-module-setup: Fix the incorrect dumping target, if the path is bind mounted

[Minfei Huang]

The kdump will dump the core in incorrect target directory, if the
target is bind mounted.

The kdump cann't parse the bind mounted path, if we specifies the vale
"path /var/crash" in the /etc/kdump.conf.

To correct dumping target, we can construct the real dumping path, which
contains two part, one bind mounted path, the other specified dump
target.

Following is an example:
    -bash-4.2# cat /etc/kdump.conf | grep ^path
    path /var/crash

    -bash-4.2# findmnt /var | tail -n 1 | awk '{print $2}'
    /dev/mapper/atomicos-root[/ostree/deploy/rhel-atomic-host/var]

    -bash-4.2# findmnt -v /var | tail -n 1 | awk '{print $2}'
    /dev/mapper/atomicos-root

Then we can found it that the real path of dumping core is
/ostree/deploy/rhel-atomic-host/var/crash.

Signed-off-by: Minfei Huang <mhuang(a)redhat.com&gt;
---
 dracut-module-setup.sh | 46 +++++++++++++++++++++++++++++++++++++++++++---
 mkdumprd               | 22 +++++++++++++++++++++-
 2 files changed, 64 insertions(+), 4 deletions(-)

diff --git a/dracut-module-setup.sh b/dracut-module-setup.sh
index 477ede1..6a8c631 100755
--- a/dracut-module-setup.sh
+++ b/dracut-module-setup.sh
@@ -312,7 +312,7 @@ default_dump_target_install_conf()
 {
     local _target _fstype
     local _mntpoint
-    local _save_path
+    local _save_path _update_path=0
 
     is_user_configured_dump_target && return
 
@@ -321,6 +321,18 @@ default_dump_target_install_conf()
 
     _mntpoint=$(get_mntpoint_from_path $_save_path)
     _target=$(get_target_from_path $_save_path)
+
+    if is_bind_mount $_mntpoint; then
+        _save_path=$(cut_out_substring $_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
+
+        local _absolute_save_path=$(get_mntpoint_from_target $_target)/$_save_path
+
+        _mntpoint=$(get_mntpoint_from_path $_absolute_save_path)
+        _update_path=1
+    fi
+
     if [ "$_mntpoint" != "/" ]; then
         _fstype=$(get_fs_type_from_target $_target)
 
@@ -333,13 +345,36 @@ default_dump_target_install_conf()
 
         echo "$_fstype $_target" >> ${initdir}/tmp/$$-kdump.conf
 
-        _save_path=$(cut_out_substring $_save_path $_mntpoint)
+        if [[ $_update_path = 0 ]]; then
+            _save_path=$(cut_out_substring $_save_path $_mntpoint)
+            _update_path=1
+        fi
+    fi
 
+    if [[ $_update_path = 1 ]]; then
         #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
     fi
+}
 
+adjust_bind_mount_path()
+{
+    local _target=$1
+    local _save_path=$(get_option_value "path")
+    [ -z "$_save_path" ] && _save_path=$DEFAULT_PATH
+    local _absolute_save_path=$(get_mntpoint_from_target $config_val)/$_save_path
+    local _mntpoint=$(get_mntpoint_from_path $_absolute_save_path)
+
+    if is_bind_mount $_mntpoint; then
+        local _path=$(cut_out_substring $_absolute_save_path $_mntpoint)
+        # the real dump path in the 2nd kernel, if the mount point is bind mounted.
+        _path=$(get_bind_mount_directory $_mntpoint)/$_path
+
+        #erase the old path line, then insert the parsed path
+        sed -i "/^path/d" ${initdir}/tmp/$$-kdump.conf
+        echo "path $_path" >> ${initdir}/tmp/$$-kdump.conf
+    fi
 }
 
 #install kdump.conf and what user specifies in kdump.conf
@@ -353,9 +388,14 @@ 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
+            adjust_bind_mount_path "$config_val"
+            ;;
+        ssh)
+            kdump_install_net "$config_val"
             ;;
-        ssh|nfs)
+        nfs)
             kdump_install_net "$config_val"
+            adjust_bind_mount_path "$config_val"
             ;;
         kdump_pre|kdump_post|extra_bins)
             dracut_install $config_val
diff --git a/mkdumprd b/mkdumprd
index 7fdcebf..a3378fd 100644
--- a/mkdumprd
+++ b/mkdumprd
@@ -359,6 +359,16 @@ handle_default_dump_target()
 
     _mntpoint=$(get_mntpoint_from_path $SAVE_PATH)
     _target=$(get_target_from_path $SAVE_PATH)
+
+    if is_bind_mount $_mntpoint; then
+        SAVE_PATH=$(cut_out_substring $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
+
+        local _absolute_save_path=$(get_mntpoint_from_target $_target)/$SAVE_PATH
+        _mntpoint=$(get_mntpoint_from_path $_absolute_save_path)
+    fi
+
     if [ "$_mntpoint" != "/" ]; then
         SAVE_PATH=$(cut_out_substring $SAVE_PATH $_mntpoint)
         _fstype=$(get_fs_type_from_target $_target)
@@ -530,8 +540,18 @@ do
         if [ "$config_opt" = "nfs" ]; then
             add_dracut_module "nfs"
         fi
+
+        _absolute_save_path=$(make_absolute_save_path $config_val)
+        _mntpoint=$(get_mntpoint_from_path $_absolute_save_path)
+        if is_bind_mount $_mntpoint; then
+            _bind_dir=$(get_bind_mount_directory $_mntpoint)
+            SAVE_PATH=$(cut_out_substring $SAVE_PATH $_bind_dir)
+            # the real dump path in the 2nd kernel, if the mount point is bind mounted.
+            SAVE_PATH=$_bind_dir/$SAVE_PATH
+        fi
+
         add_mount "$config_val"
-        check_save_path_fs $(make_absolute_save_path $config_val)
+        check_save_path_fs $_absolute_save_path
         check_size fs $config_val
         ;;
     raw)
-- 
1.9.3