use findmnt instead of blkid in mkdumprd

Previously to_dev_name use blkid to get dev name from dump target,
but blkid can not handle UUID/LABEL with quotes so to_dev_name will
silently fail.

Because we enforce dump target being mounted before creating kdump
initrd, so change to use findmnt is fine. findmnt can handle input
params with quotes.

to_dev_name is not necessary anymore, just remove it.
Also there's another user of it is for checking if the dev is root
or not, here change to use findmnt for this as well.

Tested the rootfs dump, UUID with/without quotes dump.

Signed-off-by: Dave Young <dyoung@redhat.com>
Reviewed-by: Caspar Zhang <czhang@redhat.com>
Acked-by: Baoquan He <bhe@redhat.com>

mkdumprd

@@ -59,35 +59,23 @@ add_dracut_sshkey() {
 # Generic substring function.  If $2 is in $1, return 0.
 strstr() { [[ $1 =~ $2 ]]; }
 
-to_dev_name() {
-    local dev="$1"
-
-    case "$dev" in
-    UUID=*)
-        dev=`blkid -U "${dev#UUID=}"`
-        ;;
-    LABEL=*)
-        dev=`blkid -L "${dev#LABEL=}"`
-        ;;
-    esac
-    echo $dev
-}
-
-get_rootdev() {
-    mount | grep 'on / ' | grep -v rootfs | awk '{print $1}'
+target_is_root() {
+    local _t
+    _t=$(findmnt -k -n -r -o TARGET $1|sort|head -1)
+    [ "$_t" = "/" ]
 }
 
 to_mount() {
-    local _dev _t _o _mntopts _pdev
-    _dev=$(to_dev_name $1)
+    local _dev=$1 _s _t _o _mntopts _pdev
+    _s=$(findmnt -k -f -n -r -o SOURCE $_dev)
     _t=$(findmnt -k -f -n -r -o TARGET,FSTYPE $_dev)
     _o=$(findmnt -k -f -n -r -o OPTIONS $_dev)
     [ -z "$_t" -o -z "$_o" ] && return
     _o=${_o/#ro/rw} #mount fs target as rw in 2nd kernel
     _mntopts="$_t $_o"
     #for non-nfs _dev converting to use udev persistent name
-    if [ -b "$_dev" ]; then
-        _pdev="$(get_persistent_dev $_dev)"
+    if [ -b "$_s" ]; then
+        _pdev="$(get_persistent_dev $_s)"
     else
         _pdev=$_dev
     fi
@@ -222,9 +210,9 @@ verify_core_collector() {
 }
 
 add_mount() {
-    local _dev=$(to_dev_name "$1")
     local _mnt=$(to_mount "$1")
-    if [ "$_dev" = "$(get_rootdev)" ]; then
+
+    if target_is_root "$1"; then
         :
     elif [ -n "$_mnt" ]; then
         add_dracut_mount "$_mnt"