[PATCH 1/2] pass mount info to dracut when default target is a separate disk

[Baoquan He]

When user does not specify dump target explicitly, it's better to
dump to the "path" specified. That means after dump user enter into
1st kernel, can find vmcore in the "path". If that path is in root
fs, vmcore is stored in root fs. If separate disk is mounted on
any tier of "path", we just dump vmcore into the left path on the
left separate disk.

E.g in kdump.conf
path /mnt/nfs

in mount info,
/dev/vdb on /mnt type ext4 (rw,relatime,seclabel,data=ordered)

Then vmcore will be saved in /nfs of /dev/vdb.

In this patch, pass mount info to dracut in this case if separate
disk is mounted on any tier of "path".

Signed-off-by: Baoquan He <bhe at redhat.com>
---
 mkdumprd | 23 ++++++++++++++---------
 1 file changed, 14 insertions(+), 9 deletions(-)

diff --git a/mkdumprd b/mkdumprd
index 241a426..d792b42 100644
--- a/mkdumprd
+++ b/mkdumprd
@@ -355,12 +355,12 @@ get_block_dump_target()
     [ -b "$_target" ] && echo $(to_dev_name $_target)
 }
 
-# If no dump disk is specified make sure /var/crash is not mounted on a
-# separate disk.
-check_block_dump_target()
+#handle the case user does not specify the dump target explicitly
+handle_default_dump_target()
 {
     local _target
     local _mntpoint
+    local _ret
 
     _target=$(get_user_configured_dump_disk)
     [ -n "$_target" ] && return
@@ -368,11 +368,16 @@ check_block_dump_target()
     _target=$(get_root_fs_device)
     if [ -b "$_target" ]; then
         mkdir -p $SAVE_PATH
-        _mntpoint=`df $SAVE_PATH | tail -1 |  awk '{print $NF}'`
+        _ret=$?
+        if [ $_ret -ne 0 ]; then
+            perror_exit "mkdir failed on $SAVE_PATH"
+        fi
+        _mntpoint=$(df $SAVE_PATH | tail -1 |  awk '{print $NF}')
         if [ "$_mntpoint" != "/" ]; then
-            perror "No dump target specified. Default dump target is rootfs block device."
-            perror "But dump path $SAVE_PATH is not backed by rootfs block device. "
-            perror_exit "Either explicitly specify a dump target or specify a dump path backed by rootfs block device"
+            SAVE_PATH=$(echo $SAVE_PATH | sed "s,$_mntpoint,,")
+            _target=$(findmnt -k -f -n -o SOURCE $_mntpoint)
+            add_mount "$_target"
+            check_size fs $_target
         fi
     fi
 }
@@ -500,8 +505,6 @@ check_crypt()
     return 1
 }
 
-check_block_dump_target
-
 if ! check_resettable; then
     exit 1
 fi
@@ -521,6 +524,8 @@ if [ "$(uname -m)" = "s390x" ]; then
     add_dracut_module "znet"
 fi
 
+handle_default_dump_target
+
 while read config_opt config_val;
 do
     # remove inline comments after the end of a directive.
-- 
1.8.5.3