Save the final failure information to log file if saving vmcore failed

Currently, if saving vmcore failed, the final failure information won't
be saved to the kexec-dmesg.log, because the action of saving the log
occurs before the final log is printed, it has no chance to save the
log(marked it with the '^^^' below) to the log file(kexec-dmesg.log).
For example:

[1] console log:
[    3.589967] kdump[453]: saving vmcore-dmesg.txt to /sysroot//var/crash/127.0.0.1-2020-11-26-14:19:17/
[    3.627261] kdump[458]: saving vmcore-dmesg.txt complete
[    3.633923] kdump[460]: saving vmcore
[    3.661020] kdump[465]: saving vmcore failed
                           ^^^^^^^^^^^^^^^^^^^^
[2] kexec-dmesg.log:
Nov 26 14:19:17 kvm-06-guest25.hv2.lab.eng.bos.redhat.com kdump[453]: saving vmcore-dmesg.txt to /sysroot//var/crash/127.0.0.1-2020-11-26-14:19:17/
Nov 26 14:19:17 kvm-06-guest25.hv2.lab.eng.bos.redhat.com kdump[458]: saving vmcore-dmesg.txt complete
Nov 26 14:19:17 kvm-06-guest25.hv2.lab.eng.bos.redhat.com kdump[460]: saving vmcore

Let's improve it in order to avoid the loss of important information.

Signed-off-by: Lianbo Jiang <lijiang@redhat.com>
Acked-by: Kairui Song <kasong@redhat.com>

dracut-kdump.sh

@@ -105,10 +105,12 @@ dump_raw()
 
 dump_ssh()
 {
-    local ret
+    local _ret=0
+    local _exitcode=0 _exitcode2=0
     local _opt="-i $1 -o BatchMode=yes -o StrictHostKeyChecking=yes"
     local _dir="$KDUMP_PATH/$HOST_IP-$DATEDIR"
     local _host=$2
+    local _vmcore="vmcore"
 
     dinfo "saving to $_host:$_dir"
 
@@ -122,25 +124,36 @@ dump_ssh()
 
     if [ "${CORE_COLLECTOR%%[[:blank:]]*}" = "scp" ]; then
         scp -q $_opt /proc/vmcore "$_host:$_dir/vmcore-incomplete"
-        ret=$?
+        _exitcode=$?
-        save_log
-        scp -q $_opt $KDUMP_LOG_FILE "$_host:$_dir/"
-        if [ $ret -ne 0 ]; then
-            return 1
-        fi
-        ssh $_opt $_host "mv $_dir/vmcore-incomplete $_dir/vmcore" || return 1
     else
         $CORE_COLLECTOR /proc/vmcore | ssh $_opt $_host "dd bs=512 of=$_dir/vmcore-incomplete"
-        ret=$?
+        _exitcode=$?
-        save_log
+        _vmcore="vmcore.flat"
-        scp -q $_opt $KDUMP_LOG_FILE "$_host:$_dir/"
-        if [ $ret -ne 0 ]; then
-            return 1
-        fi
-        ssh $_opt $_host "mv $_dir/vmcore-incomplete $_dir/vmcore.flat" || return 1
     fi
 
+    if [ $_exitcode -eq 0 ]; then
+        ssh $_opt $_host "mv $_dir/vmcore-incomplete $_dir/$_vmcore"
+        _exitcode2=$?
+        if [ $_exitcode2 -ne 0 ]; then
+            derror "moving vmcore failed, _exitcode:$_exitcode2"
+        else
             dinfo "saving vmcore complete"
+        fi
+    else
+        derror "saving vmcore failed, _exitcode:$_exitcode"
+    fi
+
+    save_log
+    scp -q $_opt $KDUMP_LOG_FILE "$_host:$_dir/"
+    _ret=$?
+    if [ $_ret -ne 0 ]; then
+        derror "saving log file failed, _exitcode:$_ret"
+    fi
+
+    if [ $_exitcode -ne 0 ] || [ $_exitcode2 -ne 0 ];then
+        return 1
+    fi
+
     return 0
 }
 

kdump-lib-initramfs.sh

@@ -115,7 +115,7 @@ save_log()
 # dump_fs <mount point>
 dump_fs()
 {
-    local ret
+    local _exitcode
     local _mp=$1
     local _dev=$(get_mount_info SOURCE target $_mp -f)
     local _op=$(get_mount_info OPTIONS target $_mp -f)
@@ -159,16 +159,20 @@ dump_fs()
 
     dinfo "saving vmcore"
     $CORE_COLLECTOR /proc/vmcore $_dump_path/vmcore-incomplete
-    ret=$?
+    _exitcode=$?
-    save_log
+    if [ $_exitcode -eq 0 ]; then
-    mv $KDUMP_LOG_FILE $_dump_path/
-    if [ $ret -ne 0 ]; then
-	    return 1
-    fi
         mv $_dump_path/vmcore-incomplete $_dump_path/vmcore
         sync
-
         dinfo "saving vmcore complete"
+    else
+        derror "saving vmcore failed, _exitcode:$_exitcode"
+    fi
+
+    save_log
+    mv $KDUMP_LOG_FILE $_dump_path/
+    if [ $_exitcode -ne 0 ]; then
+        return 1
+    fi
 
     # improper kernel cmdline can cause the failure of echo, we can ignore this kind of failure
     return 0