[PATCH v4 6/8] mkdumprd: omit dracut modules in case of no dm target

[Xunlei Pang]

In case of on dm related target, we can clearly and safely
remove many unnecessary modules to reduce initramfs size,
and to enhance stability.

Signed-off-by: Xunlei Pang <xlpang(a)redhat.com&gt;
---
v3->v4:
-Rebased due to previos change.

 mkdumprd | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/mkdumprd b/mkdumprd
index 644b5ce..9c5339c 100644
--- a/mkdumprd
+++ b/mkdumprd
@@ -372,16 +372,44 @@ check_crypt()
     return 1
 }
 
+is_dm()
+{
+    if [ -d "/sys/dev/block/$1/dm" ]; then
+        return 0
+    fi
+
+    return 1
+}
+
 crypt_exists=0
 omit_dracut_modules()
 {
+    local target majmin
+    local dm_exists
+
     # Skip fadump case
     is_fadump_capable && return
 
+    dm_exists=0
+
+    for target in $(get_kdump_targets); do
+        if [ -b "$target" ]; then
+            majmin=$(get_maj_min $target)
+            # Check "dm"
+            check_block_and_slaves is_dm $majmin && dm_exists=1
+        fi
+    done
+
     # Omit "crypt", BZ1451717
     if [ "$crypt_exists" == "0" ]; then
         add_dracut_arg "--omit" "crypt"
     fi
+
+    # Further omit more modules in case of no dm related target
+    if [ "$dm_exists" == "0" ]; then
+        # "dm_exists=0" implies "crypt_exists=0"
+        add_dracut_arg "--omit" "lvm dm multipath dmraid"
+    fi
 }
 
 if ! check_resettable; then
-- 
1.8.3.1