From b5a9e5462938fdca2f3083935b02786f814d2ca1 Mon Sep 17 00:00:00 2001
From: Tao Liu <ltao@redhat.com>
Date: Oct 26 2022 02:16:16 +0000
Subject: Seperate dracut and dracut-squash compressor for zstd


Upstream: fedora
Resolves: bz2045949
Resolves: bz2044804
Conflict: none

commit fc1c79ffd21e7bcb3a710368cd7023c9a634258e
Author: Tao Liu <ltao@redhat.com>
Date:   Sat Oct 8 12:09:08 2022 +0800

    Seperate dracut and dracut-squash compressor for zstd

    Previously kexec-tools will pass "--compress zstd" to dracut. It
    will make dracut to decide whether: a) call mksquashfs to make a
    zstd format squash-root.img, b) call cmd zstd to make a initramfs.

    Since dracut(>= 057) has decoupled the compressor for dracut and
    dracut-squash, So in this patch, we will pass the compressor seperately.

    Note:

    The is_squash_available && !dracut_has_option --squash-compressor
    && !is_zsdt_command_available case is left unprocessed on purpose.

    Actually, the situation when we want to call zstd compression is:
    1) If squash function OK, we want dracut to invoke mksquashfs to make
    a zstd format squash-root.img within initramfs.
    2) If squash function is not OK, and cmd zstd presents, we want dracut
    to invoke cmd zstd to make a zstd format initramfs.

    is_zstd_command_available check can handle case 2 completely.

    However, for the is_squash_available check, it cannot handle case 1
    completely. It only checks if the kernel supports squashfs, it doesn't
    check whether the squash module has been added by dracut when making
    initramfs. In fact, in kexec-tools we are unable to do the check,
    there are multiple ways to forbit dracut to load a module, such as
    "dracut -o module" and "omit_dracutmodules in dracut.conf".

    When squash dracut module is omitted, is_squash_available check will
    still pass, so "--compress zstd" will be appended to dracut cmdline,
    and it will call cmd zstd to do the compression. However cmd zstd may
    not exist, so it fails.

    The previous "--compress zstd" is ambiguous, after the intro of
    "--squash-compressor", "--squash-compressor" only effect for
    mksquashfs and "--compress" only effect for specific cmd.

    So for the is_squash_available && !dracut_has_option
    --squash-compressor && !is_zsdt_command_available case, we just leave
    it to be handled the default way.

    Reviewed-by: Philipp Rudo <prudo@redhat.com>
    Signed-off-by: Tao Liu <ltao@redhat.com>

Signed-off-by: Tao Liu <ltao@redhat.com>

---

diff --git a/kdump-lib.sh b/kdump-lib.sh
index a15496b..9a64f50 100755
--- a/kdump-lib.sh
+++ b/kdump-lib.sh
@@ -34,6 +34,12 @@ is_zstd_command_available()
 	[[ -x "$(command -v zstd)" ]]
 }
 
+dracut_have_option()
+{
+	local _option=$1
+	! dracut "$_option" 2>&1 | grep -q "unrecognized option"
+}
+
 perror_exit()
 {
 	derror "$@"
@@ -448,8 +454,7 @@ is_wdt_active()
 
 have_compression_in_dracut_args()
 {
-	[[ "$(kdump_get_conf_val dracut_args)" =~ \
-		(^|[[:space:]])--(gzip|bzip2|lzma|xz|lzo|lz4|zstd|no-compress|compress)([[:space:]]|$) ]]
+	[[ "$(kdump_get_conf_val dracut_args)" =~ (^|[[:space:]])--(gzip|bzip2|lzma|xz|lzo|lz4|zstd|no-compress|compress|squash-compressor)([[:space:]]|$) ]]
 }
 
 # If "dracut_args" contains "--mount" information, use it
diff --git a/kexec-tools.spec b/kexec-tools.spec
index 013cc47..1e888d3 100644
--- a/kexec-tools.spec
+++ b/kexec-tools.spec
@@ -71,7 +71,6 @@ Requires: dracut >= 050
 Requires: dracut-network >= 050
 Requires: dracut-squash >= 050
 Requires: ethtool
-Recommends: zstd
 Recommends: grubby
 Recommends: hostname
 BuildRequires: make
diff --git a/mkdumprd b/mkdumprd
index 82fbc61..8550961 100644
--- a/mkdumprd
+++ b/mkdumprd
@@ -432,10 +432,9 @@ done <<< "$(kdump_read_conf)"
 handle_default_dump_target
 
 if ! have_compression_in_dracut_args; then
-	# Here zstd is set as the default compression method. If squash module
-	# is available for dracut, libzstd will be used by mksquashfs. If
-	# squash module is unavailable, command zstd will be used instead.
-	if is_squash_available || is_zstd_command_available; then
+	if is_squash_available && dracut_have_option "--squash-compressor"; then
+		add_dracut_arg "--squash-compressor" "zstd"
+	elif is_zstd_command_available; then
 		add_dracut_arg "--compress" "zstd"
 	fi
 fi
diff --git a/mkfadumprd b/mkfadumprd
index 86dfcee..f353f15 100644
--- a/mkfadumprd
+++ b/mkfadumprd
@@ -64,7 +64,9 @@ fi
 
 # Same as setting zstd in mkdumprd
 if ! have_compression_in_dracut_args; then
-	if is_squash_available || is_zstd_command_available; then
+	if is_squash_available && dracut_have_option "--squash-compressor"; then
+		_dracut_isolate_args+=(--squash-compressor zstd)
+	elif is_zstd_command_available; then
 		_dracut_isolate_args+=(--compress zstd)
 	fi
 fi