From 32ab91e528798e88f600c2015466adc729d788ec Mon Sep 17 00:00:00 2001
From: Peter Rajnoha <prajnoha@redhat.com>
Date: Mon, 9 Dec 2024 13:05:03 +0100
Subject: [PATCH] udev: create /dev/disk/by-diskseq/<DISKSEQ> symlink for
 public DM devices

All block devices have a disk sequence number assigned (an ever-increasing 64 bit
sequence number) since kernel v5.15 (February 2021). The number is exported through
/sys/block/<disk>/diskseq property and also as DISKSEQ udev event variable.
The diskseq helps with referencing a device throughout its existence in
race-free way.

By default, the /usr/lib/udev/rules.d/60-persistent-storage.rules set
/dev/disk/by-diskseq/<diskseq> symlink for each block device. However,
these rules do not apply for DM devices because we manage the symlinks
ourselves in 13-dm-disk.rules where it properly follows the
DM_UDEV_DISABLE_DISK_RULES flag, among other things.

Add a rule to 13-dm-disk.rules to create the /dev/disk/by-diskseq/<diskseq>.
---
 WHATS_NEW_DM             | 1 +
 udev/13-dm-disk.rules.in | 2 ++
 2 files changed, 3 insertions(+)

diff --git a/WHATS_NEW_DM b/WHATS_NEW_DM
index f4e796cac..c5fa162f1 100644
--- a/WHATS_NEW_DM
+++ b/WHATS_NEW_DM
@@ -1,5 +1,6 @@
 Version 1.02.204 - 
 ===================
+  Create /dev/disk/by-diskseq/<DISKSEQ> symlink for public DM devices.
 
 Version 1.02.203 - 09th December 2024
 =====================================
diff --git a/udev/13-dm-disk.rules.in b/udev/13-dm-disk.rules.in
index 03ea203ee..9bfeebe13 100644
--- a/udev/13-dm-disk.rules.in
+++ b/udev/13-dm-disk.rules.in
@@ -17,6 +17,8 @@ ENV{DM_UDEV_DISABLE_DISK_RULES_FLAG}=="1", GOTO="dm_end"
 SYMLINK+="disk/by-id/dm-name-$env{DM_NAME}"
 ENV{DM_UUID}=="?*", SYMLINK+="disk/by-id/dm-uuid-$env{DM_UUID}"
 
+ENV{DISKSEQ}=="?*", SYMLINK+="disk/by-diskseq/$env{DISKSEQ}"
+
 ENV{.DM_SUSPENDED}=="1", ENV{DM_UDEV_PRIMARY_SOURCE_FLAG}=="1", GOTO="dm_import"
 ENV{.DM_NOSCAN}=="1", ENV{DM_UDEV_PRIMARY_SOURCE_FLAG}=="1", GOTO="dm_import"
 ENV{.DM_SUSPENDED}=="1", GOTO="dm_end"