diff --git a/RHEL-173130-iSCSILogicalUnit-add-block-size-override-and-backstore-type-selection.patch b/RHEL-173130-iSCSILogicalUnit-add-block-size-override-and-backstore-type-selection.patch
new file mode 100644
index 0000000..7f4ea4c
--- /dev/null
+++ b/RHEL-173130-iSCSILogicalUnit-add-block-size-override-and-backstore-type-selection.patch
@@ -0,0 +1,160 @@
+--- a/heartbeat/iSCSILogicalUnit.in 2021-11-03 10:12:01.000000000 +0100
++++ b/heartbeat/iSCSILogicalUnit.in 2026-05-28 14:25:31.007210780 +0200
+@@ -67,6 +67,8 @@
+ # Set LIO-T backend default as 'block'
+ OCF_RESKEY_liot_bstype_default="block"
+ : ${OCF_RESKEY_liot_bstype=${OCF_RESKEY_liot_bstype_default}}
++OCF_RESKEY_block_size_default=""
++: ${OCF_RESKEY_block_size=${OCF_RESKEY_block_size_default}}
+
+ ## tgt specifics
+ # tgt has "backing store type" and "backing store open flags",
+@@ -186,6 +188,19 @@
+
+
+
++
++
++Enable or disable write-back caching for this Logical Unit.
++Setting to 1 enables write-back caching (the default for fileio
++backstores). Setting to 0 disables it, enabling write-through mode.
++Write-through mode is recommended for HA configurations to ensure
++data is flushed to disk before the iSCSI write is acknowledged.
++Requires the lio-t implementation.
++
++Write-back cache (0 or 1)
++
++
++
+
+
+ The SCSI vendor ID to be configured for this Logical Unit.
+@@ -292,6 +307,19 @@
+
+
+
++
++
++Override the block size presented to initiators for this
++Logical Unit. Accepted values are 512, 1024, 2048, or 4096.
++This sets the block_size attribute in the LIO kernel target
++(configfs) or the blocksize attribute in SCST.
++Requires the lio-t implementation.
++If unset, the kernel default (typically 512) is used.
++
++Block size (512, 1024, 2048, or 4096)
++
++
++
+
+
+
+@@ -428,7 +456,13 @@
+ lio-t)
+ ocf_take_lock $TARGETLOCKFILE
+ ocf_release_lock_on_exit $TARGETLOCKFILE
+- iblock_attrib_path="/sys/kernel/config/target/core/iblock_*/${OCF_RESOURCE_INSTANCE}/attrib"
++ # Map liot_bstype to the configfs core directory name
++ case "${OCF_RESKEY_liot_bstype}" in
++ block) liot_configfs_core="iblock_*" ;;
++ fileio) liot_configfs_core="fileio_*" ;;
++ pscsi) liot_configfs_core="pscsi_*" ;;
++ esac
++ liot_core_path="/sys/kernel/config/target/core/${liot_configfs_core}/${OCF_RESOURCE_INSTANCE}"
+ # For lio, we first have to create a target device, then
+ # add it to the Target Portal Group as an LU.
+ # Handle differently 'block', 'fileio' and 'pscsi'
+@@ -445,10 +479,13 @@
+ ocf_run targetcli /backstores/${OCF_RESKEY_liot_bstype} create ${OCF_RESOURCE_INSTANCE} ${OCF_RESKEY_path} || exit $OCF_ERR_GENERIC
+ fi
+ if [ -n "${OCF_RESKEY_scsi_sn}" ]; then
+- echo ${OCF_RESKEY_scsi_sn} > /sys/kernel/config/target/core/iblock_*/${OCF_RESOURCE_INSTANCE}/wwn/vpd_unit_serial
++ echo ${OCF_RESKEY_scsi_sn} > ${liot_core_path}/wwn/vpd_unit_serial
+ fi
+ if [ -n "${OCF_RESKEY_product_id}" ]; then
+- echo "${OCF_RESKEY_product_id}" > /sys/kernel/config/target/core/iblock_*/${OCF_RESOURCE_INSTANCE}/wwn/product_id
++ echo "${OCF_RESKEY_product_id}" > ${liot_core_path}/wwn/product_id
++ fi
++ if [ -n "${OCF_RESKEY_block_size}" ]; then
++ echo ${OCF_RESKEY_block_size} > ${liot_core_path}/attrib/block_size || exit $OCF_ERR_GENERIC
+ fi
+
+ ocf_run targetcli /iscsi/${OCF_RESKEY_target_iqn}/tpg1/luns create /backstores/${OCF_RESKEY_liot_bstype}/${OCF_RESOURCE_INSTANCE} ${OCF_RESKEY_lun} || exit $OCF_ERR_GENERIC
+@@ -470,13 +507,16 @@
+ fi
+
+ if [ -n "${OCF_RESKEY_emulate_tpu}" ]; then
+- echo ${OCF_RESKEY_emulate_tpu} > ${iblock_attrib_path}/emulate_tpu || exit $OCF_ERR_GENERIC
++ echo ${OCF_RESKEY_emulate_tpu} > ${liot_core_path}/attrib/emulate_tpu || exit $OCF_ERR_GENERIC
+ fi
+ if [ -n "${OCF_RESKEY_emulate_3pc}" ]; then
+- echo ${OCF_RESKEY_emulate_3pc} > ${iblock_attrib_path}/emulate_3pc || exit $OCF_ERR_GENERIC
++ echo ${OCF_RESKEY_emulate_3pc} > ${liot_core_path}/attrib/emulate_3pc || exit $OCF_ERR_GENERIC
+ fi
+ if [ -n "${OCF_RESKEY_emulate_caw}" ]; then
+- echo ${OCF_RESKEY_emulate_caw} > ${iblock_attrib_path}/emulate_caw || exit $OCF_ERR_GENERIC
++ echo ${OCF_RESKEY_emulate_caw} > ${liot_core_path}/attrib/emulate_caw || exit $OCF_ERR_GENERIC
++ fi
++ if [ -n "${OCF_RESKEY_emulate_write_cache}" ]; then
++ echo ${OCF_RESKEY_emulate_write_cache} > ${liot_core_path}/attrib/emulate_write_cache || exit $OCF_ERR_GENERIC
+ fi
+ ;;
+ esac
+@@ -604,9 +644,14 @@
+ configfs_path="/sys/kernel/config/target/iscsi/${OCF_RESKEY_target_iqn}/tpgt_1/lun/lun_${OCF_RESKEY_lun}/*/udev_path"
+ [ -e ${configfs_path} ] && [ `cat ${configfs_path}` = "${OCF_RESKEY_path}" ] && return $OCF_SUCCESS
+
+- # if we aren't activated, is a block device still left over?
+- block_configfs_path="/sys/kernel/config/target/core/iblock_*/${OCF_RESOURCE_INSTANCE}/udev_path"
+- [ -e ${block_configfs_path} ] && ocf_log warn "existing block without an active lun: ${block_configfs_path}"
++ # if we aren't activated, is a backstore still left over?
++ case "${OCF_RESKEY_liot_bstype}" in
++ block) liot_configfs_core="iblock_*" ;;
++ fileio) liot_configfs_core="fileio_*" ;;
++ pscsi) liot_configfs_core="pscsi_*" ;;
++ esac
++ block_configfs_path="/sys/kernel/config/target/core/${liot_configfs_core}/${OCF_RESOURCE_INSTANCE}/udev_path"
++ [ -e ${block_configfs_path} ] && ocf_log warn "existing backstore without an active lun: ${block_configfs_path}"
+ [ -e ${block_configfs_path} ] && return $OCF_ERR_GENERIC
+ ;;
+ esac
+@@ -624,6 +669,22 @@
+ fi
+ done
+
++ # Validate block_size if set
++ if [ -n "${OCF_RESKEY_block_size}" ]; then
++ case "${OCF_RESKEY_block_size}" in
++ 512|1024|2048|4096)
++ ;;
++ *)
++ ocf_exit_reason "Invalid block_size ${OCF_RESKEY_block_size} (must be 512, 1024, 2048, or 4096)"
++ exit $OCF_ERR_CONFIGURED
++ ;;
++ esac
++ if [ "${OCF_RESKEY_implementation}" != "lio-t" ]; then
++ ocf_exit_reason "block_size is only supported with the lio-t implementation"
++ exit $OCF_ERR_CONFIGURED
++ fi
++ fi
++
+ # Is the configured implementation supported?
+ case "$OCF_RESKEY_implementation" in
+ "iet"|"tgt"|"lio"|"lio-t")
+@@ -689,13 +750,13 @@
+ iet)
+ # IET does not support setting the vendor and product ID
+ # (it always uses "IET" and "VIRTUAL-DISK")
+- unsupported_params="vendor_id product_id allowed_initiators lio_iblock tgt_bstype tgt_bsoflags tgt_bsopts tgt_device_type emulate_tpu emulate_3pc emulate_caw liot_bstype"
++ unsupported_params="vendor_id product_id allowed_initiators lio_iblock tgt_bstype tgt_bsoflags tgt_bsopts tgt_device_type emulate_tpu emulate_3pc emulate_caw emulate_write_cache liot_bstype"
+ ;;
+ tgt)
+- unsupported_params="allowed_initiators lio_iblock emulate_tpu emulate_3pc emulate_caw liot_bstype"
++ unsupported_params="allowed_initiators lio_iblock emulate_tpu emulate_3pc emulate_caw emulate_write_cache liot_bstype"
+ ;;
+ lio)
+- unsupported_params="scsi_id vendor_id product_id tgt_bstype tgt_bsoflags tgt_bsopts tgt_device_type emulate_tpu emulate_3pc emulate_caw liot_bstype"
++ unsupported_params="scsi_id vendor_id product_id tgt_bstype tgt_bsoflags tgt_bsopts tgt_device_type emulate_tpu emulate_3pc emulate_caw emulate_write_cache liot_bstype"
+ ;;
+ lio-t)
+ unsupported_params="scsi_id vendor_id tgt_bstype tgt_bsoflags tgt_bsopts tgt_device_type lio_iblock"
diff --git a/resource-agents.spec b/resource-agents.spec
index 2e3b1c4..d4ea1ab 100644
--- a/resource-agents.spec
+++ b/resource-agents.spec
@@ -45,7 +45,7 @@
Name: resource-agents
Summary: Open Source HA Reusable Cluster Resource Scripts
Version: 4.10.0
-Release: 119%{?rcver:%{rcver}}%{?numcomm:.%{numcomm}}%{?alphatag:.%{alphatag}}%{?dirty:.%{dirty}}%{?dist}
+Release: 120%{?rcver:%{rcver}}%{?numcomm:.%{numcomm}}%{?alphatag:.%{alphatag}}%{?dirty:.%{dirty}}%{?dist}
License: GPLv2+ and LGPLv2+
URL: https://github.com/ClusterLabs/resource-agents
Source0: %{upstream_prefix}-%{upstream_version}.tar.gz
@@ -214,6 +214,7 @@ Patch161: RHEL-177840-podman-etcd-fix-machine-deletion-deadlock.patch
Patch162: RHEL-177845-podman-etcd-fix-learner-start-deadlock.patch
Patch163: RHEL-150842-pgsqlms-use-monitor_user-for-monitor-calls-and-use-pgpass-when-monitor_password-is-not-specified.patch
Patch164: RHEL-179069-IPaddr2-fix-interfaces-named-with-keywords.patch
+Patch165: RHEL-173130-iSCSILogicalUnit-add-block-size-override-and-backstore-type-selection.patch
# bundled ha-cloud-support libs
Patch500: ha-cloud-support-aliyun.patch
@@ -523,6 +524,7 @@ exit 1
%patch -p1 -P 162
%patch -p1 -P 163
%patch -p1 -P 164
+%patch -p1 -P 165
# bundled ha-cloud-support libs
%patch -p1 -P 500
@@ -857,6 +859,11 @@ rm -rf %{buildroot}/usr/share/doc/resource-agents
%{_usr}/lib/ocf/lib/heartbeat/OCF_*.pm
%changelog
+* Thu May 28 2026 Oyvind Albrigtsen - 4.10.0-120
+- iSCSILogicalUnit: add block size override and backstore type selection
+
+ Resolves: RHEL-173130
+
* Wed May 27 2026 Oyvind Albrigtsen - 4.10.0-119
- IPaddr2: fix interfaces named with keywords like primary, secondary,
etc