zdev/dracut: add rd.zfcp cmdline option handling

Add parsing of dracut cmdline option "rd.zfcp=..." at initrd runtime.
It delegates configuration to chzdev.

Implement `dracut --print-cmdline` and `dracut --hostonly-cmdline` for
initrd build time. Emit an rd.zfcp option for each zfcp-attached SCSI disk
in dracut's device dependency graph (to mount the root-fs, or to access the
kdump target).

This allows a distribution independent device configuration.
Configuration is consistent by using chzdev as backend.
It also prevents duplicate activations of the same device.

Along with the existing functionality of zdev/dracut, it makes the
following dracut modules superfluous:
https://github.com/dracutdevs/dracut/tree/master/modules.d/95zfcp
[rd.zfcp.conf is no longer needed and thus ignored here; the preceding
 ("zdev/dracut: fix marking hostonly files so delete option works")
 makes rd.hostonly=0 work as a generic replacement]
https://github.com/dracutdevs/dracut/tree/master/modules.d/95zfcp_rules

Github-ID: #158
Acked-by: Vineeth Vijayan <vneethv@linux.ibm.com>
Acked-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Signed-off-by: Steffen Maier <maier@linux.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>

zdev/dracut/95zdev-kdump/module-setup.sh

@@ -8,7 +8,8 @@
 #
 # 95zdev-kdump/module_setup.sh
 #   This module installs configuration files (udev rules and modprobe.conf
-#   files) required to enable the kdump target on s390.
+#   files) required to enable the kdump target on s390. In addition,
+#   a hook is installed to parse rd.zfcp= kernel parameters.
 #
 
 # called by dracut
@@ -26,6 +27,7 @@ check() {
 
     # Ensure that required tools are available
     require_binaries chzdev lszdev || return 1
+    require_binaries grep sort uniq || return 1
 
     return 0
 }
@@ -35,6 +37,19 @@ depends() {
     return 0
 }
 
+# called by dracut and (conditionally) locally by install()
+# Generate rd.zfcp dracut cmdline options for each zfcp-attached
+# SCSI disk in dracut's device dependency graph (to mount the root-fs,
+# or to access the kdump target). With "dracut --print-cmdline", dracut
+# prints the list. With "dracut --hostonly-cmdline", dracut stores the
+# list inside the generated initrd.
+cmdline() {
+    # shellcheck disable=SC2154
+    if [[ $hostonly ]]; then
+        for_each_host_dev_and_slaves_all zdev_check_dev | sort | uniq
+    fi
+}
+
 # called by dracut
 installkernel() {
     # Add modules for all device types supported by chzdev (required for
@@ -51,8 +66,22 @@ install() {
     # installing avoids error messages from zdev site udev rule processing
     inst_multiple -o /lib/s390-tools/zdev_id
 
+    # Ensure that required tools are available
+    inst_multiple chzdev grep
+
+    # Hook to parse zfcp dracut cmdline parameter
+    inst_hook cmdline 95 "$moddir/../95zdev/parse-zfcp.sh"
+
     # Obtain kdump target device configuration
 
+    # shellcheck disable=SC2154
+    if [[ $hostonly_cmdline == "yes" ]]; then
+        local _rdsomedev
+        for _rdsomedev in $(cmdline); do
+            printf "%s\n" "$_rdsomedev" >> "${initdir:?}/etc/cmdline.d/94zdev.conf"
+        done
+    fi
+
     _tempfile=$(mktemp --tmpdir dracut-zdev.XXXXXX)
 
     # work with systems that are not based on chzdev persistent config

zdev/dracut/95zdev/module-setup.sh

@@ -1,6 +1,6 @@
 #!/bin/bash
 #
-# Copyright IBM Corp. 2016, 2017
+# Copyright IBM Corp. 2016, 2023
 #
 # s390-tools is free software; you can redistribute it and/or modify
 # it under the terms of the MIT license. See LICENSE for details.
@@ -10,7 +10,7 @@
 #   This module installs configuration files (udev rules and modprobe.conf
 #   files) required to enable the root device on s390. It will only work when
 #   the root device was configured using the chzdev tool. In addition,
-#   a hook is installed to parse rd.zdev= kernel parameters.
+#   hooks are installed to parse rd.zdev= and rd.zfcp= kernel parameters.
 #
 
 # called by dracut
@@ -31,6 +31,7 @@ check() {
     # Ensure that required tools are available
     require_binaries chzdev lszdev /lib/s390-tools/zdev_id || return 1
     require_binaries sed || return 1
+    require_binaries grep sort uniq || return 1
 
     return 0
 }
@@ -40,6 +41,20 @@ depends() {
     return 0
 }
 
+# called by dracut and (conditionally) locally by install()
+# Generate rd.zfcp dracut cmdline options for each zfcp-attached
+# SCSI disk in dracut's device dependency graph (to mount the root-fs,
+# or to access the kdump target). With "dracut --print-cmdline", dracut
+# prints the list. With "dracut --hostonly-cmdline" [the case where
+# install() calls cmdline()], dracut stores the list inside the generated
+# initrd.
+cmdline() {
+    # shellcheck disable=SC2154
+    if [[ $hostonly ]]; then
+        for_each_host_dev_and_slaves_all zdev_check_dev | sort | uniq
+    fi
+}
+
 # called by dracut
 installkernel() {
     # Add modules for all device types supported by chzdev (required for
@@ -55,15 +70,26 @@ install() {
 
     # Ensure that required tools are available
     inst_multiple chzdev lszdev vmcp /lib/s390-tools/zdev_id
+    inst_multiple grep
 
     # Hook to parse zdev kernel parameter
     inst_hook cmdline 95 "$moddir/parse-zdev.sh"
+    # Hook to parse zfcp dracut cmdline parameter
+    inst_hook cmdline 95 "$moddir/parse-zfcp.sh"
 
     # Rule to automatically enable devices when running in DPM
     inst_rules "81-dpm.rules"
 
     # Obtain early + root device configuration
 
+    # shellcheck disable=SC2154
+    if [[ $hostonly_cmdline == "yes" ]]; then
+        local _rdsomedev
+        for _rdsomedev in $(cmdline); do
+            printf "%s\n" "$_rdsomedev" >> "${initdir:?}/etc/cmdline.d/94zdev.conf"
+        done
+    fi
+
     # If enabled, add the host-specific config of required devices into initrd
     # shellcheck disable=SC2154
     [[ $hostonly ]] || return 0

zdev/dracut/95zdev/parse-zfcp.sh

@@ -0,0 +1,35 @@
+#!/bin/sh
+#
+# Copyright IBM Corp. 2023
+#
+# s390-tools is free software; you can redistribute it and/or modify
+# it under the terms of the MIT license. See LICENSE for details.
+#
+# 95zdev/parse-zfcp.sh
+#   Parse the command line for rd.zfcp parameters. These
+#   parameters are evaluated and used to configure zfcp devices.
+#
+
+zdev_zfcp_base_args="--no-settle --yes --quiet --no-root-update --force"
+
+for zdev_zfcp_arg in $(getargs rd.zfcp -d 'rd_ZFCP='); do
+    (
+        IFS_SAVED="$IFS"
+        IFS="," # did not work in front of built-in set command below
+        # shellcheck disable=SC2086
+        set -- $zdev_zfcp_arg
+        IFS=":" args="$*"
+        IFS="$IFS_SAVED"
+        if [ "$#" -eq 1 ]; then
+            # shellcheck disable=SC2086
+            chzdev --enable --persistent $zdev_zfcp_base_args \
+                   zfcp-host "$args"
+        else
+            # shellcheck disable=SC2086
+            chzdev --enable --persistent $zdev_zfcp_base_args \
+                   zfcp-lun "$args"
+        fi
+    )
+done
+unset zdev_zfcp_arg
+unset zdev_zfcp_base_args

zdev/dracut/95zdev/zdev-lib.sh

@@ -25,3 +25,78 @@ zdev_is_kdump() {
     fi
     return 1
 }
+
+zdev_zfcp_auto_lun_scan_active() {
+    local _fcpdevsysfs=$1
+    local _porttype _lunscan
+    read -r _porttype < "$_fcpdevsysfs"/host*/fc_host/host*/port_type
+    read -r _lunscan < /sys/module/zfcp/parameters/allow_lun_scan
+    if [[ "$_porttype" == "NPIV VPORT" && "$_lunscan" == "Y" ]]; then
+        return 0
+    fi
+    return 1
+}
+
+# zdev_check_dev() can be extended for other device types such as DASD or PCIe
+zdev_check_dev() {
+    local _dev=$1
+    local _devsysfs _devtype _subsystem _driver
+    local _intlun _fcplun _scsitarget _wwpn _hbaid
+    _devsysfs=$(
+        cd -P /sys/dev/block/"$_dev" 2> /dev/null && echo "$PWD"
+             )
+    # This is roughly what systemd's udev-builtin-path_id does for zfcp:
+    while [[ -n "$_devsysfs" ]]; do
+        # ascend to parent: strip last path part
+        _devsysfs=${_devsysfs%/*}
+        _subsystem=$(
+            cd -P "$_devsysfs"/subsystem 2> /dev/null && echo "$PWD"
+              )
+        if [[ "${_subsystem##*/}" == "scsi" ]]; then
+            _devtype=$(grep "^DEVTYPE=" "$_devsysfs"/uevent)
+            # check for FCP LUN
+            if [[ "$_devtype" == "DEVTYPE=scsi_device" ]]; then
+                _intlun=${_devsysfs##*:}
+                # convert _intlun to _fcplun [int_to_scsilun()]
+                _fcplun=0
+                ((_fcplun |= (_intlun & 0x000000000000ffff) << 48))
+                ((_fcplun |= (_intlun & 0x00000000ffff0000) << 16))
+                ((_fcplun |= (_intlun & 0x0000ffff00000000) >> 16))
+                ((_fcplun |= (_intlun & 0xffff000000000000) >> 48))
+                printf -v _fcplun "0x%016x" "$_fcplun"
+                # bail out if not scsi_transport_fc
+                [[ "${_devsysfs/*rport-*/FOUND}" == "FOUND" ]] || return 0
+                continue
+            fi
+            # check for target WWPN
+            if [[ "$_devtype" == "DEVTYPE=scsi_target" ]]; then
+                _scsitarget=${_devsysfs##*/}
+                read -r _wwpn < "$_devsysfs/fc_transport/$_scsitarget/port_name"
+                continue
+            fi
+        fi
+        if [[ "${_subsystem##*/}" == "ccw" ]]; then
+            _driver=$(
+                cd -P "$_devsysfs"/driver 2> /dev/null && echo "$PWD"
+                  )
+            # check for FCP device (vHBA) bus-ID
+            if [[ "${_driver##*/}" == "zfcp" ]]; then
+                _hbaid=${_devsysfs##*/}
+                # drop full path and use zfcp auto LUN scan, if:
+                # - not building for kdump which has zfcp auto LUN scan off
+                # - and zfcp auto LUN scan is available
+                if ! zdev_is_kdump && \
+                        zdev_zfcp_auto_lun_scan_active "$_devsysfs"; then
+                    unset _wwpn
+                    unset _fcplun
+                fi
+                if [[ -n "$_wwpn" ]] && [[ -n "$_fcplun" ]]; then
+                    printf " rd.zfcp=%s,%s,%s\n" "$_hbaid" "$_wwpn" "$_fcplun"
+                else
+                    printf " rd.zfcp=%s\n" "$_hbaid"
+                fi
+                break
+            fi
+        fi
+    done
+}

zdev/dracut/Makefile

@@ -21,6 +21,7 @@ install:
 	$(INSTALL) -m 755 $(ZDEVDIR)/module-setup.sh \
 		$(ZDEVDIR)/parse-zdev.sh \
 		$(ZDEVDIR)/zdev-lib.sh \
+		$(ZDEVDIR)/parse-zfcp.sh \
 		$(DESTDIR)$(DRACUTMODDIR)/$(ZDEVDIR)/
 	$(INSTALL) -m 755 -d $(DESTDIR)$(DRACUTMODDIR)/$(ZDEVKDUMPDIR)
 	$(INSTALL) -m 755 $(ZDEVKDUMPDIR)/module-setup.sh \