[PATCH v3 storage 36/76] multipath: collect identities of non-iSCSI SCSI paths

[Thomas Lamprecht <t.lamprecht@proxmox.com>]

Fibre Channel paths need the same trusted WWID evidence as iSCSI paths,
but have no session target to group them by. Allow collection across
SCSI transports, treating each non-iSCSI path independently until its
identity is established.

Keep unresolved identities distinct from paths with no identity
evidence, so consumers do not mistake failed discovery for an absent
LUN.

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
---
 src/PVE/Multipath/Identity.pm      | 27 ++++++++++------
 src/test/run_lun_identity_tests.pl | 49 ++++++++++++++++++++++++++++++
 2 files changed, 67 insertions(+), 9 deletions(-)

diff --git a/src/PVE/Multipath/Identity.pm b/src/PVE/Multipath/Identity.pm
index 86141e98..3281c6d4 100644
--- a/src/PVE/Multipath/Identity.pm
+++ b/src/PVE/Multipath/Identity.pm
@@ -64,8 +64,13 @@ sub resolve($disks, $daemon, $naa_ok) {
     my $luns = {};
     for my $name (sort keys %$disks) {
         my $disk = $disks->{$name};
-        my $key = "$disk->{target}\0$disk->{lun}";
-        $luns->{$key} //= { target => $disk->{target}, lun => $disk->{lun}, paths => [] };
+        my $target = $disk->{target};
+        my $key = defined($target) ? "$target\0$disk->{lun}" : "\0$name";
+        $luns->{$key} //= {
+            defined($target) ? (target => $target) : (),
+            lun => $disk->{lun},
+            paths => [],
+        };
         push $luns->{$key}->{paths}->@*, $name;
     }
 
@@ -151,22 +156,26 @@ my sub lun_targets($sessions) {
     return $res;
 }
 
-my sub session_disks($sessions, $targets) {
+my sub scsi_disks($sessions, $targets, $all) {
     my $lun_target = lun_targets($sessions);
     my $res = {};
     dir_glob_foreach(
         "$SYSFS/bus/scsi/devices",
         '\d+:\d+:\d+:(\d+)',
         sub($hctl, $lun) {
-            my $target = $lun_target->{$hctl} // return;
-            return if $targets && !$targets->{$target};
+            my $target = $lun_target->{$hctl};
+            if (defined($target)) {
+                return if $targets && !$targets->{$target} && !$all;
+            } else {
+                return if !$all;
+            }
             my $dir = "bus/scsi/devices/$hctl";
             return if (sysfs_line("$dir/type") // '') ne '0'; # disks only
             my (undef, $name) = dir_glob_regex("$SYSFS/$dir/block", '([a-z]\S*)');
             return if !defined($name);
             my $devt = sysfs_line("$dir/block/$name/dev") // return;
-            my $disk =
-                { target => $target, lun => int($lun), devt => $devt, hctl => $hctl, dir => $dir };
+            my $disk = { lun => int($lun), devt => $devt, hctl => $hctl, dir => $dir };
+            $disk->{target} = $target if defined($target);
             # Read the holder through the SCSI device, so neither name can refer to another device
             # meanwhile.
             my (undef, $holder) = dir_glob_regex("$SYSFS/$dir/block/$name/holders", '(dm-\d+)');
@@ -182,7 +191,7 @@ my sub session_disks($sessions, $targets) {
 
 sub collect(%param) {
     my $sessions = iscsi_sessions();
-    my $disks = session_disks($sessions, $param{targets});
+    my $disks = scsi_disks($sessions, $param{targets}, $param{all});
 
     my ($daemon, $error);
     if (grep { !defined($_->{map}) } values %$disks) {
@@ -235,7 +244,7 @@ sub portals_covered($ids, $target, $portals) {
 }
 
 sub target_luns($ids, $target) {
-    return [grep { $_->{target} eq $target } values $ids->{luns}->%*];
+    return [grep { ($_->{target} // '') eq $target } values $ids->{luns}->%*];
 }
 
 # The WWID of the LUN of the path $name in $ids, if it was resolved and the name still denotes the
diff --git a/src/test/run_lun_identity_tests.pl b/src/test/run_lun_identity_tests.pl
index 4e9507a0..9f89c923 100755
--- a/src/test/run_lun_identity_tests.pl
+++ b/src/test/run_lun_identity_tests.pl
@@ -881,4 +881,53 @@ $rows = PVE::Multipath::Status::aggregate_cluster_status(
 );
 ok($rows->[0]->{'not-observed'}, 'end to end: the last LUN of a target retired, not observed');
 
+# --- paths of other transports ---
+
+{
+    # a Fibre Channel LUN on host 20, on a node without any iSCSI session: each path counts on
+    # its own
+    $identity->unmock_all();
+    my $iscsi_sys = $sys;
+    $sys = tempdir(CLEANUP => 1);
+    $PVE::Multipath::Identity::SYSFS = $sys;
+    make_path("$sys/class/iscsi_session");
+    disk_device('20:0:0:0', 'sdg', '8:96');
+    disk_device('20:0:1:0', 'sdh', '8:112');
+    $queries = 0;
+    $reply = {
+        sdg => {
+            devt => '8:96',
+            hctl => '20:0:0:0',
+            init => 'ok',
+            target => '0x200',
+            wwid => 'SFC_LUN',
+        },
+        sdh => {
+            devt => '8:112',
+            hctl => '20:0:1:0',
+            init => 'ok',
+            target => '0x201',
+            wwid => 'SFC_LUN',
+        },
+    };
+    my $ids = PVE::Multipath::Identity::collect(targets => {});
+    is(
+        PVE::Multipath::Identity::path_wwid($ids, 'sdg'),
+        undef,
+        'other transports: not without asking for them',
+    );
+    $ids = PVE::Multipath::Identity::collect(all => 1);
+    is_deeply(
+        [map { PVE::Multipath::Identity::path_wwid($ids, $_) } qw(sdg sdh)],
+        ['SFC_LUN', 'SFC_LUN'],
+        'other transports: every path identified on its own',
+    );
+    is(
+        scalar(grep { !defined($_->{target}) } values $ids->{luns}->%*),
+        2,
+        'other transports: as LUNs of their own, as nothing groups the paths',
+    );
+    ($sys, $PVE::Multipath::Identity::SYSFS) = ($iscsi_sys, $iscsi_sys);
+}
+
 done_testing();
-- 
2.47.3