rbd: fix #3969: add rbd dev paths with cluster info

By adding our own customized rbd udev rules and ceph-rbdnamer we can
create device paths that include the cluster fsid and avoid any
ambiguity if the same pool and namespace combination is used in
different clusters we connect to.

Additionally to the '/dev/rbd/<pool>/...' paths we now have
'/dev/rbd-pve/<cluster fsid>/<pool>/...' paths.

The other half of the patch makes use of the new device paths in the RBD
plugin.

The new 'get_rbd_dev_path' method the full device path. In case that the
image has been mapped before the rbd-pve udev rule has been installed,
it returns the old path.

The cluster fsid is read from the 'ceph.conf' file in the case of a
hyperconverged setup. In the case of an external Ceph cluster we need to
fetch it via a rados api call.

Co-authored-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
Signed-off-by: Aaron Lauterer <a.lauterer@proxmox.com>

Makefile

@@ -41,6 +41,7 @@ install: PVE pvesm.1 pvesm.bash-completion pvesm.zsh-completion
 	install -d ${DESTDIR}${SBINDIR}
 	install -m 0755 pvesm ${DESTDIR}${SBINDIR}
 	make -C PVE install
+	make -C udev-rbd install
 	install -d ${DESTDIR}/usr/share/man/man1
 	install -m 0644 pvesm.1 ${DESTDIR}/usr/share/man/man1/
 	gzip -9 -n ${DESTDIR}/usr/share/man/man1/pvesm.1

PVE/Storage/RBDPlugin.pm

@@ -8,6 +8,7 @@ use JSON;
 use Net::IP;
 
 use PVE::CephConfig;
+use PVE::Cluster qw(cfs_read_file);;
 use PVE::JSONSchema qw(get_standard_option);
 use PVE::ProcFSTools;
 use PVE::RADOS;
@@ -22,6 +23,16 @@ my $get_parent_image_name = sub {
     return $parent->{image} . "@" . $parent->{snapshot};
 };
 
+my $librados_connect = sub {
+    my ($scfg, $storeid, $options) = @_;
+
+    my $librados_config = PVE::CephConfig::ceph_connect_option($scfg, $storeid);
+
+    my $rados = PVE::RADOS->new(%$librados_config);
+
+    return $rados;
+};
+
 my sub get_rbd_path {
     my ($scfg, $volume) = @_;
     my $path = $scfg->{pool} ? $scfg->{pool} : 'rbd';
@@ -30,6 +41,32 @@ my sub get_rbd_path {
     return $path;
 };
 
+my sub get_rbd_dev_path {
+    my ($scfg, $storeid, $volume) = @_;
+
+    my $cluster_id = '';
+    if ($scfg->{monhost}) {
+	my $rados = $librados_connect->($scfg, $storeid);
+	$cluster_id = $rados->mon_command({ prefix => 'fsid', format => 'json' })->{fsid};
+    } else {
+	$cluster_id = cfs_read_file('ceph.conf')->{global}->{fsid};
+    }
+
+    my $uuid_pattern = "([0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12})";
+    if ($cluster_id =~ qr/^${uuid_pattern}$/is) {
+	$cluster_id = $1; # use untained value
+    } else {
+	die "cluster fsid has invalid format\n";
+    }
+
+    my $rbd_path = get_rbd_path($scfg, $volume);
+    my $pve_path = "/dev/rbd-pve/${cluster_id}/${rbd_path}";
+    my $path = "/dev/rbd/${rbd_path}";
+
+    return $path if -e $path && !-e $pve_path; # mapped before rbd-pve udev rule existed
+    return $pve_path;
+}
+
 my $build_cmd = sub {
     my ($binary, $scfg, $storeid, $op, @options) = @_;
 
@@ -70,16 +107,6 @@ my $rados_cmd = sub {
     return $build_cmd->('/usr/bin/rados', $scfg, $storeid, $op, @options);
 };
 
-my $librados_connect = sub {
-    my ($scfg, $storeid, $options) = @_;
-
-    my $librados_config = PVE::CephConfig::ceph_connect_option($scfg, $storeid);
-
-    my $rados = PVE::RADOS->new(%$librados_config);
-
-    return $rados;
-};
-
 # needed for volumes created using ceph jewel (or higher)
 my $krbd_feature_update = sub {
     my ($scfg, $storeid, $name) = @_;
@@ -380,9 +407,10 @@ sub path {
     my ($vtype, $name, $vmid) = $class->parse_volname($volname);
     $name .= '@'.$snapname if $snapname;
 
-    my $rbd_path = get_rbd_path($scfg, $name);
-    return ("/dev/rbd/${rbd_path}", $vmid, $vtype) if $scfg->{krbd};
+    my $rbd_dev_path = get_rbd_dev_path($scfg, $storeid, $name);
+    return ($rbd_dev_path, $vmid, $vtype) if $scfg->{krbd};
 
+    my $rbd_path = get_rbd_path($scfg, $name);
     my $path = "rbd:${rbd_path}";
 
     $path .= ":conf=$cmd_option->{ceph_conf}" if $cmd_option->{ceph_conf};
@@ -619,8 +647,8 @@ sub deactivate_storage {
 }
 
 my sub get_kernel_device_path {
-    my ($scfg, $name) = @_;
-    return "/dev/rbd/" . get_rbd_path($scfg, $name);
+    my ($scfg, $storeid, $name) = @_;
+    return get_rbd_dev_path($scfg, $storeid, $name);
 };
 
 sub map_volume {
@@ -631,7 +659,7 @@ sub map_volume {
     my $name = $img_name;
     $name .= '@'.$snapname if $snapname;
 
-    my $kerneldev = get_kernel_device_path($scfg, $name);
+    my $kerneldev = get_kernel_device_path($scfg, $storeid, $name);
 
     return $kerneldev if -b $kerneldev; # already mapped
 
@@ -650,7 +678,7 @@ sub unmap_volume {
     my ($vtype, $name, $vmid) = $class->parse_volname($volname);
     $name .= '@'.$snapname if $snapname;
 
-    my $kerneldev = get_kernel_device_path($scfg, $name);
+    my $kerneldev = get_kernel_device_path($scfg, $storeid, $name);
 
     if (-b $kerneldev) {
 	my $cmd = $rbd_cmd->($scfg, $storeid, 'unmap', $kerneldev);

udev-rbd/50-rbd-pve.rules

@@ -0,0 +1,2 @@
+KERNEL=="rbd[0-9]*", ENV{DEVTYPE}=="disk", PROGRAM="/usr/libexec/ceph-rbdnamer-pve %k", SYMLINK+="rbd-pve/%c"
+KERNEL=="rbd[0-9]*", ENV{DEVTYPE}=="partition", PROGRAM="/usr/libexec/ceph-rbdnamer-pve %k", SYMLINK+="rbd-pve/%c-part%n"

udev-rbd/Makefile

@@ -0,0 +1,21 @@
+PACKAGE=libpve-storage-perl
+
+DESTDIR=
+PREFIX=/usr
+LIBEXECDIR=${PREFIX}/libexec
+LIBDIR=${PREFIX}/lib
+
+all:
+
+.PHONY: install
+install: 50-rbd-pve.rules ceph-rbdnamer-pve
+	install -d ${DESTDIR}${LIBEXECDIR}
+	install -m 0755 ceph-rbdnamer-pve ${DESTDIR}${LIBEXECDIR}
+	install -d ${DESTDIR}${LIBDIR}/udev/rules.d
+	install -m 0644 50-rbd-pve.rules ${DESTDIR}${LIBDIR}/udev/rules.d
+
+.PHONY: clean
+clean:
+
+.PHONY: distclean
+distclean: clean

udev-rbd/ceph-rbdnamer-pve

@@ -0,0 +1,24 @@
+#!/bin/sh
+
+DEV=$1
+NUM=`echo $DEV | sed 's#p.*##g; s#[a-z]##g'`
+POOL=`cat /sys/devices/rbd/$NUM/pool`
+CLUSTER_FSID=`cat /sys/devices/rbd/$NUM/cluster_fsid`
+
+if [ -f /sys/devices/rbd/$NUM/pool_ns ]; then
+    NAMESPACE=`cat /sys/devices/rbd/$NUM/pool_ns`
+else
+    NAMESPACE=""
+fi
+IMAGE=`cat /sys/devices/rbd/$NUM/name`
+SNAP=`cat /sys/devices/rbd/$NUM/current_snap`
+
+echo -n "/$CLUSTER_FSID/$POOL"
+
+if [ -n "$NAMESPACE" ]; then
+    echo -n "/$NAMESPACE"
+fi
+echo -n "/$IMAGE"
+if [ "$SNAP" != "-" ]; then
+    echo -n "@$SNAP"
+fi