Add linux_lvm_mountargs option

In order to allow backups of Linux LVM logical volumes containing
a mix of xfs and non-xfs filesystems, it is necessary to have the
ability to pass options to the mount command.  This commit adds
a linux_lvm_mountargs config variable.

rsnapshot-program.pl

@@ -1411,7 +1411,7 @@ sub parse_config_file {
 		}
 
 		# LVM ARGS
-		if ($var =~ m/^linux_lvm_(vgpath|snapshotname|snapshotsize|mountpath)$/) {
+		if ($var =~ m/^linux_lvm_(vgpath|snapshotname|snapshotsize|mountpath|mountargs)$/) {
 			$config_vars{$var} = $value;
 			$line_syntax_ok = 1;
 			next;
@@ -1835,7 +1835,7 @@ sub parse_backup_opts {
 
 			# lvm args
 		}
-		elsif ($name =~ m/^linux_lvm_(vgpath|snapshotname|snapshotsize|mountpath)$/) {
+		elsif ($name =~ m/^linux_lvm_(vgpath|snapshotname|snapshotsize|mountpath|mountargs)$/) {
 
 			# pass unchecked
 
@@ -3775,7 +3775,12 @@ sub rsync_backup_point {
 		$lvm_opts{'snapshotname'} = $config_vars{'linux_lvm_snapshotname'};
 		$lvm_opts{'vgpath'} = $config_vars{'linux_lvm_vgpath'};
 		$lvm_opts{'mountpath'} = $config_vars{'linux_lvm_mountpath'};
+		# Mount args are optional.
+		if (defined($config_vars{'linux_lvm_mountargs'})) {
+			$lvm_opts{'mountargs'} = $config_vars{'linux_lvm_mountargs'};
+		}
 
+		# Allow backup point option to override config variable value.
 		if (defined($$bp_ref{'opts'})) {
 			if (defined($$bp_ref{'opts'}->{'linux_lvm_snapshotsize'})) {
 				$lvm_opts{'snapshotsize'} = $$bp_ref{'opts'}->{'linux_lvm_snapshotsize'};
@@ -3789,6 +3794,9 @@ sub rsync_backup_point {
 			if (defined($$bp_ref{'opts'}->{'linux_lvm_mountpath'})) {
 				$lvm_opts{'mountpath'} = $$bp_ref{'opts'}->{'linux_lvm_mountpath'};
 			}
+			if (defined($$bp_ref{'opts'}->{'linux_lvm_mountargs'})) {
+				$lvm_opts{'mountargs'} = $$bp_ref{'opts'}->{'linux_lvm_mountargs'};
+			}
 		}
 
 		$lvm_src = $src;
@@ -4093,6 +4101,10 @@ sub linux_lvm_mount {
 	my @cmd_stack = ();
 	push(@cmd_stack, split(' ', $config_vars{'linux_lvm_cmd_mount'}));
 
+	if (defined($$opts_ref{'mountargs'})) {
+		push(@cmd_stack, split(' ', $$opts_ref{'mountargs'}));
+	}
+
 	push(
 		@cmd_stack,
 		join('/',
@@ -7095,6 +7107,44 @@ =head1 CONFIGURATION
 
 =back
 
+B<linux_lvm_mountargs		[args]>
+
+=over 4
+
+Arguments to be used when temporarily mounting the LVM snapshot(s).  This
+can be used supply any special mount options that may be needed.  For
+example, when mounting a snapshot of an xfs filesystem, it is necessary
+to use the nouuid mount option.
+
+=over 4
+
+Example:
+
+B<linux_lvm_mountargs   -o nouuid>
+
+=back
+
+This allows snapshots of xfs filesystems to be properly mounted.  If LVM
+snapshots are being used with a mix of xfs and non-xfs filesystems, the
+linux_lvm_mountargs option can be set on a per-backup-point basis.  The
+backup point option will override the config value.
+
+It is also common to mount the snapshot readonly.  This can be done by
+specifying the readonly argument when defining linux_lvm_cmd_mount, or by
+specifying it in linux_lvm_mountargs.
+
+=over 4
+
+Example:
+
+B<linux_lvm_mountargs   -o ro,nouuid>
+
+=back
+
+This supplies the proper arguments to mount an xfs snapshot in readonly mode.
+
+=back
+
 B<backup>  /etc/                       localhost/
 
 B<backup>  root@example.com:/etc/      example.com/
@@ -7105,6 +7155,8 @@ =head1 CONFIGURATION
 
 B<backup>  lvm://vg0/home/path2/       lvm-vg0/
 
+B<backup>  lvm://vg0/home/path2/       lvm-vg0/  linux_lvm_mountargs="-o ro,nouuid"
+
 B<backup_script>   /usr/local/bin/backup_pgsql.sh    pgsql_backup/
 
 =over 4
@@ -7199,6 +7251,17 @@ =head1 CONFIGURATION
 =back
 
 
+B<backup>  lvm://vg0/home/path2/       lvm-vg0/  linux_lvm_mountargs="-o ro,nouuid"
+
+=over 4
+
+Backs up the LVM logical volume as in the previous example, but when the
+LVM snapshot is mounted, "-o ro,nouuid" will be used as an argument to the
+mount command.
+
+=back
+
+
 B<backup_script      /usr/local/bin/backup_database.sh   db_backup/>
 
 =over 4

rsnapshot.conf.default.in

@@ -77,11 +77,13 @@ snapshot_root	/.snapshots/
 #cmd_postexec	/path/to/postexec/script
 
 # Paths to lvcreate, lvremove, mount and umount commands, for use with
-# Linux LVMs.
+# Linux LVMs.  If necessary, you can add arguments to any of the commands.
+# The example -r argument shown on the mount command will cause all
+# LVM snapshot mounts to be readonly.
 #
 #linux_lvm_cmd_lvcreate	@CMD_LVCREATE@
 #linux_lvm_cmd_lvremove	@CMD_LVREMOVE@
-#linux_lvm_cmd_mount	@CMD_MOUNT@
+#linux_lvm_cmd_mount	@CMD_MOUNT@ -r
 #linux_lvm_cmd_umount	@CMD_UMOUNT@
 
 #########################################
@@ -218,6 +220,11 @@ lockfile	/var/run/rsnapshot.pid
 #
 #linux_lvm_mountpath	/path/to/mount/lvm/snapshot/during/backup
 
+# Arguments to the mount command used to temporarily mount the snapshot(s).
+# You may need to define this when you use xfs filesystems.
+#
+#linux_lvm_mountargs	-o nouuid
+
 ###############################
 ### BACKUP POINTS / SCRIPTS ###
 ###############################
@@ -233,6 +240,9 @@ backup	/usr/local/	localhost/
 #backup_script	/usr/local/bin/backup_pgsql.sh	localhost/postgres/
 # You must set linux_lvm_* parameters below before using lvm snapshots
 #backup	lvm://vg0/xen-home/	lvm-vg0/xen-home/
+# You can override LVM options as needed.  Use quotes if your option needs to
+# contain a comma.
+#backup	lvm://vg0/xen-home/	lvm-vg0/xen-home/	linux_lvm_mountargs="-o ro,nouuid",linux_lvm_snapshotsize=1G
 
 # EXAMPLE.COM
 #backup_exec	/bin/date "+ backup of example.com started at %c"