vgextend: Allow PVs to be added to VGs that have PVs missing

Allowing people to add devices to a VG that has PVs missing helps
people avoid the inability to repair RAID LVs in certain cases.
For example, if a user creates a RAID 4/5/6 LV using all of the
available devices in a VG, there will be no spare devices to
repair the LV with if a device should fail.  Further, because the
VG is missing a device, new devices cannot be added to allow the
repair.  If 'vgreduce --removemissing' were attempted, the
"MISSING" PV could not be removed without also destroying the RAID
LV.

Allowing vgextend to operate solves the circular dependency.

When the PV is added by a vgextend operation, the sequence number is
incremented and the 'MISSING' flag is put on the PVs which are missing.

2 files changed, 8 insertions, 2 deletions

diff --git a/WHATS_NEW b/WHATS_NEW
index 735bdba4..32ebf15d 100644
--- a/WHATS_NEW
+++ b/WHATS_NEW
@@ -1,5 +1,6 @@
 Version 2.02.97 - 
 ===============================
+  Allow vgextend to add PVs to a VG that is missing PVs.
   Recognise Micron PCIe SSDs in filter and move array out to device-types.h.
   Fix segfault when attempting to replace RAID 4/5/6 device (2.02.97).
   Fix dumpconfig <node> to print only <node> without its siblings (2.02.89).
diff --git a/tools/vgextend.c b/tools/vgextend.c
index d1adf210..161796ce 100644
--- a/tools/vgextend.c
+++ b/tools/vgextend.c
@@ -66,8 +66,13 @@ int vgextend(struct cmd_context *cmd, int argc, char **argv)
 		return EINVALID_CMD_LINE;
 	}
 
-	if (arg_count(cmd, restoremissing_ARG))
-		cmd->handles_missing_pvs = 1;
+	/*
+	 * It is always ok to add new PVs to a VG - even if there are
+	 * missing PVs.  No LVs are affected by this operation, but
+	 * repair processes - particularly for RAID segtypes - can
+	 * be facilitated.
+	 */
+	cmd->handles_missing_pvs = 1;
 
 	log_verbose("Checking for volume group \"%s\"", vg_name);
 	vg = vg_read_for_update(cmd, vg_name, NULL, 0);