From a3c8fbc6b6b4c7ba1a3f988614fcdd9a2fb408a1 Mon Sep 17 00:00:00 2001
From: Milan Broz <mbroz@redhat.com>
Date: Wed, 9 Dec 2009 19:29:04 +0000
Subject: [PATCH] Allow manipulation with precommited metadata even when a PV
 is missing.

The new recovery code first tries to repair LV and then removes failed PV
from VG. It means that during operation there can be VG with PV missing,
and vg_read code handles it like not consistent VG.

We already allows returning "inconsistent" commited metadata,
for mirror repair we need this for precommited too.
(The suspend call prepares precommited metadata to inactive table on
other cluster nodes.)

"Inconsistent" here means - correct metadata, just with some metadata areas
not found (obviously on missing or failed PVs).
---
 WHATS_NEW               |  1 +
 lib/metadata/metadata.c | 13 +++++++++++++
 2 files changed, 14 insertions(+)

diff --git a/WHATS_NEW b/WHATS_NEW
index e39a67c75..f204c15a5 100644
--- a/WHATS_NEW
+++ b/WHATS_NEW
@@ -1,5 +1,6 @@
 Version 2.02.57 -
 ====================================
+  Allow use precommited metadata when a PV is missing.
   Add memlock information to do_lock_lv debug output.
   Never use distributed lock for LV in non-clustered VG.
   Allow implicit lock conversion in pre/post callbacks on local node.
diff --git a/lib/metadata/metadata.c b/lib/metadata/metadata.c
index 9d5b1ae03..8e3129ac9 100644
--- a/lib/metadata/metadata.c
+++ b/lib/metadata/metadata.c
@@ -2481,6 +2481,7 @@ static struct volume_group *_vg_read(struct cmd_context *cmd,
 	int inconsistent = 0;
 	int inconsistent_vgid = 0;
 	int inconsistent_pvs = 0;
+	int inconsistent_seqno = 0;
 	unsigned use_precommitted = precommitted;
 	unsigned saved_handles_missing_pvs = cmd->handles_missing_pvs;
 	struct dm_list *pvids;
@@ -2556,6 +2557,7 @@ static struct volume_group *_vg_read(struct cmd_context *cmd,
 		/* FIXME Also ensure contents same - checksum compare? */
 		if (correct_vg->seqno != vg->seqno) {
 			inconsistent = 1;
+			inconsistent_seqno = 1;
 			if (vg->seqno > correct_vg->seqno) {
 				vg_release(correct_vg);
 				correct_vg = vg;
@@ -2679,6 +2681,7 @@ static struct volume_group *_vg_read(struct cmd_context *cmd,
 			/* FIXME Also ensure contents same - checksums same? */
 			if (correct_vg->seqno != vg->seqno) {
 				inconsistent = 1;
+				inconsistent_seqno = 1;
 				if (!_update_pv_list(cmd->mem, &all_pvs, vg)) {
 					vg_release(vg);
 					vg_release(correct_vg);
@@ -2706,6 +2709,16 @@ static struct volume_group *_vg_read(struct cmd_context *cmd,
 		if (use_precommitted) {
 			log_error("Inconsistent pre-commit metadata copies "
 				  "for volume group %s", vgname);
+			/* FIXME: during repair, there is inconsistent flag set because some metadata areas
+			 * are missing (on missing PVs). Code should create list of missing PVs, compare it
+			 * with PV marked missing in metadata and if equals, use it as consistent vg.
+			 * For now, return precommited metadata if remainng seq match here to allow
+			 * preloading table in suspend call.
+			 */
+			if (!inconsistent_seqno) {
+				*consistent = 0;
+				return correct_vg;
+			}
 			vg_release(correct_vg);
 			return NULL;
 		}