[lvm-devel] [PATCH 25/38] Make vg->mda_copies persistent in on disk vg metadata.

[Dave Wysochanski]

This patch adds the ability to read/write the vg->mda_copies values
from/to the vg metadata.

If we read the VG metadata and this field does not exist, we set
mda_copies to the default value of 0.  Later in the code, we use
this special '0' value to indicate a disable of metadata balancing.
This should preserve existing LVM behavior and ensure metadata balancing
can be turned off should the need arise.

Signed-off-by: Dave Wysochanski <dwysocha at redhat.com>
---
 lib/format_text/export.c      |    1 +
 lib/format_text/import_vsn1.c |    5 +++++
 2 files changed, 6 insertions(+), 0 deletions(-)

diff --git a/lib/format_text/export.c b/lib/format_text/export.c
index 5f02b5d..52ae11c 100644
--- a/lib/format_text/export.c
+++ b/lib/format_text/export.c
@@ -397,6 +397,7 @@ static int _print_vg(struct formatter *f, struct volume_group *vg)
 		outf(f, "allocation_policy = \"%s\"",
 		     get_alloc_string(vg->alloc));
 	}
+	outf(f, "metadata_copies = %u", vg->mda_copies);
 
 	return 1;
 }
diff --git a/lib/format_text/import_vsn1.c b/lib/format_text/import_vsn1.c
index 316adb5..62bcbec 100644
--- a/lib/format_text/import_vsn1.c
+++ b/lib/format_text/import_vsn1.c
@@ -23,6 +23,7 @@
 #include "pv_alloc.h"
 #include "segtype.h"
 #include "text_import.h"
+#include "defaults.h"
 
 typedef int (*section_fn) (struct format_instance * fid, struct dm_pool * mem,
 			   struct volume_group * vg, struct config_node * pvn,
@@ -745,6 +746,10 @@ static struct volume_group *_read_vg(struct format_instance *fid,
 			return_0;
 	}
 
+	if (!_read_uint32(vgn, "metadata_copies", &vg->mda_copies)) {
+		vg->mda_copies = DEFAULT_VGMETADATACOPIES;
+	}
+
 	/*
 	 * The pv hash memorises the pv section names -> pv
 	 * structures.
-- 
1.6.0.6