From 16ab7a0da2a6a503644a985bc9e25686ce7324d5 Mon Sep 17 00:00:00 2001
From: Joe Thornber <thornber@redhat.com>
Date: Mon, 7 Jan 2002 15:08:28 +0000
Subject: [PATCH] o  New function 'merge_segments'

o  Call said function at end of lv_extend
---
 lib/Makefile.in         |  1 +
 lib/metadata/lv_manip.c |  9 ++++++-
 lib/metadata/merge.c    | 55 +++++++++++++++++++++++++++++++++++++++++
 lib/metadata/merge.h    | 20 +++++++++++++++
 4 files changed, 84 insertions(+), 1 deletion(-)
 create mode 100644 lib/metadata/merge.c
 create mode 100644 lib/metadata/merge.h

diff --git a/lib/Makefile.in b/lib/Makefile.in
index ebac6e57c..c6aa882f5 100644
--- a/lib/Makefile.in
+++ b/lib/Makefile.in
@@ -37,6 +37,7 @@ SOURCES=\
 	label/label.c \
 	log/log.c \
 	metadata/lv_manip.c \
+	metadata/merge.c \
 	metadata/metadata.c \
 	metadata/pv_map.c \
 	mm/dbg_malloc.c \
diff --git a/lib/metadata/lv_manip.c b/lib/metadata/lv_manip.c
index 7de92ed81..8dbc72fd2 100644
--- a/lib/metadata/lv_manip.c
+++ b/lib/metadata/lv_manip.c
@@ -9,6 +9,7 @@
 #include "log.h"
 #include "dbg_malloc.h"
 #include "lvm-string.h"
+#include "merge.h"
 
 #include <assert.h>
 
@@ -150,7 +151,7 @@ static int _alloc_striped(struct logical_volume *lv,
 		/* sort the areas so we allocate from the biggest */
 		qsort(areas, index, sizeof(*areas), _comp_area);
 
-		if (!_alloc_stripe_area(lv, stripes, stripe_size, areas, 
+		if (!_alloc_stripe_area(lv, stripes, stripe_size, areas,
 					&allocated)) {
 			stack;
 			goto out;
@@ -497,6 +498,12 @@ int lv_extend(struct logical_volume *lv,
 		return 0;
 	}
 
+	if (!merge_segments(lv)) {
+		log_err("Couldn't merge segments after extending "
+			"logical volume.");
+		return 0;
+	}
+
 	return 1;
 }
 
diff --git a/lib/metadata/merge.c b/lib/metadata/merge.c
new file mode 100644
index 000000000..9c390944c
--- /dev/null
+++ b/lib/metadata/merge.c
@@ -0,0 +1,55 @@
+/*
+ * Copyright (C) 2001 Sistina Software
+ *
+ * This file is released under the LGPL.
+ */
+
+#include "log.h"
+#include "merge.h"
+
+/*
+ * Returns success if the segments were
+ * successfully merged.  If the do merge, 'first'
+ * will be adjusted to contain both areas.
+ */
+static int _merge(struct stripe_segment *first, struct stripe_segment *second)
+{
+	int s;
+	uint32_t width;
+
+	if (!first ||
+	    (first->stripes != second->stripes) ||
+	    (first->stripe_size != second->stripe_size))
+		return 0;
+
+	for (s = 0; s < first->stripes; s++) {
+		width = first->len / first->stripes;
+
+		if ((first->area[s].pv != second->area[s].pv) ||
+		    (first->area[s].pe + width != second->area[s].pe))
+			return 0;
+	}
+
+	/* we should merge */
+	first->len += second->len;
+
+	return 1;
+}
+
+int merge_segments(struct logical_volume *lv)
+{
+	struct list *segh;
+	struct stripe_segment *current, *prev = NULL;
+
+	list_iterate (segh, &lv->segments) {
+		current = list_item(segh, struct stripe_segment);
+
+		if (_merge(prev, current))
+			list_del(&current->list);
+		else
+			prev = current;
+	}
+
+	return 1;
+}
+
diff --git a/lib/metadata/merge.h b/lib/metadata/merge.h
new file mode 100644
index 000000000..f15b2376a
--- /dev/null
+++ b/lib/metadata/merge.h
@@ -0,0 +1,20 @@
+/*
+ * Copyright (C) 2001 Sistina Software
+ *
+ * This file is released under the LGPL.
+ */
+
+#ifndef _LVM_MERGE_H
+#define _LVM_MERGE_H
+
+#include "metadata.h"
+
+/*
+ * Sometimes (eg, after an lvextend), it is
+ * possible to merge two adjacent segments into a
+ * single segment.  This function trys to merge as
+ * many segments as possible.
+ */
+int merge_segments(struct logical_volume *lv);
+
+#endif /* _LVM_MERGE_H */