From 07a25c249b3ed449ca9f678c19ddb320967adaa9 Mon Sep 17 00:00:00 2001
From: Alasdair G Kergon <agk@redhat.com>
Date: Wed, 27 Jun 2012 21:53:02 +0100
Subject: discards: don't discard reconfigured extents

Update release_lv_segment_area not to discard any PV extents,
as it also gets used when moving extents between LVs.
Instead, call a new function release_and_discard_lv_segment_area() in
the two places where data should be discarded - lv_reduce() and
remove_mirrors_from_segments().
---
 lib/metadata/lv_alloc.h |  1 +
 lib/metadata/lv_manip.c | 21 ++++++++++++++++++---
 lib/metadata/mirror.c   |  2 +-
 3 files changed, 20 insertions(+), 4 deletions(-)

(limited to 'lib')

diff --git a/lib/metadata/lv_alloc.h b/lib/metadata/lv_alloc.h
index 71ca1abd..9f8e0e3a 100644
--- a/lib/metadata/lv_alloc.h
+++ b/lib/metadata/lv_alloc.h
@@ -42,6 +42,7 @@ int move_lv_segment_area(struct lv_segment *seg_to, uint32_t area_to,
 			 struct lv_segment *seg_from, uint32_t area_from);
 int release_lv_segment_area(struct lv_segment *seg, uint32_t s,
 			    uint32_t area_reduction);
+int release_and_discard_lv_segment_area(struct lv_segment *seg, uint32_t s, uint32_t area_reduction);
 
 struct alloc_handle;
 struct alloc_handle *allocate_extents(struct volume_group *vg,
diff --git a/lib/metadata/lv_manip.c b/lib/metadata/lv_manip.c
index bdcc925b..a0be8875 100644
--- a/lib/metadata/lv_manip.c
+++ b/lib/metadata/lv_manip.c
@@ -299,17 +299,22 @@ struct lv_segment *alloc_snapshot_seg(struct logical_volume *lv,
 	return seg;
 }
 
-int release_lv_segment_area(struct lv_segment *seg, uint32_t s,
-			    uint32_t area_reduction)
+static int _release_and_discard_lv_segment_area(struct lv_segment *seg, uint32_t s,
+						uint32_t area_reduction, int with_discard)
 {
 	if (seg_type(seg, s) == AREA_UNASSIGNED)
 		return 1;
 
 	if (seg_type(seg, s) == AREA_PV) {
+		if (with_discard && !discard_pv_segment(seg_pvseg(seg, s), area_reduction))
+			return_0;
+
 		if (!release_pv_segment(seg_pvseg(seg, s), area_reduction))
 			return_0;
+
 		if (seg->area_len == area_reduction)
 			seg_type(seg, s) = AREA_UNASSIGNED;
+
 		return 1;
 	}
 
@@ -365,6 +370,16 @@ int release_lv_segment_area(struct lv_segment *seg, uint32_t s,
 	return 1;
 }
 
+int release_and_discard_lv_segment_area(struct lv_segment *seg, uint32_t s, uint32_t area_reduction)
+{
+	return _release_and_discard_lv_segment_area(seg, s, area_reduction, 1);
+}
+
+int release_lv_segment_area(struct lv_segment *seg, uint32_t s, uint32_t area_reduction)
+{
+	return _release_and_discard_lv_segment_area(seg, s, area_reduction, 0);
+}
+
 /*
  * Move a segment area from one segment to another
  */
@@ -501,7 +516,7 @@ static int _lv_segment_reduce(struct lv_segment *seg, uint32_t reduction)
 		area_reduction = reduction;
 
 	for (s = 0; s < seg->area_count; s++)
-		if (!release_lv_segment_area(seg, s, area_reduction))
+		if (!release_and_discard_lv_segment_area(seg, s, area_reduction))
 			return_0;
 
 	seg->len -= reduction;
diff --git a/lib/metadata/mirror.c b/lib/metadata/mirror.c
index d943175e..61e4b471 100644
--- a/lib/metadata/mirror.c
+++ b/lib/metadata/mirror.c
@@ -1469,7 +1469,7 @@ int remove_mirrors_from_segments(struct logical_volume *lv,
 		}
 
 		for (s = new_mirrors + 1; s < seg->area_count; s++)
-			if (!release_lv_segment_area(seg, s, seg->area_len))
+			if (!release_and_discard_lv_segment_area(seg, s, seg->area_len))
 				return_0;
 
 		seg->area_count = new_mirrors + 1;
-- 
cgit