master - lvreduce: check LV has segment

[Zdenek Kabelac]

Gitweb:        https://sourceware.org/git/?p=lvm2.git;a=commitdiff;h=83d5db056ba646ae69135b...
Commit:        83d5db056ba646ae69135b5f0114d1cc19b26044
Parent:        04244107732feb5274bc24efed428a0d4ddae8f6
Author:        Zdenek Kabelac 
AuthorDate:    Mon Oct 30 14:35:31 2017 +0100
Committer:     Zdenek Kabelac 
CommitterDate: Mon Oct 30 14:39:16 2017 +0100

lvreduce: check LV has segment

Before accessing content make sure LV has segment.
This can be used in case code removes LV without segments
(i.e. on some error path)
---
 lib/metadata/lv_manip.c |   16 ++++++++++++----
 1 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/lib/metadata/lv_manip.c b/lib/metadata/lv_manip.c
index 01ba564..a3634ac 100644
--- a/lib/metadata/lv_manip.c
+++ b/lib/metadata/lv_manip.c
@@ -1315,13 +1315,19 @@ static int _lv_segment_reduce(struct lv_segment *seg, uint32_t reduction)
  */
 static int _lv_reduce(struct logical_volume *lv, uint32_t extents, int delete)
 {
-	struct lv_segment *seg = first_seg(lv);;
+	struct lv_segment *seg = NULL;
    uint32_t count = extents;
    uint32_t reduction;
    struct logical_volume *pool_lv;
    struct logical_volume *external_lv = NULL;
-	int is_raid10 = seg_is_any_raid10(seg) && seg->reshape_len;
-	uint32_t data_copies = seg->data_copies;
+	int is_raid10 = 0;
+	uint32_t data_copies = 0;
+
+	if (!dm_list_empty(&lv->segments)) {
+		seg = first_seg(lv);
+		is_raid10 = seg_is_any_raid10(seg) && seg->reshape_len;
+		data_copies = seg->data_copies;
+	}

if (lv_is_merging_origin(lv)) {
    	log_debug_metadata("Dropping snapshot merge of %s to removed origin %s.",
@@ -7660,8 +7666,10 @@ static struct logical_volume *_lv_create_an_lv(struct volume_group *vg,
    	       lp->mirrors,
    	       segtype_is_pool(create_segtype) ? lp->pool_metadata_extents : lp->region_size,
    	       segtype_is_thin_volume(create_segtype) ? lp->virtual_extents : lp->extents,
-		       lp->pvh, lp->alloc, lp->approx_alloc))
+		       lp->pvh, lp->alloc, lp->approx_alloc)) {
+		unlink_lv_from_vg(lv); /* Keep VG consistent and remove LV without any segment */
    	return_NULL;
+	}

/* rhbz1269533: allow for 100%FREE allocation to work with "mirror" and a disk log */
    if (segtype_is_mirror(create_segtype) &&