master - lv{resize, extend, reduce}: reject size change on 2-legged raid5*

[Heinz Mauelshagen <heinzm@sourceware.org>]

Gitweb:        https://sourceware.org/git/?p=lvm2.git;a=commitdiff;h=2cf0f90780bed64cb4062eb6dfa714ed03eecfb7
Commit:        2cf0f90780bed64cb4062eb6dfa714ed03eecfb7
Parent:        3bd9d81b29fb8ba490d87b3557861bf00047855d
Author:        Heinz Mauelshagen <heinzm@redhat.com>
AuthorDate:    Wed Jun 24 13:52:53 2020 +0200
Committer:     Heinz Mauelshagen <heinzm@redhat.com>
CommitterDate: Wed Jun 24 13:52:56 2020 +0200

lv{resize,extend,reduce}: reject size change on 2-legged raid5*

Reject size changing request in to avoid 'Bus error' and
display hint to convert to more stripes.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1784351
---
 lib/metadata/lv_manip.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/lib/metadata/lv_manip.c b/lib/metadata/lv_manip.c
index c1c86aa4c..142435bbb 100644
--- a/lib/metadata/lv_manip.c
+++ b/lib/metadata/lv_manip.c
@@ -5066,6 +5066,7 @@ static int _lvresize_check(struct logical_volume *lv,
 			   struct lvresize_params *lp)
 {
 	struct volume_group *vg = lv->vg;
+	struct lv_segment *seg = first_seg(lv);
 
 	if (lv_is_external_origin(lv)) {
 		/*
@@ -5089,6 +5090,12 @@ static int _lvresize_check(struct logical_volume *lv,
 		return 0;
 	}
 
+	if (seg && seg_is_any_raid5(seg) && seg->area_count < 3) {
+		log_error("Cannot resize %s LV %s. Convert to more stripes first.",
+			  lvseg_name(seg), display_lvname(lv));
+		return 0;
+	}
+
 	if (lv_is_raid(lv) &&
 	    lp->resize == LV_REDUCE) {
 		unsigned attrs;