lvm2: fix segfault for snapshot

Backport <commit c46d4a745dc8c5cb4cfc0c94863e555387e9af75> from lvm2
upstream <https://git.fedorahosted.org/git/lvm2.git> to solve issue:
vgchange segfault in lv_is_merging_cow function.

Signed-off-by: Li Zhou <li.zhou@windriver.com>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>

2 files changed, 31 insertions, 1 deletions

diff --git a/meta-oe/recipes-support/lvm2/lvm2.inc b/meta-oe/recipes-support/lvm2/lvm2.inc
index 42f6e3a43..e116629f8 100644
--- a/meta-oe/recipes-support/lvm2/lvm2.inc
+++ b/meta-oe/recipes-support/lvm2/lvm2.inc
@@ -11,7 +11,8 @@ S = "${WORKDIR}/LVM2.${PV}"
 SRC_URI = "ftp://sources.redhat.com/pub/lvm2/old/LVM2.${PV}.tgz \
            file://0001-Replace-CPPFunction-with-rl_completion_func_t.patch \
            file://mlock-ignore-vectors-gate_vma.patch \
-           file://lvm.conf"
+           file://lvm.conf \
+           file://0001-snapshot-check-snapshot-exists.patch"
 
 PACKAGECONFIG ??= "readline"
 PACKAGECONFIG[readline] = "--enable-readline,--disable-readline,readline"
diff --git a/meta-oe/recipes-support/lvm2/lvm2/0001-snapshot-check-snapshot-exists.patch b/meta-oe/recipes-support/lvm2/lvm2/0001-snapshot-check-snapshot-exists.patch
new file mode 100644
index 000000000..8f0da796d
--- /dev/null
+++ b/meta-oe/recipes-support/lvm2/lvm2/0001-snapshot-check-snapshot-exists.patch
@@ -0,0 +1,29 @@
+From c46d4a745dc8c5cb4cfc0c94863e555387e9af75 Mon Sep 17 00:00:00 2001
+From: Zdenek Kabelac <zkabelac@redhat.com>
+Date: Mon, 16 Jun 2014 12:41:30 +0200
+Subject: [PATCH] snapshot: check snapshot exists
+
+Return 0 if the LV is not even snapshot.
+
+Upstream-Status: backport
+Adapt the patch for backporting to an older version.
+Signed-off-by: Li Zhou <li.zhou@windriver.com>
+---
+ lib/metadata/snapshot_manip.c |    3 ++-
+ 1 file changed, 2 insertions(+), 1 deletion(-)
+
+Index: LVM2.2.02.97/lib/metadata/snapshot_manip.c
+===================================================================
+--- LVM2.2.02.97.orig/lib/metadata/snapshot_manip.c
++++ LVM2.2.02.97/lib/metadata/snapshot_manip.c
+@@ -68,8 +68,9 @@ struct lv_segment *find_merging_cow(cons
+
+ int lv_is_merging_cow(const struct logical_volume *snapshot)
+ {
++       struct lv_segment *snap_seg = find_cow(snapshot);
+        /* checks lv_segment's status to see if cow is merging */
+-       return (find_cow(snapshot)->status & MERGING) ? 1 : 0;
++       return (snap_seg && (snap_seg->status & MERGING)) ? 1 : 0;
+ }
+
+ /* Given a cow LV, return the snapshot lv_segment that uses it */