Warn of deadlock risk when using snapshots of mirror segment type.

diff --git a/WHATS_NEW b/WHATS_NEW
index ca16522c0ed5c57e8b75b74699e61d0299391175..03cb07dd7b30ad0fcac334a8e9a8a094afd13db0 100644 (file)
--- a/WHATS_NEW
+++ b/WHATS_NEW
@@ -9,7 +9,7 @@ Version 2.02.96 -
   Add initial support for thin pool lvconvert.
   Fix lvrename for thin volumes (regression in for_each_sub_lv() 2.02.89).
   Fix up-convert when mirror activation is controled by volume_list and tags.
-  Disallow snapshots of mirror segment type.
+  Warn of deadlock risk when using snapshots of mirror segment type.
   Fix bug in cmirror that caused incorrect status info to print on some nodes.
   Remove statement that snapshots cannot be tagged from lvm man page.
   Disallow changing cluster attribute of VG while RAID LVs are active.

diff --git a/lib/metadata/lv_manip.c b/lib/metadata/lv_manip.c
index 15a1945aa27b1685a13b916e89833082fe5ed109..3913680cc6708e4bad0de7fb7671f9dcb0023a82 100644 (file)
--- a/lib/metadata/lv_manip.c
+++ b/lib/metadata/lv_manip.c
@@ -4231,9 +4231,9 @@ static struct logical_volume *_lv_create_an_lv(struct volume_group *vg, struct l
 
                        if (lv_is_mirror_type(org) &&
                            !seg_is_raid(first_seg(org))) {
-                               log_error("Snapshots of \"mirror\" segment types"
-                                         " are not supported");
-                               return NULL;
+                               log_warn("WARNING: Snapshots of mirrors can deadlock under rare device failures.");
+                               log_warn("WARNING: Consider using the raid1 mirror type to avoid this.");
+                               log_warn("WARNING: See global/mirror_segtype_default in lvm.conf.");
                        }
 
                        if (!lv_info(cmd, org, 0, &info, 0, 0)) {