From f82bddb76caef138b9a12d929ff610d8ca6d117a Mon Sep 17 00:00:00 2001 From: Zdenek Kabelac Date: Thu, 19 Jan 2012 15:39:41 +0000 Subject: [PATCH] Thin disable snapshot creation when pool is over the threshold. Since snapshot needs to suspend origin - it might lead to pool userspace deadlock (as the pool will wait for new space in case it would be overfilled, but dmeventd would not be able to resize it, as the lvcreate operation would have kept the VG lock.) To minimize the risk of such scenario - we prevent to create new snapshot in case we are over the threshold - but beware, there is still small timewindow, so keep threshold at some reasonable level! --- lib/metadata/lv_manip.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/lib/metadata/lv_manip.c b/lib/metadata/lv_manip.c index 47f60a661..f48919df6 100644 --- a/lib/metadata/lv_manip.c +++ b/lib/metadata/lv_manip.c @@ -3996,6 +3996,7 @@ static struct logical_volume *_lv_create_an_lv(struct volume_group *vg, struct l struct logical_volume *lv, *org = NULL; struct logical_volume *pool_lv; struct lv_list *lvl; + percent_t percent; int origin_active = 0; struct lvinfo info; @@ -4315,6 +4316,14 @@ static struct logical_volume *_lv_create_an_lv(struct volume_group *vg, struct l if (seg_is_thin(lp)) { /* For thin snapshot suspend active thin origin first */ if (org && lv_is_active(org)) { + lv_thin_pool_percent(first_seg(org)->pool_lv, 0, &percent); + percent /= PERCENT_1; + if (percent >= (find_config_tree_int(cmd, "activation/thin_pool_autoextend_threshold", + DEFAULT_THIN_POOL_AUTOEXTEND_THRESHOLD))) { + log_error("Failed to create snapshot, pool is filled over " + "the autoextend threshold (%d%%).", percent); + goto revert_new_lv; + } if (!suspend_lv(cmd, org)) { log_error("Failed to suspend thin origin %s.", org->name);