Gitweb: http://git.fedorahosted.org/git/?p=lvm2.git;a=commitdiff;h=d455300d7baff341f... Commit: d455300d7baff341f1c7fe5776d975369dd3a23a Parent: 629059ee84e83b9d013d80e0b382a3474b30c7a4 Author: David Teigland teigland@redhat.com AuthorDate: Tue Sep 13 16:50:47 2016 -0500 Committer: David Teigland teigland@redhat.com CommitterDate: Wed Sep 14 10:43:33 2016 -0500

lvmlockd: fix metadata validation when rescanning VG

When rescanning a VG from disk, the metadata read from each PV was compared as a sanity check. The comparison is done by exporting the vg metadata from each dev to a config tree, and then comparing the config trees. The function to create the config tree inserts extraneous information along with the actual VG metadata. This extra info includes creation_time. The config trees for two devs can easily be created one second apart in which case the different creation_times would cause the metadata comparison to fail. The fix is to exclude the extraneous info from the metadata comparison. --- lib/cache/lvmetad.c | 31 ++++++++++++++++++++++++++++++- 1 files changed, 30 insertions(+), 1 deletions(-)

diff --git a/lib/cache/lvmetad.c b/lib/cache/lvmetad.c index b3cd1bf..727d3d3 100644 --- a/lib/cache/lvmetad.c +++ b/lib/cache/lvmetad.c @@ -1918,15 +1918,44 @@ scan_more: vgmeta_ret = vgmeta; save_dev = devl->dev; } else { - if (compare_config(vgmeta_ret->root, vgmeta->root)) { + struct dm_config_node *meta1 = vgmeta_ret->root; + struct dm_config_node *meta2 = vgmeta->root; + struct dm_config_node *sib1 = meta1->sib; + struct dm_config_node *sib2 = meta2->sib; + + /* + * Do not compare the extraneous data that + * export_vg_to_config_tree() inserts next to the + * actual VG metadata. This includes creation_time + * which may not match since it is generated separately + * for each call to create the config tree. + * + * We're saving the sibling pointer and restoring it + * after the compare because we're unsure if anything + * later might want it. + * + * FIXME: make it clearer what we're doing here, e.g. + * pass a parameter to export_vg_to_config_tree() + * telling it to skip the extraneous data, or something. + * It's very non-obvious that setting sib=NULL does that. + */ + meta1->sib = NULL; + meta2->sib = NULL; + + if (compare_config(meta1, meta2)) { log_error("VG %s metadata comparison failed for device %s vs %s", vg->name, dev_name(devl->dev), save_dev ? dev_name(save_dev) : "none"); _log_debug_inequality(vg->name, vgmeta_ret->root, vgmeta->root); + + meta1->sib = sib1; + meta2->sib = sib2; dm_config_destroy(vgmeta); dm_config_destroy(vgmeta_ret); release_vg(baton.vg); return NULL; } + meta1->sib = sib1; + meta2->sib = sib2; dm_config_destroy(vgmeta); }