label_scan: fix label scan for independent metadata areas

When label_scan reads metadata from independent areas, not
from the devices, set a flag on the vginfo.  Use this flag
to avoid trying to rescan those devices in vg_read() since
the metadata won't be found on them, and wreck the lvmcache
data set up by the label scan.

3 files changed, 42 insertions, 4 deletions

diff --git a/lib/cache/lvmcache.c b/lib/cache/lvmcache.c
index 7846ce461..4fe0dc070 100644
--- a/lib/cache/lvmcache.c
+++ b/lib/cache/lvmcache.c
@@ -63,6 +63,7 @@ struct lvmcache_vginfo {
 	char *lock_type;
 	uint32_t mda_checksum;
 	size_t mda_size;
+	int independent_metadata_location; /* metadata read from independent areas */
 	/*
 	 * The following are not related to lvmcache or vginfo,
 	 * but are borrowing the vginfo to store the data.
@@ -1169,6 +1170,16 @@ int lvmcache_label_rescan_vg(struct cmd_context *cmd, const char *vgname, const
 	if (!(vginfo = lvmcache_vginfo_from_vgname(vgname, vgid)))
 		return_0;
 
+	/*
+	 * When the VG metadata is from an independent location,
+	 * then rescanning the devices in the VG won't find the
+	 * metadata, and will destroy the vginfo/info associations
+	 * that were created during label scan when the
+	 * independent locations were read.
+	 */
+	if (vginfo->independent_metadata_location)
+		return 1;
+
 	dm_list_iterate_items(info, &vginfo->infos) {
 		if (!(devl = dm_malloc(sizeof(*devl)))) {
 			log_error("device_list element allocation failed");
@@ -2620,6 +2631,14 @@ int lvmcache_vgid_is_cached(const char *vgid) {
 	return 1;
 }
 
+void lvmcache_set_independent_location(const char *vgname)
+{
+	struct lvmcache_vginfo *vginfo;
+
+	if ((vginfo = lvmcache_vginfo_from_vgname(vgname, NULL)))
+		vginfo->independent_metadata_location = 1;
+}
+
 /*
  * Return true iff it is impossible to find out from this info alone whether the
  * PV in question is or is not an orphan.
diff --git a/lib/cache/lvmcache.h b/lib/cache/lvmcache.h
index 19bafc2e2..e36284c24 100644
--- a/lib/cache/lvmcache.h
+++ b/lib/cache/lvmcache.h
@@ -219,4 +219,5 @@ int lvmcache_get_vg_devs(struct cmd_context *cmd,
                          struct lvmcache_vginfo *vginfo,
                          struct dm_list *devs);
 
+void lvmcache_set_independent_location(const char *vgname);
 #endif
diff --git a/lib/format_text/format-text.c b/lib/format_text/format-text.c
index 8bf0fca77..072c769e4 100644
--- a/lib/format_text/format-text.c
+++ b/lib/format_text/format-text.c
@@ -911,8 +911,10 @@ static struct volume_group *_vg_read_file_name(struct format_instance *fid,
 	time_t when;
 	char *desc;
 
-	if (!(vg = text_read_metadata_file(fid, read_path, &when, &desc)))
-		return_NULL;
+	if (!(vg = text_read_metadata_file(fid, read_path, &when, &desc))) {
+		log_error("Failed to read VG %s from %s", vgname, read_path);
+		return NULL;
+	}
 
 	/*
 	 * Currently you can only have a single volume group per
@@ -1138,6 +1140,9 @@ static int _scan_file(const struct format_type *fmt, const char *vgname)
 
 	dir_list = &((struct mda_lists *) fmt->private)->dirs;
 
+	if (!dm_list_empty(dir_list))
+		log_debug_metadata("Scanning independent files for %s", vgname ? vgname : "VGs");
+
 	dm_list_iterate_items(dl, dir_list) {
 		if (!(d = opendir(dl->dir))) {
 			log_sys_error("opendir", dl->dir);
@@ -1170,10 +1175,14 @@ static int _scan_file(const struct format_type *fmt, const char *vgname)
 					stack;
 					break;
 				}
+
+				log_debug_metadata("Scanning independent file %s for VG %s", path, scanned_vgname);
+
 				if ((vg = _vg_read_file_name(fid, scanned_vgname,
 							     path))) {
 					/* FIXME Store creation host in vg */
 					lvmcache_update_vg(vg, 0);
+					lvmcache_set_independent_location(vg->name);
 					release_vg(vg);
 				}
 			}
@@ -1298,11 +1307,16 @@ static int _scan_raw(const struct format_type *fmt, const char *vgname __attribu
 
 	raw_list = &((struct mda_lists *) fmt->private)->raws;
 
+	if (!dm_list_empty(raw_list))
+		log_debug_metadata("Scanning independent raw locations for %s", vgname ? vgname : "VGs");
+
 	fid.fmt = fmt;
 	dm_list_init(&fid.metadata_areas_in_use);
 	dm_list_init(&fid.metadata_areas_ignored);
 
 	dm_list_iterate_items(rl, raw_list) {
+		log_debug_metadata("Scanning independent dev %s", dev_name(rl->dev_area.dev));
+
 		/* FIXME We're reading mdah twice here... */
 		if (!dev_open_readonly(rl->dev_area.dev)) {
 			stack;
@@ -1317,8 +1331,10 @@ static int _scan_raw(const struct format_type *fmt, const char *vgname __attribu
 		/* TODO: caching as in read_metadata_location() (trigger this code?) */
 		if (read_metadata_location(fmt, mdah, NULL, &rl->dev_area, &vgsummary, NULL)) {
 			vg = _vg_read_raw_area(&fid, vgsummary.vgname, &rl->dev_area, NULL, NULL, NULL, 0);
-			if (vg)
+			if (vg) {
 				lvmcache_update_vg(vg, 0);
+				lvmcache_set_independent_location(vg->name);
+			}
 		}
 	close_dev:
 		if (!dev_close(rl->dev_area.dev))
@@ -1332,7 +1348,9 @@ static int _scan_raw(const struct format_type *fmt, const char *vgname __attribu
 
 static int _text_scan(const struct format_type *fmt, const char *vgname)
 {
-	return (_scan_file(fmt, vgname) & _scan_raw(fmt, vgname));
+	_scan_file(fmt, vgname);
+	_scan_raw(fmt, vgname);
+	return 1;
 }
 
 struct _write_single_mda_baton {