o snapshot support for the text format.

The logical_volumes, and snapshots sections of the text format are now
optional.

lib/format_text/export.c

@@ -338,6 +338,12 @@ static int _print_lvs(struct formatter *f, struct volume_group *vg)
 	char buffer[256];
 	int seg_count;
 
+	/*
+	 * Don't bother with an lv section if there are no lvs.
+	 */
+	if (list_empty(&vg->lvs))
+		return 1;
+
 	_out(f, "logical_volumes {");
 	_nl(f);
 	_inc_indent(f);
@@ -381,6 +387,55 @@ static int _print_lvs(struct formatter *f, struct volume_group *vg)
 	return 1;
 }
 
+static int _print_snapshot(struct formatter *f, struct snapshot *s,
+			   unsigned int count)
+{
+	_nl(f);
+	_out(f, "snapshot%u {", count);
+	_inc_indent(f);
+
+	_out(f, "chunk_size = %u", s->chunk_size);
+	_out(f, "origin = \"%s\"", s->origin->name);
+	_out(f, "cow_store = \"%s\"", s->cow->name);
+
+	_dec_indent(f);
+	_out(f, "}");
+
+	return 1;
+}
+
+static int _print_snapshots(struct formatter *f, struct volume_group *vg)
+{
+	struct list *sh;
+	struct snapshot *s;
+	unsigned int count = 0;
+
+	/*
+	 * Don't bother with a snapshot section if there are no
+	 * snapshots.
+	 */
+	if (list_empty(&vg->snapshots))
+		return 1;
+
+	_out(f, "snapshots {");
+	_nl(f);
+	_inc_indent(f);
+
+	list_iterate (sh, &vg->snapshots) {
+		s = list_item(sh, struct snapshot_list)->snapshot;
+
+		if (!_print_snapshot(f, s, count++)) {
+			stack;
+			return 0;
+		}
+	}
+
+	_dec_indent(f);
+	_out(f, "}");
+
+	return 1;
+}
+
 /*
  * In the text format we refer to pv's as 'pv1',
  * 'pv2' etc.  This function builds a hash table
@@ -467,15 +522,17 @@ int text_vg_export(FILE *fp, struct volume_group *vg, const char *desc)
 		fail;
 
 	_nl(f);
-
 	if (!_print_pvs(f, vg))
 		fail;
 
 	_nl(f);
-
 	if (!_print_lvs(f, vg))
 		fail;
 
+	_nl(f);
+	if (!_print_snapshots(f, vg))
+		fail;
+
 #undef fail
 
 	_dec_indent(f);

lib/format_text/import.c

@@ -398,17 +398,71 @@ static int _read_lv(struct pool *mem,
 	return 1;
 }
 
+static int _read_snapshot(struct pool *mem,
+			  struct volume_group *vg, struct config_node *sn,
+			  struct config_node *vgn, struct hash_table *pv_hash,
+			  struct uuid_map *um)
+{
+	uint32_t chunk_size;
+	const char *org_name, *cow_name;
+	struct logical_volume *org, *cow;
+
+	if (!(sn = sn->child)) {
+		log_err("Empty snapshot section.");
+		return 0;
+	}
+
+	if (!_read_uint32(sn, "chunk_size", &chunk_size)) {
+		log_err("Couldn't read chunk size for snapshot.");
+		return 0;
+	}
+
+	if (!(cow_name = find_config_str(sn, "cow_store", '/', NULL))) {
+		log_err("Snapshot cow storage not specified.");
+		return 0;
+	}
+
+	if (!(org_name = find_config_str(sn, "origin", '/', NULL))) {
+		log_err("Snapshot origin not specified.");
+		return 0;
+	}
+
+	if (!(cow = find_lv(vg, cow_name))) {
+		log_err("Unknown logical volume specified for "
+			"snapshot cow store.");
+		return 0;
+	}
+
+	if (!(org = find_lv(vg, org_name))) {
+		log_err("Unknown logical volume specified for "
+			"snapshot origin.");
+		return 0;
+	}
+
+	if (!vg_add_snapshot(vg, org, cow, 1, chunk_size)) {
+		stack;
+		return 0;
+	}
+
+	return 1;
+}
+
 static int _read_sections(const char *section, section_fn fn,
 			  struct pool *mem,
 			  struct volume_group *vg, struct config_node *vgn,
 			  struct hash_table *pv_hash,
-			  struct uuid_map *um)
+			  struct uuid_map *um,
+			  int optional)
 {
 	struct config_node *n;
 
 	if (!(n = find_config_node(vgn, section, '/'))) {
-		log_err("Couldn't find section '%s'.", section);
+		if (!optional) {
-		return 0;
+			log_err("Couldn't find section '%s'.", section);
+			return 0;
+		}
+
+		return 1;
 	}
 
 	for (n = n->child; n; n = n->sib) {
@@ -514,7 +568,7 @@ static struct volume_group *_read_vg(struct pool *mem, struct config_file *cf,
 
 	list_init(&vg->pvs);
 	if (!_read_sections("physical_volumes", _read_pv, mem, vg,
-			    vgn, pv_hash, um)) {
+			    vgn, pv_hash, um, 0)) {
 		log_err("Couldn't find all physical volumes for volume "
 			"group %s.", vg->name);
 		goto bad;
@@ -522,12 +576,20 @@ static struct volume_group *_read_vg(struct pool *mem, struct config_file *cf,
 
 	list_init(&vg->lvs);
 	if (!_read_sections("logical_volumes", _read_lv, mem, vg,
-			    vgn, pv_hash, um)) {
+			    vgn, pv_hash, um, 1)) {
 		log_err("Couldn't read all logical volumes for volume "
 			"group %s.", vg->name);
 		goto bad;
 	}
 
+	list_init(&vg->snapshots);
+	if (!_read_sections("snapshots", _read_snapshot, mem, vg,
+			    vgn, pv_hash, um, 1)) {
+		log_err("Couldn't read all snapshots for volume group %s.",
+			vg->name);
+		goto bad;
+	}
+
 	hash_destroy(pv_hash);
 
 	/*