lvm2/lib/metadata/snapshot_manip.c

/*
 * Copyright (C) 2002 Sistina Software (UK) Limited.
 *
 * This file is released under the LGPL.
 */

#include "log.h"
#include "metadata.h"
#include "toolcontext.h"

int lv_is_origin(struct logical_volume *lv)
{
	struct list *slh;
	struct snapshot *s;

	list_iterate (slh, &lv->vg->snapshots) {
		s = list_item(slh, struct snapshot_list)->snapshot;
		if (s->origin == lv)
			return 1;
	}

	return 0;
}

int lv_is_cow(struct logical_volume *lv)
{
	struct list *slh;
	struct snapshot *s;

	list_iterate (slh, &lv->vg->snapshots) {
		s = list_item(slh, struct snapshot_list)->snapshot;
		if (s->cow == lv)
			return 1;
	}

	return 0;
}

struct snapshot *find_cow(struct logical_volume *lv)
{
	struct list *slh;
	struct snapshot *s;

	list_iterate (slh, &lv->vg->snapshots) {
		s = list_item(slh, struct snapshot_list)->snapshot;
		if (s->cow == lv)
			return s;
	}

	return NULL;
}

int vg_add_snapshot(struct logical_volume *origin,
		    struct logical_volume *cow,
		    int persistent,
		    uint32_t chunk_size)
{
	struct snapshot *s;
	struct snapshot_list *sl;
	struct pool *mem = origin->vg->cmd->mem;

	/*
	 * Is the cow device already being used ?
	 */
	if (lv_is_cow(cow)) {
		log_err("'%s' is already in use as a snapshot.", cow->name);
		return 0;
	}

	if (!(s = pool_alloc(mem, sizeof(*s)))) {
		stack;
		return 0;
	}

	s->persistent = persistent;
	s->chunk_size = chunk_size;
	s->origin = origin;
	s->cow = cow;

	if (!(sl = pool_alloc(mem, sizeof(*sl)))) {
		stack;
		pool_free(mem, s);
		return 0;
	}

	sl->snapshot = s;
	list_add(&origin->vg->snapshots, &sl->list);

	return 1;
}

int vg_remove_snapshot(struct volume_group *vg, struct logical_volume *cow)
{
	struct list *slh;
	struct snapshot_list *sl;

	list_iterate (slh, &vg->snapshots) {
		sl = list_item(slh, struct snapshot_list);

		if (sl->snapshot->cow == cow) {
			list_del(slh);
			return 1;
		}
	}

	/* fail */
	log_err("Asked to remove an unknown snapshot.");
	return 0;
}