/*
* Construct a complete graph of all necessary vertices. First, we iterate over
* only our object's children. If we don't find any cloned snapshots, then we
* simple return that. Otherwise, we have to start at the pool root and iterate
* over all datasets.
*/
static zfs_graph_t *
construct_graph(libzfs_handle_t *hdl, const char *dataset)
{
zfs_graph_t *zgp = zfs_graph_create(hdl, ZFS_GRAPH_SIZE);
zfs_cmd_t zc = { 0 };
int ret = 0;
if (zgp == NULL)
return (zgp);
/*
* We need to explicitly check whether this dataset has clones or not,
* since iterate_children() only checks the children.
*/
(void) strlcpy(zc.zc_name, dataset, sizeof (zc.zc_name));
(void) ioctl(hdl->libzfs_fd, ZFS_IOC_OBJSET_STATS, &zc);
if (zc.zc_objset_stats.dds_num_clones != 0 ||
(ret = iterate_children(hdl, zgp, dataset)) != 0) {
/*
* Determine pool name and try again.
*/
char *pool, *slash;
if ((slash = strchr(dataset, '/')) != NULL ||
(slash = strchr(dataset, '@')) != NULL) {
pool = zfs_alloc(hdl, slash - dataset + 1);
if (pool == NULL) {
zfs_graph_destroy(zgp);
return (NULL);
}
(void) strncpy(pool, dataset, slash - dataset);
pool[slash - dataset] = '\0';
if (iterate_children(hdl, zgp, pool) == -1 ||
zfs_graph_add(hdl, zgp, pool, NULL, 0) != 0) {
free(pool);
zfs_graph_destroy(zgp);
return (NULL);
}
free(pool);
}
}
if (ret == -1 || zfs_graph_add(hdl, zgp, dataset, NULL, 0) != 0) {
zfs_graph_destroy(zgp);
return (NULL);
}
return (zgp);
}
/*
* The only public interface for this file. Do the dirty work of constructing a
* child list for the given object. Construct the graph, do the toplogical
* sort, and then return the array of strings to the caller.
*
* The 'allowrecursion' parameter controls behavior when cycles are found. If
* it is set, the the cycle is ignored and the results returned as if the cycle
* did not exist. If it is not set, then the routine will generate an error if
* a cycle is found.
*/
int
get_dependents(libzfs_handle_t *hdl, boolean_t allowrecursion,
const char *dataset, char ***result, size_t *count)
{
zfs_graph_t *zgp;
zfs_vertex_t *zvp;
if ((zgp = construct_graph(hdl, dataset)) == NULL)
return (-1);
if ((*result = zfs_alloc(hdl,
zgp->zg_nvertex * sizeof (char *))) == NULL) {
zfs_graph_destroy(zgp);
return (-1);
}
if ((zvp = zfs_graph_lookup(hdl, zgp, dataset, 0)) == NULL) {
free(*result);
zfs_graph_destroy(zgp);
return (-1);
}
*count = 0;
if (topo_sort(hdl, allowrecursion, *result, count, zvp) != 0) {
free(*result);
zfs_graph_destroy(zgp);
return (-1);
}
/*
* Get rid of the last entry, which is our starting vertex and not
* strictly a dependent.
*/
assert(*count > 0);
free((*result)[*count - 1]);
(*count)--;
zfs_graph_destroy(zgp);
return (0);
}
/*
* Construct a complete graph of all necessary vertices. First, iterate over
* only our object's children. If no cloned snapshots are found, or all of
* the cloned snapshots are in this subtree then return a graph of the subtree.
* Otherwise, start at the root of the pool and iterate over all datasets.
*/
static zfs_graph_t *
construct_graph(libzfs_handle_t *hdl, const char *dataset)
{
zfs_graph_t *zgp = zfs_graph_create(hdl, dataset, ZFS_GRAPH_SIZE);
int ret = 0;
if (zgp == NULL)
return (zgp);
if ((strchr(dataset, '/') == NULL) ||
(external_dependents(hdl, zgp, dataset))) {
/*
* Determine pool name and try again.
*/
int len = strcspn(dataset, "/@") + 1;
char *pool = zfs_alloc(hdl, len);
if (pool == NULL) {
zfs_graph_destroy(zgp);
return (NULL);
}
(void) strlcpy(pool, dataset, len);
if (iterate_children(hdl, zgp, pool) == -1 ||
zfs_graph_add(hdl, zgp, pool, NULL, 0) != 0) {
free(pool);
zfs_graph_destroy(zgp);
return (NULL);
}
free(pool);
}
if (ret == -1 || zfs_graph_add(hdl, zgp, dataset, NULL, 0) != 0) {
zfs_graph_destroy(zgp);
return (NULL);
}
return (zgp);
}
