/*
* Given two dataset names, create an edge between them. For the source vertex,
* mark 'zv_visited' to indicate that we have seen this vertex, and not simply
* created it as a destination of another edge. If 'dest' is NULL, then this
* is an individual vertex (i.e. the starting vertex), so don't add an edge.
*/
static int
zfs_graph_add(libzfs_handle_t *hdl, zfs_graph_t *zgp, const char *source,
const char *dest, uint64_t txg)
{
zfs_vertex_t *svp, *dvp;
if ((svp = zfs_graph_lookup(hdl, zgp, source, 0)) == NULL)
return (-1);
svp->zv_visited = VISIT_SEEN;
if (dest != NULL) {
dvp = zfs_graph_lookup(hdl, zgp, dest, txg);
if (dvp == NULL)
return (-1);
if (zfs_vertex_add_edge(hdl, svp, dvp) != 0)
return (-1);
}
return (0);
}
/*
* 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);
}
/*
* Iterate over all children of the given dataset, adding any vertices as
* necessary. Returns 0 if no cloned snapshots were seen, -1 if there was an
* error, or 1 otherwise. This is a simple recursive algorithm - the ZFS
* namespace typically is very flat. We manually invoke the necessary ioctl()
* calls to avoid the overhead and additional semantics of zfs_open().
*/
static int
iterate_children(libzfs_handle_t *hdl, zfs_graph_t *zgp, const char *dataset)
{
zfs_cmd_t zc = { 0 };
int ret = 0, err;
zfs_vertex_t *zvp;
/*
* Look up the source vertex, and avoid it if we've seen it before.
*/
zvp = zfs_graph_lookup(hdl, zgp, dataset, 0);
if (zvp == NULL)
return (-1);
if (zvp->zv_visited == VISIT_SEEN)
return (0);
/*
* We check the clone parent here instead of within the loop, so that if
* the root dataset has been promoted from a clone, we find its parent
* appropriately.
*/
(void) strlcpy(zc.zc_name, dataset, sizeof (zc.zc_name));
if (ioctl(hdl->libzfs_fd, ZFS_IOC_OBJSET_STATS, &zc) == 0 &&
zc.zc_objset_stats.dds_clone_of[0] != '\0') {
if (zfs_graph_add(hdl, zgp, zc.zc_objset_stats.dds_clone_of,
zc.zc_name, zc.zc_objset_stats.dds_creation_txg) != 0)
return (-1);
}
for ((void) strlcpy(zc.zc_name, dataset, sizeof (zc.zc_name));
ioctl(hdl->libzfs_fd, ZFS_IOC_DATASET_LIST_NEXT, &zc) == 0;
(void) strlcpy(zc.zc_name, dataset, sizeof (zc.zc_name))) {
/*
* Ignore private dataset names.
*/
if (dataset_name_hidden(zc.zc_name))
continue;
/*
* Get statistics for this dataset, to determine the type of the
* dataset and clone statistics. If this fails, the dataset has
* since been removed, and we're pretty much screwed anyway.
*/
if (ioctl(hdl->libzfs_fd, ZFS_IOC_OBJSET_STATS, &zc) != 0)
continue;
/*
* Add an edge between the parent and the child.
*/
if (zfs_graph_add(hdl, zgp, dataset, zc.zc_name,
zc.zc_objset_stats.dds_creation_txg) != 0)
return (-1);
/*
* Iterate over all children
*/
err = iterate_children(hdl, zgp, zc.zc_name);
if (err == -1)
return (-1);
else if (err == 1)
ret = 1;
/*
* Indicate if we found a dataset with a non-zero clone count.
*/
if (zc.zc_objset_stats.dds_num_clones != 0)
ret = 1;
}
/*
* Now iterate over all snapshots.
*/
bzero(&zc, sizeof (zc));
for ((void) strlcpy(zc.zc_name, dataset, sizeof (zc.zc_name));
ioctl(hdl->libzfs_fd, ZFS_IOC_SNAPSHOT_LIST_NEXT, &zc) == 0;
(void) strlcpy(zc.zc_name, dataset, sizeof (zc.zc_name))) {
/*
* Get statistics for this dataset, to determine the type of the
* dataset and clone statistics. If this fails, the dataset has
* since been removed, and we're pretty much screwed anyway.
*/
if (ioctl(hdl->libzfs_fd, ZFS_IOC_OBJSET_STATS, &zc) != 0)
continue;
/*
* Add an edge between the parent and the child.
*/
if (zfs_graph_add(hdl, zgp, dataset, zc.zc_name,
zc.zc_objset_stats.dds_creation_txg) != 0)
return (-1);
/*
* Indicate if we found a dataset with a non-zero clone count.
*/
if (zc.zc_objset_stats.dds_num_clones != 0)
ret = 1;
}
zvp->zv_visited = VISIT_SEEN;
return (ret);
}
/*
* Iterate over all children of the given dataset, adding any vertices
* as necessary. Returns -1 if there was an error, or 0 otherwise.
* This is a simple recursive algorithm - the ZFS namespace typically
* is very flat. We manually invoke the necessary ioctl() calls to
* avoid the overhead and additional semantics of zfs_open().
*/
static int
iterate_children(libzfs_handle_t *hdl, zfs_graph_t *zgp, const char *dataset)
{
zfs_cmd_t zc = { 0 };
zfs_vertex_t *zvp;
/*
* Look up the source vertex, and avoid it if we've seen it before.
*/
zvp = zfs_graph_lookup(hdl, zgp, dataset, 0);
if (zvp == NULL)
return (-1);
if (zvp->zv_visited == VISIT_SEEN)
return (0);
/*
* Iterate over all children
*/
for ((void) strlcpy(zc.zc_name, dataset, sizeof (zc.zc_name));
ioctl(hdl->libzfs_fd, ZFS_IOC_DATASET_LIST_NEXT, &zc) == 0;
(void) strlcpy(zc.zc_name, dataset, sizeof (zc.zc_name))) {
/*
* Ignore private dataset names.
*/
if (dataset_name_hidden(zc.zc_name))
continue;
/*
* Get statistics for this dataset, to determine the type of the
* dataset and clone statistics. If this fails, the dataset has
* since been removed, and we're pretty much screwed anyway.
*/
zc.zc_objset_stats.dds_origin[0] = '\0';
if (ioctl(hdl->libzfs_fd, ZFS_IOC_OBJSET_STATS, &zc) != 0)
continue;
if (zc.zc_objset_stats.dds_origin[0] != '\0') {
if (zfs_graph_add(hdl, zgp,
zc.zc_objset_stats.dds_origin, zc.zc_name,
zc.zc_objset_stats.dds_creation_txg) != 0)
return (-1);
/*
* Count origins only if they are contained in the graph
*/
if (isa_child_of(zc.zc_objset_stats.dds_origin,
zgp->zg_root))
zgp->zg_clone_count--;
}
/*
* Add an edge between the parent and the child.
*/
if (zfs_graph_add(hdl, zgp, dataset, zc.zc_name,
zc.zc_objset_stats.dds_creation_txg) != 0)
return (-1);
/*
* Recursively visit child
*/
if (iterate_children(hdl, zgp, zc.zc_name))
return (-1);
}
/*
* Now iterate over all snapshots.
*/
bzero(&zc, sizeof (zc));
for ((void) strlcpy(zc.zc_name, dataset, sizeof (zc.zc_name));
ioctl(hdl->libzfs_fd, ZFS_IOC_SNAPSHOT_LIST_NEXT, &zc) == 0;
(void) strlcpy(zc.zc_name, dataset, sizeof (zc.zc_name))) {
/*
* Get statistics for this dataset, to determine the type of the
* dataset and clone statistics. If this fails, the dataset has
* since been removed, and we're pretty much screwed anyway.
*/
if (ioctl(hdl->libzfs_fd, ZFS_IOC_OBJSET_STATS, &zc) != 0)
continue;
/*
* Add an edge between the parent and the child.
*/
if (zfs_graph_add(hdl, zgp, dataset, zc.zc_name,
zc.zc_objset_stats.dds_creation_txg) != 0)
return (-1);
zgp->zg_clone_count += zc.zc_objset_stats.dds_num_clones;
}
zvp->zv_visited = VISIT_SEEN;
return (0);
}
