/*
* Send a notification to a client immediately after it registers.
* The result_t is a list of all the nodes that match their specified
* nodes of interest, all returned on the added list. This serves
* as a base of reference to the client. All future MD updates are
* relative to this list.
*/
static int
mdeg_notify_client_reg(mdeg_clnt_t *clnt)
{
md_t *mdp = NULL;
mde_str_cookie_t nname;
mde_str_cookie_t aname;
mde_cookie_t startnode;
int nnodes;
int nodechk;
mde_cookie_t *listp = NULL;
mdeg_result_t *mdeg_res = NULL;
int rv = MDEG_SUCCESS;
mutex_enter(&mdeg.lock);
/*
* Handle the special case where the node specification
* is NULL. In this case, call the client callback without
* any results. All processing is left to the client.
*/
if (clnt->pspec == NULL) {
/* call the client callback */
(*clnt->cb)(clnt->cb_arg, NULL);
goto done;
}
if ((mdp = md_get_handle()) == NULL) {
cmn_err(CE_WARN, "unable to retrieve current MD");
rv = MDEG_FAILURE;
goto done;
}
startnode = mdeg_find_start_node(mdp, clnt->pspec);
if (startnode == MDE_INVAL_ELEM_COOKIE) {
/* not much we can do */
cmn_err(CE_WARN, "unable to match node specifier");
rv = MDEG_FAILURE;
goto done;
}
/*
* Use zalloc to provide correct default values for the
* unused removed, match_prev, and match_curr lists.
*/
mdeg_res = kmem_zalloc(sizeof (mdeg_result_t), KM_SLEEP);
nname = md_find_name(mdp, clnt->nmatch->namep);
aname = md_find_name(mdp, "fwd");
nnodes = md_scan_dag(mdp, startnode, nname, aname, NULL);
if (nnodes == 0) {
MDEG_DBG("mdeg_notify_client_reg: no nodes of interest\n");
rv = MDEG_SUCCESS;
goto done;
} else if (nnodes == -1) {
MDEG_DBG("error scanning DAG\n");
rv = MDEG_FAILURE;
goto done;
}
MDEG_DBG("mdeg_notify_client_reg: %d node%s of interest\n",
nnodes, (nnodes == 1) ? "" : "s");
/* get the list of nodes of interest */
listp = kmem_alloc(sizeof (mde_cookie_t) * nnodes, KM_SLEEP);
nodechk = md_scan_dag(mdp, startnode, nname, aname, listp);
ASSERT(nodechk == nnodes);
mdeg_res->added.mdp = mdp;
mdeg_res->added.mdep = listp;
mdeg_res->added.nelem = nnodes;
/* call the client callback */
(*clnt->cb)(clnt->cb_arg, mdeg_res);
done:
mutex_exit(&mdeg.lock);
if (mdp)
(void) md_fini_handle(mdp);
if (listp)
kmem_free(listp, sizeof (mde_cookie_t) * nnodes);
if (mdeg_res)
kmem_free(mdeg_res, sizeof (mdeg_result_t));
return (rv);
}
static void
mdeg_notify_client(void *arg)
{
mdeg_clnt_t *clnt = (mdeg_clnt_t *)arg;
md_diff_cookie_t mdd = MD_INVAL_DIFF_COOKIE;
mdeg_result_t mdeg_res;
mde_cookie_t md_prev_start;
mde_cookie_t md_curr_start;
/*
* mdeg.rwlock must be held as a reader while this function
* executes. However, we do not need to acquire the lock as a
* reader here because it is held as a reader by the thread
* executing mdeg_notify_clients which triggers the execution
* of this function from a taskq. Since mdeg_notify_clients
* holds the lock as a reader until the taskq callbacks have
* completed, it will be held for the life of this function call.
* Furthermore, we must not attempt to acquire the lock as a
* reader with rw_enter because if there is a pending writer,
* we will block, creating a circular deadlock with this function,
* the writer, and mdeg_notify_clients. Since we do not need
* to acquire the lock, just assert that it is held.
*/
ASSERT(RW_READ_HELD(&mdeg.rwlock));
if (!mdeg.enabled) {
/* trying to shutdown */
MDEG_DBG("mdeg_notify_client: mdeg disabled, aborting\n");
goto cleanup;
}
/*
* Handle the special case where the node specification
* is NULL. In this case, call the client callback without
* any results. All processing is left to the client.
*/
if (clnt->pspec == NULL) {
/* call the client callback */
(*clnt->cb)(clnt->cb_arg, NULL);
MDEG_DBG("MDEG client callback done\n");
goto cleanup;
}
/* find our start nodes */
md_prev_start = mdeg_find_start_node(mdeg.md_prev, clnt->pspec);
if (md_prev_start == MDE_INVAL_ELEM_COOKIE) {
goto cleanup;
}
md_curr_start = mdeg_find_start_node(mdeg.md_curr, clnt->pspec);
if (md_curr_start == MDE_INVAL_ELEM_COOKIE) {
goto cleanup;
}
/* diff the MDs */
mdd = md_diff_init(mdeg.md_prev, md_prev_start, mdeg.md_curr,
md_curr_start, clnt->nmatch->namep, clnt->nmatch->matchp);
if (mdd == MD_INVAL_DIFF_COOKIE) {
MDEG_DBG("unable to diff MDs\n");
goto cleanup;
}
/*
* Cache the results of the diff
*/
mdeg_get_diff_results(mdd, &mdeg_res);
/* call the client callback */
(*clnt->cb)(clnt->cb_arg, &mdeg_res);
MDEG_DBG("MDEG client callback done\n");
cleanup:
if (mdd != MD_INVAL_DIFF_COOKIE)
(void) md_diff_fini(mdd);
}
static void
mdeg_notify_client(void *arg)
{
mdeg_clnt_t *clnt = (mdeg_clnt_t *)arg;
md_diff_cookie_t mdd = MD_INVAL_DIFF_COOKIE;
mdeg_result_t mdeg_res;
mde_cookie_t md_prev_start;
mde_cookie_t md_curr_start;
rw_enter(&mdeg.rwlock, RW_READER);
if (!mdeg.enabled) {
/* trying to shutdown */
MDEG_DBG("mdeg_notify_client: mdeg disabled, aborting\n");
goto cleanup;
}
/*
* Handle the special case where the node specification
* is NULL. In this case, call the client callback without
* any results. All processing is left to the client.
*/
if (clnt->pspec == NULL) {
/* call the client callback */
(*clnt->cb)(clnt->cb_arg, NULL);
MDEG_DBG("MDEG client callback done\n");
goto cleanup;
}
/* find our start nodes */
md_prev_start = mdeg_find_start_node(mdeg.md_prev, clnt->pspec);
if (md_prev_start == MDE_INVAL_ELEM_COOKIE) {
goto cleanup;
}
md_curr_start = mdeg_find_start_node(mdeg.md_curr, clnt->pspec);
if (md_curr_start == MDE_INVAL_ELEM_COOKIE) {
goto cleanup;
}
/* diff the MDs */
mdd = md_diff_init(mdeg.md_prev, md_prev_start, mdeg.md_curr,
md_curr_start, clnt->nmatch->namep, clnt->nmatch->matchp);
if (mdd == MD_INVAL_DIFF_COOKIE) {
MDEG_DBG("unable to diff MDs\n");
goto cleanup;
}
/*
* Cache the results of the diff
*/
mdeg_get_diff_results(mdd, &mdeg_res);
/* call the client callback */
(*clnt->cb)(clnt->cb_arg, &mdeg_res);
MDEG_DBG("MDEG client callback done\n");
cleanup:
rw_exit(&mdeg.rwlock);
if (mdd != MD_INVAL_DIFF_COOKIE)
(void) md_diff_fini(mdd);
}
