Remove stopped arrays.

When an array becomes inactive, clean up and forget it.

This involves signalling the manager.

managemon.c

@@ -75,6 +75,7 @@
 #include	"mdadm.h"
 #include	"mdmon.h"
 #include	<sys/socket.h>
+#include	<signal.h>
 
 static void close_aa(struct active_array *aa)
 {
@@ -116,6 +117,17 @@ static void write_wakeup(struct supertype *c)
 	read(c->mon_pipe[0], &err, 1);
 }
 
+static void remove_old(void)
+{
+	if (discard_this) {
+		discard_this->next = NULL;
+		free_aa(discard_this);
+		if (pending_discard == discard_this)
+			pending_discard = NULL;
+		discard_this = NULL;
+	}
+}
+
 static void replace_array(struct supertype *container,
 			  struct active_array *old,
 			  struct active_array *new)
@@ -126,16 +138,12 @@ static void replace_array(struct supertype *container,
 	 * and put it on 'discard_this'.  We take it from there
 	 * and discard it.
 	 */
-
+	remove_old();
 	while (pending_discard) {
+		write_wakeup(container);
 		while (discard_this == NULL)
 			sleep(1);
-		if (discard_this != pending_discard)
-			abort();
-		discard_this->next = NULL;
-		free_aa(discard_this);
-		discard_this = NULL;
-		pending_discard = NULL;
+		remove_old();
 	}
 	pending_discard = old;
 	new->replaces = old;
@@ -144,7 +152,6 @@ static void replace_array(struct supertype *container,
 	write_wakeup(container);
 }
 
-
 static void manage_container(struct mdstat_ent *mdstat,
 			     struct supertype *container)
 {
@@ -368,11 +375,26 @@ void read_sock(struct supertype *container)
 
 	close(fd);
 }
+
+static int woke = 0;
+void wake_me(int sig)
+{
+	woke = 1;
+}
+
 void do_manager(struct supertype *container)
 {
 	struct mdstat_ent *mdstat;
+	sigset_t block, orig;
+
+	sigemptyset(&block);
+	sigaddset(&block, SIGUSR1);
+
+	signal(SIGUSR1, wake_me);
 
 	do {
+		woke = 0;
+
 		mdstat = mdstat_read(1, 0);
 
 		manage(mdstat, container);
@@ -381,6 +403,11 @@ void do_manager(struct supertype *container)
 
 		free_mdstat(mdstat);
 
-		mdstat_wait_fd(container->sock);
+		remove_old();
+
+		sigprocmask(SIG_SETMASK, &block, &orig);
+		if (woke == 0)
+			mdstat_wait_fd(container->sock, &orig);
+		sigprocmask(SIG_SETMASK, &orig, NULL);
 	} while(1);
 }

mdadm.h

@@ -292,7 +292,7 @@ struct mdstat_ent {
 extern struct mdstat_ent *mdstat_read(int hold, int start);
 extern void free_mdstat(struct mdstat_ent *ms);
 extern void mdstat_wait(int seconds);
-extern void mdstat_wait_fd(int fd);
+extern void mdstat_wait_fd(int fd, const sigset_t *sigmask);
 extern int mddev_busy(int devnum);
 
 struct map_ent {

mdmon.c

@@ -48,6 +48,12 @@ struct md_generic_cmd *active_cmd;
 int run_child(void *v)
 {
 	struct supertype *c = v;
+	sigset_t set;
+	/* SIGUSR is sent from child to parent,  So child must block it */
+	sigemptyset(&set);
+	sigaddset(&set, SIGUSR1);
+	sigprocmask(SIG_BLOCK, &set, NULL);
+
 	do_monitor(c);
 	return 0;
 }

mdstat.c

@@ -272,7 +272,7 @@ void mdstat_wait(int seconds)
 	select(mdstat_fd >2 ? mdstat_fd+1:3, NULL, NULL, &fds, &tm);
 }
 
-void mdstat_wait_fd(int fd)
+void mdstat_wait_fd(int fd, const sigset_t *sigmask)
 {
 	fd_set fds, rfds;
 
@@ -282,7 +282,8 @@ void mdstat_wait_fd(int fd)
 		FD_SET(mdstat_fd, &fds);
 	FD_SET(fd, &rfds);
 
-	select(mdstat_fd >2 ? mdstat_fd+1:3, &rfds, NULL, &fds, NULL);
+	pselect(mdstat_fd >2 ? mdstat_fd+1:3, &rfds, NULL, &fds,
+		NULL, sigmask);
 }
 
 int mddev_busy(int devnum)

monitor.c

@@ -3,7 +3,7 @@
 #include "mdmon.h"
 
 #include <sys/select.h>
-
+#include <signal.h>
 
 static char *array_states[] = {
 	"clear", "inactive", "suspended", "readonly", "read-auto",
@@ -152,6 +152,10 @@ int read_dev_state(int fd)
 	return rv;
 }
 
+static void signal_manager(void)
+{
+	kill(getpid(), SIGUSR1);
+}
 
 /* Monitor a set of active md arrays - all of which share the
  * same metadata - and respond to events that require
@@ -432,28 +436,41 @@ static int handle_pipe(struct md_generic_cmd *cmd, struct active_array *aa)
 	return -1;
 }
 
-static int wait_and_act(struct active_array *aa, int pfd, int monfd, int nowait)
+static int wait_and_act(struct active_array **aap, int pfd,
+			int monfd, int nowait)
 {
 	fd_set rfds;
 	int maxfd = 0;
-	struct active_array *a;
+	struct active_array *a, **ap;
 	int rv;
 	struct mdinfo *mdi;
 
 	FD_ZERO(&rfds);
 
 	add_fd(&rfds, &maxfd, pfd);
-	for (a = aa ; a ; a = a->next) {
-		/* once an array has been deactivated only the manager
-		 * thread can make us care about it again
+	for (ap = aap ; *ap ;) {
+		a = *ap;
+		/* once an array has been deactivated we want to
+		 * ask the manager to discard it.
 		 */
-		if (!a->container)
+		if (!a->container) {
+			if (discard_this) {
+				ap = &(*ap)->next;
+				continue;
+			}
+			*ap = a->next;
+			a->next = NULL;
+			discard_this = a;
+			signal_manager();
 			continue;
+		}
 
 		add_fd(&rfds, &maxfd, a->info.state_fd);
 		add_fd(&rfds, &maxfd, a->action_fd);
 		for (mdi = a->info.devs ; mdi ; mdi = mdi->next)
 			add_fd(&rfds, &maxfd, mdi->state_fd);
+
+		ap = &(*ap)->next;
 	}
 
 	if (!nowait) {
@@ -466,12 +483,12 @@ static int wait_and_act(struct active_array *aa, int pfd, int monfd, int nowait)
 			int err = -1;
 
 			if (read(pfd, &err, 1) > 0)
-				err = handle_pipe(active_cmd, aa);
+				err = handle_pipe(active_cmd, *aap);
 			write(monfd, &err, 1);
 		}
 	}
 
-	for (a = aa; a ; a = a->next) {
+	for (a = *aap; a ; a = a->next) {
 		if (a->replaces && !discard_this) {
 			struct active_array **ap;
 			for (ap = &a->next; *ap && *ap != a->replaces;
@@ -481,18 +498,19 @@ static int wait_and_act(struct active_array *aa, int pfd, int monfd, int nowait)
 				*ap = (*ap)->next;
 			discard_this = a->replaces;
 			a->replaces = NULL;
+			signal_manager();
 		}
 		if (a->container)
 			rv += read_and_act(a);
 	}
 
 	/* propagate failures across container members */
-	for (a = aa; a ; a = a->next) {
+	for (a = *aap; a ; a = a->next) {
 		if (!a->container)
 			continue;
 		for (mdi = a->info.devs ; mdi ; mdi = mdi->next)
 			if (mdi->curr_state & DS_FAULTY)
-				reconcile_failed(aa, mdi);
+				reconcile_failed(*aap, mdi);
 	}
 
 	return rv;
@@ -503,7 +521,7 @@ void do_monitor(struct supertype *container)
 	int rv;
 	int first = 1;
 	do {
-		rv = wait_and_act(container->arrays, container->mgr_pipe[0],
+		rv = wait_and_act(&container->arrays, container->mgr_pipe[0],
 				  container->mon_pipe[1], first);
 		first = 0;
 	} while (rv >= 0);