--wait or -W will wait for resync activity to finish on the given devices.

ChangeLog

@@ -17,6 +17,8 @@ Changes Prior to this release
 	kernel, and it not reset when the reshape finishes.
     -   Change 'Device Size' to 'Used Dev Size' because it only shows how
 	much of each device is actually used, not how big they are.
+    -   --wait or -W will wait for resync activity to finish on the given
+	devices.
 
 Changes Prior to 2.5.6 release
     -   Fix bug which meant "bitmap=xxx" in mdadm.conf was not handled

Monitor.c

@@ -553,3 +553,38 @@ static void alert(char *event, char *dev, char *disc, char *mailaddr, char *mail
 			syslog(priority, "%s event detected on md device %s", event, dev);
 	}
 }
+
+/* Not really Monitor but ... */
+int Wait(char *dev)
+{
+	struct stat stb;
+	int devnum;
+	int rv = 1;
+
+	if (stat(dev, &stb) != 0) {
+		fprintf(stderr, Name ": Cannot find %s: %s\n", dev,
+			strerror(errno));
+		return 2;
+	}
+	if (major(stb.st_rdev) == MD_MAJOR)
+		devnum = minor(stb.st_rdev);
+	else
+		devnum = -minor(stb.st_rdev)/16;
+
+	while(1) {
+		struct mdstat_ent *ms = mdstat_read(1, 0);
+		struct mdstat_ent *e;
+
+		for (e=ms ; e; e=e->next)
+			if (e->devnum == devnum)
+				break;
+
+		if (!e || e->percent < 0) {
+			free_mdstat(ms);
+			return rv;
+		}
+		free(ms);
+		rv = 0;
+		mdstat_wait(5);
+	}
+}

ReadMe.c

@@ -91,8 +91,8 @@ char Version[] = Name " - v2.5.6 - 9 November 2006\n";
  *     At the time if writing, there is only minimal support.
  */
 
-char short_options[]="-ABCDEFGQhVXvqbc:i:l:p:m:n:x:u:c:d:z:U:sarfRSow1tye:";
-char short_bitmap_auto_options[]="-ABCDEFGQhVXvqb:c:i:l:p:m:n:x:u:c:d:z:U:sa:rfRSow1tye:";
+char short_options[]="-ABCDEFGQhVXWvqbc:i:l:p:m:n:x:u:c:d:z:U:sarfRSow1tye:";
+char short_bitmap_auto_options[]="-ABCDEFGQhVXWvqb:c:i:l:p:m:n:x:u:c:d:z:U:sa:rfRSow1tye:";
 
 struct option long_options[] = {
     {"manage",    0, 0, '@'},
@@ -160,6 +160,7 @@ struct option long_options[] = {
     {"readonly",  0, 0, 'o'},
     {"readwrite", 0, 0, 'w'},
     {"no-degraded",0,0,  NoDegraded },
+    {"wait",	  0, 0, 'W'},
 
     /* For Detail/Examine */
     {"brief",	  0, 0, 'b'},
@@ -296,6 +297,7 @@ char OptionHelp[] =
 "  --readonly    -o   : mark array as readonly\n"
 "  --readwrite   -w   : mark array as readwrite\n"
 "  --zero-superblock  : erase the MD superblock from a device.\n"
+"  --wait        -W   : wait for recovery/resync/reshape to finish.\n"
 ;
 */
 
@@ -459,6 +461,7 @@ char Help_misc[] =
 "  --readonly    -o   : mark array as readonly\n"
 "  --readwrite   -w   : mark array as readwrite\n"
 "  --test        -t   : exit status 0 if ok, 1 if degrade, 2 if dead, 4 if missing\n"
+"  --wait        -W   : wait for resync/rebuild/recovery to finish\n"
 ;
 
 char Help_monitor[] =

mdadm.8

@@ -931,6 +931,14 @@ the exit status of
 .I mdadm
 is set to reflect the status of the device.
 
+.TP
+.BR -W ", " --wait
+For each md device given, wait for any resync, recovery, or reshape
+activity to finish before returning.
+.I mdadm
+will return with success if it actually waited for every device
+listed, otherwise it will return failure.
+
 .SH For Monitor mode:
 .TP
 .BR -m ", " --mail

mdadm.c

@@ -201,6 +201,7 @@ int main(int argc, char *argv[])
 		case 'S':
 		case 'o':
 		case 'w':
+		case 'W':
 		case 'K': if (!mode) newmode = MISC; break;
 		}
 		if (mode && newmode == mode) {
@@ -742,6 +743,7 @@ int main(int argc, char *argv[])
 		case O(MISC,'X'):
 		case O(MISC,'o'):
 		case O(MISC,'w'):
+		case O(MISC,'W'):
 			if (devmode && devmode != opt &&
 			    (devmode == 'E' || (opt == 'E' && devmode != 'Q'))) {
 				fprintf(stderr, Name ": --examine/-E cannot be given with -%c\n",
@@ -1138,7 +1140,6 @@ int main(int argc, char *argv[])
 			    bitmap_file, bitmap_chunk, write_behind, delay);
 		break;
 	case MISC:
-
 		if (devmode == 'E') {
 			if (devlist == NULL && !scan) {
 				fprintf(stderr, Name ": No devices to examine\n");
@@ -1219,6 +1220,8 @@ int main(int argc, char *argv[])
 					rv |= Query(dv->devname); continue;
 				case 'X':
 					rv |= ExamineBitmap(dv->devname, brief, ss); continue;
+				case 'W':
+					rv |= Wait(dv->devname); continue;
 				}
 				mdfd = open_mddev(dv->devname, 1);
 				if (mdfd>=0) {

mdadm.h

@@ -421,6 +421,7 @@ extern int Monitor(mddev_dev_t devlist,
 		   int dosyslog, int test, char *pidfile);
 
 extern int Kill(char *dev, int force, int quiet);
+extern int Wait(char *dev);
 
 extern int CreateBitmap(char *filename, int force, char uuid[16],
 			unsigned long chunksize, unsigned long daemon_sleep,