From: NeilBrown <neilb@suse.de>
Date: Wed, 15 Dec 2010 22:07:51 +0000 (+1100)
Subject: Grow: check container is idle before freezing it.
X-Git-Tag: mdadm-3.2~179
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d7ca196cbda7ec5e6d2a3139a5545e3e0d57a67e;p=thirdparty%2Fmdadm.git

Grow: check container is idle before freezing it.

Before we freeze a container in preparation for growing a subarray, we
need to be sure all the subarrays are idle.

This test is racy as recovery could start at any moment following a
failure.  However it is still useful as it stops us from even trying
to start a reshape while a reshape or recovery is active.

Signed-off-by: NeilBrown <neilb@suse.de>
---

diff --git a/Grow.c b/Grow.c
index 222d755c..af605a86 100644
--- a/Grow.c
+++ b/Grow.c
@@ -467,17 +467,41 @@ static int child_same_size(int afd, struct mdinfo *sra, unsigned long blocks,
 			   int disks, int chunk, int level, int layout, int data,
 			   int dests, int *destfd, unsigned long long *destoffsets);
 
+static int check_idle(struct supertype *st)
+{
+	/* Check that all member arrays for this container, or the
+	 * container of this array, are idle
+	 */
+	int container_dev = (st->container_dev != NoMdDev
+			     ? st->container_dev : st->devnum);
+	char container[40];
+	struct mdstat_ent *ent, *e;
+	int is_idle = 1;
+	
+	fmt_devname(container, container_dev);
+	ent = mdstat_read(0, 0);
+	for (e = ent ; e; e = e->next) {
+		if (!is_container_member(e, container))
+			continue;
+		if (e->percent >= 0) {
+			is_idle = 0;
+			break;
+		}
+	}
+	free_mdstat(ent);
+	return is_idle;
+}
+
 static int freeze_container(struct supertype *st)
 {
 	int container_dev = (st->container_dev != NoMdDev
 			     ? st->container_dev : st->devnum);
-	char *container = devnum2devname(container_dev);
+	char container[40];
 
-	if (!container) {
-		fprintf(stderr, Name
-			": could not determine container name, freeze aborted\n");
-		return -2;
-	}
+	if (!check_idle(st))
+		return -1;
+	
+	fmt_devname(container, container_dev);
 
 	if (block_monitor(container, 1)) {
 		fprintf(stderr, Name ": failed to freeze container\n");
@@ -491,13 +515,9 @@ static void unfreeze_container(struct supertype *st)
 {
 	int container_dev = (st->container_dev != NoMdDev
 			     ? st->container_dev : st->devnum);
-	char *container = devnum2devname(container_dev);
-
-	if (!container) {
-		fprintf(stderr, Name
-			": could not determine container name, unfreeze aborted\n");
-		return;
-	}
+	char container[40];
+	
+	fmt_devname(container, container_dev);
 
 	unblock_monitor(container, 1);
 }