Merge commit 'v2.6.32-rc8' into HEAD

1 files changed, 17 insertions, 0 deletions

diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 5a37e205571..11aee09dd2a 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -610,9 +610,26 @@ static void bdi_wb_shutdown(struct backing_dev_info *bdi)
 		kthread_stop(wb->task);
 }
 
+/*
+ * This bdi is going away now, make sure that no super_blocks point to it
+ */
+static void bdi_prune_sb(struct backing_dev_info *bdi)
+{
+	struct super_block *sb;
+
+	spin_lock(&sb_lock);
+	list_for_each_entry(sb, &super_blocks, s_list) {
+		if (sb->s_bdi == bdi)
+			sb->s_bdi = NULL;
+	}
+	spin_unlock(&sb_lock);
+}
+
 void bdi_unregister(struct backing_dev_info *bdi)
 {
 	if (bdi->dev) {
+		bdi_prune_sb(bdi);
+
 		if (!bdi_cap_flush_forker(bdi))
 			bdi_wb_shutdown(bdi);
 		bdi_debug_unregister(bdi);