diff --git a/mm/backing-dev.c b/mm/backing-dev.c index 5a37e205571785cfcc93ee7b4b95180df4e951e4..1065b715ef644e74836d4adf3c877c17d654b542 100644 --- a/mm/backing-dev.c +++ b/mm/backing-dev.c @@ -610,6 +610,21 @@ 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) { @@ -682,6 +697,7 @@ void bdi_destroy(struct backing_dev_info *bdi) spin_unlock(&inode_lock); } + bdi_prune_sb(bdi); bdi_unregister(bdi); for (i = 0; i < NR_BDI_STAT_ITEMS; i++)