1 files changed, 9 insertions, 0 deletions
diff --git a/fs/super.c b/fs/super.c
index 938119a..3479ca6 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -773,7 +773,16 @@ int get_sb_bdev(struct file_system_type *fs_type,
 			goto error_bdev;
 		}
 
+		/*
+		 * s_umount nests inside bd_mutex during
+		 * __invalidate_device().  close_bdev_exclusive()
+		 * acquires bd_mutex and can't be called under
+		 * s_umount.  Drop s_umount temporarily.  This is safe
+		 * as we're holding an active reference.
+		 */
+		up_write(&s->s_umount);
 		close_bdev_exclusive(bdev, mode);
+		down_write(&s->s_umount);
 	} else {
 		char b[BDEVNAME_SIZE];