---

yaml
---
r: 273105
b: refs/heads/master
c: 7c2e708
h: refs/heads/master
i:
  273103: 82d3aeb
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 02fac1297eb3f471a27368271aadd285548297b0
+refs/heads/master: 7c2e70879fc0949b4220ee61b7c4553f6976a94d

trunk/fs/ext4/super.c

@@ -414,6 +414,22 @@ static void save_error_info(struct super_block *sb, const char *func,
 	ext4_commit_super(sb, 1);
 }
 
+/*
+ * The del_gendisk() function uninitializes the disk-specific data
+ * structures, including the bdi structure, without telling anyone
+ * else.  Once this happens, any attempt to call mark_buffer_dirty()
+ * (for example, by ext4_commit_super), will cause a kernel OOPS.
+ * This is a kludge to prevent these oops until we can put in a proper
+ * hook in del_gendisk() to inform the VFS and file system layers.
+ */
+static int block_device_ejected(struct super_block *sb)
+{
+	struct inode *bd_inode = sb->s_bdev->bd_inode;
+	struct backing_dev_info *bdi = bd_inode->i_mapping->backing_dev_info;
+
+	return bdi->dev == NULL;
+}
+
 
 /* Deal with the reporting of failure conditions on a filesystem such as
  * inconsistencies detected or read IO failures.
@@ -4072,7 +4088,7 @@ static int ext4_commit_super(struct super_block *sb, int sync)
 	struct buffer_head *sbh = EXT4_SB(sb)->s_sbh;
 	int error = 0;
 
-	if (!sbh)
+	if (!sbh || block_device_ejected(sb))
 		return error;
 	if (buffer_write_io_error(sbh)) {
 		/*