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Commit 7c2e7087 authored by Theodore Ts'o's avatar Theodore Ts'o
Browse files

ext4: add ext4-specific kludge to avoid an oops after the disk disappears 



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.

Fix this for now until we can fix things in an architecturally correct
way.

Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent 02fac129

fs/ext4/super.c

+17 −1
Original line number Diff line number Diff line
@@ -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)) {

		/*