Re: [PATCH RFC v2 for-6.8/block 17/18] ext4: remove block_device_ejected()

Jan Kara
2023-12-11T17:04:05Z

On Mon 11-12-23 22:08:33, Yu Kuai wrote:
> From: Yu Kuai <yukuai3@huawei.com>
>
> block_device_ejected() is added by commit bdfe0cbd746a ("Revert
> "ext4: remove block_device_ejected"") in 2015. At that time 'bdi->wb'
> is destroyed synchronized from del_gendisk(), hence if ext4 is still
> mounted, and then mark_buffer_dirty() will reference destroyed 'wb'.
> However, such problem doesn't exist anymore:
>
> - commit d03f6cdc1fc4 ("block: Dynamically allocate and refcount
> backing_dev_info") switch bdi to use refcounting;
> - commit 13eec2363ef0 ("fs: Get proper reference for s_bdi"), will grab
> additional reference of bdi while mounting, so that 'bdi->wb' will not
> be destroyed until generic_shutdown_super().
>
> Hence remove this dead function block_device_ejected().
>
> Signed-off-by: Yu Kuai <yukuai3@huawei.com>

Agreed, this should not be needed anymore. We'll see whether this is true
also in practice :). Feel free to add:

Reviewed-by: Jan Kara <jack@suse.cz>

Honza
--
Jan Kara <jack@suse.com>
SUSE Labs, CR