Re: [PATCH 5/5] fs: make umount(2) of the root killable on s_umount

[Jan Kara]

On Fri 23-10-26 20:39:34, Josef Bacik wrote:
> Unmounting the root of the caller doesn't unmount anything, it remounts
> the filesystem read-only.  So it has the same problem as a remount: it
> waits for s_umount in D state, can't be killed, and keeps every later
> reader of the lock waiting behind it.
> 
> Use down_write_killable() in do_umount_root().
> 
> Signed-off-by: Josef Bacik <josef@xxxxxxxxxxxxxx>

Look good. Feel free to add:

Reviewed-by: Jan Kara <jack@xxxxxxx>

								Honza

> ---
>  fs/namespace.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/namespace.c b/fs/namespace.c
> index 837f531e494b..b874accabf76 100644
> --- a/fs/namespace.c
> +++ b/fs/namespace.c
> @@ -1897,9 +1897,11 @@ static void shrink_submounts(struct mount *mnt);
>  
>  static int do_umount_root(struct super_block *sb)
>  {
> -	int ret = 0;
> +	int ret;
>  
> -	down_write(&sb->s_umount);
> +	ret = down_write_killable(&sb->s_umount);
> +	if (ret)
> +		return ret;
>  	if (!sb_rdonly(sb)) {
>  		struct fs_context *fc;
>  
> 
> -- 
> 2.55.0
> 
-- 
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR