Re: [PATCH] UBIFS: kill BKL

[Adrian Hunter <adrian.hunter@nokia.com>]

Artem Bityutskiy wrote:
> From: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
> 
> The BKL was pushed down from VFS to the file-systems. It used
> to serialize mount/unmount/remount. UBIFS must be safe if several
> file-systems are mounted/unmounted/re-mounted at the same time,
> so kill kick the BKL out of UBIFS.
> 
> Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
> ---

Looks like protection is always provided by sb->s_umount

Missing {} below, btw.

>  fs/ubifs/super.c |   15 ++-------------
>  1 files changed, 2 insertions(+), 13 deletions(-)
> 
> diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c
> index 26d2e0d..4ad992f 100644
> --- a/fs/ubifs/super.c
> +++ b/fs/ubifs/super.c
> @@ -1726,8 +1726,6 @@ static void ubifs_put_super(struct super_block *sb)
>  	ubifs_msg("un-mount UBI device %d, volume %d", c->vi.ubi_num,
>  		  c->vi.vol_id);
>  
> -	lock_kernel();
> -
>  	/*
>  	 * The following asserts are only valid if there has not been a failure
>  	 * of the media. For example, there will be dirty inodes if we failed
> @@ -1792,8 +1790,6 @@ static void ubifs_put_super(struct super_block *sb)
>  	ubi_close_volume(c->ubi);
>  	mutex_unlock(&c->umount_mutex);
>  	kfree(c);
> -
> -	unlock_kernel();
>  }
>  
>  static int ubifs_remount_fs(struct super_block *sb, int *flags, char *data)
> @@ -1809,24 +1805,18 @@ static int ubifs_remount_fs(struct super_block *sb, int *flags, char *data)
>  		return err;
>  	}
>  
> -	lock_kernel();
>  	if ((sb->s_flags & MS_RDONLY) && !(*flags & MS_RDONLY)) {
>  		if (c->ro_media) {
>  			ubifs_msg("cannot re-mount due to prior errors");
> -			unlock_kernel();
>  			return -EROFS;
>  		}
>  		err = ubifs_remount_rw(c);
> -		if (err) {
> -			unlock_kernel();
> +		if (err)
>  			return err;
> -		}
>  	} else if (!(sb->s_flags & MS_RDONLY) && (*flags & MS_RDONLY)) {
> -		if (c->ro_media) {
> +		if (c->ro_media)

Missing {}

>  			ubifs_msg("cannot re-mount due to prior errors");
> -			unlock_kernel();
>  			return -EROFS;
> -		}
>  		ubifs_remount_ro(c);
>  	}
>  
> @@ -1839,7 +1829,6 @@ static int ubifs_remount_fs(struct super_block *sb, int *flags, char *data)
>  	}
>  
>  	ubifs_assert(c->lst.taken_empty_lebs > 0);
> -	unlock_kernel();
>  	return 0;
>  }
>