Re: [PATCH] fsync on unmounting root

[Alexander Viro]

On Thu, 4 Jan 2001, Chris Mason wrote:

> Hi guys,
> 
> Looks like the prerelease, and at least test13 don't fsync the device when
> someone does an unmount on /
> 
> mount -o remount works, just unmounting the root misses the fsync.
> 
> This patch works for me:
> 
> -chris
> 
> --- linux/fs/super.c.1	Thu Jan  4 13:38:55 2001
> +++ linux/fs/super.c	Thu Jan  4 13:38:39 2001
> @@ -1031,8 +1031,12 @@
>  		 * we just try to remount it readonly.
>  		 */
>  		mntput(mnt);
> -		if (!(sb->s_flags & MS_RDONLY)) 
> +		if (!(sb->s_flags & MS_RDONLY)) {
> +			shrink_dcache_sb(sb);
> +			fsync_dev(sb->s_dev);
> +			acct_auto_close(sb->s_dev);
>  			retval = do_remount_sb(sb, MS_RDONLY, 0);
> +		}

I have a better suggestion: 

        if (mnt == current->fs->rootmnt && !umount_root) {
                mntput(mnt);
		return do_remount("/", 0, NULL);
	}