[Ocfs2-devel] [PATCH 4/4] Implement "GROUP_ADD" for online resize.take 3

[Joel Becker <Joel.Becker@oracle.com>]

On Fri, Dec 14, 2007 at 03:56:41PM +0800, Tao Ma wrote:
> 2. For every new groups, tunefs.ocfs2 will call OCFS2_IOC_GROUP_ADD
>    to add them one by one. The new group descriptor is initialized
>    in userspace, we only check it in the kernel and update the
>    global_bitap, super blocks etc.

	I like the patches overall.  They are clean and straightforward.

> +	if (cluster < total_clusters)
> +		mlog(0, "add a group which is in the current volume.\n");
> +	else if (input->chain >= cl_count)
> +		mlog(0, "input chain exceeds the limit.\n");
> +	else if (next_free != cl_count && next_free != input->chain)
> +		mlog(0, "the add group should be in chain %u\n", next_free);
> +	else if (total_clusters + input->clusters < total_clusters)
> +		mlog(0, "add group's clusters overflow.\n");
> +	else if (input->clusters > cl_cpg)
> +		mlog(0, "the cluster exceeds the maximum of a group\n");
> +	else if (input->frees > input->clusters)
> +		mlog(0, "the free cluster exceeds the total clusters\n");
> +	else if (total_clusters % cl_cpg != 0)
> +		mlog(0, "the last group isn't full. Use group extend first.\n");
> +	else if (input->group != ocfs2_which_cluster_group(inode, cluster))
> +		mlog(0, "group blkno is invalid\n");
> +	else if ((ret = ocfs2_check_new_group(inode, di, input, group_bh)))
> +		mlog(0, "group descriptor check failed.\n");
> +	else
> +		ret = 0;

	These are some great errors, but the user will never see them.
tunefs.ocfs2 will just report "Invalid argument", which isn't very
helpful.  The same goes for the errors in the group check function,
which returns -EIO.  I'd love to see a way for the user to see them.
Either targeted errno values that tunefs can translate into strings, or
mlogs in dmesg so that tunefs can say "see dmesg for more info".
Something like that.  Mark points out that this should only be for real
errors, not things that are "normal operation" like ENOSPC.

Joel

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Joel Becker
Principal Software Developer
Oracle
E-mail: joel.becker@oracle.com
Phone: (650) 506-8127