From: Christoph Hellwig <hch-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>
Subject: Re: [PATCH 2/3] vfs, writeback: replace FS_CGROUP_WRITEBACK with
 MS_CGROUPWB
Date: Sat, 13 Jun 2015 09:16:08 -0700
Message-ID: <20150613161608.GA29414@infradead.org>
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To: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
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On Fri, Jun 12, 2015 at 04:57:33PM -0500, Tejun Heo wrote:
> FS_CGROUP_WRITEBACK indicates whether a file_system_type supports
> cgroup writeback; however, different super_blocks of the same
> file_system_type may or may not support cgroup writeback depending on
> filesystem options.  This patch replaces FS_CGROUP_WRITEBACK with a
> kernel-internal super_block->s_flags MS_CGROUPWB.  The concatenated
> and abbreviated name is for consistency with other MS_* flags.

Nak.  As the uapi part makes it obvious the MS_ namespace is part
of the userspace ABI.  Please add a new in-kernel flags field instead.