Re: [patch] VFS: extend /proc/mounts

[Andrew Morton <akpm@linux-foundation.org>]

On Wed, 16 Jan 2008 23:12:31 +0100
Miklos Szeredi <miklos@szeredi.hu> wrote:

> The reason, why this patch was dug up, is that if the bdi-sysfs patch
> is going to use device numbers to identify BDIs, then there should be
> a way for the user to map the device number into mount(s).
> 
> But it's useful regardless of the bdi-sysfs patch.

Don't know what that is.

> Can this be added to -mm?
> 
> In theory it could break userspace, but I think it's very unlikely to
> do so, because stuff is added only at the end of the lines, and
> because most programs probably parse it through the libc interface
> which is not broken by this change.  Despite this, it should be tested
> on as many systems as possible.

Seems like a plain bad idea to me.  There will be any number of home-made
/proc/mounts parsers and we don't know what they do.

> - for mount ID's use IRA instead of a 32bit counter, which could overflow

don't know what an IRA is.

> - print canonical ID's (smallest one within the peer group) for peers
>   and master, this is more useful, than a random ID within the same namespace
> - fix a couple of small bugs
> - style fixes
> 
> Signed-off-by: Ram Pai <linuxram@us.ibm.com>
> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

Both the newly-added inlines in this patch are wrong.  They will result in
a larger and slower kernel.  This should be very well known by now.