linux-kernel - Re: [PATCH] Fix d_path for lazy unmounts

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Message-Id: <200702141913.21944.agruen@suse.de>
Date:	Wed, 14 Feb 2007 19:13:21 -0800
From:	Andreas Gruenbacher <agruen@...e.de>
To:	Linus Torvalds <torvalds@...ux-foundation.org>
Cc:	linux-kernel@...r.kernel.org,
	Andrew Morton <akpm@...ux-foundation.org>,
	Al Viro <viro@....linux.org.uk>, linux-fsdevel@...r.kernel.org,
	Tony Jones <tonyj@...e.de>, Neil Brown <neilb@...e.de>,
	Christoph Hellwig <hch@....de>,
	Greg Kroah-Hartman <gregkh@...e.de>,
	walt <wa1ter@...ealbox.com>
Subject: Re: [PATCH] Fix d_path for lazy unmounts

On Wednesday 14 February 2007 14:57, Andreas Gruenbacher wrote:
> [1] Always make disconnected paths relative:
>
> From all these choices, I actually like [1] best, together with hiding
> unreachable mount points in /proc/$pid/mounts and /proc/$pid/mountstats:
> there is no real point in pretending that unreachable paths are reachable;
> whichever process uses these paths is just as much in error when trying
> from the pwd as when trying from the chroot.

So here is how this could be implemented. See the lengthy explanations in the 
patch headers, too.

d_path-lazy-unmounts.diff

	- Now fails sys_getcwd() with -ENOENT in case the path computed
	  doesn't lead to the chroot.
	- No longer reports empty paths, but report '.' in that case
	  instead.
	- Incorporates Neil's other minor feedback.

no-unreachable-paths.diff

	Hide unreachable mount points in /proc/mounts and /proc/$PID/mountstats.
	In particular, this includes the rootfs mount for all processes that
	are not chroot()ed in that mount.

Andreas

View attachment "d_path-lazy-unmounts.diff" of type "text/x-diff" (8028 bytes)

View attachment "no-unreachable-paths.diff" of type "text/x-diff" (5229 bytes)