From: Andy Whitcroft <apw@canonical.com>
To: Miklos Szeredi <miklos@szeredi.hu>
Cc: viro@ZenIV.linux.org.uk, linux-fsdevel@vger.kernel.org,
linux-kernel@vger.kernel.org, akpm@linux-foundation.org,
nbd@openwrt.org, neilb@suse.de, hramrach@centrum.cz,
jordipujolp@gmail.com, mszeredi@suse.cz
Subject: Re: [PATCH 0/7] overlay filesystem v9
Date: Thu, 19 May 2011 17:37:09 +0100 [thread overview]
Message-ID: <20110519163709.GH3702@shadowen.org> (raw)
In-Reply-To: <1305635452-14835-1-git-send-email-miklos@szeredi.hu>
On Tue, May 17, 2011 at 02:30:45PM +0200, Miklos Szeredi wrote:
> Here's an updated version of the overlay filesystem.
>
> Git tree is here:
>
> git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs.git overlayfs.v9
Ok I pulled this into the Ubuntu kernel and made an Ubuntu Live CD
for testing. Overall it worked pretty well, no hangs, no crashes,
performance seemed reasonable. We hit one issue with hard links which
fail to be possible on overlayfs mounts when the Yama LSM (out of tree)
is enabled. This module applies more aggressive checks on hard-links
preventing links to files you cannot read.
The bug seems to be related to the way we handle user and group owners for
the overlayfs inodes, which we do not initialise (and they remain as 0,0).
While these ownerships are never exposed to userspace they are exposed
to the LSM layer, and the LSM module checks the wrong owner and fails
to allow the links.
>From what I can see it is completly reasonable to initialise the ownership
fields in the overlayfs inode from the underlying inode, or for new files
ones initialise it in the normal way based on the containing directory.
Now I am nothing like a filesystems expert but looking at what other
filesystems do I think the patch below is sufficient, but certainly it
needs some sanity checking. At least it fixes all the issues I see here.
With this in place I have been able to boot a Natty release live CD
image, and upgrade it in place to the latest and greatest of everything.
Very nice. Thanks for your work continuing work on overlayfs. It is
starting to look good enough to merge.
Comments?
-apw
next prev parent reply other threads:[~2011-05-19 16:37 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-17 12:30 [PATCH 0/7] overlay filesystem v9 Miklos Szeredi
2011-05-17 12:30 ` [PATCH 1/7] tmpfs: implement generic xattr support Miklos Szeredi
2011-05-17 12:30 ` [PATCH 2/7] vfs: add i_op->open() Miklos Szeredi
2011-05-17 12:30 ` [PATCH 3/7] vfs: export do_splice_direct() to modules Miklos Szeredi
2011-05-17 12:30 ` [PATCH 4/7] vfs: introduce clone_private_mount() Miklos Szeredi
2011-05-17 12:30 ` [PATCH 5/7] overlay filesystem Miklos Szeredi
2011-05-17 12:30 ` [PATCH 6/7] overlayfs: add statfs support Miklos Szeredi
2011-05-17 12:30 ` [PATCH 7/7] overlay: overlay filesystem documentation Miklos Szeredi
2011-05-17 15:13 ` [PATCH 0/7] overlay filesystem v9 Michal Suchanek
2011-05-19 16:37 ` Andy Whitcroft [this message]
2011-05-19 17:44 ` Miklos Szeredi
2011-05-19 18:05 ` Andy Whitcroft
2011-05-19 22:12 ` NeilBrown
2011-05-20 8:18 ` Miklos Szeredi
2011-05-20 12:43 ` Andy Whitcroft
2011-05-19 19:04 ` John Stoffel
2011-05-19 20:30 ` Andy Whitcroft
2011-05-19 20:34 ` John Stoffel
2011-05-19 18:04 ` Andy Whitcroft
2011-05-20 8:56 ` Michal Suchanek
[not found] ` <103d3f78e2d3478d8bb93f5dda3a4a08@HUBCAS1.cs.stonybrook.edu>
2011-05-20 5:39 ` [PATCH 5/7] overlay filesystem (inode.c bad error path) Erez Zadok
2011-05-20 5:55 ` Erez Zadok
2011-05-20 14:25 ` Miklos Szeredi
[not found] ` <efad20cd4c664cd78e153b0fda2de605@HUBCAS2.cs.stonybrook.edu>
2011-05-21 5:15 ` Erez Zadok
2011-05-20 8:54 ` Miklos Szeredi
2011-05-20 14:17 ` Miklos Szeredi
[not found] ` <7dcd9c4e62864bc6aae66f5a4e3f3752@HUBCAS1.cs.stonybrook.edu>
2011-05-21 4:26 ` Erez Zadok
2011-05-21 4:26 ` Erez Zadok
2011-05-23 8:57 ` Miklos Szeredi
[not found] ` <b11ac28b818740a8b3f619e756735e41@HUBCAS2.cs.stonybrook.edu>
2011-05-24 1:02 ` Erez Zadok
2011-05-20 5:58 ` [PATCH 5/7] overlay filesystem (negative dentries cause OOPS on NULL inode) Erez Zadok
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