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From: "J. R. Okajima" <hooanon05@yahoo.co.jp>
To: Miklos Szeredi <miklos@szeredi.hu>
Cc: viro@ZenIV.linux.org.uk, linux-fsdevel@vger.kernel.org,
	linux-kernel@vger.kernel.org, apw@canonical.com, nbd@openwrt.org,
	neilb@suse.de, hramrach@centrum.cz,
	Miklos Szeredi <mszeredi@suse.cz>
Subject: Re: [PATCH 6/6] overlay: overlay filesystem documentation
Date: Tue, 19 Apr 2011 12:05:17 +0900	[thread overview]
Message-ID: <7795.1303182317@jrobl> (raw)
In-Reply-To: <1303142440-26328-7-git-send-email-miklos@szeredi.hu>


Hello Miklos,

Miklos Szeredi:
> +The lower filesystem can be any filesystem supported by Linux and does
> +not need to be writable.  The lower filesystem can even be another
> +overlayfs.  ...

When user mounts overlayfs over and over like this,
# mount -t overlayfs -o upper=/rw1,lower=/ro1 none /ovl1
# mount -t overlayfs -o upper=/rw2,lower=/ovl1 none /ovl2
	:::
# mount -t overlayfs -o upper=/rwN,lower=/ovl{N-1} none /ovlN

And if he modify a file in the bottom RO layer, then overlayfs copies-up
the file into each RW layer?
- 'fileA' exists in only /ro1.
- nested mounts.
- run "echo append >> /ovlN/fileA"
- is fileA copied-up to /rw1, and then to /rw2, and then ... to /rwN?

If user specify a single dir as every upper laery, then the copyup will
be done only once, or such RW layers are not allowed?


J. R. Okajima

  reply	other threads:[~2011-04-19  3:05 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-04-18 16:00 [PATCH 0/6] overlay filesystem Miklos Szeredi
2011-04-18 16:00 ` [PATCH 1/6] vfs: add i_op->open() Miklos Szeredi
2011-04-18 16:00 ` [PATCH 2/6] vfs: export do_splice_direct() to modules Miklos Szeredi
2011-04-18 16:00 ` [PATCH 3/6] vfs: introduce clone_private_mount() Miklos Szeredi
2011-04-18 16:00 ` [PATCH 4/6] overlay filesystem Miklos Szeredi
2011-04-18 16:00 ` [PATCH 5/6] overlayfs: add statfs support Miklos Szeredi
2011-04-18 16:00 ` [PATCH 6/6] overlay: overlay filesystem documentation Miklos Szeredi
2011-04-19  3:05   ` J. R. Okajima [this message]
2011-04-19  3:58     ` NeilBrown
2011-04-19  4:13       ` J. R. Okajima
2011-04-18 18:19 ` [PATCH 0/6] overlay filesystem Michal Suchanek
2011-04-19  9:39   ` Miklos Szeredi
2011-04-19  9:43     ` [PATCH 1/2] ovl: fix missing include Miklos Szeredi
2011-04-19  9:43     ` [PATCH 2/2] ovl: fix building as a module Miklos Szeredi
2011-05-09 19:14 ` [PATCH 0/6] overlay filesystem Michal Suchanek
2011-05-10 16:30   ` Miklos Szeredi
  -- strict thread matches above, loose matches on Subject: below --
2010-09-03 13:41 [PATCH 0/6] overlay filesystem prototype Miklos Szeredi
2010-09-03 13:41 ` [PATCH 6/6] overlay: overlay filesystem documentation Miklos Szeredi

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