From: Christoph Hellwig <hch@lst.de>
To: "André Almeida" <andrealmeid@igalia.com>
Cc: Amir Goldstein <amir73il@gmail.com>,
Christoph Hellwig <hch@lst.de>,
Chuck Lever <chuck.lever@oracle.com>,
Jeff Layton <jlayton@kernel.org>, NeilBrown <neil@brown.name>,
Olga Kornievskaia <okorniev@redhat.com>,
Dai Ngo <Dai.Ngo@oracle.com>, Tom Talpey <tom@talpey.com>,
Carlos Maiolino <cem@kernel.org>, Chris Mason <clm@fb.com>,
David Sterba <dsterba@suse.com>,
Miklos Szeredi <miklos@szeredi.hu>,
Christian Brauner <brauner@kernel.org>,
Alexander Viro <viro@zeniv.linux.org.uk>, Jan Kara <jack@suse.cz>,
linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
Qu Wenruo <wqu@suse.com>,
linux-btrfs@vger.kernel.org, linux-unionfs@vger.kernel.org,
kernel-dev@igalia.com
Subject: Re: [PATCH 3/3] ovl: Use real disk UUID for origin file handles
Date: Fri, 16 Jan 2026 10:36:43 +0100 [thread overview]
Message-ID: <20260116093643.GA23235@lst.de> (raw)
In-Reply-To: <0241e2c4-bf11-4372-9eda-cccaba4a6d7d@igalia.com>
On Thu, Jan 15, 2026 at 03:55:15PM -0300, André Almeida wrote:
>> Is there any guarantee that file handles are relevant and point to the
>> same objects?
>>
>> The whole point of the overlayfs index feature is that overlayfs inodes
>> can have a unique id across copy-up.
>>
>> Please explain in more details exactly which overlayfs setup you are
>> trying to do with index feature.
>>
>
> The problem happens _before_ switching from A to B, it happens when trying
> to install the same image from A on B.
>
> During the image installation process, while running in A, the B image will
> be mounted more than once for some setup steps, and overlayfs is used for
> this. Because A have the same UUID, each time B is remouted will get a new
> UUID and then the installation scripts fails mounting the image.
It sounds like the 'clones' really need different persistent uuids. Or
do you also have a requirement that the two images have the same ID,
which would require a noouid-like option and extremely careful handling.
next prev parent reply other threads:[~2026-01-16 9:36 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-14 4:31 [PATCH 0/3] fs: Support btrfs cloned images and overlayfs André Almeida
2026-01-14 4:31 ` [PATCH 1/3] exportfs: Rename get_uuid() to get_disk_uuid() André Almeida
2026-01-14 6:10 ` Darrick J. Wong
2026-01-14 6:24 ` Christoph Hellwig
2026-01-14 10:12 ` Amir Goldstein
2026-01-14 13:11 ` Christoph Hellwig
2026-01-14 16:38 ` André Almeida
2026-01-14 17:58 ` Amir Goldstein
2026-01-14 4:31 ` [PATCH 2/3] btrfs: Implement get_disk_uuid() André Almeida
2026-01-14 4:31 ` [PATCH 3/3] ovl: Use real disk UUID for origin file handles André Almeida
2026-01-14 6:26 ` Christoph Hellwig
2026-01-14 16:17 ` André Almeida
2026-01-15 6:29 ` Christoph Hellwig
2026-01-15 6:51 ` Qu Wenruo
2026-01-15 7:23 ` Christoph Hellwig
2026-01-15 8:09 ` Qu Wenruo
2026-01-15 8:31 ` Christoph Hellwig
2026-01-15 15:42 ` André Almeida
2026-01-15 16:07 ` Amir Goldstein
2026-01-15 18:55 ` André Almeida
2026-01-16 9:36 ` Christoph Hellwig [this message]
2026-01-16 9:55 ` Amir Goldstein
2026-01-16 13:27 ` André Almeida
2026-01-16 17:06 ` Amir Goldstein
2026-01-19 16:56 ` André Almeida
2026-01-20 15:12 ` Amir Goldstein
2026-01-22 20:07 ` Amir Goldstein
2026-01-23 13:24 ` André Almeida
2026-01-23 20:08 ` André Almeida
2026-01-24 10:45 ` Amir Goldstein
2026-01-28 11:49 ` Amir Goldstein
2026-02-05 20:34 ` André Almeida
2026-02-06 13:12 ` Amir Goldstein
2026-02-16 14:59 ` André Almeida
2026-02-17 13:26 ` Amir Goldstein
2026-01-15 16:08 ` Christoph Hellwig
2026-01-14 17:54 ` Amir Goldstein
2026-01-15 6:36 ` Christoph Hellwig
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