From: Anand Jain <anajain.sg@gmail.com>
To: "Christoph Hellwig" <hch@infradead.org>,
"André Almeida" <andrealmeid@igalia.com>
Cc: linux-kernel@vger.kernel.org, linux-btrfs@vger.kernel.org,
linux-unionfs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
kernel-dev@igalia.com, Miklos Szeredi <miklos@szeredi.hu>,
Amir Goldstein <amir73il@gmail.com>, Chris Mason <clm@fb.com>,
David Sterba <dsterba@suse.com>,
"Guilherme G . Piccoli" <gpiccoli@igalia.com>
Subject: Re: [RFC PATCH 1/1] ovl: Use fsid as unique identifier for trusted origin
Date: Wed, 15 Oct 2025 07:46:34 +0800 [thread overview]
Message-ID: <5137ce36-c3b4-4a0a-83af-e00892feaf43@gmail.com> (raw)
In-Reply-To: <aO3T8BGM6djYFyrz@infradead.org>
On 14-Oct-25 12:39 PM, Christoph Hellwig wrote:
> On Mon, Oct 13, 2025 at 10:57:07PM -0300, André Almeida wrote:
>> Some filesystem have non-persistent UUIDs, that can change between
>> mounting, even if the filesystem is not modified. To prevent
>> false-positives when mounting overlayfs with index enabled, use the fsid
>> reported from statfs that is persistent across mounts.
>
> Please fix btrfs to not change uuids, as that completely defeats the
> point of uuids.
We needed cloned device mount support for an A/B testing
use case, but changing the on-disk UUID defeats the purpose.
Right now, ext4 and Btrfs can mount identical devices,
but XFS can't. How about extending this to the common
VFS layer and adding a parameter to tell apart a cloned
device from the same device accessed through multiple
paths? I haven't looked into the details yet, but I can
dig it further.
next prev parent reply other threads:[~2025-10-14 23:46 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-14 1:57 [RFC PATCH 0/1] ovl: brtfs' temp_fsid doesn't work with ovl index=on André Almeida
2025-10-14 1:57 ` [RFC PATCH 1/1] ovl: Use fsid as unique identifier for trusted origin André Almeida
2025-10-14 4:39 ` Christoph Hellwig
2025-10-14 5:13 ` Qu Wenruo
2025-10-14 17:40 ` David Sterba
2025-10-14 17:55 ` André Almeida
2025-10-14 23:46 ` Anand Jain [this message]
2025-10-15 1:22 ` Christoph Hellwig
2025-10-20 21:43 ` Dave Chinner
2025-10-21 1:16 ` Anand Jain
2025-10-14 19:52 ` kernel test robot
2025-10-15 10:52 ` Amir Goldstein
2025-10-14 5:26 ` [RFC PATCH 0/1] ovl: brtfs' temp_fsid doesn't work with ovl index=on Qu Wenruo
2025-10-14 18:24 ` David Sterba
2025-10-14 21:08 ` Qu Wenruo
2025-10-15 0:05 ` Anand Jain
2025-10-15 4:18 ` Qu Wenruo
2025-10-14 22:04 ` Anand Jain
2025-10-15 11:09 ` Amir Goldstein
2025-10-16 4:57 ` Christoph Hellwig
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