From: Christoph Hellwig <hch@infradead.org>
To: Anand Jain <anajain.sg@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>,
Theodore Tso <tytso@mit.edu>,
"Darrick J. Wong" <djwong@kernel.org>,
linux-ext4@vger.kernel.org, linux-btrfs@vger.kernel.org,
linux-xfs@vger.kernel.org, Anand Jain <asj@kernel.org>,
dsterba@suse.com
Subject: Re: [PATCH v2 3/3] ext4: derive f_fsid from block device to avoid collisions
Date: Wed, 22 Apr 2026 22:08:29 -0700 [thread overview]
Message-ID: <aempTb5TyKG0vPL0@infradead.org> (raw)
In-Reply-To: <cd9c0147-18cf-464d-86e2-12342a992ebc@gmail.com>
On Wed, Apr 22, 2026 at 07:39:57PM +0800, Anand Jain wrote:
> > No, T10 does not actually mandate unique identifiers, NVMe does, but the
> > implementations are often totally broken.
>
> Right. Newer SPC-3 (and above) compliant devices must support
> the Inquiry CDB EVPD flag and provide page 0x83 for identification,
> which is what we typically use for multipathing.
But there is no requirement for it to contain something useful.
> These are globally unique. And, we can overlook legacy
> drives, as they've probably been past their EOSL for a while now.
We have absolutely no useful identifiers for most USB devices.
NVMe devices have broken identifiers all the time as well.
So no, you can't.
prev parent reply other threads:[~2026-04-23 5:08 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-21 11:55 [PATCH v2 0/3] fix s_uuid and f_fsid consistency for cloned filesystems Anand Jain
2026-03-21 11:55 ` [PATCH v2 1/3] btrfs: use on-disk uuid for s_uuid in temp_fsid mounts Anand Jain
2026-03-21 11:55 ` [PATCH v2 2/3] btrfs: derive f_fsid from on-disk fsuuid and dev_t Anand Jain
2026-03-21 11:55 ` [PATCH v2 3/3] ext4: derive f_fsid from block device to avoid collisions Anand Jain
2026-03-23 4:16 ` Theodore Tso
2026-03-23 15:29 ` Darrick J. Wong
2026-03-23 16:44 ` Darrick J. Wong
2026-03-25 10:02 ` Andreas Dilger
2026-03-25 10:59 ` Anand Jain
2026-03-25 12:59 ` Theodore Tso
2026-04-02 7:33 ` Anand Jain
2026-03-23 15:41 ` Anand Jain
2026-04-04 8:59 ` Anand Jain
2026-04-07 5:22 ` Christoph Hellwig
2026-04-07 14:47 ` Theodore Tso
2026-04-08 22:28 ` Anand Jain
2026-04-09 4:10 ` Theodore Tso
2026-04-09 9:45 ` Anand Jain
2026-04-09 13:12 ` Theodore Tso
2026-04-16 15:21 ` Anand Jain
2026-04-17 7:34 ` Christoph Hellwig
2026-04-22 11:39 ` Anand Jain
2026-04-23 5:08 ` Christoph Hellwig [this message]
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