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Date:   Wed, 1 Apr 2020 12:05:53 -0700
From:   "Darrick J. Wong" <darrick.wong@oracle.com>
To:     Eric Biggers <ebiggers@kernel.org>
Cc:     David Howells <dhowells@redhat.com>, tytso@mit.edu,
        adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org
Subject: Re: Exporting ext4-specific information through fsinfo attributes
Message-ID: <20200401190553.GC56931@magnolia>
References: <2461554.1585726747@warthog.procyon.org.uk>
 <20200401162744.GB201933@gmail.com>
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On Wed, Apr 01, 2020 at 09:27:44AM -0700, Eric Biggers wrote:
> On Wed, Apr 01, 2020 at 08:39:07AM +0100, David Howells wrote:
> > Hi Ted,
> > 
> > Whilst we were at Vault, I asked you if there was any live ext4 information
> > that it could be useful to export through fsinfo().  I've implemented a patch
> > that exports six superblock timestamps:
> > 
> > 	FSINFO_ATTR_EXT4_TIMESTAMPS: 
> > 		mkfs    : 2016-02-26 00:37:03
> > 		mount   : 2020-03-31 21:57:30
> > 		write   : 2020-03-31 21:57:28
> > 		fsck    : 2018-12-17 23:32:45
> > 		1st-err : -
> > 		last-err: -
> > 
> > but is there anything else that could be of interest?
> > 
> > Thanks,
> > David
> > 
> 
> FWIW, the filesystem UUID would be useful for testing ext4 and f2fs encryption
> (since it's now sometimes used in the derivation of encryption keys).  But I see
> you already included it as FSINFO_ATTR_VOLUME_UUID.

It is??  What happens if you tune2fs -U if csum_seed isn't enabled?

--D

> 
> - Eric