From mboxrd@z Thu Jan  1 00:00:00 1970
From: Edward Shishkin <edward.shishkin@gmail.com>
Subject: Re: Occasionally mkfs.reiser4 creates a file system without a UUID
Date: Sat, 13 Mar 2021 12:37:44 +0100
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To: Mike Fleetwood <mike.fleetwood@googlemail.com>, reiserfs-devel@vger.kernel.org

On 03/12/2021 08:36 PM, Mike Fleetwood wrote:
> Hi,
> 
> Occasionally mkfs.reiser4 creates a file system without a UUID,
> debugfs.reiser4 reports UUID as '<none>'.  This is being detected in
> GParted's file system interface CI tests [1] which exercises the resier4
> commands.
> 
> In a Ubuntu 20.04 LTS VM with both resier4progs-1.2.1-1 package and
> current code from GIT, the fault can easily be replicated like this:
> 
> truncate -s 256M test.img
> i=1
> while :
> do
>    mkfs.reiser4 --force --yes --label '' test.img
>    line=`debugfs.reiser4 test.img 2> /dev/null | egrep '^uuid:'`
>    echo "[$i] $line"
>    ((i++))
>    echo "$line" | grep -q '<none>' && break
> done
> 
> Output fragment:
> [1] uuid:        17073919-e41d-4892-9b22-4294d1544c4a
> [2] uuid:        af2821de-ea85-4f20-9621-4fbd128b3fb8
> [3] uuid:        c0fb805b-e224-4695-a504-d87460d158ae
> ...
> [35] uuid:        d604794d-097f-4810-bbb3-01a1518f3ef1
> [36] uuid:        9634100c-1f98-42b3-a684-c9df77ab54e2
> [37] uuid:        <none>
> 
> Performing the same test with resierfs and ext4 runs for many hours
> doing 100,000s of iterations without issue.
> 


It seems that debugfs.reiser4 prints uuid incorrectly: it assumes that
binary uuid can't contain '\0' symbols, which apparently is wrong.
Thus, if the first uuid's symbol is '\0', debugfs thinks that uuid is
not set and prints "none" ;)

I'll try to prepare a fixup a bit later.
Special thanks for the nice testing script!

Edward.


> Thanks,
> Mike
> 
> [1] Sporadic failure of test case
> My/SupportedFileSystemsTest.CreateAndReadUUID/reiser4
>      https://gitlab.gnome.org/GNOME/gparted/-/issues/145
>