Re: [bug report] Inconsistent state with CIFS mount after interrupted process in Linux 5.10

["Aurélien Aptel" <aaptel@suse.com>]

Duncan Findlay <duncf@duncf.ca> writes:
> There seems to be a problem with the CIFS module in Linux 5.10. Files
> that are opened and not cleanly closed end up in an inconsistent
> state. This can be triggered by writing to a file and interrupting the
> writer with Ctrl-C. Once this happens, attempting to delete the file
> causes access to the mount to hang. Afterwards, the files are visible
> to ls, but cannot be accessed or deleted.
>
> I'm running Debian unstable with a Debian unstable kernel
> (5.10.5-1). I attempted to but could not reproduce this with a 4.19 kernel.
>
>
> Repro steps:
>
> $ sudo mount -t cifs //test/share /mnt/test --verbose -o
> rw,user,auto,nosuid,uid=user,gid=user,vers=3.1.1,credentials=/home/user/tmp/creds
> $ mkdir /mnt/test/subdir
> $ cat > /mnt/test/subdir/foo
> [ Hit Ctrl-C to interrupt ]
> $ ls /mnt/test/subdir/
> foo
> $ rm /mnt/test/subdir/foo
> [ Hangs for 35 seconds, errors in dmesg log -- see below ]
> $ ls /mnt/test/subdir/
> foo
> $ stat /mnt/test/subdir/foo
> stat: cannot statx '/mnt/test/subdir/foo': No such file or directory
>
> At this point, the file still exists on the server side, and
> restarting the server causes it to be deleted.
>
> I can provide pcaps if necessary. It looks like with 4.19, when the
> cat command is killed, the client sends a Close Request, and on 5.10
> no commands are sent.

I can reproduce this on Steve's current for-next branch but only against
a Samba server.

On Windows server, doing ^C kills cat properly but the output file is
never created, which is also a bug.

Cheers,
-- 
Aurélien Aptel / SUSE Labs Samba Team
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