FSRVP snapshot set failed

[David Disseldorp]

Hi Dennis,

On Tue, 25 Jun 2013 12:56:14 +0800
Teng-Feng Yang <shinrairis at gmail.com> wrote:

> Hi,
> 
> As I do more research on the FSRVP implemented by David recently, now
> I am be able to take snapshots of both btrfs and dm-thin volumes
> remotely. However, when I am trying to create a snapshot set with
> multiple volumes and take snapshot of this set, it fails unexpectedly.
> The following are the steps I take to create and take snapshot on a
> snapshot set.
> 
> In Windows server 2012, I have joined the AD domain and be able to
> create single snapshot on each share volume.
> diskshadow> set context persistent
> diskshadow> add volume \\<samba server with FSRVP support>\<share volume 1>
> diskshadow> add volume \\<samba server with FSRVP support>\<share volume 2>
> diskshadow> create
> 
> The "create" command will return the error message:
> COM call "m_pVssBackup->AddToSnapshotSet" failed.
> The last operation failed.
>     - Returned HRESULT: 8004230c
>     - Error text: VSS_E_VOLUME_NOT_SUPPORTED
> 
> I check the samba log to see how samba process the "create" command.
> It turns out that diskshadow.exe will call the following rpc api:
> FSS_GETSUPPORTEDVERSION -> FSS_SETCONTEXT -> FSS_STARTSHADOWCOPYSET ->
> FSS_ADDTOSHADOWCOPYSET-> FSS_ISPATHSUPPORTED. I don't really sure if
> this is a correct rpc calling sequence, for I think there should be
> another FSS_ADDTOSHADOWCOPYSET call instead of FSS_ISPATHSUPPORTED
> which already been called when we issue "add volume" command in the
> diskshadow utility.

Interesting, that sequence differs from how rpcclient fss_create_expose
handles multi-share shadow-copy requests. Please provide a network
trace, as I'd like to add a corresponding smbtorture test.

> The actual error message in the log file is:
> 
> /usr/local/samba/sbin/smbd: Requested \FssagentRpc rpc service
> /usr/local/samba/sbin/smbd: api_rpcTNP: \FssagentRpc op 0x8 -
> api_rpcTNP: rpc command: FSS_ISPATHSUPPORTED
> /usr/local/samba/sbin/smbd: api_rpc_cmds[8].fn_send == 0x7f183cd2a5e9
> /usr/local/samba/sbin/smbd: ndr_pull_error(11): Pull bytes 52
> (../librpc/ndr/ndr_basic.c:420)
> /usr/local/samba/sbin/smbd: pop_sec_ctx (0, 0) - sec_ctx_stack_ndx = 0
> /usr/local/samba/sbin/smbd: api_rpcTNP: \FssagentRpc:
> FSS_ISPATHSUPPORTED failed.

Is there anything in the snapper log?

Regards, David