On Fri, Nov 18, 2016 at 9:32 AM, Trond Myklebust
<trondmy@xxxxxxxxxxxxxxx> wrote:
>
>> On Nov 18, 2016, at 00:01, NeilBrown <neilb@xxxxxxxx> wrote:
>>
>>
>> Ping?
>> No sign of this in linux-next, and no replies….
>
> I’d like some confirmation from the NetApp folks on this. They are the main stakeholders for the pNFS files implementation. I don’t think we need an equivalent for flex files.
Just to see if I understand this patch. If "ds" isn't NULL, then the
client has an RPC client with the ds. But it doesn't have a valid NFS
client? Looking at the code I really don't see how that can happen.
Maybe there is a bug elsewhere? If we return here, is there a chance
we are going to have a zombie RPC client with the ds? If that's not a
problem then I don't think there an issue to assume that if there is
no valid NFS client then we would want to return a NULL from
nfs4_fl_prepare_ds().
>
>>
>> Thanks,
>> NeilBrown
>>
>>
>> On Fri, Oct 21 2016, NeilBrown wrote:
>>
>>>
>>> Various places assume that if nfs4_fl_prepare_ds() turns a non-NULL
>>> 'ds', then ds->ds_clp will also be non-NULL.
>>>
>>> This is not necessasrily true in the case when the process received a
>>> fatal signal while nfs4_pnfs_ds_connect is waiting in
>>> nfs4_wait_ds_connect(). In that case ->ds_clp may not be set, and the
>>> devid may not recently have been marked unavailable.
>>>
>>> So add a test for ->ds_clp == NULL and return NULL in that case.
>>>
>>> Fixes: c23266d532b4 ("NFS4.1 Fix data server connection race")
>>> Signed-off-by: NeilBrown <neilb@xxxxxxxx>
>>> ---
>>> fs/nfs/filelayout/filelayoutdev.c | 3 ++-
>>> 1 file changed, 2 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/fs/nfs/filelayout/filelayoutdev.c b/fs/nfs/filelayout/filelayoutdev.c
>>> index 4946ef40ba87..85ef38f9765f 100644
>>> --- a/fs/nfs/filelayout/filelayoutdev.c
>>> +++ b/fs/nfs/filelayout/filelayoutdev.c
>>> @@ -283,7 +283,8 @@ nfs4_fl_prepare_ds(struct pnfs_layout_segment *lseg, u32 ds_idx)
>>> s->nfs_client->cl_rpcclient->cl_auth->au_flavor);
>>>
>>> out_test_devid:
>>> - if (filelayout_test_devid_unavailable(devid))
>>> + if (ret->ds_clp == NULL ||
>>> + filelayout_test_devid_unavailable(devid))
>>> ret = NULL;
>>> out:
>>> return ret;
>>> --
>>> 2.10.1
>
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