On Fri, Jan 2, 2015 at 4:44 PM, Chuck Lever <chuck.lever@xxxxxxxxxx> wrote:
>
> On Jan 2, 2015, at 4:39 PM, Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx> wrote:
>
>> Currently, our trunking code will check for session trunking, but will
>> fail to detect client id trunking. This is a problem, because it means
>> that the client will fail to recognise that the two connections represent
>> shared state, even if they do not permit a shared session.
>> By removing the check for the server minor id, and only checking the
>> major id, we will end up doing the right thing in both cases: we close
>> down the new nfs_client and fall back to using the existing one.
>
> Fair enough.
>
> Does this detect the case where two concurrent NFSv4.1 mounts
> of the same server use different transport protocols?
I'm not sure I understand what you mean. The client should completely
ignore the transport protocol when doing trunking detection. The only
thing that it cares about is whether or not the server believes we
should be sharing state, in which case the client should fall back to
using the existing connection for the new mount point.
>> Fixes: 05f4c350ee02e ("NFS: Discover NFSv4 server trunking when mounting")
>> Cc: Chuck Lever <chuck.lever@xxxxxxxxxx>
>> Cc: stable@xxxxxxxxxxxxxxx # 3.7.x
>> Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
>> ---
>> fs/nfs/nfs4client.c | 17 ++++++++---------
>> 1 file changed, 8 insertions(+), 9 deletions(-)
>>
>> diff --git a/fs/nfs/nfs4client.c b/fs/nfs/nfs4client.c
>> index 03311259b0c4..d949d0f378ec 100644
>> --- a/fs/nfs/nfs4client.c
>> +++ b/fs/nfs/nfs4client.c
>> @@ -566,20 +566,14 @@ static bool nfs4_match_clientids(struct nfs_client *a, struct nfs_client *b)
>> }
>>
>> /*
>> - * Returns true if the server owners match
>> + * Returns true if the server major ids match
>> */
>> static bool
>> -nfs4_match_serverowners(struct nfs_client *a, struct nfs_client *b)
>> +nfs4_check_clientid_trunking(struct nfs_client *a, struct nfs_client *b)
>> {
>> struct nfs41_server_owner *o1 = a->cl_serverowner;
>> struct nfs41_server_owner *o2 = b->cl_serverowner;
>>
>> - if (o1->minor_id != o2->minor_id) {
>> - dprintk("NFS: --> %s server owner minor IDs do not match\n",
>> - __func__);
>> - return false;
>> - }
>> -
>> if (o1->major_id_sz != o2->major_id_sz)
>> goto out_major_mismatch;
>> if (memcmp(o1->major_id, o2->major_id, o1->major_id_sz) != 0)
>> @@ -654,7 +648,12 @@ int nfs41_walk_client_list(struct nfs_client *new,
>> if (!nfs4_match_clientids(pos, new))
>> continue;
>>
>> - if (!nfs4_match_serverowners(pos, new))
>> + /*
>> + * Note that session trunking is just a special subcase of
>> + * client id trunking. In either case, we want to fall back
>> + * to using the existing nfs_client.
>> + */
>> + if (!nfs4_check_clientid_trunking(pos, new))
>> continue;
>>
>> atomic_inc(&pos->cl_count);
>> --
>> 2.1.0
>>
>
> --
> Chuck Lever
> chuck[dot]lever[at]oracle[dot]com
>
>
>
--
Trond Myklebust
Linux NFS client maintainer, PrimaryData
trond.myklebust@xxxxxxxxxxxxxxx
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