On Mon, Jun 24, 2024 at 11:17 AM Trond Myklebust
<trondmy@xxxxxxxxxxxxxxx> wrote:
>
> Hi Olga,
>
> On Mon, 2024-06-24 at 09:28 -0400, Olga Kornievskaia wrote:
> > From: Olga Kornievskaia <kolga@xxxxxxxxxx>
> >
> > Previously in order to mark the communication with the DS server,
> > we tried to use NFS_CS_DS in cl_flags. However, this flag would
> > only be saved for the DS server and in case where DS equals MDS,
> > the client would not find a matching nfs_client in nfs_match_client
> > that represents the MDS (but is also a DS).
> >
> > Instead, don't rely on the NFS_CS_DS but instead use NFS_CS_PNFS.
> >
> > Fixes: 379e4adfddd6 ("NFSv4.1: fixup use EXCHGID4_FLAG_USE_PNFS_DS
> > for DS server")
> > Signed-off-by: Olga Kornievskaia <kolga@xxxxxxxxxx>
> > ---
> > fs/nfs/nfs4client.c | 6 ++----
> > fs/nfs/nfs4proc.c | 2 +-
> > 2 files changed, 3 insertions(+), 5 deletions(-)
> >
> > diff --git a/fs/nfs/nfs4client.c b/fs/nfs/nfs4client.c
> > index 11e3a285594c..ac80f87cb9d9 100644
> > --- a/fs/nfs/nfs4client.c
> > +++ b/fs/nfs/nfs4client.c
> > @@ -231,9 +231,8 @@ struct nfs_client *nfs4_alloc_client(const struct
> > nfs_client_initdata *cl_init)
> > __set_bit(NFS_CS_INFINITE_SLOTS, &clp->cl_flags);
> > __set_bit(NFS_CS_DISCRTRY, &clp->cl_flags);
> > __set_bit(NFS_CS_NO_RETRANS_TIMEOUT, &clp->cl_flags);
> > -
> > - if (test_bit(NFS_CS_DS, &cl_init->init_flags))
> > - __set_bit(NFS_CS_DS, &clp->cl_flags);
> > + if (test_bit(NFS_CS_PNFS, &cl_init->init_flags))
> > + __set_bit(NFS_CS_PNFS, &clp->cl_flags);
>
> Won't this change cause the match in nfs_get_client() to fail?
At which stage? The problem was that nfs_match_client explicitly looks
for NFS_CS_DS for matching.
/* Match request for a dedicated DS */
if (test_bit(NFS_CS_DS, &data->init_flags) !=
test_bit(NFS_CS_DS, &clp->cl_flags))
continue;
We have pnfs flow creating client where NFS_CS_DS was set in
init_flags and yet the stored nfs_client didn't because we dont mark
the MDS exchange_id with DS flags.
In my testing the fixed way appropriately finds the MDS's nfs_client
for when MDS=DS and for when it's not there isn't one to begin with
but we still only mark USE_PNFS_DS on the pnfs path and not 4.1 mount.
>
>
>
> --
> Trond Myklebust
> Linux NFS client maintainer, Hammerspace
> trond.myklebust@xxxxxxxxxxxxxxx
>
>
