----- Original Message ----- > From: "Jeuk Kim" > To: "Trond Myklebust" , "Anna Schumaker" > Cc: "linux-nfs" , "linux-kernel" , "Tigran Mkrtchyan" > , "hui81 qi" , "j-young choi" , "peng yun" > , "qian01 li" , "xing1 he" , "jeuk20 kim" > > Sent: Wednesday, 8 July, 2026 09:44:31 > Subject: [PATCH 0/2] NFSv4/flexfiles: support loosely coupled data servers > RFC 8435 allows a flexfiles data server to be loosely coupled, i.e. an > NFS server that does not advertise EXCHGID4_FLAG_USE_PNFS_DS via > EXCHANGE_ID. The client currently ignores the ffdv_tightly_coupled flag > and treats every DS as tightly coupled, so NFSv4.1+ I/O to a loosely > coupled DS fails during DS setup. > > Patch 2 threads the decoded tightly_coupled flag down to the DS connect > path and, when it is false, skips the NFS_CS_PNFS flag and the > is_ds_client() check. > > Patch 1 fixes pre-existing NFSv4.0 DS crashes on the same path (the DS > client has no session). > > Jeuk Kim (2): > NFSv4/flexfiles: fix NULL dereference for NFSv4.0 data servers > NFSv4/flexfiles: support loosely coupled data servers > > fs/nfs/filelayout/filelayoutdev.c | 2 +- > fs/nfs/flexfilelayout/flexfilelayout.c | 3 ++- > fs/nfs/flexfilelayout/flexfilelayoutdev.c | 3 ++- > fs/nfs/internal.h | 3 ++- > fs/nfs/nfs4client.c | 5 +++-- > fs/nfs/nfs4session.c | 21 ++++++++++++++------- > fs/nfs/nfs4session.h | 3 ++- > fs/nfs/pnfs.h | 3 ++- > fs/nfs/pnfs_nfs.c | 14 +++++++++----- > 9 files changed, 37 insertions(+), 20 deletions(-) > > -- > 2.43.0 Just checked that the tightly coupled servers configuration is still ok. Tested-by: "Tigran Mkrtchyan"