NFSD: add support for NFSv4 write delegation
The NFSv4 server currently supports read delegation using VFS lease
which is implemented using file_lock.
This patch series add write delegation support for NFSv4 server by:
. remove the check for F_WRLCK in generic_add_lease to allow
file_lock to be used for write delegation.
. grant write delegation for OPEN with NFS4_SHARE_ACCESS_WRITE
if there is no conflict with other OPENs.
. add XDR support for sending and receiving CB_GETATTR.
. handle GETATTR from another client on a file that has outstanding
write delegation by using CB_GETATTR to get the latest change_info
and size for the GETATTR reply.
Write delegation conflict with another OPEN, REMOVE, RENAME and SETATTR
are handled the same as read delegation using notify_change, try_break_deleg.
Changes since v1:
[PATCH 3/4] NFSD: add supports for CB_GETATTR callback
- remove WARN_ON_ONCE from encode_bitmap4
- replace decode_bitmap4 with xdr_stream_decode_uint32_array
- replace xdr_inline_decode and xdr_decode_hyper in decode_cb_getattr
with xdr_stream_decode_u64. Also remove the un-needed likely().
- modify signature of encode_cb_getattr4args to take pointer to
nfs4_cb_fattr
- replace decode_attr_length with xdr_stream_decode_u32
- rename decode_cb_getattr to decode_cb_fattr4
- fold the initialization of cb_cinfo and cb_fsize into decode_cb_fattr4
- rename ncf_cb_cinfo to ncf_cb_change to avoid confusion of cindo usage
in fs/nfsd/nfs4xdr.c
- correct NFS4_dec_cb_getattr_sz and update size description
[PATCH 4/4] NFSD: handle GETATTR conflict with write delegation
- change nfs4_handle_wrdeleg_conflict returns __be32 to fix test robot
- change ncf_cb_cinfo to ncf_cb_change to avoid confusion of cindo usage
in fs/nfsd/nfs4xdr.c
