[PATCH v2 0/4] NFSD: add support for NFSv4 write delegation

From: Dai Ngo <dai.ngo@oracle.com>
To: chuck.lever@oracle.com, jlayton@kernel.org
Cc: linux-nfs@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: [PATCH v2 0/4] NFSD: add support for NFSv4 write delegation
Date: Sun, 14 May 2023 17:20:34 -0700	[thread overview]
Message-ID: <1684110038-11266-1-git-send-email-dai.ngo@oracle.com> (raw)

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