On Fri, Jan 14, 2011 at 02:45:56PM +0800, Fu Liankun wrote:
> The RFC3530 describes that the client's all lock operations, including those
> requesting non-exclusive locks, should be sent to the server for resolution,
> even if it holds a read open delegation. But the kernel implements like that
> lock operations can be performed locally when a client holds an open
> delegation.
>
> The following are the RFC3530 provisions for Open Delegation and File Locks:
>
> 9.4.2. Open Delegation and File Locks
>
> When a client holds a write open delegation, lock operations may be
> performed locally. This includes those required for mandatory file
> locking. This can be done since the delegation implies that there
> can be no conflicting locks. Similarly, all of the revalidations
> that would normally be associated with obtaining locks and the
> flushing of data associated with the releasing of locks need not be
> done.
>
> When a client holds a read open delegation, lock operations are not
> performed locally. All lock operations, including those requesting
> non-exclusive locks, are sent to the server for resolution.
Weird. Can the rfc really be right about that?
I guess it does permit servers to allow write-locks on read-open files,
but it seems bizarre not to require them to break delegations in that
case.
--b.
>
> Signed-off-by: Fu Liankun <fuliankun@xxxxxxxxxxxxxx>
> ---
> fs/nfs/nfs4proc.c | 7 -------
> 1 files changed, 0 insertions(+), 7 deletions(-)
>
> diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
> index 0f24cdf..3bba85b 100644
> --- a/fs/nfs/nfs4proc.c
> +++ b/fs/nfs/nfs4proc.c
> @@ -4215,13 +4215,6 @@ static int _nfs4_proc_setlk(struct nfs4_state *state, int cmd, struct file_lock
> if (status < 0)
> goto out;
> down_read(&nfsi->rwsem);
> - if (test_bit(NFS_DELEGATED_STATE, &state->flags)) {
> - /* Yes: cache locks! */
> - /* ...but avoid races with delegation recall... */
> - request->fl_flags = fl_flags & ~FL_SLEEP;
> - status = do_vfs_lock(request->fl_file, request);
> - goto out_unlock;
> - }
> status = _nfs4_do_setlk(state, cmd, request, NFS_LOCK_NEW);
> if (status != 0)
> goto out_unlock;
> --
> 1.7.3.1
>
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