nfsd: implement OPEN_ARGS_SHARE_ACCESS_WANT_OPEN_XOR_DELEGATION

Allow clients to request getting a delegation xor an open stateid if a
delegation isn't available. This allows the client to avoid sending a
final CLOSE for the (useless) open stateid, when it is granted a
delegation.

If this flag is requested by the client and there isn't already a new
open stateid, discard the new open stateid before replying.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index ab19ac7b232912d495f2af212a0ba24eff8b7ecc..b7a0cfd05401d406412119b3b8acf5d4fc020262 100644 (file)
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -6242,6 +6242,17 @@ static void nfsd4_deleg_xgrade_none_ext(struct nfsd4_open *open,
         */
 }
 
+/* Are we returning only a delegation stateid? */
+static bool open_xor_delegation(struct nfsd4_open *open)
+{
+       if (!(open->op_deleg_want & OPEN4_SHARE_ACCESS_WANT_OPEN_XOR_DELEGATION))
+               return false;
+       /* Did we actually get a delegation? */
+       if (!deleg_is_read(open->op_delegate_type) && !deleg_is_write(open->op_delegate_type))
+               return false;
+       return true;
+}
+
 /**
  * nfsd4_process_open2 - finish open processing
  * @rqstp: the RPC transaction being executed
@@ -6339,6 +6350,17 @@ nfsd4_process_open2(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nf
        * OPEN succeeds even if we fail.
        */
        nfs4_open_delegation(open, stp, &resp->cstate.current_fh);
+
+       /*
+        * If there is an existing open stateid, it must be updated and
+        * returned. Only respect WANT_OPEN_XOR_DELEGATION when a new
+        * open stateid would have to be created.
+        */
+       if (new_stp && open_xor_delegation(open)) {
+               memcpy(&open->op_stateid, &zero_stateid, sizeof(open->op_stateid));
+               open->op_rflags |= OPEN4_RESULT_NO_OPEN_STATEID;
+               release_open_stateid(stp);
+       }
 nodeleg:
        status = nfs_ok;
        trace_nfsd_open(&stp->st_stid.sc_stateid);
@@ -6355,7 +6377,7 @@ out:
        /*
        * To finish the open response, we just need to set the rflags.
        */
-       open->op_rflags = NFS4_OPEN_RESULT_LOCKTYPE_POSIX;
+       open->op_rflags |= NFS4_OPEN_RESULT_LOCKTYPE_POSIX;
        if (nfsd4_has_session(&resp->cstate))
                open->op_rflags |= NFS4_OPEN_RESULT_MAY_NOTIFY_LOCK;
        else if (!(open->op_openowner->oo_flags & NFS4_OO_CONFIRMED))

diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 178325fcb6cbf6adbb79f9aa0de535b87a547a24..5d413e751c744332790c2e2a042548a52995d091 100644 (file)
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -3421,7 +3421,8 @@ static __be32 nfsd4_encode_fattr4_xattr_support(struct xdr_stream *xdr,
 #define NFSD_OA_SHARE_ACCESS_WANT      (BIT(OPEN_ARGS_SHARE_ACCESS_WANT_ANY_DELEG)             | \
                                         BIT(OPEN_ARGS_SHARE_ACCESS_WANT_NO_DELEG)              | \
                                         BIT(OPEN_ARGS_SHARE_ACCESS_WANT_CANCEL)                | \
-                                        BIT(OPEN_ARGS_SHARE_ACCESS_WANT_DELEG_TIMESTAMPS))
+                                        BIT(OPEN_ARGS_SHARE_ACCESS_WANT_DELEG_TIMESTAMPS)      | \
+                                        BIT(OPEN_ARGS_SHARE_ACCESS_WANT_OPEN_XOR_DELEGATION))
 
 #define NFSD_OA_OPEN_CLAIM     (BIT(OPEN_ARGS_OPEN_CLAIM_NULL)         | \
                                 BIT(OPEN_ARGS_OPEN_CLAIM_PREVIOUS)     | \