[PATCH RFC 12/24] nfsd: encoders and decoders for GET_DIR_DELEGATION

[Jeff Layton]

This adds basic infrastructure for handing GET_DIR_DELEGATION calls from
clients, including the  decoders and encoders. For now, the server side
always just returns that the  delegation is GDDR_UNAVAIL (and that we
won't call back).

Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
---
 fs/nfsd/nfs4proc.c   | 30 ++++++++++++++++++++++
 fs/nfsd/nfs4xdr.c    | 72 ++++++++++++++++++++++++++++++++++++++++++++++++++--
 fs/nfsd/xdr4.h       |  8 ++++++
 include/linux/nfs4.h |  5 ++++
 4 files changed, 113 insertions(+), 2 deletions(-)

diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index 2927b1263f08..7973fe17bf3c 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -2173,6 +2173,18 @@ nfsd4_layout_verify(struct svc_export *exp, unsigned int layout_type)
 	return nfsd4_layout_ops[layout_type];
 }
 
+static __be32
+nfsd4_get_dir_delegation(struct svc_rqst *rqstp,
+			 struct nfsd4_compound_state *cstate,
+			 union nfsd4_op_u *u)
+{
+	struct nfsd4_get_dir_delegation *gdd = &u->get_dir_delegation;
+
+	/* FIXME: actually return a delegation */
+	gdd->nf_status = GDD4_UNAVAIL;
+	return nfs_ok;
+}
+
 static __be32
 nfsd4_getdeviceinfo(struct svc_rqst *rqstp,
 		struct nfsd4_compound_state *cstate, union nfsd4_op_u *u)
@@ -3082,6 +3094,18 @@ static u32 nfsd4_copy_notify_rsize(const struct svc_rqst *rqstp,
 		* sizeof(__be32);
 }
 
+static u32 nfsd4_get_dir_delegation_rsize(const struct svc_rqst *rqstp,
+					  const struct nfsd4_op *op)
+{
+	return (op_encode_hdr_size +
+		1 /* gddr_status */ +
+		op_encode_verifier_maxsz +
+		op_encode_stateid_maxsz +
+		2 /* gddr_notification */ +
+		2 /* gddr_child_attributes */ +
+		2 /* gddr_dir_attributes */);
+}
+
 #ifdef CONFIG_NFSD_PNFS
 static u32 nfsd4_getdeviceinfo_rsize(const struct svc_rqst *rqstp,
 				     const struct nfsd4_op *op)
@@ -3470,6 +3494,12 @@ static const struct nfsd4_operation nfsd4_ops[] = {
 		.op_get_currentstateid = nfsd4_get_freestateid,
 		.op_rsize_bop = nfsd4_only_status_rsize,
 	},
+	[OP_GET_DIR_DELEGATION] = {
+		.op_func = nfsd4_get_dir_delegation,
+		.op_flags = OP_MODIFIES_SOMETHING,
+		.op_name = "OP_GET_DIR_DELEGATION",
+		.op_rsize_bop = nfsd4_get_dir_delegation_rsize,
+	},
 #ifdef CONFIG_NFSD_PNFS
 	[OP_GETDEVICEINFO] = {
 		.op_func = nfsd4_getdeviceinfo,
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index fac938f563ad..3718bef74e9f 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -1732,6 +1732,40 @@ nfsd4_decode_free_stateid(struct nfsd4_compoundargs *argp,
 	return nfsd4_decode_stateid4(argp, &free_stateid->fr_stateid);
 }
 
+static __be32
+nfsd4_decode_get_dir_delegation(struct nfsd4_compoundargs *argp,
+		union nfsd4_op_u *u)
+{
+	struct nfsd4_get_dir_delegation *gdd = &u->get_dir_delegation;
+	struct timespec64 ts;
+	u32 signal_deleg_avail;
+	u32 attrs[1];
+	__be32 status;
+
+	memset(gdd, 0, sizeof(*gdd));
+
+	/* No signal_avail support for now (and maybe never) */
+	if (xdr_stream_decode_bool(argp->xdr, &signal_deleg_avail) < 0)
+		return nfserr_bad_xdr;
+	status = nfsd4_decode_bitmap4(argp, gdd->notification_types,
+				      ARRAY_SIZE(gdd->notification_types));
+	if (status)
+		return status;
+
+	/* For now, we don't support child or dir attr change notification */
+	status = nfsd4_decode_nfstime4(argp, &ts);
+	if (status)
+		return status;
+	/* No dir attr notification support yet either */
+	status = nfsd4_decode_nfstime4(argp, &ts);
+	if (status)
+		return status;
+	status = nfsd4_decode_bitmap4(argp, attrs, ARRAY_SIZE(attrs));
+	if (status)
+		return status;
+	return nfsd4_decode_bitmap4(argp, attrs, ARRAY_SIZE(attrs));
+}
+
 #ifdef CONFIG_NFSD_PNFS
 static __be32
 nfsd4_decode_getdeviceinfo(struct nfsd4_compoundargs *argp,
@@ -2370,7 +2404,7 @@ static const nfsd4_dec nfsd4_dec_ops[] = {
 	[OP_CREATE_SESSION]	= nfsd4_decode_create_session,
 	[OP_DESTROY_SESSION]	= nfsd4_decode_destroy_session,
 	[OP_FREE_STATEID]	= nfsd4_decode_free_stateid,
-	[OP_GET_DIR_DELEGATION]	= nfsd4_decode_notsupp,
+	[OP_GET_DIR_DELEGATION]	= nfsd4_decode_get_dir_delegation,
 #ifdef CONFIG_NFSD_PNFS
 	[OP_GETDEVICEINFO]	= nfsd4_decode_getdeviceinfo,
 	[OP_GETDEVICELIST]	= nfsd4_decode_notsupp,
@@ -5002,6 +5036,40 @@ nfsd4_encode_device_addr4(struct xdr_stream *xdr,
 	return nfserr_toosmall;
 }
 
+static __be32
+nfsd4_encode_get_dir_delegation(struct nfsd4_compoundres *resp, __be32 nfserr,
+				union nfsd4_op_u *u)
+{
+	struct xdr_stream *xdr = resp->xdr;
+	struct nfsd4_get_dir_delegation *gdd = &u->get_dir_delegation;
+
+	/* Encode the GDDR_* status code */
+	if (xdr_stream_encode_u32(xdr, gdd->nf_status) != XDR_UNIT)
+		return nfserr_resource;
+
+	/* if it's GDD4_UNAVAIL then we're (almost) done */
+	if (gdd->nf_status == GDD4_UNAVAIL) {
+		/* We never call back */
+		return nfsd4_encode_bool(xdr, false);
+	}
+
+	/* GDD4_OK case */
+	nfserr = nfsd4_encode_verifier4(xdr, &gdd->cookieverf);
+	if (nfserr)
+		return nfserr;
+	nfserr = nfsd4_encode_stateid4(xdr, &gdd->stateid);
+	if (nfserr)
+		return nfserr;
+	/* No notifications (yet) */
+	nfserr = nfsd4_encode_bitmap4(xdr, 0, 0, 0);
+	if (nfserr)
+		return nfserr;
+	nfserr = nfsd4_encode_bitmap4(xdr, 0, 0, 0);
+	if (nfserr)
+		return nfserr;
+	return nfsd4_encode_bitmap4(xdr, 0, 0, 0);
+}
+
 static __be32
 nfsd4_encode_getdeviceinfo(struct nfsd4_compoundres *resp, __be32 nfserr,
 		union nfsd4_op_u *u)
@@ -5580,7 +5648,7 @@ static const nfsd4_enc nfsd4_enc_ops[] = {
 	[OP_CREATE_SESSION]	= nfsd4_encode_create_session,
 	[OP_DESTROY_SESSION]	= nfsd4_encode_noop,
 	[OP_FREE_STATEID]	= nfsd4_encode_noop,
-	[OP_GET_DIR_DELEGATION]	= nfsd4_encode_noop,
+	[OP_GET_DIR_DELEGATION]	= nfsd4_encode_get_dir_delegation,
 #ifdef CONFIG_NFSD_PNFS
 	[OP_GETDEVICEINFO]	= nfsd4_encode_getdeviceinfo,
 	[OP_GETDEVICELIST]	= nfsd4_encode_noop,
diff --git a/fs/nfsd/xdr4.h b/fs/nfsd/xdr4.h
index 415516c1b27e..27de75f32dea 100644
--- a/fs/nfsd/xdr4.h
+++ b/fs/nfsd/xdr4.h
@@ -518,6 +518,13 @@ struct nfsd4_free_stateid {
 	stateid_t	fr_stateid;         /* request */
 };
 
+struct nfsd4_get_dir_delegation {
+	u32		notification_types[1];	/* request */
+	u32		nf_status;		/* response */
+	nfs4_verifier	cookieverf;		/* response */
+	stateid_t	stateid;		/* response */
+};
+
 /* also used for NVERIFY */
 struct nfsd4_verify {
 	u32		ve_bmval[3];        /* request */
@@ -797,6 +804,7 @@ struct nfsd4_op {
 		struct nfsd4_reclaim_complete	reclaim_complete;
 		struct nfsd4_test_stateid	test_stateid;
 		struct nfsd4_free_stateid	free_stateid;
+		struct nfsd4_get_dir_delegation	get_dir_delegation;
 		struct nfsd4_getdeviceinfo	getdeviceinfo;
 		struct nfsd4_layoutget		layoutget;
 		struct nfsd4_layoutcommit	layoutcommit;
diff --git a/include/linux/nfs4.h b/include/linux/nfs4.h
index ef8d2d618d5b..11ad088b411d 100644
--- a/include/linux/nfs4.h
+++ b/include/linux/nfs4.h
@@ -701,6 +701,11 @@ enum state_protect_how4 {
 	SP4_SSV		= 2
 };
 
+enum get_dir_delegation_non_fatal_res {
+	GDD4_OK		= 0,
+	GDD4_UNAVAIL	= 1
+};
+
 enum pnfs_layouttype {
 	LAYOUT_NFSV4_1_FILES  = 1,
 	LAYOUT_OSD2_OBJECTS = 2,

-- 
2.44.0