[PATCH 1/4] NFS: Add an outline for the CB_NOTIFY operation

[Anna Schumaker <anna@kernel.org>]

From: Anna Schumaker <anna.schumaker@oracle.com>

Support for individual notification types will be added over the next
few patches.

Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>
Signed-off-by: Anna Schumaker <anna.schumaker@hammerspace.com>
---
 fs/nfs/callback.h      | 14 +++++++++++
 fs/nfs/callback_proc.c |  9 +++++++
 fs/nfs/callback_xdr.c  | 54 +++++++++++++++++++++++++++++++++++++++++-
 fs/nfs/nfs4xdr.c       |  2 +-
 include/linux/nfs4.h   |  3 +++
 5 files changed, 80 insertions(+), 2 deletions(-)

diff --git a/fs/nfs/callback.h b/fs/nfs/callback.h
index 2a721c422d48..f7cc5b6931bf 100644
--- a/fs/nfs/callback.h
+++ b/fs/nfs/callback.h
@@ -143,6 +143,20 @@ struct cb_layoutrecallargs {
 extern __be32 nfs4_callback_layoutrecall(void *argp, void *resp,
 		struct cb_process_state *cps);
 
+struct cb_notify_changes {
+	u32 notify_mask;
+};
+
+struct cb_notifyargs {
+	nfs4_stateid			cna_stateid;
+	struct nfs_fh			cna_fh;
+	uint32_t			cna_n_changes;
+	struct cb_notify_changes	*cna_changes;
+};
+
+extern __be32 nfs4_callback_notify(void *argp, void *resp,
+				   struct cb_process_state *cps);
+
 struct cb_devicenotifyitem {
 	uint32_t		cbd_notify_type;
 	uint32_t		cbd_layout_type;
diff --git a/fs/nfs/callback_proc.c b/fs/nfs/callback_proc.c
index 10f2354ba304..5c414b3b01d8 100644
--- a/fs/nfs/callback_proc.c
+++ b/fs/nfs/callback_proc.c
@@ -368,6 +368,15 @@ static void pnfs_recall_all_layouts(struct nfs_client *clp,
 	do_callback_layoutrecall(clp, &args, cps);
 }
 
+__be32 nfs4_callback_notify(void *argp, void *resp,
+			    struct cb_process_state *cps)
+{
+	struct cb_notifyargs *args = argp;
+
+	kfree(args->cna_changes);
+	return 0;
+}
+
 __be32 nfs4_callback_devicenotify(void *argp, void *resp,
 				  struct cb_process_state *cps)
 {
diff --git a/fs/nfs/callback_xdr.c b/fs/nfs/callback_xdr.c
index 4382baddc9ee..b96d0028fa3d 100644
--- a/fs/nfs/callback_xdr.c
+++ b/fs/nfs/callback_xdr.c
@@ -31,6 +31,7 @@
 #define CB_OP_RECALL_RES_MAXSZ		(CB_OP_HDR_RES_MAXSZ)
 
 #define CB_OP_LAYOUTRECALL_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ)
+#define CB_OP_NOTIFY_RES_MAXSZ		(CB_OP_HDR_RES_MAXSZ)
 #define CB_OP_DEVICENOTIFY_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ)
 #define CB_OP_SEQUENCE_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ + \
 					 NFS4_MAX_SESSIONID_LEN + \
@@ -251,6 +252,52 @@ static __be32 decode_layoutrecall_args(struct svc_rqst *rqstp,
 	return 0;
 }
 
+static
+__be32 decode_notify_args(struct svc_rqst *rqstp,
+			  struct xdr_stream *xdr,
+			  void *argp)
+{
+	struct cb_notifyargs *args = argp;
+	__be32 status;
+	size_t res;
+	__be32 *p;
+	int i;
+
+	status = decode_stateid(xdr, &args->cna_stateid);
+	if (unlikely(status != 0))
+		return status;
+
+	status = decode_fh(xdr, &args->cna_fh);
+	if (unlikely(status != 0))
+		return status;
+
+	p = xdr_inline_decode(xdr, 4);
+	if (unlikely(!p))
+		goto out;
+
+	args->cna_n_changes = ntohl(*p++);
+	args->cna_changes = kmalloc_array(args->cna_n_changes,
+					  sizeof(*args->cna_changes),
+					  GFP_KERNEL);
+	if (!args->cna_changes)
+		goto out;
+
+	for (i = 0; i < args->cna_n_changes; i++) {
+		struct cb_notify_changes *change = &args->cna_changes[i];
+
+		res = xdr_stream_decode_uint32_array(xdr,
+						     &change->notify_mask, 1);
+		if (unlikely(res < 0))
+			goto err;
+	}
+
+	return 0;
+err:
+	kfree(args->cna_changes);
+out:
+	return htonl(NFS4ERR_BADXDR);
+}
+
 static
 __be32 decode_devicenotify_args(struct svc_rqst *rqstp,
 				struct xdr_stream *xdr,
@@ -797,12 +844,12 @@ preprocess_nfs41_op(int nop, unsigned int op_nr, struct callback_op **op)
 	case OP_CB_RECALL_ANY:
 	case OP_CB_RECALL_SLOT:
 	case OP_CB_LAYOUTRECALL:
+	case OP_CB_NOTIFY:
 	case OP_CB_NOTIFY_DEVICEID:
 	case OP_CB_NOTIFY_LOCK:
 		*op = &callback_ops[op_nr];
 		break;
 
-	case OP_CB_NOTIFY:
 	case OP_CB_PUSH_DELEG:
 	case OP_CB_RECALLABLE_OBJ_AVAIL:
 	case OP_CB_WANTS_CANCELLED:
@@ -1034,6 +1081,11 @@ static struct callback_op callback_ops[] = {
 		.decode_args = decode_layoutrecall_args,
 		.res_maxsize = CB_OP_LAYOUTRECALL_RES_MAXSZ,
 	},
+	[OP_CB_NOTIFY] = {
+		.process_op = nfs4_callback_notify,
+		.decode_args = decode_notify_args,
+		.res_maxsize = CB_OP_NOTIFY_RES_MAXSZ,
+	},
 	[OP_CB_NOTIFY_DEVICEID] = {
 		.process_op = nfs4_callback_devicenotify,
 		.decode_args = decode_devicenotify_args,
diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index c23c2eee1b5c..64b8fd061852 100644
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -2011,7 +2011,7 @@ static void
 encode_get_dir_delegation(struct xdr_stream *xdr, struct compound_hdr *hdr)
 {
 	struct timespec64 ts = { 0, 0 };
-	u32 notifications[1] = { 0 };
+	u32 notifications[1] = { CB_NOTIFY4_GFLAG_EXTEND };
 	u32 attributes[1] = { 0 };
 	__be32 *p;
 
diff --git a/include/linux/nfs4.h b/include/linux/nfs4.h
index 44e5e9fa12e1..fcf0eee55c35 100644
--- a/include/linux/nfs4.h
+++ b/include/linux/nfs4.h
@@ -482,6 +482,9 @@ enum {
 #define THRESHOLD_RD_IO                 (1UL << 2)
 #define THRESHOLD_WR_IO                 (1UL << 3)
 
+/* Directory Delegation / CB_NOTIFY bits */
+#define CB_NOTIFY4_GFLAG_EXTEND		(1UL << 6)
+
 #define NFSPROC4_NULL 0
 #define NFSPROC4_COMPOUND 1
 #define NFS4_VERSION 4
-- 
2.55.0