pnfs-obj: objlayout_encode_layoutcommit implementation

* Define API for io-engines to report delta_space_used in IOs
* Encode the osd-layout specific information of the layoutcommit
  XDR buffer.
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: Benny Halevy <bhalevy@panasas.com>

fs/nfs/objlayout/objio_osd.c

@@ -1018,6 +1018,7 @@ static struct pnfs_layoutdriver_type objlayout_type = {
 
 	.free_deviceid_node	 = objio_free_deviceid_node,
 
+	.encode_layoutcommit	 = objlayout_encode_layoutcommit,
 	.encode_layoutreturn     = objlayout_encode_layoutreturn,
 };
 

fs/nfs/objlayout/objlayout.c

@@ -225,6 +225,7 @@ objlayout_iodone(struct objlayout_io_state *state)
 		struct objlayout *objlay = OBJLAYOUT(state->lseg->pls_layout);
 
 		spin_lock(&objlay->lock);
+		objlay->delta_space_valid = OBJ_DSU_INVALID;
 		list_add(&objlay->err_list, &state->err_list);
 		spin_unlock(&objlay->lock);
 	}
@@ -433,6 +434,35 @@ objlayout_write_pagelist(struct nfs_write_data *wdata,
 	return PNFS_ATTEMPTED;
 }
 
+void
+objlayout_encode_layoutcommit(struct pnfs_layout_hdr *pnfslay,
+			      struct xdr_stream *xdr,
+			      const struct nfs4_layoutcommit_args *args)
+{
+	struct objlayout *objlay = OBJLAYOUT(pnfslay);
+	struct pnfs_osd_layoutupdate lou;
+	__be32 *start;
+
+	dprintk("%s: Begin\n", __func__);
+
+	spin_lock(&objlay->lock);
+	lou.dsu_valid = (objlay->delta_space_valid == OBJ_DSU_VALID);
+	lou.dsu_delta = objlay->delta_space_used;
+	objlay->delta_space_used = 0;
+	objlay->delta_space_valid = OBJ_DSU_INIT;
+	lou.olu_ioerr_flag = !list_empty(&objlay->err_list);
+	spin_unlock(&objlay->lock);
+
+	start = xdr_reserve_space(xdr, 4);
+
+	BUG_ON(pnfs_osd_xdr_encode_layoutupdate(xdr, &lou));
+
+	*start = cpu_to_be32((xdr->p - start - 1) * 4);
+
+	dprintk("%s: Return delta_space_used %lld err %d\n", __func__,
+		lou.dsu_delta, lou.olu_ioerr_flag);
+}
+
 static int
 err_prio(u32 oer_errno)
 {

fs/nfs/objlayout/objlayout.h

@@ -51,6 +51,14 @@
 struct objlayout {
 	struct pnfs_layout_hdr pnfs_layout;
 
+	 /* for layout_commit */
+	enum osd_delta_space_valid_enum {
+		OBJ_DSU_INIT = 0,
+		OBJ_DSU_VALID,
+		OBJ_DSU_INVALID,
+	} delta_space_valid;
+	s64 delta_space_used;  /* consumed by write ops */
+
 	 /* for layout_return */
 	spinlock_t lock;
 	struct list_head err_list;
@@ -119,6 +127,23 @@ extern void objlayout_io_set_result(struct objlayout_io_state *state,
 			unsigned index, struct pnfs_osd_objid *pooid,
 			int osd_error, u64 offset, u64 length, bool is_write);
 
+static inline void
+objlayout_add_delta_space_used(struct objlayout_io_state *state, s64 space_used)
+{
+	struct objlayout *objlay = OBJLAYOUT(state->lseg->pls_layout);
+
+	/* If one of the I/Os errored out and the delta_space_used was
+	 * invalid we render the complete report as invalid. Protocol mandate
+	 * the DSU be accurate or not reported.
+	 */
+	spin_lock(&objlay->lock);
+	if (objlay->delta_space_valid != OBJ_DSU_INVALID) {
+		objlay->delta_space_valid = OBJ_DSU_VALID;
+		objlay->delta_space_used += space_used;
+	}
+	spin_unlock(&objlay->lock);
+}
+
 extern void objlayout_read_done(struct objlayout_io_state *state,
 				ssize_t status, bool sync);
 extern void objlayout_write_done(struct objlayout_io_state *state,
@@ -149,6 +174,11 @@ extern enum pnfs_try_status objlayout_write_pagelist(
 	struct nfs_write_data *,
 	int how);
 
+extern void objlayout_encode_layoutcommit(
+	struct pnfs_layout_hdr *,
+	struct xdr_stream *,
+	const struct nfs4_layoutcommit_args *);
+
 extern void objlayout_encode_layoutreturn(
 	struct pnfs_layout_hdr *,
 	struct xdr_stream *,