pnfs-obj: define per-inode private structure

allocate and deallocate per-inode private pnfs_layout_hdr
in preparation for I/O implementation.
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: Benny Halevy <bhalevy@panasas.com>

fs/nfs/objlayout/objio_osd.c

@@ -364,6 +364,9 @@ static struct pnfs_layoutdriver_type objlayout_type = {
 	.id = LAYOUT_OSD2_OBJECTS,
 	.name = "LAYOUT_OSD2_OBJECTS",
 
+	.alloc_layout_hdr        = objlayout_alloc_layout_hdr,
+	.free_layout_hdr         = objlayout_free_layout_hdr,
+
 	.alloc_lseg              = objlayout_alloc_lseg,
 	.free_lseg               = objlayout_free_lseg,
 

fs/nfs/objlayout/objlayout.c

@@ -41,6 +41,32 @@
 #include "objlayout.h"
 
 #define NFSDBG_FACILITY         NFSDBG_PNFS_LD
+/*
+ * Create a objlayout layout structure for the given inode and return it.
+ */
+struct pnfs_layout_hdr *
+objlayout_alloc_layout_hdr(struct inode *inode, gfp_t gfp_flags)
+{
+	struct objlayout *objlay;
+
+	objlay = kzalloc(sizeof(struct objlayout), gfp_flags);
+	dprintk("%s: Return %p\n", __func__, objlay);
+	return &objlay->pnfs_layout;
+}
+
+/*
+ * Free an objlayout layout structure
+ */
+void
+objlayout_free_layout_hdr(struct pnfs_layout_hdr *lo)
+{
+	struct objlayout *objlay = OBJLAYOUT(lo);
+
+	dprintk("%s: objlay %p\n", __func__, objlay);
+
+	kfree(objlay);
+}
+
 /*
  * Unmarshall layout and store it in pnfslay.
  */

fs/nfs/objlayout/objlayout.h

@@ -45,6 +45,19 @@
 #include <linux/pnfs_osd_xdr.h>
 #include "../pnfs.h"
 
+/*
+ * per-inode layout
+ */
+struct objlayout {
+	struct pnfs_layout_hdr pnfs_layout;
+};
+
+static inline struct objlayout *
+OBJLAYOUT(struct pnfs_layout_hdr *lo)
+{
+	return container_of(lo, struct objlayout, pnfs_layout);
+}
+
 /*
  * Raid engine I/O API
  */
@@ -66,6 +79,10 @@ extern void objlayout_put_deviceinfo(struct pnfs_osd_deviceaddr *deviceaddr);
 /*
  * exported generic objects function vectors
  */
+
+extern struct pnfs_layout_hdr *objlayout_alloc_layout_hdr(struct inode *, gfp_t gfp_flags);
+extern void objlayout_free_layout_hdr(struct pnfs_layout_hdr *);
+
 extern struct pnfs_layout_segment *objlayout_alloc_lseg(
 	struct pnfs_layout_hdr *,
 	struct nfs4_layoutget_res *,