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>
diff --git a/fs/nfs/objlayout/objio_osd.c b/fs/nfs/objlayout/objio_osd.c
index 2255e2d..353821f 100644
--- a/fs/nfs/objlayout/objio_osd.c
+++ b/fs/nfs/objlayout/objio_osd.c
@@ -364,6 +364,9 @@
 	.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,
 
diff --git a/fs/nfs/objlayout/objlayout.c b/fs/nfs/objlayout/objlayout.c
index 10e5fca..f14b4da 100644
--- a/fs/nfs/objlayout/objlayout.c
+++ b/fs/nfs/objlayout/objlayout.c
@@ -42,6 +42,32 @@
 
 #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.
  */
 struct pnfs_layout_segment *
diff --git a/fs/nfs/objlayout/objlayout.h b/fs/nfs/objlayout/objlayout.h
index 0814271..fa02621 100644
--- a/fs/nfs/objlayout/objlayout.h
+++ b/fs/nfs/objlayout/objlayout.h
@@ -46,6 +46,19 @@
 #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
  */
 extern int objio_alloc_lseg(struct pnfs_layout_segment **outp,
@@ -66,6 +79,10 @@
 /*
  * 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 *,