pnfs: alloc and free layout_hdr layoutdriver methods

[gfp_flags]
Signed-off-by: Benny Halevy <bhalevy@panasas.com>

fs/nfs/pnfs.c

@@ -177,13 +177,28 @@ get_layout_hdr(struct pnfs_layout_hdr *lo)
 	atomic_inc(&lo->plh_refcount);
 }
 
+static struct pnfs_layout_hdr *
+pnfs_alloc_layout_hdr(struct inode *ino, gfp_t gfp_flags)
+{
+	struct pnfs_layoutdriver_type *ld = NFS_SERVER(ino)->pnfs_curr_ld;
+	return ld->alloc_layout_hdr ? ld->alloc_layout_hdr(ino, gfp_flags) :
+		kzalloc(sizeof(struct pnfs_layout_hdr), gfp_flags);
+}
+
+static void
+pnfs_free_layout_hdr(struct pnfs_layout_hdr *lo)
+{
+	struct pnfs_layoutdriver_type *ld = NFS_SERVER(lo->plh_inode)->pnfs_curr_ld;
+	return ld->alloc_layout_hdr ? ld->free_layout_hdr(lo) : kfree(lo);
+}
+
 static void
 destroy_layout_hdr(struct pnfs_layout_hdr *lo)
 {
 	dprintk("%s: freeing layout cache %p\n", __func__, lo);
 	BUG_ON(!list_empty(&lo->plh_layouts));
 	NFS_I(lo->plh_inode)->layout = NULL;
-	kfree(lo);
+	pnfs_free_layout_hdr(lo);
 }
 
 static void
@@ -744,7 +759,7 @@ alloc_init_layout_hdr(struct inode *ino, gfp_t gfp_flags)
 {
 	struct pnfs_layout_hdr *lo;
 
-	lo = kzalloc(sizeof(struct pnfs_layout_hdr), gfp_flags);
+	lo = pnfs_alloc_layout_hdr(ino, gfp_flags);
 	if (!lo)
 		return NULL;
 	atomic_set(&lo->plh_refcount, 1);
@@ -777,7 +792,7 @@ pnfs_find_alloc_layout(struct inode *ino, gfp_t gfp_flags)
 	if (likely(nfsi->layout == NULL))	/* Won the race? */
 		nfsi->layout = new;
 	else
-		kfree(new);
+		pnfs_free_layout_hdr(new);
 	return nfsi->layout;
 }
 

fs/nfs/pnfs.h

@@ -73,6 +73,10 @@ struct pnfs_layoutdriver_type {
 	const u32 id;
 	const char *name;
 	struct module *owner;
+
+	struct pnfs_layout_hdr * (*alloc_layout_hdr) (struct inode *inode, gfp_t gfp_flags);
+	void (*free_layout_hdr) (struct pnfs_layout_hdr *);
+
 	struct pnfs_layout_segment * (*alloc_lseg) (struct pnfs_layout_hdr *layoutid, struct nfs4_layoutget_res *lgr, gfp_t gfp_flags);
 	void (*free_lseg) (struct pnfs_layout_segment *lseg);