pnfsblock: basic extent code

Adds structures and basic create/delete code for extents.

Signed-off-by: Fred Isaman <iisaman@citi.umich.edu>
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
Signed-off-by: Zhang Jingwang <Jingwang.Zhang@emc.com>
Signed-off-by: Benny Halevy <bhalevy@tonian.com>
Signed-off-by: Jim Rees <rees@umich.edu>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/blocklayout/blocklayout.c b/fs/nfs/blocklayout/blocklayout.c
index 1f5287c..8dde372 100644
--- a/fs/nfs/blocklayout/blocklayout.c
+++ b/fs/nfs/blocklayout/blocklayout.c
@@ -53,12 +53,24 @@
 	return PNFS_NOT_ATTEMPTED;
 }
 
-/* STUB */
+/* FIXME - range ignored */
 static void
-release_extents(struct pnfs_block_layout *bl,
-		struct pnfs_layout_range *range)
+release_extents(struct pnfs_block_layout *bl, struct pnfs_layout_range *range)
 {
-	return;
+	int i;
+	struct pnfs_block_extent *be;
+
+	spin_lock(&bl->bl_ext_lock);
+	for (i = 0; i < EXTENT_LISTS; i++) {
+		while (!list_empty(&bl->bl_extents[i])) {
+			be = list_first_entry(&bl->bl_extents[i],
+					      struct pnfs_block_extent,
+					      be_node);
+			list_del(&be->be_node);
+			bl_put_extent(be);
+		}
+	}
+	spin_unlock(&bl->bl_ext_lock);
 }
 
 /* STUB */