xfs: reduce the size of struct xfs_extent_free_item

We only use EFIs to free metadata blocks -- not regular data/attr fork
extents. Remove all the fields that we never use, for a net reduction
of 16 bytes.

Signed-off-by: Darrick J. Wong <[e-mail]>
Reviewed-by: Chandan Babu R <[e-mail]>

fs/xfs/libxfs/xfs_alloc.c

···
 	ASSERT(xfs_extfree_item_cache != NULL);
 	ASSERT(oinfo != NULL);
 
-	new = kmem_cache_alloc(xfs_extfree_item_cache,
+	new = kmem_cache_zalloc(xfs_extfree_item_cache,
 			       GFP_KERNEL | __GFP_NOFAIL);
 	new->xefi_startblock = XFS_AGB_TO_FSB(mp, agno, agbno);
 	new->xefi_blockcount = 1;
-	new->xefi_oinfo = *oinfo;
-	new->xefi_skip_discard = false;
+	new->xefi_owner = oinfo->oi_owner;
 
 	trace_xfs_agfl_free_defer(mp, agno, 0, agbno, 1);
 
···
 #endif
 	ASSERT(xfs_extfree_item_cache != NULL);
 
-	new = kmem_cache_alloc(xfs_extfree_item_cache,
+	new = kmem_cache_zalloc(xfs_extfree_item_cache,
 			       GFP_KERNEL | __GFP_NOFAIL);
 	new->xefi_startblock = bno;
 	new->xefi_blockcount = (xfs_extlen_t)len;
-	if (oinfo)
-		new->xefi_oinfo = *oinfo;
-	else
-		new->xefi_oinfo = XFS_RMAP_OINFO_SKIP_UPDATE;
-	new->xefi_skip_discard = skip_discard;
+	if (skip_discard)
+		new->xefi_flags |= XFS_EFI_SKIP_DISCARD;
+	if (oinfo) {
+		ASSERT(oinfo->oi_offset == 0);
+
+		if (oinfo->oi_flags & XFS_OWNER_INFO_ATTR_FORK)
+			new->xefi_flags |= XFS_EFI_ATTR_FORK;
+		if (oinfo->oi_flags & XFS_OWNER_INFO_BMBT_BLOCK)
+			new->xefi_flags |= XFS_EFI_BMBT_BLOCK;
+		new->xefi_owner = oinfo->oi_owner;
+	} else {
+		new->xefi_owner = XFS_RMAP_OWN_NULL;
+	}
 	trace_xfs_bmap_free_defer(tp->t_mountp,
 			XFS_FSB_TO_AGNO(tp->t_mountp, bno), 0,
 			XFS_FSB_TO_AGBNO(tp->t_mountp, bno), len);

fs/xfs/libxfs/xfs_alloc.h

···
  */
 struct xfs_extent_free_item {
 	struct list_head	xefi_list;
+	uint64_t		xefi_owner;
 	xfs_fsblock_t		xefi_startblock;/* starting fs block number */
 	xfs_extlen_t		xefi_blockcount;/* number of blocks in extent */
-	bool			xefi_skip_discard;
-	struct xfs_owner_info	xefi_oinfo;	/* extent owner */
+	unsigned int		xefi_flags;
 };
+
+#define XFS_EFI_SKIP_DISCARD	(1U << 0) /* don't issue discard */
+#define XFS_EFI_ATTR_FORK	(1U << 1) /* freeing attr fork block */
+#define XFS_EFI_BMBT_BLOCK	(1U << 2) /* freeing bmap btree block */
 
 static inline void
 xfs_free_extent_later(

fs/xfs/xfs_extfree_item.c

···
 	struct list_head		*item,
 	struct xfs_btree_cur		**state)
 {
+	struct xfs_owner_info		oinfo = { };
 	struct xfs_extent_free_item	*free;
 	int				error;
 
 	free = container_of(item, struct xfs_extent_free_item, xefi_list);
+	oinfo.oi_owner = free->xefi_owner;
+	if (free->xefi_flags & XFS_EFI_ATTR_FORK)
+		oinfo.oi_flags |= XFS_OWNER_INFO_ATTR_FORK;
+	if (free->xefi_flags & XFS_EFI_BMBT_BLOCK)
+		oinfo.oi_flags |= XFS_OWNER_INFO_BMBT_BLOCK;
 	error = xfs_trans_free_extent(tp, EFD_ITEM(done),
 			free->xefi_startblock,
 			free->xefi_blockcount,
-			&free->xefi_oinfo, free->xefi_skip_discard);
+			&oinfo, free->xefi_flags & XFS_EFI_SKIP_DISCARD);
 	kmem_cache_free(xfs_extfree_item_cache, free);
 	return error;
 }
···
 	struct list_head		*item,
 	struct xfs_btree_cur		**state)
 {
+	struct xfs_owner_info		oinfo = { };
 	struct xfs_mount		*mp = tp->t_mountp;
 	struct xfs_efd_log_item		*efdp = EFD_ITEM(done);
 	struct xfs_extent_free_item	*free;
···
 	ASSERT(free->xefi_blockcount == 1);
 	agno = XFS_FSB_TO_AGNO(mp, free->xefi_startblock);
 	agbno = XFS_FSB_TO_AGBNO(mp, free->xefi_startblock);
+	oinfo.oi_owner = free->xefi_owner;
 
 	trace_xfs_agfl_free_deferred(mp, agno, 0, agbno, free->xefi_blockcount);
 
 	error = xfs_alloc_read_agf(mp, tp, agno, 0, &agbp);
 	if (!error)
-		error = xfs_free_agfl_block(tp, agno, agbno, agbp,
-					    &free->xefi_oinfo);
+		error = xfs_free_agfl_block(tp, agno, agbno, agbp, &oinfo);
 
 	/*
 	 * Mark the transaction dirty, even on error. This ensures the