xfs: remove unused btree cursor bc_private.a.dfops field

The xfs_btree_cur.bc_private.a.dfops field is only ever initialized
by the refcountbt cursor init function. The only caller of that
function with a non-NULL dfops is from deferred completion context,
which already has attached to ->t_dfops.

In addition to that, the only actual reference of a.dfops is the
cursor duplication function, which means the field is effectively
unused.

Remove the dfops field from the bc_private.a union. Any future users
can acquire the dfops from the transaction. This patch does not
change behavior.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

fs/xfs/libxfs/xfs_btree.h

@@ -209,7 +209,6 @@ typedef struct xfs_btree_cur
 	union {
 		struct {			/* needed for BNO, CNT, INO */
 			struct xfs_buf	*agbp;	/* agf/agi buffer pointer */
-			struct xfs_defer_ops *dfops;	/* deferred updates */
 			xfs_agnumber_t	agno;	/* ag number */
 			union xfs_btree_cur_private	priv;
 		} a;

fs/xfs/libxfs/xfs_refcount.c

@@ -1132,7 +1132,7 @@ xfs_refcount_finish_one(
 		if (!agbp)
 			return -EFSCORRUPTED;
 
-		rcur = xfs_refcountbt_init_cursor(mp, tp, agbp, agno, dfops);
+		rcur = xfs_refcountbt_init_cursor(mp, tp, agbp, agno);
 		if (!rcur) {
 			error = -ENOMEM;
 			goto out_cur;
@@ -1666,7 +1666,7 @@ xfs_refcount_recover_cow_leftovers(
 		error = -ENOMEM;
 		goto out_trans;
 	}
-	cur = xfs_refcountbt_init_cursor(mp, tp, agbp, agno, NULL);
+	cur = xfs_refcountbt_init_cursor(mp, tp, agbp, agno);
 
 	/* Find all the leftover CoW staging extents. */
 	memset(&low, 0, sizeof(low));

fs/xfs/libxfs/xfs_refcount_btree.c

@@ -27,8 +27,7 @@ xfs_refcountbt_dup_cursor(
 	struct xfs_btree_cur	*cur)
 {
 	return xfs_refcountbt_init_cursor(cur->bc_mp, cur->bc_tp,
-			cur->bc_private.a.agbp, cur->bc_private.a.agno,
-			cur->bc_private.a.dfops);
+			cur->bc_private.a.agbp, cur->bc_private.a.agno);
 }
 
 STATIC void
@@ -323,8 +322,7 @@ xfs_refcountbt_init_cursor(
 	struct xfs_mount	*mp,
 	struct xfs_trans	*tp,
 	struct xfs_buf		*agbp,
-	xfs_agnumber_t		agno,
-	struct xfs_defer_ops	*dfops)
+	xfs_agnumber_t		agno)
 {
 	struct xfs_agf		*agf = XFS_BUF_TO_AGF(agbp);
 	struct xfs_btree_cur	*cur;
@@ -344,7 +342,6 @@ xfs_refcountbt_init_cursor(
 
 	cur->bc_private.a.agbp = agbp;
 	cur->bc_private.a.agno = agno;
-	cur->bc_private.a.dfops = dfops;
 	cur->bc_flags |= XFS_BTREE_CRC_BLOCKS;
 
 	cur->bc_private.a.priv.refc.nr_ops = 0;

fs/xfs/libxfs/xfs_refcount_btree.h

@@ -44,8 +44,8 @@ struct xfs_mount;
 		 ((index) - 1) * sizeof(xfs_refcount_ptr_t)))
 
 extern struct xfs_btree_cur *xfs_refcountbt_init_cursor(struct xfs_mount *mp,
-		struct xfs_trans *tp, struct xfs_buf *agbp, xfs_agnumber_t agno,
-		struct xfs_defer_ops *dfops);
+		struct xfs_trans *tp, struct xfs_buf *agbp,
+		xfs_agnumber_t agno);
 extern int xfs_refcountbt_maxrecs(int blocklen, bool leaf);
 extern void xfs_refcountbt_compute_maxlevels(struct xfs_mount *mp);
 

fs/xfs/scrub/common.c

@@ -499,7 +499,7 @@ xfs_scrub_ag_btcur_init(
 	/* Set up a refcountbt cursor for cross-referencing. */
 	if (sa->agf_bp && xfs_sb_version_hasreflink(&mp->m_sb)) {
 		sa->refc_cur = xfs_refcountbt_init_cursor(mp, sc->tp,
-				sa->agf_bp, agno, NULL);
+				sa->agf_bp, agno);
 		if (!sa->refc_cur)
 			goto err;
 	}

fs/xfs/xfs_fsmap.c

@@ -214,7 +214,7 @@ xfs_getfsmap_is_shared(
 	/* Are there any shared blocks here? */
 	flen = 0;
 	cur = xfs_refcountbt_init_cursor(mp, tp, info->agf_bp,
-			info->agno, NULL);
+			info->agno);
 
 	error = xfs_refcount_find_shared(cur, rec->rm_startblock,
 			rec->rm_blockcount, &fbno, &flen, false);

fs/xfs/xfs_reflink.c

@@ -157,7 +157,7 @@ xfs_reflink_find_shared(
 	if (!agbp)
 		return -ENOMEM;
 
-	cur = xfs_refcountbt_init_cursor(mp, tp, agbp, agno, NULL);
+	cur = xfs_refcountbt_init_cursor(mp, tp, agbp, agno);
 
 	error = xfs_refcount_find_shared(cur, agbno, aglen, fbno, flen,
 			find_end_of_shared);