diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index 6f9b2cd..572c8d0 100644
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -6132,17 +6132,9 @@
 	xfs_filblks_t			*blockcount,
 	xfs_exntst_t			state)
 {
-	xfs_fsblock_t			firstfsb;
 	int				error = 0;
 
-	/*
-	 * firstfsb is tied to the transaction lifetime and is used to
-	 * ensure correct AG locking order and schedule work item
-	 * continuations.  XFS_BUI_MAX_FAST_EXTENTS (== 1) restricts us
-	 * to only making one bmap call per transaction, so it should
-	 * be safe to have it as a local variable here.
-	 */
-	firstfsb = NULLFSBLOCK;
+	ASSERT(tp->t_firstblock == NULLFSBLOCK);
 
 	trace_xfs_bmap_deferred(tp->t_mountp,
 			XFS_FSB_TO_AGNO(tp->t_mountp, startblock), type,
@@ -6165,7 +6157,7 @@
 		break;
 	case XFS_BMAP_UNMAP:
 		error = __xfs_bunmapi(tp, ip, startoff, blockcount,
-				XFS_BMAPI_REMAP, 1, &firstfsb);
+				XFS_BMAPI_REMAP, 1, &tp->t_firstblock);
 		break;
 	default:
 		ASSERT(0);
diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
index dd563f4..0b2b528 100644
--- a/fs/xfs/xfs_bmap_util.c
+++ b/fs/xfs/xfs_bmap_util.c
@@ -1024,7 +1024,6 @@
 	struct xfs_mount	*mp = ip->i_mount;
 	struct xfs_trans	*tp;
 	struct xfs_defer_ops	dfops;
-	xfs_fsblock_t		firstfsb;
 	uint			resblks = XFS_DIOSTRAT_SPACE_RES(mp, 0);
 	int			error;
 
@@ -1042,9 +1041,9 @@
 
 	xfs_trans_ijoin(tp, ip, 0);
 
-	xfs_defer_init(tp, &dfops, &firstfsb);
-	error = xfs_bunmapi(tp, ip, startoffset_fsb, len_fsb, 0, 2, &firstfsb,
-			    done);
+	xfs_defer_init(tp, &dfops, &tp->t_firstblock);
+	error = xfs_bunmapi(tp, ip, startoffset_fsb, len_fsb, 0, 2,
+			    &tp->t_firstblock, done);
 	if (error)
 		goto out_bmap_cancel;
 
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index ab1fd69..3cdfd79 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -1543,7 +1543,6 @@
 	struct xfs_trans	*tp = *tpp;
 	struct xfs_defer_ops	*odfops = tp->t_dfops;
 	struct xfs_defer_ops	dfops;
-	xfs_fsblock_t		first_block;
 	xfs_fileoff_t		first_unmap_block;
 	xfs_fileoff_t		last_block;
 	xfs_filblks_t		unmap_len;
@@ -1580,9 +1579,9 @@
 	ASSERT(first_unmap_block < last_block);
 	unmap_len = last_block - first_unmap_block + 1;
 	while (!done) {
-		xfs_defer_init(tp, &dfops, &first_block);
+		xfs_defer_init(tp, &dfops, &tp->t_firstblock);
 		error = xfs_bunmapi(tp, ip, first_unmap_block, unmap_len, flags,
-				    XFS_ITRUNC_MAX_EXTENTS, &first_block,
+				    XFS_ITRUNC_MAX_EXTENTS, &tp->t_firstblock,
 				    &done);
 		if (error)
 			goto out_bmap_cancel;
diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
index d039762..83c02f6 100644
--- a/fs/xfs/xfs_reflink.c
+++ b/fs/xfs/xfs_reflink.c
@@ -627,7 +627,6 @@
 	struct xfs_trans		*tp;
 	xfs_fileoff_t			offset_fsb;
 	xfs_fileoff_t			end_fsb;
-	xfs_fsblock_t			firstfsb;
 	struct xfs_defer_ops		dfops;
 	int				error;
 	unsigned int			resblks;
@@ -695,10 +694,10 @@
 			goto prev_extent;
 
 		/* Unmap the old blocks in the data fork. */
-		xfs_defer_init(tp, &dfops, &firstfsb);
+		xfs_defer_init(tp, &dfops, &tp->t_firstblock);
 		rlen = del.br_blockcount;
 		error = __xfs_bunmapi(tp, ip, del.br_startoff, &rlen, 0, 1,
-				&firstfsb);
+				&tp->t_firstblock);
 		if (error)
 			goto out_defer;
 
@@ -1002,7 +1001,6 @@
 	struct xfs_mount	*mp = ip->i_mount;
 	bool			real_extent = xfs_bmap_is_real_extent(irec);
 	struct xfs_trans	*tp;
-	xfs_fsblock_t		firstfsb;
 	unsigned int		resblks;
 	struct xfs_defer_ops	dfops;
 	struct xfs_bmbt_irec	uirec;
@@ -1045,8 +1043,9 @@
 	/* Unmap the old blocks in the data fork. */
 	rlen = unmap_len;
 	while (rlen) {
-		xfs_defer_init(tp, &dfops, &firstfsb);
-		error = __xfs_bunmapi(tp, ip, destoff, &rlen, 0, 1, &firstfsb);
+		xfs_defer_init(tp, &dfops, &tp->t_firstblock);
+		error = __xfs_bunmapi(tp, ip, destoff, &rlen, 0, 1,
+				      &tp->t_firstblock);
 		if (error)
 			goto out_defer;
 
diff --git a/fs/xfs/xfs_symlink.c b/fs/xfs/xfs_symlink.c
index 583ca83..18d9b4d 100644
--- a/fs/xfs/xfs_symlink.c
+++ b/fs/xfs/xfs_symlink.c
@@ -400,7 +400,6 @@
 	xfs_buf_t	*bp;
 	int		done;
 	int		error;
-	xfs_fsblock_t	first_block;
 	struct xfs_defer_ops	dfops;
 	int		i;
 	xfs_mount_t	*mp;
@@ -440,7 +439,7 @@
 	 * Find the block(s) so we can inval and unmap them.
 	 */
 	done = 0;
-	xfs_defer_init(tp, &dfops, &first_block);
+	xfs_defer_init(tp, &dfops, &tp->t_firstblock);
 	nmaps = ARRAY_SIZE(mval);
 	error = xfs_bmapi_read(ip, 0, xfs_symlink_blocks(mp, size),
 				mval, &nmaps, 0);
@@ -462,7 +461,8 @@
 	/*
 	 * Unmap the dead block(s) to the dfops.
 	 */
-	error = xfs_bunmapi(tp, ip, 0, size, 0, nmaps, &first_block, &done);
+	error = xfs_bunmapi(tp, ip, 0, size, 0, nmaps, &tp->t_firstblock,
+			    &done);
 	if (error)
 		goto error_bmap_cancel;
 	ASSERT(done);