xfs: add a xfs_iext_update_extent helper

This helper is used to update an extent record based on the extent index,
and can be used to provide a level of abstractions between callers that
want to modify in-core extent records and the details of the extent list
implementation.

Also switch all users of the xfs_bmbt_set_all(xfs_iext_get_ext(...))
pattern to this new helper.

Signed-off-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_bmap.c

@@ -4918,7 +4918,7 @@ xfs_bmap_del_extent_delay(
 		da_new = XFS_FILBLKS_MIN(xfs_bmap_worst_indlen(ip,
 				got->br_blockcount), da_old);
 		got->br_startblock = nullstartblock((int)da_new);
-		xfs_bmbt_set_all(xfs_iext_get_ext(ifp, *idx), got);
+		xfs_iext_update_extent(ifp, *idx, got);
 		trace_xfs_bmap_post_update(ip, *idx, state, _THIS_IP_);
 		break;
 	case BMAP_RIGHT_CONTIG:
@@ -4930,7 +4930,7 @@ xfs_bmap_del_extent_delay(
 		da_new = XFS_FILBLKS_MIN(xfs_bmap_worst_indlen(ip,
 				got->br_blockcount), da_old);
 		got->br_startblock = nullstartblock((int)da_new);
-		xfs_bmbt_set_all(xfs_iext_get_ext(ifp, *idx), got);
+		xfs_iext_update_extent(ifp, *idx, got);
 		trace_xfs_bmap_post_update(ip, *idx, state, _THIS_IP_);
 		break;
 	case 0:
@@ -4956,7 +4956,7 @@ xfs_bmap_del_extent_delay(
 						       del->br_blockcount);
 
 		got->br_startblock = nullstartblock((int)got_indlen);
-		xfs_bmbt_set_all(xfs_iext_get_ext(ifp, *idx), got);
+		xfs_iext_update_extent(ifp, *idx, got);
 		trace_xfs_bmap_post_update(ip, *idx, 0, _THIS_IP_);
 
 		new.br_startoff = del_endoff;
@@ -5026,7 +5026,7 @@ xfs_bmap_del_extent_cow(
 		got->br_startoff = del_endoff;
 		got->br_blockcount -= del->br_blockcount;
 		got->br_startblock = del->br_startblock + del->br_blockcount;
-		xfs_bmbt_set_all(xfs_iext_get_ext(ifp, *idx), got);
+		xfs_iext_update_extent(ifp, *idx, got);
 		trace_xfs_bmap_post_update(ip, *idx, state, _THIS_IP_);
 		break;
 	case BMAP_RIGHT_CONTIG:
@@ -5035,7 +5035,7 @@ xfs_bmap_del_extent_cow(
 		 */
 		trace_xfs_bmap_pre_update(ip, *idx, state, _THIS_IP_);
 		got->br_blockcount -= del->br_blockcount;
-		xfs_bmbt_set_all(xfs_iext_get_ext(ifp, *idx), got);
+		xfs_iext_update_extent(ifp, *idx, got);
 		trace_xfs_bmap_post_update(ip, *idx, state, _THIS_IP_);
 		break;
 	case 0:
@@ -5044,7 +5044,7 @@ xfs_bmap_del_extent_cow(
 		 */
 		trace_xfs_bmap_pre_update(ip, *idx, state, _THIS_IP_);
 		got->br_blockcount = del->br_startoff - got->br_startoff;
-		xfs_bmbt_set_all(xfs_iext_get_ext(ifp, *idx), got);
+		xfs_iext_update_extent(ifp, *idx, got);
 		trace_xfs_bmap_post_update(ip, *idx, state, _THIS_IP_);
 
 		new.br_startoff = del_endoff;

fs/xfs/libxfs/xfs_inode_fork.c

@@ -2023,3 +2023,15 @@ xfs_iext_get_extent(
 	xfs_bmbt_get_all(xfs_iext_get_ext(ifp, idx), gotp);
 	return true;
 }
+
+void
+xfs_iext_update_extent(
+	struct xfs_ifork	*ifp,
+	xfs_extnum_t		idx,
+	struct xfs_bmbt_irec	*gotp)
+{
+	ASSERT(idx >= 0);
+	ASSERT(idx < xfs_iext_count(ifp));
+
+	xfs_bmbt_set_all(xfs_iext_get_ext(ifp, idx), gotp);
+}

fs/xfs/libxfs/xfs_inode_fork.h

@@ -187,6 +187,8 @@ bool		xfs_iext_lookup_extent(struct xfs_inode *ip,
 			xfs_extnum_t *idxp, struct xfs_bmbt_irec *gotp);
 bool		xfs_iext_get_extent(struct xfs_ifork *ifp, xfs_extnum_t idx,
 			struct xfs_bmbt_irec *gotp);
+void		xfs_iext_update_extent(struct xfs_ifork *ifp, xfs_extnum_t idx,
+			struct xfs_bmbt_irec *gotp);
 
 extern struct kmem_zone	*xfs_ifork_zone;