xfs: create iterator error codes

Currently, xfs doesn't have generic error codes defined for "stop
iterating"; we just reuse the XFS_BTREE_QUERY_* return values.  This
looks a little weird if we're not actually iterating a btree index.
Before we start adding more iterators, we should create general
XFS_ITER_{CONTINUE,ABORT} return values and define the XFS_BTREE_QUERY_*
ones from that.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>

fs/xfs/libxfs/xfs_alloc.c

@@ -3137,7 +3137,7 @@ xfs_alloc_has_record(
 
 /*
  * Walk all the blocks in the AGFL.  The @walk_fn can return any negative
- * error code or XFS_BTREE_QUERY_RANGE_ABORT.
+ * error code or XFS_ITER_*.
  */
 int
 xfs_agfl_walk(

fs/xfs/libxfs/xfs_btree.h

@@ -465,8 +465,8 @@ uint xfs_btree_compute_maxlevels(uint *limits, unsigned long len);
 unsigned long long xfs_btree_calc_size(uint *limits, unsigned long long len);
 
 /* return codes */
-#define XFS_BTREE_QUERY_RANGE_CONTINUE	0	/* keep iterating */
-#define XFS_BTREE_QUERY_RANGE_ABORT	1	/* stop iterating */
+#define XFS_BTREE_QUERY_RANGE_CONTINUE	(XFS_ITER_CONTINUE) /* keep iterating */
+#define XFS_BTREE_QUERY_RANGE_ABORT	(XFS_ITER_ABORT)    /* stop iterating */
 typedef int (*xfs_btree_query_range_fn)(struct xfs_btree_cur *cur,
 		union xfs_btree_rec *rec, void *priv);
 

fs/xfs/libxfs/xfs_shared.h

@@ -177,4 +177,10 @@ struct xfs_ino_geometry {
 	unsigned int	agino_log;	/* #bits for agino in inum */
 };
 
+/* Keep iterating the data structure. */
+#define XFS_ITER_CONTINUE	(0)
+
+/* Stop iterating the data structure. */
+#define XFS_ITER_ABORT		(1)
+
 #endif /* __XFS_SHARED_H__ */

fs/xfs/scrub/agheader.c

@@ -639,7 +639,7 @@ xchk_agfl_block(
 	xchk_agfl_block_xref(sc, agbno);
 
 	if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
-		return XFS_BTREE_QUERY_RANGE_ABORT;
+		return XFS_ITER_ABORT;
 
 	return 0;
 }
@@ -730,7 +730,7 @@ xchk_agfl(
 	/* Check the blocks in the AGFL. */
 	error = xfs_agfl_walk(sc->mp, XFS_BUF_TO_AGF(sc->sa.agf_bp),
 			sc->sa.agfl_bp, xchk_agfl_block, &sai);
-	if (error == XFS_BTREE_QUERY_RANGE_ABORT) {
+	if (error == XFS_ITER_ABORT) {
 		error = 0;
 		goto out_free;
 	}

fs/xfs/scrub/repair.c

@@ -664,7 +664,7 @@ xrep_findroot_agfl_walk(
 {
 	xfs_agblock_t		*agbno = priv;
 
-	return (*agbno == bno) ? XFS_BTREE_QUERY_RANGE_ABORT : 0;
+	return (*agbno == bno) ? XFS_ITER_ABORT : 0;
 }
 
 /* Does this block match the btree information passed in? */
@@ -694,7 +694,7 @@ xrep_findroot_block(
 	if (owner == XFS_RMAP_OWN_AG) {
 		error = xfs_agfl_walk(mp, ri->agf, ri->agfl_bp,
 				xrep_findroot_agfl_walk, &agbno);
-		if (error == XFS_BTREE_QUERY_RANGE_ABORT)
+		if (error == XFS_ITER_ABORT)
 			return 0;
 		if (error)
 			return error;

fs/xfs/xfs_dquot.c

@@ -1239,7 +1239,7 @@ xfs_qm_exit(void)
 /*
  * Iterate every dquot of a particular type.  The caller must ensure that the
  * particular quota type is active.  iter_fn can return negative error codes,
- * or XFS_BTREE_QUERY_RANGE_ABORT to indicate that it wants to stop iterating.
+ * or XFS_ITER_ABORT to indicate that it wants to stop iterating.
  */
 int
 xfs_qm_dqiterate(