Function name and comment updates

Rename certain functions for more consistency when they share common 
features. Make comments clearer about what arguments should be passed 
to the insert and add functions.

Reviewed by: Sara Hartse <[email protected]>
Reviewed-by: Brian Behlendorf <[email protected]>
Reviewed-by: Matt Ahrens <[email protected]>
Signed-off-by: Paul Dagnelie <[email protected]>
Closes #9441 

3 files changed, 27 insertions, 8 deletions

diff --git a/module/zfs/btree.c b/module/zfs/btree.c
index 8f514caab..f099eb67c 100644
--- a/module/zfs/btree.c
+++ b/module/zfs/btree.c
@@ -980,7 +980,7 @@ zfs_btree_bulk_finish(zfs_btree_t *tree)
  * Insert value into tree at the location specified by where.
  */
 void
-zfs_btree_insert(zfs_btree_t *tree, const void *value,
+zfs_btree_add_idx(zfs_btree_t *tree, const void *value,
     const zfs_btree_index_t *where)
 {
 	zfs_btree_index_t idx = {0};
@@ -1294,7 +1294,7 @@ zfs_btree_add(zfs_btree_t *tree, const void *node)
 {
 	zfs_btree_index_t where = {0};
 	VERIFY3P(zfs_btree_find(tree, node, &where), ==, NULL);
-	zfs_btree_insert(tree, node, &where);
+	zfs_btree_add_idx(tree, node, &where);
 }
 
 /* Helper function to free a tree node. */
@@ -1542,7 +1542,7 @@ zfs_btree_remove_from_node(zfs_btree_t *tree, zfs_btree_core_t *node,
 
 /* Remove the element at the specific location. */
 void
-zfs_btree_remove_from(zfs_btree_t *tree, zfs_btree_index_t *where)
+zfs_btree_remove_idx(zfs_btree_t *tree, zfs_btree_index_t *where)
 {
 	size_t size = tree->bt_elem_size;
 	zfs_btree_hdr_t *hdr = where->bti_node;
@@ -1778,7 +1778,7 @@ zfs_btree_remove(zfs_btree_t *tree, const void *value)
 {
 	zfs_btree_index_t where = {0};
 	VERIFY3P(zfs_btree_find(tree, value, &where), !=, NULL);
-	zfs_btree_remove_from(tree, &where);
+	zfs_btree_remove_idx(tree, &where);
 }
 
 /* Return the number of elements in the tree. */
diff --git a/module/zfs/dsl_scan.c b/module/zfs/dsl_scan.c
index 3eacb42f1..b848f7ef3 100644
--- a/module/zfs/dsl_scan.c
+++ b/module/zfs/dsl_scan.c
@@ -2925,13 +2925,23 @@ scan_io_queue_fetch_ext(dsl_scan_io_queue_t *queue)
 		if (zfs_scan_issue_strategy == 1) {
 			return (range_tree_first(rt));
 		} else if (zfs_scan_issue_strategy == 2) {
+			/*
+			 * We need to get the original entry in the by_addr
+			 * tree so we can modify it.
+			 */
 			range_seg_t *size_rs =
 			    zfs_btree_first(&queue->q_exts_by_size, NULL);
+			if (size_rs == NULL)
+				return (NULL);
 			uint64_t start = rs_get_start(size_rs, rt);
 			uint64_t size = rs_get_end(size_rs, rt) - start;
 			range_seg_t *addr_rs = range_tree_find(rt, start,
 			    size);
 			ASSERT3P(addr_rs, !=, NULL);
+			ASSERT3U(rs_get_start(size_rs, rt), ==,
+			    rs_get_start(addr_rs, rt));
+			ASSERT3U(rs_get_end(size_rs, rt), ==,
+			    rs_get_end(addr_rs, rt));
 			return (addr_rs);
 		}
 	}
@@ -2948,12 +2958,21 @@ scan_io_queue_fetch_ext(dsl_scan_io_queue_t *queue)
 	if (scn->scn_checkpointing) {
 		return (range_tree_first(rt));
 	} else if (scn->scn_clearing) {
+		/*
+		 * We need to get the original entry in the by_addr
+		 * tree so we can modify it.
+		 */
 		range_seg_t *size_rs = zfs_btree_first(&queue->q_exts_by_size,
 		    NULL);
+		if (size_rs == NULL)
+			return (NULL);
 		uint64_t start = rs_get_start(size_rs, rt);
 		uint64_t size = rs_get_end(size_rs, rt) - start;
 		range_seg_t *addr_rs = range_tree_find(rt, start, size);
 		ASSERT3P(addr_rs, !=, NULL);
+		ASSERT3U(rs_get_start(size_rs, rt), ==, rs_get_start(addr_rs,
+		    rt));
+		ASSERT3U(rs_get_end(size_rs, rt), ==, rs_get_end(addr_rs, rt));
 		return (addr_rs);
 	} else {
 		return (NULL);
diff --git a/module/zfs/range_tree.c b/module/zfs/range_tree.c
index 0b369a438..1559605c2 100644
--- a/module/zfs/range_tree.c
+++ b/module/zfs/range_tree.c
@@ -349,7 +349,7 @@ range_tree_add_impl(void *arg, uint64_t start, uint64_t size, uint64_t fill)
 		uint64_t before_start = rs_get_start_raw(rs_before, rt);
 		uint64_t before_fill = rs_get_fill(rs_before, rt);
 		uint64_t after_fill = rs_get_fill(rs_after, rt);
-		zfs_btree_remove_from(&rt->rt_root, &where_before);
+		zfs_btree_remove_idx(&rt->rt_root, &where_before);
 
 		/*
 		 * We have to re-find the node because our old reference is
@@ -385,7 +385,7 @@ range_tree_add_impl(void *arg, uint64_t start, uint64_t size, uint64_t fill)
 		rs_set_start(rs, rt, start);
 		rs_set_end(rs, rt, end);
 		rs_set_fill(rs, rt, fill);
-		zfs_btree_insert(&rt->rt_root, rs, &where);
+		zfs_btree_add_idx(&rt->rt_root, rs, &where);
 	}
 
 	if (gap != 0) {
@@ -488,7 +488,7 @@ range_tree_remove_impl(range_tree_t *rt, uint64_t start, uint64_t size,
 
 		rs_copy(rs, &rs_tmp, rt);
 		if (zfs_btree_next(&rt->rt_root, &where, &where) != NULL)
-			zfs_btree_insert(&rt->rt_root, &newseg, &where);
+			zfs_btree_add_idx(&rt->rt_root, &newseg, &where);
 		else
 			zfs_btree_add(&rt->rt_root, &newseg);
 
@@ -503,7 +503,7 @@ range_tree_remove_impl(range_tree_t *rt, uint64_t start, uint64_t size,
 		rs_set_start(rs, rt, end);
 		rs_copy(rs, &rs_tmp, rt);
 	} else {
-		zfs_btree_remove_from(&rt->rt_root, &where);
+		zfs_btree_remove_idx(&rt->rt_root, &where);
 		rs = NULL;
 	}