btrfs: refactor mergable_maps() for more readability

At mergable_maps() instead of having a single if statement with many
ORed and ANDed conditions, refactor it with multiple if statements that
check a single condition and return immediately once a requirement fails.
This makes it easier to read.

Also change the return type from int to bool, make the arguments const
and rename the function from mergable_maps() to mergeable_maps().

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c
index 72df548a4c865a37274d2d450cd4bb44d0a9a011..0d1167f454d2a3bbeddfa51823d4039a04589a5a 100644 (file)
--- a/fs/btrfs/extent_map.c
+++ b/fs/btrfs/extent_map.c
@@ -211,19 +211,19 @@ static bool can_merge_extent_map(const struct extent_map *em)
 }
 
 /* Check to see if two extent_map structs are adjacent and safe to merge. */
-static int mergable_maps(struct extent_map *prev, struct extent_map *next)
+static bool mergeable_maps(const struct extent_map *prev, const struct extent_map *next)
 {
-       if (extent_map_end(prev) == next->start &&
-           prev->flags == next->flags &&
-           ((next->block_start == EXTENT_MAP_HOLE &&
-             prev->block_start == EXTENT_MAP_HOLE) ||
-            (next->block_start == EXTENT_MAP_INLINE &&
-             prev->block_start == EXTENT_MAP_INLINE) ||
-            (next->block_start < EXTENT_MAP_LAST_BYTE - 1 &&
-             next->block_start == extent_map_block_end(prev)))) {
-               return 1;
-       }
-       return 0;
+       if (extent_map_end(prev) != next->start)
+               return false;
+
+       if (prev->flags != next->flags)
+               return false;
+
+       if (next->block_start < EXTENT_MAP_LAST_BYTE - 1)
+               return next->block_start == extent_map_block_end(prev);
+
+       /* HOLES and INLINE extents. */
+       return next->block_start == prev->block_start;
 }
 
 static void try_merge_map(struct extent_map_tree *tree, struct extent_map *em)
@@ -249,7 +249,7 @@ static void try_merge_map(struct extent_map_tree *tree, struct extent_map *em)
                rb = rb_prev(&em->rb_node);
                if (rb)
                        merge = rb_entry(rb, struct extent_map, rb_node);
-               if (rb && can_merge_extent_map(merge) && mergable_maps(merge, em)) {
+               if (rb && can_merge_extent_map(merge) && mergeable_maps(merge, em)) {
                        em->start = merge->start;
                        em->orig_start = merge->orig_start;
                        em->len += merge->len;
@@ -269,7 +269,7 @@ static void try_merge_map(struct extent_map_tree *tree, struct extent_map *em)
        rb = rb_next(&em->rb_node);
        if (rb)
                merge = rb_entry(rb, struct extent_map, rb_node);
-       if (rb && can_merge_extent_map(merge) && mergable_maps(em, merge)) {
+       if (rb && can_merge_extent_map(merge) && mergeable_maps(em, merge)) {
                em->len += merge->len;
                em->block_len += merge->block_len;
                rb_erase_cached(&merge->rb_node, &tree->map);