btrfs-progs: dump-tree: simplify and fix check for empty uuid

Counting non-zero bytes is wasteful, besides that it would not recognize
uuids containing a 00 value.

Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/print-tree.c b/print-tree.c
index 0f55607..4ecf100 100644 (file)
--- a/print-tree.c
+++ b/print-tree.c
@@ -516,15 +516,14 @@ static void print_root_ref(struct extent_buffer *leaf, int slot, char *tag)
               namelen, namebuf);
 }
 
-static int count_bytes(void *buf, int len, char b)
+static int empty_uuid(const u8 *uuid)
 {
-       int cnt = 0;
        int i;
-       for (i = 0; i < len; i++) {
-               if (((char*)buf)[i] == b)
-                       cnt++;
-       }
-       return cnt;
+
+       for (i = 0; i < BTRFS_UUID_SIZE; i++)
+               if (uuid[i])
+                       return 0;
+       return 1;
 }
 
 /*
@@ -570,11 +569,11 @@ static void print_root(struct extent_buffer *leaf, int slot)
        if (root_item.generation == root_item.generation_v2) {
                uuid_unparse(root_item.uuid, uuid_str);
                printf("\t\tuuid %s\n", uuid_str);
-               if (count_bytes(root_item.parent_uuid, BTRFS_UUID_SIZE, 0) != BTRFS_UUID_SIZE) {
+               if (!empty_uuid(root_item.parent_uuid)) {
                        uuid_unparse(root_item.parent_uuid, uuid_str);
                        printf("\t\tparent_uuid %s\n", uuid_str);
                }
-               if (count_bytes(root_item.received_uuid, BTRFS_UUID_SIZE, 0) != BTRFS_UUID_SIZE) {
+               if (!empty_uuid(root_item.received_uuid)) {
                        uuid_unparse(root_item.received_uuid, uuid_str);
                        printf("\t\treceived_uuid %s\n", uuid_str);
                }