btrfs-progs: tree-stats: use on-stack path buffer in calc_root_size

We don't need to conserve stack space too much unlike kernel, also
remove one error condition.

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

diff --git a/cmds-inspect-tree-stats.c b/cmds-inspect-tree-stats.c
index 5ec787a..0e2786c 100644 (file)
--- a/cmds-inspect-tree-stats.c
+++ b/cmds-inspect-tree-stats.c
@@ -313,7 +313,7 @@ static int calc_root_size(struct btrfs_root *tree_root, struct btrfs_key *key,
                          int find_inline)
 {
        struct btrfs_root *root;
-       struct btrfs_path *path;
+       struct btrfs_path path;
        struct rb_node *n;
        struct timeval start, end, diff = {0};
        struct root_stats stat;
@@ -327,31 +327,26 @@ static int calc_root_size(struct btrfs_root *tree_root, struct btrfs_key *key,
                return 1;
        }
 
-       path = btrfs_alloc_path();
-       if (!path) {
-               error("could not allocate path");
-               return 1;
-       }
-
+       btrfs_init_path(&path);
        memset(&stat, 0, sizeof(stat));
        level = btrfs_header_level(root->node);
        stat.lowest_bytenr = btrfs_header_bytenr(root->node);
        stat.highest_bytenr = stat.lowest_bytenr;
        stat.min_cluster_size = (u64)-1;
        stat.max_cluster_size = root->nodesize;
-       path->nodes[level] = root->node;
+       path.nodes[level] = root->node;
        if (gettimeofday(&start, NULL)) {
                error("cannot get time: %s", strerror(errno));
                goto out;
        }
        if (!level) {
-               ret = walk_leaf(root, path, &stat, find_inline);
+               ret = walk_leaf(root, &path, &stat, find_inline);
                if (ret)
                        goto out;
                goto out_print;
        }
 
-       ret = walk_nodes(root, path, &stat, level, find_inline);
+       ret = walk_nodes(root, &path, &stat, level, find_inline);
        if (ret)
                goto out;
        if (gettimeofday(&end, NULL)) {
@@ -417,13 +412,11 @@ out:
        }
 
        /*
-        * We only use path to save node data in iterating,
-        * without holding eb's ref_cnt in path.
-        * Don't use btrfs_free_path() here, it will free these
-        * eb again, and cause many problems, as negative ref_cnt
-        * or invalid memory access.
+        * We only use path to save node data in iterating, without holding
+        * eb's ref_cnt in path.  Don't use btrfs_release_path() here, it will
+        * free these eb again, and cause many problems, as negative ref_cnt or
+        * invalid memory access.
         */
-       free(path);
        return ret;
 }