btrfs-progs: convert: use on-stack path buffer in create_image

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/btrfs-convert.c b/btrfs-convert.c
index 3a5dd12..b827a68 100644 (file)
--- a/btrfs-convert.c
+++ b/btrfs-convert.c
@@ -968,7 +968,7 @@ static int create_image(struct btrfs_root *root,
 {
        struct btrfs_inode_item buf;
        struct btrfs_trans_handle *trans;
-       struct btrfs_path *path = NULL;
+       struct btrfs_path path;
        struct btrfs_key key;
        struct cache_extent *cache;
        struct cache_tree used_tmp;
@@ -985,6 +985,7 @@ static int create_image(struct btrfs_root *root,
                return -ENOMEM;
 
        cache_tree_init(&used_tmp);
+       btrfs_init_path(&path);
 
        ret = btrfs_find_free_objectid(trans, root, BTRFS_FIRST_FREE_OBJECTID,
                                       &ino);
@@ -1001,24 +1002,19 @@ static int create_image(struct btrfs_root *root,
        if (ret < 0)
                goto out;
 
-       path = btrfs_alloc_path();
-       if (!path) {
-               ret = -ENOMEM;
-               goto out;
-       }
        key.objectid = ino;
        key.type = BTRFS_INODE_ITEM_KEY;
        key.offset = 0;
 
-       ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
+       ret = btrfs_search_slot(trans, root, &key, &path, 0, 1);
        if (ret) {
                ret = (ret > 0 ? -ENOENT : ret);
                goto out;
        }
-       read_extent_buffer(path->nodes[0], &buf,
-                       btrfs_item_ptr_offset(path->nodes[0], path->slots[0]),
+       read_extent_buffer(path.nodes[0], &buf,
+                       btrfs_item_ptr_offset(path.nodes[0], path.slots[0]),
                        sizeof(buf));
-       btrfs_release_path(path);
+       btrfs_release_path(&path);
 
        /*
         * Create a new used space cache, which doesn't contain the reserved
@@ -1056,18 +1052,18 @@ static int create_image(struct btrfs_root *root,
        key.objectid = ino;
        key.type = BTRFS_INODE_ITEM_KEY;
        key.offset = 0;
-       ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
+       ret = btrfs_search_slot(trans, root, &key, &path, 0, 1);
        if (ret) {
                ret = (ret > 0 ? -ENOENT : ret);
                goto out;
        }
        btrfs_set_stack_inode_size(&buf, cfg->num_bytes);
-       write_extent_buffer(path->nodes[0], &buf,
-                       btrfs_item_ptr_offset(path->nodes[0], path->slots[0]),
+       write_extent_buffer(path.nodes[0], &buf,
+                       btrfs_item_ptr_offset(path.nodes[0], path.slots[0]),
                        sizeof(buf));
 out:
        free_extent_cache_tree(&used_tmp);
-       btrfs_free_path(path);
+       btrfs_release_path(&path);
        btrfs_commit_transaction(trans, root);
        return ret;
 }