fs: btrfs: Imeplement btrfs_list_subvols() using new infrastructure

Reimplement btrfs_list_subvols() to use new code.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Marek Behún <marek.behun@nic.cz>

diff --git a/fs/btrfs/subvolume.c b/fs/btrfs/subvolume.c
index 258c3da..6fc28d5 100644 (file)
--- a/fs/btrfs/subvolume.c
+++ b/fs/btrfs/subvolume.c
@@ -155,6 +155,72 @@ out:
        return ret;
 }
 
+static int list_subvolums(struct btrfs_fs_info *fs_info)
+{
+       struct btrfs_root *tree_root = fs_info->tree_root;
+       struct btrfs_root *root;
+       struct btrfs_path path;
+       struct btrfs_key key;
+       char *result;
+       int ret = 0;
+
+       result = malloc(PATH_MAX);
+       if (!result)
+               return -ENOMEM;
+
+       ret = list_one_subvol(fs_info->fs_root, result);
+       if (ret < 0)
+               goto out;
+       root = fs_info->fs_root;
+       printf("ID %llu gen %llu path %.*s\n",
+               root->root_key.objectid, btrfs_root_generation(&root->root_item),
+               PATH_MAX, result);
+
+       key.objectid = BTRFS_FIRST_FREE_OBJECTID;
+       key.type = BTRFS_ROOT_ITEM_KEY;
+       key.offset = 0;
+       btrfs_init_path(&path);
+       ret = btrfs_search_slot(NULL, tree_root, &key, &path, 0, 0);
+       if (ret < 0)
+               goto out;
+       while (1) {
+               if (path.slots[0] >= btrfs_header_nritems(path.nodes[0]))
+                       goto next;
+
+               btrfs_item_key_to_cpu(path.nodes[0], &key, path.slots[0]);
+               if (key.objectid > BTRFS_LAST_FREE_OBJECTID)
+                       break;
+               if (key.objectid < BTRFS_FIRST_FREE_OBJECTID ||
+                   key.type != BTRFS_ROOT_ITEM_KEY)
+                       goto next;
+               key.offset = (u64)-1;
+               root = btrfs_read_fs_root(fs_info, &key);
+               if (IS_ERR(root)) {
+                       ret = PTR_ERR(root);
+                       if (ret == -ENOENT)
+                               goto next;
+               }
+               ret = list_one_subvol(root, result);
+               if (ret < 0)
+                       goto out;
+               printf("ID %llu gen %llu path %.*s\n",
+                       root->root_key.objectid,
+                       btrfs_root_generation(&root->root_item),
+                       PATH_MAX, result);
+next:
+               ret = btrfs_next_item(tree_root, &path);
+               if (ret < 0)
+                       goto out;
+               if (ret > 0) {
+                       ret = 0;
+                       break;
+               }
+       }
+out:
+       free(result);
+       return ret;
+}
+
 static int get_subvol_name(u64 subvolid, char *name, int max_len)
 {
        struct btrfs_root_ref rref;
@@ -268,10 +334,12 @@ static void list_subvols(u64 tree, char *nameptr, int max_name_len, int level)
 
 void btrfs_list_subvols(void)
 {
-       char *nameptr = malloc(4096);
-
-       list_subvols(BTRFS_FS_TREE_OBJECTID, nameptr, nameptr ? 4096 : 0, 40);
+       struct btrfs_fs_info *fs_info = current_fs_info;
+       int ret;
 
-       if (nameptr)
-               free(nameptr);
+       if (!fs_info)
+               return;
+       ret = list_subvolums(fs_info);
+       if (ret < 0)
+               error("failed to list subvolume: %d", ret);
 }