libbtrfsutil: add btrfs_util_deleted_subvolumes()

[platform/upstream/btrfs-progs.git] / libbtrfsutil / subvolume.c

diff --git a/libbtrfsutil/subvolume.c b/libbtrfsutil/subvolume.c
index 56cd2c6..d972828 100644 (file)
--- a/libbtrfsutil/subvolume.c
+++ b/libbtrfsutil/subvolume.c
@@ -1279,3 +1279,92 @@ PUBLIC enum btrfs_util_error btrfs_util_subvolume_iterator_next_info(struct btrf
 
        return btrfs_util_subvolume_info_fd(iter->fd, id, subvol);
 }
+
+PUBLIC enum btrfs_util_error btrfs_util_deleted_subvolumes(const char *path,
+                                                          uint64_t **ids,
+                                                          size_t *n)
+{
+       enum btrfs_util_error err;
+       int fd;
+
+       fd = open(path, O_RDONLY);
+       if (fd == -1)
+               return BTRFS_UTIL_ERROR_OPEN_FAILED;
+
+       err = btrfs_util_deleted_subvolumes_fd(fd, ids, n);
+       SAVE_ERRNO_AND_CLOSE(fd);
+       return err;
+}
+
+PUBLIC enum btrfs_util_error btrfs_util_deleted_subvolumes_fd(int fd,
+                                                             uint64_t **ids,
+                                                             size_t *n)
+{
+       size_t capacity = 0;
+       struct btrfs_ioctl_search_args search = {
+               .key = {
+                       .tree_id = BTRFS_ROOT_TREE_OBJECTID,
+                       .min_objectid = BTRFS_ORPHAN_OBJECTID,
+                       .max_objectid = BTRFS_ORPHAN_OBJECTID,
+                       .min_type = BTRFS_ORPHAN_ITEM_KEY,
+                       .max_type = BTRFS_ORPHAN_ITEM_KEY,
+                       .min_offset = 0,
+                       .max_offset = UINT64_MAX,
+                       .min_transid = 0,
+                       .max_transid = UINT64_MAX,
+                       .nr_items = 0,
+               },
+       };
+       enum btrfs_util_error err;
+       size_t items_pos = 0, buf_off = 0;
+       int ret;
+
+       *ids = NULL;
+       *n = 0;
+       for (;;) {
+               const struct btrfs_ioctl_search_header *header;
+
+               if (items_pos >= search.key.nr_items) {
+                       search.key.nr_items = 4096;
+                       ret = ioctl(fd, BTRFS_IOC_TREE_SEARCH, &search);
+                       if (ret == -1) {
+                               err = BTRFS_UTIL_ERROR_SEARCH_FAILED;
+                               goto out;
+                       }
+                       items_pos = 0;
+                       buf_off = 0;
+
+                       if (search.key.nr_items == 0)
+                               break;
+               }
+
+               header = (struct btrfs_ioctl_search_header *)(search.buf + buf_off);
+               if (*n >= capacity) {
+                       size_t new_capacity = capacity ? capacity * 2 : 1;
+                       uint64_t *new_ids;
+
+                       new_ids = reallocarray(*ids, new_capacity,
+                                              sizeof(**ids));
+                       if (!new_ids)
+                               return BTRFS_UTIL_ERROR_NO_MEMORY;
+
+                       *ids = new_ids;
+                       capacity = new_capacity;
+               }
+
+               (*ids)[(*n)++] = header->offset;
+
+               items_pos++;
+               buf_off += sizeof(*header) + header->len;
+               search.key.min_offset = header->offset + 1;
+       }
+
+       err = BTRFS_UTIL_OK;
+out:
+       if (err) {
+               free(*ids);
+               *ids = NULL;
+               *n = 0;
+       }
+       return err;
+}