libbtrfsutil: add btrfs_util_deleted_subvolumes()

Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 89 insertions, 0 deletions

diff --git a/libbtrfsutil/subvolume.c b/libbtrfsutil/subvolume.c
index 56cd2c6d..d9728281 100644
--- 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;
+}