Method shrink_alloc

src/SimpleRADOSStriper.cc:287–344

}

int SimpleRADOSStriper::shrink_alloc(uint64_t a)
{
  d(5) << dendl;
  std::vector<aiocompletionptr> removes;

  ceph_assert(a <= allocated);
  uint64_t prune = std::max<uint64_t>(a, (1u << object_size)); /* never delete first extent here */
  uint64_t len = allocated - prune;
  const uint64_t bytes_removed = len;
  uint64_t offset = prune;
  while (len > 0) {
    auto ext = get_next_extent(offset, len);
    auto aiocp = aiocompletionptr(librados::Rados::aio_create_completion());
    if (int rc = ioctx.aio_remove(ext.soid, aiocp.get()); rc < 0) {
      d(1) << " aio_remove failed: " << cpp_strerror(rc) << dendl;
      return rc;
    }
    removes.emplace_back(std::move(aiocp));
    len -= ext.len;
    offset += ext.len;
  }

  for (auto& aiocp : removes) {
    if (int rc = aiocp->wait_for_complete(); rc < 0 && rc != -ENOENT) {
      d(1) << " aio_remove failed: " << cpp_strerror(rc) << dendl;
      return rc;
    }
  }

  auto ext = get_first_extent();
  auto op = librados::ObjectWriteOperation();
  auto aiocp = aiocompletionptr(librados::Rados::aio_create_completion());
  op.setxattr(XATTR_ALLOCATED, uint2bl(a));
  d(15) << " updating allocated to " << a << dendl;
  op.setxattr(XATTR_VERSION, uint2bl(version+1));
  d(15) << " updating version to " << (version+1) << dendl;
  if (int rc = ioctx.aio_operate(ext.soid, aiocp.get(), &op); rc < 0) {
    d(1) << " update failed: " << cpp_strerror(rc) << dendl;
    return rc;
  }
  /* we need to wait so we don't have dangling extents */
  d(10) << " waiting for allocated update" << dendl;
  if (int rc = aiocp->wait_for_complete(); rc < 0) {
    d(1) << " update failure: " << cpp_strerror(rc) << dendl;
    return rc;
  }
  if (logger) {
    logger->inc(P_UPDATE_METADATA);
    logger->inc(P_UPDATE_ALLOCATED);
    logger->inc(P_UPDATE_VERSION);
    logger->inc(P_SHRINK);
    logger->inc(P_SHRINK_BYTES, bytes_removed);
  }

  version += 1;
  allocated = a;
  return 0;
}