Implemented handling AUFS whiteouts for copy backend. Review: https://reviews.apache.org/r/53115
Project: http://git-wip-us.apache.org/repos/asf/mesos/repo Commit: http://git-wip-us.apache.org/repos/asf/mesos/commit/0f4c15ad Tree: http://git-wip-us.apache.org/repos/asf/mesos/tree/0f4c15ad Diff: http://git-wip-us.apache.org/repos/asf/mesos/diff/0f4c15ad Branch: refs/heads/master Commit: 0f4c15ad735e437a8e8b9bb6846025aea02c765b Parents: 3800cfd Author: Qian Zhang <zhang...@cn.ibm.com> Authored: Sat Oct 22 21:45:44 2016 +0800 Committer: Qian Zhang <zhq527...@gmail.com> Committed: Sat Nov 5 16:18:30 2016 +0800 ---------------------------------------------------------------------- .../mesos/provisioner/backends/copy.cpp | 103 ++++++++++++++++++- 1 file changed, 98 insertions(+), 5 deletions(-) ---------------------------------------------------------------------- http://git-wip-us.apache.org/repos/asf/mesos/blob/0f4c15ad/src/slave/containerizer/mesos/provisioner/backends/copy.cpp ---------------------------------------------------------------------- diff --git a/src/slave/containerizer/mesos/provisioner/backends/copy.cpp b/src/slave/containerizer/mesos/provisioner/backends/copy.cpp index 9c5354e..7e98110 100644 --- a/src/slave/containerizer/mesos/provisioner/backends/copy.cpp +++ b/src/slave/containerizer/mesos/provisioner/backends/copy.cpp @@ -16,6 +16,8 @@ #include <list> +#include <mesos/docker/spec.hpp> + #include <process/collect.hpp> #include <process/defer.hpp> #include <process/dispatch.hpp> @@ -24,7 +26,6 @@ #include <process/process.hpp> #include <process/subprocess.hpp> - #include <stout/foreach.hpp> #include <stout/os.hpp> @@ -32,7 +33,6 @@ #include "slave/containerizer/mesos/provisioner/backends/copy.hpp" - using namespace process; using std::string; @@ -128,9 +128,92 @@ Future<Nothing> CopyBackendProcess::provision( Future<Nothing> CopyBackendProcess::_provision( - string layer, - const string& rootfs) + string layer, + const string& rootfs) { + // Traverse the layer to check if there is any whiteout files, if + // yes, remove the corresponding files/directories from the rootfs. + // Note: We assume all image types use AUFS whiteout format. + char* source[] = {const_cast<char*>(layer.c_str()), nullptr}; + + FTS* tree = ::fts_open(source, FTS_NOCHDIR | FTS_PHYSICAL, nullptr); + if (tree == nullptr) { + return Failure("Failed to open '" + layer + "': " + os::strerror(errno)); + } + + vector<string> whiteouts; + for (FTSENT *node = ::fts_read(tree); + node != nullptr; node = ::fts_read(tree)) { + if (node->fts_info != FTS_F) { + continue; + } + + if (!strings::startsWith(node->fts_name, docker::spec::WHITEOUT_PREFIX)) { + continue; + } + + string ftsPath = string(node->fts_path); + Path whiteout = Path(ftsPath.substr(layer.length() + 1)); + + // Keep the relative paths of the whiteout files, we will + // remove them from rootfs after layer is copied to rootfs. + whiteouts.push_back(whiteout.string()); + + if (node->fts_name == string(docker::spec::WHITEOUT_OPAQUE_PREFIX)) { + const string path = path::join(rootfs, Path(whiteout).dirname()); + + // Remove the entries under the directory labeled + // as opaque whiteout from rootfs. + Try<Nothing> rmdir = os::rmdir(path, true, false); + if (rmdir.isError()) { + ::fts_close(tree); + return Failure( + "Failed to remove the entries under the directory labeled as" + " opaque whiteout '" + path + "': " + rmdir.error()); + } + } else { + const string path = path::join( + rootfs, + whiteout.dirname(), + whiteout.basename().substr(strlen(docker::spec::WHITEOUT_PREFIX))); + + // The file/directory labeled as whiteout may have already been + // removed with the code above due to its parent directory labeled + // as opaque whiteout, so here we need to check if it still exists + // before trying to remove it. + if (os::exists(path)) { + if (os::stat::isdir(path)) { + Try<Nothing> rmdir = os::rmdir(path); + if (rmdir.isError()) { + ::fts_close(tree); + return Failure( + "Failed to remove the directory labeled as whiteout '" + + path + "': " + rmdir.error()); + } + } else { + Try<Nothing> rm = os::rm(path); + if (rm.isError()) { + ::fts_close(tree); + return Failure( + "Failed to remove the file labeled as whiteout '" + + path + "': " + rm.error()); + } + } + } + } + } + + if (errno != 0) { + Error error = ErrnoError(); + ::fts_close(tree); + return Failure(error); + } + + if (::fts_close(tree) != 0) { + return Failure( + "Failed to stop traversing file system: " + os::strerror(errno)); + } + VLOG(1) << "Copying layer path '" << layer << "' to rootfs '" << rootfs << "'"; @@ -160,7 +243,7 @@ Future<Nothing> CopyBackendProcess::_provision( Subprocess cp = s.get(); return cp.status() - .then([cp](const Option<int>& status) -> Future<Nothing> { + .then([=](const Option<int>& status) -> Future<Nothing> { if (status.isNone()) { return Failure("Failed to reap subprocess to copy image"); } else if (status.get() != 0) { @@ -170,6 +253,16 @@ Future<Nothing> CopyBackendProcess::_provision( }); } + // Remove the whiteout files from rootfs. + foreach (const string whiteout, whiteouts) { + Try<Nothing> rm = os::rm(path::join(rootfs, whiteout)); + if (rm.isError()) { + return Failure( + "Failed to remove whiteout file '" + + whiteout + "': " + rm.error()); + } + } + return Nothing(); }); }
