From a2a8a509cd56955c0ce42ba0650d163e0d3eeb82 Mon Sep 17 00:00:00 2001 From: Lennart Poettering Date: Mon, 17 Aug 2020 19:54:38 +0200 Subject: [PATCH] homework: sync everything to disk before we rename LUKS loopback file into place This how this works on Linux: when atomically creating a file we need to fully populate it under a temporary name and then when we are fully done, sync it and the directory it is contained in, before renaming it to the final name. --- src/home/homework-luks.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/src/home/homework-luks.c b/src/home/homework-luks.c index 1eb08e1423..7ce59c8bf3 100644 --- a/src/home/homework-luks.c +++ b/src/home/homework-luks.c @@ -2174,8 +2174,22 @@ int home_create_luks( goto fail; } + /* Sync everything to disk before we move things into place under the final name. */ + if (fsync(image_fd) < 0) { + r = log_error_errno(r, "Failed to synchronize image to disk: %m"); + goto fail; + } + if (disk_uuid_path) (void) ioctl(image_fd, BLKRRPART, 0); + else { + /* If we operate on a file, sync the contaning directory too. */ + r = fsync_directory_of_file(image_fd); + if (r < 0) { + log_error_errno(r, "Failed to synchronize directory of image file to disk: %m"); + goto fail; + } + } /* Let's close the image fd now. If we are operating on a real block device this will release the BSD * lock that ensures udev doesn't interfere with what we are doing */