fs-util: add fsync_full() helper

We usually combine an fsync() with fsync_directory_of_file() hence let's
add a helper that does both in one.

src/basic/fs-util.c

@@ -1298,6 +1298,17 @@ int fsync_directory_of_file(int fd) {
         return 0;
 }
 
+int fsync_full(int fd) {
+        int r, q;
+
+        /* Sync both the file and the directory */
+
+        r = fsync(fd) < 0 ? -errno : 0;
+        q = fsync_directory_of_file(fd);
+
+        return r < 0 ? r : q;
+}
+
 int fsync_path_at(int at_fd, const char *path) {
         _cleanup_close_ int opened_fd = -1;
         int fd;

src/basic/fs-util.h

@@ -114,6 +114,7 @@ void unlink_tempfilep(char (*p)[]);
 int unlinkat_deallocate(int fd, const char *name, int flags);
 
 int fsync_directory_of_file(int fd);
+int fsync_full(int fd);
 int fsync_path_at(int at_fd, const char *path);
 
 int syncfs_path(int atfd, const char *path);