rm-rf: optionally fsync() after removing directory tree

src/shared/rm-rf.c

@@ -250,6 +250,9 @@ int rm_rf_children(
                         ret = r;
         }
 
+        if (FLAGS_SET(flags, REMOVE_SYNCFS) && syncfs(dirfd(d)) < 0 && ret >= 0)
+                ret = -errno;
+
         return ret;
 }
 

src/shared/rm-rf.h

@@ -14,6 +14,7 @@ typedef enum RemoveFlags {
         REMOVE_MISSING_OK       = 1 << 4, /* If the top-level directory is missing, ignore the ENOENT for it */
         REMOVE_CHMOD            = 1 << 5, /* chmod() for write access if we cannot delete or access something */
         REMOVE_CHMOD_RESTORE    = 1 << 6, /* Restore the old mode before returning */
+        REMOVE_SYNCFS           = 1 << 7, /* syncfs() the root of the specified directory after removing everything in it */
 } RemoveFlags;
 
 int unlinkat_harder(int dfd, const char *filename, int unlink_flags, RemoveFlags remove_flags);