fs-posix: Added "dirs" parameter to enable explicit directory removal.

src/lib-fs/fs-posix.c

@@ -35,6 +35,7 @@ struct posix_fs {
 	enum fs_posix_lock_method lock_method;
 	mode_t mode;
 	bool mode_auto;
+	bool have_dirs;
 };
 
 struct posix_fs_file {
@@ -100,6 +101,8 @@ fs_posix_init(struct fs *_fs, const char *args, const struct fs_settings *set)
 			fs->path_prefix = i_strdup(arg + 7);
 		} else if (strcmp(arg, "mode=auto") == 0) {
 			fs->mode_auto = TRUE;
+		} else if (strcmp(arg, "dirs") == 0) {
+			fs->have_dirs = TRUE;
 		} else if (strncmp(arg, "mode=", 5) == 0) {
 			unsigned int mode;
 			if (str_to_uint_oct(arg+5, &mode) < 0) {
@@ -129,13 +132,21 @@ static void fs_posix_deinit(struct fs *_fs)
 	i_free(fs);
 }
 
-static enum fs_properties fs_posix_get_properties(struct fs *fs ATTR_UNUSED)
+static enum fs_properties fs_posix_get_properties(struct fs *_fs)
 {
-	/* FS_PROPERTY_DIRECTORIES not returned because fs_delete()
-	   automatically rmdir()s parents. This could be changed later though,
-	   but SIS code at least would need to be changed to support it. */
-	return FS_PROPERTY_LOCKS | FS_PROPERTY_FASTCOPY | FS_PROPERTY_RENAME |
+	struct posix_fs *fs = (struct posix_fs *)_fs;
+	enum fs_properties props =
+		FS_PROPERTY_LOCKS | FS_PROPERTY_FASTCOPY | FS_PROPERTY_RENAME |
 		FS_PROPERTY_STAT | FS_PROPERTY_ITER | FS_PROPERTY_RELIABLEITER;
+
+	/* FS_PROPERTY_DIRECTORIES is not returned normally because fs_delete()
+	   automatically rmdir()s parents. For backwards compatibility
+	   (especially with SIS code) we'll do it that way, but optionally with
+	   "dirs" parameter enable them. This is especially important to be
+	   able to use doveadm fs commands to delete empty directories. */
+	if (fs->have_dirs)
+		props |= FS_PROPERTY_DIRECTORIES;
+	return props;
 }
 
 static int
@@ -197,6 +208,8 @@ static int fs_posix_rmdir_parents(struct posix_fs *fs, const char *path)
 {
 	const char *p;
 
+	if (fs->have_dirs)
+		return 0;
 	if (fs->root_path == NULL && fs->path_prefix == NULL)
 		return 0;