resize2fs: Prohibit the combination of flex_bg and !resize_inode

This is a potentially a difficult case for resize2fs to handle, so
prohibit it for now.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/resize/main.c b/resize/main.c
index d7097ad..1cb0b20 100644
--- a/resize/main.c
+++ b/resize/main.c
@@ -316,9 +316,28 @@
 			"(%s)", device_name);
 		exit(1);
 	}
+
+	/*
+	 * XXXX   The combination of flex_bg and !resize_inode causes
+	 * major problems for resize2fs, since when the group descriptors
+	 * grow in size this can potentially require multiple inode
+	 * tables to be moved aside to make room, and resize2fs chokes
+	 * rather badly in this scenario.  It's a rare combination,
+	 * except when a filesystem is expanded more than a certain
+	 * size, so for now, we'll just prohibit that combination.
+	 * This is something we should fix eventually, though.
+	 */
+	if ((fs->super->s_feature_incompat & EXT4_FEATURE_INCOMPAT_FLEX_BG) &&
+	    !(fs->super->s_feature_compat & EXT2_FEATURE_COMPAT_RESIZE_INODE)) {
+		com_err(program_name, 0, _("%s: The combination of flex_bg "
+					   "and\n\t!resize_inode features "
+					   "is not supported by resize2fs.\n"),
+			device_name);
+		exit(1);
+	}
 	
 	if (print_min_size) {
-		printf("Estimated minimum size of the filesystem: %u\n",
+		printf(_("Estimated minimum size of the filesystem: %u\n"),
 		       calculate_minimum_resize_size(fs));
 		exit(0);
 	}