tune2fs: refuse to unmark flex_bg via clear_ok_features

IIUC, clear_ok_features is the gateway for all features that can be cleared by tune2fs. So refuse to unmark flex_bg via clear_ok_features instead of dealing with it alone. Having flex_bg in clear_ok_features is quite misleading.

index e72518a..c1876d1 100644
@@ -136,8 +136,7 @@ static __u32 clear_ok_features[3] = {
 		EXT2_FEATURE_COMPAT_RESIZE_INODE |
 		EXT2_FEATURE_COMPAT_DIR_INDEX,
 	/* Incompat */
-	EXT2_FEATURE_INCOMPAT_FILETYPE |
-		EXT4_FEATURE_INCOMPAT_FLEX_BG,
+	EXT2_FEATURE_INCOMPAT_FILETYPE,
 	/* R/O compat */
 	EXT2_FEATURE_RO_COMPAT_LARGE_FILE |
 		EXT4_FEATURE_RO_COMPAT_HUGE_FILE|

@@ -407,15 +406,6 @@ static void update_feature_set(ext2_filsys fs, char

*features)
uuid_generate((unsigned char *) sb->s_hash_seed);
}

- if (FEATURE_OFF(E2P_FEATURE_INCOMPAT, EXT4_FEATURE_INCOMPAT_FLEX_BG)) {
- if (ext2fs_check_desc(fs)) {
- fputs(_("Clearing the flex_bg flag would "
- "cause the the filesystem to be\n"
- "inconsistent.\n"), stderr);
- exit(1);
- }
- }
-
if (FEATURE_OFF(E2P_FEATURE_RO_INCOMPAT,
EXT4_FEATURE_RO_COMPAT_HUGE_FILE)) {
if ((mount_flags & EXT2_MF_MOUNTED) &&

Cheers,

Bergwolf

Here lieth one whose name was writ on water.