mke2fs: prohibit file system features not supported by the HURD

There are certain file system features which can not be supported by
the HURD, since they use fields in the inode which have been claimed
by HURD-specific features (i.e., such as the author field).  We will
mask out those features so they are not enabled by accident, but if the
user tries to explicitly specify them we will issue an error message.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

diff --git a/misc/mke2fs.c b/misc/mke2fs.c
index d4b396b..69cd999 100644 (file)
--- a/misc/mke2fs.c
+++ b/misc/mke2fs.c
@@ -656,6 +656,23 @@ static void show_stats(ext2_filsys fs)
 }
 
 /*
+ * Returns true if making a file system for the Hurd, else 0
+ */
+static int for_hurd(const char *os)
+{
+       if (!os) {
+#ifdef __GNU__
+               return 1;
+#else
+               return 0;
+#endif
+       }
+       if (isdigit(*os))
+               return (atoi(os) == EXT2_OS_HURD);
+       return (strcasecmp(os, "GNU") == 0 || strcasecmp(os, "hurd") == 0);
+}
+
+/*
  * Set the S_CREATOR_OS field.  Return true if OS is known,
  * otherwise, 0.
  */
@@ -1027,15 +1044,11 @@ static char **parse_fs_type(const char *fs_type,
        const char      *size_type;
        struct str_list list;
        unsigned long long meg;
-       int             is_hurd = 0;
+       int             is_hurd = for_hurd(creator_os);
 
        if (init_list(&list))
                return 0;
 
-       if (creator_os && (!strcasecmp(creator_os, "GNU") ||
-                          !strcasecmp(creator_os, "hurd")))
-               is_hurd = 1;
-
        if (fs_type)
                ext_type = fs_type;
        else if (is_hurd)
@@ -1705,10 +1718,40 @@ profile_error:
                tmp = get_string_from_profile(fs_types, "default_features",
                                              "");
        }
+       /* Mask off features which aren't supported by the Hurd */
+       if (for_hurd(creator_os)) {
+               fs_param.s_feature_incompat &= ~EXT2_FEATURE_INCOMPAT_FILETYPE;
+               fs_param.s_feature_ro_compat &=
+                       ~(EXT4_FEATURE_RO_COMPAT_HUGE_FILE |
+                         EXT4_FEATURE_RO_COMPAT_METADATA_CSUM);
+       }
        edit_feature(fs_features ? fs_features : tmp,
                     &fs_param.s_feature_compat);
        if (tmp)
                free(tmp);
+       /*
+        * If the user specified features incompatible with the Hurd, complain
+        */
+       if (for_hurd(creator_os)) {
+               if (fs_param.s_feature_incompat &
+                   EXT2_FEATURE_INCOMPAT_FILETYPE) {
+                       fprintf(stderr, _("The HURD does not support the "
+                                         "filetype feature.\n"));
+                       exit(1);
+               }
+               if (fs_param.s_feature_ro_compat &
+                   EXT4_FEATURE_RO_COMPAT_HUGE_FILE) {
+                       fprintf(stderr, _("The HURD does not support the "
+                                         "huge_file feature.\n"));
+                       exit(1);
+               }
+               if (fs_param.s_feature_ro_compat &
+                   EXT4_FEATURE_RO_COMPAT_METADATA_CSUM) {
+                       fprintf(stderr, _("The HURD does not support the "
+                                         "metadata_csum feature.\n"));
+                       exit(1);
+               }
+       }
 
        /*
         * We now need to do a sanity check of fs_blocks_count for