tune2fs: Update the block group checksums when changing the UUID

Since the block group checksums depend on the UUID, we need to update
the block group checksums when setting the UUID.  We only do so if all
of the checksums are correct, however.

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

diff --git a/misc/tune2fs.c b/misc/tune2fs.c
index a130c14..b29b344 100644 (file)
--- a/misc/tune2fs.c
+++ b/misc/tune2fs.c
@@ -1610,6 +1610,22 @@ retry_open:
                add_journal(fs);
 
        if (U_flag) {
+               int set_csum = 0;
+               dgrp_t i;
+
+               if (sb->s_feature_ro_compat &
+                   EXT4_FEATURE_RO_COMPAT_GDT_CSUM) {
+                       /* 
+                        * Determine if the block group checksums are
+                        * correct so we know whether or not to set
+                        * them later on.
+                        */
+                       for (i = 0; i < fs->group_desc_count; i++)
+                               if (!ext2fs_group_desc_csum_verify(fs, i))
+                                       break;
+                       if (i >= fs->group_desc_count)
+                               set_csum = 1;
+               }
                if ((strcasecmp(new_UUID, "null") == 0) ||
                    (strcasecmp(new_UUID, "clear") == 0)) {
                        uuid_clear(sb->s_uuid);
@@ -1621,6 +1637,11 @@ retry_open:
                        com_err(program_name, 0, _("Invalid UUID format\n"));
                        exit(1);
                }
+               if (set_csum) {
+                       for (i = 0; i < fs->group_desc_count; i++)
+                               ext2fs_group_desc_csum_set(fs, i);
+                       fs->flags &= ~EXT2_FLAG_SUPER_ONLY;
+               }
                ext2fs_mark_super_dirty(fs);
        }
        if (I_flag) {