mke2fs: store checksum seed at format time

Allow users to turn on metadata_csum_seed at format time so that UUIDs
can be live-changed at any time.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/misc/mke2fs.c b/misc/mke2fs.c
index 082a590..3ab4729 100644 (file)
--- a/misc/mke2fs.c
+++ b/misc/mke2fs.c
@@ -1088,7 +1088,8 @@ static __u32 ok_features[3] = {
                EXT4_FEATURE_INCOMPAT_MMP |
                EXT4_FEATURE_INCOMPAT_64BIT|
                EXT4_FEATURE_INCOMPAT_INLINE_DATA|
-               EXT4_FEATURE_INCOMPAT_ENCRYPT,
+               EXT4_FEATURE_INCOMPAT_ENCRYPT |
+               EXT4_FEATURE_INCOMPAT_CSUM_SEED,
        /* R/O compat */
        EXT2_FEATURE_RO_COMPAT_LARGE_FILE|
                EXT4_FEATURE_RO_COMPAT_HUGE_FILE|
@@ -2802,6 +2803,13 @@ int main (int argc, char *argv[])
                                 "Pass -O 64bit to rectify.\n"));
        }
 
+       if (ext2fs_has_feature_csum_seed(fs->super) &&
+           !ext2fs_has_feature_metadata_csum(fs->super)) {
+               printf("%s", _("The metadata_csum_seed feature "
+                              "requres the metadata_csum feature.\n"));
+               exit(1);
+       }
+
        /* Calculate journal blocks */
        if (!journal_device && ((journal_size) ||
            ext2fs_has_feature_journal(&fs_param)))
@@ -2857,6 +2865,11 @@ int main (int argc, char *argv[])
                }
        } else
                uuid_generate(fs->super->s_uuid);
+
+       if (ext2fs_has_feature_csum_seed(fs->super))
+               fs->super->s_checksum_seed = ext2fs_crc32c_le(~0,
+                               fs->super->s_uuid, sizeof(fs->super->s_uuid));
+
        ext2fs_init_csum_seed(fs);
 
        /*