tune2fs: rewrite block group checksums when changing checksumming feature flags

When toggling the metadata_csum and uninit_bg feature flags, we should
rewrite the block groups with the desired checksum.

Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/misc/tune2fs.c b/misc/tune2fs.c
index bc3f832..3505215 100644 (file)
--- a/misc/tune2fs.c
+++ b/misc/tune2fs.c
@@ -694,8 +694,12 @@ static void rewrite_inodes(ext2_filsys fs)
 
 static void rewrite_metadata_checksums(ext2_filsys fs)
 {
+       int i;
+
        fs->flags |= EXT2_FLAG_IGNORE_CSUM_ERRORS;
        ext2fs_init_csum_seed(fs);
+       for (i = 0; i < fs->group_desc_count; i++)
+               ext2fs_group_desc_csum_set(fs, i);
        rewrite_inodes(fs);
        ext2fs_read_bitmaps(fs);
        ext2fs_mark_ib_dirty(fs);
@@ -710,6 +714,49 @@ static void rewrite_metadata_checksums(ext2_filsys fs)
        ext2fs_mark_super_dirty(fs);
 }
 
+static void enable_uninit_bg(ext2_filsys fs)
+{
+       struct ext2_group_desc *gd;
+       int i;
+
+       for (i = 0; i < fs->group_desc_count; i++) {
+               gd = ext2fs_group_desc(fs, fs->group_desc, i);
+               gd->bg_itable_unused = 0;
+               gd->bg_flags = EXT2_BG_INODE_ZEROED;
+               ext2fs_group_desc_csum_set(fs, i);
+       }
+       fs->flags &= ~EXT2_FLAG_SUPER_ONLY;
+}
+
+static void disable_uninit_bg(ext2_filsys fs, __u32 csum_feature_flag)
+{
+       struct ext2_group_desc *gd;
+       int i;
+
+       /* Load bitmaps to ensure that the uninit ones get written out */
+       fs->super->s_feature_ro_compat |= csum_feature_flag;
+       ext2fs_read_bitmaps(fs);
+       ext2fs_mark_ib_dirty(fs);
+       ext2fs_mark_bb_dirty(fs);
+       fs->super->s_feature_ro_compat &= ~csum_feature_flag;
+
+       for (i = 0; i < fs->group_desc_count; i++) {
+               gd = ext2fs_group_desc(fs, fs->group_desc, i);
+               if ((gd->bg_flags & EXT2_BG_INODE_ZEROED) == 0) {
+                       /*
+                        * XXX what we really should do is zap
+                        * uninitialized inode tables instead.
+                        */
+                       request_fsck_afterwards(fs);
+                       break;
+               }
+               gd->bg_itable_unused = 0;
+               gd->bg_flags = 0;
+               ext2fs_group_desc_csum_set(fs, i);
+       }
+       fs->flags &= ~EXT2_FLAG_SUPER_ONLY;
+}
+
 /*
  * Update the feature set as provided by the user.
  */
@@ -887,6 +934,21 @@ mmp_error:
                if (check_fsck_needed(fs))
                        exit(1);
                rewrite_checksums = 1;
+               /* metadata_csum supersedes uninit_bg */
+               fs->super->s_feature_ro_compat &=
+                       ~EXT4_FEATURE_RO_COMPAT_GDT_CSUM;
+
+               /* if uninit_bg was previously off, rewrite group desc */
+               if (!(old_features[E2P_FEATURE_RO_INCOMPAT] &
+                     EXT4_FEATURE_RO_COMPAT_GDT_CSUM))
+                       enable_uninit_bg(fs);
+
+               /*
+                * Since metadata_csum supersedes uninit_bg, pretend like
+                * uninit_bg has been off all along.
+                */
+               old_features[E2P_FEATURE_RO_INCOMPAT] &=
+                       ~EXT4_FEATURE_RO_COMPAT_GDT_CSUM;
        }
 
        if (FEATURE_OFF(E2P_FEATURE_RO_INCOMPAT,
@@ -894,37 +956,40 @@ mmp_error:
                if (check_fsck_needed(fs))
                        exit(1);
                rewrite_checksums = 1;
+               /*
+                * If we're turning off metadata_csum and not turning on
+                * uninit_bg, rewrite group desc.
+                */
+               if (!(fs->super->s_feature_ro_compat &
+                     EXT4_FEATURE_RO_COMPAT_GDT_CSUM))
+                       disable_uninit_bg(fs,
+                               EXT4_FEATURE_RO_COMPAT_METADATA_CSUM);
+               else
+                       /*
+                        * metadata_csum previously provided uninit_bg, so if
+                        * we're also setting the uninit_bg feature bit,
+                        * pretend like it was previously enabled.  Checksums
+                        * will be rewritten with crc16 later.
+                        */
+                       old_features[E2P_FEATURE_RO_INCOMPAT] |=
+                               EXT4_FEATURE_RO_COMPAT_GDT_CSUM;
        }
 
        if (FEATURE_ON(E2P_FEATURE_RO_INCOMPAT,
                       EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) {
-               for (i = 0; i < fs->group_desc_count; i++) {
-                       gd = ext2fs_group_desc(fs, fs->group_desc, i);
-                       gd->bg_itable_unused = 0;
-                       gd->bg_flags = EXT2_BG_INODE_ZEROED;
-                       ext2fs_group_desc_csum_set(fs, i);
-               }
-               fs->flags &= ~EXT2_FLAG_SUPER_ONLY;
+               /* Do not enable uninit_bg when metadata_csum enabled */
+               if (fs->super->s_feature_ro_compat &
+                   EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)
+                       fs->super->s_feature_ro_compat &=
+                               ~EXT4_FEATURE_RO_COMPAT_GDT_CSUM;
+               else
+                       enable_uninit_bg(fs);
        }
 
        if (FEATURE_OFF(E2P_FEATURE_RO_INCOMPAT,
-                       EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) {
-               for (i = 0; i < fs->group_desc_count; i++) {
-                       gd = ext2fs_group_desc(fs, fs->group_desc, i);
-                       if ((gd->bg_flags & EXT2_BG_INODE_ZEROED) == 0) {
-                               /* 
-                                * XXX what we really should do is zap
-                                * uninitialized inode tables instead.
-                                */
-                               request_fsck_afterwards(fs);
-                               break;
-                       }
-                       gd->bg_itable_unused = 0;
-                       gd->bg_flags = 0;
-                       gd->bg_checksum = 0;
-               }
-               fs->flags &= ~EXT2_FLAG_SUPER_ONLY;
-       }
+                       EXT4_FEATURE_RO_COMPAT_GDT_CSUM))
+               disable_uninit_bg(fs,
+                               EXT4_FEATURE_RO_COMPAT_GDT_CSUM);
 
        if (FEATURE_ON(E2P_FEATURE_RO_INCOMPAT,
                                EXT4_FEATURE_RO_COMPAT_QUOTA)) {
@@ -2498,8 +2563,7 @@ retry_open:
                                exit(1);
                }
 
-               if (sb->s_feature_ro_compat &
-                   EXT4_FEATURE_RO_COMPAT_GDT_CSUM) {
+               if (ext2fs_has_group_desc_csum(fs)) {
                        /*
                         * Determine if the block group checksums are
                         * correct so we know whether or not to set