ref: 88853b3b965f6b03cb9a392feabded9ddd8323cc
parent: b4abf659b90682936b698f73f80ffab56e187a40
author: ngkaho1234 <[email protected]>
date: Fri Oct 23 17:48:51 EDT 2015
METADATA_CSUM: block group descriptor checksum added.
--- a/lwext4/ext4_fs.c
+++ b/lwext4/ext4_fs.c
@@ -44,6 +44,7 @@
#include "ext4_errno.h"
#include "ext4_blockdev.h"
#include "ext4_super.h"
+#include "ext4_crc32c.h"
#include "ext4_debug.h"
#include "ext4_block_group.h"
#include "ext4_balloc.h"
@@ -559,7 +560,28 @@
/* Compute the checksum only if the filesystem supports it */
if (ext4_sb_has_feature_read_only(sb,
- EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) {+ EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) {+ /* Use metadata_csum algorithm instead */
+ uint32_t le32_bgid = to_le32(bgid);
+ uint32_t orig_checksum, checksum;
+
+ /* Preparation: temporarily set bg checksum to 0 */
+ orig_checksum = bg->checksum;
+ bg->checksum = 0;
+
+ /* First calculate crc32 checksum against fs uuid */
+ checksum = ext4_crc32c(~0, sb->uuid, sizeof(sb->uuid));
+ /* Then calculate crc32 checksum against bgid */
+ checksum = ext4_crc32c(checksum, (uint8_t *)&le32_bgid,
+ sizeof(bgid));
+ /* Finally calculate crc32 checksum against block_group_desc */
+ checksum = ext4_crc32c(checksum, (uint8_t *)bg,
+ ext4_sb_get_desc_size(sb));
+ bg->checksum = orig_checksum;
+
+ crc = checksum & 0xFFFF;
+ } else if (ext4_sb_has_feature_read_only(sb,
+ EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) {uint8_t *base = (uint8_t *)bg;
uint8_t *checksum = (uint8_t *)&bg->checksum;
@@ -611,6 +633,10 @@
return ext4_block_set(ref->fs->bdev, &ref->block);
}
+/*
+ * BIG FAT NOTES:
+ * Currently we do not verify the checksum of block_group_desc.
+ */
int ext4_fs_get_inode_ref(struct ext4_fs *fs, uint32_t index,
struct ext4_inode_ref *ref)
{