ref: e512652b7c6a999b13ae526b39b6d93dc8dfbe2b
parent: e9ef4e35940f806cd40959d5b641d6687fa93b17
author: ngkaho1234 <[email protected]>
date: Sat Oct 24 16:33:39 EDT 2015
METADATA_CSUM: Extended Attribute added.
--- a/lwext4/ext4_xattr.c
+++ b/lwext4/ext4_xattr.c
@@ -40,6 +40,7 @@
#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"
@@ -111,6 +112,50 @@
header->h_hash = to_le32(hash);
}
+static uint32_t
+ext4_xattr_block_checksum(struct ext4_inode_ref *inode_ref,
+ ext4_fsblk_t blocknr,
+ struct ext4_xattr_header *header)
+{+ uint32_t checksum = 0;
+ uint64_t le64_blocknr = blocknr;
+ struct ext4_sblock *sb = &inode_ref->fs->sb;
+
+ if (ext4_sb_has_feature_read_only(sb,
+ EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) {+ uint32_t orig_checksum, checksum;
+
+ /* Preparation: temporarily set bg checksum to 0 */
+ orig_checksum = header->h_checksum;
+ header->h_checksum = 0;
+ /* First calculate crc32 checksum against fs uuid */
+ checksum = ext4_crc32c(~0, sb->uuid, sizeof(sb->uuid));
+ /* Then calculate crc32 checksum block number */
+ checksum = ext4_crc32c(checksum, &le64_blocknr,
+ sizeof(le64_blocknr));
+ /* Finally calculate crc32 checksum against
+ * the entire xattr block */
+ checksum = ext4_crc32c(checksum, header,
+ ext4_sb_get_block_size(sb));
+ header->h_checksum = orig_checksum;
+ }
+ return checksum;
+}
+
+static void
+ext4_xattr_set_block_checksum(struct ext4_inode_ref *inode_ref,
+ ext4_fsblk_t blocknr,
+ struct ext4_xattr_header *header)
+{+ struct ext4_sblock *sb = &inode_ref->fs->sb;
+ if (!ext4_sb_has_feature_read_only(sb,
+ EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+ return;
+
+ header->h_checksum =
+ ext4_xattr_block_checksum(inode_ref, blocknr, header);
+}
+
static int ext4_xattr_item_cmp(struct ext4_xattr_item *a,
struct ext4_xattr_item *b)
{@@ -658,6 +703,9 @@
if (block_modified) {ext4_xattr_rehash(block_header,
EXT4_XATTR_BFIRST(&xattr_ref->block));
+ ext4_xattr_set_block_checksum(xattr_ref->inode_ref,
+ xattr_ref->block.lb_id,
+ block_header);
xattr_ref->block.dirty = true;
}