[PATCH 07/22] ext4: Create bitmap checksum helper functions

[Darrick J. Wong]

These helper functions will be used to calculate and verify the block and inode
bitmap checksums.

Signed-off-by: Darrick J. Wong <djwong@xxxxxxxxxx>
---
 fs/ext4/bitmap.c |   13 +++++++++++++
 1 files changed, 13 insertions(+), 0 deletions(-)


diff --git a/fs/ext4/bitmap.c b/fs/ext4/bitmap.c
index fa3af81..285d23a 100644
--- a/fs/ext4/bitmap.c
+++ b/fs/ext4/bitmap.c
@@ -29,3 +29,16 @@ unsigned int ext4_count_free(struct buffer_head *map, unsigned int numchars)
 
 #endif  /*  EXT4FS_DEBUG  */
 
+static __u32 ext4_bitmap_csum(struct super_block *sb, ext4_group_t group,
+			      struct buffer_head *bh, int sz)
+{
+	__u32 csum;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+
+	group = cpu_to_le32(group);
+	csum = ext4_chksum(sbi, sbi->s_uuid_csum, (__u8 *)&group,
+			   sizeof(group));
+	csum = ext4_chksum(sbi, csum, (__u8 *)bh->b_data, sz);
+
+	return csum;
+}

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