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-rw-r--r--fs/ext4/bitmap.c98
1 files changed, 98 insertions, 0 deletions
diff --git a/fs/ext4/bitmap.c b/fs/ext4/bitmap.c
new file mode 100644
index 000000000..f63e028c6
--- /dev/null
+++ b/fs/ext4/bitmap.c
@@ -0,0 +1,98 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * linux/fs/ext4/bitmap.c
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ */
+
+#include <linux/buffer_head.h>
+#include "ext4.h"
+
+unsigned int ext4_count_free(char *bitmap, unsigned int numchars)
+{
+ return numchars * BITS_PER_BYTE - memweight(bitmap, numchars);
+}
+
+int ext4_inode_bitmap_csum_verify(struct super_block *sb, ext4_group_t group,
+ struct ext4_group_desc *gdp,
+ struct buffer_head *bh, int sz)
+{
+ __u32 hi;
+ __u32 provided, calculated;
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
+
+ if (!ext4_has_metadata_csum(sb))
+ return 1;
+
+ provided = le16_to_cpu(gdp->bg_inode_bitmap_csum_lo);
+ calculated = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz);
+ if (sbi->s_desc_size >= EXT4_BG_INODE_BITMAP_CSUM_HI_END) {
+ hi = le16_to_cpu(gdp->bg_inode_bitmap_csum_hi);
+ provided |= (hi << 16);
+ } else
+ calculated &= 0xFFFF;
+
+ return provided == calculated;
+}
+
+void ext4_inode_bitmap_csum_set(struct super_block *sb, ext4_group_t group,
+ struct ext4_group_desc *gdp,
+ struct buffer_head *bh, int sz)
+{
+ __u32 csum;
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
+
+ if (!ext4_has_metadata_csum(sb))
+ return;
+
+ csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz);
+ gdp->bg_inode_bitmap_csum_lo = cpu_to_le16(csum & 0xFFFF);
+ if (sbi->s_desc_size >= EXT4_BG_INODE_BITMAP_CSUM_HI_END)
+ gdp->bg_inode_bitmap_csum_hi = cpu_to_le16(csum >> 16);
+}
+
+int ext4_block_bitmap_csum_verify(struct super_block *sb, ext4_group_t group,
+ struct ext4_group_desc *gdp,
+ struct buffer_head *bh)
+{
+ __u32 hi;
+ __u32 provided, calculated;
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
+ int sz = EXT4_CLUSTERS_PER_GROUP(sb) / 8;
+
+ if (!ext4_has_metadata_csum(sb))
+ return 1;
+
+ provided = le16_to_cpu(gdp->bg_block_bitmap_csum_lo);
+ calculated = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz);
+ if (sbi->s_desc_size >= EXT4_BG_BLOCK_BITMAP_CSUM_HI_END) {
+ hi = le16_to_cpu(gdp->bg_block_bitmap_csum_hi);
+ provided |= (hi << 16);
+ } else
+ calculated &= 0xFFFF;
+
+ if (provided == calculated)
+ return 1;
+
+ return 0;
+}
+
+void ext4_block_bitmap_csum_set(struct super_block *sb, ext4_group_t group,
+ struct ext4_group_desc *gdp,
+ struct buffer_head *bh)
+{
+ int sz = EXT4_CLUSTERS_PER_GROUP(sb) / 8;
+ __u32 csum;
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
+
+ if (!ext4_has_metadata_csum(sb))
+ return;
+
+ csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz);
+ gdp->bg_block_bitmap_csum_lo = cpu_to_le16(csum & 0xFFFF);
+ if (sbi->s_desc_size >= EXT4_BG_BLOCK_BITMAP_CSUM_HI_END)
+ gdp->bg_block_bitmap_csum_hi = cpu_to_le16(csum >> 16);
+}